Wafer scribe technique using laser by forming polysilicon

• US 5,543,365 A
• Filed: 12/02/1994
• Issued: 08/06/1996
• Est. Priority Date: 12/02/1994
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Wills, Kendall S., Brewer, Melvin, Rodriguez, Paul A.
• Primary Examiner(s): Breneman, R. Bruce
• Assistant Examiner(s): Paladugu, Ramamohan Rao
• Application Number:
  US08/347,988
• Time in Patent Office: 613 Days
• Field of Search: 437/226, 437/227, 148/DIG. 28
• US Class Current: 438/462
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/146 the fluid stream containing a liquid
• CPC Class Codes: B23K 26/364 for making a groove or trench, e.g. for scribing a break initiation groove
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• 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
• CPC Class Codes: Y10S 148/028 Dicing

Abstract

A channel is formed in a wafer to fore descrite die. A portion of the wafer is heated in the channel. A portion of the heated portion is cooled to eliminate the uniform structure. The cooled portion is scribed to separate the die.

Claims

1. A method for preventing cracks as a result of a scribing operation, comprising the steps of:

forming a channel in a wafer to provide descrite die;

heating a first portion of said wafer under the channel

cooling a second portion of said first portion to form a polysilicon structure that eliminates the uniform structures of said wafer of silicon within the second portion;

scribing said second portion in order to separate said die.

2. A method for preventing cracks as in claim 1, wherein said cooling step includes the step of cooling with water.

3. A method for preventing cracks as in claim 1, wherein said heating step includes the step of heating with a laser.

4. A method for preventing cracks as in claim 1, wherein said forming step includes the step of forming said channel by etching.

5. A method for preventing cracks as a result of a scribing operation, comprising the steps of:

forming a channel in a wafer to provide descrite die;

heating a first portion of said wafer under the channel;

heating a second portion of said wafer under the channel;

cooling a third portion and fourth portion of said wafer of said first and second portion respectively to form a polysilicon structure within the first and second portion structure that eliminates the uniform structure of the wafer of silicon.

6. A method for preventing cracks as in claim 5, wherein said cooling step includes the step of cooling said third portion and said fourth portion with water.

7. A method for preventing cracks as in claim 5, wherein said heating step includes the step of heating with a laser.

8. A method for preventing cracks as in claim 5, where said forming step includes the step of forming said channel by etching.

9. A method for preventing cracks as a result of a descrite operation, comprising the steps of:

forming a channel in a wafer to provide descrite die;

heating a first portion of said wafer under the channel on a first side of said wafer;

heating a second portion of said wafer on a second side of said wafer; and

cooling a third portion of said second portion to form a polysilicon structure eliminates the uniform structure of said wafer of silicon within the third portion scribing said third portion in order to separate said die.

10. A method for preventing cracks as in claim 9, wherein said cooling step includes the step of cooling with water.

11. A method for preventing cracks as in claim 9, wherein said heating step includes the step of heating with a laser.

12. A method for preventing cracks as in claim 9, wherein said forming step includes the step of forming said channel by etching.