JP2012038768A - Solid-state imaging element and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid-state imaging element capable of performing pupil division while preventing decrease in sensitivity and occurrence of color mixture.SOLUTION: A solid-state imaging element 100 comprises: microlenses 10a, 11a, and 12a; photodiodes (PD) 21 each of which receives light condensed by each of the microlenses; and signal readout circuits 22 each of which reads out a signal corresponding to an electric charge generated at each of the PDs 21. The microlenses 10a, 11a, and 12a are provided on one side of a layer including the PDs 21, and the signal readout circuits 22 are provided on the other side of the layer. The microlens 11a (12a) comprises an upper convex lens shaped portion 11b (12b). The upper convex lens shaped portion 11b (12b) is eccentric with respect to the center of the microlens 11a (12a) and the transmittance thereof is higher than that of the outermost lens portion of the microlens 11a (12a).

Description

  The present invention relates to a solid-state imaging device and an imaging apparatus.

  A phase difference detection method is known as one of focus detection techniques. In this method, a pair of pupil division pixels that receive light beams that pass through different pupil regions of the photographing lens are provided, and the defocus amount of the photographing lens is detected by using signals from the pair of pupil division pixels. Is. As imaging devices to which the principle of such a phase difference detection method is applied, those described in Patent Documents 1 and 2 are known.

  The solid-state imaging device described in Patent Document 1 forms a pair of pupil division pixels by dividing a photoelectric conversion region below one microlens into two. However, in this configuration, the smaller the size, the more difficult the manufacture becomes, and color mixing tends to occur, resulting in lack of phase difference detection accuracy. Moreover, it lacks toughness with respect to various incident angles.

  Patent Document 2 describes a solid-state image sensor in which pupil dividing pixels are formed by decentering a light shielding film opening provided above a photoelectric conversion element. However, this configuration is premised on a configuration in which a light shielding film is provided above the photoelectric conversion element, and a back-illuminated imaging element or a photoelectric conversion layer stacked type imaging that does not require a light shielding film above the photoelectric conversion element. It cannot be easily applied to devices.

  The back-illuminated image sensor has a configuration that can realize an aperture ratio of 100% and does not require a light shielding film. If the light-shielding film is intentionally formed above the photoelectric conversion region, the distance between the photoelectric conversion region and the microlens above the photoelectric conversion region is increased, and there is a concern that sensitivity of all pixels may be reduced and color mixing may occur. In addition, it is necessary to add a step of forming a light shielding film, and there is a concern about an increase in manufacturing cost.

  The photoelectric conversion layer stacked type imaging device has a photoelectric conversion layer that converts light into electric charges stacked on a semiconductor substrate on which a signal readout circuit is formed, and a signal corresponding to the electric charges generated in the photoelectric conversion layer is transmitted to the semiconductor substrate. It is the structure read by the signal reading circuit formed in this. The photoelectric conversion layer-stacked image sensor is also configured to achieve an aperture ratio of 100%, similar to the back-illuminated image sensor. For this reason, a light shielding film is unnecessary, but if a light shielding film is provided, there is a concern that sensitivity is lowered, color mixing occurs, and manufacturing costs are increased.

  In recent years, the sensitivity improvement of a general single-plate solid-state image sensor has reached the limit, and back-illuminated image sensors and photoelectric conversion layer stacked image sensors that can dramatically improve the sensitivity have attracted attention. ing. However, a pixel structure for performing pupil division while preventing a decrease in sensitivity, occurrence of color mixing, and an increase in manufacturing cost has not been proposed so far in back-illuminated image sensors and photoelectric conversion layer stacked image sensors.

JP 2007-281296 A JP 2008-312073 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solid-state imaging device capable of performing pupil division while preventing a reduction in sensitivity and color mixing, and an imaging apparatus including the same.

The solid-state imaging device of the present invention includes a plurality of microlenses, a plurality of photoelectric conversion units that receive light collected by each of the plurality of microlenses, and charges generated in each of the plurality of photoelectric conversion units. A solid-state imaging device having a signal readout circuit for reading out a corresponding signal, wherein the plurality of microlenses are provided on one side with respect to the layer in which the plurality of photoelectric conversion units exist, and the other side A signal readout circuit is provided, and at least a part of the plurality of microlenses includes a first upward convex lens shape portion, and the center of the first upward convex lens shape portion is decentered with respect to the center of the microlens. In addition, the transmittance is higher than the transmittance of the outermost lens portion of the microlens.
According to this configuration, pupil division can be performed without using a light shielding film. This configuration can be easily manufactured even if the miniaturization is advanced as compared with the configuration of Patent Document 1, and color mixing is less likely to occur, and the phase difference detection accuracy can be improved.

