International Business Machines Corporation

Ivan I Chobot

Thurston Bryce Youngs, Jr

Reinaldo Anthony Neira

John A Covert

Alexander Petrovich

Paul C Sviedrys

Louise A Tiemann

Donald W Miller

Gerald A Valenta

Keith D Mansfield

Randy L Haight

Robert A Martone

A multi-layer printed circuit board or card including at least one passage in at least one of the layers of the circuit board or card for preventing the diffusion of heat throughout the circuit board or card during the securing or removal of components in plated through holes in the circuit board or card by the heating of the plating material to a temperature above a melting point of the plating material.

Method of forming electronic multilayer printed circuit boards or cards

The present invention increases real estate by providing non-annular lands which do not completely encircle the through holes. The non-annular lands are non-annular, that is they do not extend 360.degree. around the through hole. Preferably the non-annular lands contact no more than one side of the through holes thereby providing real estate not otherwise available using conventional lands. The present invention also relates to a method for producing such Non-annular lands.

Non-annular lands

A method of forming a multi-layer circuit board or card. The method includes the step of forming a plurality of conductive planes. The conductive planes include ground, signal, or power planes. At least one through hole is formed through at least one of the conductive planes. An electrically conductive material is deposited onto an inside surface of the at least one through hole to form a plated through hole. At least one thermal relief passage is formed at least in the at least one of the conductive planes for preventing the diffusion of heat throughout the circuit board or card during the securing or removal or chips or other components to the circuit board or card by heating the material deposited in the at least one through hole to a temperature above its melting point. The at least one thermal relief passage is located in the vicinity of the at least one through hole and is free from electrical connection therewith. An electrically insulating material is deposited on at least one side of each of the conductive planes. The planes are placed on top of each other such that a layer of electrically insulating material is located between each of the conductive planes. The conductive planes are joined together to form the multi-layer circuit board or card.

Methods of forming electronic multi-layer printed circuit boards and/or

Printed circuit board or card thermal mass design

Growing community of inventors

Whitby, Canada

Ivan I Chobot