U.S. patent application number 11/057752 was filed with the patent office on 2005-07-07 for shower head of a wafer treatment apparatus having a gap controller.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Jo, Hye-jin, Kim, Dong-hyun, Kwon, O-ik, Park, Jong-chul.
Application Number | 20050145338 11/057752 |
Document ID | / |
Family ID | 36772450 |
Filed Date | 2005-07-07 |
United States Patent
Application |
20050145338 |
Kind Code |
A1 |
Park, Jong-chul ; et
al. |
July 7, 2005 |
Shower head of a wafer treatment apparatus having a gap
controller
Abstract
A shower head for adjusting distribution of a reactant gas in a
process region of a semiconductor manufacturing reaction chamber,
wherein a top plate has a gas port for introducing the reactant gas
into the reaction chamber; a face plate, having through holes,
disposed opposite the process region; a first baffle plate, having
through holes, disposed between the top plate and the face plate
and capable of moving up or down, wherein the first baffle plate
has a top surface that defines a first gap for forming a first
lateral flow passage; a second baffle plate, having through holes,
disposed between the first baffle plate and the face plate and
capable of moving up or down, wherein the second baffle plate has a
top surface that defines a second gap for forming a second lateral
flow passage; and a gap controller for determining widths of the
first and second gaps.
Inventors: |
Park, Jong-chul;
(Suwon-city, KR) ; Kim, Dong-hyun; (Seoul, KR)
; Kwon, O-ik; (Seoul, KR) ; Jo, Hye-jin;
(Anyang-city, KR) |
Correspondence
Address: |
LEE, STERBA & MORSE, P.C.
Attorneys and Counselors at Law
SUITE 2000
1101 WILSON BOULEVARD
ARLINGTON
VA
22209
US
|
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Suwon-city
KR
|
Family ID: |
36772450 |
Appl. No.: |
11/057752 |
Filed: |
February 15, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11057752 |
Feb 15, 2005 |
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10178757 |
Jun 25, 2002 |
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6872258 |
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Current U.S.
Class: |
156/345.34 |
Current CPC
Class: |
C23C 16/45589 20130101;
H01L 21/67017 20130101; C23C 16/45565 20130101 |
Class at
Publication: |
156/345.34 |
International
Class: |
C23F 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 16, 2001 |
KR |
01-42822 |
Claims
1-55. (canceled)
56. The shower head of claim 93, wherein the shower head supplies a
reactant gas to a process region within a reaction chamber, the
shower head further comprising: a top plate having a gas port for
introducing the reactant gas supplied from an outside source into
the reaction chamber; a face plate disposed opposite the process
region, the face plate having a plurality of through holes, the
first baffle plate being disposed between the top plate and the
face plate and the second baffle plate being disposed between the
first baffle plate and the face plate, the second baffle plate
having a top surface of the second baffle plate defining the gap
for forming a lateral flow passage of the reactant gas between the
first and second baffle plates; the plurality of piezoelectric
elements being disposed on the second baffle plate; and a power
supply unit for applying voltage to each of the plurality of
piezoelectric elements.
57. The shower head of claim 56, wherein each of the plurality of
piezoelectric elements comprises: a piezoelectric layer which
vibrates in a thickness extensional mode according to the
application of voltage, the piezoelectric layer having two main
surfaces; first and second electrode layers, each of which is
formed on one of the two main surfaces of the piezoelectric layer;
and an insulating layer formed on the first electrode layer
adjacent to the first baffle plate.
58. The shower head of claim 57, wherein the piezoelectric layer is
formed of one selected from the group consisting of lead zirconate
titanate (PZT), PbTiO.sub.3, BaTiO.sub.3, and poly vinylidene
fluoride (PVDF) polymer.
59. The shower head of claim 57, wherein the second electrode layer
is constructed by the second baffle plate.
60. The shower head of claim 56, wherein the plurality of
piezoelectric elements are formed at positions corresponding to
those at which the plurality of through holes of the first baffle
plate are formed.
61. The shower head of claim 56, wherein each of the plurality of
piezoelectric elements controls the amount of the reactant gas
flowing from the through holes of the first baffle plate into the
gap using a thickness expansion rate of the piezoelectric element
adjusted according to the level of voltage applied from the power
supply unit.
62. The shower head of claim 56, wherein each of the plurality of
piezoelectric elements selectively opens or closes the plurality of
through holes using a thickness expansion rate of the piezoelectric
element adjusted according to the level of voltage applied from the
supply unit.
63. The shower head of claim 56, wherein the plurality of through
holes of the first baffle plate are formed at a first position
spaced apart from a central axis of the first baffle plate by a
predetermined radius, and wherein one of the plurality of
piezoelectric elements includes an annular element formed at a
position corresponding to the first position on the second baffle
plate.
64. The shower head of claim 56, wherein the first and second
baffle plates are formed of aluminum.
65. The shower head of claim 56, further comprising a guide baffle
plate disposed on the first baffle plate coaxially with respect to
the first baffle plate, the guide baffle plate having a bottom face
opposing the first baffle plate, wherein an upper gap for providing
a lateral flow passage of the reactant gas is formed between the
guide baffle plate and the first baffle plate, and wherein the
guide baffle plate has an inlet for introducing the reactant gas
supplied through the top plate, and a plurality of outlets for
flowing the reactant gas introduced through the inlet out into the
upper gap through a plurality of passages.
66. The shower head of claim 65, wherein the plurality of outlets
formed in the guide baffle plate are formed at a position spaced
apart in a radial direction from a central axis of the guide baffle
plate by a predetermined distance.
67. The shower head of claim 56, further comprising a third baffle
plate disposed between the second baffle plate and the face baffle
plate, the third baffle plate having a plurality of through
holes.
68. The shower head of claim 67, wherein the third baffle plate is
formed of high resistance material whose resistivity is
sufficiently high to electrically stabilize the shower head.
69. The shower head of claim 68, wherein the third baffle plate is
formed of silicon carbide (SiC).
70-92. (canceled)
93. A shower head comprising: a first baffle plate having a
plurality of through holes; a second baffle plate disposed below
the first baffle plate with a gap having a predetermined width
interposed between the first and second baffle plates, the second
baffle plate having a plurality of through holes; and a plurality
of piezoelectric elements disposed between the first and second
baffle plates for controlling the amount of a reactant gas flowing
through the plurality of through holes formed in the first baffle
plate.
94. The shower head of claim 93, wherein the first baffle plate is
circular and the plurality of through holes formed in the first
baffle plate comprises: a plurality of first through holes formed
at a position spaced apart from a central axis of the first baffle
plate by a first radius; a plurality of second through holes formed
at a position spaced apart from the central axis of the first
baffle plate by a second radius greater than the first radius; and
a plurality of third through holes formed at a position spaced
apart from the central axis of the first baffle plate by a third
radius greater than the second radius.
95. The shower head of claim 94, wherein the second baffle plate is
circular and the plurality of through holes formed in the second
baffle plate comprises: a fourth through hole formed at a position
corresponding to a central axis of the second baffle plate; a
plurality of fifth through holes formed at a position spaced apart
from a central axis of the second baffle plate by a fourth radius;
a plurality of sixth through holes formed at a position spaced
apart from the central axis of the second baffle plate by a fifth
radius greater than the fourth radius; and a plurality of seventh
through holes formed at a position spaced apart from the central
axis of the second baffle plate by a sixth radius greater than the
fifth radius.
96. The shower head of claim 93, wherein each of the plurality of
piezoelectric elements is comprised of an annular element disposed
on the second baffle plate.
97. The shower head of claim 93, wherein the plurality of
piezoelectric elements are bonded to the second baffle plate.
98. The shower head of claim 94, wherein the plurality of
piezoelectric elements comprise: a first piezoelectric element
disposed at a position on the second baffle plate corresponding to
a position at which the plurality of first through holes of the
first baffle plate are formed; a second piezoelectric element
disposed at a position on the second baffle plate corresponding to
a position at which the plurality of second through holes of the
first baffle plate are formed; and a third piezoelectric element
disposed at a position on the second baffle plate corresponding to
a position at which the plurality of third through holes of the
first baffle plate are formed.
99. The shower head of claim 93, further comprising a power supply
unit for applying voltage to each of the plurality of piezoelectric
elements.
100. The shower head of claim 98, further comprising a power supply
unit for applying voltage to each of the first, second, and third
piezoelectric elements, wherein the power supply unit applies
different levels of voltage to each of the first, second, and third
piezoelectric elements.
101. The shower head of claim 98, further comprising a power supply
unit for applying voltage to the first piezoelectric element,
wherein the first piezoelectric element has a thickness expansion
rate that can be adjusted according to the level of voltage applied
from the power supply unit in order to control a distance between
the first through hole and the first piezoelectric element.
