Fabrication of three-dimensional parylene HT diaphragms using D-RIE with a Si substrate
Fabrication of three-dimensional parylene HT diaphragms using D-RIE with a Si substrate
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DOI：
10.1016/j.sna.2016.11.021
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发表时间：
2017
影响因子：
4.6
通讯作者：
S. Imai
中科院分区：
文献类型：
--
作者：
S. Imai
这项工作演示了使用深反应离子蚀刻（D-RIE，或使用博世工艺的离子耦合等离子体蚀刻）制造具有三维结构的聚对二甲苯隔膜，并评估了所得产品的特性。由于 D-RIE 工艺中会产生大量热量，因此使用了具有高达 350 °C 优异耐温性的聚对二甲苯 HT。首先将聚对二甲苯沉积在硅基板上，并在该基板的背面蚀刻隔膜配置。与湿法蚀刻相比，D-RIE 能够制造具有精细投影的任何隔膜轮廓，从而可用于微机电系统 (MEMS)。生产平面隔膜是为了确定聚对二甲苯的耐热性，还制造了带有波纹矩形凹槽（30-50 μm 深）的隔膜（直径 5 毫米，10 μm 厚）。当深度为 50 μm 时，扫描电子显微镜 (SEM) 发现凹槽拐角处存在一些缺陷。通过将矩形角转变成圆形并在聚对二甲苯层上沉积铝，最终可以毫无缺陷地制造出这样的凹槽。人们发现有必要仔细评估拐角附近的热应力，并且该应力主要受凹槽深度的影响。 D-RIE 工艺后评估聚对二甲苯层的表面粗糙度和机械性能，包括杨氏模量和屈服应力。
This work demonstrates the fabrication of parylene diaphragms with three-dimensional configurations using deep-reactive ion etching (D-RIE, or ion-coupled plasma etching using the Bosch process) and assessed the characteristics of the resulting products. Parylene HT, which has superior temperature resistance up to 350 °C, was used due to the significant heat generated in the D-RIE process. Parylene was first deposited on a silicon substrate and a diaphragm configuration was etched on the backside of this substrate. In contrast to wet etching, D-RIE was able to fabricate any outline of diaphragms with fine projections, such that could be employed in a microelectromechanical system (MEMS). Planar diaphragms were produced to ascertain the heat resistance of the parylene, and diaphragms (5 mm in diameter, 10 μm thick) with corrugated rectangular grooves (30–50 μm deep) were also fabricated. Scanning electron microscopy (SEM) identified some defects in the corners of grooves when employing a depth of 50 μm. Such grooves were eventually fabricated without defects by converting the rectangular corners to rounded shapes and by depositing aluminum on the parylene layer. It was found to be necessary to carefully assess the thermal stress in the vicinities of corners, and that this stress was primarily affected by the groove depth. Surface roughness and mechanical properties of the parylene layers, including Young’s modulus and yield stress, were assessed after the D-RIE process.