  The imaging device of the present invention includes the solid-state imaging device.

  ADVANTAGE OF THE INVENTION According to this invention, a solid-state image sensor which can perform pupil division | segmentation, preventing a sensitivity fall and generation | occurrence | production of color mixing, and an imaging device provided with the same can be provided.

1 is a schematic plan view showing a schematic configuration of a solid-state imaging device for explaining an embodiment of the present invention. AA line cross-sectional schematic diagram of the solid-state imaging device shown in FIG. BB cross-sectional schematic diagram in the solid-state image sensor shown in FIG. The figure for demonstrating the pupil division | segmentation principle by the pixel part for pupil division | segmentation in the solid-state image sensor shown in FIG. The figure which shows an example of the method of performing pupil division | segmentation without using a light shielding layer in the solid-state image sensor shown in FIG. The figure for demonstrating the effect of the solid-state image sensor shown in FIG. The figure which shows the 1st modification of the solid-state image sensor shown in FIG. The figure which shows the 1st modification of the solid-state image sensor shown in FIG. The figure which shows the 2nd modification of the solid-state image sensor shown in FIG. The figure which shows the 2nd modification of the solid-state image sensor shown in FIG. The figure which shows the 3rd modification of the solid-state image sensor shown in FIG. The figure which shows the 4th modification of the solid-state image sensor shown in FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic plan view showing a schematic configuration of a solid-state imaging device for explaining an embodiment of the present invention. The solid-state imaging device 100 is used by being mounted on an imaging device such as an imaging module of a digital camera, a digital video camera, or a camera-equipped mobile phone. The solid-state imaging device 100 illustrated in FIG. 1 includes a plurality of pixel portions arranged in a two-dimensional manner (in the example of FIG. 1, a square lattice shape) in a row direction X and a column direction Y orthogonal thereto. The plurality of pixel portions include a normal pixel portion 10, a pupil division pixel portion 11, and a pupil division pixel portion 12.

  The pupil division pixel unit 11 forms a pair together with the pupil division pixel unit 12 arranged close to the pupil division (adjacent to the lower right in the example of FIG. 1), and pupil division constituting this pair The pixel unit 11 and the pupil division pixel unit 12 receive light beams that pass through different pupil regions of the photographing lens of the imaging device in which the solid-state imaging device 100 is mounted.

  The normal pixel unit 10 is a pixel unit that does not have a pupil division function.

  2 is a schematic cross-sectional view taken along the line AA in the solid-state imaging device 100 shown in FIG. 3 is a schematic cross-sectional view taken along the line BB in the solid-state imaging device 100 illustrated in FIG.

  In the solid-state imaging device 100, an insulating layer 25 is formed on a support substrate 26, a silicon substrate S as a semiconductor substrate is formed on the insulating layer 25, a color filter layer is formed above the silicon substrate S, and the color filter layer is formed. In this configuration, a microlens layer is formed.

  In the silicon substrate S, a photodiode (PD) 21 is formed as a photoelectric conversion unit separated for each pixel unit by the element isolation layer 23.

  In the silicon substrate S and the insulating layer 25, a signal readout circuit 22 that reads out a signal corresponding to the electric charge generated in the PD 21 of the pixel unit is formed for each pixel unit. The signal readout circuit 22 is composed of a CMOS circuit.

  As the signal readout circuit 22, a floating diffusion for accumulating charges generated in the PD 21 in the silicon substrate S, a semiconductor element layer of a transistor for reading out a signal corresponding to the potential of the floating diffusion, and resetting the potential, etc. In the insulating layer 25, a conductive material layer such as a gate electrode of the transistor and a wiring connected to the transistor is formed.

  A color filter 20 is formed above each PD 21 via an insulating layer (not shown), and a partition wall 24 is formed between the plurality of color filters 20 to prevent color mixing. The plurality of color filters 20 constitute the color filter layer described above. The arrangement of the plurality of color filters 20 is, for example, a Bayer arrangement, and the color filters 20 included in the pupil division pixel units 11 and 12 transmit, for example, green light.

  A microlens 10 a is formed on the color filter 20 of the normal pixel unit 10. The microlens 10a condenses light on the PD 21 below the microlens 10a.

