Image sensor and preparation method thereof

Abstract

The invention provides an image sensor and a preparation method thereof. The image sensor comprises a pixel array, a color film layer and a plurality of micro lenses. The invention relates to the field of semiconductors. Through a new pixel array, the problem of color accuracy in a traditional Bayer array interpolation algorithm is solved, the image sensor provided by the invention is simple and compact in arrangement, and can increase more light incoming quantity, so that the image sensor can still obtain a clear image when the illumination is relatively dark or the exposure time is relatively short, and the image sensor can be widely applied to the field of image processing. The quality of the image sensor is improved. The invention is mainly used for realizing the color image shooting of the CCD or CMOS sensor.

Description

Technical Field

[0001] The present invention relates to the field of semiconductors. Background Art

[0002] The Bayer array is one of the main technologies for realizing color image capture with CCD or CMOS sensors. It simulates the sensitivity of the human eye to color, uses a color filter array of 1 red, 2 green, and 1 blue to filter light, and converts grayscale graphics into color images by performing 9 operations in a 2×2 matrix, and finally generates a color graphic. However, the chromaticity loss of green pixels is 50%, and the chromaticity loss of red and blue pixels is 75%. It is incomplete sampling and must be demosaiced through interpolation. This calculated color inevitably causes some color accuracy problems, such as moiré and false color. Summary of the invention

[0003] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide an image sensor and a method for manufacturing the same, so as to improve the color accuracy, thereby improving the quality of the image sensor and reducing moiré and false color.

[0004] To solve the above technical problems, the present invention is implemented through the following technical solutions.

[0005] The present invention provides an image sensor, comprising at least:

[0006] A pixel array, comprising a plurality of photodiodes arranged in a predetermined array;

[0007] A color filter layer, arranged on the pixel array;

[0008] A plurality of micro lenses are arranged on the color filter layer according to the preset array, and the center of each lens is aligned with the center of one of the photodiodes.

[0009] In one embodiment of the present invention, the coverage area of ​​each of the micro lenses is the area occupied by each of the photodiodes.

[0010] In an embodiment of the present invention, the color filter layer includes a plurality of color filter layers, and the plurality of color filter layers are arranged between each of the lenses and the pixel array.

[0011] The present invention also provides a method for preparing an image sensor, which comprises at least the following steps:

[0012] Providing a pixel array, the pixel array comprising a plurality of photodiodes arranged in a preset array;

[0013] forming a color filter layer on the pixel array;

[0014] A plurality of micro lenses are formed on the color filter layer according to the preset array, and the center of each lens is aligned with the center of one of the photodiodes.

[0015] In summary, the present invention provides an image sensor and a method for manufacturing the same, which can improve color accuracy, thereby improving the quality of the image sensor and reducing moiré and false colors.

[0016] Of course, any method of implementing the present invention does not necessarily need to achieve all of the advantages mentioned above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0018] Figure 1 FIG. 4 is a schematic diagram of a pixel array according to an embodiment of the present invention.

[0019] Figure 2 FIG. 4 is a schematic diagram of forming a metal grid according to an embodiment of the present invention.

[0020] Figure 3 FIG. 4 is a schematic diagram of forming a color filter layer in one embodiment of the present invention.

[0021] Figure 4 FIG. 4 is a schematic diagram of forming a microlens according to an embodiment of the present invention.

[0022] Figure 5 Schematic diagram showing the relationship between a non-edge pixel and its adjacent pixels in an embodiment of the present invention.

[0023] Figure 6 Schematic diagram showing the relationship between an edge pixel and its adjacent pixels in an embodiment of the present invention.

[0024] Description of labels:

[0025] 100, pixel array; 101, photodiode; 200, metal grid area; 300, color filter layer; 400, triangular microlens array; DETAILED DESCRIPTION

[0026] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0027] It should be understood that the present invention can be implemented in different forms and should not be interpreted as limited to the embodiments set forth herein. On the contrary, these embodiments are provided to make the disclosure thorough and complete and to fully convey the scope of the present invention to those skilled in the art.

[0028] The technical solution of the present invention is further described in detail below in conjunction with the embodiments and drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] See also Figure 1 to Figure 2 As shown, in one embodiment of the present invention, a metal grid area 200 is formed on the pixel array 100. The metal grid area 200 is provided to provide support for the color filter layer 300 that is subsequently provided.

[0030] See also Figures 2 to 3 As shown, in one embodiment of the present invention, after the metal mesh area 200 is formed, the color filter layer 300 is embedded in the metal mesh area 200. The present invention does not limit the thickness and color of the color filter layer 300, which can be selected according to actual needs. In this embodiment, by providing the color filter layer 300, light of a preset wavelength can be filtered out and injected into the photodiode 101, and the photodiode 101 then converts the received optical signal into an electrical signal.

[0031] See also Figure 3 to Figure 4 As shown, in one embodiment of the present invention, after the color filter layer 300 is formed, a micro lens 400 is formed on the metal grid 200 including the color filter layer 300. The lens 400 is, for example, a plurality of lenses 400, which are arranged on the color filter layer 300 according to a preset array, and the preset array of the plurality of lenses 400 is the same as the distribution array of the photodiodes 101 in the pixel array 100.

[0032] See also Figure 1As shown, the present invention provides a method for preparing an image sensor. In this embodiment, a pixel array 100 is first provided. The pixel array 100 includes a plurality of photodiodes 101 arranged in a preset array. In the pixel array 100, each photodiode 101 has the same size. In order to achieve a wide dynamic range, photodiodes 101 of different sizes need to be designed in the pixel array 100. In this embodiment, the photodiodes 101 in the pixel array 100 have the same size, and a wide dynamic range can be achieved without specially designing photodiodes 101 of different sizes, thereby reducing the processing difficulty of the pixel array 100 and shortening the processing cycle and processing cost. Moreover, in the pixel array 100 composed of photodiodes 101 of different sizes, some photodiodes 101 are smaller in size, while the photodiodes 101 of the same size in this embodiment have a larger full well capacity, thereby achieving a wider dynamic range.

[0033] See also Figure 4 As shown, the present invention provides an image sensor, which includes, for example, a pixel array 100, a color filter layer 300, a plurality of micro lenses 400, etc. Among them, the pixel array 100 includes a plurality of photodiodes 101, the color filter layer 300 is arranged on the pixel array 100, and the plurality of micro lenses 400 are arranged on the color filter layer 300. The image sensor provided by the present invention has a simple and compact arrangement, which can increase the amount of light entering, so that the image sensor can still obtain a clear image when the light is dark or the exposure time is short, thereby improving the quality of the image sensor.

[0034] See also Figures 5 and 6 As shown, the present invention provides the relationship between non-edge pixels and adjacent pixels and the relationship between edge pixels and adjacent pixels, which can optimize the algorithm, improve color accuracy, and thus improve the quality of the image sensor.

[0035] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An image sensor, characterized in that: At least: A pixel array, comprising a plurality of photodiodes arranged in a predetermined array; A color filter layer, arranged on the pixel array; A plurality of micro lenses are arranged on the color filter layer according to the preset array.

2. The image sensor according to claim 1, characterized in that The coverage area of ​​each lens is the area occupied by the photodiode.

3. The image sensor according to claim 1, characterized in that The color filter layer is arranged between each of the lenses and the pixel array.

4. A method for preparing an image sensor, characterized in that: At least the following steps are included: Providing a pixel array, the pixel array comprising a plurality of photodiodes arranged in a preset array; forming a color filter layer on the pixel array; A plurality of micro lenses are formed on the color filter layer according to the preset array, and the center of each lens is aligned with the center of one of the photodiodes.

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