No abstract

Yield analysis of microsystems is increasingly becoming important due to their decreasing feature sizes. Despite many ways and methods for statistical yield analysis, the contribution of worstcase methods in the yield analysis of microsystems is significant. Worst-case methods, in general, offer advantages like reduced number of simulations and a quantifiable yield metric in yield analysis of a system. However, the common yield analysis problems in MEMS and other microsystems have been identified to be falling into the category of non-linear specification boundaries. In this paper we present an enhancement to the yield analysis of microsystems using worst-case methods. The enhancement has been achieved in terms of accuracy of the parametric yield calculation process by considering non-linear metamodels in place of linear main-effect models. A function suite (WCAS) has been developed in order to implement the worst-case analysis and compare the results of the pre and post enhancements. The demonstrator used for comparing the results of pre and post enhanced worst-case analysis was a U-Shaped thermal actuator.

The intricacy in the manufacturing of MEMS devices has resulted in decreasing parametric yields. The problem of reduced parametric yield is increasing with the waning feature sizes. The necessity for yield enhancement in MEMS designs and particularly in commercial MEMS is being increasingly felt by the industry and therefore by the designers. There has been no standard methodology that could be followed to enhance yield in the design phase. In this paper we undertake effort in order to standardize a best practice design method in order to achieve a better yield in the design phase. The method is still in its infancy and has good scope for development. The validity of the proposed method is demonstrated via a simulation based approach on a U-Shaped micro electro thermal actuator.

This paper presents an emerging theory on the effects of unavoidable process variations during the fabrication of MEMS and other microsystems. The effects of parametric variations on device performance and design yield of the microsystems devices are analyzed and presented. A novel methodology in the design cycle of MEMS and other microsystems is introduced. The methodology is based on the concept of worst-case analysis having colossal advantages to offer. This paper describes some steps of this methodology with elaborated results. Also described in this paper is how each step contributes to counteract the effects produced by the parametric variations in the product cycle of microsystems.