Thin film fabrication technique for implantable electrodes

• US 5,720,099 A
• Filed: 05/01/1996
• Issued: 02/24/1998
• Est. Priority Date: 01/31/1996
• Status: Expired due to Term

• Current Assignee: Cochlear Limited
• Original Assignee: Cochlear Limited
• Inventors: Parker, John L., Treaba, Claudiu
• Primary Examiner(s): Bray, W. Donald
• Application Number:
  US08/641,537
• Time in Patent Office: 664 Days
• Field of Search: 29/25.35, 29/825, 29/830, 29/831, 29/847, 29/851, 29/852, 430/270, 430/312, 430/315, 437/180, 437/181, 437/187, 437/226, 607/5, 607/129
• US Class Current: 29/825
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/0541 Cochlear electrodes
• CPC Class Codes: H01L 21/568 Temporary substrate used as encapsulation process aid H01L21/4832 and H01L21/566 take precedence
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• 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
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 3/20 by affixing prefabricated conductor pattern H05K1/187, H05K3/046, H05K3/4658, H05K3/4682 takes precedence
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/49126 Assembling bases

Abstract

An elongated implantable electrode assembly includes a set of electrode pads arranged in a pre-selected pattern, and a plurality of longitudinal wires, each wire being connected to at least one pad. The electrode assembly is formed by first depositing the pads on a sacrificial layer, adding wires to the pad, embedding the pads and wires in a carrier and then removing the sacrificial layer. These steps can be performed using photolithographic techniques.

Claims

1. A method of making an elongated implantable electrode assembly comprising the steps of:

providing a sacrificial layer;

forming a plurality of pads on said sacrificial layer, said pads being made of an electrically conducting, biocompatible material;

forming a plurality of wires, each wire being connected to at least one of said pads;

embedding said pads and said wires in an electrically nonconductive material to form an assembly body; and

removing said sacrificial layer from said body;

wherein said pads and wires are formed by lithographic techniques.

2. The method of claim 1 wherein said pads and wires are formed of platinum.

3. The method of claim 1 further comprising the step of forming pad connectors between said wires and corresponding pads.

4. The method of claim 1 further comprising forming in said wires reinforcing zones.

5. The method of claim 4 wherein said zones are longitudinally offset.

6. A method of forming an electrode assembly having a plurality of electrodes and wires extending longitudinally through the assembly and connected through said electrodes, said method comprising the steps of:

forming said wires using lithographic techniques;

forming a carrier about said wires, said carrier being made of a flexible non-conducting material; and

removing said sacrificial layer.

7. The method of claim 6 further comprising forming pads on said sacrificial layer using lithographic techniques in a pre-selected pattern, each wire being connected to a corresponding pad.

8. The method of claim 7 wherein said pads are formed substantially simultaneously.

9. The method of claim 7 wherein said pads are partitioned into a number of sets, said method comprising forming the sets of pads separately, each set having its own wires, and then assembling said sets.

10. The method of claim 6 wherein said wires are formed with reinforcing zones.

11. The method of claim 10 wherein said reinforcing zones are formed by forming steps in said wires at predetermined locations.

12. A method of making an elongated implantable electrode assembly comprising the steps of:

providing a sacrificial layer;

forming a plurality of pads on said sacrificial layer, said pads being made of an electrically conducting, biocompatible material;

forming a plurality of wires, each wire being connected to at least one of said pads;

embedding said pads and said wires in an electrically nonconductive material to form an assembly body; and

removing said sacrificial layer from said body;

wherein said wires and pads are formed of a material selected from the group of platinum and iridium.

13. A method of making an elongated implantable electrode assembly comprising the steps of:

providing a sacrificial layer;

forming a plurality of pads on said sacrificial layer, said pads being made of an electrically conducting, biocompatible material;

forming a plurality of wires;

forming pad contacts, each wire being connected to at least one of said pads by a pad contact;

embedding said pads and said wires in an electrically nonconductive material to form an assembly body; and

removing said sacrificial layer from said body.

14. A method of making an elongated implantable electrode assembly comprising the steps of:

providing a sacrificial layer;

forming a plurality of pads on said sacrificial layer, said pads being made of an electrically conducting, biocompatible material;

forming a plurality of wires, each wire being connected to at least one of said pads;

embedding said pads and said wires in an electrically nonconductive material to form an assembly body; and

removing said sacrificial layer from said body;

wherein at least some of said wires are formed with reinforcing zones.