JP2019091947A - Solid state image pickup device - Google Patents

Abstract

To provide a solid state image pickup device capable of suppressing the occurrence of white scratch caused by static electricity.SOLUTION: According to one embodiment, a solid state image pickup device is provided. The solid state image pickup device have a semiconductor layer, a micro-lens, a conductive anti-reflection film and an anti-low refractive index film. A plurality of photoelectric conversion elements are provided on the semiconductor layer. The micro-lens is provided on each light-receiving surface side of a plurality of photoelectric conversion elements. The conductive anti-reflection film is provided on a surface of the micro-lens, and its refractive index is higher than that of the micro-lens. The anti-low refractive index film is provided on the surface of the conductive anti-reflection film, and its refractive index is higher than that of the air and lower than that of the micro-lens.SELECTED DRAWING: Figure 4

Description

  Embodiments of the present invention relate to a solid-state imaging device.

  Conventionally, a solid-state imaging device includes a plurality of photoelectric conversion elements that photoelectrically convert incident light, and microlenses that are provided on the light receiving surface side of each photoelectric conversion element and condense the incident light onto the photoelectric conversion elements. In addition, the solid-state imaging device includes an anti-reflection film that is formed on the surface of each of the microlenses and that prevents reflection on the surface of the microlenses.

  In the above-described solid-state imaging device, the device may be cleaned after an antireflective film is formed on the surface of the microlens. In such a case, static electricity is generated on the surface of the antireflective film by washing, and the charge is charged. The charge may be detected as a dark current when the captured image is output, and may appear as a white scratch in the imaging pixel.

JP 2012-84608 A

  One object of the present invention is to provide a solid-state imaging device capable of suppressing the occurrence of white damage caused by static electricity.

  According to one embodiment, a solid state imaging device is provided. The solid-state imaging device includes a semiconductor layer, a microlens, a conductive antireflective film, and a low refractive index preventing film. The semiconductor layer is provided with a plurality of photoelectric conversion elements. The microlens is provided on each light receiving surface side of the plurality of photoelectric conversion elements. The conductive antireflective film is provided on the surface of the micro lens, and the refractive index is higher than the refractive index of the micro lens. The low refractive index antireflective film is provided on the surface of the conductive antireflective film, and the refractive index is higher than the refractive index of air and lower than the refractive index of the microlens.

FIG. 1 is a block diagram showing a schematic configuration of a digital camera provided with a solid-state imaging device according to an embodiment. FIG. 2 is a block diagram showing a schematic configuration of the solid-state imaging device according to the embodiment. FIG. 3 is an explanatory view in cross section of the pixel array according to the embodiment. FIG. 4 is an explanatory view showing an enlargement of a schematic configuration of the pixel array according to the embodiment. FIG. 5 is an explanatory view showing the transmittance of the microlens provided with the antireflective film according to the embodiment. FIG. 6 is an explanatory view based on a cross-sectional view of the manufacturing process of the solid-state imaging device according to the embodiment. FIG. 7 is an explanatory view based on a cross-sectional view of the manufacturing process of the solid-state imaging device according to the embodiment. FIG. 8 is an explanatory view by a cross sectional view of the manufacturing process of the solid-state imaging device according to the embodiment.

  Hereinafter, a solid-state imaging device and a method of manufacturing the solid-state imaging device according to the embodiment will be described in detail with reference to the accompanying drawings. The present invention is not limited by this embodiment.

  FIG. 1 is a block diagram showing a schematic configuration of a digital camera 1 provided with a solid-state imaging device 14 according to the embodiment. As shown in FIG. 1, the digital camera 1 includes a camera module 11 and a post-processing unit 12.

  The camera module 11 includes an imaging optical system 13 and a solid-state imaging device 14. The imaging optical system 13 takes in light from a subject and forms a subject image. The solid-state imaging device 14 captures an object image formed by the imaging optical system 13, and outputs an image signal obtained by imaging to the post-processing unit 12. The camera module 11 is applied to an electronic device such as a camera-equipped mobile terminal other than the digital camera 1, for example.

