Horizontally Split Vias
First Claim
1. An apparatus, comprising:
- a substrate having a plurality of insulator layers and internal conductive traces, wherein a first through-hole extends completely through the substrate from a first surface of the substrate to a second surface of the substrate, wherein the first through-hole passes through a first and a second of the internal conductive traces, and wherein the second internal conductive trace lies deeper within the substrate with respect to the substrate'"'"'s first surface than does the first internal conductive trace;
a first conductive via plated onto the first through-hole, wherein the first conductive via extends from the substrate'"'"'s first surface to and terminates substantially at the first internal conductive trace;
a second conductive via plated onto the first through-hole, wherein the second conductive via extends from the substrate'"'"'s second surface to and terminates substantially at the second internal conductive trace.
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Accused Products
Abstract
A mechanism is disclosed for providing horizontally split vias are provided in printed wiring boards (PWBs) and other substrates. In one embodiment, the substrate includes a plurality of insulator layers and internal conductive traces. First and second through-holes extend completely through the substrate and respectively pass through first/second ones and third/fourth ones of the internal conductive traces, which are at different depths within the substrate. Photolithographic techniques are used to generate plated-through-hole (PTH) plugs of controlled, variable depth in the through-holes before first/second conductive vias are plated onto the first through-hole and before third/fourth conductive vias are plated onto the second through-hole. The depth of these PTH plugs is controlled (e.g., using a photomask and/or variable laser power) to prevent the conductive vias from extending substantially beyond their respective internal conductive traces, thereby horizontally spitting the two conductive vias plated onto each of the through-holes. This advantageously increases wiring density up to 2×.
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Citations
19 Claims
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1. An apparatus, comprising:
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a substrate having a plurality of insulator layers and internal conductive traces, wherein a first through-hole extends completely through the substrate from a first surface of the substrate to a second surface of the substrate, wherein the first through-hole passes through a first and a second of the internal conductive traces, and wherein the second internal conductive trace lies deeper within the substrate with respect to the substrate'"'"'s first surface than does the first internal conductive trace; a first conductive via plated onto the first through-hole, wherein the first conductive via extends from the substrate'"'"'s first surface to and terminates substantially at the first internal conductive trace; a second conductive via plated onto the first through-hole, wherein the second conductive via extends from the substrate'"'"'s second surface to and terminates substantially at the second internal conductive trace. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method comprising the steps of:
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providing a substrate having a plurality of insulator layers and a plurality of internal conductive traces, wherein a plurality of through-holes extend completely through the substrate from a first surface of the substrate to a second surface of the substrate, wherein a first one of the through-holes passes through a first and a second of the internal conductive traces, and wherein the second internal conductive trace lies deeper within the substrate with respect to the substrate'"'"'s first surface than does the first internal conductive trace; plating a first conductive via onto the first through-hole so that the first conductive via extends from the substrate'"'"'s first surface to and terminates substantially at the first internal conductive trace; plating a second conductive via onto the first through-hole so that the second conductive via extends from the substrate'"'"'s second surface to and terminates substantially at the second internal conductive trace. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method comprising the steps of:
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providing a substrate having a plurality of insulator layers and a plurality of internal conductive traces, wherein a plurality of through-holes extend completely through the substrate from a first surface of the substrate to a second surface of the substrate, wherein a first one of the through-holes passes through a first and a second of the internal conductive traces, wherein the second internal conductive trace lies deeper within the substrate with respect to the substrate'"'"'s first surface than does the first internal conductive trace, wherein a second one of the through-holes passes through a third and a fourth of the internal conductive traces, and wherein the fourth internal conductive trace lies deeper within the substrate with respect to the substrate'"'"'s first surface than does the third internal conductive trace; plating a first conductive via onto the first through-hole so that the first conductive via extends from the substrate'"'"'s first surface to and terminates substantially at the first internal conductive trace; plating a second conductive via onto the first through-hole so that the second conductive via extends from the substrate'"'"'s second surface to and terminates substantially at the second internal conductive trace; plating a third conductive via onto the second through-hole so that the third conductive via extends from the substrate'"'"'s first surface to and terminates substantially at the third internal conductive trace; plating a fourth conductive via onto the second through-hole so that the fourth conductive via extends from the substrate'"'"'s second surface to and terminates substantially at the fourth internal conductive trace. - View Dependent Claims (19)
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Specification