Alignment methods for imprint lithography

• US 6,916,584 B2
• Filed: 08/01/2002
• Issued: 07/12/2005
• Est. Priority Date: 08/01/2002
• Status: Expired due to Term

• Current Assignee: Mii Newco, Inc.
• Original Assignee: Molecular Imprints, Inc. (Canon Inc.)
• Inventors: Watts, Michael P. C., Voisin, Ronald D., Choi, Byung J., Sreenivasan, Sidlgata V
• Primary Examiner(s): Young, Christopher G.
• Application Number:
  US10/210,780
• Publication Number:
  US 20040021254A1
• Time in Patent Office: 1,076 Days
• Field of Search: 430/22, 430/302, 430/322, 264/494, 264/496
• US Class Current: 430/22
• CPC Class Codes: B29C 2035/0827 using UV radiation
• CPC Class Codes: B29C 2059/023 Microembossing
• CPC Class Codes: B29C 35/0888 using transparant moulds
• CPC Class Codes: B29C 59/002 Component parts, details or accessories; Auxiliary operations
• CPC Class Codes: B29C 59/02 by mechanical means, e.g. pressing B29C59/007 takes precedence; embossing expanded porous articles B29C44/5627
• CPC Class Codes: B29C 59/026 of layered or coated substantially flat surfaces
• 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: G03F 7/0002 Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
• CPC Class Codes: G03F 9/00 Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically G03F7/22 takes precedence; preparation of photographic masks G03F1/00; within photographic printing apparatus for making copies G03B27/00

Abstract

Described are methods for patterning a substrate by imprint lithography. Imprint lithography is a process in which a liquid is dispensed onto a substrate. A template is brought into contact with the liquid and the liquid is cured. The cured liquid includes an imprint of any patterns formed in the template. Alignment of the template with the substrate is performed prior to curing the liquid. Alignment of the template with the substrate includes rotational alignment of the template with respect to the substrate.

Claims

1. A method of forming a pattern on a substrate comprising:

obtaining an imprint lithography system, the imprint lithography system comprising;

a body;

a patterned template, wherein the patterned template is substantially transparent to an activating light, wherein the patterned template comprises a first template alignment mark and a second template alignment mark;

an imprint head coupled to the body, wherein the imprint head is configured to hold the patterned template proximate to the substrate during use; and

a motion stage coupled to the body, wherein the motion stage is configured to support the substrate, and wherein the motion stage is configured to move the substrate along a plane substantially parallel to the patterned template;

applying a predetermined amount of an activating light curable liquid to a portion of the substrate, wherein the portion of the substrate comprises a first substrate alignment mark and a second substrate alignment mark;

rotating the substrate with respect to the template such that the second template alignment mark is substantially aligned with the second substrate alignment mark when the first template alignment mark is aligned with the first substrate alignment mark;

applying the activating light to the activating light curable liquid, wherein the application of the activating light substantially cures the activating light curable liquid, defining a cured liquid; and

separating the template from the cured liquid.

2. The method of claim 1, wherein rotation of the substrate is performed such that the first template alignment mark remains substantially aligned with the first substrate alignment mark while the substrate is rotated.

3. The method of claim 1, wherein the patterned template comprises a first surface and a plurality of recesses formed in one or more patterning areas of the template extending from the first surface toward a second surface of the template, where the plurality of recesses define a plurality of features in the first surface of the patterned template.

4. The method of claim 3, wherein the patterned template comprises an outer region formed about a perimeter of one or more of the patterning areas, wherein a depth of the outer region is greater than a depth of the recesses.

5. The method of claim 1, wherein the patterned template comprises two or more patterning areas, each of the patterning areas comprising a plurality of recesses, and wherein the two or more patterning areas are separated from each other by a border, and wherein a depth of the border is greater than a depth of the recesses in the patterning areas.

6. The method of claim 1, further comprising adjusting a position of the template such that a patterning surface of the template is substantially parallel with a reference plane;

and adjusting the position of the substrate so that a surface of the substrate to be patterned is substantially parallel with the reference plane.

7. The method of claim 1, wherein separating the template from the cured liquid comprises moving the template and substrate into a substantially non-parallel orientation with respect to one another;

and moving the template and substrate apart from one another.