  The post-processing unit 12 includes an image signal processor (ISP) 15, a storage unit 16, and a display unit 17. The ISP 15 performs signal processing of an image signal input from the solid-state imaging device 14. The ISP 15 performs high image quality processing such as noise removal processing, defective pixel correction processing, resolution conversion processing, and the like.

  Then, the ISP 15 outputs the image signal after signal processing to the storage unit 16, the display unit 17, and a signal processing circuit 21 (see FIG. 2) described later included in the solid-state imaging device 14 in the camera module 11. The image signal fed back from the ISP 15 to the camera module 11 is used for adjustment and control of the solid-state imaging device 14.

  The storage unit 16 stores an image signal input from the ISP 15 as an image. In addition, the storage unit 16 outputs the image signal of the stored image to the display unit 17 according to the user's operation or the like. The display unit 17 displays an image according to the image signal input from the ISP 15 or the storage unit 16. The display unit 17 is, for example, a liquid crystal display.

  Next, the solid-state imaging device 14 included in the camera module 11 will be described with reference to FIG. FIG. 2 is a block diagram showing a schematic configuration of the solid-state imaging device 14 according to the embodiment. As shown in FIG. 2, the solid-state imaging device 14 includes an image sensor 20 and a signal processing circuit 21.

  Here, a so-called back-illuminated CMOS (Complementary Metal Oxide Semiconductor) image sensor in which the wiring layer is formed on the side opposite to the side on which the incident light is incident on the photoelectric conversion element that photoelectrically converts the incident light. Will be described.

  Note that the image sensor 20 according to the embodiment is not limited to the back side illumination type CMOS image sensor, and may be any image sensor such as a front side illumination type CMOS image sensor or a CCD (Charge Coupled Device) image sensor Good.

  The image sensor 20 includes a peripheral circuit 22 and a pixel array 23. The peripheral circuit 22 also includes a vertical shift register 24, a timing control unit 25, a CDS (correlated double sampling) 26, an ADC (analog-digital conversion unit) 27, and a line memory 28, which are mainly configured by analog circuits. Be done.

  The pixel array 23 is provided in the area where the light from the imaging optical system 13 of the image sensor 20 is incident. In the solid-state imaging device 14, the pixel array 23 is an imaging region. In the pixel array 23, a plurality of photoelectric conversion elements corresponding to respective pixels of a captured image are arranged in a two-dimensional array (matrix) in the horizontal direction (row direction) and the vertical direction (column direction).

  Each photoelectric conversion element is provided in the semiconductor layer, and light corresponding to each photoelectric conversion element is received according to the amount of light received through the color filter and the microlens stacked on the light incident side of the semiconductor layer. It is photoelectrically converted into an amount of charge and accumulated as a signal charge indicating the luminance of each pixel.

  The timing control unit 25 is a processing unit that outputs a pulse signal as a reference of operation timing to the vertical shift register 24, the CDS 26, the ADC 27, and the line memory 28. The vertical shift register 24 outputs to the pixel array 23 a selection signal for sequentially selecting, on a row basis, the photoelectric conversion elements for reading out the signal charges from the plurality of photoelectric conversion elements arranged two-dimensionally in an array (matrix). It is a processing unit.

  The pixel array 23 outputs, from the photoelectric conversion element to the CDS 26, the signal charge stored in each photoelectric conversion element selected on a row basis by the selection signal input from the vertical shift register 24 as a pixel signal indicating the luminance of each pixel. Do. The configuration of the pixel array 23 will be described later with reference to FIGS. 3 and 4.

  The CDS 26 is a processing unit that removes noise from the pixel signal input from the pixel array 23 by correlated double sampling and outputs the noise to the ADC 27. The ADC 27 is a processing unit that converts an analog pixel signal input from the CDS 26 into a digital pixel signal and outputs the digital pixel signal to the line memory 28. The line memory 28 is a processing unit that temporarily holds pixel signals input from the ADC 27 and outputs the pixel signals to the signal processing circuit 21 for each row of photoelectric conversion elements in the pixel array 23.