  On the color filter 20 of the pupil division pixel unit 11, a micro lens 11a having the same outer shape as the micro lens 10a is formed. The microlens 11a includes an upward convex lens shape portion 11b, and condenses light on the PD 21 below the upward convex lens shape portion 11b and a portion excluding the upward convex lens shape portion 11b.

  The upward convex lens shape portion 11b has a higher refractive index than the outermost lens portion of the microlens 11a (the portion excluding the upward convex lens shape portion 11b), and has a higher light transmittance than the lens portion. The center in plan view is decentered to the left in the row direction X with respect to the center in plan view of the microlens 11a.

  More specifically, the upward convex lens-shaped portion 11b is provided eccentrically to a position where the end portion contacts the outer peripheral end portion of the microlens 11a.

  On the color filter 20 of the pupil division pixel unit 12, a micro lens 12a having the same outer shape as the micro lens 10a is formed. The microlens 12a includes an upward convex lens shape portion 12b having the same outer shape as the upward convex lens shape portion 11b, and condenses light on the PD 21 below the upward convex lens shape portion 12b and a portion other than the upward convex lens shape portion 12b.

  The upward convex lens shape portion 12b has a higher refractive index than the outermost lens portion of the microlens 12a (the portion excluding the upward convex lens shape portion 12b), has a higher light transmittance than the lens portion, and The center in plan view is decentered to the right in the row direction X with respect to the center in plan view of the microlens 12a.

  More specifically, the upward convex lens shape portion 12b is provided eccentrically to a position where the end portion contacts the outer peripheral end portion of the microlens 12a.

  Thus, in the solid-state imaging device 100, the microlens layer including the microlenses 10a, 11a, and 12a is formed above the surface (front surface) of the silicon substrate S on the light incident side, and what is the light incident side of the silicon substrate S? This is a so-called back-illuminated type imaging device in which a signal readout circuit 22 is formed on the opposite surface (back surface).

  In the solid-state imaging device 100 having such a configuration, light incident on the microlens 10 is incident on the color filter 20 below the microlens 10. Further, a part of the light incident on the microlens 11a passes through the upward convex lens shape portion 11b and enters the color filter 20, and the rest enters the color filter 20 without entering the upward convex lens shape portion 11b. . Further, a part of the light incident on the microlens 12a passes through the upward convex lens shape portion 12b and enters the color filter 20, and the rest enters the color filter 20 without entering the upward convex lens shape portion 12b. . The light that has passed through each color filter 20 enters the PD 21 below, and is converted into electric charge. The converted electric charge is converted into a signal by the signal reading circuit 22 and read out.

  FIG. 4 is a diagram for explaining the principle of pupil division of the pupil division pixel units 11 and 12 in the solid-state imaging device 100 shown in FIG.

  As shown in FIG. 4A, in the pupil division pixel unit 11, a light ray R1 incident on the microlens 11a from the right side in the row direction X and a light ray L1 incident on the microlens 11a from the left side in the row direction X. After being refracted by the outermost lens portion of the microlens 11a, the light enters the upward convex lens shape portion 11b, refracts here, and then enters the color filter 20. As shown in FIG. 4B, in the pupil division pixel unit 12, the light beam R1 incident on the microlens 12a from the right side in the row direction X and the microlens 12a incident on the left side in the row direction X. Each of the light rays L1 is refracted by the outermost lens portion of the microlens 12a, then enters the upward convex lens shape portion 12b, refracts here, and then enters the color filter 20.

  As can be seen from FIG. 4A, the light ray R1 travels a longer distance than the light ray L1 in the outermost lens portion of the microlens 11a having low transmittance and reaches the upward convex lens shape portion 11b. For this reason, the amount of light reaching the PD 21 of the pupil division pixel unit 11 is smaller for the light ray R1 than for the light ray L1. In addition, light rays that enter the microlens 11a from the right side in the row direction X include light rays that reach the color filter 20 without being incident on the upper convex lens shape portion 11b. The amount of light is attenuated by the lens portion of the low microlens 11 a and reaches the PD 21. Further, light rays that enter the microlens 11a from the left side in the row direction X include light rays that reach the color filter 20 without entering the upward convex lens shape portion 11b. Such light rays are rays from the right side. Less than As a result, the pupil division pixel unit 11 selectively receives and photoelectrically converts a light beam from a pupil region eccentric to the left side in the row direction X from the center of the pupil of the photographing lens.

