Light detection device and electronic device

Abstract

The present disclosure relates to a photoelectric detector capable of suppressing breakage and an electronic apparatus. The light detector has a pixel array section in which a plurality of pixels are arranged in a row direction and a column direction on a semiconductor substrate. The pixel array section has a pixel inter-isolation section provided between the pixels. The pixel inter-isolation section has a first intersection section and a second intersection section in a plan view, and a linear section between the first intersection section and the second intersection section. The first intersection section and the second intersection section have a trench structure in a cross section that separates the semiconductor substrate from a first surface of the semiconductor substrate to a second surface on an opposite side thereof. The linear section has a semiconductor region and the trench structure as a part of the cross section of the semiconductor substrate. For example, the present disclosure can be applied to an imaging apparatus that generates and outputs an imaging signal corresponding to an amount of incident light.

Description

Technical Field

[0001] This invention relates to optical detection devices and electronic devices, and particularly to optical detection devices and electronic devices that minimize breakage. Background Technology

[0002] In the prior art, there are solid-state imaging devices in which trenches are formed at the pixel boundaries to penetrate the semiconductor substrate, thereby completely isolating the photoelectric conversion portion of the pixel in order to suppress color mixing and ensure the saturation charge Qs during pixel miniaturization (see, for example, Patent Document 1).

[0003] Reference List

[0004] Patent documents

[0005] Patent document 1: Japanese Patent Application Publication No. 2018-148116 Summary of the Invention

[0006] The problem to be solved by the present invention

[0007] An insulating film or metal material is embedded at the boundaries of the completely isolated pixels. There is a possibility that cracks may occur at the pixel boundaries due to warping that occurs during the manufacturing process and various stresses applied during processing.

[0008] This disclosure is made in light of these circumstances, and is intended to minimize disruption.

[0009] Solution to the problem

[0010] The light detection device of the first aspect of the present invention includes: A pixel array unit, wherein multiple pixels are arranged on a semiconductor substrate along row and column directions, wherein Pixel array units have inter-pixel isolation portions between pixels. In the planar view, the inter-pixel isolation portion has a first intersection, a second intersection, and a straight portion located between the first intersection and the second intersection. In the cross-sectional view, both the first and second intersections have trench structures that isolate the semiconductor substrate from its first surface to its second surface, with the second surface disposed on the opposite side of the first surface. In the cross-sectional view, the vertical portion has a semiconductor region and a trench structure that are part of a semiconductor substrate.

[0011] The electronic equipment according to the second aspect of this disclosure includes: The optical detection device includes: A pixel array unit, wherein multiple pixels are arranged along row and column directions on a semiconductor substrate, wherein... The pixel array unit has inter-pixel isolation portions disposed between the pixels. In the planar view, the inter-pixel isolation portion has a first intersection, a second intersection, and a straight portion located between the first intersection and the second intersection. In the cross-sectional view, both the first and second intersections have trench structures that isolate the semiconductor substrate from its first surface to its second surface, with the second surface disposed on the opposite side of the first surface. In the cross-sectional view, the vertical portion has a semiconductor region and a trench structure that are part of a semiconductor substrate.

[0012] In the first and second aspects of this disclosure, a pixel array unit is provided on a semiconductor substrate, wherein a plurality of pixels are arranged in a row direction and a column direction, and an inter-pixel isolation portion is provided between the pixels in the pixel array unit. The inter-pixel isolation portion includes a first intersection portion, a second intersection portion, and a straight portion located between the first intersection portion and the second intersection portion. In a plan view, both the first intersection portion and the second intersection portion have a trench structure that isolates the semiconductor substrate from a first surface to a second surface of the semiconductor substrate. In a cross-sectional view, the second surface is disposed on the opposite side of the first surface, and in the cross-sectional view, the straight portion includes a semiconductor region as part of the semiconductor substrate and the trench structure.

[0013] The optical detection device and electronic equipment can be standalone devices or modules integrated into another device. Attached Figure Description

[0014] Figure 1 This is a schematic diagram illustrating a configuration of a light detection device that applies the technology disclosed herein.

[0015] Figure 2 This is a simplified diagram showing the equivalent circuit of a pixel.

[0016] Figure 3 This is a cross-sectional view showing a first configuration example of pixels.

[0017] Figure 4 This is a plan view showing a first configuration example of pixels.

[0018] Figure 5 It is a diagram illustrating a method for manufacturing pixels according to a first configuration example.

[0019] Figure 6 This is a diagram illustrating a method for manufacturing pixels according to a first configuration example.

[0020] Figure 7 This is a diagram illustrating a method for manufacturing pixels according to a first configuration example.

[0021] Figure 8 This is a diagram illustrating a method for manufacturing pixels according to a first configuration example.

[0022] Figure 9 This is a diagram illustrating a method for manufacturing pixels according to a first configuration example.

[0023] Figure 10 This is a diagram illustrating a method for manufacturing pixels according to a first configuration example.

[0024] Figure 11 This is a diagram illustrating a method for manufacturing pixels according to a first configuration example.

[0025] Figure 12 This is a diagram illustrating a method for manufacturing pixels according to a first configuration example.

[0026] Figure 13 This is a diagram illustrating a method for manufacturing pixels according to a first configuration example.

[0027] Figure 14 This is a cross-sectional view showing a first variant of the pixels according to the first configuration example.

[0028] Figure 15 This is a cross-sectional view showing a second variant of the pixels according to the first configuration example.

[0029] Figure 16 This is a plan view showing a third variation of the pixels according to the first configuration example.

[0030] Figure 17 This is a diagram illustrating the operational effect of the inter-pixel isolation section.

[0031] Figure 18 This is a cross-sectional view showing a second configuration example of pixels.

[0032] Figure 19 This is a plan view showing a second configuration example of pixels.

[0033] Figure 20 This is a cross-sectional view showing a third configuration example of pixels.

[0034] Figure 21 This is a cross-sectional view showing a first variant of the pixels according to the third configuration example.

[0035] Figure 22 This is a cross-sectional view showing a second variant of the pixels according to the third configuration example.

[0036] Figure 23 This is a cross-sectional view showing a third variation of the pixels according to the third configuration example.

[0037] Figure 24 This is a cross-sectional view showing a fourth variation of the pixels according to the third configuration example.

[0038] Figure 25 This is a diagram illustrating a method for manufacturing pixels according to a third configuration example.

[0039] Figure 26 This is a diagram illustrating a method for manufacturing pixels according to a third configuration example.

[0040] Figure 27 This is a diagram illustrating a method for manufacturing pixels according to a third configuration example.

[0041] Figure 28 This is a block diagram illustrating an example configuration of an electronic device.

[0042] Figure 29 This is a diagram used to illustrate an example of the use of an image sensor.

[0043] Figure 30 This is a diagram illustrating a schematic structure of an endoscopic surgical system.

[0044] Figure 31 This is a block diagram illustrating an example of the functional configuration of the camera and CCU.

[0045] Figure 32 This is a block diagram illustrating an example of the general structure of a vehicle control system.

[0046] Figure 33 This is an explanatory diagram showing an example of the placement of the vehicle exterior information detection unit and the imaging unit. Detailed Implementation

[0047] In the following description, modes for implementing the technology of this disclosure (hereinafter referred to as embodiments) will be described with reference to the accompanying drawings. The description will be given in the following order.

[0048] 1. Schematic configuration example of a light detection device

[0049] 2. Equivalent circuit of a pixel

[0050] 3. Example of the first configuration of pixels

[0051] 4. A method for manufacturing pixels according to a first configuration example

[0052] 5. Variations of the first configuration example

[0053] 6. Operational effect of the inter-pixel isolation section of this disclosure

[0054] 7. Example of a second configuration for pixels

[0055] 8. Example of a third configuration for pixels

[0056] 9. Variations of the third configuration example

[0057] 10. A method for manufacturing pixels according to the third configuration example

[0058] 11. Configuration examples of electronic devices

[0059] 12. Examples of Image Sensor Applications

[0060] 13. Examples of the application of endoscopic surgical systems

[0061] 14. Examples of applications of moving bodies

[0062] Note that in this specification and the accompanying drawings, identical or similar parts are indicated by identical or similar reference numerals, and redundant descriptions will be omitted as appropriate. The drawings are schematic, and the relationships between thickness and planar dimensions, the thickness ratios of each layer, etc., may differ from actual relationships and scales. Furthermore, the drawings may include parts with different dimensional relationships or ratios in some cases.

[0063] Furthermore, the definitions of directions such as up and down in the following description are merely for ease of description and do not limit the technical concept of this disclosure. For example, if the target is rotated 90° and observed, up and down are interpreted by replacing them with left and right, and if the target is rotated 180° and observed, up and down are interpreted by reversing them.

[0064] The technology disclosed herein can be applied to a light detection device comprising a pixel array unit in which pixels are arranged in a matrix in a two-dimensional manner, photoelectrically converting incident light and outputting a pixel signal according to the amount of light. The light to be detected can be light in the visible light region including wavelengths of red (R), green (G), and blue (B), or it can be light in the invisible light region such as infrared light. Alternatively, light from both the visible and invisible light regions can be used. The light detection device can be used as an imaging device that generates and outputs an imaging signal corresponding to the amount of incident light, or as a light receiving device (distance measurement sensor) of a distance measurement system that receives infrared light emitted as active light reflected by an object (reflected light) and measures the distance to the object using methods such as direct ToF or indirect ToF.

[0065] <1. Illustrative Configuration Example of an Optical Detection Device>

[0066] Figure 1 This is a schematic diagram illustrating a configuration of a light detection device that applies the technology disclosed herein.

[0067] Figure 1The light detection device 1 includes a pixel array unit 3 and surrounding peripheral circuit units. In the pixel array unit 3, multiple pixels 2 are arranged along the row and column directions on a semiconductor substrate 21, which uses silicon (Si) as the semiconductor. The peripheral circuit units include a vertical drive circuit 4, a column signal processing circuit 5, a horizontal drive circuit 6, an output circuit 7, a control circuit 8, etc.

[0068] Pixel 2 includes a photodiode as a photoelectric conversion unit and multiple pixel transistors. For example, the multiple pixel transistors include four transistors comprising a transmission transistor, a selection transistor, a reset transistor, and an amplification transistor, and each includes a MOS transistor (MOSFET).

[0069] Pixel 2 may have a shared pixel structure. This shared pixel structure includes multiple photodiodes, multiple transmission transistors, a shared floating diffuser, and one of each of the other shared pixel transistors. That is, in the shared pixel structure, the photodiodes and transmission transistors are disposed in each pixel 2, and the other pixel transistors are shared and used by multiple pixels 2.

[0070] The control circuit 8 receives data such as the input clock and indication of the operating mode, and outputs data such as internal information of the light detection device 1. Specifically, the control circuit 8 generates clock signals and control signals based on the vertical synchronization signal, horizontal synchronization signal, and master clock, which serve as references for the operation of the vertical drive circuit 4, column signal processing circuit 5, horizontal drive circuit 6, etc. Then, the control circuit 8 outputs the generated clock signals and control signals to the vertical drive circuit 4, column signal processing circuit 5, horizontal drive circuit 6, etc.

[0071] The vertical driving circuit 4 includes, for example, a shift register, selects a predetermined pixel driving line 10, provides pulses for driving the pixel 2 to the selected pixel driving line 10, and drives the pixel 2 row by row. That is, the vertical driving circuit 4 sequentially and selectively scans each pixel 2 of the pixel array unit 3 in the vertical direction row by row, and provides a signal based on the signal charge generated according to the amount of light received in the photoelectric conversion section of each pixel 2 to the column signal processing circuit 5 via the vertical signal line 9.

[0072] The column signal processing circuit 5 is configured for each column of pixel 2 and performs signal processing such as noise removal for each pixel column on the signal output from pixel 2 in a row. For example, the column signal processing circuit 5 performs signal processing such as correlated double sampling (CDS) and analog-to-digital (AD) conversion for removing pixel-specific fixed-pattern noise.

[0073] The horizontal drive circuit 6 includes, for example, a shift register, which sequentially selects each column signal processing circuit 5 by outputting horizontal scan pulses in sequence, and outputs pixel signals from each column signal processing circuit 5 to the horizontal signal line 11.

[0074] Output circuit 7 processes the signals sequentially supplied from column signal processing circuit 5 via horizontal signal line 11 and outputs the processed signals. For example, output circuit 7 may perform only buffering, or it may perform black level adjustment, column change correction, various types of digital signal processing, etc. Input / output terminals 13 exchange signals with external devices.

[0075] The light detection device 1 configured as described above has a structure called the column AD method, wherein a column signal processing circuit 5 is provided for each column to perform CDS processing and AD conversion processing. The light detection device 1 generates a signal corresponding to the amount of light received by each pixel 2 of the pixel array 3 and outputs the signal to the outside. The light detection device 1 can be used as, for example, a solid-state imaging device that detects the distribution of incident light amount of infrared or visible light and uses this distribution to form an image, or as a light receiving device for a distance measurement system that receives light reflected from an object as active light emission (reflected light) and measures the distance to the object using a direct ToF method or an indirect ToF method.

[0076] <2. Equivalent Circuit of a Pixel>

[0077] Figure 2 The equivalent circuit of pixel 2 is shown.

