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Calibration wafers

Danchip has three calibration wafers for the KLA-Tencor Surfscan. The calibration wafers are 6" silicon wafer with a number of polystyrene-latex (PSL) spheres uniformily spread over the surface. Diameter of PSL spheres:

0.204 µm spheres
1.112 µm spheres
4.000 µm spheres

Uniformity check

Acceptance criterion:

10 scans are done on each of the three PSL calibration wafers.. Load/unload to the cassette every time. The the repeatbility of +/- 1σ should be less then 1%.

Results

0.204 PSL calibration wafer:

1.112 PSL calibration wafer:

'4.000 PSL calibration wafer:

Handling test

Acceptance criterion:

Run a cassette of 25 wafers. The machine should be able to error-free handle the cassette 40 times, i.e. it should be able to handle 1000 wafers withot faling.

Results

6" cassette":

A cassette of 25 wafers was handled 40 times over night, i.e. the acceptance criterion was meet.

4" and 8" cassette:

A cassette of 25 wafers was handled two times. The scanning was then stopped to save time as we do not expect handling of more cassettes to caused problem.-s