U.S. patent application number 10/314233 was filed with the patent office on 2003-05-15 for member separating apparatus and processing apparatus.
Invention is credited to Miyakogawa, Toshikazu, Omi, Kazuaki, Sakaguchi, Kiyofumi, Yanagita, Kazutaka, Yonehara, Takao.
Application Number | 20030089455 10/314233 |
Document ID | / |
Family ID | 26430289 |
Filed Date | 2003-05-15 |
United States Patent
Application |
20030089455 |
Kind Code |
A1 |
Sakaguchi, Kiyofumi ; et
al. |
May 15, 2003 |
Member separating apparatus and processing apparatus
Abstract
This invention is to prevent a substrate from dropping when it
is transferred/received to/from a separating apparatus. The support
surfaces of substrate holding portions (22, 23) are made
horizontal, and a substrate (21) to be separated is mounted on one
substrate holding portion (22) in a horizontal state (2A). The
substrate holding portions (22, 23) are pivoted about rotary shafts
(26, 27), respectively, to make the support surfaces of the
substrate holding portions (22, 23) vertical so that the substrate
(21) is sandwiched by the substrate holding portions (22, 23) (2B)
The substrate holding portions (22, 23) are rotated about rotary
shafts (24, 25), respectively, and simultaneously, high-pressure,
high-speed water is ejected from an ejection nozzle (28) to
separate the substrate (21) into two substrates (21a, 21c). The
substrate holding portions (22, 23) are pivoted about the rotary
shafts (26, 27), respectively, to make the support surfaces
horizontal (2C). With this arrangement, the substrate can be
supported from the lower side and transferred in the horizontal
state.
Inventors: |
Sakaguchi, Kiyofumi;
(Yokohama-shi, JP) ; Yonehara, Takao; (Atsugi-shi,
JP) ; Omi, Kazuaki; (Yokohama-shi, JP) ;
Yanagita, Kazutaka; (Yokohama-shi, JP) ; Miyakogawa,
Toshikazu; (Ebina-shi, JP) |
Correspondence
Address: |
MORGAN & FINNEGAN, L.L.P.
345 Park Avenue
New York
NY
10154-0053
US
|
Family ID: |
26430289 |
Appl. No.: |
10/314233 |
Filed: |
December 9, 2002 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10314233 |
Dec 9, 2002 |
|
|
|
09275305 |
Mar 24, 1999 |
|
|
|
6540861 |
|
|
|
|
Current U.S.
Class: |
156/755 ;
257/E21.57 |
Current CPC
Class: |
H01L 21/67092 20130101;
Y10T 156/17 20150115; Y10T 156/1374 20150115; Y10T 156/1928
20150115; Y10T 156/1922 20150115; H01L 21/76259 20130101; Y10T
83/364 20150401 |
Class at
Publication: |
156/344 ;
156/584 |
International
Class: |
B32B 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 1, 1998 |
JP |
10-088970 |
Apr 1, 1998 |
JP |
10-088971 |
Claims
What is claimed is:
1. A separating apparatus for separating a member, comprising:
manipulation means for changing a direction of a major surface of
the member; and separation means for separating the member using a
stream of a fluid, wherein said manipulation means has a function
of manipulating the member to match the direction of the major
surface with a first direction and a function of manipulating the
member to match the direction of the major surface with a second
direction.
2. The apparatus according to claim 1, wherein said manipulation
means receives the member with the major surface whose direction
matches with the first direction, matches the direction of the
major surface with the second direction, and moves the member to a
position where said separation means can process the member, and
also matches a direction of a major surface of at least one member
of the members separated by said separation means with the first
direction.
3. The apparatus according to claim 1, wherein said manipulation
means receives the member with the major surface whose direction
matches with the first direction, matches the direction of the
major surface with the second direction, and moves the member to a
position where said separation means can process the member, and
also matches directions of major surfaces of members of the members
separated by said separation means with the first direction.
4. The apparatus according to claim 1, wherein the first and second
directions are substantially perpendicular to each other.
5. The apparatus according to claim 1, wherein the first direction
is a direction in which the major surface of the member is
substantially horizontal.
6. The apparatus according to claim 1, wherein the member to be
processed comprises a plate member, and said separation means cuts
the plate member in a direction of plane to separate the member
into two plate members.
7. The apparatus according to claim 6, wherein the second direction
is a direction in which the major surface of the plate member is
substantially vertical, and said separation means ejects the fluid
toward the plate member in the vertical direction to separate the
plate member into two plate members.
8. The apparatus according to claim 7, wherein the first direction
is a direction in which the major surface of the plate member is
substantially horizontal.
9. The apparatus according to claim 6, wherein said manipulation
means comprises a pair of holding means for holding the plate
member by sandwiching the member from two surface sides when said
separation means separates the plate member.
10. The apparatus according to claim 9, wherein each of said
holding means comprises chuck means for chucking the plate
member.
11. The apparatus according to claim 10, wherein said manipulation
means comprises pivot means for pivoting at least one of said pair
of holding means about a shaft parallel to a chuck surface of said
chuck means, and the direction of the major surface of the plate
member is changed by said pivot means.
12. The apparatus according to claim 10, wherein said manipulation
means comprises pivot means for pivoting said pair of holding means
about shafts parallel to chuck surfaces of said chuck means, and
the direction of the major surface of the plate member is changed
by said pivot means.
13. The apparatus according to claim 11, wherein the shaft as a
pivot center of said holding means is arranged at a position where
said pair of holding means do not interfere with each other.
14. The apparatus according to claim 1, further comprising rotation
means for rotating the member about a shaft perpendicular to the
major surface.
15. The apparatus according to claim 14, wherein said rotation
means comprises means for rotating the member when said separation
means separates the member.
16. The apparatus according to claim 14, wherein said separation
means separates the member using a stream of a liquid, and said
rotation means comprises means for rotating at least one of the
members separated by said separation means to remove the liquid
sticking to the member.
17. The apparatus according to claim 9, further comprising rotation
means for rotating at least one of said pair of holding means about
a shaft perpendicular to a holding surface.
18. The apparatus according to claim 17, wherein said rotation
means rotates said holding means when said separation means
separates the member.
19. The apparatus according to claim 17, wherein said separation
means separates the member using a stream of a liquid, and said
rotation means rotates said holding means to remove the liquid
sticking to the member held by said holding means after the member
is separated by said separation means.
20. The apparatus according to claim 1, further comprising a
chamber for covering said apparatus.
21. The apparatus according to claim 20, wherein said chamber has a
shutter capable of opening/closing.
22. The apparatus according to claim 21, further comprising
transfer means for transferring the member to be processed to said
manipulation means and receiving the separated member from said
manipulation means, said transfer means being arranged outside said
chamber and transferring/receiving the member to/from said
manipulation means while opening said shutter.
23. The apparatus according to claim 21, wherein said shutter is
closed at least when the member is separated by said separation
means.
24. The apparatus according to claim 22, further comprising
positioning means for positioning the member to be processed with
respect to said manipulation means.
25. The apparatus according to claim 1, wherein the member to be
separated has a fragile layer as a separation layer, and the
fragile layer is substantially parallel to the major surface of the
member.
26. A processing apparatus for processing a member, comprising:
manipulation means for changing a direction of a major surface of
the member; rotation means for rotating the member about a shaft
perpendicular to the major surface; and processing means for
processing the member while said rotation means is rotating the
member, wherein said manipulation means receives the member with
the major surface whose direction matches with a first direction,
matches the direction of the major surface with a second direction,
and moves the member to a position where said processing means can
process the member, and also matches the direction of the major
surface of the member which has been processed by said processing
means with the first direction.
27. The apparatus according to claim 26, wherein the first and
second directions are substantially perpendicular to each
other.
28. The apparatus according to claim 26, wherein the first
direction is a direction in which the major surface of the member
is substantially horizontal.
