U.S. patent application number 14/036183 was filed with the patent office on 2014-01-30 for magnetron sputtering apparatus.
This patent application is currently assigned to TOKYO ELECTRON LIMITED. Invention is credited to Tetsuya Goto, Takaaki Matsuoka, Tadahiro Ohmi.
Application Number | 20140027278 14/036183 |
Document ID | / |
Family ID | 39863909 |
Filed Date | 2014-01-30 |
United States Patent
Application |
20140027278 |
Kind Code |
A1 |
Ohmi; Tadahiro ; et
al. |
January 30, 2014 |
MAGNETRON SPUTTERING APPARATUS
Abstract
A magnetron sputtering apparatus for processing a substrate
includes a target holding member for holding a target installed to
face the substrate and a magnet installed at a side opposite to the
substrate across the target. In the magnetron sputtering apparatus,
plasma is confined on a surface of the target by forming a magnetic
field on the target surface by the magnet, on the target surface, a
plasma loop is formed around a region on a loop where a vertical
magnetic field component perpendicular to the target does not
substantially exist while a horizontal magnetic field component
parallel to the target mainly exists, and the horizontal magnetic
field component at all position on the loop where the horizontal
magnetic field mainly exists is in a range of about 500 Gauss to
1200 Gauss.
Inventors: |
Ohmi; Tadahiro; (Sendai,
JP) ; Goto; Tetsuya; (Sendai, JP) ; Matsuoka;
Takaaki; (Tokyo, JP) |
Assignee: |
TOKYO ELECTRON LIMITED
Tokyo
JP
NATIONAL UNIVERSITY CORPORATION TOHOKU UNIVERSITY
Sendai-shi
JP
|
Family ID: |
39863909 |
Appl. No.: |
14/036183 |
Filed: |
September 25, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12594676 |
Oct 5, 2009 |
8568577 |
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PCT/JP2008/056819 |
Apr 4, 2008 |
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14036183 |
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Current U.S.
Class: |
204/298.16 |
Current CPC
Class: |
C23C 14/35 20130101;
H01J 37/3455 20130101; H01J 37/3405 20130101 |
Class at
Publication: |
204/298.16 |
International
Class: |
C23C 14/35 20060101
C23C014/35 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 6, 2007 |
JP |
2007-101159 |
Mar 4, 2008 |
JP |
2008-052891 |
Mar 4, 2008 |
JP |
2008-052934 |
Mar 4, 2008 |
JP |
2008-053981 |
Claims
1. A magnetron sputtering apparatus for processing a substrate, the
apparatus comprising: a target holding member for holding a target
installed to face the substrate; and a magnet installed at a side
opposite to the substrate across the target, wherein plasma is
confined on a surface of the target by forming a magnetic field on
the target surface by the magnet, on the target surface, a plasma
loop is formed around a region on a loop where a vertical magnetic
field component perpendicular to the target does not substantially
exist while a horizontal magnetic field component parallel to the
target mainly exists, and the horizontal magnetic field component
at all position on the loop where the horizontal magnetic field
mainly exists is in a range of about 500 Gauss to 1200 Gauss.
2. A magnetron sputtering apparatus for processing a substrate, the
apparatus comprising: a target holding member for holding a target
installed to face the substrate; and a magnet installed at a side
opposite to the substrate across the target, wherein plasma is
confined on a surface of the target by forming a magnetic field on
the target surface by the magnet, on the target surface, a plasma
loop is formed around a region on a loop where a vertical magnetic
field component perpendicular to the target does not substantially
exist while a horizontal magnetic field component parallel to the
target mainly exists, and the horizontal magnetic field component
at all position on the loop where the horizontal magnetic field
mainly exists has a minimum value in a range of about 65% to 100%
of a maximum value.
3. A magnetron sputtering apparatus for processing a substrate, the
apparatus comprising: a target holding member for holding a target
that is arranged to face the substrate when processing the
substrate; and a magnet installed at a side opposite to the
substrate across the target, wherein the magnet comprises: a rotary
magnet body installed around a column-shaped rotation shaft in a
spiral shape; and a stationary outer peripheral body installed in
the vicinity of the rotary magnet body in parallel to a surface of
the target, wherein the rotary magnet body is formed by arranging a
plurality of plate magnets on the column-shaped rotation shaft such
that an N pole of a plate magnet of the plurality of plate magnets
is substantially surrounded by S poles of other plate magnets of
the plurality of plate magnets, plasma is confined on the surface
of the target by forming a magnetic field on the surface of the
target by the magnet, and the rotary magnet body rotates with the
column-shaped rotation shaft, so that a pattern of the magnetic
field on the surface of the target moves as time passes, wherein a
torque applied to the column-shaped rotation shaft due to an
interaction between the rotary magnet body and the stationary outer
peripheral body is in a range of about 0.1 Nm to 100 Nm, the rotary
magnet body includes a plurality of spiral bodies formed around the
column-shaped rotation shaft, and forms a spiral-shaped magnet set
in which adjacent spiral bodies in an axial direction of the
column-shaped rotation shaft have opposite magnetic poles of an N
pole and an S pole on an outer side of the column-shaped rotation
shaft in its diametrical direction, the stationary outer peripheral
body is configured to surround the rotary magnet body, and forms
magnetic poles of an N pole or an S pole on a side facing the
target or it is not previously magnetized, the rotary magnet body
is a spiral-shaped plate magnet set having plate magnets installed
on the column-shaped rotation shaft in a spiral shape to form 2
spirals, adjacent spirals in an axial direction of the
column-shaped rotation shaft have opposite magnetic poles of an N
pole and an S pole on the outer side of the column-shaped rotation
shaft in a diametrical direction of the column-shaped rotation
shaft, the column-shaped rotation shaft is made of a magnetic body
having a hollow structure, and a thickness of the magnetic body is
set such that a magnetic flux density at an entire region in the
magnetic body becomes equal to or less than about 65% of a
saturated magnetic flux density of the magnetic body.
4. The A magnetron sputtering apparatus for processing a substrate,
the apparatus comprising: a target holding member for holding a
target that is arranged to face the substrate when processing the
substrate; and a magnet installed at a side opposite to the
substrate across the target, wherein the magnet comprises: a rotary
magnet body installed around a column-shaped rotation shaft in a
spiral shape; and a stationary outer peripheral body installed in
the vicinity of the rotary magnet body in parallel to a surface of
the target, wherein the rotary magnet body is formed by arranging a
plurality of plate magnets on the column-shaped rotation shaft such
that an N pole of a plate magnet of the plurality of plate magnets
is substantially surrounded by S poles of other plate magnets of
the plurality of plate magnets, plasma is confined on the surface
of the target by forming a magnetic field on the surface of the
target by the magnet, and the rotary magnet body rotates with the
column-shaped rotation shaft, so that a pattern of the magnetic
field on the surface of the target moves as time passes, wherein a
torque applied to the column-shaped rotation shaft due to an
interaction between the rotary magnet body and the stationary outer
peripheral body is in a range of about 0.1 Nm to 100 Nm, the rotary
magnet body includes a plurality of spiral bodies formed around the
column-shaped rotation shaft, and forms a spiral-shaped magnet set
in which adjacent spiral bodies in an axial direction of the
column-shaped rotation shaft have opposite magnetic poles of an N
pole and an S pole on an outer side of the column-shaped rotation
shaft in its diametrical direction, the stationary outer peripheral
body is configured to surround the rotary magnet body, and forms
magnetic poles of an N pole or an S pole on a side facing the
target or it is not previously magnetized, the rotary magnet body
is a spiral-shaped plate magnet set having plate magnets installed
on the column-shaped rotation shaft in a spiral shape to form 2
spirals, adjacent spirals in an axial direction of the
column-shaped rotation shaft have opposite magnetic poles of an N
pole and an S pole on the outer side of the column-shaped rotation
shaft in a diametrical direction of the column-shaped rotation
shaft, the column-shaped rotation shaft is made of a paramagnetic
body having a hollow structure, and a thickness of the paramagnetic
body is set such that a magnetic flux density at an entire region
in the paramagnetic body becomes smaller than a residual magnetic
flux density of the magnet forming the rotary magnet body.
5. A magnetron sputtering apparatus for processing a substrate, the
apparatus comprising: a target holding member for holding a target
installed to face the substrate; and a magnet installed at a side
opposite to the substrate across the target, wherein plasma is
confined on a surface of the target by forming a magnetic field on
the target surface by the magnet, a plurality of plasma loops is
formed on the target surface, a distance between the target surface
and a surface of the substrate is set to be equal to or less than
about 30 mm, and a magnetic field on the substrate surface is set
to be equal to or less than about 100 Gauss.
6. A magnetron sputtering apparatus for processing a substrate, the
apparatus comprising: a target holding unit installed at a side
opposite to the substrate across a target installed to face the
substrate; and a magnet installed to face the target via the target
holding unit, wherein plasma is confined on a surface of the target
by forming a magnetic field on the target surface by the magnet, a
plurality of plasma loops is formed on the target surface, and a
thickness of the target holding unit is set to be equal to or less
than about 30% of an initial thickness of the target.
7. The magnetron sputtering apparatus of claim 6, wherein a first
space between the substrate and the target is capable of being
depressurized, a second space between the target holding unit and
the magnet is capable of being depressurized, and a pressure in the
first space is substantially the same as that in the second space.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This is a divisional application of U.S. patent application
Ser. No. 12/594,676, filed on Oct. 5, 2009 which claims the benefit
of Japanese Patent Application No. 2007-101159, filed on Apr. 6,
2007, Japanese Patent Application No. 2008-052891, filed on Mar. 4,
2008, Japanese Patent Application No. 2008-052934, filed on Mar. 4,
2008 and Japanese Patent Application No. 2008-053981, filed on Mar.
4, 2008, the entire disclosures of which are incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present invention relates to a magnetron sputtering
apparatus which performs a preset surface processing on a target
object such as a liquid crystal display substrate or a
semiconductor substrate.
BACKGROUND ART
[0003] A thin film forming process for forming a thin film of a
metal or an insulating material on a substrate is indispensable in
the manufacture of a semiconductor device such as an IC or a liquid
crystal display device. A film forming method using a sputtering
apparatus is used in the thin film forming process. In this film
forming method, a target made of a raw material for a thin film
formation is used; and an argon gas or the like is excited into
plasma by a DC high voltage or a high frequency power; and the
target is activated by the gas excited into plasma and is
sputtered; and then it is deposited on a target substrate.
[0004] A film forming method using a magnetron sputtering apparatus
is mainly employed as a sputtering film forming method. In this
film forming method, to achieve a high film forming rate, magnets
are arranged on a rear surface of a target such that magnetic force
lines are generated in parallel to each other on a target surface,
thereby confining plasma on the target surface and thus obtaining
high-density plasma.
[0005] FIG. 14 is a configuration view illustrating major
components of such a conventional magnetron sputtering apparatus.
In the figure, a reference numeral 101 denotes a target; 102, a
target substrate on which a thin film is to be formed; 103, a
plurality of magnets; 104, magnetic force lines; and 105, a target
101's area which is eroded, i.e., an erosion area.
[0006] As shown in FIG. 14, the plurality of magnets 103 are
arranged on a rear surface of the target 101 such that their N and
S poles are oriented toward predetermined directions. High
frequency power (RF power) 106 or DC high voltage power 107 is
applied between the target 101 and the substrate 102, so that
plasma is excited on the target 101.
[0007] Meanwhile, the magnetic force lines 104 oriented from N
poles to their adjacent S poles are generated from the plurality of
magnets 103 installed on the rear surface of the target 101. A
horizontal magnetic field (a magnetic force line component parallel
to a target surface) is maximized locally at a position on the
target surface where a vertical magnetic field (a magnetic force
line component perpendicular to the target surface) is zero. In an
area where the horizontal magnetic field component is great,
electrons are confined in the vicinity of the target surface, so
that high-density plasma is obtained. As a result, the erosion area
105 is formed around this area.
[0008] Since the erosion area 105 is exposed to the higher-density
plasma compared to the other areas, consumption of the target 101
tends to be great thereat. As a film formation is continued, a
target material is consumed in this area, so that the entire target
has to be replaced. As a result, the efficiency of the usage of the
target 101 may be deteriorated. Besides, as for the thickness of a
thin film on the target substrate 102 installed to face the target
101, since a film thickness at a position corresponding to the
erosion area 105 is thicker than film thicknesses at the other
areas, the uniformity of the entire film thickness of the target
substrate 102 may also be deteriorated.
[0009] Conventionally, there have been proposed methods in which a
bar magnet is used as a magnet for generating magnetic fields, and
the bar magnet is moved and rotated to move an erosion area as time
passes, so that a local consumption of target is substantially
suppressed. That is, a time average of target consumption is
uniform and the uniformity of the film thickness of a target
substrate is improved (see, for example, Patent Documents 1 to
3).
[0010] In these methods, each bar magnet has a configuration in
which an N pole and an S pole are respectively positioned at
surfaces opposite to each other in its diametric direction while
the same magnetic polarities are respectively arranged in parallel
in its lengthwise direction, or an N pole and an S pole are
respectively positioned at surfaces opposite to each other in its
diametric direction while the same magnetic polarities are
respectively arranged in a spiral shape in its lengthwise
direction. Further, stationary bar magnets are positioned in the
vicinity of moving or rotating bar magnets so that a closed circuit
is formed at an erosion area within the target. Each of these
stationary bar magnets has a configuration in which an N pole and
an S pole are respectively positioned at surfaces opposite to each
other in its diametric direction while the same magnetic polarities
are respectively arranged in parallel in its lengthwise
direction.
[0011] In addition, there has been also proposed a method in which
a plurality of film-formation rotary magnets buried in a spiral
shape is used to continuously form waves of a magnetic field (see,
for example, Patent Document 4).
[0012] Patent Document 1: Japanese Patent Laid-open Publication No.
H5-148642
[0013] Patent Document 2: Japanese Patent Laid-open Publication No.
2000-309867
[0014] Patent Document 3: Japanese Patent No. 3566327
[0015] Patent Document 4: Japanese Patent Laid-open Publication No.
2001-32067
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0016] In the aforementioned conventional methods, however, the
strength of bar magnets needs to be enhanced and the compact bar
magnets need to be arranged more closely to each other, such that
an instantaneous erosion density is increased, i.e., a ratio of
erosion areas to an entire target area becomes high in order to
increase a film forming rate on a target substrate. However, with
such a configuration, magnets or fixing rods may be distorted due
to repulsive or attractive forces between the magnets, or it may be
difficult to move or rotate the magnets against those forces. To
elaborate, an attractive or repulsive force of about 3000 N may be
generated between the magnets, thereby causing some problems. That
is, metals supporting the magnets may be deformed, or a torque of
about 30 Nm may be simultaneously generated whereby a very strong
motor may be needed, or it may become difficult to raise a
rotational speed. These problems cause deterioration of the
uniformity of the film formation or reduction of apparatus
lifetime.
[0017] Further, as the rotary magnet adjacent to its surrounding
stationary bar magnets is rotated, there inevitably occurs a case
where a phase of a magnetic pole of the rotary magnet becomes
identical with a phase of a magnetic pole of the stationary bar
magnet surrounding the rotary magnet. In this case, a closed plasma
region may not be formed.
[0018] Further, in film-formation rotary magnets buried in a spiral
shape, although waves of a magnetic field are formed, a closed
plasma loop may not be formed, or strong forces may be generated
between the adjacent rotary magnets so that it may be difficult to
rotate the magnets against the forces.
[0019] In view of the foregoing, the present invention has been
conceived to solve the above-mentioned problems and provides a
magnetron sputtering apparatus that increases an instantaneous
plasma density on a target to increase a film forming rate.
[0020] Further, the present invention also provides a magnetron
sputtering apparatus that moves a plasma loop as time passes and
prevents a local abrasion of a target to achieve uniform
consumption thereof, thereby increasing a lifetime of the
target.
[0021] Moreover, the present invention also provides a magnetron
sputtering apparatus having a magnet rotating mechanism and a long
lifetime without imposing a great burden on a rotation device or a
column-shaped rotation shaft.
Means for Solving the Problems
[0022] In accordance with a first aspect of the present invention,
there is provided a magnetron sputtering apparatus that includes a
substrate to be processed, a target installed to face the substrate
and a magnet installed at a side opposite to the substrate across
the target, and confines plasma on a surface of the target by
forming a magnetic field on the target surface by the magnet. The
magnet includes a rotary magnet body installed around a
column-shaped rotation shaft in a spiral shape and a stationary
outer peripheral body installed in the vicinity of the rotary
magnet body in parallel to the target surface. The stationary outer
peripheral body is made of a magnet magnetized in a direction
perpendicular to the target surface or a ferromagnetic body which
is not previously magnetized. The rotary magnet body rotates with
the column-shaped rotation shaft, so that a pattern of the magnetic
field on the target surface moves as time passes, and a torque
applied to the column-shaped rotation shaft due to an interaction
between the rotary magnet body and the stationary outer peripheral
body is in a range of about 0.1 Nm to 1 Nm.
[0023] In accordance with a second aspect of the present invention,
there is provided a magnetron sputtering apparatus that includes a
substrate to be processed, a target installed to face the substrate
and a magnet installed at a side opposite to the substrate across
the target, and confines plasma on a surface of the target by
forming a magnetic field on the target surface by the magnet. The
magnet includes a rotary magnet body installed around a
column-shaped rotation shaft in a spiral shape and a stationary
outer peripheral body installed in the vicinity of the rotary
magnet body in parallel to the target surface. The stationary outer
peripheral body is made of a magnet magnetized in a direction
perpendicular to the target surface or a ferromagnetic body which
is not previously magnetized. The rotary magnet body rotates with
the column-shaped rotation shaft, so that a pattern of the magnetic
field on the target surface moves as time passes. A torque applied
to the column-shaped rotation shaft due to an interaction between
the rotary magnet body and the stationary outer peripheral body is
in a range of about 0.1 Nm to 1 Nm, and a force applied to the
column-shaped rotation shaft in one direction is in a range of
about 1 N to 300 N.