102. The shower head of claim 98, further comprising a power supply
unit for applying voltage to the second piezoelectric element,
wherein the second piezoelectric element has a thickness expansion
rate that can be adjusted according to the level of voltage applied
from the power supply unit in order to control a distance between
the plurality of second through holes and the second piezoelectric
element.
103. The shower head of claim 98, further comprising a power supply
unit for applying voltage to the third piezoelectric element,
wherein the third piezoelectric element has a thickness expansion
rate that can be adjusted according to the level of voltage applied
from the power supply unit in order to control a distance between
the plurality of third through holes and the third piezoelectric
element.
104. The shower head of claim 93, wherein the first and second
baffle plates are formed of aluminum.
105. The shower head of claim 93, wherein each of the plurality of
piezoelectric elements comprises: a piezoelectric layer which
vibrates in a thickness extensional mode according to the
application of voltage, the piezoelectric layer having two main
surfaces; first and second electrode layers, each of which is
formed on one of the two main surfaces of the piezoelectric layer;
and an insulating layer formed on the first electrode layer
adjacent to the first baffle plate.
106. The shower head of claim 105, wherein the piezoelectric layer
is formed of one selected from the group consisting of lead
zirconate titanate (PZT), PbTiO.sub.3, BaTiO.sub.3, and poly
vinylidene fluoride (PVDF) polymer.
107. The shower head of claim 105, wherein the second electrode
layer is constructed by the second baffle plate.
108. The shower head of claim 107, wherein each of the plurality of
piezoelectric element further comprises a bonding surface between
the piezoelectric layer and the second baffle plate.
Description
BACKGROUND OF-THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an apparatus for
manufacturing a semiconductor device. More particularly, the
present invention relates to a shower head provided to supply a
reactant gas using plasma to a reaction chamber in a wafer
treatment apparatus.
[0003] 2. Description of the Related Art
[0004] As the integration density of semiconductor devices
increases, a design rule decreases and the diameter of a wafer
increases. Large wafers often undergo multiple steps for
fabricating semiconductor devices, including, for example,
deposition processes for depositing material layers on a wafer or
etch processes for etching material layers on the wafer in a
predetermined pattern by supplying a reactant gas from the upper
portion of a reaction chamber for depositing or etching the wafer.
In particular, as wafer sizes increase, during etch processes, it
is important to optimize uniformity in etch rates over the entire
wafer surface.
[0005] In a typical etching apparatus, a reactant gas, which is
required for etching, is introduced into a reaction chamber by a
downstream method whereby the gas is supplied from an upper
electrode and pumped out into the periphery of a lower electrode.
In order to evenly distribute the reactant gas within the reaction
chamber, a shower head including several baffles, each of which has
a plurality of through holes, is installed at the upper part of the
reaction chamber. In a conventional shower head, the respective
positions of the through holes and a gap between the baffles are
fixed.
[0006] The function of the baffles provided in the shower head is
to control the distribution of a flow of gas within an upper
electrode, i.e., a gas distribution plate (GDP), of the etching
apparatus. Typically, a gas distribution function of the baffle is
determined by the gap between the baffles and an opening ratio of
the through holes formed in each of the baffles. However, since the
respective positions of the through holes provided in each baffle
and the gap between the baffles are fixed in the conventional
shower head, distribution in etch rates varies over the entire
wafer surface each time a process to be performed in an etching
apparatus is changed. Thus, the configuration of the conventional
shower head involves limitations in developing a new process.
Furthermore, development of a new etching apparatus usually
requires numerous simulation processes and significant expense.
[0007] For example, in the case of an etch process for forming a
gate electrode on a wafer, it may not be desirable to obtain
etching uniformity over the entire wafer surface during an etch
process step for forming an etch mask layer before gate patterning.
Furthermore, if an etch process including multiple steps is
performed, uniformity in etch rate on the wafer varies from one
step to another. However, in the conventional shower head in which
the respective positions of the through holes provided in each
baffle and the gap between the baffles are fixed, it is impossible
to supply different amounts of gas to different positions on the
wafer, thereby increasing the difficulty to optimize the uniformity
of a pattern to be formed over the entire wafer surface. Problems
associated with an unevenness in an etch rate during an etch
process during a fabrication process for a semiconductor device
adversely affect the performance of the device and yields.
SUMMARY OF THE INVENTION
[0008] In an effort to solve the above problems, it is a feature of
an embodiment of the present invention to provide a shower head
capable of controlling the distribution amount of a reactant gas
depending on a position on a wafer in order to obtain optimum
uniformity in etch rate over the entire wafer surface during a
fabrication process for a semiconductor device.
[0009] It is another feature of an embodiment of the present
invention to provide a shower head capable of controlling the
amount of a reactant gas supplied depending on a position on a
wafer as desired by compensating for degradation of etch rate
uniformity which may occur depending on the position on the wafer
during an etch step so that a final etch rate uniformity may be
optimized.
[0010] Accordingly, to provide the above features, the present
invention provides a shower head for controlling the distribution
amount of a reactant gas at a process region within a reaction
chamber. In a shower head according to a first aspect of the
present invention, a top plate has a gas port for introducing the
reactant gas supplied from an outside source into the reaction
chamber. A face plate, having a plurality of through holes, is
disposed opposite the process region. A first baffle plate, having
a plurality of through holes, is disposed between the top plate and
the face plate so that it is capable of moving up or down. The
first baffle plate has a top surface that defines a first gap for
forming a first lateral flow passage of the reactant gas. A second
baffle plate, having a plurality of through holes, is disposed
between the first baffle plate and the face plate so that it is
capable of moving up or down. The second baffle plate has a top
surface that defines a second gap for forming a second lateral flow
passage of the reactant gas between the first and second baffle
plates. A gap controller is used to determine the width of the
first gap and the width of the second gap.
[0011] Preferably, the plurality of through holes formed in the
first baffle plate includes a plurality of first through holes
formed at a first position which is proximate to a central axis of
the first baffle plate and spaced apart in a radial direction from
the central axis by a first distance; and a plurality of second
through holes formed at a second position which is proximate to an
edge of the first baffle plate and spaced apart in a radial
direction from the central axis by a second distance greater than
the first distance.
[0012] The gap controller preferably determines the position of the
first baffle plate to decrease the width of the first gap so that
the amount of the reactant gas flowing through the plurality of
first through holes is greater than the amount of the reactant gas
flowing through the plurality of second through holes.
[0013] The gap controller preferably determines the position of the
first baffle plate to increase the width of the first gap so that
the amount of the reactant gas flowing through the plurality of
second through holes is increased.
[0014] Furthermore, the gap controller preferably determines the
position of the second baffle plate to increase the width of the
second gap so that the amount of the reactant gas flowing through
the plurality of through holes formed in the second baffle plate is
made uniform over the entire process region.
[0015] The gap controller preferably determines the position of the
second baffle plate to decrease the width of the second gap so that
the amount of the reactant gas flowing through the plurality of
through holes formed in the second baffle plate is selectively made
to vary depending on a position in the process region.
[0016] In the shower head according to the first aspect of the
present invention, the gap controller may include a first spacer
ring disposed on top of the first baffle plate for determining the
width of the first gap; and a second spacer ring disposed between
the first and second baffle plates for determining the width of the
second gap. The first spacer ring may be disposed on a top edge of
the first baffle plate, and the second spacer ring may be disposed
on a top edge of the second baffle plate. The first and second
spacer rings may be composed of one or more annular rings.
Preferably, at least one of the first and second spacer rings may
have an annular contact portion in which a plurality of sawtooth
gears are formed. Each of the plurality of sawtooth gears may have
a pitch corresponding to the length of an arc of a central angle
90.degree.. Additionally, the height of each sawtooth gear of the
annular contact portion is in the range of approximately 0.01-0.5
mm. The first spacer ring may have an annular contact portion
comprised of a plurality of sawtooth gears formed opposite the
first baffle plate. In this case, the first baffle plate includes a
spacer ring coupler having a plurality of sawtooth gears formed
opposite the first spacer ring to mesh with the plurality of
sawtooth gears of the annular contact portion. The first spacer
ring may have an annular contact portion including a plurality of
sawtooth gears formed opposite the first baffle plate, and the
first baffle plate may include a spacer ring coupler having a
plurality of sawtooth gears formed opposite the first spacer ring
to mesh with the plurality of sawtooth gears of the annular contact
portion.
[0017] Alternatively, the second spacer ring may have an annular
contact portion comprised of a plurality of sawtooth gears formed
opposite the second baffle plate. In this case, the second baffle
plate comprises a spacer ring coupler having a plurality of
sawtooth gears formed opposite the second spacer ring to mesh with
the plurality of sawtooth gears of the annular contact portion.
[0018] In the shower head according to the first aspect of the
present invention, the first baffle plate may include a single
disk-type element having a uniform thickness over the entire
surface.
