Zero-Balance Method for Evaluation of Sealed Cavity Pressure Down to Single Digit Pa Using Thin Silicon Diaphragm
Zero-Balance Method for Evaluation of Sealed Cavity Pressure Down to Single Digit Pa Using Thin Silicon Diaphragm
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DOI：
10.1109/jmems.2020.2984229
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发表时间：
2020-06-01
影响因子：
2.7
通讯作者：
Tanaka, Shuji
中科院分区：
文献类型：
--
作者：
Al Farisi, Muhammad Salman;Hirano, Hideki;Tanaka, Shuji
微封装的密封腔压力往往成为决定封装微机电系统（MEMS）性能的因素。本研究针对一种使用薄膜片的微封装，对密封腔压力评估方法进行了全面的研究。当分隔两个容积的隔膜变平时，密封腔压力与周围压力相同，即零平衡法。零平衡法在制造工艺简单和压力评估范围方面具有其他技术的优势。介绍了两种方法来减少残余应力的影响，这通常存在于传统使用的绝缘体上硅（SOI）膜片。应力补偿层的引入能够降低SOI基膜片的残余应力的影响。然而，在膜片上产生显著的滞后，这限制了密封腔的精确测量。另一方面，通过碱湿法腐蚀产生的掺硼硅薄膜，可以避免残余应力。使用这样的隔膜，可以以一位数Pa的精度测量几Pa的密封腔压力。[2020-0014]
The sealed cavity pressure of a micro-package often becomes the determining factor of the performance of an encapsulated micro-electro mechanical system (MEMS). In this study, a sealed cavity pressure evaluation method for a micro-package using a thin diaphragm is studied comprehensively. The sealed cavity pressure is identical to the surrounding pressure when the diaphragm separating both volumes becomes flat, i.e. zero-balance method. The zero-balance method has advantages to other techniques in terms of fabrication process simplicity and pressure evaluation range. Two approaches are introduced to reduce the impact of the residual stress, which typically exists in the conventionally used silicon-on-insulator (SOI) diaphragm. The introduction of a stress compensation layer was able to reduce the impact of the residual stress of SOI-based diaphragms. However, a significant hysteresis is developed on the diaphragm, which limits the precise measurement of a sealed cavity. On the other hand the residual stress can be avoided by the usage of intentionally tensile stressed boron doped Si diaphragm, which is produced by alkaline wet etching. Using such a diaphragm, a sealed cavity pressure of several Pa can be measured with a single digit Pa accuracy. [2020-0014]