Mounting method for chip carriers on substrate - uses intermediate ceramic carrier plate which is glued to substrate and allows differential thermal strains

• Main Author: JEAN-CLAUDE VALLET ET JACQUES DE GIVRY
• Format: Patent
• Language: English; French
• Published: 16.09.1983
• Subjects: BASIC ELECTRIC ELEMENTS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION ORPROCESSING OF GOODS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS; PRINTED CIRCUITS; SEMICONDUCTOR DEVICES; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE

The component mounting system provides a means of connecting a multi-terminal device such as a chip-carrier, to a circuit substrate where the coefficients of expansivity of the component package and substrate (10) may be very different. The component (11) is mounted on an intermediate ceramic plate (16) which is slightly larger than the component and has a number of pre-tinned contact pads (17) around its periphery. The component has its own terminal contacts (15) soldered to the pads. Flexible wave leads (18) from the pads to the substrate circuit terminating pads (13). The substrate has metal ground plane (21). A metal stud (20) is fixed to the component and fits into a hole through the intermediate layer and substrate. It gives the mounting extra mechanical solidity and provides heat dissipation. The intermediate layer is glued to the substrate surface using a polyurethane adhesive which allows dilation relative to the substrate. After all the solder connections have been made, the whole circuit assembly is covered with a layer of insulating varnish. POUR MONTER, SUR UN SUPPORT 10 PORTANT UN CIRCUIT, DES COMPOSANTS ELECTRONIQUES 11 TELS QUE DES PORTE-PUCE A FIXER A PLAT, MUNIS SUR LEUR FACE INFERIEURE DE CONTACTS SOUDABLES ET POUR RELIER LES COMPOSANTS AU CIRCUIT, ON FIXE D'ABORD A PLAT LE COMPOSANT PAR L'INTERMEDIAIRE D'UNE PLAQUETTE INTERCALAIRE 16. LA PLAQUETTE EST EN UN MATERIAU AYANT UN COEFFICIENT DE DILATION THERMIQUE COMPATIBLE AVEC LE COMPOSANT. LES LIAISONS ELECTRIQUES SONT EFFECTUEES PAR SOUDAGE DES PLAGES DE CONTACTS DU COMPOSANT SUR UN RESEAU CONDUCTEUR 17 PREVU SUR LA PLAQUETTE INTERCALAIRE ET PAR FIXATION DE TRONCONS DE FILS 14 ENTRE LE RESEAU ET LE CIRCUIT.