Dual-drill printed circuit board via

Abstract

A printed circuit board having multiple layers of circuitry, the printed circuit board including a first layer having a first cylindrical opening with a first diameter, the first cylindrical opening formed through at least the first layer and formed about a particular axis; and a second layer having a second cylindrical opening with a second diameter, the second cylindrical opening formed through at least the second layer and formed about the particular axis, where the first cylindrical opening is a portion of a conductive via, and where the second diameter is smaller than the first diameter.

What is claimed is: 
     
         1 . A method of forming vias on a printed circuit board having multiple layers of circuitry, the method comprising:
 forming, about a particular axis, a first cylindrical opening with a first diameter through at least a first layer of the printed circuit board; and   forming, about the particular axis, a second cylindrical opening with a second diameter through at least a second layer of the printed circuit board,   wherein the first cylindrical opening and the second cylindrical opening are portions of a conductive via, and   wherein the second diameter is smaller than the first diameter.   
     
     
         2 . The method of  claim 1 ,
 wherein forming the second cylindrical opening further comprises drilling, using a drill bit having the second diameter, a cylindrical opening through the first layer followed by the second layer, and   wherein forming the first cylindrical opening further comprises after forming the cylindrical opening with the second diameter through the first layer and the second layer, drilling, using a drill bit having the first diameter, the first cylindrical opening through at least the first layer.   
     
     
         3 . The method of  claim 1 ,
 wherein forming the first cylindrical opening further comprises drilling, in a first direction along the particular axis, the first cylindrical opening through at least the first layer of the printed circuit board,   wherein forming the second cylindrical opening further comprises drilling, in a second direction along the particular axis that is opposite to the first direction, the second cylindrical opening through at least the second layer of the printed circuit board.   
     
     
         4 . The method of  claim 3 ,
 wherein forming the second cylindrical opening further comprises forming the second cylindrical opening through at least a third layer of the printed circuit board that is between the first layer and the second layer, and   wherein the method further comprises:   after forming the second cylindrical opening, forming, in the second direction along the particular axis, a third cylindrical opening with a third diameter through at least the second layer of the printed circuit board, wherein the third cylindrical opening is a portion of the conductive via, and wherein the second diameter is smaller than the third diameter.   
     
     
         5 . The method of  claim 1 , further comprising:
 forming, through at least the first layer and about a different axis that is parallel to the particular axis, a third cylindrical opening with the second diameter; and   forming, through at least the second layer and about the different axis, a fourth cylindrical opening with the first diameter,   wherein the fourth cylindrical opening is a portion of a different conductive via.   
     
     
         6 . The method of  claim 5 , wherein the third cylindrical opening is a portion of the different conductive via. 
     
     
         7 . The method of  claim 5 , further comprising:
 forming, through at least a third layer and about the particular axis, a fifth cylindrical opening with a third diameter; and   forming, through at least a fourth layer and about the different axis, a sixth cylindrical opening with the third diameter,   wherein the third layer and the fourth layer are arranged between the first layer and the second layer,   wherein the third diameter is smaller than the second diameter,   wherein the fifth cylindrical opening is a portion of the conductive via,   wherein the sixth cylindrical opening is a portion of the different conductive via, and   wherein the second cylindrical opening and the third cylindrical opening are non-conductive.   
     
     
         8 . The method of  claim 5 ,
 wherein the first layer includes a pair of conductive traces, and   wherein a first conductive trace of the pair of conductive traces is electrically coupled to the conductive via.   
     
     
         9 . The method of  claim 1 , further comprising:
 forming, through at least the first layer and the second layer and about a different axis that is parallel to the particular axis, a third cylindrical opening with the first diameter,   wherein the third cylindrical opening is a portion of a ground via coupled to a ground voltage.