A New Approach for Developing a 3-D Stress Sensing Rosette Featuring Strain Engineering

Stress transducers play essential roles in diagnostic testing, monitoring, and nondestructive evaluation of many infrastructures. Particularly, 3-D piezoresistive (PR)-based stress sensors would tool up these applications with a high gauge sensing platform. In this article, strain engineering is utilized to develop a 3-D stress sensor where the microfabrication complexity and cost are reduced. Three types of prestrain are exploited for generating three different groups of PR coefficients; thus, a set of linear independent equations is obtained. The independency of these generated equations is verified both analytically and experimentally. A four-point testing is conducted on both chip wafer and flip chip on printed circuit board (PCB) structure to assess experimentally the capability of the strain approach to build a 3-D single polarity rosette. Both the analytical and experimental evaluations show the ability of the developed chip to extract the six stress components in a fully temperature compensation manner.