Papers by Author: Gang Xiang Hu

Abstract: This study compares the effectiveness of different polishing slurries for Double Sided Polishing process of Silicon wafer in the polished surface roughness and stock removal rate, discusses the mechanism of Double Sided Polishing for silicon wafer with different type slurries, also the influence of the pH value, temperature and concentration of the slurries are discussed in this paper. Furthermore, by the optimization of the process parameters, the ultra-smooth of polished surface of silicon wafer has been got with higher efficient.

Abstract: A reasonable finite element (FE) model of grinding temperature field has been developed on the basis of analysis of the transient temperature field， and three kinds of boundary conditions are loaded on the element of a moving heat source. The study, which is based on the finite element principle, has been carried out using the numerical simulation software ANSYS. Many results have been obtained including three dimensional temperature distribution map. The simulated results under different conditions show good agreement with the experimental results. With the comparison of the dry-grinding and wet-grinding, the result shows that the wet-grinding temperature with a proper grinding fluid is rather lower than the dry-grinding temperature. Finally, the variable coefficient of convective heat transfer and the different form heat source have been discussed in detail.

Abstract: Double sided polishing process has become a main machining method for silicon wafer finishing process, but it is difficult to get ultra-smooth surface with the very stringent machining conditions. In this paper, the mechanism of ultra-smooth surface machining process was studied, the main parameters affecting the surface quality of silicon wafer, such as the polishing pad and carrier rotation speed, polishing press, polishing slurries etc. , were discussed and optimized, then ultra-smooth surface of silicon wafer with Ra 0.4nm has been obtained based on the above study. A new double sided polishing machine with computer control system equipped with a digital controlled press valve was developed, and the ultra-smooth machining process of silicon wafer was established in this paper.

Abstract: The functional materials such as sapphire, silicon wafer etc. are processed efficiently with ultra-smooth surface for the demand of the rapid development of the IC industry. The precise double sided polishing process is one of the main methods of getting the ultra-smooth surface for these materials. This paper introduces the structure and characteristic of the precise double sided polishing machine with a precise pressure control system equipped a new type electro-pneumatic digital servo valve. The works, such as machine design, development of the control system and optimization of process parameters etc. are carried out to meet the requirement of the precise double sided polishing machining process. This equipment has the characteristic of high machining precision and precise control capability, so it can be applied to the ultra-precise machining of the ultra-thin sapphire, silicon wafers etc.

Abstract: This paper discussed the principle about the Electrical Discharge Truing(EDT) technique ,which applied in lapping machining process, including EDT status with different environment and machining conditions, and an EDT equipment on a lapping machine have been developed and used in the experiment of EDT. Then some experiments were carried out for verifying of the EDT effect with different EDT parameters such as electric voltage, EDT gap, and the EDT media. Finally, the efficient and precision EDT was achieved with the suitable EDT parameters.