Patent ID: 9305793
Filing Date: 2016-04-05
CPC Classification: H01L

Claim Text:
1. A wafer processing method for forming a via hole in a wafer having a first side and a second side opposite to the first side, comprising: a filament forming step of applying a pulsed laser beam to said wafer from the second side thereof, said pulsed laser beam having a transmission wavelength to said wafer, in a condition where the focal point of said pulsed laser beam is set inside said wafer in a subject area where said via hole is to be formed, thereby forming an amorphous filament inside said wafer in said subject area, said amorphous filament including a central fine hole extending from the second side to the first side of said wafer and an amorphous layer surrounding the central fine hole; and an etching step of etching said amorphous filament formed inside said wafer by using an etching agent to thereby form said via hole inside said wafer.