EMI filter terminal assembly with wire bond pads for human implant applications

• US 20050248907A1
• Filed: 07/14/2005
• Published: 11/10/2005
• Est. Priority Date: 02/27/2003
• Status: Active Grant

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch-Sierra, Inc.
• Inventors: Brendel, Richard L., Stevenson, Robert A., Stevenson, Ryan A., Frysz, Christine, Hussein, Haytham, Knappen, Scott
• Granted Patent: US 7,310,216 B2
• Time in Patent Office: Days
• US Class Current: 361/306.200
• CPC Class Codes: A61N 1/3718 Monitoring of or protection against external electromagnetic fields or currents
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/37512 Pacemakers
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: H01G 4/236 leading through the housing, i.e. lead-through
• CPC Class Codes: H01G 4/252 the terminals being coated on the capacitive element H01G4/232 takes precedence
• CPC Class Codes: H01G 4/35 Feed-through capacitors or anti-noise capacitors
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/4847 the connecting portion on the bonding area of the semiconductor or solid-state body being a wedge bond
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00

Abstract

An electromagnetic interference filter terminal assembly for active implantable medical devices includes a structural pad in the form of a substrate or attached wire bond pad, for convenient attachment of wires from the circuitry inside the implantable medical device to the capacitor structure via thermal or ultrasonic bonding, soldering or the like while shielding the capacitor from forces applied to the assembly during attachment of the wires.

Claims

1-174. -174. (canceled)

175. An electromagnetic interference filter terminal assembly for an active implantable medical device, comprising:

a chip capacitor having first and second sets of electrode plates, the second set of electrode plates being conductively coupled to a ground;

a structural pad disposed adjacent to the chip capacitor and conductively coupled to the first set of electrode plates; and

a lead wire conductively coupled to the structural pad;

wherein the structural pad is configured to at least partially protect the chip capacitor from forces incident to conductive coupling of the lead wire to the first set of electrode plates.

176. The assembly of claim 175, wherein the structural pad comprises a wire bond pad attached to a conductive surface of the capacitor.

177. The assembly of claim 176, wherein the wire bond pad has an angled configuration.

178. The assembly of claim 177, wherein a first portion of the wire bond pad is attached to an upper surface of the capacitor and a second portion of the wire bond pad is conductively attached to the conductive surface of the capacitor.

179. The assembly of claim 177, wherein the structural pad includes a substrate disposed between the wire bond pad and the capacitor.

180. The assembly of claim 175, wherein the capacitor includes an aperture extending at least partially therethrough, and a conductive pin disposed within the aperture and conductively coupled to one of the first and second sets of electrode plates.

181. The assembly of claim 180, wherein the structural pad comprises a substrate attached to the capacitor and conductively coupled to the pin.

182. The assembly of claim 181, including a wire bond pad having an extension for attachment of the lead wire thereto.

183. The assembly of claim 175, wherein the structural pad comprises a substrate disposed adjacent to a planar surface of the capacitor.

184. The assembly of claim 183, wherein the substrate comprises a ceramic-based material.

185. The assembly of claim 183, wherein the substrate is selected from an alumina, ceramic, berrylia, aluminum nitride, Fosterite, polyimide, cyanate ester, barium titanate, epoxy or fiber-reinforced material.

186. The assembly of claim 183, wherein the substrate includes a conductive surface trace having a bonding area.

187. The assembly of claim 186, wherein the lead wire is attached to the bonding area.

188. The assembly of claim 183, including an insulative material disposed between the substrate and the capacitor.

189. The assembly of claim 175, wherein the structural pad includes a conductive wire bond pad attached to the substrate, to which the lead wire is conductively coupled.

190. The assembly of claim 189, wherein the wire bond pad is conductively coupled to the first set of electrode plates.

191. The assembly of claim 189, wherein the structural pad includes a substrate disposed adjacent to the capacitor, the wire bond pad being attached to the substrate.

192. The assembly of claim 191, wherein the wire bond pad includes a first portion conductively coupled to the first set of electrode plates, and a second portion conductively coupled to the lead wire.

193. The assembly of claim 192, wherein the first and second portions of the wire bond pad are angularly displaced relative to one another.

