U.S. patent application number 12/854371 was filed with the patent office on 2011-02-24 for plasma etching device.
Invention is credited to Hwankook CHAE, Yunkwang CHOI, Dongseok LEE, Heeseok MOON.
Application Number | 20110042009 12/854371 |
Document ID | / |
Family ID | 43604347 |
Filed Date | 2011-02-24 |
United States Patent
Application |
20110042009 |
Kind Code |
A1 |
LEE; Dongseok ; et
al. |
February 24, 2011 |
PLASMA ETCHING DEVICE
Abstract
A plasma etching device is provided. The device includes a
chamber, a cathode assembly, and an integral cathode liner. The
chamber provides a plasma reaction space. The cathode assembly is
positioned at an inner and central part of the chamber and supports
a substrate. The integral cathode liner has a plurality of first
vents and second vents formed at two levels and spaced apart
respectively such that the uniformity of a gas flow and exhaust
flow within the chamber is maintained, and is outer inserted to the
cathode assembly and coupled at its lower end part to an inner
surface of the chamber.
Inventors: |
LEE; Dongseok; (Suwon-city,
KR) ; CHAE; Hwankook; (Suwon-city, KR) ; MOON;
Heeseok; (Suwon-city, KR) ; CHOI; Yunkwang;
(Suwon-city, KR) |
Correspondence
Address: |
IPLA P.A.
3550 WILSHIRE BLVD., 17TH FLOOR
LOS ANGELES
CA
90010
US
|
Family ID: |
43604347 |
Appl. No.: |
12/854371 |
Filed: |
August 11, 2010 |
Current U.S.
Class: |
156/345.43 |
Current CPC
Class: |
H01J 37/32449 20130101;
H01J 37/3244 20130101; H01J 37/32834 20130101; H01J 37/32633
20130101; H01J 37/32623 20130101 |
Class at
Publication: |
156/345.43 |
International
Class: |
C23F 1/08 20060101
C23F001/08 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 18, 2009 |
KR |
10-2009-0076043 |
Claims
1. A plasma etching device comprising: a chamber for providing a
plasma reaction space; a cathode assembly positioned at an inner
and central part of the chamber and supporting a substrate; and an
integral cathode liner having a plurality of first vents and second
vents formed at two levels and spaced apart respectively such that
the uniformity of a gas flow and exhaust flow within the chamber is
maintained, and being outer inserted to the cathode assembly and
coupled at its lower end part to an inner surface of the
chamber.
2. The device of claim 1, wherein the cathode liner comprises: a
baffle plate having the first vents radially arranged; a liner part
of a constant length coupled at its upper end to an inner
circumference of the baffle plate; and an exhaust part provided in
a lower end part of the liner part and coupled to the chamber, and
having the second vents radially arranged.
3. The device of claim 2, wherein the first vents of the baffle
plate are comprised of slots spaced apart and arranged at regular
intervals.
4. The device of claim 3, wherein an inner circumference of the
baffle plate is screw coupled at its several places to the upper
end surface of the liner part.
5. The device of claim 2, wherein the exhaust part comprises: an
exhaust plate having the second vents through provided at a
constant interval, the second vents being provided to be slope at a
constant angle in an outside direction; and a coupling plate
extending outside along an outer circumference of a lower end part
of the exhaust plate and being screw coupled to the chamber.
6. The device of claim 5, wherein a control plate sliding and
rotating is provided on an upper surface of the exhaust plate, and
the control plate has a plurality of control ports arranged and
formed corresponding to the plurality of second vents to
simultaneously control aperture ratios of the second vents.
7. The device of claim 5, wherein a plurality of individual control
plates are provided on the upper surface of the exhaust plate to be
slidable on an upper part of the exhaust plate to control each of
the aperture ratios of the plurality of second vents.
8. The device of claim 5, further comprising a gasket for
preventing a leakage of a reaction gas at a lower side surface of
the coupling plate.
9. The device of claim 1, wherein the cathode liner is coated with
aluminum oxide (Al.sub.2O.sub.3), yttrium oxide (Y.sub.2O.sub.3).
