Brumley South Introduces the In House ability to produce SiO2 Calibration Standards
- A Wafer Inspection Contamination Calibration Standard using Silica Nanoparticles
- Certified, NIST Traceable, size standard deposited on a prime silicon wafer or Substrate of your Choice, at a specific size peak with narrow size distribution
- 10 nanometer to 10um particle wafer standards are can be custom built to your specifications
- Deposition Coverage includes Full, Circle, Half or Custom Design across the surface
- Silica Contamination Wafer Standards are used to calibrate the size accuracy response of scanning surface inspection systems (SSIS), tools using high powered lasers, such as the KLA-Tencor SP2, SP3, SP5, SPx, SEM tools and TEM
- Using normal PSL Polystyrene Latex Spheres will melt on these tools when ran at high laser power
The size response curves of wafer inspection systems using high powered, scanning lasers from KLA-Tencor and Hitachi require calibration. The traditional calibration method was to use PSL Wafer Standards, but PSL spheres are found to shrink under intense laser power. Silica particles are more robust than Polystyrene Latex Spheres with respect to laser energy. The laser intensity of a KLA-Tencor Surfscan SP1 and Surfscan SP2 tools use lower power lasers; while the newer KLA-Tencor Surfscan SP3, SP5 and SPx tools, as well as the patterned wafer inspection systems from Hitachi, all use higher powered lasers.
In the past, wafer inspection systems would use PSL Wafer Standards deposited with PSL Spheres to calibrate the size response curves of those wafer inspection tools. As laser power increases, PSL Spheres tend to shrink under high laser intensity, resulting in a decrease in true PSL size diameter. This of course would affect each size calibration of that tool, repeatedly using the same PSL Wafer Standard. The result would be a misleading, decrease in particle, laser size response with repeated laser scans of the PSL Wafer Standard.
SiO2 particles and PSL Spheres are very close in refractive index. When both types of particles are deposited on a prime silicon wafer and scanned by a wafer inspection tool, the laser size response curves of Silica and PSL Spheres are similar. Because Silica nano-particles can withstand more laser energy, shrinkage is not a concern with the present level of laser power being used in wafer inspection tools.
Contamination Wafer Standards using silica particles can be used to produce a true particle, size response curve; which is quite similar to the response curve using PSL Spheres. Size calibration of particle size response curves using Silica particles allows the transition from PSL Wafer Standards (normally used with the older, lower powered SSIS wafer inspection systems) to a Contamination Wafer Standard using silica particles for the higher powered SSIS tools. Wafer Standards deposited at 100 nano-meters diameter and above are scanned by a KLA-Tencor Surfscan SP1, whereas Wafer standards below 100nm particle size would be scanned by a KLA-Tencor Surfscan SP5.
*This source of information was used with premissiom from: www.AppliedPhysicsUSA.com