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Crack Detection Test for Plated Hole

IP.com Disclosure Number: IPCOM000078856D
Original Publication Date: 1973-Mar-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Mesley, NN: AUTHOR

Abstract

Cracks occurring within the copper of plated-through holes due to thermal stresses can be easily detected, by pulling a circuit line with attached hole land from the substrate. After soldering, most of the solder is removed by conventional leveling techniques to leave a thin layer of solder over the copper surface. A circuit line leading to the land at a hole location is then peeled off the insulative laminate. This causes the surface copper to pull away from the copper plating in the hole. Microscopic examination will then reveal whether the parting occurred at a preexisting crack. This method requires significantly less time than the usual cross-sectioning technique.

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Crack Detection Test for Plated Hole

Cracks occurring within the copper of plated-through holes due to thermal stresses can be easily detected, by pulling a circuit line with attached hole land from the substrate. After soldering, most of the solder is removed by conventional leveling techniques to leave a thin layer of solder over the copper surface. A circuit line leading to the land at a hole location is then peeled off the insulative laminate. This causes the surface copper to pull away from the copper plating in the hole. Microscopic examination will then reveal whether the parting occurred at a preexisting crack. This method requires significantly less time than the usual cross-sectioning technique.

Butt joint failures, discontinuities between surface copper and the plated copper in the hole, can also be detected by the pull technique. If there is a butt joint failure, the plated copper within the hole will remain intact when the surface circuit and and land are peeled away. Usually the copper within the hole will protrude above the substrate surface in the case of failure.

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