銅化學氣相沈積基本特性及以Ni和NiSi為銅擴散障礙層之熱穩定性研究

Abstract

銅化學氣相沈積被認為是一種具有潛力的深次微米新製程技術，本論文以一種液態有機金屬複合體Cu(hfac)TMVS+2.4%TMVS作為先驅物進行銅化學氣相沈積，探討在500 mtorr定壓下沈積所得銅膜之電阻率及表面型態與沈積溫度的關係，以及退火處理對銅膜的影響，並且完成一0.18□m、高寬比為5.5的管洞充填。另一方面，本論文亦探討以Ni及NiSi當作銅擴散障礙層的熱穩定性，實驗結果顯示，厚度40nm的Ni及厚度70nm的NiSi均可有效阻擋銅的擴散至300oC。但是，增加Ni障礙層的厚度，並未能明顯改善阻擋銅擴散的結果。

Chemical vapor deposition (CVD) of Cu has been regarded as a promising technique for future application to deep submicron VLSI process. A liquid metalorganic compound of Cu(hfac)TMVS+2.4%TMVS is used as the precursor to deposit Cu films in this thesis study. At a constant deposition pressure of 500 mtorr, the Cu films film resistivity and surface morphology are investigated with respect to the deposition temperature. The post-deposition annealing effects on the CVD Cu films are also studied. With an appropriate deposition condition, vias of 0.18□m size with 5.5 aspect ratio was conformally filled without any void. This thesis study also investigates the diffusion barrier property of Ni and NiSi for Cu metallization. It is found that the Cu/barrier/p+n junction diodes with a 40 nm thick Ni barrier layer or a 70 nm thick NiSi barrier layer were able to sustain a 30 min thermal anneal at temperature up to 300oC without degrading the diodes characteristics. However, increasing the thickness of Ni barrier layer did not result in effective improvement in the barrier capability against Cu diffusion. 1-1 The Importance of Back-End-Process 1-2 The Advantages of Cu 1-3 The Disadvantages of Cu 1-4 Cu CVD will be Future Mainstream 1-5 Thesis Organization Chapter 2 Multi-Chamber CVD System 2-1 Introduction 2-2 Multi-Chamber CVD System Configuration Chapter 3 The Basic Characteristic of Cu CVD 3-1 Introduction 3-2 Experimental Procedure 3-3 Basic Characteristic of Cu CVD Films 3-3.1 Deposition Rate of Cu Films 3-3.2 Effects of Deposition Temperature on Cu films 3-3.3 Impurity Contamination in Cu Films 3-3.4 Crystal Structure of Cu Films 3-3.5 Effects of Post-Deposition Anneal 3-3.6 Via Filling Capability 3-4 Conclusion and Summary Chapter 4 The Barrier Property of Ni and NiSi for Cu metallization 4-1 Introduction 4-2 Experimental Procedure 4-3 Experimental Result and Discussion 4-4 Summary Chapter 5 Conclusions and Future Work 5-1 Conclusions 5-2 Future Work References