Published online by Cambridge University Press: 26 February 2011
This paper reports on the refinement of a mechanical model for theload-deflection of multilayer membranes under uniform differential pressureand on its application to the experimental extraction of materialparameters. Going beyond previous results, the analytical model takes intoaccount the mechanics of multilayers and elastic supports covering all casesbetween rigidly clamped to simply supported structures and enables thestraightforward assessment of stress profiles within the deformedstructures. A comprehensive set of long membranes made of variousmultilayers of silicon nitride and oxide films are fabricated andcharacterized. The out-of-plane deflection profile under pressure load ismonitored by means of a laser profilometer. The pressure is stepped up untilfracture occurs. From the stress profiles in the membrane at fracture, thebrittle material strength is analyzed using Weibull statistics. The bulgesetup has been fully automated for the measurement of 80 membranes perwafer. This realizes, for the first time, the high throughput-acquisition ofmechanical thin film data with convincing statistical control.