| 摘要 |
PURPOSE:To easily obtain a multilayer wiring board of high reliability at a low cost by a method wherein a specific polyimide precursor is use, and a fine opening pattern is formed through a specific patterning method and a wet etching method. CONSTITUTION:A first conductive layer is formed on a multilayered alumina ceramic board which contains a power supply and a grounding layer. A polyimide precursor solution of moisture permeability is applied onto the obtained board, which is pre-baked to form a polyimide precursor film. Then, a negative type photoresist is applied onto the polyimide precursor film, which is baked, then selectively exposed to light, and developed to form a prescribed pattern. The board is processed with an etching solution mainly composed of 40-90% by weight of aprotic magnetic solvent and 60-10% by weight of alcohol using the patterned negative type photoresist as a mask to form an opening pattern of prescribed shape. By this setup, a photoresist can be protected against cracks and separation. |