Description
CROSS REFERENCE
[0001] This application claims foreign priority under Paris
Convention and 35 U.S.C. .sctn.119 to Korean Patent Application No.
10-2009-0076043, filed Aug. 18, 2009 with the Korean Intellectual
Property Office.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention relates to a plasma etching device for
treating a large size wafer. More particularly, the present
invention relates to a plasma etching device for improving plasma
uniformity by outer inserting an integral cathode liner having a
plurality of first vents and second vents formed at two levels
respectively to be spaced apart, to a cathode assembly such that
the uniformity of a gas flow and exhaust flow of a reaction gas
within a chamber is maintained and simultaneously, preventing a
flickering phenomenon by grounding a lower end part of the integral
cathode liner to the chamber.
[0004] 2. Description of the Related Art
[0005] Generally, a large size wafer used for a semiconductor
integrated circuit device, a glass substrate that is a key part
used for a Liquid Crystal Display (LCD), etc. are to form an
ultra-minute structure of a desired form and form a circuit or thin
film layer of a complex structure, by forming several thin film
layers on a surface and selectively removing only part of the thin
film layers. At this time, thin film manufacturing is carried out
through many manufacturing processes such as a rinse process, a
deposition process, a photolithography process, a plating process,
an etching process, etc.
[0006] The above various treatment processes are mainly carried out
within the chamber or reaction furnace capable of isolating a wafer
or substrate from the external.
[0007] Among the above processes, particularly, the etching process
is a process of removing desired materials from a wafer surface
through a plasma chemical reaction by jetting a reaction gas (e.g.,
carbon tetrafluoride (CF.sub.4), chlorine gas (Cl.sub.2), hydrogen
bromide (HBr), etc.) inside the chamber or reaction furnace. The
etching process is a process of selectively removing a portion not
covered with a photoresist using a photoresist pattern as a mask,
and forming a minute circuit on the substrate.
[0008] Accordingly, because it is of most significance in the
etching process to maintain etching uniformity for the whole
substrate surface, plasma should be allowed to be uniformly formed
within the chamber and get in contact with the whole substrate
surface for the sake of improving the etching uniformity and
preventing a process error.
[0009] In a conventional plasma etching device, in order to secure
plasma uniformity within a chamber, a baffle plate is installed to
have a plurality of vents formed in an outer circumference of a
cathode assembly, a pumping exhaust part is installed below the
chamber, and then, an exhaust pump is operated to pumping exhaust a
by-product such as a reaction gas within the chamber, a polymer, a
particle, etc. By doing so, the conventional plasma etching device
secures the plasma uniformity through a uniform exhaust of the
reaction gas within the chamber.
[0010] That is, the by-product such as the reaction gas, etc. is
continuously uniformly discharged outside the chamber such that the
plasma within the chamber uniformly diffuses on the substrate with
no resistance of the reaction gas, the by-product, etc.
[0011] However, the conventional plasma etching device of the above
structure has the following problems.
[0012] Firstly, because the reaction gas, the polymer, or the
particle generated after plasma reaction is pump exhausted through
one baffle plate, there is a limit in uniformly exhausting the
reaction gas, the by-product, etc. Thus, there is a problem that it
fails to secure the plasma uniformity within the chamber.
[0013] Secondly, because the baffle plate is not effectively
grounded to the chamber, there is a problem that there occurs a
plasma flickering phenomenon in which plasma between the vents is
irregularly flickered.
[0014] Thirdly, because of the absence of a control means for
controlling aperture ratios of the vents, there is a problem that
it is impossible to minutely control an etching rate of the
substrate through control of a gas flow or exhaust flow within the
chamber.
SUMMARY OF THE INVENTION
[0015] An aspect of exemplary embodiments of the present invention
is to address at least the problems and/or disadvantages and to
provide at least the advantages described below. Accordingly, an
aspect of exemplary embodiments of the present invention is to
maintain a uniformity of a gas flow and exhaust flow within a
chamber to improve plasma uniformity, by pump exhausting a reaction
gas, a polymer, or a particle generated after plasma reaction
through an integral cathode liner having a plurality of first vents
and second vents formed at two levels.
