JP2020098853A - Photoelectric conversion element, and manufacturing method of photoelectric conversion element - Google Patents

Abstract

To suppress a potential barrier in a pixel receiving near infrared light, in a photoelectric conversion element receiving visible light and near infrared light.SOLUTION: A photoelectric conversion element comprises: a first charge storage part that is a first conductivity type semiconductor region; a second charge storage part that is a first conductivity type semiconductor region; an isolation region that is formed under the first charge storage part and that is composed of a second conductivity type semiconductor region which has a conductivity type being different from the first conductivity type; and a non-isolation region that is formed under the second charge storage part and that is composed of a semiconductor region which has lower potential for electric charges than the isolation region. The isolation region and the non-isolation region are provided to have a same highness, the non-isolation region is surrounded by the isolation region in a plan view, and a size of an opening of the isolation region surrounding the non-isolation region is larger than a size of a pixel having the second charge storage part in plan view.SELECTED DRAWING: Figure 2

Description

The present invention relates to a photoelectric conversion element and a manufacturing method thereof.

There is an image sensor (photoelectric conversion element) in which visible pixels (RGB pixels) that receive visible light and near infrared pixels (Z pixels; IR pixels) that receive near infrared light are mixed. For example, in Non-Patent Document 1, a potential barrier (deep separation region) is provided below a photodiode of a visible pixel in order to prevent signal charges in the near infrared region photoelectrically converted in the deep portion of the substrate from entering the visible pixel. An image sensor is disclosed.

Wonjoo Kim, Wang Yibing, Ilia Ovsiannikov, SeungHoon Lee, Yoondong Park, Chilhee Chung, Eric Fossum1, "A 1.5Mpixel RGBZ CMOS Image Sensor for Simultaneous Color and Range Image Capture", Solid-State Circuits Conference Digest of Technical Papers (ISSCC ), SESSION22/IMAGE SENSORS/22.7, 2012 IEEE International, February 2012, p. 392-394

However, in the image sensor (photoelectric conversion element) disclosed in Non-Patent Document 1, for example, when impurities contained in the potential barrier diffuse into the surrounding region, the potential for the signal charge in the near infrared region in the near infrared pixel is increased. Barriers can be created.

Therefore, an object of the present invention is to suppress a potential barrier in a pixel that receives near infrared light in a photoelectric conversion element that receives visible light and near infrared light.

The first aspect of the present invention is
A first charge storage portion that is a semiconductor region of a first conductivity type;
A second charge storage portion which is the first conductivity type semiconductor region;
An isolation region formed under the first charge storage unit, the isolation region including a second conductivity type semiconductor region having a conductivity type different from the first conductivity type;
A non-separation region formed of a semiconductor region formed below the second charge storage unit and having a lower potential for electric charges than the separation region;
Have
The separation region and the non-separation region are provided at the same height,
In a plan view, the non-separation area is surrounded by the separation area,
In plan view, the size of the opening of the separation region surrounding the non-separation region is larger than the size of the pixel having the second charge storage unit.
It is a photoelectric conversion element characterized by the above.

The second aspect of the present invention is
By implanting an impurity of the second conductivity type different from the first conductivity type into the semiconductor substrate of the first conductivity type, a non-separation region that is a region where the impurities of the second conductivity type are not implanted in a plan view. A separation area forming step of forming a separation area surrounding the
A first charge storage part for storing charges is formed on the separation region,
A step of forming a second charge storage part for storing charges on the non-separation region,
Have
In the separation area forming step,
In plan view, the opening of the separation region surrounding the non-separation region is formed larger than the size of the pixel having the second charge storage unit formed in the storage unit formation step.
A method for manufacturing a photoelectric conversion element, which is characterized by the above.

In a photoelectric conversion element that receives visible light and near infrared light, it is possible to suppress a potential barrier in a pixel that receives near infrared light.