194. A process for mechanically protecting an electromagnetic interference (EMI) filter terminal assembly for active implantable medical devices from forces applied when attaching a lead wire thereto, comprising the steps of:

providing an EMI filter having a capacitor;

applying a curable substrate to a surface of the capacitor;

removing the non-cured portion of the substrate; and

attaching conductive material onto the remaining cured portion of the substrate adapted for connection of the lead wire thereto;

wherein the substrate protects the capacitor from forces applied to the terminal assembly during attachment of the lead wire.

195. The process of claim 194, wherein the substrate comprises a nonconductive polyimide.

196. The process of claim 194, wherein the curing step comprises exposing a portion of the polyimide to a radiation source.

197. The process of claim 195, wherein the radiation source comprises the ultraviolet light.

198. The process of claim 196, including the step of placing a mask having a cut-out over the substrate and directing the radiation through the cut-out.

199. The process of claim 194, wherein the applying step comprises the step of spin coating the substrate onto a top surface of the capacitor.

200. The process of claim 194, wherein the removing step comprises exposing the substrate to a chemical wash.

201. The process of claim 194, wherein the attaching step comprises the step of electroplating the substrate with the conductive material.

202. The process of claim 194, wherein the attaching step comprises the step of vaporizing conductive material onto the substrate.

209. An electromagnetic interference filter terminal assembly for an active implantable medical device, comprising:

a conductive ferrule conductively coupled to a housing of the active implantable medical device;

a feedthrough capacitor having first and second sets of electrode plates, the second set of electrode plates being conductively coupled to the ferrule;

a conductive terminal pin extending through the capacitor and conductively coupled to the first set of electrode plates;

a structural pad disposed adjacent to the capacitor, the structural pad including a wire bond pad, wherein the terminal pin is conductively coupled to the first set of electrode plates through the wire bond pad; and

a lead wire conductively coupled to the first set of electrode plates by means of the wire bond pad;

wherein the wire bond pad is configured to at least partially protect the capacitor from forces incident to conductive coupling of the lead wire to the first set of electrode plates.

210. The assembly of claim 209, wherein the structural pad comprises a substrate disposed adjacent to a planar surface of the capacitor.

211. The assembly of claim 210, wherein the substrate comprises a ceramic-based material.

212. The assembly of claim 210, wherein the substrate is selected from an alumina, ceramic, berrylia, aluminum nitride, Fosterite, polyimide, cyanate ester, barium titanate, epoxy or fiber-reinforced material.

213. The assembly of claim 210, including an insulative material disposed between the substrate and the capacitor.

214. The assembly of claim 209, wherein the active implantable medical device comprises a cardiac pacemaker, an implantable defibrillator, a cochlear implant, a neurostimulator, a drug pump, a ventricular assist device, an implantable sensing system, a gastric pacemaker or a prosthetic device.

215. The assembly of claim 210, wherein the wire bond pad is attached to the substrate.

216. The assembly of claim 215, wherein the substrate is disposed adjacent to the capacitor, and the wire bond pad is attached to the substrate.

217. The assembly of claim 209, wherein the wire bond pad includes a first portion conductively coupled to the first set of electrode plates, and a second portion conductively coupled to the lead wire.

218. The assembly of claim 217, wherein the first and second portions of the wire bond pad are angularly displaced relative to one another.

219. The assembly of claim 210, wherein the structural pad comprises a substrate having an aperture into which the terminal pin extends.

220. The assembly of claim 209, wherein the wire bond pad is comprised of Kovar or Alloy 42.

221. The assembly of claim 209, including an electrically insulative material disposed between the wire bond pad and the capacitor.

222. The assembly of claim 209, wherein the wire bond pad includes a socket for receiving an end of the terminal pin therein.

223. The assembly of claim 222, wherein the end of the terminal pin and the wire bond pad are conductively attached to one another.

224. The assembly of claim 219, wherein the terminal pin is conductively coupled to the lead wire, and wherein the substrate aperture is substantially lined with conductive material to define an electrical path from the first set of electrode plates to the lead wire independent of the terminal pin.

225. The assembly of claim 224, wherein the structural pad and the capacitor form a subassembly independent of the ferrule and the terminal pin prior to assembly therewith.

