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AssigneeLenovo Enterprise Solutions (Singapore) Pte. Ltd.
InventorsJoseph Kuczynski, Melissa K. Miller, Heidi D. Williams, Jing Zhang
Estimating the term…
A conductive via and method of forming a conductive via in a multilayer printed circuit board are disclosed. A hole is drilled into a printed circuit board that is reinforced with glass fibers, wherein the hole extends between two conductive elements on different layers of the printed circuit board and cuts through a portion of the glass fibers. A tungsten nitride layer is then deposited on the walls of the hole, wherein the tungsten nitride layer has a thickness between 1.5 nanometers and 20 nanometers. A copper layer is deposited over the tungsten nitride layer, wherein the copper and tungsten nitride form a conductive via that provides an electrically conductive pathway between the two conductive elements, and wherein the tungsten nitride layer isolates the copper layer from the glass fibers.
A method of forming a via in a multilayer printed circuit board comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
Forming printed elements for providing electric connections to or between printed circuits: plated through-holes or plated via connections
Plated through-holes or plated via connections: blind plated via connections
Properties and characteristics in general: thin film conductor layer; Thin film passive component
Printed circuits
About 7 years 10 months of term left · ends 4 Sep 2034 (estimated)
1. Field of the Invention
The present invention relates to printed circuit board structures that include internal copper structures.
2. Background of the Related Art
FIG. 1 is a cross-sectional side view of a printed circuit board having a plated through hole in accordance with the present invention.
FIG. 2 is a cross-sectional side view of a printed circuit board having a blind via in accordance with the present invention.
FIG. 3 is a cross-sectional side view of a printed circuit board having a buried via in accordance with the present invention.
One embodiment of the present invention provides a method of forming a via (“vertical interconnect access”) in a multilayer printed circuit board. The method comprises drilling a hole into a printed circuit board that is reinforced with glass fibers, wherein the hole extends between two conductive elements on different layers of the printed circuit board and cuts through a portion of the glass fibers. A tungsten nitride layer is then deposited on the walls of the hole, wherein the tungsten nitride layer has a thickness between 1.5 nanometers and 20 nanometers. The method further comprises depositing a copper layer over the tungsten nitride layer, wherein the copper and tungsten nitride form a conductive via that provides an electrically conductive pathway between the two conductive elements, and wherein the tungsten nitride layer isolates the copper layer from the glass fibers.
Each end of a via typically terminates in a pad that makes electrical contact with conductive elements. Non-limiting examples of a conductive element include an electronic component secured to printed circuit board, a conductive trace formed on the surface of the printed circuit board, and a conductive trace or plane within the printed circuit board. A typical printed circuit board will include at least one conductive power plane and at least one conductive ground plane. Furthermore, the printed circuit board may comprise an epoxy resin.
The via extends between conductive layers of a printed circuit board. Depending upon which conductive layers are intended to be connected, the via may be selected from a plated through hole, a blind via, and a buried via. A “plated through hole” extends through all of the layers of the printed circuit board from a top surface to a bottom surface. A “blind via” extends from one surface of the printed circuit board to an internal conductive component, such as a trace, power plane or ground plane. A “buried via” extends between two internal conductive components, without extending to either of the top or bottom surfaces of the printed circuit board.