  As can be seen from FIG. 4B, the light ray R1 travels a shorter distance than the light ray L1 in the outermost lens portion of the low-transmittance microlens 12a and reaches the upward convex lens shape portion 12b. For this reason, the amount of light reaching the PD 21 of the pupil division pixel unit 12 is greater for the light ray R1 than for the light ray L1. In addition, light rays that enter the microlens 12a from the left side in the row direction X include light rays that reach the color filter 20 without being incident on the upper convex lens shape portion 12b. The amount of light is attenuated by the lens portion of the low microlens 12 a and reaches the PD 21. Further, light rays that enter the microlens 12a from the right side in the row direction X also include light rays that reach the color filter 20 without entering the upward convex lens shape portion 12b. Such light rays are rays from the left side. Less than As a result, the pupil division pixel unit 12 selectively receives and photoelectrically converts a light beam from a pupil region decentered to the right in the row direction X from the pupil center of the photographing lens.

  In the normal pixel unit 10, since both the light rays R1 and L1 reach the PD 21 by the same amount, a light beam from a pupil region that is not substantially decentered from the center of the pupil of the photographing lens is received and photoelectrically converted.

  In the solid-state imaging device 100, pupil division can be performed by the pupil division pixel units 11 and 12 based on such a principle. Since the solid-state imaging device 100 is a back-illuminated type, there is no light shielding layer above the PD 21 as shown in FIGS. For this reason, compared with the case where pupil division is performed by providing a light-shielding layer and decentering the opening of the light-shielding layer, it is possible to prevent sensitivity improvement and prevention of color mixing due to thinning of the solid-state imaging device 100. In addition, since the pupil division is performed by devising a microlens formation method, compared to the structure described in Patent Document 1, it is easy to cope with miniaturization and manufacture is facilitated.

  In the solid-state imaging device 100, as a method of performing pupil division without using a light shielding layer, for example, as shown in FIG. 5, the microlens of the pupil division pixel unit 11 is only the upward convex lens shape unit 11b ( The same applies to the pupil division pixel unit 12). However, in this case, as shown in FIG. 5, the light that has passed through the upward convex lens-shaped portion 11 b may enter the element isolation layer 23, pass through this, and reach the adjacent PD 21. Becomes higher.

  On the other hand, according to the double structure in which the upward convex lens shape portion 11b is built in the microlens 11a, the light can be refracted to the PD21 side by the microlens 11a as shown in FIG. For this reason, light reaching the element isolation layer 23 can be reduced and color mixing can be prevented as compared with the configuration shown in FIG.

  In the case of the configuration shown in FIG. 5, a large gap is generated between the microlens 10a and the upwardly convex lens-shaped portion 12b. According to the configuration shown in FIG.

  Since the normal pixel unit 10 preferably has higher sensitivity, it is preferable that the transmissivity of the microlens 10a be high, and the upward convex lens shape portions 11b and 12b also have lower sensitivity of the pupil division pixel units 11 and 12. In order to avoid this, it is preferable to keep the transmittance high. Therefore, the transmittance of the microlens 10a and the upward convex lens shape portions 11b and 12b is the same, and the transmittance of the outermost lens portion of the microlenses 11a and 12a is lower than that of the microlens 10a and the upward convex lens shape portions 11b and 12b. It is preferable to keep it. Further, the refractive index of the lens portion excluding the upward convex lens shape portion 11b of the microlens 11a and the refractive index of the upward convex lens shape portion 11b may be the same, or the refractive index of the upward convex lens shape portion 11b is lower. May be. By making the refractive index of the upward convex lens-shaped portion 11b relatively high, light from the pupil region decentered to the left can be efficiently guided to the PD 21 and pupil division performance can be improved. Similarly, the refractive index of the lens portion excluding the upward convex lens shape portion 12b of the microlens 12a and the refractive index of the upward convex lens shape portion 12b may be the same, or the refractive index of the upward convex lens shape portion 12b is greater. It may be low. By making the refractive index of the upward convex lens shape part 12b relatively high, light from the pupil region decentered to the right can be efficiently guided to the PD 21 and pupil division performance can be improved.

  In the above description, the color filter 20 of the pupil division pixel units 11 and 12 is assumed to transmit green light. However, the present invention is not limited to this, and a configuration without a color filter, a configuration with a gray filter, and a white filter The structure which provides, the structure which provides an ND filter, etc. may be sufficient.

  Further, in the solid-state imaging device 100, the color filter 20 may be omitted unless color imaging is intended. Further, the solid-state imaging device 100 may be an element dedicated to distance measurement. In this case, all the pixel units included in the solid-state imaging device 100 may be the pupil division pixel units 11 and 12. The color filter 20 may be omitted even when an element dedicated to distance measurement is used.

