| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a printed wiring board which has a high adhesive strength between a connection part and an insulating substrate and between the connection part and a solder, and which is not likely to cause an electrical malfunction caused by flow of underfill; and which has a high strength of a solder resist layer, a high adhesive strength between the solder resist layer and the under fill, and which successively removes a smear.SOLUTION: A printed wiring board which has on an insulating substrate, a circuit board where a connection part for connecting an electronic component, and a solder resist layer having an opening on a surface of the circuit board, and in which the connection part is partially exposed from the solder resist layer at the opening and which comprises: a structure in which an opening width of the opening upper part at the opening of the solder resist layer is not lager than an opening width of the opening bottom.</p> |
