Improving adhesion between thin chromium film and polyimide substrate by Ar+ irradiation

Improving Wettability of PoIyMethylMetiiAcrylate by Ar+ ion Irradiation in Oxygen Environment

Ion irradiation has been carried out to improve wettability of PMMA to water. The polymer was irradiated by argon and oxygen ions, and amount of ions was changed from 1014 ArVcm2 to 5xl016Ar+/cm2. Ions energies were varied from 0.5 keV to 1.5 keV, and oxygen gas was flowed from 0 seem to 6 scan near the polymer surface during ion irradiation. Wetting angle was reduced from 68 degree to 49 degree with increasing Ar+ ion irradiation, to 43 degree with Ch+ ion irradiation, and dropped to 8 degree with Ar+ ion irradiation with flowing 4 seem oxygen gas near the polymer surface. Recovery of wettability in dry air condition, and maintenance of it in dilute HC1 solution were explained in a view of formation of hydrophilic groups due to a reaction between irradiated polymer chain by energetic ion irradiation and flowing oxygen near the surface. Reactions among polymer matrix, energetic ions and oxygen gas to form hydrophilic group by energetic ions were discussed in terms of a two-step reaction, in which the first step is the creation of an unstable polymer chain by the ion irradiation and the second step is a reaction between the radicals and the oxygen gas.

Enhancement of Adhesion Between Cu Thin Film and Polyimide Modified by Ion Assisted Reaction

Polyimide films are modified by ion assisted reaction method using various ion beams in various gases environments. Amount of ion and blown gases rate were changed from 5 × 1014 to 1 × 1017 and from 0 to 8 sccm, respectively. Wetting angles between water and polyimide films modified by Ar+ ion without oxygen blowing decrease from 67° to 400° and surface free energies increase from 46 to 64 dyne/cm2. Wetting angle of polyimide films modified by Ar+ ion in an oxygen environment decreases to 12° and surface free energy increases to 72 dyne/cm2. The lowest wetting angle was obtained by oxygen ion irradiation in the oxygen gas environment and its value was 7°. In the case of polyimide film modified by Ar+ ions in an oxygen environment, the wetting angle increases up to 65° when it kept in air and that increases up to 46° when it kept in water after 5 day. In the case of polyimide film modified by O2+ ion in oxygen environment, however, the wetting angle of polyimide film dose not increase. X-ray photoelectron analysis shows that the chemical bonds between polyimide components are severed by ion irradiation and hydrophilic groups such as CO and C=O are formed by the reaction between newly formed radicals and blown oxygen. It was found that adhesion between Cu and polyimide modified by ion assisted reaction was improved. The main reason of the enhanced adhesion is due to the reaction between Cu and C-O or C=O groups formed by ion assisted reaction on the polyimide surface.