29. The apparatus according to claim 26, wherein said processing
means processes the member using a liquid, and said rotation means
rotates the member to remove the liquid sticking to the member
after the member is processed by said processing means.
30. A processing apparatus for processing a member, comprising:
holding means for holding the member; manipulation means for
changing a direction of a holding surface of said holding means;
processing means for processing the member held by said holding
means; and rotation means for rotating said holding means holding
the member about a shaft perpendicular to the holding surface when
said processing means is processing and/or has processed the
member, wherein said manipulation means matches the direction of
the holding surface with a first direction when said holding means
is to receive the member to be processed, matches the direction of
the holding surface of said holding means with a second direction
after said holding means receives and holds the member, and moves
said holding means to a position where said processing means can
process the member, and also matches the direction of the holding
surface of said holding means with the first direction after
processing by said processing means is complete.
31. The apparatus according to claim 30, wherein the first and
second directions are substantially perpendicular to each
other.
32. The apparatus according to claim 30, wherein the first
direction is a direction in which the major surface of the member
is substantially horizontal.
33. The apparatus according to claim 30, wherein said processing
means processes the member using a liquid, and said rotation means
rotates the member to remove the liquid sticking to the member
after the member is processed by said processing means.
34. A separating method of separating a member, comprising: the
reception step of receiving the member with a major surface whose
direction matches with a first direction; the manipulation step of
matching the direction of the major surface of the member with a
second direction; and the separation step of separating the member
using a stream of a fluid.
35. The method according to claim 34, further comprising the second
manipulation step of matching a direction of a major surface of at
least one member of the members separated in the separation step
with the first direction.
36. The method according to claim 34, further comprising the second
manipulation step of matching directions of major surfaces of the
members separated in the separation step with the first
direction.
37. The method according to claim 34, wherein the first and second
directions are substantially perpendicular to each other.
38. The method according to claim 34, wherein the first direction
is a direction in which the major surface of the member is
substantially horizontal.
39. The method according to claim 34, wherein the member to be
processed comprises a plate member, and the separation step
comprises cutting the plate member in a direction of plane to
separate the member into two plate members.
40. The method according to claim 39, wherein the second direction
is a direction in which the major surface of the plate member is
substantially vertical, and the separation step comprises ejecting
the fluid toward the plate member in the vertical direction to
separate the plate member into two plate members.
41. The method according to claim 40, wherein the first direction
is a direction in which the major surface of the plate member is
substantially horizontal.
42. The method according to claim 39, wherein the separation step
comprises holding the plate member by sandwiching the member from
two surface sides.
43. The method according to claim 34, wherein the separation step
comprises separating the member using the stream of a fluid while
rotating the member to be processed about a shaft perpendicular to
the major surface.
44. The method according to claim 34, wherein the separation step
comprises separating the member using a liquid, and the method
further comprises rotating at least one of the members separated to
remove the liquid sticking to the member after the member is
separated in the separation step.
45. The method according to claim 34, wherein the separation step
is executed in a chamber to prevent the fluid from scattering.
46. The method according to claim 34, wherein the member to be
processed has a fragile layer as a separation layer, and the
fragile layer is substantially parallel to the major surface of the
member.
47. The method according to claim 46, wherein the fragile layer
comprises a porous layer.
48. The method according to claim 46, wherein the fragile layer
comprises a layer having microcavity.
49. The method according to claim 46, wherein the member to be
processed is prepared by bonding at least two plate members, and at
least one of the two plate members comprises a semiconductor
substrate.
50. The method according to claim 49, wherein the semiconductor
substrate comprises a single-crystal silicon substrate.
51. The method according to claim 46, wherein the member to be
processed is prepared by bonding at least two plate members, and at
least one of the two plate members comprises an insulating
substrate.
52. The method according to claim 51, wherein the insulating
substrate comprises a quartz substrate.
53. The method according to claim 46, wherein the member to be
processed is prepared by bonding at least two plate members, and at
least one of the two plate members comprises a transparent
substrate.
54. The method according to claim 47, wherein the member to be
processed is prepared by bonding a first substrate sequentially
having a nonporous layer and a porous layer inward from a surface
to a second substrate via the nonporous layer.
55. The method according to claim 54, wherein the nonporous layer
has a single-crystal silicon layer.
56. The method according to claim 55, wherein the nonporous layer
has an insulating layer on the single-crystal silicon layer.
57. The method according to claim 56, wherein the insulating layer
is formed from a silicon oxide.
58. The method according to claim 54, wherein the second substrate
comprises an insulating substrate.
59. The method according to claim 54, wherein the second substrate
comprises a transparent substrate.
60. The method according to claim 54, wherein the second substrate
comprises a quartz substrate.
61. The method according to claim 54, wherein the porous layer is
formed by anodizing a single-crystal silicon substrate.
62. The method according to claim 48, wherein the member to be
processed is prepared by bonding a second substrate to a surface of
a first substrate incorporating a microcavity layer.
63. The method according to claim 62, wherein the microcavity layer
is formed by implanting ions into a single-crystal silicon
substrate.
64. The method according to claim 34, wherein water is used as the
fluid.
65. A semiconductor substrate manufacturing method comprising the
steps of: preparing a first substrate incorporating a porous layer
or a microcavity layer; bonding the first substrate to a second
substrate to prepare a bonded substrate stack; separating the
bonded substrate stack into a first substrate side and a second
substrate side using the porous layer or microcavity layer as a
separation region by using the separating method of claim 34; and
removing the porous layer or microcavity layer remaining on the
second substrate side.
66. The method according to claim 65, further comprising the step
of, after the bonded substrate stack is separated, removing the
porous layer or microcavity layer remaining on the first substrate
side to reuse the first substrate.
67. The method according to claim 65, wherein the porous layer is
formed by anodizing a semiconductor substrate.
68. The method according to claim 65, wherein the microcavity layer
is formed by implanting ions in a semiconductor substrate.
69. A semiconductor substrate formed by the method of claim 65.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a member separating
apparatus and processing apparatus, member separating method, and
semiconductor substrate manufacturing method.
[0003] 2. Description of the Related Art
[0004] A substrate (SOI substrate) having an SOI (Silicon On
Insulator) structure is known as a substrate having a
single-crystal Si layer on an insulating layer. A device using this
SOI substrate has many advantages that cannot be achieved by
ordinary Si substrates. Examples of the advantages are as
follows.
[0005] (1) The integration degree can be increased because
dielectric isolation is easy.
[0006] (2) The radiation resistance can be increased.
[0007] (3) The operating speed of the device can be increased
because the stray capacitance is small.
[0008] (4) No well step is necessary.
[0009] (5) Latch-up can be prevented.
[0010] (6) A completely depleted field-effect transistor can be
formed by thin film formation.
[0011] Since an SOI structure has the above various advantages,
researches have been made on its formation method for several
decades.
[0012] As one SOI technology, the SOS (Silicon On Sapphire)
technology by which Si is heteroepitaxially grown on a
single-crystal sapphire substrate by CVD (Chemical Vapor
Deposition) has been known for a long time. This SOS technology
once earned a reputation as the most matured SOI technology.
However, the SOS technology has not been put into practical use to
date because, e.g., a large amount of crystal defects are produced
by lattice mismatch in the interface between the Si layer and the
underlying sapphire substrate, aluminum that forms the sapphire
substrate mixes in the Si layer, the substrate is expensive, and it
is difficult to obtain a large area.
[0013] A variety of SOI technologies have been introduced next to
the SOS technology. Various techniques have been examined about
these SOI technologies aiming at decreasing crystal defects and
reducing the manufacturing cost. Examples of the techniques are as
follows. First, oxygen ions are implanted into a substrate to form
a buried oxide layer. Second, two wafers are bonded via an oxide
film, and one of the wafers is polished or etched to leave a thin
single-crystal Si layer on the oxide film. Third, hydrogen ions are
implanted from the surface of an Si substrate having an oxide film
to a predetermined depth, the substrate is bonded to another
substrate, a thin single-crystal Si layer is left on the oxide film
by heating or the like, and the bonded substrate (the other
substrate) is peeled.
