Motorola Corporation

Loren E Saar

Theodore V Lester

Jerry David Meyerhoff

James E Bebak

Frank A Sardina

Joseph J Vinci

An improved method for fabricating a circuit element through a substrate permits fabrication of large geometry vias between substrate sides. The improved method includes disposing a substrate (327) between two compressible layers (317, 339). Each of the layers (317, 339) has at least one aperture (345, 321) disposed therethrough. The substrate (327), has at least one via (333) aligned between the apertures (345, 321) where the via has an area smaller than an area of the apertures (345, 321). Next, a coating, preferably a liquid circuit element material (351) is disposed into one of the apertures (321) of one of the two compressible layers (339). A pressure (405) is applied between the two compressible layers (317, 339) causing the liquid circuit element material (351) to flow between the two compressible layers (317, 339), thereby coating the at least one via (333) of the substrate (327), thus providing an interconnect (609, 611) of the coating through the substrate (327). The compressed layers (317, 339) confine the spreading of the liquid circuit element material (351). Preferably, the substrate (327) is then cured or fired, thereby changing the liquid circuit element material (351) into a solid state.

Method for fabricating a circuit element through a substrate

A controllable fuse (10; 40; 50; 60; 80) has a pair of isolated conductor pads (26, 27), a solder connection (32; 41; 51) connected to the pads and providing a circuit connection therebetween, and at least one heater (14; 70, 75) to produce heat in response to an electrical signal. When sufficient heat is provided, the solder connection will desolder and disconnect the circuit connection between the conductor pads (26, 27). Major features are that the conductor pads and the heater are provided on a planar surface(s) (19, 25) as planar films and that redundancy for the fuse can be implemented by providing more than one heater (70, 75). A preferred manufacturing method for the fuse is disclosed which utilizes a solder retaining structure. Several fuse configurations are illustrated.

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Elmwood Park, IL, United States of America

Loren E Saar