US4409075A
Expired / Lapsed
US
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Method for cutting a semiconductor crystal into wafers
Assignee: Siemens AG
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Filing: 1981-07-15
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Granted: 1983-10-11
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Expires: 2001-07-15
Abstract
Abstract Method of separating a semiconductor crystal, in particular a rod-like semiconductor crystal, into wafers by first providing it with a masking layer of non-conducting material interrupted by stripes. The semiconductor crystal is biased as an anode and is immersed in an electrolyte which is provided with an electrode serving as the cathode. The oxide layers produced in the regions of the semiconductor crystal which are not masked, are removed mechanically.
Inventors
- 👤 Bernd Kolbesen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:32
CPC Classifications
C; C30; C30B; C30B29/00; C30B29/02; C30B29/06; B; B28; B28D; B28D5/00; C25; C25D; C25D11/00; C25D11/02; C25D11/32; C30B33/00; H; H10; H10P; H10P50/00; H10P50/60; H10P50/61; H10P50/613
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
136 words
An electrolytic-mechanical method of separating a semiconductor crystal, in particular a rod-like semiconductor crystal, into wafers, which comprises coating a semiconductor crystal with a masking layer of non-conducting material interrupted by stripes, immersing the semiconductor crystal with masking layer and stripes in an electrolyte provided with an electrode as a cathode and with the semiconductor crystal biased as an anode to form an electrolyzer, applying an electric current to the electrolyzer to produce oxide layers in the striped regions which are not masked by the masking layer, mechanically removing the oxide layers and separating the semiconductor crystal into a plurality of wafers, wherein a rod-like semiconductor crystal is used and the stripes interrupting the masking layer are arranged, parallel to each other and in ring-fashion, in planes approximately perpendicular to the longitudinal axis of the crystal.
Claim 2
Dependent Claim
136 words
An electrolytic-mechanical method of separating a semiconductor crystal, in particular a rod-like semiconductor crystal, into wafers, which comprises coating a semiconductor crystal with a masking layer of non-conducting material interrupted by stripes, immersing the semiconductor crystal with masking layer and stripes in an electrolyte provided with an electrode as a cathode and with the semiconductor crystal biased as an anode to form an electrolyzer, applying an electric current to the electrolyzer to produce oxide layers in the striped regions which are not masked by the masking layer, mechanically removing the oxide layers and separating the semiconductor crystal into a plurality of wafers, wherein a rod-like semiconductor crystal is used and the stripes interrupting the masking layer are arranged, parallel to each other and in ring-fashion, in planes approximately perpendicular to the longitudinal axis of the crystal.
Claim 3
Dependent Claim
19 words
Method according to claim 1, wherein the masking layer is interrupted in stripe-fashion by means of a photolithographic process.
Claim 4
Dependent Claim
16 words
Method according to claim 1, wherein the masking is interrupted in stripe-fashion by means of scribing.
Claim 5
Dependent Claim
18 words
Method according to claim 2, wherein the masking layer is interrupted in stripe-fashion by means of laser radiation.
Claim 6
Dependent Claim
18 words
Method according to claim 1, wherein the masking layer is interrupted by stripes 50 to 200 μm wide.
Claim 7
Dependent Claim
20 words
Method according to claim 5, wherein the masking layer is interrupted at spacings of at least 200 μm in stripe-fashion.
Claim 8
Dependent Claim
18 words
Method according to claim 1, wherein the masking layer is interrupted by stripes 80 to 120 μm wide.
Claim 9
Dependent Claim
12 words
Method according to claim 1, wherein the electrolyte is a fluoride-containing electrolyte.
Claim 10
Dependent Claim
12 words
Method according to claim 1, wherin the electrolyte is dilute hydrofluoric acid.
Claim 11
Dependent Claim
12 words
Method according to claim 1, wherein the masking layer is an oxide.
Claim 12
Dependent Claim
12 words
Method according to claim 10, wherein the oxide is SiO 2 .
Claim 13
Dependent Claim
14 words
Method according to claim 10, wherein the oxide is Al 2 O 3 .
Claim 14
Dependent Claim
15 words
Method according to claim 1, wherein the masking layer is Si 3 N 4 .
Claim 15
Dependent Claim
27 words
Method according to claim 1, wherein said oxide layers produced in the striped regions are removed by the mechanical action of at least one wire or blade.