8. The method of claim 1, further comprising applying a separating light before separating the template from the cured liquid, wherein the separating light alters a chemical composition of a portion of the cured liquid such that an adhesion of the template to the cured liquid is reduced.

9. The method of claim 1, further comprising applying a separating light before separating the template from the cured liquid, wherein the separating light alters a chemical composition of a portion of the cured liquid such that a gas is released by the cured liquid near an interface of the template and the cured liquid.

10. The method of claim 1, further comprising providing an enclosure around at least the template and the substrate and inhibiting temperature variations greater than about 1.0°

C. within at least a portion of the enclosure.

11. The method of claim 1, wherein the activating light curable liquid does not entirely cover the portion of the substrate prior to positioning the patterned template and the substrate in a spaced relationship.

12. The method of claim 1, wherein the predetermined amount has a volume being less than or equal to a volume defined by non-recessed portions of the template, the portion of the substrate to be patterned, and a maximum fluid film thickness at which surface forces of a liquid-template interface and a liquid-substrate interface are sufficient to inhibit spreading of the liquid beyond a perimeter of the template.

13. The method of claim 1, wherein the predetermined amount has a volume being less than or equal to a volume defined by a volume of liquid required to substantially fill recesses of the patterned template, the portion of the substrate to be patterned, and a maximum fluid film thickness at which surface forces of a liquid-template interface and a liquid-substrate interface are sufficient to inhibit spreading of the liquid beyond a perimeter of the template.

14. The method of claim 1, further comprising applying a transfer layer to the substrate before applying the predetermined amount of the activating light curable liquid to the portion of the substrate, wherein the transfer layer etches at a different rate than an etch rate of the cured liquid under same etching conditions.

15. The method of claim 1, further comprising positioning the template and the substrate in a spaced-relation to each other with the template being coupled to the imprint head and the substrate keep being coupled to the motion stage, wherein the imprint head is located above the motion stage.

16. The method of claim 1, further comprising positioning the template and the substrate in a spaced-relation to each other with the template being pushed into the liquid and a position of the substrate being controlled so that a substantially parallel orientation of the template and substrate is maintained as the template pushes into the liquid.

17. The method of claim 1, wherein the activating light curable liquid has a viscosity of less than about 30 centipoise measured at 25°

C.

18. The method of claim 1, wherein the activating light curable liquid has a viscosity of less than about 5 centipoise measured at 25°

C.

19. The method of claim 1, wherein at least a portion of a first surface of the patterned template comprises a surface treatment layer.

20. The method of claim 1, wherein the template further comprises a surface treatment layer on at least a portion of a first surface, and wherein the surface treatment layer comprises a reaction product of an alkylsilane, a fluoroalkylsilane, or a fluoroalkyltrichlorosilane with water.

21. The method of claim 1, wherein the template further comprises a surface treatment layer on at least a portion of a first surface, and wherein the surface treatment layer comprises a reaction product of tridecafluoro-1,1,2,2-tetrahydrooctyl trichlorosilane with water.

22. The method of claim 1, wherein the template further comprises a surface treatment layer on at least a portion of a lower surface, and wherein the surface treatment layer reduces a surface free energy of the lower surface measured at 25°

C. to less than about 40 dynes/cm.

23. The method of claim 1, wherein the template comprises a first surface treatment layer on at least a portion of a lower surface, and a second surface treatment layer on recessed portions of the template, wherein the first and second surface treatment layers have different wetting characteristics with respect to the activating light curable liquid.

24. The method of claim 1, wherein the template further comprises a surface treatment layer on at least a portion of a first surface, and wherein the surface treatment layer comprises a monolayer.

25. The method of claim 1, wherein the patterned template is substantially transparent to the activating light.

26. The method of claim 1, wherein at least a portion of the template comprises silicon, silicon dioxide, silicon germanium carbon, gallium nitride, silicon germanium, sapphire, gallium arsenide, epitaxial silicon, poly-silicon, gate oxide, quartz, indium tin oxide, an oxide of silicon or a combination thereof.

27. The method of claim 1, wherein applying the activating light curable liquid to a portion of the substrate comprises dispensing the liquid with a fluid dispenser.