[0014] The present applicant has disclosed a new SOI technology in
Japanese Patent Laid-Open No. 5-21338. In this technology, a first
substrate prepared by forming a nonporous single-crystal layer on a
single-crystal semiconductor substrate having a porous layer is
bonded to a second substrate via an insulating layer (SiO.sub.2).
After this, the substrates are separated at the porous layer,
thereby transferring the nonporous single-crystal layer to the
second substrate. Advantages of this technology are that the film
thickness uniformity of the SO layer is excellent, the crystal
defect density in the SOI layer can be reduced, the surface
planarity of the SOI layer is good, no expensive manufacturing
apparatuses with special specifications are required, and SOI
substrates having SOI films having a thickness of several hundred
.ANG. to 10 .mu.m can be manufactured by one manufacturing
apparatus.
[0015] The present applicant has also disclosed, in Japanese Patent
Laid-Open No. 7-302889, a technique of bonding the first and second
substrates, separating the first substrate from the second
substrate without destroying the first substrate, smoothing the
surface of the separated first substrate, and forming a porous
layer again to reuse the first substrate. In this technique, the
first substrate is not wasted, and therefore, the manufacturing
cost can be largely reduced, and the manufacturing process can also
be simplified.
[0016] To facilitate mass production using the above techniques,
factors to lower the yield must be minimized. For example, in a
series of processes of separating a bonded substrate stack at a
porous layer, it is important to avoid risks of substrate drop.
SUMMARY OF THE INVENTION
[0017] The present invention has been made in consideration of the
above situation, and has as its object to provide a separating
apparatus and method suitable to separate member such as
substrates, a processing apparatus suitable to process members such
as substrates, and a semiconductor substrate manufacturing method
using the separating method.
[0018] According to the present invention, there is provided a
member separating apparatus characterized by comprising
manipulation means for changing a direction of a major surface of a
member, and separation means for separating the member using a
stream of a fluid, wherein the manipulation means has a function of
manipulating the member to match the direction of the major surface
with a first direction and a function of manipulating the member to
match the direction of the major surface with a second
direction.
[0019] In the separating apparatus, the manipulation means
preferably receives the member with the major surface whose
direction matches with the first direction, matches the direction
of the major surface with the second direction, and moves the
member to a position where the separation means can process the
member, and also matches a direction of a major surface of at least
one member of the members separated by the separation means with
the first direction.
[0020] In the separating apparatus, the manipulation means
preferably receives the member with the major surface whose
direction matches with the first direction, matches the direction
of the major surface with the second direction, and moves the
member to a position where the separation means can process the
member, and also matches directions of major surfaces of members of
the members separated by the separation means with the first
direction.
[0021] In the separating apparatus, the first and second directions
are preferably substantially perpendicular to each other.
[0022] In the separating apparatus, the first direction is
preferably a direction in which the major surface of the member is
substantially horizontal.
[0023] In the separating apparatus, preferably, the member to be
processed comprises a plate member, and the separation means cuts
the plate member in a direction of plane to separate the member
into two plate members.
[0024] In the separating apparatus, preferably, the second
direction is a direction in which the major surface of the plate
member is substantially vertical, and the separation means ejects
the fluid toward the plate member in the vertical direction to
separate the plate member into two plate members.
[0025] In the separating apparatus, the first direction is
preferably a direction in which the major surface of the plate
member is substantially horizontal.
[0026] In the separating apparatus, the manipulation means
preferably comprises a pair of holding means for holding the plate
member by sandwiching the member from two surface sides when the
separation means separates the plate member.
[0027] In the separating apparatus, each of the holding means
preferably comprises chuck means for chucking the plate member.
[0028] In the separating apparatus, preferably, the manipulation
means comprises pivot means for pivoting at least one of the pair
of holding means about a shaft parallel to a chuck surface of the
chuck means, and the direction of the major surface of the plate
member is changed by the pivot means.
[0029] In the separating apparatus, preferably, the manipulation
means comprises pivot means for pivoting the pair of holding means
about shafts parallel to chuck surfaces of the chuck means, and the
direction of the major surface of the plate member is changed by
the pivot means.
[0030] In the separating apparatus, the shaft as a pivot center of
the holding means is preferably arranged at a position where the
pair of holding means do not interfere with each other.
[0031] The separating apparatus preferably further comprises
rotation means for rotating the member about a shaft perpendicular
to the major surface.
[0032] In the separating apparatus, the rotation means preferably
comprises means for rotating the member when the separation means
separates the member.
[0033] In the separating apparatus, preferably, the separation
means separates the member using a stream of a liquid, and the
rotation means comprises means for rotating at least one of the
members separated by the separation means to remove the liquid
sticking to the member.
[0034] The separating apparatus preferably further comprises
rotation means for rotating at least one of the pair of holding
means about a shaft perpendicular to a holding surface.
[0035] In the separating apparatus, the rotation means preferably
rotates the holding means when the separation mean separates the
member.
[0036] In the separating apparatus, preferably, the separation
means separates the member using a stream of a liquid, and the
rotation means rotates the holding means to remove the liquid
sticking to the member held by the holding means after the member
is separated by the separation means.
[0037] The separating apparatus preferably further comprises a
chamber for covering the apparatus.
[0038] In the separating apparatus, the chamber preferably has a
shutter capable of opening/closing.
[0039] The separating apparatus preferably further comprises
transfer means for transferring the member to be processed to the
manipulation means and receiving the separated member from the
manipulation means, the transfer means being arranged outside the
chamber and transferring/receiving the member to/from the
manipulation means while opening the shutter.
[0040] In the separating apparatus, the shutter is preferably
closed at least when the member is separated by the separation
means.
[0041] The separating apparatus preferably further comprises
positioning means for positioning the member to be processed with
respect to the manipulation means.
[0042] In the separating apparatus, preferably, the member to be
separated has a fragile layer as a separation layer, and the
fragile layer is substantially parallel to the major surface of the
member.
[0043] According to the present invention, there is also provided a
member processing apparatus characterized by comprising
manipulation means for changing a direction of a major surface of a
member, rotation means for rotating the member about a shaft
perpendicular to the major surface, and processing means for
processing the member while the rotation means is rotating the
member, wherein the manipulation means receives the member with the
major surface whose direction matches with a first direction,
matches the direction of the major surface with a second direction,
and moves the member to a position where the processing means can
process the member, and also matches the direction of the major
surface of the member which has been processed by the processing
means with the first direction.
[0044] In the processing apparatus, the first and second directions
are preferably substantially perpendicular to each other.
[0045] In the processing apparatus, the first direction is
preferably a direction in which the major surface of the member is
substantially horizontal.
[0046] In the processing apparatus, preferably, the processing
means processes the member using a liquid, and the rotation means
rotates the member to remove the liquid sticking to the member
after the member is processed by the processing means.
[0047] According to the present invention, there is also provided a
processing apparatus characterized by comprising holding means for
holding a member, manipulation means for changing a direction of a
holding surface of the holding means, processing means for
processing the member held by the holding means, and rotation means
for rotating the holding means holding the member about a shaft
perpendicular to the holding surface when the processing means is
processing and/or has processed the member, wherein the
manipulation means matches the direction of the holding surface
with a first direction when the holding means is to receive the
member to be processed, matches the direction of the holding
surface of the holding means with a second direction after the
holding means receives and holds the member, and moves the holding
means to a position where the processing means can process the
member, and also matches the direction of the holding surface of
the holding means with the first direction after processing by the
processing means is complete.
[0048] In the processing apparatus, the first and second directions
are preferably substantially perpendicular to each other.
[0049] In the processing apparatus, the first direction is
preferably a direction in which the major surface of the member is
substantially horizontal.
