Wafer method for breaking a semiconductor

• US 5,527,744 A
• Filed: 11/21/1994
• Issued: 06/18/1996
• Est. Priority Date: 01/07/1993
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Mignardi, Michael A., Alfaro, Rafael C.
• Primary Examiner(s): Thomas, Tom
• Assistant Examiner(s): TRINH, MICHAEL MANH
• Application Number:
  US08/342,988
• Time in Patent Office: 575 Days
• Field of Search: 437/226, 437/227, 437/209, 437/212, 148/DIG. 28
• US Class Current: 216/2
• CPC Class Codes: B28D 5/0011 with preliminary treatment, e.g. weakening by scoring
• CPC Class Codes: B28D 5/0023 rectilinearly
• CPC Class Codes: B28D 5/0047 using fluid or gas pressure
• CPC Class Codes: B81C 1/00896 Temporary protection during separation into individual elements
• CPC Class Codes: H01L 21/304 Mechanical treatment, e.g. grinding, polishing, cutting H01L21/30625 takes precedence
• CPC Class Codes: H01L 21/3043 Making grooves, e.g. cutting
• 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
• CPC Class Codes: Y10T 156/1064 Partial cutting [e.g., grooving or incising]
• CPC Class Codes: Y10T 225/12 With preliminary weakening

Abstract

A process for partially sawing the streets on semiconductor wafers. After sawing the streets can be covered by a protective material, and then the wafer continues its processing as before. After the wafer is broken, the protective material may or may not be removed. Additionally, the wafer may be broken into individual chips using a wedge piece that has a number of individual wedges on it, where the individual wedges press against the partially sawn streets, causing the wafer to break.

Claims

1. A method for processing and handling semiconductor wafers comprising the steps of:

a. partially sawing streets in a wafer upon which are partially processed micromechanical devices including structures supported above said wafer by a sacrificial layer;

b. covering said streets with a protective coating such that said protective coating does not interfere with said micromechanical devices or said sacrificial layer;

c. processing said wafer such that said sacrificial layer is removed thereby allowing said micromechanical devices to move freely and exposing surfaces underneath said micromechanical devices;

d. positioning a wedge piece with a plurality of wedges adjacent said wafer such that said wedges are aligned along said partially sawn streets without any of said wedges being in contact with said wafer;

e. applying pressure to force said wafer against said wedges causing said wafer to break into chips along said partially sawn streets, wherein said protective coating prevents any debris from said breaking from coming into contact with any of said surfaces underneath said micromechanical devices; and

f. removing said chips.

2. The process of claim 1 wherein said protective coating is tape.

3. The process of claim 1 wherein said protective coating is caulking.

4. The process of claim 1 further comprises the step of removing the protective material.

5. The process of claim 1 wherein said sawing step includes mounting said wafer to a saw frame, and said wafer remains on said saw frame throughout said sawing, covering, processing, positioning, applying and removing steps.

6. The process of claim 1 wherein said sawing step includes mounting said wafer to a saw frame, and then demounting said water from said saw frame after said sawing step is completed.

7. The process of claim 1 wherein said applying pressure further comprises applying a vacuum to force said wafer against said wedge piece.

8. The process of claim 1 wherein said applying pressure further comprises using a mechanical arm to push said wafer against said wedge piece.