Claim 16
Dependent Claim
21 words
Method according to claim 14, wherein the mechanical action is obtained by back-and forth movement of the wire or the blade.
Claim 17
Dependent Claim
19 words
Method according to claim 14, wherein the mechanical action is exerted perpendicularly to the surface of the semiconductor crystal.
Claim 18
Dependent Claim
23 words
Method according to claim 14, wherein said wire or blade is a metal selected from the group consisting of iron, copper and molybdenum.
Claim 19
Dependent Claim
16 words
Method according to claim 14, wherein several wires or blades are arranged parallel to each other.
Claim 20
Dependent Claim
19 words
Method according to calim 1, wherein the electrolyte is heated to decrease the time of procuding the oxide layers.
Claim 21
Dependent Claim
19 words
Method according to calim 1, wherein the electrolyte is heated to decrease the time of procuding the oxide layers.
Claim 22
Dependent Claim
11 words
Semiconductor wafer produced in accordance with the method of claim 1.
Claim 23
Dependent Claim
112 words
An electrolytic-mechanical method of separating a semiconductor crystal, in particular a rod-like semiconductor crystal, into wafers, which comprises coating a semiconductor crystal with a masking layer of non-conducting material interrupted by stripes, immersing the semiconductor crystal with masking layer and stripes in an electrolyte provided with an electrode as a cathode and with the semiconductor crystal biased as an anode to form an electrolyzer, applying an electric current to the electrolyzer to produce oxide layers in the striped regions which are not masked by the masking layer, mechanically removing the oxide layers and separating the semiconductor crystal into a plurality of wafers, wherein the semiconductor crystal is rotated about its longitudinal axis.
Claim 24
Dependent Claim
112 words
An electrolytic-mechanical method of separating a semiconductor crystal, in particular a rod-like semiconductor crystal, into wafers, which comprises coating a semiconductor crystal with a masking layer of non-conducting material interrupted by stripes, immersing the semiconductor crystal with masking layer and stripes in an electrolyte provided with an electrode as a cathode and with the semiconductor crystal biased as an anode to form an electrolyzer, applying an electric current to the electrolyzer to produce oxide layers in the striped regions which are not masked by the masking layer, mechanically removing the oxide layers and separating the semiconductor crystal into a plurality of wafers, wherein the semiconductor crystal is rotated about its longitudinal axis.
Claim 25
Dependent Claim
23 words
Method according to claim 21, wherein the semiconductor crystal is rotated at a speed in the range between about 1 and 10 rpm.
Claim 26
Dependent Claim
135 words
An electrolytic-mechanical method of separating a semiconductor crystal, in particular a rod-like semiconductor crystal, into wafers, which comprises coating a semiconductor crystal with a masking layer of non-conducting material interrupted by stripes, immersing the semiconductor crystal with masking layer and stripes in an electrolyte provided with an electrode as a cathode and with the semiconductor crystal biased as an anode to form an electrolyzer, applying an electric current to the electrolyzer to produce oxide layers in the striped regions which are not masked by the masking layer, mechanically removing the oxide layers and separating the semiconductor crystal into a plurality of wafers, wherein said oxide layers produced in the striped regions are removed by the mechanical action of at least one wire or blade, and wherein the semiconductor crystal is rotated about its longitudinal axis.
Claim 27
Dependent Claim
135 words
An electrolytic-mechanical method of separating a semiconductor crystal, in particular a rod-like semiconductor crystal, into wafers, which comprises coating a semiconductor crystal with a masking layer of non-conducting material interrupted by stripes, immersing the semiconductor crystal with masking layer and stripes in an electrolyte provided with an electrode as a cathode and with the semiconductor crystal biased as an anode to form an electrolyzer, applying an electric current to the electrolyzer to produce oxide layers in the striped regions which are not masked by the masking layer, mechanically removing the oxide layers and separating the semiconductor crystal into a plurality of wafers, wherein said oxide layers produced in the striped regions are removed by the mechanical action of at least one wire or blade, and wherein the semiconductor crystal is rotated about its longitudinal axis.
References Cited (Backward Citations)
SU201867A1
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US3128213A
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JPS5198973A
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US3962052A
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US4096619A
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US4193852A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-10 | 1987-04-11 | 1987-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-10 | 1991-04-11 | 1991-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-10 | 1995-04-11 | 1995-10-11 | $7700.00 | Window Closed / Lapsed |