U.S. patent application number 11/983006 was filed with the patent office on 2008-10-02 for member for plasma etching device and method for manufacture thereof.
This patent application is currently assigned to Shin-Etsu Quartz Products Co., Ltd.. Invention is credited to Itsuo Araki, Kyoichi Inaki.
Application Number | 20080241412 11/983006 |
Document ID | / |
Family ID | 34362474 |
Filed Date | 2008-10-02 |
United States Patent
Application |
20080241412 |
Kind Code |
A1 |
Inaki; Kyoichi ; et
al. |
October 2, 2008 |
Member for plasma etching device and method for manufacture
thereof
Abstract
A member for a plasma etching device, which comprises a device
substrate comprising quartz glass, aluminum, alumite or a
combination thereof and, formed on the surface thereof, a coating
film of yttrium oxide or YAG having a film thickness of 10 .mu.m or
more and a variation in the thickness of 10% or less, and
preferably a surface roughness (Ra) of 1 .mu.m or less; and a
method for manufacturing the member for a plasma etching device,
which comprises a step of plasma-spraying yttrium oxide or YAG to
the surface of said device substrate or a step of fusing yttrium
oxide or YAG with an oxyhydrogen flame, followed by coating the
surface with the fused product, or a step of applying a solution
containing yttrium, a yttrium compound or YAG on the above surface,
followed by heating to fuse the resultant coating, or a combination
of the above steps, thereby forming a coating film of yttrium oxide
or YAG having a film thickness 10 .mu.m or more and a variation in
the thickness of 10% or less, and preferably a surface roughness
(Ra) of 1 .mu.m or less. The member for a plasma etching device is
capable of retaining high plasma resistance for a long period of
time, is free from the occurrence of the abnormal etching owing to
partial change of electric characteristics, and thus can be used
for a long time, in particular, even in the treatment of a large
semiconductor device of a 12 inch silicon wafer.
Inventors: |
Inaki; Kyoichi; (Tokyo,
JP) ; Araki; Itsuo; (Kikuchi-gun, JP) |
Correspondence
Address: |
JORDAN AND HAMBURG LLP
122 EAST 42ND STREET, SUITE 4000
NEW YORK
NY
10168
US
|
Assignee: |
Shin-Etsu Quartz Products Co.,
Ltd.
Shinjuku-ku
JP
|
Family ID: |
34362474 |
Appl. No.: |
11/983006 |
Filed: |
November 6, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10546798 |
Aug 23, 2005 |
|
|
|
PCT/JP2003/011768 |
Sep 16, 2003 |
|
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11983006 |
|
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Current U.S.
Class: |
427/448 ;
427/376.1; 427/376.2; 427/376.7; 427/376.8; 427/446; 427/453 |
Current CPC
Class: |
C23C 4/11 20160101; H01L
21/67069 20130101; C23C 4/18 20130101; H01J 37/32477 20130101; C23C
30/00 20130101; C23C 26/00 20130101 |
Class at
Publication: |
427/448 ;
427/453; 427/446; 427/376.2; 427/376.1; 427/376.7; 427/376.8 |
International
Class: |
B05D 5/02 20060101
B05D005/02; C23C 4/10 20060101 C23C004/10; C23C 4/06 20060101
C23C004/06; B05D 3/00 20060101 B05D003/00 |
Claims
1.-4. (canceled)
5. A method for producing a member for a plasma etching apparatus,
comprising forming a coating film of yttrium oxide or YAG having a
film thickness of 10 .mu.m or more and a thickness variance of 15%
or less formed on a surface of a member for a plasma etching
apparatus comprising quartz glass, aluminum, alumite or a
combination thereof by any one of the following methods: a method
of plasma-spraying yttrium oxide or YAG, a method of fusing yttrium
oxide or YAG powder by an oxyhydrogen flame and, then, performing
coating, a method or applying a solution in which yttrium, a
yttrium compound or YAG is dissolved and, then, performing
heat-fusing, and a combination thereof.
