Patent ID: 7785983

Claim:
A method for forming a semiconductor device, the method comprising: providing a semiconductor substrate having a first region and a second region, the first region for having one or more first elements and the second region for having one or more second elements, the first elements being different from the second elements; defining a tile location and a first tile surface area for a tile feature on the semiconductor device; forming an active semiconductor layer over both the first region and the second region of the semiconductor substrate; forming a first trench in the active semiconductor layer at the tile location using a negative tone photomask, the first trench having a first depth and forming at least a portion of the tile feature, the first trench enclosing a second tile surface area of the semiconductor device less than or equal to the first tile surface area; forming a second trench in the active semiconductor layer using a positive tone photomask, the second trench having a second depth different than the first depth; forming a third trench at the tile location, the third trench being formed to the second depth at the same time as the second trench with the positive tone photomask, the third trench surrounding the first trench; filling the first and second trenches with a fill material; and chemical mechanical polishing (CMP) the semiconductor device.