[0016] Another aspect of exemplary embodiments of the present
invention is to improve a ground force of a cathode liner, thus
preventing a plasma flickering phenomenon occurring between
vents.
[0017] A further aspect of exemplary embodiments of the present
invention is to secure an etching uniformity of the whole substrate
surface by making it possible to control aperture rates of second
vents and control plasma uniformity through a minute control of a
gas flow and exhaust flow within the chamber.
[0018] According to one aspect of the present invention, a plasma
etching device is provided. The device includes a chamber, a
cathode assembly, and an integral cathode liner. The chamber
provides a plasma reaction space. The cathode assembly is
positioned at an inner and central part of the chamber and supports
a substrate. The integral cathode liner has a plurality of first
vents and second vents formed at two levels and spaced apart
respectively such that the uniformity of a gas flow and exhaust
flow within the chamber is maintained, and is outer inserted to the
cathode assembly and coupled at its lower end part to an inner
surface of the chamber.
[0019] The cathode liner includes a baffle plate having the first
vents radially arranged, a liner part of a constant length coupled
at its upper end to an inner circumference of the baffle plate, and
an exhaust part provided in a lower end part of the liner part and
coupled to the chamber, and having the second vents radially
arranged.
[0020] The first vents of the baffle plate are comprised of slots
spaced apart and arranged at regular intervals.
[0021] An inner circumference of the baffle plate is screw coupled
at its several places to the upper end surface of the liner
part.
[0022] The exhaust part includes an exhaust plate having the second
vents through provided at a constant interval, the second vents
being provided to be slope at a constant angle in an outside
direction, and a coupling plate extending outside along an outer
circumference of a lower end part of the exhaust plate and being
screw coupled to the chamber.
[0023] A control plate sliding and rotating is provided on an upper
surface of the exhaust plate, and the control plate has a plurality
of control ports arranged and formed corresponding to the plurality
of second vents to simultaneously control aperture ratios of the
second vents.
[0024] A plurality of individual control plates are provided on the
upper surface of the exhaust plate to be slidable on an upper part
of the exhaust plate to control each of the aperture ratios of the
plurality of second vents.
[0025] The device further includes a gasket for preventing a
leakage of a reaction gas at a lower side surface of the coupling
plate.
[0026] The cathode liner is coated with aluminum oxide
(Al.sub.2O.sub.3), yttrium oxide (Y.sub.2O.sub.3).
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The above and other objects, features and advantages of the
present invention will become more apparent from the following
detailed description when taken in conjunction with the
accompanying drawings in which:
[0028] FIG. 1 is a schematic side diagram illustrating a plasma
etching device according to the present invention;
[0029] FIG. 2 is an exploded perspective diagram illustrating a
cathode liner according to an exemplary embodiment of the present
invention;
[0030] FIG. 3 is a perspective diagram illustrating a cathode liner
according to an exemplary embodiment of the present invention;
and
[0031] FIG. 4 is a partial exploded perspective diagram
illustrating a cathode liner according to another exemplary
embodiment of the present invention.
[0032] Throughout the drawings, the same drawing reference numerals
will be understood to refer to the same elements, features and
structures.
DESCRIPTION OF SPECIFIC EMBODIMENTS
[0033] Exemplary embodiments of the present invention will now be
described in detail with reference to the annexed drawings. In the
following description, a detailed description of known functions
and configurations incorporated herein has been omitted for
conciseness.
[0034] A description of the present invention is made in detail
with reference to the accompanying drawings.
[0035] FIG. 1 is a schematic side diagram illustrating a plasma
etching device according to the present invention.
[0036] As illustrated in FIG. 1, the plasma etching device of the
present invention includes a chamber 1, a cathode assembly 10, and
a cathode liner 50.
[0037] The chamber 1 is to provide a plasma reaction space isolated
from the external. A gas injector 5 jetting a reaction gas is
installed at a top and center of the chamber 1. An exhaust port 8
is formed at a bottom and center of the chamber 1 to discharge a
reaction by-product such as a reaction gas, a polymer, a particle,
etc. to the external.
