U.S. patent application number 11/984057 was filed with the patent office on 2008-05-15 for polishing method for semiconductor wafer and polishing apparatus for semiconductor wafer.
Invention is credited to Dai Fukushima, Takeo Kubota, Atsushi Shigeta.
Application Number | 20080113590 11/984057 |
Document ID | / |
Family ID | 39369740 |
Filed Date | 2008-05-15 |
United States Patent
Application |
20080113590 |
Kind Code |
A1 |
Kubota; Takeo ; et
al. |
May 15, 2008 |
Polishing method for semiconductor wafer and polishing apparatus
for semiconductor wafer
Abstract
A polishing method for a semiconductor wafer having a polishing
target surface at a periphery portion thereof is disclosed. The
method includes pressing a polishing member against the polishing
target surface along a circumference of the semiconductor wafer by
a plurality of pressing portions while rotating the semiconductor
wafer in a circumferential direction, thereby polishing the
polishing target surface of the semiconductor wafer.
Inventors: |
Kubota; Takeo; (Tsukuba-shi,
JP) ; Shigeta; Atsushi; (Fujisawa-shi, JP) ;
Fukushima; Dai; (Kamakura-shi, JP) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Family ID: |
39369740 |
Appl. No.: |
11/984057 |
Filed: |
November 13, 2007 |
Current U.S.
Class: |
451/37 ;
156/345.23; 451/287; 451/288 |
Current CPC
Class: |
B24B 9/065 20130101 |
Class at
Publication: |
451/037 ;
451/287; 451/288; 156/345.23 |
International
Class: |
B24B 7/04 20060101
B24B007/04; B24B 41/06 20060101 B24B041/06 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 14, 2006 |
JP |
2006-308250 |
Claims
1. A polishing method for a semiconductor wafer having a polishing
target surface at a periphery portion thereof, the method
comprising: pressing a polishing member against the polishing
target surface along a circumference of the semiconductor wafer by
a plurality of pressing portions while rotating the semiconductor
wafer in a circumferential direction, thereby polishing the
polishing target surface of the semiconductor wafer.
2. The method according to claim 1, wherein the plurality of
pressing portions include a plurality of individually controllable
displacement portions.
3. The method according to claim 2, wherein each of the
displacement portions has a pressing head which is movable in a
direction substantially vertical to a contact region of the
polishing member and the polishing target surface.
4. The method according to claim 3, wherein an elastic member is
interposed between the pressing heads and the polishing member.
5. The method according to claim 2, wherein each of the
displacement portions has a hollow portion whose internal pressure
is controllable.
6. The method according to claim 2, wherein a displacement amount
of each of the displacement portions is controlled in accordance
with a curvature of the polishing target surface.
7. The method according to claim 1, wherein the plurality of
pressing portions include a plurality of convex portions.
8. The method according to claim 7, wherein the convex portions
have elasticity.
9. The method according to claim 8, wherein the plurality of convex
portions are fixed to a base portion that is positioned between the
convex portions and the polishing member and has elasticity.
10. The method according to claim 7, wherein at least one of a
height, a size, and hardness of each of the convex portions is
adjusted in accordance with an arrangement position of each of the
convex portions.
11. The method according to claim 7, wherein a distal end of each
of the convex portions has a rounded shape.
12. The method according to claim 1, wherein a distribution of a
pressure applied to the polishing target surface has a plurality of
peaks based on the plurality of pressing portions.
13. The method according to claim 12, wherein heights of the
plurality of peaks are substantially equal to each other.
14. The method according to claim 1, wherein the polishing target
surface is polished while moving a polishing region of the
polishing member in the circumferential direction of the
semiconductor wafer.
15. The method according to claim 1, wherein the polishing member
is selected from a polishing tape and an abrasive pad.
16. A polishing apparatus for a semiconductor wafer having a
polishing target surface at a periphery portion thereof,
comprising: a rotation unit which rotates the semiconductor wafer
in a circumferential direction; and a pressing unit which presses a
polishing member against the polishing target surface of the
semiconductor wafer which is rotated by the rotation unit to polish
the polishing target surface, the pressing unit having a plurality
of pressing portions which press the polishing member against the
polishing target surface along a circumference of the semiconductor
wafer.
