WO2022080124A1 - Imaging device and manufacturing method for imaging device - Google Patents

Abstract

Provided is an imaging device capable of exhibiting better imaging performance. This imaging device comprises: a semiconductor substrate which includes a first surface and a second surface positioned on the opposite side from the first surface in the thickness direction, and which has a first region part and a second region part that are adjacent in the in-plane direction along the first surface and the second surface; a separation part which extends from the first surface and along thickness direction so as to divide the first region part and the second region part from each other; a first photoelectric conversion part which is provided in the first region part and which is capable of producing a first charge by detecting first light that enters from the first surface and performing photoelectric conversion thereof; a second photoelectric conversion part which is provided in the second region part and which is capable of producing a second charge by detecting second light that enters from the first surface and performing photoelectric conversion thereof; and a charge path part which is provided to a position that is between the separation part and the second surface and that overlaps with the separation part in the thickness direction, and which is provided such that the first charge and the second charge can pass therethrough.

Description

Image pickup device and manufacturing method of image pickup device

The present disclosure relates to an image pickup apparatus that performs imaging by performing photoelectric conversion and a manufacturing method thereof.

So far, a solid-state image sensor has been proposed in which adjacent pixels are separated by a separation portion extending along the thickness direction of the semiconductor substrate (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-168566

By the way, in such an image pickup device, it is required to suppress deterioration of an image.

Therefore, it is desired to provide an image pickup device capable of exhibiting more excellent image pickup performance and a manufacturing method thereof.

An image pickup apparatus as an embodiment of the present disclosure includes a first surface and a second surface located opposite to the first surface in the thickness direction, and the first surface and the second surface. A semiconductor substrate having a first region portion and a second region portion adjacent to each other along the same direction extends along a thickness direction from a first surface so as to separate the first region portion and the second region portion. A separation light-shielding wall and a first photoelectric conversion unit provided in the first region portion and capable of generating a first charge by detecting first light incident from the first surface and performing photoelectric conversion. , A second photoelectric conversion unit provided in the second region portion and capable of generating a second charge by detecting the second light incident from the first surface and performing photoelectric conversion, and a separation light-shielding wall. It has a charge path portion provided between the surface and the second surface and provided so that the first charge and the second charge can pass through.

It is a block diagram which shows the structural example of the image pickup apparatus which concerns on one Embodiment of this disclosure. It is sectional drawing which shows typically the sectional structure of one unit pixel in the image pickup apparatus shown in FIG. 1. It is a top view which schematically shows the plane composition in the semiconductor substrate among the unit pixels shown in FIG. It is a top view which schematically shows the plane composition in the wiring layer among the unit pixels shown in FIG. It is a circuit diagram which shows the circuit structure in the unit pixel shown in FIG. It is a characteristic diagram which shows the relationship between the output in the unit pixel shown in FIG. 2 and the incident angle of incident light. It is sectional drawing which shows typically one step of the manufacturing method of the image pickup apparatus shown in FIG. FIG. 3 is a cross-sectional view schematically showing one step following FIG. 7A in the manufacturing method of the image pickup apparatus shown in FIG. 1. FIG. 3 is a cross-sectional view schematically showing one step following FIG. 7B in the manufacturing method of the image pickup apparatus shown in FIG. 1. FIG. 3 is a cross-sectional view schematically showing one step following FIG. 7C in the manufacturing method of the image pickup apparatus shown in FIG. 1. FIG. 3 is a cross-sectional view schematically showing one step following FIG. 7D in the manufacturing method of the image pickup apparatus shown in FIG. 1. FIG. 3 is a cross-sectional view schematically showing one step following FIG. 7E in the manufacturing method of the image pickup apparatus shown in FIG. 1. It is sectional drawing which shows typically the sectional structure of the unit pixel as the 1st modification of one Embodiment. It is a schematic diagram which shows the whole structure example of the electronic device. It is a block diagram which shows an example of the schematic structure of a vehicle control system. It is explanatory drawing which shows an example of the installation position of the vehicle exterior information detection unit and the image pickup unit. It is a top view which shows the plane composition of the unit pixel as the 2nd modification of this disclosure schematically. It is a top view schematically showing the plane composition of the unit pixel as the 3rd modification of this disclosure. It is a top view which schematically shows the plane composition of the unit pixel as the 4th modification of this disclosure. It is a top view schematically showing the plane composition of the unit pixel as the 5th modification of this disclosure. It is a top view which shows the plane composition of the unit pixel as the sixth modification of this disclosure schematically. It is a top view schematically showing the plane composition of the unit pixel as the 7th modification of this disclosure. It is a top view which schematically shows the plane composition of the unit pixel as the 8th modification of this disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The explanation will be given in the following order.
1. 1. One Embodiment An example of a solid-state image pickup device in which a blooming path is provided on the surface side of a region separation portion that separates two region portions.
2. 2. First Modification Example An example of a solid-state image sensor in which an insulating layer is further provided between the blooming path and the wiring layer.
3. 3. Application example to electronic devices 4. Application example to mobile body 5. Other variants

<1. Embodiment>
[Structure of solid-state image sensor 101]
FIG. 1 is a block diagram showing a configuration example of a function of the solid-state image sensor 101 according to an embodiment of the present technology.

The solid-state image sensor 101 is, for example, a back-illuminated image sensor using CMOS (Complementary Metal Oxide Semiconductor). The solid-state image sensor 101 receives light from a subject, performs photoelectric conversion, and generates an image signal to capture an image.

The back-illuminated image sensor is a wiring such as a light receiving surface on which light from a subject is incident and a transistor or the like that drives each pixel by a photoelectric conversion unit such as a photodiode that receives light from the subject and converts it into an electric signal. Refers to an image sensor having a configuration provided between the wiring layer and the wiring layer provided with the above.

The solid-state imaging device 101 includes, for example, a pixel array unit 111, a vertical drive unit 112, a column signal processing unit 113, a data storage unit 119, a horizontal drive unit 114, a system control unit 115, and a signal processing unit 118.

In the solid-state image sensor 101, the pixel array unit 111 has a semiconductor substrate 1 (described later). Peripheral circuits such as the vertical drive unit 112, the column signal processing unit 113, the data storage unit 119, the horizontal drive unit 114, the system control unit 115, and the signal processing unit 118 are, for example, on the same semiconductor substrate 1 as the pixel array unit 111. It is formed.

The pixel array unit 111 has a plurality of unit pixels 110 including a photoelectric conversion unit (described later) that generates and stores light charges according to the amount of light incident from the subject. As shown in FIG. 1, the unit pixels 110 are arranged in the horizontal direction (row direction) and the vertical direction (column direction), respectively. In the pixel array unit 111, the pixel drive line 116 is wired along the row direction for each pixel row consisting of the unit pixels 110 arranged in a row in the row direction, and is composed of the unit pixels 110 arranged in a row in the column direction. A vertical signal line (VSL) 117 is wired along the column direction for each pixel array.

The vertical drive unit 112 includes a shift register, an address decoder, and the like. The vertical drive unit 112 simultaneously drives all of the plurality of unit pixels 110 in the pixel array unit 111 by supplying signals or the like to the plurality of unit pixels 110 via the plurality of pixel drive lines 116, or pixels. Drive in line units.

The vertical drive unit 112 has, for example, two scanning systems, a read scanning system and a sweep scanning system. In order to read a signal from the unit pixel 110, the read-out scanning system selectively scans the unit pixel 110 of the pixel array unit 111 row by row. In the case of row drive (rolling shutter operation), the sweep scan is performed in advance of the read scan for which the read scan is performed by the read scan system by the time of the shutter speed. Further, in the case of global exposure (global shutter operation), batch sweeping is performed prior to batch transfer by the time of the shutter speed.

