TEST WAFER AND USING METHOD THEREFOR

摘要

Disclosed herein is a using method for a test wafer including a test substrate and a metal foil formed on the front side of the test substrate. The using method includes a modified layer forming step of applying a laser beam having a transmission wavelength to the test substrate from the back side of the test wafer in the condition where the focal point of the laser beam is set inside the test substrate, thereby forming a modified layer inside the test substrate, and a damage detecting step of observing the front side of the test wafer after performing the modified layer forming step, thereby detecting damage to the metal foil.

主权项

1. A test wafer for use in examining the effect of leaky light of a laser beam in performing laser processing to an actual wafer including a substrate and a plurality of devices formed on a front side of said substrate so as to be separated by a plurality of crossing division lines, said laser beam having a transmission wavelength to said substrate being applied to said actual wafer from a back side thereof along each division line to thereby form a modified layer inside said substrate along each division line, said test wafer comprising:
a test substrate; and a metal foil formed on a front side of said test substrate.