表面微機械微小量程壓力傳感器采用多晶硅薄膜等有內應力的敏感膜片時,應力往往會
使膜片的力學靈敏度大大下降,無法滿足微量程測量的要求。波紋膜片可以消除或減小應力來提高靈敏度,但是其波紋結構本身又會造成力學靈敏度下降,從而部分抵消了應力消除的效果。提出一種新型深盆腔膜片結構,在消除應力的同時實現了比平膜片還高的力學靈敏度,可以提高微壓傳感器和微麥克風的靈敏度。采用解析和有限元兩種方法相結合的方法,對該種膜片進行了分析和研究。對比平膜和波紋膜結構,顯示了深盆腔膜在力學靈敏度方面的顯著提高。
關鍵詞:壓力膜片;微機械傳感器;力學靈敏度;薄膜殘余應力
Abstract :When thin - film with residual stress used for sensitive diaphragm of micromachined low - range pressure sensors ,mechanical sensitivity of the diapgragm is ,more often than not ,much lowered due to the stress. Currently ,corru2 gated diaphragm is used for stress release ,thereby ,improving the mechanical sensitivity. However ,corrugated diaphragm
itself is with a stiffened structure compared with conventional flat diaphragm that renders a lower mechanical sensitivity. Therefore ,There is a trade off when a corrugated diaphragm employed for pre - stressed diaphragm. A novel deep cavity - shaped diaphragm is proposed in this paper. The structure is capable of simultaneously releasing the stress and decreasing
mechanical stiffness. Analysis and finite element method (FEM) are combined to study the mechanical principles of the di2 aphragm. The results show that the proposed deep cavity - shaped structure is with much improved mechanical sensitivity , compared with conventional flat diaphragm and corrugated diaphragm.
Key Words :Pressure - sensitive Diaphragm;Micromachined Sensors ;Mechanical Sensitivity ;Residual Stress of Thin - film