PCB design and method for providing vented blind vias

Abstract

An apparatus and method for providing a vented blind via in pad of a printed circuit board (PCB). A vent in the blind via in pad to allow gases formed during reflow soldering to escape from the solder joint. In one embodiment, the vent extends from the outer edge of the pad to the blind via. In another embodiment, a method includes forming a blind via in pad having a vent.

What is claimed is:  
     
         1 . An apparatus, comprising: 
 a substrate; and    a via in pad positioned in the substrate, the via in pad including a pad having a vent to provide an escape path for gas from the via in pad, and a blind via disposed in the pad.    
     
     
         2 . The apparatus of  claim 1 , wherein the vent to include a first opening at the outer edge of the pad.  
     
     
         3 . The apparatus of  claim 2 , wherein the vent to include a second opening at the blind via.  
     
     
         4 . The apparatus of  claim 2 , wherein the vent is a wedge.  
     
     
         5 . The apparatus of  claim 3 , wherein the vent is a groove.  
     
     
         6 . The apparatus of  claim 1 , wherein the pad has a plurality of vents.  
     
     
         7 . The apparatus of  claim 2 , wherein the vent to include a second opening at the outer edge of the pad, the vent to not intersect the blind via.  
     
     
         8 . The apparatus of  claim 1 , wherein the vent has a depth that exposes the substrate.  
     
     
         9 . The apparatus of  claim 1 , wherein the blind via to electrically couple the pad to a trace on an inner substrate layer, wherein the substrate is an outer substrate layer of a multilayer printed circuit board having one or more inner substrate layers.  
     
     
         10 . An apparatus, comprising: 
 a first substrate to form an outer layer of a printed circuit board (PCB);    a second substrate to form an inner layer of the PCB, the second substrate having a trace; and    a via in pad positioned in the first substrate electrically coupled to the trace, the via in pad including a pad having a vent to provide an escape path for gas from the via in pad, and a via, disposed in the pad, having a first end at the pad and a second end at the trace.    
     
     
         11 . The apparatus of  claim 10 , wherein the vent to include a first opening at an outer edge of the pad.  
     
     
         12 . The apparatus of  claim 11 , wherein the vent to include a second opening at the via.  
     
     
         13 . The apparatus of  claim 12 , wherein the vent is a groove.  
     
     
         14 . An apparatus, comprising: 
 a substrate; and    one or more via in pads in the substrate, the one or more via in pads each to include a pad and a blind via positioned in the pad, wherein the pad of at least one of the one or more via in pads having a vent to provide an escape path for gas from a gas pocket in the at least one of the one or more via in pads.    
     
     
         15 . The apparatus of  claim 14 , wherein the vent to include a first opening at the outer edge of the pad.  
     
     
         16 . The apparatus of  claim 14 , wherein the vent to include a second opening at the via.  
     
     
         17 . The apparatus of  claim 16 , wherein the vent is a groove.  
     
     
         18 . An apparatus, comprising: 
 a substrate;    a via in pad positioned in the substrate, the via in pad to include a pad and a blind via disposed in the pad; and    means for allowing a gas to escape from a solder joint coupled to the pad.    
     
     
         19 . The apparatus of  claim 18 , wherein the means for allowing a gas to escape includes the pad having a vent, the vent to include a first opening at the outer edge of the pad.  
     
     
         20 . The apparatus of  claim 19 , wherein the vent to include a second opening at the via.  
     
     
         21 . The apparatus of  claim 20 , wherein the vent is a groove.  
     
     
         22 . A system, comprising: 
 a printed circuit board (PCB), comprising: 
 a substrate; and  
 a via in pad positioned in the substrate, the via in pad including: 
 a pad having a vent to provide an escape path for gas from the via in pad, the vent to include a first opening at the outer edge of the pad; and  
 a blind via disposed in the pad; and  
 
   a memory device coupled to the PCB at the via in pad.    
     
     
         23 . The system of  claim 22 , wherein the vent to include a second opening at the blind via.  
     
     
         24 . The system of  claim 23 , wherein the vent is a groove.