Processing performance of vitrified bonded fixed-abrasive lapping plates for sapphire wafers

Abstract

To enhance the lapping effects of sapphire wafers, two vitrified bonded fixed-abrasive lapping plates with different mechanical properties were developed and used to lap sapphire wafers to evaluate the effects of lapping time and dressing cycle on the lapping process effect and the stability of the lapping plates. The results indicate that the lapping material removal rate (MRR) and surface roughness (Ra) of the workpiece decrease with increasing lapping time; the higher the hardness of the lapping plate, the larger the MRR and Ra. There are differences in the primary wear forms between the two types of plates, with the high-hardness plate being mainly abrasive wear and abrasive breakage, while the low-hardness plate being mainly abrasive peeling off and abrasive wear. The two plates have the same trend in material removal for sapphire wafers - increasing the lapping time, the MRR is found to be gradually decreased and plateaued after 30 min, which is only about 20% of that of the initial lapping time, resulting in the plates needing to be dressed. After dressing the lapping plates, the plate processing performance returns to its initial state; the MRR deviation is less than 10% within the same period of use after several dressings.