U.S. patent application number 10/054414 was filed with the patent office on 2003-01-30 for chuck assembly of etching apparatus for preventing byproducts.
This patent application is currently assigned to Samsung Electronics Co., Ltd.. Invention is credited to Choi, Chang-Won, Kim, Jaung-Joo, Kim, Tae-Ryong.
Application Number | 20030019584 10/054414 |
Document ID | / |
Family ID | 19712525 |
Filed Date | 2003-01-30 |
United States Patent
Application |
20030019584 |
Kind Code |
A1 |
Choi, Chang-Won ; et
al. |
January 30, 2003 |
Chuck assembly of etching apparatus for preventing byproducts
Abstract
A chuck assembly of an etching apparatus capable of improving an
etching rate at an edge portion of a wafer, thereby preventing
byproducts from being formed along the edge portion of the wafer is
disclosed. The chuck assembly comprises a chuck body comprising a
stepped portion at an edge side portion of the chuck body for
supporting a central portion of a wafer; an edge ring, received in
the stepped portion of the chuck body, for supporting an edge
portion of the wafer, wherein the edge ring has less resistance
than the resistance of the wafer; and an insulating ring provided
at a surrounding portion of the chuck body, for supporting a bottom
portion of the edge ring, the bottom portion of the edge ring being
extended toward outside of the chuck body.
Inventors: |
Choi, Chang-Won; (Seoul,
KR) ; Kim, Tae-Ryong; (Suwon-city, KR) ; Kim,
Jaung-Joo; (Suwon-city, KR) |
Correspondence
Address: |
F. Chau & Associates, LLP
Suite 501
1900 Hempstead Turnpike
East Meadow
NY
11554
US
|
Assignee: |
Samsung Electronics Co.,
Ltd.
|
Family ID: |
19712525 |
Appl. No.: |
10/054414 |
Filed: |
January 22, 2002 |
Current U.S.
Class: |
156/345.51 |
Current CPC
Class: |
H01L 21/67069 20130101;
H01J 37/32431 20130101 |
Class at
Publication: |
156/345.51 |
International
Class: |
C23F 001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 25, 2001 |
KR |
2001-44892 |
Claims
What is claimed is:
1. A chuck assembly of an etching apparatus, the chuck assembly
comprising: a chuck body comprising a stepped portion at an edge
side portion of the chuck body, for supporting a central portion of
a wafer; an edge ring, received in the stepped portion of the chuck
body, for supporting an edge portion of the wafer, wherein the edge
ring has less resistance than the resistance of the wafer; and an
insulating ring provided at a surrounding portion of the chuck
body, for supporting a bottom portion of the edge ring, the bottom
portion of the edge ring being extended toward outside of the chuck
body.
2. The chuck assembly of claim 1, wherein the difference in the
resistance between the edge ring and the wafer is about 0.005 to
about 4.5 .OMEGA..
3. The chuck assembly of claim 1, wherein the resistance of the
edge ring is about 3.5 to about 1.5 .OMEGA..
4. The chuck assembly of claim 1, wherein the edge ring comprises a
slanted step portion whose surface forms an angle of about 40 to
about 80 degrees relative to a normal to the wafer surface.
5. The chuck assembly of claim 4, wherein the slanted step portion
of the edge ring begins from about 1.5 to about 4.5 mm from the
edge portion of the wafer.
6. The chuck assembly of claim 4, wherein the slanted step portion
of the edge ring begins from about 1.5 to about 2.5 mm from the
edge portion of the wafer.
7. A chuck assembly for a semiconductor etching apparatus, the
chuck assembly comprises: a chuck body for supporting a
semiconductor wafer; an edge ring, disposed on the chuck body, for
supporting an edge portion of the wafer; an insulating ring,
disposed on the outside portion of the chuck body, for supporting
the edge ring; wherein the electrical resistance of the edge ring
is less than the electrical resistance of the wafer so as to
uniformly etch the portion of the wafer supported by the edge ring
during an etch process.
8. The chuck assembly of claim 7, wherein the difference in the
electrical resistance between the edge ring and the wafer is about
0.005 to about 4.5 .OMEGA..
9. The chuck assembly of claim 7, wherein the electrical resistance
of the edge ring is about 3.5 to about 1.5 .OMEGA..
10. The chuck assembly of claim 7, wherein the edge ring comprises
a slanted step portion whose surface forms an angle of about 40 to
about 80 degrees relative to a normal to the wafer surface.
11. The chuck assembly of claim 10, wherein the slanted step
portion of the edge ring begins from about 1.5 to about 4.5 mm from
the edge portion of the wafer.
