Process for producing plated through-hole printed circuit boards having very small solder lands or no solder lands

The invention relates to a method for producing printed circuit boards with through-plated holes and very small solder lands, or no solder lands, in accordance with the Tenting method. In the case of the Tenting method there is a risk of the photographic film (5) tearing off and etching medium penet...

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Bibliographic Details
Main Authors MERKENSCHLAGER, HANS-HERMANN, ZEIDLER, WOLFGANG
Format Patent
LanguageEnglish
French
German
Published 16.08.1995
Edition5
Subjects
CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS
ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
ELECTRICITY
MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
PRINTED CIRCUITS
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Summary:The invention relates to a method for producing printed circuit boards with through-plated holes and very small solder lands, or no solder lands, in accordance with the Tenting method. In the case of the Tenting method there is a risk of the photographic film (5) tearing off and etching medium penetrating into the through-plated holes (3) and damaging the copper layer (2) located on the hole walls. In order to avoid this disadvantage, the invention provides that the printed circuit board is provided with an etching-resistant protective film (4) before being coated with photographic film (5). Once the conductor pattern has been developed, the etching-resistant protective film (4) is removed from the free copper surface (2) by briefly treating in acid, and the conductor pattern structure is then produced using alkaline etching medium. Once the photographic film (5) has been stripped off, the protective film (4) is removed from the walls of the through-plated holes (3) by means of acid.
Bibliography:Application Number: EP19930118077