Organic/Inorganic Thin Film Multi-layer on Polymer Films for Rollable OLED

Presented by Jung Cho, Flex-e Materials

Copper foil without adhesive on polyimide films have been widely adopted in information technology such as production of flexible printed circuits, drive IC substrates for liquid crystal display and optical pickup for hard disk suspensions. Especially, substrates market for LCD and OLED are rapidly increasing with 35 ~ 40% every year and will be 2.5 billions $ in 2007. In order to make thinner layer pattern and higher thermal stabilized substrates, copper foil should be attached between copper and polyimide substrates without adhesives. For these applications, two kinds of flexible copper clad laminates (F-CCL) have been developed. One is casting type two layer F-CCL which polyimide varnish is coated on copper foil and cured on copper foil surfaces. The other is oppositely making of copper foil on polyimide films by using both vacuum sputtering and electroplating. In this paper, we deposit a thin tie layer (6.5~15 nm) and Cu seed layer (100~200 nm) on polyimide film (Kapton-EN and Upilex-S) after very low energy ion beam irradiation with various gases for the improvement of adhesion and thermal stability. After electroplating 9㎛ thick Cu foils on polyimide, the thickness uniformity, adhesion strength and a thermal stability of the FCCL are investigated by a x-ray thickness measurement, a 90o peel strength tester and thermal curing treatment. As the results, the peel strength of the as-received FCCL is higher than 0.8 kgf/cm and kept 0.65 kgf/cm even after thermal treatment 7 days at 150 oC and a 9 ㎛ thick FCCL shows a very good thickness uniformity with only ± 2.8% standard deviation over 520 mm in width.