硅深槽ICP刻蚀中刻蚀条件对形貌的影响

Effects of Technical Parameters on Etching Rate and Selectivity of Si Deep Trench Using ICP Etching

以SF6/C2H4为刻蚀气体,使用Corial200IL感应耦合等离子体(ICP)刻蚀系统,进行Si等离子刻蚀技术研究。通过调节刻蚀气体SF6与侧壁钝化保护气体C2H4的流量比和绝对值等工艺参数,对深Si刻蚀的形貌以及侧壁钻蚀情况进行改善,使该设备能够满足深硅刻蚀的基本要求,解决MEMS工艺及TSV工艺中的深硅刻蚀问题。实验结果表明,Corial200IL系统用SF6作等离子体刻蚀气体,对Si的刻蚀具有各向同性;C2H4作钝化气体,能够对刻蚀侧壁进行有效的保护,但由于C2H4的含量直接影响刻蚀速率和选择比,需对其含量及配比严格控制。研究结果为:SF6含量为40sccm、C2H4含量为15sccm时能够有效控制侧壁钻蚀,且具有较大的选择比,初步满足深硅槽刻蚀的条件。

Single crystal P-type silicon was etched with inductively coupled plasma （ICP） in SF6 ＋C2H4 gas mixture. The influence of process conditions, such as reaction gas flow, SF6/C2H4 ratio, and ICP power, on the etching morphology and the etching rate were discussed. Experiment results showed that Si plasma etching with SF6 exhibited isotropy. In order to obtain ideal etching patterning, appropriate content of C2H4 gas should be used. Meanwhile, the ratio of these two gases should be controlled exactly to satisfy the etching rate and the selectivity of deep silicon etching. With Corial 200IL system, the optimum condition is SF6 with 40 sccm and C2H4 with 15 sccm.