Patent ID: 8563381
Filing Date: 2013-10-22
Classification: H01L

Abstract:
1. A method for manufacturing a power semiconductor device comprising the steps of: forming a trench mask over top surface of an epitaxial layer, the trench mask having apertures defining location of a plurality of gate trenches; etching through the apertures in the trench mask to form a plurality of gate trenches in the epitaxial layer; removing the trench mask; forming a first insulation layer on inner surface of said gate trenches; depositing a gate conductive layer over said first insulation in said gate trenches and onto top surface of said epitaxial layer; etching or CMP said gate conductive layer such that said gate conductive layer is removed away from the top surface of said epitaxial layer; carrying out ion implantation with dopant type opposite to said epitaxial layer to form a plurality of first doped regions extending between every two adjacent of said gate trenches; forming implantation mask over the top surface of said epitaxial layer, wherein the implantation mask has apertures defining location of a plurality of second doped regions in active area; carrying out ion implantation with dopant type same as said epitaxial layer such that said second doped regions are formed near top surface of said first doped regions; depositing a second insulation layer over the top surface of said epitaxial layer; forming a contact mask over said second insulation layer, the contact mask having apertures defining location of a plurality of first-second-doped regions contact trenches; etching said second insulation layer and said epitaxial layer through the apertures in said contact mask such that the first-second-doped-regions contact trenches have sidewalls in said second doped regions with taper angle α carrying out ion implantation with dopant type opposite to said epitaxial layer to form a third doped region surrounding at least bottom of each of said first-second-doped regions contact trenches within said first doped regions; carrying out at least one ion implantation with dopant type opposite to said epitaxial layer to form at least a fourth doped region underneath said third doped region.