Browse Prior Art Database

Crack Resistant Plated Through Holes for Multilayer Interconnection Boards

IP.com Disclosure Number: IPCOM000077897D
Original Publication Date: 1972-Oct-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Wild, RN: AUTHOR

Abstract

Multilayer interconnection board 10 comprises plural internal conductors 11 and 12, separated by layers of dielectric material 13 in the usual manner. Through-holes 14 and 15 having internal conductive platings 16, provide electrical connection for external tabs 17 and certain of the internal conductors 12. Thermal stresses are set up in the through-hole platings 16 when heat is applied for soldering components, terminal pins or other external connectors to the through-holes. The stresses are particularly severe in circuit boards which are very thick, having a large number of internal conductive planes or which are of very high density.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 95% of the total text.

Page 1 of 2

Crack Resistant Plated Through Holes for Multilayer Interconnection Boards

Multilayer interconnection board 10 comprises plural internal conductors 11 and 12, separated by layers of dielectric material 13 in the usual manner. Through-holes 14 and 15 having internal conductive platings 16, provide electrical connection for external tabs 17 and certain of the internal conductors
12. Thermal stresses are set up in the through-hole platings 16 when heat is applied for soldering components, terminal pins or other external connectors to the through-holes. The stresses are particularly severe in circuit boards which are very thick, having a large number of internal conductive planes or which are of very high density. The thermal stress on the platings of the through-holes 14 and 15 frequently cause cracking in the plating 16 at the juncture with the tabs 17 or the internal layers 12, particularly if located near the surface of the board 10.

This cracking has found to be controllable by providing through-hole inner plane stress rings 18 at the upper and lower regions of the board. The stress rings 18 are preferably much thicker than the internal conductors 11 and 12, and are attached to the via hole plating 16 in substantially the same manner as inner plane conductors are connected. A particularly suitable stress ring 18 for a multilayer board 10 having inner conductors uses two ounce copper for the stress rings 10, while the inner conductors 11 and 12 were one ounce cop...