| AVS 61st International Symposium & Exhibition | |
| Surface Science | Tuesday Sessions |
| Session SS-TuP |
| Session: | Surface Science Poster Session |
| Presenter: | Ryosuke Tan, Kogakuin University, Japan |
| Authors: | R. Tan, Kogakuin University, Japan I. Takano, Kogakuin University, Japan |
| Correspondent: | Click to Email |
Recently, biodegradable resin attracts attention as one of the effective use of resources on environmental measures. PGA (Polyglycolic acid) used in this study is categorized to a kind of polyester resin and is composed of hydrogen, carbon and oxygen. PGA shows a high gas barrier property, a high hydrolysis property and high mechanical strength. These characteristics are applied for sutures of surgery or multi-layer PET bottles, while there is hardly application in an electronic field. The usage of PGA in electronic parts such as a printed circuit board has the important role in environmental measures, however there are some problems that have to be overcome.
In this study, the surface of PGA was modified by using an ion beam so that the durability of the PGA coated with metal films was improved. The ion beam cut off the bonding of molecules and as a result the surface of PGA turned to a carbon layer which was stable against heating or humidity. Double layer films of Cu/Ti were deposited on the modified PGA by vacuum evaporation. The Ti layer between the Cu film and the modified PGA (carbon layer) improved adhesion and electrical conductivity. The ion beam irradiation and vacuum evaporation were performed using the high current ion implanter with an electron beam evaporator. The ion beam was extracted from the bucket- type ion source with multi-aperture electrodes of 100 mm in diameter.
The Ar+ ion irradiation conditions were controlled at a current density of 20 μA/cm2, an acceleration voltage of 1 kV and irradiation time of 50 s. The deposition conditions of Ti were kept at a deposition rate of 0.3 nm/s and were changed a film thickness of 0-200 nm. The deposition conditions of Cu were kept at a deposition rate of 0.3 nm/s and a film thickness of 200 nm. The kind of prepared samples was the metal coated PGA sample, the ion irradiated PGA sample and the metal coated sample on the irradiated PGA. The sample hardness was measured by a load-unloading method using a micro-hardness tester with a Knoop indenter. Electrical conductivity of metal films was calculated from V-I characteristics measured using the four probe method. A surface chemical-bonding state was investigated by X-ray photoelectron spectroscopy.
The Ti layer between the Cu film and the carbon layer improved adhesion and electrical conductivity of samples. Those properties showed the maximum value at 50 nm in a Ti thickness, while the excess Ti-layer thickness decreased those properties. The measurement results of electrical conductivity suggested the possibility of PGA used as a printed circuit board.