Technique for Reference Based Inspection of IC Chips With Isolation Trenches
Original Publication Date: 1988-Dec-01
Included in the Prior Art Database: 2005-Feb-16
The following method permits integrated circuit chips on patterned wafers to be inspected for pattern defects and particulates without excessively high false alarms resulting from isolation trenches in the chip. The false alarms result from the granular structure of the polysilicon material used to fill the trenches, which material produces optical differences that are detected as defects by the self-reference techniques used in the automatic inspection of chips. More particularly, the size of the granular structure is on the same order of magnitude as the minimum defect size to be detected, resulting in the trench material being incorrectly detected as defects. A method is described which suppresses defect detection in the trenches.