超声技术在硅湿法腐蚀中的应用

Abstract

为了获得平滑的硅湿法腐蚀表面,在硅湿法腐蚀中引入超声技术。对超声湿法腐蚀系统进行了改进,以确保腐蚀溶液的顶部和底部温差在0.5℃之内。采用60℃,10%质量分数的kOH溶液,在超声频率为59 kHz,超声功率为60--180 W(间隔10 W)条件下对(100)硅片进行湿法腐蚀。最后,运用激光共聚焦扫描显微镜(lSCM)对腐蚀后硅片表面粗糙度进行测量,并探讨超声参数的选择对腐蚀表面质量的影响。实验结果表明:超声功率在120 W时,可以获得平滑的腐蚀表面,表面粗糙度rQ值为0.020μM。在湿法腐蚀系统中采用超声技术,可以明显改善腐蚀表面质量,在较低温度和较低浓度的kOH溶液中,选择合适的超声参数可获得高品质的腐蚀表面。

In order to achieve smooth wet etching surface of silicon,ultrasonic technology is introduced in the wet etching of silicon.By improving the ultrasonic wet etching system,the temperature difference between top and bottom etching solutions can reach 0.5℃.Then,at 60℃(100),silicon is etched wetlly by KOH solution in mass ratio of 10%, ultrasonic frequency of 59 kHz and ultrasonic power ranging from 60 W to 180 W(every 10 W).Finally,the post-etched surface roughness is measured by Laser Scanning Confocal Microscope(LSCM),and the effect of ultrasonic parameters on the quality of etching surface is discussed.Experimental results indicate that the smooth etching surface can be obtained in roughness Rq of 0.02 μm at ultrasonic power of 120 W.The quality of etching surface is greatly improved in the ultrasonic wet etching system,also the etching surface of high quality can be obtained with suitable ultrasonic parameters in lower temperature and concentration of KOH solution.