[0019] In the shower head according to the first aspect of the
present invention, the first baffle plate may include a disk-like
base plate having a plurality of through holes and a groove for
providing a circular space at the center of a top surface thereof;
and a disk-like insert plate inserted to rotate about a central
axis of the first baffle plate within the groove, the disk-like
insert plate having a plurality of through holes that are in
communication with selected ones of the plurality of through holes
formed in the base plate.
[0020] The plurality of through holes formed in the base plate may
include: a plurality of first through holes formed at a first
position that is proximate to the central axis of the first baffle
plate and spaced apart in a radial direction from the central axis
by a first distance less than a radius of the insert plate; and a
plurality of second through holes formed at a second position that
is proximate to an edge of the base plate and spaced apart in a
radial direction from the central axis by a second distance greater
than the radius of the insert plate. The plurality of first through
holes are in communication with the plurality of through holes
formed in the insert plate depending on rotational distance of the
insert plate. In order to change the opening ratio of the first
through hole depending on the rotational distance of the insert
plate, the plurality of through holes in the insert plate and the
plurality of first through holes in the base plate may be formed
selectively only in some angular ranges with respect to the central
axis of the first baffle plate.
[0021] The shower head according to the first aspect of the present
invention may further include a guide baffle plate disposed on the
first baffle plate coaxially with respect to the first baffle
plate, the guide baffle plate having an inlet for introducing the
reactant gas supplied through the top plate and a plurality of
outlets for flowing the reactant gas introduced through the inlet
out into the first gap through a plurality of passages. In this
case, the width of the first gap is defined by a bottom of the
guide baffle plate and a top surface of the first baffle plate. The
plurality of outlets formed in the guide baffle plate may be formed
at a position spaced apart in a radial direction from a central
axis of the guide baffle plate by a predetermined distance.
[0022] In the shower head including the guide baffle plate, the
plurality of through holes may include: a plurality of first
through holes formed at a first position which is proximate to a
central axis of the first baffle plate and spaced apart in a radial
direction from the central axis by a first distance; and a
plurality of second through holes formed at a second position which
is proximate to an edge of the first baffle plate and spaced apart
in a radial direction from the central axis by a second distance
greater than the first distance. The plurality of outlets formed in
the guide baffle plate are formed at a position that is spaced
apart in a radial direction from the central axis of the guide
baffle plate by a third distance greater than the first distance
and less than the second distance. Preferably, a distance between
each of the plurality of outlets and each of the plurality of first
through holes is less than a distance between each of the plurality
of outlets and each of the plurality of second through holes.
[0023] Furthermore, in the shower head including the gate baffle
plate, the gap controller may include a first spacer ring disposed
between the guide baffle plate and the first baffle plate for
determining the width of the first gap; and a second spacer ring
disposed between the first and second baffle plates for determining
the width of the second gap.
[0024] In the shower head according to the first aspect of the
present invention, the gap controller may include a first driving
shaft for selectively moving the guide baffle plate upwardly or
downwardly in order to determine the width of the first gap; and a
second driving shaft for selectively moving the first baffle plate
upwardly or downwardly in order to determine the width of the
second gap. The first driving shaft may be coaxially installed with
the second driving shaft.
[0025] In the shower head according to the first aspect of the
present invention, the gap controller may include an elevating
mechanism for moving the first baffle plate upwardly or downwardly
using a first stepping motor in order to determine the width of the
second gap; and a rotating mechanism for moving the guide baffle
plate upwardly or downwardly by a gear drive using a second
stepping motor in order to determine the width of the first gap.
The elevating mechanism is integrated with the rotating
mechanism.
[0026] The elevating mechanism may comprise a shaft, which extends
to pass through the guide baffle plate and the first baffle plate,
and an outward flange disposed at one end of the shaft for moving
the first baffle plate upwardly or downwardly to follow the upward
or downward movement of the shaft. The rotating mechanism includes
the shaft which is rotatable by power transmitted from the second
stepping motor, and an external screw formed on an outer
circumference of the shaft where the guide baffle plate is
combined, for raising or lowering the guide baffle plate according
to the rotation of the shaft. A circular space for housing the
outward flange formed at the end of the shaft may be formed at the
central portion of the first baffle plate. The circular space
accommodates the outward flange without friction so that the
rotation of the outward range does not affect the first baffle
plate when the shaft is rotated by the rotating mechanism in order
to raise or lower the guide baffle plate. A central hole, through
which the shaft passes, may be formed at a central portion of the
guide baffle plate, and an internal thread mating with the external
thread of the screw of the shaft is formed on an inner wall of the
central hole. The internal thread mating with the external thread
of the screw may be formed in the guide baffle plate so that the
guide baffle plate is moved upwardly or downwardly to follow the
movement of the shaft when the shaft is moved up or down by the
elevating mechanism in order to raise or lower the first baffle
plate. The shower head may further include a stopper for preventing
the guide baffle plate from rotating when the shaft is rotated by
the rotating mechanism.
[0027] The shower head according to the first aspect of the present
invention may be configured so that the first baffle plate contacts
the second baffle plate so that selected ones of the plurality of
through holes formed in the first baffle plate are in communication
with selected ones of the plurality of through holes formed in the
second baffle plate to thereby form align holes. The shower head
may further include a rotating mechanism connected to the first
baffle plate so that the first baffle plate rotates with respect to
the second baffle plate in a predetermined angular range. The
plurality of through holes formed in the first baffle plate are
distributed to have different opening ratios depending on a radius
from the central axis of the first baffle plate. The plurality of
through holes formed in the second baffle plate are distributed to
have different opening ratios depending on the distance by which
the first baffle plate rotates about the central axis of the second
baffle plate. The rotating mechanism changes the rotational
distance of the first baffle plate in order to change the opening
position of the align holes. The first baffle plate may be divided
into a plurality of sectorial regions that extend in a radial
direction from the central axis thereof, each sectorial region
having a plurality of through holes formed only in a predetermined
range spaced apart from the central axis by a selected radius. The
second baffle plate may be divided into a plurality of sectorial
regions that extend in a radial direction from the central axis
thereof, and the plurality of sectorial regions having the
plurality of through holes are arranged at regular intervals. In
this configuration, the gap controller may include a driving shaft
for simultaneously moving the first and second baffle plates
upwardly or downwardly in order to determine the width of the first
gap. The width of the second gap may be effectively zero.
[0028] In a shower head according to a second aspect of the present
invention, a top plate has a gas port for introducing the reactant
gas supplied from an outside source into the reaction chamber. A
face plate, having a plurality of through holes, is disposed
opposite the process region. A first baffle plate, having a
plurality of through holes, is disposed between the top plate and
the face plate. A second baffle plate, having a plurality of
through holes, is disposed between the first baffle plate and the
face plate.
[0029] In addition, the second baffle plate has a top surface that
defines a gap for forming a lateral flow passage of the reactant
gas between the first and second baffle plates. A plurality of
piezoelectric elements are disposed on the second baffle plate for
controlling the amount of the reactant gas through the gap. A power
supply unit applies voltage to each of the plurality of
piezoelectric elements.
[0030] Each of the plurality of piezoelectric elements may include
a piezoelectric layer which vibrates in a thickness extensional
mode according to the application of voltage, the piezoelectric
layer having two main surfaces; first and second electrode layers,
each of which is formed on one of the two main surfaces of the
piezoelectric layer; and an insulating layer formed on the first
electrode layer adjacent to the first baffle plate. The second
electrode layer is constructed by the second baffle plate.
[0031] The plurality of piezoelectric elements may be formed at
positions corresponding to those at which the plurality of through
holes of the first baffle plate are formed.
[0032] Each of the plurality of piezoelectric elements may control
the amount of the reactant gas flowing from the through holes of
the first baffle plate into the gap using a thickness expansion
rate of the piezoelectric element adjusted according to the level
of voltage applied from the power supply unit. Also, each of the
plurality of piezoelectric elements may selectively open or close
the plurality of through holes using a thickness expansion rate of
the piezoelectric element adjusted according to the level of
voltage applied from the supply unit.
[0033] The plurality of through holes of the first baffle plate may
be formed at a first position spaced apart from a central axis of
the first baffle plate by a predetermined radius. One of the
plurality of piezoelectric elements includes an annular element
formed at a position corresponding to the first position on the
second baffle plate.
[0034] The shower head according to the second aspect of the
present invention may further include a third baffle plate disposed
between the second baffle plate and the face plate, the third
baffle plate having a plurality of through holes. The third baffle
plate may be formed of high resistance material whose resistivity
is sufficiently high to electrically stabilize the shower head.