[0050] In the processing apparatus, preferably, the processing
means processes the member using a liquid, and the rotation means
rotates the member to remove the liquid sticking to the member
after the member is processed by the processing means.
[0051] According to the present invention, there is provided a
member separating method characterized by comprising the reception
step of receiving a member with a major surface whose direction
matches with a first direction, the manipulation step of matching
the direction of the major surface of the member with a second
direction, and the separation step of separating the member using a
stream of a fluid.
[0052] The separating method preferably further comprises the
second manipulation step of matching a direction of a major surface
of at least one member of the members separated in the separation
step with the first direction.
[0053] The separating method preferably further comprises the
second manipulation step of matching directions of major surfaces
of the members separated in the separation step with the first
direction.
[0054] In the separating method, the first and second directions
are preferably substantially perpendicular to each other.
[0055] In the separating method, the first direction is preferably
a direction in which the major surface of the member is
substantially horizontal.
[0056] In the separating method, preferably, the member to be
processed comprises a plate member, and the separation step
comprises cutting the plate member in a direction of plane to
separate the member into two plate members.
[0057] In the separating method, preferably, the second direction
is a direction in which the major surface of the plate member is
substantially vertical, and the separation step comprises ejecting
the fluid toward the plate member in the vertical direction to
separate the plate member into two plate members.
[0058] In the separating method, the first direction is preferably
a direction in which the major surface of the plate member is
substantially horizontal.
[0059] In the separating method, the separation step preferably
comprises holding the plate member by sandwiching the member from
two surface sides.
[0060] In the separating method, the separation step preferably
comprises separating the member using the stream of a fluid while
rotating the member to be processed about a shaft perpendicular to
the major surface.
[0061] In the separating method, preferably, the separation step
comprises separating the member using a liquid, and the method
further comprises rotating at least one of the members separated to
remove the liquid sticking to the member after the member is
separated in the separation step.
[0062] In the separating method, the separation step is preferably
executed in a chamber to prevent the fluid from scattering.
[0063] In the separating method, preferably, the member to be
processed has a fragile layer as a separation layer, and the
fragile layer is substantially parallel to the major surface of the
member.
[0064] In the separating method, the fragile layer preferably
comprises a porous layer.
[0065] In the separating method, the fragile layer preferably
comprises a layer having microcavity.
[0066] In the separating method, preferably, the member to be
processed is prepared by bonding at least two plate members, and at
least one of the two plate members comprises a semiconductor
substrate.
[0067] In the separating method, the semiconductor substrate
preferably comprises a single-crystal silicon substrate.
[0068] In the separating method, preferably, the member to be
processed is prepared by bonding at least two plate members, and at
least one of the two plate members comprises an insulating
substrate.
[0069] In the separating method, the insulating substrate
preferably comprises a quartz substrate.
[0070] In the separating method, preferably, the member to be
processed is prepared by bonding at least two plate members, and at
least one of the two plate members comprises a transparent
substrate.
[0071] In the separating method, the member to be processed is
preferably prepared by bonding a first substrate sequentially
having a nonporous layer and a porous layer inward from a surface
to a second substrate via the nonporous layer.
[0072] In the separating method, the nonporous layer preferably has
a single-crystal silicon layer.
[0073] In the separating method, the nonporous layer preferably has
an insulating layer on the single-crystal silicon layer.
[0074] In the separating method, the insulating layer is preferably
formed from a silicon oxide.
[0075] In the separating method, the second substrate preferably
comprises an insulating substrate.
[0076] In the separating method, the second substrate preferably
comprises a transparent substrate.
[0077] In the separating method, the second substrate preferably
comprises a quartz substrate.
[0078] In the separating method, the porous layer is preferably
formed by anodizing a single-crystal silicon substrate.
[0079] In the separating method, the member to be processed is
preferably prepared by bonding a second substrate to a surface of a
first substrate incorporating a microcavity layer.
[0080] In the separating method, the microcavity layer is
preferably formed by implanting ions into a single-crystal silicon
substrate.
[0081] In the separating method, water is preferably used as the
fluid.
[0082] According to the present invention, there is provided a
semiconductor substrate manufacturing method characterized by
comprising the steps of preparing a first substrate incorporating a
porous layer or a microcavity layer, bonding the first substrate to
a second substrate to prepare a bonded substrate stack, separating
the bonded substrate stack into a first substrate side and a second
substrate side using the porous layer or microcavity layer as a
separation region by using any one of the above separating methods,
and removing the porous layer or microcavity layer remaining on the
second substrate side.
[0083] The semiconductor substrate manufacturing method preferably
further comprises the step of, after the bonded substrate stack is
separated, removing the porous layer or microcavity layer remaining
on the first substrate side to reuse the first substrate.
[0084] In the semiconductor substrate manufacturing method, the
porous layer is preferably formed by anodizing a semiconductor
substrate.
[0085] In the semiconductor substrate manufacturing method, the
microcavity layer is preferably formed by implanting ions in a
semiconductor substrate.
[0086] Further objects, features and advantages of the present
invention will become apparent from the following detailed
description of the embodiments of the present invention with
reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0087] FIGS. 1A to 1E are views for explaining steps in
manufacturing an SOI substrate according to a preferred embodiment
of the present invention;
[0088] FIGS. 2A to 2C are views showing the principle of a
separating apparatus according to a preferred embodiment of the
present invention;
[0089] FIG. 3 is a schematic view showing the first arrangement of
a separating apparatus;
[0090] FIG. 4 is a schematic view showing the first arrangement of
the separating apparatus;
[0091] FIG. 5 is a schematic view showing the first arrangement of
the separating apparatus;
[0092] FIG. 6 is a schematic view showing the first arrangement of
the separating apparatus;
[0093] FIG. 7 is a schematic view showing the first arrangement of
the separating apparatus;
[0094] FIG. 8 is a view showing the first arrangement of an
adjustment mechanism for adjusting the clearance between substrate
holding portions;
[0095] FIG. 9 is a view showing the second arrangement of an
adjustment mechanism for adjusting the clearance between substrate
holding portions;
[0096] FIG. 10 is a schematic view showing the second arrangement
of an automatic separating apparatus;
[0097] FIG. 11 is a schematic view showing the second arrangement
of the automatic separating apparatus;
[0098] FIG. 12 is a schematic view showing the second arrangement
of the automatic separating apparatus; and
[0099] FIG. 13 is a schematic view showing the second arrangement
of the automatic separating apparatus.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0100] A preferred embodiment of the present invention will be
described below with reference to the accompanying drawings.
[0101] FIGS. 1A to 1E are views for explaining steps in
manufacturing an SOI substrate according to a preferred embodiment
of the present invention.
[0102] In the step shown in FIG. 1A, a single-crystal Si substrate
11 is prepared, and a porous Si layer 12 is formed on the substrate
surface by anodizing or the like. In the step shown in FIG. 1B, a
nonporous single-crystal Si layer 13 is formed on the porous Si
layer 12 by epitaxial growth. After this, the surface is oxidized
to form an SiO.sub.2 layer 15. With this process, a first substrate
10 is formed.
[0103] In the step shown in FIG. 1C, a second substrate 20
consisting of single-crystal Si is prepared. The first and second
substrates 10 and 20 are brought into contact with each other at
room temperature such that the second substrate 20 opposes an
insulating layer 15. After this, the first and second substrates 10
and 20 are bonded by anodic bonding, pressing, heating, or a
combination thereof. The insulating layer 15 may be formed on the
nonporous single-crystal Si layer 13, as described above, on the
second substrate 20, or on both of them as far as the state shown
in FIG. 1C is obtained when the first and second substrates are
brought into contact with each other.
