Performance of thermal field-assisted precision lapping for single crystal sapphire wafers

Abstract

To address the issues of poor surface quality and low efficiency in conventional sapphire wafer lapping processing, a thermal field-assisted processing technology was proposed. The influence of thermal field-assistance on sapphire wafer lapping performance was investigated. While controlling the temperature of the processing area with a self-designed thermal field-assisted device, the lapping tests of sapphire wafers were performed under different processing area temperatures using a semi-fixed flexible machining tool. The effect of processing area temperature on lapping performance was thoroughly examined, along with the material removal mechanism. The simulation results show that the processing area can be quickly heated by a self-designed thermal field-assisted device, and the temperature difference between different areas of the wafer is less than 1.3℃. When the processing area temperature was controlled at 50℃, the surface roughness of sapphire wafers decreased by 6%, and the material removal rate (MRR) improved by nearly 114.2% compared to room temperature. The wear debris test results show that with the increase in processing area temperature during the removal process, the crystal structure of the wafer surface material changed, leading to an improved hydration reaction rate during processing and resulting in a high MRR. Thermal field-assisted precision lapping of sapphire wafers can achieve high surface quality while also increasing processing efficiency, which has a wide range of applications.

Keywords

• sapphire wafer
• thermal field-assisted
• precision lapping
• surface roughness
• removal mechanism