A Lamination Technique of LCP/CU for Electronic Packaging

LCP is expected to be used for the lamination of electronic circuit board because of its excellent mechanical and electric properties, such as a low dielectric constant and dimensional stability. However, it has not been widely used yet due to the weak interaction between LCP and $Cu$. Roughened surfaces of $Cu$ foil that could deteriorate the electrical property are being used in conventional lamination process in order to improve the bonding strength. Surface activated bonding (SAB) of Cu/LCP based on a surface cleaning process by physical bombardment in vacuum has been performed to achieve the strong bonding. A peel strength of 800~900glcm of the laminate prepared by SAB process is achieved, and the surface roughness of the interface between LCP and $Cu$ is controlled to be less than 100nm. In this experiment, additional treatment including Cu-deposition on LCP and annealing after bonding is applied in order to obtain strong bonding. The effects of these treatments are investigated with the discussion of bonding mechanism.