Hermetic terminal for an active implantable medical device having a feedthrough capacitor partially overhanging a ferrule for high effective capacitance area

A filter feedthrough that is attachable to an active implantable medical device (AIMD), the filter feedthrough comprising:

• a) a feedthrough, comprising:
• i) an electrically conductive ferrule comprising:
• A) a ferrule sidewall extending to a ferrule body fluid side end surface and to a ferrule device side end surface, the ferrule sidewall further comprising a ferrule outermost surface and a ferrule inner surface defining a ferrule opening extending to the ferrule body fluid and device side end surfaces with a peninsula extending from the ferrule sidewall inwardly into the ferrule opening,
• B) wherein the ferrule outermost surface comprises opposed ferrule first and second outermost surface portions meeting opposed ferrule third and fourth outermost surface portions, and
• C) wherein when the ferrule is attached to an opening in a housing of an AIMD, the ferrule body fluid side end surface and the ferrule device side end surface reside outside the AIMD and inside the AIMD, respectively;
• ii) an insulator at least partially residing in the ferrule opening where the insulator is hermetically sealed to the ferrule, the insulator extending to an insulator body fluid side end surface and to an insulator device side end surface located adjacent to the ferrule body fluid and device side end surfaces, respectively;
• iii) at least one active via hole extending through the insulator to the insulator body fluid and device side end surfaces;
• and
• iv) an active conductive pathway at least partially residing in and hermetically sealed to the insulator in the at least one active via hole;
• and
• b) a feedthrough capacitor disposed on the device side of the ferrule, the feedthrough capacitor comprising:
• i) a capacitor dielectric having a capacitor dielectric outer sidewall extending to a capacitor dielectric first end surface and to a capacitor dielectric second end surface, wherein the capacitor dielectric outer sidewall comprises opposed capacitor dielectric first and second outer sidewall portions meeting opposed capacitor dielectric third and fourth outer sidewall portions;
• ii) at least one active electrode plate interleaved in a capacitive relationship with at least one ground electrode plate in the capacitor dielectric;
• iii) at least one active passageway extending through the capacitor dielectric to the capacitor dielectric first and second end surfaces;
• iv) a capacitor active metallization contacting the capacitor dielectric in the at least one active passageway and being in an electrically conductive relation with the at least one active electrode plate;
• v) at least one ground passageway extending through the capacitor dielectric to the capacitor dielectric first and second end surfaces;
• vi) a capacitor ground metallization first portion contacting the capacitor dielectric outer sidewall and being in an electrically conductive relation with the at least one ground electrode plate;
• and
• vii) a capacitor ground metallization second portion residing in the at least one ground passageway and being in an electrically conductive relation with the at least one ground electrode plate;
• and
• c) a first electrical connection material electrically connecting the active conductive pathway residing in the at least one active via hole in the insulator to the active metallization electrically connected to the at least one active electrode plate of the feedthrough capacitor;
• d) a second electrical connection material first portion electrically connecting the capacitor ground metallization first portion electrically connected to the at least one ground electrode plate at the capacitor dielectric outer sidewall to the ferrule, and a second electrical connection material second portion electrically connecting the capacitor ground metallization second portion electrically connected to the at least one ground electrode plate in the at least one ground passageway of the feedthrough capacitor to the ferrule peninsula;
• e) wherein an imaginary projection of the ferrule outermost surface onto the capacitor dielectric second end surface provides the ferrule first and second outermost surface portions intersecting the capacitor dielectric third and fourth outer sidewall portions to thereby define:
• A) a capacitor dielectric first overhang portion comprising the capacitor dielectric first outer sidewall portion extending laterally outwardly beyond the ferrule first outermost surface portion;
• B) a capacitor dielectric imaginary second overlay portion overlaying the ferrule device side end surface and the insulator device side end surface, wherein at least one of the capacitor dielectric third and fourth outer sidewall portions in the capacitor dielectric imaginary second overlay portion is spaced inwardly from the ferrule outermost surface, and wherein the at least one ground electrode plate at least partially resides in the capacitor dielectric imaginary second overlay portion;
• and
• C) wherein the capacitor ground metallization first portion contacting at least one of the capacitor dielectric third and fourth outer sidewall portions in the capacitor dielectric imaginary second overlay portion is electrically connected to the ferrule device side end surface, spaced inwardly from a corresponding one of the at least one of the ferrule third and fourth outermost surface portions, by the second electrical connection material first portion.

A filter feedthrough configured to be installed in an opening of a housing an active implantable medical device (AIMD), the filter feedthrough comprising:

• a) an electrically conductive ferrule separating a body fluid side opposite a device side, the body fluid side configured to reside outside the AIMD housing and the device side configured to reside inside the AIMD housing, the ferrule including a ferrule opening extending between and to the body fluid side and the device side;
• b) an insulator hermetically sealing the ferrule opening;
• c) at least one conductive pathway hermetically sealed to and disposed through the insulator between the body fluid side and the device side, the at least one conductive pathway being in non-electrically conductive relation with the ferrule;
• and
• d) a feedthrough capacitor disposed on the device side,
• e) wherein at least a first edge of the feedthrough capacitor extends beyond a first outermost edge of the ferrule, and
• f) wherein at least a second edge of the feedthrough capacitor does not extend beyond a second outermost edge of the ferrule.

A filter feedthrough configured to be installed in an opening of a housing an active implantable medical device (AIMD), the filter feedthrough comprising:

• a) an electrically conductive ferrule separating a body fluid side opposite a device side, the body fluid side configured to reside outside the AIMD housing and the device side configured to reside inside the AIMD housing, the ferrule including a ferrule opening extending between and to the body fluid side and the device side;
• b) an insulator hermetically sealing the ferrule opening by at least one of a first gold braze, a ceramic seal, a glass seal or a glass-ceramic;
• c) at least one conductive pathway hermetically sealed to and disposed through the insulator between the body fluid side and the device side, the at least one conductive pathway being in non-electrically conductive relation with the ferrule;
• and
• d) a feedthrough capacitor disposed on the device side, the feedthrough capacitor comprising:
• i) at least one active electrode plate disposed parallel and spaced from at least one ground electrode plate, wherein the at least one active and ground electrode plates are disposed within a capacitor dielectric;
• ii) a capacitor active metallization electrically connected to the at least one active electrode plate and in non-electrically conductive relation with the at least one ground electrode plate;
• and
• iii) a capacitor ground metallization electrically connected to the at least one ground electrode plate and in non-electrically conductive relation with the at least one active electrode plate,
• e) wherein the capacitor active metallization is electrically connected to the at least one conductive pathway, and
• f) wherein the capacitor ground metallization is electrically connected to the ferrule, and
• g) wherein at least a first edge of the feedthrough capacitor extends beyond a first outermost edge of the ferrule, and
• h) wherein at least a second edge of the feedthrough capacitor is either aligned with or is set back from a second outermost edge of the ferrule, and
• i) wherein the ferrule has a rectangular shape, the first outermost edge and the second outermost edge forming at least a part of the rectangular shape, and
• j) wherein the first outermost edge is perpendicularly disposed in relation to the second outermost edge.