臺灣博碩士論文加值系統

本論文目的是利用有限元素法，建立化學機械研磨的二維軸對稱準靜態模式，分析化學機械研磨(Chemical-mechanical Polishing,簡稱CMP)過程中，晶圓承載器施壓於晶圓表面與研磨墊後，晶圓表面的應力分佈趨勢與表面變形狀態，並透過晶圓承載器之維持環機構與背壓的使用，改善晶圓表面應力分佈與變形狀態，以降低表面不均勻度(Non-Uniformity)為目的。
首先由改變研磨墊與載具膜的彈性模數與厚度來觀察表面應力分佈趨勢的變動情形，並找出軸向應力與變形為影響表面研磨速率(Removal Rate)的影響因子。其次，由於晶圓邊緣的應力集中所產生的邊緣過度磨耗使得晶圓表面不均勻度提高常為CMP製程中的瓶頸，本文提出了利用維持環機構在研磨墊上施壓所產生的軸向與環向拉力，拉伸晶圓邊緣的材料以降低邊緣材料的變形量，抑制邊緣效應的情形，而降低了晶圓表面的不均勻度，並提出較佳的維持環機構設計參數選擇。
最後，再利用在載具膜上挖孔，由孔中通入氣壓的方式，以不同的多孔性氣壓分佈來補償晶圓表面的應力分佈與變形，由本文之模擬結果可知，以區域性漸進式之補償背壓將能最有效地降低材料因邊緣過磨而產生的不均勻度升高情形。

A two-dimensional axially symmetric static model for chemical-mechanical polishing (CMP) is established in this paper based on the finite element method. During the CMP process, the carrier exerts pressure on the wafer surface and the pad. In this study, the mechanism of the retain ring and back pressure are utilized to improve the pressure distribution and deformation of wafer surface to achieve the objective of reducing surface non-uniformity.
First, we observed the variation of surface pressure distribution through the modulus of elasticity and thickness of the pad and carrier film, and found the axial stress and deformation to be the decisive factors of surface removal rate. The edge over-polishing derived from the stress concentration on the wafer edge increased the non-uniformity on wafer surface, which often becomes the bottleneck in the CMP process. In this paper, we use the retain ring mechanism to exert pressure on the pad to generate axial and hoop pulling forces that pull on the material at wafer edge and reduce the extent of material deformation. The reduction limits the edge effect and thus reduces the non-uniformity on wafer surface. The selection of optimal design parameters for the retain ring mechanism is also presented in the paper.
Finally, pores are made on the carrier film to conduct air pressure through the pores. Then different porosity air pressure distributions are used to compensate for the pressure distribution and deformation on the wafer surface. According to simulation results derived in this paper, regional and gradual compensating back pressure is the most effective means of reducing the rise of material non-conformity due to over-polishing on the edge.

中文摘要 I
Abstract II
誌謝 III
目錄 IV
圖表目錄 VI
第一章 緒論 1
1.1 前言 1
1.2 研究動機 2
1.3 文獻回顧 3
1.4 論文架構 5
第二章 化學機械研磨加工法簡介 7
2.1 化學機械研磨之簡介 7
2.2 化學機械研磨之研磨機構 7
2.3 化學機械研磨之作動原理 9
第三章 化學機械研磨有限元素模式 12
3.1 有限元素法概論 12
3.2 準靜態模式之建立 12
3.3 二維軸對稱線彈性之基本方程式 13
3.3.1 應變位移方程式 13
3.3.2 應力應變關係 14
3.3.3 靜平衡方程式 15
3.3.4 相容性方程式 16
3.4 二維軸對稱有限元素之構成方程式 16
3.4.1 最小總位能原理(虛位移原理) 16
3.4.2 二維軸對稱有限元素方程式 19
3.4.3 二維軸對稱有限元素分析 20
第四章 晶圓表面壓力分析 26
4.1 晶圓承載器基本假設與邊界條件 26
4.2 晶圓表面壓力分析 27
4.2.1 表面壓力模擬結果 27
4.2.2 研磨墊對晶圓壓應力之影響 29
4.2.3 載具膜對晶圓壓力之影響 32
4.3 晶圓表面應力再分析 36
第五章 晶圓承載器之維持環設計 39
5.1 晶圓承載器之維持環模型建立 39
5.2 晶圓承載器之維持環模擬 41
5.3 模擬結果與討論 42
第六章 晶圓承載器之背壓分析 56
6.1 晶圓承載器背壓分析之模型建立 56
6.2 晶圓承載器之背壓模擬 57
6.3 晶圓承載器之背壓討論 67
第七章 結論與建議 69
7.1 結論 69
7.2 建議 70
參考文獻 71

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