| 摘要: | 在現今製造業中，線切割技術已廣泛地應用於加工硬脆材料，如陶瓷、玻璃、藍寶石及矽晶錠。線切割的加工過程對於生產高品質的成品至關重要，然而加工過程也伴隨著一系列挑戰與問題，例如破損率的增加、材料表面品質的低劣、殘留應力的存在及加工參數的優化等。本研究第一次提出離散元素法(DEM)配合顆粒鍵接理論，探討線切割的破壞過程與物理機制，並有系統地研究加工參數對晶圓物理性質與表面性質的影響。透過此創新模擬方法，可分析刀具在加工過程承受的力量與力矩，加工後的材料移除率與晶圓表面品質(總厚度變化與翹曲度等)，晶圓內部殘留應力、平均配位數及體積佔有率。為使模擬結果更接近實際物理系統，進行單向度壓縮實驗，並採用實驗設計法校正DEM微觀輸入參數。研究結果顯示：(1) 切割方向的表面總厚度變化(TTV)較進給方向均勻，切割方向的晶圓翹曲度(Warpage)較進給方向平整。(2) 隨著切割速度的增加，鋼琴線力量與力矩逐漸減少，而晶圓殘留應力與剝落率逐漸增加。且較高的切割速度，TTV表現較均勻，Warpage表現較平整。(3) 隨著進給速度的增加、鋼琴線力量、力矩及剝落率逐漸增加，而晶圓殘留應力逐漸減少。(4) 隨著速度比增加，鋼琴線力量與力矩逐漸增加，而殘留應力逐漸減少。(5) 晶棒尺寸與鋼琴線力量、力矩及晶圓殘留應力皆為正相關。;In today′s manufacturing industry, wire-sawing technology is widely applied in processing hard and brittle materials, such as ceramics, glass, sapphire, and silicon ingots. These processing techniques are crucial for producing high-quality products. However, the manufacturing process also comes with a series of challenges and problems, including increased damage rates, poor surface quality of materials, presence of residual stresses, and optimization of processing parameters. This study first proposes the coupled model of the Discrete Element Method (DEM) and particle bonding theory to investigate the physical mechanisms of wire sawing. The influence of processing parameters on the physical and surface properties of wafers was systematically explored. This innovative simulation approach provided insights into the behavior of the machining processes. The acquired physical properties included forces and moments on the wire, material removal rates, wafer surface quality (total thickness variation and warpage), internal residual stresses, coordination numbers, and solid volume fraction. To attain reasonable simulation results, uniaxial compression tests for bulk solids were conducted, and the methodology of Design of Experiment (DOE) was used to determine the microscopic input parameters for DEM.
Main research findings are summarized below: (1) The total thickness variation (TTV) is more uniform in the cutting direction than in the vertical direction, and the wafer warpage is flatter in the cutting direction; (2) As the sawing velocity increases, wire forces and moments gradually decrease, while wafer residual stresses and removal rates increase. Moreover, larger sawing velocities result in more uniform TTV and flatter warpage; (3) With the increase of feeding velocity, wire forces, wire moments, and removal rates gradually increase, while wafer residual stresses decrease; (4) An increase in the velocity ratio leads to a gradual increase in the wire forces and moments, but a decrease in the residual stresses; (5) The wire forces, wire moments, and wafer residual stresses generally increase with the size of the silicon ingot. |
