CN115799282A - Image sensor with a plurality of pixels - Google Patents

Abstract

The invention provides an image sensor.A second color filter array of a single color is arranged at the periphery of a first color filter array of multiple colors, the single color is one of the multiple colors, and the thickness slowly-changing areas of other colors are removed or reduced, so that the utilization area of a substrate is increased and the cost waste is avoided. One or more grooves are formed in the light blocking structure, and the grooves are filled with the second color filter material to reduce the falling height of the top surface of the second color filter array, so that the monochromatic thickness gradual change area is reduced. A multicolored third color filter array is disposed between the first and second color filter arrays with the top surfaces of the second and third color filter arrays gradually decreasing in a direction toward the first color filter array, taking into account process tolerances and increasing process window.

Description

Image Sensor

technical field

The invention relates to the technical field of semiconductors, in particular to an image sensor.

Background technique

Image sensors are the core components of camera equipment, functional devices capable of sensing radiation (such as optical radiation, including but not limited to visible light, infrared rays, ultraviolet rays, etc.) and generating electronic signals, and are widely used in various electronic products .

An image sensor includes a pixel area and a peripheral circuit area, both of which perform different functions and have different internal structures, so their heights may also be different. For example, the peripheral circuit region is a region for processing photocharges generated in the pixel region and generating electrical signals that can realize an optical image of a subject. The incident light not only irradiates on the pixel area, but also irradiates on the peripheral circuit area, wherein the photocharge generated in the peripheral circuit area may form the noise of the electrical signal, and it is necessary to use a light-shielding structure to block the peripheral circuit area to prevent the photocharge in the peripheral circuit area. Noise is generated in the above-mentioned peripheral circuit area, and a step is formed between the two to cause a height difference, or a step height.

Due to the height difference, the surface of the color filter at the step will have a certain slope, resulting in poor uniformity of filling the color filter around the pixel area, and an additional buffer of a certain length is required, making this part of the area difficult to be used. , affecting the integration of the image sensor.

Therefore, how to reduce the cost and adopt a simple manufacturing process to solve the above-mentioned problems in the prior art is necessary.

Contents of the invention

The object of the present invention is to provide an image sensor, which can reduce the invalid area of the image sensor and increase the utilization area of the substrate through layout optimization.

Based on the above considerations, the present invention provides an image sensor, including: a multicolor first color filter array and a monochrome second color filter array around it, the monochrome being one of the multicolor .

Preferably, the second color filters are arranged with gaps between them.

Preferably, it further includes: a grid-shaped grid structure arranged between adjacent first color filters.

Preferably, the grid structure is also arranged between adjacent second color filters.

Preferably, the single color is the latest color among the multiple colors.

Preferably, the multicolor includes green, red and blue.

Preferably, the top surface of the first color filter array is not higher than the top surface of the second color filter array.

Preferably, along the direction toward the first color filter array, the top surface of the second color filter array descends gradually.

Preferably, it also includes: a multicolor third color filter array disposed between the first color filter array and the second color filter array, and the second and third color filter arrays The top surface gradually declines.

Preferably, it further includes: a light blocking structure disposed on the periphery of the second color filter array and covered with the second color filter.

Preferably, one or more grooves are provided in the light blocking structure, and the second color filter also covers the grooves.

Preferably, the grooves are arranged in rows and/or columns.

Preferably, the groove is arranged concentrically with the light blocking structure.

Preferably, the groove runs through or does not run through the light-shielding structure.

Preferably, the light corresponding to the first and second color filters is selected from infrared light, red light, green light, blue light and ultraviolet light.

In the present invention, a multi-color first color filter array is provided in the pixel area, and a monochromatic second color filter array is provided in the buffer zone, and the monochromatic color is one of the multi-colors. The thickness of the color changes gradually, thereby reducing the invalid area (for example, the buffer zone) in the layout of the image sensor, increasing the utilization area of the substrate and avoiding cost waste.

Further, one or more grooves are provided in the light-shielding structure, and the material of the second color filter fills the grooves to reduce the drop height of the top surface of the second color filter array, thereby reducing the The single color gradient area.

Further, considering the process error and increasing the process window, the multi-color third color filter array is arranged between the first color filter array and the second color filter array, and along the In the direction of the color filter array, the top surfaces of the second and third color filters gradually descend.

