Photoelectric conversion device and apparatus

Abstract

To improve tone reproducibility in a photoelectric conversion device in which a plurality of photoelectric conversion elements are arranged to share a microlens.SOLUTION: Each pixel of a photoelectric conversion device has a first photoelectric conversion element PEC1 and a second photoelectric conversion element PEC2 that share a microlens 104, and the first photoelectric conversion element includes a first region R1 of a first conductivity type arranged between a predetermined depth of a substrate having a first surface and a second surface and the second surface, and a second region R2 of a first conductivity type arranged between the predetermined depth and the first surface and electrically connected to the first region via a first connection part CN1. The second photoelectric conversion element includes a third region R3 of a first conductivity type arranged between the second surface and the predetermined depth, and a fourth region R4 of a first conductivity type arranged between the predetermined depth and the first surface and electrically connected to the third region via a second connection part CN2. The pixel has a charge leak part 208 that is arranged at an intersection part to electrically connect the first photoelectric conversion element and the second photoelectric conversion element.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a photoelectric conversion device and an apparatus. [Background technology]

[0002] There is a photoelectric conversion device in which multiple photoelectric conversion elements are arranged in each pixel for image plane phase-difference autofocus (AF). Patent Document 1 describes a photoelectric conversion device including pixels each having a first photoelectric conversion element and a second photoelectric conversion element that share a microlens. The photoelectric conversion device described in Patent Document 1 has a first layer and a second layer stacked on top of each other in a substrate. The first photoelectric conversion element has a first impurity region arranged in the first layer and a second impurity region arranged in the second layer. The second photoelectric conversion element has a third impurity region arranged in the first layer and a fourth impurity region arranged in the second layer. The first layer has a first isolation region between the first impurity region and the third impurity region, and the second layer has a second isolation region between the second impurity region and the fourth impurity region. The multiple pixels include pixels in which the first isolation region and the second isolation region extend in different directions from each other in a plan view relative to the first surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-27686 Summary of the Invention [Problem to be solved by the invention]

[0004] In a configuration in which multiple photoelectric conversion elements are arranged to share a microlens, the total number of saturated charges is smaller than in a configuration in which one photoelectric conversion element is arranged per microlens, which can result in reduced gradation reproducibility.

[0005] An object of the present invention is to provide an advantageous technique for improving tone reproducibility in a photoelectric conversion device in which a plurality of photoelectric conversion elements are arranged so as to share a microlens. [Means for solving the problem]

[0006] One aspect of the present invention relates to a photoelectric conversion device having a substrate on which a plurality of pixels are arranged, wherein each pixel has a first photoelectric conversion element and a second photoelectric conversion element that share a microlens, the substrate has a first surface and a second surface disposed between the first surface and the microlens, the first photoelectric conversion element includes a first region of a first conductivity type disposed between a predetermined depth of the substrate and the second surface, and a second region of the first conductivity type disposed between the predetermined depth and the first surface and electrically connected to the first region via a first connection portion, The second photoelectric conversion element includes a third region of the first conductivity type arranged between the second surface and the predetermined depth, and a fourth region of the first conductivity type arranged between the predetermined depth and the first surface and electrically connected to the third region via a second connection portion, regions of the second conductivity type are arranged between the first region and the second region and between the third region and the fourth region, a first isolation region is arranged so as to extend between the first region and the third region, and a second isolation region is arranged so as to extend between the second region and the fourth region, the multiple pixels include a first pixel having an intersection portion where the first isolation region and the second isolation region intersect in an orthogonal projection onto the first surface, and the first pixel has a charge leakage portion arranged at the intersection portion so as to electrically connect the first photoelectric conversion element and the second photoelectric conversion element. [Effects of the Invention]

[0007] According to the present invention, an advantageous technique is provided for improving the tone reproducibility in a photoelectric conversion device in which a plurality of photoelectric conversion elements are arranged so as to share a microlens. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing the configuration of a photoelectric conversion device according to a first embodiment. [Figure 2] FIG. 2 is a plan view showing an example of the configuration of two types of pixels. [Figure 3] 1A to 1C are diagrams showing three configuration examples of a pixel array of a photoelectric conversion device. [Figure 4] FIG. 2 is a diagram showing an example of the configuration of a first type pixel. [Figure 5] FIG. 10 is a diagram showing an example of the configuration of a second type of pixel. [Figure 6] 4A to 4C are diagrams illustrating a method for forming a first isolation region and an implantation concentration profile. [Figure 7] 3A and 3B are diagrams for explaining examples of the configuration of first-type pixels and second-type pixels. [Figure 8] 3A and 3B are diagrams for explaining examples of the configuration of first-type pixels and second-type pixels. [Figure 9] FIG. 10 is a diagram showing an example of the arrangement of a pixel of a photoelectric conversion device according to a second embodiment. [Figure 10] FIG. 2 is a diagram illustrating an example of the configuration of a device. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention. Although the embodiments describe multiple features, not all of these features are necessarily essential to the invention, and multiple features may be combined in any desired manner. Furthermore, in the accompanying drawings, the same reference numerals are used to designate identical or similar components, and redundant explanations will be omitted.