[0035] In the shower head according to a third aspect of the
present invention, a first baffle plate has a plurality of first
and second through holes in order to selectively adjust the amount
of the reactant gas supplied from an outside source according to a
radius from the central axis. The plurality of first through holes
are spaced apart from a central axis by a first radius and the
plurality of second through holes are spaced apart from the central
axis by a second radius. A second baffle plate, having a plurality
of through holes, is disposed below the first baffle plate so that
a gap for providing a lateral flow passage is formed between the
first and second baffle plates. A gap controller moves at least one
of the first and second baffle plates in order to adjust the width
of the gap.
[0036] Preferably, the gap controller may include a spacer ring
having a predetermined thickness disposed between the first and
second baffle plates for determining the width of the gap. The
spacer ring is composed of one or more annular rings.
[0037] The spacer ring may be configured to have an annular contact
portion in which a plurality of sawtooth gears are formed. Each of
the plurality of sawtooth gears may have a pitch corresponding to
the length of an arc of a central angle 90.degree.. The annular
contact portion of the spacer ring may contact a bottom surface of
the first baffle plate. In this case, a spacer ring coupler having
a plurality of sawtooth gears formed to mesh with the plurality of
sawtooth gears of the annular contact portion is formed on the edge
of the bottom surface of the first baffle plate. The space ring
coupler of the first baffle plate may have a portion having a
thickness less than a thickness of a bottom central portion of the
first baffle plate. Alternatively, the annular contact portion of
spacer ring may contact a top surface of the second baffle plate. A
spacer ring coupler having a plurality of sawtooth gears formed to
mesh with the plurality of sawtooth gears of the annular contact
portion is formed on the top surface of the second baffle plate.
Preferably, the spacer ring coupler of the second baffle plate has
a portion having a thickness less than a thickness of a top central
portion of the second baffle plate.
[0038] In a shower head according to a fourth aspect of the present
invention, a circular first baffle plate has a plurality of through
holes. A circular second baffle plate, having a plurality of
through holes, is disposed below the first baffle plate with a gap
having a predetermined width interposed between the first and
second baffle plates. A plurality of piezoelectric elements are
disposed between the first and second baffle plates for controlling
the amount of a reactant gas flowing through the plurality of
through holes formed in the first baffle plate.
[0039] The plurality of through holes formed in the first baffle
plate may include a plurality of first through holes formed at a
position spaced apart from a central axis of the first baffle plate
by a first radius; a plurality of second through holes formed at a
position spaced apart from the central axis of the first baffle
plate by a second radius greater than the first radius; and a
plurality of third through holes formed at a position spaced apart
from the central axis of the first baffle plate by a third radius
greater than the second radius.
[0040] The plurality of through holes formed in the second baffle
plate may include: a fourth through hole formed at a position
corresponding to a central axis of the second baffle plate; a
plurality of fifth through holes formed at a position spaced apart
from a central axis of the second baffle plate by a fourth radius;
a plurality of sixth through holes formed at a position spaced
apart from the central axis of the second baffle plate by a fifth
radius greater than the fourth radius; and a plurality of seventh
through holes formed at a position spaced apart from the central
axis of the second baffle plate by a sixth radius greater than the
fifth radius.
[0041] Each of the plurality of piezoelectric elements may include
an annular element disposed on the second baffle plate. Preferably,
the plurality of piezoelectric elements are bonded to the second
baffle plate.
[0042] The plurality of piezoelectric elements may include a first
piezoelectric element disposed at a position on the second baffle
plate corresponding to a position at which the plurality of first
through holes of the first baffle plate are formed; a second
piezoelectric element disposed at a position on the second baffle
plate corresponding to a position at which the plurality of second
through holes of the first baffle plate are formed; and a third
piezoelectric element disposed at a position on the second baffle
plate corresponding to a position at which the plurality of third
through holes of the first baffle plate are formed.
[0043] The shower head according to the fourth aspect of the
present invention may further include a power supply unit for
applying voltage to each of the plurality of piezoelectric
elements. Each piezoelectric element has a thickness expansion rate
that may be adjusted according to a varying level of voltage
applied from the power supply unit.
[0044] According to the present invention, the width of the gap is
selectively decreased or increased by the gap controller, thereby
adjusting the amount of reactant gas supplied in accordance with a
position on a wafer in a process region of a reaction chamber and
making the amount of the reactant gas supplied to a position on the
wafer even or uneven depending on the type of application. Thus,
according to the present invention, it is easier to adjust the
distribution of the reactant gas depending on a position on the
wafer in order to obtain optimized etch rate uniformity over the
entire wafer surface during the fabrication process of a
semiconductor device. Furthermore, the present invention makes it
possible to freely adjust the amount of reactant gas supplied,
thereby compensating in advance for degradation in etch rate
uniformity that may partially occur on the wafer during an etch
step.
[0045] These and other features and aspects of the present
invention will be readily apparent to those of ordinary skill in
the art upon review of the detailed description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] The above features and advantages of the present invention
will be readily apparent to those of ordinary skill in the art upon
review of the detailed description that follows with reference to
the attached drawings in which:
[0047] FIG. 1 illustrates a cross-sectional view schematically
showing a configuration of a shower head according to a first
embodiment of the present invention;
[0048] FIG. 2 illustrates a top view of a face plate provided in
the shower head according to the first embodiment of the present
invention;
[0049] FIG. 3 illustrates a top view of a first baffle plate
provided in the shower head according to the first embodiment of
the present invention;
[0050] FIG. 4 illustrates a top view of a second baffle plate
provided in the shower head according to the first embodiment of
the present invention;
[0051] FIGS. 5A-5C illustrate a guide baffle plate provided in the
shower head according to the first embodiment of the present
invention;
[0052] FIG. 6 illustrates the relationship among the positions of
through holes formed in a guide baffle plate, a first baffle plate,
and a second baffle plate.
[0053] FIG. 7 illustrates a top view of a third baffle plate
provided in a shower head according to the first embodiment of the
present invention;
[0054] FIG. 8 illustrates a perspective view of an annular ring
that is an example of a gap controller adopted in a shower head
according to an embodiment of the present invention;
[0055] FIGS. 9A and 9B illustrate an annular ring that is another
example of a gap controller adopted in a shower head according to
an embodiment of the present invention;
[0056] FIG. 10 illustrates a top view of an example of a modified
first baffle plate that can be adopted in a shower head according
to an embodiment of the present invention;
[0057] FIG. 11 illustrates a top view of a modified second baffle
plate that can be adopted in a shower head according to an
embodiment of the present invention;
[0058] FIGS. 12A and 12B illustrate a method for controlling the
width of a second gap using the annular ring of FIG. 9A;
[0059] FIGS. 13A and 13B illustrates cross-sectional views taken
along line 13A-13A of FIG. 11;
[0060] FIGS. 14A and 14B illustrate a cross-sectional view and a
perspective view of another example of a modified first baffle
plate that can be adopted in a shower head according to an
embodiment of the present invention, respectively;
[0061] FIG. 15 schematically illustrates the configuration of main
parts of a shower head according to a second embodiment of the
present invention;
[0062] FIGS. 16A-16C schematically illustrate the configuration of
main parts of a shower head according to a third embodiment of the
present invention;
[0063] FIG. 17 schematically illustrates the configuration of main
parts of a shower head according to a fourth embodiment of the
present invention;
[0064] FIG. 18 illustrates a top view of the first baffle plate
included in the shower head of FIG. 17;
[0065] FIG. 19 illustrates a top view of the second baffle plate
included in the shower head of FIG. 17;
[0066] FIGS. 20A-20C illustrate views of a bottom of the second
baffle plate when the first and second baffle plates included in
the shower head of FIG. 17 contact each other with different
rotational distances;
[0067] FIG. 21 illustrates a cross-sectional view showing the
configuration of main parts of a shower head according to a fifth
embodiment of the present invention;
[0068] FIG. 22 illustrates a top view of the first baffle plate
included in the shower head of FIG. 21;
[0069] FIG. 23 illustrates a top view of the second baffle plate
included in the shower head of FIG. 21; and
[0070] FIG. 24 illustrates an enlarged view of the portion "A" of
FIG. 21.
DETAILED DESCRIPTION OF THE INVENTION
[0071] Korean Patent Application No. 2001-42822, filed on Jul. 16,
2001, and entitled: "Shower Head of Wafer Treatment Apparatus
Having Gap Controller," is incorporated by reference herein in its
entirety.
[0072] FIG. 1 illustrates a cross-sectional view schematically
showing the configuration of a shower head according to a first
embodiment of the present invention used for supplying a reactant
gas to a process region within a reaction chamber in order to
perform plasma etching on a wafer. Referring to FIG. 1, the shower
head according to the first embodiment includes a top plate 10 in
which a gas port 12 for introducing a reactant gas supplied from an
outside source into the reaction chamber is formed, and a face
plate 20 disposed opposite the process region within the reaction
chamber. The top plate 10 forms an upper wall of the reaction
chamber.
