We mechanically lap wafers prior to probing to obtain a better cosmetic surface after etching and to reduce the total chemical etch time during detector thinning.

While we have developed an in-house lapping process for both die and wafers, we most often use an outside vendor for wafer lapping.

The final wafer thickness after lapping is typically 250 microns.  Polishing to backside surface is also a critical process step since it aids in improved cosmetic quality of the final back illuminated device.