[0010] In the following embodiments, an image capturing device will be mainly described as an example of a photoelectric conversion device. However, the embodiments are not limited to image capturing devices and can be applied to other examples of photoelectric conversion devices. For example, a distance measuring device (a device for measuring distance using focus detection or TOF (Time Of Flight)) or a photometric device (a device for measuring the amount of incident light) can be used.

[0011] A photoelectric conversion device 101 according to a first embodiment will be described with reference to FIGS. 1 to 8. The photoelectric conversion device 101 may be configured, for example, as an imaging device that captures an optical image and outputs a digital or analog image signal. Alternatively, the photoelectric conversion device 101 may be configured as a processing device that processes information obtained from the optical image and outputs the results. The following description will be given assuming that the signal charges are electrons, but the same applies when the signal charges are holes, except that the conductivity types of the impurities are reversed. In addition, the following description will be given assuming that the first conductivity type is N-type and the second conductivity type is P-type. However, when the signal charges are holes, the first conductivity type is P-type and the second conductivity type is N-type.

[0012] As illustrated in FIG. 1, a photoelectric conversion device 101 has a plurality of pixels 102. The pixels 102 may be arranged, for example, in a plurality of rows and a plurality of columns to form a pixel array, but this is not limitative. FIGS. 2(a) and 2(b) are schematic plan views showing the configurations of two types of pixels 102. FIGS. 2(a) and 2(b) also show a schematic view of a first surface of a substrate on which the pixels 102 are arranged. The first surface is typically recognized as the front surface (front face) and may be understood as the surface on which transistors are arranged or the surface that undergoes a lithography process during manufacturing. The second surface, which is the surface opposite the first surface, is typically recognized as the back surface, and a microlens 104 may be arranged on the second surface side. A photoelectric conversion device in which a microlens is arranged on the second surface (back surface) side is called a back-illuminated type.

[0013] Light incident on the photoelectric conversion device 101 passes through a microlens 104 and enters a first photoelectric conversion element PEC1 and a second photoelectric conversion element PEC2 formed on a substrate. The first photoelectric conversion element PEC1 and the second photoelectric conversion element PEC2 share one microlens 104. The pixel 102 includes a floating diffusion 106 (hereinafter also referred to as FD). The pixel 102 also includes a first transfer gate TX1 for transferring charges from the first photoelectric conversion element PEC1 to the FD106, and a second transfer gate TX2 for transferring charges from the second photoelectric conversion element PEC2 to the FD106.

[0014] The first photoelectric conversion element PEC1 has a first region R1 of a first conductivity type arranged on the first surface side of the substrate (between a predetermined depth in the substrate and the first surface) and a second region R2 of the first conductivity type arranged on the second surface side of the substrate (in other words, between a predetermined depth in the substrate and the second surface). The first region R1 and the second region R2 are electrically connected by a first connection part CN1. The second photoelectric conversion element PEC2 has a third region R3 of a first conductivity type arranged on the first surface side of the substrate (between a predetermined depth in the substrate and the first surface) and a fourth region R4 of a first conductivity type arranged on the second surface side of the substrate (between a predetermined depth in the substrate and the second surface). The third region R3 and the fourth region R4 are electrically connected by a second connection part CN2. In FIGS. 2(a) and 2(b), the second region R2 and the fourth region R4 on the first surface side are indicated by solid lines, and the first region R1 and the third region R3 on the second surface side are indicated by dotted lines.

[0015] Charges (electrons) generated by photoelectric conversion in the first region R1 on the second surface (rear surface) side move to the second region R2 through the first connection part CN1, and are transferred to FD106 when an active level potential is supplied to the first transfer gate TX1. The first region R1 constitutes the main photoelectric conversion part, and the second region R2 constitutes the charge transport part. Similarly, charges (electrons) generated by photoelectric conversion in the third region R3 on the second surface (rear surface) side move to the fourth region R4 through the second connection part CN2, and are transferred to FD106 when an active level potential is supplied to the second transfer gate TX2. The third region R3 constitutes the main photoelectric conversion part, and the fourth region R4 constitutes the charge transport part.

[0016] For image-plane phase-detection AF, a pixel configuration in which the first and second photoelectric conversion elements share a single microlens may be employed. In such a pixel configuration, the subject pattern for which defocus amount detection (i.e., focusing) is easier varies depending on the direction in which the first and second photoelectric conversion elements are arranged. For example, arranging the first and second photoelectric conversion elements horizontally provides high sensitivity for detecting the defocus amount of a subject with vertical stripe contrast, but does not provide high sensitivity for detecting the defocus amount of a subject with horizontal stripe contrast. Arranging the first and second photoelectric conversion elements in a certain direction means arranging the first and second photoelectric conversion elements so that their respective centers of gravity are offset in that direction. Furthermore, the direction (arrangement direction) in which the first and second photoelectric conversion elements, each having a main photoelectric conversion unit and a charge transport unit, are arranged refers to the direction in which the main photoelectric conversion units are arranged. In order to facilitate detection of the defocus amount for a greater number of subject patterns, it is sufficient to arrange a plurality of types of pixels in which the photoelectric conversion elements (main photoelectric conversion portions) are arranged in different directions.

[0017] Although not shown in Figure 1, the photoelectric conversion device 101 may include, for example, a vertical scanning circuit that selects rows of a pixel array, a readout circuit that reads out signals from pixels in the pixel array, and a horizontal scanning circuit that sequentially outputs signals read out by the readout circuit.

