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Hole Fill of Heavy Copper Power Plane Using Compatible Epoxy Resin Prior to Composite Lamination

IP.com Disclosure Number: IPCOM000036135D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Samuelson, CE: AUTHOR

Abstract

Thick copper power planes are required in order to dissipate heat in applications where high amperage is used. The copper power planes contain clearance holes that must be filled before the power planes are laminated into a composite in order to prevent voids. A method that fills both the clearance holes and the first isolation border is accomplished in the following manner.

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Hole Fill of Heavy Copper Power Plane Using Compatible Epoxy Resin Prior to Composite Lamination

Thick copper power planes are required in order to dissipate heat in applications where high amperage is used. The copper power planes contain clearance holes that must be filled before the power planes are laminated into a composite in order to prevent voids. A method that fills both the clearance holes and the first isolation border is accomplished in the following manner.

When the clearance holes and the first isolation border are milled into the power plane, identical holes and isolation borders are milled in a 1 oz. sheet of copper foil. The 1 oz copper foil is registered over the thick copper plane with the shiny or bright side of the foil facing the thick copper, making sure that good alignment is established between the parts. A layer of prepreg is placed underneath the heavy copper to ensure mechanical strength required between the first and second isolation border patterns. Above the 1 oz copper foil mask layers of prepreg are stacked, the height depending on the thickness of the copper foil being used. A release film is then placed on both top and bottom of the layup next to planishing plates. The configuration is shown in Fig. 1.

This stack or multiple stacks are then placed in a lamination press where heat and pressure are applied. The epoxy resin contained in the prepreg layers directly above the 1 oz copper foil mask flows under heat and pressure and co...