Island blister test

Recently, there have been reported several developments of the common blister test method." These include the island-blister test and the inverted-blister test developed by Fernando and Kinloch. Both of these test methods are designed to enable the adhesive fracture energy to be measured for a coating of thin adhered film where the coating or film has insufficient strength to resist the pressure needed for debonding if the standard blister test was employed. Wan and Mai have described a blister test in which the crack is driven by the expansion of a fixed mass of gas and stable growth ensues. ... 

According to the final use, there exist different methods to measure the adhesive strength of polymeric materials. The island blister test and 90° peel test are particularly suited to determine the level of adhesion of very thin films in electronic applications. In the case of structural adhesives, the lap shear strength of three- or multiple-layer structures is a typical standard. 

Figure 28 In the island blister test, the values of the diameters of the coating adhering part 2a 1 and suspended membrane 2a2 are measured as a function of the pressure p necessary to...

Other than the standard or the inverted blister test, the island blister test (Allen and Senturia 1989), the peninsula blister test (Dillard and Bao 1991), and the constrained blister test (Chang et al. 1989) have been proposed (Lacombe 2006). These tests are schematically shown in O Fig. 22.3. In the island blister test, a small inner island induces larger driving force for the propagation of the delamination front than that on the periphery (the crack initiation point for the standard blister test), which results in effective demationation at the interface between the film and the substrate. The peninsula blister test is a modification of the island blister test and improves the stability of the delamination. In the constrained blister test, a transparent rigid cover plate prevents the film from bursting while the observation of the delamination front is possible. For theoretical treatment of some of these tests, refer to the documents by Williams (1997). 

Geometry of (a) the island blister test, (b) the peninsula blister test, and (c) the constrained blister test. In the left and the right column, top view of the bottom substrate and the side view are described, respectively... 

Allen MG, Senturia SD (1989) Application of the island blister test for thin film adhesion measurement. I Adhes 29(1-4) 219... 

As stated earlier, adhesion is a major concern in electronic applications involving thin polyimide films either coated on hard substrates or laminated with metal ribbons. In these cases, neither lap-shear nor die-shear techniques allow the determination of the adhesion strength this can be done by using either the 90° peel test or the island blister test whose principles are sketched in Figs 12.26 and 12.27. The 90° peel test provides reliable data for the measurement of practical adhesion, especially useful for comparing the effect of surface treatments on the interfacial adhesion. The standard peel test procedure has been modified to determine the adhesive strength of thin polyimide films coated onto 10-cm silicon wafers. The equipment illustrated in Fig. 12.26 maintains a 90° peel effort during the test conducted at room temperature with a constant rate of crosshead displacement of 2 mm min . ... 

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