  The signal readout circuit 22 may be a CCD circuit. In the case of a CCD circuit, a semiconductor element layer such as a charge transfer channel for transferring charges generated in the PD 21 is formed in the silicon substrate S, and an electrode for applying a voltage to the charge transfer channel is formed in the insulating layer 25. Then, a conductive material layer such as a wiring connected to the electrode is formed. In this case, the signal readout circuit 22 is provided not for each pixel unit but for all the pixel units.

  Below, the modification of the solid-state image sensor 100 is demonstrated.

(First modification)
7 and 8 are diagrams showing a first modification of the solid-state imaging device 100 shown in FIG. 1 and corresponding to FIG.

  In the solid-state imaging device 100 shown in FIGS. 7 and 8, the color filter 20 of the pupil division pixel unit 12 is contracted in the row direction X to be formed only below the upward convex lens shape unit 12b, and the color filter 20 is contracted. The light-shielding layer 24a is added to the remaining space generated in step (b). The light shielding layer 24a only needs to be made of a material that can absorb or reflect light, and is made of, for example, a black color filter. 7 and 8, only the pupil division pixel unit 12 is illustrated, but the light division layer 24a is similarly provided for the pupil division pixel unit 11 as well. Note that the color filter 20 of the pupil division pixel portions 11 and 12 may be omitted, and a transparent insulating material may be filled in the omitted portions.

  According to the configuration shown in FIG. 7 and FIG. 8, the light that passes through only the portion excluding the upper convex lens shape portion 12b of the microlens 12a and does not enter the upper convex lens shape portion 12b is directed to the PD 21 by the light shielding layer 24a. It can absorb or reflect. Therefore, the pupil division performance of the pupil division pixel units 11 and 12 can be improved as compared with the cases shown in FIGS. Further, since the light shielding layer 24a also plays a role of decentering the opening of the PD 21, it is possible to realize pupil division to some extent by itself. Therefore, compared with the case where the light shielding layer 24a is not provided, the degree of freedom in designing the size of the upward convex lens shape portion 12b and the transmittance of the portion excluding the upward convex lens shape portion 12b of the microlens 12a can be increased. In addition, since the light shielding layer 24a is formed in the same layer as the color filter 20, the thickness of the solid-state imaging device 100 is not increased, and a decrease in sensitivity and an increase in color mixture can be prevented.

(Second modification)
9 and 10 are diagrams showing a second modification of the solid-state imaging device 100 shown in FIG. 1 and corresponding to FIGS.

  In the solid-state imaging device 100 illustrated in FIG. 9, the size of the upper convex lens shape portion 11b of the pupil division pixel portion 11 is small, and the microlens 11a includes the upper convex lens shape portion 11c including the upper convex lens shape portion 11b. Except for this point, the configuration is the same as that shown in FIG.

  The upward convex lens shape portion 11c has a lower transmittance than the lens portion outside the upward convex lens shape portion 11c of the microlens 11a, and the center in plan view is the row direction X than the center in plan view of the microlens 11a. Eccentric on the left side. In addition, the refractive index of all the lens portions of the microlens 11a is higher as it is on the inner side. That is, the refractive index of the outermost lens portion of the micro lens 11a (the portion outside the upward convex lens shape portion 11c) <the refractive index of the upward convex lens shape portion 11c <the refractive index of the upward convex lens shape portion 11b.

  In the solid-state imaging device 100 shown in FIG. 10, the size of the upper convex lens shape portion 12b of the pupil division pixel portion 12 is small, and the microlens 12a has the upper convex lens shape portion 12c including the upper convex lens shape portion 12b. Except for this point, the configuration is the same as that shown in FIG.

  The upward convex lens shape portion 12c has a lower transmittance than the lens portion outside the upward convex lens shape portion 12c of the microlens 12a, and the center in plan view is the row direction X than the center in plan view of the microlens 12a. Eccentric on the right side. Further, the refractive index of all the lens portions of the microlens 12a is higher as it is on the inner side. That is, the refractive index of the outermost lens portion of the micro lens 12a (the portion outside the upward convex lens shape portion 12c) <the refractive index of the upward convex lens shape portion 12c <the refractive index of the upward convex lens shape portion 12b.

