石英玻璃刻蚀浅锥孔阵列的工艺研究

Process of Etching Shallow Tapered-Hole Arrays in Quartz Glass

摘要:

介绍了石英玻璃刻蚀浅锥孔的制备方法。通过紫外接触式光刻系统在石英玻璃上形成光刻胶浅锥孔阵列图案,用电感耦合反应离子刻蚀机(ICP-RIE)进行刻蚀。研究了光刻参数和蚀刻参数(气体流量、气体成分、腔压、ICP功率和偏置功率)对石英玻璃的刻蚀性能、表面轮廓、蚀刻速率和侧壁倾角的影响。结果表明:刻蚀气体种类对石英浅锥孔阵列刻蚀效果有显著影响,CF₄和Ar的组合气体所刻蚀的石英锥孔阵列的效果最佳,随着CF₄气体流量比的增加,石英刻蚀倾角先降低后又小幅增加,当刻蚀气体(CF₄∶Ar)流量比在5∶3时,石英刻蚀速率为0.154μm/min,光刻胶刻蚀速率为0.12μm/min,得到的石英浅锥孔倾角最倾斜。在其他刻蚀参数一定的情况下,ICP功率由600W升高至800W,石英刻蚀速率大幅降低,聚合物的沉积成为刻蚀工艺的主导；刻蚀石英的粗糙度R_q随着ICP功率的降低明显增加；RF功率升高时刻蚀石英的速率增加,R_q值增加后又降低,当RF功率升高至200W时,光刻胶发生碳化现象。可为石英玻璃微器件的制备提供工艺参考。

Abstract:

We herein introduce a method for preparing shallow-tapered holes etched on quartz glass. The effects of lithographic and etching parameters (gas flow, gas composition, cavity pressure, ICP power, and bias power) on the etching properties, surface profile, etching rate, and sidewall inclination of quartz glass were investigated. The results showed that the type of etching gas significantly affected the etching of the shallow cone-hole array on quartz and that the combination of CF₄ and Ar yielded the best etching effect. As the CF₄ gas flow rate increased, the quartz etching angle first decreased and then increased slightly. When the CF₄∶Ar gas flow ratio was 5∶3, the quartz etching rate was 0.154μm/min, the photoresist etching rate was 0.12μm/min, and the inclination of the shallow quartz cone hole was the highest. When other etching parameters were applied, the ICP power increased from 600 to 800W, the quartz etching rate decreased significantly, and polymer deposition became the dominant etching process. The roughness (R_q) of the etched quartz increased with decreasing ICP power. As the RF power increased, the rate of quartz etching increased, and the R_q value of the etched quartz first increased and then decreased. When the RF power was increased to 200W, photoresist carbonization occurred. This study provides a technical reference for the preparation of quartz-glass microdevices.