[0024] In accordance with a third aspect of the present invention,
there is provided a magnetron sputtering apparatus that includes a
substrate to be processed, a target installed to face the substrate
and a magnet installed at a side opposite to the substrate across
the target, and confines plasma on a surface of the target by
forming a magnetic field on the target surface by the magnet. The
magnet includes a rotary magnet body installed around a
column-shaped rotation shaft in a spiral shape and a stationary
outer peripheral body installed in the vicinity of the rotary
magnet body in parallel to the target surface. The stationary outer
peripheral body is made of a magnet magnetized in a direction
perpendicular to the target surface or a ferromagnetic body which
is not previously magnetized. The rotary magnet body rotates with
the column-shaped rotation shaft, so that a pattern of the magnetic
field on the target surface moves as time passes, and a torque
applied to the column-shaped rotation shaft due to an interaction
between the rotary magnet body and the stationary outer peripheral
body is in a range of about 0.1 Nm to 10 Nm.
[0025] In accordance with a fourth aspect of the present invention,
there is provided a magnetron sputtering apparatus that includes a
substrate to be processed, a target installed to face the substrate
and a magnet installed at a side opposite to the substrate across
the target, and confines plasma on a surface of the target by
forming a magnetic field on the target surface by the magnet. The
magnet includes a rotary magnet body installed around a
column-shaped rotation shaft in a spiral shape and a stationary
outer peripheral body installed in the vicinity of the rotary
magnet body in parallel to the target surface. The stationary outer
peripheral body is made of a magnet magnetized in a direction
perpendicular to the target surface or a ferromagnetic body which
is not previously magnetized. The rotary magnet body rotates with
the column-shaped rotation shaft, so that a pattern of the magnetic
field on the target surface moves as time passes, and a torque
applied to the column-shaped rotation shaft due to an interaction
between the rotary magnet body and the stationary outer peripheral
body is in a range of about 0.1 Nm to 100 Nm.
[0026] In accordance with a fifth aspect of the present invention,
there is provided a magnetron sputtering apparatus that includes a
substrate to be processed, a target installed to face the substrate
and a magnet installed at a side opposite to the substrate across
the target, and confines plasma on a surface of the target by
forming a magnetic field on the target surface by the magnet. A
plurality of plasma loops is formed on the target surface.
[0027] In accordance with a sixth aspect of the present invention,
there is provided a magnetron sputtering apparatus that includes a
substrate to be processed, a target installed to face the substrate
and a magnet installed at a side opposite to the substrate across
the target, and confines plasma on a surface of the target by
forming a magnetic field on the target surface by the magnet. A
plurality of plasma loops is formed on the target surface, and the
plurality of plasma loops moves as the magnet moves.
[0028] In accordance with a seventh aspect of the present
invention, there is provided a magnetron sputtering apparatus that
includes a substrate to be processed, a target installed to face
the substrate and a magnet installed at a side opposite to the
substrate across the target, and confines plasma on a surface of
the target by forming a magnetic field on the target surface by the
magnet. A plasma loop formed on the target surface is repeatedly
generated, moves and disappears as the magnet moves.
[0029] In accordance with an eighth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the fifth aspect to the seventh aspect,
wherein the magnet may include a rotary magnet body installed
around a column-shaped rotation shaft in a spiral shape and a
stationary outer peripheral body installed in the vicinity of the
rotary magnet body in parallel to the target surface. The
stationary outer peripheral body may be made of a magnet magnetized
in a direction perpendicular to the target surface or a
ferromagnetic body which is not previously magnetized. The rotary
magnet body may rotate with the column-shaped rotation shaft, so
that the plasma loop is generated, moves, and disappears.
[0030] In accordance with a ninth aspect of the present invention,
there is provided a magnetron sputtering apparatus that includes a
substrate to be processed, a target installed to face the substrate
and a magnet installed at a side opposite to the substrate across
the target, and confines plasma on a surface of the target by
forming a magnetic field on the target surface by the magnet. On
the target surface, a plasma loop is formed around a region on a
loop where a vertical magnetic field component perpendicular to the
target does not substantially exist while a horizontal magnetic
field component parallel to the target mainly exists, and the
horizontal magnetic field component at all position on the loop
where the horizontal magnetic field mainly exists is in a range of
about 500 Gauss to 1200 Gauss.
[0031] In accordance with a tenth aspect of the present invention,
there is provided a magnetron sputtering apparatus that includes a
substrate to be processed, a target installed to face the substrate
and a magnet installed at a side opposite to the substrate across
the target, and confines plasma on a surface of the target by
forming a magnetic field on the target surface by the magnet. On
the target surface, a plasma loop is formed around a region on a
loop where a vertical magnetic field component perpendicular to the
target does not substantially exist while a horizontal magnetic
field component parallel to the target mainly exists, and the
horizontal magnetic field component at all position on the loop
where the horizontal magnetic field mainly exists is in a range of
about 500 Gauss to 750 Gauss.
[0032] In accordance with an eleventh aspect of the present
invention, there is provided a magnetron sputtering apparatus that
includes a substrate to be processed, a target installed to face
the substrate and a magnet installed at a side opposite to the
substrate across the target, and confines plasma on a surface of
the target by forming a magnetic field on the target surface by the
magnet. On the target surface, a plasma loop is formed around a
region on a loop where a vertical magnetic field component
perpendicular to the target does not substantially exist while a
horizontal magnetic field component parallel to the target mainly
exists, and the horizontal magnetic field component at all position
on the loop where the horizontal magnetic field mainly exists has a
minimum value in a range of about 25% to 65% of a maximum
value.
[0033] In accordance with a twelfth aspect of the present
invention, there is provided a magnetron sputtering apparatus that
includes a substrate to be processed, a target installed to face
the substrate and a magnet installed at a side opposite to the
substrate across the target, and confines plasma on a surface of
the target by forming a magnetic field on the target surface by the
magnet. On the target surface, a plasma loop is formed around a
region on a loop where a vertical magnetic field component
perpendicular to the target does not substantially exist while a
horizontal magnetic field component parallel to the target mainly
exists, and the horizontal magnetic field component at all position
on the loop where the horizontal magnetic field mainly exists has a
minimum value in a range of about 65% to 100% of a maximum
value.
[0034] In accordance with a thirteenth aspect of the present
invention, there is provided a magnetron sputtering apparatus that
includes a substrate to be processed, a target installed to face
the substrate and a magnet installed at a side opposite to the
substrate across the target, and confines plasma on a surface of
the target by forming a magnetic field on the target surface by the
magnet. On the target surface, a plasma loop is formed around a
region on a loop where a vertical magnetic field component
perpendicular to the target does not substantially exist while a
horizontal magnetic field component parallel to the target mainly
exists, and the horizontal magnetic field component at all position
on the loop where the horizontal magnetic field mainly exists has a
minimum value in a range of about 75% to 100% of a maximum
value.
[0035] In accordance with a fourteenth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the ninth aspect to the thirteenth aspect,
wherein the magnet may include a rotary magnet body installed
around a column-shaped rotation shaft in a spiral shape; and a
stationary outer peripheral body installed in the vicinity of the
rotary magnet body in parallel to the target surface. The
stationary outer peripheral body may be made of a magnet magnetized
in a direction perpendicular to the target surface or a
ferromagnetic body which is not previously magnetized. The rotary
magnet body may rotate with the column-shaped rotation shaft, so
that the plasma loop is generated, moves, and disappears.
[0036] In accordance with a fifteenth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the first aspect to the fourth aspect or
any one of the eighth aspect to the fourteenth aspect, wherein the
rotary magnet body may include a plurality of spiral bodies formed
around the column-shaped rotation shaft, and form a spiral-shaped
magnet set in which adjacent spiral bodies in an axial direction of
the column-shaped rotation shaft have opposite magnetic poles of an
N pole and an S pole on an outer side of the column-shaped rotation
shaft in its diametrical direction. The stationary outer peripheral
body may be configured to surround the rotary magnet body when
viewed from the target, and may form magnetic poles of an N pole or
an S pole on a side of the target or it may be not previously
magnetized.
[0037] In accordance with a sixteenth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the fifteenth aspect, wherein when the column-shaped
rotation shaft and the rotary magnet body are viewed from a
direction perpendicular to an axis of the column-shaped rotation
shaft, an acute angle between a direction of the magnet forming a
spiral and an axial direction of the column-shaped rotation shaft
may be in a range of about 35.degree. to 50.degree..
[0038] In accordance with a seventeenth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the fifteenth aspect, wherein when the column-shaped
rotation shaft and the rotary magnet body are viewed from a
direction perpendicular to an axis of the column-shaped rotation
shaft, an acute angle between a direction of the magnet forming a
spiral and an axial direction of the column-shaped rotation shaft
may be in a range of about 30.degree. to 70.degree..
[0039] In accordance with an eighteenth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the fifteenth aspect, wherein when the column-shaped
rotation shaft and the rotary magnet body are viewed from a
direction perpendicular to an axis of the column-shaped rotation
shaft, an acute angle between a direction of the magnet forming a
spiral and an axial direction of the column-shaped rotation shaft
may be in a range of about 70.degree. to 88.degree..
[0040] In accordance with a nineteenth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the fifteenth aspect, wherein when the column-shaped
rotation shaft and the rotary magnet body are viewed from a
direction perpendicular to an axis of the column-shaped rotation
shaft, an acute angle between a direction of the magnet forming a
spiral and an axial direction of the column-shaped rotation shaft
may be in a range of about 75.degree. to 85.degree..
[0041] In accordance with a twentieth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the fifteenth aspect to the nineteenth
aspect, wherein the rotary magnet body may be a spiral-shaped plate
magnet set having plate magnets installed on the column-shaped
rotation shaft in a spiral shape to form 2 spirals, and adjacent
spirals in an axial direction of the column-shaped rotation shaft
may have opposite magnetic poles of an N pole and an S pole on the
outer side of the column-shaped rotation shaft in its diametrical
direction.
[0042] In accordance with a twenty first aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the fifteenth aspect to the nineteenth
aspect, wherein the rotary magnet body may be a spiral-shaped plate
magnet set having plate magnets installed on the column-shaped
rotation shaft in a spiral shape to form 4, 6, 8 or 10 spirals, and
adjacent spirals in an axial direction of the column-shaped
rotation shaft may have opposite magnetic poles of an N pole and an
S pole on the outer side of the column-shaped rotation shaft in its
diametrical direction.
[0043] In accordance with a twenty second aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the fifteenth aspect to the twenty first
aspect, wherein a magnet, which freely moves independently of the
rotary magnet body and the stationary outer peripheral body, may be
installed in the vicinity of the rotary magnet body.
[0044] In accordance with a twenty third aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the twenty second aspect, wherein the magnet, which
freely moves independently of the rotary magnet body and the
stationary outer peripheral body, may be installed in the vicinity
of the rotary magnet body, and when the column-shaped rotation
shaft is rotated, a torque and a force applied to the column-shaped
rotation shaft due to the interaction between the rotary magnet
body and the stationary outer peripheral body are always smaller
than those in a case where no magnet that freely moves may be
provided.
[0045] In accordance with a twenty fourth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the twentieth aspect to the twenty third
aspect, wherein at least a part of the column-shaped rotation shaft
may be made of a paramagnetic body.
[0046] In accordance with a twenty fifth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the twentieth aspect to the twenty fourth
aspect, wherein the column-shaped rotation shaft may be made of a
magnetic body having a hollow structure, and a thickness thereof
may be set such that a magnetic flux density at an entire region in
the magnetic body becomes equal to or less than about 65% of a
saturated magnetic flux density of the magnetic body.
[0047] In accordance with a twenty sixth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the twentieth aspect to the twenty fifth
aspect, wherein the column-shaped rotation shaft may be made of a
magnetic body having a hollow structure, and a thickness thereof
may be set such that a magnetic flux density at an entire region in
the magnetic body becomes equal to or less than about 60% of a
saturated magnetic flux density of the magnetic body and smaller
than a residual magnetic flux density of the magnet forming the
rotary magnet body.
[0048] In accordance with a twenty seventh aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the twentieth aspect to the twenty sixth
aspect, wherein the column-shaped rotation shaft may be made of a
magnetic body having a hollow structure, and a thickness thereof
may be set such that a magnetic flux density at an entire region in
the magnetic body becomes smaller than a residual magnetic flux
density of the magnet forming the rotary magnet body.
[0049] In accordance with a twenty eighth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the twentieth aspect to the twenty seventh
aspect, wherein a stationary outer peripheral paramagnetic body may
be installed adjacent to the stationary outer peripheral body at a
surface opposite to the target across the stationary outer
peripheral body.
[0050] In accordance with a twenty ninth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the twentieth aspect to the twenty eighth
aspect, wherein a unit that allows a magnetic flux starting from
the stationary outer peripheral body to an outside of the target to
be weaker than a magnetic flux starting from the stationary outer
peripheral body to an inside of the target may be provided.
[0051] In accordance with a thirtieth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the twentieth aspect to the twenty ninth
aspect, wherein the unit may include a paramagnetic member
installed to continuously cover an outer lateral surface of the
stationary outer peripheral body when viewed from the target and a
part of a target-side surface thereof.
[0052] In accordance with a thirty first aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the twentieth aspect to the thirtieth
aspect, wherein the rotary magnet body and the stationary outer
peripheral body may be movable in a direction perpendicular to the
target surface.
[0053] In accordance with a thirty second aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the twentieth aspect to the thirty first
aspect, wherein the rotary magnet body and the stationary outer
peripheral body may be installed in a space surrounded by a target
member, a backing plate to which the target member is fixed, and a
wall extended from the vicinity of the backing plate, and the space
may be capable of being depressurized.
[0054] In accordance with a thirty third aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the thirty second aspect, wherein a thickness of the
backing plate may be thinner than an initial thickness of the
target.
[0055] In accordance with a thirty fourth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the twentieth aspect to the thirty third
aspect, wherein a unit that relatively moves the substrate in a
direction intersecting with the axial direction of the
column-shaped rotation shaft may be provided.
[0056] In accordance with a thirty fifth aspect of the present
invention, there is provided a magnetron sputtering apparatus
including a plurality of magnetron sputtering apparatuses as
described in any one of the twentieth aspect to the thirty fourth
aspect provided in parallel to each other in an axial direction of
the column-shaped rotation shaft and a unit that relatively moves
the substrate in a direction intersecting with the axial direction
of the column-shaped rotation shaft.
[0057] In accordance with a thirty sixth aspect of the present
invention, there is provided a magnetron sputtering apparatus
including a plurality of the magnetron sputtering apparatuses as
described in any one of the twentieth aspect to the thirty fourth
aspect and a unit that relatively moves the substrate in a
direction intersecting with the axial direction of the
column-shaped rotation shaft. Each magnetron sputtering apparatus
has a target material different to each other, and is provided in
parallel to each other in an axial direction of the column-shaped
rotation shaft.
[0058] In accordance with a thirty seventh aspect of the present
invention, there is provided a magnetron sputtering apparatus that
includes a substrate to be processed, a target installed to face
the substrate and a magnet installed at a side opposite to the
substrate across the target, and confines plasma on a surface of
the target by forming a magnetic field on the target surface by the
magnet. A plurality of plasma loops is formed on the target
surface, a distance between the target surface and a surface of the
substrate is set to be equal to or less than about 30 mm, and a
magnetic field on the substrate surface is set to be equal to or
less than about 100 Gauss.
[0059] In accordance with a thirty eighth aspect of the present
invention, there is provided a magnetron sputtering apparatus that
includes a substrate to be processed, a target installed to face
the substrate and a magnet installed at a side opposite to the
substrate across the target, and confines plasma on a surface of
the target by forming a magnetic field on the target surface by the
magnet. A plurality of plasma loops is formed on the target
surface, a distance between the target surface and a surface of the
substrate is set to be equal to or less than about 30 mm, and a
magnetic field on the substrate surface is set to be equal to or
less than about 20 Gauss.
[0060] In accordance with a thirty ninth aspect of the present
invention, there is provided a magnetron sputtering apparatus that
includes a substrate to be processed, a target installed to face
the substrate, a target holding unit installed at a side opposite
to the substrate across the target and a magnet installed to face
the target via the target holding unit, and confines plasma on a
surface of the target by forming a magnetic field on the target
surface by the magnet. A plurality of plasma loops is formed on the
target surface, and a thickness of the target holding unit is set
to be equal to or less than about 30% of an initial thickness of
the target.
[0061] In accordance with a fortieth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the thirty ninth aspect, wherein a first space between
the substrate and the target may be capable of being depressurized,
a second space between the target holding unit and the magnet may
be capable of being depressurized, and a pressure in the first
space may be substantially the same as that in the second
space.
[0062] In accordance with a forty first aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the fortieth aspect, wherein a thickness of the
backing plate may be thinner than an initial thickness of the
target.
[0063] In accordance with a forty second aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the thirty ninth aspect to the forty first
aspect, wherein a cooling unit may be installed at the target
holding unit.
[0064] In accordance with a forty third aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the forty second aspect, wherein the cooling unit may
be installed in the second space and may be positioned close to
both end portions of the target holding unit.
