Image sensor having micro lenses arranged in different periods

• US 10,644,050 B2
• Filed: 12/14/2018
• Issued: 05/05/2020
• Est. Priority Date: 02/19/2018
• Status: Active Grant

• Current Assignee: SK Hynix Inc.
• Original Assignee: SK Hynix Inc.
• Inventors: Cho, Sung-Wook, Cho, Min-Su
• Primary Examiner(s): Blum, David S
• Application Number:
  US16/220,141
• Publication Number:
  US 20190259796A1
• Time in Patent Office: 508 Days
• Field of Search: 257432
• CPC Class Codes: H01L 27/14603 Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
• CPC Class Codes: H01L 27/14605 Structural or functional details relating to the position of the pixel elements, e.g. smaller pixel elements in the center of the imager compared to pixel elements at the periphery
• CPC Class Codes: H01L 27/14607 Geometry of the photosensitive area
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14623 Optical shielding
• 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
• CPC Class Codes: H04N 25/76 Addressed sensors, e.g. MOS or CMOS sensors

Abstract

An image sensor including a pixel area and a peripheral area surrounding the pixel area is described. The pixel area may include first micro lenses. The peripheral area may include second micro lenses. The first micro lenses may be arranged with a first period. The second micro lenses may be arranged with a second period different from the first period.

Claims

1. An image sensor comprising:

a pixel area structured to include photosensing pixels that detect light of a scene to produce pixel signals representing the detected scene including spatial information of the detected scene; and

a peripheral area structured to surround the pixel area and to shield light,

wherein the pixel area includes first micro lenses positioned over the photosensing pixels in a periodic array with a first spatial period, and the peripheral area includes second micro lenses in a periodic array with a second, different spatial period.

2. The image sensor according to claim 1, wherein each of the first micro lenses and each of the second micro lenses have a same micro lens design including a lens shape, a lens width, or a lens thickness.

3. The image sensor according to claim 1,

wherein the first period is the same as a horizontal width or diameter of the first micro lenses, and

wherein the second period is greater than a horizontal width or diameter of the second micro lenses.

4. The image sensor according to claim 3, wherein the second period is integer times the first period.

5. The image sensor according to claim 1,

wherein the first micro lenses are arranged in the pixel area in a horizontal direction and a vertical direction, and

wherein the second micro lenses are arranged in the peripheral area in the horizontal direction or the vertical direction.

6. The image sensor according to claim 1,

wherein the first micro lenses have a first pitch in the pixel area, and

wherein the second micro lenses have a second pitch in the peripheral area.

7. The image sensor according to claim 1,

wherein the first micro lenses have a first pattern density in the pixel area,

wherein the second micro lenses have a second pattern density in the peripheral area, and

wherein the first pattern density is higher than the second pattern density.

8. The image sensor according to claim 1,

wherein the pixel area comprises:

an inner pixel area; and

an outer pixel area surrounding the inner pixel area,

wherein the inner pixel area comprises;

inner pixel photodiodes formed in a substrate;

inner pixel grid patterns disposed over a top surface of the substrate;

inner pixel color filters disposed in spaces between the inner pixel grid patterns;

an inner pixel overcoating layer disposed over the inner pixel color filters; and

inner pixel micro lenses disposed over the inner pixel overcoating layer,

wherein the outer pixel area comprises;

outer pixel photodiodes formed in the substrate;

outer pixel grid patterns disposed over the top surface of the substrate;

outer pixel color filters disposed in spaces between the outer pixel grid patterns;

an outer pixel overcoating layer disposed over the outer pixel color filters; and

outer pixel micro lenses disposed over the outer pixel overcoating layer, and

wherein the first micro lenses include the inner pixel micro lenses and the outer pixel micro lenses.

9. The image sensor according to claim 1,

wherein the peripheral area includes an inner peripheral area and an outer peripheral area surrounding the inner peripheral area,

wherein each of the inner peripheral area and the outer peripheral area comprises:

a shield layer disposed over the top surface of a substrate;

a peripheral overcoating layer disposed over the shield layer; and

peripheral micro lenses disposed over the peripheral overcoating layer, and

wherein the second micro lenses include the peripheral micro lenses.

