A single-side microcavity-diaphragm-channel one-step formation method for low-cost and high-yield volume production of micro flow sensors

作者：Song, Fang; Wang, Jiachou^*

来源：Microelectronic Engineering, 2015, 139: 1-6.

DOI：10.1016/j.mee.2015.04.074

• Microcavity-diaphragm-channel one-step formation
• IC-foundry-compatible fabrication
• Piezoresistor
• Differential pressure flow sensor

A novel low-cost and high-yield fabrication method for piezoresistor-based micro flow sensor is presented and developed. The IC-foundry-compatible microcavity-diaphragm-channel one-step formation process is implemented only from the front-side of a single (1 1 1) silicon wafer to facilitate the micro flow sensor directly packaged into microfluidic systems with low cost surface mounting technology (SMT). With only one lithographic mask, this composite structure of the microcavity-diaphragm-channel is constructed by etching rows of microholes, coating the vertical microhole-sidewall, removing the coating at the microhole-bottom, defining the sacrificial gap and lateral underetch release along < 1 1 0 > and < 2 1 1 > orientations. Finally, the composite structure can be sealed by depositing low-stress polysilicon to refilling the microholes, without the need for double-sided micromachining process, Cavity-SOI process, and wafer bonding technique. Based on the microcavity-diaphragm-channel structure, the micro flow sensor is fabricated and the performance is measured, exhibiting a sensitivity of 12.9 mV (mu L/min)(-1) for a 0-6 mu L min(-1) measured range (under DC 5-V supply), non-linearity of about +/- 0.2% FS, and the flow rate resolution better than 45 nl min(-1). In addition to the advantages of the high-performance and low cost batch-fabrication, the microcavity-diaphragm-channel one-step formation process can be widely used to fabricate many other MEMS-based microfluidic structure.

• 出版日期2015-5-1
• 单位哈尔滨工业大学; 中国科学院上海微系统与信息技术研究所; 机器人技术与系统国家重点实验室; 上海工程技术大学; 传感技术国家重点实验室