[0104] In the step shown in FIG. 1D, the two substrates bonded to
each other are separated at the porous Si layer 12. Consequently, a
multilayered structure of a porous Si layer 12", single-crystal Si
layer 13, insulating layer 15, and the single-crystal Si substrate
20 is formed on the second substrate side (10"+20). On the first
substrate side (10'), a porous layer 12' is formed on the
single-crystal Si substrate 11.
[0105] After separation, the porous Si layer 12' left on the first
substrate is removed, and the substrate surface is planarized as
needed, thereby reusing the first substrate as the single-crystal
Si substrate 11 for forming the first substrate 10.
[0106] After the bonded substrates are separated, in the step shown
in FIG. 1E, the porous layer 12" on the surface on the second
substrate side (10"+20) is selectively removed. With this process,
a multilayered structure of the single-crystal Si layer 13,
insulating layer 15, and single-crystal Si substrate 20, i.e., a
substrate having an SOI structure is obtained.
[0107] As the second substrate, not only the single-crystal Si
substrate but also an insulating substrate (e.g., a quartz
substrate) or a transparent substrate (e.g., a quartz substrate)
can be used.
[0108] In this embodiment, to facilitate the process of bonding two
substrates and then separating them, the porous layer 12 having a
fragile structure is formed in the separation region. Instead of
the porous layer, for example, a microcavity layer may be formed. A
microcavity layer can be formed by implanting ions into a
semiconductor substrate.
[0109] In this embodiment, in the step shown in FIG. 1D, i.e., in
the process of separating a substrate (to be referred to as a
bonded substrate stack hereinafter) prepared by bonding two
substrates, a high-pressure liquid or gas (fluid) is injected
toward the separation region of the bonded substrate stack to break
the porous layer, thereby separating the bonded substrate stack
into two substrates.
[0110] [Principle of Separating Apparatus]
[0111] The principle of a separating apparatus according to a
preferred embodiment of the present invention will be described
first. The separating apparatus of this embodiment uses a water jet
method. Generally, the water jet method ejects high-speed,
high-pressure stream of water to an object to, e.g., process,
remove a coating film from the surface, or clean the surface
("History of Water Jet Machining Development", Journal of Water Jet
Technology Society of Japan, Vol. 1, No. 1, page 4 (1984)).
[0112] This separating apparatus ejects a high-speed, high-pressure
stream of a liquid or gas (fluid) to the porous layer (separation
region) of a bonded substrate stack in the direction of substrate
surface to selectively break the porous layer, thereby separating
the substrate stack at the porous layer. The stream will be
referred to as a "jet" hereinafter. The liquid or gas (fluid)
forming a jet will be referred to as a "jet medium". As the jet
medium, it is possible to use water, an organic solvent such as
alcohol, an acid such as hydrofluoric acid or nitric acid, an
alkali such as potassium hydroxide, other alkalis, a gas such as
air, nitrogen gas, carbonic acid gas, rare gas, or an etching gas
or other gases.
[0113] FIGS. 2A to 2C are views showing the principle of the
separating apparatus of the preferred embodiment of the present
invention. This separating apparatus has a pair of substrate
holding portions 22 and 23 for supporting a substrate. Rotary
shafts 24 and 25 are coupled to the substrate holding portions 22
and 23, respectively. The substrate holding portions 22 and 23 are
supported to freely pivot about rotary shafts 26 and 27,
respectively.
[0114] To separate a bonded substrate stack 21 into two substrates
21a and 21c, first, the substrate support surfaces of the substrate
holding portions 22 and 23 are made horizontal, as shown in FIG.
2A. The bonded substrate stack 21 is mounted at a predetermined
position on the substrate holding portion 22 and chucked on the
substrate support surface.
[0115] Next, as shown in FIG. 2B, the substrate holding portions 22
and 23 are pivoted about the rotary shafts 26 and 27, respectively,
to oppose them each other, so the bonded substrate stack 21 is
sandwiched and held by the substrate holding portions 22 and 23. At
this time, the substrate support surfaces of the substrate holding
portions 22 and 23 are vertical.
[0116] In this state, a jet medium (e.g., water) 29 is ejected from
an ejection nozzle 28 and injected into the separation region
(porous region) of the bonded substrate stack 21 while the bonded
substrate stack 21 is rotated about the rotary shafts 24 and 25.
With this operation, the bonded substrate stack 21 is separated
into the two substrates 21a and 21c. During this separating, the
bonded substrate stack 21 can be held without vacuum chuck.
[0117] As shown in FIG. 2C, the substrate holding portions 22 and
23 are pivoted about the rotary shafts 26 and 27, respectively,
until the substrate support surfaces become horizontal. During this
operation, the substrate 21a is chucked by the substrate holding
portion 22, and the substrate 21c is chucked by the substrate
holding portion 23.
[0118] Then a liquid such as water is used as the jet medium, the
separated substrates 21a and 21c can be dried by rotating the
substrate holding portions 22 and 23 about the rotary shafts 24 and
25 at a high speed, respectively.
[0119] In the state shown in FIG. 2B, i.e., when the bonded
substrate stack is sandwiched by the substrate holding portions 22
and 23, the rotary shafts 26 and 27 must be outside a space
(projection space) 30 formed by projecting the surface of the
bonded substrate stack 21 in the axial direction to prevent
interference between the substrate holding portions 22 and 23.
However, if a mechanism for moving one or both of the substrate
holding portions 22 and 23 in the horizontal direction is arranged,
the substrate holding portions 22 and 23 can be placed in the
projection space 30.
[0120] With the above-described separating apparatus, the bonded
substrate stack 21 can be transferred to the separating apparatus
in the horizontal state, and the separated substrates 21a and 21c
can be received from the separating apparatus in the horizontal
state. In the arrangement which allows substrate transfer in the
horizontal state, the substrates can be supported from the lower
side. Hence, risks of substrate drop during conveyance or transfer
are decreased.
[0121] Specific arrangements of the separating apparatus of the
preferred embodiment of the present invention will be described
below.
[0122] [First Arrangement of Separating Apparatus]
[0123] FIGS. 3 to 7 are schematic views showing the first
arrangement of a separating apparatus. A separating apparatus 100
comprises a pair of substrate manipulation portions 150 and 160 for
manipulating substrates.
[0124] The substrate manipulation portions 150 and 160 have
substrate holding portions 108 and 109 for supporting substrates,
respectively. The substrate holding portions 108 and 109 have
vacuum chuck grooves 108a and 109a as a mechanism for chucking the
substrate. The chucks 108a and 109a communicate with vacuum lines
extending through rotary shafts 106 and 107, respectively. The
vacuum lines are connected to an external vacuum line through a
rotary vacuum joint.
[0125] A bonded substrate stack 101 to be processed incorporates a
porous layer 101b as a fragile structure portion and is separated
into two substrates 101a and 101c at the porous layer 101b.
[0126] To separate the bonded substrate stack 101, the bonded
substrate stack 101 is sandwiched and supported vertically by the
substrate holding portions 108 and 109, as shown in FIG. 5.
[0127] In this separating apparatus 100, for example, the bonded
substrate stack is set such that the substrate 101a is present on
the first substrate side (10'), and the substrate 101c is present
on the second substrate side (10'+20) in FIG. 1D.
[0128] The substrate holding portion 108 is coupled to one end of
the rotary shaft 106 axially and rotatably supported by a shaft
support portion 102 through a bearing 104. The other end of the
rotary shaft 106 is coupled to a driving source 114. As the driving
source 114, for example, a motor is suitable. In separation
processing, the bonded substrate stack 101 is rotated by a
rotational force transmitted from the driving source 114. The
driving source 114 rotates the rotary shaft 106 at a rotation rate
designated in accordance with an instruction from a controller (not
shown).
[0129] On the other hand, the substrate holding portions 109 is
coupled to one end of the rotary shaft 107 axially and rotatably
supported by the shaft support portion 103 through a bearing 105.