17. The apparatus according to claim 16, wherein the plurality of
pressing portions include a plurality of individually controllable
displacement portions.
18. The apparatus according to claim 17, wherein each of the
displacement portions has a pressing head which is movable in a
direction substantially vertical to a contact region of the
polishing member and the polishing target surface.
19. The apparatus according to claim 17, wherein each of the
displacement portions has a hollow portion whose internal pressure
is controllable.
20. The apparatus according to claim 16, wherein the plurality of
pressing portions include a plurality of convex portions.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from prior Japanese Patent Application No. 2006-308250,
filed Nov. 14, 2006, the entire contents of which are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a polishing method for a
semiconductor wafer and a polishing apparatus for a semiconductor
wafer.
[0004] 2. Description of the Related Art
[0005] With miniaturization of a semiconductor device, polishing a
rim portion (periphery portion) of a semiconductor wafer is
becoming important (see, e.g., JP-A 2005-7518 (KOKAI)). Usually, a
polishing member, e.g., a polishing tape is pressed against a
polishing target surface at a periphery portion of a wafer to
perform polishing while rotating the wafer in a circumferential
direction.
[0006] However, since the periphery portion of the wafer has a
curvature in the circumferential direction, pressing the polishing
member against the polishing target surface with a uniform pressure
is difficult. That is, the pressure is relatively increased at a
central part of a polishing region, but the pressure is relatively
decreased at both ends of the polishing region. Therefore, a large
pressure difference occurs between the central part and both the
ends of the polishing region.
[0007] In a conventional technology, when pressing the polishing
member against the polishing target surface at the periphery
portion of the semiconductor wafer in this manner, pressing the
region that is wide in the circumferential direction with the
uniform pressure is difficult. Therefore, effectively applying the
pressure to the wide region at the periphery portion of the
semiconductor wafer to carry out polishing is difficult.
BRIEF SUMMARY OF THE INVENTION
[0008] According to a first aspect of the present invention, there
is provided a polishing method for a semiconductor wafer having a
polishing target surface at a periphery portion thereof, the method
comprising: pressing a polishing member against the polishing
target surface along a circumference of the semiconductor wafer by
a plurality of pressing portions while rotating the semiconductor
wafer in a circumferential direction, thereby polishing the
polishing target surface of the semiconductor wafer.
[0009] According to a second aspect of the present invention, there
is provided a polishing apparatus for a semiconductor wafer having
a polishing target surface at a periphery portion thereof,
comprising: a rotation unit which rotates the semiconductor wafer
in a circumferential direction; and a pressing unit which presses a
polishing member against the polishing target surface of the
semiconductor wafer which is rotated by the rotation unit to polish
the polishing target surface, the pressing unit having a plurality
of pressing portions which press the polishing member against the
polishing target surface along a circumference of the semiconductor
wafer.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0010] FIG. 1 is a view schematically showing an outline structure
of a polishing apparatus for a semiconductor wafer according to a
first embodiment of the present invention;
[0011] FIG. 2 is a view schematically showing an outline structure
of the polishing apparatus for the semiconductor wafer according to
the first embodiment of the present invention;
[0012] FIG. 3 is a view showing a distribution of a pressure
applied to a polishing target surface according to the first
embodiment of the present invention;
[0013] FIGS. 4A and 4B are views schematically showing a positional
relationship between the polishing target surface and a polishing
tape according to the first embodiment of the present
invention;
[0014] FIG. 5 is a view schematically showing an outline structure
of a polishing apparatus for a semiconductor wafer according to a
second embodiment of the present invention;
[0015] FIG. 6 is a view schematically showing an outline structure
of a polishing apparatus for a semiconductor wafer according to a
third embodiment of the present invention;
[0016] FIG. 7 is a view for explaining a polishing method for a
semiconductor wafer according to a fourth embodiment of the present
invention;
[0017] FIG. 8 is a view showing a polishing region according to the
fourth embodiment of the present invention; and
[0018] FIG. 9 is a view showing a polishing region according to the
fourth embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Embodiments according to the present invention will now be
explained hereinafter with reference to the accompanying
drawings.