6. The method for producing the member for the plasma etching
apparatus according to claim 5, wherein a solution in which
yttrium, a yttrium compound or YAG is dissolved is applied on a
surface of a member for a plasma etching apparatus comprising
quartz glass, aluminum, alumite or a combination thereof and, then,
heat-fused to form a coating film of yttrium oxide or YAG and,
thereafter, further, yttrium oxide or YAG is plasma-sprayed.
7. The method for producing the member for the plasma etching
apparatus according to claims 5 or 6, wherein a ridge portion of
the member is subjected to rounding machining so as to have a size
or R 0.5 mm or more and, then, a coating film of yttrium oxide or
YAG is formed.
8. The method for producing the member for the plasma etching
apparatus according to claims 5 or 6, wherein a surface roughness
Ra of the coating Film of yttrium oxide or YAG is allowed to be 1
.mu.m or less.
9. The method for producing the member for the plasma etching
apparatus according to claims 5 or 6, wherein the member for the
plasma etching apparatus comprises quartz glass.
10. The method for producing the member for the plasma etching
apparatus according to claim 9, wherein after the surface is
subjected to a frost treatment, a coating film of yttrium oxide or
YAG is formed.
11. The method for producing the member for the plasma etching
apparatus according to claim 10, wherein the frost treatment is a
surface treatment using a chemical solution.
12. The method for producing the member for the plasma etching
apparatus according to claim 9, wherein a coating film of yttrium
oxide or YAG is formed on a surface of a quartz glass member in
which 1 to 10% by weight of yttrium oxide or YAG is previously
contained.
Description
TECHNICAL FIELD
[0001] The present invention relates to a member for use in a
plasma etching apparatus for a semiconductor device and,
particularly, to a member for a plasma etching apparatus coated
with a coating film of yttrium oxide or YAG and a manufacturing
method therefore.
BACKGROUND ART
[0002] Heretofore, in a production process of a semiconductor
device, an etching treatment has been performed on a thin film on
an Si wafer by making use of an ion or a radical generated in a
plasma. As for such plasma etching treatment method, there is, for
example, a method in which a thin film on a surface of an Si wafer
is etched by a chemical etching mechanism or a physical etching
mechanism, or a method in which the thin film is anisotropically
etched by electrically accelerating a speed of an ion and, then,
drawing it to the surface of the Si wafer. At the time of
performing the plasma etching treatment, a member or a container
(hereinafter referred to also as "member") containing quartz glass,
aluminum, alumite or the like has ordinarily been used. On this
occasion, there is a problem in that a surface of the member itself
is also etched and, then, a particle is generated, to thereby
contaminate a semiconductor device. For this account, a method in
which a tape containing a fluorocarbon resin or an engineering
plastic is applied on a surface of the member for the sake of
convenience or a method in which a coating film containing the
above-described resin is formed has been proposed. However, in the
method for applying the tape, since a film thickness of the tape
itself is small, etching resistance is not sufficient and also,
since a joint portion is formed by applying the tape, a plasma ion
is penetrated into a gap formed on this portion and, then, a
substrate is partially etched or, since it is difficult to
uniformly apply the tape on the surface, a gap is partially
generated between the substrate and the tape and, due to the gap,
an irregularity is generated on the surface and, then, an
irregularity of electric properties is generated on the surface
and, due to this irregularity, an insulation failure is partially
generated, to thereby cause such a problem as generating a pinhole
in the tape. Further, there is a drawback in that a contaminant is
released from an adhesive of the tape and, then, properties of the
Si wafer are deteriorated.
[0003] Further, as for the member which has been coated with the
conventional fluorocarbon resin or engineering plastic, since a
surface thereof tends to be roughened, the plasma is not well
generated and there is also a drawback in that a pinhole is
generated in the film or the like.
[0004] In order to solve these drawbacks of members containing
quartz glass, aluminum, alumina or the like, a member containing
ceramics which are excellent in plasma resistance is proposed in
JP-A-2001-118910 or the like. However, there is a problem in that a
crack or a bent is generated in the member containing the
above-described ceramics at the time of calcining and, then,
preparation of a large-sized member is not only difficult but also
expensive.
[0005] Thus, a first object of the present invention is to provide
a member for a plasma etching apparatus which has a high plasma
resistance, does not perform any abnormal etching to be caused by a
partial change of electrical properties and can be used for a long
period of time.