28. The method of claim 1, wherein applying the activating light curable liquid to a portion of the substrate comprises dispensing the liquid with a fluid dispenser such that a predetermined pattern of the activating light curable liquid is produced on the portion of the substrate.

29. The method of claim 1, wherein the activating light curable liquid comprises an ultraviolet light curable composition.

30. The method of claim 1, further comprising positioning the patterned template and the substrate in a spaced relationship such that the patterned template is positioned at a distance of less than about 500 nm from the substrate.

31. The method of claim 1, wherein the cured liquid comprises at least some features less than about 250 nm in size after the patterned template is separated from the cured liquid.

32. The method of claim 1, further comprising determining a distance between the template and the substrate by sensing a resistive force between the template and the applied activating light curable liquid.

33. The method of claim 1, wherein the substrate comprises silicon, silicon dioxide, gallium arsenide, silicon germanium, silicon germanium carbide or indium phosphide.

34. A method of forming a pattern on a substrate comprising:

obtaining an imprint lithography system, the imprint lithography system comprising;

a body;

a patterned template, wherein the patterned template is substantially transparent to an activating light, wherein the patterned template comprises a first template alignment mark and a second template alignment mark;

an imprint head coupled to the body, wherein the imprint head is configured to hold the patterned template proximate to the substrate during use;

a motion stage coupled to the body, wherein the motion stage is configured to support the imprint head, and wherein the motion stage is configured to move the imprint head along a plane substantially parallel to the substrate; and

a substrate support coupled to the body, wherein the substrate support is configured to hold the substrate proximate to the patterned template during use;

applying a predetermined amount of an activating light curable liquid to a portion of the substrate, wherein the portion of the substrate comprises a first substrate alignment mark and a second substrate alignment mark;

rotating the template with respect to the substrate such that the second template alignment mark is substantially aligned with the second substrate alignment mark when the first template alignment mark is aligned with the first substrate alignment mark;

applying the activating light to the activating light curable liquid, wherein the application of the activating light substantially cures the activating light curable liquid, defining a cured liquid; and

separating the template from the cured liquid.

35. A method of forming a pattern on a substrate comprising:

obtaining an imprint lithography system, the imprint lithography system comprising;

a body;

a patterned template, wherein the patterned template is substantially transparent to an activating light, wherein the patterned template comprises a first template alignment mark and a second template alignment mark;

an imprint head coupled to the body, wherein the imprint head is configured to hold the patterned template proximate to the substrate during use;

a motion stage coupled to the body, wherein the motion stage is configured to support the substrate, and wherein the motion stage is configured to move the substrate along a plane substantially parallel to the patterned template;

a first optical imaging device coupled to the imprint head;

a second optical imaging device coupled to the motion stage, and wherein the second optical imaging device is coupled to the motion stage such that the second optical imaging device and the substrate move together in a same direction during use; and

a system alignment target optically coupled to the first optical imaging device;

applying a predetermined amount of an activating light curable liquid to a portion of the substrate, wherein the portion of the substrate comprises a first substrate alignment mark and a second substrate alignment mark;

determining a position of the first template alignment mark and the second template alignment mark with respect to the system alignment target using the second optical imaging device and the motion stage;

determining a position of the first substrate alignment mark and the second substrate alignment mark with respect to the system alignment target using the first optical imaging device and the motion stage;

aligning the first template alignment mark with the first substrate alignment mark and the second template alignment mark with the second substrate alignment mark;

applying the activating light to the activating light curable liquid, wherein the application of the activating light substantially cures the activating light curable liquid, defining a cured liquid; and

separating the template from the cured liquid.

36. The method of claim 35, wherein the imprint lithography system further comprises a displacement detector coupled to the body, wherein a displacement detector is configured to determine the relative displacement of the motion stage during use.

37. The method of claim 36, wherein the displacement detector is an interferometer.

38. The method of claim 36, wherein the imprint lithography system further comprises a third optical imaging device optically coupled to the template, wherein the third optical imaging device is configured to obtain image data through at least two different portions of the template, and wherein the method further comprises:

adjusting the alignment of the first template alignment mark with the first substrate alignment mark using the third optical imaging device and the motion stage;

adjusting the alignment of the second template alignment mark with the second substrate alignment mark using the third optical imaging device and the motion stage.