Embodiment 1
[0020] FIGS. 1 and 2 are views schematically showing an outline
structure of a polishing apparatus for a semiconductor wafer
according to a first embodiment of the present invention. FIG. 1 is
a view seen from a direction parallel to a main surface of a
semiconductor wafer, and FIG. 2 is a view seen from a direction
vertical to the main surface of the semiconductor wafer.
[0021] This polishing apparatus includes a rotation unit 20 which
rotates a semiconductor wafer 10 in a circumferential direction,
and a pressing unit 30 which presses a polishing tape (a polishing
member) 41 against a polishing target surface to polish the
polishing target surface at a rim portion (periphery portion) 11 of
the semiconductor wafer 10 that is rotated by the rotation unit 20.
Further, this polishing apparatus includes a tape movement unit 50
that moves the polishing tape 41, and the tape movement unit 50 is
formed of a tape supplying reel 51 and a tape collecting reel
52.
[0022] The rotation unit 20 has a holding portion 21 that holds the
semiconductor wafer 10 in a vacuum chuck system, and a rotation
shaft 22 that is used to rotate the holding portion 21. When the
semiconductor wafer 10 held by the holding portion 21 is rotated
around the rotation shaft 22, the polishing target surface at the
periphery portion 11 of the semiconductor wafer 10 can be polished
by the polishing tape 41.
[0023] The pressing unit 30 has an elastic member 31 formed of a
silicone rubber, a plurality of pressing heads (displacement
portions) 32 serving as a plurality of pressing portions, a
plurality of shafts 33 which displace the pressing heads 32, a
plurality of cylinders 34 which hold the shafts 33, and a
controller 35 which controls displacements of the pressing heads
32. The pressing heads 32 can move in a vertical direction to a
contact region of the polishing tape 41 and the polishing target
surface of the semiconductor wafer 10. When the pressing heads 32
are displaced, the elastic member 31 and the polishing tape 41 are
deformed. As a result, the polishing tape 41 can be pressed against
the polishing target surface at the periphery portion 11 of the
semiconductor wafer 10 along a circumference of the semiconductor
wafer 10. Displacements of the respective pressing heads 32 can be
independently controlled by the controller 35.
[0024] FIG. 3 is a view showing a distribution of a pressure
applied to the polishing target surface in the circumferential
direction when the polishing tape 41 is pressed against the
polishing target surface of the semiconductor wafer 10 by the
pressing unit 30. In this embodiment, the pressing unit 30 has the
three pressing heads 32, and hence the pressure distribution has
three peaks based on displacements of the pressing heads 32. That
is, pressing forces of the plurality of pressing portions (the
pressing heads 32) enable providing the plurality of peaks in the
pressure distribution. Since the peaks in the pressure distribution
can be dispersed in this manner according to this embodiment, the
polishing tape 41 can be pressed against the polishing target
surface at the periphery portion 11 of the semiconductor wafer with
the pressure that is substantially uniformed in a wide region.
Therefore, the pressure can be effectively applied to the wide
region in the polishing target surface to perform polishing. As a
result, a polishing efficiency can be improved to shorten a
polishing time.
[0025] Furthermore, according to this embodiment, displacements of
the respective pressing heads 32 can be independently controlled.
Therefore, accurately controlling displacement amounts of the
respective pressing heads 32 enables optimizing the pressure
distribution. For example, heights of the plurality of peaks
(intensities of the pressure) in the pressure distribution can be
uniformed. Therefore, the above-explained effect can be further
enhanced.
[0026] FIGS. 4A and 4B are views schematically showing a positional
relationship between the polishing target surface of the
semiconductor wafer 10 and the polishing tape 41. FIG. 4A is a view
showing a position of the polishing tape 41 when polishing an end
facet (the polishing target surface) at the periphery portion 11 of
the semiconductor wafer 10, and FIG. 4B is a view showing a
position of the polishing tape 41 when polishing a slant surface
(the polishing target surface) 13 at the periphery portion 11 of
the semiconductor wafer 10.