10. The image sensor according to claim 9,

wherein the inner peripheral area further comprises peripheral color filters which are formed over the shield layer,

wherein the outer peripheral area further comprises an over color filter which is formed over the shield layer, and

wherein the over color filter has a vertical thickness thicker than the peripheral color filters.

11. The image sensor according to claim 10, wherein the over color filter includes a blue color filter.

12. The image sensor according to claim 10,

where the peripheral color filters are formed in the outer peripheral area, and

wherein the over color filter is formed between the peripheral color filters.

13. The image sensor according to claim 9,

wherein the shield layer has a flat board shape or a plate shape, and includes a bottom shield layer and a top shield layer, and

wherein the bottom shield layer includes a dielectric material, and the top shield layer includes a metal.

14. An image sensor comprising:

a first pixel area structured to include first pixels each operable to sense light and to produce a pixel signal representing sensed light; and

a peripheral area surrounding the first pixel area,

the first pixel area comprising;

first pixel grid patterns that are disposed over a substrate and are formed by the first pixels;

first pixel color filters formed in spaces between the first pixel grid patterns;

a first pixel overcoating layer over the first pixel color filters; and

first pixel micro lenses disposed over the first pixel overcoating layer,

the peripheral area comprising;

a shield layer disposed over the substrate;

a peripheral overcoating layer disposed over the shield layer; and

peripheral micro lenses disposed over the peripheral overcoating layer,

wherein the first pixel micro lenses are arranged in a first periodic pattern with a first spatial period, and

wherein the peripheral micro lenses are arranged in a second periodic pattern with a second spatial period different from the first spatial period.

15. The image sensor according to claim 14, further comprising:

a second pixel area surrounding the first pixel area between the first pixel area and the peripheral area,

wherein the second pixel area comprises;

second pixel grid patterns disposed over the substrate;

second pixel color filters formed in spaces between the second pixel grid patterns;

a second pixel overcoating layer formed over the second pixel color filters; and

second pixel micro lenses over the second pixel overcoating layer.

16. The image sensor according to claim 15,

wherein the second pixel area includes an inner second pixel area which is close to the first pixel area and an outer second pixel area which is close to the peripheral area, and

wherein the second pixel micro lenses are arranged with the first period in the inner second pixel area and are arranged with the second period in the outer second pixel area.

17. The image sensor according to claim 14,

wherein the peripheral area includes an inner peripheral area which is close to the first pixel area and an outer peripheral area which surrounds the inner peripheral area, and

wherein the outer peripheral area further comprises an over color filter which is disposed between the shield layer and the peripheral overcoating layer.

18. The image sensor according to claim 17, wherein the inner peripheral area further comprises peripheral photodiodes which are formed in the substrate and peripheral color filters which are formed over the shield layer.

19. The image sensor according to claim 14,

wherein the first pixel micro lenses and the peripheral micro lenses have a same specification including at least one of a shape, a width, or a thickness, and

wherein a pattern density of the first pixel micro lenses in the first pixel area is higher than a pattern density of the peripheral micro lenses in the peripheral area.

20. The image sensor according to claim 14, wherein the second period is integer times the first period.

21. An image sensor comprising:

an inner pixel area which detects light of a scene to produce pixel signals representing the detected scene including spatial information of the detected scene and including first micro lenses arranged with a first period;

an outer pixel area located to surround the inner pixel area and including second micro lenses arranged with a second period;

a peripheral area located to surround the outer pixel area and including third micro lenses arranged with a third period;

wherein two of the first period, the second period, and the third period are different from each other.

22. The image sensor of claim 21, wherein the first period is different from the third period.

23. The image sensor of claim 21, wherein the first period is different from the second period.

24. The image sensor of claim 21, wherein the outer pixel area includes a first outer pixel area and a second outer pixel area surrounding the first outer pixel area and the second micro lenses are arranged in the first outer pixel area or the second outer pixel area, or both of the first outer pixel area and the second outer pixel area.