[0018] FIG. 2(a) shows a pixel (second pixel) in which the first region R1 and the third region R3, which are main photoelectric conversion units, are arranged in the horizontal direction 111. This arrangement is advantageous for detecting the defocus amount of an object having vertical stripe contrast. FIG. 2(b) shows a pixel (first pixel) in which the first region R1 and the third region R3, which are main photoelectric conversion units, are arranged in the vertical direction 112. This arrangement is advantageous for detecting the defocus amount of an object having horizontal stripe contrast. Note that although the terms horizontal and vertical are used here for convenience of explanation, these are subjective concepts. More objectively, a pixel in which the main photoelectric conversion units are arranged in a certain direction is advantageous for detecting the defocus amount of an object pattern in which the light intensity varies in that direction.

[0019] The arrangement direction of the second region R2 and the fourth region R4, which are charge transport regions, is preferably the same for the pixel in Figure 2(a) and the pixel in Figure 2(b). This configuration is advantageous because it allows the positions of the charge transport region, transfer gate, and FD within a pixel to be the same for multiple pixels, regardless of the arrangement direction (arrangement direction) of the main photoelectric conversion region. This is useful for reducing manufacturing variations between pixels and reducing characteristic differences between pixels.

[0020] 3(a), (b), and (c) schematically show configuration examples of a pixel array of a photoelectric conversion device 101. The configuration example of FIG. 3(a) shows an example in which all of the pixels 102 of the photoelectric conversion device 101 are pixels in which main photoelectric conversion units are arranged in a horizontal direction 111. The configuration example of FIG. 3(b) shows an example in which all of the pixels 102 of the photoelectric conversion device 101 are pixels in which main photoelectric conversion units are arranged in a vertical direction 112. The configuration example of FIG. 3(c) shows an example in which the photoelectric conversion device 101 has a plurality of pixels 102 in which main photoelectric conversion units are arranged in the horizontal direction 111 and a plurality of pixels 102 in which main photoelectric conversion units are arranged in the vertical direction 112.

[0021] The photoelectric conversion device 101 of FIG. 3(a) is advantageous for performing high-speed, high-precision AF on a vertically striped subject pattern, and the photoelectric conversion device 101 of FIG. 3(b) is advantageous for performing high-speed, high-precision AF on a horizontally striped subject pattern. The photoelectric conversion device 101 of FIG. 3(c) is advantageous for performing high-speed, high-precision AF on both vertically striped and horizontally striped subject patterns. The photoelectric conversion device 101 of FIG. 3(c) has two types of pixels in the direction in which the main photoelectric conversion units are arranged, but may have more types of pixels. The other type of pixel to be added is a pixel in which the main photoelectric conversion units are arranged in a diagonal direction.

[0022] 4(a) to 4(e) show a more detailed example of the configuration of the first-type pixel 102 (second pixel) shown in FIG. 2(a). FIG. 4(a) is a schematic plan view showing the configuration of the first-type pixel 102. FIG. 4(b) is a schematic cross-sectional view taken along line A-A' in FIG. 4(a). FIG. 4(c) is a schematic cross-sectional view taken along line C-C' in FIG. 4(a). FIG. 4(d) is a schematic cross-sectional view taken along line B-B' in FIG. 4(a). FIG. 4(e) is a schematic cross-sectional view taken along line D-D' in FIG. 4(a).

[0023] The substrate SS on which the pixels 102 are arranged has a first surface S1 and a second surface S2. The second surface S2 is disposed between the first surface S1 and the microlens 104. In other words, the microlens 104 is disposed on the second surface S2 (back surface) side of the substrate SS. The substrate SS may be, for example, a single-crystal silicon substrate.

[0024] The first photoelectric conversion element PEC1 includes a first region R1 of a first conductivity type disposed between a predetermined depth DD of the substrate SS and the second surface S2, and a second region R2 of the first conductivity type disposed between the predetermined depth DD and the first surface S1. The predetermined depth DD can be determined according to required specifications. The second region R2 is electrically connected to the first region R1 via a first connection portion CN1. The second photoelectric conversion element PEC2 includes a third region R3 of the first conductivity type disposed between the second surface S2 and the predetermined depth DD, and a fourth region R4 disposed between the predetermined depth DD and the first surface S1. The fourth region R4 is electrically connected to the third region R3 via a second connection portion CN2.

[0025] A second conductivity type region 203 is arranged between the first region R1 and the second region R2 and between the third region R3 and the fourth region R4. The first connection portion CN1 and the second connection portion CN2 may be arranged to pass through the second conductivity type region 203. The first connection portion CN1 and the second connection portion CN2 may be first conductivity type regions.

[0026] The first isolation region I1 is disposed to extend between the first region R1 and the third region R3, and the second isolation region I2 is disposed to extend between the second region R2 and the fourth region R4. Here, the first isolation region I1 may have an elongated shape, and the longitudinal direction of the first isolation region I1 may be perpendicular to the direction in which the first region R1 and the third region R3 are arranged side by side. The second isolation region I2 may have an elongated shape, and the longitudinal direction of the second isolation region I2 may be perpendicular to the direction in which the second region R2 and the fourth region R4 are arranged side by side. In the first-type pixels 102, the extending direction of the first isolation region I1 and the extending direction of the second isolation region I2 are parallel to each other. For convenience, the first-type pixels 102 may be referred to as parallel pixels.

