Full field and full tensor stress metrology for flexible electronics, packaging, and optoelectronic applications: AM: Advanced metrology

Abstract

We describe the system for measurement of the stress tensor in polyimide (PI) substrates for flexible electronic application. System uses photo-elastic effects and was used for measurement of real life PI coated with conductive layers used for optoelectronic applications and reference bare substrates. Tool allows measurements with resolution better than 1 MPa, and covers entire range up-to mechanical failure of PI films. And can be readily integrated in roll to roll applications. The same tool gives promise to be used for the metrology of stress in other materials such as SiN, and use in mainstream semiconductor manufacturing when used on backend passivation PI films.