Image sensor and manufacturing method thereof

Abstract

The invention provides an image sensor and a manufacturing method thereof, the image sensor comprises: a filter layer, the filter layer comprises a first filter layer and a second filter layer, the first filter layer comprises a first light-transmitting material layer and a second light-transmitting material layer, the refractive index of the second light-transmitting material layer is greater than that of the first light-transmitting material layer, and the refractive index of the second light-transmitting material layer is greater than that of the second light-transmitting material layer; the first filter layer comprises a first area, a second area, a third area and a fourth area, the first filter layer located in the first area, the second area, the third area and the fourth area has different optical thicknesses, and the first area allows light rays of other colors except the light rays of the first color in the mixed color light rays to pass through; the second area or the fourth area allows other color light rays except the second color light rays in the mixed color light rays to pass through, and the third area allows other color light rays except the third color light rays in the mixed color light rays to pass through; the second filter layer is located above the first area, the second area, the third area and the fourth area. According to the technical scheme, the quantum efficiency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor integrated circuit manufacturing, and in particular to an image sensor and a manufacturing method thereof. Background Art

[0002] At present, all CMOS image sensors use R, G, and B organic materials as filter layers to achieve color distinction between different pixel units, and then combine the data of adjacent pixel units through algorithms to achieve color restoration, which is commonly known as the Bayer Pattern. A single-color filter layer only transmits a single color of light and absorbs light of other colors, resulting in more photon loss.

[0003] Therefore, how to reduce the loss of photons and improve quantum efficiency is an urgent problem that needs to be solved. Summary of the invention

[0004] The object of the present invention is to provide an image sensor and a method for manufacturing the same, which greatly improves the quantum efficiency.

[0005] To achieve the above object, the present invention provides an image sensor, comprising:

[0006] substrate;

[0007] A filter layer is formed on the substrate, the filter layer includes a first filter layer and a second filter layer, the first filter layer includes a first light-transmitting material layer and a second light-transmitting material layer, the first light-transmitting material layer is closer to the substrate than the second light-transmitting material layer, the refractive index of the second light-transmitting material layer is greater than the refractive index of the first light-transmitting material layer, the first filter layer includes a first area, a second area, a third area, and a fourth area, the first area, the second area, the third area, and the fourth area are adjacent to each other in sequence, the first filter layer located in the first area, the second area, the third area, and the fourth area has different optical thicknesses, the first area allows other color light except the first color light in the mixed color light to pass through, the second area or the fourth area allows other color light except the second color light in the mixed color light to pass through, and the third area allows other color light except the third color light in the mixed color light to pass through; the second filter layer is located above the first area, the second area, the third area, and the fourth area.

[0008] Optionally, the first filter layer includes the first light-transmitting material layer and the second light-transmitting material layer that are periodically alternately stacked, the first light-transmitting material layer in each period is closer to the substrate than the second light-transmitting material layer, and the number of periods of the periodic alternate stacking is greater than or equal to 3.

[0009] Optionally, the second filter layer includes the fourth light-transmitting material layer and the fifth light-transmitting material layer that are periodically and alternately stacked, the refractive index of the fourth light-transmitting material layer is greater than the refractive index of the fifth light-transmitting material layer, the fourth light-transmitting material layer in each period is closer to the substrate than the fifth light-transmitting material layer, and the number of periods of the periodic alternating stacking is greater than or equal to 3;

[0010] A third light-transmitting material layer is formed between the fourth light-transmitting material layer and the second light-transmitting material layer, and the refractive index of the third light-transmitting material layer is smaller than the refractive indexes of the second light-transmitting material layer and the fourth light-transmitting material layer.

[0011] Optionally, the image sensor further includes:

[0012] A first metal grid is formed in the first filter layer and the second filter layer, and the first metal grid is used to isolate adjacent filter layer sublayers from each other. The filter layer sublayers include the first filter layer in the first area, the second area, the third area, and the fourth area, and the second filter layer above the first filter layer corresponding to the first area, the second area, the third area, and the fourth area.

[0013] Optionally, the image sensor further includes:

[0014] A pixel array is arranged in the substrate, pixels in the pixel array are formed correspondingly below the first area, the second area, the third area, and the fourth area, and adjacent pixels are isolated by an isolation structure.

[0015] Optionally,

[0016] The first area allows other color lights except the first color light in the mixed color light to pass through so that the pixels below the first area can calculate and output the complementary color of the first color light through an algorithm;

[0017] The second area or the fourth area allows other color lights except the second color light in the mixed color light to pass through so that the pixels below the second area or the fourth area can calculate and output the complementary color of the second color light through an algorithm;

[0018] The third area allows other color lights except the third color light in the mixed color light to pass through so that the pixels below the third area can output the complementary color of the third color light through algorithm calculation.

[0019] Optionally,

[0020] The first color light that has not entered the first area enters at least one of the second area, the third area, and the fourth area;

[0021] The second color light that has not entered the second area or the fourth area enters at least one of the first area and the third area;

[0022] The third color light that has not entered the third area enters at least one of the first area, the second area, and the fourth area.

[0023] The present invention also provides a method for manufacturing an image sensor, comprising:

[0024] providing a substrate;

[0025] A filter layer is formed on the substrate, the filter layer includes a first filter layer and a second filter layer, the first filter layer includes a first light-transmitting material layer and a second light-transmitting material layer, the first light-transmitting material layer is closer to the substrate than the second light-transmitting material layer, the refractive index of the second light-transmitting material layer is greater than the refractive index of the first light-transmitting material layer, the first filter layer includes a first region, a second region, a third region, and a fourth region, the first region, the second region, the third region, and the fourth region are adjacent to each other in sequence, the first filter layer located in the first region, the second region, the third region, and the fourth region has different optical thicknesses, the first region allows other color light except the first color light in the mixed color light to pass through, the second region or the fourth region allows other color light except the second color light in the mixed color light to pass through, and the third region allows other color light except the third color light in the mixed color light to pass through; the second filter layer is located above the first region, the second region, the third region, and the fourth region.

[0026] Optionally, the first filter layer includes the first light-transmitting material layer and the second light-transmitting material layer that are periodically alternately stacked, the first light-transmitting material layer in each period is closer to the substrate than the second light-transmitting material layer, and the number of periods of the periodic alternate stacking is greater than or equal to 3.

[0027] Optionally, the second filter layer includes the fourth light-transmitting material layer and the fifth light-transmitting material layer that are periodically and alternately stacked, the refractive index of the fourth light-transmitting material layer is greater than the refractive index of the fifth light-transmitting material layer, the fourth light-transmitting material layer in each period is closer to the substrate than the fifth light-transmitting material layer, and the number of periods of the periodic alternating stacking is greater than or equal to 3;

[0028] A third light-transmitting material layer is formed between the fourth light-transmitting material layer and the second light-transmitting material layer, and the refractive index of the third light-transmitting material layer is smaller than the refractive indexes of the second light-transmitting material layer and the fourth light-transmitting material layer.

[0029] Optionally, the method for manufacturing the image sensor further includes:

[0030] A first metal grid is formed in the first filter layer and the second filter layer, and the first metal grid is used to isolate adjacent filter layer sub-layers from each other. The filter layer sub-layers include the first filter layer in the first area, the second area, the third area, and the fourth area, and the second filter layer above the first filter layer corresponding to the first area, the second area, the third area, and the fourth area.

[0031] Optionally, before forming the filter layer on the substrate, the method for manufacturing the image sensor further includes:

[0032] A pixel array is formed, and the array is arranged in the substrate. Pixels in the pixel array are correspondingly formed below the first area, the second area, the third area, and the fourth area, and adjacent pixels are isolated by an isolation structure.

[0033] Optionally,

[0034] The first area allows other color lights except the first color light in the mixed color light to pass through so that the pixels below the first area can calculate and output the complementary color of the first color light through an algorithm;

[0035] The second area or the fourth area allows other color lights except the second color light in the mixed color light to pass through so that the pixels below the second area or the fourth area can calculate and output the complementary color of the second color light through an algorithm;

[0036] The third area allows other color lights except the third color light in the mixed color light to pass through so that the pixels below the third area can output the complementary color of the third color light through algorithm calculation.

[0037] Optionally,

[0038] The first color light that has not entered the first area enters at least one of the second area, the third area, and the fourth area;

[0039] The second color light that has not entered the second area or the fourth area enters at least one of the first area and the third area;

[0040] The third color light that has not entered the third area enters at least one of the first area, the second area, and the fourth area.

[0041] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0042] 1. The image sensor of the present invention comprises a filter layer, which is formed on the substrate. The filter layer comprises a first filter layer and a second filter layer. The first filter layer comprises a first light-transmitting material layer and a second light-transmitting material layer. The first light-transmitting material layer is closer to the substrate than the second light-transmitting material layer. The refractive index of the second light-transmitting material layer is greater than the refractive index of the first light-transmitting material layer. The first filter layer comprises a first region, a second region, a third region, and a fourth region. The first region, the second region, the third region, and the fourth region are adjacent to each other in sequence. The first filter layer located in the first region, the second region, the third region, and the fourth region has different optical thicknesses. The first region allows other color light rays except the first color light rays in the mixed color light rays to pass through. The second region or the fourth region allows other color light rays except the second color light rays in the mixed color light rays to pass through. The third region allows other color light rays except the third color light rays in the mixed color light rays to pass through. The second filter layer is located above the first region, the second region, the third region, and the fourth region, so that the quantum efficiency is greatly improved.

[0043] 2. A method for manufacturing an image sensor of the present invention, wherein a filter layer is formed on the substrate, wherein the filter layer comprises a first filter layer and a second filter layer, wherein the first filter layer comprises a first light-transmitting material layer and a second light-transmitting material layer, wherein the first light-transmitting material layer is closer to the substrate than the second light-transmitting material layer, wherein the refractive index of the second light-transmitting material layer is greater than the refractive index of the first light-transmitting material layer, wherein the first filter layer comprises a first region, a second region, a third region, and a fourth region, wherein the first region, the second region, the third region, and the fourth region are adjacent to each other in sequence, wherein the first filter layer located in the first region, the second region, the third region, and the fourth region has different optical thicknesses, wherein the first region allows other color light rays except the first color light rays in the mixed color light rays to pass through, wherein the second region or the fourth region allows other color light rays except the second color light rays in the mixed color light rays to pass through, and wherein the third region allows other color light rays except the third color light rays in the mixed color light rays to pass through; wherein the second filter layer is located above the first region, the second region, the third region, and the fourth region, thereby greatly improving the quantum efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1is a schematic top view of a first filter layer according to an embodiment of the present invention;

[0045] Figure 2 is a schematic top view of a second filter layer according to an embodiment of the present invention;

[0046] Figure 3 yes Figure 1 The first filter layer and Figure 2 The schematic cross-sectional view of the second filter layer along the AA' direction is shown;

[0047] Figure 4 yes Figure 1 The first filter layer and Figure 2 The schematic cross-sectional view of the second filter layer along the BB' direction is shown;

[0048] Figure 5 is a schematic diagram of enhancing reflection of the first filter layer according to an embodiment of the present invention;

[0049] Figure 6 is a schematic diagram of enhancing transmission and enhancing reflection of the second filter layer according to an embodiment of the present invention;

[0050] Figure 7 It is a three-dimensional schematic diagram of the second filter layer enhancing transmission and enhancing reflection according to an embodiment of the present invention;

[0051] Figure 8 is a flow chart of a method for manufacturing an image sensor according to an embodiment of the present invention.

