Patent ID: 8518787

Claim:
A method, comprising: (a) forming a first trench and a second trench in a semiconductor substrate, said first and second trenches extending in a first direction from a top surface of said substrate toward an opposite bottom surface of said substrate a distance less than a thickness of said substrate in said first direction; after (a), (b) simultaneously completely filling said first trench with a dielectric material and forming a liner of said dielectric material on sidewalls of said second trench; after (b), (c) filling remaining space in said second trench with a polysilicon core, recessing said polysilicon core below said top surface of said substrate, and forming, in said second trench, a dielectric plug on said polysilicon core; after (c), (d) removing said dielectric material from said first trench and filling said first trench with and electrically conductive material; and after (d), (e) thinning said substrate from said bottom surface of said substrate to form a new bottom surface of said substrate, said electrically conductive material of said first trench and said liner and polysilicon core of said second trench exposed in said new bottom surface of substrate.