Cu on Polyimide Films by Vacuum Web Sputtering System for Tape Carrier Package

摘要

Adhesive copper on polyimide films have been widely adopted in the production of flexible circuits, rigid-flex substrates, chip scale packages and HDI products. In order to make direct bonded flexible copper clad laminate for semiconductor interconnector, we deposited tie (bond) and copper seed layer by DC pulse magnetron sputtering and electrodeposition of copper foil manufacturing for circuit formation after surface modification on polyimide film (Kapton-E and Uplix-S) by low energy ion beam processing. In this paper we discuss a new vacuum web coating system for surface modification of PI films using very low energy ion beam treatment with various gases. Also, film uniformity in thickness, adhesion strength, thermal stability of Cu foils on PI after electrodeposition of 9μm were investigated by thickness resistance measurement system, peel strength tester, and thermal curing. As the result, the peel strength was attained higher than 0.8 kgf/cm and kept 0.65 kgf/cm after thermal treatment for seven days at 150℃. Additional characteristics, including chemical endurance etching properties, flexural strength, and other practical examples for high-density circuits will be discussed.