The top view of the photoelectric conversion element which concerns on Example 1. Sectional drawing of the photoelectric conversion element which concerns on Example 1. FIG. 3 is a diagram showing a potential in the photoelectric conversion element according to Example 1. Sectional drawing of the other photoelectric conversion element which concerns on Example 1. Flow of manufacturing method of photoelectric conversion element according to Example 1 FIG. 3 is a diagram illustrating a method of manufacturing the photoelectric conversion element according to the first embodiment. FIG. 3 is a diagram illustrating a method of manufacturing the photoelectric conversion element according to the first embodiment. FIG. 3 is a diagram illustrating a method of manufacturing the photoelectric conversion element according to the first embodiment. Plan view and cross-sectional view of a photoelectric conversion element according to Example 2 Plan and sectional view of the photoelectric conversion element according to Example 3 FIG. 6 is a diagram illustrating a configuration example of an imaging system according to a fourth embodiment. FIG. 10 is a diagram illustrating a configuration example of an imaging system and a moving body according to a fifth embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited to the following embodiments (examples).

<Example 1>
The photoelectric conversion element (solid-state imaging device) according to the first embodiment of the present invention will be described below. In this embodiment, by providing a deep isolation region having an opening having a size (width) larger than the size (width) of the pixel receiving near-infrared light, the pixel for the signal charge (electron) is provided. A photoelectric conversion element that suppresses the potential barrier of will be described. The near-infrared light (light in the near-infrared region) in this embodiment is light including light having a wavelength length of 0.70 to 1.4 μm.

[Configuration of photoelectric conversion element]
The structure of the photoelectric conversion element according to this embodiment is described with reference to FIGS. 1A, 1B, and 2A. 2A is a cross-sectional view of the photoelectric conversion element according to the present embodiment, and FIG. 1A and FIG. 1B are plan views of the photoelectric conversion element (a plan view; Is a diagram of a cross section perpendicular to. Here, FIG. 1A shows a plan view in the BB′ cross section of FIG. 2A, and FIG. 1B shows a plan view in the CC′ cross section of FIG. 2A. ing. Further, FIG. 2A is a cross-sectional view taken along the line AA′ of FIG.

The photoelectric conversion element includes a pixel 100 and a pixel 100 ′, and includes a charge storage unit 101, a charge storage unit 101 ′, a pixel separation region 102, a deep separation region 103, a non-separation region 104, and a photoelectric conversion region 105.

Note that, hereinafter, the side where the charge storage portion 101 ′ is formed with respect to the non-separation region 104 is referred to as “upper part”. Further, in the case of defining the “upper part” in this way, it can be said that light such as visible light or near-infrared light enters from the upper part of the photoelectric conversion element. The direction opposite to the "upper part" is called "lower part" or "deep part", and the "depth" and "height" indicate the position in the vertical direction. Note that in this embodiment, a pixel is an area surrounded by a dotted line in FIG. 2B, and the photoelectric conversion element in FIG. 2A is based on the center of the pixel separation area 102. It is an area divided in the vertical direction.

The pixel 100 is a pixel that receives visible light. The pixel 100' is a pixel that receives near infrared light (light in the near infrared region). The pixel 100 includes a charge storage unit 101 that stores signal charges obtained by photoelectrically converting visible light. The pixel 100 ′ has a charge storage unit 101 ′ that stores signal charges obtained by photoelectrically converting near infrared light. Here, the charge storage units 101 and 101 ′ are N-type regions (N-type semiconductor regions; N-type impurity regions) containing a large amount of N-type impurities. Further, each of the pixels 100 and 100 ′ has a pixel separation region 102 that surrounds the charge accumulation portions 101 and 101 ′ and separates adjacent pixels (adjacent charge accumulation portions). In this embodiment, the pixel isolation region 102 is a P-type region (P-type semiconductor region; P-type impurity region) that contains a large amount of P-type impurities to separate adjacent pixels.