  The signal processing circuit 21 is a processing unit that performs predetermined signal processing on pixel signals input from the line memory 28 and outputs the processed signal to the post-processing unit 12 and is mainly configured by a digital circuit. The signal processing circuit 21 performs signal processing such as lens shading correction, flaw correction, and noise reduction processing on the pixel signal, for example.

  As described above, in the image sensor 20, the plurality of photoelectric conversion elements arranged in the pixel array 23 photoelectrically convert incident light into signal charges of an amount according to the amount of received light, and the peripheral circuit 22 The image pickup is performed by reading out the signal charges accumulated in the pixel as a pixel signal.

  Further, the image sensor 20 condenses the light from the imaging optical system 13 by the micro lens, and makes the condensed light enter the photoelectric conversion element through the color filter.

  Here, a general microlens has a single-layer anti-reflection film formed on the surface, and such anti-reflection film prevents reflection on the surface of the microlens, and the amount of light incident on the light receiving surface of the photoelectric conversion element To increase the

  By the way, in a solid-state imaging device, after an antireflective film is formed on the surface of a microlens, the surface of the device may be cleaned using pure water or the like. In such a case, static electricity is generated on the surface of the antireflective film by washing, and the charge is charged. The charge may be detected as a dark current when the captured image is output, and may appear as a white scratch in the imaging pixel.

  Therefore, in the solid-state imaging device 14 according to the present embodiment, a two-layer antireflection film in which a conductive antireflection film and a low refractive index antireflection film are stacked from the microlens side is provided on the surface of the microlens. Then, the solid-state imaging device 14 suppresses the occurrence of the white flaw by releasing the charge charged by static electricity in the low refractive index antireflective film of the outer layer by the conductive antireflective film of the inner layer. Hereinafter, the pixel array 23 in which the occurrence of the white flaw due to the static electricity is suppressed will be described with reference to FIGS. 3 and 4.

  FIG. 3 is an explanatory view showing a schematic configuration as viewed in cross section of the pixel array 23 according to the embodiment. FIG. 4 is an explanatory view showing an enlarged schematic configuration of the pixel array 23 according to the embodiment. Here, for convenience, the side on which the light 9 of the pixel array 23 is incident is referred to as the upper side, and the side opposite to the side on which the light 9 of the pixel array 23 is incident is the lower side.

  As shown in FIG. 3, the pixel array 23 includes a multilayer wiring layer 35 provided on the support substrate 31 via the adhesive layer 32, and a photoelectric conversion element 38. The multilayer interconnection layer 35 includes an interlayer insulating film 34, and the read gate 3 and the multilayer interconnection 33 provided inside the interlayer insulating film 34. The multilayer interconnection 33 is used to read out negative signal charges (electrons) photoelectrically converted by the photoelectric conversion element 38 and to transmit a drive signal to each circuit element.

  The photoelectric conversion element 38 includes, for example, phosphorus (P) or the like inside the P-type Si layer 36 doped with a P-type low concentration impurity such as boron (B) and the P-type Si layer 36. The photodiode is formed by the PN junction with the N-type Si region 37 doped with the N-type high concentration impurity.

  The photoelectric conversion elements 38 are two-dimensionally arrayed in an array (matrix) in the P-type Si layer 36. Then, the photoelectric conversion element 38 photoelectrically converts the light 9 incident from the end face on the side opposite to the interface with the multilayer wiring layer 35 into a signal charge according to the amount of light received and accumulates it in the N-type Si region 37 .

  In addition, the pixel array 23 includes the P-type hole accumulation region 5 on the light receiving surface of the photoelectric conversion element 38. The hole accumulation region 5 accumulates positive charges (holes) present in the N-type Si region 37.

  That is, in the P-type hole accumulation region 5, positive charges recombine with negative charges resulting from the interface state generated in the vicinity of the light receiving surface in the N-type Si region 37, regardless of the presence or absence of incident light. It is a region that reduces the negative charge that occurs and causes dark current.