[0065] In accordance with a forty fourth aspect of the present
invention, there is provided a magnetron sputtering apparatus that
includes a substrate to be processed, a target installed to face
the substrate and a magnet installed at a side opposite to the
substrate across the target, and confines plasma on a surface of
the target by forming a magnetic field on the target surface by the
magnet. The magnet includes a rotary magnet body installed around a
column-shaped rotation shaft in a spiral shape and a stationary
outer peripheral body installed in the vicinity of the rotary
magnet body in parallel to the target surface. The stationary outer
peripheral body is made of a magnet magnetized in a direction
perpendicular to the target surface or a ferromagnetic body which
is not previously magnetized. The rotary magnet body rotates with
the column-shaped rotation shaft, so that a pattern of the magnetic
field on the target surface moves as time passes. The target is
fixed to a backing plate made of a metal, and the rotary magnet
body is surrounded by a metal plate electrically connected with the
backing plate. A mechanism that applies at least a high frequency
power as a plasma excitation power to the target via the metal
plate is Provided, and the high frequency power has a single
frequency or a plurality of frequencies. A plurality of power feed
points is arranged in a direction of the rotation shaft at a pitch
shorter than a distance of about 1/10 of a half-wavelength of the
highest frequency of the high frequency power in a vacuum.
[0066] In accordance with a forty fifth aspect of the present
invention, there is provided a magnetron sputtering apparatus that
includes a substrate to be processed, a target installed to face
the substrate and a magnet installed at a side opposite to the
substrate across the target, and confines plasma on a surface of
the target by forming a magnetic field on the target surface by the
magnet. The magnet includes a rotary magnet body installed around a
column-shaped rotation shaft in a spiral shape and a stationary
outer peripheral body installed in the vicinity of the rotary
magnet body in parallel to the target surface. The stationary outer
peripheral body is made of a magnet magnetized in a direction
perpendicular to the target surface or a ferromagnetic body which
is not previously magnetized. The rotary magnet body rotates with
the column-shaped rotation shaft, so that a pattern of the magnetic
field on the target surface moves as time passes, and a mechanism
for generating a magnetic field at a side opposite to the target
across the substrate is provided.
[0067] In accordance with a forty sixth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the forty fifth aspect, wherein a mounting table that
mounts thereon the substrate may be installed at a side opposite to
the target across the substrate, and the mechanism for generating
the magnetic field may be a magnet installed in the mounting
table.
[0068] In accordance with a forty seventh aspect of the present
invention, there is provided magnetron sputtering apparatus that
includes a substrate to be processed, a target installed to face
the substrate and a magnet installed at a side opposite to the
substrate across the target, and confines plasma on a surface of
the target by forming a magnetic field on the target surface by the
magnet. The magnet includes a rotary magnet body installed around a
column-shaped rotation shaft in a spiral shape and a stationary
outer peripheral body installed in the vicinity of the rotary
magnet body in parallel to the target surface. The stationary outer
peripheral body is made of a ferromagnetic body. The rotary magnet
body rotates with the column-shaped rotation shaft, so that a
pattern of the magnetic field on the target surface moves as time
passes.
[0069] In accordance with a forty eighth aspect of the present
invention, there is provided a magnetron sputtering apparatus that
includes a substrate to be processed, a target installed to face
the substrate and a magnet installed at a side opposite to the
substrate across the target, and confines plasma on a surface of
the target by forming a magnetic field on the target surface by the
magnet. The magnet includes a rotary magnet body installed around a
column-shaped rotation shaft in a spiral shape; and a stationary
outer peripheral body installed in the vicinity of the rotary
magnet body in parallel to the target surface. The stationary outer
peripheral body is made of a magnet magnetized in a direction
perpendicular to the target surface or a ferromagnetic body which
is not previously magnetized. The rotary magnet body includes a
first spiral body formed by installing a magnet, which is
magnetized such that its surface becomes an S pole or an N pole, at
the column-shaped rotation shaft in a spiral shape and a second
spiral body formed by installing a ferromagnetic body, which is not
previously magnetized, at the column-shaped rotation shaft in a
spiral shape to be adjacent to and in parallel to the first spiral
body. The rotary magnet body rotates with the column-shaped
rotation shaft, so that a pattern of the magnetic field on the
target surface moves as time passes.
[0070] In accordance with a forty ninth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the forty seventh aspect or the forty eighth aspect,
wherein the rotary magnet body may be configured to have a magnet
structure featuring a target use efficiency equal to or higher than
about 80%, which is determined by a target consumption distribution
determined based on a Larmor radius of electrons confined in the
horizontal magnetic field and a curvature radius of the magnetic
field.
[0071] In accordance with a fiftieth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the forty ninth aspect, wherein the target consumption
distribution may be determined by an erosion half-width which is
determined based on the Larmor radius and the curvature radius of
the magnetic field.
[0072] In accordance with a fifty first aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the fiftieth aspect, wherein the Larmor radius may be
determined by using the following formula (1):
[ Eq . 1 ] r c = 34 V D C ( V ) B ( Gauss ) ( mm ) ( 1 )
##EQU00001##
[0073] Here, r.sub.c is a Larmor radius, B is a magnetic flux
density, and V.sub.DC is a self-bias voltage.
[0074] In accordance with a fifty second aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the fiftieth aspect or the fifty first, wherein the
erosion half-width is determined by using the following formula
(2):
W.apprxeq.2 {square root over (2Rr.sub.c)}(mm) (2)
[0075] Here, W is an erosion half-width and R is a curvature radius
of the magnetic field.
[0076] In accordance with a fifty third aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the fiftieth aspect to the fifty second
aspect, wherein the target consumption distribution may be
determined based on a phase average of the erosion half-width when
the rotary magnet body is rotated.
[0077] In accordance with a fifty fourth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the forty ninth aspect to the fifty third
aspect, wherein the target use efficiency may be determined such
that the target consumption distribution is substantially uniform
across an entire surface of the target.
[0078] In accordance with a fifty fifth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the forty ninth aspect to the fifty fourth
aspect, wherein the rotary magnet body may include a plate magnet
set having a plurality of plate magnets installed on the
column-shaped rotation shaft to form a plurality of spirals, and,
in the magnet structure, a distance between the adjacent plate
magnets of the plate magnet set may be set such that the target use
efficiency is equal to or higher than about 80%.
[0079] In accordance with a fifty sixth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the forty ninth aspect to the fifty fifth
aspect, wherein the rotary magnet body may include a plate magnet
set having a plurality of plate magnets installed on the
column-shaped rotation shaft in a spiral shape, and in the magnet
structure, a thickness of the plate magnet may be set such that the
target use efficiency is equal to or higher than about 80%.
[0080] In accordance with a fifty seventh aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the forty ninth aspect to the fifty sixth
aspect, wherein the rotary magnet body may include a plate magnet
set having a plurality of plate magnets installed on the
column-shaped rotation shaft in a spiral shape, and in the magnet
structure, a width of the plate magnet may be set such that the
target use efficiency is equal to or higher than about 80%.
[0081] In accordance with a fifty eighth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the forty ninth aspect to the fifty seventh
aspect, wherein the rotary magnet body may include a plate magnet
set having a plurality of plate magnets installed on the
column-shaped rotation shaft in a spiral shape while forming a
single loop or multiple loops, and in the magnet structure, the
number of loops may be set such that the target use efficiency is
equal to or higher than about 80%.
[0082] In accordance with a fifty ninth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the forty ninth aspect to the fifty eighth
aspect, wherein the rotary magnet body may include a plate magnet
set having a plurality of plate magnets installed on the
column-shaped rotation shaft in a spiral shape, and in the magnet
structure, an angle formed between an extending direction of the
plate magnets extended in the spiral shape and the axial direction
of the rotation shaft may be set such that the target use
efficiency is equal to or higher than about 80%.
[0083] In accordance with a sixtieth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the fifty ninth aspect, wherein the angle may be in a
range of about 57.degree. to 85.degree..
[0084] In accordance with a sixty first aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the forty ninth aspect to the sixtieth
aspect, wherein the rotary magnet body may include a plate magnet
set including a plate magnet having an N-pole surface installed on
the column-shaped rotation shaft in a spiral shape and a plate
magnet having an S-pole surface installed on the column-shaped
rotation shaft in a spiral shape to be adjacent to the plate magnet
having the N-pole surface, and a width of the plate magnet having
the N-pole surface may be different from a width of the plate
magnet having the S-pole surface.
[0085] In accordance with a sixty second aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the sixty first aspect, wherein the width of the plate
magnet having the N-pole surface may be smaller than the width of
the plate magnet having the S-pole surface.
[0086] In accordance with a sixty third aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the fifty eighth aspect, wherein the number of the
loops may be 1 or 2.
[0087] In accordance with a sixty fourth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the sixtieth aspect, wherein the angle may be equal to
or larger than about 75.degree..
[0088] In accordance with a sixty fifth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the fifty sixth aspect, wherein the thickness may be
in a range of about 5 to 15 mm.
[0089] In accordance with a sixty sixth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the forty eighth aspect, wherein a configuration of
the first spiral body and/or a configuration of the second spiral
body are/is set such that the target use efficiency, which is
expressed by the following formula (3), is equal to or higher than
about 80%:
Target use efficiency.ident.cross sectional area of an erosion
part/An initial cross sectional area of the target (3)
[0090] Here, the target use efficiency is calculated when a minimum
thickness of the target is about 5% of the initial thickness
thereof.
[0091] In accordance with a sixty seventh aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the sixty sixth aspect, wherein a distance between the
first spiral body and the second spiral body may be set such that
the target use efficiency is equal to or higher than about 80%.
[0092] In accordance with a sixty eighth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the sixty seventh aspect, wherein the distance may be
in a range of about 11 to 17 mm.
[0093] In accordance with a sixty ninth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the sixty sixth aspect to the sixty eighth
aspect, wherein plate thicknesses of the first spiral body and the
second spiral body may be set such that the target use efficiency
is equal to or higher than about 80%.
[0094] In accordance with a seventieth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the sixty ninth aspect, wherein the plate thicknesses
may be in a range of about 5 to 15 mm.
[0095] In accordance with a seventy first aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the sixty sixth aspect to the seventieth
aspect, wherein the number of loops of the first spiral body and
the second spiral body may be set such that the target use
efficiency is equal to or higher than about 80%.
[0096] In accordance with a seventy second aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the seventy first aspect, wherein the number of the
loops may be in a range of about 1 to 5.
[0097] In accordance with a seventy third aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the sixty sixth aspect to the seventy
second aspect, wherein widths of the first spiral body and the
second spiral body may be set differently such that the target use
efficiency is equal to or higher than about 80%.
[0098] In accordance with a seventy fourth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the seventy third aspect, wherein, of the first spiral
body and the second spiral body, the width of the spiral body that
forms an N-pole on an outer side in a diametrical direction thereof
may be set to be larger than the width of the spiral body that
forms an S-pole on an outer side in a diametrical direction
thereof.
[0099] In accordance with a seventy fifth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the sixty sixth aspect to the seventy
fourth aspect, wherein an angle between an extending direction of
the first spiral body and the second spiral body and the axial
direction of the rotation shaft may be set such that the target use
efficiency is equal to or higher than about 80%.
[0100] In accordance with a seventy sixth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the seventy fifth aspect, wherein the angle may be in
a range of about 57.degree. to 84.degree..
[0101] In accordance with a seventy seventh aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the seventy fifth aspect, wherein the angle may be in
a range of about 75.degree. to 85.degree..
[0102] In accordance with a seventy eighth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the forty seventh aspect or the forty eighth aspect,
wherein the magnetron sputtering apparatus may further include a
holder configured to mount the substrate; and a backing plate
installed to face the holder so as to hold the target; and a plasma
shielding plate installed between the holder and the backing plate.
The shielding plate may be provided with a slit in a space between
the substrate and the target, and a difference between a width of
the slit and a width of the plasma may be within about 20 mm.
[0103] In accordance with a seventy ninth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the forty seventh aspect or the forty eighth aspect,
wherein the magnetron sputtering apparatus may further include a
holder configured to mount the substrate; and a backing plate
installed to face the holder so as to hold the target; and a plasma
shielding plate installed between the holder and the backing plate.
The shielding plate may be provided with a slit in a space between
the substrate and the target, and a distance between the shielding
plate and the target may be in the range of about 3 to 15 mm.
[0104] In accordance with an eightieth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the forty seventh aspect or the forty eighth aspect,
wherein the magnetron sputtering apparatus may further include a
moving magnet configured to be movable in the apparatus. A strong
magnetic field, generated depending on a rotation coordinate of the
rotary magnet set, may be weakened by moving the moving magnet
along with a rotation of the rotary magnet set.
[0105] In accordance with an eighty first aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the eightieth aspect, wherein the moving magnet may be
movably installed between the rotary magnet set and the peripheral
plate magnet or a stationary outer peripheral ferromagnetic
body.
[0106] In accordance with an eighty second aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the eighty first aspect, wherein the moving magnet may
have a rotation shaft and may be rotatable about the rotation shaft
and may be magnetized in a direction perpendicular to a rotation
direction. The moving magnet may be installed between an end
portion of the column-shaped rotation shaft and the outer
peripheral plate magnet or the stationary outer peripheral
ferromagnetic body such that the rotation shaft of the moving
magnet is perpendicular to the axial direction of the column-shaped
rotation shaft. Further, the moving magnet may be rotated so as to
weaken a magnetic field generated depending on the rotation
coordinate of the rotary magnet set when a polarity of an end
portion of the rotary magnet set becomes the same as a polarity of
a surface of the stationary outer peripheral magnet or the
stationary outer peripheral ferromagnetic body, the surface facing
the end portion.
[0107] In accordance with an eighty third aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the eighty first aspect, wherein the moving magnet may
have a rotation shaft parallel to a rotation axis of the rotary
magnet set between a lateral surface of the column-shaped rotation
shaft and the stationary outer peripheral plate magnet or the
stationary outer peripheral ferromagnetic body, and may be
rotatable about the rotation shaft and may be magnetized in a
direction perpendicular to a rotation direction. Further, the
moving magnet may be rotated so as to weaken a magnetic field
generated depending on the rotation coordinate of the rotary magnet
set when a polarity of a part of lateral surface of the rotary
magnet set becomes the same as a polarity of a surface of the
stationary outer peripheral magnet or the stationary outer
peripheral ferromagnetic body, the lateral surface facing the
surface.
[0108] In accordance with an eighty fourth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the eighty first aspect to the eighty third
aspect, wherein the moving magnet may be installed between a
lateral surface of the column-shaped rotation shaft and the outer
peripheral plate magnet or the stationary outer peripheral
ferromagnetic body to be movable in a direction parallel to a
rotation axis of the rotary magnet set. Further, the moving magnet
may be moved in the direction perpendicular to the rotation axis of
the rotary magnet set so as to weaken a magnetic field generated
depending on the rotation coordinate of the rotary magnet set when
a polarity of a part of lateral surface of the rotary magnet set
becomes the same as a polarity of a part of lateral surface of the
stationary outer peripheral magnet or the stationary outer
peripheral ferromagnetic body, the lateral surface facing the
surface.
[0109] In accordance with an eighty fifth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the eighty first aspect to the eighty
fourth aspect, wherein the moving magnet may be a rotary magnet
configured to be freely rotated.
[0110] In accordance with an eighty sixth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the eightieth aspect to the eighty fifth
aspect, wherein a surface of the moving magnet may be covered with
a non-magnetic substance.
[0111] In accordance with an eighty seventh aspect of the present
invention, there is provided a magnetic field control method of a
magnetron sputtering apparatus as described in any one of the
eightieth aspect to the eighty sixth aspect, the method including:
when, depending on a rotation coordinate of the rotary magnet set,
a polarity of a facing surface of the rotary magnet set becomes the
same as a polarity of a facing surface of the stationary outer
peripheral magnet or the stationary outer peripheral ferromagnetic
body, moving the moving magnet such that its polarity opposite to
the polarity of the facing surfaces faces toward the facing
surfaces.
[0112] In accordance with an eighty eighth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the forty seventh aspect or the forty eighth aspect,
wherein the magnetron sputtering apparatus may further include a
collimator configured to allow travelling directions of sputtered
target particles to be uniform.
[0113] In accordance with an eighty ninth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the eighty eighth aspect, wherein the collimator may
be installed between the substrate and the target, and the
travelling direction of the sputtered target particles may be
allowed to be coincident with a thickness direction of a film to be
formed.
[0114] In accordance with a ninetieth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the eighty ninth aspect, wherein the collimator may be
fixed to be adjacent to the target.
[0115] In accordance with a ninety first aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the eighty ninth aspect, wherein the collimator may be
configured to be movable according to a movement of the
substrate.
[0116] In accordance with a ninety second aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the eighty eighth aspect to the ninety
first aspect, wherein the magnet may include a rotary magnet set
having a plurality of plate magnets installed on the column-shaped
rotation shaft in a spiral shape to be rotatable and a stationary
outer peripheral plate magnet installed in the vicinity of the
rotary magnet set in parallel to the surface of the target and
magnetized in a direction perpendicular to the surface of the
target.
[0117] In accordance with a ninety third aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the eighty eighth aspect to the ninety
second aspect, wherein the collimator may be made of at least one
of Ti, Ta, Al, and stainless steel.
[0118] In accordance with a ninety fourth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the eighty eighth aspect to the ninety
third aspect, wherein the magnetron sputtering apparatus may
further include a removing unit which removes sputtered particles
of the target material adhered to the collimator.
[0119] In accordance with a ninety fifth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in the ninety fourth aspect, wherein the removing unit
may remove the sputtered particles of the adhered target material
by applying a voltage to the collimator.
