Method for dicing semiconductor substrates using a laser scribing and dual etch process

• US 5,185,295 A
• Filed: 05/15/1991
• Issued: 02/09/1993
• Est. Priority Date: 05/16/1990
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Kubota, Katsuhiko, Goto, Haruyuki
• Primary Examiner(s): Chaudhuri, Olik
• Assistant Examiner(s): HORTON, KENNETH
• Application Number:
  US07/700,413
• Time in Patent Office: 636 Days
• Field of Search: 437/226, 437/227, 148/DIG. 28, 156/628, 156/651, 156/652, 156/653
• US Class Current: 438/463
• CPC Class Codes: H01L 21/30604 Chemical etching
• CPC Class Codes: H01L 21/78 with subsequent division of the substrate into plural individual devices cutting to change the surface-physical characteristics or shape of semiconductor bodies H01L21/304

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.

Claims

1. 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.

2. 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.

3. A method according to claim 1, wherein said alkali hydroxide solution is sodium hydroxide solution.

4. 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.

5. A method according to claim 1, wherein said alkali hydroxide solution is potassium hydroxide solution.

6. 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.

7. 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.