Microchannel forming method and nanotipped dispensing device having a microchannel

• US 20100077515A1
• Filed: 09/05/2006
• Published: 03/25/2010
• Est. Priority Date: 03/16/2004
• Status: Active Grant

• Current Assignee: Northwestern University
• Original Assignee: Northwestern University
• Inventors: Espinosa, Horacio D., Moldovan, Nicolaie A.
• Granted Patent: US 7,775,087 B2
• Time in Patent Office: Days
• US Class Current: 850/40
• CPC Class Codes: B81B 2201/058 Microfluidics not provided for in B81B2201/051 - B81B2201/054
• CPC Class Codes: B81C 1/00071 Channels
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: G01Q 80/00 Applications, other than SPM, of scanning-probe techniques manufacture or treatment of nanostructures B82B3/00; recording or reproducing information using near-field interaction G11B9/12, G11B11/24, G11B13/08
• CPC Class Codes: G03F 7/0002 Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

A method of forming a microchannel as well as a thin film structure including same is made by forming a first thin film on a side of a substrate, forming a fugitive second thin film on the first thin film such that the second thin film defines a precursor of the elongated microchannel and a plurality of extensions connected to and extending transversely relative to the precursor along a length thereof A third thin film is formed on the first thin film and the fugitive second thin film such that the second thin film resides between the first thin film and the third thin film. A respective access site is formed in a region of the third thin film residing on a respective extension and penetrating to the fugitive second thin film. The fugitive second thin film forming the precursor is selectively removed from between the first thin film and the third thin film using an etching medium introduced through the access sites, thereby forming the microchannel between the first thin film and the third thin film. The method preferably further includes forming a sealing layer on the third thin film in a manner to close off open access sites remaining after selective removal of the second thin film.

Claims

14. A method of making a cantilever on a substrate, comprising the steps of:

forming a first thin film on a semiconductor chip substrate to define an elongated cantilever shape on the substrate,

forming a fugitive second thin film on the first thin film such that the second thin film defines a precursor of an elongated microchannel and a plurality of extensions connected to and extending transversely relative to the precursor along a length thereof,

forming a third thin film on the first thin film and the fugitive second thin film such that the fugitive second thin film resides between the first thin film and the third thin film,

forming a respective access site in a region of the third thin film residing on a respective extension and penetrating to the fugitive second thin film,

selectively removing the fugitive second thin film forming the precursor from between the first thin film and the third thin film using an etching medium introduced through the access sites to thereby form a microchannel between the first thin film and the third thin film, and

releasing an end of the cantilever shape from the substrate.

1. A method of forming an elongated microchannel, comprising the steps of:

forming a first thin film on a side of a substrate, forming a fugitive second thin film on the first thin film such that the second thin film defines a precursor of the elongated microchannel and a plurality of extensions connected to and extending transversely relative to the precursor along a length thereof,

forming a third thin film on the first thin film and the fugitive second thin film such that the second thin film resides between the first thin film and the third thin film,

forming a respective access site in a region of the third thin film residing on a respective extension and penetrating to the fugitive second thin film, and

selectively removing the fugitive second thin film forming the precursor from between the first thin film and the third thin film using an etching medium introduced through the access sites, thereby forming a microchannel between the first thin film and the third thin film.

2. The method of claim 1 further including forming a sealing layer on the third thin film in a manner to close off open access sites remaining after selective removal of the second thin film.

3. The method of claim 2 wherein the first thin film is formed to define an elongated cantilever such that the microchannel extends along a length thereof.

4. The method of claim 3 further including forming a piezoelectric actuator layer on the cantilever.

5. The method of claim 4 wherein the actuator layer is formed on the sealing layer.

6. The method of claim 5 wherein the actuator layer is formed on the sealing layer and then the actuator layer and sealing layer are patterned to overlie the cantilever.

7. The method of claim 1 including leaving some of the fugitive second thin film at the extensions after selective removal of the precursor.

8. The method of claim 1 further including forming the first thin film, second thin film, and third thin film on a pointed microtip of the substrate, providing an access site in the third thin film at the microtip and selectively removing the fugitive second layer at the tip using an etching medium introduced through the access site to form an annular space disposed between the first thin film and the third thin film at the microtip and communicated to the microchannel.

9. The method of claim 8 wherein the first thin film comprises diamond.

10. The method of claim 8 wherein the first thin film comprises silicon carbide.

11. The method of claim 1 further including forming a reservoir on an opposite side of the substrate from the first thin film.

12. The method of claim 11 including forming one or more openings in the first thin film layer at a location such that the one or more openings communicate to the reservoir after its formation.

13. The method of claim 12 wherein the one or more openings communicate to another microchannel formed between the microchannel of the cantilever and the reservoir.

15. A thin film structure comprising:

a pair of thin films forming a microchannel therebetween, said microchannel having a plurality of microchannel extensions that extend transversely therefrom along its length, an access site in one of the thin films, and a sealing material closing off the access sites.

16. The structure of claim 14 wherein the extensions of the microchannel contain material of a thin film formerly residing between the pair of thin films.

15-1. The structure of claim 14 wherein the sealing material comprises a sealing layer on one of the thin films.

17. A microcantilever comprising:

a pair of thin films forming an elongated cantilever having a microchannel along its length between the thin films, said microchannel having a plurality of microchannel extensions that extend transversely therefrom along its length, one of the thin films having a respective access site to a respective extension of the microchannel, and a sealing material closing off the access site.

18. The microcantilever of claim 17 further including a piezoelectric actuator layer on one of the thin films.

19. The microcantilever of claim 17 wherein the extensions of the microchannel contain material of a thin film formerly residing between the pair of thin films.

20. The microcantilever of claim 17 further including a microtip for dispensing material.

21. The microcantilever of claim 20 wherein the microtip includes an annular space formed about a pointed tip.

22. The microcantilever of claim 21 wherein the pointed tip comprises diamond.

23. The microcantilever of claim 22 wherein the pointed tip comprises silicon carbide.

24. The microcantilever of claim 20 further including a reservoir on an opposite side of the cantilever from the microtip.

25. The microcantilever of claim 24 wherein one of the thin films includes one or more openings at such a location that the one or more openings communicate to the reservoir.

26. The microcantilever of claim 17 which is formed to extend from a semiconductor chip substrate.