| 摘要 |
PROBLEM TO BE SOLVED: To solve the problems in prior art where all small holes of many printed boards having many small holes, especially through-holes, e.g. BGA, CSP, F/CBGA boards must be planarized uniformly in short time to meet the today's demands for making lighter, thinner, more compact, high-density and multilayer products, and where the conventional methods are inferior in quality, yield and cost. SOLUTION: After sandwiching a board having holes filled with a solder resist between an upper and lower resin layers from which solvents have been removed by heating, flat solder resist films with no rise are formed by the press method, required portions are cured by UV, unwanted uncured portions are developed and removed, the solder resist is heat set to fill up the holes, and at the same time, patterns are formed to form protective films.
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