[0073] Referring to FIG. 2, which illustrates a view of the face
plate 20 when viewed from the process region of the reaction
chamber, a plurality of through holes 22 are uniformly formed in
the face plate 20.
[0074] Returning to FIG. 1, first and second baffle plates 30 and
40 are disposed coaxially with respect to the face plate 20 between
the top plate 10 and the face plate 20. A gap controller including
a first spacer ring 92 is disposed on the top surface of the first
baffle plate 30, and a gap controller including a second spacer
ring 94 is disposed between the first and second baffle plates 30
and 40. The first and second baffle plates 30 and 40 can be moved
up or down by controlling the thicknesses of the first and second
spacer rings 92 and 94, thereby determining the relative positions
of the first and second baffle plates 30 and 40. The movement of
the first and second baffle plates 30 and 40 will be described
below in greater detail.
[0075] The first baffle plate 30 is formed of a single disk-type
element having a uniform thickness over the entire surface thereof.
A plurality of first through holes 32 and a plurality of second
through holes 34 are formed in the first baffle plate 30, as shown
in FIG. 3. The plurality of first through holes 32 are formed at a
first position which is proximate to the central axis 31 of the
first baffle plate 30 and separated in a radial direction from the
central axis 31 by a first distance d.sub.1. The plurality of
second through holes 34 are formed at a second position which is
proximate to an edge of the first baffle plate 30 and separated in
a radial direction from the central axis 31 thereof by a second
distance d.sub.2 greater than the first distance d.sub.1. As shown
in FIG. 4, a plurality of through holes 42 are formed in uniform
density over the entire surface of the second baffle plate 40. The
first and second baffle plates 30 and 40 may be formed of
aluminum.
[0076] As shown in FIG. 1, a guide baffle plate 50 is disposed
coaxially with respect to the first baffle plate 30 on the first
baffle plate 30. The configuration of the guide baffle plate 50 are
schematically shown in FIGS. 5A-5C. Referring to FIGS. 5A-5C, one
inlet 52 through which a reactant gas enters the guide baffle plate
50 is formed on a top surface 50a of the guide baffle plate 50. The
reactant gas, which is introduced into the guide baffle plate 50
through the inlet 52, flows through a plurality of paths 53 to a
plurality of outlets 54 formed on a bottom 50b of the guide baffle
plate 50.
[0077] In the thus-configured shower head, as shown in FIG. 1, a
first gap 70 creating a first lateral flow path of a reactant gas
introduced into the reaction chamber is formed between the first
baffle plate 30 and the guide baffle plate 50. The width of the
first gap 70 is limited by the bottom 50b of the guide baffle plate
50 and the top surface of the first baffle plate 30. Furthermore, a
second gap 80 creating a second lateral flow path of the reactant
gas is formed between the first and second baffle plates 30 and 40.
The width of the second gap 80 is limited by the bottom of the
first baffle plate 30 and the top surface of the second baffle
plate 40.
[0078] FIG. 6 illustrates a position relationship among the through
holes 54, 32 and 34, and 42 respectively formed on the guide baffle
plate 50, the first baffle plate 30, and the second baffle plate
40. Referring to FIG. 6, the plurality of outlets 54 are formed at
a position on the guide baffle plate 50, which is separated in a
radial direction from a central axis 51 of the guide baffle plate
by a third distance d.sub.3. The third distance d.sub.3 is greater
than the first distance d.sub.1, by which the first through holes
32 are separated from the central axis 51 of the guide baffle plate
50, and less than the second distance d.sub.2, by which the second
through holes 34 are separated from the same axis 51. Preferably, a
distance between the outlet 54 of the guide baffle plate 50 and the
first through hole 32 of the first baffle plate 30 is less than
that between the outlet 54 and the second through hole 34. This
makes it possible to selectively control the amount of gas so that
the amount of gas flowing into the first through holes 32 is
greater than the amount of gas flowing into the second through
holes 34 or that the flow amount at the first and second through
holes 32 and 34 are kept constant by adjusting the width of the
first gap 70 formed between the guide baffle plate 50 and the first
baffle plate 30. That is, since the outlet 54 is closer to the
first through holes 32, it is easier to introduce a reactant gas
from the outlet 54 into the first through holes 32 as the first gap
70 becomes narrower, so that the amount of gas flowing through the
first through holes 32 is greater than the amount of gas flowing
through the second through holes 34. Thus, a greater amount of
reaction gas can be supplied to a central portion on the wafer than
to an edge thereof. On the other hand, as the width of the first
gap 70 increases, the amount of a reaction gas discharged and
diffused to the second through holes 34 through the outlet 54
increases, thus increasing the amount of reaction gas flowing
through the second through holes 34.
[0079] In order to electrically stabilize the shower head, a third
baffle plate 60 is disposed between the second baffle plate 40 and
the face plate 20. The third baffle plate 60 may be formed of high
resistance material whose resistivity is sufficiently high to
electrically stabilize the shower head, for example, silicon
carbide (SiC). As shown in FIG. 7, a plurality of through holes 62
are formed in uniform density over the entire surface of the third
baffle plate 60.
[0080] The width of the first gap 70 is determined by the first
spacer ring 92, which is the gap controller disposed on the top
edge of the first baffle plate 30 between the guide baffle plate 50
and the first baffle plate 30. The width of the second gap 80 is
determined by the second spacer ring 94, which is the gap
controller disposed on the top edge of the second baffle plate 40
between the first and second baffle plates 30 and 40.
[0081] FIG. 8 illustrates a perspective view of an annular ring 90,
which is an implementation example of the first or second spacer
ring 92 or 94. The thickness of the first or second spacer ring 92
or 94 is determined by the thickness t of the annular ring 90. In
order to adjust the widths of the first and second gaps 70 and 80
to a desired extent, the first or second spacer rings 92 and 94 may
include only one annular ring 90 having a desired thickness, or two
or more annular rings 90 having a predetermined thickness that
overlap one another by a desired thickness.
[0082] The position of the first baffle plate 30 and the width of
the first gap 70 may be determined by the thickness of the first
spacer ring 92. As the width of the first gap 70 decreases, the
amount of reaction gas passing through the first through holes 32
is greater than the amount of reaction gas passing through the
second through holes 34 in the first baffle plate 30. Conversely,
as the width of the first gap 70 increases, the amount of reaction
gas passing through the second through holes 34 in the first baffle
plate 30 is increased.
[0083] Furthermore, the width of the second gap 80 formed between
the first and second baffle plates 30 and 40 is determined by the
thickness of the second spacer ring 94. As the width of the second
gap 80 decreases, the amount of reaction gas passing through the
through holes 42 positioned near the first or second through holes
32 or 34 of the first baffle plate 30 among the plurality of
through holes 42 is increased, thereby making the amount of
reaction gas passing through the plurality of through holes 42
selectively uneven depending on a position within the process
region. Conversely, as the width of the second gap 80 increases to
a sufficient extent, the amount of reaction gas passing through the
plurality of through holes 42 may be made uniform over the entire
process region.
[0084] FIG. 9A illustrates a perspective view of an annular ring
190 having an annular contact portion 194 in which a plurality of
sawtooth gears 192 are formed, which is another implementation
example of the first or second spacer ring 92 or 94. FIG. 9B
illustrates a side view of the annular ring 190 taken along its
full length between 9B-9B of FIG. 9A.
[0085] Referring to FIGS. 9A and 9B, the sawtooth gears 192 are
designed to have a pitch that is the same as the length l of an arc
of a central angle (.theta.) 90.degree.. The height h of the
sawtooth gears 192 formed on the annular contact portion 194 is on
the order of approximately 0.01-0.5 mm.
[0086] If the first spacer ring 92 in the first gap 70 is comprised
of the annular ring 190, the annular contact portion 194 on which
the plurality of sawtooth gears 192 are formed may be disposed
opposite the first baffle plate 30 or the guide baffle plate 50. If
the annular contact portion 194 is disposed opposite the first
baffle plate 30 within the first gap 70, a spacer ring coupler
meshing with the sawtooth gear 192 is formed on the surface of the
first baffle plate 30 opposite the first spacer ring 92 comprised
of the annular ring 190.
[0087] FIG. 10 illustrates a modified first baffle plate 130 on
which a spacer ring coupler 132 for connecting with the annular
contact portion 194 has been formed. A plurality of sawtooth gears
(not shown) that mesh with the plurality of sawtooth gears 192 of
the annular contact portion 194 are formed on the spacer ring
coupler 132. Like in the annular ring 190, the sawtooth gears
formed on the spacer ring coupler 132 are designed to have a pitch
that is the same as the length of an arc of a central angle
90.degree.. The height of the sawtooth gears formed on the spacer
ring coupler 132 is on the order of approximately 0.01-0.5 mm.