[0027] A curvature radius of the end facet 12 is smaller than that
of the slant surface 13. Therefore, when a conventional polishing
apparatus is used to perform polishing, a polishing region width of
the end facet 12 becomes narrower than that of the slant surface
13. Accordingly, when polishing the end facet 12, a region that is
not used for polishing is relatively increased in a width direction
of the polishing tape 41. As a result, an amount of using the
polishing tape 41 is necessarily increased, which results in a rise
of a polishing cost.
[0028] In this embodiment, the pressing unit 30 has the plurality
of pressing heads 32 as explained above. Therefore, the polishing
tape 41 can be pressed against the end facet 12 over the wide
region when polishing the end facet 12. Accordingly, a width of the
region used for polishing can be increased, and an amount of using
the polishing tape 41 can be reduced.
[0029] An operation of this embodiment will now be explained.
[0030] First, as shown in FIG. 1, the semiconductor wafer 10 is set
on the holding portion 21 of the rotation unit 20. Moreover, the
semiconductor wafer 10 is rotated in the circumferential direction,
and the polishing tape 41 is pressed against the polishing target
surface at the periphery portion 11 of the semiconductor wafer 10
by using the plurality of pressing heads 32 to polish the polishing
target surface. Additionally, polishing is carried out while
supplying the polishing tape 41 from the tape supplying reel 51 to
the tape collecting reel 52. Based on this polishing, a film (e.g.,
a silicon oxide film or a silicon nitride film) that has adhered to
the end facet 12 or the slant surface 13 of the semiconductor wafer
10 can be removed.
[0031] A rotating speed of the semiconductor wafer 10 is, e.g., 500
rpm. Further, as the polishing tape 41, one obtained by, e.g.,
securing diamond abrasives on a polyethylene terephthalate (PET)
base material (e.g., a width: 70 mm, a thickness: 50 .mu.m) by a
binder is used. A feed speed of the polishing tape 41 is, e.g., 50
mm/min.
[0032] Although a polishing order of the end facet and the slant
surface is not restricted in particular, polishing is carried out
in the order of, e.g., the upper slant surface, the end facet, and
the lower slant surface. When polishing each surface, a
displacement amount of each pressing head 32 is accurately
controlled in accordance with a curvature of each surface so that
an optimum pressure can be applied in the width direction of the
polishing tape 41. As a result, both the end facet and the slant
surface can be polished with the pressure optimized in the wide
region.
[0033] As explained above, according to this embodiment, since the
pressing unit has the plurality of pressing portions, the plurality
of peaks can be provided in the pressure distribution in the
circumferential direction of the semiconductor wafer. Since the
peaks in the pressure distribution can be dispersed in this manner,
the pressure substantially uniformed in the wide region can be
applied. Therefore, since the pressure can be effectively applied
to the wide region at the periphery portion of the semiconductor
wafer to perform polishing, the polishing efficiency can be
improved, and the polishing time can be reduced. Furthermore, a
width of the polishing tape use region can be increased, and an
amount of using the polishing tape can be decreased. Moreover, in
this embodiment, displacements of the plurality of pressing
portions are independently controlled. Therefore, the pressure
distributions can be individually optimized with respect to the
respective surfaces (the polishing target surfaces) with different
curvatures at the periphery portion of the semiconductor wafer.
Additionally, each polishing target surface can be polished in the
thus optimized pressure distribution.
[0034] It is to be noted that the polishing tape is used as the
polishing member in this embodiment, such a fixed abrasive pad as
explained in the following third embodiment may be used as the
polishing member.
Embodiment 2
[0035] A second embodiment according to the present invention will
now be explained. Since a basic structure of a polishing apparatus
and a basic polishing method are the same as those in the first
embodiment, thereby omitting an explanation of the particulars
described in the first embodiment.
[0036] FIG. 5 is a view schematically showing an outline structure
of a polishing apparatus according to this embodiment.