[0027] Light passing through the first region of the pupil plane of the imaging lens is incident on the microlens 104 of each pixel 102 of the photoelectric conversion device 101, passes through the microlens 104, and enters the first region R1. As a result, charge pairs, i.e., holes and electrons, are generated by photoelectric conversion in the first region R1. Of these, the electrons, which are signal charges, move along the potential gradient from the first region R1 to the second region R2 through the first connection CN1 and are accumulated in the second region R2. Similarly, light passing through the second region of the pupil plane of the imaging lens is incident on the microlens 104 of each pixel 102 of the photoelectric conversion device 101, passes through the microlens 104, and enters the third region R3. As a result, charge pairs, i.e., holes and electrons, are generated by photoelectric conversion in the third region R3. Of these, the electrons, which are signal charges, move along the potential gradient from the third region R3 to the fourth region R4 through the second connection CN2 and are accumulated in the fourth region R4.

[0028] A second conductivity type isolation region 204 may be arranged between adjacent pixels 102 to suppress charge crosstalk therebetween. Furthermore, a second conductivity type region 206 may be provided between the first surface S1 and the second region R2 and between the first surface S1 and the fourth region R4 to suppress dark current. Similarly, a second conductivity type region 205 may be provided between the second surface S2 and the first region R1 and between the second surface S2 and the third region R3 to suppress dark current.

[0029] The first photoelectric conversion element PEC1 and the second photoelectric conversion element PEC2 may be electrically isolated by the first isolation region I1 and the second isolation region I2 described above. The first isolation region I1 may include a region of the second conductivity type. Alternatively, the first isolation region I1 may include an insulator. Alternatively, the first isolation region I1 may include a region of the second conductivity type and an insulator. The second isolation region I2 may include a region of the second conductivity type. Alternatively, the second isolation region I2 may include an insulator. Alternatively, the second isolation region I2 may include a region of the second conductivity type and an insulator.

[0030] For phase difference detection for image-plane phase-difference detection AF, the output (referred to as A) of the first photoelectric conversion element PEC1 and the output (referred to as B) of the second photoelectric conversion element PEC2 of each pixel 102 may be used. The photoelectric conversion device 101 may (a) output A and B, (b) output A and A+B, or (c) output B and A+B. In the case of (b), B can be obtained by calculating the difference between (A+B) and A. In the case of (c), A can be obtained by calculating the difference between (A+B) and B. A+B is used to generate an image signal (image data).

[0031] When capturing an image of a highly luminous subject, signal charges may be generated that exceed the amount of charge that the first photoelectric conversion element PEC1 (or the second photoelectric conversion element PEC2) can store. In such a case, the linearity of the output value of the pixel 102 relative to the luminance of incident light can be improved by leaking charges from the first photoelectric conversion element PEC1 (or the second photoelectric conversion element PEC2) to the second photoelectric conversion element PEC2 (or the first photoelectric conversion element PEC1). Therefore, the pixel 102 may have a charge leak unit 208 arranged to electrically connect the first photoelectric conversion element PEC1 and the second photoelectric conversion element PEC2. However, the charge leak unit 208 is configured to prevent free movement of charges between the first photoelectric conversion element PEC1 and the second photoelectric conversion element PEC2. Specifically, the charge leak unit 208 forms a potential barrier to some extent against the movement of charges between the first photoelectric conversion element PEC1 and the second photoelectric conversion element PEC2. However, if the potential barrier is too high, excess charge generated in the first photoelectric conversion element PEC1 or the second photoelectric conversion element PEC2 may flow into the FD 106 or other pixels 102. This may result in a decrease in the color reproducibility of the captured image. Therefore, the height of the potential barrier can be adjusted to meet target specifications.

[0032] The charge leakage portion 208 may be arranged to cross the second isolation region I2. From another perspective, the charge leakage portion 208 may be arranged between the second region R2 and the fourth region R4. The charge leakage portion 208 may include a region of the first conductivity type. The photoelectric conversion device 101 may be formed so that the amount (absolute amount) of the second conductivity type impurity in the charge leakage portion 208 is less than the amount (absolute amount) of the second conductivity type impurity in the second isolation region I2. For example, in the step of implanting the second conductivity type impurity into the substrate SS to form the second isolation region I2, the implantation of the second conductivity type impurity into the region that will become the charge leakage portion 208 may be limited by a mask.

[0033] In one aspect, the charge leakage portion 208 may be located between the first surface S1 and a predetermined depth DD. In another aspect, the shortest distance between the first surface S1 and the charge leakage portion 208 may be smaller than the shortest distance between the second surface S2 and the charge leakage portion 208. As illustrated in Figures 4(a) to 4(e), in an orthogonal projection (or a plan view) onto the first surface S1, the center (or vertex) of the microlens 104 may be located within the region of the charge leakage portion 208.

[0034] The configuration in which the charge leak portion 208 is disposed between the second region R2 and the fourth region R4 is advantageous for obtaining a structure in which excess charge leaks between the first photoelectric conversion element PEC1 and the second photoelectric conversion element PEC2 only when capturing an image of a high-brightness subject. With this configuration, the first photoelectric conversion element PEC1 and the second photoelectric conversion element PEC2 are separated from each other to realize the phase difference detection function, while the linearity of the output value of each pixel 102 relative to the brightness of incident light can be improved.