[0088] Furthermore, if the second spacer ring 94 in the second gap
80 is comprised of the annular ring 190, the annular contact
portion 194 on which the plurality of sawtooth gears 192 are formed
may be disposed opposite the first or second baffle plate 30 or 40.
If the annular contact portion 194 is disposed opposite the second
baffle plate 40 within the second gap 80, a spacer ring coupler
meshing with the sawtooth gear 192 is formed on the surface of the
second baffle plate 40 opposite the second spacer ring 94 comprised
of the annular ring 190.
[0089] FIG. 11 illustrates a modified second baffle plate 140 on
which the spacer ring coupler 142 for connecting with the annular
contact portion 194 has been formed. A plurality of sawtooth gears
(not shown) that mesh with the plurality of sawtooth gears 192 of
the annular contact portion 194 are formed on the spacer ring
coupler 142. Like in the annular ring 190, the sawtooth gears
formed on the spacer ring coupler 142 are designed to have a pitch
that is the same as the length of an arc of a central angle
90.degree.. The height of the sawtooth gears formed on the spacer
ring coupler 142 is on the order of approximately 0.01-0.5 mm.
[0090] FIGS. 12A and 12B illustrate partial diagrammatic views of a
shower head for explaining a method for controlling the width of
the second gap 80 using the annular ring 190 when the second spacer
ring 94 disposed between the first baffle plate 30 and the modified
second baffle plate 140 is comprised of the annular ring 190. FIG.
12A illustrates a state in which the second gap 80 has the smallest
width. If the annular ring 190 rotates in a direction indicated by
arrow `a` or the modified second baffle plate 140 rotates in a
direction indicated by arrow `b` in the state shown in FIG. 12A,
the width of the second gap 80 is increased by .DELTA.w according
to its rotation distance, as shown in FIG. 12B. Thus, the width of
the second gap 80 is adjusted to a desired extent by controlling
the rotation distance of the annular ring 190 or the modified
second baffle plate 140.
[0091] FIGS. 13A and 13B illustrates cross-sectional views taken
along line 13A-13A of FIG. 11 for explaining the spacer ring
coupler 142 of the modified second baffle plate 140. Referring to
FIG. 13A, a low stepped portion 142a of the spacer ring coupler 142
on the modified second baffle plate 140, at which adjacent two saw
tooth gears meet each other, is thinner than a top central portion
140a of the modified second baffle plate 140. Referring to FIG.
13B, a highest toothed portion 142b of each saw tooth gear of the
spacer ring coupler 142 on the modified second baffle plate 140 is
thicker than the top central portion 140a of the modified second
baffle plate 140.
[0092] In order to control the width of the second gap 80 using the
annular ring 190, if the annular contact portion 194 of the annular
ring 190 is disposed opposite the first baffle plate 30, a spacer
ring coupler having the same configuration as the spacer ring
coupler 142 formed on the top edge of the modified second baffle
plate 140 is formed on a bottom edge of the first baffle plate 30.
Explanation of the detailed configuration of the spacer ring
coupler will be omitted since it is similar to that of the spacer
ring coupler 142 of the modified second baffle plate 140. The
difference is that if the annular contact portion 194 of the
annular ring 190 is disposed opposite the first baffle plate 30,
the annular contact portion 194 contacts the bottom of the first
baffle plate 30 and the spacer ring coupler of the first baffle
plate 30 has a portion with a thickness less than the thickness of
a bottom central portion of the first baffle plate 30.
[0093] Although the present invention has been described with
respect to the controlling of the width of the second gap 80 using
the annular ring 190, it will be understood by those of ordinary
skill in the art that the above configurations or arrangements may
be applied in the same manner to the controlling of the width of
the first gap 70 using the annular ring 190.
[0094] In the above embodiment, the first baffle plate 30 is formed
of a single disk-type element having a uniform thickness over the
entire surface. However, the first baffle plate 30 may be
configured in various ways depending on the type of
application.
[0095] FIGS. 14A and 14B illustrate a configuration of a modified
first baffle plate 230. FIG. 14A illustrates a cross-sectional view
taken along a central axis 231 of the modified first baffle plate
230. FIG. 14B illustrates an exploded perspective view of the
modified first baffle plate 230.
[0096] Referring to FIGS. 14A and 14B, the modified first baffle
plate 230 includes a disk-like base plate 232 having a groove 236
for providing a circular space at the center of the top surface
thereof, and a disk-like insert plate 234 inserted into the groove
236 so that it can rotate about the central axis 231 of the
modified first baffle plate 230 within the groove 236. The insert
plate 234 is connected to a driving device (not shown) for rotating
the insert plate 234 at a predetermined angle. The base plate 232
has a plurality of first through holes 237 and a plurality of
second through holes 238. The plurality of first through holes 237
are formed at a first position which is in close proximity to the
central axis 231 of the modified first baffle plate 230 and
separated in a radial direction from the central axis 231 by a
first distance d.sub.1 less than the radius of the insert plate
234. The plurality of second through holes 238 are formed at a
second position which is in close proximity to an edge of the base
plate 232 and separated in a radial direction from the central axis
231 by a second distance d.sub.2 greater than the radius of the
insert plate 234. The insert plate 234 has a plurality of through
holes 235 that may be in communication with the plurality of first
through holes 237 formed on the base plate 232. In order to change
the opening ratio of the first through holes 237 depending on
rotational distance of the insert plate 234, the plurality of
through holes 235 in the insert plate 234 and the plurality of
first through holes 237 in the base plate 232 are formed
selectively only in some angular ranges with respect to the central
axis 231 of the modified first baffle plate 230. That is, all or
some of the through holes 235 formed in the insert plate 234 may be
in communication with the first through holes 237 formed in the
base plate 232 depending on the rotational distance of the insert
plate 234.
[0097] By adopting the modified first baffle plate 230 having the
configuration as described above, the opening ratio of the first
through holes 237 formed on the base plate 232 is changed depending
on the rotation distance of the insert plate 234, thereby adjusting
the amount of reactant gas supplied from the process region of the
reaction chamber to a central portion on the wafer.
[0098] FIG. 15 schematically illustrates a configuration of main
parts of a shower head according to a second embodiment of the
present invention. The second embodiment is similar to the first
embodiment except for the fact that first and second driving shafts
292 and 294 are used as a gap controller for determining the first
and second gaps 70 and 80. In the embodiment shown in FIG. 15, the
gap controller includes first and second driving shafts 292 and
294. The first driving shaft 292 selectively moves the guide baffle
plate 50 up or down in order to determine the width of the first
gap 70. The second driving shaft 294 selectively moves the first
baffle plate 30 up or down in order to determine the width of the
second gap 80. The second driving shaft 294 is disposed coaxially
with respect to the first driving shaft 292. The distance by which
the guide baffle plate 50 or the first baffle plate 30 is moved up
or down is adjusted relative to each other, thereby determining the
width of the first or second gap 70 or 80. The width of the first
or second gap 70 or 80 is determined by considering the amount of a
reaction gas to be supplied to the center portion or edge of the
wafer from the process region of the reaction chamber. The first
and second driving shafts 292 and 294 are used to determine the
widths of the first and second gaps 70 and 80, respectively,
thereby freely adjusting the amount of reaction gas to be supplied
from the process region to the central portion or edge of the
wafer. Furthermore, this makes the amount of reaction gas supplied
even or uneven over the entire wafer surface depending on the type
of application.
[0099] FIGS. 16A-16C schematically illustrates a configuration of
main parts of a shower head according to a third embodiment of the
present invention. Referring to FIG. 16A, an elevating mechanism
392 and a rotating mechanism 394 are used as a gap controller for
determining the first and second gaps 70 and 80. Parts of the
shower head in this embodiment other than the elevating mechanism
392 and the rotating mechanism 394 have the same configuration as
described in the above embodiments. The elevating mechanism 392
drives the first baffle plate 30 upwardly or downwardly using a
first stepping motor 312 in order to determine the width of the
second gap 80. The rotating mechanism 394 drives the guide baffle
plate 50 upwardly or downwardly by means of a gear drive using the
second stepping motor 314.
[0100] The elevating mechanism 392 is integrated with the rotating
mechanism 394 as shown in FIG. 16A. The elevating mechanism 392 is
movable up or down by power transmitted from the first stepping
motor 312. The elevating mechanism 392 includes a shaft 382 that
extends to penetrate the guide baffle plate 50 and the first baffle
plate 30 and an outward flange 384 formed at one end of the shaft
382 for driving the first baffle plate 30 upwardly or downwardly to
follow the upward or downward movement of the shaft 382.
[0101] The rotating mechanism 394 includes the shaft 382 which is
rotatable by power transmitted from the second stepping motor 314,
and an external screw 372, formed at a position on an outer
circumference of the shaft 382 where the guide baffle plate 50 is
combined, for driving the guide baffle plate 50 upwardly or
downwardly according to the rotation of the shaft 382.