Description of drawings

Other features, objects and advantages of the present invention will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

FIG. 1 shows a schematic plan view of an image sensor in the prior art;

Fig. 2 shows a partial sectional view along A-A' in Fig. 1;

FIG. 3 shows a schematic plan view of an image sensor according to Embodiment 1 of the present invention;

Fig. 4 shows a partial cross-sectional view along B-B' in Fig. 3;

FIG. 5 shows a schematic plan view of an image sensor according to Embodiment 2 of the present invention;

FIG. 6 shows a schematic partial cross-sectional view of an image sensor according to Embodiment 2 of the present invention;

FIG. 7 shows a schematic plan view of an image sensor according to Embodiment 3 of the present invention;

FIG. 8 shows a partial cross-sectional schematic diagram of an image sensor according to Embodiment 3 of the present invention;

FIG. 9 shows a schematic plan view of an image sensor according to Embodiment 4 of the present invention;

FIG. 10 shows a schematic partial cross-sectional view of an image sensor according to Embodiment 4 of the present invention;

FIG. 11 shows a schematic plan view of an image sensor according to Embodiment 5 of the present invention.

In the drawings, the same or similar reference numerals denote the same or similar means (modules) or steps throughout different views.

Detailed ways

In order to make the content of the present invention clearer and easier to understand, the content of the present invention will be further described below in conjunction with the accompanying drawings. Of course, the present invention is not limited to this specific embodiment, and general replacements known to those skilled in the art are also covered within the protection scope of the present invention.

It should be noted that, in the following specific embodiments, when describing the embodiments of the present invention in detail, in order to clearly show the structure of the present invention for the convenience of description, the structures in the drawings are not drawn according to the general scale, and are drawn Partial magnification, deformation and simplification are included, therefore, it should be avoided to be interpreted as a limitation of the present invention.

FIG. 1 shows a schematic plan view of an image sensor in the prior art; FIG. 2 shows a partial cross-sectional view along A-A′ in FIG. 1 .

Please refer to FIG. 1 and FIG. 2 in conjunction. The image sensor may include a pixel area 101 and a peripheral circuit area 104, wherein the pixel area 101 has several pixel units (not shown) for sensing radiation, and the peripheral circuit area 104 has a A structure (not shown) that performs other processing.

A color filter and a microlens (not shown) may be sequentially arranged above each pixel unit, and the pixel unit is in an array form, and may include: a red pixel for generating photocharges; green pixels for generating photocharges corresponding to incident light in the green spectral domain; and blue pixels for generating photocharges corresponding to incident light in the blue spectral region. The color filters formed on the pixel units correspond to form a multicolor color filter array, so that each of the pixel units can be used to sense light radiation in different frequency bands.

As shown in Figure 2, the color filters include a green color filter 1131 for sensing green light, a red color filter 1132 for sensing red light, and a blue color filter 1133 for sensing blue light . The image sensor 100 further includes a grid-like metal grid 112 disposed between adjacent pixel units to isolate adjacent color filters.

The green color filter 1131, the red color filter 1132 and the blue color filter 1133 are arranged periodically, and are all arranged on the substrate 100 of the pixel area 101 and the buffer area 103, for example, Two pixel units for sensing green light, one pixel unit for sensing red light, and one pixel unit for sensing blue light form a Bayer arrangement.

The image sensor may also adopt an RGBW color filter arrangement, that is, the image sensor includes at least one pixel unit group, and each pixel unit group includes four pixel units arranged in a two-by-two array.

Wherein, one pixel unit is used for sensing green light, and the green color filter 1131 is provided. One pixel unit is used for sensing red light, and the red color filter 1132 is provided. One pixel unit is used for sensing blue light, and a blue color filter 1133 is provided. In addition, there is also a pixel unit for sensing white light, and a white color filter (not shown) for passing white light is provided. , or, no color filter is provided.

The microlens is an optical element, which may include a refracting microlens (not shown) based on the refraction theory of light, a diffractive microlens (not shown) based on the diffraction theory of light, and the like. Generally speaking, due to the processing of incident light, the microlenses in the image sensor need to be arranged on a flat surface to perform well. For example, microlenses can be installed directly above the color filters. In this case, the upper surfaces of the color filters need to be sufficiently flat.

As shown in FIG. 1 , the light blocking structure 111 is disposed on the substrate 100 of the peripheral circuit area 104 around the pixel area 101 to form a height difference with the substrate 100 of the pixel area 101 . The following will be described in detail in conjunction with the case of the light-shielding structure. However, those skilled in the art should understand that there may be various reasons for the height difference between the peripheral circuit area and the pixel area, and it is not limited to the light-shielding structure.

As shown in FIG. 2 , when filling the openings of the metal grids to form color filters, a red color filter layer (not shown) or a green color filter layer is respectively formed on the substrate 100 by using a spin-coating process. layer (not shown) or blue color filter layer (not shown), the red color filter layer and/or the green color filter layer and/or the blue color filter layer are also covered on the light blocking structure 111 , and drop down to the buffer zone 103 along the top surface of the light-shielding structure, and the top surfaces of the color filters located in the buffer zone 103 generate slopes accordingly.