By the sweep scan by this sweep scan system, unnecessary optical charges are swept out from the photoelectric conversion units PD1 and PD2 (described later) of the unit pixel 110 of the read row. This is called reset. Then, the so-called electronic shutter operation is performed by sweeping out unnecessary charges by this sweep-out scanning system, that is, resetting. Here, the electronic shutter operation refers to an operation in which the optical charges of the photoelectric conversion units PD1 and PD2 are discarded and exposure is newly started, that is, the accumulation of optical charges is newly started.

The signal read by the read operation by the read scan system corresponds to the amount of light incidented after the read operation immediately before or the electronic shutter operation. In the case of row drive, the period from the read timing by the immediately preceding read operation or the sweep timing by the electronic shutter operation to the read timing by the current read operation is the light charge accumulation period in each unit pixel 110, that is, the exposure period. .. In the case of global exposure, the period from batch sweeping to batch transfer is the light charge accumulation period, that is, the exposure period.

The pixel signal output from each unit pixel 110 of the pixel row selectively scanned by the vertical drive unit 112 is supplied to the column signal processing unit 113 through each of the vertical signal lines 117. The column signal processing unit 113 performs predetermined signal processing on the pixel signal output from each unit pixel 110 of the selected row through the vertical signal line 117 for each pixel column of the pixel array unit 111, and after the signal processing, the column signal processing unit 113 performs predetermined signal processing. The pixel signal is temporarily held.

Specifically, the column signal processing unit 113 includes, for example, a shift register and an address decoder, and includes noise removal processing, correlated double sampling processing, and A / D (Analog / Digital) conversion A / D conversion processing of analog pixel signals. Etc. to generate a digital pixel signal. The column signal processing unit 113 supplies the generated pixel signal to the signal processing unit 118.

The horizontal drive unit 114 is composed of a shift register, an address decoder, and the like, and the unit circuit corresponding to the pixel sequence of the column signal processing unit 113 is sequentially selected. By the selective scanning by the horizontal drive unit 114, the pixel signals signal-processed for each unit circuit in the column signal processing unit 113 are sequentially output to the signal processing unit 118.

The system control unit 115 includes a timing generator or the like that generates various timing signals. The system control unit 115 controls the drive of the vertical drive unit 112, the column signal processing unit 113, and the horizontal drive unit 114 based on the timing signal generated by the timing generator.

The signal processing unit 118 temporarily stores data in the data storage unit 119 as necessary, and performs signal processing such as arithmetic processing on the pixel signal supplied from the column signal processing unit 113, and each pixel signal. It outputs an image signal consisting of.

The data storage unit 119 temporarily stores the data necessary for the signal processing when the signal processing unit 118 performs signal processing.

[Structure of unit pixel 110]
(Example of plane configuration and example of cross-section configuration)
Next, a plan configuration example and a cross-sectional configuration example of the unit pixel 110 provided in the pixel array unit 111 of FIG. 1 will be described with reference to FIGS. 2 and 3. FIG. 2 shows a cross-sectional configuration example of one unit pixel 110 among a plurality of unit pixels 110 constituting the pixel array unit 111. FIG. 3 shows an example of cross-sectional configuration of one unit pixel 110. Note that FIG. 2 corresponds to a cross section in the arrow-viewing direction along the II-II cutting line shown in FIG.

As shown in FIGS. 2 and 3, the semiconductor substrate 1 in each unit pixel 110 has a first region portion R1 and a second region portion R2. Both the first region portion R1 and the second region portion R2 have a rectangular outer edge in the XY plane, and it is preferable that the shapes and sizes of the outer edges are equal to each other. The semiconductor substrate 1 is made of a semiconductor material such as Si (silicon). The semiconductor substrate 1 includes a back surface 1BS as a first surface and a front surface 1FS as a second surface. Both the front surface 1FS and the back surface 1BS extend along the XY plane and are located on opposite sides of each other in the thickness direction (Z-axis direction) orthogonal to the XY plane. The first region portion R1 and the second region portion R2 are provided so as to be adjacent to each other in the XY plane, for example, in the Y-axis direction. In this embodiment, the back surface 1BS is an incident surface on which light L from the outside is incident. In each unit pixel 110, the color filter CF and the on-chip lens OCL are provided so as to be laminated in order on the back surface 1BS of the semiconductor substrate 1. Therefore, the light L from the outside passes through the color filter CF and is incident on the back surface 1BS while being focused by the on-chip lens OCL. In the inter-pixel region between adjacent unit pixels 110 in the XY plane, for example, the inter-pixel shading portion 7 may be provided in the same layer as the color filter CF.

A photoelectric conversion unit PD1 is provided in the first region portion R1 of the unit pixel 110. The photoelectric conversion unit PD1 generates a light charge by detecting the light L1 incident on the back surface 1BS and performing photoelectric conversion. Similarly, the photoelectric conversion unit PD2 is provided in the second region portion R2 of the unit pixel 110. The photoelectric conversion unit PD2 detects the light L2 incident from the back surface 1BS and performs photoelectric conversion to generate a light charge. In FIG. 2, the light incident on the first region portion R1 of the light L is described as L1, and the light incident on the second region portion R2 of the light L is described as L2.

The unit pixel 110 is provided with a wall-shaped region separating portion 4 extending from the back surface 1BS along the thickness direction (Z-axis direction) so as to physically separate the first region portion R1 and the second region portion R2. Has been done. The region separation unit 4 physically separates the first region portion R1 and the second region portion R2. The first region portion R1 and the second region portion R2 in the unit pixel 110 are electrically separated from each other, optically separated from each other, or optically and electrically separated from each other by the region separation unit 4. The region separation portion 4 is a single-layer film or a multilayer film of an insulator such as silicon oxide (SiO ₂ ), tantalum pentoxide (Ta ₂ O ₅ ), hafnium oxide (HfO ₂ ), and aluminum oxide (Al ₂ O ₃ ). It may be formed. Further, the region separation portion 4 may be formed of a laminated body of a single-layer film or a multilayer film of an insulator such as tantalum oxide, hafnium oxide, or aluminum oxide, and a silicon oxide film. The region separation unit 4 formed of the insulator can optically and electrically separate the unit pixels 110. The region separation portion 4 may include a void inside thereof. Even in that case, the region separation unit 4 can optically and electrically separate the first region portion R1 and the second region portion R2. Further, the region separating portion 4 may be formed of a metal having a high light-shielding property such as tantalum (Ta), aluminum (Al), silver (Ag), gold (Au) and copper (Cu). In this case, the first region portion R1 and the second region portion R2 can be optically separated. Further, polysilicon can be used as a constituent material of the region separation unit 4.

Further, the unit pixel 110 has a charge path portion 5 provided between the region separation portion 4 and the surface 1FS at a position overlapping with the region separation portion 4 in the thickness direction. Also called a blooming path, the electric charge generated in the photoelectric conversion unit PD1 and the photoelectric conversion unit PD2 passes through the charge path unit 5. Here, it is desirable that the region separation portion 4 and the charge path portion 5 are in contact with each other.

The unit pixel 110 further includes, for example, a pixel separation unit 3 that integrally surrounds the first region portion R1 and the second region portion R2 in the XY plane. Similar to the region separation unit 4, the pixel separation unit 3 has a wall shape extending from the back surface 1BS along the thickness direction (Z-axis direction). That is, the unit pixels 110 are formed one by one in one pixel region partitioned by the pixel separation unit 3. The adjacent unit pixels 110 are electrically separated from each other, optically separated from each other, or optically and electrically separated from each other by the pixel separation unit 3. The pixel separation unit 3 can be formed of, for example, the same material as the region separation unit 4. An insulating portion 6 may be provided between the pixel separating portion 3 and the surface 1FS at a position where the pixel separating portion 3 overlaps with the pixel separating portion 3 in the thickness direction.

