The Research On CMP Machining Mechanism And Technology For Sapphire Wafer

Single crystal sapphire wafer has good physical, chemical and potical properties, so it has a wider role in microelectronics, industrial, defense, scientific research and GaN LED substrate areas. As the continuous development of scinece and technology, the accurate requirement become higher and higher for processing precision and surface quality of the sapphire wafer. So sapphire processing technology with high efficiency and low loss make a major obstacle for the developmetn of the sapphire.To solve the above problem, ultra-precision doube-sided polishing machine was used to polish the sapphire with double-sided chamical mechanical polishing processing technology. The CMP processing method don't need complicated processing equipment, was beneficial to batch production, and can get the precise surface and processing efficience, so it can achieve precision processing with low cost and high efficiency. As follow are the main research of this paper:1. While sapphire polishing the contact between mechanical and chemical action from the Dynamic Process was analyzed. Using contact dynamics and hydrodynamics to establish the CMP model among the polishing pad, work piece and abrasive, and analyze the mechanism of mechanical action of the abrasive. By the chemical action of polishing slurry for sapphire, the effect of CMP processing for the sapphire surface was analyzed.2. To improve the removal of the sapphire and the quality of the surface, ultra-precison double-sided polishing machine was used to polish the sapphire. Selecting the different polishing slurry for the sapphire CMP processing, FA/O polishing slurry with SiO2 as abrasive was most suitable. Also,the parameters of the polishing speed, polishing pressure and concentratons of the polishign slurry as to the influence of the removal and the surface quality was studied, and the ideal processing parameters were obtained through the experimental comparison.3. Established a modell to predict the sapphire removal with different processing parameters by BP neural network and MTLAB simulation.4. By the better processing parameters being adopted to the sapphire optimization experiment, sapphire surface removal get better and reach the mirror requirement. using optical microscope and white light interferometer, the sapphire surface after optimization polishing was tested and analyzed. After optimization polishing, sapphire surface was basically no scratches pits and other defect, and has been significantly improved,at the same time get the good surface roughness.