[0037] In this embodiment, a structure of a pressing unit 30 is
different from that in the first embodiment. In the pressing unit
30 according to this embodiment, an elastic member 31 is formed of
a base portion 31a and a plurality of convex portions 31b, and the
plurality of convex portions 31b function as a plurality of
pressing portions. Specifically, the convex portions 31b are fixed
to the base portion 31a positioned between the convex portions 31b
and a polishing tape (a polishing member) 41. Further, although the
plurality of pressing heads 32, the plurality of shafts 33, and the
plurality of cylinders 34 are provided in the first embodiment, the
number of a pressing head 32, the number of a shaft 33, and the
number of a cylinder 34 are all one in this embodiment.
[0038] As explained above, the plurality of convex portions 31b are
interposed between the pressing head 32 and the polishing tape 41
in this embodiment. Therefore, when the pressing head 32 is
displaced, the convex portions 31b are pressed, and pressing forces
from the convex portions 31b enable pressing the polishing tape 41
against a polishing target surface at a periphery portion 11 of a
semiconductor wafer 10.
[0039] When the polishing tape 41 is pressed against the periphery
portion of the semiconductor wafer 10, a displacement amount of the
central convex portion 31b becomes larger than those of the convex
portions 31b provided on both sides. Therefore, increasing heights
of the convex portions 31b provided on both sides to be larger than
a height of the central convex portion 31b is desirable to enable
accurately pressing all the three convex portions 31b by using the
pressing head 32. Alternatively, sizes of the convex portions 31b
on both sides may be increased to be larger than a size of the
central convex portion 31b. Alternatively, hardness of the convex
portions 31b on both sides may be increased beyond that of the
central convex portion 31b. That is, it is preferable that at least
one of the height, the size, and the hardness of each convex
portion 31b is adjusted in accordance with an arrangement position
of each convex portion 31b. Furthermore, as explained in the first
embodiment, a curvature radius of an end facet of the semiconductor
wafer 10 is different from that of a slant surface of the same.
Therefore, it is desirable for a distal end of each convex portion
31b to have a rounded shape in order to enable accurately pressing
all the three convex portions 31b by using the pressing head 32
irrespective of the curvature radius.
[0040] As explained above, in this embodiment, the pressing unit 30
has three convex portions 31b. Therefore, a pressure distribution
has three peaks corresponding to the three convex portions 31b.
That is, pressure forces of the plurality of pressing portions (the
convex portions 31b) enable providing the plurality of peaks in the
pressure distribution in a circumferential direction of the
semiconductor wafer. Therefore, like the first embodiment, the
peaks in the pressure distribution can be dispersed in this
embodiment. Consequently, the polishing tape 41 can be pressed
against the periphery portion 11 of the semiconductor wafer 10 with
a pressure substantially uniformed over a wide region. Therefore,
the pressure can be effectively applied to the wide region to
polish both the end facet and the slant surface of the
semiconductor wafer 10. Moreover, adjusting the heights, the sizes,
or the hardness of the plurality of convex portions 31b enables
optimizing the pressure distribution. As a result, like the first
embodiment, a polishing efficiency can be improved, and a polishing
time can be shortened. Additionally, like the first embodiment, a
width of a polishing tape use region can be increased, thereby
decreasing an amount of using the polishing tape.
[0041] It is to be noted that the polishing tape is used as the
polishing member in this embodiment, such a fixed abrasive pad as
explained in the following third embodiment may be used as the
polishing member.
Embodiment 3
[0042] A third embodiment according to the present invention will
now be explained. It is to be noted that a basic structure of a
polishing apparatus and a basic polishing method are similar to
those in the first embodiment, thereby omitting an explanation of
the particulars described in the first embodiment.
[0043] FIG. 6 is a view schematically showing an outline structure
of a polishing apparatus according to this embodiment.