The transfer transistor TG1 and the floating diffusion FD1 as the first charge-voltage conversion unit are further provided in the first region portion R1. Similarly, the second region portion R2 is provided with a transfer transistor TG2 and a floating diffusion FD2 as a second charge-voltage conversion unit. As shown in FIG. 2, in the unit pixel 110, for example, the floating diffusion FD1 is provided between the surface 1FS and the photoelectric conversion unit PD1 in the thickness direction (Z-axis direction). Similarly, the floating diffusion FD2 is provided between the surface 1FS and the photoelectric conversion unit PD2 in the thickness direction (Z-axis direction). The floating diffusion FD1 and FD2 are regions that temporarily hold the optical charges generated in the photoelectric conversion units PD1 and PD2 and then transferred via the transfer transistors TG1 and TG2, respectively. Further, the floating diffusion FD1 and FD2 are also floating diffusion regions that convert the optical charges from the photoelectric conversion units PD1 and PD2 into electric signals (for example, voltage signals) and output them.

The charge path portion 5 contains, for example, crystalline silicon or amorphous silicon as the main material. When the charge path portion 5 mainly contains crystalline silicon, for example, the semiconductor substrate 1 which is a Si substrate is annealed in a reducing atmosphere, and the silicon (Si) atom contained in the Si substrate is migrated to migrate the charge path portion. 5 can be formed. Alternatively, the charge path portion 5 mainly containing crystalline silicon may be formed by an epitaxial growth method. Further, when the charge path portion 5 mainly contains amorphous silicon, the charge path portion 5 can be generated by a vapor deposition method such as a sputtering method or a CVD method.

The pixel array unit 111 is further provided with a wiring layer 2 that covers the surface 1FS. FIG. 4 is a schematic plan view showing the layout of the wiring layer 2 in the unit pixel 110. In FIG. 4, the pixel separation unit 3, the region separation unit 4, the photoelectric conversion units PD1, PD2, and the like are shown together by a broken line. Further, FIG. 5 shows an example of a circuit configuration of the unit pixel 110.

As shown in FIG. 4, the wiring layer 2 is provided with transfer transistors TG1 and TG2, a connection portion 11, amplification transistors AMP1 and AMP2, wiring 12, a reset transistor RST, a selection transistor SEL, and the like. The connection portion 11 connects the floating diffusion FD1 and the floating diffusion FD2. The wiring 12 connects the connection portion 11 with the amplification transistor AMP1 and the amplification transistor AMP2. Therefore, the amplification transistor AMP1 and the amplification transistor AMP2 form one amplification transistor AMP via the wiring 12. Here, the transfer transistor TG1, the reset transistor RST, and the amplification transistor AMP1 are provided at positions corresponding to the first region portion R1 in the thickness direction. On the other hand, the transfer transistor TG2, the selection transistor SEL, and the amplification transistor AMP2 are provided at positions corresponding to the second region portion R2 in the thickness direction. In the unit pixel 110, the floating diffusion FD, the reset transistor RST, the selection transistor SEL, and the amplification transistor AMP are shared by the first region portion R1 and the second region portion R2. In FIG. 5, the amplification transistor AMP in which the amplification transistor AMP1 and the amplification transistor AMP2 are integrated is described.

As shown in FIG. 5, in the photoelectric conversion unit PD1, for example, the anode terminal is grounded and the cathode terminal is connected to the floating diffusion FD1 via the transfer transistor TG1. Similarly, in the photoelectric conversion unit PD2, for example, the anode terminal is grounded and the cathode terminal is connected to the floating diffusion FD2 via the transfer transistor TG2.

When the transfer transistors TG1 and TG2 are turned on by the transfer signal, the optical charges generated by the photoelectric conversion units PD1 and PD2 are read out and transferred to the floating diffusion FD1 and FD2, respectively.

The floating diffusion FD1 and FD2 hold the optical charge read from the photoelectric conversion units PD1 and PD2 by the transfer transistors TG1 and TG2. Further, the floating diffusion FD1 and FD2 are adapted to convert their optical charges into electric signals (for example, voltage signals) and output them.

When the reset transistor RST is turned on by the reset signal, the optical charge accumulated in the floating diffusion FD1 and FD2 is discharged to the drain, that is, the constant voltage source Vdd. By doing so, the reset transistor RST resets the potentials of the floating diffusion FD1 and FD2.

The amplification transistor AMP is designed to output a pixel signal corresponding to the potential of the floating diffusion FD1 and FD2. That is, the amplification transistor AMP constitutes a source follower circuit with a constant current source connected via the vertical signal line 117. A pixel signal indicating a level corresponding to the optical charge stored in the floating diffusion FD1 and FD2 is output from the amplification transistor AMP to the column signal processing unit 113 (FIG. 1) via the selection transistor SEL and the vertical signal line 117. It has become so.

The selection transistor SEL is turned on when a certain unit pixel 110 is selected by the selection signal, and the pixel signal of the selected unit pixel 110 is output to the column signal processing unit 113 via the vertical signal line 117. ing. Each signal line through which the transfer signal, the selection signal, and the reset signal are transmitted corresponds to the pixel drive line 116 shown in FIG.

As shown in FIG. 2, in the unit pixel 110, two photoelectric conversion units PD1 and PD2 are directly below one on-chip lens OCL, that is, at a position where one on-chip lens OCL overlaps in the Z-axis direction. It is provided. In the following description, such a structure may be referred to as a 2PD structure.

In the unit pixel 110, the light L incident on the on-chip lens OCL passes through the color filter CF while being focused by the on-chip lens OCL, and then from the back surface 1BS to the photoelectric conversion unit PD1 or the second region of the first region portion R1. The photoelectric conversion unit PD2 of the portion R2 is irradiated. Here, the light that irradiates the photoelectric conversion unit PD1 is referred to as light L1, and the light that irradiates the photoelectric conversion unit PD2 is referred to as light L2.

The ratio of the amount of light L1 irradiating the photoelectric conversion unit PD1 to the amount of light L2 irradiating the photoelectric conversion unit PD2 depends on, for example, the incident angle θ of the light L with respect to the back surface 1BS. FIG. 6 is a characteristic diagram showing the dependence of the output on the change in the incident angle θ of the light L in each of the photoelectric conversion unit PD1 and the photoelectric conversion unit PD2. In FIG. 6, the incident angle θ dependence of the output of the photoelectric conversion unit PD1 is represented by the solid line curve PD1, and the incident angle θ dependence of the output of the photoelectric conversion unit PD2 is represented by the broken line curve PD2. For example, when the light L is vertically incident on the back surface 1BS, that is, when the incident angle θ = 0 °, the light amount of the light L1 and the light amount of the light L2 are equal to each other. Therefore, as shown in FIG. 6, the output of the photoelectric conversion unit PD1 and the output of the photoelectric conversion unit PD2 are equal to each other.

As shown in FIG. 6, the output of the photoelectric conversion unit PD1 and the output of the photoelectric conversion unit PD2 have a symmetrical relationship with respect to the change of the incident angle θ with the incident angle θ = 0 as the center. The output of the photoelectric conversion unit PD1 and the output of the photoelectric conversion unit PD2 can be used, for example, for performing phase difference detection. However, for example, when the light L is intensively irradiating the photoelectric conversion unit PD1, if a part of the light L1 that should be incident on the photoelectric conversion unit PD1 is unintentionally incident on the photoelectric conversion unit PD2, the photoelectric conversion unit PD2 is charged. The output from the conversion unit PD2 may increase, and the accuracy of phase difference detection may decrease.

Therefore, in the unit pixel 110 of the present embodiment, the region separation portion 4 extending in the thickness direction from the back surface 1BS to the front surface 1FS is provided. Therefore, it is possible to avoid mixing the output from the photoelectric conversion unit PD1 and the output from the photoelectric conversion unit PD2, and improve the phase difference detection accuracy.