  In addition, the pixel array 23 includes the first Si oxide film 40 on the light receiving surface of the P-type hole accumulation region 5. The first Si oxide film 40 terminates dangling bonds generated on the light receiving surface side end face of the N-type Si region 37. Thereby, the pixel array 23 reduces dark current by suppressing an increase in interface state due to dangling bonds.

  Furthermore, the pixel array 23 includes the Si nitride film 6, the color filter 70, and the microlens 71 sequentially stacked on the light receiving surface of the P-type hole accumulation region 5.

  The Si nitride film 6 functions as an anti-reflection film that prevents reflection of incident light passing through the color filter 70. In addition, the color filter 70 transmits incident light of any one of the three primary colors of red, green, and blue, for example.

  The microlens 71 is a plano-convex lens, and condenses incident light incident on the pixel array 23 on the photoelectric conversion element 38. The microlens 71 is formed using a high refractive index material having a refractive index n1 of 1.6 to 1.7. In the present embodiment, the microlens 71 is formed of an organic resin having a refractive index n1 of, for example, 1.62.

  In addition, the pixel array 23 includes the antireflection film 8 formed of two layers in which the conductive antireflection film 80 and the low refractive index antireflection film 81 are laminated on the surface of the microlens 71 from the microlens 71 side.

  Specifically, this will be described with reference to FIG. As shown in FIG. 4, the microlens 71 according to the embodiment includes the two-layer antireflection film 8 in which the conductive antireflection film 80 and the low refractive index antireflection film 81 are stacked on the surface from the microlens 71 side. . The film thickness d 1 of the conductive antireflection film 80 is larger than the film thickness d 2 of the low refractive index antireflection film 81. Specifically, the film thickness d1 of the conductive antireflection film 80 is, for example, 20 to 40 nm thicker than the film thickness d2 of the low refractive index antireflection film 81.

  The conductive antireflective film 80 is a metal oxide film having a refractive index n 2 higher than the refractive index n 1 of the microlens 71. Specifically, the conductive antireflective film 80 is a metal oxide film having a refractive index n2 of 1.6 to 2.7. As such a metal oxide film, for example, a titanium oxide (TiO) film can be mentioned.

  Further, the conductive antireflective film 80 is connected to the ground GND via a pad connected by a wiring pattern or the like (not shown) in order to ground the low refractive index antireflective film 81 electrostatically charged to the outside. Therefore, the conductive anti-reflection film 80 plays a role of guiding the low-refractive-index anti-reflection film 81 electrostatically charged to the pad connected to the ground GND. As a result, the charge charged on the low refractive index antireflective film 81 by static electricity flows through the conductive antireflective film 80 and the pad to the ground GND.

The low refractive index antireflective film 81 is a silicon oxide film in which the refractive index n3 is higher than the refractive index of air (n0 = 1.0) and lower than the refractive index n1 of the microlens 71. Specifically, the low refractive index antireflective film 81 is a silicon oxide film having a refractive index n3 of 1.2 to 1.6. As such a silicon oxide film, for example, silicon dioxide (SiO ₂ ) can be mentioned.

  Here, the transmittance of the microlens 71 provided with the above-described two-layer antireflection film 8 will be described with reference to FIG. FIG. 5 is an explanatory view showing the transmittance of the microlens 71 provided with the antireflection film 8 according to the embodiment.

  In FIG. 5, the vertical axis represents the transmittance [%], and the horizontal axis represents the wavelength [nm]. Further, in the graph of FIG. 5, the thick line indicates the transmittance of the microlens 71 having the antireflection film 8 consisting of two layers, the thin line indicates the transmittance of the microlens 71 having the low refractive index antireflection film 81, and the dashed-dotted line indicates The transmittances of the microlenses 71 not provided with the anti-reflection film 8 are shown.

  In this transmittance evaluation test, the microlens 71 is an organic resin having a refractive index n1 of 1.62, the conductive antireflection film 80 is a tantalum oxide film having a refractive index n2 of 1.97, and a low refractive index antireflection As the film 81, a silicon oxide film having a refractive index n3 of 1.37 was used.

