U.S. patent application number 09/191203 was filed with the patent office on 2001-12-13 for gas delivering device.
Invention is credited to TAI, WEN-FA, TU, AN-CHUN.
Application Number | 20010050051 09/191203 |
Document ID | / |
Family ID | 21631164 |
Filed Date | 2001-12-13 |
United States Patent
Application |
20010050051 |
Kind Code |
A1 |
TU, AN-CHUN ; et
al. |
December 13, 2001 |
GAS DELIVERING DEVICE
Abstract
A gas delivering device inside a gaseous reaction chamber
capable of increasing gas flow in areas having a deficient supply
of gas by forming additional air holes in corresponding positions.
Because a gas-delivering panel design having asymmetrical air holes
is employed, gas flow rate within the reaction chamber can be
roughly balanced. Hence, a homogeneous stream of gaseous reactants
can be maintained above the surface of a reacting wafer.
Inventors: |
TU, AN-CHUN; (TAIPEI CITY,
TW) ; TAI, WEN-FA; (HSINCHU CITY, TW) |
Correspondence
Address: |
BLAKELY SOKOLOFF TAYLOR & ZAFMAN
12400 WILSHIRE BOULEVARD
7TH FLOOR
LOS ANGELES
CA
900251026
|
Family ID: |
21631164 |
Appl. No.: |
09/191203 |
Filed: |
November 12, 1998 |
Current U.S.
Class: |
118/715 ;
156/345.33 |
Current CPC
Class: |
H01J 37/32449 20130101;
H01J 37/3244 20130101; C23C 16/45565 20130101; C23C 16/455
20130101 |
Class at
Publication: |
118/715 ;
156/345 |
International
Class: |
C23C 016/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 27, 1998 |
TW |
87114165 |
Claims
What is claimed is:
1. A gas delivering device installed inside a reaction chamber,
comprising a gas-delivering panel having asymmetrically placed air
holes whose positions are determined by environmental factors
within the reaction chamber.
2. The structure of claim 1, wherein the environmental factors
includes gas flow rate in various places within the reaction
chamber.
3. The structure of claim 1, wherein the environmental factors
include distribution of pressure within the reaction chamber.
4. The structure of claim 1, wherein the gas delivering panel has a
circular shape.
5. A gas delivering structure installed inside a reaction chamber,
comprising a gas delivering panel having a group of symmetrically
positioned air holes and a group of air holes at one corner sector
of the symmetrically positioned air holes for adjusting gas flow
rate.
6. The structure of claim 5, wherein the group of air holes for
adjusting gas flow rate are positioned above areas within the
chamber where the gas flow rate is slow.
7. The structure of claim 5, wherein the group of air holes for
adjusting gas flow are positioned above areas within the chamber
where gas pressure is low.
8. The structure of claim 5, wherein the gas delivering panel has a
circular shape.
9. The structure of claim 5, wherein the group of symmetrically
positioned air holes is on the perimeter of a circle.
10. The structure of claim 5, wherein the group of symmetrically
positioned air holes is on the perimeter of a symmetrical polygon.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Taiwan
application serial no. 87114165, filed Aug. 27, 1998, the full
disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] The present invention relates to a gas-delivering device
installed within a semiconductor reaction chamber. More
particularly, the present invention relates to a gas-delivering
device that can be used for balancing gas flow rate inside the
reaction chamber according to the conditions within the
chamber.
[0004] 2. Description of Related Art
[0005] As IC fabrication is now in the sub-micron range and
processing diameter of a silicon wafer continues to increase, how
to establish a highly uniform plasma atmosphere in a reaction
chamber is of growing importance. Ultimate uniformity of a
processed wafer and microloading effect are closely related to the
uniformity of plasma within a reaction chamber. The so-called
microloading effect refers to the difference in etching rate or
depositing rate in an etching operation or thin film production
that results from a variation of exposed area due to a specific
pattern distribution. Consequently, in semiconductor manufacturing
operations such as etching or layer deposition, a system capable of
providing a uniform supply of gases source is very important.