[0102] As shown in FIG. 16B, a central hole 350, through which the
shaft 382 passes, is formed at a central portion of the guide
baffle plate 50. An internal thread 352 mating with the external
thread of screw 372 is formed on an inner wall of the central hole
350.
[0103] As shown in FIG. 16C, at a central portion of the first
baffle plate 30, a central hole 332 penetrated by the shaft 382 is
in communication with a circular space 334 for housing the outward
flange 384 formed at the end of the shaft 382.
[0104] The width of the second gap 80 is adjusted using the
elevating mechanism 392. In this case, if the shaft 382 is moved up
or down by the elevating mechanism 392 in order to raise or lower
the first baffle plate 30, the guide baffle plate 50 is raised or
lowered to follow the upward or downward movement of the shaft 382
since the internal thread 352 engaging the external thread of screw
372 is formed in the guide baffle plate 50. Thus, the first baffle
plate 30 and the guide baffle plate 50 are simultaneously moved
upwardly or downwardly when the shaft 382 is moved up or down.
[0105] The width of the first gap 70 is adjusted using the rotating
mechanism 394. If the rotating mechanism 394 is used to rotate the
shaft 382, the guide baffle plate 50 is raised or lowered by
interaction of the external thread of screw 372 of the shaft 382
and the internal thread 352 formed in the central hole 350 of the
guide baffle plate 50. When the shaft 382 is rotated by the
rotating mechanism 394 in this way, the first baffle plate 30 does
not rotate but remains stationary since the circular space 334 for
housing the outward flange 384 is formed in the first baffle plate
30 so that rotation of the outward flange 384 does not affect the
first baffle plate 30. Here, in order to move the guide baffle
plate 50 upwardly or downwardly, instead of rotating it when the
shaft 382 is rotated by the rotating mechanism 394, a stopper 354
for preventing the rotation of the guide baffle plate 50 is
connected to the guide baffle plate 50.
[0106] In the above configuration, the elevating mechanism 392 and
the rotating mechanism 394 are used to determine the widths of the
second and first gaps 80 and 70, respectively, thereby adjusting
the amount of gas to be supplied from the process region to the
central portion or edge of the wafer as desired or making the
amount of reactant gas supplied even or uneven over the entire
wafer surface depending on the type of application.
[0107] FIG. 17 schematically illustrates a configuration of main
parts of a shower head according to a fourth embodiment of the
present invention. In FIG. 17, the same elements are denoted by the
same reference numerals, and a detailed explanation thereof will be
omitted.
[0108] In the embodiment shown in FIG. 17, a first baffle plate 430
is in contact with a second baffle plate 440. Thus, the width of
the second gap 80 disposed between the first and second baffle
plates 430 and 440 is effectively zero. A driving shaft 480 for
simultaneously driving the first and second baffle plates 430 and
440 upwardly or downwardly is disposed in order to determine the
width of the first gap 70 formed between the guide baffle plate 50
and the first baffle plate 430. When the second baffle plate 440 is
driven by the driving shaft 480 upwardly or downwardly, the first
baffle plate 430 is moved upwardly or downwardly to follow the
upward or downward movement of the second baffle plate 440, thereby
limiting the width of the first gap 70 by the bottom of the baffle
plate 50 and the top of the first baffle plate 430. The detailed
configuration of the guide baffle plate 50 is as described
above.
[0109] A rotating mechanism 490 is connected to the first baffle
plate 430. The first baffle plate 430 is rotatable with respect to
the second baffle plate 440 in a predetermined angular range by the
rotating mechanism 490. More specifically, the rotating mechanism
490 varies an angle of rotation of the first baffle plate 430 so
that the first and second baffle plates 430 and 440 contact each
other with various rotational angles.
[0110] FIG. 18 illustrates a top view of the first baffle plate
430. The first baffle plate 430 has a plurality of through holes
432. The plurality of through holes 432 are distributed to have
different opening ratios depending on a radius from a central axis
431 of the first baffle plate 430.
[0111] The first baffle plate 430 is divided into a plurality of
sectorial regions 435a, 435b, and 435c which extend radially from
the central axis 431 thereof. Each of the plurality of sectorial
regions 435a, 435b, and 435c has the plurality of through holes
432, which are formed only in a predetermined range, separated from
the central axis 431 by a selected radius. That is, the sectorial
region 435a has the plurality of through holes 432 formed only in a
first range 436a separated from the central axis 432 by a first
radius r.sub.1. The sectorial region 435b has the plurality of
through holes 432 formed only in a second range 436b separated from
the central axis 432 by a second radius r.sub.2 The sectorial
region 435c has the plurality of through holes 432 formed only in a
third range 436c separated from the central axis 432 by a third
radius r.sub.3.
[0112] FIG. 19 illustrates a top view of the second baffle plate
440. The second baffle plate 440 has a plurality of through holes
442. The plurality of through holes 442 are distributed to have
different opening ratios depending on the distance by which the
first baffle plate 430 rotates about a central axis 441 of the
second baffle plate 440.
[0113] The second baffle plate 440 is divided into a plurality of
sectorial regions 445a, 445b, and 445c that extend radially from
the central axis 441 thereof. Each of the plurality of sectorial
regions 445a, 445b, and 445c formed on the second baffle plate 440
has a size corresponding to each of the plurality of sectorial
regions 435a, 435b, and 435c formed on the first baffle plate 430.
The sectorial regions 445b and 445c have an opening ratio of zero
(i.e., no openings). The sectorial region 445a has a plurality of
through holes 442 arranged at regular intervals.
[0114] Since the first and second baffle plates 430 and 440 contact
each other as shown in FIG. 17, selected ones of the plurality of
through holes 432 formed on the first baffle plate 430 are in
communication with selected ones of the plurality of through holes
442 to thus form align holes. The opening position of the align
holes is changed depending on a distance by which the first baffle
plate 430 is rotated by the rotating mechanism 490.
[0115] FIGS. 20A-20C illustrate views from the bottom of the second
baffle plate 440 when the first and second baffle plates 430 and
440 contact each other with different rotational distances. That
is, FIGS. 20A-20C show changes in positions of the align holes
formed when the first baffle plate 430 contacts the second baffle
plate 440 while the first baffle plate 430 is rotated at various
angles by the rotating mechanism 490.
[0116] More specifically, FIG. 20A shows a state in which the first
baffle plate 430 has rotated by a predetermined angular distance by
the rotating mechanism 490 so that the sectorial region 435a of the
first baffle plate 430 and the sectorial region 445a of the second
baffle plate 440 overlap each other. In this case, only the
plurality of through holes 432 formed in the first range 436a among
the sectorial region 435a of the first baffle plate 430 communicate
with the plurality of through holes 442 formed in the sectorial
region 445a of the second baffle plate 440. As a result, align
holes 452 are formed only in the first range 436a, and the
remaining through holes 442 formed in the second baffle plate 440
are blocked by the first baffle plate 430. Thus, when the first
baffle plate 430 contacts the second baffle plate 440 as shown in
FIG. 20A, a greater amount of reaction gas is supplied from the
process region within the reaction chamber to an edge on the
wafer.
[0117] FIG. 20B illustrates a state in which the first baffle plate
430 has rotated by a predetermined angular distance by the rotating
mechanism 490 so that the sectorial region 435b of the first baffle
plate 430 and the sectorial region 445a of the second baffle plate
440 overlap each other. In this case, only the plurality of through
holes 442 formed in the second range 436b among the sectorial
region 435a of the first baffle plate 430 communicate with the
plurality of through holes 442 formed in the sectorial region 445a
of the second baffle plate 440. As a result, the align holes 452
are formed only in the second range 436b, and the remaining through
holes 442 formed in the second baffle plate 440 are blocked by the
first baffle plate 430. Thus, when the first baffle 430 contacts
the second baffle plate 440 as shown in FIG. 20B, a greater amount
of reaction gas is supplied from the process region within the
reaction chamber to an intermediate region between a central region
and an edge on the wafer.
[0118] FIG. 20C illustrates a state in which the first baffle plate
430 has rotated by a predetermined angular distance by the rotating
mechanism 490 so that the sectorial region 435c of the first baffle
plate 430 and the sectorial region 445a of the second baffle plate
440 overlap each other. In this case, only the plurality of through
holes 432 formed in the third range 436c among the sectorial region
435c of the first baffle plate 430 communicate with the plurality
of through holes 442 formed in the sectorial region 445a of the
second baffle plate 440. As a result, the align holes 452 are
formed only in the third range 436c, and the remaining through
holes 442 formed in the second baffle plate 440 are blocked by the
first baffle plate 430. Thus, when the first baffle 430 contacts
the second baffle plate 440 as shown in FIG. 20C, a greater amount
of reaction gas is supplied from the process region to a region
near a central portion on the wafer within the reaction
chamber.