  As shown in FIG. 5, the microlens 71 provided with the antireflection film 8 consisting of two layers has a transmittance higher than that of the microlens 71 provided with the low refractive index antireflection film 81 and has a short wavelength range ( It can be seen that the wavelength reaches approximately 99% from 450 nm) to the long wavelength band (700 nm).

  This is because the refractive index n2 is 1.97 and the refractive index n1 of the microlens 71 is between the microlens 71 having a refractive index n1 of 1.62 and the low refractive index antireflection film 81 having a refractive index n3 of 1.37. This is because the conductive anti-reflection film 80 higher than that is interposed.

  More specifically, light 9 incident on the conductive antireflective film 80 through the low refractive index antireflective film 81 has a refractive index n 2 of the conductive antireflective film 80 higher than that of the microlens 71, Total reflection occurs at the interface between the conductive antireflective film 80 and the microlens 71. However, since the light 9 has a refractive index n 2 of the conductive antireflective film 80 higher than that of the low refractive index antireflective film 81, the light 9 has the conductive antireflective film 80 and the low refractive index antireflective film 81. It causes total reflection again at the interface. Then, return light due to total reflection enters the microlens 71 without being totally reflected at the interface between the conductive antireflection film 80 and the microlens 71.

  From such a thing, it is thought that the transmittance of the microlens 71 provided with the antireflection film 8 composed of two layers is higher than the transmittance of the microlens 71 provided with the low refractive index antireflection film 81. That is, the microlens 71 provided with the two-layer antireflection film 8 has a high transmittance, and also has a function of removing charges charged by static electricity.

  Further, the micro lens 71 provided with the anti-reflection film 8 consisting of two layers has the film thickness d1 of the electroconductive anti-reflection film 80 thicker than the film thickness d2 of the low refractive index anti-reflection film 81, so that the electro-conductive anti-reflection film 80 is formed. Multiple reflection at the interface between the film 80 and the microlens 71 is suppressed.

  The solid-state imaging device 14 according to the above-described embodiment has a two-layer antireflection film 8 in which the conductive antireflection film 80 and the low refractive index antireflection film 81 are stacked on the surface of the microlens 71 from the microlens 71 side. Equipped with

  As a result, the solid-state imaging device 14 can release the electrostatically charged charges on the low refractive index antireflective film 81 of the outer layer by the conductive antireflective film 80 of the inner layer. Therefore, the solid-state imaging device 14 electrostatically charges the surface of the low refractive index antireflective film 81 by cleaning even when the antireflective film 8 is formed on the surface of the microlens 71 and then the device surface is cleaned using pure water or the like. Charge can flow through conductive antireflective film 80 and the pad to ground GND. Therefore, the solid-state imaging device 14 can suppress the occurrence of white flaws caused by static electricity.

  In addition, the solid-state imaging device 14 according to the above-described embodiment includes the micro lens 71 provided with the antireflection film 8 formed of two layers of the conductive antireflection film 80 and the low refractive index antireflection film 81. As a result, the solid-state imaging device 14 has a high transmittance of the microlens 71 provided with the two-layer antireflection film 8 compared to the transmittance of a general one-layer antireflection film. The amount of light 9 incident on the photoelectric conversion element 38 is increased, and the light receiving sensitivity of the pixel is improved.

  Next, a method of manufacturing the solid-state imaging device 14 including the method of forming the pixel array 23 described above will be described with reference to FIGS. The method of manufacturing the portion other than the pixel array 23 in the solid-state imaging device 14 is the same as that of a general CMOS image sensor. Therefore, hereinafter, a method of manufacturing the pixel array 23 portion in the solid-state imaging device 14 will be described.

  6-8 is a cross-sectional schematic diagram which shows the manufacturing process of the solid-state imaging device 14 which concerns on embodiment. As shown in FIG. 6A, when the pixel array 23 is manufactured, a P-type Si layer 36 is formed on a semiconductor substrate 30 such as a Si wafer. At this time, for example, a P-type Si layer 36 is formed by epitaxially growing a Si layer doped with a P-type low concentration impurity such as boron on the semiconductor substrate 30. The P-type Si layer 36 may be formed by ion implantation of a low concentration P-type impurity into the inside of the Si wafer and annealing treatment.

