Wafer processing method

Patent metadata

Field	Value
Publication number	US-9379015-B2
Application number	US-201314069705-A
Country	US
Kind code	B2
Filing date	Nov 1, 2013
Priority date	Nov 22, 2012
Publication date	Jun 28, 2016
Grant date	Jun 28, 2016

Abstract

A wafer processing method divides a wafer into individual devices along crossing streets formed on the front side of the wafer. The wafer has a substrate and a functional layer formed on the front side of the substrate. The individual devices are formed from the functional layer and are partitioned by the streets. A laser beam is applied along the streets from the front side of the functional layer to thereby remove the functional layer along the streets. A resist film is formed on the front side of the functional layer except on each street. The substrate of the wafer is plasma-etched along each street where the functional layer is absent to the depth corresponding to the finished thickness of each device, thereby forming a division groove along each street and also etching off a modified layer formed on the opposite sides of each street.

First claim

What is claimed is:

1. A wafer processing method for dividing a wafer into a plurality of individual devices along a plurality of crossing streets formed on a front side of said wafer, said wafer being composed of a substrate and a functional layer formed on a front side of said substrate, said individual devices being formed from said functional layer and partitioned by said streets, said wafer processing method comprising:
a protective film forming step of applying a liquid resin to a front side of said functional layer of said wafer to thereby form a protective film;
a functional layer removing step of applying a laser beam along said streets formed on said wafer from the front side of said functional layer of said wafer to thereby remove said functional layer along said streets, wherein said functional layer removing step is performed after said protective film forming step;
a resist film forming step of forming a resist film on the front side of said functional layer of said wafer in an area except each street after performing said functional layer removing step;
a plasma etching step of plasma-etching said substrate of said wafer along each street where said functional layer is absent to the depth corresponding to the finished thickness of each device after performing said resist film forming step, thereby forming a division groove along each street and also etching off a modified layer formed on the opposite sides of each street in said functional layer removing step;
a protective member attaching step of attaching a protective member to the front side of said functional layer of said wafer after performing said plasma etching step; and
a back grinding step of grinding a back side of said substrate to reduce the thickness of said substrate to the finished thickness of each device after performing said protective member attaching step, thereby exposing each division groove to the back side of said substrate and accordingly dividing said wafer into said individual devices.

2. The wafer processing method according to claim 1 , wherein said plasma etching step includes a modified layer removing step of removing said modified layer formed on the opposite sides of each street by using SF6 and a division groove forming step of forming said division groove along each street by alternately using SF6 and C4F8.

3. The wafer processing method according to claim 1 , comprising:
a wafer supporting step of attaching the back side of said substrate of said wafer to an adhesive tape supported to an annular frame and peeling off said protective member attached to the front side of said functional layer of said wafer after performing said back grinding step.

Assignees

• Disco Corp

Inventors

• Matsuzaki Sakae
• Arami Junichi

Classifications

• H10P54/00 Primary

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

• B23K2103/172

  wherein at least one of the layers is non-metallic · CPC title

• B23K26/364

  for making a groove or trench, e.g. for scribing a break initiation groove · CPC title

• B23K26/40

  taking account of the properties of the material involved · CPC title

• B23K2101/40

  Semiconductor devices · CPC title