Wafer processing method

Patent metadata

Field	Value
Publication number	US-9583391-B2
Application number	US-201615202142-A
Country	US
Kind code	B2
Filing date	Jul 5, 2016
Priority date	Jul 6, 2015
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

There is provided a wafer processing method including a modified layer forming step. In the wafer processing method, the power of a pulse laser beam set in the modified layer forming step is set to a power that forms modified layers and cracks in such a manner that a wafer is allowed to be divided into individual device chips before the thickness of the wafer reaches a finished thickness and, after the wafer is divided into the individual device chips, the time until the thickness of the wafer reaches the finished thickness is such a time that damage due to rubbing of the individual device chips against each other is not caused through grinding under a predetermined grinding condition set in a back surface grinding step.

First claim

What is claimed is:

1. A wafer processing method for dividing a wafer on which a plurality of devices are formed on a front surface and are marked out by planned dividing lines into individual device chips, the wafer processing method comprising:
a protective member disposing step of disposing a protective member on the front surface of the wafer;
a modified layer forming step of positioning a light focus point of a pulse laser beam having such a wavelength as to be transmitted through the wafer on which the protective member is disposed at inside of the wafer along the planned dividing lines and irradiating the wafer with the pulse laser beam with predetermined power to form modified layers and cracks extending from the modified layers toward the front surface and a back surface; and
a back surface grinding step of, after carrying out the modified layer forming step, holding a side of the protective member on a chuck table and grinding the back surface of the wafer by a grinding wheel under a predetermined grinding condition to divide the wafer into the individual device chips and carrying out grinding until the modified layers are removed and thickness of the wafer reaches a target finished thickness,
wherein the predetermined power of the pulse laser beam set in the modified layer forming step is set to a power that forms the modified layers and the cracks in such a manner that the wafer is allowed to be divided into the individual device chips before the thickness of the wafer reaches the target finished thickness and, after the wafer is divided into the individual device chips, a time until the thickness of the wafer reaches the target finished thickness is such a time that damage due to rubbing of the individual device chips against each other is not caused through grinding under the predetermined grinding condition set in the back surface grinding step.

Assignees

• Disco Corp

Inventors

• Nakamura Masaru

Classifications

• H10P54/00 Primary

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

• H10P58/00 Primary

  Singulating wafers or substrates into multiple chips, i.e. dicing · CPC title

• B23K26/53

  for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks · CPC title

• B23K26/0006

  taking account of the properties of the material involved (B23K26/32, B23K26/40 take precedence) · CPC title

• B23K2103/56

  being semiconducting · CPC title