KrF excimer laser micromachining of MEMS materials: characterization and applications
KrF excimer laser micromachining of MEMS materials: characterization and applications
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DOI：
10.1088/0960-1317/22/1/015012
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发表时间：
2012-01-01
影响因子：
2.3
通讯作者：
Noh, Hongseok Moses
中科院分区：
文献类型：
--
作者：
Liu, Kewei;NiCkolov, Zhorro;Noh, Hongseok Moses
传统的基于光刻的微制造技术如今被广泛用于制造微尺度结构和器件。然而，这些技术仅限于二维制造以及特定的材料。准分子激光微加工使我们能够克服这些限制，并促进三维（3D）微细加工。本文提出了一个全面的表征研究准分子激光微加工的微机电系统（MEMS）材料。采用248 nm KrF准分子激光器，对4种典型的MEMS材料（Si、钠钙玻璃、SU-8光刻胶和聚二甲基硅氧烷）进行了激光烧蚀，得到了激光烧蚀参数（能量密度、频率和脉冲数）与刻蚀性能（垂直和横向刻蚀速率、深宽比和表面质量）之间的关系。对于所有四种材料，随着能量密度的增加，蚀刻速率几乎线性地增加，但是随着激光脉冲的频率的改变，没有观察到蚀刻速率的显著变化。蚀刻速率也与激光脉冲的数量成反比。使用SEM成像研究了PDMS和SU-8上激光加工位点的物理变形。为了证明准分子激光器的三维微加工能力和本表征研究的效用，两种新型的可植入生物医学微尺度器件制成的SU-8和PDMS成功地制造使用优化的激光烧蚀参数在本研究中获得。
Conventional photolithography-based microfabrication techniques are widely used to create microscale structures and devices nowadays. However, these techniques are limited to two-dimensional fabrication and also to particular materials. Excimer laser micromachining enables us to overcome those limitations and facilitates three-dimensional (3D) microfabrication. This paper presents a comprehensive characterization study for excimer laser micromachining of micro-electro-mechanical system (MEMS) materials. By using a 248 nm KrF excimer laser and four representative MEMS materials (Si, soda-lime glass, SU-8 photoresist and poly-dimethysiloxane (PDMS)), the relations between laser ablation parameters (fluence, frequency and number of laser pulses) and etch performance such as the etch rates in the vertical and lateral directions, aspect ratio, and surface quality were obtained. The etch rate increased almost linearly for all four materials as the fluence increased but no significant variation in etch rate was observed as the frequency of laser pulses was changed. The etch rate was also inversely proportional to the number of laser pulses. Physical deformation in the laser-machined sites on PDMS and SU-8 was investigated using SEM imaging. In order to demonstrate the 3D microfabrication capability of an excimer laser and the utility of this characterization study, two novel implantable biomedical microscale devices made of SU-8 and PDMS were successfully fabricated using the optimized laser ablation parameters obtained in this study.