Abstract: To planarize an oxide-filled shallow trench-isolated semiconductor architecture, a composite photoresist sacrificial layer is initially formed on the oxide-filled structure. The composite photoresist layer contains photoresist plugs which are reflowed to fill depressions in the oxide fill layer overlying the trench, and an overlying photoresist layer which effectively planarizes the depression-filled trench oxide layer. Respective photoresist and oxide selective etching chemistries are then successively applied to first etch the composite sacrificial photoresist layer and then etch the trench fill oxide layer down to the surface of an etch stop polysilicon layer.

Abstract: An alignment system and method is provided having an alignment target pattern formed on a semiconductor wafer, with means for scanning that target pattern to produce signals representing dimensions of individual features therein and distances between adjacent features, and with means for interrogating these signals to determine the relative position and distance of the scanned portion of the target pattern from a predetermined reference position. The target pattern includes one or more series of concentric figures, each figure having a particular dimension which differs from the particular dimension of each adjacent figure by a predetermined magnitude and being spaced from adjacent figures by predetermined distances. These predetermined distances and magnitude are detected from the scanning means signals and are used to determine the distance and direction of the scanning position from a reference position.