[0052] Among them, Figures 1 to 8 The reference numerals are described as follows:

[0053] 10-substrate; 11-first filter layer; 111-first light-transmitting material layer; 112-second light-transmitting material layer; 12-second filter layer; 121-third light-transmitting material layer; 122-fourth light-transmitting material layer; 123-fifth light-transmitting material layer; 13-second metal grid; 14-first metal grid. DETAILED DESCRIPTION

[0054] In order to make the purpose, advantages and features of the present invention more clear, the image sensor and the manufacturing method thereof proposed by the present invention are further described in detail below in conjunction with the accompanying drawings. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0055] An embodiment of the present invention provides an image sensor, comprising: a substrate; a filter layer formed on the substrate, the filter layer comprising a first filter layer and a second filter layer, the first filter layer comprising a first light-transmitting material layer and a second light-transmitting material layer, the first light-transmitting material layer being closer to the substrate than the second light-transmitting material layer, the refractive index of the second light-transmitting material layer being greater than the refractive index of the first light-transmitting material layer, the first filter layer comprising a first region, a second region, a third region, and a fourth region, the first region, the second region, the third region, and the fourth region being adjacent to each other in sequence, the first filter layer located in the first region, the second region, the third region, and the fourth region having different optical thicknesses, the first region allowing other color light rays except the first color light rays in the mixed color light rays to pass through, the second region or the fourth region allowing other color light rays except the second color light rays in the mixed color light rays to pass through, and the third region allowing other color light rays except the third color light in the mixed color light rays to pass through; the second filter layer is located above the first region, the second region, the third region, and the fourth region.

[0056] See below Figure 1 to Figure 7 The image sensor provided by this embodiment is described in more detail. In order to facilitate the description of the distribution of the second filter layer, Figure 2 A1, A2, A3 and A4 represent the second filter layer above the first filter layer in the first area, the second area, the third area and the fourth area respectively.

[0057] The substrate 10 may be a wafer or a chip, and device structures such as MOS transistors, resistors, and capacitors may be formed in the substrate 10 .

[0058] The material or device function of the substrate 10 is not limited here.

[0059] The filter layer is formed on the substrate 10, and the filter layer includes a first filter layer 11 and a second filter layer 12. The first filter layer 11 includes a first light-transmitting material layer 111 and a second light-transmitting material layer 112. The first light-transmitting material layer 111 is closer to the substrate 10 than the second light-transmitting material layer 112. The refractive index of the second light-transmitting material layer 112 is greater than the refractive index of the first light-transmitting material layer 111. The first filter layer 11 includes a first area A1, a second area A2, a third area A3, and a fourth area A4. The first area A1, the second area A2, the third area A3, and the fourth area A4 are arranged in order of Two adjacent first filter layers 11 located in the first area A1, the second area A2, the third area A3, and the fourth area A4 have different optical thicknesses. The first area A1 allows other color light except the first color light in the mixed color light to pass through, the second area A2 or the fourth area A4 allows other color light except the second color light in the mixed color light to pass through, and the third area A3 allows other color light except the third color light in the mixed color light to pass through; the second filter layer 12 is located above the first area A1, the second area A2, the third area A3, and the fourth area A4.

[0060] The optical thickness is the product of the physical thickness and the refractive index. The mixed color light includes at least three color lights. In one embodiment, the mixed color light is, for example, white light.

[0061] The image sensor also includes a pixel array, which is arranged in the substrate 10. Pixels in the pixel array are correspondingly formed below the first area A1, the second area A2, the third area A3, and the fourth area A4, and adjacent pixels are isolated by an isolation structure (not shown).

[0062] The pixel includes a photosensitive device (eg, a photodiode) for converting absorbed photons into electrical signals.

[0063] The isolation structure may be a deep trench isolation structure extending from the surface of the substrate 10 into the substrate 10 ; the material of the isolation structure may be at least one of insulating materials such as silicon oxide, silicon oxynitride and silicon nitride.

[0064] By adjusting the optical thickness of the first filter layer 11 of the first area A1, the first area A1 can allow other color lights except the first color light in the mixed color light to pass through, so that the pixels below the first area A1 can output the complementary color of the first color light through algorithm calculation; by adjusting the optical thickness of the first filter layer 11 of the second area A2 or the fourth area A4, the second area A2 or the fourth area A4 can allow other color lights except the second color light in the mixed color light to pass through, so that the pixels below the second area A2 or the fourth area A4 can output the complementary color of the second color light through algorithm calculation; by adjusting the optical thickness of the first filter layer 11 of the third area A3, the third area A3 can allow other color lights except the third color light in the mixed color light to pass through, so that the pixels below the third area A3 can output the complementary color of the third color light through algorithm calculation.

[0065] In one embodiment, adjusting the optical thickness of the first filter layer 11 of the first area A1, the second area A2, the third area A3, and the fourth area A4 includes adjusting the optical thickness of the second light-transmitting material layer 112 of the first area A1, the second area A2, the third area A3, and the fourth area A4, so that the first filter layer 11 of the first area A1 enhances the reflection of the first color light in a direction away from the substrate 10, the first filter layer 11 of the second area A2 or the fourth area A4 enhances the reflection of the second color light in a direction away from the substrate 10, and the first filter layer 11 of the third area A3 enhances the reflection of the third color light in a direction away from the substrate 10, so that the first filter layer 11 of the first area A1 prevents the first color light in the mixed color light from passing through, the first filter layer 11 of the second area A2 or the fourth area A4 prevents the second color light in the mixed color light from passing through, and the first filter layer 11 of the third area A3 prevents the third color light in the mixed color light from passing through.

[0066] In one embodiment, the first color light is red light, that is, when the mixed color light is incident on the first filter layer 11 of the first area A1, the red light is reflected by the first filter layer 11 (that is, the first filter layer 11 prevents the red light from passing through), and the other color lights except the red light in the mixed color light pass through the first filter layer 11 of the first area A1 and enter the pixel, so that the pixel below the first area A1 outputs the complementary color of red (that is, cyan) through the algorithm calculation data; the second color light is green light, that is, when the mixed color light is incident on the first filter layer 11 of the second area A2 or the fourth area A4, the green light is reflected by the first filter layer 11 (that is, the first filter layer 11 prevents the green light from passing through), and the mixed color light Light rays of other colors except the green light pass through the first filter layer 11 of the second area A2 or the fourth area A4 and enter the pixel, so that the pixel below the second area A2 or the fourth area A4 outputs the complementary color of green (i.e., magenta) through the algorithm calculation data; the third color light is blue light, that is, when the mixed color light is incident on the first filter layer 11 of the third area A3, the blue light is reflected by the first filter layer 11 (i.e., the first filter layer 11 prevents the blue light from passing through), and light rays of other colors except the blue light in the mixed color light pass through the first filter layer 11 of the third area A3 and enter the pixel, so that the pixel below the third area A3 outputs the complementary color of blue (i.e., yellow) through the algorithm calculation data.

[0067] In one embodiment, taking the first color light as red light, the second color light as green light, and the third color light as blue light as an example, for the traditional Bayer model Pattern), the red filter layer, the green filter layer and the blue filter layer only transmit red light, green light and blue light respectively, so that the pixels below the filter layer display red, green and blue, and then the color restoration is realized by combining the data of adjacent pixels through algorithm calculation, for example, the pixel below the green filter layer is color-fitted by the algorithm according to the data of the pixels below the adjacent red filter layer and the blue filter layer; in the present invention, the first filter layer 11 of the first area A1 transmits the superposition of green light and blue light, the first filter layer 11 of the second area A2 or the fourth area A4 transmits the superposition of red light and blue light, and the first filter layer 11 of the third area A3 transmits the superposition of green light and red light, that is, the light transmitted by the first filter layer 11 above each pixel is only the superposition of two colors, then, the color restoration can also be realized by combining the data of adjacent pixels through the algorithm, for example, the pixel below the second area A2 or the fourth area A4 can also be color-fitted by the algorithm according to the data of the pixels below the adjacent first area A1 and the pixels below the third area A3, and then the complementary color of green (i.e. magenta) is output.

[0068] The second light filter layer 12 is formed on the first light filter layer 11, and the second light filter layer 12 includes a fourth light-transmitting material layer 122 and a fifth light-transmitting material layer 123. The fourth light-transmitting material layer 122 is closer to the substrate 10 than the fifth light-transmitting material layer 123, and the refractive index of the fourth light-transmitting material layer 122 is greater than the refractive index of the fifth light-transmitting material layer 123; a third light-transmitting material layer 121 is formed between the fourth light-transmitting material layer 122 and the second light-transmitting material layer 112, and the refractive index of the third light-transmitting material layer 121 is less than the refractive index of the second light-transmitting material layer 112 and the fourth light-transmitting material layer 122.

[0069] By adjusting the optical thickness of the second filter layer 12 above the first area A1, the first color light that has not entered the first area A1 enters at least one of the second area A2, the third area A3, and the fourth area A4; by adjusting the optical thickness of the second filter layer 12 above the second area A2 or the fourth area A4, the second color light that has not entered the second area A2 or the fourth area A4 enters at least one of the first area A1 and the third area A3; by adjusting the optical thickness of the second filter layer 12 above the third area A3, the third color light that has not entered the third area A3 enters at least one of the first area A1, the second area A2, and the fourth area A4.

[0070] In one embodiment, adjusting the optical thickness of the second filter layer 12 above the first area A1, the second area A2, the third area A3, and the fourth area A4 includes adjusting the optical thickness of the fourth light-transmitting material layer 122 and the fifth light-transmitting material layer 123 above the first area A1, the second area A2, the third area A3, and the fourth area A4, so that the second filter layer 12 above the first area A1 enhances the transmission of the first color light and enhances the reflection of the first color light toward the direction close to the substrate 10, and the second filter layer 12 above the second area A2 or the fourth area A4 enhances the transmission of the first color light toward the direction close to the substrate 10. The second filter layer 12 above the third area A3 enhances the transmission of the third color light and enhances the reflection of the third color light toward the substrate 10, so that the first color light that has not entered the first area A1 enters at least one of the second area A2, the third area A3, and the fourth area A4, the second color light that has not entered the second area A2 or the fourth area A4 enters at least one of the first area A1 and the third area A3, and the third color light that has not entered the third area A3 enters at least one of the first area A1, the second area A2, and the fourth area A4.