[0035] 5(a) to 5(e) show a more detailed example of the configuration of the second-type pixel 102 (first pixel) shown in FIG. 2(a). FIG. 5(a) is a schematic plan view showing the configuration of the second-type pixel 102. FIG. 5(b) is a schematic cross-sectional view taken along line A-A' in FIG. 5(a). FIG. 5(c) is a schematic cross-sectional view taken along line C-C' in FIG. 5(a). FIG. 5(d) is a schematic cross-sectional view taken along line B-B' in FIG. 5(a). FIG. 5(e) is a schematic cross-sectional view taken along line D-D' in FIG. 5(a).

[0036] The following describes the differences between the second-type pixels 102 and the first-type pixels 102. Matters not mentioned in relation to the second-type pixels 102 will be explained with reference to the first-type pixels 102. The second-type pixels 102 have an intersection CP where the first isolation region I1 and the second isolation region I2 intersect in an orthogonal projection (plan view) onto the first surface S1. The second-type pixels 102 may be conveniently referred to as intersection pixels. The second-type pixels 102 have a charge leak portion 208 disposed at the intersection CP so as to electrically connect the first photoelectric conversion element PEC1 and the second photoelectric conversion element PEC2. In one example, the second-type pixels 102 may be disposed such that the direction in which the first isolation region I1 extends (the horizontal direction in FIG. 5(a)) and the direction in which the second isolation region I2 extends (the vertical direction in FIG. 5(a)) are orthogonal to each other. The charge leak portion 208 may be disposed so as to cross the second isolation region I2. The charge leak portion 208 may be disposed between the second region R2 and the fourth region R4.

[0037] The charge leakage portion 208 may include a region of the first conductivity type. The photoelectric conversion device 101 may be formed so that the amount (absolute amount) of impurities of the second conductivity type in the charge leakage portion 208 is less than the amount (absolute amount) of impurities of the second conductivity type in the second isolation region I2. For example, in the step of implanting impurities of the second conductivity type into the substrate SS to form the second isolation region I2, the implantation of the impurities of the second conductivity type into the region that will become the charge leakage portion 208 may be limited by a mask. The photoelectric conversion device 101 typically includes a plurality of second-type pixels 102, and the relative positions of the charge leakage portions 208 in the second-type pixels 102 may be the same in the plurality of second-type pixels 102.

[0038] In one aspect, the charge leakage portion 208 may be located between the first surface S1 and a predetermined depth DD. In another aspect, the shortest distance between the first surface S1 and the charge leakage portion 208 may be smaller than the shortest distance between the second surface S2 and the charge leakage portion 208. As illustrated in Figures 5(a) to 5(e), in an orthogonal projection (or a plan view) onto the first surface S1, the center (or vertex) of the microlens 104 may be located within the region of the charge leakage portion 208.

[0039] The first-type pixels 102 illustrated in Figures 4(a) to 4(e) and the second-type pixels 102 illustrated in Figures 5(a) to 5(e) differ in the direction in which the first regions R1 and the second regions R2 extend. From another perspective, the first-type pixels 102 illustrated in Figures 4(a) to 4(e) and the second-type pixels 102 illustrated in Figures 5(a) to 5(e) differ in the direction in which the first regions R1 and the second regions R2 extend (from another perspective, the direction in which the first isolation region I1 extends). On the other hand, the first-type pixels 102 illustrated in Figures 4(a) to 4(e) and the second-type pixels 102 illustrated in Figures 5(a) to 5(e) have the same direction in which the third regions R3 and the fourth regions R4 extend. From another perspective, the directions in which the third region R3 and the fourth region R4 extend (from another perspective, the directions in which the second isolation region I2 extends) are the same in the first type of pixel 102 illustrated in Figures 4(a) to (e) and the second type of pixel 102 illustrated in Figures 5(a) to (e).

[0040] In the first type of pixels 102 illustrated in Figures 4(a) to 4(e), the direction in which the first regions R1 and the second regions R2 are arranged is the horizontal direction, so high sensitivity can be obtained for detecting the defocus amount of an object with vertical stripe contrast. On the other hand, in the second type of pixels 102 illustrated in Figures 5(a) to 5(e), the direction in which the first regions R1 and the second regions R2 are arranged is the vertical direction, so high sensitivity can be obtained for detecting the defocus amount of an object with horizontal stripe contrast.

[0041] The relative positions of the first connection portions CN1 within the pixels 102 are preferably the same in the first-type pixels 102 and the second-type pixels 102. Furthermore, the relative positions of the second connection portions CN2 within the pixels 102 are preferably the same in the first-type pixels 102 and the second-type pixels 102. This is advantageous for reducing manufacturing variations between the first-type pixels 102 and the second-type pixels 102 and reducing differences in characteristics between the first-type pixels 102 and the second-type pixels 102. In an orthogonal projection (or a plan view) onto the first surface S1, a charge leakage portion 208 may be arranged between the first connection portion CN1 and the second connection portion CN2.