  9 and 10, since the microlenses of the pupil division pixel portions 11 and 12 have a triple structure, the light that has passed through the upper convex lens shape portions 11b and 12b is applied to the silicon substrate S. On the other hand, it becomes easier to move in the vertical direction, and the effect of preventing color mixture can be enhanced. In this configuration, the transmittance of the upper convex lens-shaped portions 11c and 12c is lower than that of the outermost lens portion of the microlenses 11a and 12a. For this reason, in the case of the pupil division pixel unit 11, the light incident from the right side in the row direction X can be strongly attenuated by the outermost lens portion of the microlens 11a and the upper convex lens shape portion 11c. With the dividing pixel unit 12, light incident from the left side in the row direction X can be strongly attenuated by the outermost lens portion of the micro lens 12a and the upward convex lens shape portion 12c, thereby improving pupil division performance. Can be made.

  In FIGS. 9 and 10, the transmittance of the upper convex lens-shaped portions 11c and 12c may be higher than or the same as the outermost lens portion of the microlenses 11a and 12a. Even in this case, it is possible to obtain the effect of preventing color mixing due to the triple structure of the microlens. Further, the refractive indexes of the lens portions of the microlenses 11a and 12a may all be the same, or may be higher as they are on the outer side. By increasing the refractive index to the inner side, the light from the pupil region decentered to the right or left can be efficiently guided to the PD 21 and the pupil division performance can be improved.

  Further, in the microlens 11a (12a), a plurality of upwardly convex lens shape portions containing the upwardly convex lens shape portion 11b (12b) may be provided. In this case, the plurality of upper convex lens-shaped portions provided except for the size are all the same configuration as the upper convex lens-shaped portion 11c (12c) (for example, the center is decentered to the left (right side) with respect to the microlens 11a (12a), The transmittance may be lower than that of the outermost lens portion of the lens 11a (12a).

(Third modification)
FIG. 11 is a diagram showing a third modification of the solid-state imaging device 100 shown in FIG. The solid-state imaging device 200 illustrated in FIG. 11 includes a plurality of pixel units arranged two-dimensionally in the row direction X and the column direction Y. The plurality of pixel portions are composed of only two types of pupil division pixel portions, ie, the pupil division pixel portion 11 and the pupil division pixel portion 12 shown in FIG.

  In FIG. 11, only the microlens 11a and the upward convex lens shape portion 11b included in the pupil division pixel unit 11 are illustrated, and the microlens 12a and the upward convex lens included in the pupil division pixel unit 12 are illustrated. Only the shape part 12b is illustrated.

  The same number of pupil division pixel units 11 and pupil division pixel units 12 are present and arranged in a square lattice at the same pitch. The arrangement of the color filters 20 in the pupil division pixel unit 11 is a Bayer arrangement as a whole, and the arrangement of the color filters 20 in the pupil division pixel unit 12 is also a Bayer arrangement as a whole. A pupil division pixel unit 12 having a color filter of the same color as that of the pupil division pixel unit 11 is arranged at a position where the pupil division pixel unit 11 arranged in a square lattice shape is shifted diagonally 45 ° to the lower right. The pupil division pixel unit 11 and the pupil division pixel unit 12 that is adjacent to the pupil division pixel unit 11 obliquely in the lower right direction form a pair.

  In the solid-state imaging device 200, the captured image signals obtained from all the pupil division pixel units 11 and the captured image signals obtained from all the pupil division pixel units 12 are obtained when the same subject is viewed from different directions. It will be a thing. Therefore, there is a parallax between the image based on the captured image signal obtained from all the pupil division pixel units 11 and the image based on the captured image signal obtained from all the pupil division pixel units 12. A stereoscopic image can be reproduced by two images.

  When the configurations shown in FIGS. 9 and 10 are adopted as the pupil division pixel units 11 and 12, the parallax can be particularly increased.

  Note that in the solid-state imaging device 200, one set of images with parallax can be generated by two types of pixel units, ie, the pupil division pixel unit 11 and the pupil division pixel unit 12, but for example, an upward convex lens shape unit 11b or the like It is also possible to provide a solid-state imaging device having three or more types of pupil division pixel portions by providing another pupil division pixel portion in which the center of the upward convex lens shape portion 12b is decentered in the column direction Y. In this case, by combining the images obtained from each of the three or more types of pupil division pixel units, it is possible to reproduce two or more stereoscopic images with different viewpoints for the same subject.

(Fourth modification)
FIG. 12 is a diagram illustrating a fourth modification of the solid-state imaging device 100 illustrated in FIG. 1, and corresponds to FIG. In the description of FIGS. 1 to 11, the solid-state imaging device is a back-illuminated type, but the present invention can also be applied to a photoelectric conversion layer stacked-type solid-state imaging device, and a configuration example in this case is illustrated. 12. 12, the configuration above the color filter 20 is the same as that in FIG. 3, and therefore the configuration below the color filter 20 will be described below. The configuration of the pupil division pixel unit 11 is the same as that of FIG. 12 except that the configuration above the color filter 20 is the same as that shown in FIG.

