| 摘要 |
PURPOSE:To prevent cracks from occurring, by boring two species of holes different in their diameters from each other when a plurality of pin holes for use in an integrated circuit are bored at prescribed pitches on one straight line. CONSTITUTION:When pin holes for use in an integrated circuit are bored at narrow pitches in a printed wiring substrate 21 in order to make the integrated circuit compact, two species of holes 22A and 22B, which are a little different in their diameters to each other, are alternately bored at prescribed pitches on one straight line. Even if each pitch between their holes is smaller than conventional one, an interval between facing edges of the pin holes 22A and 22B adjacent to each other becomes essentially large accordingly, so that cracks can be prevented from occurring between their pin holes.
|