In the present embodiment, a filter (not shown) for selecting the transmitted light is formed above the pixel 100 that receives visible light and the pixel 100' that receives near infrared light. This filter selects (determines) the light transmitted to each pixel according to the wavelength of the light. Here, the filter formed in the pixel 100 transmits visible light, and the filter formed in the pixel 100' transmits near infrared light. That is, it can be said that the filter determines whether the charges accumulated in the charge accumulating units 101 and 101 ′ are photoelectrically converted from visible light or photoelectrically converted from near-infrared light. Further, since the filter (color filter) formed in the pixel 100 has an uneven shape, a flattening film having no filter function is further formed on the filter. Since the depth of penetration of near-infrared light is deeper than that of visible light, and light is received (photoelectric conversion) at a deep portion, a filter is formed in the pixel 100′ when a planarization film is formed. You don't have to.

In this embodiment, the pixels 100 are formed adjacent to each other so as to surround the pixel 100' that receives near infrared light. Further, for simplification, in this embodiment, as shown in FIG. 1A, a case is shown in which nine pixels are formed two-dimensionally in the vertical and horizontal directions, but the pixels are arrayed one-dimensionally. Alternatively, more than 9 pixels may be formed.

The deep isolation region 103 is a P-type region (P-type semiconductor region) formed in a region below the charge storage unit 101 and the pixel isolation region 102 and electrically connected to the pixel isolation region 102. Further, since the deep isolation region 103 contains a large amount of P-type impurities, the impurity concentration is higher than that of the non-isolation region 104, and the potential for the signal charge generated by the photoelectric conversion region 105 is higher than that of the non-isolation region 104. Thereby, the deep isolation region 103 functions as a potential barrier between the charge storage unit 101 and the photoelectric conversion region 105 with respect to the signal charges generated by the photoelectric conversion region 105. Note that the potential barrier in this embodiment prevents the charge of interest from flowing into the region. Here, the deep isolation region 103 is formed by implanting P-type impurities into the semiconductor substrate.

The non-separation region 104 is a region in which the deep separation region 103 is not formed in order to capture the signal charge of near-infrared light photoelectrically converted by the photoelectric conversion region 105 into the charge storage unit 101′. Here, the non-isolation region 104 is formed at the same depth (height) as the deep isolation region 103.

The photoelectric conversion region 105 is formed in a region below the non-separation region 104 of the pixel 100 ′ and photoelectrically converts near infrared light. The signal charge generated by the photoelectric conversion of the near infrared light is stored in the charge storage unit 101'. In addition, depending on the depth of the deep isolation region 103, the photoelectric conversion region 105 can also perform photoelectric conversion for visible light.

With such a configuration, the pixel 100 can receive visible light and the pixel 100' can receive near infrared light. Further, the signal charge of near-infrared light photoelectrically converted in the photoelectric conversion region 105 can be accumulated (collected) in the charge accumulation unit 101' of the pixel 100'. In the above description, for example, the non-separation region 104 is a P-type semiconductor region, but the non-separation region 104 may have a lower potential for signal charges than the deep separation region 103. Therefore, the non-isolation region 104 may be formed of an N-type semiconductor region.

[Relationship between Pixel and Opening Size of Deep Separation Area]
The relationship between the size of the pixel 100′ and the size of the opening of the deep isolation region 103 in this embodiment will be described below.

Here, the size (width) of the pixel 100' is W1, which is the distance between the centers of the pixel separation regions 102, as shown in FIG. Further, as shown in FIG. 1B, the size of the opening of the deep isolation region 103 is W2 which is the size of the non-isolation region 104.

In Non-Patent Document 1, the deep isolation region is provided as the potential barrier, but in Non-Patent Document 1, the opening size W2 of the deep isolation region is considered to be the same as the pixel size W1. Here, FIG. 3A shows the potential for the signal charge in the DD′ cross section of FIG. 2A when the aperture size W2≦pixel size W1. In this case, since the opening size W2 is smaller than or equal to the pixel size W1, the impurities injected into the deep isolation region 103 diffuse into the non-isolation region 104, so that the potential barrier as shown in FIG. Occurs at 104.

