Predicting fracture in micron-scale polycrystalline silicon MEMS structures.

Hazra, Siddharth S. (Carnegie Mellon University, Pittsburgh, PA) ; de Boer, Maarten Pieter (Carnegie Mellon University, Pittsburgh, PA) ; Boyce, Brad Lee ; Ohlhausen, James Anthony ; Foulk, James W., III ; Reedy, Earl David, Jr.

Sandia National Laboratories

关键词: Tensile Properties;    Polycrystalline;    Cracks;    Microelectronic Circuits;    42 Engineering;   

DOI  :  10.2172/990954
RP-ID  :  SAND2010-6701
RP-ID  :  AC04-94AL85000
RP-ID  :  990954

美国|英语

来源: UNT Digital Library

【 摘 要 】

Designing reliable MEMS structures presents numerous challenges. Polycrystalline silicon fractures in a brittle manner with considerable variability in measured strength. Furthermore, it is not clear how to use a measured tensile strength distribution to predict the strength of a complex MEMS structure. To address such issues, two recently developed high throughput MEMS tensile test techniques have been used to measure strength distribution tails. The measured tensile strength distributions enable the definition of a threshold strength as well as an inferred maximum flaw size. The nature of strength-controlling flaws has been identified and sources of the observed variation in strength investigated. A double edge-notched specimen geometry was also tested to study the effect of a severe, micron-scale stress concentration on the measured strength distribution. Strength-based, Weibull-based, and fracture mechanics-based failure analyses were performed and compared with the experimental results.