IMAGE SENSOR AND METHOD OF MANUFACTURING IMAGE SENSOR

• US 20190312072A1
• Filed: 03/14/2019
• Published: 10/10/2019
• Est. Priority Date: 04/04/2018
• Status: Active Grant

• Current Assignee: Korea Advanced Institute of Science and Technology, Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: CHO, Yang Ho, JEONG, Ki-Hun, NAM, Dong Kyung, KIM, Kisoo, JANG, Kyung-Won
• Granted Patent: US 10,916,575 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 3/0018 Reflow, i.e. characterized by the step of melting microstructures to form curved surfaces, e.g. manufacturing of moulds and surfaces for transfer etching
• CPC Class Codes: G02B 5/003 Light absorbing elements
• CPC Class Codes: G02B 7/003 Alignment of optical elements G02B7/001, G02B7/002 take precedence; for mirrors G02B7/1822
• CPC Class Codes: G02B 7/02 for lenses supports for magnifying lenses G02B25/002
• CPC Class Codes: H01L 27/14618 Containers
• CPC Class Codes: H01L 27/14623 Optical shielding
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14645 Colour imagers
• CPC Class Codes: H01L 27/14685 Process for coatings or optical elements

Abstract

An image sensor and a method of manufacturing the image sensor are provided. The image sensor includes a block layer including an absorption layer and a transparent layer, a lens element located below the block layer, and a sensing element located to face the lens element.

Claims

1. An image sensor comprising:

a block layer comprising an absorption layer and a transparent layer, and the block layer being configured to transmit light through an aperture formed in the absorption layer and the transparent layer; and

a lens element configured to transfer the light to a sensing element.

2. The image sensor of claim 1, wherein the sensing element is spaced apart from the lens element, and the sensing element is configured to receive the light passing through the aperture and the lens element.

3. The image sensor of claim 1, wherein the lens element is further configured to refract the light and to form a focal point on the sensing element.

4. The image sensor of claim 1, wherein the block layer is spaced apart by a focal length of the lens element from the sensing element.

5. The image sensor of claim 1, further comprising:

a transparent substrate configured to transmit light.

6. The image sensor of claim 1, wherein the aperture is located in the block layer to correspond to an arrangement of the lens element.

7. The image sensor of claim 1, further comprising:

a spacer configured to maintain an interval between the block layer and the sensing element.

8. The image sensor of claim 1, wherein the absorption layer and the transparent layer are alternately disposed in the block layer.

9. The image sensor of claim 1, wherein the absorption layer comprises a circular iris diaphragm centered on a point corresponding to the lens element.

10. The image sensor of claim 1, wherein

the absorption layer comprises an iris diaphragm with a first diameter centered on a point corresponding to the lens element, and

the block layer further comprises another absorption layer with another iris diaphragm with a second diameter different from the first diameter.

11. The image sensor of claim 1, wherein a diameter of the aperture gradually changes from one surface to another surface of the block layer.

12. The image sensor of claim 1, wherein the transparent layer is configured to transmit light in a wavelength band.

13. The image sensor of claim 1, wherein the block layer has a height based on a field of view (FOV).

14. The image sensor of claim 1, wherein a number of absorption layers stacked in the block layer is determined based on a field of view (FOV).

15. The image sensor of claim 1, wherein a diameter of the aperture is based on a quantity of the light, and the block layer is spaced apart from the sensing element by a focal length determined based on the quantity of the light.

16. The image sensor of claim 1, wherein the transparent layer comprises a transparent polymer configured to transmit light.

17. The image sensor of claim 1, wherein the absorption layer comprises a black matrix material configured to absorb light.

18. The image sensor of claim 1, wherein the block layer comprises a plurality of absorption layers, and a circular iris diaphragm formed in each of the plurality of absorption layers has a diameter that is determined based on a field of view (FOV) and a refractive index determined by the transparent layer and a transparent substrate disposed on the block layer.

19. The image sensor of claim 1, wherein

the lens element and the sensing element are arranged in a planar array pattern, and

the absorption layer comprises an iris diaphragm arranged based on the planar array pattern.

20. The image sensor of claim 5, wherein the transparent substrate is disposed on a first side of the block layer and the lens element is disposed on a second side of the block layer, opposing the first side.

21. A method of manufacturing an image sensor, the method comprising:

providing a transparent substrate;

providing a block layer comprising an absorption layer and a transparent layer; and

providing a lens element based on a pattern of apertures formed in the block layer.

22. A method of manufacturing an image sensor, the method comprising:

disposing a block layer comprising an absorption layer and a transparent layer on a transparent substrate; and

providing a lens element corresponding to a pattern of apertures formed in the block layer.

23. The method of manufacturing of claim 22, wherein the disposing of the block layer comprises:

coating the transparent substrate with an opaque polymer;

disposing a mask with the pattern on a portion of the opaque polymer;

emitting ultraviolet (UV) rays to the opaque polymer exposed through the pattern of the mask;

removing the portion of the opaque polymer covered with the mask;

coating a transparent layer comprising a negative photoresist over and between a remaining opaque polymer; and

exposing the transparent layer to UV rays.

24. The method of manufacturing of claim 23, further comprising increasing a bonding between the transparent layer and the remaining opaque polymer by performing a hydrophilic process.

25. The method of manufacturing of claim 23, wherein the mask comprises a circular mask with a grid pattern.

26. The method of manufacturing of claim 23, wherein the coating comprises a negative photoresist.

27. The method of manufacturing of claim 22, wherein the providing of the lens element comprises:

coating a thermoplastic polymer layer comprising a positive photoresist on the block layer;

disposing a mask with the pattern on a portion of the thermoplastic polymer layer;

exposing the thermoplastic polymer layer to ultraviolet (UV) rays through the pattern of the mask;

dissolving the thermoplastic polymer layer exposed to UV rays by a developer;

applying a hydrophobic coating to the patterned thermoplastic polymer layer; and

heating the coated thermoplastic polymer layer to form spherical lenses.

28. The method of manufacturing of claim 27, wherein the thermoplastic polymer layer comprises a transparent material moldable by heat.

29. An image sensor comprising:

a block layer comprising absorption layers and transparent layers alternatively stacked together;

an aperture formed in the absorption layers and the transparent layer to transfer light to a lens element; and

a sensing element spaced apart from the lens element, and being configured to receive the light from the lens element.

30. The image sensor of claim 29, wherein a diameter of the aperture gradually changes between two opposing surfaces of the block layer.

31. The image sensor of claim 29, wherein the aperture comprises circular openings in each of the absorption layers, and a diameter of the circular openings are based on a field of view (FOV) and a refractive index determined by the transparent layers and a transparent substrate disposed on the block layer.

32. The image sensor of claim 29, further comprising a spacer located at an outer boundary of the block layer and the sensing element, the spacer being configured to maintain an interval substantially equal to a focal length of the lens element between the block layer and the sensing element.