Browse Prior Art Database

High performance PWB Structure

IP.com Disclosure Number: IPCOM000015061D
Original Publication Date: 2002-Jun-13
Included in the Prior Art Database: 2003-Jun-20
Document File: 1 page(s) / 43K

Publishing Venue

IBM

Abstract

The present disclosure provides a unique printed wiring board (PWB) structure that enables manufacturing of a very complex design containing 65 Land Grid Array modules, greater than 85,000 0.012" diameter plated through holes (PTH), greater than 62,000 buried vias, 20 signal layers and 18 ounces of power planes. Construction of such a complex PWB by conventional means (eg. Signal-Signal, Power-Power, Signal-Signal cores) would result in an almost non-manufacturable board having a cross-section of approximately 0.200" thick. Drilling and plating of 0.014" diameter drilled holes in a board that is 0.200" thick would result in very poor yields at best.

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High performance PWB Structure

    The present disclosure provides a unique printed wiring board (PWB) structure that enables manufacturing of a very complex design containing 65 Land Grid Array modules, greater than 85,000 - 0.012" diameter plated through holes (PTH), greater than 62,000 buried vias, 20 signal layers and 18 ounces of power planes. Construction of such a complex PWB by conventional means (eg. Signal-Signal, Power-Power, Signal-Signal cores) would result in an almost non-manufacturable board having a cross-section of approximately 0.200" thick. Drilling and plating of 0.014" diameter drilled holes in a board that is 0.200" thick would result in very poor yields at best.

The unique structure utilized to meet all requirements, yet provide a manufacturable structure was to utilize 2 oz stand-alone power planes sandwiched between each pair of signal planes as pictured in the partial cross-section below. The 2 oz stand-alone power planes provided the required power distribution while also enabling conveyor processing of stand-alone copper foils. The structure further eliminated the pre-preg between power planes that is associated with a conventional PWB structure, and thus enabled total cross-section thickness to be reduced from the conventional 0.200" to 0.150". The 0.150" overall thickness provided drill and plate capability of 0.014" diameter holes at very high yields.

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