[Manufacturing method of solid-state image sensor 101]
Next, a method of manufacturing the solid-state image sensor 101 will be described with reference to FIGS. 7A to 7F. 7A to 7F are cross-sectional views schematically showing one step of the manufacturing method of the solid-state image sensor 101, respectively.

First, as shown in FIG. 7A, a semiconductor substrate 1 made of a Si substrate is prepared, and then the pixel separation portion 3 and the region separation portion are selectively dug from the surface 1FS in the thickness direction (Z-axis direction). The trench 1TR is formed at a desired position where each of the 4's should be formed.

Next, as shown in FIG. 7B, the pixel separation portion 3 and the region separation portion 4 and the insulating portion filling the space between the pixel separation portion 3 and the region separation portion 4 and the surface 1FS are provided so as to fill the trench 1TR. Form each.

Next, as shown in FIG. 7C, a hard mask HM made of an insulating film such as SiNx is formed by, for example, a CVD method so as to cover the entire surface 1FS. Further, a resist mask RM that selectively covers the hard mask HM is formed by a photolithography method. The resist mask RM has an opening RM-K at a position where the charge path portion 5 should be formed, that is, immediately above, for example, the region separation portion 4.

Subsequently, as shown in FIG. 7D, the exposed portion of the hard mask HM that is not covered by the resist mask RM is removed by dry etching, for example, and an opening HM-K is formed in the hard mask HM. Further, the insulating portion 6 directly above the region separating portion 4 is removed by wet etching using the hard mask HM having the opening HM-K formed, and the concave portion U is formed. When forming the recess U, the upper end portion of the region separating portion 4 may be removed.

After forming the recess U, the hard mask HM is removed, and as shown in FIG. 7E, the charge path portion 5 is formed so as to fill the recess U. Specifically, the charge path portion 5 can be formed by subjecting the entire semiconductor substrate 1 to an annealing treatment in a reducing atmosphere such as a hydrogen atmosphere and migrating the silicon contained in the semiconductor substrate 1 to the recess U. can. Alternatively, crystalline silicon may be formed in the recess U by the epitaxial growth method without removing the hard mask HM. Alternatively, the charge path portion 5 may be formed by forming amorphous silicon in the recess U by a vapor deposition method without removing the hard mask HM. When the charge path portion 5 is formed by the epitaxial growth method or the vapor deposition method, the hard mask HM is removed after the charge path portion 5 is formed.

The upper end portion of the charge path portion 5 formed so as to fill the recess U does not have to coincide with the surface 1FS. For example, as shown in FIG. 7E, the upper end portion of the charge path portion 5 may protrude from the surface 1FS.

Subsequently, as shown in FIG. 7F, the surface of the semiconductor substrate 1 opposite to the front surface 1FS is polished until the pixel separation portion 3 and the region separation portion 4 are exposed to form the back surface 1BS. Further, the wiring layer 2 including the thin film transistors such as the transfer transistors TG1 and TG2 is formed so as to cover the surface 1FS. Further, the photoelectric conversion units PD1 and PD2 and the floating diffusion FD1 and FD2 are formed in the first region portion R1 and the second region portion R2 of the semiconductor substrate 1.

After that, the solid-state image sensor 101 is completed by forming the color filter CF, the inter-pixel light-shielding portion 7, the on-chip lens OCL, and the like.

[Action and effect of solid-state image sensor 101]
As described above, in the solid-state image sensor 101 of the present embodiment, in each unit pixel 110, a region separation portion 4 extending in the thickness direction from the back surface 1BS of the semiconductor substrate 1 toward the front surface 1FS is provided, and the first region portion is provided. R1 and the second region portion R2 are physically separated. Therefore, it is possible to avoid unintended and unnecessary irradiation of each of the photoelectric conversion unit PD1 provided in the first region portion R1 and the photoelectric conversion unit PD2 provided in the second region portion R2. can. Further, since the charge path portion 5 is provided on the surface 1FS side of the region separation portion 4, the output of the photoelectric conversion unit PD1 and the output of the photoelectric conversion unit PD2 provided in the second region portion R2 are shared. Can be done. As a result, each unit pixel 110 can be used as a phase difference detection pixel for obtaining phase difference information.

If the region separation portion 4 is formed so as to extend from the back surface 1BS of the semiconductor substrate 1 to the front surface 1FS, so-called color separation is possible, but phase difference detection cannot be performed. Further, a physical separation wall may be formed by ion implantation between the first region portion R1 and the second region portion R2 without providing the region separation portion 4, but in that case, the region to be ion-implanted may be formed. Since the occupied area of the photoelectric conversion units PD1 and PD2 is reduced by the amount, the output is reduced. According to the present disclosure, it is possible to detect the phase difference while completely separating the first region portion R1 and the second region portion R2 on the light incident side, and it is possible to obtain a higher output.

Further, in the present disclosure, the trench 1TR is formed on the semiconductor substrate 1 before forming the wiring layer 2 including the thin film transistors such as the transfer transistors TG1 and TG2. Therefore, it is not necessary to damage the thin film transistor included in the wiring layer 2 due to the formation of the trench 1TR. Further, after forming the trench 1TR, thermal annealing can be performed, and crystal defects such as strain generated in the semiconductor substrate 1 can be recovered. That is, it is possible to reduce the damage in the semiconductor substrate 1 due to processing. As a result, the solid-state image sensor 101 of the present disclosure has high reliability. On the other hand, for example, when a trench is formed from the back surface 1BS, the trench is formed with the wiring layer 2 formed on the front surface 1FS, so that thermal annealing can be performed in order to avoid damage to the wiring layer 2. It is practically difficult to expose to a high temperature environment.

<2. First variant>
Next, with reference to FIG. 8, the unit pixel 110A as a first modification of the above embodiment will be described. FIG. 8 is a schematic view showing a cross-sectional configuration example of the unit pixel 110A, and corresponds to FIG. 2 showing the unit pixel 110 described in the above embodiment. The unit pixel 110A has substantially the same configuration as the unit pixel 110 of FIG. 2 except that it further has an insulating layer 8 provided between the charge path portion 5 and the wiring layer 2.

Specifically, the unit pixel 110A is provided with an insulating layer 8 so as to be in contact with both the charge path portion 5 and the wiring layer 2 so as to overlap the charge path portion 5 in the thickness direction.

Since the insulating layer 8 is provided in the unit pixel 110A in this way, it is possible to sufficiently perform electrical insulation between the charge path portion 5 and the wiring layer 2. Therefore, it is possible to prevent the optical charges from the photoelectric conversion units PD1 and PD2 from flowing out to the wiring layer 2 by an unintended path. Therefore, it is possible to secure higher operation reliability than the unit pixel 110 of the above embodiment.

<3. Application example to electronic devices>
FIG. 9 is a block diagram showing a configuration example of the camera 2000 as an electronic device to which the present technology is applied.

The camera 2000 is an optical unit 2001 composed of a lens group or the like, an image pickup device (imaging device) 2002 to which the above-mentioned solid-state image pickup device 101 or the like (hereinafter referred to as a solid-state image pickup device 101 or the like) is applied, and a camera signal processing circuit. A DSP (Digital Signal Processor) circuit 2003 is provided. The camera 2000 also includes a frame memory 2004, a display unit 2005, a recording unit 2006, an operation unit 2007, and a power supply unit 2008. The DSP circuit 2003, the frame memory 2004, the display unit 2005, the recording unit 2006, the operation unit 2007, and the power supply unit 2008 are connected to each other via the bus line 2009.

The optical unit 2001 captures incident light (image light) from the subject and forms an image on the image pickup surface of the image pickup apparatus 2002. The image pickup apparatus 2002 converts the amount of incident light imaged on the image pickup surface by the optical unit 2001 into an electric signal in pixel units and outputs it as a pixel signal.