[0071] The principle of the second filter layer 12 enhancing the transmission of a certain color of light includes: Figure 6As shown, when incident light L1 of a certain wavelength (i.e., a certain color) is incident from the air to the upper surface B3 of the fifth light-transmitting material layer 123, reflection and refraction will occur on the upper surface B3 of the fifth light-transmitting material layer 123 to obtain reflected light L2 and refracted light respectively. The reflected light L2 returns to the air in a direction away from the substrate 10, and the refracted light will also be reflected on the lower surface B4 of the fifth light-transmitting material layer 123, and after refraction by the upper surface B3 of the fifth light-transmitting material layer 123, refracted light L3 is obtained. The refracted light L3 also returns to the air in a direction away from the substrate 10. Then, the incident light L1 will return to the air after being reflected twice by the upper surface B3 and the lower surface B4 of the fifth light-transmitting material layer 123; because when the light is emitted from the optically sparse medium to the optically dense medium (the refractive index of the optically sparse medium is smaller than the refractive index of the optically dense medium), the reflected light has a half-wave loss, and the refractive index of the air is smaller than the refractive index of the fifth light-transmitting material layer 123, and the refractive index of the fifth light-transmitting material layer 123 is smaller than the refractive index of the fourth light-transmitting material layer 122, therefore, the two reflections of the light on the upper surface B3 and the lower surface B4 of the fifth light-transmitting material layer 123 have a half-wave loss, so that the optical path difference of the twice reflected light is d1=2*n4*h1 (where n4 is the refractive index of the fifth light-transmitting material layer 123, and h1 is the physical thickness of the fifth light-transmitting material layer 123). Furthermore, when the optical path difference of the light reflected twice by the fifth light-transmitting material layer 123 in the direction away from the substrate 10 is equal to an odd multiple of half the wavelength, the light returned to the air after the two reflections will destructively interfere, thereby reducing the energy of the light reflected by the fifth light-transmitting material layer 123 as a whole to the air. Then, according to the law of conservation of energy, the energy of the transmitted light passing through the fifth light-transmitting material layer 123 will increase, that is, enhanced transmission of the incident light L1 in the direction close to the substrate 10 is achieved. Among them, the transmitted light passing through the fifth light-transmitting material layer 123 can be refracted twice by the lower surface B4 of the fifth light-transmitting material layer 123 and the lower surface B5 of the fourth light-transmitting material layer 122 to obtain the transmitted light L4, and the transmitted light L4 is incident on the first filter layer 11 after passing through the third light-transmitting material layer 121.

[0072] Among them, the optical path difference of the light reflected twice by the fifth light-transmitting material layer 123 in the direction away from the substrate 10 is equal to an odd multiple of half the wavelength, that is, 2*n4*h1=(2k-1)*λ' / 2. When k=1, the physical thickness of the fifth light-transmitting material layer 123 is the thinnest, so that 2*n4*h1=λ' / 2. Then, the physical thickness of the fifth light-transmitting material layer 123 can be calculated to be h1=λ' / (4*n4), where λ' is the wavelength of light enhanced by the second filter layer 12 in the direction close to the substrate 10.

[0073] Therefore, when the refractive index of the fifth light-transmitting material layer 123 is smaller than the refractive index of the fourth light-transmitting material layer 122, by adjusting the optical thickness of the fifth light-transmitting material layer 123 above each area (i.e., the first area A1, the second area A2, the third area A3, and the fourth area A4), the second filter layer 12 above each area can enhance the transmission of light of a specific wavelength (i.e., a certain color) toward the direction close to the substrate 10, thereby increasing the transmittance of light of a specific wavelength toward the direction close to the substrate 10.

[0074] The physical thicknesses of the fifth light-transmitting material layer 123 above the first area A1, the second area A2 (or the fourth area A4) and the third area A3 are λ1 / (4*n4), λ2 / (4*n4) and λ3 / (4*n4), respectively; λ1, λ2 and λ3 are the wavelengths of the first color light, the second color light and the third color light, respectively.

[0075] When the first color light is red light, the second color light is green light, and the third color light is blue light, due to λ1>λ2>λ3, the physical thickness of the fifth light-transmitting material layer 123 from the first area A1, the second area A2 (or the fourth area A4) to the third area A3 is reduced in sequence, such as Figure 3 and Figure 4 shown.

[0076] The principle of the first filter layer 11 enhancing the reflection of a certain color of light includes: Figure 5As shown, when the transmitted light L4 of a certain wavelength (i.e., a certain color) is incident from the third light-transmitting material layer 121 to the upper surface B1 of the second light-transmitting material layer 112, reflection and refraction will occur on the upper surface B1 of the second light-transmitting material layer 112 to obtain reflected light L5 and refracted light respectively. The reflected light L5 returns to the third light-transmitting material layer 121 in a direction away from the substrate 10, and the refracted light will also be reflected on the lower surface B2 of the second light-transmitting material layer 112, and after refraction on the upper surface B1 of the second light-transmitting material layer 112, refracted light L6 is obtained. The refracted light L6 also returns to the third light-transmitting material layer 121 in a direction away from the substrate 10. Then, the transmitted light L4 will return to the third light-transmitting material layer 121 after being reflected twice by the upper surface B1 and the lower surface B2 of the second light-transmitting material layer 112. Since the reflected light has a half-wave loss when the light is emitted from the optically sparse medium to the optically dense medium, and the refractive index of the third light-transmitting material layer 121 is smaller than the refractive index of the second light-transmitting material layer 112, and the refractive index of the second light-transmitting material layer 112 is larger than the refractive index of the first light-transmitting material layer 111, the light is only reflected on the upper surface B1 of the second light-transmitting material layer 112. There is a half-wave loss in the reflection of the light at the lower surface B2 of the second light-transmitting material layer 112, and there is no half-wave loss in the reflection of the light, so that the optical path difference of the light reflected twice at the upper surface B1 and the lower surface B2 of the second light-transmitting material layer 112 is d2=2*n1*h2+λ” / 2 (wherein, n1 is the refractive index of the second light-transmitting material layer 112, h2 is the physical thickness of the second light-transmitting material layer 112, and λ” is the wavelength of the light reflected twice by the first filter layer 11 in the direction away from the substrate 10). Moreover, when the optical path difference of the light reflected twice by the first filter layer 11 in the direction away from the substrate 10 is equal to an integer multiple of the wavelength, the interference of the light returned to the third light-transmitting material layer 121 after the two reflections will be strengthened, thereby increasing the energy of the light reflected by the first filter layer 11 as a whole into the third light-transmitting material layer 121, that is, achieving enhanced reflection of a certain color of light in the direction away from the substrate 10.

[0077] Among them, the optical path difference of the light reflected twice by the first filter layer 11 in the direction away from the substrate 10 is equal to an integer multiple of the wavelength, that is, 2*n1*h2+λ” / 2=k*λ”, when k=1, the physical thickness of the second light-transmitting material layer 112 is the thinnest, so that 2*n1*h2=λ” / 2, then, the physical thickness of the second light-transmitting material layer 112 can be calculated to be h2=λ” / (4*n1).

[0078] Therefore, when the refractive index of the third light-transmitting material layer 121 is smaller than the refractive index of the second light-transmitting material layer 112, and the refractive index of the second light-transmitting material layer 112 is greater than the refractive index of the first light-transmitting material layer 111, by adjusting the optical thickness of the second light-transmitting material layer 112 in each area (i.e., the first area A1, the second area A2, the third area A3, and the fourth area A4), the first filter layer 11 in each area can enhance the reflection of light of a specific wavelength (i.e., a certain color) in a direction away from the substrate 10 (i.e., toward the third light-transmitting material layer 121), thereby improving the reflectivity of light of a specific wavelength, and light of other wavelengths in the mixed color light are all transmitted, so that the pixels under each area output the complementary color of the light of the specific wavelength.

[0079] The physical thicknesses of the second light-transmitting material layer 112 in the first area A1, the second area A2 (or the fourth area A4) and the third area A3 are λ1 / (4*n1), λ2 / (4*n1) and λ3 / (4*n1), respectively; λ1, λ2 and λ3 are the wavelengths of the first color light, the second color light and the third color light, respectively, and n1 is the refractive index of the second light-transmitting material layer 112.

[0080] When the first color light is red light, the second color light is green light, and the third color light is blue light, due to λ1>λ2>λ3, the physical thickness of the second light-transmitting material layer 112 in the first area A1, the second area A2 (or the fourth area A4) to the third area A3 decreases in sequence, such as Figure 3 and Figure 4 shown.

[0081] The principle of the second filter layer 12 enhancing the reflection of a certain color of light includes: Figure 6As shown, when the enhanced reflected light L7 of a certain wavelength is incident from the second light-transmitting material layer 112 in the first filter layer 11 through the third light-transmitting material layer 121 to the lower surface B5 of the fourth light-transmitting material layer 122, reflection and refraction will occur on the lower surface B5 of the fourth light-transmitting material layer 122 to obtain reflected light L8 and refracted light respectively. The reflected light L8 returns to the third light-transmitting material layer 121 in a direction close to the substrate 10, and the refracted light will also be reflected on the upper surface B4 of the fourth light-transmitting material layer 122 (that is, the lower surface B4 of the fifth light-transmitting material layer 123), and after refraction at the lower surface B5 of the fourth light-transmitting material layer 122, refracted light L9 is obtained. The refracted light L9 also returns to the third light-transmitting material layer 121 in a direction close to the substrate 10. Then, the enhanced reflected light L7 will return to the third light-transmitting material layer 121 after being reflected twice by the lower surface B5 and the upper surface B4 of the fourth light-transmitting material layer 122; because when light is emitted from the optically sparse medium to the optically dense medium, the reflected light has a half-wave loss, and the refractive index of the third light-transmitting material layer 121 is less than the refractive index of the fourth light-transmitting material layer 122, and the refractive index of the fourth light-transmitting material layer 122 is greater than the refractive index of the fifth light-transmitting material layer 123, therefore, only the reflection of the light on the lower surface B5 of the fourth light-transmitting material layer 122 has a half-wave loss, The upper surface B4 of the fourth light-transmitting material layer 122 reflects light without half-wave loss, so that the optical path difference of the light reflected twice on the lower surface B5 and the upper surface B4 of the fourth light-transmitting material layer 122 is d3=2*n2*n3*h3+λ”' / 2 (wherein, n2 is the refractive index of the third light-transmitting material layer 121, n3 is the refractive index of the fourth light-transmitting material layer 122, h3 is the physical thickness of the fourth light-transmitting material layer 122, and λ”' is the wavelength of the light reflected twice by the second filter layer 12 in the direction close to the substrate 10). Moreover, when the optical path difference of the light reflected twice by the second filter layer 12 in the direction close to the substrate 10 is equal to an integer multiple of the wavelength, the interference of the light returning to the third light-transmitting material layer 121 after the two reflections will be enhanced, thereby increasing the energy of the light reflected by the fourth light-transmitting material layer 122 as a whole into the third light-transmitting material layer 121, that is, the enhanced reflection of a certain color of light by the second filter layer 12 in the direction close to the substrate 10 is achieved.

[0082] Among them, the optical path difference of the light reflected twice by the second filter layer 12 in the direction close to the substrate 10 is equal to an integer multiple of the wavelength, that is, 2*n2*n3*h3+λ"' / 2=k*λ"'. When k=1, the physical thickness of the fourth light-transmitting material layer 122 is the thinnest, so that 2*n2*n3*h3=λ"' / 2. Then, the physical thickness of the fourth light-transmitting material layer 122 can be calculated as h3=λ"' / (4*n2*n3).

[0083] Therefore, when the refractive index of the third light-transmitting material layer 121 is smaller than the refractive index of the fourth light-transmitting material layer 122, and the refractive index of the fourth light-transmitting material layer 122 is greater than the refractive index of the fifth light-transmitting material layer 123, by adjusting the optical thickness of the fourth light-transmitting material layer 122 above each region (i.e., the first region A1, the second region A2, the third region A3, and the fourth region A4), the second filter layer 12 in each region can enhance the reflection of light of a specific wavelength (i.e., a certain color) toward the direction close to the substrate 10, thereby improving the reflectivity of light of a specific wavelength.

[0084] The physical thicknesses of the fourth light-transmitting material layer 122 over the first area A1, the second area A2 (or the fourth area A4) and the third area A3 are λ1 / (4*n2*n3), λ2 / (4*n2*n3) and λ3 / (4*n2*n3), respectively.

