Park Yonggyun, Liu Pengzhan, Lee Seunghwan, Cho Jinill, Joo Eric, Kim Hyeong-U, Kim Taesung
School of Mechanical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea.
ComdelKorea, Ltd., 120 Heungdeokjungang-ro, Giheung-gu, Yongin 16950, Republic of Korea.
Sensors (Basel). 2023 Jun 14;23(12):5563. doi: 10.3390/s23125563.
This study identified time-varying harmonic characteristics in a high-density plasma (HDP) chemical vapor deposition (CVD) chamber by depositing low-k oxide (SiOF). The characteristics of harmonics are caused by the nonlinear Lorentz force and the nonlinear nature of the sheath. In this study, a noninvasive directional coupler was used to collect harmonic power in the forward and reverse directions, which were low frequency (LF) and high bias radio frequency (RF). The intensity of the 2nd and 3rd harmonics responded to the LF power, pressure, and gas flow rate introduced for plasma generation. Meanwhile, the intensity of the 6th harmonic responded to the oxygen fraction in the transition step. The intensity of the 7th (forward) and 10th (in reverse) harmonic of the bias RF power depended on the underlying layers (silicon rich oxide (SRO) and undoped silicate glass (USG)) and the deposition of the SiOF layer. In particular, the 10th (reverse) harmonic of the bias RF power was identified using electrodynamics in a double capacitor model of the plasma sheath and the deposited dielectric material. The plasma-induced electronic charging effect on the deposited film resulted in the time-varying characteristic of the 10th harmonic (in reverse) of the bias RF power. The wafer-to-wafer consistency and stability of the time-varying characteristic were investigated. The findings of this study can be applied to in situ diagnosis of SiOF thin film deposition and optimization of the deposition process.
本研究通过沉积低介电常数氧化物（SiOF），确定了高密度等离子体（HDP）化学气相沉积（CVD）腔室中的时变谐波特性。谐波特性是由非线性洛伦兹力和鞘层的非线性性质引起的。在本研究中，使用非侵入式定向耦合器收集正向和反向的谐波功率，分别为低频（LF）和高偏置射频（RF）。二次和三次谐波的强度对用于产生等离子体的低频功率、压力和气体流速有响应。同时，六次谐波的强度在过渡步骤中对氧分数有响应。偏置射频功率的七次（正向）和十次（反向）谐波强度取决于底层（富硅氧化物（SRO）和未掺杂硅酸盐玻璃（USG））以及SiOF层的沉积。特别是，利用等离子体鞘层和沉积介电材料的双电容模型中的电动力学确定了偏置射频功率的十次（反向）谐波。等离子体对沉积薄膜的电子充电效应导致了偏置射频功率十次（反向）谐波的时变特性。研究了这种时变特性在晶圆间的一致性和稳定性。本研究的结果可应用于SiOF薄膜沉积的原位诊断和沉积工艺的优化。
