US3891483A
Expired / Lapsed
US
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Method for etching semiconductor surfaces
Assignee: Licentia Patent Verwaltungs GmbH
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Filing: 1974-05-30
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Granted: 1975-06-24
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Expires: 1994-05-30
Abstract
Abstract A method for etching semiconductor surfaces of a semiconductor body includes the step of soldering coated electrodes to the semiconductor body to provide exposed semiconductor surfaces and protected semiconductor surfaces covered by the coated electrodes. Each coated electrode comprises an electrode to which a nickel layer and then a silver layer has been applied. The semiconductor body is contacted with an etchant to etch the exposed semiconductor surfaces. The etched body is rinsed with deionized water and then treated with an ammoniacal hydrogen peroxide solution.
Inventors
- 👤 Jurgen Messerschmidt
- 👤 Rigobert Schimmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:35
CPC Classifications
H; H10; H10P; H10P70/00; H10P70/10; H10P70/15; H10P50/00; H10P50/60; H10P50/64; H10P50/642; H10P50/644; H10P50/69; H10P50/691; H10P50/692; H10P95/00
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
90 words
A METHOD FOR ETHCING SEMICONDUCTOR SURFACES OF A SEMICONDUCTOR BODY COMPRISING: A. SOLDERING COATED ELECTRODES TO THE SEMICONDUCTOR BODY, SAID COATED ELECTRODES EACH COMPRISING AN ELECTRODE TO WHICH A NICKEL LAYER AND THEN A LAYER OF SILVER HAS BEEN APPLIED, TO PROVIDE EXPOSED SEMICONDUCTOR SURFACES AND PROTECTED SEMI-CONDUCTOR SURFACES COVERED BY SAID COATED ELECTRODES, B. CONTACTING THE SEMICONDUCTOR BODY WITH AN ETCHANT TO ETCH THE EXPOSED SEMICONDUCTOR SURFACES, C. RINSING THE ETCHED SEMICONDUCTOR BODY SURFACES WITH DEIONIZED WATER, AND D. TREATING THE RINSED BODY WITH AN AMMONIACAL HYDROGEN PEROXIDE SOLUTION.
Claim 2
Independent Claim
90 words
A METHOD FOR ETHCING SEMICONDUCTOR SURFACES OF A SEMICONDUCTOR BODY COMPRISING: A. SOLDERING COATED ELECTRODES TO THE SEMICONDUCTOR BODY, SAID COATED ELECTRODES EACH COMPRISING AN ELECTRODE TO WHICH A NICKEL LAYER AND THEN A LAYER OF SILVER HAS BEEN APPLIED, TO PROVIDE EXPOSED SEMICONDUCTOR SURFACES AND PROTECTED SEMI-CONDUCTOR SURFACES COVERED BY SAID COATED ELECTRODES, B. CONTACTING THE SEMICONDUCTOR BODY WITH AN ETCHANT TO ETCH THE EXPOSED SEMICONDUCTOR SURFACES, C. RINSING THE ETCHED SEMICONDUCTOR BODY SURFACES WITH DEIONIZED WATER, AND D. TREATING THE RINSED BODY WITH AN AMMONIACAL HYDROGEN PEROXIDE SOLUTION.
Claim 3
Dependent Claim
20 words
The method as defined in claim 1 wherein the semiconductor surfaces are etched with a nitric acid/hydrofluoric acid/acetic acid mixture.
Claim 4
Dependent Claim
28 words
The method as defined in claim 1 wherein the electrodes are completely covered with the nickel layer and silver layer before they are soldered to the semiconductor body.
Claim 5
Dependent Claim
45 words
The method as defined in claim 1 wherein before soldering the electrodes have been coated with a nickel layer and then a silver layer on those surface portions which form the free surface of the electrodes after application of the electrodes to the semiconductor body.
Claim 6
Dependent Claim
13 words
The method as defined in claim 1 wherein the electrodes are copper electrodes.
Claim 7
Dependent Claim
29 words
The method as defined in claim 5 wherein the copper electrodes are soldered on via intermediate layers of aluminum, tungsten or molybdenum to opposing surfaces of the semiconductor body.
Claim 8
Dependent Claim
19 words
The method as defined in claim 1 wherein the semiconductor wafer which is being etched is made of silicon.
Claim 9
Dependent Claim
20 words
The method as defined in claim 1 wherein the semiconductor body comprises a column of a plurality of silicon wafers.
Claim 10
Dependent Claim
27 words
The method as defined in claim 8 wherein the silicon wafers in the column are connected to one another by alloying with aluminum or aluminum containing alloys.
Claim 11
Dependent Claim
22 words
The method as defined in claim 8 wherein the electrodes are soldered to the silicon wafers by aluminum or aluminum containing alloys.
Claim 12
Dependent Claim
61 words
The method as defined in claim 9 wherein the aluminum layers present between the silicon wafers are not attacked by the etching medium and thus protrude over the edges of the silicon wafers after the etching process and removal of the outer silicon layers, are simultaneously and in the same process step dissolved and removed in the ammoniacal hydrogen peroxide mixture.
Claim 13
Dependent Claim
17 words
The method as defined in claim 1 wherein the nickel layer is applied to the electrodes electrolytically.
Claim 14
Dependent Claim
27 words
The method as defined in claim 1 wherein the nickel layer is deposited on the electrodes to a thickness of 4 + or - 1 Mu .
Claim 15
Dependent Claim
21 words
The method as defined in claim 1 wherein the silver layer is electrolytically applied to the nickel layer of the electrodes.
Claim 16
Dependent Claim
28 words
The method as defined in claim 1 wherein the silver layer is deposited onto the nickel layer to a thickness of 4 + or - 1 Mu .
Claim 17
Dependent Claim
43 words
The method as defined in claim 1 wherein the etching is effected with an acid mixture containing 2 parts by volume fuming nitric acid, 1 part by volume of a 40% hydrofluoric acid solution and 1 part by volume of concentrated acetic acid.
Claim 18
Dependent Claim
20 words
The method as defined in claim 1 wherein the etching is effected at a temperature of about 18* to 20*C.
Claim 19
Dependent Claim
18 words
The method as defined in claim 1 wherein the etching is effected for about 15 to 300 seconds.
Claim 20
Dependent Claim
27 words
The method as defined in claim 1 wherein the treatment with the ammoniacal hydrogen peroxide solution treatment is begun at a temperature of about 55* to 60*C.
Claim 21
Dependent Claim
49 words
The method as defined in claim 1 wherein the treatment with the ammoniacal hydrogen peroxide solution is effected with a mixture of 1 part by volume concentrated ammonium hydroxide solution, 1 part by volume of a 30% hydrogen peroxide solution and 4 parts by volume of completely deionized water.
Claim 22
Dependent Claim
28 words
The method as defined in claim 1 wherein the treatment with the ammoniacal hydrogen peroxide solution is carried out for a period of about 4 to 5 minutes.
Claim 23
Dependent Claim
33 words
The method of claim 6 wherein a first electrode is soldered to the top surface of the semiconductor body and a second electrode is soldered to the bottom surface of the semiconductor body.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-23 | 1978-12-23 | 1979-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-23 | 1982-12-23 | 1983-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-23 | 1986-12-23 | 1987-06-24 | $7700.00 | Window Closed / Lapsed |