The other end of the rotary shaft 107 is coupled to a driving
source 115. As the driving source 115, for example, a motor is
suitable. In separation processing, the bonded substrate stack 101
is rotated by a rotational force transmitted from the driving
source 115. The driving source 115 rotates the rotary shaft 107 in
synchronism with rotation of the rotary shaft 106 in accordance
with an instruction from the controller (not shown). The rotary
shafts 106 and 107 are rotated in synchronism with each other to
prevent twist of the bonded substrate stack 101.
[0130] Independent driving sources may be coupled to the rotary
shafts 106 and 107, respectively, as described above. However,
using a single driving source, the rotational force generated by
the driving source may be distributed to the rotary shafts 106 and
107. In this case, the rotary shafts 106 and 107 can easily be
rotated in synchronism with each other.
[0131] Alternatively, only one of the rotary shafts 106 and 107 may
be driven. For example, when only the driving source 114 for
driving the rotary shaft 106 is arranged, the rotary shaft 106,
substrate holding portion 108, bonded substrate stack 101,
substrate holding portion 109, and rotary shaft 107 integrally
rotate before separation of the bonded substrate stack 101. When
the bonded substrate stack 101 is separated into two substrates,
the members on the rotary shaft 107 side stop.
[0132] The shaft support portion 103 on the rotary shaft 107 side
incorporates a spring 111 for pressing the bonded substrate stack
101. Hence, the bonded substrate stack 101 receives a force in a
direction in which the substrate 101a is pressed against the
substrate 101c (negative direction of the X-axis). As a result,
after the bonded substrate stack 101 is separated into the two
substrates 101a and 101c by a jet from an ejection nozzle 110, and
even when the two substrates 101a and 101c are not vacuum-chucked
by the substrate holding portions 109 and 108, respectively, the
substrates 101a and 101c do not drop.
[0133] In this embodiment, the spring 111 applies a force in the
direction in which the substrate 101a is pressed against the
substrate 101c (negative direction of the X-axis). However, the
force may be applied in a direction in which the substrate 101a is
separated from the substrate 101c by changing the position of the
spring. In this case, when the bonded substrate stack 101 is
physically separated into the two substrates 101a and 101c by a jet
from the ejection nozzle 110, the substrate 101a is separated from
the substrate 101c.
[0134] The separating apparatus 100 has an adjustment mechanism for
adjusting the clearance between the substrate holding portions 108
and 109. Specific examples of the adjustment mechanism will be
described below.
[0135] FIG. 8 is a view showing the first arrangement of the
adjustment mechanism. The adjustment mechanism shown in FIG. 8 uses
an air cylinder 122. The air cylinder 122 is fixed to the shaft
support portion 103. When a piston rod 121 is retracted (driven),
the driving source (e.g., motor) 115 is pulled. When drive of the
piston rod 121 is canceled, the force of the spring 111 can be made
to act on the rotary shaft 107 to press the substrate.
[0136] FIG. 9 is a view showing the second arrangement of the
adjustment mechanism. The adjustment mechanism shown in FIG. 9 uses
an eccentric cam 131 and a motor. The eccentric cam 131 is coupled
to a motor (not shown). The clearance between the substrate holding
portions 108 and 109 is adjusted by moving a driving plate 132
coupled to the rear end of the driving source 115. The force of the
spring 111 acts on the rotary shaft 107 in the direction in which
the substrate is pressed. To hold the bonded substrate stack 101
and separate it into two substrates, the eccentric cam 131 is
pivoted in a direction in which restriction of the driving plate
132 by the eccentric cam 131 is canceled, i.e., in a direction in
which a gap is formed between the eccentric cam 131 and driving
plate 132. With this operation, the pressing force of the spring
111 can be made to act on the bonded substrate stack 101.
[0137] Even when a spring acting in a direction in which the bonded
substrate stack 101 is pulled is arranged in place of the spring
111, an adjustment mechanism for adjusting the clearance between
the substrate holding portions 108 and 109 is necessary. In this
case, the adjustment mechanism is used to push the substrate
holding portion 109 until it comes in contact with the bonded
substrate stack 101 to chuck the bonded substrate stack 101 on the
substrate support surface of the substrate holding portion 109.
[0138] The separating apparatus 100 has driving sources (e.g.,
motors) 151 and 161 for rotating rotary shafts 112 and 113 to pivot
the substrate manipulation portions 150 and 160, respectively. The
driving sources 151 and 161 are fixed to, e.g., the main body frame
of the separating apparatus 100.
[0139] As shown in FIG. 3, in the separating apparatus 100, the
substrate manipulation portions 150 and 160 can be pivoted about
the rotary shafts 112 and 113 by the driving sources 151 and 161 to
make the substrate support surfaces of the substrate holding
portions 108 and 109 horizontal or vertical, respectively.
[0140] Instead of preparing two driving sources for the substrate
manipulation portions 150 and 160, respectively, a single driving
source may be arranged. In this case, the output from the driving
source is distributed to drive the substrate manipulation portions
150 and 160.
[0141] In the separating apparatus 100, the rotary shafts 112 and
113 are placed outside the space (projection space) formed by
projecting the bonded substrate stack 101 in the axial direction
when the bonded substrate stack 101 is sandwiched (supported
vertically) by the substrate holding portions 108 and 109. In
addition, the rotary shafts 112 and 113 are arranged in a direction
parallel to the substrate support surfaces of the substrate holding
portions 108 and 109 (Y-axis direction). Hence, the substrate
manipulation portions 150 and 160 operate without interfering each
other, and the bonded substrate stack 101 does not damage the
separated substrates 101a and 101c.
[0142] Even when the rotary shafts 112 and 113 are placed in the
projection space, interference between the substrate manipulation
portions 150 and 160 can be avoided by increasing the retreat
distance of the substrate holding portion 109 to the shaft support
portion 103 side.
[0143] A series of procedures of bonded substrate stack separation
processing by the separating apparatus 100 will be described
below.
[0144] First, as shown in FIG. 3, the substrate manipulation
portions 150 and 160 are driven by the driving sources 151 and 161
to make the substrate support surfaces of the substrate holding
portions 108 and 109 horizontal, respectively. The substrate
holding portion 109 is retracted into the shaft support portion 103
by the adjustment mechanism shown in FIG. 8 or 9, as shown in FIG.
3. In this state, the bonded substrate stack 101 is mounted on the
substrate holding portion 108, and the pressure in the grooves 108a
is reduced to chuck the bonded substrate stack 101 on the substrate
support surface. The bonded substrate stack 101 is preferably
mounted on the substrate holding portion 108 such that the center
of the bonded substrate stack matches with the center of the
substrate holding portion 108.
[0145] Next, as shown in FIG. 4, the substrate manipulation
portions 150 and 160 are pivoted by the driving sources 151 and 161
to make the substrate support surfaces of the substrate holding
portions 108 and 109 vertical, respectively.
[0146] As shown in FIG. 5, the substrate holding portion 109 is
pushed from the shaft support portion 103 by the action of the
spring 111, so the bonded substrate stack 101 is pressed by the
substrate holding portion 109. When the arrangement shown in FIG. 8
or 9 is employed, this operation can be realized by canceling
restriction of the rotary shaft 107 by the air cylinder 122 or
eccentric cam 131.
[0147] In this state, the bonded substrate stack 101 may be
vacuum-chucked by one or both of the substrate holding portions 108
and 109. When the pressing force of the spring 111 suffices, the
bonded substrate stack 101 can be held by only the pressing force
without vacuum chuck.
[0148] Next, the driving sources 114 and 115 are operated in
synchronism to rotate the bonded substrate stack 101. A jet medium
(e.g., water) is compressed and supplied to the ejection nozzle 110
by a high-pressure pump (not shown) to inject the jet into the
porous layer 101b as the separation region of the bonded substrate
stack 101, i.e., in the vertical direction. When the jet is
injected while rotating the bonded substrate stack 101, the bonded
substrate stack 101 is separated into the two substrates 101a and
101c.
