US3830665A
Expired / Lapsed
US
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Method for delineating semiconductor junctions
Assignee: Motorola Solutions Inc
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Filing: 1972-12-07
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Granted: 1974-08-20
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Expires: 1992-12-07
Abstract
Abstract A method for etching a groove along a junction between regions of semiconductor material having different dopant concentrations to delineate or isolate the regions forming the junction. Standard concentrations of sirtl etch are used in conjunction with infrared radiation. Wafers in a holder are placed in a container of sirtl etch and exposed to infrared radiation. Preferential etching creates a groove at the semiconductor junction.
Inventors
- 👤 W Roman
- 👤 L Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:07
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/60; H10P50/64; H10P50/642; H10P95/00; Y; Y10; Y10S; Y10S148/00; Y10S148/051; Y10S148/085
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
24 words
The method for etching a groove along a semiconductor junction as recited in claim 1 wherein the semiconductor junction is exposed to infrared radiation.
Claim 2
Dependent Claim
20 words
The method for etching a groove along a semiconductor junction as recited in claim 1 wherein the etching is electroless.
Claim 3
Dependent Claim
34 words
The method for etching a groove along a semiconductor junction as recited in claim 1 wherein said etchant has the characteristic that it preferentially etches high energy areas of the body of semiconductor material.
Claim 4
Dependent Claim
21 words
The method for etching a groove along a semiconductor junction as recited in claim 2 wherein said etchant is sirtl etchant.
Claim 5
Dependent Claim
23 words
The method for etching a groove along a semiconductor junction as recited in claim 1 wherein the semiconductor junction is a PN junction.
Claim 6
Dependent Claim
34 words
The method for etching a groove along a semiconductor junction as recited in claim 1 wherein the semiconductor junction is formed by first and second regions having different concentrations of the same type dopant.
Claim 7
Dependent Claim
28 words
The method for etching a groove along a semiconductor junction as recited in claim 1 wherein the groove is etched sufficiently deep to adequately delineate the semiconductor junction.
Claim 8
Dependent Claim
83 words
The method for etching a groove along a semiconductor junction as recited in claim 4 wherein: said semiconductor junction is formed by silicon semiconductor material; said etchant is a solution of chromium trioxide solution and standard concentrated hydrofluoric acid, the chromium trioxide solution consisting essentially of chromium trioxide solution and deionized water in the ratio of approximately one gram to three mililiters, the ratio of said chromium trioxide solution to standard concentrated hydrofluoric acid being between ten to one and one to one.
Claim 9
Dependent Claim
49 words
The method for etching a groove along a semiconductor junction as recited in claim 4 wherein P-type silicon having a doping concentration in the range from 5 X 1014 atoms per cubic centimeter to 1019 atoms per cubic centimeter is the material on one side of said semiconductor junction.
Claim 10
Dependent Claim
37 words
The method for etching a groove along a semiconductor junction as recited in claim 4 wherein N-type having a doping concentration between 2.5 X 1014 atoms per cubic centimeter and 5 X 1018 atoms per cubic centimeter.
Claim 11
Dependent Claim
29 words
The method for etching a groove along a semiconductor junction as recited in claim 4 when the temperature of the etchant solution is between 25* centigrade and 100* centigrade.
Claim 12
Dependent Claim
34 words
The method for etching a groove along a semiconductor junction as recited in claim 1 wherein the groove is etched sufficiently deep to electrically isolate the regions of semiconductor material forming the semiconductor junction.
Claim 13
Dependent Claim
18 words
The method as recited in claim 1 wherein the body of semiconductor material has the (111) crystal structure.
Claim 14
Dependent Claim
18 words
The method as recited in claim 1 wherein the body of semiconductor material has the (100) crystal structure.
Claim 15
Dependent Claim
22 words
The method for etching a groove along a semiconductor junction as recited in claim 1 wherein said etchant is a gaseous etchant.
Claim 16
Independent Claim
74 words
A method for delineating a semiconductor junction in a semiconductor wafer by electrolessly etching a groove along the semiconductor junction comprising the steps of: providing a infrared lamp positioned directly over a container of sirtl etchant, said infrared lamp emitting infrared light into said sirtl etchant, and placing the semiconductor wafer in a wafer holder; submerging said wafer holder in said etChant so that the semiconductor wafer is completely submerged for a specified time.
Claim 17
Dependent Claim
16 words
The method as recited in claim 13 wherein said specified time is less than 30 seconds.
Claim 18
Dependent Claim
19 words
The method as recited in claim 13 wherein said wafer is removed from said sirtl etchant, rinsed and dried.
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) | 1977-08-19 | 1978-02-18 | 1978-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-19 | 1982-02-18 | 1982-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-19 | 1986-02-18 | 1986-08-20 | $7700.00 | Window Closed / Lapsed |