Therefore, in this embodiment, in order to suppress the influence of the diffusion of impurities, the opening size W2 of the deep isolation region 103 is made larger than the pixel size W1, so that the non-isolation region 104 is formed as shown in FIG. Lower the potential for signal charge. As a result, the signal charges photoelectrically converted in the region below the deep isolation region 103 can be accumulated (collected) in the charge accumulation unit 101'. Here, making the opening size W2 of the deep isolation region 103 larger than the pixel size W1 specifically means that the pixel 100′ is included in the non-isolation region 104 when the photoelectric conversion element is seen through from above. It can be said that it is to be done.

In the present embodiment, the photoelectric conversion element in which the deep isolation region 103 surrounds the non-isolation region 104 and the size W2 of the opening of the deep isolation region 103>the pixel size W1 of the pixel 100' has been described. However, not limited to this, the pixel separation region 102 may surround a part of the non-separation region 104 as shown in FIG. In this case, in addition to the relationship between the opening size W2 and the pixel size W1 described above, a photoelectric conversion element in which the size W3 of the opening surrounding the non-separation region 104 by the pixel separation region 102 is larger than the pixel size W1 is used. Good to have.

Although the pixel separation region 102 has been described as a separation region that performs pixel separation by containing a large amount of P-type impurities, the present invention is not limited to this. For example, the pixel isolation region 102 may be a trench 106 (groove) as shown in FIG. 4B, which is formed by using a technique such as deep trench isolation (Deep Trench Isolation). Here, in the present embodiment, the trench 106 is filled with an insulating material to separate adjacent pixels.

[Method for manufacturing photoelectric conversion element]
Next, a method for manufacturing the photoelectric conversion element according to the first embodiment will be described with reference to FIGS. FIG. 5 is a flowchart showing the method for manufacturing the photoelectric conversion element in this embodiment. 6A, FIG. 7A, and FIG. 8A are cross-sectional views of the photoelectric conversion element corresponding to each step (each step) of the manufacturing method. 6B, FIG. 7B are plan views (views in plan view) taken along the line AA′ of FIGS. 6A, 7A, and 8A. ) And FIG. 8(B). At the start of the flowchart shown in FIG. 5, a semiconductor substrate such as an N-type semiconductor substrate is prepared. Note that the non-separation region 104 is a region other than the region in which the deep separation region 103 is formed in the depth region where the deep separation region 103 is formed by the processing of the flowchart.

First, in S1001 (isolation region forming step), as shown in FIGS. 6A and 6B, the deep isolation region 103 is formed in the semiconductor substrate. Specifically, for example, as shown in FIG. 6A, a resist pattern 107 that is a photoresist pattern is formed on the N-type semiconductor substrate. Then, a P-type impurity is implanted (ion-implanted) into a predetermined position from the upper portion (front surface) of the N-type semiconductor substrate, so that the deep isolation region 103 is formed inside the N-type semiconductor substrate. Then, the resist pattern 107 is removed. As a result, the deep separation region 103 is formed for the pixel 100 that receives visible light, but the deep separation region 103 is not formed for the pixel 100' that receives near infrared light. Here, the deep isolation region 103 is formed so that the size W2 of the opening of the deep isolation region 103 is larger than the size W1 of the pixel 100'.

In S1002 (pixel separation forming step), the pixel separation region 102 as shown in FIGS. 7A and 7B is formed. Specifically, the resist pattern 108 is formed on the N-type semiconductor substrate, and the P-type impurity is implanted at a position above the deep isolation region 103 to form the pixel isolation region 102. Then, the resist pattern 108 is removed. The pixel isolation region 102 can also be formed by implanting P-type impurities at a plurality of depths. Here, by using different resist patterns, "the size W1 of the pixel 100'<the size W3 of the opening in which the pixel separation region 102 surrounds the non-separation region 104" is established as shown in FIG. It is also possible to form such a pixel separation region 102.

As the pixel isolation region 102, the trench 106 may be formed using a technique such as deep trench element isolation as described with reference to FIG.

