US 5,870,272 A · Capacitive filter feedthrough for implantable medical device

Abstract

A capacitive filter feedthrough assembly and method of making the same are disclosed for shielding an implantable medical device such as pacemaker or defibrillator from electromagnetic interference or noise. A ferrule is adapted for mounting onto a conductive device housing by welding, soldering, brazing or gluing, and supports a terminal pin for feedthrough passage to a housing interior. A capacitive filter is mounted at the inboard side of a device housing, with capacitive filter electrode plate sets coupled respectively to the housing and the terminal pin by an electrically conductive combination of solder and brazing. In one embodiment of the invention, multiple capacitive filters are provided in an array within a common base structure, where each capacitive filter is associated with a respective terminal pin.

A feedthrough assembly for an implantable medical device, comprising:

(a) an electrically conductive ferrule having a first aperture disposed therethrough, the first aperture having first sidewalls, the ferrule being formed of at least one of titanium, niobium, platinum, molybdenum, zirconium, tantalum, vanadium, tungsten, iridium, rhodium, rhenium, osmium, ruthenium, palladium, silver, and alloys, mixtures and combinations thereof;
(b) an insulator having a second aperture disposed therethrough, the second aperture having second sidewalls, the insulator being disposed within the first aperture and being formed of a ceramic-containing, electrically insulative material;
(c) an electrically conductive pin having upper and lower portions, at least the upper portion of the pin extending into the second aperture, the pin being formed of at least one of titanium, niobium, platinum, molybdenum, zirconium, tantalum, vanadium, tungsten, iridium, rhodium, rhenium, osmium, ruthenium, palladium, silver, and alloys, mixtures and combinations thereof;
(d) an electrically conductive inner braze joint disposed atop the top portion of the pin or between the pin and the second sidewalls of the second aperture, to form a seal therebetween, the inner braze joint being formed of at least one of:
(1) pure gold;
(2) a gold alloy comprising gold and at least one of titanium, niobium, vanadium, nickel, molybdenum, platinum, palladium, ruthenium, silver, rhodium, osmium, iridium, and alloys, mixtures and thereof;
(3) a copper-silver alloy comprising copper, silver and optionally at least one of iridium, titanium, tin, gallium, palladium, platinum, and alloys, mixtures and combinations thereof;
and (4) a silver-palladium-gallium alloy;
(e) an electrically conductive intermediate braze joint disposed between the insulator and the first sidewalls of the first aperture to form a seal therebetween, the intermediate braze joint being formed of at least one of:
(1) pure gold;
(2) a gold alloy comprising gold and at least one of titanium, niobium, vanadium, nickel, molybdenum, platinum, palladium, ruthenium, silver, rhodium, osmium, iridium, and alloys, mixtures and thereof;
(3) a copper-silver alloy comprising copper, silver and optionally at least one of iridium, titanium, tin, gallium, palladium, platinum, and alloys, mixtures and combinations thereof;
and (4) a silver-palladium-gallium alloy;
(f) a ceramic-containing capacitive filter having one of a third aperture and a passageway disposed therethrough, a first electrical terminal being disposed within the third aperture or passageway, a second electrical terminal being disposed on an outer surface of the capacitive filter;
(g) an electrically conductive inner solder joint disposed within the third aperture or the passageway, the inner solder joint being electrically and mechanically connected to the inner braze joint and the first terminal, the inner solder joint being formed of at least one of:
(1) an indium-lead alloy;
(2) indium only;
(3) lead only;
(4) silver only;
(5) tin only;
(6) an indium-silver alloy;
(7) an indium-tin alloy;
(8) a tin-lead alloy;
(9) a tin-silver alloy;
(10) an indium-lead-silver alloy;
(11) a tin-lead-silver alloy;
(12) a gold-tin alloy;
(13) a gold-silicon alloy;
(14) a gold-germanium alloy;
and (15) a gold-indium alloy;
(h) an electrically conductive outer braze joint disposed between the ferrule and the outer surface of the capacitive filter, the outer braze joint being formed of at least one of:
(1) pure gold;
(2) a gold alloy comprising gold and at least one of titanium, niobium, vanadium, nickel, molybdenum, platinum, palladium, ruthenium, silver, rhodium, osmium, iridium, and alloys, mixtures and thereof;
(3) a copper-silver alloy comprising copper, silver and optionally at least one of iridium, titanium, tin, gallium, palladium, platinum, and alloys, mixtures and combinations thereof;
and (4) a silver-palladium-gallium alloy, and
(i) an electrically conductive outer solder joint disposed between the outer braze joint and the second electrical terminal, the outer solder joint electrically and mechanically connecting the outer braze joint to the second terminal, the outer solder joint being formed of at least one of:
(1) an indium-lead alloy;
(2) indium only;
(3) lead only;
(4) silver only;
(5) tin only;
(6) an indium-silver alloy;
(7) an indium-tin alloy;
(8) a tin-lead alloy;
(9) a tin-silver alloy;
(10) an indium-lead-silver alloy;
(11) a tin-lead-silver alloy;
(12) a gold-tin alloy;
(13) a gold-silicon alloy;
(14) a gold-germanium alloy;
and (15) a gold-indium alloy;
wherein the capacitive filter, in combination with the electrical connections established to the first and second terminals thereof from, respectively, the pin and the ferrule, attenuates electromagnetic interference when installed in an implantable medical device.

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Capacitive filter feedthrough for implantable medical device

Life of this patent

Capacitive filter feedthrough for implantable medical device

Life of this patent

Abstract

Claims87