CN212343888U - Image sensor and electronic equipment - Google Patents

Abstract

The utility model provides an image sensor and electronic equipment. The image sensor comprises a pixel array, wherein the pixel array comprises an imaging pixel and a phase focusing pixel; the image sensor comprises a semiconductor substrate, a filter layer and a micro-lens layer which are sequentially arranged; a plurality of photosensitive devices, one imaging pixel comprising one photosensitive device, one phase-in-focus pixel comprising at least one photosensitive device; the filter layer comprises a red filter unit, a green filter unit, a blue filter unit and a white filter unit; the microlens layer includes first microlenses and second microlenses, one first microlens overlapping one imaging pixel and one second microlens overlapping at least one phase-focusing pixel; the photosensitive device overlaps the white filter cell in the phase-focus pixel. The utility model discloses can improve the phase place and focus the photosensitivity of pixel, promote the performance of focusing under the low illumination.

Description

Image sensor and electronic equipment

Technical Field

The utility model relates to an image sensing technical field especially relates to an image sensor and electronic equipment.

Background

The greater the number of pixels in the image sensor, the more image information it can record, and the better the imaging effect of the image. When the overall size of the image sensor is fixed, the size of each pixel needs to be set relatively small in order to ensure a sufficient number of pixels. In an image sensor adopting a phase focusing technology, focusing is firstly completed by depending on a phase focusing pixel to ensure the imaging quality during imaging, when the pixel size is smaller, the incident light flux which can be received by the corresponding light sensing device is limited, especially under the condition of low illumination, the light quantity which can be received by the phase focusing pixel is less, so that the photosensitive performance of the phase focusing pixel is reduced, the focusing performance is reduced, and the imaging quality of an image is influenced.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides an image sensor to the focusing performance descends under solving low illumination, influences the problem of image quality of formation of image.

In a first aspect, an embodiment of the present invention provides an image sensor, which includes a pixel array, where the pixel array includes an imaging pixel and a phase focusing pixel; further comprising:

a semiconductor substrate including a plurality of photosensitive devices, an imaging pixel including one photosensitive device, and a phase-focus pixel including at least one photosensitive device;

the filter layer is positioned on one side of the semiconductor substrate and comprises a plurality of filter units, and the filter units comprise a red filter unit, a green filter unit, a blue filter unit and a white filter unit;

the micro-lens layer is positioned on one side of the filter layer far away from the semiconductor substrate and comprises a first micro-lens and a second micro-lens, one first micro-lens is overlapped with one imaging pixel, and the other second micro-lens is overlapped with at least one phase focusing pixel; wherein the content of the first and second substances,

in the imaging pixel, the photosensitive device is overlapped with any one of the red filter unit, the green filter unit or the blue filter unit;

in a phase-in-focus pixel, a photosensitive device overlaps a white filter cell.

Further, the image sensor further includes a reflection grid including a plurality of openings, and the filter unit is located in the openings.

Further, the image sensor layer further comprises a first dielectric layer, and the first dielectric layer is located between the reflection grid and the filtering unit.

Further, the semiconductor substrate includes a plurality of isolation trenches, and the isolation trenches are located between two adjacent photosensitive devices.

Optionally, the pixel array includes focusing pixel groups, one focusing pixel group includes two adjacent phase focusing pixels, and one focusing pixel group overlaps with one second microlens.

Optionally, the pixel array includes focusing pixel groups, one focusing pixel group includes four phase focusing pixels arranged in 2 × 2, and one focusing pixel group overlaps with one second microlens.

Optionally, the image sensor further includes a light shielding layer, where the light shielding layer is located between the semiconductor substrate and the filter layer, and the light shielding layer includes a light shielding unit; in the phase focusing pixels, the light shielding unit overlaps with a partial region of the photosensor, and one phase focusing pixel overlaps with one second microlens.

Optionally, one phase focusing pixel includes two sub-focusing pixels, one sub-focusing pixel includes one photosensitive device, and the two sub-focusing pixels overlap with one second microlens.