In S1003 (accumulation portion formation step), charge accumulation portions 101 and 101' as shown in FIGS. 8A and 8B are formed. Specifically, the resist pattern 109 is formed on the N-type semiconductor substrate, and N-type impurities are implanted at a position above the deep isolation region 103 to form the charge storage units 101 and 101 ′. After that, the resist pattern 109 is removed. At this time, the charge accumulating portions 101 and 101 ′ are formed at the positions surrounded by the pixel separation region 102. In order to reduce the noise component from the surface of the N-type semiconductor substrate, a buried photodiode (not shown) may be formed by injecting P-type impurities into the surface of the charge storage unit 101.

The P-type impurity is implanted into the N-type semiconductor substrate to form the pixel isolation region 102 and the deep isolation region 103, and the N-type impurity is implanted to charge the charge accumulation portions 101 and 101′. Was formed, but not limited to this. Specifically, by implanting an N-type impurity into the P-type semiconductor substrate, a pixel isolation region 102 and a deep isolation region 103 are formed, and by implanting a P-type impurity, the charge storage unit 101 is formed. , 101' have been formed, but not limited to this. That is, even when the conductivity types of the semiconductors such as “P-type” and “N-type” in Example 1 are interchanged, the same effect as described above can be obtained.

In the present embodiment, the pixel 100 receives visible light and the pixel 100' receives near infrared light, but the invention is not limited to this. Specifically, if the light received by the pixel 100' is one that penetrates into the inside (having a longer penetration depth) than the light received by the pixel 100, the pixels 100 and 100' receive any light. It may be The light received by the pixels 100 and 100 ′ can be determined by the type of filter and the depth of the photoelectric conversion region 105 described above.

According to this example, in the photoelectric conversion element, the deep isolation region having the opening having a size (width) larger than the size (width) of the pixel receiving the near infrared light is formed. As a result, the influence of diffusion of impurities from the deep isolation region can be suppressed, so that the potential barrier for signal charges (electrons) in the pixel that receives near infrared light can be suppressed.

<Example 2>
The photoelectric conversion element according to the present embodiment will be described with reference to FIG. 9A is a plan view of the photoelectric conversion element, and FIG. 9B is a cross-sectional view of the photoelectric conversion element taken along the line AA′ in FIG. 9A. Further, FIG. 9A is a plan view of the photoelectric conversion element in a BB′ cross section of FIG. 9B.

The same components as those of the photoelectric conversion element according to Example 1 are designated by the same reference numerals, and detailed description thereof will be omitted. The photoelectric conversion element according to the present embodiment has an N-type impurity region 110 (N-type semiconductor region) different from the deep isolation region 103. Here, the N-type impurity region 110 is surrounded by the non-isolation region 104. At this time, it is preferable that the relationship of the size W1 of the pixel 100'<the size W2 of the opening of the deep isolation region 103 is satisfied, but this condition may not be satisfied.

Further, in FIG. 9, the N-type impurity region 110 is formed so as to be surrounded by the non-separation region 104 of the pixel 100 ′ that receives near infrared light. However, the present invention is not limited to this, and the N-type impurity region 110 may be formed in the entire pixel region including the pixel 100 that receives visible light.

Thus, the photoelectric conversion element having the N-type impurity region 110 further suppresses (eliminates) the potential barrier of the non-isolation region 104 caused by the deep isolation region 103.

<Example 3>
The photoelectric conversion element according to this example will be described with reference to FIG. FIG. 10A is a plan view of the photoelectric conversion element according to this example, and FIG. 10B is a cross-sectional view of the photoelectric conversion element taken along the line AA′ of FIG. 10A is a plan view of the photoelectric conversion element taken along the line BB′ of FIG. 10B.

In the photoelectric conversion element according to the first embodiment, in the pixel 100 that receives visible light, the charge storage capacity is formed by the deep isolation region 103 formed below the charge storage portion 101 and containing a large amount of P-type impurities. .. On the other hand, the pixel 100' that receives near-infrared light does not have a region containing a large amount of P-type impurities under the charge storage portion 101', so that the charge storage capacity is correspondingly small.

Therefore, in the present embodiment, the P-type impurity region 111 containing a large amount of P-type impurities is formed between the charge storage units 101 and 101′ and the deep isolation region 103 and the non-isolation region 104. According to this, it is possible to increase the capacitances formed under the charge storage units 101 and 101′ and to equalize these capacitances.