  Subsequently, annealing is performed by ion-implanting an N-type high concentration impurity such as phosphorus into the P-type Si layer 36 from the upper surface side of the P-type Si layer 36 to perform annealing treatment. The N-type Si regions 37 are two-dimensionally arranged in a matrix.

  Thus, a PN junction is formed by the P-type Si layer 36 and the N-type Si region 37, and the photoelectric conversion element 38 which is a photodiode is formed. Here, the N-type Si region 37 is a charge storage region for storing the photoelectrically converted negative charge, and the bonding surface side to the semiconductor substrate 30 is exposed later to be a light receiving surface of incident light.

  Subsequently, as shown in FIG. 6B, the multilayer wiring layer 35 is formed on the top surface of the photoelectric conversion element 38. In the step of forming the multilayer wiring layer 35, first, the read gate 3 or the like is formed of, for example, polysilicon at a predetermined position on the surface of the P-type Si layer 36. Next, for example, a step of forming an interlayer insulating film 34 such as a Si oxide film, a step of forming a predetermined wiring pattern on the interlayer insulating film 34, and copper (Cu) or the like is embedded in the wiring pattern to form a multilayer wiring. A multilayer wiring layer 35 is formed by repeating the steps of forming 33.

  After that, as shown in FIG. 6C, an adhesive is applied to the upper surface of the multilayer wiring layer 35 to provide the adhesive layer 32, and a support substrate 31 such as a Si wafer is attached to the upper surface of the adhesive layer 32. . Alternatively, the support substrate 31 may be directly bonded to the upper surface of the multilayer wiring layer 35 without using the adhesive layer 32.

  Subsequently, as shown in FIG. 7A, after inverting the top and bottom of the structure shown in FIG. 6C, the semiconductor substrate 30 is viewed from the back surface side (here, the upper surface side) by a grinding device such as a grinder. Grinding is performed to thin the semiconductor substrate 30 to a predetermined thickness.

  After that, the back surface side of the semiconductor substrate 30 is further polished by CMP (Chemical Mechanical Polishing), for example, to expose the back surface (here, the top surface) of the N-type Si region 37. At this time, dangling bonds are generated on the upper surface, which is a polished surface of the N-type Si region 37, to generate an interface state.

  Therefore, first, as shown in FIG. 7B, the first Si oxide film 40 is formed on the light receiving surface of the photoelectric conversion element 38, and dangling bonds produced on the light receiving surface side end face of the N type Si region 37. Terminate. For example, ALD (Atomic Layer Deposition) is used to form the first Si oxide film 40. Next, on the upper part of the P-type Si layer 36, for example, a P-type high concentration impurity such as boron is ion-implanted and annealing is performed to form the hole accumulation region 5.

  Next, as shown in FIG. 7C, the Si nitride film 6 to be an antireflective film is formed on the upper surface of the first Si oxide film 40 by using, for example, the CVD method. Then, as shown in FIG. 8A, the color filter 70 and the micro lens 71 are sequentially formed on the upper surface of the Si nitride film 6.

  Subsequently, as shown in FIG. 8B, a conductive anti-reflection film 80 of a predetermined thickness d1 containing, for example, titanium oxide (TiO) is formed on the upper surface of the microlens 71 using, for example, a sputtering method. Form. The conductive antireflective film 80 is connected to the pad by pattern wiring or the like, and is connected to the ground GND via the pad.

After that, a low refractive index antireflective film 81 having a predetermined thickness d2 (d2 <d1) containing, for example, silicon dioxide (SiO ₂ ) is formed on the upper surface of the conductive antireflective film 80 using, for example, the CVD method. By doing this, the pixel array 23 shown in FIG. 3 is manufactured. Then, after the antireflective film 8 is formed on the surface of the microlens 71, the surface of the solid-state imaging device 14 is cleaned.

  As described above, the solid-state imaging device 14 according to the embodiment is a reflection made of two layers in which the conductive antireflection film 80 and the low refractive index antireflection film 81 are laminated on the surface of the microlens 71 from the microlens 71 side. A protective film 8 is provided.