Optionally, a white filtering unit overlaps a light sensing device.

In a second aspect, the present invention further provides an electronic device, including the image sensor provided by any embodiment of the present invention.

The embodiment of the utility model provides an image sensor and electronic equipment has following beneficial effect: the image focusing is realized based on a phase focusing mode, the filtering units in the phase focusing pixels are set to be white filtering units, and the white filtering units have better transmittance for light with different wavelengths. Compared with the color filtering unit arranged in the phase focusing pixel, the light quantity received by the photosensitive device can be improved, especially under low illumination, enough light can still be ensured to be received by the photosensitive device in the phase focusing pixel, the photosensitivity of the phase focusing pixel is improved, the focusing performance under low illumination is improved, and the imaging quality under low illumination is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive labor.

Fig. 1 is a partial schematic top view of an image sensor according to an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view taken along line A-A' of FIG. 1;

FIG. 3 is a first curve of sensitivity to visible light before and after improvement of phase focusing pixels;

fig. 4 is a block diagram of an image sensor according to an embodiment of the present invention;

fig. 5 is another partial plan view of an image sensor provided in an embodiment of the present invention;

FIG. 6 is a schematic cross-sectional view taken along line B-B' of FIG. 5;

FIG. 7 is a schematic cross-sectional view taken along line B-B' of FIG. 5;

FIG. 8 is another schematic cross-sectional view taken along line A-A' of FIG. 1;

FIG. 9 is a second sensitivity curve for visible light before and after improvement of the phase focusing pixels;

FIG. 10 is a graph of pixel cross-talk before and after improvement;

fig. 11 is another partial plan view of an image sensor provided in an embodiment of the present invention;

fig. 12 is another partial plan view of an image sensor provided in an embodiment of the present invention;

fig. 13 is another partial plan view of an image sensor provided in an embodiment of the present invention;

fig. 14 is another partial plan view of an image sensor provided in an embodiment of the present invention;

fig. 15 is another partial plan view of an image sensor provided in an embodiment of the present invention;

FIG. 16 is a schematic cross-sectional view taken along line C-C' of FIG. 15;

fig. 17 is another partial plan view of an image sensor provided in an embodiment of the present invention;

fig. 18 is a schematic sectional view taken along line D-D' of fig. 17.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the embodiments of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The utility model provides an image sensor and electronic equipment sets up the pixel of formation of image and the pixel of focusing of phase place in image sensor's pixel array, at first realizes focusing based on the method of focusing of phase place when the formation of image, then images. The white filtering unit is adopted to replace the color filtering unit in the phase focusing pixel, the white filtering unit has higher transmittance for the light of three colors of red, green and blue in the ambient light, compared with the color filtering unit arranged in the phase focusing pixel, the light quantity received by the photosensitive device can be improved, especially under low illumination, enough light can still be ensured to be received by the photosensitive device in the phase focusing pixel, thereby improving the focusing performance under low illumination and further improving the imaging quality under low illumination. The present invention will be illustrated in detail in specific examples.

Fig. 1 is a partial top view of an image sensor according to an embodiment of the present invention. Fig. 2 is a schematic cross-sectional view at the position of line a-a' in fig. 1.

As shown in fig. 1, the image sensor includes a pixel array (only a partial pixel array is illustrated in the figure) including an imaging pixel 10 and a phase-focusing pixel 20; the imaging pixel 10 schematically illustrated in the figure includes a red pixel 31, a green pixel 32, and a blue pixel 33, where the red pixel 31 includes a red filter unit, the green pixel 32 includes a green filter unit, and the blue pixel 33 includes a blue filter unit. Fig. 1 is schematically illustrated in a bayer array arrangement.