[0038] Also, the chamber 1 is grounded at its one side to the
external to convert the reaction gas within the chamber 1 into a
plasma state by a Radio Frequency (RF) power source 7.
[0039] The cathode assembly 10 is to form an electrode of the RF
power source 7 and simultaneously, support a wafer or substrate
(not shown) such that it can be positioned horizontally at a center
within the chamber 1.
[0040] The cathode assembly 10 connects with the RF power source 7,
and safely mounts the substrate on an upper surface thereof.
[0041] Thus, the RF power source 7 etching treats a substrate
surface by plasma by electrically discharging the reaction gas
jetted into the chamber 1 and converting the reaction gas into a
plasma state.
[0042] The cathode assembly 10 can include an electrostatic chuck
(not shown) for stably fixing the substrate and also, can install a
gas pipe (not shown) for circulating helium (He) gas, etc. to cool
the substrate.
[0043] The electrostatic chuck is a device for absorbing a target
by an electrical attractive force operating between an electrode
surface and the target.
[0044] The reaction gas is jetted inside the chamber 1 through the
gas injector 5 formed on the same line as a center of the cathode
assembly 10 in order for plasma to be uniformly formed on the
substrate surface.
[0045] Thus, the reaction gas converts into a plasma state within
the chamber 1 by the RF power source 7 and reacts with the
substrate surface to selectively etch the substrate, and is
discharged outside through an exhaust port 8 formed at a lower part
of the chamber 1.
[0046] The cathode liner 50 is outer inserted to the cathode
assembly 10 and installed. The cathode liner 50 is described in
detail with reference to FIGS. 2 and 3.
[0047] FIG. 2 is an exploded perspective diagram illustrating the
cathode liner 50 according to an exemplary embodiment of the
present invention. FIG. 3 is a perspective diagram illustrating a
combined state of the cathode liner 50.
[0048] The cathode liner 50 is an integral liner having a plurality
of first vents 22 and second vents 42 formed at two levels
respectively to be spaced apart such that a uniformity of a gas
flow and exhaust flow within the chamber is maintained. The cathode
liner 50 includes a baffle plate 20, a liner part 30, and an
exhaust part 40.
[0049] The baffle plate 20 is to make a plasma reaction gas remain
on the chamber 1 for a constant time and then discharge the plasma
reaction gas. As illustrated, the baffle plate 20 is installed such
that the baffle plate 20 is coupled to an upper end surface of the
cylindrical liner part 30 and is positioned on an outer
circumference surface of an upper end part of the cathode assembly
10.
[0050] Thus, an inner circumference surface of the baffle plate 20
is formed corresponding to an outer circumference surface of the
cathode assembly 10. An outer circumference surface of the baffle
plate 20 is formed corresponding to an inner circumference surface
of the chamber 1. So, the baffle plate 20 is horizontally installed
in a space part provided between the outer circumference surface of
the cathode assembly 10 and the inner circumference surface of the
chamber 1.
[0051] The baffle plate 20 is of a circular ring shape having a
constant thickness. An insertion hole 25 is through provided at a
center of the baffle plate 20 such that the cathode assembly 10 can
be inserted into the insertion hole 25.
[0052] An outer circumference of the baffle plate 20 is not limited
to a circular shape, and may be of a rectangular shape, etc.
according to a shape of the inner circumference surface of the
chamber 1.
[0053] Thus, the outer circumference surface of the baffle plate 20
is contact coupled along the inner circumference surface of the
chamber 1, and an inner circumference surface of the insertion hole
25 is contact coupled along the outer circumference surface of the
cathode assembly 10. So, a reaction space within the chamber 1 is
partitioned into an upper part and a lower part.
[0054] The baffle plate 20 has a plurality of combination holes 20b
spaced apart and installed along a circumference of the insertion
hole 25, and couples and fixes fixing bolts 20a to an upper end
surface of the liner part 30 using the combination holes 20b.
