X-CROSS NON-CIRCULAR MICRO VIAS FOR LAYER INTERCONNECT IN PRINTED WIRING BOARD
A printed circuit board (PCB) may include a first layer including a first plurality of conductive pads spaced apart from each other, a second layer including a second plurality of conductive pads spaced apart from each other, a first plurality of non-circular shaped micro vias connecting between the first plurality of conductive pads of the first layer and the second plurality of conductive pads of the second layer, a third layer including a third plurality of conductive pads spaced apart from each other, and a second plurality of non-circular shaped micro vias connecting between the second plurality of conductive pads of the second layer and the third plurality of conductive pads of the third layer. The second plurality of non-circular shaped micro vias may be rotated at an angle from the first plurality of non-circular shaped micro vias to form an offset pattern along an X-Y plane.
1 . A stack of layers for a printed circuit board (PCB), the stack comprising:
a first layer comprising a first plurality of conductive pads spaced apart from each other;
a second layer comprising a second plurality of conductive pads spaced apart from each other;
a first plurality of non-circular shaped micro vias connecting between the first plurality of conductive pads of the first layer and the second plurality of conductive pads of the second layer;
a third layer comprising a third plurality of conductive pads spaced apart from each other;
a second plurality of non-circular shaped micro vias connecting between the second plurality of conductive pads of the second layer and the third plurality of conductive pads of the third layer,
wherein the second plurality of non-circular shaped micro vias are rotated at a first angle from the first plurality of non-circular shaped micro vias to form an offset pattern along an X-Y plane.
2 . The stack of claim 1 , wherein the non-circular shaped micro vias comprise oval or oblong micro vias.
3 . The stack of claim 2 , wherein the third layer is a breakout layer, wherein the third plurality of conductive pads are non-circular shaped.
4 . The stack of claim 2 , further comprising:
a fourth layer comprising a fourth plurality of conductive pads spaced apart from each other; and
a third plurality of non-circular shaped micro vias connecting between the third plurality of conductive pads of the third layer and the fourth plurality of conductive pads of the fourth layer, wherein the third plurality of non-circular shaped micro vias are rotated at a second angle from the second plurality of non-circular shaped micro vias.
5 . The stack of claim 4 , wherein the fourth layer is a breakout layer, and the fourth plurality of conductive pads are non-circular shaped.
6 . The stack of claim 1 , wherein the first angle ranges from 0 to 180 degrees.
7 . The stack of claim 1 , wherein the third layer is a breakout layer, wherein the non-circular shaped vias comprise “+” or cross-shaped micro vias.
8 . The stack of claim 7 , wherein the third plurality of conductive pads are circular shaped.
9 . The stack of claim 7 , further comprising:
a fourth layer comprising a fourth plurality of conductive pads spaced apart from each other; and
a third plurality of non-circular shaped micro vias connecting between the third plurality of conductive pads of the third layer and the fourth plurality of conductive pads of the fourth layer, wherein the third plurality of non-circular shaped micro vias are rotated at a second angle from the second plurality of non-circular shaped micro vias.
10 . The stack of claim 7 , wherein the first angle ranges from 0 to 90 degrees.
11 . The stack of claim 1 , wherein the second plurality of non-circular shaped micro vias is aligned with the first plurality of non-circular shaped micro vias along a Z-axis perpendicular to the X-Y plane.
12 . The stack of claim 1 , wherein the second plurality of non-circular shaped micro vias is offset from the first plurality of non-circular shaped micro vias along an X-axis or a Y axis of the X-Y plane.
13 . A stack of layers for a printed circuit board (PCB) including a ball grid array (BGA), the stack comprising:
a first layer comprising circular pads or rounded square pads and a first set of routing traces, the circular pads or rounded square pads being divided into a first group of outer pads and a second group of inner pads, the first set of routing traces connecting to the first group of outer pads;
a second layer comprising outer non-circular pads, inner circular or rounded square pads, and a second set of routing traces connecting to the outer non-circular pads; and
a third layer comprising non-circular pads and a third set of routing traces connecting to the non-circular pads of the third layer.
14 . The stack of claim 13 , further comprising a first plurality of non-circular shaped micro vias connecting between a subset of the second group of the inner pads of the first layer and the outer non-circular pads of the second layer.
15 . The stack of claim 14 , further comprising a second plurality of non-circular shaped micro vias connecting between the inner circular or rounded square pads of the second layer and the non-circular pads of the third layer.
16 . The stack of claim 15 , wherein the second plurality of non-circular shaped micro vias are rotated at an angle from the first plurality of non-circular shaped micro vias to form an offset pattern along an X-Y plane with an offset angle ranging from 0 to 180 degrees.
17 . The stack of claim 15 , wherein each of the first plurality and the second plurality of the non-circular shaped micro vias comprise oval or oblong micro vias.
18 . The stack of claim 15 , wherein each of the first plurality and the second plurality of the non-circular shaped micro vias comprise “+” or cross-shaped micro vias.
19 . The stack of claim 13 , wherein the BGA has a pitch of 0.4 mm, wherein the BGA is a 10 by 10 array.
20 . A stack of layers for a printed circuit board (PCB) including a ball grid array (BGA), the stack comprising:
a first layer comprising circular pads or rounded square pads and a first set of routing traces, the circular pads or rounded square pads being divided into a first group of outer pads and a second group of inner pads, the first set of routing traces connecting to the first group of outer pads; and
a second layer comprising non-circular pads and a second set of routing traces connecting to the non-circular pads.
21 . The stack of claim 20 , further comprising a plurality of non-circular shaped micro vias connecting between a subset of the second group of the inner pads of the first layer and the non-circular pads of the second layer.
22 . The stack of claim 20 , wherein the BGA has a pitch of 0.5 mm, wherein the BGA is a 6 by 6 array.