<Example 4>
An imaging system according to Example 4 of the present invention will be described with reference to FIG. FIG. 11 is a block diagram showing a schematic configuration of the image pickup system according to the present embodiment.

The photoelectric conversion elements described in the first to third embodiments can be applied to various image pickup systems. The applicable imaging system is not particularly limited, but various types such as a digital still camera, a digital camcorder, a surveillance camera, a copying machine, a fax machine, a mobile phone, an in-vehicle camera, an observation satellite, and a medical camera can be used. Equipment. A camera module including an optical system such as a lens and an imaging device (photoelectric conversion device) is also included in the imaging system. FIG. 11 illustrates a block diagram of a digital still camera as an example of these.

As shown in FIG. 11, the imaging system 2000 includes an imaging device 2001, an imaging optical system 2002, a CPU 2010, a lens control unit 2012, an imaging device control unit 2014, and an image processing unit 2016. The imaging system 2000 also includes an aperture shutter control unit 2018, a display unit 2020, operation switches 2022, and a recording medium 2024.

The imaging optical system 2002 is an optical system for forming an optical image of a subject, and includes a lens group, a diaphragm 2004, and the like. The diaphragm 2004 has a function of adjusting the light amount at the time of shooting by adjusting the aperture diameter thereof, and also has a function as a shutter for adjusting exposure time at the time of shooting a still image. The lens group and the diaphragm 2004 are held so as to be able to move back and forth along the optical axis direction, and a variable magnification function (zoom function) and a focus adjustment function are realized by these linked operations. The image pickup optical system 2002 may be integrated with the image pickup system or may be an image pickup lens attachable to the image pickup system.

In the image space of the image pickup optical system 2002, an image pickup device 2001 is arranged so that its image pickup surface is located. The imaging device 2001 is the photoelectric conversion element described in the first to third embodiments, and includes a CMOS sensor (pixel portion) and its peripheral circuit (peripheral circuit region). In the image pickup device 2001, pixels having a plurality of photoelectric conversion units are two-dimensionally arranged, and color filters are arranged for these pixels to form a two-dimensional single-plate color sensor. The image pickup apparatus 2001 photoelectrically converts the subject image formed by the image pickup optical system 2002 and outputs it as an image signal or a focus detection signal.

The lens control unit 2012 is for controlling the forward/backward driving of the lens group of the imaging optical system 2002 to perform a zoom operation and focus adjustment, and is configured by a circuit and a processing device configured to realize the function. Has been done. The aperture shutter control unit 2018 is for adjusting the photographing light amount by changing the aperture diameter of the aperture 2004 (by changing the aperture value), and is configured by a circuit and a processing device configured to realize the function. To be done.

The CPU 2010 is a control device in the camera that controls various controls of the camera body, and includes an arithmetic unit, a ROM, a RAM, an A/D converter, a D/A converter, a communication interface circuit, and the like. The CPU 2010 controls the operation of each unit in the camera according to a computer program stored in a ROM or the like, and performs a series of shooting including AF, image pickup, image processing, recording, etc., including detection of the focus state of the image pickup optical system 2002 (focus detection). Perform an action. The CPU 2010 is also a signal processing unit.

The imaging device control unit 2014 is for controlling the operation of the imaging device 2001, A/D converting the signal output from the imaging device 2001, and transmitting the A/D converted signal to the CPU 2010, and is configured to realize those functions. It is composed of a controlled circuit and a control device. The A/D conversion function may be included in the imaging device 2001. The image processing unit 2016 is a processing device that generates an image signal by performing image processing such as γ conversion or color interpolation on the A/D converted signal, and a circuit configured to realize the function or It is composed of a control device. The display unit 2020 is a display device such as a liquid crystal display device (LCD), and displays information about the shooting mode of the camera, a preview image before shooting, a confirmation image after shooting, a focus state at the time of focus detection, and the like. The operation switch 2022 includes a power switch, a release (shooting trigger) switch, a zoom operation switch, a shooting mode selection switch, and the like. The recording medium 2024 is for recording a photographed image or the like, and may be one built in the imaging system or a removable one such as a memory card.