[0006] FIG. 1 is a cross-sectional view showing the layout of a
conventional reaction chamber. As shown in FIG. 1, a gas-delivering
panel 110 and a negative electrode are located inside a reaction
chamber 100. The gas-delivering panel 110 can be fixed to the
ceiling of the reaction chamber 100, while a wafer 120 can be
placed on top of the negative electrode. The reaction chamber 100
has an exhaust outlet connected to a pump via a throttle valve.
When the pump is in operation, gases within the chamber 100 are
sucked out to maintain a high degree of vacuum within the reaction
chamber 100. Furthermore, when a thin film deposition or an etching
operation is performed, gaseous reactants can flow into the
reaction chamber 100 through the gas-delivering panel 110 so that
appropriate reactions with the wafer 120 can take place within the
chamber. Structural details of the gas-delivering panel can be seen
in FIGS. 2A and 2B.
[0007] FIGS. 2A and 2B are the top views of two types of
conventional gas-delivering panel installed on the ceiling of the
reaction chamber as shown in FIG. 1. As shown in FIGS. 2A and 2B,
the gas-delivering panels 110 have a circular plate-like structure
with a plurality of symmetrically positioned air holes 112. Here,
the symmetry point is the center of the circular plate-like
structure. Because the gas-delivering panel 110 is installed on the
ceiling of the reaction chamber 100, gases coming down from the air
holes 112 are able to react with the wafer 120 (FIG. 1) in etching
or film growing operations.
[0008] Since the gas-delivering panel 110 is fixed in position on
the ceiling of the reaction chamber 100, gases diffusing down
through the symmetrical air holes 112 ought to be able to form a
uniform layer of gas above the wafer. However, in reality, gas flow
within the chamber is highly asymmetrical due to the asymmetrical
nature of the fixtures within the reaction chamber 100. Therefore,
non-uniformity of gas flow or even a turbulent gas flow is the
norm, especially when the pump is operating to create a vacuum.
Under such circumstances, uniformity of wafer deposition or etching
is affected and microloading effect intensifies. Consequently,
product yield is lower and die quality deteriorates.
[0009] In light of the foregoing, there is a need to provide a
gas-delivering panel structure capable of smoothing the flow of
gaseous reactants within the reaction chamber.
SUMMARY OF THE INVENTION
[0010] Accordingly, the present invention is to provide a
gas-delivering device capable of balancing the gas flow rate
directed towards a wafer surface according to the actual conditions
within the chamber. Hence, a uniform flow of gaseous reactants is
delivered to a wafer surface for carrying out various types of
reactions.
[0011] To achieve these and other advantages and in accordance with
the purpose of the invention, as embodied and broadly described
herein, the invention provides a gas-delivering device for a
reaction chamber. The gas-delivering device comprises a panel that
includes air holes drilled in it such that a greater number of air
holes is formed in places where gas flow is weak. Since the air
holes are distributed asymmetrically around the gas-delivering
panel, more gases can be diverted to chamber areas where the gas
flow rate is deficient. Therefore, gaseous reactants can be more
uniformly spread inside the reaction chamber.
[0012] Actual position of the asymmetrically placed air holes
depends very much on the actual gas flow conditions within the
reaction chamber. In general, asymmetrical air hole patterns are
formed near places where the gas flow rate is small or air pressure
is low. Consequently, a larger volume of gas can flow into these
gas deficient areas, thereby homogenizing the gaseous distribution
inside the chamber.
[0013] It is to be understood that both the foregoing general
description and the following detailed description are exemplary,
and are intended to provide further explanation of the invention as
claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the invention and, together with the description,
serve to explain the principles of the invention. In the
drawings,
[0015] FIG. 1 is a cross-sectional view showing the layout of a
conventional reaction chamber;
[0016] FIGS. 2A and 2B are the top views of two types of
conventional gas-delivering panel installed on the ceiling of the
reaction chamber as shown in FIG. 1; and
[0017] FIGS. 3A and 3B are top views showing the distribution of
air holes of two types of gas-delivering panel according to this
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] Reference will now be made in detail to the present
preferred embodiments of the invention, examples of which are
illustrated in the accompanying drawings. Wherever possible, the
same reference numbers are used in the drawings and the description
to refer to the same or like parts.
