Patent ID: 6359276
Filing Date: 2002-03-19
Classification: G01J,H01L

Abstract:
A method for forming a microbolometer infrared sensor comprising:providing a silicon substrate having a CMOS circuit, an additional p-well and two electrical conductors extending from said CMOS circuit to the edge of said p-well region; removing the passivation film over the surface of said p-well region; forming a first anodization mask to expose a central portion of the surface of said p-well region; performing a first anodization of said substrate in HF solution to convert the upper layer of said p-well region into a first porous silicon layer; forming a thin film protecting the surface of the inner pores of said first porous silicon layer from etching by a diluted base solution; forming a first insulating film coating the surface of said first porous silicon layer; forming a thermal sensitive resistor disposed on the surface of said first insulating film and having end portions being in contact with said electrical conductor; forming a second insulating film coating said thermal sensitive resistor; forming an infrared absorber covering the top of said first porous silicon layer; forming a second anodization mask having trenches disposed along the edge of said p-well region and depressing into said p-well region; performing a second anodization of said substrate in HF solution to convert the lower layer of said p-well region into a second porous silicon layer; forming more trenches passing through said first porous silicon layer; removing the second porous silicon layer; and removing the remaining anodization mask film.