| 摘要 |
<p>PURPOSE:To form a foaming insulating film so as to obtain a short circuit preventing function, selecting a required thickness of it to meet the preventing function with a layer of the insulating film by a method wherein the main component of a solder resist printing ink is made to contain a foaming agent. CONSTITUTION:A conductor 2 consisting of a required pattern is formed on one side of a insulating board 1, and a foaming solder resist film 3 is formed on the side of the substrate 1 where the conductor 2 has been formed. The foaming solder resist film 3 is print//ed on the conductor 2 forming face of the board 1 through a silk screen printing, making use of a solder resist ink whose main component contains 2-5 parts by weight of a foaming agent, which is heated up to a temperature (for example. 100-200 deg.C) that the compounded foaming agent is dissolved to foam and set through a required means such as irradiation with ultraviolet or the like to be formed.</p> |