[0006] Further, a second object of the present invention is to
provide a member for a plasma etching apparatus which can handle
such a large-sized semiconductor device as being a 12-inch Si
wafer.
[0007] Still further, a third object of the present invention is to
provide a method for producing the above-described member for the
plasma etching apparatus.
DISCLOSURE OF THE INVENTION
[0008] The present invention relates to a member for a plasma
etching apparatus in which a coating film of yttrium oxide or
yttrium aluminum garnet (hereinafter, referred to also as "YAG")
having a thickness of 10 .mu.m or more, a film thickness variance
of 10% or less and, preferably, a surface roughness Ra of 1 .mu.m
or less is formed on a surface of a member containing quartz glass,
aluminum, alumite or a combination thereof, and also relates to a
method for producing a member for a plasma etching apparatus in
which a coating film of yttrium oxide or YAG is formed on a surface
of a member for a plasma etching apparatus containing quartz glass,
aluminum, alumite or a combination thereof by any one of a method
of plasma-spraying yttrium oxide or YAG, a method of fusing yttrium
oxide or YAG powder by an oxyhydrogen flame and, then, performing
coating by using the thus-fused article, a method of applying a
solution in which yttrium, a yttrium compound or YAG is dissolved
and, then, performing heat-fusing and a combination of these
methods.
BEST MODE FOR CARRYING OUT THE INVENTION
[0009] Hereinafter, the present invention is described in
detail.
[0010] A member for a plasma etching apparatus according to the
invention contains quartz glass, aluminum, alumite or a combination
thereof and has on a surface thereof a coating film of yttrium
oxide or YAG having a film thickness of 10 .mu.m or more, a film
thickness variance of 10% or less and, preferably, further, a
surface roughness Ra of 1 .mu.m or less. When the film thickness of
the above-described coating film of yttrium oxide or YAG is less
than 10 .mu.m, a pinhole tends to be generated and thickness of an
ridge portion becomes extremely small, to thereby generate a crack.
Further, when the surface roughness Ra is over 1 .mu.m, electric
properties on a surface of the coating film are partially changed,
to thereby generate an abnormal etching. Further, when the film
thickness variance is more than 10%, although the surface roughness
Ra of the coating film is 1 .mu.m or less, a large undulation is
generated and, then, due to this large undulation, electrical
properties of the coating film are deteriorated, to thereby easily
generate a pinhole by plasma. Preferably, the ridge portion of the
member is subjected to rounding machining so as to have a size of R
0.5 mm or more and, then, yttrium oxide of YAG is applied as a
coating film. By this rounding machining, the thickness of the
coating film is prevented from becoming small, to thereby suppress
generation of pinholes. As for the rounding machining; in a case of
a member containing quartz glass, a method of machining the ridge
portion by an oxyhydrogen flame, a method of mechanically polishing
the ridge portion by a grinder or the like or a method of blowing
crystalline silicon dioxide powder, silicone carbide powder or the
like on the ridge portion can be adopted, while, in a case of a
member containing aluminum or alumite, a method of mechanically
polishing the ridge portion by a grinder or the like or a method of
blowing crystalline silicon dioxide powder, silicone carbide powder
or the like on the ridge portion can be adopted.
[0011] As for the member for the above-described plasma etching
apparatus, a member in which a coating film of yttrium oxide or YAG
is formed on a member containing quartz glass is preferred. A
member in which a member is previously formed by using quartz glass
containing yttrium oxide or YAG in the range of from 1 to 10% by
weight and, then, on the thus-formed member, the coating film of
yttrium oxide or YAG is formed is more preferred. By performing
such arrangement as described above, difference of coefficient of
thermal expansion between the member and the coating film of
yttrium oxide or YAG becomes smaller, to thereby decrease film
separation, enhance plasma resistance, suppress generation of the
particle and expand a service life.
