Method of fabricating nanometer-scale flowchannels and trenches with self-aligned electrodes and the structures formed by the same

• US 20020127495A1
• Filed: 03/12/2001
• Published: 09/12/2002
• Est. Priority Date: 03/12/2001
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Scherer, Axel
• Granted Patent: US 6,593,065 B2
• Time in Patent Office: Days
• US Class Current: 430/314
• CPC Class Codes: B81C 1/00404 Mask characterised by its size, orientation or shape
• CPC Class Codes: B81C 2201/0132 Dry etching, i.e. plasma etching, barrel etching, reactive ion etching [RIE], sputter etching or ion milling
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: G03F 7/16 Coating processes; Apparatus therefor applying coatings to base materials in general B05; applying photosensitive compositions to base for photographic purposes G03C1/74
• CPC Class Codes: Y10S 977/72 On an electrically conducting, semi-conducting, or semi-insulating substrate
• CPC Class Codes: Y10S 977/742 Carbon nanotubes, CNTs
• CPC Class Codes: Y10S 977/887 Nanoimprint lithography, i.e. nanostamp

Abstract

The invention is directed to a method of fabricating sub-wavelength features in semiconductors and insulators by starting with optical lithography patterns defined in a resist and then employing shadow-evaporation and directional etching to define nano-scale features. The directionality of this process is used together with a carefully defined photoresist mask to define an ion etching mask which allows the formation of very narrow trenches adjacent to the photoresist regions. Such narrow trenches can be used for electrical device isolation, for the definition of very small flow channels, and for the deposition of very narrow electrical contacts and wires.

Claims

1. A method for forming a nano-scale trench in a substrate comprising:

disposing a first masking layer having a thickness, d, on a surface of said substrate;

patterning said first masking layer;

disposing a second masking layer on said patterned first masking layer using angled deposition of said second masking layer to define an exposed trench window through said second masking layer by shadow deposition relative to said first masking layer;

defining said trench into said substrate through said exposed trench window; and

removing said first and second masking layers.

2. The method of claim 1 where defining said trench into said substrate through said exposed trench window comprising etching said trench into said substrate.

3. The method of claim 2 where etching said trench into said substrate comprises directionally etching said trench into said substrate.

4. The method of claim 3 where said substrate has a planar aspect and where directionally etching said trench into said substrate comprises etching said trench into said substrate in a direction substantially perpendicular to said planar aspect of said substrate.

5. The method of claim 1 where defining said trench into said substrate through said exposed trench window defines a trench window of width w, where w=d sin θ

, where θ

is the angle of incidence of said angled deposition of said second masking layer.

6. The method of claim 1 where disposing said second masking layer on said patterned first masking layer using angled deposition of said second masking layer comprises disposing said second masking layer by directional evaporation of material composing said second masking layer.

7. The method of claim 1 further comprising disposing a sealing layer over said trench to hermetically seal said trench to define a fluidic channel.

8. The method of claim 7 where disposing said sealing layer over said trench comprises disposing an elastomeric layer.

9. The method of claim 1 further comprising disposing a cantilever over said trench.

10. The method of claim 9 where disposing said cantilever over said trench comprises disposing a polymeric molecule over said trench.

11. The method of claim 10 where disposing said polymeric molecule over said trench comprises disposing a DNA molecule over said trench.

12. The method of claim 9 where disposing said cantilever over said trench comprises disposing a carbon nanotube over said trench.

13. The method of claim 9 further comprising disposing a conductive layer onto said cantilever to form a bridge to electrically connect adjacent contact regions separated by said trench.

14. The method of claim 13 further comprising forming said adjacent contact regions separated by said trench simultaneously with said bridge.

15. The method of claim 1 further comprising disposing a conductive layer into said trench to form a wire.

16. The method of claim 15 where said substrate has a planar surface and where disposing said conductive layer into said trench to form said wire comprises disposing said conductive layer onto said planar surface of said substrate and into said trench and then removing said conductive layer from said planar surface of said substrate.

18. The apparatus of claim 17 where said nano-scale trench is formed by disposing a first masking layer having a thickness, d, on a surface of said substrate, patterning said first masking layer, disposing a second masking layer on said patterned first masking layer using angled deposition of said second masking layer to define an exposed trench window through said second masking layer by shadow deposition relative to said first masking layer, defining said trench into said substrate through said exposed trench window, and removing said first and second masking layers.

19. The apparatus of claim 18 where said trench defined into said substrate through said exposed trench window is defined by etching said trench into said substrate.

20. The apparatus of claim 19 where said trench etched into said substrate is directionally etched said trench into said substrate.

21. The apparatus of claim 20 where said substrate has a planar aspect and where said directionally etched trench defined in said substrate is etched in a direction substantially perpendicular to said planar aspect of said substrate.

22. The apparatus of claim 17 where said trench defined into said substrate through said exposed trench window is defined through a trench window of width w, where w=d sin θ

, where θ

is the angle of incidence of said angled deposition of said second masking layer.

23. The apparatus of claim 17 where said trench is defined by disposing said second masking layer by directional evaporation of material composing said second masking layer.

24. The apparatus of claim 17 further comprising a sealing layer disposed over said trench to hermetically seal said trench to define a fluidic channel.

25. The apparatus of claim 24 where said sealing layer comprises an elastomeric layer.

26. The apparatus of claim 17 further comprising a cantilever disposed over said trench.

27. The apparatus of claim 26 where said cantilever comprises a polymeric molecule over said trench.

28. The apparatus of claim 27 where said polymeric molecule over said trench comprises a DNA molecule over said trench.

29. The apparatus of claim 26 where said cantilever over said trench comprises a carbon nanotube over said trench.

30. The apparatus of claim 26 further comprising adjacent contact regions separated by said trench and a conductive layer disposed onto said cantilever to form a bridge to electrically connect said adjacent contact regions separated by said trench.

31. The apparatus of claim 30 where said adjacent contact regions separated by said trench are formed simultaneously with said bridge.

32. The apparatus of claim 17 further comprising a conductive layer disposed into said trench to form a wire.

33. The apparatus of claim 32 where said substrate has a planar surface and where said conductive layer disposed into said trench to form said wire comprises a conductive layer disposed onto said planar surface of said substrate and into said trench which is then removed from said planar surface of said substrate to leave a portion of said conductive layer in said trench.

17. An apparatus comprising:

a substrate; and

a nano-scale trench defined into said substrate.