| 摘要 |
PROBLEM TO BE SOLVED: To provide a printed board where a solder protrusion with the height of over 250μm is not formed even when a through-hole is filled with solder by a flow solder method. SOLUTION: The printed board 1, 5 is obtained by producing a through-hole 3 in a lamination base material 20, 50, forming, on the rear surface of the lamination base material, an insulating protective film 42, 62 having an opening to expose the through-hole, and performing metal plating 24, 25 on the exposure surface of the lamination base material, thereby forming second land 24b, 25b in the opening of the insulating protective film on the rear surface of the lamination base material. The through-hole is formed to have a circular transverse section with a radius R equal to or less than 0.75 mm, and also the second land is formed to have a ring shape whose size is equal to or less thanπ(0.6R+0.09) mm<SP>2</SP>, or the through-hole is formed to have a circular transverse section with the radius R more than 0.75 mm and equal to or less than 1.0 mm, and also the second land is formed to have a ring shape whose size is equal to or less thanπ(0.2R+0.01) mm<SP>2</SP>. COPYRIGHT: (C)2009,JPO&INPIT
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