Patent ID: 8372717

Claim:
A Method for manufacturing a super-junction trench MOSFET with resurf stepped oxide comprising the steps of: growing an epitaxial layer of a first conductivity type upon a heavily doped substrate of said first conductivity type; forming a block layer on a top surface of said epitaxial layer; forming a trench mask on said block layer; forming a plurality of trenches, and mesas between adjacent trenches in said epitaxial layer by etching through open regions in said block layer; keeping said block layer substantially covering said mesas and a termination area after formation of said trenches to block sequential angle ion implantation into top surfaces of said mesas and said termination area; carrying out an angle ion implantation of a second conductivity type dopant into said mesas through said open regions in said block layer to form a first doped column regions between said adjacent trenches; carrying out an angle ion implantation of said first conductivity type dopant into said mesas through said open regions in said block layer to form a second doped column regions adjacent to sidewalls of said trenches and in parallel surrounding said first doped column regions; removing said block layer after formation of said first and second doped column regions; forming a first insulation layer along inner surface of said trenches; depositing a first doped poly-silicon filling said trenches serving as source electrodes; etching back said source electrodes and said first insulation layer from upper portion of said trenches and from the top surface of said epitaxial layer; forming a second insulation layer as a gate oxide layer along upper sidewalls of said trenches and onto top surfaces of said source electrodes, wherein said second insulation layer has a thinner thickness than said first insulation layer; depositing a second doped poly-silicon filling the upper portion of said trenches to serve as gate electrodes; etching back said gate electrodes by CMP or plasma etch from top surface of said mesas; applying a body mask onto the top surface of said epitaxial layer; carrying out a body implantation of said second conductivity type dopant and a body diffusion to form body regions; removing said body mask and applying a source mask onto the top surface of said epitaxial layer; carrying out a source implantation of said first conductivity type dopant and a source diffusion to form source regions, forming a contact interlayer covering entire top surface; forming a plurality of trenched source-body contacts penetrating through said contact interlayer, said source regions and extending into said body regions; and forming body contact doped regions of said second conductivity type in said body regions and surrounding at least bottoms of said trenched source-body contacts, said body contact doped regions having a heavier doping concentration than said body regions.