Implantable medical device incorporating miniaturized circuit module

• US 6,567,703 B1
• Filed: 11/08/2000
• Issued: 05/20/2003
• Est. Priority Date: 11/08/2000
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Haubrich, Gregory J., Thompson, David L.
• Primary Examiner(s): JACYNA, J CASIMER
• Application Number:
  US09/708,307
• Time in Patent Office: 923 Days
• Field of Search: 607/36, 607/37, 607/38, 607/1, 607/2, 607/60
• US Class Current: 607/60
• CPC Class Codes: A61N 1/37223 Circuits for electromagnetic coupling
• CPC Class Codes: A61N 1/3758 Packaging of the components within the casing
• CPC Class Codes: Y10S 977/932 for electronic or optoelectronic application
• CPC Class Codes: Y10S 977/94 in a logic circuit

Abstract

Implantable medical devices (IMDS) having RF telemetry capabilities for uplink transmitting patient data and downlink receiving programming commands to and from an external programmer having an improved RF module configured to occupy small spaces within the IMD housing to further effect the miniaturization thereof. An RF module formed of an RF module substrate and at least one IC chip and discrete components has a volume and dimensions that are optimally minimized to reduce its volumetric form factor. Miniaturization techniques include: (1) integrating inductors into one or more IC chips mounted to the RF module substrate; (2) mounting each IC chip into a well of the RF module substrate and using short bonding wires to electrically connect bond pads of the RF module substrate and the IC chip; and (3) surface mounting discrete capacitors over IC chips to reduce space taken up on the RF module substrate. The integrated inductors are preferably fabricated as planar spiral wound conductive traces formed of high conductive metals to reduce trace height and width while maintaining low resistance, thereby reducing parasitic capacitances between adjacent trace side walls and with a ground plane of the IC chip. The spiral winding preferably is square or rectangular, but having truncated turns to eliminate 90° angles that cause point-to-point parasitic capacitances. The planar spiral wound conductive traces are further preferably suspended over the ground plane of the RF module substrate by micromachining underlying substrate material away to thereby reduce parasitic capacitances.

Claims

1. An implantable medical device operable to perform a therapeutic and/or monitoring function comprising:

a housing having a housing side wall and inner and outer wall surfaces of a predetermined contour enclosing a hermetically sealed chamber; and

a battery enclosed within said hermetically sealed chamber;

an electronic circuit module powered by the battery comprising a plurality of discrete components and at least one integrated circuit IC chip mounted to a circuit board having a volumetric form factor dimensioned to fit within said hermetically sealed chamber along with said battery, said electronic circuit module comprising at least one micromachined IC inductor formed integrally with said IC chip thereby reducing the form factor of the electronic circuit module.

2. The implantable medical device of claim 1, wherein the IC inductor comprises a planar spiral formed of a continuous, conductive, spiral trace extending between bonding pads that is deposited as a layer of the IC chip substrate, the spiral trace having turning points that are angled at less than 90°

to reduce parasitic capacitance between adjacent turning points of the spiral trace.

3. The implantable medical device of claim 1, wherein the IC inductor comprises a planar spiral formed of a continuous, conductive, spiral trace extending between bonding pads that is deposited as a layer of the IC chip substrate, the spiral trace and bonding pads consist of a high conductivity conductor selected from the group consisting of gold, copper and aluminum-copper metallization to reduce trace height and width to thereby reduce parasitic capacitances between adjacent turns of the trace and through the IC chip substrate to the ground plane.

4. The implantable medical device of claim 3, wherein the spiral trace and bonding pads consist of a high conductivity conductor selected from the group consisting of gold, copper and aluminum-copper metallization to reduce trace height and width to thereby reduce parasitic capacitances between adjacent turns of the trace and through the IC chip substrate.

5. The implantable medical device of claim 1, wherein the IC chip substrate further comprises a ground plane, and the IC inductor is formed of a planar spiral formed of a continuous conductive trace extending between bonding pads that is suspended above and spaced from said ground plane formed by micromachining substrate material between the exposed surface of the suspended planar spiral and the ground plane away, to thereby reduce parasitic capacitances between adjacent turns of the trace and through the IC chip substrate to the ground plane.

6. The implantable medical device of claim 5, wherein the spiral trace and bonding pads consist of a high conductivity conductor selected from the group consisting of gold, copper and aluminum-copper metallization to reduce trace height and width to thereby reduce parasitic capacitances between adjacent turns of the trace and through the IC chip substrate.

7. The implantable medical device of claim 5, further comprising at least one discrete capacitor mounted to said exposed IC chip surface.

8. The implantable medical device of claim 1, wherein:

said electronic circuit module comprises an RF module incorporating a telemetry transceiver comprising an RF module substrate, an IC chip mounted to said RF module substrate and at least one IC inductor formed integrally with said IC chip thereby reducing the form factor of the RF module.

