Thin film stent

• US 6,096,175 A
• Filed: 07/17/1998
• Issued: 08/01/2000
• Est. Priority Date: 07/17/1998
• Status: Expired due to Term

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Micro Therapeutics, Inc. (Medtronic Plc)
• Inventors: Roth, Noah M.
• Primary Examiner(s): Nuzzolillo, Maria
• Assistant Examiner(s): Mercado, Julian A
• Application Number:
  US09/118,729
• Time in Patent Office: 746 Days
• Field of Search: 204/192.14, 204/192.15, 204/192.23, 216/37, 216/87, 216/89, 216/83, 623/1, 419/38, 419/49, 148/559
• US Class Current: 204/192.15
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2210/0076 multilayered, e.g. laminated structures
• CPC Class Codes: A61F 2240/001 Designing or manufacturing processes
• CPC Class Codes: A61L 31/022 Metals or alloys
• CPC Class Codes: C23C 14/0005 Separation of the coating from the substrate

Abstract

A method for fabricating a stent or other medical device by creating a free standing thin film of metal.

Claims

1. A method for manufacturing a body implantable stent, said method comprising:

providing a substrate susceptible to degradation upon application of a substrate etchant;

sputter depositing a thin film of material onto the substrate;

applying a substrate etchant to the substrate to degrade the substrate, thereby releasing the thin film of material from the substrate;

forming the thin film of material into a stent.

2. The method of claim 1 further comprising:

photochemically machining a pattern of perforations into the thin film before releasing the thin film of material from the substrate.

3. The method of claim 1 wherein:

the substrate used is comprised of silicon;

the material which is sputter deposited is nitinol;

the silicon substrate is provided with a layer of silicon oxide, and the thin film is deposited over the layer of silicon oxide;

the substrate etchant is applied to dissolve the layer of silicon oxide, thereby releasing the thin film from the substrate.

4. The method of claim 3 further comprising:

photochemically machining a pattern of perforations into the thin film.

5. The method of claim 3 further comprising:

photochemically machining a pattern of perforations into the thin film, performing said photochemical machining before releasing the thin film from the substrate.

6. The method of claim 3 further comprising:

photochemically machining a pattern of perforations into the thin film, wherein said step of photochemically machining a perforation pattern comprises the steps of (1) applying a photoresist coating on the surface of the thin film, (2) removing the photoresist in the areas of desired perforations (3) chemically etching the thin film in film etchant to remove the thin film material under the areas of desired perforations and (4) removing the photoresist from the surface of the thin film.

7. The method of claim 3 further comprising:

photochemically machining a pattern of perforations into the thin film before removing the thin film from the substrate, wherein said step of photochemically machining a perforation pattern comprises the steps of (1) applying a photoresist coating on the surface of the thin film, (2) removing the photoresist in the areas of desired perforations (3) chemically etching the thin film in film etchant to remove the thin film material under the areas of desired perforations and (4) removing the photoresist from the surface of the thin film.

8. A method of forming a stent comprising:

providing a target comprising a material;

providing a thin film deposition chamber capable of removing molecules from the target;

providing a substrate and placing the substrate within the thin film deposition chamber;

operating the thin film deposition chamber to remove molecules from the target and cause said removed molecules to condense on the substrate and form a deposited film on the substrate;

releasing a deposited film from the substrate;

forming the deposited film into a stent.

9. The method of claim 8 further comprising:

perforating the stent through a photochemical etching process.

10. The method of claim 8, further comprising the steps of:

prior to forming the deposited film on the substrate, coating the substrate with a layer of waste material;

photochemically etching the layer of waste material to impart a pattern of perforations in the waste material;

thereafter forming the deposited film on the substrate coated with the etched layer of waste material; and

removing the waste material.

11. The method of claim 8, further comprising the steps of:

after forming the deposited film on the substrate, coating the deposited film with a layer of photoresist;

imaging and developing the layer of photoresist to impart a pattern of perforations in the photoresist, leaving areas of the deposited film exposed;

etching the deposited film with an etchant to remove exposed portions of the deposited film.

12. The method of claim 10, wherein the etching of the deposited film is done prior to removal of the medical device from the substrate.

13. The method of claim 8, where the target is comprised of nitinol.

14. A method of forming a stent comprising:

providing a target comprising a material;

providing a sputter deposition chamber capable of removing molecules from the target;

providing a substrate and placing the substrate within the sputter deposition chamber;

operating the sputter deposition chamber to remove molecules from the target and cause said removed molecules to condense on the substrate and form a deposited film on the substrate;

releasing the deposited film from the substrate;

forming the deposited film into a stent;

hipping stent.