[0012] Next, an aspect of the method for producing the member for
the plasma etching apparatus according to the present invention is
described. Namely, there is a production method in which a starting
material containing quartz glass, aluminum, alumite or a
combination thereof is machined to form a member for a plasma
etching apparatus and, then, on the thus-formed surface of the
member, a coating film of yttrium oxide or YAG is formed by any one
of (i) a method of plasma-spraying yttrium oxide or YAG, (ii) a
method of fusing yttrium oxide or YAG powder in an oxyhydrogen
flame and, then, performing coating with the thus-fused article,
(iii) a method of applying a solution in which yttrium, a yttrium
compound or YAG is dissolved on a member, drying the thus-applied
solution and, then, heat-fusing the thus-dried article by the
oxyhydrogen flame (hereinafter, referred to also as "solution
application method"), and a combination of these methods. After a
coating film of yttrium oxide or YAG is formed by the solution
application method among these methods, when yttrium oxide or YAG
is plasma-sprayed on the thus-formed coating film, a film thickness
comes to be large and, further, a homogeneous yttrium oxide or YAG
coating film is formed, which is preferred. It is preferable that a
film thickness of the coating film of yttrium oxide or YAG is 10
.mu.m or more, a coating film variance is 10% or less and,
preferably, further, a surface roughness Ra is 1 .mu.m or less.
Particularly, when a member is prepared by using aluminum or
alumite, thermal resistance of the member is inferior and,
accordingly, it is preferable to cover yttrium oxide or YAG by any
one of the plasma-spraying method, the solution application method
or a combination of these methods. As for yttrium compounds to be
used by the solution application method, a hydroxide, a nitrate, a
carbonate, a sulfate, an oxalate thereof and the like are
mentioned. As for solvents for use in dissolving the yttrium,
yttrium compounds or YAG, pure water, an organic solvent is
mentioned. A coating solution is prepared by dissolving yttrium,
the yttrium compound or YAG. In the solution application method, in
order to prevent the generation of the pinhole, the solution is
preferably applied 3 times or more.
[0013] In the member for the plasma etching apparatus, when the
member contains quartz glass, a surface of the member is preferably
subjected to a roughening treatment prior to coating with yttrium
oxide or YAG. By such treatment, the coating film becomes difficult
to be slipped and, then, film separation can be prevented. The term
"frost treatment" as used herein means to provide irregularity on a
surface of quartz glass by a physical measure or a chemical
measure. As for such physical measures, there are a so-called
sandblast method in which crystalline silicon dioxide powder,
silicon carbide powder or the like is blown by compressed air, a
method in which crystalline silicon dioxide powder, silicon carbide
powder or the like is provided on a brush and, then, the surface
thereof is polished by using the resultant brush while being wet
with water and the like. Further, as for such chemical measures,
there are a chemical solution treatment method in which the member
is dipped in a mixed reagent of hydrogen fluoride and ammonium
fluoride and the like. Particularly, in the chemical measure, since
a micro-crack is not generated on the surface and mechanical
strength of quartz glass on the surface is not deteriorated, the
chemical measure is preferred. The surface roughness Ra to be
formed by the frost treatment is preferably in the range of from
0.1 to 10 .mu.m. In a case in which the surface roughness Ra is
beyond this range, adhesiveness between the coating film of yttrium
oxide or YAG and quartz glass is not sufficiently improved;
accordingly, the case is not preferred.
[0014] Hereinafter, the present invention is specifically described
with reference to embodiments but is not limited thereto.
EXAMPLE 1
[0015] A quartz glass chamber for a dry etching apparatus for a
12-inch Si wafer was prepared. A ridge portion of the chamber was
subjected to rounding machining so as to have a size of R 2 mm by
blowing crystalline silicon dioxide powder on an inner surface of
the thus-prepared quartz glass chamber. Further, by blowing
crystalline silicon dioxide powder (grain diameter: 100 to 300
.mu.m) also on an entire inner surface of the chamber, the inner
surface was allowed to be an irregular face having a surface
roughness Ra of 2.5 .mu.m and a Rmax of 20 .mu.m. On the
thus-formed inner surface of the quartz glass chamber,
Y.sub.2O.sub.3 was plasma-sprayed, to thereby form a Y.sub.2O.sub.3
coating film having a thickness of 40 .mu.m. A surface roughness Ra
of the coating film was 0.2 .mu.m and a film thickness variance
thereof was 12%.
