Wafer processing method

Patent metadata

Field	Value
Publication number	US-10790192-B2
Application number	US-201916375010-A
Country	US
Kind code	B2
Filing date	Apr 4, 2019
Priority date	Apr 9, 2018
Publication date	Sep 29, 2020
Grant date	Sep 29, 2020

Abstract

A method for processing a wafer in which patterns including a metal layer are formed on streets. The method includes: a step of applying a laser beam along the streets formed with the patterns to form laser processed grooves while removing the patterns; a step of forming cut grooves having a depth in excess of a finished thickness of the wafer, inside the laser processed grooves; a step of grinding the back surface side of the wafer to thin the wafer to the finished thickness and to expose the cut grooves to the back surface of the wafer, thereby dividing the wafer into a plurality of device chips; a step of removing a crushed layer formed on the back surface side of the wafer; and a step of forming a strain layer on the back surface side of the wafer by plasma processing using an inert gas.

First claim

What is claimed is:

1. A method for processing a wafer in which devices are formed respectively in regions on a front surface side partitioned by a plurality of streets and in which patterns including a metal layer are formed on the streets, the method comprising:
a laser processing step of applying a laser beam of such a wavelength as to be absorbed in the wafer along the streets formed with the patterns, to form laser processed grooves while removing the patterns;
a cut groove forming step of forming cut grooves having a depth in excess of a finished thickness of the wafer, inside the laser processed grooves, by a cutting blade thinner than a width of the laser processed grooves;
a protective member adhering step of adhering a protective member to the front surface side of the wafer formed with the cut grooves;
a grinding step of holding the wafer by a chuck table through the protective member, grinding a back surface side of the wafer to thin the wafer to the finished thickness, and to expose the cut grooves to the back surface of the wafer, thereby dividing the wafer into a plurality of device chips;
a crushed layer removing step of removing a crushed layer formed on the back surface side of the wafer by the grinding of the wafer; and
a strain layer forming step of forming a strain layer on the back surface side of the wafer deprived of the crushed layer, by plasma processing using an inert gas.

2. The method for processing a wafer according to claim 1 , wherein in the crushed layer removing step, the crushed layer is removed by polishing with a polishing pad.

3. The method for processing a wafer according to claim 1 , wherein in the crushed layer removing step, the crushed layer is removed by plasma etching using a halogen-containing gas.

4. The method for processing a wafer according to claim 1 , further comprising:
a protective film forming step of forming a water-soluble protective film on the front surface side of the wafer before the laser processing step, and a protective film removing step of removing the protective film from the front surface side of the wafer after the laser processing step.

Assignees

• Disco Corp

Inventors

• Nishida Yoshiteru
• Iida Hidekazu
• Yokoo Susumu
• Takahashi Hiroyuki
• Chito Kenta

Classifications

• H10P90/123

  by grinding or lapping · CPC title

• H10P72/0428 Primary

  Apparatus for mechanical treatment or grinding or cutting · CPC title

• H10P72/78

  using vacuum or suction, e.g. Bernoulli chucks · CPC title

• H10P52/00

  Grinding, lapping or polishing of wafers, substrates or parts of devices · CPC title

• H10P54/00 Primary

  Cutting or separating of wafers, substrates or parts of devices · CPC title