In this way, by configuring the imaging system 2000 to which the photoelectric conversion elements according to the first to third embodiments are applied, a high-performance imaging system can be realized.

<Example 5>
An imaging system and a moving body according to a fifth embodiment of the present invention will be described with reference to FIGS. 12(A) and 12(B). 12A and 12B are diagrams showing the configurations of the imaging system and the moving body according to the present embodiment.

FIG. 12A shows an example of the imaging system 2100 relating to the vehicle-mounted camera. The imaging system 2100 has an imaging device 2110. The imaging device 2110 is any of the photoelectric conversion elements described in the first to third embodiments. The imaging system 2100 has an image processing unit 2112 and a parallax acquisition unit 2114. The image processing unit 2112 is a processing device that performs image processing on a plurality of image data acquired by the imaging device 2110. The parallax acquisition unit 2114 is a processing device that calculates parallax (phase difference of parallax images) from a plurality of image data acquired by the imaging device 2110. Further, the imaging system 2100 determines whether or not there is a possibility of collision based on the calculated distance and a distance acquisition unit 2116 that is a processing device that calculates the distance to the target object based on the calculated parallax. And a collision determination unit 2118 which is a processing device. Here, the parallax acquisition unit 2114 and the distance acquisition unit 2116 are an example of an information acquisition unit that acquires information such as distance information to an object. That is, the distance information is information regarding the parallax, the defocus amount, the distance to the object, and the like. The collision determination unit 2118 may determine the possibility of collision using any of these pieces of distance information. The above-described processing device may be realized by dedicated hardware designed or may be realized by general-purpose hardware that performs an operation based on a software module. In addition, the processing device may be realized by an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or the like. Alternatively, the processing device may be realized by a combination of these.

The imaging system 2100 is connected to the vehicle information acquisition device 2120 and can acquire vehicle information such as vehicle speed, yaw rate, and steering angle. Further, the imaging system 2100 is connected to a control ECU 2130 that is a control device that outputs a control signal for generating a braking force to the vehicle based on the determination result of the collision determination unit 2118. That is, the control ECU 2130 is an example of a moving body control unit that controls the moving body based on the distance information. The imaging system 2100 is also connected to an alarm device 2140 that issues an alarm to the driver based on the determination result of the collision determination unit 2118. For example, when there is a high possibility of collision as a result of the determination by the collision determination unit 2118, the control ECU 2130 performs vehicle control for avoiding a collision and reducing damage by braking, returning the accelerator, suppressing the engine output, and the like. The alarm device 2140 sounds a warning such as a sound, displays alarm information on a screen of a car navigation system, gives a vibration to a seat belt or a steering wheel, and warns the user.

In this embodiment, the image capturing system 2100 captures an image around the vehicle, for example, the front or the rear. FIG. 12B shows an imaging system 2100 in the case of imaging the front of the vehicle (imaging range 2150). The vehicle information acquisition device 2120 sends an instruction to operate the imaging system 2100 and execute imaging. By using the photoelectric conversion elements according to the first to third embodiments described above as the image pickup device 2110, the image pickup system 2100 of the present embodiment can further improve the distance measurement accuracy.

In the above description, an example of controlling so as not to collide with other vehicles has been described, but it is also applicable to control for automatically driving by following other vehicles, control for automatically driving so as not to stick out of the lane, etc. is there. Furthermore, the imaging system is not limited to vehicles such as automobiles, but can be applied to moving bodies (transportation equipment) such as ships, aircraft, or industrial robots. A moving device in a moving body (transport device) is various drive sources such as an engine, a motor, wheels, and a propeller. In addition, the present invention can be applied not only to mobile objects but also to devices that widely use object recognition, such as intelligent transportation systems (ITS).

(Other embodiments)
The configurations and processes described in the respective embodiments and modifications of the present invention described above can be used in any combination.