[0016] Inside the above-described quartz glass chamber, a gas
mixture of CF.sub.4+O.sub.2 was allowed to be in a plasmatic
condition and, then, an oxide film of the 12-inch Si wafer was
etched. Although this chamber was used for 5 weeks, there was no
incidence in which the Y.sub.2O.sub.3 coating film was etched to
expose the quartz glass and there was no generation of an abnormal
particle on a surface of the Si wafer.
EXAMPLE 2
[0017] A quartz glass chamber of 12 inch was prepared by using
quartz glass in a same manner as in Example 1. A ridge portion of
this chamber was subjected to rounding machining by being heated by
an oxyhydrogen flame so as to have a size of R 1 mm. Further, the
quartz glass chamber was subjected to an etching treatment by using
a chemical solution of hydrofluoric acid and ammonium fluoride, to
thereby form an irregular face having an Ra of 1.5 .mu.m and a Rmax
of 13 .mu.m on an inner surface thereof. On the thus-formed inner
surface of the chamber, YAG was plasma-sprayed, to thereby form a
YAG coating film of 50 .mu.m. A surface roughness Ra of the YAG
coating film on this occasion was 0.5 .mu.m and a film thickness
variance thereof was 8%.
[0018] Inside the above-described quartz glass chamber, a gas
mixture of CF.sub.4+O.sub.2 was allowed to be in a plasmatic
condition and, then, an oxide film of the 12-inch wafer was etched.
Although this chamber was used for 5 weeks, there was no incidence
in which the YAG coating film was etched to expose the quartz glass
and there was no generation of an abnormal particle on a surface of
the Si wafer.
EXAMPLE 3
[0019] An aluminum cover for a dry etching apparatus for a 12-inch
Si wafer was prepared. A surface of the aluminum cover was
subjected to an alumite treatment. A ridge portion of the aluminum
cover was subjected to rounding machining so as to have a size of R
1 mm and, then, an outer surface thereof was plasma-sprayed with
Y.sub.2O.sub.3, to thereby form a Y.sub.2O.sub.3 coating film of
200 .mu.m. A surface roughness Ra of the Y.sub.2O.sub.3 coating
film on this occasion was 0.1 .mu.m and a film thickness variance
thereof was 15%.
[0020] Inside the etching apparatus provided with the aluminum
cover, a gas mixture of CF.sub.4+O.sub.2 was allowed to be in a
plasmatic condition and, then, an oxide film of the 12-inch wafer
was etched. Although this cover was used for 5 weeks, there was no
incidence in which the Y.sub.2O.sub.3 coating film was etched to
expose aluminum and there was no generation of an abnormal particle
on a surface of the Si wafer.
EXAMPLE 4
[0021] Quartz powder was blended with 5% by weight of
Y.sub.2O.sub.3 powder and, then, sufficiently homogeneously mixed
by a ball mill. The resultant starting material was fused in an
oxyhydrogen flame, to thereby prepare an ingot of quartz glass.
From the ingot which is a base material, a quartz glass chamber for
a dry etching apparatus of 12-inch Si wafer was prepared.
Crystalline silicon dioxide powder (100 to 300 .mu.m) was blown on
an inner surface of this chamber, to thereby form an irregular face
having a surface roughness Ra of 2.5 .mu.m and an Rmax of 20 .mu.m.
Then, Y.sub.2O.sub.3 was plasma-sprayed on the thus-formed inner
face of the chamber, to thereby obtain a Y.sub.2O.sub.3 coating
film having a thickness of 150 .mu.m. A surface roughness Ra of the
coating film was 0.5 .mu.m and a film thickness variance thereof
was 10%.
[0022] Inside the above-described quartz glass chamber, a gas
mixture of CF.sub.4+O.sub.2 was allowed to be in a plasmatic
condition and, then, an oxide film of the 12-inch Si wafer was
etched. Although this chamber was used for 12 weeks, there was no
incidence in which the Y.sub.2O.sub.3 coating film was etched to
expose the quartz glass and there was no generation of an abnormal
particle on a surface of the Si wafer.
