Design of Multi-Span Microfixturing Cell for Parallel Assembly of Microparts Using Electrothermally Actuated Microclamps

Abstract

Many microparts including the parts used as MEMS components require assembly using parallel assembly techniques. MEMS packaging, including the Wafer Level method, is a prominent process that has been considerably investigated in recent years. In wafer level packaging, either an alignment template (AT) must have special receptor sites according to the micropart geometry and its material or the microcomponents should have additional features like circular and cross pegs for shape recognition stage. In this article, a modular AT which comprises of a microfixturing cell with electrothermal microclamps is presented for positioning and holding microcomponents for later processes like flip chip bonding. The microparts are distributed on the microfixture buffer on a rotary table. After that piezoelectric vibration is induced, stimulated microparts are trapped between the microclamp arms. Then electrical current is applied to create in-plane thermal expansion of the arms. Using this procedure, a micropart is positioned properly and trapped. The rotation of the table continues to lead other microparts to their own positions but the trapped microparts stay standstill. This method enjoys the advantage of omitting the receptor sites. Moreover, in conventional methods, these receptor sites should be designed according to the parts’ shapes and their materials. In this novel approach, not only identical clamps are used for diverse assembly configurations, but also the technique is capable of being used for different types of microcomponent materials. Just true positioning of the clamps provides required theme of assembly. Finite element analysis is used to simulate the whole procedure.