Pressure Distribution and Wear of Grinding Wheel in Ultra-Thinning Process of LiTaO3 Wafer

Abstract

The flat surface of a thin LiTaO₃ substrate, exhibiting excellent electro-optical and piezoelectric properties, is required to enhance surface acoustic wave energy. A high-quality surface of a thin LiTaO₃ substrate can be obtained through ultra-thinning processes, such as grinding and chemical mechanical polishing. However, during the ultra-thinning process, the grinding wheel gradually wears, leading to an uneven pressure distribution on its surface, which results in machining errors, such as cracks, subsurface damage, and chatter. Hence, the uneven pressure distribution must be examined to maintain and improve machining accuracy. In this study, reciprocating tests and simulations were performed on the grinding wheel of a LiTaO₃ wafer using Archard’s wear model in the commercial software ANSYS Transient Structural. In addition, a grinding simulation was performed, considering the grinding conditions and wear rate, to examine the pressure distribution on the surface of the grinding wheel. In the grinding simulations, the periodic pressure distribution changed at a high frequency of 12,987 Hz on the surface of the grinding wheel, with a maximum pressure of 1.7 MPa. Additionally, modal analysis was conducted to examine the occurrence of resonance, thereby confirming the risk of resonance.