226. The assembly of claim 224, including a conductive insert disposed within a substrate recess for conductively coupling the substrate with the capacitor.

227. The assembly of claim 219, wherein the substrate includes an aperture, hold or slot for facilitating laser welding of the substrate to the terminal pin.

228. The assembly of claim 227, wherein the structural pad comprises a conductive wire bond pad having a socket for receiving an end of the terminal pin therein.

229. The assembly of claim 228, wherein the wire bond pad and the capacitor form a subassembly independent of the ferrule and the terminal pin prior to assembly therewith.

230. The assembly of claim 228, wherein the aperture, hole or slot extends at least partially through the wire bond pad.

231. The assembly of claim 230, wherein the wire bond pad is attached to the capacitor.

232. The assembly of claim 228, wherein the wire bond pad is spaced apart from the capacitor and supported solely on the terminal pin.

233. The assembly of claim 209, wherein a portion of the terminal pin extending from the substrate is bent, and the wire bond pad is configured for placement over the bent portion of the terminal pin.

234. The assembly of claim 219, wherein the structural pad comprises a conductive insert ring disposed within a recess in the substrate, the insert ring being conductively coupled to the terminal pin and the substrate.

235. The assembly of claim 234, wherein the substrate includes a conductive trace conductively coupled to the insert ring, and defining a lead wire bonding area on a surface of the substrate.

236. The assembly of claim 209, wherein the wire bond pad is disposed over an end of the terminal pin.

237. The assembly of claim 209, wherein the structural pad is attached to a surface of the capacitor and is conductively coupled to the terminal pin.

238. The assembly of claim 237, wherein the terminal pin and the wire bond pad are laser welded to one another.

239. The assembly of claim 237, wherein the wire bond pad includes an extension to which the lead wire is attached.

240. The assembly of claim 209, wherein the structural pad is attached to a surface of the capacitor so as to be in conductive relation to the first set of electrode plates, and wherein the wire bond pad is disposed over an end of the terminal pin.

241. The assembly of claim 209, wherein the capacitor is internally grounded.

242. The assembly of claim 209, wherein the capacitor is internally grounded and comprises a plurality of terminal pins, including a ground terminal pin, and the structural pad includes a corresponding number of conductive traces each defining a respective bonding area.

243. The assembly of claim 242, wherein the wire bond pad is conductively bonded with at least one of the bonding areas.

244. The assembly of claim 243, wherein the wire bond pad includes an aperture through which the terminal pin extends.

245. The assembly of claim 244, wherein the terminal pin and the structural pad are electrically connected to one another.

246. The assembly of claim 245, wherein the terminal pin and the structural pad are welded to one another.

247. The assembly of claim 242, wherein a lead wire is attached to one of the wire bonding areas.

248. The assembly of claim 242, wherein the structural pad includes recesses configured for receiving corresponding conductive wire bond pads therein.

249. The assembly of claim 248, wherein the wire bond pads each include an aperture for receiving a respective terminal pin therethrough, each respective terminal pin and wire bond pad being conductively attached to one another.

250. The assembly of claim 249, wherein the terminal pins and the wire bond pads are welded to one another.

251. The assembly of claim 209, wherein the structural pad and the capacitor have aligned leak detection vents.

252. The assembly of claim 209, wherein the ferrule comprises a capture flange into which the capacitor is at least partially disposed.

253. The assembly of claim 209, including an inductor closely associated with the capacitor.

254. The assembly of claim 209, wherein the capacitor is embedded within the ferrule.

255. The assembly of claim 254, including an inductor closely associated with the capacitor.

256. The assembly of claim 209, wherein the structural pad includes a tapered edge.

257. The assembly of claim 256, wherein the capacitor comprises an internally grounded capacitor having multiple apertures therethrough for passage of multiple terminal pins, including a ground pin, and wherein the structural pad includes corresponding aligned apertures and wire bond pads conductively coupled to each terminal pin.

258. The assembly of claim 209, wherein the wire bond pad includes a through-hole or slot to facilitate laser melting of a tip of the terminal pin.

259. The assembly of claim 209, wherein the wire bond pad includes a head configured to lie adjacent to a surface of the capacitor, and a neck extending from the head into the capacitor about an end of the terminal pin.