Microlenses including a plurality of mutually adhered layers of optically transmissive material and systems including the same

• US 7,488,618 B2
• Filed: 01/20/2006
• Issued: 02/10/2009
• Est. Priority Date: 09/02/2004
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Benson, Peter A., Watkins, Charles M., Farnworth, Warren M., Wood, Alan G.
• Primary Examiner(s): Lee; Calvin
• Application Number:
  US11/336,567
• Publication Number:
  US 20060134827A1
• Time in Patent Office: 1,117 Days
• Field of Search: 438110-113, 438124-127, 438/57, 438/64, 438 69- 72, 257709-711, 257787-795, 257/95, 257/98, 257/118, 257/233, 257/E27, 257/E31, 257/E31.115
• US Class Current: 438/72
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: H01L 21/56 Encapsulations, e.g. encapsulation layers, coatings
• CPC Class Codes: H01L 2224/04105 Bonding areas formed on an encapsulation of the semiconductor or solid-state body, e.g. bonding areas on chip-scale packages
• CPC Class Codes: H01L 2224/20 Structure, shape, material or disposition of high density interconnect preforms
• CPC Class Codes: H01L 23/3128 the substrate having spherical bumps for external connection
• CPC Class Codes: H01L 27/14618 Containers
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14685 Process for coatings or optical elements
• CPC Class Codes: H01L 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01027 Cobalt [Co]
• CPC Class Codes: H01L 2924/01046 Palladium [Pd]
• CPC Class Codes: H01L 2924/12041 LED

Abstract

Microlenses for directing radiation toward a sensor of an imaging device include a plurality of mutually adhered layers of cured optically transmissive material. Systems include at least one microprocessor and a substrate including an array of microlenses formed thereon in electrical communication with the at least one microprocessor. At least one microlens in the array includes a plurality of mutually adhered layers of cured optically transmissive material.

Claims

1. A method of fabricating a microlens, comprising:

forming a first layer of optically transmissive material;

forming at least one additional layer of the optically transmissive material over the first layer of the optically transmissive material; and

forming at least a portion of a generally curved surface of a microlens from at least a portion of a sidewall of each of the first layer of the optically transmissive material and the at least one additional layer of the optically transmissive material.

2. The method of claim 1, further comprising orienting the at least a portion of the generally curved surface of the microlens to direct radiation toward a sensor of an imaging device.

3. The method of claim 2, wherein each of forming the first layer of optically transmissive material and forming the at least one additional layer of the optically transmissive material comprises depositing the optically transmissive material using a stamp over selected areas of a substrate.

4. The method of claim 2, wherein each of forming the first layer of optically transmissive material and forming the at least one additional layer of the optically transmissive material comprises depositing the optically transmissive material using a printer head over selected areas of a substrate.

5. The method of claim 1, further comprising:

forming a plurality of mutually adhered layers of the optically transmissive material over the first layer of the optically transmissive material; and

forming the at least a portion of the generally curved surface of the microlens from at least a portion of a sidewall of each layer of the plurality of mutually adhered layers of the optically transmissive material.

6. The method of claim 5, further comprising smoothing the at least a portion of the generally curved surface of the microlens.

7. The method of claim 6, wherein smoothing the at least a portion of the generally curved surface of the microlens comprises at least one of:

heating the microlens to a temperature exceeding a glass transition temperature of the optically transmissive material;

machining the at least a portion of the generally curved surface of the microlens with a laser beam; and

exposing the at least a portion of the generally curved surface of the microlens to a solvent.

8. The method of claim 1, wherein each of forming the first layer of optically transmissive material and forming the at least one additional layer of the optically transmissive material comprises:

disposing a flowable, uncured optically transmissive material over a surface of a substrate;

selectively curing at least one region of the flowable, uncured optically transmissive material; and

removing any remaining uncured optically transmissive material from the substrate.

9. The method of claim 8, wherein selectively curing at least one region of the flowable, uncured optically transmissive material comprises directing a laser beam at the at least one region of the flowable, uncured optically transmissive material.

10. The method of claim 1, wherein each of forming the first layer of optically transmissive material and forming the at least one additional layer of the optically transmissive material comprises depositing the optically transmissive material using an aerosol stream over selected areas of a substrate.

11. The method of claim 1, wherein each of forming the first layer of optically transmissive material and forming the at least one additional layer of the optically transmissive material comprises depositing the optically transmissive material using a micropen over selected areas of a substrate.

13. The microlens of claim 1, wherein the at least a portion of the generally curved surface exhibits stair-stepping.

14. The microlens of claim 1, wherein the optically transmissive material comprises at least one of a photopolymer and a thermoplastic.

15. The microlens of claim 1, wherein the at least a portion of the at least one generally curved surface is substantially smooth.

16. The microlens of claim 1, wherein the imaging device further comprises sea an array of sensors.

12. A microlens comprising:

a volume of optically transmissive material having at least one generally curved surface, the volume comprising a plurality of mutually adhered layers of the optically transmissive material, at least a portion of the at least one generally curved surface of the volume of optically transmissive material comprising sidewalls of at least some of the plurality of mutually adhered layers of the optically transmissive material.

17. A system, comprising:

an array of photosensor; and

array of microlenses formed over the array of photosensors, at least one microlens of the array of microlenses comprising a volume of optically transmissive material having at least one generally curved surface, the volume comprising a plurality of mutually adhered layers of cured optically transmissive material, at least a portion of the at least one generally curved surface of the volume of optically transmissive material comprising sidewalls of at least some layers of the plurality of mutually adhered layers of the optically transmissive material.

18. The system of claim 17, wherein the at least a portion of the at least one generally curved surface exhibits stair-stepping.

19. The system of claim 17, wherein the optically transmissive material comprises at least one of a photopolymer and a thermoplastic.

20. The system of claim 17, wherein the at least a portion of the at least one generally curved surface is substantially smooth.