Along the direction towards the pixel area 101, the red color filter layer or the green color filter layer or the blue color filter layer has a thickness gradually changing area in the buffer zone, and the thickness between each other is from high to high. Slow down. Then, the red color filter layer or the green color filter layer or the blue color filter layer is patterned to form the green color filter 1131 , the red color filter 1132 or the blue color filter 1133 .

If the microlenses are formed on the color filter of the buffer zone 103 with a slope, the microlenses will also have a slope correspondingly, which is not conducive to image display. Therefore, the buffer zone 103 is not suitable for setting pixel units. becomes an invalid area. Therefore, the multi-color color filter array corresponding to the buffer zone 103 cannot be used, resulting in a waste of a part of the substrate area, and the limited area of the pixel region leads to a waste of cost.

In order to solve the above-mentioned problems in the prior art, the present invention provides an image sensor, the pixel area is provided with a multicolor first color filter array, and the buffer zone is provided with a monochrome second color filter array, and the monochrome As one of the multi-colors, by removing or reducing the gradually changing thickness regions of other colors, thereby reducing the invalid region (for example, the buffer zone) in the layout of the image sensor, increasing the utilization area of the substrate and avoiding cost waste.

The light corresponding to the first color filter and the second color filter may be selected from: infrared light, red light, green light, blue light and ultraviolet light.

FIG. 3 shows a schematic plan view of an image sensor according to Embodiment 1 of the present invention; FIG. 4 shows a partial cross-sectional view along B-B′ in FIG. 3 .

As shown in FIG. 4 , in the first embodiment, the first color filter 113 includes the green color filter 1131 , the red color filter 1132 and the blue color filter 1133 . The metal grid 112 is disposed between adjacent first color filters 113 . According to the order of formation, the color of the second color filter (ie, the single color) is the latest one among the multiple colors.

Those skilled in the art will understand that the image sensor according to the embodiments of the present disclosure may include any number of pixel unit groups, and each pixel unit group may include any number of one or more pixel units arranged in any manner. The color, arrangement, quantity and size of the first color filter may depend on the resolution of the image sensor, which is not limited herein.

Please refer to FIG. 3 and FIG. 4 in combination, the top surfaces of the first color filters 113 located in the pixel area 101 are flush with each other or the height difference between them does not exceed a first preset value. Along the direction away from the pixel area 101, a buffer area 103 and a peripheral circuit area 104 are arranged in sequence from near to far, and the height difference between the second color filters located in the buffer area 103 does not exceed a second preset value, The first preset value is smaller than the second preset value.

As shown in FIG. 4 , in the first embodiment, the single color is blue as an example, and the other colors are red and green. That is to say, the second color filter is the blue color filter 1133 .

Before forming the blue color filter 1133, when the red color filter layer and the green color filter layer are respectively patterned to form the red color filter 1132 and the green color filter 1131, at least the red color filter layer located in the buffer zone 103 is removed And the green color filter layer, so that there is a large area of blank space on the buffer zone 103 . When the blue color filter layer is spin-coated, due to the fluidity of the material, when the blue color filter layer descends from the light-shielding structure 111 to the substrate 100 , its top surface can quickly descend to a predetermined height.

There is only the blue color filter 1133 on the buffer zone 103, and by removing or reducing the gradually changing thickness regions of other colors, the monochrome gradually changing thickness region is reduced, that is, the buffer zone 103 is reduced. The lateral dimension increases the effective use area of the substrate 100 .

Each of the color filter layers may be formed by any of the following coating techniques, including but not limited to spin coating, brush coating, spray coating, electrostatic spray coating, 3D printing and any combination thereof. Those skilled in the art understand that the above process steps for forming each of the color filter layers are optional and not limiting, and each of the color filter layers of the present invention can be formed by any suitable process steps.

In this embodiment, a dummy region 102 is provided between the pixel region 101 and the buffer region 103 in consideration of the process error and increasing the process window, and the dummy region 102 is provided with a plurality of third color filters to form multiple A third color filter array of the same color, the third color filter may include the green color filter 1131 , the red color filter 1132 and the blue color filter 1133 .

The multi-color third color filter array is arranged between the first color filter array and the second color filter array, and along the direction toward the pixel region 101, the second and second color filter arrays The top surface of the three-color filter array descends gradually.

FIG. 5 shows a schematic plan view of an image sensor according to Embodiment 2 of the present invention; FIG. 6 shows a schematic partial cross-sectional view of an image sensor according to Embodiment 2 of the present invention.

Please refer to FIG. 5 and FIG. 6 in conjunction, the second color filters are disposed on the buffer zone 103 with gaps between them. That is to say, except for the second color filter, the buffer area 103 is not provided with a metal grid 112 for isolating the adjacent second color filter, so as to further increase the peripheral circuit area 104 And the blank area between the pixel area 101, so that the top surface of the second color filter (such as the blue color filter) can be lowered to a preset height more quickly, so as to shorten the lateral size of the buffer zone 103 .

