In this work a blister test is applied to study the adhesion of thin films to substrates. In the blister test one injects a fluid at constant rate at the interface between the substrate and an overlayer to create a “blister”. The fluid pressure is measured as function of time. An analysis gives a reliable way of calculating the adhesion energy Ga. from the time-dependent pressure data. The method was applied to a variety of systems including polymer/polymer, polymer/silicon and polymer/metal interfaces. The results show that the test is very sensitive and is able to determine small adhesion energies inaccessible in conventional peel tests. This work demonstrates that the blister test provides a means of relating the mechanical strength of an interface to its microscopic dynamic and structural features.

Fracture energy (Ga) of BPDA-PDA polyimide (PI) on modified and unmodified Si surfaces was measured by the “blister” test as a function of final cure temperature. It is proven quantitatively that surface modification prior to thin film deposition enhances adhesion. Metal adhesion to PI was also measured by the same method. Reproducibility of the data was found to be exceptionally good for both cases. The linear elastic model is quite valid for the test of thin film adhesion. Therefore, it is believed that this test is best suited for Ga measurements in the study of thin film adhesion for microelectronic packaging.