Diffusion simulations of gettering of ion implanted copper in polyimide

Gettering of ion-implanted copper in polyimide films was observed. The gettering process can be modeled by dual activation energies. The lower activation energy (small diffusant/substrate interaction) is associated with diffusants having no other diffusant atoms within their interaction distance, while a larger activation energy (large diffusant/diffusant interaction) represents diffusants with their movements restricted by clustering within the interaction distance of similar species. The gettering process is investigated through computer simulations of diffusion where the copper-copper interaction is included in the diffusion model, thus allowing copper atoms to be trapped by other atoms/clusters within the interaction distance. Simulation results validate the gettering process under these above assumptions and reveal several interesting dependencies of the process itself upon the initial implant profiles and doses