Versatile process for precision nanoscale manufacturing

Patent metadata

Field	Value
Publication number	US-9987653-B2
Application number	US-201615293884-A
Country	US
Kind code	B2
Filing date	Oct 14, 2016
Priority date	Oct 15, 2015
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

A method for depositing thin films using a nominally curved substrate. Drops of a pre-cursor liquid organic material are dispensed at a plurality of locations on a nominally curved substrate by one or more inkjets. A superstrate is brought down on the dispensed drops to close the gap between the superstrate and the substrate thereby allowing the drops to form a contiguous film captured between the substrate and the superstrate. A non-equilibrium transient state of the superstrate, the contiguous film and the substrate is enabled to occur after a duration of time. The contiguous film is then cured to solidify it into a solid. The solid is separated from the superstrate thereby leaving a polymer film on the substrate. In this manner, such a technique for film deposition has the film thickness range, resolution and variation required to be applicable for a broad spectrum of applications.

First claim

The invention claimed is:

1. A method for depositing thin films, the method comprising:
dispensing drops of a pre-cursor liquid organic material at a plurality of locations on a nominally non-planar substrate by one or more inkjets;
closing a gap bringing between a superstrate and said substrate thereby allowing said drops to form a contiguous film captured between said substrate and said superstrate;
enabling a non-equilibrium transient state of said superstrate, said contiguous film and said substrate to occur after a duration of time by allowing said superstrate, said contiguous film and said substrate to evolve to a time pre-determined by an inverse optimization routine prior to said dispensing of said drops of said pre-cursor liquid organic material;
curing said contiguous film to solidify it into a solid; and
separating said superstrate from said solid thereby leaving a polymer film on said substrate.

2. The method as recited in claim 1 , wherein said substrate comprises one of the following: a spherical surface, an aspherical surface, a toric surface, a cylindrical surface, a conic section and a freeform surface.

3. The method as recited in claim 1 further comprising:
virtually dividing said substrate into two-dimensional grains, wherein each of said two-dimensional grains has a peak-valley difference not exceeding an optimal jetting range of an inkjet, wherein each of said two-dimensional grains is treated as an individual substrate by said inkjet on which said inkjet dispenses a drop pattern that corresponds to a two-dimensional grain.

4. The method as recited in claim 3 further comprising:
using a coordinated relative motion of said substrate and said inkjet in order to not exceed said optimum jetting range of said inkjet and to stitch said inkjetted drop pattern corresponding to each of said two-dimensional grains with inkjetted drop patterns of adjacent two-dimensional grains to create a single desired inkjet pattern on said substrate.

5. The method as recited in claim 1 , wherein said plurality of locations on said nominally non-planar substrate are derived from an inverse optimization framework.

6. The method as recited in claim 1 further comprising:
aligning coordinate frames between said substrate and a reference surface to ensure said drops of said pre-cursor liquid organic material are dispensed at correct locations.

7. The method as recited in claim 1 , wherein a back surface of said substrate or said superstrate is held by a chuck over an area which is less than an entirety of an area of said back surface.

8. The method as recited in claim 1 , wherein a back surface of said substrate or said superstrate is held by a chuck over an area that is substantially an entirety of an area of said back surface.

9. The method as recited in claim 1 , wherein a back surface of said substrate or said superstrate is curved, wherein chucking of said substrate or said superstrate is performed using one of the following: using a chuck with a complementary profile to that of a back side of said substrate or said superstrate, chucking said back surface in regions that are coplanar, adding a planar back surface and chucking said planar back surface.

10. The method as recited in claim 1 , wherein said substrate or said superstrate is chucked on a back side using a multi-region chuck, wherein one or more regions of said chuck are engaging vacuum and one or more other regions of said chuck are pressurizing said substrate or said superstrate.

11. The method as recited in claim 1 , wherein said superstrate is a roll-to-roll film with appropriate tension control to achieve optimal bending rigidity without encountering tensile yield or buckling failure, wherein said tension is controlled to be high during drop merging and controlled to be low after said drop merging.

12. The method as recited in claim 11 , wherein said roll-to-roll film is advanced to bring in clean superstrates to minimize propagation of contamination defects from one substrate to another.

13. The method as recited in claim 1 , wherein said superstrate has a complementary shape to that of said substrate.

14. The method as recited in claim 1 , wherein said superstrate is composed of a thin film attached to or coated on a thicker backing.

15. The method as recited in claim 14 , wherein said thin film is attached to said thicker backing which does not extend over an entire area of said thin film.

16. The method as recited in claim 1 , wherein an inkjet of said one or more inkjets consists of a platform with multiple nozzles that can be individually adjusted in a vertical direction.

17. The method as recited in claim 1 , wherein handles are attached to a superstrate chuck to assist in separation of a non-planar superstrate from a non-planar substrate.

18. The method as recited in claim 1 , wherein said superstrate comprises a sacrificial film that is removed using photochemical ablation.

19. The method as recited in claim 1 , wherein a liquid volume dispensed compensates for parasitics comprising one of the following: an evaporation profile of the liquid prior to it being captured between said substrate and said superstrate, shrinking effects across said contiguous film caused during solidifying, and non-uniform etch signatures coming from an etcher during post-processing.

20. The method as recited in claim 1 , wherein pre-equilibrium transients create a film thickness profile whose volume distribution is a function of a volume distribution of fluid drops dispensed on said substrate.

21. The method as recited in claim 1 , wherein said substrate is discretized into grains, wherein a location and volume of drops dispensed in each grain are obtained by using an inverse optimization to minimize an error between a function of an actual film thickness profile and a function of a desired film thickness profile.

22. The method as recited in claim 1 , wherein a location and volume of drops dispensed on said substrate are obtained by using an inverse optimization to minimize an error between a function of an actual film thickness profile and a function of a desired film thickness profile.

23. The method as recited in claim 22 , wherein said inverse optimization is augmented with a functional optimization routine to minimize an error between the desired and actual functional performance.

24. The method as recited in claim 22 , wherein said inverse optimization comprises discrete variables associated with drop volumes or drop locations.

25. The method as recited in claim 22 , wherein said inverse optimization comprises an influence of gravity in the presence of non-planar surfaces.

26. The method as recited in claim 25 , wherein said influence of gravity is minimized by having a thickness of said superstrate being below a threshold.

27. The method as recited in claim 25 , wherein said influence of gravity is minimized by rotating a superstrate-fluid-substrate sandwich at a frequency high enough to overcome gravity-induced visco-capillary filling.

28. The method as recited in claim 22 further comprising:
using a linearized model as part of said inverse optimization.

29. The method as recited in claim 1 , wherein said polymer film is solidified by light or thermal curing.

30. The method as recited in claim 1 , wherein said polymer film is subject to etching to allow a t

Assignees

• Univ Texas

Inventors

• Sreenivasan Sidlgata V
• Singhal Shrawan

Classifications

• B81C1/0038 Primary

  Processes for creating layers of materials not provided for in groups B81C1/00357 - B81C1/00373 · CPC title

• B05D3/067

  Curing or cross-linking the coating · CPC title

• B05D1/42 Primary

  by non-rotary members · CPC title

• B05C5/027

  Coating heads with several outlets, e.g. aligned transversally to the moving direction of a web to be coated (B05C5/0254 takes precedence) · CPC title

• B41J2/01

  Ink jet · CPC title