Method for improving planarity of shallow trench isolation using multiple simultaneous tiling systems
In a feature layer of a semiconductor wafer, dummy tiles which overcome the tendency of dishing and erosion to occur during a CMP process are placed with various sizes and in various positions. An isolation zone is provided around active features. A scanning process of the feature layout surveys oxide density and nitride density over the wafer layer outside of said isolation zone. Values of the ratios of oxide/nitride density for two or more length scales which define tiling zones, are calculated. Tile placement and sizing in the zones is dependent upon the oxide/nitride density ratio values; and further upon an oxide deposition model specific to the oxide used in the fabrication process and upon a polishing model of the CMP process being employed.
AMD, Inc. Motorola, Inc.
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inventional inventional
Ruiqi Edward Outlaw Thomas Michael
Tian Travis, Jr. Brown