As shown in fig. 2, the image sensor includes: a semiconductor substrate 101, the semiconductor substrate 101 comprising a plurality of photosensitive devices 11, an imaging pixel 10 comprising one photosensitive device 11, and a phase-focus pixel 20 comprising at least one photosensitive device 11. The photosensitive device 11 is a photodiode, the photodiode may be formed by implanting N-type elements into a P-type silicon substrate, or may be formed by implanting P-type elements into an N-type silicon substrate, and the photosensitive device 11 is only illustrated in a simplified block diagram.

A filter layer 102 on one side of the semiconductor substrate 101, the filter layer 102 including a plurality of filter units including a red filter unit 121, a green filter unit 122, a blue filter unit 123, and a white filter unit 124; a microlens layer 103, the microlens layer 103 is located on a side of the filter layer 102 away from the semiconductor substrate 101, the microlens layer 103 includes first microlenses 131 and second microlenses 132, one first microlens 131 overlaps one imaging pixel 11, and one second microlens 132 overlaps at least one phase-focusing pixel 20, for example, one second microlens 132 overlaps two phase-focusing pixels 20; as illustrated in fig. 2, the height of the second microlenses 132 is greater than the height of the first microlenses 131. Wherein the content of the first and second substances,

in the imaging pixel 10, the photosensor 11 overlaps any one of the red filter unit 121, the green filter unit 122, or the blue filter unit 123; that is, the red filter unit 121 overlaps the photosensitive device 11 in the red pixel 31, the green filter unit 122 overlaps the photosensitive device 11 in the green pixel 32, and the blue filter unit 123 overlaps the photosensitive device 11 in the blue pixel 33. In the phase-focus pixel 20, the photosensor 11 overlaps the white filter unit 124.

Fig. 2 also illustrates that a dielectric layer 104 is disposed between the semiconductor substrate 101 and the filter layer 102, the dielectric layer 104 may be made of silicon oxide or silicon nitride, and the dielectric layer 104 can be used to improve adhesion between the semiconductor substrate 101 and the filter layer 102, and is also beneficial to reducing dark current and improving performance of the photosensitive device.

The image sensor further comprises a circuit layer, optionally, the circuit layer is located on one side, away from the filter layer, of the semiconductor substrate, and the circuit layer is provided with a driving circuit, and the driving circuit is used for controlling exposure of the pixel array.

The utility model discloses after the improvement, the phase place is focused the filtering unit in the pixel and is white filtering unit, to adopting the utility model discloses the sensitivity of the pixel is focused to the phase place after the scheme improvement has carried out the emulation test to the filtering unit in the pixel is focused to the phase place is green filtering unit for example before the improvement, adopts the same light source to shine the pixel is focused to the phase place around the improvement, tests the sensitivity that the pixel was focused to two kinds of phase places.

Comparative example 1: the filtering unit in the phase focusing pixel is a green filtering unit; embodiment 1 of the present case: the filtering unit in the phase focusing pixel is a white filtering unit. The phase focusing pixels before and after improvement are only different from the filtering unit during testing, other structures are the same, and one microlens is overlapped with two phase focusing pixels at the same time in each structure, namely, one microlens is overlapped with two phase focusing pixels at the same time in the comparative example 1; in embodiment 1, one microlens overlaps two phase-focus pixels at the same time. The light source used in the test is a relative color temperature light source, the light source value is 6500K, the two phase focusing pixels before and after improvement both comprise an infrared filter, the cut-off wavelength of the infrared filter is 650nm, namely, the light with the wavelength of more than 650nm can be inhibited by the infrared filter. Fig. 3 is a graph showing the sensitivity to visible light before and after the improvement of the phase focusing pixel. As shown in fig. 3, the abscissa is the wavelength (nm); the ordinate is a normalized response value, which represents the normalized response of the pixel to light with different wavelengths, i.e. represents the amount of electrical signals after converting light into electrical signals, and the more electrical signals after converting the same light, the better the sensitivity of the pixel. The normalized curve of the comparative example 1 to visible light is curve a; the normalized curve of example 1 of the present application to visible light is curve b in the figure. As for the comparison example 1 in which the filter unit in the phase focusing pixel is a green filter unit, it can be seen that green photons in the light source can be received by the photosensitive device through the green filter unit and then converted into electrical signals by the optical signal conversion layer, so that the sensitivity of the optical signal conversion layer to light in the wavelength band of 500-550 nm is high. The sensitivity of the phase focusing pixel in the comparative example 1 to the light in the wavelength band of 400-480 nm is less than 50%, and the sensitivity of the phase focusing pixel in the example 1 is more than 80%. Although the intensity of light in the wavelength range of 600nm or more is reduced by the infrared filter, the sensitivity of the phase focusing pixel in embodiment 1 to light in the wavelength range of 600nm or more is still higher than that of the phase focusing pixel before improvement. Adopt the utility model discloses the scheme improves the back, and white light filtering unit in the pixel is focused to the phase place all has better transmissivity to the light of different wavelengths, and red photon, blue photon and green photon can both be received the light signal conversion layer signal of telecommunication by photosensitive device behind the white light filtering unit, and the phase place after the improvement is focused the photon that the pixel was collected and is increased, and its photosensitivity is showing and is improving.