100: pixel, 100': pixel, 101: charge storage part, 101': charge storage part 103: deep separation region, 104: non-separation region

Claims (14)

A first charge storage portion that is a semiconductor region of a first conductivity type;
A second charge storage portion which is the first conductivity type semiconductor region;
An isolation region formed under the first charge storage unit, the isolation region including a second conductivity type semiconductor region having a conductivity type different from the first conductivity type;
A non-separation region formed of a semiconductor region formed below the second charge storage unit and having a lower potential for electric charges than the separation region;
Have
The separation region and the non-separation region are provided at the same height,
In a plan view, the non-separation area is surrounded by the separation area,
In plan view, the size of the opening of the separation region surrounding the non-separation region is larger than the size of the pixel having the second charge storage unit.
A photoelectric conversion element characterized by the above. The size of the opening of the separation region is the size of the non-separation region,
The photoelectric conversion element according to claim 1, wherein: A photoelectric conversion region for photoelectrically converting light is further formed below the non-separation region,
The second charge storage unit stores the charges photoelectrically converted by the photoelectric conversion region,
The photoelectric conversion element according to claim 1 or 2, characterized in that. The semiconductor region of the first conductivity type, which is surrounded by the non-separation region in plan view, is further formed.
The photoelectric conversion element according to claim 1, wherein the photoelectric conversion element is a photoelectric conversion element. The pixel having the first charge storage portion and the pixel having the second charge storage portion are
A pixel separation region that surrounds the first charge storage unit and the second charge storage unit in plan view and separates adjacent pixels from each other;
The photoelectric conversion element according to claim 1, wherein the photoelectric conversion element is a photoelectric conversion element. In plan view, a part of the non-separation region is surrounded by the pixel separation region. In plan view, the size of the opening in which the pixel separation region surrounds the non-separation region has the second charge storage portion. Larger than pixel size,
The photoelectric conversion element according to claim 5, wherein A region that forms a capacitance for storing charges is formed between the first charge storage unit and the second charge storage unit, and the separation region and the non-separation region.
The photoelectric conversion element according to claim 1, wherein the photoelectric conversion element is a photoelectric conversion element. By implanting an impurity of the second conductivity type different from the first conductivity type into the semiconductor substrate of the first conductivity type, a non-separation region that is a region where the impurities of the second conductivity type are not implanted in a plan view. A separation area forming step of forming a separation area surrounding the
A first charge storage part for storing charges is formed on the separation region,
A step of forming a second charge storage part for storing charges on the non-separation region,
Have
In the separation area forming step,
In plan view, the opening of the separation region surrounding the non-separation region is formed larger than the size of the pixel having the second charge storage unit formed in the storage unit formation step.
A method for manufacturing a photoelectric conversion element, comprising: The method further includes a pixel separation forming step of forming a pixel separation region that separates adjacent pixels in the pixel having the first charge storage section and the pixel having the second charge storage section,
In the accumulation part forming step,
The first charge storage section and the second charge storage section are formed at a position surrounded by the pixel separation region in plan view,
The method for manufacturing a photoelectric conversion element according to claim 8, wherein. In the pixel separation forming step,
Forming the pixel isolation region by implanting the second conductivity type impurity into the semiconductor substrate;
The method for manufacturing a photoelectric conversion element according to claim 9, wherein. In the pixel separation forming step,
Forming a pixel isolation region by forming a trench in the semiconductor substrate;
The method for manufacturing a photoelectric conversion element according to claim 9, wherein. In the accumulation part forming step,
Implanting the first conductivity type impurity into the semiconductor substrate to form the first charge storage portion and the second charge storage portion,
The method for manufacturing a photoelectric conversion element according to any one of claims 8 to 11, characterized in that. A photoelectric conversion element according to any one of claims 1 to 7,
A signal processing unit that processes a signal output from the photoelectric conversion element,
An imaging system comprising: Is a mobile,
A photoelectric conversion element according to any one of claims 1 to 7,
A mobile device,
A processing device that acquires information from a signal output from the photoelectric conversion element,
A control device for controlling the mobile device based on the information;
A mobile body having:

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