| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress the cracking of a joint part between a solder bump of a BGA(ball grid array package) and a pad part of a printed circuit board in the mount structure of an electronic component mounted on the printed circuit board by using a solder paste printing and reflow method. SOLUTION: The printed circuit board 20 has via holes 23 for leading an internal wiring layer 22 out to one surface, pad parts 24 are all arranged on one surface 21 of the printed circuit board at positions matching the via holes 23, and on the one surface 21 of the printed circuit board 20, solder resist 25 is formed not covering entire pad parts 24.</p> |