The embodiment of the utility model provides an image sensor realizes the image based on the phase place mode of focusing and focuses, focuses the phase place and sets the filter unit to white filter unit in the pixel, and white filter unit all has better transmissivity to the light of different wavelengths. Compared with the color filtering unit arranged in the phase focusing pixel, the light quantity received by the photosensitive device can be improved, especially under low illumination, enough light can still be ensured to be received by the photosensitive device in the phase focusing pixel, the photosensitivity of the phase focusing pixel is improved, the focusing performance under low illumination is improved, and the imaging quality under low illumination is improved.

Optionally, in the embodiment of the present application, the density of the phase focusing pixels in the pixel array is 1% to 5%, and the density of the phase focusing pixels satisfies a certain range, so as to ensure the stability of phase focusing.

Fig. 4 is a block diagram of an embodiment of the present invention, and as shown in fig. 4, the image sensor includes: pixel array 901, row driver circuit 902, column driver circuit 903, control circuit 904, data acquisition module 905, and image processing module 906. The control circuit 904 is configured to control the row driving circuit 902 and the column driving circuit 903 respectively, so as to control exposure of the pixel array, where after the exposure of the pixel array, the photosensitive devices in the pixels convert received optical signals into electrical signals; the data acquisition module 905 is configured to collect an electrical signal generated by each pixel, and send the electrical signal to the image processing module 906 for processing, so as to finally generate image information.

Further, fig. 5 is another partial plan view of the image sensor according to the embodiment of the present invention. Fig. 6 is a schematic cross-sectional view taken along line B-B' of fig. 5. As shown in fig. 5, the image sensor further includes a reflective grid 105, the reflective grid 105 includes a plurality of openings (not labeled in fig. 5), the reflective grid 105 is illustrated by a thick black solid line, it can be seen that the reflective grid 105 corresponds to a grid structure in a top view, the reflective grid 105 includes a first reflective strip 1051 extending along the first direction x and a second reflective strip 1052 extending along the second direction y, and the first reflective strip 1051 and the second reflective strip 1052 intersect to define a plurality of openings. The filter units are located in the openings, and the figure shows that the red filter unit 121 is located in one opening, the green filter unit 122 is located in one opening, the blue filter unit 123 is located in one opening, and the white filter unit 124 is located in one opening. I.e. the reflective grid 105 is used to space the filter cells of different colors.

