US4246693A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of fabricating semiconductor device by bonding together silicon substrate and electrode or the like with aluminum
Assignee: Hitachi Ltd
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Filing: 1979-04-20
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Granted: 1981-01-27
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Expires: 1999-04-20
Abstract
Abstract There is provided a method of fabricating a semiconductor device wherein in a bonding surface of a silicon substrate of n-type conductivity are formed recesses having each a bonding surface of a higher order plane index than that of the bonding surface of the silicon substrate, and the substrate and electrodes and the like members are bonded together with an aluminum solder so as to decrease a forward voltage drop FVD. After forming the recesses but prior to the bonding with the aluminum solder, phosphor is diffused into a region ranging from the bonding surface to a depth of 20 microns, thereby further decreasing the forward voltage drop FVD. When cooling after the bonding, a temperature gradient is established so that temperature in the silicon substrate is higher than a temperature in the molten aluminum so that the forward voltage drop FVD can be decreased further.
Inventors
- 👤 Jin Onuki
- 👤 Ko Soeno
- 👤 Masateru Suwa
- 👤 Hisakichi Onodera
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:09
CPC Classifications
H; H10; H10W; H10W99/00; H10P; H10P50/00; Y; Y10; Y10S; Y10S148/00; Y10S148/018; Y10S148/02
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
141 words
In a method of fabricating a semiconductor device wherein a silicon substrate having at least in part an n-type conductivity is bonded to a second silicon substrate or to an electrode with an aluminum solder by heating said silicon substrate, aluminum solder, and second silicon substrate or electrode, whereby a p-type regrowth layer is formed on the n-type conductivity surface of said silicon substrate, thereby increasing the forward voltage drop of the semiconductor device, the process of substantially preventing the increase in the forward voltage drop of said semiconductor device comprising forming in the bonding surface of n-type conductivity of said silicon substrate which is to be bonded to said second silicon substrate or to said electrode, prior to said heating, recesses each of which has a bonding surface of a higher order plane index than that of said bonding surface.
Claim 2
Dependent Claim
141 words
In a method of fabricating a semiconductor device wherein a silicon substrate having at least in part an n-type conductivity is bonded to a second silicon substrate or to an electrode with an aluminum solder by heating said silicon substrate, aluminum solder, and second silicon substrate or electrode, whereby a p-type regrowth layer is formed on the n-type conductivity surface of said silicon substrate, thereby increasing the forward voltage drop of the semiconductor device, the process of substantially preventing the increase in the forward voltage drop of said semiconductor device comprising forming in the bonding surface of n-type conductivity of said silicon substrate which is to be bonded to said second silicon substrate or to said electrode, prior to said heating, recesses each of which has a bonding surface of a higher order plane index than that of said bonding surface.
Claim 3
Independent Claim
109 words
A method of fabricating a semiconductor device comprising the steps of: forming, in a bonding surface of a silicon substrate of n-type conductivity which is to be bonded to an electrode, recesses each of which has a bonding surface of a higher order plane index than that of the bonding surface of said silicon substrate; providing said electrode on the bonding surface of said silicon substrate through an aluminum solder; and integrating said silicon substrate, said aluminum solder and said electrode by heating, whereby increase of the forward voltage drop of said semiconductor device, caused by formation of a p-type conductivity layer in said bonding surface, is substantially prevented.
Claim 4
Independent Claim
109 words
A method of fabricating a semiconductor device comprising the steps of: forming, in a bonding surface of a silicon substrate of n-type conductivity which is to be bonded to an electrode, recesses each of which has a bonding surface of a higher order plane index than that of the bonding surface of said silicon substrate; providing said electrode on the bonding surface of said silicon substrate through an aluminum solder; and integrating said silicon substrate, said aluminum solder and said electrode by heating, whereby increase of the forward voltage drop of said semiconductor device, caused by formation of a p-type conductivity layer in said bonding surface, is substantially prevented.
Claim 5
Dependent Claim
18 words
A method of fabricating a semiconductor device according to claim 2, wherein said recesses are formed by etching.
Claim 6
Dependent Claim
23 words
A method of fabricating a semiconductor device according to claim 3, wherein said etching is effected with an etchant of alkaline aqueous solution.
Claim 7
Dependent Claim
44 words
A method of fabricating a semiconductor device according to claim 2, wherein after forming said recesses, phosphor is diffused into a region ranging from the bonding surface to a depth of 20 microns at a concentration of 3 to 7×10 20 atoms/cm 3 .
Claim 8
Dependent Claim
30 words
A method of fabricating a semiconductor device according to claim 2, wherein after forming said recesses, an acceptor is diffused into said silicon substrate to form a predetermined p-n junction.
Claim 9
Dependent Claim
40 words
A method of fabricating a semiconductor device according to claim 2, wherein when cooling after said heating for said integration, a temperature gradient is established so that temperature in said silicon substrate is higher than a temperature in molten aluminum.
Claim 10
Dependent Claim
29 words
A method of fabricating a semiconductor device according to claim 7, wherein said temperature gradient is established by placing the silicon substrate in contact with a heat insulation member.
Claim 11
Dependent Claim
20 words
A method of fabricating a semiconductor device according to claim 8, wherein said heat insulation member is made of graphite.
Claim 12
Independent Claim
93 words
A method of fabricating a semiconductor device comprising the steps of: forming, in a bonding surface of a silicon substrate of n-type conductivity, recesses each of which has a bonding surface of a higher order plane index than that of the bonding surface of said silicon substrate; and integrating at least two silicon substrates formed with the recesses and an aluminum solder interposed between them by heating, whereby increase of the forward voltage drop of said semiconductor device, caused by formation of a p-type conductivity layer in said bonding surface, is substantially prevented.
Claim 13
Independent Claim
93 words
A method of fabricating a semiconductor device comprising the steps of: forming, in a bonding surface of a silicon substrate of n-type conductivity, recesses each of which has a bonding surface of a higher order plane index than that of the bonding surface of said silicon substrate; and integrating at least two silicon substrates formed with the recesses and an aluminum solder interposed between them by heating, whereby increase of the forward voltage drop of said semiconductor device, caused by formation of a p-type conductivity layer in said bonding surface, is substantially prevented.
Claim 14
Dependent Claim
34 words
A method of fabricating a semiconductor device according to claim 10, wherein at least one of said silicon substrates has one surface in contact with the aluminum solder which is formed with the recesses.
Claim 15
Dependent Claim
18 words
A method of fabricating a semiconductor device according to claim 10, wherein said recesses are formed by etching.
Claim 16
Dependent Claim
23 words
A method of fabricating a semiconductor device according to claim 12, wherein said etching is effected with an etchant of alkaline aqueous solution.
Claim 17
Dependent Claim
30 words
A method of fabricating a semiconductor device according to claim 10, wherein after forming said recesses, an acceptor is diffused into said silicon substrate to form a predetermined p-n junction.
Claim 18
Dependent Claim
24 words
A method of fabricating a semiconductor device according to claim 4 or 13, wherein said alkaline aqueous solution is sodium hydroxide or potassium hydroxide.
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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) | 1984-01-27 | 1984-07-28 | 1985-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-27 | 1988-07-28 | 1989-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-27 | 1992-07-28 | 1993-01-27 | $7700.00 | Window Closed / Lapsed |