[0042] 6 illustrates a method for forming the first isolation region I1 and its implantation concentration profile (impurity profile). As described above, the first isolation region I1 is provided to separate the first region R1 of the first photoelectric conversion element PEC1 from the third region R3 of the second photoelectric conversion element PEC2. The first isolation region I1 can be formed by forming a resist pattern 301 on the first surface S1 of the substrate SS and implanting second conductivity type (P-type) impurities into the substrate SS through openings 302 in the resist pattern 301. The second conductivity type impurities implanted into the substrate SS through the openings 302 in the resist pattern 301 reach deep positions in the substrate SS, thereby forming the first isolation region I1. On the other hand, the second conductivity type impurities implanted into the resist pattern 301 are ideally completely absorbed by the resist pattern 301 and do not reach the substrate SS. However, some of the second-conductivity-type impurities implanted near the opening 302 in the resist pattern 301 may be redirected by colliding with the material constituting the resist pattern 301, and may fly out from the side of the opening 302 and reach the substrate SS. Because these impurities consume energy as they pass through the resist pattern 301, they may be implanted at a shallow position in the substrate SS. Therefore, as shown in the graph on the right side of FIG. 6 , the concentration of the second-conductivity-type impurities implanted into the semiconductor substrate SS may be higher the closer to the first surface S1 of the substrate SS. This may affect the potential profile within the substrate SS. Specifically, the potential is lower in the region overlapping with the first isolation region I1 in the orthogonal projection (plan view) onto the first surface S1, and this may act as a potential barrier against signal charges (electrons).

[0043] FIG. 7(a) shows a plan view of a first-type pixel 102, and FIG. 7(b) shows a plan view of a second-type pixel 102. The left side of FIG. 7(c) illustrates a potential profile of the first-type pixel 102 along the Y direction in FIG. 7(a) at the depth of the charge leakage portion 208. The right side of FIG. 7(c) illustrates a potential profile of the second-type pixel 102 along the Y direction in FIG. 7(b) at the depth of the charge leakage portion 208. In the two potential profiles in FIG. 7(c), the vertical axis represents potential, and the horizontal axis represents position in the Y direction. By providing the charge leakage portion 208, the potential barrier against signal charge (electrons) is lowered.

[0044] The first isolation region I1 extends in different directions between the first-type pixels 102 and the second-type pixels 102. Therefore, the potential profile on the first surface S1 side of the substrate SS (for example, the region between the first surface S1 and a predetermined depth DD) may differ between the first-type pixels 102 and the second-type pixels 102. Therefore, it is preferable to arrange the charge leak portion 208 at the intersection CP of the second-type pixels 102, and to make the relative position of the intersection CP (charge leak portion 208) in the second-type pixels 102 the same as the relative position of the charge leak portion 208 in the first-type pixels 102. This makes it possible to make the first-conductivity-type impurity concentration (potential from another perspective) in the charge leak portion 208 of the first-type pixels 102 the same as the first-conductivity-type impurity concentration (potential from another perspective) in the charge leak portion 208 of the second-type pixels 102.

[0045] FIG. 8(a) shows a plan view of a first-type pixel 102, and FIG. 8(b) shows a plan view of a second-type pixel 102. The left side of FIG. 8(c) illustrates a potential profile of the first-type pixel 102 along line A-A' in FIG. 8(a) at the depth of the charge leakage portion 208. The right side of FIG. 8(c) illustrates a potential profile of the second-type pixel 102 along line C-C' in FIG. 8(b) at the depth of the charge leakage portion 208. The left side of FIG. 8(d) illustrates a potential profile of the first-type pixel 102 along line B-B' in FIG. 8(a) at the depth of the charge leakage portion 208. The right side of FIG. 8(d) illustrates a potential profile of the second-type pixel 102 along line D-D' in FIG. 8(b) at the depth of the charge leakage portion 208. In the four potential profiles in FIGS. 8(c) and 8(d), the vertical axis represents the potential, and the horizontal axis represents the position in the Y direction.

[0046] The charge generated by photoelectric conversion and accumulated in the second region R2 leaks to the fourth region R4 when the potential of the second region R2 reaches the potential of the charge leak portion 208. Similarly, the charge generated by photoelectric conversion and accumulated in the fourth region R4 leaks to the second region R2 when the potential of the fourth region R4 reaches the potential of the charge leak portion 208.

[0047] Comparing the potential profile along line B-B' with the potential profile along line D-D' reveals a difference in potential in second isolation region I2 due to the second conductivity type impurities implanted into the region between first isolation region I1 and first surface S1. However, comparing the potential profile along line A-A' with the potential profile along line C-C' reveals that the potentials in charge leak portion 208 are the same.

[0048] A photoelectric conversion device 101 according to a second embodiment will now be described with reference to FIG. 9. The photoelectric conversion device 101 according to the second embodiment is a modified example of the photoelectric conversion device 101 according to the first embodiment, and matters not described here may follow the first embodiment. FIG. 9(a) shows a plan view of a first configuration example of a second-type pixel 102, and FIG. 9(b) shows a plan view of a second configuration example of a second-type pixel 102. In the first and second configuration examples, the second isolation region I2 extends in an oblique direction. In other words, the angle between the extension direction of the first isolation region I1 and the extension direction of the second isolation region I2 is greater than 0 degrees and less than 90 degrees. Alternatively, the angle between the extension direction of the first isolation region I1 and the extension direction of the second isolation region I2 is greater than 90 degrees and less than 180 degrees. The plurality of pixels of the photoelectric conversion device 101 may include pixels 102 of the first configuration example and pixels 102 of the second configuration example. The plurality of pixels of the photoelectric conversion device 101 may further include first-type pixels 102 and / or second-type pixels 102 of the first embodiment.

