Papers by Keyword: Multi-Wire Saw

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Authors: Ken Ichi Ishikawa, Hitoshi Suwabe, Shun-Ichi Itoh, Michio Uneda
Authors: S.Q. Peng, Y.X. Dai, Y.B. Zhang, Jin Jiang, Ju Long Yuan
Abstract: Multi-wire sawing is a novel method for slicing silicon. The tension control of wire is a vital factor that has impaction on the slicing process. Along with the modern wind machine developing to higher speed and precision, tension control technology becomes more important. This paper introduces a closed-loop tension control system with the digital signal processor (DSP) with function modules as its control kernel, the alternating current (AC) servo motor as execute element and the radius-following device to accomplish the real-time radius compensation. The mechanism of the tension control system is analyzed and the numerical model is set up. The compensation technique of the radius of the scroll is analyzed. Experimental results show that the system is well qualified with high control precision and high reaction speed.
Authors: Hyoung Jae Kim, Do Yeon Kim, Sang Jik Lee, Hae Do Jeong, Hon Jong Choi
Abstract: Diamond abrasive coated wires are core tools for precision multi-wire sawing of mono-crystal ingots for substrate manufacturing, especially for hard materials applications such as SiC, GaN, sapphire and silicon. However, repeated contact by reciprocation motion of wire makes it difficult to design optimized utilization of diamond wires since it makes temporal change in cutting performance due to gradual wear of abrasives. In this paper, the cutting performance of wires are examined based on experimental results with wires having different concentration. The results indicated that the concentration of diamond abrasives have strong relationship with cutting performance and wires with low concentration showed higher material removal characteristics.
Authors: Jing Liang He, He Yuan Dong, Xiao Yan Ye, Xue Jun Wang
Abstract: On the basis of the analysis of winding drive system’s technological requirements of multi-wire cutting system and the characteristics of torque motor, the article proposes a scheme of wrap wheel with torque motor control to overcome the deficiency of the general control motor driven wrap wheel. In determination process of winding system parameter, it provides the selective calculation methods and the control strategy of the torque motor. According to processing materials, we get tension values, and then calculate the output torque, and choose a suitable torque motor and determine the control strategy. Then the design process of winding drive system finishes. Adopting the torque motor as wrap wheel control motor can make wrap device to meet the system requirements. Meanwhile it can simplify the structure of wrap device, and make the cutting-process runs smoothly.
Authors: Yoshinori Abe, Ken Ichi Ishikawa, Hitoshi Suwabe
Abstract: Warp accuracy and nanotopography in the silicon wafer slicing process influence the final quality of the wafer. Therefore, methods to improve these factors are important. And this will require the achievement of low costs and high quality processing – conflicting requirements – with larger sized wafers than in previous generations. The present study was performed to assess mechanical factors, such as machine static accuracy and thermal deformation, to improve the accuracy of multi-wire saws. This report deals with the influence of thermal deformation of the ingot and wire guides upon processing accuracy, and describes the assessment results.
Authors: Satoshi Sakamoto, Keitoku Hayashi, Yasuo Kondo, Kenji Yamaguchi, Tsuyoshi Fujita, Takao Yakou
Abstract: Thinning of the silicon wafers and decrease in kerf loss can minimize the production costs of semiconductor products. Currently, the quantity of kerf loss is about the same as the volume of the wafer itself. If we drastically reduce kerf loss, we can easily lower production costs. Therefore, we studied techniques for slicing silicon wafers with reduced kerf loss using a wire tool. As a first step, we performed micro-grooving with a fine wire tool. In this paper, we discuss the micro-grooving performance of a fine wire tool made of tungsten. A borosilicate glass is used as the work material. The main conclusions are as follows: When a fine wire tool and small-diameter abrasives are used, the kerf loss decreases. However, the strength of fine wire tools is very low. The relative velocity and abrasive diameters have a significant influence on the micro-grooving characteristics. Fine wire tools are easily fractured at fast relative velocities and with large-diameter abrasives. However, the grooving rate increases. Groove depth and grooving efficiency do not depend on the relative velocity and are dependent on the abrasive diameter.
Authors: Jin Jiang, Y.X. Dai, Y.B. Zhang, R. Tang, Wan Li Xiong
Abstract: Aimed at the problem of multi-motor synchronization in multi-wire saw, Strategy based on model-free adaptive control (MFAC), which has some characteristics such as without accurate system model, without system identification and without complicated manual tuning, is produced. MFAC is based directly on pseudo-partial-derivatives (PPD) derived on-line from the input and output data of the system using a novel parameter estimation algorithm. It is suitable for multi-wire saw in such a complex system which is nonlinearity, strong interference and strong coupling. Overall design of multi-wire saw is analyzed. Control structure of multi-motor is given. Motion model of multi-motor synchronization is established. To speed of main motor for reference, supply spool motor and collect spool motor, which have similar dynamic characteristics with main motor, are adjusted adaptively to follow operation of main motor, and synchronization motion is ensured. The prototype experiments show that the method used is right and feasible.
Authors: R. Tang, Y.X. Dai, Y.B. Zhang, Ju Long Yuan, Wan Li Xiong
Abstract: The deflection of cutting wire on multi-wire saw is determined by cutting wire tension, diameter ingot feed force and some other factors, and it affects the quality of silicon wafers greatly. In this paper, the initial stage of cutting process is analyzed and modeled with three ODEs. Then the numerical solutions are solved by finding out the BVPs of each ODE. The numerical solutions showed the relationship between the deflection and the cutting parameters such as cutting wire tension, diameter and ingot feed force. This method is helpful for the further research of modeling the entire cutting process.
Authors: Moriyama Shinya, Takanori Yazawa, Tatsuki Otubo
Abstract: This work examined improvements in cutting efficiency obtained during the slicing of sapphire workpieces when adding CeO2 to the cutting fluid. Various machining parameters, including the cutting temperature, machining surface tolerance, surface quality and tool wear, were assessed. It was confirmed that both the cutting temperature and the machining surface tolerance are reduced by the presence of CeO2 in the cutting fluid. Observations of the machined surfaces and the cutting tool also demonstrated that both brittle fracturing of the surface and loss of abrasive grains were suppressed following the addition of CeO2. These results suggest that the cutting temperature likely affects the accuracy of the cutting process and that CeO2 appears to improve cutting efficiency by reducing the workpiece temperature and by stabilizing the cutting process.
Authors: Satoshi Sakamoto, Mitsugu Yamaguchi, Yasuo Kondo, Kenji Yamaguchi, Alisa Jean Nomura
Abstract: Anisotropic materials are used in various fields because of their superior mechanical properties such as high specific strength. However, the surface generation mechanism in loose abrasive machining such as multi-wire sawing of anisotropic materials has many unknown characteristics. This study mainly aims to clarify the sliced surface generation mechanism in multi-wire sawing of glass fiber reinforced plastics (GFRP). Therefore, the slicing experiments and the wet lapping experiments are carried out in this study. In this paper, we describe the fundamental slicing characteristics of GFRP and the influence that the orientation angle of reinforcement fibers has on the newly generated surface of GFRP. We find that high-precision machining of GFRP is possible using a multi-wire saw. The slicing rate and thickness variation are not dependent on the orientation angle. However, sliced surface roughness depends on the orientation angle, and it tends to decrease when the orientation angle increases. In addition, sliced surface generation and polished surface generation involve similar mechanisms and produce very similar surface characteristics.
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