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Bosch工艺在高深宽比刻蚀中的应用愈发广泛，而反应离子刻蚀滞后效应(RIE-lag)仍是约束其刻蚀均匀性及最大深宽比的因素之一。文章采用多尺度仿真，通过耦合全局模型，鞘层模型和刻蚀模型对高深宽比下反应气体为SF6和C_4F8的Bosch工艺刻蚀进行了模拟，研究了各种放电参数对RIE-lag的影响。结果表明，偏压功率和频率均以离子能量角度分布来影响RIE-lag，较低离子能量增加到一定值时，会增加刻蚀前沿的离子数密度，从而使RIE-lag有所改善；而超过该能量值后RIE-lag则会加剧；线圈功率会直接影响气体放电产生的粒子数密度来改变RIE-lag，随着功率的增加，RIE-lag同样呈现出先降低后升高的非单调变化趋势；钝化阶段压力的增加会延长刻蚀钝化层的时间，改善RIE-lag。最后结合Bosch循环中的时间序列与刻蚀深度关系图分析发现，偏压功率、偏压频率以及线圈功率等参数的调整都会造成钝化层刻蚀速率和硅基刻蚀速率的同时变化，使RIE-lag的变化趋势复杂化，而只改变钝化阶段的压力时，由于未影响硅基刻蚀速率，使得硅基刻蚀线在水平方向平移，RIE-lag的变化则更可控。研究结论对实际工程中的Bosch工艺优化具有重要意义。
Abstract：The Bosch process is seeing increasingly broad application in high-aspect-ratio etching, yet the reactive ion etching lag(RIE-lag) effect continues to constrain etching uniformity and achievable aspect ratios. This study utilizes a multi-scale simulation approach, coupling global, sheath, and feature-scale etching models, to simulate the Bosch process using SF6 and C_4F8 gases under high-aspect-ratio conditions. It investigates the impact of key discharge parameters on the RIE-lag phenomenon. Findings reveal that both bias power and frequency influence RIE-lag primarily through modifications to the ion energy angular distribution(IEAD). An increase in ion energy from a low baseline enhances ion density at the etch front, initially improving RIE-lag; however, beyond a critical energy threshold, the RIE-lag effect worsens. Coil power directly modulates the plasma density, thereby altering the RIE-lag, which exhibits a non-monotonic trend —first decreasing and then increasing —with rising power.Increasing the pressure during the passivation step extends the time required to clear the passivation layer,which in turn improves RIE-lag performance. Analysis of the etch depth progression within the Bosch cycle timing shows that parameters such as bias power, bias frequency, and coil power concurrently affect the etch rates of both the passivation layer and the silicon substrate, leading to complex variations in RIE-lag. In contrast, adjusting only the passivation phase pressure leaves the silicon etch rate largely unchanged, resulting in a horizontal shift of the etch line and offering a more controllable means of influencing RIE-lag. These insights hold significant value for the optimization of the Bosch process in practical engineering applications.
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基本信息:
DOI：10.13922/j.cnki.cjvst.202510003
中图分类号:TN305.7
引用信息:
[1]龙思宇,曹世程,陈志华,等.Bosch放电参数对RIE-lag的影响研究[J].真空科学与技术学报,2026,46(02):125-135.DOI:10.13922/j.cnki.cjvst.202510003.
2025-12-18
2025-12-18
2025-12-18