硅各向异性浅槽腐蚀实验研究

The Experimental Study on Anisotropic Etching of Silicon Shallow Trends

通过实验分析,对比了异丙醇(IPA)和超声波对Si(100)面在KOH溶液和四甲基氢氧化氨(TMAH)溶液中的浅槽腐蚀速率及其表面形态的影响。实验结果表明,IPA能降低TMAH溶液的腐蚀速率,但IPA在KOH溶液中腐蚀速率降低不明显;IPA加入到较高浓度的KOH溶液中,会在Si表面产生较大小丘,恶化了Si腐蚀表面的质量,但在TMAH溶液中加入一定量的IPA会改善腐蚀表面的质量;超声波能加快腐蚀速率并能改善Si腐蚀表面质量,但对于加入IPA的较高浓度KOH溶液,超声波未能消除Si腐蚀表面的小丘,另外,超声波还能减弱腐蚀过程中微尺寸沟槽的尺寸效应;在腐蚀条件和配比一定情况下,TMAH溶液的腐蚀质量比KOH溶液好。

The effects of IPA and ultrasonic agitation in KOH and TMAH solutions on the etch rate and surface roughness of （100） Si shallow trends were analyzed experimentally. The results showed that IPA additive which was used in TMAH solution slowed down the etch rate of Si obviously. But in KOH solution,IPA did not significantly affect the etch rate. Adding IPA to the solution with higher KOH concentration made the surface roughness of Si worse. Otherwise, IPA additive in TMAH solution improved the surface roughness of Si. The use of ultrasonic agitation in the two solutions mentioned above increased the etch rate and improved the surface roughness of Si. But in the solution of higher KOH concentration with IPA additive, the ultrasonic agitation didn＇t improve the surface roughness of Si. Additionally,the ultrasonic agitation weakened the size effect of micro-trend etching. Comparing with KOH solution,TMAH solution was preferable in silicon anisotropic etching.