EP0867919A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Semiconductor substrate and process for producing same
Assignee: Canon Inc
•
Filing: 1998-03-24
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Granted: —
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Expires: 2018-03-24
Abstract
Abstract In order to constantly produce a uniform SOI substrate without defect at a low cost by preventing destruction of a porous layer prior to separation of bonded substrates and effecting separation of the bonded substrates securely and easily, in a process for producing a semiconductor substrate comprising forming a non-porous semiconductor layer (13) on a first substrate (10) having porous layers (11, 12) formed on a surface thereof, forming an insulating layer (15) on a surface thereof, bonding the insulating layer (15) to a second substrate (14), and separating the porous layers (11, 12), thereby transferring the insulating layer (15) and the non-porous semiconductor layer (13) onto the surface of the second substrate (14), the first porous layer (11) is formed with a low porosity while the second porous layer is made thin to such extent as to be fragile to easily separate the first and the second substrates.
Inventors
- 👤 Kazuaki Ohmi
- 👤 Takao Yonehara
- 👤 Kiyofumi Sakaguchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 22:18
CPC Classifications
H; H10; H10P; H10P90/00; H10P90/19; H10P90/1904; H10P90/1906; H10P90/1914
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
138 words
A process for producing a semiconductor
substrate comprising the steps of: preparing a first substrate having a porous region
and a non-porous semiconductor layer arranged on the
porous region; bonding the non-porous semiconductor layer to a
second substrate; separating the bonded first and second substrates
at the porous region; and removing the porous region remaining on the
separated second substrate; wherein the porous region is formed such that the
porous region comprises a first porous layer adjacent
to the non-porous semiconductor layer and a second
porous layer having a higher porosity and a smaller
thickness than those of the first porous layer, and
such that the thickness of the second porous layer is
not more than 80% of the thickness of the first porous
layer and the porosity of the second porous layer is
from 30% to 60%.
Claim 2
Dependent Claim
16 words
The process according to claim 1, wherein the
separation takes place at the second porous layer.
Claim 3
Dependent Claim
18 words
The process according to claim 1, wherein the
porosity of the first porous layer is less than 30%.
Claim 4
Dependent Claim
26 words
The process according to claim 1, wherein the
thickness of the second porous layer is not more than
50% of that of the first porous layer.
Claim 5
Dependent Claim
20 words
The process according to claim 1, wherein the
thickness of the second porous layer is not more than 3
µm.
Claim 6
Dependent Claim
47 words
The process according to claim 1, further
comprising forming a porous region anew on a substrate
obtained by removing the porous region remaining on the
separated first substrate, utilizing the obtained
substrate again as the first substrate and bonding the
obtained substrate to another new second substrate.
Claim 7
Dependent Claim
52 words
The process according to claim 1, further
comprising utilizing a substrate obtained by removing
the porous region remaining on the separated first
substrate again as the second substrate, and bonding
the obtained substrate to another new first substrate
having a porous region and a non-porous semiconductor
layer provided on the porous region.
Claim 8
Dependent Claim
31 words
The process according to claim 1, wherein an
insulating layer is formed on a surface of the non-porous
semiconductor layer of the first substrate and
then bonded to the second substrate.
Claim 9
Dependent Claim
26 words
The process according to claim 1, wherein an
insulating layer is formed on a surface of the second
substrate and then bonded to the first substrate.
Claim 10
Dependent Claim
26 words
The process according to claim 1, further
comprising the step of removing the porous region
remaining on the non-porous semiconductor layer of the
separated second substrate.
Claim 11
Dependent Claim
37 words
The process according to claim 1, wherein the
first substrate is a semiconductor wafer with a
diameter of 6 inches or less, and wherein the second
porous layer has a thickness of 1 nm to 1 µm.
Claim 12
Dependent Claim
37 words
The process according to claim 1, wherein the
first substrate is a semiconductor wafer with a
diameter of 8 inches or more, and wherein the second
porous layer has a thickness of 1 µm to 3 µm.
