LEAD FINISHING FOR A SURFACE MOUNT PACKAGE

摘要

A surface mount box (60) includes a plurality of outer case conductors (64) with a finished double surface (66, 68). The lower part of the conductor which must be linked to a connection block (74) of a substrate (70), such as a printed circuit board, is provided with a surface (68) wettable with solder, said surface extending only over part of the length of the conductor (64) in order to meet a part (66) of non-wettable surface. Alternatively or additionally, the upper parts of the conductors (64) can be coated using a chemical composition, a plastic composition or another composition rejecting the solder (84), making it possible to obtain the part ( 66) of non-wettable surface. The links obtained through the use of said conductors (64) are more resistant and more reliable, thanks to the affinity of the solder (72) for the conductor (64) at the level of the contact zone (74) and thanks to the reluctance of the solder (72) to bring the conductor, like a wick, in the non-wettable zone (66) of the conductor (64) closer to the housing (60) thus moving the solder (72) away from the connection zone ( 74). The configuration of the solder joint can be changed quickly and easily by controlling the area or depth of the region (68) coated by the solder only on the bottom of the conductors (64) of the surface mount box (60) to integrated circuits.