9. The implantable medical device of claim 8, wherein:

said RF module substrate includes a predetermined RF module substrate thickness, a well formed in said RF module substrate extending from an RF module substrate surface through at least a portion of said RF module substrate thickness, and at least one module bonding pad formed on the RF module substrate surface;

said IC chip includes predetermined IC chip substrate thickness, is mounted within said well of said RF module substrate thereby reducing the form factor of the RF module, and has at least one IC bonding pad formed on an exposed IC chip surface; and

a conductor extending between said module bonding pad and said IC bonding pad.

10. An implantable medical device operable to perform a therapeutic and/or monitoring function comprising:

a housing having a housing side wall and inner and outer wall surfaces of a predetermined contour enclosing a hermetically sealed chamber; and

a battery enclosed within said hermetically sealed chamber; and

an electronic circuit module powered by the battery comprising a plurality of discrete components and at least one integrated circuit IC chip mounted to a circuit board having a volumetric form factor dimensioned to fit within said hermetically sealed chamber along with said battery, said electronic circuit module comprising at least one IC inductor formed integrally with said IC chip thereby reducing the form factor of the electronic circuit module;

wherein the IC inductor comprises a planar spiral formed of a continuous, conductive, spiral trace extending between bonding pads that is deposited as a layer of the IC chip substrate, the spiral trace having turning points that are angled at less than 90°

to reduce parasitic capacitance between adjacent turning points of the spiral trace, and

wherein the spiral trace and bonding pads consist of a high conductivity conductor selected from the group consisting of gold, copper and aluminum-copper metallization to reduce trace height and width to thereby reduce parasitic capacitances between adjacent turns of the trace and through the IC chip substrate.

11. The implantable medical device of claim 10, wherein the IC chip substrate further comprises a ground plane spaced from said planar spiral, and said continuous conductive trace extending between the bonding pads is deposited over an exposed surface of a suspended platform of the IC chip substrate formed by micromachining substrate material between the exposed surface of the suspended platform and the ground plane away, to thereby reduce parasitic capacitances between adjacent turns of the trace through the IC chip substrate to the ground plane.

12. An implantable medical device operable to perform a therapeutic and/or monitoring function comprising:

a housing having a housing side wall and inner and outer wall surfaces of a predetermined contour enclosing a hermetically sealed chamber; and

a battery enclosed within said hermetically sealed chamber; and

an electronic circuit module powered by the battery comprising a plurality of discrete components and at least one integrated circuit IC chip mounted to a circuit board having a volumetric form factor dimensioned to fit within said hermetically sealed chamber along with said battery, said electronic circuit module comprising at least one IC inductor formed integrally with said IC chip thereby reducing the form factor of the electronic circuit module;

wherein the IC inductor is formed of a planar spiral formed of a continuous conductive trace extending between bonding pads that is deposited as a layer of the RF IC chip substrate, the IC chip substrate further comprises a ground plane spaced from said planar spiral, and said continuous conductive trace extending between the bonding pads is deposited over an exposed surface of a suspended platform of the IC chip substrate formed by micromachining substrate material between the exposed surface of the suspended platform and the ground plane away, to thereby reduce parasitic capacitances between adjacent turns of the trace through the IC chip substrate to the ground plane.

13. The implantable medical device of claim 12, wherein the spiral trace and bonding pads consist of a high conductivity conductor selected from the group consisting of gold, copper and aluminum-copper metallization to reduce trace height and width to thereby reduce parasitic capacitances between adjacent turns of the trace and through the IC chip substrate.

14. An implantable medical device operable to perform a therapeutic and/or monitoring function comprising:

a housing having a housing side wall and inner and outer wall surfaces of a predetermined contour enclosing a hermetically sealed chamber; and

a battery enclosed within said hermetically sealed chamber; and

an electronic circuit module powered by the battery comprising a plurality of discrete components and at least one integrated circuit IC chip mounted to a circuit board having a volumetric form factor dimensioned to fit within said hermetically sealed chamber along with said battery, said electronic circuit module comprising at least one IC inductor formed integrally with said IC chip thereby reducing the form factor of the electronic circuit module;

said electronic circuit module comprising an RF module incorporating a telemetry transceiver comprising an RF module substrate, an IC chip mounted to said RF module substrate and at least one IC inductor formed integrally with said IC chip thereby reducing the form factor of the RF module;

said RF module substrate including a predetermined RF module substrate thickness, a well formed in said RF module substrate extending from an RF module substrate surface through at least a portion of said RF module substrate thickness, and at least one module bonding pad formed on the RF module substrate surface;

said IC chip having a predetermined IC chip substrate thickness and being mounted within said well of said RF module substrate thereby reducing the form factor of the RF module, and having at least one IC bonding pad formed on an exposed IC chip surface;

a conductor extending between said module bonding pad and said IC bonding pad; and

at least one discrete capacitor mounted to said exposed IC chip surface.