Kim Daekyoung, Kim Hoonbae, Jang Haegyu, Jung Donggeun, Chae Heeyeop
SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University (SKKU), Suwon, 440-746, Republic of Korea.
J Nanosci Nanotechnol. 2012 Jul;12(7):6040-4. doi: 10.1166/jnn.2012.6270.
Ultra low-k dielectric SiCOH films were deposited with decamethylcyclopentasiloxane (DMCPSO, C10H30O5Si5) and cyclohexane (C6H12) precursors by plasma-enhanced chemical vapor deposition at the deposition temperature between 25 and 200 degrees C and their chemical composition and deposition kinetics were investigated in this work. Low dielectric constants of 1.9-2.4 were obtained due to intrinsic nanoscale pores originating from the relatively large ring structure of DMCPSO and to the relatively large fraction of carbon contents in cyclohexane. Three different deposition regions were identified in the temperature range. Deposition rates increased with temperature below 40 degrees C and decreased as temperature increased to 75 degrees C with apparent activation energies of 56 kJ/mol x K at < 40 degrees C, -26 kJ/mol x K at 40-100 degrees C, respectively. In the temperature region of 40-100 degrees C hydrocarbon deposition and decomposition process compete each other and decomposition becomes dominant, which results in apparent negative activation energy. Deposition rates remain relatively unaffected with further increases of temperature above 100 degrees C. FTIR analysis and deposition kinetic analysis showed that hydrocarbon deposition is the major factor determining chemical composition and deposition rate. The hydrocarbon deposition dominates especially at lower temperatures below 40 degrees C and Si-O fraction increases above 40 degrees C. We believe that dielectric constants of low-k films can be controlled by manipulating the fraction of deposited hydrocarbon through temperature control.
采用十甲基环五硅氧烷（DMCPSO，C10H30O5Si5）和环己烷（C6H12）前驱体，通过等离子体增强化学气相沉积法在25至200摄氏度的沉积温度下沉积超低k介电常数的SiCOH薄膜，并对其化学组成和沉积动力学进行了研究。由于DMCPSO相对较大的环状结构产生的固有纳米级孔隙以及环己烷中相对较大的碳含量，获得了1.9 - 2.4的低介电常数。在该温度范围内确定了三个不同的沉积区域。沉积速率在40摄氏度以下随温度升高而增加，在温度升至75摄氏度时下降，在<40摄氏度时的表观活化能为56 kJ/mol·K，在40 - 100摄氏度时为-26 kJ/mol·K。在40 - 100摄氏度的温度区域，碳氢化合物的沉积和分解过程相互竞争，分解占主导，导致表观负活化能。温度进一步升高至100摄氏度以上时，沉积速率相对不受影响。傅里叶变换红外光谱（FTIR）分析和沉积动力学分析表明，碳氢化合物的沉积是决定化学组成和沉积速率的主要因素。碳氢化合物的沉积在40摄氏度以下的较低温度下尤其占主导，而Si - O含量在40摄氏度以上增加。我们认为，可以通过温度控制来控制沉积碳氢化合物的比例，从而控制低k薄膜的介电常数。