Claim 13
Dependent Claim
11 words
A semiconductor substrate produced by the
process according to claim 1.
Claim 14
Dependent Claim
108 words
A composite member for a semiconductor
substrate, comprising a first substrate, a porous
region provided on the first substrate, a non-porous
semiconductor layer provided on the porous region, and
a second substrate provided on the non-porous
semiconductor layer; wherein the porous region comprises a first porous
layer adjacent to the non-porous semiconductor layer
and a second porous layer having a higher porosity and
a smaller thickness than those of the first porous
layer, and wherein the thickness of the second porous
layer is not more than 80% of the thickness of the
first porous layer and the porosity of the second
porous layer is from 30% to 60%.
Claim 15
Dependent Claim
19 words
The composite member according to claim 14,
wherein the porosity of the first porous layer is less
than 30%.
Claim 16
Dependent Claim
25 words
The composite member according to claim 14,
wherein the thickness of the second porous layer is not
more than that of the first porous layer.
Claim 17
Dependent Claim
21 words
The composite member according to claim 14,
wherein the thickness of the second porous layer is not
more than 3 µm.
Claim 18
Dependent Claim
38 words
The composite member according to claim 14,
wherein the first substrate is a semiconductor wafer
with a diameter of 6 inches or less, and wherein the
second porous layer has a thickness of 1 nm to 1 µm.
Claim 19
Dependent Claim
38 words
The composite member according to claim 14,
wherein the first substrate is a semiconductor wafer
with a diameter of 8 inches or more, and wherein the
second porous layer has a thickness of 1 µm to 3 µm.
Claim 20
Dependent Claim
31 words
The process according to claim 1, wherein
anodization is utilized with a change in the anodizing
current with the elapse of time to form a plurality of
layers different in porosity.
Claim 21
Dependent Claim
19 words
The process according to claim 20, wherein
the first porous layer has a thickness of at least 3
µm.
Claim 22
Dependent Claim
34 words
The process according to claim 1, wherein
when forming a plurality of porous layers different in
porosity by anodization, the composition of the
anodizing liquid is changed to effect anodization,
thereby varying the porosity.
Claim 23
Dependent Claim
37 words
The process according to claim 22, wherein
when changing the composition of the anodizing liquid,
at least a component of the anodizing liquid is
individually added to the anodizing liquid during the
anodization to vary the porosity.
Claim 24
Dependent Claim
38 words
The process according to claim 1, wherein
when forming a plurality of porous layers different in
porosity by anodization, both the anodizing liquid
composition and the anodizing current are changed to
effect the anodization, thereby varying the porosity.
Claim 25
Dependent Claim
65 words
The process according to claim 1, wherein the
anodizing current is stopped to flow in the course of
anodization; the substrate is taken out from the
anodizing liquid; the composition of the anodizing
liquid or the setting of the anodizing current is
changed; the substrate is again immersed in the
anodizing liquid; and the anodizing current is allowed
to flow to thereby re-start the anodization.
Claim 26
Dependent Claim
34 words
The process according to claim 1, wherein the
porous layer, adjacent to the non-porous semiconductor
layer and having porosity smaller than of other
regions, has an in-plane fluctuation in thickness not
more than 35%.
Claim 27
Dependent Claim
33 words
The process according to claim 1, wherein the
first porous layer has a thickness of 5 µm or more, and
wherein the second porous layer has a thickness of 3 µm
or less.
Claim 28
Dependent Claim
34 words
The composite member according to claim 14,
wherein the first porous layer has a thickness of 5 µm
or more, and wherein the second porous layer has a
thickness of 3 µm or less.
Claim 29
Independent Claim
46 words
A method of producing a semiconductor device
comprising steps of: producing a semiconductor substrate having a
non-porous semiconductor layer by the process of any of
claims 1 to 12, 20 to 27; and producing semiconductor device elements each
defined in and upon said non-porous semiconductor layer.
References Cited (Backward Citations)
No citation records indexed.
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