[0120] In accordance with a ninety sixth aspect of the present
invention, there is provided a target collimation apparatus
installed in a magnetron sputtering apparatus as described in the
forty seventh aspect or the forty eighth aspect and configured to
allow travelling directions of sputtered target particles to be
uniformed, the apparatus including: a collimator configured to
allow the travelling direction of the sputtered target particles to
be uniformed.
[0121] In accordance with a ninety seventh aspect of the present
invention, there is provided a target collimation apparatus as
described in the ninety sixth aspect, wherein the collimator may be
made of at least one of Ti, Ta, Al, and stainless steel.
[0122] In accordance with a ninety eighth aspect of the present
invention, there is provided a target collimation apparatus as
described in the ninety seventh aspect, wherein the target
collimation apparatus may further include a removing unit which
removes sputtered particles of the target material adhered to the
collimator.
[0123] In accordance with a ninety ninth aspect of the present
invention, there is provided a target collimation apparatus as
described in the ninety eighth aspect, wherein the removing unit
may remove sputtered particles of the target material by applying a
voltage to the collimator.
[0124] In accordance with a hundredth aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the forty fourth aspect to the eighty sixth
aspect and the eighty eighth aspect to the ninety ninth aspect,
wherein the rotary magnet body and the stationary outer peripheral
body may be movable in the direction perpendicular to the surface
of the target.
[0125] In accordance with a hundred first aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the forty fourth aspect to the eighty sixth
aspect and the eighty eighth aspect to the hundredth aspect,
wherein the rotary magnet body and the stationary outer peripheral
body may be installed in a space surrounded by a target member, a
backing plate to which the target member is fixed, and a wall
extended from the vicinity of the backing plate, and the space may
be capable of being depressurized.
[0126] In accordance with a hundred second aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the forty fourth aspect to the eighty sixth
aspect and the eighty eighth aspect to the hundred first aspect,
wherein the target may be fixed to a backing plate and a thickness
of the backing plate may be thinner than an initial thickness of
the target.
[0127] In accordance with a hundred third aspect of the present
invention, there is provided a magnetron sputtering apparatus as
described in any one of the fortieth aspect to the eighty sixth
aspect and the eighty eighth aspect to the hundred second aspect,
wherein a unit that relatively moves the substrate in a direction
intersecting with the axial direction of the column-shaped rotation
shaft may be provided.
[0128] In accordance with a hundred fourth aspect of the present
invention, there is provided a magnetron sputtering apparatus
including a plurality of magnetron sputtering apparatuses as
described in any one of the fortieth aspect to the eighty sixth
aspect and the eighty eighth aspect to the hundred second aspect
provided in parallel to each other in an axial direction of the
column-shaped rotation shaft and a unit that relatively moves the
substrate in a direction intersecting with the axial direction of
the column-shaped rotation shaft.
[0129] In accordance with a hundred fifth aspect of the present
invention, there is provided a magnetron sputtering apparatus
including a plurality of the magnetron sputtering apparatuses as
described in any one of the fortieth aspect to the eighty sixth
aspect and the eighty eighth aspect to the hundred second aspect
and a unit that relatively moves the substrate in a direction
intersecting with the axial direction of the column-shaped rotation
shaft. Each magnetron sputtering apparatus has a target material
different to each other, and is provided in parallel to each other
in an axial direction of the column-shaped rotation shaft.
[0130] In accordance with a hundred sixth aspect of the present
invention, there is provided a magnetron sputtering method for
depositing a material of the target on a substrate to be processed
while rotating the column-shaped rotation shaft by using a
magnetron sputtering apparatus as described in any one of the first
aspect to the eighty sixth aspect and the eighty eighth aspect to
the hundred fifth aspect.
[0131] In accordance with a hundred seventh aspect of the present
invention, there is provided an electronic device manufacturing
method including performing a film formation on a substrate to be
processed by using a sputtering method as described in the hundred
sixth aspect.
[0132] In accordance with a hundred eighth aspect of the present
invention, there is provided a magnetic recording medium
manufacturing method including performing a film formation on a
substrate to be processed by using a sputtering method as described
in the hundred sixth aspect.
[0133] In accordance with a hundred ninth aspect of the present
invention, there is provided a product including a thin film formed
by a sputtering method as described in the hundred sixth
aspect.
Effect of the Invention
[0134] In accordance with the present invention, there is provided
a magnetron sputtering apparatus capable of increasing a film
forming rate and preventing a local abrasion of a target to achieve
uniform consumption thereof, thereby increasing a lifetime of the
target, and also having a magnet rotating mechanism and a long
lifetime without imposing a great burden on a rotation device or a
column-shaped rotation shaft.
BRIEF DESCRIPTION OF THE DRAWINGS
[0135] FIG. 1 is a schematic configuration view of a magnetron
sputtering apparatus in accordance with a first embodiment of the
present invention;
[0136] FIG. 2 is a perspective view describing, in more detail, a
magnet part of the magnetron sputtering apparatus shown in FIG.
1;
[0137] FIG. 3 is a view explaining an erosion formation in the
present invention, wherein S poles are indicated by dots;
[0138] FIG. 4 is a graph showing a relationship between a
horizontal magnetic field strength and a relative magnetic
permeability of a column-shaped rotation shaft used in the
magnetron sputtering apparatus of FIG. 1;
[0139] FIG. 5 is a graph showing a variation of a horizontal
magnetic field strength in a case where a stationary outer
peripheral paramagnetic body, which forms a magnetic circuit with
respect to a stationary outer peripheral plate magnet, is
installed;
[0140] FIG. 6 is a photograph showing a change of plasma on a
surface of a target as time passes;
[0141] FIG. 7 is a photograph showing a state where a target is
consumed for a long period of time;
[0142] FIG. 8A is a diagram for describing a configuration in which
a single spiral-shaped plate magnet set is installed on a
column-shaped rotation shaft and a function thereof; and FIG. 8B is
a diagram for describing a configuration in which a plurality of
spiral-shaped plate magnet sets is installed on the column-shaped
rotation shaft and a function thereof, wherein S poles are
indicated by dots;
[0143] FIG. 9 is a schematic diagram describing a magnetron
sputtering apparatus in accordance with a third embodiment of the
present invention;
[0144] FIG. 10 is a graph showing a relationship between a
thickness of a magnetic body and a maximum magnetic flux density
generated in the magnetic body;
[0145] FIG. 11 is a graph showing a relationship between the number
of spirals of spiral-shaped magnet sets, and a magnetic field
strength, and a spiral angle;
[0146] FIG. 12 illustrates a magnetron sputtering apparatus in
accordance with a second embodiment of the present invention;
[0147] FIG. 13 is a graph showing a relationship between a distance
from a surface of a target and a horizontal magnetic field
strength;
[0148] FIG. 14 illustrates a conventional magnetron sputtering
apparatus;
[0149] FIG. 15A is a schematic configuration view illustrating a
magnetron sputtering apparatus in accordance with a fourth
embodiment of the present invention, and FIG. 15B is a diagram when
viewed from a direction of an arrow X of FIG. 15A;
[0150] FIG. 16 is a schematic configuration view illustrating a
magnetron sputtering apparatus in accordance with a fifth
embodiment of the present invention;
[0151] FIG. 17 is a schematic diagram showing a relationship
between an erosion half-width and a Larmor radius;
[0152] FIG. 18 is a graph showing a comparison between an actual
measurement value and a calculation value of an erosion
distribution on a surface of a target in a sixth embodiment of the
present invention;
[0153] FIG. 19 is a schematic diagram illustrating sizes of a
column-shaped rotation shaft 2 and a spiral-shaped plate magnet set
3 in the sixth embodiment of the present invention;
[0154] FIG. 20 is a schematic diagram illustrating sizes of the
column-shaped rotation shaft 2 and the spiral-shaped plate magnet
set 3 in the sixth embodiment of the present invention;
[0155] FIGS. 21A and 21B are cross sectional views of a surface of
a target 1 perpendicular to a rotation axis of the column-shaped
rotation shaft 2 in the sixth embodiment of the present invention,
wherein FIG. 21A shows the target 1 before it is used and FIG. 21B
shows the target 1 after it is used (consumed);
[0156] FIG. 22 is a plane view showing a shape of the spiral-shaped
plate magnet set 3 in respective cases that a distance between
magnets is about 8 mm, 12 mm and 17 mm in the sixth embodiment of
the present invention;
[0157] FIG. 23 is a diagram showing an erosion distribution when a
distance between magnets of the spiral-shaped plate magnet set 3 is
varied in the sixth embodiment of the present invention;
[0158] FIG. 24 is a diagram showing a relationship between a
distance between magnets, a use efficiency and a horizontal
magnetic field in the sixth embodiment of the present
invention;
[0159] FIG. 25 is a diagram showing a relationship between a plate
thickness tm and a consumption distribution in the sixth embodiment
of the present invention;
[0160] FIG. 26 is a diagram showing a relationship between a plate
thickness tm and a use efficiency in the sixth embodiment of the
present invention;
[0161] FIG. 27 is a plane view showing a relationship between the
number (m) of loops and an angle (.alpha.) of the spiral-shaped
plate magnet set 3 in the sixth embodiment of the present
invention;
[0162] FIG. 28 is a diagram showing a relationship between the
number m of loops of the spiral-shaped plate magnet set 3 and a
consumption distribution in the sixth embodiment of the present
invention;
[0163] FIG. 29 is a diagram showing a relationship between the
number (m) of loops, a use efficiency and a magnetic field strength
in the sixth embodiment of the present invention;
[0164] FIG. 30 is a diagram showing a relationship between an angle
(spiral angle) (.alpha.), a use efficiency and a magnetic field
strength;
[0165] FIG. 31 is a diagram viewed from the target in case that an
S-pole magnet width is set to be larger than an N-pole magnet width
in the spiral-shaped plate magnet set 3 in the sixth embodiment of
the present invention;
[0166] FIG. 32 is a diagram showing a relationship between the
S-pole magnet width and a consumption distribution in FIG. 31;
[0167] FIG. 33 is a diagram showing a relationship between a use
efficiency and a horizontal magnetic field strength when the S-pole
and N-pole magnet widths are varied in the sixth embodiment of the
present invention;
[0168] FIG. 34 is a diagram showing an erosion distribution when a
magnet diameter is varied in the sixth embodiment of the present
invention;
[0169] FIG. 35 is a diagram showing a relationship between a plasma
loop width and an erosion width when the magnet diameter is varied
in the sixth embodiment of the present invention;
[0170] FIG. 36 is a diagram showing a positional relationship
between the target 1, a substrate 10 to be processed, a plasma
shield member 16 and a slit 18 in the sixth embodiment of the
present invention;
[0171] FIG. 37 is a diagram showing a width of the slit 18 and a
deposit efficiency when a target-slit distance is varied in the
sixth embodiment of the present invention;
[0172] FIG. 38 depicts a (bottom) perspective view to describe a
magnet part of a magnetron sputtering apparatus in more detail in
accordance with a seventh embodiment of the present invention;
[0173] FIG. 39 is a diagram viewed from a direction of an arrow A2
of FIG. 38;
[0174] FIG. 40 is a schematic configuration view illustrating a
magnetron sputtering apparatus in accordance with an eighth
embodiment of the present invention;
[0175] FIG. 41 presents a perspective view (when viewed from the
bottom) to a magnet part of the magnetron sputtering apparatus
shown in FIG. 40 in more detail;
[0176] FIG. 42 is a diagram viewed from a direction of an arrow A3
of FIG. 41;
[0177] FIG. 43 sets forth a perspective view (viewed from bottom)
describing a magnet part of a magnetron sputtering apparatus in
accordance with a ninth embodiment of the present invention;
[0178] FIG. 44 is a plane view viewed from a direction of an arrow
A4 of FIG. 43;
[0179] FIG. 45 is a schematic configuration view illustrating a
magnetron sputtering apparatus in accordance with a tenth
embodiment of the present invention; and
[0180] FIG. 46 is a schematic configuration view illustrating a
magnetron sputtering apparatus in accordance with an eleventh
embodiment of the present invention.
EXPLANATION OF CODES
[0181] 1: Target
[0182] 2: Column-shaped rotation shaft
[0183] 3: Spiral-shaped rotary magnet sets
[0184] 4: Stationary outer peripheral plate magnet
[0185] 5: Outer peripheral paramagnetic body
[0186] 6: Backing plate
[0187] 8: Coolant passage
[0188] 9: Insulating member
[0189] 10: Target substrate
[0190] 11: Space in chamber
[0191] 12: Feeder line
[0192] 13: Cover
[0193] 14: Outer wall
[0194] 15: Paramagnetic body
[0195] 16: Plasma shield member
[0196] 17: Insulating member
[0197] 18: Slit
[0198] 19: Mounting table
[0199] 20: Space
BEST MODE FOR CARRYING OUT THE INVENTION
[0200] Hereinafter, embodiments of the present invention will be
described with reference to the accompanying drawings.
First Embodiment
[0201] A first embodiment of the present invention will be
explained in detail with reference to the accompanying
drawings.
[0202] FIG. 1 is a cross sectional view illustrating a
configuration of a magnetron sputtering apparatus (rotary magnet
sputtering apparatus) in accordance with the first embodiment of
the present invention.
[0203] In FIG. 1, a reference numeral 1 denotes a target; 2, a
column-shaped rotation shaft; 3, a plurality of plate magnet sets
arranged in a spiral shape on a surface of the rotation shaft 2; 4,
a stationary outer peripheral plate magnet positioned at an outer
periphery; 5, an outer peripheral magnetic body positioned on the
stationary outer peripheral plate magnet 4 to be opposite to the
target; 6, a backing plate to which the target 1 is fixed; 15, a
magnetic body configured to enclose the column-shaped rotation
shaft 2 and the spiral-shaped plate magnet sets 3 except their
target-facing sides; 8, a passage through which a coolant passes;
9, an insulating member; 10, a substrate to be processed; 19, a
mounting table on which the substrate is to be placed; 11, a space
in a processing chamber; 12, a feeder line; 13, a cover
electrically connected with the processing chamber; 14, an outer
wall forming the processing chamber; 16, a plasma shield member
electrically connected with the outer wall 14; 17, an insulating
member having a high plasma resistance; and 18, a slit provided at
the plasma shield member 17.
[0204] A DC power supply, a RF power supply and a matching unit are
connected to the feeder line 12. A power for plasma excitation is
supplied from the DC power supply and the RF power supply to the
backing plate 6 and the target 1 via the matching unit, the feeder
line 12 and a housing, and plasma is excited on a surface of the
target. The plasma excitation may be enabled only by a DC power or
a RF power. Since a plasma density is greatly increased if the RF
power is applied, it may be possible to apply only the RF power to
increase an ion irradiation amount onto the substrate 10 in a film
forming process. Further, in order to increase a film forming rate
as well as the ion irradiation amount, both the RF power and the DC
power can be applied. Meanwhile, the plasma excitation may be
carried out only by the DC power when it is required to decrease
the ion irradiation amount. In this way, a means for the plasma
excitation or a power level may be selected depending on film
forming species or film forming conditions. Further, when the
target 1 made of an insulating material is used, the plasma is
excited by the RF power. Although a frequency of the RF power may
be typically selected within a range of several 100 kHz to several
100 MHz, it is desirable to select a high frequency in order to
obtain high density and low electron temperature plasma. In the
present embodiment, a frequency of about 13.56 MHz is employed.
[0205] The plasma shield member 16 also serves as a ground plate
for the RF power. The ground plate enables efficient plasma
excitation even if the substrate 10 is in an electrically floating
state. The magnetic body 15 has a magnetic shield effect against a
magnetic field generated from magnets and also has an effect of
reducing a variation in the magnetic field due to external factors
in the vicinity of the target.
[0206] To describe the magnet part in more detail, FIG. 2 provides
a perspective view of the column-shaped rotation shaft 2, the
plurality of spiral-shaped plate magnet sets 3 and the stationary
outer peripheral plate magnet 4. Here, the plurality of
spiral-shaped plate magnet sets 3 serves as rotary magnet sets
which are rotated as the column-shaped rotation shaft 2 is
rotated.
[0207] Although the column-shaped rotation shaft 2 may typically be
made of a stainless steel, it may be desirable to form the
column-shaped rotation shaft 2 partially or entirely with a
magnetic material having a low magnetic reluctance, such as a
Ni--Fe-based alloy having a high magnetic permeability or a
Fe-based material. Further, in order to achieve a strong magnetic
flux density on the target surface more efficiently, it is
desirable that a saturated magnetic flux density is great. In the
present embodiment, the column-shaped rotation shaft 2 is
fabricated by using SS400 (having a magnetic permeability equal to
or greater than about 100 and a saturated magnetic flux density of
about 2 T), which is a rolled steel for structures and contains Fe
as a major component. The column-shaped rotation shaft 2 can be
rotated by a gear unit and a motor (not shown).
[0208] The column-shaped rotation shaft 2 has a cross section of a
regular hexadecagon and a length of each side is about 16.7 mm. A
number of rhombus-shaped plate magnets are installed on each
surface of the column-shaped rotation shaft 2, thus forming the
plurality of spiral-shaped plate magnet sets 3. The column-shaped
rotation shaft 2 has a configuration in which the magnets are
installed at its outer periphery, and it can be made thick easily,
and it has a strength enough to endure bending caused by a magnetic
force applied to the magnets.