[0078] Pixel 2 includes, for example, a photodiode PD as a photoelectric conversion unit, a transfer transistor TG electrically connected to the photodiode PD, and a floating diffuser FD electrically connected to the transfer transistor TG. Furthermore, pixel 2 includes a reset transistor RST, an amplification transistor AMP, and a selection transistor SEL. The transfer transistor TG, reset transistor RST, amplification transistor AMP, and selection transistor SEL are, for example, n-type MOS transistors (MOSFETs).

[0079] A photodiode (PD) photoelectrically converts incident light and generates a charge (signal charge) corresponding to the amount of incident light received. In a photodiode (PD), the cathode is electrically connected to the source of the transmission transistor (TG), and the anode is electrically connected to a reference potential line (e.g., ground).

[0080] The transfer transistor TG controls the transfer of charge generated by the photodiode PD. When the transfer transistor TG is turned on, it transfers the charge generated by the photodiode PD to the floating diffuser FD. In the transfer transistor TG, the drain is electrically connected to the floating diffuser FD, and the gate is electrically connected to the pixel drive wiring. This pixel drive wiring is... Figure 1This is part of the pixel-driven wiring 10 described in the document.

[0081] The floating diffuser (FD) is a charge accumulation section that temporarily accumulates the charge transferred from the photodiode (PD), and it is also a charge-to-voltage converter that generates a voltage corresponding to the amount of charge. The floating diffuser (FD) is electrically connected to the gate of the amplifying transistor (AMP) and the source of the reset transistor (RST).

[0082] The reset transistor RST resets the potential of the floating diffuser FD to a predetermined potential. When the reset transistor RST is turned on via the pixel drive wiring provided to the gate, it resets the potential of the floating diffuser FD to the potential of the power supply line VDD. This pixel drive wiring is... Figure 1 This is part of the pixel drive wiring 10 described herein. When the potential of the floating diffusion FD is reset, the reset transistor RST is also simultaneously turned on.

[0083] The amplifying transistor AMP generates a voltage signal corresponding to the level of charge accumulated in the floating diffusion FD, which serves as the pixel signal. The amplifying transistor AMP is connected in series with the select transistor SEL and is connected to the vertical signal line 9 via the select transistor SEL. The amplifying transistor AMP, together with the load circuit in the column signal processing circuit 5 connected to the vertical signal line 9, forms a source follower. When the select transistor SEL is turned on, the amplifying transistor AMP outputs the voltage of the floating diffusion FD to the column signal processing circuit 5 via the vertical signal line 9. The drain of the amplifying transistor AMP is connected to the power supply line VDD, and the source of the amplifying transistor AMP is connected to the drain of the select transistor SEL.

[0084] The select transistor SEL controls the timing of the pixel signal output. The source of the select transistor SEL is connected to vertical signal line 9, and the gate of the select transistor SEL is connected to the pixel drive line. When the select transistor SEL is turned on through the pixel drive line provided to its gate, the select transistor SEL outputs the pixel signal from the amplifying transistor AMP to vertical signal line 9. This pixel drive wiring is... Figure 1 This is part of the pixel-driven wiring 10 described in the document.

[0085] The select transistor SEL can be positioned between the power supply line VDD and the amplifying transistor AMP. In this case, the drain of the reset transistor RST is electrically connected to both the power supply line VDD and the drain of the select transistor SEL. The source of the select transistor SEL is electrically connected to the drain of the amplifying transistor AMP. The source of the amplifying transistor AMP (the output terminal of pixel 2) is electrically connected to the vertical signal line 9, and the gate of the amplifying transistor AMP is electrically connected to the source of the reset transistor RST.

[0086] As described above, the pixel 2 is photoelectrically converted into incident light under the control of the vertical drive circuit 4, and the pixel signal corresponding to the amount of received light is output to the column signal processing circuit 5 via the vertical signal line 9.

[0087] <3. Example of the first configuration of pixels>

[0088] See Figure 3 and Figure 4 This section describes a first configuration example of pixel 2 in the light detection device 1.

[0089] Figure 3 This is a cross-sectional view showing a first configuration example of pixel 2 in the light detection device 1. Figure 4 This is a plan view representing the first configuration example of pixel 2. Figure 3 It shows along Figure 4 The cross-sectional view taken along line X-X' and the cross-sectional view taken along line Y-Y', and Figure 4 It shows along Figure 3 The planar view is intercepted by line Z-Z'. Line X-X' is the line that passes through the corner of pixel 2, which has a rectangular pixel area, and line Y-Y' is the line that intersects the center of the pixel area in the horizontal or vertical direction.

[0090] like Figure 3 As shown, pixel 2 includes, for example, a semiconductor substrate (silicon substrate) 21 using silicon (Si) as the semiconductor and a wiring layer 22 formed on a first surface FA of the semiconductor substrate 21. Figure 3 The first surface FA of the semiconductor substrate 21 of the lower middle wiring layer 22 is the front side of the semiconductor substrate 21, located at... Figure 3 The second surface SA of the upper middle semiconductor substrate 21 is the back side of the semiconductor substrate 21 and is the light receiving surface (light incident surface) for light incidence. Therefore, the light detection device 1 containing the pixel 2 is a back-illuminated light detection device that receives light from the back side of the semiconductor substrate 21. Note that the logic substrate on which the logic circuit is formed is bonded to the underside of the wiring layer 22, but is omitted in the figure.

[0091] A fixed charge film 23, an insulating film 24, a color filter 25, an inter-pixel light-shielding film 26, and an on-chip lens (OCL) 27 are formed on the second surface SA side of the semiconductor substrate 21, which serves as the light-receiving surface side.

[0092] The semiconductor substrate 21 comprises, for example, silicon (Si) and is formed to have a thickness of, for example, 2 μm to 15 μm. In the semiconductor substrate 21, for example, an N-type (second conductivity type) semiconductor region 42 (hereinafter referred to as N-type semiconductor region 42) is formed in a P-type (first conductivity type) semiconductor region 41 (hereinafter referred to as P-type semiconductor region 41) for each pixel 2, such that a photodiode PD is formed on a pixel-by-pixel basis. The N-type semiconductor region 42 serves as a charge accumulation region for the photodiode PD. The P-type semiconductor regions 41 disposed on the front and rear surfaces of the semiconductor substrate 21 also serve as hole charge accumulation regions for suppressing dark current.

[0093] Inter-pixel isolation portions 43 are formed between pixels 2 on the semiconductor substrate 21 to isolate the photodiodes PD of each pixel 2. The inter-pixel isolation portions 43 include a fixed charge film 44, an insulating film 45, and an air gap (air layer) 46 formed at the center of the inner side of the insulating film 45, all formed on the side surface, etc. A P-type semiconductor region 47 is formed between the inter-pixel isolation portions 43 and the photodiodes PD in the planar direction (lateral direction). The fixed charge film 44 is formed using a high dielectric material with a negative fixed charge and suppresses the generation of dark current. The P-type semiconductor region 47 enhances the electrical isolation between pixels. The impurity concentration of the P-type semiconductor region 47 is higher than that of the P-type semiconductor region 41, which is a substrate region, but it can have the same impurity concentration as the P-type semiconductor region 41. The insulating film 45 can be made of, for example, SiO2 or a composite material with SiO2 as the main component (SiON, SiOC, etc.). Materials used as the fixed charge film 44 include, for example, hafnium oxide (HfO2), zirconium dioxide (ZrO2), tantalum oxide (Ta2O5), etc.

[0094] In the straight portion of the inter-pixel isolation portion 43 corresponding to the side of the rectangular pixel region, as shown in the cross-sectional view along line Y-Y', a shallow trench isolation (STI) 48 is formed on the first surface FA side of the semiconductor substrate 21, and a P-type semiconductor region 47 is formed on the second surface SA side. On the other hand, in the intersection of the inter-pixel isolation portion 43 corresponding to the corner of the rectangular pixel region, as shown in the cross-sectional view along line X-X', the STI 48 is formed on the first surface FA side of the semiconductor substrate 21, but the P-type semiconductor region 47 is not formed on the second surface SA side. On the second surface SA side of the intersection of the inter-pixel isolation portions 43, the insulating film 45 of the inter-pixel isolation portion 43 and the insulating film 24 formed on the second surface SA are connected. Furthermore, the fixed charge film 44 formed on the side surface of the inter-pixel isolation portion 43 and the fixed charge film 23 formed on the second surface SA are also connected. In the straight section of the inter-pixel isolation portion 43 shown in the cross-sectional view along line Y-Y', a fixed charge film 44 is formed on the side surface, top surface, and bottom surface of the trench between the STI 48 on the first surface FA side and the P-type semiconductor region 47 on the second surface SA side. In the straight section of the inter-pixel insulation portion 43, the P-type semiconductor region 47, which is part of the semiconductor substrate 21, exists between the insulating film 24 and the fixed charge film 23 formed on the second surface SA and the insulating film 45 and the fixed charge film 44 of the inter-pixel insulation portion 43 in the substrate.

[0095] In other words, the intersection of the inter-pixel insulating portion 43 has a structure in which a fixed charge film 44, an insulating film 45, an air gap 46, and an STI 48 are embedded in a trench structure that completely isolates the semiconductor substrate 21 by penetrating from the first surface FA to the second surface SA. The straight portion has a P-type semiconductor region 47 on the second surface SA side, which is a portion of the semiconductor substrate 21 that is not penetrated and is retained. The trench structure, in which the fixed charge film 44, the insulating film 45, the air gap 46, and the STI 48 are embedded, is also described. The trench structure can also be referred to as a trench, a recess, a hole, etc.

[0096] like Figure 4As shown in the plan view, the inter-pixel isolation portion 43, arranged in a grid pattern along the boundary of pixel 2 (represented by dotted lines), has multiple intersections 43A and straight portions 43B positioned between two adjacent intersections 43A, such as a first intersection 43A1 and a second intersection 43A2. At the intersections 43A, the semiconductor substrate 21 is isolated across the entire substrate thickness by a trench structure, and a fixed charge film 44, an insulating film 45, etc., are embedded in the trench structure. On the other hand, in the straight portions 43B, a portion of the semiconductor substrate 21 remains connected through a P-type semiconductor region 47, and the trench is configured not to penetrate the semiconductor substrate 21. Regarding the intersections 43A, all intersections 43A of the pixel array unit 3 may have a structure in which the fixed charge film 44, the insulating film 45, etc., are embedded in a trench structure that penetrates the semiconductor substrate 21 to completely isolate the semiconductor substrate 21, or only a plurality of intersections 43A at predetermined positions of the pixel array unit 3 may have such an isolation structure.

[0097] like Figure 3 As shown in the cross-sectional view, the wiring layer 22 formed on the first surface FA side of the semiconductor substrate 21 includes metal wiring 51 disposed in multiple layers and insulating films (interlayer insulating films) 52 formed between these layers. Each metal wiring 51 is formed using a metal material such as Al, Ag, Au, Cu, Pt, Mo, Cr, Ti, Ni, W, or Fe, or an alloy material containing these metals, as a metal film. For example, by using via plugs such as W or Cu, the metal wiring 51 of each layer is connected to another metal wiring 51 of the upper and lower layers at predetermined locations. The insulating film 52 is composed of, for example, a SiO2 film, a Low-k film (low dielectric constant insulating film), a SiOC film, etc. In the wiring layer 22, a plurality of pixel transistors Tr are formed, which include a transfer transistor TG for reading out the charge, etc., accumulated in the photodiode PD.

[0098] The fixed charge film 23 formed on the second surface SA, which is the back side of the semiconductor substrate 21, is a film with a negative fixed charge, similar to the fixed charge film 44, and suppresses the generation of dark current. As described later, the fixed charge film 23 on the second surface SA and the fixed charge film 44 of the inter-pixel isolation portion 43 are formed together in the same process. The insulating film 24 formed on the fixed charge film 23 is also formed together with the insulating film 45 of the inter-pixel isolation portion 43 in the same process.

[0099] Color filter 25 transmits light of a predetermined wavelength (e.g., red (R), green (G), or blue (B)) incident through on-chip lens 27, and directs the light onto photodiode PD. Color filter 25 is formed, for example, by spin-coating a photosensitive resin containing colorants such as pigments or dyes. The red, green, and blue colors are arranged in each pixel using, for example, a Bayer pattern, but can be arranged using other methods. For example, an RGBW color filter array with W added to R, G, and B can also be used. The W color filter is a color filter that transmits light of all R, G, and B colors (wavelengths) and can be referred to as C (transparent). For example, color filters for complementary colors such as yellow (Y), cyan (Cy), and magenta (Mg) can be provided.

[0100] The inter-pixel light-shielding film 26 is used to prevent light from leaking to adjacent pixels 2. The inter-pixel light-shielding film 26 may be a single-layer metal film of titanium (Ti), titanium nitride (TiN), tungsten (W), aluminum (Al), or tungsten nitride (WN). Alternatively, a laminate of these metals (e.g., a laminate of titanium and tungsten, a laminate of titanium nitride and tungsten, etc.) may also be used as the inter-pixel light-shielding film 26.

[0101] An on-chip lens 27 is formed on the color filter 25 for each pixel 2. The on-chip lens 27 comprises a resin-based material, such as styrene-based resin, acrylic resin, styrene-acrylic copolymer resin, siloxane resin, etc. The on-chip lens 27 converges the incident light, and the converged light effectively enters the photodiode PD via the color filter 25.

