SiC Trench Technology
Introduction
From a macro perspective, the new generation of technologies and applications represented by AI and electric vehicles will inevitably exert tremendous pressure on the global energy supply. In the long run, "energy constraints" will inevitably become a key factor restricting the development of advanced technologies and their penetration into the field, leading to a huge demand to reshape the entire energy system structure.
As a wide bandgap material, SiC naturally has a higher voltage resistance. Compared with traditional Si-based devices, power devices made of it can handle high-voltage currents at higher frequencies and in a wider temperature range. At the module level, it can significantly reduce losses, weight and volume. SiC also has a longer-term roadmap. All of these make SiC materials extremely advantageous in future energy technology changes.
工艺概述
等离子切割是一种非接触式的干法刻蚀技术，通过将气体（如SF₆、Cl₂、Ar等）等离子化，生成高能离子和自由基，与SiC材料发生物理和化学反应，从而实现材料的精准去除。该技术尤其适用于高硬度、高脆性的材料（如SiC），能够显著降低机械损伤和材料损耗。
ICP在SiC等离子切割中的核心作用
1.高密度等离子体生成ICP通过感应线圈产生高密度等离子体，其特点是等离子体密度高、能量分布均匀。这种特性使得ICP在SiC切割中能够实现高速刻蚀。
3.各向异性刻蚀控制ICP工艺可通过调节射频功率、气体流量和反应室压力等参数，精确控制刻蚀方向，减少横向刻蚀，从而形成垂直的切割侧壁。这对高深宽比结构的切割至关重要。
5.低损伤与高表面质量相较于机械切割或激光切割，ICP等离子切割的热影响区极小，几乎无裂纹和崩边现象。例如，实验数据显示SiC表面均方根粗糙度可低至1.2 nm。
工艺参数优化与技术
1.气体选择与混合比
◦Cl₂+Ar混合气体是常用组合，Cl₂提供化学刻蚀活性，Ar通过物理轰击增强材料去除效率。
◦SF₆等其他气体也可用于特定场景，需根据切割深度和表面质量要求调整。
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2.射频功率与压力控制
◦高射频功率（如ICP功率500 -2000 W）可提升等离子体密度和刻蚀速率，但需平衡热损伤风险。
◦低反应室压力（如<10 mTorr）有助于提高各向异性，但可能降低刻蚀均匀性。
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3.掩膜与图形化技术在切割前需通过光刻工艺定义切割道，使用抗蚀剂或硬掩膜
（如SiO₂）保护非切割区域，确保切割精度。