Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/2309
標題: 化學機械拋光磨耗機制之研究
A STUDY OF WEAR MECHANISMS FOR CHEMICAL MECHANICAL POLISHING
作者: 劉大中
Chung, Liu La
關鍵字: 化學機械拋光;CMP;磨耗;wear
出版社: 機械工程學系
摘要: 
在積體電路(IC)工業中,由於元件設計日趨複雜及深次微米結構的需求,因此晶圓表面的平坦度必須提高,以配合微影製程的需求。化學機械拋光(CMP)較其他拋光方法更能達到全面性平坦化的效果而廣為IC製程所採用,然而CMP製程的機制還未能充分掌握,本文以機械應力的觀點,探討化學機械拋光過程的液動磨耗機制及磨粒磨耗機制,再經由銅被覆層的CMP實驗結果探討拋光過程中,機械作用所造成的影響及其對於表面材料移除的關係。
研究主要發現包括(1)在液動磨耗機制中,若不考慮化學反應的作用,是無法達到材料移除效果。(2)由模擬分析得知壓力對移除率的影響並非完全為線性關係。(3)從實驗數據的整體變化趨勢來看,轉速改變對於移除率的影響較壓力變化明顯,故剪應力對於材料移除的效果較正向應力為強烈。(4)軟質拋光墊的移除率實驗值與理論分析的趨勢相近,故磨粒磨耗理論較適用於軟質拋光墊之拋光過程。(5)在不含磨粒的漿料實驗下,因為壓力的增加而導致薄膜厚度的下降,在漿料供給不足的情形下,減少了化學反應的機會,故在純機械力的作用下,材料移除的效果較不明顯。(6)背壓的大小以及拋光墊性質的軟硬程度,會影響CMP的不均均性。(7)實驗所量測的表面粗糙度值隨壓力增加而有變差的趨勢,而此變化的趨勢與理論模擬之刮痕深度相同。

The increasing complexity of devices and the emergence of deep submicrometer structures in integrated circuit (IC) industry require minimum surface topographies of wafer for lithography process. Chemical mechanical polishing (CMP) has been used in the planarization of wafer surfaces as, compared to other planarization processes, it can achieve global planarization. However, the process mechanism of CMP is not well understood yet. This thesis, from the mechanical viewpoint, investigates the fluid-based and abrasive-based wear mechanisms. Experiments are designed and conducted to verify the mechanisms and to understand the relationship between material removal and mechanical parameters.
Achievement of this study includes the following items. (1) Material on wafer surface cannot be removed by hydrodynamic effects without chemical reaction. (2) The relationship between the material removal rate (RR) and the applied polishing pressure is not linear. (3) Experimental data shows that polishing velocity has higher effect than polishing pressure on RR. That is, RR depends stronger on the shear stress than on the normal stress. (4) RR based on soft pad matched better with theoretical value. It is observed that abrasive-based wear mechanism is suitable for CMP with soft pad. (5) It is also observed from abrasive-free polishing that RR is not obvious when polishing pressure increases. This is caused by the decrease of slurry between the wafer and the pad due to the increasing pressure and thus reduces the chemical reaction. (6) Non-uniformity (NU) of wafer is highly affected by the back pressure and stiffness of pad. (7) Surface roughness increases as polishing pressure increases. The trend, however, is similar to the theoretical value of scratch.
URI: http://hdl.handle.net/11455/2309
Appears in Collections:機械工程學系所

Show full item record
 
TAIR Related Article

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.