[0119] As described above, the opening position of the align holes
452 formed by overlapping the first and second baffle plates 430
and 440 varies with the rotational distance of the first baffle
plate which is varied by the rotating mechanism 490. Thus, in order
to adjust the amount of reactant gas supplied to a particular
position on the wafer within the process region, the rotating
mechanism 490 is used to control the rotational angle of the first
baffle plate 430 and thus select the opening position of the align
holes 452.
[0120] FIG. 21 illustrates a cross-sectional view for explaining
the configuration of main parts of a shower head according to a
fifth embodiment of the present invention. In FIG. 21, the same
elements are denoted by the same reference numerals, and a detailed
explanation thereof will be omitted.
[0121] Similar to the first embodiment shown in FIG. 1, the shower
head according to the fifth embodiment shown in FIG. 21 includes a
first baffle plate 530 disposed between the top plate 10 and the
face plate 20 and a second baffle plate 540 disposed between the
first baffle plate 530 and the face plate 20. The second baffle
plate 540 has a top surface that limits the second gap 80 for
forming a flow passage of the reactant gas between the first and
second baffle plates 530 and 540. In order to control the amount of
the reactant gas through the second gap 80 formed between the first
and second baffle plates 530 and 540, a plurality of piezoelectric
elements 582, 584, and 586 are disposed on the top surface of the
second baffle plate 540.
[0122] FIG. 22 illustrates a top view of the first baffle plate
530. As shown in FIG. 22, the first baffle plate 530 has a
plurality of first, second and third through holes 532, 534, and
536. The plurality of first through holes 532 are formed at a
position separated from a central axis 531 of the first baffle
plate 530 by a first radius R.sub.1. The plurality of second
through holes 534 are formed at a position separated from the
central axis 531 thereof by a second radius R.sub.2, which is
greater than the first radius R.sub.1. The plurality of third
through holes 536 are formed at a position separated from the
central axis 531 by a third radius R.sub.3, which is greater than
the second radius R.sub.2.
[0123] FIG. 23 is a top view of the second baffle plate 540. As
shown in FIG. 23, the second baffle plate 540 has a fourth through
hole 542 and a plurality of fifth, sixth, and seventh through holes
544, 546, and 548, respectively. The fourth through hole 542 is
formed at a position of a central axis 541 of the second baffle
plate 540. The plurality of fifth through holes 544 are formed at a
position separated from the central axis 541 by a fourth radius
R.sub.4. The plurality of sixth through holes 546 are formed at a
position separated from the central axis 541 by a fifth radius
R.sub.5, which is greater than the fourth radius R.sub.4. The
plurality of seventh through holes 548 are formed at a position
separated from the central axis 541 by a sixth radius R.sub.6,
which is greater than the fifth radius R.sub.5.
[0124] The plurality of piezoelectric elements 582, 584, 586
includes a first annular piezoelectric element 582 disposed between
the fourth and fifth through holes 542 and 544 on the second baffle
plate 540, a second piezoelectric element 584 disposed between the
fifth and sixth through holes 544 and 546 on the second baffle
plate 540, and a third piezoelectric element 586 disposed between
the sixth and seventh through holes 546 and 548 on the second
baffle plate 540. The first through third piezoelectric elements
582, 584, and 586 are bonded to the second baffle plate 540. The
position at which the first piezoelectric element 582 is located on
the second baffle plate 540 corresponds to the position at which
the plurality of first through holes 532 of the first baffle plate
530 are formed. The position at which the second piezoelectric
element 584 is located on the second baffle plate 540 corresponds
to the position at which the plurality of second through holes 534
of the first baffle plate 530 are formed. The position at which the
third piezoelectric element 586 is located on the second baffle
plate 540 corresponds to the position at which the plurality of
third through holes 536 of the first baffle plate 530 are
formed.
[0125] FIG. 24 illustrates an enlarged view of a portion "A" of
FIG. 21. Referring to FIGS. 21-24, each of the plurality of
piezoelectric elements 582, 584, and 586 includes a piezoelectric
layer 572 vibrating in a thickness extensional mode according to an
application of a voltage. The piezoelectric element 572 may be
formed of lead zirconate titanate (PZT), PbTiO.sub.3, BaTiO.sub.3,
or poly vinylidene fluoride (PVDF) polymer. The piezoelectric layer
572 has two main faces at either side thereof on which first and
second electrodes 574 and 576 are formed, respectively. An
insulating layer 578 is formed on the first electrode 574 adjacent
to the first baffle plate 530. The second electrode 576 is
constructed by the second baffle plate 540. That is, the second
baffle plate 540 additionally serves as the second electrode 576.
Thus, the piezoelectric element 582 includes a bonding surface
between the piezoelectric layer 572 and the second baffle plate
540. In this case, the second baffle plate 540 is preferably formed
of aluminum.
[0126] A voltage is applied to the piezoelectric elements 582, 584,
and 586 from a power supply unit 590. The thickness expansion rate
of the piezoelectric layer 572 of each of the piezoelectric
elements 582, 584, and 586 may be controlled by the level of
voltage applied from the power supply unit 590. The thickness
expansion rate of the piezoelectric layer 572 adjusts the distance
between the first piezoelectric element 582 and the first through
hole 532 and consequently the amount of a reactant gas 510 flowing
from the first through hole 532 of the first baffle plate 530 into
the second gap 80. Since the thickness expansion rate of the
piezoelectric layer 572 is controlled by adjusting the level of a
voltage supplied from the power supply unit 590, the supplied
voltage selectively opens or closes the first through holes 532 of
the first baffle plate 530. The above configuration of the first
piezoelectric element 582 is similarly applied to the second and
third piezoelectric elements 584 and 586. Adopting the
configuration cannot only selectively open or close through holes,
which are spaced apart from the central axis 531 of the first
baffle plate 530 by a desired radius among the first through third
though holes 532, 534, and 536 formed in the first baffle plate
530, but can also adjust the amount of reactant gas flowing through
the through holes. Thus, the piezoelectric elements 582, 584, and
586, each of which has a thickness expansion rate varying depending
on the level of an applied voltage, are used to selectively control
the amount of the reactant gas flowing through the plurality of
first through third through holes 532, 534, and 536 formed in the
first baffle plate 530 according to the amount of reactant gas
required on a specific position on the wafer within the process
region of the reaction chamber.
[0127] Although not shown, the shower head having the configuration
as described above with reference to FIG. 21 may further include
the guide baffle plate 50 disposed on the first baffle plate 530 as
described above with reference to FIGS. 5A-5C. In this case, a gap
corresponding to the first gap 70 is formed between the guide
baffle plate 50 and the first baffle plate 530, thereby providing a
lateral flow passage of the reactant gas.
[0128] The shower head may further include the third baffle plate
60 disposed between the second baffle plate 540 and the face plate
20 as described above with reference to FIG. 7.
[0129] As described with reference to FIGS. 21-24, if the
piezoelectric elements 582, 584, and 586 are used to adjust the
amount of reactant gas between the first and second baffle plates
530 and 540, the amount of the reactant gas supplied is adjusted in
a radial direction from the center of the shower head according to
the level of a voltage applied from the power supply unit 590.
Accordingly, no mechanical movement is required in the shower head
while improving control performance for adjusting the amount of
reaction gas supplied.
[0130] As described above, a shower head according to the present
invention includes a gap controller for determining the width of a
gap for forming a flow passage of reactant gas between adjacent two
baffle plates. The width of the gap is selectively decreased or
increased by the gap controller, thereby adjusting the amount of
reactant gas supplied to a particular position on a wafer in a
process region of a reaction chamber and making the amount of the
reactant gas supplied to a position on the wafer even or uneven
depending on the type of application.
[0131] Thus, according to the present invention, it is easier to
adjust the distribution of the reactant gas depending on a position
on the wafer in order to obtain optimized etch rate uniformity over
the entire wafer surface during the fabrication process of a
semiconductor device. Moreover, the present invention makes it
possible to freely adjust the amount of reactant gas supplied,
thereby compensating in advance for degradation in etch rate
uniformity that may partially occur on the wafer during an etch
step and consequently optimizing the etch rate uniformity. Thus,
the present invention not only freely optimizes pattern uniformity
depending on a position on the wafer but also does not need to
significantly consider uniformity over the entire wafer surface,
thereby reducing the time and costs in developing a semiconductor
device manufacturing apparatus.
[0132] Preferred embodiments of the present invention have been
disclosed herein, and, although specific terms are employed, they
are used and are to be interpreted in a generic and descriptive
sense only and not for purpose of limitation. Accordingly, it will
be understood by those of ordinary skill in the art that various
changes in form and details may be made without departing from the
spirit and scope of the present invention as set forth in the
following claims.
* * * * *