[0209] Desirably, each plate magnet constituting the spiral-shaped
plate magnet sets 3 has a high residual magnetic flux density, a
high coercive force, and a high energy product, such that a strong
magnetic field is stably generated. For example, a Sm--Co-based
sintered magnet having a residual magnetic flux density of about
1.1 T, more desirably, a Nd--Fe--B-based sintered magnet having a
residual magnetic flux density of about 1.3 T may be employed. In
the present embodiment, a Nd--Fe--B-based sintered magnet is
used.
[0210] Each plate magnet of the spiral-shaped plate magnet sets 3
is magnetized in a direction perpendicular to its plate surface,
and the plate magnets are fixed to the column-shaped rotation shaft
2 in a spiral shape to form a plurality of spirals. The adjacent
spirals in an axial direction of the column-shaped rotation shaft
have opposite magnetic poles, i.e., an N pole and an S pole on
outer sides of the column-shaped rotation shaft in its diametrical
direction.
[0211] When viewed from the target 1, the stationary outer
peripheral plate magnet 4 surrounds the rotary magnet sets made up
of the spiral-shaped plate magnet sets 3, and it is magnetized such
that a side facing the target 1 is an S pole. For the same reason
as each plate magnet of the spiral-shaped plate magnet sets 3, a
Nd--Fe--B-based sintered magnet is used as the stationary outer
peripheral plate magnet 4.
[0212] Further, in order to prevent a temperature rise of the
target, a coolant is circulated through the passage 8 to cool the
target. Additionally or alternatively, cooling units may be
installed in both spaces which are in the vicinity of upper sides
of both ends of the backing plate 6 and below the rotary magnet
sets 3. Moreover, for example, by setting pressures in both spaces
(depressurized) above and below the backing plate and the target to
be substantially same, the backing plate 6 can be set to be thinner
than an initial thickness of the target 1 and, desirably, to be
about equal to or less than about 30% of the initial thickness of
the target.
[0213] Now, referring to FIG. 3, an erosion formation in the
present embodiment will be explained in detail. As stated above, in
case that the spiral-shaped plate magnet sets 3 are formed by
arranging the plurality of plate magnets on the column-shaped
rotation shaft 2, an N pole of the plate magnet is substantially
surrounded by S poles of other plate magnets when the spiral-shaped
plate magnet sets 3 are viewed from the target side. FIG. 3
provides a schematic diagram showing such a configuration. In this
configuration, magnetic force lines start from the N pole of the
plate magnet 3 and end at the surrounding S poles. As a result, a
multitude of closed horizontal magnetic field regions (plasma
loops) 301 are formed on the target surface spaced apart from a
plate magnet surface at a certain distance. Further, the multitude
of plasma loops 301 are moved as the column-shaped rotation shaft 2
is rotated. In FIG. 3, the plasma loops 301 move in a direction
indicated by an arrow. Moreover, the plasma loops 301 are
sequentially generated from one end of the rotary magnet sets 3 and
sequentially disappear at the other end thereof.
[0214] Further, in the present embodiment, although the cross
section of the column-shaped rotation shaft 2 has the regular
hexadecagon shape and the plate magnets are fixed to each surface,
the cross section thereof may have a regular polygonal shape (e.g.,
a regular polygon with 32 sides) having a greater number of sides
and the plate magnets are more densely fastened thereto to obtain a
smoother spiral shape. Alternatively, to cut manufacturing cost, it
may be possible to employ a polygonal shape (e.g., a regular
octagon shape) having a smaller number of sides as long as
horizontal magnetic field loops are formed on the target surface.
Alternatively, in order to make the adjacent plate magnets forming
the spirals become close to each other, a cross section of the
plate magnet may not be a rectangular shape but it may be a
trapezoid shape whose outer side is greater in a diametrical
direction of the rotation shaft.
[0215] Now, referring to FIG. 4, an effect of configuring the
column-shaped rotation shaft 2 as a magnetic body will be
explained.
[0216] In FIG. 4, a vertical axis and a horizontal axis indicate a
horizontal magnetic field strength of the plasma loop 301 and a
relative magnetic permeability of the column-shaped rotation shaft
2, respectively, and the graph shows a dependency of the horizontal
magnetic field strength upon the relative magnetic permeability of
the column-shaped rotation shaft 2. In FIG. 4, it is normalized at
a relative magnetic permeability of 1. As can be seen from FIG. 4,
the horizontal magnetic field strength increases with a rise of the
relative magnetic permeability of the column-shaped rotation shaft
2. Especially, when the relative magnetic permeability is equal to
or greater than 100, an increment of the magnetic field strength is
about 60%. It is because magnetic force lines can be generated on
the target efficiently as a result of reducing a magnetic
reluctance of the plate magnets, which form a spiral, on the side
of the column-shaped rotation shaft. Thus, a plasma confining
effect can be improved when the plasma is excited, and damage
inflicted on the substrate can be reduced due to a reduction of an
electron temperature of the plasma. Furthermore, as a plasma
density increases, a film forming rate can be enhanced.
[0217] Further, as shown in FIG. 5, in a case where the stationary
outer peripheral paramagnetic body 5 is installed below the
stationary outer peripheral plate magnet 4, the horizontal magnetic
field strength is found to be increased by about 10% as compared to
a case where no stationary outer peripheral paramagnetic body 5 is
installed. Further, in a case where a magnetic circuit having a low
magnetic reluctance is formed between the rotary magnet set and the
stationary outer peripheral plate magnet by extending a part of the
stationary outer peripheral paramagnetic body 5 to a portion
adjacent to the column-shaped rotation shaft 2 to be adjacent to
the magnetic body portion of the column-shaped rotation shaft 2 via
ferrofluid, it is found that the horizontal magnetic field strength
is increased by about 30% and a film forming efficiency is
improved.
[0218] The column-shaped rotation shaft 2 is desirably configured
to be light-weighted with a hollow structure so as to suppress its
deformation when the apparatus is scaled-up and to be rotated by a
small torque. Here, it was examined how thin the magnetic body may
be to achieve a magnetic circuit forming effect.
[0219] FIG. 10 shows a relationship between a thickness of the
magnetic body and a maximum magnetic flux density generated in the
magnetic body. A residual magnetic flux density of the
spiral-shaped magnet (Ne--Fe--B-based magnet) is about 1.3 T; a
magnetic permeability of the magnetic body (SS400) is about 100;
and a saturated magnetic flux density is about 2 T.
[0220] The thickness was varied from about 1 mm to 10 mm. As can be
seen from the figure, since the magnetic field in the magnetic body
is almost saturated within the thickness range of about 1 mm to 2
mm, a magnetic circuit forming effect is not shown in this range.
If the thickness is about 4 mm, it is found that the maximum
magnetic flux density in the magnetic body becomes about 1.3 T
which is equivalent to about 65% of a maximum saturated magnetic
flux density, so that the magnetic circuit forming effect is
exhibited. If the thickness is about 6 mm, a magnetic flux density
in the entire region of the magnetic body becomes about 1.2 T or
less, which is equivalent to or less than about 60% of the maximum
saturated magnetic flux density of the magnetic body, so that it
becomes smaller than the residual magnetic flux density of the
magnet. In this case, it is found out that a horizontal magnetic
field on the target surface exceeds about 500 Gauss and such an
effect does not change even if the thickness is further increased.
Thus, by setting a thickness of the magnetic body to be about 6 mm,
a light-weight design and a magnetic circuit formation can be
achieved at the same time.
[0221] In the present experiment example, the spiral magnet
structure has 8 spirals, and the adjacent spirals in an axial
direction of the column-shaped rotation shaft 2 have opposite
magnetic poles, i.e., an N pole and an S pole on outer sides of the
column-shaped rotation shaft in its diametrical direction. That is,
there are provided 4 spiral plate magnet sets which have the N pole
on outer sides in a diametrical direction, and 4 spiral plate
magnet sets which have the S pole on outer sides in a diametrical
direction. Although at least two spirals are necessary to form
opposite magnetic poles, i.e., an N pole and an S pole on outer
sides in a diametrical direction, an 8-sprial structure is employed
in the present invention. Therefore, when the column-shaped
rotation shaft and the spiral plate magnet sets are viewed from a
direction perpendicular to an axis of the column-shaped rotation
shaft, an acute angle (hereinafter, referred to as a spiral angle)
between a direction of a row of magnets forming the spiral and an
axial direction of the column-shaped rotation shaft is set to be
about 41.degree., so that a sharply inclined spiral structure is
obtained.
[0222] FIG. 11 shows the number of spirals of the spiral magnet
sets, and the corresponding spiral angles, and a maximum horizontal
magnetic field and a minimum horizontal magnetic field on closed
plasma loops. A thickness of the spiral magnet is set to be about
12 mm and a substantial width 1101 shown in FIG. 11 is 11 mm. It
can be seen that, if the number of the spirals increases, the
spiral angle is reduced while the maximum horizontal magnetic field
is increased. It can be seen that, if the 8-spiral structure is
employed as in the present embodiment, the spiral angle becomes
41.degree. and, at the same time, the maximum horizontal magnetic
field on the plasma loops exceeds 500 Gauss. In this manner, if the
thickness and the width of the magnet are once selected, the
horizontal magnetic field can be efficiently generated by reducing
the spiral angle by increasing the number of the spirals. Such an
effect is found to be dominant in case the spiral angle is in the
range of about 30.degree. to 70.degree., desirably, 35.degree. to
50.degree..
[0223] From the above, it can be seen that the horizontal magnetic
field of the erosion area 301, i.e., the strength of a magnetic
field parallel to the target surface exceeds 500 Gauss, so that
strength sufficient enough for confining the plasma can be
obtained.
[0224] In order to form a closed loop of high-density plasma, it is
necessary to install a stationary magnet around a rotary magnet.
However, it is also required to reduce a force and a torque
generated at the column-shaped rotation shaft 2 due to the
stationary magnet so as to operate the apparatus stably for a long
period of time.
[0225] For example, as shown in FIG. 8B, though a configuration, in
which a plurality of column-shaped rotation shafts where plate
magnets are arranged in a spiral shape, contributes to a throughput
improvement by enlarging an erosion area and a film forming area on
the target substrate, the adjacent rotation shafts need to have
same-polarity magnets to form a closed high-density plasma loop.
Accordingly, a repulsive force and a torque generated at the
column-shaped rotation shaft increase, which is unsuitable for the
purpose of reducing them.
[0226] In the present experiment example, as shown in FIG. 8A,
spiral structures having opposite polarities are arranged
alternately, so that surrounding stationary magnets are magnetized
in the same vertical direction. Therefore, when viewed from the
surrounding magnets, N poles and S poles of the rotary magnet sets
become alternately close, so that a repulsive force and an
attractive force are offset, whereby the force and the torque are
substantially applied only at both end portions of the rotation
shaft. In the present experiment example, the force and the torque
applied to the column-shaped rotation shaft was measured, and the
force in a vertical direction was about 220 N and the force in a
horizontal direction (rotational direction) was about 60 N.
Further, a rotation torque was about 0.75 (Nm). Compared to a
typical example of a conventional apparatus, both values can be
greatly reduced. Thus, the column-shaped rotation shaft 2 can be
easily rotated by a small motor.
[0227] FIG. 6 illustrates a state where plasma excitation is
performed while rotating the column-shaped rotation shaft 2. FIG. 6
provides photographs showing a change of plasma on the target
surface as time passes. As for conditions of the plasma excitation,
an argon gas was introduced at a rate of about 1000 cc per minute,
and an RF power of about 13.56 MHz was applied at a power level of
about 800 W. Further, the column-shaped rotation shaft 2 was
rotated at about 1 Hz. Plasma could be stably excited until the
column-shaped rotation shaft 2 was rotated up to about 5 Hz. As can
be seen from the left photograph of FIG. 6 (which shows, from top
to bottom, a state of change as time passes), a plasma loop
(erosion loop) 601 is stably generated from a left end of the
rotation shaft and is moved with the rotation of the shaft.
Further, as can be seen from the right photograph of FIG. 6 (which
shows, from top to bottom, a state of change as time passes), the
plasma loop 601 disappears stably to a right end of the rotation
shaft. Further, FIG. 7 illustrates an image of a consumed state of
the target after it has been discharged for a long time. From the
figure, it can be seen that the surface of the target 1 is consumed
not locally but uniformly.
[0228] Meanwhile, if the backing plate 6 becomes thinner, the
target 1 becomes closer to the magnets, so that the horizontal
magnetic field strength on the surface of the target 1 is further
increased. If the horizontal magnetic field strength increases, the
plasma confining effect improves, so that the film forming rate
increases or the plasma excitation efficiency improves. Thus, by
enabling the space 20 to be depressurized and setting the backing
plate 6 to have a thickness smaller than the initial thickness of
the target 1, the film forming rate can be further improved.
[0229] Moreover, since the target 1 is uniformly consumed and the
magnets is moved in a vertical direction according to the
consumption of the target 1, a horizontal magnetic field having
high reproducibility and the same strength can always be formed at
all positions on the target surface, so that film formation
reproducibility improves when the apparatus is continuously
operated for a long period of time.
Second Embodiment
[0230] A second embodiment of the present invention will be
explained in detail with reference to FIG. 12. Descriptions of the
same parts as those of the aforementioned embodiment will be
omitted for the simplicity of description. A magnetron sputtering
apparatus in accordance with the present invention has two spirals.
It can be seen from FIG. 11 that in case of two spirals, a
difference between a maximum horizontal magnetic field and a
minimum horizontal magnetic field becomes small. If a magnetic
field in a loop is uniform, a plasma density in the loop becomes
uniform, so that a uniformity of consumption of a target 1 caused
by rotation of a magnet is more effectively enhanced. This is
because a direction of a peripheral stationary magnet becomes
nearly perpendicular to a direction of a spiral magnet. In this
case, a spiral angle is about 79.degree.. It can be seen that in
order to obtain such a uniformity effectively, a spiral angle is
desirably in a range of about 70.degree. to 88.degree. and, more
desirable, in a range of about 75.degree. to 85.degree.. As can be
seen from FIG. 11, in case of using magnets having substantially
the same thickness and the same width, a value of the maximum
magnetic field decreases as the number of spirals is reduced. In
this case, a plasma density is decreased and a film forming rate is
also decreased, resulting in a deterioration of a throughput of the
apparatus. Accordingly, in the present embodiment, a thickness of
the magnet is increased from about 12 mm to about 20 mm, and
strength of a horizontal magnetic field on a target surface is
increased. As a result, a maximum horizontal magnetic field in a
loop is about 654 Gauss and a minimum horizontal magnetic field is
about 510 Gauss and thus it is possible to accomplish a
distribution of the horizontal magnetic fields more than about 500
Gauss in all loops. In this case, a minimum value of the horizontal
magnetic field reaches about 78% of a maximum value thereof, so
that uniformity which is difficult to achieve in case of using
eight spirals can be ensured.
[0231] In the present embodiment, such a freely rotatable magnet as
denoted by a reference numeral 1201 in FIG. 12 is provided between
a magnetic body cover and a rotary magnet. This magnet 1201 is
configured to be freely rotatable on a shaft 1202. Accordingly,
whenever a spiral magnet is rotated, the magnet 1201 is freely
rotated and generates an attraction force with respect to a
column-shaped rotation shaft. With this configuration, deformation
of the shaft caused by gravity can be prevented, and even if the
shaft is elongated, it is not easily deformed.
[0232] Further, in the present embodiment, a distance between a
substrate to be processed and a target surface is set to about 25
mm. FIG. 13 illustrates a relationship between a distance from the
target surface and a horizontal magnetic field. A negative side on
a horizontal axis corresponds to a magnet side and a positive side
corresponds to a substrate side. In a sputtering film forming
method of the present embodiment, film forming uniformity is good
and a strong magnetic field of about 500 Gauss or more is generated
on the target surface, so that plasma is excited only in a vicinity
of the target surface. As can be seen from FIG. 13, when the
distance between the target surface and the substrate is about 25
mm, strength of the magnetic field at that position is about 100
Gauss or less which is about 1/5 or less of the strength of the
magnetic field on the target surface, so that plasma excitation is
hardly affected. Accordingly, it can be seen that even if the
target is brought close to the substrate at a distance of about 30
mm or less or desirably, about 20 mm or less, a uniform film can be
formed because the magnet is rotated. Further, by researching a
configuration of the magnet, the magnetic field on a surface of the
substrate can be set to about 20 Gauss or less. In this way, the
substrate to be processed is brought close to the target surface,
so that a film forming particle sputtered from the target is
scarcely adhered to a wall of a processing chamber or a shield
member and is adhered to the substrate to be processed.
Accordingly, a film formation can be performed with high target use
efficiency.
Third Embodiment
[0233] A third embodiment of the present invention will be
explained in detail with reference to the drawings. Further,
descriptions of the same parts as those of the aforementioned
embodiments will be omitted for the simplicity of description. A
magnetron sputtering apparatus in accordance with the present
invention is especially suitable to be used as a reciprocating film
forming apparatus as illustrated in FIG. 9.
[0234] In FIG. 9, a reference numeral 401 denotes a processing
chamber; a reference numeral 402 denotes a gate valve; a reference
numeral 403 denotes a substrate to be processed; and a reference
numeral 404 is a rotary magnet plasma exciting unit of the third
embodiment. The length of the spiral in a direction of the axis is
set to about 307 mm in the first embodiment, whereas it is set to
about 270 mm in this embodiment. A frequency of plasma excitation
power is set to about 13.56 MHz. However, the frequency is
desirably as high as about 100 MHz in order to achieve a high
plasma density and a low temperature electron. A length of the
plasma exciting unit is about 2.7 m, while a wavelength at a
frequency of about 100 MHz is about 3 m. In this way, if the length
of the exciting unit is nearly the same as the wavelength, a
standing wave may be excited, resulting in non-uniform plasma. If
the frequency is about 13.56 MHz, the wavelength thereof is about
22.1 m. Therefore, the length of the plasma exciting unit is
sufficiently shorter than the wavelength and thus the plasma does
not become non-uniform due to the standing wave.
