10%TMAH硅湿法腐蚀技术的研究

研究了浓度为10%的四甲基氢氧化铵(TMAH)溶液,在不同量的Si粉掺杂下,对铝膜及硅衬底的腐蚀及其pH值的变化。测试了在满足铝膜极低的腐蚀速率(<1nm/min)时,不同温度下该腐蚀液对硅(100)、(111)和(110)晶面及SiO2介质膜的腐蚀速率。还介绍了添加剂—过硫酸铵(APODS)和吡嗪的加入对腐蚀表面形貌及腐蚀速率的影响。研究结果表明,存在着一个临界的硅粉添加量,超过此量后铝膜的腐蚀速率急剧降低。90℃时,在10%TMAH溶液中加入1 5mol/L硅粉、3 0g/LAPODS和2g/L吡嗪可以实现铝膜不被腐蚀,同时硅(100)面约有1μm/min的腐蚀速率,腐蚀表面平整。腐蚀后的铝膜表面同硅铝丝键合良好,实现了腐蚀工艺同CMOS工艺的完全兼容。

Study on Si Wet-etch with 10% TMAH

Characterization of etching of Al film and Si substrate with 10% tetramethylammonium hydroxide (TMAH) has been done at a condition of adding various amount of Si dust.The etching rate of Si (100), (111) and (110) plane, as well as the etching rate of dielectric film SiO_2 are presented when low Al etching rate (<1nm/min) achieved.The influence of the additives-ammonium peroxydisulfate (APODS), and pyrazine on etching rate and etched surface morphology are also discussed.It is shown that Al etching rate drops rapidly when a critical amount of Si dust added.It is indicated that a CMOS-compatible etching with smooth etched surface and about 1 _m/min etching rate for Si (100) direction can be realized by adding 1.5 mol/L Si dust, 3.0 g/L APODS and 2 g/L pyrazine into 10% TMAH etchant.