[0044] In this embodiment, a structure of a pressing unit 30 is
different from that in the first embodiment. The pressing unit 30
according to this embodiment has a plurality of hollow portions
(displacement portions) 36 which are formed of membranes and
function as a plurality of pressing portions, a plurality of tubes
37 connected with the hollow portions 36, a gas supply portion 38
which supplies a gas, e.g., air into the hollow portions 36 via the
tubes 37, and a controller 35 which controls displacements of the
hollow portions 36. Internal pressures of the respective hollow
portions 36 can be independently controlled by the controller
35.
[0045] Further, in this embodiment, a fixed abrasive pad 42 is used
as a polishing member. The fixed abrasive pad 42 does not move like
the polishing tape but is fixed at a predetermined position. This
fixed abrasive pad 42 is obtained by, e.g., burying ceria abrasives
in a resin having elasticity.
[0046] In this embodiment, when an amount of supplying the gas into
the hollow portions 36 is controlled, displacements of the
respective hollow portions 36 can be controlled. As a result, the
fixed abrasive pad 42 is deformed to enable pressing the fixed
abrasive pad 42 against a periphery portion of a semiconductor
wafer 10.
[0047] Furthermore, in this embodiment, the internal pressures of
the respective hollow portions 36 can be independently controlled.
Therefore, accurately controlling the internal pressures of the
respective hollow portions 36 enables precisely controlling
displacements of the respective hollow portions 36, thereby
optimizing a pressure distribution. It is to be noted that a
relatively large force must be applied to a peripheral part rather
than a central part of the fixed abrasive pad 42 in order to deform
the fixed abrasive pad 42 along the periphery portion of the
semiconductor wafer 10. Therefore, it is desirable to increase the
internal pressures of the hollow portions 36 from the hollow
portion 36 at the central part toward the hollow portions 36 at the
peripheral part.
[0048] As explained above, in this embodiment, since the pressing
unit 30 has the plurality of hollow portions 36, a plurality of
peaks can be provided in a pressure distribution in a
circumferential direction of the semiconductor wafer 10 by pressing
forces from the plurality of pressing portions (the hollow portions
36). Therefore, like the first embodiment, peaks in the pressure
distribution can be dispersed in this embodiment. Therefore, the
fixed abrasive pad 42 can be pressed against a polishing target
surface at the periphery portion 11 of the semiconductor wafer 10
with a pressure substantially uniformed in a wide region. Further,
in this embodiment, the internal pressures of the respective hollow
portions 36 are independently controlled. Therefore, the pressure
distributions can be individually optimized with respect to
respective surfaces (polishing target surfaces) with different
curvatures at the periphery portion 11 of the semiconductor wafer
10. Furthermore, the polishing target surfaces can be polished in
the thus optimized pressure distributions. Therefore, like the
first embodiment, the pressure can be effectively applied to the
wide region to polish both an end facet and a slant surface of the
semiconductor wafer 10. As a result, like the first embodiment, a
polishing efficiency can be improved, and a polishing time can be
reduced.
[0049] It is to be noted that the fixed abrasive pad is used as the
polishing member in this embodiment, but the polishing tape can be
used as the polishing member like the first and second
embodiments.
Embodiment 4
[0050] A fourth embodiment according to the present invention will
now be explained. It is to be noted that a basic structure of a
polishing apparatus and a basic polishing method are the same as
those in the first embodiment, thereby omitting an explanation of
the particulars described in the first embodiment.
[0051] FIG. 7 is a view for explaining a polishing method according
to this embodiment.
[0052] In this embodiment, a polishing target surface at a
periphery portion of a semiconductor wafer 10 is polished while
moving a polishing region of a polishing tape (a polishing member)
41 in a circumferential direction of the semiconductor wafer 10.
For example, as shown in FIG. 7, polishing is carried out while
gradually moving a polishing head 60 in the circumferential
direction of the semiconductor wafer 10. It is to be noted that the
elastic member 31, the pressing heads 32, the shafts 33, and the
cylinders 34 in the polishing apparatus according to the first
embodiment substantially correspond to the polishing head 60, for
example. It is assumed that a movement angle .theta. (a maximum
movement angle from a movement center) of the polishing head 60 is
approximately, e.g., 3.degree. and a movement speed of the same is
approximately 0.3.degree./second. Since the polishing head 60 is
moved in the circumferential direction of the semiconductor wafer
10 in this manner, a region of the polishing tape 41 which is
pressed by the polishing head 60 moves, and a polishing region of
the polishing tape 41 (a range of a region used for polishing)
moves.
