Effect of Abrasive Particle Size on Lapping of Sapphire Wafer by Fixed Abrasive Pad

Abstract

The choice of abrasive particle size is crucial to improve the lapping efficiency and surface quality in lapping of sapphire wafer by fixed abrasive (FA) pad. A model for the penetration depth of a single abrasive is developed with fixed abrasive pad. A serious of lapping tests were carried out using FA pads embedded with different size of diamond particles to verify the validity of the developed model. Results show that the penetration depth of abrasive is related not only to the particle size, but to the hardness ratio of the work-piece to the pad as well. The material removal rate of sapphire is proportional to the square of abrasive particle size, while the average surface roughness is proportional to the abrasive particle size.