[0235] In the present embodiment, four rotary magnet plasma
exciting units 404 are used. Therefore, it is possible to
substantially increase a film forming rate. The number of the
exciting units is not limited to four. The substrate 403 is a glass
substrate having a size of about 2.2 m.times.2.5 m. In the present
embodiment, the lengthwise side of the substrate is about 2.5 m and
the substrate is reciprocated in a direction perpendicular to a
column-shaped rotation shaft serving as a rotary magnet plasma
exciting unit, so that a substantially uniform film can be formed
on the substrate. In order to form a uniform film, the substrate
403 may be moved in one direction instead of being reciprocated, or
the rotary magnet plasma exciting unit 404 may be moved. In the
present embodiment, by reciprocating the substrate 403, a part of
the substrate is consecutively exposed to a plasma region in which
the plasma is excited by the rotary magnet plasma exciting unit, so
that a uniform thin film can be formed. A rotation speed of the
rotary magnet is set to be shorter than a transit time of the
substrate, so that it is possible to form a uniform film without
instantaneous influence of an erosion pattern. Typically, a transit
speed of the substrate is about 60 sec/sheet and a rotation speed
of the rotary magnet is about 10 Hz. Moreover, in the present
embodiment, the substrate to be processed is reciprocated, but the
film forming apparatus may be configured to form a film by passing
the substrate through one or more rotary magnet plasma exciting
units only once.
Fourth Embodiment
[0236] A fourth embodiment of the present invention will be
explained in detail with reference to FIG. 15. Descriptions of the
same parts as those of the aforementioned embodiments will be
omitted for the simplicity of description. In a magnetron
sputtering apparatus in accordance with the present invention, a
power feed point that supplies a plasma excitation power into a
backing plate 6 and a target 1 is divided into plural ones.
[0237] Above all, there will be explained a problem of a
conventional apparatus having only one power feed point.
[0238] In a magnetron sputtering apparatus, as a substrate to be
processed is scaled up, a length of a rotation shaft of a rotary
magnet is increased. For example, in order to process a large-sized
glass substrate having a size of about 2.88 m.times.3.08 m, a
sputtering apparatus having a rotation shaft of about 3.2 m in
length is necessitated. The target also has a length equivalent to
the rotation shaft. When the target has such a length, a length of
the target is equivalent to the wavelength of a high frequency
power. Thus, for example, if plasma is excited by feeding a power
from only one central point, a standing wave is generated and thus
the plasma becomes non-uniform. Furthermore, since high current
flows in an axis direction due to high current flowing from the
plasma, an unintended voltage is generated due to an inductance
effect, resulting in deterioration of uniformity.
[0239] Hereinafter, there will be explained a magnetron sputtering
apparatus having a power feed point which is divided into plural
ones.
[0240] FIG. 15 illustrates a schematic view of a magnetron
sputtering apparatus in accordance with the present invention. A
reference numeral 2 denotes a rotary magnet set (column-shaped
rotation shaft); a reference numeral 1 denotes a target; a
reference numeral 6 denotes a backing plate; a reference numeral
15a denotes a metal plate surrounding the rotary magnet set 2 and
electrically connected with the backing plate; a reference numeral
12a is a power supply for generating a high frequency power by
which plasma is excited; and a reference numeral 12b is a power
feed point for applying the high frequency power to the target. In
the drawings, FIG. 15A is a cross sectional view perpendicular to
the rotation shaft and FIG. 15B is a diagram viewed from a lateral
side of the rotation shaft (viewed from a direction of an arrow X
of FIG. 15A). Since the apparatus processes a substrate of about 3
m.times.3 m size, a length of the target in the axis direction is
about 3.2 m which is longer than the length of the substrate.
[0241] A frequency of the high frequency power is about 13.56 MHz.
Representative frequencies of powers, half-wavelengths in a vacuum
and 1/10 (one tenth) values thereof are provided in Table 1
below.
TABLE-US-00001 TABLE 1 Half-wavelength(m) Half-wavelength/10(m)
Frequency(MHz) in vacuum in vacuum 13.56 11.1 1.11 27 5.6 0.56 40
3.8 0.38 100 1.5 0.15
[0242] At a frequency of 13.56 MHz, the half-wavelength in a vacuum
is 11.1 m. The plasma is excited via a sheath, i.e., a space charge
layer having a thickness of several mm between a target surface and
the plasma. That is, the sheath exists between the plasma and the
target.
[0243] Since the plasma serves as a good conductor, parallel plate
lines are formed by the plasma and the target in the axis
direction. If an electromagnetic wave is propagated to the parallel
plate lines, its wavelength becomes equal to a wavelength in a
vacuum. A wavelength is in inverse proportion to a frequency, and
at a frequency of 13.56 MHz, the half-wavelength is 11.1 m which
can not be neglected in consideration of the target length of about
3.2 m.
[0244] A high frequency is more advantageous to obtain high density
plasma with low electron temperature which are efficient for
improvement in a film forming rate or for decrease in damage.
Therefore, it is efficient to use a power with a frequency of about
100 MHz.
[0245] In this case, the vacuum half-wavelength is about 1.5 m
which is shorter than the target length of about 3.2 m. When the
wavelength is substantially equivalent to the target length in this
way, if a power is fed at a certain point, a standing wave is
generated and thus non-uniform plasma is excited.
[0246] Further, a parasitic inductance necessarily exists in the
target. When a parasitic inductance per unit length is expressed as
L, impedance of 2.pi.f.times.L is generated. If a high current I of
several to several tens of ampere flows from the plasma in the axis
direction of the target, a voltage of 2.pi.f.times.L.times.I is
generated, so that there occurs a problem that a power does not
reach a distant position from the power feed point.
[0247] Since the impedance is proportional to the frequency, the
aforementioned effect becomes conspicuous as the frequency
increases.
[0248] In order to suppress such an effect, by dividing the power
feed point into plural ones to set a pitch of the power feed point
to be about 1/10 or less of the vacuum half-wavelength, the distant
position from the power feed point does not exist and the current
flowing into one power feed point is reduced. That is, the present
inventor found that uniformity could be obtained by reducing the
current flowing in the axis direction of the target.
[0249] In the present embodiment, since a high frequency power of
about 13.56 MHz is used and 1/10 of the vacuum half-wavelength is
1.11 m, four power feed points are provided at a distance of about
0.8 m shorter than the vacuum half-wavelength. In this way, it is
possible to form a film on a large-sized substrate of about 3
m.times.3 m size without deterioration of plasma uniformity and
uniformity of film formation. In the present embodiment, only a
high frequency power of about 13.56 MHz is used to excite the
plasma, but the frequency is not limited thereto. Therefore, it may
be possible to superpose a DC power or a power having a different
frequency thereon.
Fifth Embodiment
[0250] A fifth embodiment of the present invention will be
explained in detail with reference to FIG. 16. Descriptions of the
same parts as those of the aforementioned embodiments will be
omitted for the simplicity of description. In a magnetron
sputtering apparatus in accordance with the present invention, a
magnet 19a for generating a magnetic field is provided within a
mounting table 19 for mounting a substrate 10 to be processed,
i.e., at a side opposite to a target 1 across the substrate.
[0251] In FIG. 16 illustrating the embodiment of the present
invention, a reference numeral 2 denotes a rotary magnet set
(column-shaped rotation shaft); a reference numeral 10 denotes a
substrate to be processed; a reference numeral 19 denotes a
mounting table for mounting the substrate 10 and provided at a side
opposite to a target 1 across the substrate 10; and a reference
numeral 19a is an in-stage magnet installed within the mounting
table 19, for generating a magnetic field. If there is no magnet
installed within the mounting table 19, magnetic force lines
generated from an N-pole magnet which is a spiral magnet positioned
in a plasma loop illustrated in FIG. 3 and generated by a
spiral-shaped rotary magnet reach the substrate 10, so that plasma
is simultaneously transported along the magnetic force lines and
plasma damage occurs during a film formation. If the in-stage
magnet 19a forms an N-pole toward the target 1, it is possible to
control the magnetic force lines not to reach the substrate 10 and
to detour in a horizontal direction. Accordingly, a film formation
can be performed without the plasma reaching the substrate 10, and
in particular, the film formation can be performed without damage
to the substrate 10 in its early stage. Further, in the present
embodiment, in order for the magnetic force lines generated from
the N-pole magnet, i.e., the spiral magnet positioned in the plasma
loop not to reach the substrate 10, the in-stage magnet also forms
an N-pole toward the target. However, depending on a design of the
spiral magnet, magnetic force lines generated from a magnet
positioned between loops may reach the substrate 10. Therefore,
polarity of the in-stage magnet 19a needs to be appropriately
changed. Furthermore, the in-stage magnet 19a is installed within
the mounting table 19 in the present embodiment but its position is
not limited thereto, so that a stationary magnet may be installed
under the target 1 or under the mounting table 19 or the magnetic
field may be generated by a current.
Sixth Embodiment
[0252] A sixth embodiment of the present invention will be
explained in detail with reference to FIGS. 17 to 37. Descriptions
of the same parts as those of the aforementioned embodiments will
be omitted for the simplicity of description. A magnetron
sputtering apparatus in accordance with the present invention
includes a rotary magnet in accordance with the first embodiment
having a magnet configuration in which a target use efficiency that
is determined by a target consumption distribution determined based
on Larmor radius of electron confined in the horizontal magnetic
field and a radius of curvature of the magnetic field is set to be
about 80% or more.
[0253] A configuration of the magnetron sputtering apparatus is the
same as illustrated in FIG. 1. Therefore, description thereof will
be omitted.
[0254] As shown in FIG. 7, local consumption of a target in the
magnetron sputtering apparatus in accordance with the first
embodiment is remarkably improved as compared to a conventional
sputtering apparatus.
[0255] It can be seen that an erosion, that is, consumption
distribution is uniform in a rotation axis direction of the target,
i.e., in a proceeding direction of a plasma loop, whereas the
consumption distribution of the target is not uniform in a
direction perpendicular to the rotation axis direction (proceeding
direction of the plasma loop). In other words, as shown in FIG. 18
with actual measurement values, both end portions of the target
(end portions of the plasma loop) are greatly consumed as compared
to a central portion of the target.
[0256] In order to find a relationship between a consumption
distribution of the target surface and a configuration of the
apparatus, the present inventors considered the followings.
[0257] The present inventors took notice of Larmor radius of
electrons confined in the magnetic field.
[0258] As illustrated in FIG. 17, the Larmor radius r.sub.c of
electrons confined in the magnetic field is a radius of a circle
when a charged particle in the magnetic field makes a circular
motion by a Lorentz force. If a circular horizontal magnetic loop
having a perfect axial symmetry is formed, there is a relationship
between an erosion half-width and the Larmor radius as follows.
[0259] W: Erosion half-width
[0260] R: Radius of curvature of horizontal magnetic field
[0261] r.sub.c: Larmor radius
[0262] Here, if the radius of curvature of horizontal magnetic
field is sufficiently larger than the Larmor radius, the erosion
half-amplitude can be derived from the following Formula b.
[Eq. 3]
W.apprxeq.2 {square root over (2Rr.sub.c)} . . . Formula b (Formula
2)
[0263] The Larmor radius can be expressed as follows.
[ Eq . 4 ] r c = m e v .perp. eB Formula c ##EQU00002##
[0264] m.sub.e: Electron mass
[0265] V.sub..perp.: Electron velocity component perpendicular to
the magnetic field
[0266] e: Elementary electric charge
[0267] B: Magnetic flux density
[0268] Further, a secondary electron generated from the target is
accelerated by a sheath electric field in a direction perpendicular
to the horizontal magnetic field. However, since a velocity
component of a vertical magnetic field is small in an erosion area,
the sheath electric field is approximately orthogonal to the
magnet.
[0269] Accordingly, a formula is obtained as follows.
[Eq. 5]
v.sub..perp..apprxeq. {square root over (2e|V.sub.DC|/m.sub.e)}
Formula d
[0270] V.sub.DC: Self-bias voltage (DC voltage generated on the
target 1 with respect to the ground)
[0271] By substituting Formula d into Formula c, a formula is
obtained as follows.
[ Eq . 6 ] r c = 34 V D C ( V ) B ( Gauss ) ( mm ) Formula e (
Formula 1 ) ##EQU00003##
[0272] When the self-bias voltage V.sub.DC and the magnetic flux
density B are varied, Larmor radiuses can be obtained as shown in
Table 2. The erosion half-widths W at that time are shown in Table
3. Table 3 provides a case where the radius R of curvature of a
magnetic field is 20 mm and another case where the radius R of
curvature of a magnetic field is 10 mm.
TABLE-US-00002 TABLE 2 |V.sub.DC|, Larmor radius (mm) in case of
varying a magnetic field B(G) |V.sub.DC| (V) 300 400 500 600 200
1.6 1.2 1.0 0.8 300 2.0 1.5 1.2 1.0 400 2.3 1.7 1.4 1.1 500 2.5 1.9
1.5 1.3 600 2.8 2.1 1.7 1.4
TABLE-US-00003 TABLE 3 B(G) |V.sub.DC| (V) 300 400 500 600 Erosion
half-width (mm) in case where a radius of curvature of a magnetic
field is 20 mm 200 16.0 13.9 12.4 11.3 300 17.7 15.3 13.7 12.5 400
19.0 16.5 14.8 13.5 500 20.1 17.4 15.6 14.2 600 21.1 18.3 16.3 14.9
Erosion half-width (mm) in case where a radius of curvature of a
magnetic field is 10 mm 200 11.3 9.8 8.8 8.0 300 12.5 10.9 9.7 8.9
400 13.5 11.7 10.4 9.5 500 14.2 12.3 11.0 10.1 600 14.9 12.9 11.5
10.5
[0273] However, in the magnetron sputtering apparatus in accordance
with the present invention, the horizontal magnetic field loop is
not a circle having a perfect axial symmetry, like a plasma loop as
illustrated in FIG. 6. Therefore, the horizontal magnetic field
(i.e., Larmor radius) and the radius of curvature of a magnetic
field are varied depending on a position within the loop.
[0274] Accordingly, the erosion half-width is also varied depending
on a position within the loop.
[0275] In the magnetron sputtering apparatus in accordance with the
present invention, it is not obvious that a plasma density is
uniform at any position within the horizontal magnetic field loop.
However, assuming that the plasma density is uniform at any
position within the loop, the present inventors allowed a phase to
be varied by rotating the magnet; calculated an erosion half-width
for each case and an average phase; and obtained an erosion
distribution of the target. Further, as a result of comparing the
obtained erosion distribution with an actual erosion distribution
(experimental values), it is proved that they almost correspond to
each other, as illustrated in FIG. 18. That is, in the magnetron
sputtering apparatus in accordance with the present invention, it
can be seen that the erosion distribution can be calculated by
using a formula that is obtained by using a horizontal magnetic
field loop formed into a circle having a perfect axial symmetry as
described above.
[0276] In other words, it can be seen that the target erosion
distribution can be calculated from the radius R of curvature of a
magnetic field and the Larmor radius r.sub.c of an electron
(defined by the self-bias voltage V.sub.DC and the magnetic flux
density B).
[0277] Therefore, by selecting a configuration of each part of the
magnetron sputtering apparatus in accordance with the present
invention, it is possible to calculate a consumption distribution
of the target and thus to uniformize the target consumption
distribution, i.e., to improve a target use efficiency.
Accordingly, a target use efficiency of about 80% or more, which
can not be accomplished by a conventional technique, can be
accomplished by the present invention.
[0278] In other words, it is possible to obtain a magnetron
sputtering apparatus having a magnet configuration in which a
target use efficiency that is determined by a target consumption
distribution determined based on Larmor radius defined by the
generated self-bias voltage and a radius of curvature of the
magnetic field is set to be about 80% or more.
[0279] Hereinafter, a method of optimizing, i.e., uniformizing a
target consumption distribution based on the above calculation will
be explained with reference to the drawings.
[0280] The present inventors took notice of a parameter, in
particular, a shape of the spiral-shaped plate magnet set 3 of the
magnetron sputtering apparatus, and attempted to optimize the
target consumption distribution based on the above calculation.
[0281] Above all, a use efficiency as an indicator of optimization
was defined.
[0282] As described above, when the magnetron sputtering apparatus
is operated, the target 1 is activated and sputtered by the plasma,
thus being consumed to a state illustrated in FIG. 21B from a state
illustrated in FIG. 21A.
[0283] In this case, when a thickness 1b of a rest of the most
deeply consumed portion is about 5% of an initial thickness 1a of
the non-consumed target, the target is to be replaced in
consideration of a target's life. Assuming that the rotation axis
of the rotary magnet set is sufficiently long, the use efficiency
can be expressed by the following formula.
Use efficiency=Cross sectional area of consumed portion (plane
perpendicular to an axial direction)/Initial cross sectional area
Formula f
[0284] The present inventors allowed a shape of the spiral-shaped
plate magnet set 3 to be changed and calculated a target
consumption distribution and a use efficiency based on Formula f as
explained below.
[0285] First, a shape parameter of the spiral-shaped plate magnet
set 3 used when calculating the target consumption distribution and
the use efficiency will be explained with reference to FIGS. 19 and
20.
[0286] As illustrated in FIG. 19, the spiral-shaped plate magnet
set 3 is wound around the column-shaped rotation shaft 2 and the
adjacent spiral-shaped plate magnet sets 3 are spaced apart from
each other at a distance s.