[0053] FIG. 8 is a view showing a polishing region 45 of the
polishing tape 41. Since the polishing head 60 moves in a vertical
direction to a movement direction of the polishing tape 41 (a tape
feed direction), the polishing region 45 moves in an oblique
direction.
[0054] As explained in the first embodiment, a width of a polishing
region of an end facet of the semiconductor wafer 10 is generally
narrower than a width of a polishing region of a slant surface of
the same. Therefore, when polishing the end facet, increasing the
movement angle .theta. of the polishing head 60 beyond the
counterpart when polishing the slant surface is desirable. As a
result, when polishing the end facet, the polishing tape 41 can be
effectively used in a width direction of the polishing tape 41.
Therefore, when polishing the end facet, the polishing tape 41 can
be used in a wide region, thereby decreasing an amount of using the
polishing tape 41.
[0055] It is to be noted that polishing can be carried out while
oscillating the polishing head 60. For example, when polishing the
end facet of the semiconductor wafer 10, the movement angle (an
oscillation angle) .theta. is set to approximately 3.degree., and
an oscillation speed is set to approximately 100 rpm. When
polishing the slant surface of the semiconductor wafer 10, the
movement angle (the oscillation angle) .theta. is set to
approximately 0.5.degree., and the oscillation speed is set to
approximately 150 rpm. In this case, the polishing tape 41 can be
used in a wide region, thus reducing an amount of using the
polishing tape 41.
[0056] Moreover, such a fixed abrasive pad as described in the
third embodiment may be used in place of the polishing tape. In
this case, the fixed abrasive pad is reciprocated in the
circumferential direction of the semiconductor wafer 10, and the
fixed abrasive pad is moved in a vertical direction to the
circumferential direction of the semiconductor wafer 10.
Consequently, as shown in FIG. 9, a polishing region (a range of a
region used for polishing) 45 of the fixed abrasive pad 42 moves in
a zigzag pattern. Therefore, the fixed abrasive pad 42 can be used
in a wide region.
[0057] It is to be noted that the method explained in this
embodiment can be appropriately applied to the polishing
apparatuses and the polishing methods described in the first to
third embodiments. Therefore, in this embodiment, the same effect
as the basic effect explained in the first to third embodiments can
be obtained.
[0058] Additionally, since polishing is performed while moving the
polishing region of the polishing member in the circumferential
direction of the semiconductor wafer in this embodiment, the
polishing member can be used in a wide region. Further, when the
polishing head or the polishing member is oscillated, the peak
positions in the pressure distribution explained in the first to
third embodiments move with oscillation, and hence the peak
positions in the pressure distribution can be averaged in terms of
time. Accordingly, a pressure can be prevented from being
concentrated on a specific position of the polishing member,
thereby averaging the pressure applied to the polishing member.
[0059] Incidentally, in each of the foregoing embodiments, as a
material of a polishing target film, there are, e.g., SiO.sub.2,
SiN, Si, poly-Si, a-Si, Hf, Al.sub.2O.sub.3, Ta, Ti, Ru, Al, W, Cu,
Ni, NiSi.sub.x, Co, CoSi.sub.x, and others.
[0060] Furthermore, as a base material of the polishing tape, there
are a resin film (e.g., PET or PPS) a nonwoven fabric, a fabric,
and others. As the abrasive, there are, e.g., diamond, SiC,
Al.sub.2O.sub.3, SiO.sub.2, Ceria, TiO.sub.2, and others.
[0061] Moreover, as a polishing type, there is polishing which is
of a free abrasive type (polishing using a slurry and a polishing
pad) as well as polishing which is of a fixed abrasive type
(polishing using the polishing tape or the fixed abrasive pad).
[0062] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
* * * * *