[0085] When the first color light is red light, the second color light is green light, and the third color light is blue light, due to λ1>λ2>λ3, the physical thickness of the fourth light-transmitting material layer 122 from the first area A1, the second area A2 (or the fourth area A4) to the third area A3 is reduced in sequence, such as Figure 3 and Figure 4 shown.

[0086] The physical thicknesses of the first light-transmitting material layer 111 in the first area A1 , the second area A2 (or the fourth area A4 ), and the third area A3 may be the same or different.

[0087] Preferably, top surfaces of the third light-transmitting material layer 121 above the first area A1 , the second area A2 , the third area A3 , and the fourth area A4 are flush.

[0088] In one embodiment, the material of the first light-transmitting material layer 111 includes silicon oxide, and the material of the second light-transmitting material layer 112 includes silicon nitride.

[0089] Preferably, the first filter layer 11 includes the first light-transmitting material layer 111 and the second light-transmitting material layer 112 which are periodically and alternately stacked, the first light-transmitting material layer 111 in each period is closer to the substrate 10 than the second light-transmitting material layer 112, and the number of periods of the periodic alternating stacking is greater than or equal to 3, so that the transmission amounts of the first color light, the second color light and the third color light in the first area A1, the second area A2 (or the fourth area A4) and the third area A3 of the first filter layer 11 in the direction close to the substrate 10 can be reduced as much as possible, thereby enabling the first filter layer 11 in the first area A1, the second area A2 (or the fourth area A4) and the third area A3 to respectively enhance the reflection of the first color light, the second color light and the third color light in the direction away from the substrate 10.

[0090] Preferably, the second filter layer 12 includes the fourth light-transmitting material layer 122 and the fifth light-transmitting material layer 123 that are periodically and alternately stacked, the fourth light-transmitting material layer 122 in each period is closer to the substrate 10 than the fifth light-transmitting material layer 123, and the number of periods of the periodic alternating stacking is greater than or equal to 3, so that the transmission amounts of the first color light, the second color light and the third color light in the direction away from the substrate 10 of the second filter layer 12 above the first area A1, the second area A2 (or the fourth area A4) and the third area A3, respectively, can be reduced as much as possible, thereby enabling the second filter layer 12 above the first area A1, the second area A2 (or the fourth area A4) and the third area A3 to achieve enhanced reflection of the first color light, the second color light and the third color light in the direction close to the substrate 10, respectively.

[0091] In addition, if Figure 6As shown, when light is emitted from an optically sparse medium to an optically dense medium, the reflected light has a half-wave loss, and the refractive index of the third light-transmitting material layer 121 is smaller than the refractive index of the fourth light-transmitting material layer 122, and the refractive index of the fourth light-transmitting material layer 122 is greater than the refractive index of the fifth light-transmitting material layer 123. Therefore, for the light incident from the fifth light-transmitting material layer 123 to the fourth light-transmitting material layer 122, only the reflection of the light on the upper surface B4 of the fourth light-transmitting material layer 122 has a half-wave loss, and the reflection of the light on the lower surface B5 of the fourth light-transmitting material layer 122 has no half-wave loss, so that the optical path difference d4 of the light reflected twice by the upper surface B4 and the lower surface B5 of the fourth light-transmitting material layer 122 is 2*n3*n4*h4+λ”” / 2 (wherein h4 is the physical thickness of the fourth light-transmitting material layer 122, and λ”” is the wavelength of the light reflected twice by the fourth light-transmitting material layer 122 in the direction away from the substrate 10).

[0092] Moreover, the optical path difference of the light reflected twice by the fourth light-transmitting material layer 122 in the direction away from the substrate 10 is equal to an integer multiple of the wavelength, that is, 2*n3*n4*h4+λ”” / 2=k*λ””. When k=1, the physical thickness of the fourth light-transmitting material layer 122 is the thinnest, so that 2*n3*n4*h4=λ”” / 2. Then, the physical thickness of the fourth light-transmitting material layer 122 can be calculated to be h4=λ”” / (4*n3*n4).

[0093] Then, by adjusting the physical thickness h4 of the fourth light-transmitting material layer 122 to satisfy the above formula, the second light filter layer 12 can enhance the reflection of light of a specific wavelength in a direction away from the substrate 10. However, the transmittance of light of a specific wavelength in a direction close to the substrate 10 will be reduced. Therefore, in order to prevent the second light filter layer 12 from enhancing the reflection of light of a specific wavelength in a direction away from the substrate 10, the physical thickness of the fourth light-transmitting material layer 122 should be less than λ"" / (4*n3*n4).

[0094] Preferably, the physical thickness of the fourth light-transmitting material layer 122 above the first area A1, the second area A2, the third area A3 and the fourth area A4 is less than λ4 / (4*n3*n4); λ4 is the wavelength of the light with the smallest wavelength in the mixed color light, and λ"" is greater than or equal to λ4. If the second filter layer 12 can avoid enhancing the reflection of the light with the smallest wavelength in the mixed color light in a direction away from the substrate 10, then the second filter layer 12 can avoid enhancing the reflection of all wavelengths in the mixed color light in a direction away from the substrate 10. In one embodiment, λ4=360nm.

[0095] Since when the second filter layer 12 enhances the reflection of light of a specific wavelength toward the direction close to the substrate 10, the physical thickness h3 of the fourth light-transmitting material layer 122 is h3=λ”' / (4*n2*n3), and the physical thickness of the fourth light-transmitting material layer 122 is less than λ4 / (4*n3*n4), then it can be calculated that n2 / n4>λ”' / λ4. Among them, since λ”' is greater than or equal to λ4, n2>n4, that is, the refractive index of the third light-transmitting material layer 121 is greater than the refractive index of the fifth light-transmitting material layer 123.

[0096] In the above embodiment, in the first area A1, λ', λ", λ"' and λ"" are all wavelengths of the first color light; in the second area A2 or the fourth area A4, λ', λ", λ"' and λ"" are all wavelengths of the second color light; in the third area A3, λ', λ", λ"' and λ"" are all wavelengths of the third color light.

[0097] It should be noted that the wavelengths in the above embodiments all refer to the wavelengths of light in a vacuum.

[0098] The image sensor further includes: a first metal grid 14 formed in the first filter layer 11 and the second filter layer 12, the first metal grid 14 is used to isolate adjacent filter layer sublayers from each other, the filter layer sublayer includes the first filter layer 11 in the first area A1, the second area A2, the third area A3 and the fourth area A4, and the second filter layer 12 correspondingly located above the first filter layer 11 in the first area A1, the second area A2, the third area A3 and the fourth area A4. The first metal grid 14 is located on the isolation structure to avoid optical crosstalk between adjacent pixels. The filter layer sublayer may also include a third light-transmitting material layer 121 between the first filter layer 11 and the second filter layer 12 correspondingly located in the first area A1, the second area A2, the third area A3 and the fourth area A4.

[0099] In one embodiment, the image sensor may further include: a second metal grid 13 formed in the first filter layer 11, and the second metal grid 13 is used to isolate the first area A1, the second area A2, the third area A3, and the fourth area A4 from each other, that is, the second metal grid 13 is located between the first filter layer 11 in adjacent areas of the first area A1, the second area A2, the third area A3, and the fourth area A4.

[0100] In other embodiments, only the first metal grid 14 may be included without including the second metal grid 13 .

[0101] like Figure 7 As shown, when the incident light L1 of a certain wavelength is incident on the upper surface of the second filter layer 12 above one of the first area A1, the second area A2, the third area A3 and the fourth area A4, taking the incident light L1 on the upper surface of the second filter layer 12 above the first area A1 as an example, the second filter layer 12 enhances the transmission of the first color light in the direction close to the substrate 10, so that the first color light fully enters the upper surface of the first filter layer 11 in the first area A1, and the first filter layer 11 in the first area A1 is incident on the upper surface of the second filter layer 12 in the direction away from the substrate 10. The first color light is enhanced and reflected, so that the first color light fully enters the lower surface of the second filter layer 12 above the first area A1, and the second filter layer 12 enhances the reflection of the first color light in the direction close to the substrate 10, so that the first color light is repeatedly enhanced and reflected between the first filter layer 11 and the second filter layer 12; because the second metal grid 13 does not enter the second filter layer 12, the first color light that finally does not enter the first area A1 will have a probability of entering the second area A2, the third area A3, and the fourth area A4 (such as Figure 7 L10 in the first region A1, the first color filter layer 11 in the second region A2, the third region A3 and the fourth region A4 can transmit the first color light, so that in a sufficiently long time (for example, the time of a single exposure), the first color light will enter the pixel below at least one of the second region A2, the third region A3 and the fourth region A4 after a sufficiently long time of enhanced reflection, so that the first color light entering the second filter layer 12 above the single whole formed by the first region A1, the second region A2, the third region A3 and the fourth region A4 can be fully transmitted into the four pixels below the single whole formed by the first region A1, the second region A2, the third region A3 and the fourth region A4. In the first region A1, the light of other colors except the first color light in the mixed color light is directly transmitted downward into the pixel through the second filter layer 12 and the first filter layer 11.

[0102] As can be seen from the above, since the refractive index of the second light-transmitting material layer 112 in the first light-filtering layer 11 is greater than the refractive index of the first light-transmitting material layer 111 in the first light-filtering layer 11, the first light-filtering layer 11 located in the first area A1, the second area A2, the third area A3, and the fourth area A4 have different optical thicknesses, so that the first area A1 allows other color lights except the first color light in the mixed color light to pass through, the second area A2 or the fourth area A4 allows other color lights except the second color light in the mixed color light to pass through, and the third area A3 or the fourth area A4 allows other color lights except the second color light in the mixed color light to pass through. Area A3 allows light of other colors except the third color in the mixed color light to pass through, that is, light of one color in the mixed color light incident on the first filter layer 11 of each area is reflected, and light of other colors in the mixed color light incident on the first filter layer 11 of each area are transmitted into the pixel, and each pixel loses light of one color. Compared with the traditional Bayer model in which the first filter layer 11 in each area only transmits light of one color and absorbs light of other colors, the first filter layer 11 of the present invention improves the photon transmittance, reduces the loss of photons, and thereby improves the quantum efficiency.

[0103] Furthermore, in the present invention, since the second filter layer 12 is formed above the first area A1, the second area A2, the third area A3, and the fourth area A4, the second filter layer 12 above the first area A1 can allow the first color light that has not entered the first area A1 to enter at least one of the second area A2, the third area A3, and the fourth area A4, the second filter layer 12 above the second area A2 or the fourth area A4 can allow the second color light that has not entered the second area A2 or the fourth area A4 to enter at least one of the first area A1 and the third area A3, and the second filter layer 12 above the third area A3 can allow the second color light that has not entered the second area A2 or the fourth area A4 to enter at least one of the first area A1 and the third area A3. The third color light that has not entered the third area A3 can enter at least one of the first area A1, the second area A2, and the fourth area A4, that is, the light of the corresponding color lost by the first filter layer 11 in a certain area can enter other areas and be transmitted into the pixels below the other areas, thereby making the mixed color light of the second filter layer 12 incident on the single whole formed by the first area A1, the second area A2, the third area A3 and the fourth area A4 can all enter the four pixels below, that is, the mixed color light incident on the filter layer can be completely transmitted into the pixel, realizing full photon absorption without photon loss, and greatly improving the quantum efficiency.