39. A method of forming a pattern on a substrate comprising:

obtaining an imprint lithography system, the imprint lithography system comprising;

a body;

a patterned template, wherein the patterned template is substantially transparent to an activating light, wherein the patterned template comprises a first template alignment mark and a second template alignment mark;

an imprint head, wherein the imprint head is configured to hold the patterned template;

a motion stage coupled to the body, wherein the motion stage is configured to support the imprint head, and wherein the motion stage is configured to move the imprint head along a plane substantially parallel to the substrate,

a substrate support coupled to the body, wherein the substrate support is configured to hold the substrate proximate to the patterned template during use,

a first optical imaging device coupled to the motion stage, and wherein the first optical imaging device is coupled to the motion stage such that the first optical imaging device and the substrate move together in a same direction during use; and

a second optical imaging device coupled to the substrate support;

a system alignment target optically coupled to the first optical imaging device;

applying a predetermined amount of an activating light curable liquid to a portion of the substrate, wherein the portion of the substrate comprises a first substrate alignment mark and a second substrate alignment mark;

determining a position of the first template alignment mark and the second template alignment mark with respect to the system alignment target using the second optical imaging device and the motion stage;

determining a position of the first substrate alignment mark and the second substrate alignment mark with respect to the system alignment target using the first optical imaging device and the motion stage;

aligning the first template alignment mark with the first substrate alignment mark and the second template alignment mark with the second substrate alignment mark;

applying the activating light to the activating light curable liquid, wherein the application of the activating light substantially cures the activating light curable liquid, defining a cured liquid; and

separating the template from the cured liquid.

40. A method of forming a pattern on a substrate comprising:

obtaining an imprint lithography system, the imprint lithography system comprising;

a body;

a patterned template, wherein the patterned template is substantially transparent to an activating light, wherein the patterned template comprises a first template alignment mark and a second template alignment mark;

an imprint head coupled to the body, wherein the imprint head is configured to hold the patterned template proximate to the substrate during use;

a motion stage coupled to the body, wherein the motion stage is configured to support the substrate, and wherein the motion stage is configured to move the substrate along a plane substantially parallel to the patterned template;

a first optical imaging device coupled to the imprint head;

a second optical imaging device coupled to the motion stage, and wherein the second optical imaging device is coupled to the motion stage such that the optical imaging device and the substrate move together in a same direction during use; and

a system alignment target optically coupled to the first optical imaging device;

performing an alignment method at a plurality of fields on the substrate, wherein each of said plurality of fields comprises a first substrate alignment mark and a second substrate alignment mark, the alignment method comprising;

determining the a position of the first template alignment mark and the second template alignment mark with respect to the system alignment target using the second optical imaging device and the motion stage;

determining a position of the first substrate alignment mark and the second substrate alignment mark with respect to the system alignment target using the first optical imaging device and the motion stage; and

determining an alignment error between the template and the substrate;

determining an average alignment error as a function of the alignment error determined at said plurality of fields;

applying a predetermined amount of an activating light curable liquid to one of said plurality of fields;

aligning the template with said one of the plurality of fields using the average alignment error to determine the appropriate movement of the substrate;

applying the activating light to the the predetermined amount, wherein the application of the activating light substantially cures the predetermined amount, defining a cured liquid; and

separating the template from the cured liquid.

41. The method of claim 40, wherein the alignment method further comprises:

applying an additional predetermined amount of the activating light curable liquid to the remaining fields of the plurality of fields;

for the remaining field of the plurality of fields, aligning the first template alignment mark with the first substrate alignment mark and the second template alignment mark with the second substrate alignment mark; and

applying additional activating light to the additional predetermined amount, wherein the application of the additional activating light substantially cures the additional amount.

42. The method of claim 40, wherein a position of each field is predetermined, and wherein aligning the template with the field of the substrate further comprising moving the substrate based on the predetermined position of the field such that the template is positioned over the field.

43. The method of claim 42, wherein moving the substrate comprises monitoring movement of the substrate with an interferometer.