The display unit 2005 comprises a panel-type display device such as a liquid crystal panel or an organic EL panel, and displays a moving image or a still image captured by the image pickup device 2002. The recording unit 2006 records a moving image or a still image captured by the image pickup apparatus 2002 on a recording medium such as a hard disk or a semiconductor memory.

The operation unit 2007 issues operation commands for various functions of the camera 2000 under the operation of the user. The power supply unit 2008 appropriately supplies various power sources that serve as operating power sources for the DSP circuit 2003, the frame memory 2004, the display unit 2005, the recording unit 2006, and the operation unit 2007 to these supply targets.

As described above, good image acquisition can be expected by using the above-mentioned solid-state image pickup device 101 or the like as the image pickup device 2002.

<4. Application example to mobile>
The technique according to the present disclosure (the present technique) can be applied to various products. For example, the technology according to the present disclosure is realized as a device mounted on a moving body of any kind such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility, an airplane, a drone, a ship, and a robot. You may.

FIG. 10 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technique according to the present disclosure can be applied.

The vehicle control system 12000 includes a plurality of electronic control units connected via the communication network 12001. In the example shown in FIG. 10, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside information detection unit 12030, an in-vehicle information detection unit 12040, and an integrated control unit 12050. Further, as a functional configuration of the integrated control unit 12050, a microcomputer 12051, an audio image output unit 12052, and an in-vehicle network I / F (Interface) 12053 are shown.

The drive system control unit 12010 controls the operation of the device related to the drive system of the vehicle according to various programs. For example, the drive system control unit 12010 has a driving force generator for generating the driving force of the vehicle such as an internal combustion engine or a driving motor, a driving force transmission mechanism for transmitting the driving force to the wheels, and a steering angle of the vehicle. It functions as a control device such as a steering mechanism for adjusting and a braking device for generating braking force of the vehicle.

The body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a keyless entry system, a smart key system, a power window device, or a control device for various lamps such as headlamps, back lamps, brake lamps, turn signals or fog lamps. In this case, the body system control unit 12020 may be input with radio waves transmitted from a portable device that substitutes for the key or signals of various switches. The body system control unit 12020 receives inputs of these radio waves or signals and controls a vehicle door lock device, a power window device, a lamp, and the like.

The vehicle outside information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, the image pickup unit 12031 is connected to the vehicle outside information detection unit 12030. The vehicle outside information detection unit 12030 causes the image pickup unit 12031 to capture an image of the outside of the vehicle and receives the captured image. The vehicle outside information detection unit 12030 may perform object detection processing or distance detection processing such as a person, a vehicle, an obstacle, a sign, or a character on the road surface based on the received image.

The image pickup unit 12031 is an optical sensor that receives light and outputs an electric signal according to the amount of the light received. The image pickup unit 12031 can output an electric signal as an image or can output it as distance measurement information. Further, the light received by the image pickup unit 12031 may be visible light or invisible light such as infrared light.

The in-vehicle information detection unit 12040 detects the in-vehicle information. For example, a driver state detection unit 12041 that detects a driver's state is connected to the vehicle interior information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that images the driver, and the in-vehicle information detection unit 12040 determines the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041. It may be calculated, or it may be determined whether or not the driver has fallen asleep.

The microcomputer 12051 calculates the control target value of the driving force generator, the steering mechanism, or the braking device based on the information inside and outside the vehicle acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, and the drive system control unit. A control command can be output to 12010. For example, the microcomputer 12051 realizes ADAS (Advanced Driver Assistance System) functions including vehicle collision avoidance or impact mitigation, follow-up driving based on inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane deviation warning, and the like. It is possible to perform cooperative control for the purpose of.

Further, the microcomputer 12051 controls the driving force generating device, the steering mechanism, the braking device, and the like based on the information around the vehicle acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040. It is possible to perform coordinated control for the purpose of automatic driving that runs autonomously without depending on the operation.

Further, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the vehicle outside information detection unit 12030. For example, the microcomputer 12051 controls the headlamps according to the position of the preceding vehicle or the oncoming vehicle detected by the outside information detection unit 12030, and performs cooperative control for the purpose of anti-glare such as switching the high beam to the low beam. It can be carried out.

The audio image output unit 12052 transmits an output signal of at least one of audio and image to an output device capable of visually or audibly notifying information to the passenger or the outside of the vehicle. In the example of FIG. 10, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are exemplified as output devices. The display unit 12062 may include, for example, at least one of an onboard display and a head-up display.

FIG. 11 is a diagram showing an example of the installation position of the image pickup unit 12031.

In FIG. 11, as the image pickup unit 12031, the image pickup units 12101, 12102, 12103, 12104, and 12105 are included.

The image pickup units 12101, 12102, 12103, 12104, 12105 are provided at positions such as, for example, the front nose, side mirrors, rear bumpers, back doors, and the upper part of the windshield in the vehicle interior of the vehicle 12100. The image pickup unit 12101 provided on the front nose and the image pickup section 12105 provided on the upper part of the windshield in the vehicle interior mainly acquire an image in front of the vehicle 12100. The image pickup units 12102 and 12103 provided in the side mirror mainly acquire images of the side of the vehicle 12100. The image pickup unit 12104 provided in the rear bumper or the back door mainly acquires an image of the rear of the vehicle 12100. The image pickup unit 12105 provided on the upper part of the windshield in the vehicle interior is mainly used for detecting a preceding vehicle, a pedestrian, an obstacle, a traffic light, a traffic sign, a lane, or the like.

Note that FIG. 11 shows an example of the shooting range of the imaging units 12101 to 12104. The imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, the imaging ranges 12112 and 12113 indicate the imaging range of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and the imaging range 12114 indicates the imaging range. The imaging range of the imaging unit 12104 provided on the rear bumper or the back door is shown. For example, by superimposing the image data captured by the imaging units 12101 to 12104, a bird's-eye view image of the vehicle 12100 can be obtained.

At least one of the image pickup units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the image pickup units 12101 to 12104 may be a stereo camera including a plurality of image pickup elements, or may be an image pickup element having pixels for phase difference detection.

For example, the microcomputer 12051 has a distance to each three-dimensional object within the image pickup range 12111 to 12114 based on the distance information obtained from the image pickup unit 12101 to 12104, and a temporal change of this distance (relative speed with respect to the vehicle 12100). By obtaining, it is possible to extract a three-dimensional object that is the closest three-dimensional object on the traveling path of the vehicle 12100 and travels in substantially the same direction as the vehicle 12100 at a predetermined speed (for example, 0 km / h or more) as a preceding vehicle. can. Further, the microcomputer 12051 can set an inter-vehicle distance to be secured in advance in front of the preceding vehicle, and can perform automatic brake control (including follow-up stop control), automatic acceleration control (including follow-up start control), and the like. In this way, it is possible to perform coordinated control for the purpose of automatic driving or the like that autonomously travels without relying on the driver's operation.

For example, the microcomputer 12051 converts three-dimensional object data related to a three-dimensional object into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, electric poles, and other three-dimensional objects based on the distance information obtained from the image pickup units 12101 to 12104. It can be classified and extracted and used for automatic avoidance of obstacles. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. Then, the microcomputer 12051 determines the collision risk indicating the risk of collision with each obstacle, and when the collision risk is equal to or higher than the set value and there is a possibility of collision, the microcomputer 12051 via the audio speaker 12061 or the display unit 12062. By outputting an alarm to the driver and performing forced deceleration and avoidance steering via the drive system control unit 12010, driving support for collision avoidance can be provided.

At least one of the image pickup units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether or not a pedestrian is present in the captured image of the imaging unit 12101 to 12104. Such pedestrian recognition is, for example, a procedure for extracting feature points in an image captured by an image pickup unit 12101 to 12104 as an infrared camera, and pattern matching processing is performed on a series of feature points indicating the outline of an object to determine whether or not the pedestrian is a pedestrian. It is done by the procedure to determine. When the microcomputer 12051 determines that a pedestrian is present in the captured image of the image pickup unit 12101 to 12104 and recognizes the pedestrian, the audio image output unit 12052 determines the square contour line for emphasizing the recognized pedestrian. The display unit 12062 is controlled so as to superimpose and display. Further, the audio image output unit 12052 may control the display unit 12062 so as to display an icon or the like indicating a pedestrian at a desired position.