[0055] First vents 22 are provided in the baffle plate 20.
[0056] The first vents 22, parts through which the reaction gas
passes, are slots of constant lengths are radially spaced a
distance apart and are arranged at regular intervals.
[0057] The first vents 22 are not limited to a slot shape, and may
be formed in various shapes considering a plasma environment
condition.
[0058] The liner part 30 is outer inserted to the cathode assembly
10, and has a cylindrical shape opened at its upper and lower
parts.
[0059] The liner part 30 has an inner circumference surface formed
and contacting corresponding to the outer circumference surface of
the cathode assembly 10. Also, the liner part 30 has a plurality of
combination holes 30b provided in its upper end surface
correspondingly to the combination holes 20b provided in the baffle
plate 20. So, the liner part 30 is coupled by the fixing bolt 20a
to contact with a lower side surface of the circumference of the
insertion hole 25 of the baffle plate 20.
[0060] The exhaust part 40 is provided below the liner part 30.
[0061] The exhaust part 40 finally discharges the reaction gas, the
by-product, etc. passing through the baffle plate 20 to the exhaust
port 8 of the chamber 1. The exhaust part 40 includes an exhaust
plate 41 extending from a lower end part of the liner part 30, and
a coupling plate 45 extending outside from an outer circumference
surface of a lower end part of the exhaust plate 41.
[0062] The exhaust plate 41 is formed to be slope at a constant
angle outside from an outer circumference of the lower end part of
the liner part 30. The second vents 42 are arranged at regular
intervals.
[0063] The second vents 42 are not limited to a rectangular shape
as illustrated, and may be through provided in various shapes such
as a circular shape, a long-hole shape, etc.
[0064] The coupling plate 45 extends in a horizontal direction by a
constant distance from the outer circumference of the lower end
part of the exhaust plate 41. The coupling plate 45 has a plurality
of combination holes 40b through provided to combine with fixing
bolts 40a for the sake of fixation to the chamber 1.
[0065] Thus, by firmly combining the coupling plate 45 to the
chamber 1 by the fixing bolts 40a and increasing a ground force,
the cathode liner 50 can prevent the plasma flickering phenomenon
from occurring in the vents due to an unstable ground of a baffle
plate as in a conventional plasma etching device.
[0066] A gasket 70 can be installed between the coupling plate 45
and the chamber 1 to prevent the unnecessary leakage of the
reaction gas.
[0067] The gasket 70 may be a metal spring of a circular ring
shape.
[0068] A control plate 60 can be further provided over the exhaust
plate 41 correspondingly to the exhaust plate 41 for the sake of
sliding rotation.
[0069] The control plate 60 is installed to be rotatably slid along
the exhaust plate 41 in a state where the control plate 60 is outer
inserted to the liner part 30 and is mounted on an upper surface of
the exhaust plate 41. The control plate 60 is provided in a ring
shape correspondingly to the exhaust plate 41.
[0070] The control plate 60 has control ports 62 through provided
at regular intervals correspondingly to the second vents 42 of the
exhaust plate 41.
[0071] Accordingly, as illustrated in FIG. 3, if the control plate
60 is rotated, an aperture ratio of each second vent 42 of the
exhaust plate 41 can be simultaneously controlled according to an
extent of overlapping with the control port 62.
[0072] That is, a worker rotates the control plate 60 at a suitable
angle as indicated by arrow 63, thereby controlling the aperture
ratio of the second vent 42 to the optimum condition and, at the
time of pumping exhaust, minutely controlling a gas flow and
exhaust flow within the chamber 1.
[0073] FIG. 4 illustrates a cathode liner 50 according to another
exemplary embodiment of the present invention. Besides a
construction of the control plate, this exemplary embodiment is
identical with the above exemplary embodiment and thus, only a
modified construction is described below.
[0074] As illustrated, a plurality of individual control plates 80
are installed on an upper surface of an exhaust plate 41.
[0075] The individual control plates 80 are installed corresponding
to the number of second vents 42 of the exhaust plate 41 to control
an aperture ratio of each second vent 42.
