US4383886A
Expired / Lapsed
US
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Method of manufacturing a semiconductor element
Assignee: Toshiba Corp
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Filing: 1981-11-05
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Granted: 1983-05-17
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Expires: 2001-11-05
Abstract
Abstract An improved semiconductor element-manufacturing method which saves a semiconductor wafer from the occurrence of cracks or damage during the manufacture of a semiconductor element and enables solder layers to be deposited without irregularities in the thickness. The method starts with the step of forming a first metal layer acting as an ohmic electrode on each side of the element regions of a semiconductor wafer in which a plurality of active elements are formed or on the whole surface of each side of the semiconductor wafer. Then a second metal layer which has an anticorrosive property and acts as a brazing material when the semiconductor element is mounted between a pair of electrodes is selectively deposited by electroplating on each of the element areas in the first metal layers. Finally, those portions of the semiconductor wafer which are interposed between the active elements are chemically etched off with the second metal layers used as masks to separate the semiconductor elements from each other, thereby producing a plurality of semiconductor elements, each of which has its surfaces coated with the first and second metal layers.
Inventors
- 👤 Kisaku Nakamura
- 👤 Eiji Jimi
- 👤 Haruyuki Goto
- 👤 Akio Hori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:02
CPC Classifications
H; H10; H10P; H10P54/00; H10D; H10D64/00; H10D64/01; H10D64/011; H10P14/00; H10P14/40; H10P14/46; H10W; H10W70/00; H10W70/20; H10W70/24; H10W72/00; H10W72/01; H10W72/012; H10W72/019; H10W72/20; H10W72/251; H10W72/50; H10W72/59; H10W72/90; H10W72/951; H10W72/952
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
151 words
A method of producing a semiconductor element, which comprises the steps of: forming a first metal layer acting as an ohmic electrode by wet plating on each side of the element sections of a semiconductor wafer in which a plurality of active elements are formed or the whole surface of each side of said wafer; selectively depositing by electroplating a single ply second metal layer which is anticorrosive and acts as a brazing material when a semiconductor element is mounted between a pair of electrodes, on each of the element areas in the first metal layers; and chemically etching off those portions of the semiconductor wafer which are interposed between the active elements with the second metal layers used as masks to separate the thus produced elements from each other, thereby producing a plurality of semiconductor elements, each of which has its surfaces coated with the first and second metal layers.
Claim 2
Independent Claim
151 words
A method of producing a semiconductor element, which comprises the steps of: forming a first metal layer acting as an ohmic electrode by wet plating on each side of the element sections of a semiconductor wafer in which a plurality of active elements are formed or the whole surface of each side of said wafer; selectively depositing by electroplating a single ply second metal layer which is anticorrosive and acts as a brazing material when a semiconductor element is mounted between a pair of electrodes, on each of the element areas in the first metal layers; and chemically etching off those portions of the semiconductor wafer which are interposed between the active elements with the second metal layers used as masks to separate the thus produced elements from each other, thereby producing a plurality of semiconductor elements, each of which has its surfaces coated with the first and second metal layers.
Claim 3
Independent Claim
155 words
A method of producing a semiconductor element which comprises the steps of: forming a first metal layer acting as an ohmic electrode by wet plating on each side of the element sections of a semiconductor wafer in which a plurality of active elements are formed or the whole surface of each side of said wafer; selectively depositing by electroplating a laminated second metal layer whose outermost layer at least is anticorrosive and which acts as a brazing material when the active element is mounted between a pair of electrodes, on each of the element areas in the first metal layers and; chemically etching off those portions of the semiconductor wafer which are interposed between the active elements with the second metal layers used as masks to separate the thus produced elements from each other, thereby producing a plurality of semiconductor elements, each of which has its surfaces coated with the first and second metal layers.
Claim 4
Independent Claim
155 words
A method of producing a semiconductor element which comprises the steps of: forming a first metal layer acting as an ohmic electrode by wet plating on each side of the element sections of a semiconductor wafer in which a plurality of active elements are formed or the whole surface of each side of said wafer; selectively depositing by electroplating a laminated second metal layer whose outermost layer at least is anticorrosive and which acts as a brazing material when the active element is mounted between a pair of electrodes, on each of the element areas in the first metal layers and; chemically etching off those portions of the semiconductor wafer which are interposed between the active elements with the second metal layers used as masks to separate the thus produced elements from each other, thereby producing a plurality of semiconductor elements, each of which has its surfaces coated with the first and second metal layers.
Claim 5
Dependent Claim
72 words
The method according to claim 1 or 2, wherein the step of selectively forming the second metal layers by electroplating comprises the steps of: forming the first metal layer on the whole surface of each side of the semiconductor wafer; covering the non-element areas in the first metal layers with a plating resist; and crystallizing out the second metal layer each of the exposed areas in the first metal layers by electroplating.
Claim 6
Dependent Claim
89 words
The method according to claim 1 or 2, wherein the step of selectively forming the second metal layers by electroplating comprises the steps of: forming the first metal layer on the whole surface of each side of the semiconductor wafer; crystallizing out the second metal layer on the whole surface of each of the first metal layers by electroplating; covering the element areas in each of the second metal layers with an etching resist; and selectively etching off the second metal layers with said etching resist used as masks.
Claim 7
Dependent Claim
16 words
The method according to claim 1, wherein the second metal layers are formed of Pb-Sn alloy.
Claim 8
Dependent Claim
18 words
The method according to claim 5, wherein the Pb-Sn alloy contains 0.6 to 1.5% by weight of Sn.
Claim 9
Dependent Claim
17 words
The method according to claim 2, wherein the second metal layers are layers of Pb-In/Pb or Pb-Ag/Pb-In/Pb.
Claim 10
Dependent Claim
16 words
The method according to claim 1 or 2, wherein the chemical etching fluid contains hydrofluoric acid.
Claim 11
Dependent Claim
19 words
The method according to claim 1 or 2, wherein the anticorrosive property is defined as resistance to hydrofluoric acid.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-05-16 | 1986-11-15 | 1987-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-16 | 1990-11-15 | 1991-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-16 | 1994-11-15 | 1995-05-17 | $7700.00 | Window Closed / Lapsed |