[0102] As described above, the pixel array section 3 of the light detection device 1 has an inter-pixel isolation section 43 at the boundary of each pixel 2. The inter-pixel isolation section 43 has a structure in which the semiconductor substrate 21 is completely isolated at the intersection corresponding to the corner of the pixel region, and a structure in which a portion of the semiconductor substrate 21 is held connected at the vertical portion by a P-type semiconductor region 47 near the second surface SA. Therefore, compared to an inter-pixel isolation section structure where all pixel boundaries are completely isolated, cracking can be minimized. Reference will be made later. Figure 17 Describe the effect of the inter-pixel isolation section 43 in minimizing breakage.

[0103] <4. Method for manufacturing pixels according to the first configuration example>

[0104] Reference Figures 5 to 13 A method for manufacturing pixel 2 according to the first configuration example described above is described.

[0105] First, such as Figure 5As shown, with the first surface FA, which is the front surface of the semiconductor substrate 21, facing upwards, N-type impurities such as phosphorus (P) and arsenic (As) are ion-implanted into each pixel region of the semiconductor substrate 21, including the P-type semiconductor region 41, to form an N-type semiconductor region 42, thereby forming a photodiode PD for each pixel unit. Next, the semiconductor substrate 21 is etched from the first surface FA side to a predetermined depth by dry etching, and a trench 101 is formed at the boundary of the pixel 2. The trench 101 is formed in a lattice shape in the planar view. By comparing the depth of the trench 101 in the X-X' line cross-sectional view and the Y-Y' line cross-sectional view, it can be seen that the trench 101 is formed such that the intersection is deeper than the straight portion of the inter-pixel isolation portion 43. For example, as Figure 6 As shown, the opening width of the mask in dry etching is wider at the intersection than at the straight portion, resulting in a deeper trench 101 at the intersection than at the straight portion due to the micro-load effect. An STI48 is formed around the trench 101 on the first surface FA of the semiconductor substrate 21. The STI48 can be formed after or before the trench 101 is formed.

[0106] Next, as Figure 7 As shown, P-type impurity ions, such as boron (B) and gallium (Ga), are implanted into the side and bottom surfaces of the trench 101, forming a P-type semiconductor region 47 at a predetermined depth from the side and bottom surfaces of the trench 101. For example, the P-type semiconductor region 47 is formed with an impurity concentration higher than that of the P-type semiconductor region 41, which serves as the substrate region. Then, a filling material 111 is embedded in the trench 101, and an STI 48 is formed near the interface on the first surface FA side, using the STI 48 to seal the first surface FA side of the trench 101. Therefore, on the first surface FA side of the semiconductor substrate 21, the STI 48 on both sides of the inter-pixel insulating portion 43 is integrated. Figures 7 to 10 In the Z-Z' line plan view, the embedded material 111, which is formed deeper than STI 48, is also shown in an overlay manner to illustrate the arrangement of the embedded material 111. For example, a single-layer film or laminated film of SiO2, SiN, polycrystalline silicon, etc. can be used for the embedded material 111.

[0107] Next, as Figure 8 As shown, after a pixel transistor Tr, such as a transmission transistor TG, is formed on the interface of the first surface FA of the semiconductor substrate 21, a wiring layer 22 is formed, which includes metal wiring 51 disposed in multiple layers and an insulating film 52 disposed therebetween. The wiring layer 22 is formed by sequentially stacking an insulating film 52, such as a silicon oxide film, and metal wiring 51 formed using aluminum, copper, etc., and electrically connecting the metal wiring 51 of each layer through vias or plugs as needed.

[0108] Next, as Figure 9 As shown, the entire semiconductor substrate 21 on which the wiring layer 22 is formed is inverted, and a logic substrate manufactured in a separate process is bonded to the wiring layer 22 by means of plasma bonding or the like. Then, from the upper surface (second surface SA) side of the semiconductor substrate 21, the semiconductor substrate 21 is thinned to a desired thickness using, for example, wet etching, dry etching, CMP, or the like. The thickness of the semiconductor substrate 21 varies depending on the target wavelength of the incident light, assumed to be . For example, if the target wavelength is only a wavelength in the visible light region, the thickness of the semiconductor substrate 21 is expected to be in the range of 2 μm to 6 μm. Alternatively, if the target wavelength also includes wavelengths in the near-infrared region, the thickness of the semiconductor substrate 21 is expected to be in the range of, for example, 3 to 15 μm.

[0109] Next, as Figure 10 As shown, the second surface SA side of the semiconductor substrate 21 is further removed by methods such as wet etching, dry etching, and CMP. Therefore, the thickness of the semiconductor substrate 21 becomes such that the embedded material 111 protrudes at the intersection of the inter-pixel isolation portion 43 and is not exposed at the straight portion.

[0110] Next, as Figure 11 As shown, the embedded material 111 in the trench 101 of the inter-pixel isolation portion 43 is removed, and a cavity 121 is formed. The embedded material 111 in the trench 101 can be removed, for example, by wet etching or isotropic dry etching. The cavity 121 communicates with the back side of the semiconductor substrate 21 at the intersection of the inter-pixel isolation portions 43, and is closed by the P-type semiconductor region 47 at the straight portion. In the Z-Z' line plan view, the cavity 121, which is formed deeper than the P-type semiconductor region 47, is also shown in an overlapping manner for the straight portion of the inter-pixel isolation portion 43.

[0111] Next, as Figure 12 As shown, a fixed charge film 23 is formed on the upper surface of the second surface SA of the semiconductor substrate 21, and a fixed charge film 44 is formed on the side surface and bottom surface of the cavity 121. Subsequently, an insulating film 24 on the upper surface of the fixed charge film 44 on the second surface SA of the semiconductor substrate 21 and an insulating film 45 inside the fixed charge film 44 in the cavity 121 are formed together. When the insulating film 24 is formed to a predetermined thickness, the area where the insulating film 24 is not formed remains within the cavity 121, such as... Figure 12As shown, an air gap 46 is formed. An insulating film 24 may be embedded throughout the entire interior of the fixed charge film 44 in cavity 121, and in this case, the air gap 46 is not formed. For the methods of forming the fixed charge films 23 and 44 and the insulating films 24 and 45, for example, CVD, sputtering, or atomic layer deposition (hereinafter, ALD) can be used. For the straight portion of the inter-pixel insulating portion 43 where the second surface SA side is closed by the P-type semiconductor region 47, the fixed charge film 44 is formed on the upper surface other than the side and bottom surfaces of cavity 121. For example, hafnium oxide (HfO2), aluminum oxide (Al2O3), zirconium dioxide (ZrO2), tantalum oxide (Ta2O5), etc., can be used as materials for the fixed charge film 44. For example, SiO2, or composite materials with SiO2 as the main component (SiON, SiOC, etc.), can be used as materials for the insulating film 45.

[0112] Subsequently, as Figure 13 As shown, after forming an inter-pixel light-shielding film 26 and a color filter 25 on the upper surface of the insulating film 24 above the second surface SA of the semiconductor substrate 21, an on-chip lens 27 is formed for each pixel 2, thereby completing the process. Figure 3 The structure of pixel 2 is shown. The inter-pixel light-shielding film 26 is formed together with the light-shielding film of the OPB pixel formed outside the effective pixel area. The OPB pixel is a pixel used to detect the black level reference signal, and the entire pixel area on the second surface SA side of the semiconductor substrate 21 is covered by the light-shielding film.

[0113] It can be manufactured according to the method described above. Figure 3 Pixel 2 of the first configuration example shown.

[0114] <5. Variations of the First Configuration Example>

[0115] A variation of pixel 2 based on the first configuration example described above will be described below. References will be made to this example in the following text. Figure 3 The structure of pixel 2 described is called the basic structure.

[0116] (First variation)

[0117] Figure 14 This is a cross-sectional view showing the first deformed example of pixel 2. When viewed in a plan view, along... Figure 14 The cross-sectional view taken by line X-X' and along Figure 4 The position of the cross-sectional image intercepted by line Y-Y' in the image corresponds to the position of the inter-pixel isolation portion 43. Figure 4 The intersection and straight section of lines X-X' and Y-Y'.

[0118] exist Figure 14In the pixel 2 according to the first variation shown, an anti-reflection portion 211 for suppressing the reflection of incident light is further formed on the second surface SA of the semiconductor substrate 21. Apart from forming the anti-reflection portion 211, the pixel 2 according to the first variation is similar to... Figure 3 The basic structure shown is as follows. The anti-reflective portion 211 is configured with a concave-convex structure, wherein the concave and convex are repeatedly arranged at predetermined intervals on the second surface SA of the semiconductor substrate 21. The depressions that form the tiny trenches of the anti-reflective portion 211 are filled by a fixed charge film 23 formed on the second surface SA of the semiconductor substrate 21. The protrusions of the concave-convex structure include a P-type semiconductor region 41 for the upper part of the photodiode PD, and a P-type semiconductor region 47 for the straight portion of the inter-pixel isolation portion 43. The spacing between the concave and convex is formed at a spacing equal to or less than the wavelength of light transmitted through the fixed charge film 23. The shapes of the protrusions and depressions of the concave-convex structure can be prism-shaped or cylindrical, or they can be pyramid-shaped (pyramidal shape), etc.

[0119] According to the pixel 2 configured as described above in the first modified example, the reflection of incident light can be further suppressed by further providing an anti-reflection portion 211. The anti-reflection portion 211 is also formed on the P-type semiconductor region 47 formed in the straight portion of the inter-pixel isolation portion 43, and since the area of ​​the P-type semiconductor region 47, which is part of the semiconductor substrate 21, is reduced, the electrical isolation characteristics between pixels are improved. It should be noted that the anti-reflection portion 211 may be formed at least on the light-incident surface of the photodiode PD, and may not be formed at the intersections and straight portions of the inter-pixel isolation portion 43.

[0120] (Second variation)

[0121] Figure 15 This is a cross-sectional view showing a second deformed example of pixel 2. When viewed in a plan view, along... Figure 15 The positions of the cross-sectional view taken along line X-X' and the cross-sectional view taken along line Y-Y' correspond to the positions of... Figure 4 The intersection and straight portion of the pixel isolation portion 43 corresponding to lines X-X' and Y-Y' in the graph.

[0122] exist Figure 15 In the second modified example shown, pixel 2 is replaced by transparent electrodes 221 and 222. Figure 3The insulating films 24 and 45 of the basic structure are shown. The inter-pixel insulating portion 43 includes a fixed charge film 44 formed on the side surface, a transparent electrode 222, and an air gap 46. Near the second surface SA of the intersection of the inter-pixel insulating portion 43, the transparent electrode 222 of the inter-pixel insulating portion 43 is connected to the transparent electrode 221 formed above the second surface SA. For example, a negative voltage (negative bias) is applied to the transparent electrode 221 in the peripheral portion of the pixel array portion 3. As materials for the transparent electrodes 221 and 222, transparent conductive materials such as indium tin oxide (ITO), zinc oxide, or indium zinc oxide are used, for example.

[0123] According to the second modified example of the pixel 2 configured as described above, by providing transparent electrodes 221 and 222 with applied negative bias to contact the fixed charge film 23 on the second surface SA of the semiconductor substrate 21 and the fixed charge film 44 of the inter-pixel insulating portion 43, the dark current suppression effect can be enhanced.

[0124] (Third variation)

[0125] Figure 16 This is a planar view showing a third variant of pixel 2. Figure 16 For example, the illustration is simplified by omitting the diagram of the fixed charge film 44 to make the accompanying drawings easier to view.

[0126] When a unit for arranging an on-chip lens 27 is defined as a pixel, Figure 3 The basic structure shown has the following characteristics: Figure 16 The configuration shown in Figure A is such that each pixel forms a photodiode PD and the signal charge generated in the photodiode PD is transmitted through a transmission transistor TG. The intersection 43A of the inter-pixel isolation portion 43 is formed in the plan view at the position corresponding to the corner of the generally rectangular pixel area and the corner of the photodiode PD.

[0127] On the other hand, such as Figure 16As shown in Figure B, there exists a pixel structure in which the photoelectric conversion region is divided into two halves to accommodate two photodiodes (PDs) for each pixel, and two transmission transistors (TGs) are arranged within a pixel, allowing the signal charge of the two photodiodes (PDs) to be read out individually. An overflow path can be provided in the P-type semiconductor region 41 between the two photodiodes (PDs). With the overflow path provided, the signal charge accumulates in each photodiode (PD) up to the height of the overflow path barrier, and when the barrier height is exceeded, the signal charge flows from one of the two photodiodes (PDs) to the other via the overflow path. When the signal charge of the two photodiodes (PDs) within a pixel is read out individually, a phase difference can be detected. When the signal charges of the two photodiodes (PDs) within a pixel are read out together, a similar... Figure 16 The signal of a photodiode PD for each pixel in A.

[0128] Figure 16 B is a third variation of pixel 2, showing a plan view of pixel 2 in which the inter-pixel isolation part 43 is applied to each pixel and each pixel is provided with two photodiodes PD and two transmission transistors TG.

