Contamination Products
Edge Contamination Standards

PSL wafer for particle size standards
The Edge Contamination Standard appears to the naked eye as a bare silicon wafer. Microscopic polystyrene latex spheres are deposited at four distinct spot locations along the wafer's edge at an arc length of approximately 25 mm, and 10 mm deep.
cross section of psl standard wafer
A PSL particle standards wafer cross section schematic of the ECS.

TAKE YOUR METROLOGY TO THE BRINK. The Edge Contamination Standard (ECS) is a bare silicon wafer that has microscopic latex (PSL) spheres which have been spot deposited on the wafer's edge. The Edge Contamination Standard PSL particle standard wafer is designed for particle size standards calibration of instruments that detect and size particles standards on the substrate's wafer edge.

Edge Contamination Standards Product Description

VLSI Standards' particles size standards solution for wafer edge contamination metrology utilizes precise spot deposition of polystyrene latex spheres (PSL) onto four distinct regions on the substrate's wafer edge. Each PSL sphere deposition area covers the top and bottom near wafer edges, the top and bottom wafer bevels, and the apex or true edge of the wafer. The PSL particles standards wafer allows the user to perform both topside and backside wafer inspections to check the complete sensitivity of the edge contamination standard tool.

The PSL spheres deposited on the Edge Contamination Standard are highly spherical, have well-characterized optical properties and a very tight monodisperse size distribution. These parameters make PSL spheres a useful material for the calibration and monitoring of particle counting instruments. These PSL particle size standards come with nominal 0.5 Ám, 1.0 Ám, 2.0 Ám and 5.0 Ám PSL particle sizes. Approximately a few thousand PSL particles are located in each deposited region.

Although VLSI Standards PSL wafers provides you with the PSL particle count value on the calibration certificate, the Edge Contamination Standard ECS is designed to calibrate particle size standards and tool sensitivity, and not necessarily PSL particle count.

Edge Contamination Standards Product Specifications

  • SEMI Specification Silicon Wafers
    200 mm and 300 mm diameter silicon wafers

  • Deposition Locations
    From notch (0°): 35°, 145°, 205°and 325°

  • Polystyrene Latex Spheres
    Nominal 0.5 Ám, 1.0 Ám, 2.0 Ám and 5.0 Ám diameter (all on one wafer)

  • Traceability
    Traceable to SI Units through NIST

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