As shown in the cross-sectional view of fig. 6, which is a simplified schematic diagram showing a part of the light path, after the reflection grids are disposed between the filter units of different colors, taking the phase-focusing pixel 20 as an example, a part of the large-angle light rays penetrating through the second microlens 132 and entering the white filter unit 124 will be reflected after being emitted to the reflection grid 105. The direction perpendicular to the semiconductor substrate 101 is e, and the included angle between the large-angle light and the direction e is large, so that the light may enter the white filter unit through the second microlens 132 and then emit to the adjacent imaging pixel 10, which may cause crosstalk of the light. In the embodiment, the crosstalk of the large-angle light rays on the phase focusing pixels to the imaging pixels can be improved through the arrangement of the reflection grids, and the reflection grids can reflect the large-angle light rays back to the original pixels, so that the utilization rate of the large-angle light rays is improved, and the light sensitivity of the phase focusing pixels can also be improved. According to the same principle, the reflection grids are arranged between the color filter units of the adjacent imaging pixels, so that light crosstalk between the imaging pixels can be inhibited, the light sensitivity of the imaging pixels is improved, and the integral imaging quality of the image sensor can be improved.

Optionally, the material for manufacturing the reflection grid includes any one or more of aluminum, chromium, molybdenum and titanium.

Further, the image sensor layer further includes a plurality of media portions, and fig. 7 is a schematic cross-sectional view taken along line B-B' of fig. 5. As shown in fig. 7, the dielectric part 106 is located between the reflection grid 105 and the filter unit. In the figure, a dielectric portion 106 is provided between the reflection grid 105 and the red filter 121, a dielectric portion 106 is provided between the reflection grid 105 and the green filter 122, a dielectric portion 106 is provided between the reflection grid 105 and the blue filter 123, and a dielectric portion 106 is also provided between the reflection grid 105 and the white filter 124. When manufacturing, the reflection grid is firstly manufactured, then the dielectric material is covered on the reflection grid to form a plurality of dielectric parts, and then the corresponding filtering units are manufactured. The dielectric part can be made of silicon nitride or silicon oxide, and is used for increasing the bonding performance between the reflection grid and the filtering unit and ensuring the stability of the structure of the image sensor.

In one implementation, FIG. 8 is another cross-sectional view taken at line A-A' of FIG. 1. As shown in fig. 8, the semiconductor substrate 101 includes a plurality of isolation trenches 107, the isolation trenches 107 being located between two adjacent photosensitive devices 11. Optionally, the depth of the isolation trench is about 2 μm. During manufacturing, a plurality of isolation trenches 107 may be formed by etching the semiconductor substrate 101, and then the isolation trenches 107 are filled with oxide or polysilicon, so that the interface between the filling material of the isolation trenches and the semiconductor substrate has a certain reflection effect on light. As an example of the optical path illustrated in the figure, taking the phase-focusing pixel 20 as an example, a part of the large-angle light above the phase-focusing pixel 20 is reflected after being emitted to the isolation trench 107 and then received by the photosensitive device 11 in the phase-focusing pixel 20, so that the part of the large-angle light does not enter the photosensitive device 11 of the adjacent pixel to cause light crosstalk, and the part of the large-angle light is reflected and then received by the photosensitive device 11 in the phase-focusing pixel 20 again, which can improve the optical sensitivity of the phase-focusing pixel. According to the same principle, the isolation grooves arranged between the photosensitive devices corresponding to the adjacent imaging pixels can inhibit light crosstalk between the imaging pixels, improve the light sensitivity of the imaging pixels and improve the integral imaging quality of the image sensor.

Further, the utility model discloses the sensitivity and the pixel condition of crosstalking of the pixel of focusing in the image sensor to increasing isolation slot have all carried out the simulation experiment and have verified.

Fig. 9 is a second sensitivity curve for visible light before and after the phase-focusing pixel improvement. Comparative example 2: in the existing isolation technology, a metal block is used between adjacent pixels to suppress crosstalk of light, wherein when viewed from a top view angle, the metal block is located between two adjacent pixels, the metal block is located between filter layers of a semiconductor substrate at a film position, and the metal block also has a certain reflection effect on light. Embodiment 2 of the present case: isolation trenches are disposed between adjacent photosensitive devices. The other structures of the comparative example 2 and the embodiment 2 are the same, and in the structures, one microlens is overlapped with two phase focusing pixels at the same time. The test was conducted by irradiating comparative example 2 and example 2 of this example with the same light source. As shown in fig. 9, the abscissa is the microlens height (μm) overlapping the phase-in-focus pixel, and the ordinate is the normalized response value. The normalized curve of the control example 2 for visible light is curve c in the figure; the normalized curve of example 2 in this case for visible light is curve d in the figure. It can be seen that in multiple sets of test experiments in which the heights of the microlenses vary from 1 μm to 2.5 μm, the normalized values obtained in the embodiment 2 in the present application are all greater than those obtained in the comparative example 2, and the photosensitivity of the embodiment 2 in the present application can be improved by more than 20% compared with that of the comparative example 2.

