Structure and method for FPN reduction in imaging devices

• US 7,808,063 B2
• Filed: 05/26/2005
• Issued: 10/05/2010
• Est. Priority Date: 05/26/2005
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Boettiger, Ulrich C., Ladd, John
• Primary Examiner(s): NGUYEN, CUONG QUANG
• Application Number:
  US11/137,446
• Publication Number:
  US 20060268143A1
• Time in Patent Office: 1,958 Days
• Field of Search: 257431-466, 257/72, 257/E29.273, 257/E31, 257/E21
• US Class Current: 257/432
• CPC Class Codes: C23C 24/00 Coating starting from inorganic powder spraying of the coating material in molten state C23C4/00; solid state diffusion C23C8/00 - C23C12/00
• CPC Class Codes: C23C 28/00 Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
• CPC Class Codes: C23C 28/04 only coatings of inorganic non-metallic material
• CPC Class Codes: C23C 28/322 only coatings of metal elements only
• CPC Class Codes: C23C 28/34 including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
• CPC Class Codes: C23C 28/345 with at least one oxide layer
• CPC Class Codes: C23C 4/12 characterised by the method of spraying
• CPC Class Codes: C23C 4/18 After-treatment
• CPC Class Codes: H01L 27/1462 Coatings
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• 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 25/67 applied to fixed-pattern noise, e.g. non-uniformity of response

Abstract

Imaging devices having reduced fixed pattern noise are disclosed. The fixed pattern noise in the imaging devices is reduced by measuring and adjusting the spectral characteristics of the imager device on a pixel by pixel basis. The fixed pattern noise of the pixel cells are changed by modifying the absorption, reflectance, refractive index, shape, and/or micro structure of the material.

Claims

1. An imager comprising:

an array of pixel sensor cells comprising a plurality of pixel cells formed at an upper surface of a substrate;

a trim layer formed over said array;

a color filter layer formed over said array; and

an array of micro-lenses formed over said array, wherein spectral properties of said trim layer are selectively modifiable in portions of said trim layer corresponding to individual pixel cells.

2. The imager according to claim 1, wherein said trim layer is formed below said array of micro-lenses and said color filter layer.

3. The imager according to claim 1, wherein said trim layer is formed between said color filter layer and said array of micro-lenses.

4. The imager according to claim 1, wherein said trim layer is formed over said array of micro-lenses.

5. The imager according to claim 1, wherein said trim layer has a thickness of from about 1 angstrom to about 100 angstroms.

6. The imager according to claim 1, wherein said trim layer is a thin film.

7. The imager according to claim 6, wherein said thin film is a metal.

8. The imager according to claim 7, wherein said metal is selected from the group consisting of tungsten and aluminum.

9. The imager according to claim 6, wherein said thin film is a metal oxide.

10. The imager according to claim 6, wherein said thin film is amorphous carbon.

11. The imager according to claim 1, wherein said trim layer is modifiable to change the physical properties of the trim layer at selected locations.

12. The imager according to claim 11, wherein said physical properties are selected from the group consisting of absorption, reflectance, refractive index, shape, and micro structure.

13. The imager according to claim 1, wherein said spectral properties of said trim layer are modifiable to reduce fixed pattern noise of said imager.

14. An processor system comprising:

an array of pixel sensor cells comprising a plurality of pixel cells formed at an upper surface of a substrate;

a trim layer formed over said array;

a color filter layer formed over said array;

an array of micro-lenses formed over said array, wherein spectral properties of said trim layer are selectively modifiable in portions of said trim layer corresponding to individual pixel cells to reduce fixed pattern noise of said imager;

an

a processor for receiving and processing data representing the image.

15. The processor system of claim 14, wherein said arrays and said processor are formed on a single substrate.

16. The processor system according to claim 14, wherein said trim layer is formed below said array of micro-lenses and said color filter layer.

17. The processor system according to claim 14, wherein said trim layer is formed between said color filter layer and said array of micro-lenses.

18. The processor system according to claim 14, wherein said trim layer is formed over said array of micro-lenses.

19. The processor system according to claim 14, wherein said trim layer is a thin film.

20. The processor system according to claim 19, wherein said thin film is a metal.

21. The processor system according to claim 20, wherein said metal is selected from the group consisting of tungsten and aluminum.

22. The processor system according to claim 19, wherein said thin film is a metal oxide.

23. The processor system according to claim 19, wherein said thin film is amorphous carbon.

24. The processor system according to claim 19, wherein said trim layer is modifiable to change the physical properties of the trim layer.

25. The processor system according to claim 24, wherein said physical properties are selected from the group consisting of absorption, reflectance, refractive index, shape, and micro structure.

26. An imager comprising:

an array of pixel sensor cells comprising a plurality of pixel cells formed at an upper surface of a substrate;

a trim layer formed over said array;

a color filter layer formed over said array; and

an array of micro-lenses formed over said array, wherein said trim layer has been spectrally modified in portions of said trim layer corresponding to individual pixel cells.