Fitzgerald Matthew L, Tsai Sara, Bellan Leon M, Sappington Rebecca, Xu Yaqiong, Li Deyu
Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
The Vanderbilt Eye Institute and Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
Biomed Microdevices. 2019 Mar 2;21(1):26. doi: 10.1007/s10544-019-0379-8.
Polydimethylsiloxane (PDMS) has been the pivotal materials for microfluidic technologies with tremendous amount of lab-on-a-chip devices made of PDMS microchannels. While molding-based soft-lithography approach has been extremely successful in preparing various PDMS constructs, some complex features have to been achieved through more complicated microfabrication techniques that involve dry etching of PDMS. Several recipes have been reported for reactive ion etching (RIE) of PDMS; however, the etch rates present large variations, even for the same etching recipe, which poses challenges in adopting this process for device fabrication. Through systematic characterization of the Young's modulus of PDMS films and RIE etch rate, we show that the etch rate is closely related to the polymer cross-link density in the PDMS with a higher etch rate for a lower PDMS Young's modulus. Our results could provide guidance to the fabrication of microfluidic devices involving dry etching of PDMS.
聚二甲基硅氧烷（PDMS）一直是微流控技术的关键材料，大量基于芯片实验室的设备都由PDMS微通道制成。虽然基于模塑的软光刻方法在制备各种PDMS结构方面极为成功，但一些复杂特征必须通过涉及PDMS干法蚀刻的更复杂微加工技术来实现。已经报道了几种用于PDMS反应离子蚀刻（RIE）的方法；然而，即使对于相同的蚀刻方法，蚀刻速率也存在很大差异，这给将此工艺应用于器件制造带来了挑战。通过对PDMS薄膜的杨氏模量和RIE蚀刻速率进行系统表征，我们表明蚀刻速率与PDMS中的聚合物交联密度密切相关，PDMS杨氏模量越低，蚀刻速率越高。我们的结果可为涉及PDMS干法蚀刻的微流控器件制造提供指导。
