巻取り式プラズマエッチングによるポリイミドへのビアホール加工 [in Japanese] Via Hole Formation in Polyimide Film by Plasma Etching Using a Roll Etcher System [in Japanese]
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The Build-up Process is very important in the production of a multilayer printed wiring board (PWB) in electric communication devices. Nowadays, laser and photolithography processes are the main methods used for forming via holes in the polyimide in the Build-up Process. In this study, as a preliminary experiment for via hole formation, etching rates in polyimides were investigated using a plasma etching process with a roll coater instead of previously utilized processes. This was carried out with a reactive ion etching (RIE) discharge, created by applying a low frequency power of 400 kHz to the main roller as a cathode, using O<SUB>2</SUB> and CF<SUB>4</SUB> gases. A high dynamic etching rate of 5 μm ·m/min was the target value. The dynamic etching rate increased with the power applied, and the maximum values obtained were 3 and 2 μm ·m/min for polyimide films (25 μm) of Kapton 100H and Upilex S, respectively. To realize a higher density of plasma, a high frequency power of 13.56 MHz was applied to the anode, from which the etching gasses were fed, in addition to the RIE discharge. The etching rate was found to further increase as a result. Moreover, adding N<SUB>2</SUB> gas to the etching gases increased the etching rate. These results taken together have created the possibility to surmount the target value.
Shinku 45(3), 165-168, 2002-03-20
The Vacuum Society of Japan