[0129] When two photodiodes (PDs) are provided in each pixel, in the plan view, the intersection 43A of the inter-pixel isolation portion 43 is formed at a position corresponding to the corner of the rectangular pixel area and the corner of the photodiode PD. A P-type semiconductor region 41 is formed at the center of the pixel. This P-type semiconductor region 41 also serves as a position for forming an overflow path between the two photodiodes PD, and the inter-pixel isolation portion 43 is not formed at this position.

[0130] According to the pixel 2 of the third variant configured as described above, even in a pixel structure in which each pixel is provided with two photodiodes PD and two transmission transistors TG, cracking can be minimized by providing the inter-pixel isolation portion 43.

[0131] Note that for pixel 2, two or more arbitrary combinations of the structures of the first to third modifications described above can be appropriately adopted. For example, the first and second modifications can be combined to provide a structure with an anti-reflective portion 211 and transparent electrodes 221 and 222 having an uneven structure.

[0132] <6. Operational Effects of the Inter-pixel Isolation Section of this Disclosure>

[0133] refer to Figure 17 The advantages of the inter-pixel isolation portion 43 of pixel 2 compared with other inter-pixel isolation structures will be described.

[0134] Figure 17A to C are isolation structures that allow at least a portion of the intersection 43A or straight portion 43B of the inter-pixel isolation portion 43 to penetrate, and are used to compare the effect of minimizing breakage according to the position of the penetration portion. Figure 17 In diagrams A to C, the shaded areas represent the locations of the portions that penetrate the semiconductor substrate 21. The structure of the inter-pixel isolation portion 43 of pixel 2 is... Figure 17 The structure shown in B is such that only the intersection 43A is penetrated.

[0135] Figure 17 Figure A illustrates an inter-pixel isolation structure, wherein the straight portion 43B of the inter-pixel isolation portion 43 is formed to penetrate the semiconductor substrate 21. With this inter-pixel isolation structure, the number of penetrating portions is large and the mechanical strength is low. Furthermore, although it is believed that cracks easily propagate along the planar direction of the silicon substrate, when… Figure 17 When a crack occurs in the inter-pixel isolation section 43 of the inter-pixel isolation structure of A, it is considered that the crack is unlikely to propagate.

[0136] Figure 17 Figure B illustrates an inter-pixel isolation structure in which the intersection 43A of the inter-pixel isolation portion 43 is formed to penetrate the semiconductor substrate 21. With this inter-pixel isolation structure, the number of penetrated portions is small and the mechanical strength is high. Furthermore, when a breakage occurs in the inter-pixel isolation portion 43, the breakage is considered unlikely to... Figure 17 It propagates in the pixel-isolated structure of B.

[0137] Figure 17 Figure C illustrates an inter-pixel isolation structure in which a portion of the straight portion 43B forming the inter-pixel isolation section 43 penetrates the semiconductor substrate 21. With this inter-pixel isolation structure, the number of penetrated portions is small, and the mechanical strength is high. Furthermore, when a breakage occurs in the inter-pixel isolation section 43, the breakage is considered unlikely to... Figure 17 It propagates in the pixel-isolated structure of C.

[0138] Based on the above, it is believed that Figure 17 The inter-pixel isolation structure from A to C has a structure in which a break is unlikely to propagate. Then, from the point of view of mechanical strength, Figure 17 The pixel isolation structure between B and C is more than Figure 17 The pixel isolation structure of A is preferred. Furthermore, in Figure 17 In the pixel-to-pixel isolation structure of B and C, in the event of a breakage, Figure 17 The inter-pixel isolation structure of C has the potential to affect four pixels, while Figure 17 The pixel isolation structure of B is limited to affecting two pixels.

[0139] As described above, the inter-pixel insulation portion 43 of pixel 2 has a structure with high mechanical strength that minimizes breakage, and in which breakage is unlikely to propagate.

[0140] <7. Example of a second configuration for pixels>

[0141] Next, see Figure 18 and Figure 19 This section describes a second configuration example of pixel 2 in the light detection device 1.

[0142] Figure 18 This is a cross-sectional view of pixel 2 showing a second configuration example of the light detection device 1. Figure 19 This is a planar view representing pixel 2 of the second configuration example. Figure 18 It shows along Figure 19 A cross-sectional view taken from the Y-Y' line, and Figure 19 It shows along Figure 18 A cross-sectional view taken from the Z-Z' line.

[0143] exist Figure 18 and Figure 19 In this document, the parts corresponding to those in the first configuration example above are indicated by the same reference numerals, and repeated descriptions are omitted as appropriate.

[0144] In the first configuration example described above, pixel 2 has a structure in which the on-chip lens 27 is arranged in units of pixels. Conversely, in the second configuration example, in pixel 2, one on-chip lens 27 is arranged for every four pixels arranged in a 2×2 configuration. The color filter 25 has the same color arranged in units of four pixels sharing the on-chip lens 27. Hereinafter, the 2×2 arrangement of four pixels sharing the on-chip lens 27 and having the same color set therein in the color filter 25 is also referred to as a shared unit. In the color filter 25, for example, red (R), green (G), and blue (B) are arranged in a Bayer pattern in units of shared units. Figure 18 A cross-sectional view centered on two adjacent pixels is shown, in which an on-chip lens 27 and a color filter 25 of the same color (G) are arranged.

[0145] In pixel 2 of the second configuration example, the configuration of the inter-pixel isolation portion 43 differs further from that of the first configuration example described above. The inter-pixel isolation portion 43 of the first configuration example has a structure including a fixed charge film 44 formed on a side surface, an insulating film 45, and an air gap 46 formed in the center portion inside the insulating film 45. Conversely, in the second configuration example, the inter-pixel isolation portion 43, which serves as the boundary of a shared unit (hereinafter referred to as the shared unit boundary), includes, as... Figure 18 and 19As shown, a fixed charge film 44, a high refractive index film 401, an insulating film 45 are formed on the side surface, etc., and an air gap 46 is formed in the center of the inner side of the insulating film 45. Compared with the inter-pixel isolation portion 43 of the first configuration example, a high refractive index film 401 is newly added between the fixed charge film 44 and the insulating film 45 in the inter-pixel isolation portion 43 at the boundary of the shared unit. On the other hand, the inter-pixel isolation portion 43 inside the shared unit (hereinafter referred to as the shared unit interior) has only the fixed charge film 44 and the high refractive index film 401 on its inner side.

[0146] Although the word "and" was omitted Figure 3 The diagram corresponds to the X-X' cross-sectional view. However, in the second configuration example, the inter-pixel isolation portion 43 also has a structure in which the semiconductor substrate 21 is completely isolated at the intersection 43A corresponding to the corner of the pixel region, and on the second surface SA side, the insulating film 45 of the inter-pixel isolation portion 43 is connected to the insulating film 24 formed on the second surface SA. Furthermore, the fixed charge film 44 formed on the side surface of the inter-pixel isolation portion 43 and the fixed charge film 23 formed on the second surface SA are also connected.

[0147] The inter-pixel isolation section 43 at the boundary of the shared unit has color filters 25 of different colors on both sides of the inter-pixel isolation section 43 for pixels 2 on either side, and can also be referred to as an inter-pixel isolation section 43 between color filters of different colors. On the other hand, in the inter-pixel isolation section 43 inside the shared unit, for pixels 2 on both sides, there are color filters 25 of the same color on both sides of the inter-pixel isolation section 43, and can also be referred to as an inter-pixel isolation section 43 between color filters of the same color.

[0148] As from Figure 18As can be seen from the cross-sectional view, the pixel isolation portion 43 inside the shared unit and the pixel isolation portion 43 at the boundary of the shared unit share the common feature that they do not penetrate the semiconductor substrate 21, and a portion of the semiconductor substrate 21 on the second surface SA side is retained, in which a P-type semiconductor region 47 is formed. On the other hand, the pixel isolation portion 43 inside the shared unit and the pixel isolation portion 43 at the boundary of the shared unit differ in the width and depth of the trench. Specifically, in the pixel isolation portion 43 inside the shared unit, the depth of the trench from the first surface FA side of the semiconductor substrate 21 is shorter than that in the pixel isolation portion 43 at the boundary of the shared unit, and the width of the trench in the pixel isolation portion 43 inside the shared unit is also narrower than that in the pixel isolation portion 43 at the boundary of the shared unit. In other words, by making the width of the trench of the inter-pixel isolation portion 43 inside the shared unit narrower than the width of the trench of the inter-pixel isolation portion 43 at the boundary of the shared unit during the trenching process of the inter-pixel isolation portion 43, the depth of the trench of the inter-pixel isolation portion 43 inside the shared unit is formed to be shallower than the depth of the inter-pixel isolation portion 43 at the boundary of the shared unit. Furthermore, during the process of embedding the high-refractive-index film 401 into the trench, since the trench width is narrow, no gap remains, and there is no space to form an insulating film 45 or an air gap 46 in the inter-pixel insulation portion 43 inside the shared unit. On the other hand, in the inter-pixel isolation portion 43 at the boundary of the shared unit where the trench is wider, gaps remain even after the high-refractive-index film 401 is embedded, and thus an insulating film 45 and an air gap 46 are formed on the inner side of the high-refractive-index film 401. Therefore, the configuration of the material embedded in the inter-pixel isolation portion 43 differs between the inter-pixel isolation portion 43 at the boundary of the shared unit and the inter-pixel isolation portion 43 inside the shared unit.

[0149] The high-refractive-index film 401 is a film made of a material whose refractive index is lower than that of silicon (Si), the material used as the semiconductor substrate 21, but higher than that of the inner insulating film 45 or the air gap 46. The refractive index of silicon is approximately 3.8, for example, the refractive index of SiO2, the material used as the insulating film 45, is approximately 1.4, and the refractive index of the air gap 46 is approximately 1.0. Therefore, materials with refractive indices of, for example, 1.5 to 3.0 can be used as the material for the high-refractive-index film 401, as well as insulating materials such as titanium oxide (TiO2), zirconium oxide (ZrO2), and tantalum oxide (Ta2O5). Alternatively, silicon nitride can also be used. For example, the refractive index of titanium oxide (TiO2) is approximately 2.35. The refractive index of zirconium oxide (ZrO2) is approximately 2.05, the refractive index of tantalum oxide (Ta2O5) is approximately 2.1, and the refractive index of silicon nitride is approximately 2.0.

[0150] In pixel 2 of the second configuration example described above, similar to the first configuration example, the inter-pixel isolation portion 43 has a structure in which the semiconductor substrate 21 is completely isolated at the intersection 43A corresponding to the corner of the pixel region, and has a structure in which a portion of the semiconductor substrate 21 is held connected by a P-type semiconductor region 47 near the second surface SA at the straight portion 43B. Therefore, compared to the inter-pixel isolation portion structure in which all pixel boundaries are completely isolated, cracking can be minimized.

[0151] Furthermore, the second configuration example of pixel 2 has a shared structure, wherein the on-chip lens 27 is shared among multiple pixels, and the inter-pixel isolation portion 43 at the boundary of the shared unit includes a fixed charge film 44; a high refractive index film 401 (first insulating material) and an insulating film 45 (second insulating material) with different refractive indices, and an air gap 46. The inter-pixel isolation portion 43 within the shared unit includes only the high refractive index film 401 (with a higher refractive index) and the insulating film 45 (with a lower refractive index), and does not include the insulating film 45 (with a lower refractive index) or the air gap 46. Therefore, the inter-pixel isolation portion 43 within the shared unit suppresses the scattering of light incident on the pixel, and the inter-pixel isolation portion 43 at the boundary of the shared unit performs total internal reflection of light incident on the pixel, effectively confining the incident light within the photodiode PD.

[0152] <8. Example of a third configuration for pixels>

[0153] Figure 20 This is a cross-sectional view showing a third configuration example of pixel 2 of light detection device 1. Figure 20 It shows the corresponding Figure 4 The X-X' line cross-section and the corresponding Y-Y' line cross-section are shown. The X-X' line is the line that passes through the corner of pixel 2, which has a rectangular pixel area, and the Y-Y' line is the line that intersects the center of the pixel area in the horizontal or vertical direction.

[0154] It should be noted that, also in Figure 20 In this document, the parts corresponding to those in the first configuration example above are indicated by the same reference numerals, and repeated descriptions are omitted as appropriate.

[0155] In the third configuration example, in the straight portion 43B of the inter-pixel isolation portion 43 shown in the Y-Y' cross-sectional view, there is a first trench structure 421 recessed from the first surface FA side of the semiconductor substrate 21 and a second trench structure 422 recessed from the second surface SA side, and a portion of the semiconductor substrate 21 remains between the first trench structure 421 and the second trench structure 422, having an unisolated region (non-isolated region). The trench structures of the first trench structure 421 and the second trench structure 422 are trench structures recessed from the interface of the semiconductor substrate 21 to a predetermined depth. The first trench structure 421 extends from the first surface FA to the predetermined depth, and the second trench structure 422 extends from the second surface SA to the predetermined depth. The non-isolated region of the semiconductor substrate 21 includes a P-type semiconductor region 47. Similar to the first configuration example, the first trench structure 421 has a fixed charge film 44, an insulating film 45, an air gap 46, and an STI 48 embedded therein. The second trench structure 422 has a fixed charge film 44, an insulating film 45, and an air gap 46 embedded therein. The insulating film 45 in the second trench structure 422 is connected to the insulating film 24 formed on the second surface SA. In addition, the fixed charge film 44 formed on the side surface of the second trench structure 422 is connected to the fixed charge film 23 formed on the second surface SA.