Fig. 10 is a graph of improved front-to-back pixel crosstalk. Comparative example 3: the same isolation technique as in comparative example 2, the filter unit in the phase-focus pixel is set as a white filter unit. Embodiment 3 of the present application: an isolation groove is arranged between adjacent photosensitive devices, and the filtering unit in the phase focusing pixel is a white filtering unit. In both the comparative example 3 and the present example 3, one microlens overlaps two phase focus pixels at the same time. The test was conducted by irradiating comparative example 3 and example 3 of this example with the same light source. As shown in fig. 10, the abscissa is the height (μm) of the microlens overlapping the phase-focused pixel, and the ordinate is the isolation degree of the adjacent pixels, and the larger the ordinate is, the smaller the mutual influence between the pixels is, the smaller the crosstalk is, that is, the stronger the crosstalk resisting capability of the pixel is. The curve of the isolation degree between the phase focusing pixel and its neighboring pixel in the comparison example 3 is curve g in the figure, the curve of the isolation degree between the imaging pixel (including the green filter unit) and its neighboring pixel in the comparison example 3 is curve h in the figure, the curve of the isolation degree between the phase focusing pixel and its neighboring pixel in the embodiment 3 in the present case is curve m in the figure, and the curve of the isolation degree between the imaging pixel (including the green filter unit) and its neighboring pixel in the embodiment 3 in the present case is curve n in the figure, and it can be seen from the curves in the figures that the crosstalk resistance of the phase focusing pixel and the imaging pixel is significantly improved after the design of the isolation trench in the present case is adopted.

In some alternative embodiments, the pixel array includes focusing pixel groups, and one focusing pixel group includes 2 or 4 phase focusing pixels.

With continued reference to fig. 1 and 2, two adjacent phase focus pixels 20 form a focus pixel group. One focusing pixel group overlaps one second microlens 132, i.e., one second microlens 132 overlaps two phase focusing pixels. In the different focusing pixel groups in fig. 1, the arrangement directions of the two phase focusing pixels are the same.

In another embodiment, fig. 11 is another partial plan view of an image sensor provided in an embodiment of the present invention. As shown in fig. 11, still taking the bayer array arrangement as an example for illustration, a first direction x and a second direction y intersecting each other are also illustrated, and two focusing pixel groups 50 (only one is labeled) are illustrated, and each focusing pixel group 50 includes two phase focusing pixels 20. One focusing pixel group 50 overlaps one second microlens 132. Unlike the embodiment of fig. 1, in the embodiment of fig. 11, two phase-focusing pixels 20 are arranged in the first direction x in one focusing pixel group 50, and two phase-focusing pixels 20 are arranged in the second direction y in the other focusing pixel group 50.

In an embodiment that one focusing pixel group includes two phase focusing pixels, the arrangement mode of two adjacent phase focusing pixels in the focusing pixel group, the position of the focusing pixel group in the pixel array, and the setting density of the phase focusing pixels are not limited in the present application, and in practice, the larger the density of the phase focusing pixels is, the better the focusing performance of the image sensor is. The above parameters can be designed according to specific requirements in practice.

In another embodiment, as shown in fig. 12, fig. 12 is another partial plan view of an image sensor provided in an embodiment of the present invention. Still taking the bayer arrangement as an example, the pixel array includes focusing pixel groups 50, one focusing pixel group 50 includes four phase focusing pixels 20 arranged 2 × 2, and one focusing pixel group 20 overlaps one second microlens 132.

