為降低金屬導線層間之訊息傳遞延遲，除降低線路電阻之外，亦可開發低介電常數材料，以電漿化學氣相法沈積之類鑽薄膜，除具有約2.8之介電常數外，尚有高熱穩定溫度、高硬度及高電阻等特點，但與其他低介電材料相比，其介電常數仍偏高，因此需要調整製程條件及尋找新碳先驅物，以製備低介電之碳膜。本研究以對二甲苯為碳先驅物，經電漿化學氣相沈積法，製備低介電常數之含氫非晶質碳膜。控制電漿製程參數，包括電漿功率、氬氣流量、乙炔濃度、沈積壓力及熱處理溫度，以獲得不同鍵結、組成比例及化學結構之非晶質碳膜，探討沈積行為對碳膜結構、介電常數及機械性質之影響。
本研究為沈積表面平整且厚度均勻之非晶質碳膜，調整氬氣流量，得到最高沈積速率為40.7 nm/min及最大密度為1.45 g/cm3之碳膜，其源於氬氣流量可控制對二甲苯通量，使從低分子量碳氫鍵結轉變為以sp3碳-氫鍵結為主之碳膜結構，而為區域有序排列之短程碳鏈，最低介電常數為2.28。控制電漿功率，破壞對二甲苯以增加沈積物種量，使碳氫鍵重構為碳碳鍵，最高沈積速率更可高達133.4 nm/min，最大密度也增至1.57 g/cm3，但總介電常數大幅增加至4.73。經鍵結及組成分析，得知電子極化介電只與H/C比例成反比，結構極化介電則因對稱sp3 CH3和sp2 CH鍵結比例增加而降低，而真空極化介電體積則與空孔結構比例相關。
添加乙炔沈積非晶質碳膜，增強對二甲苯電漿聚合反應，調整離子轟擊能量，可控制苯環之沈積物種量與sp3 CH2等碳氫鍵結比例。熱處理後之碳膜結構，傾向形成強鍵之苯環網絡，同時介電常數穩定於2.82。熱處理去除弱鍵而形成的苯環網絡，有助於降低介面結構差異及提高強鍵比例，使最大硬度值為2.37 GPa，與矽基材間最大附著強度為31.87 MPa。

　For decreasing the RC delay between the interconnect metals, the solution is lowering dielectric constant of the interlayer dielectric, besides reducing the electrical resistance of the interconnect. The amorphous carbon films deposited by PECVD have not only a lower dielectric constant near to 2.8, but also thermal stability, high hardness and high electrical resistance. Compared with other low-k material, however, the amorphous carbon films have not enough low dielectric constant and need to improve the process control or search other carbon precursors for preparing the carbon structure with low dielectric constant. The synthesis of amorphous hydrogenated carbon films with low dielectric constant was performed utilizing para-xylene as carbon precursor by plasma-enhanced chemical vapor deposition. Plasma parameters, including deposition power, deposition pressure, argon flow rate, C2H2 concentration and anneal temperature, were controlled to prepare films with different bonding type, element percentage, chemical structure and density. Besides, effects of deposition behavior on film structures, dielectric constant and mechanical proprieties were investigated.
　The a-C:H films with smooth surface and uniform thickness were deposited by controlling the argon flow rate. From the result of characterization, the appearance of sp3 CH2 and CH3 bonds enhances the formation of hydrocarbon bonds and the local ordered arrays of short carbon chains. The a-C:H films with controlled microstructure and chemical bonds were successfully deposited to have a dielectric constant as low as 2.28. The growth rate and density of films deposited by increasing deposition power have the maximum values of 133.4 nm/min and 1.57 g/cm3, respectively. At the same time, the dielectric constant observably increases up to 4.73. According to the variation of dielectric component and FT-IR spectra, it is found that the reduced is only caused by the increase H/C ratio and the reduced is attributed to the increase of the symmetric sp3 CH3 and sp2 CH. Compared with the Raman spectra, the polarization decreases due to the increase of hydrocarbon. Besides, the decrease of dielectric constant can also be originated from the decrease of dielectric volume relating to the incorporation of porous structure, but the effect of polar groups would be significant as the hydrocarbon increases with decreasing deposition power.
　The increase of C2H2 concentration could promote para-xylene to polymerize, such as to enhance the growth rate and further to decrease the density. It is also found that the aromatic ring gradually increases with reducing deposition power, contributing to the increase of hydrocarbon ratio. It is concluded that the polymerization of paraxylene is controlled by the C2H2 concentration for the form of the sp3 and sp2 hydrocarbon bonds. From the FT-IR and Raman spectroscopy, it is found that the size and number of the sp2 carbons are almost fixed but the number of ordered aromatic rings increases with decreasing deposition power. After the annealing treatment, the hydrocarbon bonds and oxygen related bonds on the surface of the as-deposited films are effectively reduced. However, the dielectric constant increases up to 2.82 due to the aromatic networks which also increases the film hardness up to 2.37 GPa as the films are deposited at 50 W and 50 at.% C2H2 after annealing at 400 oC. Nevertheless, the adhesion strength decreases down to 31.87 MPa with increasing the deposition power and acetylene concentration.

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