| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a circuit board with high drop resistance and a manufacturing method therefor. <P>SOLUTION: The circuit board includes a substrate 21; copper wiring patterns 22 formed on the substrate 21; solder resist layers 23 for covering the substrate and copper patterns; and solder bumps 27. The solder resist layers 23 are formed with contact holes 24, that reach the copper wiring patterns 22 from the surfaces thereof. Each of the contact holes 24 has a undercut 29 formed. Inside of each contact hole 24 is formed with an Ni layer 25, which is connected to the copper wiring pattern 22. The top surface of the Ni layer 25 is located apart from the front end 29a of the undercut 29 by 6 to 30μm, desirably, by 10μm or larger. On the interface between the Ni layer 25 and the solder bump 27, an alloy layer 26 of Ni and Sn is formed. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
