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High Performance Printed Circuits Made With Low Dielectric Materials

IP.com Disclosure Number: IPCOM000035957D
Original Publication Date: 1989-Aug-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Ellis, TL: AUTHOR [+2]

Abstract

A printed circuit board is made from materials having low dielectric constants. The low dielectric-constant materials, when placed between the printed circuit signal transmission lines and the nearest reference plane, increase the propagation velocity of the circuits, resulting in much higher performance.

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High Performance Printed Circuits Made With Low Dielectric Materials

A printed circuit board is made from materials having low dielectric constants. The low dielectric-constant materials, when placed between the printed circuit signal transmission lines and the nearest reference plane, increase the propagation velocity of the circuits, resulting in much higher performance.

In a typical embodiment, the multilayer printed circuit structure is fabricated using a series of processes, as depicted in the figure:

1. A power core is laminated from two sheets of copper and a sheet of low dielectric-constant material. The insulating layer can be polytetrafluoroethylene (PTFE) polymer, fluorinated ehtylene- propylene (FEP) copolymer, or any other polymeric material, either filled with glass fibers, particulate matter, air, or other polymers, or unfilled. These materials have a dielectric constant in the 2 to 3 range, and must be heated above their melting point (400 to 800 degrees Fahrenheit) in order to flow enough to bond to the copper.

2. The clearance holes for the plated through holes in the multilayer printed circuit are then drilled in the power core. At this time, electrical isolation slots, fixture holes, and all other through holes which do not make electrical contact with the power planes are drilled and/or milled in the power core.

3. The clearance holes and isolation slots are then filled with an insulating material, which is not necessarily of low dielectric c...