[0104] In one embodiment, the exposure intensity of each color of the pixels under each area can be calculated, and the photosensitive device in the pixel under each area can also sense the component of the corresponding color, so that the color of the four pixels under the whole composed of the first area A1, the second area A2, the third area A3 and the fourth area A4 can be inferred. Since there is no photon loss for the four pixels under the whole composed of the first area A1, the second area A2, the third area A3 and the fourth area A4, all the photons entering the four pixels are converted into photoelectrons by the photosensitive device, so that there is no color loss for the four pixels under the whole composed of the first area A1, the second area A2, the third area A3 and the fourth area A4, and the four pixels under the whole composed of the first area A1, the second area A2, the third area A3 and the fourth area A4 obtain completely real colors, thereby realizing a full-color image sensor. In the existing method, color restoration is achieved through an algorithm based on the data of adjacent pixels, resulting in color loss, and the obtained color is not real.

[0105] In summary, the image sensor provided by the present invention comprises: a substrate; a filter layer formed on the substrate, the filter layer comprises a first filter layer and a second filter layer, the first filter layer comprises a first light-transmitting material layer and a second light-transmitting material layer, the first light-transmitting material layer is closer to the substrate than the second light-transmitting material layer, the refractive index of the second light-transmitting material layer is greater than the refractive index of the first light-transmitting material layer, the first filter layer comprises a first region, a second region, a third region, and a fourth region, the first region, the second region, the third region, and the fourth region are adjacent to each other in sequence, the first filter layer located in the first region, the second region, the third region, and the fourth region has different optical thicknesses, the first region allows other color lights other than the first color light in the mixed color light to pass through, the second region or the fourth region allows other color lights other than the second color light in the mixed color light to pass through, and the third region allows other color lights other than the third color light in the mixed color light to pass through; the second filter layer is located above the first region, the second region, the third region, and the fourth region. The image sensor of the present invention greatly improves the quantum efficiency.

[0106] An embodiment of the present invention provides a method for manufacturing an image sensor. Figure 8 , Figure 8 1 is a flow chart of a method for manufacturing an image sensor according to an embodiment of the present invention, wherein the method for manufacturing an image sensor comprises:

[0107] Step S1, providing a substrate;

[0108] Step S2, forming a filter layer on the substrate, the filter layer includes a first filter layer and a second filter layer, the first filter layer includes a first light-transmitting material layer and a second light-transmitting material layer, the first light-transmitting material layer is closer to the substrate than the second light-transmitting material layer, the refractive index of the second light-transmitting material layer is greater than the refractive index of the first light-transmitting material layer, the first filter layer includes a first region, a second region, a third region, and a fourth region, the first region, the second region, the third region, and the fourth region are adjacent to each other in sequence, the filter layers located in the first region, the second region, the third region, and the fourth region have different optical thicknesses, the first region allows other color light rays except the first color light ray in the mixed color light to pass through, the second region or the fourth region allows other color light rays except the second color light in the mixed color light to pass through, and the third region allows other color light rays except the third color light in the mixed color light to pass through; the second filter layer is located above the first region, the second region, the third region, and the fourth region.

[0109] See below Figure 1 to Figure 7 The manufacturing method of the image sensor provided by this embodiment is described in more detail. In order to facilitate the description of the distribution of the second filter layer, Figure 2 A1, A2, A3 and A4 represent the second filter layer above the first filter layer in the first area, the second area, the third area and the fourth area respectively.

[0110] According to step S1 , a substrate 10 is provided.

[0111] The substrate 10 may be a wafer or a chip, and device structures such as MOS transistors, resistors, and capacitors may be formed in the substrate 10 .

[0112] The material or device function of the substrate 10 is not limited here.

[0113] According to step S2, a filter layer is formed on the substrate 10, the filter layer includes a first filter layer 11 and a second filter layer 12, the first filter layer 11 includes a first light-transmitting material layer 111 and a second light-transmitting material layer 112, the first light-transmitting material layer 111 is closer to the substrate 10 than the second light-transmitting material layer 112, the refractive index of the second light-transmitting material layer 112 is greater than the refractive index of the first light-transmitting material layer 111, the first filter layer 11 includes a first area A1, a second area A2, a third area A3, and a fourth area A4, the first area A1, the second area A2, the third area A3, and the fourth area A4 The first filter layers 11 located in the first area A1, the second area A2, the third area A3, and the fourth area A4, which are adjacent to each other in sequence, have different optical thicknesses. The first area A1 allows light of other colors except the first color light in the mixed color light to pass through, the second area A2 or the fourth area A4 allows light of other colors except the second color light in the mixed color light to pass through, and the third area A3 allows light of other colors except the third color light in the mixed color light to pass through; the second filter layer 12 is located above the first area A1, the second area A2, the third area A3, and the fourth area A4.

[0114] The optical thickness is the product of the physical thickness and the refractive index. The mixed color light includes at least three color lights. In one embodiment, the mixed color light is, for example, white light.

[0115] Before forming the filter layer on the substrate, the manufacturing method of the image sensor also includes: forming a pixel array, the array is arranged in the substrate 10, and pixels in the pixel array are correspondingly formed below the first area A1, the second area A2, the third area A3, and the fourth area A4, and adjacent pixels are isolated by an isolation structure (not shown).

[0116] The pixel includes a photosensitive device (eg, a photodiode) for converting absorbed photons into electrical signals.

[0117] The isolation structure may be a deep trench isolation structure extending from the surface of the substrate 10 into the substrate 10 ; the material of the isolation structure may be at least one of insulating materials such as silicon oxide, silicon oxynitride and silicon nitride.

[0118] By adjusting the optical thickness of the first filter layer 11 of the first area A1, the first area A1 can allow other color lights except the first color light in the mixed color light to pass through, so that the pixels below the first area A1 can output the complementary color of the first color light through algorithm calculation; by adjusting the optical thickness of the first filter layer 11 of the second area A2 or the fourth area A4, the second area A2 or the fourth area A4 can allow other color lights except the second color light in the mixed color light to pass through, so that the pixels below the second area A2 or the fourth area A4 can output the complementary color of the second color light through algorithm calculation; by adjusting the optical thickness of the first filter layer 11 of the third area A3, the third area A3 can allow other color lights except the third color light in the mixed color light to pass through, so that the pixels below the third area A3 can output the complementary color of the third color light through algorithm calculation.

[0119] In one embodiment, adjusting the optical thickness of the first filter layer 11 of the first area A1, the second area A2, the third area A3, and the fourth area A4 includes adjusting the optical thickness of the second light-transmitting material layer 112 of the first area A1, the second area A2, the third area A3, and the fourth area A4, so that the first filter layer 11 of the first area A1 enhances the reflection of the first color light in a direction away from the substrate 10, the first filter layer 11 of the second area A2 or the fourth area A4 enhances the reflection of the second color light in a direction away from the substrate 10, and the first filter layer 11 of the third area A3 enhances the reflection of the third color light in a direction away from the substrate 10, so that the first filter layer 11 of the first area A1 prevents the first color light in the mixed color light from passing through, the first filter layer 11 of the second area A2 or the fourth area A4 prevents the second color light in the mixed color light from passing through, and the first filter layer 11 of the third area A3 prevents the third color light in the mixed color light from passing through.

[0120] In one embodiment, the first color light is red light, that is, when the mixed color light is incident on the first filter layer 11 of the first area A1, the red light is reflected by the first filter layer 11 (that is, the first filter layer 11 prevents the red light from passing through), and the other color lights except the red light in the mixed color light pass through the first filter layer 11 of the first area A1 and enter the pixel, so that the pixel below the first area A1 outputs the complementary color of red (that is, cyan) through the algorithm calculation data; the second color light is green light, that is, when the mixed color light is incident on the first filter layer 11 of the second area A2 or the fourth area A4, the green light is reflected by the first filter layer 11 (that is, the first filter layer 11 prevents the green light from passing through), and the mixed color light Light rays of other colors except the green light pass through the first filter layer 11 of the second area A2 or the fourth area A4 and enter the pixel, so that the pixel below the second area A2 or the fourth area A4 outputs the complementary color of green (i.e., magenta) through the algorithm calculation data; the third color light is blue light, that is, when the mixed color light is incident on the first filter layer 11 of the third area A3, the blue light is reflected by the first filter layer 11 (i.e., the first filter layer 11 prevents the blue light from passing through), and light rays of other colors except the blue light in the mixed color light pass through the first filter layer 11 of the third area A3 and enter the pixel, so that the pixel below the third area A3 outputs the complementary color of blue (i.e., yellow) through the algorithm calculation data.

[0121] In one embodiment, taking the first color light as red light, the second color light as green light, and the third color light as blue light as an example, for the traditional Bayer model Pattern), the red filter layer, the green filter layer and the blue filter layer only transmit red light, green light and blue light respectively, so that the pixels below the filter layer display red, green and blue, and then the color restoration is realized by combining the data of adjacent pixels through algorithm calculation, for example, the pixel below the green filter layer is color-fitted by the algorithm according to the data of the pixels below the adjacent red filter layer and the blue filter layer; in the present invention, the first filter layer 11 of the first area A1 transmits the superposition of green light and blue light, the first filter layer 11 of the second area A2 or the fourth area A4 transmits the superposition of red light and blue light, and the first filter layer 11 of the third area A3 transmits the superposition of green light and red light, that is, the light transmitted by the first filter layer 11 above each pixel is only the superposition of two colors, then, the color restoration can also be realized by combining the data of adjacent pixels through the algorithm, for example, the pixel below the second area A2 or the fourth area A4 can also be color-fitted by the algorithm according to the data of the pixels below the adjacent first area A1 and the pixels below the third area A3, and then the complementary color of green (i.e. magenta) is output.

[0122] The second light filter layer 12 is formed on the first light filter layer 11, and the second light filter layer 12 includes a fourth light-transmitting material layer 122 and a fifth light-transmitting material layer 123. The fourth light-transmitting material layer 122 is closer to the substrate 10 than the fifth light-transmitting material layer 123, and the refractive index of the fourth light-transmitting material layer 122 is greater than the refractive index of the fifth light-transmitting material layer 123; a third light-transmitting material layer 121 is formed between the fourth light-transmitting material layer 122 and the second light-transmitting material layer 112, and the refractive index of the third light-transmitting material layer 121 is less than the refractive index of the second light-transmitting material layer 112 and the fourth light-transmitting material layer 122.

[0123] By adjusting the optical thickness of the second filter layer 12 above the first area A1, the first color light that has not entered the first area A1 enters at least one of the second area A2, the third area A3, and the fourth area A4; by adjusting the optical thickness of the second filter layer 12 above the second area A2 or the fourth area A4, the second color light that has not entered the second area A2 or the fourth area A4 enters at least one of the first area A1 and the third area A3; by adjusting the optical thickness of the second filter layer 12 above the third area A3, the third color light that has not entered the third area A3 enters at least one of the first area A1, the second area A2, and the fourth area A4.