[0049] Such a configuration is advantageous for detecting the defocus amount of a pattern in which the light intensity changes in an oblique direction, in addition to a vertical stripe pattern and a horizontal stripe pattern.

[0050] Hereinafter, a device 1000 incorporating a photoelectric conversion device 101 will be described with reference to Fig. 10. The device 1000 can include at least one of an optical device 1040, a control device 1050, a processing device 1060, a display device 1070, a storage device 1080, and a mechanical device 1090. The optical device 1040 is, for example, a lens, a shutter, or a mirror. The control device 1050 controls the semiconductor chip 210. The control device 1050 is, for example, a semiconductor device such as an ASIC.

[0051] The processing device 1060 processes the signal output from the photoelectric conversion device 101. The processing device 1060 is a semiconductor device such as a CPU or ASIC for configuring an analog front end (AFE) or a digital front end (DFE). The display device 1070 is an EL display device or a liquid crystal display device that displays information (images) obtained by the semiconductor chip 210. The storage device 1080 is a magnetic device or a semiconductor device that stores information (images) obtained by the semiconductor chip 210. The storage device 1080 is a volatile memory such as an SRAM or a DRAM, or a non-volatile memory such as a flash memory or a hard disk drive.

[0052] The mechanical device 1090 has a moving part or a propulsion part such as a motor or an engine. In the device 1000, the signal output from the semiconductor chip 210 is displayed on the display device 1070, or transmitted to the outside by a communication device (not shown) provided in the device 1000. For this purpose, the device 1000 may further include a storage device 1080 and a processing device 1060 in addition to the storage circuit and arithmetic circuit provided in the semiconductor chip 210. The mechanical device 1090 may be controlled based on the signal output from the semiconductor chip 210.

[0053] The device 1000 is also suitable for electronic devices such as information terminals with a photographing function (e.g., smartphones and wearable devices) and cameras (e.g., interchangeable lens cameras, compact cameras, video cameras, and surveillance cameras). The mechanical device 1090 in the camera can drive components of the optical device 1040 for zooming, focusing, and shutter operation. Alternatively, the mechanical device 1090 in the camera can move the semiconductor chip 210 for vibration isolation.

[0054] Furthermore, the device 1000 may be transportation equipment such as a vehicle, a ship, or an aircraft. The mechanical device 1090 in the transportation equipment may be used as a moving device. The device 1000 as transportation equipment is suitable for transporting semiconductor chips 210 or for assisting and / or automating driving (piloting) using a photographing function. The processing device 1060 for assisting and / or automating driving (piloting) can perform processing for operating the mechanical device 1090 as a moving device based on information obtained by the semiconductor chip 210. Alternatively, the device 1000 may be a medical device such as an endoscope, a measuring device such as a distance measuring sensor, an analytical device such as an electron microscope, an office machine such as a copier, or an industrial device such as a robot. (Item 1) A photoelectric conversion device having a substrate on which a plurality of pixels are arranged, each pixel having a first photoelectric conversion element and a second photoelectric conversion element that share a microlens, the substrate having a first surface and a second surface arranged between the first surface and the microlens, the first photoelectric conversion element includes a first region of a first conductivity type arranged between a predetermined depth of the substrate and the second surface, and a second region of the first conductivity type arranged between the predetermined depth and the first surface and electrically connected to the first region via a first connection portion; the second photoelectric conversion element includes a third region of the first conductivity type arranged between the second surface and the predetermined depth, and a fourth region of the first conductivity type arranged between the predetermined depth and the first surface and electrically connected to the third region via a second connection portion; a second conductivity type region is disposed between the first region and the second region and between the third region and the fourth region; a first isolation region is arranged to extend between the first region and the third region, and a second isolation region is arranged to extend between the second region and the fourth region; the plurality of pixels includes a first pixel having an intersection where the first isolation region and the second isolation region intersect in an orthogonal projection onto the first plane; the first pixel has a charge leak portion disposed at the intersection so as to electrically connect the first photoelectric conversion element and the second photoelectric conversion element; A photoelectric conversion device characterized by: (Item 2) the charge leakage portion is arranged to cross the second isolation region; 2. The photoelectric conversion device according to item 1, (Item 3) the charge leakage portion is disposed between the second region and the fourth region; 3. The photoelectric conversion device according to item 1 or 2, (Item 4) the charge leakage portion includes the first conductivity type region; 4. The photoelectric conversion device according to any one of items 1 to 3, characterized in that: (Item 5) the second isolation region includes a region of the second conductivity type; 5. The photoelectric conversion device according to any one of items 1 to 4, characterized in that: (Item 6) the amount of the second conductivity type impurity in the charge leakage portion is less than the amount of the second conductivity type impurity in the second isolation region; 6. The photoelectric conversion device according to item 5, (Item 7) the charge leakage portion is located between the first surface and the predetermined depth; 7. The photoelectric conversion device according to any one of items 1 to 6, wherein: (Item 8) the shortest distance between the first surface and the charge leak portion is shorter than the shortest distance between the second surface and the charge leak portion; 7. The photoelectric conversion device according to any one of items 1 to 6, wherein: (Item 9) In the orthogonal projection, the center of the microlens is located within the region of the charge leakage portion. 9. The photoelectric conversion device according to any one of items 1 to 8, characterized in that: (Item 10) In the orthogonal projection, the charge leak portion is disposed between the first connection portion and the second connection portion. 10. The photoelectric conversion device according to any one of items 1 to 9, characterized in that: (Item 11) the second isolation region includes an insulator; 11. The photoelectric conversion device according to any one of items 1 to 10, characterized in that: (Item 12) a direction in which the first isolation region extends and a direction in which the second isolation region extends are perpendicular to each other; 12. The photoelectric conversion device according to any one of items 1 to 11, characterized in that: (Item 13) the plurality of pixels include a second pixel in which the extending direction of the first isolation region and the extending direction of the second isolation region are parallel to each other; 13. The photoelectric conversion device according to any one of items 1 to 12, characterized in that: (Item 14) the plurality of pixels includes a plurality of the first pixels, the relative positions of the charge leakage portions in the first pixels are the same in the plurality of first pixels; 14. The photoelectric conversion device according to any one of items 1 to 13, (Item 15) Each pixel further includes a floating diffusion, a first transfer gate for transferring charges of the first photoelectric conversion element to the floating diffusion, and a second transfer gate for transferring charges of the second photoelectric conversion element to the floating diffusion. 15. The photoelectric conversion device according to any one of items 1 to 14, wherein: (Item 16) The photoelectric conversion device according to any one of items 1 to 15, a processing device that processes a signal output from the photoelectric conversion device; An apparatus characterized by comprising:

[0055] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0056] 101: photoelectric conversion device, 102: pixel, PEC1: first photoelectric conversion element, PEC2: second photoelectric conversion element, SS: substrate, S1: first surface, S2: second surface, R1: first region, R2: second region, R3: third region, R4: fourth region, I1: first isolation region, I2: second isolation region

Claims

1. A photoelectric conversion device having a substrate on which a plurality of pixels are arranged, each pixel having a first photoelectric conversion element and a second photoelectric conversion element that share a microlens, the substrate having a first surface and a second surface arranged between the first surface and the microlens, the first photoelectric conversion element includes a first region of a first conductivity type arranged between a predetermined depth of the substrate and the second surface, and a second region of the first conductivity type arranged between the predetermined depth and the first surface and electrically connected to the first region via a first connection portion; the second photoelectric conversion element includes a third region of the first conductivity type arranged between the second surface and the predetermined depth, and a fourth region of the first conductivity type arranged between the predetermined depth and the first surface and electrically connected to the third region via a second connection portion; a second conductivity type region is disposed between the first region and the second region and between the third region and the fourth region; a first isolation region is arranged to extend between the first region and the third region, and a second isolation region is arranged to extend between the second region and the fourth region; the plurality of pixels includes a first pixel having an intersection portion where the first isolation region and the second isolation region intersect in an orthogonal projection onto the first plane; the first pixel has a charge leak portion disposed at the intersection so as to electrically connect the first photoelectric conversion element and the second photoelectric conversion element; A photoelectric conversion device characterized by:

2. the charge leakage portion is arranged to cross the second isolation region; 2. The photoelectric conversion device according to claim 1.

3. the charge leakage portion is disposed between the second region and the fourth region; 2. The photoelectric conversion device according to claim 1.

4. the charge leakage portion includes a region of the first conductivity type; 2. The photoelectric conversion device according to claim 1.

5. the second isolation region includes a region of the second conductivity type; 2. The photoelectric conversion device according to claim 1.

6. the amount of the second conductivity type impurity in the charge leakage portion is less than the amount of the second conductivity type impurity in the second isolation region; 6. The photoelectric conversion device according to claim 5.

7. the charge leakage portion is located between the first surface and the predetermined depth; 2. The photoelectric conversion device according to claim 1.

8. the shortest distance between the first surface and the charge leak portion is shorter than the shortest distance between the second surface and the charge leak portion; 2. The photoelectric conversion device according to claim 1.

9. In the orthogonal projection, the center of the microlens is located within the region of the charge leakage portion.

2. The photoelectric conversion device according to claim 1.

10. In the orthogonal projection, the charge leakage portion is disposed between the first connection portion and the second connection portion.

2. The photoelectric conversion device according to claim 1.

11. the second isolation region includes an insulator.

2. The photoelectric conversion device according to claim 1.

12. a direction in which the first isolation region extends and a direction in which the second isolation region extends are perpendicular to each other; 2. The photoelectric conversion device according to claim 1.

13. the plurality of pixels include a second pixel in which the extending direction of the first isolation region and the extending direction of the second isolation region are parallel to each other; 2. The photoelectric conversion device according to claim 1.

14. the plurality of pixels includes a plurality of the first pixels, the relative positions of the charge leakage portions in the first pixels are the same in the plurality of first pixels; 2. The photoelectric conversion device according to claim 1.

15. Each pixel further includes a floating diffusion, a first transfer gate for transferring charges of the first photoelectric conversion element to the floating diffusion, and a second transfer gate for transferring charges of the second photoelectric conversion element to the floating diffusion.

15. The photoelectric conversion device according to claim 1.

16. The photoelectric conversion device according to any one of claims 1 to 14, a processing device that processes a signal output from the photoelectric conversion device; An apparatus characterized by comprising:

Images