# Analysis of Wafer Warpage in Diamond Wire Saw Slicing Sapphire Crystal  
[PERSON]  
1 Key Laboratory of Manufacturing Equipment of Shaam's Province, Xi'an 710048, China 12 Key Laboratory of High Efficiency and Clean Mechanical Manufacture of MOE, School of Mechanical Engineering, Shandong University, Jinan 25061, China 2  
[PERSON]  
2 Key Laboratory of High Efficiency and Clean Mechanical Manufacture of MOE, School of Mechanical Engineering, Shandong University, Jinan 25061, China 2  
[PERSON]  
2 Key Laboratory of High Efficiency and Clean Mechanical Manufacture of MOE, School of Mechanical Engineering, Shandong University, Jinan 25061, China 2  
[PERSON]  
1 Key Laboratory of Manufacturing Equipment of Shaam's Province, Xi'an 710048, China 12 Key Laboratory of High Efficiency and Clean Mechanical Manufacture of MOE, School of Mechanical Engineering, Shandong University, Jinan 25061, China 2  
Footnote 1:  
is caused by wafer deformation due to sawing heat. However, research in this area is not sufficient. According to the research of [PERSON] et al. [5] and [PERSON] et al. [6], the warpage of sliced wafers is predominantly produced by the non-uniform local thermal expansion of the ingot in the vicinity of the location of the cut during the slicing cycle by the heat generated from the cutting action. [PERSON] et al. [7] studied the temperature field variation of single crystal silicon cut by wire saw using the finite element method. The authors suggested a method to obtain a relatively flat profile of temperature in order to reduce slice warpage due to heat generation during slicing by intelligent control of boundary conditions. [PERSON] et al. [8] used the finite element method to study the temperature field distribution on the outer surface of sapphire ingots cut by the diamond wire saw. The research has found that the maximum temperatures increased with the increase of cutting depth, and were always found to be located in the middle of slicing zone. In addition to the thermal deformation of the wafer itself during slicing processing being able to cause wafer warpage, the thermal deformation of wire guide can also cause the position of the diamond wire to shift, resulting in slice warping. However, this problem can be improved by improving the equipment structure [9]. In addition, the warpage of the wafer during processing is related to its own thickness, and the thickness of the wafer affects its ability to resist deformation [10; 11]. As the wafers move towards a larger size and ultra-thin thickness, their stiffness decreases and their ability to resist warpage and deformation weakens. Based on the research conclusions of comprehensive scholars, during the diamond wire saw cutting process, the temperature in the cutting area increases and heat is generated, causing thermal deformation of the wafer and resulting in warping deformation. The main reason for the difference in warpage of wafers obtained by different sawing processes is due to the inconsistent degree of thermal expansion deformation at different positions of the wafer. So far, there have been no systematic studies on the influence of diamond sawing process parameters on the warpage of sapphire wafers, and there is a lack of understanding of the influence of process parameters on the warpage of wafers. Although it is possible to carry out sawing experiments to conduct analysis and research by measuring wafer warpage, a large amount of data is required. Adjusting different process parameters for sawing and measurement in the experiments is time-consuming, laborious, and of high economic cost. In contrast, the theoretical simulation calculation model embodies the advantages of fast calculation, is time-saving and labor-saving, and has a low economic cost. During the diamond wire saw cutting process, almost all the energy consumed by the diamond abrasives on the surface of the saw wire for crystal cutting is converted into cutting heat.