[0156] Since the structure of the intersection 43A of the inter-pixel isolation portion 43 shown in the X-X' cross-sectional view is similar to the structure of the first configuration example described above, its description is omitted.

[0157] In the third configuration example with the above structure, the pixel array portion 3 of the light detection device 1 has an inter-pixel isolation portion 43 at the boundary of each pixel 2. The inter-pixel isolation portion 43 has a first trench structure 421 recessed from the first surface FA side of the semiconductor substrate 21 and a second trench structure 422 recessed from the second surface SA side at the vertical portion 43B, and has a configuration in which a fixed charge film 44, an insulating film 45, and an air gap 46 are embedded therein. By adding a structure in which the second trench structure 422 is formed from the second surface SA side and the fixed charge film 44, the insulating film 45, and the air gap 46 are embedded, in addition to the first trench structure 421 similar to that in the first configuration example, the non-isolated area of ​​the semiconductor substrate 21 at the vertical portion 43B can be made smaller than the non-isolated area in the first configuration example. Therefore, the amount of light incident from adjacent pixels through the non-isolated area of ​​the semiconductor substrate 21 can be reduced, and thus the color mixing suppression can be enhanced beyond that of the first configuration example. Therefore, according to the third configuration example, the breakage can be minimized in a similar manner to the first configuration example, and color mixing can be suppressed to a greater extent than in the first configuration example.

[0158] <9. Variations of the Third Configuration Example>

[0159] A variation of pixel 2 based on the third configuration example described above will be described. (Refer to the reference...) Figure 20 The corresponding parts of the basic structure of the third configuration example described are indicated by the same reference numerals, and repeated descriptions are omitted appropriately.

[0160] (First variation)

[0161] Figure 21 This is a cross-sectional view showing a first variant of pixel 2 in a third configuration example. Figure 21 In the diagram, the X-X' section view corresponds to... Figure 4 A cross-sectional view of the intersection 43A of the pixel-inter-pixel isolation portion 43 of the X-X' line, and a cross-sectional view of the Y-Y' line corresponding to... Figure 4 A cross-sectional view of the straight portion 43B of the pixel-inter-pixel isolation portion 43 of the Y-Y' line. The X-X' cross-sectional view is similar. Figure 20 The third configuration example shown in the figure and Figure 3 The basic structure of the first configuration example shown in the figure.

[0162] exist Figure 21 In the first variation, the arrangement within the second groove structure 422 recessed from the second surface SA side in the Y-Y' cross-sectional view is similar to... Figure 20 The basic structure of the third configuration example shown is different. Specifically, Figure 20 The basic structure of the third configuration example shown has a configuration in which the fixed charge film 44, the insulating film 45, and the air gap 46 are embedded within the second trench structure 422. In contrast, Figure 21 The first modification has a configuration in which the fixed charge film 44 and the air gap 46 are embedded within the second trench structure 422. That is, in Figure 21 In the first variation, the embedding of the insulating film 45 into the second trench structure 422 is omitted. Thus, the embedding of the insulating film 45 into the second trench structure 422 can be omitted. Conversely, the embedding of the air gap 46 can be omitted, and a configuration in which the fixed charge film 44 and the insulating film 45 are embedded inside the second trench structure 422 can be adopted.

[0163] (Second variation)

[0164] Figure 22 This is a cross-sectional view of a second variant of pixel 2, illustrating a third configuration example. Figure 22 In the diagram, the X-X' section view corresponds to... Figure 4 A cross-sectional view of the intersection 43A of the pixel-inter-pixel isolation portion 43 of the X-X' line, and a cross-sectional view of the Y-Y' line corresponding to... Figure 4 A cross-sectional view of the straight portion 43B of the pixel-inter-pixel isolation portion 43 of the Y-Y' line. The X-X' cross-sectional view is similar. Figure 20 The third configuration example shown in the figure and Figure 3 The basic structure of the first configuration example shown in the figure.

[0165] Also in Figure 22 In the second variation, the arrangement within the second groove structure 422 recessed from the second surface SA side in the Y-Y' cross-sectional view is similar to... Figure 20 The basic structure differs from the third configuration example shown. Specifically, in the second variation, an embedding material 431, which is different from the material embedded in the first trench structure 421, is embedded inside the second trench structure 422. As the filling material 431, for example, the material of the high refractive index film 401 in the second configuration example described above can be used. For example, the embedding material 431 can be an insulating material such as titanium dioxide (TiO2), zirconium oxide (ZrO2), or tantalum oxide (Ta2O5), or alternatively, silicon nitride. Additionally, as... Figure 21 As shown in the first modified example, a fixed charge film 44 can also be formed on the bottom and side surfaces of the second trench structure 422, and a filling material 431 can be disposed on the inner side of the fixed charge film 44.

[0166] (Third variation)

[0167] Figure 23 This is a cross-sectional view showing a third variation of pixel 2 in a third configuration example. Figure 23 In the diagram, the X-X' section view corresponds to... Figure 4 A cross-sectional view of the intersection 43A of the pixel-inter-pixel isolation portion 43 of the X-X' line, and a cross-sectional view of the Y-Y' line corresponding to... Figure 4 A cross-sectional view of the straight portion 43B of the pixel-inter-pixel isolation portion 43 of the Y-Y' line. The X-X' cross-sectional view is similar. Figure 20 The third configuration example shown in the figure and Figure 3 The basic structure of the first configuration example shown in the figure.

[0168] exist Figure 23In a third variation, in the Y-Y' cross-sectional view, the second trench structure 422 recessed from the second surface SA side becomes a second trench structure 422A. The width of the second trench structure 422A in the planar direction is wider than the width of the first trench structure 421. The second trench structure 422A includes micro-trenches 422B, which are tiny trench structures formed near the trench sidewalls. Due to the micro-trenches 422B, the depth near the trench sidewalls of the second trench structure 422A is deeper than the height of the upper surface of the first trench structure 421. Therefore, the non-isolated area of ​​the semiconductor substrate 21 can be further reduced. By providing the overlapping area of ​​the first trench structure 421 and the second trench structure 422A in the depth direction (i.e., the direction perpendicular to the second surface SA of the semiconductor substrate 21) via micro-blades 422B, the amount of light incident from adjacent pixels through the non-isolated area of ​​the semiconductor substrate 21 can be reduced. Figure 23 In the example, the materials embedded inside the second trench structure 422A are a fixed charge film 44, an insulating film 45, and an air gap 46, which have the same configuration as the materials embedded in the first trench structure 421; however, as in Figure 22 In the second configuration example shown, the material embedded inside the second trench structure 422A may be different from the material embedded in the first trench structure 421.

[0169] (Fourth variation)

[0170] Figure 24 This is a cross-sectional view showing a fourth variation of pixel 2 in the third configuration example. Figure 24 In the diagram, the X-X' section view corresponds to... Figure 4 A cross-sectional view of the intersection 43A of the pixel-inter-pixel isolation portion 43 of the X-X' line, and a cross-sectional view of the Y-Y' line corresponding to... Figure 4 A cross-sectional view of the straight portion 43B of the pixel-inter-pixel isolation portion 43 of the Y-Y' line. The X-X' cross-sectional view is similar. Figure 20 The third configuration example shown in the figure and Figure 3 The basic structure of the first configuration example shown in the figure.

[0171] exist Figure 24In the fourth variation, in the Y-Y' cross-sectional view, the second trench structure 422 recessed from the second surface SA side becomes two second trench structures 422C. In the cross-sectional view, the first trench structure 421 is disposed between the two second trench structures 422C, and the two second trench structures 422C are disposed outside the first trench structure 421. The planar width of the two second trench structures 422C is narrower than the planar width of the first trench structure 421, and the depth of the recess from the second surface SA side is deeper than the height of the upper surface of the first trench structure 421. By providing an overlapping area of ​​the first trench structure 421 and the second trench structure 422C in the depth direction (i.e., the direction perpendicular to the second surface SA of the semiconductor substrate 21), the amount of light incident from adjacent pixels through the non-isolated area of ​​the semiconductor substrate 21 can be reduced. Figure 24 In the example, the insulating film 45 is embedded inside the two second trench structures 422C; however, as in Figure 22 In the second configuration example shown, a material different from the material embedded in the first trench structure 421 can be embedded.

[0172] Similarly, in the first to fourth variations of the third configuration example described above, cracking can be minimized in a manner similar to the first configuration example, and color mixing suppression can be enhanced beyond that of the first configuration example.

[0173] <10. Method for manufacturing pixels according to the third configuration example>

[0174] Next, we will refer to Figures 25 to 27 Description for manufacturing reference Figure 20 The method for pixel 2 in the third configuration example described. Figures 25 to 27 In the middle, there will be descriptions and references Figures 5 to 13 The first configuration example described differs from the method used to manufacture pixel 2.

[0175] refer to Figures 5 to 9 The steps for pixel 2 in the first configuration example described are similar in the third configuration example. (See reference...) Figures 5 to 9 In the described steps, the trench 101 formed by dry etching the semiconductor substrate 21 from the first surface FA side to a predetermined depth corresponds to the first trench structure 421 in the third configuration example.

[0176] Reference Figure 9 In the described steps, the entire semiconductor substrate 21 on which the wiring layer 22 is formed is inverted, bonded to a logic substrate manufactured in a separate process, and the semiconductor substrate 21 is thinned to the desired thickness.

[0177] Reference Figure 9 Following the described steps, such as Figure 25As shown in the Y-Y' cross-sectional view, in the region of the straight portion 43B that serves as the inter-pixel isolation portion 43, the semiconductor substrate 21 is recessed from the second surface SA side by dry etching to form a second trench structure 422, and an embedding material 441 is embedded inside the second trench structure 422. The embedding material 441 is the same material as the embedding material 111 embedded inside the trench 101 (first trench structure 421).

[0178] Next, as Figure 26 As shown, the second surface SA side of the semiconductor substrate 21 is further removed using methods such as wet etching, dry etching, and CMP. Therefore, the thickness of the semiconductor substrate 21 is reduced, causing the embedded material 111 to protrude at the intersection 43A in the X-X' cross-sectional view, and the embedded material 441 to protrude at the straight portion 43B in the Y-Y' cross-sectional view.

[0179] Next, as Figure 27 As shown in the X-X' cross-sectional view, the embedded material 111 in the trench 101 of the inter-pixel isolation portion 43 is removed, and a cavity 121 is formed. This cavity 121 corresponds to the first trench structure 421 in the third configuration example. Furthermore, as... Figure 27 As shown in the Y-Y' cross-sectional view, the embedded material 441 in the second trench structure 422 of the embedded inter-pixel isolation portion 43 is also removed along with the embedded material 111. The embedded materials 111 and 442 can be removed by, for example, wet etching or isotropic dry etching.

[0180] Figure 27 The subsequent steps are similar to those in the reference. Figure 12 The steps in the manufacturing method of pixel 2 in the first configuration example described are as follows. Specifically, a fixed charge film 44, an insulating film 45, and an air gap 46 are formed in the first trench structure 421 (cavity 121) and the second trench structure 422, and a fixed charge film 23 and an insulating film 24 are also formed on the second surface SA of the semiconductor substrate 21. Subsequently, as referenced... Figure 13 As described, the inter-pixel light-shielding film 26, the color filter 25, and the on-chip lens 27 are formed on the upper surface of the insulating film 24 above the second surface SA of the semiconductor substrate 21, and are completed. Figure 20 Pixel 2 in the third configuration example shown.

[0181] Figure 20 Pixel 2 in the third configuration example shown can be manufactured using the method described above.

[0182] <11. Configuration Examples of Electronic Devices>

[0183] The aforementioned light detection device 1 can be applied to various electronic devices, such as imaging systems (such as digital still cameras or digital video cameras), mobile phones with imaging capabilities, or other devices with imaging capabilities.

[0184] Figure 28 This is a block diagram illustrating an example configuration of an electronic device.

[0185] like Figure 28 As shown, electronic device 301 includes an optical system 302, a light detection device 303, a digital signal processor (DSP) 304, a display device 305, an operating system 306, a memory 307, a recording device 308, and a power supply system 309. The DSP 304, display device 305, operating system 306, memory 307, recording device 308, and power supply system 309 are interconnected via a bus 310. For example, electronic device 301 is an imaging device capable of imaging still images and moving images.

[0186] The optical system 302 includes one or more lenses that guide image light (incident light) from the object to the light detection device 303 and form an image on the light receiving surface (sensor section) of the light detection device 303.

[0187] The light detection device 303 described above uses the same configuration as the light detection device 1. In the light detection device 303, electrons, which serve as signal charges, are accumulated over a certain period based on the image formed on the light-receiving surface via the optical system 302. Then, a signal corresponding to the electrons accumulated in the light detection device 303 is provided to the DSP 304.

[0188] The DSP 304 performs various types of signal processing on the signal from the photodetector 303 to generate an image, and temporarily stores the image data in the memory 307. The image data stored in the memory 307 is either recorded in the recording device 308 or provided to the display device 305 for display. In addition, the operating system 306 receives various user operations and supplies operation signals to the various blocks of the electronic device 301, and the power supply system 309 supplies the power required to drive the various blocks of the electronic device 301.

