US5185295A
Expired / Lapsed
US
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Method for dicing semiconductor substrates using a laser scribing and dual etch process
Assignee: Toshiba Corp
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Filing: 1991-05-15
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Granted: 1993-02-09
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Expires: 2011-05-15
Abstract
Abstract The silicon substrate in which mesa semiconductor elements are formed is scribed along dicing lines by a laser. The resolidified silicon, which failed to vaporize during scribing, is etched away by sodium hydroxide solution. As a result, the silicon substrate is separated into a plurality of mesa semiconductor pellets. These pellets undergo chemical etching with a fluoric and nitric acid mixture to smooth the cut surfaces.
Inventors
- 👤 Haruyuki Goto
- 👤 Katsuhiko Kubota
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:29
CPC Classifications
H; H10; H10P; H10P54/00; H10P50/00; H10P50/60; H10P50/64; H10P50/642
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
68 words
A method for dicing semiconductor substrates, comprising the steps of: scribing a silicon substrate containing mesa semiconductor elements by using a laser; separating said silicon substrate into a plurality of pellets by etching away, using alkali hydroxide solution, resolidified silicon that failed to vaporize during laser scribing; and smoothing the cut surfaces of said pellets by chemical etching with a mixed acid containing hydrofluoric acid and nitric acid.
Claim 2
Independent Claim
68 words
A method for dicing semiconductor substrates, comprising the steps of: scribing a silicon substrate containing mesa semiconductor elements by using a laser; separating said silicon substrate into a plurality of pellets by etching away, using alkali hydroxide solution, resolidified silicon that failed to vaporize during laser scribing; and smoothing the cut surfaces of said pellets by chemical etching with a mixed acid containing hydrofluoric acid and nitric acid.
Claim 3
Dependent Claim
26 words
A method according to claim 1, wherein said silicon substrate has p-n junction portions formed therein and said substrate is cut at those p-n junction portions.
Claim 4
Dependent Claim
15 words
A method according to claim 1, wherein said alkali hydroxide solution is sodium hydroxide solution.
Claim 5
Dependent Claim
27 words
A method according to claim 3, wherein said sodium hydroxide solution is in a concentration of 5% and is boiled for 5 to 10 minutes for etching.
Claim 6
Dependent Claim
15 words
A method according to claim 1, wherein said alkali hydroxide solution is potassium hydroxide solution.
Claim 7
Dependent Claim
36 words
A method according to claim 1, wherein said step of smoothing the cut surfaces of said pellets by chemical etching with a mixed acid containing hydrofluoric acid and nitric acid is carried out for several seconds.
Claim 8
Dependent Claim
29 words
A method according to claim 1, wherein said mixed acid containing hydrofluoric acid and nitric acid has a volume ratio of hydrofluoric acid to nitric acid 3 : 2.
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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) | 1996-02-09 | 1996-08-10 | 1997-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-02-09 | 2000-08-10 | 2001-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-02-09 | 2004-08-10 | 2005-02-09 | $7700.00 | Window Closed / Lapsed |