| 摘要 |
<p>PURPOSE:To reduce resistance variation and enhance heat resistance by coating epoxy resin over printed resistors for the formation of an inner layer board, putting prepreg and outer layer copper foils on both sides of the inner layer board, and pressing the whole at a high temperature. CONSTITUTION:Conductor patterns and printed resistors are formed on a board, and epoxy resin is coated over the printed resistors to fabricate an inner layer board. On both sides of the over-coated inner layer board, prepreg and outer layer copper foils are overlaid to press them integrally at a high temperature under a reduced air pressure of less than 100Torr by applying a pressure of less than 50kgf/cm<2>. As an inner layer board, there can be used a copper clad laminated board usually employed as a printed circuit board, which is integrally formed by superposing a plurality of prepregs ordinarily used for printed boards and copper foils on both sides of a board, and pressing the whole at a high temperature. Thus, the resistance values can be adjusted at the stage of the inner layer board, trimming after the finish can be omitted, and the printed board has a good heat resistance.</p> |