In another embodiment, fig. 13 is another partial plan view of an image sensor provided in an embodiment of the present invention. As shown in fig. 13, a Quad bayer arrangement (Quad bayer) is illustrated, in which the pixel array includes a focusing pixel group 50, one focusing pixel group 50 includes four phase focusing pixels 20 in a 2 × 2 arrangement, and one focusing pixel group 20 overlaps one second microlens 132.

In another embodiment, fig. 14 is another partial plan view of an image sensor provided in an embodiment of the present invention. As shown in fig. 14, a quad bayer arrangement is illustrated, in this embodiment, each 4 × 4 pixel array includes a focusing pixel group 50, and the phase focusing pixel density reaches 25%, which can significantly improve the stability of phase focusing.

Specifically, in another embodiment, fig. 15 is another partial plan view of the image sensor provided in the embodiment of the present invention. Fig. 16 is a schematic cross-sectional view taken along line C-C' of fig. 15. Referring to fig. 15 and 16 simultaneously, the image sensor further includes a light shielding layer 108, the light shielding layer 108 being located between the semiconductor substrate 101 and the filter layer 102, the light shielding layer 108 including a light shielding element 1081; in the phase-focus pixel 20, the light shielding unit 1081 overlaps a partial area of the photosensor 11, and one phase-focus pixel 20 overlaps one second microlens 132. The light-shielding sub-portion 1082 is also illustrated, the light-shielding sub-portion 1082 is located between adjacent pixels, the light-shielding sub-portion 1082 may be located in the light-shielding layer 108, and the light-shielding sub-portion 1082 and the light-shielding unit 1081 may be fabricated in the same process. The position of the phase-in-focus pixel in fig. 15 is only schematically represented. In addition, as illustrated in the drawing, in the partial phase-focus pixel 20, the light shielding unit 1081 overlaps with the left area of the photosensor 11; and in the partial phase-focus pixel 20, the light shielding unit 1081 overlaps with the right area of the photosensor 11. In this embodiment, the light shielding unit 1081 overlaps with a partial region of the photosensitive device 11, the phase focusing pixel 20 is a half-pixel shielding pixel, the half-pixel shielding pixel is used as the phase focusing pixel, the color filtering unit above the half-pixel shielding pixel is replaced with a white filtering unit, and the white filtering unit has a better transmittance for light with different wavelengths, so that the light quantity received by the photosensitive device can be improved, especially under low light, enough light can still be ensured to be received by the photosensitive device in the phase focusing pixel, and the photosensitivity of the phase focusing pixel is improved, thereby improving the focusing performance under low light. In addition, in this embodiment, the light-shielding sub-portions can be formed in the process of forming the light-shielding units, and the light-shielding sub-portions are located between adjacent pixels, so that light emitted to the adjacent pixels in the pixels can be shielded, crosstalk between the adjacent pixels can be improved, and the imaging effect can be further improved. In addition, fig. 16 also illustrates an isolation trench 107 located between adjacent photosensitive devices 11, where the isolation trench can suppress crosstalk of light between pixels, improve light sensitivity of the pixels, and further improve the overall imaging quality of the image sensor.

Specifically, in another embodiment, fig. 17 is another partial plan view of the image sensor provided in the embodiment of the present invention. Fig. 18 is a schematic sectional view taken along line D-D' of fig. 17. As illustrated with simultaneous reference to fig. 17 and 18, one phase-focus pixel 20 includes two sub-focus pixels 21, one sub-focus pixel 21 includes one photosensitive device 11, and two sub-focus pixels 21 overlap one second microlens 132. In this embodiment, the phase focusing pixel 20 is a dual-core pixel, the dual-core pixel is used to realize phase focusing, the color filtering unit above the dual-core pixel is replaced with a white filtering unit, the white filtering unit has better transmittance for light with different wavelengths, so that the light quantity received by the photosensitive device can be increased, especially under low illumination, enough light can still be received by the photosensitive device in the phase focusing pixel, the photosensitivity of the phase focusing pixel is increased, and the focusing performance under low illumination is improved. In addition, fig. 18 also illustrates the isolation trench 107 located between the adjacent photosensitive devices 11, where the isolation trench can suppress crosstalk of light between pixels, improve light sensitivity of the pixels, and further improve the overall imaging quality of the image sensor.