  As a result, the solid-state imaging device 14 can release the electrostatically charged charges on the low refractive index antireflective film 81 of the outer layer by the conductive antireflective film 80 of the inner layer. Therefore, in the solid-state imaging device 14, even if the surface of the device is cleaned using pure water or the like after the antireflective film 8 is formed on the surface of the microlens 71, the surface of the low refractive index antireflection film 81 is cleaned by static electricity. The charged charge can flow through the conductive antireflective film 80 and the pad to ground GND. Therefore, the solid-state imaging device 14 can suppress the occurrence of white flaws caused by static electricity.

  The solid-state imaging device 14 electrostatically charges the surface of the low refractive index anti-reflection film 81 by contact with the conveyance arm even when the conveyance by the conveyance arm is performed after the antireflective film 8 is formed on the surface of the microlens 71 Charge can flow through conductive antireflective film 80 and the pad to ground GND.

  In the solid-state imaging device 14 described above, the conductive anti-reflection film 80 is connected to the ground GND via the pad, but is not limited to such a form, and may not be connected to the ground GND.

  Even in this embodiment, the electrostatically charged film 80 can widely disperse the charge charged by static electricity remaining in one portion of the low refractive index antireflective film 81 in the formation region of the conductive antireflective film 80. Therefore, it is possible to suppress the occurrence of white damage caused by static electricity.

  In the embodiment described above, the Si layer 36 is P-type and the Si region 37 is N-type, but the pixel array 23 may be configured such that the Si layer 36 is N-type and the Si region 37 is P-type. .

  While certain embodiments of the present invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

  Reference Signs List 1 digital camera 11 camera module 12 post-processing unit 13 imaging optical system 14 solid-state imaging device 15 ISP 16 storage unit 17 display unit 20 image sensor 21 signal processing circuit 22 peripheral circuit 23 pixel array , 24 vertical shift register, 25 timing control unit, 26 CDS, 27 ADC, 28 line memory, 3 read gate, 30 semiconductor substrate, 31 support substrate, 32 adhesive layer, 33 multilayer wiring, 34 interlayer insulating film, 35 multilayer wiring layer , 36 P type Si layer, 37 N type Si region, 38 photoelectric conversion element, 40 first Si oxide film, 5 hole accumulation region, 6 Si nitride film, 70 color filter, 71 micro lens, 8 antireflection Film, 80 conductive antireflective film, 81 Low refractive index anti-reflection film, 9 light

According to one embodiment, a solid state imaging device is provided. The solid-state imaging device includes a semiconductor layer, a microlens, a conductive antireflective film, and a low refractive index preventing film. The semiconductor layer is provided with a plurality of photoelectric conversion elements. The microlens is provided on each light receiving surface side of the plurality of photoelectric conversion elements. Conductive antireflection film is provided on the surface of the microlens, the refractive index is rather higher than the refractive index of the microlens, is grounded. The low refractive index antireflective film is provided on the surface of the conductive antireflective film, and the refractive index is higher than the refractive index of air and lower than the refractive index of the microlens.

Claims (4)

A semiconductor layer provided with a plurality of photoelectric conversion elements;
A microlens provided on each light receiving surface side of the plurality of photoelectric conversion elements;
A conductive antireflective film provided on the surface of the micro lens, wherein the refractive index is higher than the refractive index of the micro lens;
A low refractive index antireflective film provided on the surface of the conductive antireflective film and having a refractive index higher than the refractive index of air and lower than the refractive index of the microlens Imaging device. The conductive antireflective film is
The film thickness is thicker than the film thickness of the said low refractive index anti-reflective film. The solid-state imaging device of Claim 1 characterized by the above-mentioned. The conductive antireflective film is
It is a metal oxide film whose refractive index is 1.6-2.7. The solid-state imaging device according to claim 1 or 2 characterized by things. The low refractive index antireflective film is
The solid-state imaging device according to any one of claims 1 to 3, which is a silicon oxide film having a refractive index of 1.2 to 1.6.

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