| 摘要 |
<p>PROBLEM TO BE SOLVED: To secure high connection reliability even with reduction in size of a via by forming the via nearly in a rectangular or elliptical shape. SOLUTION: A via 1 is formed in such a shape that is elongated in the direction in which there is room to spare to prevent reduction in a connection area of the via 1 itself even with reduction in diameter. The shape of the via 1 is nearly rectangular such as rectangular, rectangular with rounded corners, and elliptical, but preferably is elliptical since a good etching characteristic and a good laser processibility can be achieved. For example, the via 1 is formed in a shape of an ellipse 50μm wide and 100μm long, with the longitudinal dimension being twice as long as the transverse dimension. Due to this shape of the via 1, a connection strength and a conductor resistance value of the via 1 can be the same as those of a larger via, thereby obtaining the same wiring density as with a smaller via.</p> |