  The solid-state imaging device shown in FIG. 12 has a configuration in which a photoelectric conversion layer 33 is formed above the silicon substrate 35 and a color filter layer is formed above the photoelectric conversion layer 33.

  On the insulating layer 39 on the silicon substrate 35, pixel electrodes 34 divided for each pixel portion are formed. In the insulating layer 39, a contact portion 37 that is electrically connected to the pixel electrode 34 is formed for each pixel portion.

  A signal readout circuit 32 is formed for each pixel portion in the silicon substrate 35 and the insulating layer 39, and this signal readout circuit 32 is connected to the pixel electrode 34 via a contact portion 37.

  The signal readout circuit 32 includes a charge accumulation unit that accumulates the charges collected by the pixel electrode 34 and a CMOS circuit that reads out a signal corresponding to the charges accumulated in the charge accumulation unit.

  As the signal readout circuit 32, a charge storage unit and a semiconductor element layer of a transistor for reading a signal corresponding to the charge of the charge storage unit and resetting the charge are formed in the silicon substrate 35, and an insulating layer In the layer 39, a conductive material layer such as a gate electrode of the transistor and a wiring connected to the transistor is formed.

  When the signal readout circuit 32 is a CCD circuit, a charge storage portion and a semiconductor element layer such as a charge transfer channel for transferring charges generated in the charge storage portion are formed in the silicon substrate 35, and in the insulating layer 39 A conductive material layer such as an electrode for applying a voltage to the charge transfer channel and a wiring connected to the electrode is formed. In the case of a CCD circuit, the signal readout circuit 32 is provided not for each pixel unit but for all the pixel units.

  On the pixel electrode 34 provided for each pixel portion, a photoelectric conversion layer 33 common to all the pixel portions is formed so as to cover it. The photoelectric conversion layer 33 is a layer made of a photoelectric conversion material that receives light and generates a charge corresponding to the light.

  On the photoelectric conversion layer 33, a transparent counter electrode 31 common to all the pixel portions is formed. A transparent insulating layer 38 is formed on the counter electrode 31, and a color filter layer is formed thereon.

  Thus, even with a photoelectric conversion layer stacked solid-state imaging device, pupil division can be performed without using a light shielding layer.

  The contents described so far can be appropriately combined within a range where no contradiction occurs. For example, the first modified example and the second modified example are combined, the first and second modified examples are combined with the third modified example, the fourth modified example and the first to third modified examples are combined. Can be combined.

  As described above, the following items are disclosed in this specification.

  The disclosed solid-state imaging device includes a plurality of microlenses, a plurality of photoelectric conversion units that receive light collected by each of the plurality of microlenses, and a charge generated in each of the plurality of photoelectric conversion units. A solid-state imaging device having a signal readout circuit for reading out a corresponding signal, wherein the plurality of microlenses are provided on one side with respect to the layer in which the plurality of photoelectric conversion units exist, and the other side A signal readout circuit is provided, and at least a part of the plurality of microlenses includes a first upward convex lens shape portion, and the center of the first upward convex lens shape portion is decentered with respect to the center of the microlens. In addition, the transmittance is higher than the transmittance of the outermost lens portion of the microlens.

  In the disclosed solid-state imaging device, at least a part of the plurality of microlenses incorporates at least one second upward convex lens shape portion including the first upward convex lens shape portion, and the second upward convex lens shape The center of the portion is decentered in the same direction as the center decentering direction of the first upward convex lens-shaped portion with respect to the microlens with respect to the center of the microlens.

  In the disclosed solid-state imaging device, the transmittance of the second upward convex lens-shaped portion included in the microlens is lower than the transmittance of the lens portion located on the outermost side of the microlens.

  In the disclosed solid-state imaging device, the refractive indexes of at least some of the plurality of microlenses are different in all lens portions.

  In the disclosed solid-state imaging device, the refractive index of at least a part of the plurality of microlenses is larger as the lens portion is on the inner side.