FIG. 7 shows a schematic plan view of an image sensor according to Embodiment 3 of the present invention; FIG. 8 shows a schematic partial cross-sectional view of an image sensor according to Embodiment 3 of the present invention.

Please refer to FIG. 7 and FIG. 8 , the light blocking structure 111 is provided with one or more grooves 114 , and the second color filter also covers the grooves 114 .

The groove 114 extends inwardly from the top surface of the light blocking structure 111 , and the material of the second color filter layer has fluidity and fills the groove 114 .

Along the direction toward the pixel area 101, the top surface of the material of the second color filter on the light blocking structure 111 first descends from a first height, and then rises to a second height, after that, the first height The materials of the two color filters drop from the light blocking structure 111 to the substrate 100 . The second height is lower than the first height, so that the drop height of the top surface of the second color filter array is reduced to shorten the lateral dimension of the buffer zone.

FIG. 9 shows a schematic plan view of an image sensor according to Embodiment 4 of the present invention; FIG. 10 shows a schematic partial cross-sectional view of an image sensor according to Embodiment 4 of the present invention; FIG. 11 shows an image of Embodiment 5 of the present invention A schematic plan view of the sensor.

The grooves 114 can be arranged in the light blocking structure 111 in rows and/or columns.

Please refer to FIG. 9 and FIG. 10 in conjunction, the groove 114 may be concentrically disposed with the light blocking structure 111 to surround the pixel area in a ring shape.

In the fourth embodiment, as shown in FIG. 10 , on the basis that no metal grid 112 is provided on the buffer zone 103, the groove 114 may or may not penetrate the light-shielding structure 111. By setting the groove 114 to adjust the drop height of the top surface of the second color filter array, so as to flexibly adjust the lateral size of the buffer zone 103 .

In the fifth embodiment, as shown in FIG. 11 , the groove 114 may pass through the light-shielding structure 111, and a plurality of the grooves 114 are arranged in the light-shielding structure 111 in rows and/or columns, so as to and reducing the thickness gradient area of the second color filter of the single color. In addition, the shape, position and size of the groove 114 can also be flexibly configured.

In the present invention, a multi-color first color filter array is provided in the pixel area, and a monochrome second color filter array is provided in the buffer zone. The thickness of other colors gradually changes, so as to reduce the invalid area (for example, the buffer zone) in the layout of the image sensor, improve the utilization area of the substrate and avoid cost waste.

Further, one or more grooves are provided in the light-shielding structure, and the material of the second color filter fills the grooves to reduce the drop height of the top surface of the second color filter array, thereby reducing the The single color gradient area.

Further, considering the process error and increasing the process window, the multi-color third color filter array is arranged between the first color filter array and the second color filter array, and along the In the direction of the color filter array, the top surfaces of the second and third color filters gradually descend.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all respects as exemplary and not restrictive. Furthermore, it is obvious that the word "comprising" does not exclude other elements and steps, and the word "a" does not exclude the plural. A plurality of elements recited in device claims may also be embodied by one element. The words first, second, etc. are used to denote names and do not imply any particular order.

Claims (15)

1. An image sensor, comprising: a first color filter array of multiple colors and a second color filter array of a single color at the periphery thereof, the single color being one of the multiple colors.

2. The image sensor as in claim 1, wherein the second color filters are disposed with a gap therebetween.

3. The image sensor of claim 1, further comprising: and a grid-shaped grating structure arranged between the adjacent first color filters.

4. The image sensor of claim 3, wherein the grid structure is further disposed between adjacent ones of the second color filters.

5. The image sensor of claim 1, wherein the single color is a color of the multi-color that is formed latest.

6. The image sensor of claim 5, wherein the multiple colors include green, red, and blue.

7. The image sensor of claim 1, wherein a top surface of the first color filter array is no higher than a top surface of the second color filter array.

8. The image sensor of claim 7, wherein the top surface of the second color filter array is tapered in a direction toward the first color filter array.

9. The image sensor of claim 8, further comprising: and a third multicolor color filter array arranged between the first color filter array and the second color filter array, wherein the top surfaces of the second and third color filter arrays gradually descend.

10. The image sensor of any of claims 1 to 9, further comprising: and the light blocking structure is arranged at the periphery of the second color filter array and covered with the second color filter.

11. The image sensor as in claim 10, wherein one or more recesses are formed in the light blocking structure, the second color filter further covering the recesses.

12. The image sensor of claim 11, wherein the grooves are arranged in rows and/or columns.

13. The image sensor of claim 11, wherein the recess is disposed concentrically with the light blocking structure.

14. The image sensor of claim 11, wherein the recess penetrates or does not penetrate the light blocking structure.

15. The image sensor of claim 1, wherein the light corresponding to the first and second color filters is selected from the group consisting of: infrared light, red light, green light, blue light, and ultraviolet light.

Images