Jiao Qingbin, Tan Xin, Zhu Jiwei, Feng Shulong, Gao Jianxiang
Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Nanhu Road, Changchun 130033, Jilin, China.
Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Nanhu Road, Changchun 130033, Jilin, China.
Ultrason Sonochem. 2016 Jul;31:222-6. doi: 10.1016/j.ultsonch.2015.12.019. Epub 2015 Dec 29.
In the silicon wet etching process, the "pseudo-mask" formed by the hydrogen bubbles generated during the etching process is the reason causing high surface roughness and poor surface quality. Based upon the ultrasonic mechanical effect and wettability enhanced by isopropyl alcohol (IPA), ultrasonic agitation and IPA were used to improve surface quality of Si (111) crystal plane during silicon wet etching process. The surface roughness Rq is smaller than 15 nm when using ultrasonic agitation and Rq is smaller than 7 nm when using IPA. When the range of IPA concentration (mass fraction, wt%) is 5-20%, the ultrasonic frequency is 100 kHz and the ultrasound intensity is 30-50 W/L, the surface roughness Rq is smaller than 2 nm when combining ultrasonic agitation and IPA. The surface roughness Rq is equal to 1 nm when the mass fraction of IPA, ultrasound intensity and the ultrasonic frequency is 20%, 50 W and 100 kHz respectively. The experimental results indicated that the combination of ultrasonic agitation and IPA could obtain a lower surface roughness of Si (111) crystal plane in silicon wet etching process.
在硅湿法蚀刻工艺中，蚀刻过程中产生的氢气泡形成的“伪掩膜”是导致表面粗糙度高和表面质量差的原因。基于异丙醇（IPA）增强的超声机械效应和润湿性，在硅湿法蚀刻过程中使用超声搅拌和IPA来改善Si（111）晶面的表面质量。使用超声搅拌时表面粗糙度Rq小于15nm，使用IPA时Rq小于7nm。当IPA浓度范围（质量分数，wt%）为5-20%，超声频率为100kHz且超声强度为30-50W/L时，超声搅拌和IPA结合使用时表面粗糙度Rq小于2nm。当IPA的质量分数、超声强度和超声频率分别为20%、50W和100kHz时，表面粗糙度Rq等于1nm。实验结果表明，超声搅拌和IPA的结合可以在硅湿法蚀刻过程中获得较低的Si（111）晶面表面粗糙度。
