應用在超大型積體電路的新低介電常數聚合物之特性研究

Abstract

本論文探討低介電常數聚合物HOSP應用於超大型積體電路時，HOSP薄膜本身的熱穩定性和電性。我們利用傅立葉轉換紅外線吸收光譜儀、橢圓測厚儀及N&K分析儀來探討薄膜本身的熱穩定性。在電性方面，則使用電容量測、電流-電壓、電容-電壓及加溫偏壓法並配合不同的金屬電極（鋁電極和銅電極）來探討各項電性。同時也輔以二次離子質譜儀及熱脫附質譜儀探討HOSP薄膜特性劣化的原因。實驗結果顯示，HOSP的介電常數很低，約在2.5左右，這主要是因為籠狀結構可以降低薄膜的密度所致，另外矽-碳鍵的極性小於矽-氧鍵的極性也是一個可能的因素；而熱穩定性也可以到達500℃。除了用傳統爐管做熱處理外，我們也研究了利用電漿做熱處理對薄膜特性的影響。最後，則討論了HOSP薄膜對銅的阻擋特性。我們發現當製程溫度增加的情況下，銅離子會擴散至HOSP薄膜中。

This thesis mainly investigates the thermal stability and electric properties of a low-K material ― HOSP. The dielectric constant of the HOSP film is determined to be around 2.5, and the HOSP film is found to be thermally stable up to 500℃ obtained by FTIR analysis and TDS measurement. The low dielectric constant of the HOSP is due to its cage-like structure, which looses the film density. Substitution of Si-C for highly polarized Si-O is another possible reason. The capacitance, I-V and C-V measurements as well as Bias-Temperature Stress (BTS) test were used to characterize the electric properties of the HOSP MIS capacitors. In addition, the effects of plasma curing have also been studied. Finally, we studied the barrier properties of the HOSP film. Presumably, Cu penetrates into the HOSP film and resides in the form of Cu ions, as the annealing temperature is increased. Abstract (English)…………………………………………………………ii Contents……………………………………………………………………iii Table Captions………………………………………………………………v Figure Captions……………………………………………………………vi Chapter 1 Introduction……………………………………………………1 1.1 General Background…………………………………………………1 1.2 Motivation and Material Options…………………………………2 1.3 Organization of This Thesis………………………………………3 Chapter 2 Experimental Procedures……………………………………9 2.1 Process Description…………………………………………………9 2.1.1 Sample Preparation……………………………………………9 2.1.2 Coating Process…………………………………………………9 2.1.3 Bake/Cure Process………………………………………………9 2.1.4 Capacitor Fabrication………………………………………10 2.1.5 Flow Chart………………………………………………………10 2.2 Characterization Methods…………………………………………10 2.2.1 Material Analysis……………………………………………10 2.2.1.1 Thickness and Refractive Index Measurements………10 2.2.1.2 Fourier Transform Infrared (FTIR) Measurement……10 2.2.1.3 Stress Measurement………………………………………11 2.2.1.4 Thermal Desorption-Atmospheric Pressure Ionization Mass Spectrometer (TD-APIMS) Measurement…………12 2.2.1.5 SIMS Measurement…………………………………………12 2.2.2 Electrical Measurement………………………………………12 2.2.2.1 Current versus Voltage (I-V) Measurement…………12 2.2.2.2 Capacitance versus Voltage (C-V) Measurement……13 2.2.2.3 Bias-Temperature Stress (BTS) Method………………13 Chapter 3 Results and Discussion……………………………………19 3.1 General Properties…………………………………………………19 3.1.1 Material Descriptions………………………………………19 3.1.2 Uniformity………………………………………………………19 3.1.3 Film Shrinkage…………………………………………………20 3.1.4 Dielectric Constant and Refractive Index………………21 3.1.5 FTIR Measurement………………………………………………21 3.2 Thermal Stability…………………………………………………22 3.2.1 Hot Plate Bake Effects………………………………………23 3.2.2 Furnace Cure Effects…………………………………………23 3.2.3 Plasma Cure Effects…………………………………………25 3.3 Film Stress…………………………………………………………28 3.4 TD-APIMS Measurement………………………………………………29 3.5 Thermal Cycle Effect………………………………………………30 3.6 Post Metallization Annealing Effects…………………………31 3.6.1 The effects of Cu on this material………………………31 3.7 Electrical Property of HOSP……………………………………32 3.7.1 Structure Determination……………………………………32 3.7.2 Hysteresis Effect……………………………………………33 3.7.3 Bias-Temperature Stress……………………………………34 Chapter 4 Conclusions..…………………………………………………69 References..…………………………………………………………………71