Palladium-assisted Metal Patterning on Polyimide Surfaces

摘要

A novel method of patterning high precision copper conductive micropatterns on flexible polymer substrate(polyimide)is developed.We utilized the coordination effect between palladium salts and pyridine structures to fix the palladium chloride(PdCl_(2))on the surface of polymer film while the 2,6-dimethylpyridine structures formed in the specific areas under ultraviolet light guaranteed the resolution of final patterns.Simultaneous thermal reduction of PdCl_(2) on the surface can be achieved in the process of thermal cyclization of the polymer substrate.As a consequence,the obtained polyimide(PI)film can be patterned with conductive copper micropatterns directly by electroless plating.In particular,we accomplished the deposition of high precision copper pattern with a minimum line width of 50μm and minimum line spacing of 20μm on PI thin films(thickness~10μm)by electroless plating.The prepared conductive copper micropatterns exhibit a low resistivity of 1.78μΩ·cm the same as the pure block copper.And the relationship between the structures of the polymer chains and the physical properties of polymer substrates,such as the dimensional stability,mechanical and dielectric properties were also discussed in detail.This simple and novel method of patterning metal on the polymer surface does not need to achieve the catalytic metal adhesion required for electroless plating at the cost of destroying the substrate surface and avoiding the introduction of unstable interlayers.This patterning method is compatible with the current roll-to-roll production process and can be used to develop high-performance micro-integrated circuits.