Patent ID: 8637340
Filing Date: 2014-01-28
Classification: B23K,H01L,Y02E,Y02P

Abstract:
1. A method of ablating an electrically insulating layer on a semiconductor substrate, said method comprising: providing a semiconductor substrate having n-type doping; depositing a first relatively thin layer of undoped glass or undoped oxide on a surface of said semiconductor substrate; depositing a first relatively thin semiconductor layer comprising a substance chosen from the group consisting of amorphous semiconductor, nanocrystalline semiconductor, microcrystalline semiconductor, and polycrystalline semiconductor on said relatively thin layer of undoped glass or undoped oxide; depositing a layer of borosilicate glass or a borosilicate/undoped glass stack on said relatively thin semiconductor layer; selectively ablating said layer of borosilicate glass or borosilicate/undoped glass stack with a pulsed laser, said relatively thin semiconductor layer substantially protecting said semiconductor substrate from said pulsed laser; depositing a second relatively thin layer of undoped glass or undoped oxide on said surface of said semiconductor substrate; depositing a second relatively thin semiconductor layer comprising a substance chosen from the group consisting of amorphous semiconductor, nanocrystalline semiconductor, microcrystalline semiconductor, and polycrystalline semiconductor on said relatively thin layer of undoped glass or undoped oxide; depositing a layer of undoped glass or undoped oxide on said second relatively thin semiconductor layer; and selectively ablating said layer of undoped glass or undoped oxide with a pulsed laser, said second relatively thin semiconductor layer substantially protecting said semiconductor substrate from said pulsed laser.