[0189] In the electronic device 301 configured in this way, by applying the aforementioned light detection device 1 to the light detection device 303, a pixel structure with minimal breakage suppression can be achieved. Therefore, excellent durability and high-quality captured images can be generated.

[0190] <12. Examples of Image Sensor Applications>

[0191] Figure 29 This is a diagram illustrating an example of the use of the aforementioned light detection device 1 as an image sensor.

[0192] For example, when the light detection device 1 described above is an image sensor, the light detection device 1 can be used to sense various types of light, such as visible light, infrared light, ultraviolet light, or X-rays.

[0193] Devices that image images provided for viewing purposes, such as digital cameras and mobile devices with camera functions. Devices provided for traffic purposes, such as onboard sensors that image the front, rear, surrounding environment, and interior of a vehicle; surveillance cameras used to monitor moving vehicles and roads; and distance measuring sensors that measure distances between vehicles, are used for safe driving, such as automatic stopping and driver status recognition. A device for capturing user gestures and performing device operations based on those gestures for household appliances such as televisions, refrigerators, and air conditioners. Devices for medical and healthcare purposes (such as endoscopes) and devices that perform angiography by receiving infrared light. Devices provided for security, such as security surveillance cameras and separate authentication cameras. Devices for cosmetic purposes, such as skin measurement instruments for imaging the skin and microscopes for imaging the scalp. Devices designed for sports, such as action cameras or wearable cameras for sports applications, etc. Devices provided for agriculture, such as cameras used to monitor the conditions of fields and crops. <13. Examples of the Application of Endoscopic Surgical Systems> The technology disclosed herein (the Technology) can be applied to a variety of products. For example, the Technology disclosed herein can be applied to endoscopic surgical systems.

[0194] Figure 30 This is a diagram illustrating an example of a schematic configuration of an endoscopic surgical system to which the technology (the present technology) according to this disclosure can be applied.

[0195] Figure 30 The illustration depicts an operator (physician) 11131 performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgical system 11000. As shown, the endoscopic surgical system 11000 includes an endoscope 11100, other surgical instruments 11110 such as a pneumoperitoneum tube 11111 and an energy device 11112, a support arm device 11120 supporting the endoscope 11100, and a trolley 11200 equipped with various endoscopic surgical devices.

[0196] Endoscope 11100 includes a lens barrel 11101 and a camera 11102 connected to the proximal end of the lens barrel 11101. The lens barrel 11101 has a region of a predetermined length starting from its distal end for insertion into the body cavity of a patient 11132. In the illustrated example, endoscope 11100 is shown with a rigid lens barrel 11101 as a rigid endoscope. However, endoscope 11100 may additionally include a flexible endoscope having a flexible lens barrel 11101.

[0197] The lens barrel 11101 has an opening at its distal end, in which the objective lens is mounted. A light source device 11203 is connected to the endoscope 11100, such that light generated by the light source device 11203 is introduced into the front end of the lens barrel 11101 by a light guide extending inside the lens barrel 11101, and then illuminates the object of observation within the body cavity of the patient 11132 via the objective lens. Furthermore, the endoscope 11100 can be a direct-viewing endoscope, an oblique-viewing endoscope, or a lateral-viewing endoscope.

[0198] An optical system and an image pickup element are housed inside the camera 11102, allowing reflected light (observation light) from the observed target to be converged onto the image pickup element via the optical system. The image pickup element performs photoelectric conversion on the observation light, generating an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. The image signal is transmitted to the CCU11201 as RAW data.

[0199] The CCU 11201 includes a central processing unit (CPU), a graphics processing unit (GPU), etc., and controls the operation of the endoscope 11100 and the display device 11202 as a whole. In addition, the CCU 11201 receives image signals from the camera 11102 and performs various image processing on the image signals for displaying images based on the image signals, such as, for example, development processing (de-mosaic processing).

[0200] The display device 11202 displays an image on itself based on an image signal under the control of the CCU 11201, wherein the CCU 11201 performs image processing on the image signal.

[0201] The light source device 11203 has a light source such as a light-emitting diode (LED) to supply illumination light to the endoscope 11100 for imaging the surgical area, etc.

[0202] Input device 11204 is the input interface of endoscopic surgery system 11000. Users can input various information or instructions into endoscopic surgery system 11000 through input device 11204. For example, users can input instructions to change the imaging conditions of endoscope 11100 (type of illumination light, magnification, focal length, etc.).

[0203] The treatment tool control device 11205 controls the drive of the energy device 11112 for burning or cutting tissue, sealing blood vessels, etc. To ensure the field of vision of the endoscope 11100 and to ensure the surgeon's working space, the pneumoperitoneum device 11206 supplies gas into the patient's body cavity 11132 through the pneumoperitoneum tube 11111, causing the cavity to expand. The recorder 11207 is a device capable of recording various information related to the surgery. The printer 11208 is a device capable of printing various information related to the surgery in various forms (such as text, images, or graphics).

[0204] Additionally, the light source device 11203 supplying illumination light when the surgical area is imaged onto the endoscope 11100 may also include a white light source, such as an LED, a laser light source, or a combination thereof. When the white light source includes a combination of red, green, and blue (RGB) laser light sources, the white balance of the captured image can be adjusted by the light source device 11203 because the output intensity and timing can be controlled with high precision for each color (each wavelength). Furthermore, in this case, if the laser beams from each RGB laser light source are time-divisionally illuminating the target and the driving of the image acquisition element of the camera 11102 is controlled synchronously with the illumination timing, then images corresponding to the R, G, and B colors respectively can be captured time-divisionally. According to this method, color images can be obtained even without setting a color filter on the imaging element.

[0205] Furthermore, the light source device 11203 can be controlled to change the intensity of the light to be output at predetermined intervals. By controlling the driving of the image acquisition element of the camera 11102 in time-division multiplexing to acquire and synthesize images in sync with the timing of the light intensity changes, high dynamic range images without underexposure blocking shadows and overexposure highlights can be produced.

[0206] Furthermore, the light source device 11203 can be configured to provide light of a predetermined wavelength band for special light observation. In special light observation, narrow-band light observation (narrow-band light observation) is performed by irradiating a narrow-band light with high contrast onto specified tissues such as blood vessels in the superficial layer of the mucosa using light with a narrower frequency band than the illumination light used in normal observation (i.e., white light) by utilizing the wavelength dependence of light absorption by biological tissues. Alternatively, in special light observation, fluorescence observation can also be performed to obtain an image from fluorescence generated by irradiation with excitation light. In fluorescence observation, fluorescence from biological tissues can be observed by irradiating biological tissues with excitation light (autofluorescence observation), or a fluorescence image can be obtained by locally injecting a reagent such as indocyanine green (ICG) into biological tissues and irradiating the biological tissues with excitation light corresponding to the fluorescence wavelength of the reagent. The light source device 11203 can be configured to provide narrow-band light and / or excitation light suitable for special light observation as described above.

[0207] Figure 31 The diagram is in Figure 30 The diagram shows an example of the functional configuration of camera 11102 and CCU11201.

[0208] Camera 11102 includes a lens unit 11401, an image acquisition unit 11402, a driving unit 11403, a communication unit 11404, and a camera control unit 11405. CCU 11201 includes a communication unit 11411, an image processing unit 11412, and a control unit 11413. Camera 11102 and CCU 11201 are connected via a transmission cable 11400 for communication with each other.

[0209] Lens unit 11401 is an optical system disposed at the connection point with lens barrel 11101. Observation light acquired from the distal end of lens barrel 11101 is guided to camera 11102 and introduced into lens unit 11401. Lens unit 11401 includes a combination of multiple lenses, including zoom lenses and focusing lenses.

[0210] Image acquisition unit 11402 includes image acquisition elements. The number of image acquisition elements included in image acquisition unit 11402 can be one (single-plate type) or multiple (multi-plate type). When image acquisition unit 11402 is configured as a multi-plate type camera unit, for example, image signals corresponding to each R, G, and B are generated by the image acquisition elements, and the image signals can be synthesized to obtain a color image. Alternatively, image acquisition unit 11402 may include a pair of image acquisition elements for acquiring right-eye and left-eye image signals compatible with three-dimensional (3D) display. In the case of 3D display, the surgical operator 11131 can more accurately grasp the depth of biological tissue in the surgical area. It should be noted that when image acquisition unit 11402 is configured as a stereoscopic camera unit, multiple lens units 11401 of the system are provided corresponding to a single image acquisition element.

[0211] Furthermore, the image acquisition unit 11402 is not necessarily mounted on the camera 11102. For example, the image acquisition unit 11402 may be located inside the lens barrel 11101, immediately behind the objective lens.

[0212] The drive unit 11403 includes an actuator and, under the control of the camera control unit 11405, moves the zoom lens and focusing lens of the lens unit 11401 a predetermined distance along the optical axis. As a result, the magnification and focus of the image captured by the image acquisition unit 11402 can be appropriately adjusted.

[0213] Communication unit 11404 includes communication means for sending and receiving various information to and from CCU 11201. Communication unit 11404 transmits image signals acquired from image acquisition unit 11402 as RAW data to CCU 11201 via transmission cable 11400.

[0214] In addition, the communication unit 11404 receives control signals from the CCU 11201 for controlling the camera 11102 and supplies the control signals to the camera control unit 11405. The control signals include information related to image acquisition conditions, such as information specifying the frame rate of the acquired image, information specifying the exposure value when the image is acquired, and / or information specifying the magnification and focus of the acquired image.

[0215] It should be noted that image picking conditions such as frame rate, exposure value, magnification, or focus can be specified by the user or automatically set by the control unit 11413 of the CCU 11201 based on the acquired image signal. In the latter case, the automatic exposure (AE) function, automatic focus (AF) function, and automatic white balance (AWB) function are combined in the endoscope 11100.

[0216] The camera control unit 11405 controls the driving of the camera 11102 based on the control signals received from the CCU 111201 via the communication unit 11404.

[0217] The communication unit 11411 includes a communication device for sending and receiving various information to and from the camera 11102. The communication unit 11411 receives image signals transmitted from the camera 11102 via a transmission cable 11400.

[0218] In addition, the communication unit 11411 sends control signals to the camera 11102 to control the camera 11102. The image signals and control signals can be transmitted via electrical communication, optical communication, etc.

[0219] The image processing unit 11412 performs various image processing operations on the image signal in RAW data form sent to it from the camera 11102.

[0220] The control unit 11413 performs various controls related to capturing images of the surgical area of ​​the endoscope 11100 and displaying the images obtained by capturing images of the surgical area. For example, the control unit 11413 generates control signals for controlling the drive of the camera 11102.

[0221] Furthermore, the control unit 11413 controls the display device 11202 to display an image of the surgical area, etc., based on the image signal processed by the image processing unit 11412. Thus, the control unit 11413 can use various image recognition technologies to identify various objects in the acquired image. For example, the control unit 11413 can identify surgical tools such as tweezers, specific living areas, bleeding, and fogging when using the energy device 11112 by detecting the shape and color of the edges of objects included in the acquired image. When the control unit 11413 controls the display device 11202 to display the acquired image, the control unit 11413 can use the recognition results to display various surgical support information in a manner that overlaps with the image of the surgical area. By overlaying surgical support information and providing prompts to the surgeon 11131, the burden on the surgeon 11131 can be reduced, allowing the surgeon 11131 to perform surgery reliably.

[0222] The transmission cable 11400 connecting the camera 11102 and CCU11201 to each other is an electrical signal cable prepared for electrical signal communication, an optical fiber prepared for optical communication, or a composite cable prepared for both electrical and optical communication.

[0223] Here, although communication is performed via wired communication using transmission cable 11400 in the illustrated example, communication between camera 11102 and CCU 11201 can be performed wirelessly.

[0224] Examples of endoscopic surgical systems to which the technology according to this disclosure can be applied have been described above. The technology according to this disclosure can be applied to the image acquisition unit 11402 of the camera 11102 in the above configuration. Specifically, the light detection device 1 described above can be used as the image acquisition unit 11402. By applying the technology according to this disclosure to the image acquisition unit 11402, the size of the camera 11102 can be reduced, while achieving excellent durability and obtaining clearer images of the surgical site.

[0225] It should be noted that, in this document, the endoscopic surgical system has been described as an example, but the techniques according to this disclosure can be applied to, for example, microsurgical systems.

[0226] <14. Examples of Mobile Applications>

[0227] The technology disclosed herein (the Technology) can be applied to a variety of products. For example, the Technology disclosed herein can also be implemented as a device installed in any type of mobile object, such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, aircraft, drones, ships, and robots.

[0228] Figure 32 This is a block diagram illustrating a schematic configuration example of a vehicle control system, which is an example of a moving object control system to which the technology according to this disclosure can be applied.

[0229] The vehicle control system 12000 includes multiple electronic control units interconnected via a communication network 12001. Figure 32 In the example shown, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. Furthermore, as examples of the functional structure of the integrated control unit 12050, a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface (I / F) 12053 are shown.

[0230] The drive system control unit 12010 controls the operation of devices related to the vehicle's drive system according to various programs. For example, the drive system control unit 12010 is used as a control device for drive force generating devices (such as internal combustion engines, drive motors, etc.) that generate drive force for the vehicle, drive force transmission mechanisms that transmit drive force to the wheels, steering mechanisms that adjust the vehicle's steering angle, and braking devices that generate braking force for the vehicle.