EXAMPLE 5
[0023] A quartz glass chamber for a dry etching apparatus for a
12-inch Si wafer was prepared. A ridge portion of this chamber was
subjected to rounding machining by being heated by an oxyhydrogen
flame so as to have a size of R 1 mm. Further, an inside of the
chamber was subjected to an etching treatment by using a chemical
solution of hydrofluoric acid and ammonium fluoride, to thereby
form an irregular face having a surface roughness Ra of 2.5 .mu.m
and a Rmax of 20 .mu.m. On the thus-formed inner surface of the
chamber, a yttrium nitrate solution was applied 4 times, dried and,
then, heat-fused by the oxyhydrogen flame, to thereby obtain a
Y.sub.2O.sub.3 coating film of 50 .mu.m. A surface roughness Ra of
the coating film was 0.5 .mu.m and a film thickness variance
thereof was 8%.
[0024] Inside the above-described quartz glass chamber, a gas
mixture of CF.sub.4+O.sub.2 was allowed to be in a plasmatic
condition and, then, an oxide film of the 12-inch Si wafer was
etched. Although this chamber was used for 12 weeks, there was no,
incidence in which the Y.sub.2O.sub.3 coating film was etched to
expose the quartz glass and there was no generation of an abnormal
particle on a surface of the Si wafer.
COMPARATIVE EXAMPLE 1
[0025] A quartz glass chamber for a dry etching apparatus for a
12-inch Si wafer was prepared. Inside this quartz glass chamber, a
gas mixture of CF.sub.4+O.sub.2 was allowed to be in a plasmatic
condition and, then, an oxide film of the 12-inch Si wafer was
etched. When this chamber was used for 2 weeks, an abnormal
particle was generated on a surface of the Si wafer and,
accordingly, the chamber was stopped using for more than one
week.
COMPARATIVE EXAMPLE 2
[0026] An aluminum cover for a dry etching apparatus for a 12-inch
Si wafer was prepared. A surface thereof was subjected to an
alumite treatment. A polyimide tape of 125 .mu.m was attached to an
outer surface of the thus-treated aluminum cover. In an etching
apparatus provided with this aluminum cover, a gas mixture of
CF.sub.4+O.sub.2 was allowed to be in a plasmatic condition and,
then, an oxide film of an 8-inch wafer was etched. When this cover
was used for 2 weeks, a gap of the polyimide tape was abnormally
etched to expose aluminum and, then, irregularity was generated on
the surface thereof, to thereby partially accelerate etching and
generate a pinhole on the polyimide tape. 2 weeks later, the
polyimide tape was removed and a new polyimide tape was attached
again. When the resultant aluminum cover was set on the apparatus,
an abnormal contamination was noticed on the wafer and, then, the
apparatus was stopped using.
COMPARATIVE EXAMPLE 3
[0027] An aluminum cover for a dry etching apparatus for a 12-inch
Si wafer was prepared. A surface thereof was subjected to an
alumite treatment. In an etching apparatus provided with this
aluminum cover, a gas mixture of CF.sub.4+O.sub.2 was allowed to be
in a plasmatic condition and, then, an oxide film of the 12-inch Si
wafer was etched. When this cover was used for 2 weeks, the alumite
was removed 1 week after the start of the usage and generation of a
particle was noticed on a surface of the wafer and, then, the
apparatus was stopped using.
INDUSTRIAL APPLICABILITY
[0028] The member for the plasma etching apparatus according to the
present invention has a high plasma resistance and, further, is not
subjected to an abnormal etching on the basis of a partial change
of electric properties and, accordingly, can be used for a long
period of time. Particularly, even when the member is large enough
to handle a 12-inch Si, the above-described properties are
maintained and, then, it can be used for long period of time. This
member for the plasma etching apparatus can be manufactured in a
convenient manner by using any one of a method of spraying
Y.sub.2O.sub.3 or YAG, a method of applying a solution of yttrium
or a YAG compound and, then, performing oxidization by using an
oxyhydrogen flame, a method of fusing Y.sub.2O.sub.3 or YAG powder
and, then, performing coating by using the thus-fused article, a
combination of these methods and the like and, accordingly, is
industrially valuable.
* * * * *