[0149] After the bonded substrate stack 101 is physically separated
into the two substrates, the substrate holding portions 108 and 109
is retreated to the shaft support portion 103 side by the
adjustment mechanism shown in FIG. 8 or 9, as shown in FIG. 6. With
this operation, the two substrates 101a and 101c which are
physically separated are separated spatially. When the substrates
101a and 101c are not chucked by the substrate holding portions 109
and 108, respectively, in separating the bonded substrate stack
101, the substrates 101a and 101c need be chucked by the substrate
holding portions 109 and 108, respectively, before the substrate
holding portion 109 is retreated to the shaft support portion 103
side.
[0150] As shown in FIG. 7, the substrate manipulation portions 150
and 160 are pivoted about the rotary shafts 112 and 113 by the
driving sources 151 and 161 to make the substrate support surfaces
of the substrate holding portions 108 and 109 horizontal,
respectively. The substrates 101a and 101c are held
horizontally.
[0151] When separation processing has been executed using a liquid
as a jet medium, the jet medium remains on the separated substrates
101a and 101c. The jet medium sticking to the substrates 101a and
101c is preferably removed by rotating the substrate holding
portions 108 and 109 by the driving sources 114 and 115,
respectively, to dry the substrates (spin drying). For spin drying,
a shielding plate for shielding the scattering jet medium is
preferably inserted between the two substrate manipulation portions
150 and 160.
[0152] The substrates 101a and 101c may be transferred to another
drying apparatus to dry them by the apparatus. When one of the
substrates is to be discarded, the substrate to be discarded need
not always be dried.
[0153] As described above, the separating apparatus 100 executes
separation processing while holding the bonded substrate stack
vertically. One reason for this is that when the jet is not ejected
in the vertical direction, the jet orbit is bent downward by
gravitation, and it becomes difficult to inject the jet to the
desired position (separation region) of the bonded substrate stack.
Another reason is that when the separation surface (porous layer)
of the bonded substrate stack is parallel to the direction of jet,
the jet can efficiently act on the separation surface, so the
efficiency of separation processing can be increased.
[0154] According to the separating apparatus 100 having the
substrate manipulation portions 150 and 160, separation processing
can be executed while holding the bonded substrate stack 101
vertically, and additionally, the bonded substrate stack can be
transferred to the separating apparatus in the horizontal state,
and the separated substrates can also be received in the horizontal
state. Since the substrates can be supported from the lower side
during substrate transfer, risks of substrate drop can be
decreased. On the other hand, if a mechanism for transferring the
bonded substrate stack to the separating apparatus in the vertical
state or a mechanism for receiving the separated substrates in the
vertical state is employed, the substrates may drop.
[0155] In addition, according to this separating apparatus, when
the substrate support surfaces of the substrate holding portions
108 and 109 are set horizontally, a wide space can be ensured on
the substrate support surfaces. This facilitates substrate transfer
or reception.
[0156] [Second Arrangement of Separating Apparatus]
[0157] This embodiment is related to an automatic separating
apparatus incorporating the separating apparatus 100 of the first
arrangement, which automatically executes a series of operations of
extracting a bonded substrate stack stored in a cassette,
transferring it to the separating apparatus 100, separating a
bonded substrate stack 101 in the separating apparatus 100, and
storing the separated substrates in another cassette.
[0158] FIGS. 10 to 13 are schematic views showing the second
arrangement of the automatic separating apparatus. More
specifically, FIG. 10 is a plan view schematically showing a state
wherein the bonded substrate stack 101 is set in the separating
apparatus 100, FIG. 11 is a view of the arrangement shown in FIG.
10 when viewed from one side, FIG. 12 is a plan view schematically
showing a state wherein the bonded substrate stack is to be
separated, and FIG. 13 is a view of the arrangement shown in FIG.
12 when viewed from one side.
[0159] The automatic separating apparatus of this embodiment
comprises the separating apparatus 100 of the first arrangement,
and a transfer apparatus 500 for transferring a bonded substrate
stack and separated substrates.
[0160] Preferably, the separating apparatus 100 is set in a chamber
400, and a shutter 503 is arranged between the chamber 400 and
transfer apparatus 500. Preferably, the shutter 503 is opened when
the bonded substrate stack 101 is to be set in the separating
apparatus 100 or separated substrates are to be extracted, and
closed during separation processing. With this arrangement, a jet
medium (e.g., water) can be prevented from scattering from the
chamber 400 during separation processing.
[0161] The transfer apparatus 500 comprises a transfer robot 501
for transferring the bonded substrate stack 101 and separated
substrates, and a positioning unit 507 for positioning the bonded
substrate stack 101 with respect to a substrate holding portion
108.
[0162] To execute separation processing, a cassette 504 storing one
or a plurality of bonded substrate stacks 101 and empty cassettes
505 and 506 for storing separated substrates 101a and 101c are set
at predetermined positions in the transfer apparatus 500. The
cassette 504 is set such that the bonded substrate stacks are held
horizontally and the opening portion faces the transfer robot 501.
The cassettes 505 and 506 are set such that the separated
substrates can be stored in the horizontal state and their opening
portions face the transfer robot 501.
[0163] The procedure of separation processing by the automatic
separating apparatus will be described below.
[0164] The operator sets the cassette 504 storing the bonded
substrate stacks 101 and the empty cassettes 505 and 506 at
predetermined positions in the transfer apparatus 500. When the
operator instructs to start separation processing through a control
panel (not shown), the automatic separating apparatus starts the
following series of processing operations.
[0165] First, the separating apparatus 100 pivots substrate
manipulation portions 150 and 160 to make the substrate support
surfaces horizontal, as shown in FIGS. 10 and 11.
[0166] The transfer robot 501 inserts a robot hand 502 having a
chuck mechanism under a corresponding bonded substrate stack 101 in
the cassette 504, chucks the lower surface of the bonded substrate
stack, and removes the bonded substrate stack 101.
[0167] The transfer robot 501 mounts the chucked bonded substrate
stack 101 on the support table of the positioning unit 507 and
cancel chuck. The positioning unit 507 aligns the central position
of the bonded substrate stack 101 to the reference position by two
guide members opposing each other. The transfer robot 501 chucks
the lower surface of the bonded substrate stack 101 on the support
table of the positioning unit 507, extends the robot hand 502
toward the substrate holding portion 108 of the separating
apparatus 100, and sets the bonded substrate stack 101 at a
predetermined position on the substrate holding portion 108. By
using the positioning unit 507, the bonded substrate stack 101 can
be positioned with respect to the substrate holding portion
108.
[0168] When the transfer robot 501 is to set the bonded substrate
stack 101 on the substrate holding portion 108, the shutter 503 is
open.
[0169] Each bonded substrate stack 101 can be set at a correct
position on the substrate holding portion 108 by positioning each
bonded substrate stack 101 by the positioning unit 507. Since the
center of the bonded substrate stack 101 can be matched with the
central axis of a rotary shaft 106, the distance between an
ejection nozzle 110 and the side surface of the bonded substrate
stack 101 is kept unchanged while the bonded substrate stack 101 is
rotated and separated. Hence, the jet can be made to uniformly act
along the entire circumference of the bonded substrate stack
101.
[0170] When setting of the bonded substrate stack 101 on the
substrate holding portion 108 is complete, the transfer robot 501
retracts the robot hand 502, and then, the shutter 503 is
closed.
[0171] In the separating apparatus 100, the substrate manipulation
portions 150 and 160 are pivoted by driving sources 151 and 161 to
make the bonded substrate stack 101 vertical, respectively, and the
bonded substrate stack 101 is sandwiched and vacuum-chucked by the
substrate holding portions 108 and 109.
[0172] The separating apparatus 100 executes separation processing.
