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Hole Fabrication by Electron Beam Method

IP.com Disclosure Number: IPCOM000095028D
Original Publication Date: 1965-Aug-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Hudolin, HF: AUTHOR

Abstract

To make holes in printed circuit board 11 using the beam from electron beam source 13, top copper mask 15 and bottom copper mask 17 both having openings 19 are used. When board 11 is multilayered or thick as shown, openings 19 are slightly larger than the holes which are desired so that taper at the bottom of hole 20 is minimized. Repeated firing of the beam produces clean holes.

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Hole Fabrication by Electron Beam Method

To make holes in printed circuit board 11 using the beam from electron beam source 13, top copper mask 15 and bottom copper mask 17 both having openings 19 are used. When board 11 is multilayered or thick as shown, openings 19 are slightly larger than the holes which are desired so that taper at the bottom of hole 20 is minimized. Repeated firing of the beam produces clean holes.

With thin laminates of copper foil 21 and a plastic substrate or base 23, two beam pulses gave clean holes. Masks 15 and 17 absorb heat in order to reduce the heat affected area and thus eliminate copper blistering and separation between the copper foil and the plastic substrate. The latter can be made from epoxy-resin-glass-fibers or polypropylene, for example.

The assembly of mask and workpiece can be stepped under a pulsed beam. Another method is interrupting the beam and stepping the workpiece through a stationary mask setup.

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