US 6,613,413 B1 · Porous power and ground planes for reduced PCB delamination and better reliability

Abstract

Power and ground planes used in Printed Circuit Boards (PCBs) having porous, conductive materials allow liquids (e.g., water and/or other solvents) to pass through the power and ground planes, thus decreasing failures in PCBs (or PCBs used as laminate chip carriers) caused by cathodic/anodic filament growth and delamination of insulators. Porous conductive materials suitable for use in PCBs may be formed by using metal-coated organic cloths (such as polyester or liquid crystal polymers) or fabrics (such as those made from carbon/graphite or glass fibers), using metal wire mesh instead of metal sheets, using sintered metal, or making metal sheets porous by forming an array of holes in the metal sheets. Fabrics and mesh may be woven or random. If an array of holes is formed in a metal sheet, such an array may be formed with no additional processing steps than are performed using conventional PCB assembly methods.

Claims28

Dependent claims

A power/ground core for use in printed circuit boards, the power/ground core comprising:

a first non-conductive water-permeable layer of first fiber laminate;
and a first metal sheet that includes a two-dimensional distribution of through holes formed therethrough,
wherein the first non-conductive layer is in surface contact with the first metal sheet,
wherein the first metal sheet is water permeable only through its through holes,
wherein the through holes in the first metal sheet do not extend into the first non-conductive layer,
wherein the through holes in the first metal sheet have spacings therebetween, and
wherein the spacings and diameters of the through holes in the first metal sheet are sufficient to permit water in the first non-conductive layer to pass through the through holes in the first metal sheet sufficiently fast so as to prevent the water in the first non-conductive layer from collecting at the interface between the first non-conductive layer and the first metal sheet.

4 more elements

A power/ground core for post-production use in printed circuit boards, the power/ground core comprising:

a first non-conductive water-permeable layer of a first fiber laminate;
and a first conductive layer that does not include a metal sheet having a through hole formed therethrough,
wherein the first non-conductive layer is in surface contact with the first conductive layer, and
wherein the first conductive layer comprises a first conductive material that is sufficiently porous to permit water in the first non-conductive layer to pass through the first conductive layer via the first conductive material sufficiently fast so as to prevent the water in the first non-conductive layer from collecting at the interface between the first non-conductive layer and the first conductive layer.

1 more element

Dependencies are inferred from the claim text.

Porous power and ground planes for reduced PCB delamination and better reliability

Life of this patent

Porous power and ground planes for reduced PCB delamination and better reliability

Life of this patent

Abstract

Claims28