[0231] The body system control unit 12020 controls the operation of various devices installed on the vehicle body according to various programs. For example, the body system control unit 12020 is used as a control device for keyless entry systems, smart key systems, power windows, or various lights such as headlights, taillights, brake lights, turn signals, fog lights, etc. In this case, radio waves or signals from various switches, which are used as a substitute for keys, can be input to the body system control unit 12020. The body system control unit 12020 receives these input radio waves or signals and controls the vehicle's door locks, power windows, lights, etc.

[0232] The external information detection unit 12030 detects external information, including information from outside the vehicle, which is part of the vehicle control system 12000. For example, an imaging unit 12031 is connected to the external information detection unit 12030. The external information detection unit 12030 causes the imaging unit 12031 to image an image of the external environment and receives the image. Furthermore, the external information detection unit 12030 can also perform processing based on the received image, such as detecting people, vehicles, obstacles, signs, text on the road surface, etc., or detecting their distance.

[0233] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output an electrical signal as an image, or it can output an electrical signal as information about the measured distance. Furthermore, the light received by the imaging unit 12031 can be visible light, or it can be invisible light such as infrared light.

[0234] The in-vehicle information detection unit 12040 detects information about the interior of the vehicle. The in-vehicle information detection unit 12040 is connected, for example, to a driver state detection unit 12041 that detects the driver's state. The driver state detection unit 12041 includes, for example, a camera that images the driver. Based on the detection information input from the driver state detection unit 12041, the in-vehicle information detection unit 12040 can calculate the driver's fatigue level or concentration level, or determine whether the driver is drowsy.

[0235] The microcomputer 12051 can calculate control target values ​​for the drive force generation device, steering mechanism, or braking device based on information about the vehicle's interior or exterior obtained by the external information detection unit 12030 or the internal information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control designed to implement functions of an advanced driver assistance system (ADAS), including collision avoidance or shock absorption for the vehicle, following driving based on following distance, maintaining vehicle speed, collision warning, lane departure warning, etc.

[0236] In addition, the microcomputer 12051 controls the drive force generating device, steering mechanism, braking device, etc., based on information about the outside or inside of the vehicle obtained by the external information detection unit 12030 or the internal information detection unit 12040, and can perform cooperative control for autonomous driving, which enables the vehicle to drive automatically without relying on the driver's operation.

[0237] Additionally, the microcomputer 12051 can output control commands to the body system control unit 12020 based on information about the outside of the vehicle obtained by the external information detection unit 12030. For example, the microcomputer 12051 can perform cooperative control aimed at preventing glare by controlling the headlights to switch from high beam to low beam based on the position of the vehicle in front or oncoming vehicle detected by the external information detection unit 12030.

[0238] The sound / image output unit 12052 sends an output signal of at least one of sound and image to an output device capable of visually or audibly notifying the vehicle occupants or the outside of the vehicle of information. Figure 32 In the example, audio speaker 12061, display unit 12062, and instrument panel 12063 are shown as output devices. For example, display unit 12062 may include at least one of an on-board display and a head-up display.

[0239] Figure 33 This is a diagram showing an example of the installation position of the imaging unit 12031.

[0240] exist Figure 33 The imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104 and 12105.

[0241] Imaging units 12101, 12102, 12103, 12104, and 12105 are installed, for example, on the front nose, side mirrors, rear bumper, and rear door of vehicle 12100, and on the upper part of the windshield inside the vehicle. Imaging unit 12101 on the front nose inside the vehicle and imaging unit 12105 on the upper part of the windshield primarily acquire images of the front of vehicle 12100. Imaging units 12102 and 12103 on the side mirrors primarily acquire images of the side surfaces of vehicle 12100. Imaging unit 12104 on the rear bumper or rear door primarily acquires images of the rear of vehicle 12100. Imaging unit 12105 on the upper part of the windshield inside the vehicle is mainly used to detect vehicles, pedestrians, obstacles, signals, traffic signs, lanes, etc., ahead.

[0242] It should be noted that Figure 33 Examples of the imaging ranges of imaging units 12101 to 12104 are shown. Imaging range 12111 represents the imaging range of imaging unit 12101 installed on the front nose. Imaging ranges 12112 and 12113 represent the imaging ranges of imaging units 12102 and 12103 installed on the side mirrors, respectively. Imaging range 12114 represents the imaging range of imaging unit 12104 installed on the rear bumper or rear door. For example, a planar image of the vehicle 12100 viewed from above can be obtained by overlaying the image data captured by imaging units 12101 to 12104.

[0243] At least one of the imaging units 12101 to 12104 may have the function of acquiring distance information. For example, at least one of the imaging 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.

[0244] For example, the microcomputer 12051 obtains the distance to each three-dimensional object within the imaging range 12111 to 12114 and the time change of that distance (relative speed relative to the vehicle 12100) based on distance information obtained from the imaging units 12101 to 12104. It then extracts the three-dimensional object (specifically, the closest three-dimensional object on the vehicle 12100's travel path) traveling in substantially the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or greater) as the vehicle ahead. Furthermore, the microcomputer 12051 can preset a following distance to stay ahead of the vehicle ahead and execute automatic braking control (including follow-stop control), automatic acceleration control (including follow-start control), etc. Thus, coordinated control for autonomous driving, enabling the vehicle to drive automatically without relying on driver operation, is possible.

[0245] For example, the microcomputer 12051 can classify three-dimensional object data related to three-dimensional objects into three-dimensional objects such as two-wheeled vehicles, ordinary vehicles, large vehicles, and pedestrians based on distance information obtained from imaging units 12101 to 12104, extract the three-dimensional object data, and use the three-dimensional object data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around vehicle 12100 as obstacles that the driver of vehicle 12100 can visually recognize and obstacles that the driver of vehicle 12100 cannot visually recognize. Then, the microcomputer 12051 determines a collision risk indicating the risk of collision with each obstacle. If the collision risk is equal to or higher than a set value and therefore there is a possibility of collision, the microcomputer 12051 outputs a warning to the driver via audio speaker 12061 or display unit 12062, and performs forced deceleration or evasive steering via drive system control unit 12010. The microcomputer 12051 can thereby assist driving to avoid collisions.

[0246] At least one of the imaging units 12101 to 12104 can be an infrared camera that detects infrared light. For example, the microcomputer 12051 can identify a pedestrian by determining whether a pedestrian exists in the image captured by the imaging units 12101 to 12104. This pedestrian identification is performed, for example, by extracting feature points from the image captured by the imaging units 12101 to 12104, which are infrared cameras, and by performing pattern matching processing on a series of feature points indicating the outline of an object to determine whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian exists in the image captured by the imaging units 12101 to 12104 and identifies the pedestrian, the sound / image output unit 12052 controls the display unit 12062 to overlay and display a square outline for emphasizing the identified pedestrian. The sound / image output unit 12052 can also control the display unit 12062 to display an icon or the like representing a pedestrian at a desired location.

[0247] Examples of vehicle control systems to which the technology according to this disclosure can be applied have been described above. The technology according to this disclosure can be applied to the imaging unit 12031 described above. Specifically, the light detection device 1 described above can be applied to the imaging unit 12031. By applying the technology according to this disclosure to the imaging unit 12031, the size can be reduced while achieving excellent durability, obtaining a clearer captured image, and acquiring distance information. Furthermore, by using the acquired imaging image and distance information, driver fatigue can be reduced and the safety of the driver and vehicle can be increased.

[0248] The above example illustrates a photodetector with a first conductivity type of P-type and a second conductivity type of N-type, using electrons as signal charges. However, this method can also be applied to a photodetector using holes as signal charges. That is, the first conductivity type can be N-type, the second conductivity type can be P-type, and the conductivity types of the various semiconductor regions can be reversed.

[0249] The technology disclosed herein is not limited to optical detection devices that detect the distribution of incident visible light and image that distribution as an image, but can be applied to all optical detection devices (physical quantity distribution detection devices), such as optical detection devices that image the distribution of incident infrared and X-rays, as well as particles in an image, and fingerprint detection sensors that detect the distribution of other physical quantities (such as pressure and capacitance) and image that distribution in a broad sense.

[0250] Here, a system means a group of multiple components (devices, modules (parts), etc.), and it is irrelevant whether all components are housed in the same housing. Therefore, multiple devices housed in separate housings and connected via a network, and a single device in which multiple modules are housed in a single housing, are both systems.

[0251] The implementation of the technology disclosed herein is not limited to the above-described implementation, and various modifications can be made without departing from the spirit of the technology disclosed herein.

[0252] The effects described in this manual are merely examples, and other effects besides those described in this manual can also be achieved.

[0253] It should be noted that the technology disclosed herein can be configured as follows. (1)

[0255] A light detection device, comprising: A pixel array unit, wherein multiple pixels are arranged on a semiconductor substrate along row and column directions, wherein Pixel array units have inter-pixel isolation portions between pixels. In the planar view, the inter-pixel isolation portion has a first intersection, a second intersection, and a straight portion located between the first intersection and the second intersection. In the cross-sectional view, both the first and second intersections have trench structures that isolate the semiconductor substrate from its first surface to its second surface, with the second surface disposed on the opposite side of the first surface. In the cross-sectional view, the vertical portion has a semiconductor region and a trench structure that are part of a semiconductor substrate. (2)

[0257] According to the optical detection device in (1), wherein, The second surface of the semiconductor substrate is a light-incident surface on which light is incident, and the second surface is disposed on the side opposite to the first surface forming the pixel transistor. The semiconductor region of the vertical portion is formed on the second surface side of the semiconductor substrate. (3)

[0259] According to the optical detection device of (1) or (2), wherein, The semiconductor region includes a second conductivity type semiconductor region, the conductivity type of which is opposite to that of the first conductivity type semiconductor region constituting the charge accumulation region of the photoelectric conversion section of each pixel. (4)

[0261] According to any one of (1) to (3) of the optical detection device, wherein, The semiconductor region is also formed between the inter-pixel isolation section and the photoelectric conversion section. (5)

[0263] According to any one of (1) to (4) of the optical detection device, wherein, The inter-pixel isolation portion has an STI in the region on the first surface side of the semiconductor substrate. (6)

[0265] According to any one of (1) to (5) of the optical detection device, wherein, The inter-pixel isolation section has a fixed charge film on the side surface of the trench. (7)

[0267] According to the optical detection device in (6), wherein, The straight portion of the inter-pixel isolation section has a fixed charge film on the side, top, and bottom surfaces of the trench. (8)

[0269] The photodetector according to any one of (6) to (7) further includes a fixed charge film on the second surface of the semiconductor substrate, wherein, The fixed charge film on the side surface of the groove in each of the first and second cross sections is connected to the fixed charge film on the second surface. (9)

[0271] The light detection device according to any one of (1) to (8) further includes: The uneven structure on the second surface of a semiconductor substrate. (10)

[0273] According to any one of (1) to (9) of the optical detection device, wherein, A fixed charge film is embedded in the recess of the uneven structure. (11)

[0275] According to any one of (1) to (10) of the optical detection device, wherein, The uneven structure is set on the semiconductor region of the vertical section. (12)

[0277] According to any one of (1) to (11) of the optical detection device, wherein, The inter-pixel isolation section has at least a fixed charge film and an insulating film. (13)

[0279] According to any one of (1) to (12) of the optical detection device, wherein, The inter-pixel isolation section has at least a fixed charge film and a transparent electrode. (14)

[0281] The light detection device according to any one of (1) to (13) further includes: An insulating film is formed on the second surface of the semiconductor substrate, wherein... The insulating film is connected to the insulating film inside the groove of each of the first and second cross sections. (15)

[0283] The light detection device according to any one of (1) to (13) further includes: A transparent electrode is located on the second surface of the semiconductor substrate, wherein... The transparent electrode is connected to the transparent electrode inside the groove of each of the first and second cross sections. (16)

[0285] According to any one of (1) to (15) of the optical detection device, wherein, Each pixel includes two photoelectric conversion units. (17)

[0287] According to any one of (1) to (16) of the optical detection device, wherein, The inter-pixel isolation portion also includes a third intersection at a position different from the first and second intersections, and In the cross-sectional view, the third intersection has a trench structure that isolates the semiconductor substrate from the first surface to the second surface of the semiconductor substrate, and the second surface is disposed on the opposite side of the first surface. (18)

[0289] According to any one of (1) to (17) of the optical detection device, wherein, In the cross-sectional view, all intersections of the inter-pixel isolation portion include trench structures that isolate the semiconductor substrate from the first surface to the second surface of the semiconductor substrate, with the second surface disposed on the opposite side of the first surface. (19)

[0291] According to any one of (1) to (18) of the optical detection device, wherein, The light detection device includes an on-chip lens shared by four pixels arranged in a 2×2 configuration, and The depth of the groove structure in the straight section of the inter-pixel isolation section differs between the inter-pixel isolation section at the boundary of the shared unit of the shared on-chip lens and the inter-pixel isolation section inside the shared unit. (20)

[0293] According to the optical detection device of (19), wherein, The depth of the groove structure in the straight section of the inter-pixel isolation section is shorter in the inter-pixel isolation section inside the shared unit than in the inter-pixel isolation section at the boundary of the shared unit of the shared on-chip lens. (twenty one)