  In the disclosed solid-state imaging device, the microlens provided with the first upward convex lens-shaped portion is a microlens that is a part of the plurality of microlenses, and a micro that excludes the part of the plurality of microlenses. A color filter is provided between the lens and the photoelectric conversion unit, and the photoelectric of the light collected by the micro lens is formed in the same layer as the color filter between the partial micro lens and the photoelectric conversion unit. The light-shielding layer which restrict | limits the incident amount to a conversion part is provided, The said light-shielding layer is an opening formed in the downward direction of said 1st upward convex lens-shaped part with which said one part microlens is equipped.

  In the disclosed solid-state imaging device, the microlens including the first upward convex lens shape portion is all the microlenses of the plurality of microlenses, and all the first upward convex lens shape portion and the photoelectric conversion portion A color filter is provided between the microlens and the photoelectric conversion unit, and a light shielding layer is formed on a portion excluding the color filter.

  In the disclosed solid-state imaging device, the signal readout circuit is formed on a semiconductor substrate, and the photoelectric conversion unit is stacked above the semiconductor substrate.

  In the disclosed solid-state imaging device, the photoelectric conversion unit is formed in a semiconductor substrate, the signal readout circuit is formed on the front surface side of the semiconductor substrate, and the plurality of microlenses are formed on the back surface side of the semiconductor substrate. It is what.

  The disclosed imaging device includes the solid-state imaging device.

DESCRIPTION OF SYMBOLS 100 Solid-state image sensor 10 Normal pixel part 11 and 12 Pixel part 10a, 11a, 12a for pupil division | segmentation Micro lens 11b, 12b Up convex lens shape part 20 Color filter 21 PD
22 Signal readout circuit S Silicon substrate

Claims (10)

A plurality of microlenses, a plurality of photoelectric conversion units that receive light collected by each of the plurality of microlenses, and a signal readout circuit that reads signals according to the charges generated in each of the plurality of photoelectric conversion units A solid-state imaging device comprising:
The plurality of microlenses are provided on one side with respect to the layer in which the plurality of photoelectric conversion units exist, and the signal readout circuit is provided on the other side,
At least a part of the plurality of microlenses includes a first upward convex lens shape portion,
The first upward convex lens-shaped portion is a solid whose center is decentered with respect to the center of the microlens and whose transmittance is higher than the transmittance of the lens portion on the outermost side of the microlens Image sensor. The solid-state imaging device according to claim 1,
At least a part of the plurality of microlenses incorporates at least one second upward convex lens shape portion including the first upward convex lens shape portion,
The second upward convex lens-shaped part is a solid-state imaging device whose center is decentered with respect to the center of the microlens in the same direction as the eccentric direction of the center of the first upward convex lens-shaped part with respect to the microlens. The solid-state imaging device according to claim 2,
A solid-state imaging device in which the transmittance of the second upward convex lens-shaped portion included in the microlens is lower than the transmittance of a lens portion located on the outermost side of the microlens. The solid-state image sensor according to any one of claims 1 to 3,
A solid-state imaging device in which a refractive index of at least some of the plurality of microlenses is different in all lens portions. The solid-state imaging device according to claim 4,
A solid-state imaging device in which a refractive index of at least a part of the plurality of microlenses is increased toward an inner lens portion. The solid-state imaging device according to any one of claims 1 to 5,
The microlens having the first upward convex lens shape portion is a microlens that is part of the plurality of microlenses,
A color filter is provided between the microlens excluding the part of the plurality of microlenses and the photoelectric conversion unit,
In the same layer as the color filter between the part of the microlenses and the photoelectric conversion unit, a light shielding layer for limiting the amount of light collected by the microlens to the photoelectric conversion unit is provided,
The light shielding layer is a solid-state imaging device in which an opening is formed below the first upward convex lens-shaped portion provided in the partial microlens. The solid-state imaging device according to any one of claims 1 to 5,
The microlens provided with the first upward convex lens shape portion is all microlenses of the plurality of microlenses,
A color filter is provided between all the first upward convex lens-shaped portions and the photoelectric conversion portions,
A solid-state imaging device in which a light shielding layer is formed in a portion excluding the color filter among all the microlenses and the photoelectric conversion unit. The solid-state imaging device according to any one of claims 1 to 7,
The signal readout circuit is formed on a semiconductor substrate;
A solid-state imaging device in which the photoelectric conversion unit is stacked above the semiconductor substrate. The solid-state imaging device according to any one of claims 1 to 7,
The photoelectric conversion part is formed in a semiconductor substrate,
The signal readout circuit is formed on the surface side of the semiconductor substrate;
A solid-state imaging device in which the plurality of microlenses are formed on the back side of the semiconductor substrate.   An imaging device provided with the solid-state image sensor of any one of Claims 1-7.

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