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 detect and size particles over a range of values, on the surface of bare silicon wafers. Use this particle size analyzer to characterize particles common to your process. Leopard Contamination Standard Product Description Utilizing spot depositions, VLSI Standards' particle size analyzer 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 and analyze particle size, and not particle count. Background contamination is kept at an extremely low level and is described on the measurement certificate. Leopard Contamination Standard 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 Traceable to SI Units through NIST * Sizes in other ranges may be available. Please check with VLSI Standards.