Method of controlling etch-pattern density and device made using such method
A method of controlling an etch-pattern density of a polysilicon layer includes depositing polysilicon on a wafer. The method includes determining polysilicon-etch regions that include DMOS source regions within circuit-device areas of the wafer. The method includes calculating an etch area of the p...
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Format: | Patent |
Sprache: | eng |
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Zusammenfassung: | A method of controlling an etch-pattern density of a polysilicon layer includes depositing polysilicon on a wafer. The method includes determining polysilicon-etch regions that include DMOS source regions within circuit-device areas of the wafer. The method includes calculating an etch area of the polysilicon-etch regions and then comparing the calculated etch area of the polysilicon-etch regions to a predetermined minimum etch area. If the calculated etch area is less than a predetermined threshold, the method adds polysilicon-etch regions within non-circuit-device areas to the determined polysilicon-etch regions within the circuit-device areas until the comparing step results in the calculated etch area of the polysilicon-etch regions being greater than the predetermined minimum etch area. The method includes etching the polysilicon from the polysilicon-etch regions in both the circuit-device areas and the non-circuit-device areas. Adding polysilicon-etch regions in non-circuit device areas can advantageously facilitate automatic process control of an etch step. |
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