[0076] In detail, the individual control plates 80 are installed to
slide along the exhaust plate 41 while opening and closing the
second vents 42, respectively. By controlling each position of the
individual control plate 80, a worker can differently control each
of the aperture ratios of the second vents 42.
[0077] Guide members 82 and 83 may be installed at upper and lower
ends of the exhaust plate 41 to provide a guide rail (i.e., a
groove) for allowing upper and lower ends of the individual control
plate 80 to be inserted and slid such that the individual control
plate 80 can smoothly slide on an upper surface of the exhaust
plate 41.
[0078] The guide members 82 and 83 may be installed by spacing
apart band shape members from upper end and lower end surfaces of
the exhaust plate 41, respectively, such that a groove for
inserting an upper end and lower end of the individual control
plate 80 is provided in state where the individual control plate 80
is arranged on an upper surface of the exhaust plate 41.
[0079] Thus, by moving a position of the individual control plate
80 and minutely controlling the aperture ratio of each second vent
42, a worker can more minutely control the uniformity of a gas flow
and exhaust flow at the time of pumping exhausting a reaction gas,
a by-product, etc. within the chamber 1.
[0080] The individual control plates 80 are not limited to a form
illustrated in FIG. 4, and may be provided in a form of an
open/close door capable of being slidably installed in the second
vents 42 such as a common open/close door.
[0081] The cathode liner 50 can be coated with aluminum oxide
(Al.sub.2O.sub.3), yttrium oxide (Y.sub.2O.sub.3), etc. of
excellent corrosion resistance and abrasion resistance.
[0082] An operation process of the present invention is described
below with reference to FIG. 1.
[0083] If a reaction gas is jetted into the chamber 1 from the gas
injector 5 and the RF power source 7 is applied to the cathode
assembly 10, the reaction gas induces discharge electricity and
converts into a plasma state and then, etches a specific film of a
substrate surface.
[0084] At this time, the reaction gas constantly and uniformly
maintains a gas flow by the cathode liner 50 while sequentially
passing through the first and second vents 22 and 42 together with
a by-product, etc. as indicated by arrow 3. After that, the
reaction gas is discharged to the exhaust port 8.
[0085] Here, the reaction gas passes through the first vents 22 and
then is secondarily discharged out through the second vents 42. So,
a space part formed between the baffle plate 20 and the exhaust
part 40 performs a buffering role such that the gas flow and
exhaust flow within the chamber 1 can be more uniformly maintained
while being discharged.
[0086] Thus, by pumping exhausting a reaction gas, a polymer, or a
particle generated after plasma reaction through the integral
cathode liner 50 having the first vents 22 and the second vents 42,
the present invention can improve a non-uniform discharge by means
of a buffering effect of the space part operating between the
baffle plate 20 and the exhaust part 40. In addition, the present
invention can increase a ground force and prevent a plasma
flickering phenomenon because the cathode liner 50 is extended and
coupled to the chamber 1. Also, the present invention can control
the aperture ratio of the second vent 42 to minutely control the
plasma uniformity within the chamber 1.
[0087] For description convenience, the above exemplary embodiment
is merely described as an example and thus, is not limited to the
scope of claims and is all applicable to a plasma vacuum processing
equipment such as a sputter or Chemical Vapor Deposition (CVD) as
well.
[0088] As described above, the present invention has an effect of
being capable of securing the uniformity of plasma on a substrate
and securing the etching uniformity of the substrate by pumping
exhausting a reaction gas through an integral cathode liner of a
two-level structure, and minimizing a process error and improving a
process efficiency by preventing a plasma flickering phenomenon
capable of occurring between vents. The present invention has an
effect of being capable of manufacturing a high quality substrate
through the uniformity of an etching rate on the whole substrate
surface by making it possible to minutely control plasma uniformity
through aperture ratios of second vents.
[0089] While the invention has been shown and described with
reference to a certain preferred embodiment thereof, it will be
understood by those skilled in the art that various changes in form
and details may be made therein without departing from the spirit
and scope of the invention as defined by the appended claims.
* * * * *