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2025, 07, v.62 29-36
用于薄膜体声波谐振器腔体释放的氟化氢气相刻蚀研究
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DOI: 10.13250/j.cnki.wndz.25070201
摘要:

氟化氢(HF)气相刻蚀是制备薄膜体声波谐振器(FBAR)空腔结构的关键工艺。利用HF气相刻蚀设备,使用HF、乙醇蒸气和氮气的混合气体对热氧化生长的2μm厚的SiO2牺牲层进行气相刻蚀实验,探究了刻蚀时间、气体流量、腔室压力和腔室温度等参数对HF气相刻蚀速率的影响。实验结果表明:提高腔室压力可以显著提升刻蚀速率,但发现释放后的FBAR工艺控制监控(PCM)空腔结构出现了粘连塌陷,腔体表面也出现了沉积点状副产物。当腔室压力达130 Torr(1 Torr≈133 Pa)时,采用高低压循环刻蚀(腔室压力130 Torr气相刻蚀9 min,腔室压力50 Torr气相刻蚀1 min),释放后的FBAR PCM空腔结构则未出现上述问题,HF气相刻蚀速率为1 350?/min(1?=0.1 nm),比初始HF气相刻蚀速率(330?/min)提高了约4.1倍。该方案已成功应用于FBAR芯片量产。

Abstract:

hydrogen fluoride(HF) vapor-phase etching is the critical process for preparing the cavity structure of film bulk acoustic resonator(FBAR). The mixture of HF, alcohol vapor and nitrogen gas was utilized to perform vapor-phase etching experiment on a 2 μm thick thermally oxidized SiO2 sacrificial layer by using HF vapor-phase etching equipment. The effects of parameters such as etching time, gas flow rate, chamber pressure and chamber temperature on the HF vapor-phase etching rate were explored. The experimental results show that the increase of the chamber pressure can significantly improve HF vapor-phase etching rate. However, it is found that adhesion collapse occurs in the released cavity structure of FBAR process control monitor(PCM), and punctiform by-product deposit appears on the surface of the cavity. When the chamber pressure is 130 Torr(1 Torr≈133 Pa), by using chamber high and low pressure cyclic etching(chamber pressure is 130 Torr for 9 min of vapor-phase etching and 50 Torr for 1 min of vapor-phase etching), the released FBAR PCM cavity structure have none of the above problems. The HF vapor-phase etching rate is 1 350 ?/min(1 ?=0.1 nm), which is about 4.1 times higher than the initial HF vapor-phase etching rate(330 ?/min). The scheme has been successfully applied to the mass production of FBAR chips.

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基本信息:

DOI:10.13250/j.cnki.wndz.25070201

中图分类号:TB383.2;TN65

引用信息:

[1]康建波,付越东,高渊等.用于薄膜体声波谐振器腔体释放的氟化氢气相刻蚀研究[J].微纳电子技术,2025,62(07):29-36.DOI:10.13250/j.cnki.wndz.25070201.

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