The above is an example of a vehicle control system to which the technique according to the present disclosure can be applied. The technique according to the present disclosure can be applied to the image pickup unit 12031 among the configurations described above. Specifically, the solid-state image sensor 101 or the like shown in FIG. 1 or the like can be applied to the image pickup unit 12031. By applying the technique according to the present disclosure to the image pickup unit 12031, excellent operation of the vehicle control system can be expected.

<5. Other variants>
Although the present disclosure has been described above with reference to some embodiments and modifications, the present disclosure is not limited to the above embodiments and the like, and various modifications are possible. For example, in the unit pixel 110 of the above embodiment, the charge path portion 5 is formed only in a part of the region overlapping with the region separation portion 4 in the thickness direction, but the image pickup apparatus of the present disclosure is limited to this. It's not a thing. For example, as in the unit pixel 110B as the second modification shown in FIG. 12, the charge path portion 5 may be formed so as to occupy the entire region overlapping with the region separation portion 4 in the thickness direction.

Further, the present disclosure is not limited to the arrangement position of the transfer transistor and the floating diffusion as shown in the above embodiment. For example, as in the unit pixel 110C as the third modification shown in FIG. 13, the floating diffusion FD1 and FD2 may be provided at positions away from the region separation unit 4, respectively.

Further, in the above embodiment, the case where one unit pixel has two region portions separated by one region separation unit has been described, but the present disclosure is not limited to this. For example, like the unit pixel 110D as the fourth modification and the unit pixel 110E as the fifth modification shown in FIGS. 14 and 15, respectively, two wall-shaped portions in which one unit pixel intersects with each other, for example. It may have four first-fourth region portions R1 to R4 separated by the region separation part 9 made of. The unit pixel 110D is an example in which the charge path portion 5 is provided only in a part of the region overlapping the region separation portion 9 in the thickness direction. Further, the unit pixel 110E is an example in which the charge path portion 5 is provided so as to occupy the entire region overlapping with the region separation portion 9 in the thickness direction.

Further, in the above embodiment, the wiring layer 2 including the transfer transistors TG1 and TG2, the connection portion 11, the amplification transistors AMP1 and AMP2, the wiring 12, and the like is provided on the surface 1FS of the semiconductor substrate 1 of the unit pixel 110. By way of example, the present disclosure is not limited to this. The image pickup apparatus of the present disclosure may include a laminated structure such as the unit pixel 110F as the sixth modification of the present disclosure shown in FIG. 16, for example.

FIG. 16 shows an example of the cross-sectional configuration of the unit pixel 110F as the sixth modification of the present disclosure. The image pickup apparatus provided with a plurality of unit pixels 110F has a structure in which the first substrate 10, the second substrate 20, and the third substrate 30 are laminated in order. The image pickup apparatus provided with a plurality of unit pixels 110F further includes a color filter CF and an on-chip lens OCL on the back surface side of the first substrate 10, that is, the light incident surface side.

The first substrate 10 is configured by laminating an insulating layer 46 on a semiconductor substrate 1. The first substrate 10 has an insulating layer 46 as a part of the interlayer insulating film 51. The insulating layer 46 is provided in the gap between the semiconductor substrate 1 and the semiconductor substrate 21 of the second substrate 20. The insulating layer 46 is provided with transfer transistors TG1 and TG2, floating diffusion FD1 and FD2, and the like.

The second substrate 20 is configured by laminating an insulating layer 52 on a semiconductor substrate 21. The second substrate 20 has an insulating layer 52 as a part of the interlayer insulating film 51. The insulating layer 52 is provided in the gap between the semiconductor substrate 21 and the semiconductor substrate 31 of the third substrate 30. The semiconductor substrate 21 is made of, for example, a silicon substrate. The readout circuit 22 is provided on the surface side of the semiconductor substrate 21 of the second substrate 20, that is, the portion on the third substrate 30 side. The second substrate 20 is attached to the first substrate 10 with the back surface of the semiconductor substrate 21 facing the front surface side of the semiconductor substrate 1. That is, the second substrate 20 is face-to-back bonded to the first substrate 10. The second substrate 20 further has an insulating layer 53 penetrating the semiconductor substrate 21 in the same layer as the semiconductor substrate 21. The second substrate 20 has an insulating layer 53 as a part of the interlayer insulating film 51. The insulating layer 53 is provided so as to cover the side surface of the through wiring 54 described later.

The laminate composed of the first substrate 10 and the second substrate 20 has an interlayer insulating film 51 and a through wiring 54 provided in the interlayer insulating film 51. One through wiring 54 is provided for each of the first region portion R1 and the second region portion R2. The through wiring 54 extends in the thickness direction (Z-axis direction) of the semiconductor substrate 21 so as to penetrate the insulating layer 53 of the interlayer insulating film 51. The first substrate 10 and the second substrate 20 are electrically connected to each other by a through wiring 54. Specifically, the through wiring 54 is provided so as to electrically connect the floating diffusion FD and the connection wiring 55 described later.

The second substrate 20 has, for example, a plurality of connecting portions 59 electrically connected to the readout circuit 22 and the semiconductor substrate 21 in the insulating layer 52. The second substrate 20 further has, for example, a wiring layer 56 on the insulating layer 52. The wiring layer 56 has, for example, an insulating layer 57, a plurality of pixel drive lines 23 provided in the insulating layer 57, and a plurality of vertical signal lines 24. The wiring layer 56 further has, for example, a plurality of connection wirings 55 in the insulating layer 57. The connection wiring 55 electrically connects two through wirings 54 electrically connected to the floating diffusion FD1 and FD2, respectively.

The wiring layer 56 further has, for example, a plurality of pad electrodes 58 in the insulating layer 57. Each pad electrode 58 is made of a metal such as Cu (copper) or Al (aluminum). Each pad electrode 58 is exposed on the surface of the wiring layer 56. The plurality of pad electrodes 58 are joined to a plurality of pad electrodes 64, which will be described later, respectively, for electrical connection between the second substrate 20 and the third substrate 30, and bonding of the second substrate 20 and the third substrate 30. Used for. The plurality of pad electrodes 58 are provided, for example, one for each of the pixel drive line 23 and the vertical signal line 24.

The third substrate 30 is configured by, for example, laminating an interlayer insulating film 61 on a semiconductor substrate 31. The semiconductor substrate 31 is made of a silicon substrate. The third substrate 30 has a configuration in which a logic circuit 32 is provided on a portion on the surface side of the semiconductor substrate 31. The third substrate 30 further has, for example, a wiring layer 62 on the interlayer insulating film 61. The wiring layer 62 has, for example, an insulating layer 63 and a plurality of pad electrodes 64 provided in the insulating layer 63. The plurality of pad electrodes 64 are electrically connected to the logic circuit 32. Each pad electrode 64 is made of, for example, Cu (copper). Each pad electrode 64 is exposed on the surface of the wiring layer 62. Each pad electrode 64 is used for electrical connection between the second substrate 20 and the third substrate 30 and for bonding the second substrate 20 and the third substrate 30. Further, the number of pad electrodes 64 does not necessarily have to be plurality, and even one pad electrode 64 can be electrically connected to the logic circuit 32. The second substrate 20 and the third substrate 30 are electrically connected to each other by joining the pad electrode 58 and the pad electrode 64. That is, the transfer transistors TG1 and TG2 are electrically connected to the logic circuit 32 via the through wiring 54 and the pad electrodes 58 and 64. The third substrate 30 is attached to the second substrate 20 with the surface of the semiconductor substrate 31 facing the surface side of the semiconductor substrate 21. That is, the third substrate 30 is attached to the second substrate 20 face-to-face.