12. The chuck assembly of claim 10, wherein the slanted step
portion of the edge ring begins from about 1.5 to about 2.5 mm from
the edge portion of the wafer.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based on Korean Patent Application No.
2001-44892 filed on Jul. 25, 2001.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention relates to an etching apparatus of a
semiconductor device, and more particularly, to an etching
apparatus comprising a chuck assembly for preventing byproducts
being formed along an edge portion of a wafer, thereby improving a
production yield of a semiconductor device.
[0004] 2. Description of Related Art
[0005] Generally, an etching process of semiconductor devices, for
example, a plasma etching process, is performed to etch a certain
portion of a wafer exposed by a photo-resist patterning process.
Typically, a plasma etching process comprises supplying a process
gas on a wafer positioned between upper and lower electrodes, and
then applying high frequency power to charge the process gas to a
plasma state. The plasma then reacts with the portion of the wafer
exposed during a photo-resist patterning process. It is required
that the plasma-state gas uniformly reacts with the entire surface
of the wafer.
[0006] FIG. 1 is a sectional view of a chuck assembly of a
conventional etching apparatus, and FIG. 2 is an enlarged sectional
view of the portion II in FIG. 1. Referring to FIG. 1, a chuck
assembly comprises a main body 12 for supporting a central portion
of a wafer W except an edge portion of the wafer W. An edge ring 14
is provided on an edge portion of the chuck main body 12. The edge
ring 14 comprises a stepped portion and is made of similar silicon
material as the wafer W. High frequency power is applied to an
upper electrode 10 of the wafer W.
[0007] An inner side portion of the edge ring 14, as shown in FIGS.
1 and 2, comprises a step shape having a predetermined thickness
for supporting the edge portion of the wafer W exposed by the step
edge portion of the chuck main body 12. The bottom portion of the
edge ring 14 is extended to the edge portion of the chuck body 12
and is supported by an insulating ring 16 fixed to a side wall of
the chuck body 12.
[0008] When an etching process is performed with the conventional
chuck assembly, the edge ring 14 serves to distribute a plasma gas
up to the edge portion of the wafer W in response to the
high-frequency power applied to the upper electrode 10 of the wafer
W. Thus, the plasma gas affects the entire surface of the wafer W.
However, a slanted portion B at the edge side portion of the wafer
W cannot be sufficiently etched to a desired thickness during the
etching process. As a result, residual byproducts of a cone shape
remain at the slanted portion B of the wafer W. As shown in FIG. 3,
these cone shaped residuals form a flow shaped pattern at a flat
portion F on an inferior wafer along the edge portion of the wafer
W during a following process, thereby decreasing a production yield
and productivity thereof.
SUMMARY OF THE INVENTION
[0009] To solve the problem, it is an object of the present
invention to provide an etching apparatus comprising a chuck
assembly capable of improving an etching rate at an edge portion of
a wafer, thereby preventing byproducts from being formed along the
edge portion of the wafer.
[0010] According to an aspect of the present invention, a chuck
assembly of an etching apparatus is provided. The chuck assembly
comprises a chuck body comprising a stepped portion at an edge side
portion of the chuck body, for supporting a central portion of a
wafer; an edge ring, received in the stepped portion of the chuck
body, for supporting an edge portion of the wafer, wherein the edge
ring has less resistance than the resistance of the wafer; and an
insulating ring provided at a surrounding portion of the chuck
body, for supporting a bottom portion of the edge ring, the bottom
portion of the edge ring being extended toward outside of the chuck
body.
[0011] The difference in the resistance between the edge ring and
the wafer is preferably about 0.005 to about 4.5 .OMEGA.. For
example, the resistance of the edge ring is about 3.5 to about 1.5
.OMEGA.. The edge ring preferably comprises a slanted step portion
whose surface forms an angle of about 40 to about 80 degrees
relative to a normal to the wafer surface. The slanted step portion
of the edge ring begins from about 1.5 to about 4.5 mm, more
preferably, about 1.5 to about 2.5 mm from the edge portion of the
wafer.
[0012] According to another aspect of the present invention, a
chuck assembly for a semiconductor etching apparatus is provided.
