| 摘要 |
PURPOSE:To obtain a circuit board which has excellent corrosion resistance against halogen ions and can hole excellent adhesive properties even if it is etched by composing a close contact layer in a wiring pattern of mixture of chromium and tungsten. CONSTITUTION:Mixture of chromium and tungsten, mixture of copper, chromium and tungsten are sequentially laminated on a board 15. A wiring layer 19 made of a close contact layer 16 of mixture of chromium and tungsten, copper 17 and a close contact layer 18 of mixture of chromium and tungsten is formed by etching. Further, polyimide 20 is formed as an insulating layer. Thus, even if it is soldered, it is not corroded with halogen ions in soldering flux to improve its reliability. |