[0124] In one embodiment, adjusting the optical thickness of the second filter layer 12 above the first area A1, the second area A2, the third area A3, and the fourth area A4 includes adjusting the optical thickness of the fourth light-transmitting material layer 122 and the fifth light-transmitting material layer 123 above the first area A1, the second area A2, the third area A3, and the fourth area A4, so that the second filter layer 12 above the first area A1 enhances the transmission of the first color light and enhances the reflection of the first color light toward the direction close to the substrate 10, and the second filter layer 12 above the second area A2 or the fourth area A4 enhances the transmission of the first color light toward the direction close to the substrate 10. The second filter layer 12 above the third area A3 enhances the transmission of the third color light and enhances the reflection of the third color light toward the substrate 10, so that the first color light that has not entered the first area A1 enters at least one of the second area A2, the third area A3, and the fourth area A4, the second color light that has not entered the second area A2 or the fourth area A4 enters at least one of the first area A1 and the third area A3, and the third color light that has not entered the third area A3 enters at least one of the first area A1, the second area A2, and the fourth area A4.

[0125] The principle of the second filter layer 12 enhancing the transmission of a certain color of light includes: Figure 6As shown, when incident light L1 of a certain wavelength (i.e., a certain color) is incident from the air to the upper surface B3 of the fifth light-transmitting material layer 123, reflection and refraction will occur on the upper surface B3 of the fifth light-transmitting material layer 123 to obtain reflected light L2 and refracted light respectively. The reflected light L2 returns to the air in a direction away from the substrate 10, and the refracted light will also be reflected on the lower surface B4 of the fifth light-transmitting material layer 123, and after refraction by the upper surface B3 of the fifth light-transmitting material layer 123, refracted light L3 is obtained. The refracted light L3 also returns to the air in a direction away from the substrate 10. Then, the incident light L1 will return to the air after being reflected twice by the upper surface B3 and the lower surface B4 of the fifth light-transmitting material layer 123; because when the light is emitted from the optically sparse medium to the optically dense medium (the refractive index of the optically sparse medium is smaller than the refractive index of the optically dense medium), the reflected light has a half-wave loss, and the refractive index of the air is smaller than the refractive index of the fifth light-transmitting material layer 123, and the refractive index of the fifth light-transmitting material layer 123 is smaller than the refractive index of the fourth light-transmitting material layer 122, therefore, the two reflections of the light on the upper surface B3 and the lower surface B4 of the fifth light-transmitting material layer 123 have a half-wave loss, so that the optical path difference of the twice reflected light is d1=2*n4*h1 (where n4 is the refractive index of the fifth light-transmitting material layer 123, and h1 is the physical thickness of the fifth light-transmitting material layer 123). Furthermore, when the optical path difference of the light reflected twice by the fifth light-transmitting material layer 123 in the direction away from the substrate 10 is equal to an odd multiple of half the wavelength, the light returned to the air after the two reflections will destructively interfere, thereby reducing the energy of the light reflected by the fifth light-transmitting material layer 123 as a whole to the air. Then, according to the law of conservation of energy, the energy of the transmitted light passing through the fifth light-transmitting material layer 123 will increase, that is, enhanced transmission of the incident light L1 in the direction close to the substrate 10 is achieved. Among them, the transmitted light passing through the fifth light-transmitting material layer 123 can be refracted twice by the lower surface B4 of the fifth light-transmitting material layer 123 and the lower surface B5 of the fourth light-transmitting material layer 122 to obtain the transmitted light L4, and the transmitted light L4 is incident on the first filter layer 11 after passing through the third light-transmitting material layer 121.

[0126] Among them, the optical path difference of the light reflected twice by the fifth light-transmitting material layer 123 in the direction away from the substrate 10 is equal to an odd multiple of half the wavelength, that is, 2*n4*h1=(2k-1)*λ' / 2. When k=1, the physical thickness of the fifth light-transmitting material layer 123 is the thinnest, so that 2*n4*h1=λ' / 2. Then, the physical thickness of the fifth light-transmitting material layer 123 can be calculated to be h1=λ' / (4*n4), where λ' is the wavelength of light enhanced by the second filter layer 12 in the direction close to the substrate 10.

[0127] Therefore, when the refractive index of the fifth light-transmitting material layer 123 is smaller than the refractive index of the fourth light-transmitting material layer 122, by adjusting the optical thickness of the fifth light-transmitting material layer 123 above each area (i.e., the first area A1, the second area A2, the third area A3, and the fourth area A4), the second filter layer 12 above each area can enhance the transmission of light of a specific wavelength (i.e., a certain color) toward the direction close to the substrate 10, thereby increasing the transmittance of light of a specific wavelength toward the direction close to the substrate 10.

[0128] The physical thicknesses of the fifth light-transmitting material layer 123 above the first area A1, the second area A2 (or the fourth area A4) and the third area A3 are λ1 / (4*n4), λ2 / (4*n4) and λ3 / (4*n4), respectively; λ1, λ2 and λ3 are the wavelengths of the first color light, the second color light and the third color light, respectively.

[0129] When the first color light is red light, the second color light is green light, and the third color light is blue light, due to λ1>λ2>λ3, the physical thickness of the fifth light-transmitting material layer 123 from the first area A1, the second area A2 (or the fourth area A4) to the third area A3 is reduced in sequence, such as Figure 3 and Figure 4 shown.

[0130] The principle of the first filter layer 11 enhancing the reflection of a certain color of light includes: Figure 5As shown, when the transmitted light L4 of a certain wavelength (i.e., a certain color) is incident from the third light-transmitting material layer 121 to the upper surface B1 of the second light-transmitting material layer 112, reflection and refraction will occur on the upper surface B1 of the second light-transmitting material layer 112 to obtain reflected light L5 and refracted light respectively. The reflected light L5 returns to the third light-transmitting material layer 121 in a direction away from the substrate 10, and the refracted light will also be reflected on the lower surface B2 of the second light-transmitting material layer 112, and after refraction on the upper surface B1 of the second light-transmitting material layer 112, refracted light L6 is obtained. The refracted light L6 also returns to the third light-transmitting material layer 121 in a direction away from the substrate 10. Then, the transmitted light L4 will return to the third light-transmitting material layer 121 after being reflected twice by the upper surface B1 and the lower surface B2 of the second light-transmitting material layer 112. Since the reflected light has a half-wave loss when the light is emitted from the optically sparse medium to the optically dense medium, and the refractive index of the third light-transmitting material layer 121 is smaller than the refractive index of the second light-transmitting material layer 112, and the refractive index of the second light-transmitting material layer 112 is larger than the refractive index of the first light-transmitting material layer 111, the light is only reflected on the upper surface B1 of the second light-transmitting material layer 112. There is a half-wave loss in the reflection of the light at the lower surface B2 of the second light-transmitting material layer 112, and there is no half-wave loss in the reflection of the light, so that the optical path difference of the light reflected twice at the upper surface B1 and the lower surface B2 of the second light-transmitting material layer 112 is d2=2*n1*h2+λ” / 2 (wherein, n1 is the refractive index of the second light-transmitting material layer 112, h2 is the physical thickness of the second light-transmitting material layer 112, and λ” is the wavelength of the light reflected twice by the first filter layer 11 in the direction away from the substrate 10). Moreover, when the optical path difference of the light reflected twice by the first filter layer 11 in the direction away from the substrate 10 is equal to an integer multiple of the wavelength, the interference of the light returned to the third light-transmitting material layer 121 after the two reflections will be strengthened, thereby increasing the energy of the light reflected by the first filter layer 11 as a whole into the third light-transmitting material layer 121, that is, achieving enhanced reflection of a certain color of light in the direction away from the substrate 10.

[0131] Among them, the optical path difference of the light reflected twice by the first filter layer 11 in the direction away from the substrate 10 is equal to an integer multiple of the wavelength, that is, 2*n1*h2+λ” / 2=k*λ”, when k=1, the physical thickness of the second light-transmitting material layer 112 is the thinnest, so that 2*n1*h2=λ” / 2, then, the physical thickness of the second light-transmitting material layer 112 can be calculated to be h2=λ” / (4*n1).

[0132] Therefore, when the refractive index of the third light-transmitting material layer 121 is smaller than the refractive index of the second light-transmitting material layer 112, and the refractive index of the second light-transmitting material layer 112 is greater than the refractive index of the first light-transmitting material layer 111, by adjusting the optical thickness of the second light-transmitting material layer 112 in each area (i.e., the first area A1, the second area A2, the third area A3, and the fourth area A4), the first filter layer 11 in each area can enhance the reflection of light of a specific wavelength (i.e., a certain color) in a direction away from the substrate 10 (i.e., toward the third light-transmitting material layer 121), thereby improving the reflectivity of light of a specific wavelength, and light of other wavelengths in the mixed color light are all transmitted, so that the pixels under each area output the complementary color of the light of the specific wavelength.

[0133] The physical thicknesses of the second light-transmitting material layer 112 in the first area A1, the second area A2 (or the fourth area A4) and the third area A3 are λ1 / (4*n1), λ2 / (4*n1) and λ3 / (4*n1), respectively; λ1, λ2 and λ3 are the wavelengths of the first color light, the second color light and the third color light, respectively, and n1 is the refractive index of the second light-transmitting material layer 112.

[0134] When the first color light is red light, the second color light is green light, and the third color light is blue light, due to λ1>λ2>λ3, the physical thickness of the second light-transmitting material layer 112 in the first area A1, the second area A2 (or the fourth area A4) to the third area A3 decreases in sequence, such as Figure 3 and Figure 4 shown.

[0135] The principle of the second filter layer 12 enhancing the reflection of a certain color of light includes: Figure 6As shown, when the enhanced reflected light L7 of a certain wavelength is incident from the second light-transmitting material layer 112 in the first filter layer 11 through the third light-transmitting material layer 121 to the lower surface B5 of the fourth light-transmitting material layer 122, reflection and refraction will occur on the lower surface B5 of the fourth light-transmitting material layer 122 to obtain reflected light L8 and refracted light respectively. The reflected light L8 returns to the third light-transmitting material layer 121 in a direction close to the substrate 10, and the refracted light will also be reflected on the upper surface B4 of the fourth light-transmitting material layer 122 (that is, the lower surface B4 of the fifth light-transmitting material layer 123), and after refraction at the lower surface B5 of the fourth light-transmitting material layer 122, refracted light L9 is obtained. The refracted light L9 also returns to the third light-transmitting material layer 121 in a direction close to the substrate 10. Then, the enhanced reflected light L7 will return to the third light-transmitting material layer 121 after being reflected twice by the lower surface B5 and the upper surface B4 of the fourth light-transmitting material layer 122; because when light is emitted from the optically sparse medium to the optically dense medium, the reflected light has a half-wave loss, and the refractive index of the third light-transmitting material layer 121 is less than the refractive index of the fourth light-transmitting material layer 122, and the refractive index of the fourth light-transmitting material layer 122 is greater than the refractive index of the fifth light-transmitting material layer 123, therefore, only the reflection of the light on the lower surface B5 of the fourth light-transmitting material layer 122 has a half-wave loss, The upper surface B4 of the fourth light-transmitting material layer 122 reflects light without half-wave loss, so that the optical path difference of the light reflected twice on the lower surface B5 and the upper surface B4 of the fourth light-transmitting material layer 122 is d3=2*n2*n3*h3+λ”' / 2 (wherein, n2 is the refractive index of the third light-transmitting material layer 121, n3 is the refractive index of the fourth light-transmitting material layer 122, h3 is the physical thickness of the fourth light-transmitting material layer 122, and λ”' is the wavelength of the light reflected twice by the second filter layer 12 in the direction close to the substrate 10). Moreover, when the optical path difference of the light reflected twice by the second filter layer 12 in the direction close to the substrate 10 is equal to an integer multiple of the wavelength, the interference of the light returning to the third light-transmitting material layer 121 after the two reflections will be enhanced, thereby increasing the energy of the light reflected by the fourth light-transmitting material layer 122 as a whole into the third light-transmitting material layer 121, that is, the enhanced reflection of a certain color of light by the second filter layer 12 in the direction close to the substrate 10 is achieved.