The chuck assembly comprises a chuck body for supporting a
semiconductor wafer; an edge ring, disposed on the chuck body, for
supporting an edge portion of the wafer; an insulating ring,
disposed on the outside portion of the chuck body, for supporting
the edge ring; wherein the electrical resistance of the edge ring
is less than the electrical resistance of the wafer so as to
uniformly etch the portion of the wafer supported by the edge ring
during an etch process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The foregoing and other objects, aspects and advantages will
be better understood from the following detailed description of
preferred embodiments of the invention with reference to the
drawings, in which;
[0014] FIG. 1 is a sectional view showing a chuck assembly of a
conventional etching apparatus;
[0015] FIG. 2 is an enlarged sectional view of the portion II of
the chuck assembly of FIG. 1;
[0016] FIG. 3 is a plane view illustrating cone shaped residuals
remained on a wafer in using the chuck assembly of FIG. 1 to etch
the wafer; and
[0017] FIG. 4 is a partial sectional view illustrating a chuck
assembly of an etching apparatus according to an embodiment of the
present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0018] Herein after, the present invention will be described in
detail with reference to the accompanying drawings. It should be
noted that similar reference numerals are used in the accompanying
drawings to designate similar or equivalent parts or portions.
Further, although exemplary specifications will be provided in the
following discussion to provide a thorough understanding of the
present invention, it is to be understood by those one skilled in
the art that the present invention can be achieved without such
specifications. A detailed description of well-known functions and
structures will be omitted so as to clarify key points of the
present invention.
[0019] FIG. 4 is a partial sectional view illustrating a chuck
assembly of an etching apparatus according to an embodiment of the
present invention. Advantageously, a chuck assembly according to an
embodiment of the present invention improves an accuracy of etching
at an edge portion of a wafer and enables high frequency to be
uniformly distributed over the wafer.
[0020] As shown in FIG. 4, a chuck assembly according to an
embodiment of the present invention comprises a chuck body 12 for
supporting a center portion of a wafer W (except an edge portion of
the wafer W). An edge ring 20, which is formed in a stepped portion
in the edge portion of the chuck body 12, supports an edge portion
of the wafer W. An insulating ring (see, 16 in FIG. 1) is provided
at a surrounding portion of the chuck body 12 for supporting a
bottom portion of the edge ring 20 extended toward outside of the
chuck body 12. The edge ring 20 is supported by the stepped portion
of the chuck body 12 and the edge ring 20 comprises a stepped
portion at an inner side portion thereof.
[0021] Preferably, the edge ring 20 has less electrical resistance
than the electrical resistance of the wafer W such that the
difference in the resistance between the edge ring 20 and the wafer
W is less than about 0.005 to about 4.5 .OMEGA.. For instance, if
the edge ring 20 has resistance of about 1.5 to about 3.5 .OMEGA.,
the wafer W preferably has resistance of about 5 106 .
[0022] Advantageously, since the edge ring 20 has less resistance
than the resistance of the wafer W, high frequency power is evenly
activated at the edge portion of the wafer W (that is placed on the
edge ring 20 and the stepped portion of the chuck body 12), thereby
effectively etching a slant portion (see, B in FIG. 2) at the edge
portion of the wafer W and preventing cone shaped residuals from
remaining along the edge portion of the wafer W.
[0023] Referring back to FIG. 2, surface "A" between an upper
portion P' and lower portion P of the inner side portion of the
edge ring 14 is slanted at an angle (.quadrature.) of about 15
degrees with respect to a vertical line (which, as shown, is a
normal to surface of the wafer). In other words, because the upper
portion P' has an acute angle to the normal, i.e., keen-edged, the
upper portion P' serves to concentrate the plasma effect of high
frequency power on undesired portions, thereby decreasing the etch
rate at the edge portion of the wafer W.
[0024] In contrast, the structure of the edge ring 20 according to
an embodiment of the present invention, as shown in FIG. 4,
comprises a surface "a" between an upper portion p' and a lower
portion p at an inner stepped portion of the edge ring 20. The
surface "a" is gently slanted with a normal in an angle
(.quadrature.') of about 40 to about 80 degrees, relative to a
normal to the wafer surface.
[0025] Further, the lower portion p of the edge ring 20 according
to an embodiment of the present invention has a longer distance 1
from the edge portion of the wafer W than a distance L of the lower
portion P of the edge ring 14 as shown in FIG. 2. The distance 1
may have a range of about 1.5 to about 4.5 mm, more preferably a
range of about 1.5 to about 2.5 mm.
[0026] With a chuck assembly of an etching apparatus according to
an embodiment of the present invention, high frequency power that
is applied to a wafer during an etching process effectively and
uniformly distributes a plasma gas over a wafer such that an
exposed portion of the wafer is accurately and evenly etched by the
plasma gas, thereby preventing the formation of cone-shaped
residuals along an edge portion of the wafer.
[0027] While the invention has been described in terms of preferred
embodiments, those skilled in the art will recognize that the
invention can be practiced with modification within the sprit and
scope of the appended claims.
* * * * *