Patent ID: 6969471

Claim:
A process for manufacturing printed circuit boards with protected spaces between tracks, of the type comprising the steps of: a) arranging an initial board made up of a substrate ( 1 ) in the form of a two-sided board of a dielectric material, and at least one plate ( 2 ) of a conducting material, joined by means of a layer of adhesive ( 8 ) to at least one of said sides of the substrate ( 1 ); b) removing, by means of a selective chemical milling process with photoresist, areas of said plate ( 2 ) to provide tracks ( 5 ) of said conducting material joined to said substrate ( 1 ) and separated by spaces between tracks ( 6 ); c) applying on said substrate ( 1 ) and tracks ( 5 ) a resinous electroinsulating filler material ( 7 ) to fill said spaces between tracks ( 6 ), covering the tracks ( 5 ), and hardening said filler material ( 7 ) by heat or ultraviolet radiation; and d) applying an abrasion treatment on the filler material ( 7 ) and upper part of the tracks ( 5 ) to obtain flush upper surfaces ( 3 ) of the filler material ( 7 ) and tracks ( 5 ), characterized in that it comprises the additional step of: e) after step c) and during step d), subjecting the printed circuit board to cooling to carry out a reduction of temperature in the filler material ( 7 ) to below its glass transition temperature.