[0287] An extended direction of the spiral-shaped plate magnet set
3 is inclined with respect to the rotation axis of the
column-shaped rotation shaft 2. Here, an acute angle therebetween
is defined as a.
[0288] Further, if the number of the spiral-shaped plate magnet set
3 (the number m of loops) is increased without changing widths Wn
and Ws of the magnets, an angle .alpha. of the spiral-shaped plate
magnet set 3 with respect to the rotation axis is decreased as
illustrated in FIG. 27. If a diameter Da of the rotary magnet, the
widths Wn and Ws of the magnet, the distance s between the magnets
and the number m of the loops are set, the angle .alpha. is
automatically determined.
[0289] Furthermore, as illustrated in FIG. 19, the adjacent
spiral-shaped plate magnet sets 3 have an N-pole and an S-pole
respectively at the outside of the column-shaped rotation shaft 2
in a diametrical direction, and the spiral-shaped plate magnet set
3 has predetermined widths Wn and Ws.
[0290] In FIG. 19, the width of the spiral-shaped plate magnet set
3 having the N-pole at the outside of the column-shaped rotation
shaft 2 in a diametrical direction is denoted as Wn, while the
width o the spiral-shaped plate magnet set 3 having the S-pole at
the outside of the column-shaped rotation shaft 2 in a diametrical
direction is denoted as Ws.
[0291] Further, as illustrated in FIG. 20, the spiral-shaped plate
magnet set 3 has a thickness tm in a diametrical direction of the
column-shaped rotation shaft 2.
[0292] Hereinafter, a result of optimizing the consumption
distribution based on the above-described parameter will be
explained.
[0293] The present inventors took notice of the distance s between
the magnets of the spiral-shaped plate magnet set 3 illustrated in
FIG. 19.
[0294] A target consumption distribution and a use efficiency are
calculated while varying the distance s between the magnets of the
spiral-shaped plate magnet set 3 from about 8 mm to about 17
mm.
[0295] Further, the present inventors set the number of loops of
the spiral-shaped plate magnet set 3 to 1; the diameter Da of the
magnet to about 150 mm; the widths Wn and Ws of the magnets to
about 14 mm; and the thickness tm of the magnet to about 12 mm.
FIG. 22 illustrates a case where a distance s between magnets is
set to be about 8 mm, about 12 mm and about 17, respectively. A
relationship between the distance s between magnets and a
consumption distribution is shown in FIG. 23, and a relationship
between use efficiency, a horizontal magnetic field and a distance
between magnets is shown in FIG. 24.
[0296] It can be seen from FIG. 24 that when the magnet distance s
is about 11 mm or more, the stable use efficiency exceeding about
80% is obtained and when the magnet distance s is about 12 mm, a
highest use efficiency is obtained.
[0297] Further, it is found that strength of the horizontal magnet
field becomes strong as the distance s between magnets is
increased.
[0298] Thereafter, the present inventors took notice of a plate
thickness tm of the spiral-shaped plate magnet set 3 illustrated in
FIG. 20.
[0299] A target consumption distribution and a use efficiency are
calculated while varying the plate thickness tm of the
spiral-shaped plate magnet set 3 from about 5 mm to about 15
mm.
[0300] Further, a diameter of the column-shaped rotation magnet is
set to be about 150 mm, a width of the magnet to about 14 mm and a
distance between magnets to about 12 mm.
[0301] In this case, a relationship between a plate thickness tm
and a consumption distribution is shown in FIG. 25, and a
relationship between a use efficiency, strength of a magnetic field
and a plate thickness is shown in FIG. 26.
[0302] As illustrated in FIG. 26, it can seen that if the plate
thickness tm is in a range from about 5 mm to about 15 mm, the use
efficiency exceeds about 80%, and if the plate thickness tm is in a
range from about 9 mm to about 12 mm, the use efficiency exceeds
about 85%, so that a highest use efficiency is obtained in this
range.
[0303] Subsequently, the present inventors took notice of the
number m of loops of the spiral-shaped plate magnet set 3
illustrated in FIG. 19.
[0304] A target consumption distribution and a use efficiency are
calculated while varying the number m of loops of the spiral-shaped
plate magnet set 3 from about 1 to about 5.
[0305] Further, a diameter of the column-shaped rotation magnet is
set be to about 150 mm, a width of the magnet to about 14 mm and a
distance between magnets to about 12 mm.
[0306] In this case, a relationship between the number m of loops
and an angle .alpha. is shown in FIG. 27, and a relationship
between the number m of loops and a consumption distribution is
shown in FIG. 28. A relationship between a use efficiency, strength
of a magnetic field and the number m of loops is shown in FIG.
29.
[0307] As illustrated in FIG. 29, the use efficiency exceeds about
80% regardless of the number m of loops, but as the number m of
loops is increased, the use efficiency tends to decrease.
[0308] Further, it can be seen that the highest use efficiency can
be obtained when the number m of loops is 2, and a single loop or
double loops are desirable. A relationship between a use
efficiency, strength of a magnetic field and an angle .alpha. is
shown in FIG. 30 and the efficiency exceeds about 80% in an angle
range from about 57.degree. to about 84.degree., desirably, from
about 75.degree. to about 85.degree.. An inclined angle is
desirably close to about 90.degree. because the plasma loops move
more uniformly with respect to the target at this angle. An
inclined angle in a conventional magnetron sputtering apparatus is
about 49.degree., which may cause the conventional magnetron
sputtering apparatus to have a target use efficiency of about
50%.
[0309] Then, the present inventors took notice of the width Wn of
the magnet with the N-pole facing a surface and the width Ws of the
magnet with the S-pole facing the surface in the spiral-shaped
plate magnet set 3 illustrated in FIG. 19.
[0310] To be specific, the width Ws of the magnet with the S-pole
facing the surface is set to about 14 mm and the width Wn of the
magnet with the N-pole facing the surface is set to about 14 mm and
about 18 mm, and then a target consumption distribution and a use
efficiency are calculated. In this case, a diameter of the magnet
is set to about 150 mm and a distance between magnets is set to
about 12 mm.
[0311] FIG. 31 illustrates a diagram viewed from a target in a case
where a width Ws of an S-pole magnet is set to about 18 mm which is
wider than a width of an N-pole magnet and a loop shape is not much
changed and only a horizontal magnetic field is increased. FIG. 32
shows a relationship between a width of the S-pole magnet and an
consumption distribution, and FIG. 33 shows a relationship between
a use efficiency and strength of a horizontal magnetic field.
[0312] As shown in FIGS. 32 and 33, when the width Ws is about 18
mm, it is possible to obtain the horizontal magnetic field strength
of about 500 Gauss or more, a consumption width of about 12 cm and
the use efficiency of about 87.6%. Therefore, it can be seen that
the width of the S-pole magnet is desirably wider than that of the
N-pole magnet.
[0313] Thereafter, a scale-up of the magnet was considered. FIG. 34
illustrates erosion distribution when a magnet diameter is set to
about 94 mm (here, a width of a plasma loop was about 76 mm and a
width of a magnetic field exceeding about 500 G was about 42 mm),
150 mm and 260 mm (here, a width of a plasma loop was about 118 mm
and a width of a magnetic field exceeding about 500 G was about 50
mm). FIG. 35 illustrates a relationship between a width of a plasma
loop and a width of erosion. In this case, one loop was used. As
illustrated in FIG. 35, it can be seen that even though the magnet
diameter is increased, the width of erosion is not much increased,
and it is desirable to use more than one magnet having a diameter
of about 150 mm. In particular, in order to perform a high speed
film formation on a large-sized substrate, it is desirable to
arrange more than one rotary magnet plasma excitation unit in a
moving direction of the substrate such that a rotation axis is
orthogonal to the moving direction of the substrate.
[0314] Further, there is no limitation on a parameter for obtaining
a use efficiency of about 80%, and various kinds of parameters can
be selected. However, it can be seen that variation of the
self-bias voltage in a range from about 100 V to about 700 V does
not much affect the target use efficiency. Therefore, each
parameter of a magnet configuration is important.
[0315] As described above, in accordance with the sixth embodiment,
it can be seen that the consumption distribution of the target is
simulated with the radius of curvature of the magnetic field and
the Larmor radius of the electron and in this simulation, the
target use efficiency of about 80% or more is obtained by adjusting
parameters such as the distance s between the magnets of the
spiral-shaped plate magnet set 3, the number m of the loops of the
spiral-shaped plate magnet set 3, the magnet plate thickness tm, a
difference between the width Wn of magnet with the N-pole facing
the surface and the width Ws of the magnet with the S-pole facing
the surface and the diameter of the rotary magnet.
[0316] Hereinafter, a method for improving a material use
efficiency by consuming a material of the target without waste will
be discussed. Referring to FIG. 36, some material particles
sputtered from the target 1 are adhered on the plasma shield member
16. Assuming that a deposit efficiency is calculated by dividing
the total amount of the material particles sputtered from the
target 1 by the total amount of the material particles deposited on
the substrate 10, the material use efficiency can be obtained by
multiplying the target use efficiency by the deposit efficiency.
Accordingly, in order to improve the material use efficiency, it is
necessary to increase the target use efficiency and also to
increase the deposit efficiency, as described above. In order to do
so, as illustrated in FIG. 37, it is desirable to adjust a width of
a slit 18 to be approximated to the width of the plasma to make a
difference therebetween less than about 20 mm, desirably, about 10
mm. Further, the slit 18 and the plasma shield member 16 are
positioned as closely as possible to the target (a distance
therebetween is desirably in a range of about 15 mm to 3 mm).
[0317] A relationship between each parameter and a material use
efficiency is shown in Table 4. In order to improve the material
use efficiency, it is necessary to improve the target use
efficiency, increase the width of the plasma, approximate the width
of the slit to the width of the plasma and position the slit as
closely as possible to the target, as described above.
TABLE-US-00004 TABLE 4 Width of high density plasma: 120 mm,
Distance between target and slit: 15 mm Total material use Target
use Deposit efficiency on Silt efficiency (%) efficiency (%)
substrate (%) width (mm) 24 50 48 60 32 50 63 80 44 50 88 120 53 60
88 120 82 85 96 120 91 95 96 120
[0318] The size of the magnet and the size of the substrate are not
limited to the above-described embodiments. Further, in the above
embodiments, though the surface magnetic pole of the peripheral
stationary magnet is set to be an S-pole, it may be set to be an
N-pole. In this case, the width of the spiral-shaped plate magnet
with an N-pole is needed to be wider than that of the spiral-shaped
plate magnet with an S-pole.
[0319] Further, in the sixth embodiment, each plate magnet of the
spiral-shaped plate magnet sets 3 is magnetized in a direction
perpendicular to its plate surface, and the plate magnets are fixed
to the column-shaped rotation shaft 2 in a spiral shape to form
plural spirals. The spirals adjacent to each other in the axis
direction of the column-shaped rotation shaft 2 have different
magnetic poles, i.e., an N-pole and an S-pole on outer sides of the
column-shaped rotation shaft 2 in its diametrical direction, in the
same manner as the first embodiment.
[0320] Furthermore, in the sixth embodiment, a stationary outer
peripheral plate magnet 4 is configured to surround the rotary
magnet set serving as a spiral-shaped plate magnet set 3 when
viewed from the target 1 and the stationary outer peripheral plate
magnet 4 is magnetized such that its side facing the target 1 has
an S-pole.
[0321] However, if the stationary outer peripheral plate magnet 4
is made of a ferromagnetic body, it does not have to be magnetized
in advance.
[0322] Further, as for the plate magnets of the spiral-shaped plate
magnet set 3, if one (first spiral) of the adjacent spirals is
magnetized in advance, the other (second spiral) may be made of a
non-magnetized ferromagnetic body.
[0323] Even in this configuration, since the magnetized spiral
magnetizes another ferromagnetic body, a loop-shaped plane magnetic
field surrounding the N-pole (or S-pole) on its surface in a loop
shape can be formed. Therefore, loop-shaped plasma in the same
shape as a conventional one can be obtained.
Seventh Embodiment
[0324] A seventh embodiment of the present invention will be
explained in detail with reference to FIGS. 38 and 39. Further,
descriptions of the same parts as those of the aforementioned
embodiments will be omitted for the simplicity of description. A
magnetron sputtering apparatus in accordance with the present
invention is provided with a free rotary magnet (moving magnet) 21
between an end portion of a spiral-shaped stationary magnet set 3
illustrated in the first embodiment and a short side of a
stationary outer peripheral plate magnet 4 orthogonal to the
rotation axis direction.
[0325] As illustrated in FIGS. 38 and 39, the free rotary magnet
(moving magnet) 21 is installed between the end portion of the
spiral-shaped stationary magnet set 3 and the short side of the
stationary outer peripheral plate magnet 4 orthogonal to the
rotation axis direction.
[0326] The moving magnet 21 is formed in a column shape and
includes a rotation shaft 21a parallel to the short side of the
stationary outer peripheral plate magnet 4. The moving magnet 21
can be freely rotated on the rotation shaft 21a in a direction of
B1 as indicated in FIG. 39.
[0327] Further, the moving magnet 21 is magnetized in a direction
perpendicular to the rotation shaft 21a.
[0328] The moving magnet 21 is desirably made of a magnet having a
high residual magnetic flux density, a high coercive force and high
energy product in order to weaken a strong magnetic field. In the
present embodiment, SS400 containing Fe as a major component is
used for the moving magnet 21.
[0329] Furthermore, a surface of the moving magnet is desirably
covered with a non-magnetic substance having a corrosion resistance
to the plasma.
[0330] If the surface of the moving magnet 21 is covered with the
non-magnetic substance (not illustrated), it is possible to prevent
the surface of the moving magnet 21 from being corroded by the
plasma and also prevent particles of the magnetic substance from
being adhered on the surface f the moving magnet 21. Accordingly,
the inside of the apparatus is prevented from being
contaminated.
[0331] The non-magnetic substance is desirably made of a material
such as stainless or aluminum alloy having a corrosion resistance
to the plasma.
[0332] Further, in the magnetron sputtering apparatus in accordance
with the present invention, in order to prevent a temperature rise
of the target, a coolant is circulated through a passage 8 to cool
the target. Additionally or alternatively, cooling units may be
installed in both spaces which are in the vicinity of upper sides
of both ends of the backing plate 6 and below the spiral-shaped
plate magnet sets 3.
[0333] Moreover, for example, by setting pressures in both spaces
(depressurized) above and below the backing plate provided with the
target to be substantially same, the backing plate can be thinner
and, desirably, the backing plate can have a thickness equal to or
less than about 30% of the initial thickness of the target.
[0334] Hereinafter, an erosion formation and an operation of the
moving magnet 21 during the erosion formation in accordance with
the seventh embodiment will be explained in detail. In the same
manner as the first embodiment, in case that the spiral-shaped
plate magnet sets 3 are formed by arranging a plurality of plate
magnets on a column-shaped rotation shaft 2, an N-pole of the plate
magnet is approximately surrounded by two S-poles adjacent to the
N-pole and a S-pole of outer peripheral stationary magnet when the
spiral-shaped plate magnet sets 3 are viewed from the target side,
as illustrated in FIG. 3. In this configuration, magnetic force
lines start from the N-pole of the spiral-shaped plate magnet sets
3 and end at the surrounding S-poles. As a result, a multitude of
closed plasma loops 301 are formed on the target surface spaced
apart from a plate magnet surface at a certain distance. Further,
as the column-shaped rotation shaft 2 is rotated, the multitude of
plasma loops 301 are moved in a rotation axis direction. In FIG. 3,
the plasma loops 301 move in a direction indicated by an arrow.
Besides, the plasma loops 301 are generated in sequence from one
end of the spiral-shaped plate magnet set 3 and disappear in
sequence at the other end thereof.
[0335] In the seventh embodiment like the first embodiment, if an
argon gas is introduced and plasma excitation is performed while
rotating the column-shaped rotation shaft 2, a plasma loop 601 is
stably generated from a left end of the rotation shaft and is moved
with the rotation of the shaft, as illustrated in FIG. 6. Then, the
plasma loop 601 disappears stably to a right end of the rotation
shaft, as can be seen from a right photograph of FIG. 6 (which
shows, from top to bottom, a state of change as time passes).
[0336] In this condition, a target 1 is activated and sputtered by
the gas excited into plasma and a mounting table 19 is moved such
that a substrate 10 to be processed faces the target 1. Thus, the
sputtered target 1 is deposited on a surface of the substrate 10,
thereby forming a thin film thereon.
[0337] In this case, since a direction of a polarity of the
spiral-shaped plate magnet set 3 changes as time passes, a polarity
of a short side of the stationary outer peripheral plate magnet 4
becomes the same as a polarity of a facing surface of the
spiral-shaped magnet depending on a rotation coordinate, thereby
forming a strong magnetic field.
[0338] For example, as illustrated in FIG. 39, when an end surface
of the spiral-shaped plate magnet set 3 with an S-pole facing
toward the surface is positioned to face the short side of the
stationary outer peripheral plate magnet 4, a part of facing
surfaces 23 may have the same polarity of the S-poles. Accordingly,
a strong magnetic field is formed due to repulsion between the same
polarities.
[0339] At a region where the strong magnetic field is formed, a
consumption rate of the target 1 is relatively increased, so that
an erosion distribution becomes non-uniform.
[0340] If the erosion distribution is not uniform, target use
efficiency is deteriorated and a thickness of the formed thin film
also becomes non-uniform.
