Thick Layers’ Adhesion Measurements on Flexible Substrate by Cross Cut Adhesion Test

Flexible electronics is currently widely used to create new bendable and stretchable structures. Since these structures are mechanically stressed, it is necessary to know the adhesion between the layers, which shows their durability. In this paper, we propose and test a new cheap adhesion method which could substitute expensive methods. The adhesion was analyzed by cross cut adhesion test, which is typically used for measuring the adhesion of paints. The tested samples were fabricated by screen printing technology. Three types of flexible foils, polyimide (PI), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN) were used as a substrate. Three different types of polymer pastes were deposited on the substrates. Two pastes were based on silver particles and one on carbon particles. The test was performed by a special tool TQC CC 3000 specified by the ISO and ASTM standards. The samples were evaluated by the software “CCT Analyzer’' developed at the Department of Technologies in Electronics. The results show that the cross cut test is a cheap, fast, accurate method for measuring the adhesion of thick polymer layers and a suitable substitute for the expensive tests.