44. A method of forming a pattern on a substrate comprising:

obtaining an imprint lithography system, the imprint lithography system comprising;

a body;

a patterned template, wherein the patterned template is substantially transparent to an activating light, wherein the patterned template comprises a first template alignment mark and a second template alignment mark;

an imprint head coupled to the body, wherein the imprint head is configured to hold the patterned template proximate to the substrate during use;

a motion stage coupled to the body, wherein the motion stage is configured to support the substrate, and wherein the motion stage is configured to move the substrate along a plane substantially parallel to the patterned template;

a first optical imaging device coupled to the imprint head;

a second optical imaging device coupled to the motion stage, and wherein the second optical imaging device is coupled to the motion stage such that the second optical imaging device and the substrate move together in a same direction during use; and

a system alignment target optically coupled to the first optical imaging device;

applying a predetermined amount of an activating light curable liquid to a first portion of the substrate, wherein the first portion of the substrate comprises a first substrate alignment mark and a second substrate alignment mark, defining a cured liquid;

determining a position of the first template alignment mark and the second template alignment mark with respect to the system alignment target using the second optical imaging device;

determining a position of the first substrate alignment mark and the second substrate alignment mark with respect to the system alignment target using the first optical imaging device;

aligning the first template alignment mark with the first substrate alignment mark and the second template alignment mark with the second substrate alignment mark;

applying the activating light to the activating light curable liquid disposed on the first portion of the substrate, wherein the application of the activating light substantially cures the activating light curable liquid;

separating the template from the cured liquid on the first portion of the substrate;

applying an additional predetermined amount of the activating light curable liquid to a second portion of the substrate, wherein the second portion of the substrate comprises a third substrate alignment mark and a fourth substrate alignment mark;

determining a position of the third substrate alignment mark and the fourth substrate alignment mark with respect to the system alignment target using the first optical imaging device;

aligning the first template alignment mark with the third substrate alignment mark and the second template alignment mark with the fourth substrate alignment mark;

applying additional activating light to the additional predetermined amount, wherein the application of the additional activating light substantially cures the additional predetermined amount, defining additional cured liquid; and

separating the template from the additional cured liquid on the second portion of the substrate.

45. A method of forming a pattern on a substrate comprising:

obtaining an imprint lithography system, the imprint lithography system comprising;

a body;

a patterned template, wherein the patterned template is substantially transparent to an activating light, wherein the patterned template comprises a first template alignment mark and a second template alignment mark;

an imprint head coupled to the body, wherein the imprint head is configured to hold the patterned template proximate to the substrate during use;

a motion stage coupled to the body, wherein the motion stage is configured to support the substrate, and wherein the motion stage is configured to move the substrate along a plane substantially parallel to the patterned template; and

an optical imaging device optically coupled to the template, wherein the optical imaging device is configured to obtain image data through at least two different portions of the template;

applying a predetermined amount of an activating light curable liquid to a portion of the substrate;

wherein the portion of the substrate comprises a first substrate alignment mark and a second substrate alignment mark;

aligning the first template alignment mark with the first substrate alignment mark;

determining a position of the second template alignment mark with respect to the second substrate alignment mark with the optical imaging device;

aligning the first template alignment mark with the first substrate alignment mark and the second template alignment mark with the second substrate alignment mark;

applying the activating light to the activating light curable liquid, wherein the application of the activating light substantially cures the activating light curable liquid, defining a cured liquid; and

separating the template from the cured liquid.

46. The method of claim 45, wherein determining the position of the second template alignment mark with respect to the second substrate alignment mark with the optical imaging device comprises:

moving the optical imaging device within the imprint head to find the second substrate alignment mark;

moving the optical imaging device within the imprint head to find the second template alignment mark; and

determining a movement of the motion stage required to bring the second substrate alignment mark into alignment with the second template alignment mark.

