Patent ID: 7153738

Claim:
A method for forming a trench capacitor in a semiconductor device, the trench being formed in a substrate having a surface, the method comprising the steps of: forming the trench in the substrate, the trench having sidewalls and a bottom; forming a first region of a first material in a bottom portion of the trench, the first region having an upper surface below the surface of the substrate, the first material being a first conducting material; subsequently forming a collar structure of dielectric material on a portion of the trench sidewalls above the upper surface of the first region; providing a removable material in the trench overlying the first material and in contact with a lower portion of the collar structure; removing an upper portion of the collar structure; removing the removable material so that the upper surface of the first region is exposed; and forming a second region of a second material overlying the first region and in contact therewith, the second region having an upper surface below the surface of the substrate, wherein the removable material is spin-on glass (SOG).