LEAD-FRAME STRUCTURE, LEAD-FRAME, SURFACE MOUNT ELECTRONIC DEVICE AND METHODS OF PRODUCING SAME

• Main Authors: NEOH, Din-Ghee, BARTHELMES, Jürgen
• Format: Patent
• Language: English; French
• Published: 14.09.2017
• Subjects: APPARATUS THEREFOR; BASIC ELECTRIC ELEMENTS; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; ELECTROFORMING; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTIONOF COATINGS; SEMICONDUCTOR DEVICES; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION

In order to provide a more reliable and cost-efficient way of producing lead-frames or lead- frames structures which expose treated silver surfaces as well as to provide surface mount electronic devices using such lead-frames or lead-frames structures, a method comprising the following method steps carried out in this order is provided: (a) providing a lead-frame body structure having two main sides, said lead-frame body structure exclusively exposing a copper surface on each one of said main sides; (b) depositing a silver coating on at least one of said main sides, so that said at least one of said main sides at least partially exposes an untreated silver surface; and (c) electrolytically treating said untreated silver surface on said at least one of said main sides generated in method step (b) with a treatment solution containing at least one hydroxide compound selected from alkali metal hydroxides, alkaline earth metal hydroxides, ammonium hydroxides and mixtures thereof, wherein the lead-frame body structure is a cathode, thereby producing a lead-frame structure which comprises at least two lead-frame entities each one having two faces and at least partially exposing said treated silver surface; wherein said at least one of said two faces of at least one of said lead-frame entities either exclusively exposes said treated silver surface or wherein said at least one of said two faces of said at least one of said lead-frame entities partially exposes said treated silver surface and partially exposes said copper surface, wherein, on each one of said two faces of each one of said lead-frame entities which partially exposes said treated silver surface, the area of said copper surface is smaller than the area of said treated silver surface. Afin de fournir une méthode de production plus fiable et rentable de grilles de connexion ou de structures de grille de connexion qui exposent les surfaces d'argent traitées et afin de fournir des dispositifs électroniques à montage en surface utilisant de telles grilles de connexion ou structures de grille de connexion, l'invention concerne un procédé comprenant les étapes suivantes, effectuées dans cet ordre, consistant à : (a) utiliser une structure de corps de grille de connexion ayant deux côtés principaux, ladite structure de corps de grille de connexion exposant exclusivement une surface de cuivre sur chacun desdits côtés principaux ; (b) déposer un revêtement d'argent sur au moins un desdits côtés principaux, de sorte que ledit ou lesdits côtés principaux exposent au moins partiellement une surface d'argent non traitée ; et (c) traiter électrolytiquement ladite surface d'argent non traitée sur ledit ou lesdits côtés principaux générée à l'étape (b) avec une solution de traitement contenant au moins un composé hydroxyde choisi parmi les hydroxydes de métal alcalin, les hydroxydes de métal alcalino-terreux, les hydroxydes d'ammonium et leurs mélanges, la structure de corps de grille de connexion étant une cathode, ce qui produit une structure de grille de connexion qui comprend au moins deux entités de grille de connexion ayant chacune deux faces et exposant au moins partiellement ladite surface d'argent traitée ; ladite ou lesdites deux faces d'au moins une desdites entités de grille de connexion exposant exclusivement ladite surface d'argent traitée ou ladite ou lesdites deux faces d'au moins une desdites entités de grille de connexion exposant partiellement ladite surface d'argent traitée et exposant partiellement ladite surface de cuivre, la superficie de ladite surface de cuivre étant, sur chacune desdites deux faces de chacune desdites entités de grille de connexion qui expose partiellement ladite surface d'argent traitée, inférieure à la superficie de ladite surface d'argent traitée.