An approx. 35 micrometre thick electrolytically precipitated copper foil is used as carrier with a strongly structured surface profile on one side. On this structured surface is applied a 100 micrometre thick layer of an organic UV-hardenable polymer as an insulation layer. The lined foil is then laminated to the surface of a fibreglass epoxy laminate which is provided with a connection pattern of copper. Lamination occurs under pressure and heat between flat plates, and with the polymer layer turned towards the connection pattern, but before lamination the space between the plates is evacuated. - Then the copper foil is removed by etching, and the polymer layer is dried at low heat, and illuminated with ultra-violet light through a mask so that only parts which are required to remain are lit and hardened. The non-hardened parts are dissolved away using a solvent which does not attack the hardened parts. In this way, the underlying connection pattern contact points have the apertures leading to them disclosed. Chemical and electrolytic metalling is effected so that all surfaces of the insulation layer and apertures are lined with a copper layer approx. 100 micrometres thick. (Provisional basic advised week 87/48)(0/4)
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