In the above embodiments, one white filter unit is overlapped with one photosensitive device, and in some embodiments, one white filter unit may also be overlapped with two photosensitive devices, or overlapped with a plurality of photosensitive devices. In an embodiment where the pixel array includes a focusing pixel group, and the focusing pixel group includes two adjacent phase focusing pixels, the white filter units in the two adjacent phase focusing pixels may be connected, that is, one white filter unit overlaps two photosensitive devices. In an embodiment where the pixel array includes a focusing pixel group, and the focusing pixel group includes 2 × 2 adjacent phase focusing pixels, the white filter units in the 2 × 2 phase focusing pixels may be connected, that is, one white filter unit overlaps with four photosensitive devices.

The embodiment of the utility model provides an electronic equipment is still provided, include the utility model discloses arbitrary embodiment provides an image sensor. The specific structure and principle of the image sensor are the same as those of the above embodiments, and are not described herein again, and the electronic device may be any imaging device, such as a mobile phone, a camera, a monitoring device, and the like.

Claims (10)

1. An image sensor comprising a pixel array comprising imaging pixels and phase-in-focus pixels; the image sensor includes:

a semiconductor substrate comprising a plurality of photosensitive devices, one of said imaging pixels comprising one of said photosensitive devices, one of said phase-focus pixels comprising at least one of said photosensitive devices;

the filter layer is positioned on one side of the semiconductor substrate and comprises a plurality of filter units, and the filter units comprise a red filter unit, a green filter unit, a blue filter unit and a white filter unit;

a microlens layer on a side of the filter layer remote from the semiconductor substrate, the microlens layer including first and second microlenses, one of the first microlenses overlapping one of the imaging pixels and one of the second microlenses overlapping at least one of the phase-focus pixels; wherein the content of the first and second substances,

in the imaging pixel, the photosensitive device overlaps with any one of the red filter unit, the green filter unit or the blue filter unit;

in the phase-focusing pixel, the photosensitive device overlaps with the white filter unit.

2. The image sensor of claim 1,

the image sensor further includes a reflective grid including a plurality of openings, and the filtering unit is located within the openings.

3. The image sensor of claim 2,

the image sensor layer further includes a plurality of dielectric portions between the reflection grid and the filtering unit.

4. The image sensor of claim 1, wherein the semiconductor substrate comprises a plurality of isolation trenches, the isolation trenches being located between two adjacent photosensitive devices.

5. The image sensor of claim 1,

the pixel array comprises focusing pixel groups, one focusing pixel group comprises two adjacent phase focusing pixels, and one focusing pixel group is overlapped with one second micro lens.

6. The image sensor of claim 1,

the pixel array comprises focusing pixel groups, one focusing pixel group comprises four phase focusing pixels arranged in 2 x 2, and one focusing pixel group is overlapped with one second micro lens.

7. The image sensor of claim 1,

the image sensor further comprises a light shielding layer, wherein the light shielding layer is positioned between the semiconductor substrate and the light filtering layer and comprises light shielding units;

in the phase focusing pixels, the light shielding unit overlaps with a partial region of the photosensitive device, and one of the phase focusing pixels overlaps with one of the second microlenses.

8. The image sensor of claim 1,

one of the phase focusing pixels includes two sub-focusing pixels, one of the sub-focusing pixels includes one of the photosensitive devices, and the two sub-focusing pixels overlap one of the second microlenses.

9. The image sensor of claim 1,

one of the white filter units overlaps one of the photosensors.

10. An electronic device characterized by comprising an image sensor according to any one of claims 1 to 9.

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