Adhesion strength of polyimide/Cr interfaces was measured using T-peel test on polyimide/Cr/Cu structures fabricated on BPDA-PDA polyimide, and correlation between adhesion strength and peeling angle has been investigated. Adhesion strength of BPDA-PDA/Cr interface decreased with increasing the thickness of Cr/Cu metal films to a critical value, and then increased with further increasing metal film thickness. When the thickness of Cr/Cu metal films was below a critical value, plastic bending of metal films mainly occurred during T-peel test. With metal films thicker than a critical thickness, however, plastic bending of polyimide film has been observed. A critical thickness of metal film, where transition from metal bending to polyimide bending occured, became thinner with decreasing the yield strength of metal film and increasing thickness of polyimide substrate. Without depending on the plastic bending of metal film or polyimide substrate, adhesion strength increased with increasing the peeling angle during T-peel test.