PERIODIC PATTERN ARRAYS for AUTOMATIC INSPECTION of WAFERS
Original Publication Date: 1988-Sep-01
Included in the Prior Art Database: 2005-Feb-15
Foreign matter (e.g., particulates) and pattern defects are responsible for a major portion of yield degradation in semiconductor manufacturing. Inspection tools are expensive and slow. Such tools cannot inspect logic product because they require periodic patterns as found with memory devices. (Image Omitted) Here repetitive pattern structures permit inspection of logic devices with such a system. For this purpose a fraction of the kerf region will be used (15% to 20% of this area should suffice to perform statistically sound inspection provided an adequate number of such subfields are inspected). A basic design of a suitable periodic array consists of a rectangular array of parallel lines and spaces of equal width shown in Fig. 1A.