The image pickup apparatus of the present disclosure may include a laminated structure such as a unit pixel 110G as a seventh modification of the present disclosure shown in FIG. 17, for example.

FIG. 17 shows an example of the cross-sectional configuration of the unit pixel 110G as the seventh modification of the present disclosure. The image pickup apparatus provided with a plurality of unit pixels 110G has a structure in which the first substrate 10, the second substrate 20, and the third substrate 30 are laminated in order. The image pickup apparatus provided with a plurality of unit pixels 110G further includes a color filter CF and an on-chip lens OCL on the back surface side of the first substrate 10, that is, the light incident surface side.

The first substrate 10 is configured by laminating the wiring layer 2 on the surface side of the semiconductor substrate 1. The wiring layer 2 is provided in the gap between the semiconductor substrate 1 and the wiring layer 56 of the second substrate 20. The wiring layer 2 is provided with transfer transistors TG1 and TG2, floating diffusion FD1 and FD2, a plurality of pad electrodes 71, a plurality of connection portions 59, and the like. Each pad electrode 71 is exposed on the surface of the wiring layer 2. Each pad electrode 71 is used for electrical connection between the first substrate 10 and the second substrate 20 and for bonding the first substrate 10 and the second substrate 20.

In the second substrate 20, the wiring layer 56 and the interlayer insulating film 51 are laminated in order from the side to be bonded to the first substrate 10. The second substrate 20 is attached to the first substrate 10 with the surface of the semiconductor substrate 21 facing the surface side of the semiconductor substrate 1. That is, the second substrate 20 is face-to-face bonded to the first substrate 10. The wiring layer 56 has, for example, an insulating layer 57, a plurality of pixel drive lines 23 provided in the insulating layer 57, and a plurality of vertical signal lines 24. The wiring layer 56 has, for example, a connection wiring 55 in the insulating layer 57. The connection wiring 55 electrically connects two through wirings electrically connected to the read circuit 22 to each other. The wiring layer 56 further has a plurality of pad electrodes 58 provided so as to be exposed on the surface of the second substrate 20. The plurality of pad electrodes 58 are bonded to the plurality of pad electrodes 71, respectively, and are used for electrical connection between the first substrate 10 and the second substrate 20 and bonding of the first substrate 10 and the second substrate 20. Be done. The interlayer insulating film 51 is configured by laminating the insulating layer 52, the semiconductor substrate 21, and the insulating layer 46 in order from the wiring layer 56 side. The readout circuit 22 is provided on the semiconductor substrate 21. The insulating layer 46 is provided with a plurality of pad electrodes 47 so as to be exposed on the back surface of the second substrate 20. The plurality of pad electrodes 47 are bonded to the plurality of pad electrodes 64 of the third substrate 30, respectively, to electrically connect the second substrate 20 and the third substrate 30, and to connect the second substrate 20 and the third substrate 30. Used for bonding. Further, the second substrate 20 is provided with a connecting portion 59 so as to extend in the Z-axis direction from a part of the pad electrodes 58 to a part of the pad electrodes 47. The connection portion 59 is electrically connected to, for example, the readout circuit 22 or the semiconductor substrate 21. The second substrate 20 further has an insulating layer 53 penetrating the semiconductor substrate 21 in the same layer as the semiconductor substrate 21. The second substrate 20 has an insulating layer 53 as a part of the interlayer insulating film 51.

The third substrate 30 is configured by, for example, laminating an interlayer insulating film 61 on a semiconductor substrate 31. The semiconductor substrate 31 is made of a silicon substrate. The third substrate 30 has a configuration in which a logic circuit 32 is provided on a portion on the surface side of the semiconductor substrate 31. The third substrate 30 further has, for example, a wiring layer 62 on the interlayer insulating film 61. The wiring layer 62 has, for example, an insulating layer 63 and a plurality of pad electrodes 64 provided in the insulating layer 63. The plurality of pad electrodes 64 are electrically connected to the logic circuit 32. The transfer transistors TG1 and TG2 of the first substrate 10 are electrically connected to the logic circuit 32 of the third substrate 30 via the second substrate 20. The third substrate 30 is attached to the second substrate 20 with the front surface of the semiconductor substrate 31 facing the back surface side of the semiconductor substrate 21. That is, the third substrate 30 is attached to the second substrate 20 by face-to-back.

The image pickup apparatus of the present disclosure may include a laminated structure such as a unit pixel 110H as an eighth modification of the present disclosure shown in FIG. 18, for example.

FIG. 18 shows an example of the cross-sectional configuration of the unit pixel 110H as the eighth modification of the present disclosure. The image pickup apparatus provided with a plurality of unit pixels 110H has a structure in which the first substrate 10, the second substrate 20, and the third substrate 30 are laminated in order. The image pickup apparatus provided with a plurality of unit pixels 110H further includes a color filter CF and an on-chip lens OCL on the back surface side of the first substrate 10, that is, the light incident surface side.

The configuration of the unit pixel 110H in FIG. 18 is the unit pixel shown in FIG. 17 except that the second substrate 20 is inserted between the first substrate 10 and the third substrate 30 in an inverted state. It is substantially the same as the configuration of 110G. That is, the second substrate 20 is attached to the first substrate 10 face-to-back, and the third substrate 30 is attached to the second substrate 20 face-to-face. Therefore, the pad electrode 71 and the pad electrode 47 are joined at the interface between the front surface of the first substrate 10 and the back surface of the second substrate 20. Further, the pad electrode 58 and the pad electrode 64 are joined at the interface between the surface of the second substrate 20 and the surface of the third substrate 30.

Further, the image pickup device of the present disclosure is not limited to the image pickup device that detects the light amount distribution of visible light and acquires it as an image, and acquires the distribution of the incident amount of infrared rays, X-rays, particles, or the like as an image. It may be an image pickup device.

Further, the image pickup apparatus of the present disclosure may be in the form of a module in which an image pickup unit and a signal processing unit or an optical system are packaged together.