[0295] According to any one of (1) to (20) of the optical detection device, wherein, The light detection device includes an on-chip lens shared by four pixels arranged in a 2×2 configuration, and The material composition embedded in the inter-pixel isolation portion differs between the inter-pixel isolation portion at the boundary of the shared unit of the shared on-chip lens and the inter-pixel isolation portion inside the shared unit. (twenty two)

[0297] According to the optical detection device of (21), wherein, The inter-pixel isolation portion at the boundary of the shared unit includes a fixed charge film, a first insulating material, and a second insulating material. The first insulating material and the second insulating material have different refractive indices. The inter-pixel insulation portion inside the shared unit includes a fixed charge film and a first insulating material with a higher refractive index from the first insulating material and the second insulating material, but does not include a second insulating material with a lower refractive index from the first insulating material and the second insulating material. (twenty three)

[0299] According to any one of (1) to (22) of the optical detection device, wherein, In the cross-sectional view, the straight portion of the inter-pixel isolation portion includes: a first trench structure extending from a first surface side of the semiconductor substrate to a predetermined depth, a second trench structure extending from a second surface side of the semiconductor substrate to a predetermined depth, and a semiconductor region that is part of the semiconductor substrate. (twenty four)

[0301] According to the optical detection device in (23), wherein, The second surface of the semiconductor substrate is a light-incident surface on which light is incident, and the second surface is disposed on the side opposite to the first surface forming the pixel transistor. The inter-pixel isolation portion includes shallow trench isolation in a region on the first surface of the first trench structure. (25)

[0303] According to any one of (23) to (24) of the optical detection device, wherein, The second surface of the semiconductor substrate is a light-incident surface on which light is incident, and the second surface is disposed on the opposite side of the first surface on which the pixel transistor is formed. The fixed charge film and the insulating film are embedded in each of the first trench structure and the second trench structure. The fixed charge film inside the second trench structure is connected to the fixed charge film on the second surface, and The insulating film inside the second trench structure is connected to the insulating film on the second surface. (26)

[0305] According to the optical detection device of (25), wherein, The material of the fixed charge film is any one of hafnium oxide, aluminum oxide, zirconium dioxide, or tantalum oxide, and The insulating film is made of SiO2 or a composite material containing SiO2 as the main component. (27)

[0307] According to any one of (23) to (26) of the optical detection device, wherein, The material composition embedded inside the first trench structure and the material composition embedded inside the second trench structure are different from each other. (28)

[0309] According to any one of (23) to (27) of the optical detection device, wherein, An area where the first trench structure and the second trench structure overlap is formed in a depth direction perpendicular to the second surface of the semiconductor substrate. (29)

[0311] According to any one of (23) to (28) of the optical detection device, wherein, The width of the second trench structure is greater than the width of the first trench structure. (30)

[0313] According to any one of (23) to (29) of the optical detection device, wherein, In the cross-sectional view, the first trench structure is positioned between the two second trench structures. (31)

[0315] An electronic device, comprising: The optical detection device includes: A pixel array unit, wherein multiple pixels are arranged on a semiconductor substrate along row and column directions, wherein... The pixel array unit has inter-pixel isolation portions disposed between the pixels. In the planar view, the inter-pixel isolation portion has a first intersection, a second intersection, and a straight portion located between the first intersection and the second intersection. In the cross-sectional view, both the first and second intersections have trench structures that isolate the semiconductor substrate from its first surface to its second surface, with the second surface disposed on the opposite side of the first surface. In the cross-sectional view, the vertical portion has a semiconductor region and a trench structure that are part of a semiconductor substrate. (32)

[0317] A light detection device, characterized in that it comprises: A pixel array unit, wherein multiple pixels are arranged on a semiconductor substrate along row and column directions, wherein... The pixel array unit has inter-pixel isolation portions disposed between the pixels. In the planar view, the inter-pixel isolation portion has a first intersection, a second intersection, and a straight portion located between the first intersection and the second intersection. In the cross-sectional view, both the first and second intersections have a structure that penetrates from the first surface of the semiconductor substrate to the second surface of the semiconductor substrate, with the second surface arranged on the opposite side of the first surface. In the cross-sectional view, the straight portion has a structure that does not penetrate the semiconductor substrate.

[0318] Reference Symbol List

[0319] 1. Optical detection device

[0320] 2 pixels

[0321] PD photodiode

[0322] 3-pixel array unit

[0323] 21 Semiconductor substrate

[0324] 22 Wiring Layer

[0325] 23 Fixed charge film

[0326] 24 Insulating film

[0327] 25 Color Filters

[0328] 26-pixel inter-pixel light-blocking film

[0329] 27 on-plate lenses

[0330] 41 P-type semiconductor region

[0331] 42 N-type semiconductor region

[0332] 43-pixel isolation section

[0333] 43A Intersection

[0334] 43B Straight section

[0335] 44 Fixed charge film

[0336] 45 Insulating film

[0337] 46 air gap

[0338] 47 P-type semiconductor region

[0339] 211 Anti-reflective section

[0340] 221 Transparent Electrode

[0341] 222 Transparent Electrode

[0342] 301 Electronic Equipment

[0343] 303 Optical Detection Device

[0344] 401 High Refractive Index Film

[0345] 421 First trench

[0346] 422, 422A Second Trench

[0347] 422B Microgrooves

[0348] 422C Second groove.

Claims

1. A light detection device, comprising: A pixel array unit, wherein multiple pixels are arranged on a semiconductor substrate along row and column directions, wherein... The pixel array unit has inter-pixel isolation portions between pixels. In the plan view, the inter-pixel isolation portion has a first intersection portion, a second intersection portion, and a straight portion located between the first intersection portion and the second intersection portion. In the cross-sectional view, both the first and second intersections have trench structures that isolate the semiconductor substrate from its first surface to its second surface. The second surface is disposed on the opposite side of the first surface. In the cross-sectional view, the straight portion has a semiconductor region and a trench structure that are part of the semiconductor substrate.

2. The optical detection device according to claim 1, wherein, The second surface of the semiconductor substrate is a light-incident surface on which light is incident, and the second surface is disposed on the opposite side of the first surface forming the pixel transistor. The semiconductor region of the straight portion is formed on the second surface side of the semiconductor substrate.

3. The optical detection device according to claim 1, wherein, The semiconductor region includes a second conductivity type semiconductor region, the conductivity type of which is opposite to that of the first conductivity type semiconductor region constituting the charge accumulation region of the photoelectric conversion section of each pixel.

4. The optical detection device according to claim 1, wherein, The semiconductor region is also formed between the inter-pixel isolation portion and the photoelectric conversion portion.

5. The optical detection device according to claim 1, wherein, The inter-pixel isolation portion has an STI in the region on the first surface side of the semiconductor substrate.

6. The optical detection device according to claim 1, wherein, The inter-pixel isolation portion has a fixed charge film on the side surface of the trench.

7. The optical detection device according to claim 6, wherein, The straight portion of the inter-pixel isolation portion has the fixed charge film on the side surface, top surface, and bottom surface of the trench.

8. The photodetector according to claim 6, further comprising a fixed charge film on the second surface of the semiconductor substrate, wherein, A fixed charge film on the side surface of the groove of each of the first and second intersections is connected to a fixed charge film on the second surface.

9. The optical detection device according to claim 1, further comprising: The uneven structure on the second surface of the semiconductor substrate.

10. The optical detection device according to claim 9, wherein, A fixed charge film is embedded in the recess of the uneven structure.

11. The optical detection device according to claim 9, wherein, The uneven structure is disposed on the semiconductor region of the straight portion.

12. The optical detection device according to claim 1, wherein, The inter-pixel isolation portion has at least a fixed charge film and an insulating film.

13. The optical detection device according to claim 1, wherein, The inter-pixel isolation portion has at least a fixed charge film and a transparent electrode.

14. The optical detection device according to claim 1, further comprising: An insulating film is provided on the second surface of the semiconductor substrate, wherein... The insulating film is connected to the insulating film inside the trench of each of the first and second intersections.

15. The optical detection device according to claim 1, further comprising: A transparent electrode is disposed on the second surface of the semiconductor substrate, wherein, The transparent electrode is connected to the transparent electrode inside the trench of each of the first and second intersections.

16. The optical detection device according to claim 1, wherein, Each pixel packet includes two photoelectric conversion units.

17. The optical detection device according to claim 1, wherein, The inter-pixel isolation portion also includes a third intersection portion at a position different from the first intersection portion and the second intersection portion, and In the cross-sectional view, the third intersection has a trench structure that isolates the semiconductor substrate from the first surface to the second surface of the semiconductor substrate, the second surface being disposed on the opposite side of the first surface.

18. The optical detection device according to claim 1, wherein, In the cross-sectional view, all intersections of the inter-pixel isolation portion include a trench structure that isolates the semiconductor substrate from the first surface to the second surface of the semiconductor substrate, the second surface being disposed on the opposite side of the first surface.

19. The optical detection device according to claim 1, wherein, The light detection device includes an on-chip lens shared by four pixels arranged in a 2×2 configuration, and The depth of the groove structure in the straight portion of the inter-pixel isolation portion differs between the inter-pixel isolation portion at the boundary of the shared unit sharing the on-chip lens and the inter-pixel isolation portion inside the shared unit.

20. The optical detection device according to claim 19, wherein, The depth of the groove structure of the straight portion of the inter-pixel isolation portion is shorter in the inter-pixel isolation portion inside the shared unit than in the inter-pixel isolation portion at the boundary of the shared unit sharing the on-chip lens.

21. The optical detection device according to claim 1, wherein, The light detection device includes an on-chip lens shared by four pixels arranged in a 2×2 configuration, and The material composition embedded in the inter-pixel isolation portion differs between the inter-pixel isolation portion at the boundary of the shared unit sharing the on-chip lens and the inter-pixel isolation portion inside the shared unit.

22. The optical detection device according to claim 21, wherein, The inter-pixel isolation portion at the boundary of the shared unit includes a fixed charge film, a first insulating material, and a second insulating material, wherein the first insulating material and the second insulating material have different refractive indices. The inter-pixel insulation portion inside the shared unit includes a fixed charge film and the first insulating material with a higher refractive index among the first insulating material and the second insulating material, but does not include the second insulating material with a lower refractive index among the first insulating material and the second insulating material.

23. The optical detection device according to claim 1, wherein, In the cross-sectional view, the straight portion of the inter-pixel isolation portion includes: a first trench structure extending from a first surface side of the semiconductor substrate to a predetermined depth, a second trench structure extending from a second surface side of the semiconductor substrate to a predetermined depth, and the semiconductor region that is part of the semiconductor substrate.

24. The optical detection device according to claim 23, wherein, The second surface of the semiconductor substrate is a light-incident surface on which light is incident, and the second surface is disposed on the opposite side of the first surface forming the pixel transistor. The inter-pixel isolation portion includes shallow trench isolation in a region on the first surface of the first trench structure.

25. The optical detection device according to claim 23, wherein, The second surface of the semiconductor substrate is a light-incident surface on which light is incident, and the second surface is disposed on the opposite side of the first surface forming the pixel transistor. A fixed charge film and an insulating film are embedded in each of the first trench structure and the second trench structure. The fixed charge film inside the second trench structure is connected to the fixed charge film on the second surface, and The insulating film inside the second trench structure is connected to the insulating film on the second surface.

26. The optical detection device according to claim 25, wherein, The material of the fixed charge film is any one of hafnium oxide, aluminum oxide, zirconium dioxide, or tantalum oxide, and The insulating film is made of SiO2 or a composite material containing SiO2 as the main component.

27. The optical detection device according to claim 23, wherein, The material composition embedded inside the first trench structure and the material composition embedded inside the second trench structure are different from each other.

28. The optical detection device according to claim 23, wherein, An area where the first trench structure and the second trench structure overlap is provided in a depth direction perpendicular to the second surface of the semiconductor substrate.

29. The optical detection device according to claim 23, wherein, The width of the second trench structure is greater than the width of the first trench structure.

30. The optical detection device according to claim 23, wherein, In the cross-sectional view, the first trench structure is disposed between the two second trench structures.

31. An electronic device, comprising: The optical detection device includes: A pixel array unit, wherein multiple pixels are arranged on a semiconductor substrate along row and column directions, wherein... The pixel array unit has inter-pixel isolation portions disposed between pixels. In the plan view, the inter-pixel isolation portion has a first intersection portion, a second intersection portion, and a straight portion located between the first intersection portion and the second intersection portion. In the cross-sectional view, both the first and second intersections have trench structures that isolate the semiconductor substrate from its first surface to its second surface. The second surface is disposed on the opposite side of the first surface. In the cross-sectional view, the straight portion has a semiconductor region and a trench structure that are part of the semiconductor substrate.

32. A light detection device, characterized in that, include: A pixel array unit, wherein multiple pixels are arranged on a semiconductor substrate along row and column directions, wherein... The pixel array unit has inter-pixel isolation portions disposed between pixels. In the plan view, the inter-pixel isolation portion has a first intersection portion, a second intersection portion, and a straight portion located between the first intersection portion and the second intersection portion. In the cross-sectional view, both the first intersection and the second intersection have a structure that extends from the first surface of the semiconductor substrate through the semiconductor substrate to the second surface of the semiconductor substrate, with the second surface arranged on the opposite side of the first surface. In the cross-sectional view, the straight portion has a structure that does not penetrate the semiconductor substrate.

Images