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]

中文翻译：

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使用薄硅膜片评估密封腔压力低至个位数 Pa 的零平衡方法

微封装的密封腔压力通常成为封装微机电系统 (MEMS) 性能的决定因素。本研究综合研究了一种采用薄膜隔膜的微封装密封腔压力评估方法。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性和压力评估范围方面优于其他技术。引入了两种方法来减少残余应力的影响，残余应力通常存在于传统使用的绝缘体上硅 (SOI) 隔膜中。应力补偿层的引入能够减少基于 SOI 的隔膜残余应力的影响。然而，隔膜上会产生明显的滞后现象，这限制了密封腔的精确测量。另一方面，通过使用碱性湿法蚀刻产生的有意拉伸应力的掺硼硅隔膜，可以避免残余应力。使用这样的隔膜，可以以一位数的 Pa 精度测量几 Pa 的密封腔压力。[2020-0014] 数 Pa 的密封腔压力可以以个位数 Pa 精度进行测量。[2020-0014] 数 Pa 的密封腔压力可以以个位数 Pa 精度进行测量。[2020-0014]