[0136] Among them, the optical path difference of the light reflected twice by the second filter layer 12 in the direction close to the substrate 10 is equal to an integer multiple of the wavelength, that is, 2*n2*n3*h3+λ"' / 2=k*λ"'. When k=1, the physical thickness of the fourth light-transmitting material layer 122 is the thinnest, so that 2*n2*n3*h3=λ"' / 2. Then, the physical thickness of the fourth light-transmitting material layer 122 can be calculated as h3=λ"' / (4*n2*n3).

[0137] Therefore, when the refractive index of the third light-transmitting material layer 121 is smaller than the refractive index of the fourth light-transmitting material layer 122, and the refractive index of the fourth light-transmitting material layer 122 is greater than the refractive index of the fifth light-transmitting material layer 123, by adjusting the optical thickness of the fourth light-transmitting material layer 122 above each region (i.e., the first region A1, the second region A2, the third region A3, and the fourth region A4), the second filter layer 12 in each region can enhance the reflection of light of a specific wavelength (i.e., a certain color) toward the direction close to the substrate 10, thereby improving the reflectivity of light of a specific wavelength.

[0138] The physical thicknesses of the fourth light-transmitting material layer 122 over the first area A1, the second area A2 (or the fourth area A4) and the third area A3 are λ1 / (4*n2*n3), λ2 / (4*n2*n3) and λ3 / (4*n2*n3), respectively.

[0139] When the first color light is red light, the second color light is green light, and the third color light is blue light, due to λ1>λ2>λ3, the physical thickness of the fourth light-transmitting material layer 122 from the first area A1, the second area A2 (or the fourth area A4) to the third area A3 is reduced in sequence, such as Figure 3 and Figure 4 shown.

[0140] The physical thicknesses of the first light-transmitting material layer 111 in the first area A1 , the second area A2 (or the fourth area A4 ), and the third area A3 may be the same or different.

[0141] Preferably, top surfaces of the third light-transmitting material layer 121 above the first area A1, the second area A2 (or the fourth area A4) and the third area A3 are flush.

[0142] In one embodiment, the material of the first light-transmitting material layer 111 includes silicon oxide, and the material of the second light-transmitting material layer 112 includes silicon nitride.

[0143] Preferably, the first filter layer 11 includes the first light-transmitting material layer 111 and the second light-transmitting material layer 112 which are periodically and alternately stacked, the first light-transmitting material layer 111 in each period is closer to the substrate 10 than the second light-transmitting material layer 112, and the number of periods of the periodic alternating stacking is greater than or equal to 3, so that the transmission amounts of the first color light, the second color light and the third color light in the first area A1, the second area A2 (or the fourth area A4) and the third area A3 of the first filter layer 11 in the direction close to the substrate 10 can be reduced as much as possible, thereby enabling the first filter layer 11 in the first area A1, the second area A2 (or the fourth area A4) and the third area A3 to respectively enhance the reflection of the first color light, the second color light and the third color light in the direction away from the substrate 10.

[0144] Preferably, the second filter layer 12 includes the fourth light-transmitting material layer 122 and the fifth light-transmitting material layer 123 that are periodically and alternately stacked, the fourth light-transmitting material layer 122 in each period is closer to the substrate 10 than the fifth light-transmitting material layer 123, and the number of periods of the periodic alternating stacking is greater than or equal to 3, so that the transmission amounts of the first color light, the second color light and the third color light in the direction away from the substrate 10 of the second filter layer 12 above the first area A1, the second area A2 (or the fourth area A4) and the third area A3, respectively, can be reduced as much as possible, thereby enabling the second filter layer 12 above the first area A1, the second area A2 (or the fourth area A4) and the third area A3 to achieve enhanced reflection of the first color light, the second color light and the third color light in the direction close to the substrate 10, respectively.

[0145] In addition, if Figure 6As shown, when light is emitted from an optically sparse medium to an optically dense medium, the reflected light has a half-wave loss, and the refractive index of the third light-transmitting material layer 121 is smaller than the refractive index of the fourth light-transmitting material layer 122, and the refractive index of the fourth light-transmitting material layer 122 is greater than the refractive index of the fifth light-transmitting material layer 123. Therefore, for the light incident from the fifth light-transmitting material layer 123 to the fourth light-transmitting material layer 122, only the reflection of the light on the upper surface B4 of the fourth light-transmitting material layer 122 has a half-wave loss, and the reflection of the light on the lower surface B5 of the fourth light-transmitting material layer 122 has no half-wave loss, so that the optical path difference d4 of the light reflected twice by the upper surface B4 and the lower surface B5 of the fourth light-transmitting material layer 122 is 2*n3*n4*h4+λ”” / 2 (wherein h4 is the physical thickness of the fourth light-transmitting material layer 122, and λ”” is the wavelength of the light reflected twice by the fourth light-transmitting material layer 122 in the direction away from the substrate 10).

[0146] Moreover, the optical path difference of the light reflected twice by the fourth light-transmitting material layer 122 in the direction away from the substrate 10 is equal to an integer multiple of the wavelength, that is, 2*n3*n4*h4+λ”” / 2=k*λ””. When k=1, the physical thickness of the fourth light-transmitting material layer 122 is the thinnest, so that 2*n3*n4*h4=λ”” / 2. Then, the physical thickness of the fourth light-transmitting material layer 122 can be calculated to be h4=λ”” / (4*n3*n4).

[0147] Then, by adjusting the physical thickness h4 of the fourth light-transmitting material layer 122 to satisfy the above formula, the second light filter layer 12 can enhance the reflection of light of a specific wavelength in a direction away from the substrate 10. However, the transmittance of light of a specific wavelength in a direction close to the substrate 10 will be reduced. Therefore, in order to prevent the second light filter layer 12 from enhancing the reflection of light of a specific wavelength in a direction away from the substrate 10, the physical thickness of the fourth light-transmitting material layer 122 should be less than λ"" / (4*n3*n4).

[0148] Preferably, the physical thickness of the fourth light-transmitting material layer 122 above the first area A1, the second area A2, the third area A3 and the fourth area A4 is less than λ4 / (4*n3*n4); λ4 is the wavelength of the light with the smallest wavelength in the mixed color light, and λ"" is greater than or equal to λ4. If the second filter layer 12 can avoid enhancing the reflection of the light with the smallest wavelength in the mixed color light in a direction away from the substrate 10, then the second filter layer 12 can avoid enhancing the reflection of all wavelengths in the mixed color light in a direction away from the substrate 10. In one embodiment, λ4=360nm.

[0149] Since when the second filter layer 12 enhances the reflection of light of a specific wavelength toward the direction close to the substrate 10, the physical thickness h3 of the fourth light-transmitting material layer 122 is h3=λ”' / (4*n2*n3), and the physical thickness of the fourth light-transmitting material layer 122 is less than λ4 / (4*n3*n4), then it can be calculated that n2 / n4>λ”' / λ4. Among them, since λ”' is greater than or equal to λ4, n2>n4, that is, the refractive index of the third light-transmitting material layer 121 is greater than the refractive index of the fifth light-transmitting material layer 123.

[0150] In the above embodiment, in the first area A1, λ', λ", λ"' and λ"" are all wavelengths of the first color light; in the second area A2 or the fourth area A4, λ', λ", λ"' and λ"" are all wavelengths of the second color light; in the third area A3, λ', λ", λ"' and λ"" are all wavelengths of the third color light.

[0151] It should be noted that the wavelengths in the above embodiments all refer to the wavelengths of light in a vacuum.

[0152] The manufacturing method of the image sensor further includes: forming a first metal grid 14 in the first filter layer 11 and the second filter layer 12, wherein the first metal grid 14 is used to isolate adjacent filter layer sublayers from each other, wherein the filter layer sublayer includes the first filter layer 11 in the first area A1, the second area A2, the third area A3 and the fourth area A4, and the second filter layer 12 correspondingly located above the first filter layer 11 in the first area A1, the second area A2, the third area A3 and the fourth area A4. The first metal grid 14 is located on the isolation structure to avoid optical crosstalk between adjacent pixels. The filter layer sublayer may also include a third light-transmitting material layer 121 between the first filter layer 11 and the second filter layer 12 correspondingly located in the first area A1, the second area A2, the third area A3 and the fourth area A4.

[0153] In one embodiment, the method for manufacturing the image sensor may further include:

[0154] A second metal grid 13 is formed in the first filter layer 11, and the second metal grid 13 is used to isolate the first area A1, the second area A2, the third area A3, and the fourth area A4 from each other, that is, the second metal grid 13 is located between the first filter layer 11 in adjacent areas of the first area A1, the second area A2, the third area A3, and the fourth area A4.

[0155] In other embodiments, only the first metal grid 14 may be included without including the second metal grid 13 .

[0156] The first filter layer 11 , the second metal grid 13 and the first metal grid 14 in the first filter layer 11 are formed before the second filter layer 12 and the first metal grid 14 in the second filter layer 12 .

[0157] The first filter layer 11 may be formed first, and then the second metal grid 13 and the first metal grid 14 in the first filter layer 11 are formed; or, the second metal grid 13 and the first metal grid 14 in the first filter layer 11 are formed first, and then the first filter layer 11 is formed; the second filter layer 12 may be formed first, and then the first metal grid 14 in the second filter layer 12 is formed; or, the first metal grid 14 in the second filter layer 12 is formed first, and then the second filter layer 12 is formed.

[0158] The first filter layer 11 , the second filter layer 12 , the second metal grid 13 and the first metal grid 14 may be formed by using deposition and etching processes well known to those skilled in the art.

[0159] like Figure 7 As shown, when the incident light L1 of a certain wavelength is incident on the upper surface of the second filter layer 12 above one of the first area A1, the second area A2, the third area A3 and the fourth area A4, taking the incident light L1 on the upper surface of the second filter layer 12 above the first area A1 as an example, the second filter layer 12 enhances the transmission of the first color light in the direction close to the substrate 10, so that the first color light fully enters the upper surface of the first filter layer 11 in the first area A1, and the first filter layer 11 in the first area A1 is incident on the upper surface of the second filter layer 12 in the direction away from the substrate 10. The first color light is enhanced and reflected, so that the first color light fully enters the lower surface of the second filter layer 12 above the first area A1, and the second filter layer 12 enhances the reflection of the first color light in the direction close to the substrate 10, so that the first color light is repeatedly enhanced and reflected between the first filter layer 11 and the second filter layer 12; because the second metal grid 13 does not enter the second filter layer 12, the first color light that finally does not enter the first area A1 will have a probability of entering the second area A2, the third area A3, and the fourth area A4 (such as Figure 7L10 in the first region A1, the first color filter layer 11 in the second region A2, the third region A3 and the fourth region A4 can transmit the first color light, so that in a sufficiently long time (for example, the time of a single exposure), the first color light will enter the pixel below at least one of the second region A2, the third region A3 and the fourth region A4 after a sufficiently long time of enhanced reflection, so that the first color light entering the second filter layer 12 above the single whole formed by the first region A1, the second region A2, the third region A3 and the fourth region A4 can be fully transmitted into the four pixels below the single whole formed by the first region A1, the second region A2, the third region A3 and the fourth region A4. In the first region A1, the light of other colors except the first color light in the mixed color light is directly transmitted downward into the pixel through the second filter layer 12 and the first filter layer 11.