According to the image pickup apparatus and the manufacturing method thereof as one embodiment of the present disclosure, a separation portion extending in the thickness direction from the first surface to the second surface of the semiconductor substrate is provided, and the first region portion is provided. And the second region part were physically separated. Therefore, it is possible to avoid unintended and unnecessary irradiation of each of the first region portion and the second region portion. Further, since the charge path portion is provided between the separation portion and the second surface, the output of the first photoelectric conversion unit and the output of the second photoelectric conversion unit can be shared. As a result, phase difference information can be obtained.
It should be noted that the effects described in the present specification are merely examples and are not limited to the description thereof, and other effects may be obtained. In addition, the present technology can have the following configurations.
(1)
A second surface that includes a first surface and a second surface that is located on the opposite side of the first surface in the thickness direction, and is adjacent to the first surface and the second surface along the second surface in an in-plane direction. A semiconductor substrate having one region portion and a second region portion,
A separation portion extending along the thickness direction from the first surface so as to separate the first region portion and the second region portion.
A first photoelectric conversion unit provided in the first region portion and capable of generating a first charge by detecting a first light incident from the first surface and performing photoelectric conversion.
A second photoelectric conversion unit provided in the second region portion and capable of generating a second charge by detecting a second light incident from the first surface and performing photoelectric conversion.
A charge path provided between the separation portion and the second surface at a position overlapping the separation portion in the thickness direction so that the first charge and the second charge can pass through. An image pickup device having an electric charge.
(2)
The image pickup apparatus according to (1) above, wherein the separation portion and the charge path portion are in contact with each other.
(3)
The image pickup apparatus according to (1) or (2) above, further comprising an insulating layer provided between the charge path portion and the wiring layer.
(4)
The image pickup apparatus according to any one of (1) to (3) above, further comprising a peripheral separation portion that integrally surrounds the first region portion and the second region portion.
(5)
A first charge-voltage conversion unit provided in the first region portion, which accumulates the first charge and converts the accumulated first charge into an electric signal and outputs the electric signal.
The above (1), which is provided in the second region portion and further has a second charge-voltage conversion unit that accumulates the second charge and converts the accumulated second charge into an electric signal and outputs the electric signal. The image pickup apparatus according to any one of (4) to (4).
(6)
The semiconductor substrate is a silicon substrate and is a silicon substrate.
The image pickup apparatus according to any one of (1) to (5) above, wherein the charge path portion contains crystalline silicon.
(7)
The semiconductor substrate is a silicon substrate and is a silicon substrate.
The image pickup apparatus according to any one of (1) to (5) above, wherein the charge path portion contains amorphous silicon.
(8)
The image pickup apparatus according to any one of (1) to (7) above, further comprising a wiring layer covering the second surface.
(9)
The image pickup apparatus according to (8) above, wherein the wiring layer includes a thin film transistor.
(10)
A first region portion comprising a first surface and a second surface located opposite the first surface in the thickness direction, the first surface and adjacent first regions along the second surface. And to prepare a semiconductor substrate having a second region portion,
By selectively digging from the second surface of the semiconductor substrate, a first trench separating the first region portion and the second region portion is formed in the semiconductor substrate.
Forming a separation so as to fill the first trench,
Of the separated portions, the upper end portion exposed on the second surface is removed to form a recess.
To form a charge path portion so as to fill the recess,
A first photoelectric that can generate a first charge passing through the charge path portion by detecting a first light incident on the first region portion and performing a photoelectric conversion on the first region portion. A method for manufacturing an image pickup apparatus, which comprises forming a second photoelectric conversion unit capable of generating a second charge passing through the charge path unit by forming the conversion unit.
(11)
A silicon substrate is prepared as the semiconductor substrate, and the silicon substrate is prepared.
The method for manufacturing an image pickup apparatus according to (10) above, wherein the silicon substrate is annealed in a reducing atmosphere and the silicon contained in the silicon substrate is migrated to the recess to form the charge path portion.
(12)
The reducing atmosphere is a hydrogen atmosphere. The method for manufacturing an image pickup apparatus according to (11) above.
(13)
A silicon substrate is prepared as the semiconductor substrate, and the silicon substrate is prepared.
The method for manufacturing an image pickup apparatus according to (10) or (11) above, wherein the charge path portion is formed by forming crystalline silicon in the concave portion by an epitaxial growth method.
(14)
A silicon substrate is prepared as the semiconductor substrate, and the silicon substrate is prepared.
The method for manufacturing an image pickup apparatus according to any one of (10) to (13) above, wherein the charge path portion is formed by forming amorphous silicon in the concave portion by a vapor deposition method.
(15)
The method for manufacturing an image pickup apparatus according to any one of (10) to (14) above, further comprising forming a wiring layer so as to cover the second surface.
(16)
The method for manufacturing an image pickup apparatus according to (15) above, wherein the wiring layer is formed so as to include a thin film transistor.
(17)
The method for manufacturing an image pickup apparatus according to (15) or (16) above, further comprising forming an insulating layer between the charge path portion and the wiring layer.

This application claims priority on the basis of Japanese Patent Application No. 2020-172218 filed on October 12, 2020 at the Japan Patent Office, and this application is made by reference to all the contents of this application. Invite to.

Those skilled in the art may conceive various modifications, combinations, sub-combinations, and changes, depending on design requirements and other factors, which are included in the claims and their equivalents. It is understood that it is a person skilled in the art.

Claims (17)

1. A second surface that includes a first surface and a second surface that is located on the opposite side of the first surface in the thickness direction, and is adjacent to the first surface and the second surface along the second surface in an in-plane direction. A semiconductor substrate having one region portion and a second region portion,
   A separation portion extending along the thickness direction from the first surface so as to separate the first region portion and the second region portion.
   A first photoelectric conversion unit provided in the first region portion and capable of generating a first charge by detecting a first light incident from the first surface and performing photoelectric conversion.
   A second photoelectric conversion unit provided in the second region portion and capable of generating a second charge by detecting a second light incident from the first surface and performing photoelectric conversion.
   A charge path provided between the separation portion and the second surface at a position overlapping the separation portion in the thickness direction so that the first charge and the second charge can pass through. An image pickup device having an electric charge.
2. The image pickup apparatus according to claim 1, wherein the separation unit and the charge path unit are in contact with each other.
3. The wiring layer covering the second surface and
   The image pickup apparatus according to claim 1, further comprising an insulating layer provided between the charge path portion and the wiring layer.
4. The imaging apparatus according to claim 1, further comprising a peripheral separation portion that integrally surrounds the first region portion and the second region portion.
5. A first charge-voltage conversion unit provided in the first region portion, which accumulates the first charge and converts the accumulated first charge into an electric signal and outputs the electric signal.
   Claim 1 further includes a second charge-voltage conversion unit provided in the second region portion, which accumulates the second charge and converts the accumulated second charge into an electric signal and outputs the electric signal. The imaging device described.
6. The semiconductor substrate is a silicon substrate and is a silicon substrate.
   The image pickup apparatus according to claim 1, wherein the charge path portion includes crystalline silicon.
7. The semiconductor substrate is a silicon substrate and is a silicon substrate.
   The image pickup apparatus according to claim 1, wherein the charge path portion contains amorphous silicon.
8. The image pickup apparatus according to claim 1, further comprising a wiring layer covering the second surface.
9. The image pickup apparatus according to claim 8, wherein the wiring layer includes a thin film transistor.
10. A first region portion comprising a first surface and a second surface located opposite the first surface in the thickness direction, the first surface and adjacent first regions along the second surface. And to prepare a semiconductor substrate having a second region portion,
    By selectively digging from the second surface of the semiconductor substrate, a first trench separating the first region portion and the second region portion is formed in the semiconductor substrate.
    Forming a separation so as to fill the first trench,
    Of the separated portions, the upper end portion exposed on the second surface is removed to form a recess.
    To form a charge path portion so as to fill the recess,
    A first photoelectric that can generate a first charge passing through the charge path portion by detecting a first light incident on the first region portion and performing a photoelectric conversion on the first region portion. A method for manufacturing an image pickup apparatus, which comprises forming a second photoelectric conversion unit capable of generating a second charge passing through the charge path unit by forming the conversion unit.
11. A silicon substrate is prepared as the semiconductor substrate, and the silicon substrate is prepared.
    The method for manufacturing an image pickup apparatus according to claim 10, wherein the silicon substrate is annealed in a reducing atmosphere and the silicon contained in the silicon substrate is migrated to the recess to form the charge path portion.
12. The method for manufacturing an image pickup apparatus according to claim 11, wherein the reducing atmosphere is a hydrogen atmosphere.
13. A silicon substrate is prepared as the semiconductor substrate, and the silicon substrate is prepared.
    The method for manufacturing an image pickup apparatus according to claim 10, wherein the charge path portion is formed by forming crystalline silicon in the concave portion by an epitaxial growth method.
14. A silicon substrate is prepared as the semiconductor substrate, and the silicon substrate is prepared.
    The method for manufacturing an image pickup apparatus according to claim 10, wherein the charge path portion is formed by forming amorphous silicon in the concave portion by a vapor deposition method.
15. The method for manufacturing an image pickup apparatus according to claim 10, further comprising forming a wiring layer so as to cover the second surface.
16. The method for manufacturing an image pickup apparatus according to claim 15, wherein the wiring layer is formed so as to include a thin film transistor.
17. The method for manufacturing an image pickup apparatus according to claim 15, further comprising forming an insulating layer between the charge path portion and the wiring layer.

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