More specifically, in the separating apparatus 100, the bonded
substrate stack 101 is rotated by driving sources 114 and 115', and
simultaneously, a jet is ejected and injected from the ejection
nozzle 110 into the separation region (porous region 101b) of the
bonded substrate stack 101. With this separation processing, the
bonded substrate stack 101 is separated into the two substrates
101a and 101c. The driving source 115' includes not only the
above-described driving source 115 but also the adjustment
mechanism shown in FIG. 8 or 9.
[0173] When the bonded substrate stack 101 is separated into the
two substrates 101a and 101c, the separating apparatus 100
separates the two substrates 101a and 101c by the above-described
adjustment mechanism. After this, the substrate manipulation
portions 150 and 160 are pivoted by the driving sources 151 and 161
to make the substrate support surfaces of the substrate holding
portions 108 and 109 horizontal, respectively.
[0174] By rotating the substrate holding portions 108 and 109 at
the driving sources 114 and 115' at a high speed, the jet medium
sticking to the separated substrates is removed (spin drying).
[0175] Subsequently, the shutter 503 is opened. The transfer robot
501 extends the robot hand 502 under the substrate 101c on the
substrate holding portion 108, holding the substrate 101c by
chucking its lower surface, and stores the substrate 101c in the
cassette 505. In the same way, the transfer robot 501 extends the
robot hand 502 under the substrate 101a on the substrate holding
portion 109, holds the substrate 101a by chucking its lower
surface, and stores the substrate 101a in the cassette 506.
[0176] With the above processing, separation processing of one
bonded substrate stack is ended. This automatic separating
apparatus can separate all bonded substrate stacks in the cassette
504 by repeating the above processing for all unprocessed bonded
substrate stacks.
[0177] According to this automatic separating apparatus, when the
cassette storing bonded substrate stacks and two empty cassettes
are prepared and set in the transfer apparatus 500, and execution
of separation processing is instructed, separation processing is
automatically executed, and two substrates which are separated and
dried are selectively stored in the two restoration cassettes.
[0178] As described above, even when separation processing is
automatically executed, the arrangement capable of transferring
substrates between the transfer apparatus and separating apparatus
in the horizontal state has a remarkable advantage.
[0179] This advantage is easy to understand in comparison with an
arrangement for transferring substrates between the transfer
apparatus and separating apparatus in the vertical state. In this
case, the substrate holding portion can hardly reliably chuck the
bonded substrate stack unless the transfer robot transfers the
substrate to the substrate holding portion while accurately holding
it vertically, and the bonded substrate stack may sometimes drop.
This also applies to reception of separated substrates by the
transfer robot. If the substrate holding surface of the robot hand
is not accurately parallel to the substrate, the robot hand can
hardly reliably chuck the substrate.
[0180] [Application Example of Separating Apparatus]
[0181] As an application example of the above separating apparatus,
a method of manufacturing an SOI substrate will be described below
with reference to FIGS. 1A to 1E.
[0182] As a single-crystal Si substrate 11, a p- or n-type (100)
single-crystal Si substrate having a thickness of 625 [.mu.m], a
diameter of 5 [inch], and a resistivity of 0.01
[.OMEGA..multidot.cm] was prepared. This single-crystal Si
substrate 11 was dipped in an HF solution and anodized to form a
porous Si layer 12 having a thickness of 12 [.mu.m] (FIG. 1A). The
anodizing conditions are as follows.
[0183] Current density: 7 [mA/cm.sup.2]
[0184] Anodizing solution: HF:H.sub.2O:C.sub.2H.sub.5OH=1:1:1
[0185] Process time: 11 [min]
[0186] This substrate was heated to 400[.degree. C.] in an oxygen
atmosphere and oxidized for 1 hr. With this process, inner walls of
pores in the porous Si layer 12 were covered with thermal oxide
films. Subsequently, a single-crystal Si layer 13 having a
thickness of 0.3 .mu.m was epitaxially grown on the porous Si layer
12 by CVD. The epitaxial growth conditions are as follows. Before
this process, the substrate may be baked in a hydrogen atmosphere
in the epitaxial furnace.
[0187] Source gas: SiH.sub.4
[0188] Carrier gas: H.sub.2
[0189] Temperature: 850 [.degree. C.]
[0190] Pressure: 1.times.10.sup.-2 [Torr]
[0191] Growth rate: 3.3 [nm/sec]
[0192] A 0.2-.mu.m thick SiO.sub.2 layer 15 was formed on the
single-crystal Si layer (epitaxial Si layer) 13 (FIG. 1B) A
single-crystal Si substrate 20 was separately prepared. The surface
of the SiO.sub.2 layer 15 and single-crystal Si substrate 20 were
brought into contact with each other at room temperature. After
this, a heat treatment was performed at a temperature of
1,100[.degree. C.] for 1 hr to bond the two substrates (FIG.
1C).
[0193] This bonded substrate stack was stored in the cassette 504
and set in the transfer apparatus 500 of the automatic separating
apparatus of the second arrangement, and separation processing was
executed (FIG. 1D). As a jet medium, pure water was used. The jet
diameter was set to be 0.2 [mm], and the pressure of water to be
ejected was set to be 350 [Kgf/cm.sup.2]. Separation processing was
performed while fixing the position of the ejection nozzle
immediately above the bonding interface. The bonded substrate stack
was rotated at a speed of about 8 [rpm].
[0194] Most bonded substrate stacks are completely separated when
they have made about five revolutions. However, in consideration of
variations between substrates, the automatic separating apparatus
was set to inject the jet while rotating the bonded substrate stack
for about 2 min.
[0195] Even after the bonded substrate stack was separated into two
substrates, the two substrates were still in contact with each
other due to the action of the spring 111. After a predetermined
time had elapsed from the start of bonded substrate stack
separation processing, one substrate holding portion 109 retreated
to the shaft support portion 103 side to spatially separate the two
substrates which had been physically separated. The substrates had
no flaws, cracks, or damages.
[0196] The substrate (10"+20) separated and stored in the cassette
505 was removed, and the porous Si layer on the surface was
selectively etched using an HF/H.sub.2O.sub.2/H.sub.2O-based
etchant. Since the etching rate for single-crystal Si was very low,
the etching amount of the single-crystal Si substrate as the
underlying layer of the porous Si layer could be neglected for
practical use. With this etching process, an SOI substrate having
the about 0.2-.mu.m thick single-crystal Si layer 13 on the
SiO.sub.2 film 15 could be formed (FIG. 1E).
[0197] It was confirmed that the surface of the resultant SOI
substrate, i.e., the surface of the single-crystal Si layer 13 had
no defects. Observation of the section of the single-crystal Si
layer 13 with a transmission electron microscope revealed that
crystal defects and the like did not increase in the process after
epitaxial growth, and satisfactory crystallinity was
maintained.
[0198] Instead of forming an SiO.sub.2 film on the surface on the
single-crystal Si layer (epitaxial layer) 13 side, even when 1) an
SiO.sub.2 film was formed not on the surface on the single-crystal
Si layer 13 side but on the side of an independently prepared
single-crystal Si substrate, or 2) SiO.sub.2 films were formed both
on the surface on the single-crystal Si layer 13 side and on the
side of a separately prepared single-crystal Si substrate, a
satisfactory SOI substrate could be formed.
[0199] The substrate (single-crystal Si substrate 11) on which the
porous Si layer was formed could be used as the first or second
substrate again by removing the porous Si layer on the surface and
planarizing the surface.
[0200] The substrate separating apparatus and method suitable to
manufacture an SOI substrate have been described above as the
preferred embodiments of the present invention. The separating
apparatus and method of the present invention can also be used to
separate or cut any other member. The member to be separated
preferably as a fragile separation region such as a porous
layer.
[0201] According to the present invention, for example, risks of
drop of a member such as a substrate can be decreased.
[0202] The present invention is not limited to the above
embodiments and various changes and modifications can be made
within the spirit and scope of the present invention. Therefore, to
apprise the public of the scope of the present invention, the
following claims are made.
* * * * *