| 摘要 |
PURPOSE:To prevent the migration of ions in a conductive substance formed in through holes and the like when a voltage is applied under such a condition as to cause condensation on the printed wiring board. CONSTITUTION:Conductive paste is filled into through holes, blind viaholes and access type through viaholes, and is hardened to form a conductive substance. As a result, in a double-sided board or multilayer printed wiring board where specified circuits are electrically connected through such conductive substances, a protective coating 9 is formed on the entire surface of the conductive substance to prevent the migration of its ions. The coating 9 use a material that is resistant to high temperature and humidity (85 deg.C, 80%RH or above), water repellent, and excellent in printability and adhesion. |