[0341] In the seventh embodiment, the moving magnet 21 which is
freely rotatable is installed between the facing surfaces 23 of the
spiral-shaped plate magnet set 3 and the stationary outer
peripheral plate magnet 4, so that the magnet 21 freely rotates to
face the facing surfaces 23 each having an opposite polarity to
that of the moving magnet 21, thereby weakening the strong magnetic
field as illustrated in FIG. 39. Alternatively, by using a
non-freely rotatable and non-illustrated actuator or the like, the
moving magnet 21 may be synchronized with rotation of the spiral
magnet and rotated in a direction of B1 as indicated in FIG. 39 so
as to face the facing surfaces 23 each having an opposite polarity
to that of the moving magnet 21.
[0342] In accordance with the seventh embodiment, the magnetron
sputtering apparatus includes the moving magnet 21 installed
between the facing surfaces 23 of the spiral-shaped plate magnet
set 3 and the stationary outer peripheral plate magnet 4, and the
generated strong magnetic field is reduced by rotating the moving
magnet 21 to face the facing surfaces 23 each having an opposite
polarity to that of the moving magnet 21.
[0343] As a result, the strong magnetic field generated from the
end portion of the spiral magnet can be reduced from about 700 G or
more to about 600 G. Accordingly, a local consumption of the target
1 can be prevented and an erosion distribution becomes uniform,
thereby improving a target use efficiency.
[0344] Further, in the seventh embodiment, each plate magnet of the
spiral-shaped plate magnet set 3 is magnetized in a direction
perpendicular to its surface, and the plate magnets are fixed to
the column-shaped rotation shaft 2 in a spiral shape to form plural
spirals. The spirals adjacent to each other in the axis direction
of the column-shaped rotation shaft 2 have different magnetic
poles, i.e., an N-pole and an S-pole on outer sides of the
column-shaped rotation shaft in its diametrical direction, in the
same manner as the first embodiment.
[0345] Furthermore, in the seventh embodiment, a stationary outer
peripheral plate magnet 4 is configured to surround the rotary
magnet set serving as a spiral-shaped plate magnet set 3 when
viewed from the target 1 and the stationary outer peripheral plate
magnet 4 is magnetized such that its side facing the target 1 has
an S-pole.
[0346] However, if the stationary outer peripheral plate magnet 4
is made of a ferromagnetic body, it does not have to be magnetized
in advance.
[0347] Further, as for the plate magnets of the spiral-shaped plate
magnet set 3, if one (first spiral) of the adjacent spirals is
magnetized in advance, the other (second spiral) may be made of a
non-magnetized ferromagnetic body.
[0348] Even in this configuration, since the magnetized spiral
magnetizes another ferromagnetic body, a loop-shaped plane magnetic
field surrounding the N-pole (or S-pole) on its surface in a loop
shape can be formed. Therefore, loop-shaped plasma in the same
shape as a conventional one can be obtained.
Eighth Embodiment
[0349] An eighth embodiment of the present invention will be
explained in detail with reference to FIGS. 40 to 42. Further,
descriptions of the same parts as those of the aforementioned
embodiments will be omitted for the simplicity of description.
[0350] As illustrated in FIGS. 40 to 42, in a magnetron sputtering
apparatus in accordance with the present invention, moving magnets
33 are installed at both end portions of the spiral-shaped magnet
between a lateral surface of a column-shaped rotation shaft 2 and a
long side of a stationary outer peripheral plate magnet 4.
[0351] The moving magnets 33 are formed in a column shape and
include a rotation shaft 33a parallel to the rotation axis of the
column-shaped rotation shaft 2. The moving magnets 33 can be
rotated on the rotation shaft 33a in a direction of B2 as indicated
in FIG. 42 by using non-illustrated actuators.
[0352] Further, the moving magnets 33 are magnetized in a direction
perpendicular to its rotation direction.
[0353] Hereinafter, operations of the moving magnets 33 will be
explained.
[0354] As described above, the magnetron sputtering apparatus in
accordance with the present invention performs a film formation
while rotating the spiral-shaped plate magnet set 3, so that a
direction of a polarity of the spiral-shaped plate magnet set 3
changes as time passes.
[0355] Therefore, a polarity of a long side of the stationary outer
peripheral plate magnet 4 becomes the same as a polarity of a
facing surface of the spiral-shaped magnet depending on a rotation
coordinate, whereby a strong magnetic field may be formed.
[0356] For example, as illustrated in FIG. 42, when a lateral
surface of the spiral-shaped plate magnet set 3 with an S-pole
facing toward the surface is positioned to face the long side of
the stationary outer peripheral plate magnet 4, a part of facing
surfaces 23a may have the same polarity of the S-poles.
Accordingly, a strong magnetic field is formed due to repulsion
between the same polarities.
[0357] At a region where the strong magnetic field is formed, a
consumption rate of the target 1 is relatively increased, so that
an erosion distribution becomes non-uniform.
[0358] If the erosion distribution is not uniform, target use
efficiency is deteriorated.
[0359] In the eighth embodiment, the moving magnet 33 is installed
between the facing surfaces 23a of the spiral-shaped plate magnet
set 3 and the stationary outer peripheral plate magnet 4. By using
a non-illustrated actuator or the like, the moving magnet 33 may be
rotated in a direction of B2 as indicated in FIG. 42 so as to face
the facing surfaces 23a each having an opposite polarity to that of
the moving magnet 33, thereby weakening the generated strong
magnetic field as illustrated in FIG. 42. The moving magnet 33 may
be freely rotated.
[0360] That is, the magnetic field is controlled by using the
moving magnet 33, so that an erosion distribution can be uniform
and consumption of the target 1 and a thickness of the formed thin
film can be uniform, thereby improving a target use efficiency.
[0361] In accordance with the eighth embodiment, the magnetron
sputtering apparatus includes the moving magnet 33 installed
between the lateral surface of the column-shaped rotation shaft 2
and the long side of the stationary outer peripheral plate magnet
4, and the generated strong magnetic field is reduced by rotating
the moving magnet 33 to face the facing surfaces 23a each having an
opposite polarity to that of the moving magnet 33.
[0362] Accordingly, the eighth embodiment has the same effect as
the seventh embodiment.
[0363] Further, in the eighth embodiment, each plate magnet of the
spiral-shaped plate magnet set 3 is magnetized in a direction
perpendicular to its surface, and the plate magnets are fixed to
the column-shaped rotation shaft 2 in a spiral shape to form plural
spirals. The adjacent spirals in the axis direction of the
column-shaped rotation shaft 2 have opposite magnetic poles, i.e.,
an N-pole and an S-pole on outer sides of the column-shaped
rotation shaft 2 in its diametrical direction, in the same manner
as the first embodiment.
[0364] Furthermore, in the eighth embodiment, a stationary outer
peripheral plate magnet 4 is configured to surround the rotary
magnet set serving as spiral-shaped plate magnet set 3 when viewed
from the target 1 and the stationary outer peripheral plate magnet
4 is magnetized such that its side facing the target 1 has an
S-pole.
[0365] However, if the stationary outer peripheral plate magnet 4
is made of a ferromagnetic body, it does not have to be magnetized
in advance.
[0366] Further, as for the plate magnets of the spiral-shaped plate
magnet set 3, if one (first spiral) of the adjacent spirals is
magnetized in advance, the other (second spiral) may be made of a
non-magnetized ferromagnetic body.
[0367] Even in this configuration, since the magnetized spiral
magnetizes another ferromagnetic body, a loop-shaped plane magnetic
field surrounding the N-pole (or S-pole) can be formed on its
surface in a loop shape. Therefore, loop-shaped plasma in the same
shape as a conventional one can be obtained.
Ninth Embodiment
[0368] A ninth embodiment of the present invention will be
explained in detail with reference to FIGS. 43 and 44. Further,
descriptions of the same parts as those of the aforementioned
embodiments will be omitted for the simplicity of description.
[0369] As illustrated in FIGS. 43 and 44, in a magnetron sputtering
apparatus, moving magnets 43 are respectively installed between the
lateral surface of a column-shaped rotation shaft 2 and the long
side of the stationary outer peripheral plate magnet 2 and can be
moved in an axis direction of the column-shape rotation shaft
2.
[0370] The moving magnet 43 is formed in a column shape and can be
moved in a direction of B3 as indicated in FIG. 44, i.e., in the
axis direction of column-shape rotation shaft 2 by using a
non-illustrated actuator.
[0371] Further, the moving magnets 43 are magnetized in a direction
perpendicular to its moving direction.
[0372] Hereinafter, an operation of the moving magnet 43 will be
explained.
[0373] As described above, since a direction of a polarity of a
spiral-shaped plate magnet set 3 changes as time passes, a polarity
of the stationary outer peripheral plate magnet 4 becomes the same
as a polarity of a facing surface of the spiral-shaped plate magnet
set 3 depending on a rotation coordinate, whereby a strong magnetic
field may be formed.
[0374] For example, as illustrated in FIG. 44, when a part of a
lateral surface of the spiral-shaped plate magnet set 3 with an
S-pole facing the surface is positioned to face the long side of
the stationary outer peripheral plate magnet 4, a part of facing
surfaces may have the same polarity of the S-poles. Accordingly, a
strong magnetic field is formed due to repulsion between the same
polarities.
[0375] At a region where the strong magnetic field is formed, a
consumption rate of the target 1 is relatively increased, so that
an erosion distribution becomes non-uniform.
[0376] If the erosion distribution is not uniform, a consumption of
the target 1 is not uniform and target use efficiency is
deteriorated.
[0377] In the ninth embodiment, the moving magnets 43 are installed
between the facing surfaces of the spiral-shaped plate magnet set 3
and the stationary outer peripheral plate magnet 4. By using a
non-illustrated actuator or the like, the moving magnet 43 may be
moved in a direction of B3 as indicated in FIG. 44 so as to face
the facing surfaces each having an opposite polarity to that of the
moving magnet 43, thereby reducing the generated strong magnetic
field.
[0378] That is, the magnetic field is controlled by using the
moving magnet 43, so that an erosion distribution can be uniform
and consumption of the target 1 and a thickness of the formed thin
film can be uniform, thereby improving a target use efficiency.
[0379] Further, the moving magnet 43 may be configured to be
rotated in the axis direction of the column-shaped rotation shaft
2.
[0380] With this configuration, the ninth embodiment has the same
effect as the eighth embodiment.
[0381] In accordance with the ninth embodiment, the magnetron
sputtering apparatus includes the moving magnet 43 installed
between the lateral surface of the column-shaped rotation shaft 2
and the stationary outer peripheral plate magnet 4, and the
generated strong magnetic field is weakened by moving the moving
magnet 43 to face the facing surfaces each having an opposite
polarity to that of the moving magnet 43.
[0382] Accordingly, the ninth embodiment has the same effect as the
eighth embodiment.
[0383] Further, in the ninth embodiment, each plate magnet of the
spiral-shaped plate magnet set 3 is magnetized in a direction
perpendicular to its surface, and the plate magnets are fixed to
the column-shaped rotation shaft 2 in a spiral shape to form plural
spirals. The spirals adjacent to each other in the axis direction
of the column-shaped rotation shaft 2 have different magnetic
poles, i.e., an N-pole and an S-pole on outer sides of the
column-shaped rotation shaft 2 in its diametrical direction, in the
same manner as the first embodiment.
[0384] Furthermore, in the ninth embodiment, a stationary outer
peripheral plate magnet 4 is configured to surround the rotary
magnet set serving as spiral-shaped plate magnet set 3 when viewed
from the target 1 and the stationary outer peripheral plate magnet
4 is magnetized such that its side facing the target 1 has an
S-pole.
[0385] However, if the stationary outer peripheral plate magnet 4
is made of a ferromagnetic body, it does not have to be magnetized
in advance.
[0386] Further, as for the plate magnets of the spiral-shaped plate
magnet set 3, if one of the adjacent spirals is magnetized in
advance (i.e., it is a magnet), the other may be made of a
non-magnetized ferromagnetic body.
[0387] Even in this configuration, since the magnetized spiral
magnetizes another ferromagnetic body, a loop-shaped plane magnetic
field surrounding the N-pole (or S-pole) can be formed on its
surface in a loop shape. Therefore, loop-shaped plasma in the same
shape as a conventional one can be obtained.
Tenth Embodiment
[0388] A tenth embodiment of the present invention will be
explained in detail with reference to FIG. 45. Further,
descriptions of the same parts as those of the aforementioned
embodiments will be omitted for the simplicity of description.
[0389] As illustrated in FIG. 45, a collimator 51 is installed in a
slit 18 in a plasma shield member 16 and the slit 18 is positioned
to face the target 1.
[0390] The collimator 51 is fixed to the plasma shield member
16.
[0391] The collimator 51 is made of, e.g., Ti, Ta, Al, stainless
steel or metal containing these materials.
[0392] Further, the collimator 51 is connected with a
non-illustrated power supply circuit that applies a voltage to the
collimator 51 and serves as a removal unit. A target alignment
mechanism is made up of the collimator 51 and the power supply
circuit.
[0393] When the magnetron sputtering apparatus is operated,
sputtered target materials reach the collimator 51 and target
materials having different directions and angles from those of the
collimator 51 are reflected by the collimator 51 or adhered to the
collimator 51.
[0394] Accordingly, angles of the target materials reaching a
substrate 10 to be processed (which is moved to right side in the
drawing to be positioned right below the slit 18) can be adjusted
to be identical with each other.
[0395] The target materials adhered to the collimator 51 can be
removed by the non-illustrated power supply circuit as the removal
unit for applying a voltage to the collimator 51.
[0396] Further, in the tenth embodiment, each plate magnet of the
spiral-shaped plate magnet set 3 is magnetized in a direction
perpendicular to its surface, and the plate magnets are fixed to
the column-shaped rotation shaft 2 in a spiral shape to form plural
spirals. The adjacent spirals in the axis direction of the
column-shaped rotation shaft have opposite magnetic poles, i.e., an
N-pole and an S-pole on outer sides of the column-shaped rotation
shaft 2 in its diametrical direction, in the same manner as the
first embodiment.
[0397] Furthermore, in the tenth embodiment, a stationary outer
peripheral plate magnet 4 is configured to surround the rotary
magnet set serving as spiral-shaped plate magnet set 3 when viewed
from the target 1 and the stationary outer peripheral plate magnet
4 is magnetized such that its side facing the target 1 has an
S-pole.
[0398] However, if the stationary outer peripheral plate magnet 4
is made of a ferromagnetic body, it does not have to be magnetized
in advance.
[0399] Further, as for the plate magnets of the spiral-shaped plate
magnet set 3, if one (first spiral) of the adjacent spirals is
magnetized in advance, the other (second spiral) may be made of a
non-magnetized ferromagnetic body.
[0400] Even in this configuration, since the magnetized spiral
magnetizes another ferromagnetic body, a loop-shaped plane magnetic
field surrounding the N-pole (or S-pole) can be formed on its
surface in a loop shape. Therefore, loop-shaped plasma in the same
shape as a conventional one can be obtained.
Eleventh Embodiment
[0401] An eleventh embodiment of the present invention will be
explained in detail with reference to FIG. 46. Further,
descriptions of the same parts as those of the aforementioned
embodiments will be omitted for the simplicity of description. In
the present embodiment, a collimator 61 is installed to cover a
substrate 10 to be processed instead of being installed in a slit
18 and the collimator 61 and the substrate 10 are transferred
together.
[0402] The collimator 61 covers an upper surface of the substrate
10 but is not fixed to a main body of the sputtering apparatus.
[0403] With this configuration, the collimator 61 moves together
with the substrate 10.
[0404] In this way, since the collimator 10 is configured to cover
the substrate 10 and move with the substrate 10 as described above,
an amount of target material to be adhered to the collimator 61 is
reduced as compared to the tenth embodiment.
[0405] Further, in the eleventh embodiment, each plate magnet of
the spiral-shaped plate magnet set 3 is magnetized in a direction
perpendicular to its surface, the plate magnets are fixed to the
column-shaped rotation shaft 2 in a spiral shape to form plural
spirals. The spirals adjacent to each other in the axis direction
of the column-shaped rotation shaft 2 have different magnetic
poles, i.e., an N-pole and an S-pole on outer sides of the
column-shaped rotation shaft 2 in its diametrical direction, in the
same manner as the first embodiment.
[0406] Furthermore, in the eleventh embodiment, a stationary outer
peripheral plate magnet 4 is configured to surround the rotary
magnet set serving as spiral-shaped plate magnet set 3 when viewed
from the target 1 and the stationary outer peripheral plate magnet
4 is magnetized such that its side facing the target 1 has an
S-pole.
[0407] However, if the stationary outer peripheral plate magnet 4
is made of a ferromagnetic body, it does not have to be magnetized
in advance.
[0408] Further, as for the plate magnets of the spiral-shaped plate
magnet set 3, if one (first spiral) of the adjacent spirals is
magnetized in advance, the other may be made of a non-magnetized
ferromagnetic body.
[0409] Even in this configuration, since the magnetized spiral
magnetizes another ferromagnetic body, a loop-shaped plane magnetic
field surrounding the N-pole (or S-pole) can be formed on its
surface in a loop shape. Therefore, loop-shaped plasma in the same
shape as a conventional one can be obtained.
[0410] Though the present invention has been explained with respect
to the above-described embodiments, a size of the magnet, a size of
the substrate, and the like are not limited to the mentioned
examples.
INDUSTRIAL APPLICABILITY
[0411] A magnetron sputtering apparatus in accordance with the
present invention can be used not only for forming a thin film such
as an insulating film, a conductive film on a semiconductor wafer
or the like, but also for forming various kinds of films on a
substrate such as a glass substrate in a flat display device and
for performing sputtering film formation in fabricating a memory
device, a magnetic recording device and other electronic
devices.
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