过硫酸铵在TMAH体硅刻蚀中的作用  

Effects of Ammonium Persulfate on Anisotropic Etching of Silicon in TMAH Solutions

作　　者：余协正[1] 叶迎华[1] 沈瑞琪[1] 李创新[2] 

机构地区：[1]南京理工大学应用化学系,南京210094 [2]武汉军械士官学校,武汉430075

出　　处：《微纳电子技术》2012年第2期134-139,共6页Micronanoelectronic Technology

摘　　要：为了提高低浓度下四甲基氢氧化铵(TMAH)体硅刻蚀的质量,通过对质量分数为5%的TMAH进行研究,发现合适的过硫酸铵(AP)添加方式和添加量能够在不降低刻蚀速率的条件下提高体硅刻蚀质量。通过SEM,EDS和XRD对AP的作用机理进行深入分析,发现加入AP能使刻蚀底面生成"伪掩膜",并确定其成分为低温石英晶体。这些"伪掩膜"能够选择性地覆盖于刻蚀底面金字塔小丘的交界区域,使刻蚀底面相对凹陷的部分被保护,而金字塔顶相对凸出的部分则被刻蚀,从而在宏观上达到了降低粗糙度的效果。在此基础上得到了"两步法"的优化刻蚀工艺,结合该工艺已成功制备出深度485μm,平均刻蚀速率1.01μm/min,底面粗糙度仅为0.278μm硅杯微结构。In order to improve the bulk silicon etching quality in low concentration of TMAH,TMAH with the mass fraction of 5% was studied,and it was found that the suitable additive amount and manner of ammonium persulfate（AP） can improve the etching quality without redu-cing the etching rate.The effects of AP in TMAH was further analysed by means of SEM,EDS and XRD,and the ＂pseudo-mask＂ generated on the etching surface,which was the quartz crystal at low temperature.The ＂pseudo-mask＂ selectively covered on the junction area between the pyramids on the etching bottom surface.It enables the recessed portion to be protected,while the convex part like the top of the pyramids was etched,thus the roughness was reduced from the macroscopic view.On this foundation,an optimized ＂two-step＂ etching process was obtained,which was successfully used to fabricate a silicon micro cup of 485 μm depth,0.278 μm surface roughness with the average etching rate of 1.01 μm/min.

关 键 词：微电子机械系统(MEMS) 四甲基氢氧化铵(TMAH) 各向异性刻蚀 过硫酸铵(AP) 粗糙度 

分 类 号：TH703[机械工程—仪器科学与技术] TN405[机械工程—精密仪器及机械]