Power MOSFET with metal filled deep sinker contact for CSP

A method of forming an integrated circuit (IC) including a power semiconductor device, comprising:

• providing a substrate having an epitaxial (epi) layer thereon with at least one transistor formed within said epi layer and being covered by a pre-metal dielectric (PMD) layer;
• etching contact openings through said PMD layer and at least a portion of said epi layer, said contact openings including a sinker trench which extends to at least a first node of said power semiconductor device;
• depositing a metal fill material, wherein said metal fill material covers a sidewall and a bottom of said sinker trench but does not completely fill said sinker trench;
• depositing a dielectric filler layer over said metal fill material to fill said sinker trench;
• removing an overburden region of said dielectric filler layer stopping on a surface of said metal fill material in said overburden region to form a sinker contact, wherein a portion of said dielectric filler layer remains in said sinker trench after said removing of said overburden region of said dielectric filler layer;
• and
• forming a patterned interconnect metal to provide a connection between said interconnect metal and said metal fill material on said sidewall of said sinker trench.