[0019] This invention provides a gas-delivering device capable of
adjusting the gas flow rate into a reaction chamber according to
the actual gas flow conditions inside the reaction chamber.
Consequently, a uniform flow of gas is delivered to the reacting
surface of the wafer, and a high-quality wafer operation can be
conducted.
[0020] Principally, the invention relies on forming a greater
number of air holes in areas where flow of gas inside a reaction
chamber is weak. Because the gas-delivering panel has an
asymmetrical distribution of air holes, areas where gas flow is
deficient can be compensated for by forming more air holes.
Normally, gas flow is deficient in places such as the outlet port
of the pump or its adjacent sides. Therefore, layout of the air
holes depends very much on the actual chamber design. Moreover, the
layout of air holes may be dependent upon the properties of gaseous
plasma used in a particular reaction.
[0021] FIGS. 3A and 3B are top views showing the distribution of
air holes of two types of gas-delivering panel according to this
invention.
[0022] First, as shown in FIG. 3A, besides the symmetrically
distributed air holes 202A around the center of the gas-delivering
panel 200A, an arc of air holes 204A is formed at one corner
sector. Hence, an asymmetrical distribution of air holes is
created. The air holes 204A are positioned according to the actual
flow of gas within the reaction chamber. For example, the air holes
are placed near areas where the gas flow rate is slow or gas
pressure is low. Consequently, those "weak" areas can be
compensated for by the extra gas flow from the extra air holes
204A, and hence a more homogeneous distribution of gas is
achieved.
[0023] In another embodiment as shown in FIG. 3B, besides the
symmetrically distributed hexagonal pattern of air holes 202B
around the center of the gas-delivering panel 200B, a bank of air
holes 204B is formed not far from one side of the polygon. Hence,
an asymmetrical distribution of air holes is created. The air holes
204B are positioned according to the actual flow of gas within the
reaction chamber. For example, the air holes are placed near areas
where the gas flow rate is slow or gas pressure is low.
Consequently, those "weak" areas can be compensated for by the
extra gas flow from the extra air holes 204B, and hence a more
homogeneous distribution of gas is achieved.
[0024] In summary, the asymmetrically-placed air holes on the
gas-delivering panel as shown in FIGS. 3A and 3B are formed in
positions where the gas flow rate is deficient. Through careful
adjustment of the number and position of those air holes, a
homogeneous gas flow is obtained. Therefore, wafer reaction within
the chamber can be carried out in a uniform environment.
[0025] Obviously, asymmetrical distribution of air holes should not
be restricted to the configuration shown in FIG. 3A or FIG. 3B. In
practice, the asymmetrical air holes can be placed anywhere
according to the design of a particular reaction chamber or the
particular properties of gaseous plasma.
[0026] Hence, the advantages of using asymmetrical air holes
compared with the conventional symmetrical air holes includes:
[0027] 1. The asymmetrical air holes can rectify any odd type of
reaction chamber design immediately and boost the efficiency of the
hardware. Therefore, IC processing becomes more stable.
[0028] 2. The asymmetrical air holes can compensate for any
intrinsic asymmetrical gas flow within the chamber due to any
structural asymmetry. Therefore, difference in processing
parameters between different reaction chambers can be greatly
reduced.
[0029] 3. Homogeneity of wafer reaction can be increased
considerably.
[0030] 4. Asymmetrical air hole design can save developing time and
cost compared with a conventional gas-delivering panel having
symmetrical air holes.
[0031] 5. The invention is able to reduce developing time for new
processing operations.
[0032] 6. A more homogeneous stream of gaseous reactants is
produced for carrying out wafer reaction. Hence, existing limits in
wafer processing operations can be relaxed and the efficiency of
wafer reaction station is thus improved.
[0033] Although a circular type of gas-delivering panel is used
throughout the aforementioned illustration, the panel is by no
means restricted to such a geometric shape. Anybody familiar with
the technologies should be able to provide panels having other
geometric shapes that can perform the same function equally within
the scope of this invention.
[0034] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure of the
present invention without departing from the scope or spirit of the
invention. In view of the foregoing, it is intended that the
present invention cover modifications and variations of this
invention provided they fall within the scope of the following
claims and their equivalents.
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