The map of a wafer which was deposited with PSL spheres of various sizes.   SPOT PROBLEMS QUICKLY. The Leopard Contamination Standard (LCS) is used to calibrate instruments which size and detect particles over a range of values, on the surface of bare silicon wafers. Use it to characterize particles common to your process. Product Description Utilizing spot depositions, VLSI Standards places distinct groups of polystyrene latex (PSL) spheres onto the surface of bare silicon wafers. Standards are made containing a choice of 4, 5 or 6 homogenous spots, and are offered in incremental range from 0.050 µm to 3 µm. Each spot is approximately 20 mm in diameter and contains approximately 5,000 spheres. The Leopard Contamination Standard is designed to calibrate particle size, and not particle count. Background contamination is kept at an extremely low level and is described on the measurement certificate. Product Specifications SEMI Specification Silicon Wafers 200 mm and 300 mm diameter silicon wafers Spots 4, 5 or 6 Polystyrene Latex Spheres From 50 nm up to 3 micron* Traceability PSL diameter traceable to NIST * Sizes in other ranges may be available. Please check with VLSI Standards.