低介電常數旋塗式玻璃薄膜之化學機械拋光特性研究

Abstract

化學機械拋光製程被公認為能夠達到全域平坦化最有效的方法。在本論文 中，我們對一系列的旋塗式玻璃薄膜做了詳細的探討，從表面性質及分子 鍵結的構造來對這些薄膜的特性能有深入的瞭解，同時我們也利用這些特 性進一步探討含有有機成份的旋塗式 玻璃薄膜在化學機械拋光過程中的 拋光機制。在本實驗中我們將不同有機成分含量的烷基矽氧烷為基底的旋 塗式玻璃薄膜使用氧化矽或氧化鋯為拋光液，在這些拋光液中加入不同添 加劑來評估這些薄膜的拋光結果，實驗結果發現，使用鹼性氧化矽水溶液 為拋光液的有機介電薄膜，其拋光速率很低，相反地，使用酸性氧化鋯溶 液為拋光液的有機介電薄膜，可以有效提高拋光速率。另外，我們也發現 在酸性氧化鋯溶液加入不同碳數的氫氧化四級銨，可選擇性提高有機成分 的介電薄膜之拋光速率而抑制不含有機成份的介電薄膜之拋光速率，亦即 調整氫氧化四級銨之加入量可改變製程所需的選擇率（1.2∼9.1）。對於 化學機械拋光後的這些薄膜，我們也發現其成份並沒有改變，顯示這些薄 膜適合於化學機械拋光的製程上應用。 Chemical-mechanical polishing (CMP) process has been proven to be the most promising method for accomplishing global planarization. In this study,chemical-mechanical polishing of spin-on glass (SOG) thin films are presented. Wettability, surface property and bonding structure of spin-on glasses are characterized in order to evaluate their correlations with CMPperformance. Alkylsiloxane-based spin-on glass (SOG) thin films with varying amounts of organic content were subjected to CMP using silica- and ZrO2-based slurries with a variety of additives. As the amount of organic content in SOG increases, removal rate dec reases with silica-based KOH-stabilized slurry. On the other hand, higher removal rates for both organic SOG and thermal oxide were obtained with ZrO2-based slurry than those obtained with SiO2-based slurry and adjustment in polish selectivity (relative to thermal oxide) ranging from 1.2 to 9.1 can be achieved by adding various amount of tetra-alkyl substitute ammonium hydroxide. Post-CMP SOG films characterized by Fourier-transform infrared (FTIR) spectroscopy and atomic force microscope (AFM) are moisture-resistant and chemically stable, thus can be considered to be CMP-compatible.