[0160] As can be seen from the above, since the refractive index of the second light-transmitting material layer 112 in the first light-filtering layer 11 is greater than the refractive index of the first light-transmitting material layer 111 in the first light-filtering layer 11, the first light-filtering layer 11 located in the first area A1, the second area A2, the third area A3, and the fourth area A4 have different optical thicknesses, so that the first area A1 allows other color lights except the first color light in the mixed color light to pass through, the second area A2 or the fourth area A4 allows other color lights except the second color light in the mixed color light to pass through, and the third area A3 or the fourth area A4 allows other color lights except the second color light in the mixed color light to pass through. Area A3 allows light of other colors except the third color in the mixed color light to pass through, that is, light of one color in the mixed color light incident on the first filter layer 11 of each area is reflected, and light of other colors in the mixed color light incident on the first filter layer 11 of each area are transmitted into the pixel, and each pixel loses light of one color. Compared with the traditional Bayer model in which the first filter layer 11 in each area only transmits light of one color and absorbs light of other colors, the first filter layer 11 of the present invention improves the photon transmittance, reduces the loss of photons, and thereby improves the quantum efficiency.

[0161] Furthermore, in the present invention, since the second filter layer 12 is formed above the first area A1, the second area A2, the third area A3, and the fourth area A4, the second filter layer 12 above the first area A1 can allow the first color light that has not entered the first area A1 to enter at least one of the second area A2, the third area A3, and the fourth area A4, the second filter layer 12 above the second area A2 or the fourth area A4 can allow the second color light that has not entered the second area A2 or the fourth area A4 to enter at least one of the first area A1 and the third area A3, and the second filter layer 12 above the third area A3 can allow the second color light that has not entered the second area A2 or the fourth area A4 to enter at least one of the first area A1 and the third area A3. The third color light that has not entered the third area A3 can enter at least one of the first area A1, the second area A2, and the fourth area A4, that is, the light of the corresponding color lost by the first filter layer 11 in a certain area can enter other areas and be transmitted into the pixels below the other areas, thereby making the mixed color light of the second filter layer 12 incident on the single whole formed by the first area A1, the second area A2, the third area A3 and the fourth area A4 can all enter the four pixels below, that is, the mixed color light incident on the filter layer can be completely transmitted into the pixel, realizing full photon absorption without photon loss, and greatly improving the quantum efficiency.

[0162] In one embodiment, the exposure intensity of each color of the pixels under each area can be calculated, and the photosensitive device in the pixel under each area can also sense the component of the corresponding color, so that the color of the four pixels under the whole composed of the first area A1, the second area A2, the third area A3 and the fourth area A4 can be inferred. Since there is no photon loss for the four pixels under the whole composed of the first area A1, the second area A2, the third area A3 and the fourth area A4, all the photons entering the four pixels are converted into photoelectrons by the photosensitive device, so that there is no color loss for the four pixels under the whole composed of the first area A1, the second area A2, the third area A3 and the fourth area A4, and the four pixels under the whole composed of the first area A1, the second area A2, the third area A3 and the fourth area A4 obtain completely real colors, thereby realizing a full-color image sensor. In the existing method, color restoration is achieved through an algorithm based on the data of adjacent pixels, resulting in color loss, and the obtained color is not real.

[0163] In summary, the manufacturing method of the image sensor provided by the present invention includes: providing a substrate; forming a filter layer on the substrate, the filter layer includes a first filter layer and a second filter layer, the first filter layer includes a first light-transmitting material layer and a second light-transmitting material layer, the first light-transmitting material layer is closer to the substrate than the second light-transmitting material layer, the refractive index of the second light-transmitting material layer is greater than the refractive index of the first light-transmitting material layer, the first filter layer includes a first region, a second region, a third region, and a fourth region, the first region, the second region, the third region, and the fourth region are adjacent to each other in sequence, the first filter layer located in the first region, the second region, the third region, and the fourth region has different optical thicknesses, the first region allows other color lights other than the first color light in the mixed color light to pass through, the second region or the fourth region allows other color lights other than the second color light in the mixed color light to pass through, and the third region allows other color lights other than the third color light in the mixed color light to pass through; the second filter layer is located above the first region, the second region, the third region, and the fourth region. The manufacturing method of the image sensor of the present invention greatly improves the quantum efficiency.

[0164] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. An image sensor, characterized in that: include: substrate; A filter layer is formed on the substrate, the filter layer includes a first filter layer and a second filter layer, the first filter layer includes a first light-transmitting material layer and a second light-transmitting material layer, the first light-transmitting material layer is closer to the substrate than the second light-transmitting material layer, the refractive index of the second light-transmitting material layer is greater than the refractive index of the first light-transmitting material layer, the first filter layer includes a first area, a second area, a third area, and a fourth area, the first area, the second area, the third area, and the fourth area are adjacent to each other in sequence, the first filter layer located in the first area, the second area, the third area, and the fourth area has different optical thicknesses, the first area allows other color light except the first color light in the mixed color light to pass through, the second area or the fourth area allows other color light except the second color light in the mixed color light to pass through, and the third area allows other color light except the third color light in the mixed color light to pass through; the second filter layer is located above the first area, the second area, the third area, and the fourth area.

2. The image sensor according to claim 1, wherein: The first filter layer includes the first light-transmitting material layer and the second light-transmitting material layer which are periodically and alternately stacked. The first light-transmitting material layer in each period is closer to the substrate than the second light-transmitting material layer. The number of the periodic alternating stacking periods is greater than or equal to 3.

3. The image sensor according to claim 1, wherein: The second filter layer comprises the fourth light-transmitting material layer and the fifth light-transmitting material layer which are periodically and alternately stacked, the refractive index of the fourth light-transmitting material layer is greater than the refractive index of the fifth light-transmitting material layer, the fourth light-transmitting material layer in each period is closer to the substrate than the fifth light-transmitting material layer, and the number of the periodic alternating stacking periods is greater than or equal to 3; A third light-transmitting material layer is formed between the fourth light-transmitting material layer and the second light-transmitting material layer, and the refractive index of the third light-transmitting material layer is smaller than the refractive indexes of the second light-transmitting material layer and the fourth light-transmitting material layer.

4. The image sensor according to claim 1, wherein: The image sensor further comprises: A first metal grid is formed in the first filter layer and the second filter layer, and the first metal grid is used to isolate adjacent filter layer sublayers from each other. The filter layer sublayers include the first filter layer in the first area, the second area, the third area, and the fourth area, and the second filter layer above the first filter layer corresponding to the first area, the second area, the third area, and the fourth area.

5. The image sensor according to claim 1, wherein: The image sensor further comprises: A pixel array is arranged in the substrate, pixels in the pixel array are formed correspondingly below the first area, the second area, the third area, and the fourth area, and adjacent pixels are isolated by an isolation structure.

6. The image sensor according to claim 1, wherein: The first area allows other color lights except the first color light in the mixed color light to pass through so that the pixels below the first area can calculate and output the complementary color of the first color light through an algorithm; The second area or the fourth area allows other color lights except the second color light in the mixed color light to pass through so that the pixels below the second area or the fourth area can calculate and output the complementary color of the second color light through an algorithm; The third area allows other color lights except the third color light in the mixed color light to pass through so that the pixels below the third area can output the complementary color of the third color light through algorithm calculation.

7. The image sensor according to claim 6, wherein: The first color light that has not entered the first area enters at least one of the second area, the third area, and the fourth area; The second color light that has not entered the second area or the fourth area enters at least one of the first area and the third area; The third color light that has not entered the third area enters at least one of the first area, the second area, and the fourth area.

8. A method for manufacturing an image sensor, characterized in that: include: providing a substrate; A filter layer is formed on the substrate, the filter layer includes a first filter layer and a second filter layer, the first filter layer includes a first light-transmitting material layer and a second light-transmitting material layer, the first light-transmitting material layer is closer to the substrate than the second light-transmitting material layer, the refractive index of the second light-transmitting material layer is greater than the refractive index of the first light-transmitting material layer, the first filter layer includes a first region, a second region, a third region, and a fourth region, the first region, the second region, the third region, and the fourth region are adjacent to each other in sequence, the first filter layer located in the first region, the second region, the third region, and the fourth region has different optical thicknesses, the first region allows other color light except the first color light in the mixed color light to pass through, the second region or the fourth region allows other color light except the second color light in the mixed color light to pass through, and the third region allows other color light except the third color light in the mixed color light to pass through; the second filter layer is located above the first region, the second region, the third region, and the fourth region.

9. The method for manufacturing an image sensor according to claim 8, wherein: The first filter layer includes the first light-transmitting material layer and the second light-transmitting material layer which are periodically and alternately stacked. The first light-transmitting material layer in each period is closer to the substrate than the second light-transmitting material layer. The number of the periodic alternating stacking periods is greater than or equal to 3.

10. The method for manufacturing an image sensor according to claim 8, characterized in that: The second filter layer comprises the fourth light-transmitting material layer and the fifth light-transmitting material layer which are periodically and alternately stacked, the refractive index of the fourth light-transmitting material layer is greater than the refractive index of the fifth light-transmitting material layer, the fourth light-transmitting material layer in each period is closer to the substrate than the fifth light-transmitting material layer, and the number of the periodic alternating stacking periods is greater than or equal to 3; A third light-transmitting material layer is formed between the fourth light-transmitting material layer and the second light-transmitting material layer, and the refractive index of the third light-transmitting material layer is smaller than the refractive indexes of the second light-transmitting material layer and the fourth light-transmitting material layer.

11. The method for manufacturing an image sensor according to claim 8, wherein: The method for manufacturing the image sensor further includes: A first metal grid is formed in the first filter layer and the second filter layer, and the first metal grid is used to isolate adjacent filter layer sub-layers from each other. The filter layer sub-layers include the first filter layer in the first area, the second area, the third area, and the fourth area, and the second filter layer above the first filter layer corresponding to the first area, the second area, the third area, and the fourth area.

12. The method for manufacturing an image sensor according to claim 8, wherein: Before forming the filter layer on the substrate, the method for manufacturing the image sensor further includes: A pixel array is formed, and the array is arranged in the substrate. Pixels in the pixel array are correspondingly formed below the first area, the second area, the third area, and the fourth area, and adjacent pixels are isolated by an isolation structure.

13. The method for manufacturing an image sensor according to claim 8, wherein: The first area allows other color lights except the first color light in the mixed color light to pass through so that the pixels below the first area can calculate and output the complementary color of the first color light through an algorithm; The second area or the fourth area allows other color lights except the second color light in the mixed color light to pass through so that the pixels below the second area or the fourth area can calculate and output the complementary color of the second color light through an algorithm; The third area allows other color lights except the third color light in the mixed color light to pass through so that the pixels below the third area can output the complementary color of the third color light through algorithm calculation.

14. The method for manufacturing an image sensor according to claim 13, wherein: The first color light that has not entered the first area enters at least one of the second area, the third area, and the fourth area; The second color light that has not entered the second area or the fourth area enters at least one of the first area and the third area; The third color light that has not entered the third area enters at least one of the first area, the second area, and the fourth area.

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