| US 7,479,704 B2 | ||
| Substrate improving immobilization of ball pads for BGA packages | ||
| Wen-Jeng Fan, Hsinchu (Taiwan) | ||
| Assigned to Powertech Technology Inc., Hukou Shiang, Hsinchu (Taiwan) | ||
| Filed on Jan. 10, 2007, as Appl. No. 11/651,610. | ||
| Prior Publication US 2008/0164610 A1, Jul. 10, 2008 | ||
| Int. Cl. H01L 23/48 (2006.01) | ||
| U.S. Cl. 257—780 [257/773; 257/738; 257/700; 257/E23.174] | 11 Claims |
| 1. A substrate for BGA packages comprising:
a substrate core having a surface;
a plurality of ball pads, each having a metal pad adhered on the surface of the substrate core and at least a metal nail embedded
into the substrate core;
a solder resist layer formed over the surface of the substrate core and exposing the metal pads; and
a plurality of patterned traces disposed on the surface of the substrate core, connected with the metal pads and covered by
the solder resist layer,
wherein each metal nail has a first end in direct contact with the substrate core and a second end protruding from the exposed
surface of the corresponding metal pad so that the metal nails penetrate the corresponding metal pads but do not penetrate
the substrate core and do not completely cover the exposed surface of the corresponding metal pad.
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