Sacrificial layers for bio-compatible devices

• US 9,282,920 B2
• Filed: 08/27/2013
• Issued: 03/15/2016
• Est. Priority Date: 08/27/2013
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Verily Life Sciences LLC (Alphabet Inc.)
• Inventors: Ho, Harvey, Etzkorn, James, Yao, Huanfen
• Primary Examiner(s): NIKMANESH, SEAHVOSH J
• Application Number:
  US14/011,478
• Publication Number:
  US 20150065820A1
• Time in Patent Office: 931 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0214 of power generation or supply
• CPC Class Codes: A61B 2562/125 characterised by the manufacture of electrodes
• CPC Class Codes: A61B 5/002 Monitoring the patient using a local or closed circuit, e.g. in a room or building A61B5/0017 takes precedence
• CPC Class Codes: A61B 5/14503 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors A61B5/1459, A61B5/1464, A61B5/1473, A61B5/1482, A61B5/14865 take precedence
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: A61B 5/6821 Eye
• CPC Class Codes: G02C 7/04 Contact lenses for the eyes disinfection or sterilisation of contact lenses A61L12/00

Abstract

A method may involve: forming a sacrificial layer on a working substrate; forming a first bio-compatible layer on the sacrificial layer such that the first bio-compatible layer adheres to the sacrificial layer; forming a conductive pattern on the first bio-compatible layer; mounting an electronic component to the conductive pattern; forming a second bio-compatible layer over the first bio-compatible layer, the electronic component, and the conductive pattern; and removing the sacrificial layer to release the bio-compatible device from the working substrate. The first bio-compatible layer defines a first side of a bio-compatible device. The second bio-compatible layer defines a second side of the bio-compatible device.

Claims

1. A method comprising:

forming a sacrificial layer on a working substrate;

forming a first bio-compatible layer on the sacrificial layer such that the first bio-compatible layer adheres to the sacrificial layer, wherein the first bio-compatible layer defines a first side of a bio-compatible device;

forming a conductive pattern on the first bio-compatible layer;

mounting an electronic component to the conductive pattern;

forming a second bio-compatible layer over the first bio-compatible layer, the electronic component, and the conductive pattern, wherein the second bio-compatible layer defines a second side of the bio-compatible device; and

removing the sacrificial layer to release the bio-compatible device from the working substrate.

2. The method of claim 1, wherein the sacrificial layer comprises one or more metal layers.

3. The method of claim 2, wherein the first bio-compatible layer adheres to at least one metal layer of the one or more metal layers via hydrogen bonds.

4. The method of claim 1, wherein the sacrificial layer comprises one or more photoresist layers.

5. The method of claim 4, wherein at least one photoresist layer of the one or more photoresist layers is aligned with a location on the first bio-compatible layer where the electronic component is mounted to the conductive pattern.

6. The method of claim 5, wherein the at least one photoresist layer has at least one dimension that is greater than a corresponding dimension of the electronic component.

7. The method of claim 5, wherein the sacrificial layer further comprises one or more metal layers, and wherein the at least one photoresist layer is formed over at least one metal layer of the one or more metal layers.

8. The method of claim 1, wherein the sacrificial layer comprises one or more metal layers formed over one or more photoresist layers.

9. The method of claim 1, wherein the sacrificial layer comprises at least one photoresist layer that is patterned negatively.

10. The method of claim 1, wherein the sacrificial layer comprises one or more materials selected from the group consisting of aluminum, titanium, chromium, 1-methoxy-2-propanol acetate, 2-ethoxyethyl acetate, and cyclohexanone.

11. The method of claim 1, wherein the sacrificial layer comprises one or more photoresist layers and one or more metal layers, and wherein at least one photoresist layer of the one or more photoresist layers is thicker than at least one metal layer of the one or more metal layers.

12. The method of claim 1, further comprising:

applying an adhesion promoter to a surface of the sacrificial layer.

13. The method of claim 1, further comprising:

treating a surface of the sacrificial layer, such that a surface of the first bio-compatible layer bonds to the treated surface of the sacrificial layer during formation of the first bio-compatible layer.

14. The method of claim 1, wherein removing the sacrificial layer to release the bio-compatible device from the working substrate comprises:

etching a portion of the second and first bio-compatible layers using an inductively coupled plasma, such that a portion of the sacrificial layer is exposed; and

dissolving the sacrificial layer in a fluid.

15. The method of claim 12, wherein the fluid comprises 1-methyl-2-pyrrolidone.

16. The method of claim 1, wherein removing the sacrificial layer to release the bio-compatible device from the working substrate comprises etching the sacrificial layer.

17. The method of claim 1, wherein removing the sacrificial layer to release the bio-compatible device from the working substrate comprises:

etching a portion of the second and first bio-compatible layers and a first portion of the sacrificial layer using an inductively coupled plasma; and

dissolving a second portion of the sacrificial layer in a fluid.

18. The method of claim 1, wherein the sacrificial layer comprises one or more photoresist layers, and wherein removing the sacrificial layer to release the bio-compatible device from the working substrate comprises etching under at least one photoresist layer of the one or more photoresist layers.