47. A method of forming a pattern on a substrate comprising:

obtaining an imprint lithography system, the imprint lithography system comprising;

a body;

a patterned template, wherein the patterned template is substantially transparent to an activating light, wherein the patterned template comprises a first template alignment mark and a second template alignment mark;

an imprint head, wherein the imprint head is configured to hold the patterned template;

a motion stage coupled to the body, wherein the motion stage is configured to support the imprint head, and wherein the motion stage is configured to move the imprint head along a plane substantially parallel to the substrate;

a substrate support coupled to the body, wherein the substrate support is configured to hold the substrate proximate to the patterned template during use; and

an optical imaging device optically coupled to the template, wherein the optical imaging device is configured to obtain image data through at least two different portions of the template;

applying a predetermined amount of an activating light curable liquid to a portion of the substrate;

wherein the portion of the substrate comprises a first substrate alignment mark and a second substrate alignment mark;

aligning the first template alignment mark with the first substrate alignment mark;

determining a position of the second template alignment mark with respect to the second substrate alignment mark with the optical imaging device;

aligning the first template alignment mark with the first substrate alignment mark and the second template alignment mark with the second substrate alignment mark;

applying the activating light to the activating light curable liquid, wherein the application of the activating light substantially cures the activating light curable liquid, defining a cured liquid; and

separating the template from the cured liquid.

48. A method of forming a pattern on a substrate comprising:

obtaining an imprint lithography system, the imprint lithography system comprising;

a body;

a patterned template, wherein the patterned template is substantially transparent to an activating light, wherein the patterned template comprises a first template alignment mark and a second template alignment mark;

an imprint head coupled to the body, wherein the imprint head is configured to hold the patterned template proximate to the substrate during use;

a motion stage coupled to the body, wherein the motion stage is configured to support the substrate, and wherein the motion stage is configured to move the substrate along a plane substantially parallel to the patterned template; and

an optical imaging device optically coupled to the template, wherein the optical imaging device is configured to obtain image data through at least two different portions of the template;

performing an alignment method at two or more fields on the substrate, wherein each of said plurality of field comprises a first substrate alignment mark and a second substrate alignment mark, the alignment method comprising;

aligning the first template alignment mark with the first substrate alignment mark;

determining a position of the second template alignment mark with respect to the second substrate alignment mark with the optical imaging device;

aligning the first template alignment mark with the first substrate alignment mark and the second template alignment mark with the second substrate alignment mark; and

determining an alignment error between the template and the substrate;

determining an average alignment error as a function of the alignment errors determined at the plurality of fields;

applying a predetermined amount of an activating light curable liquid to a field of the substrate;

aligning the template with the one of the plurality of fields using the average alignment error;

applying the activating light to the predetermined amount, wherein the application of the activating light substantially cures the activating light curable liquid, defining a cured liquid; and

separating the template from the cured liquid.

49. A method of forming a pattern on a substrate comprising:

obtaining an imprint lithography system, the imprint lithography system comprising;

a body;

a patterned template, wherein the patterned template is substantially transparent to an activating light, wherein the patterned template comprises a first template alignment mark and a second template alignment mark;

an imprint head coupled to the body, wherein the imprint head is configured to hold the patterned template proximate to the substrate during use;

a motion stage coupled to the body, wherein the motion stage is configured to support the substrate, and wherein the motion stage is configured to move the substrate along a plane substantially parallel to the patterned template; and

an optical imaging device optically coupled to the template, wherein the optical imaging device is configured to obtain image data through at least two different portions of the template;

applying a predetermined amount of an activating light curable liquid to a portion of the substrate;

wherein the portion of the substrate comprises a first substrate alignment mark and a second substrate alignment mark;

aligning the first template alignment mark with the first substrate alignment mark;

determining a position of the second template alignment mark with respect to the second substrate alignment mark with the optical imaging device;

aligning the first template alignment mark with the first substrate alignment mark and the second template alignment mark with the second substrate alignment mark;

applying the activating light to the activating light curable liquid, wherein the application of the activating light substantially cures the activating light curable liquid, defining a first cured liquid;

separating the template from the first cured liquid;

applying an additional predetermined amount of activating light curable liquid to a second portion of the substrate, wherein the second portion of the substrate comprises a third substrate alignment mark and a fourth substrate alignment mark;

aligning the first template alignment mark with the third substrate alignment mark;

determining a position of the second template alignment mark with respect to the fourth substrate alignment mark with the optical imaging device;

aligning the first template alignment mark with the third substrate alignment mark and the second template alignment mark with the fourth substrate alignment mark;

applying an additional activating light to the predetermined amount, wherein the application of the additional activating light substantially cures the activating light curable liquid disposed on the second portion of the substrate, defining a second cured liquid; and

separating the template from the second cured liquid on the second portion of the substrate.