JP2010193073A - Rear surface irradiation type imaging device, method of manufacturing same and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging device in which a pixel for focus detection can be loaded even when a pixel becomes small, and to provide a method of manufacturing the imaging device, and an imaging apparatus with the imaging device. <P>SOLUTION: In a rear surface irradiation type imaging device 111 in which the plurality of pixels are two-dimensionally arrayed and disposed, the pixel 211 for focus detection is included together with the pixel 210 for imaging in the plurality of pixels. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a back-illuminated image sensor, a method for manufacturing the back-illuminated image sensor, and an imaging apparatus using the image sensor.

  A surface-illuminated imaging device having a pair of focus detection pixels in an area of approximately the same size as one imaging pixel is known as a conventional technique (for example, Patent Document 1).

JP 2000-305010 A

  In the conventional front-illuminated image sensor as described in Patent Document 1, since a wiring for reading a signal from the photoelectric conversion unit must be formed on the incident light side of the light receiving unit, the light receiving opening is the wiring. It is necessary to set while avoiding the above, and the opening for making the light incident on the light receiving portion becomes narrow. For this reason, in the case of a focus detection pixel that needs to have a light receiving aperture (a pair of light receiving apertures) that is smaller than a normal imaging pixel, it becomes difficult to mount the focus detection pixel as the pixel size is reduced. There is a problem.

According to a first aspect of the present invention, in the back-illuminated imaging device in which a plurality of pixels are arranged two-dimensionally, the plurality of pixels include a pixel for focus detection together with a pixel for imaging.
According to a fifteenth aspect of the present invention, there is provided a back-illuminated image pickup device manufacturing method comprising: a P-type epitaxial layer forming step for forming a P-type epitaxial layer on a surface of a substrate; and a photoelectric conversion for forming a photoelectric conversion portion on the surface of the P-type epitaxial layer. Part forming step, wiring layer forming step for forming a wiring layer on the photoelectric conversion portion, substrate removing step for removing the substrate from the P-type epitaxial layer, and a light shielding film on the surface of the P-type epitaxial layer from which the substrate is removed A light shielding film forming step to be formed; a transparent film-color filter forming step for forming a transparent film and a color filter on the light shielding film; and a microlens forming step for forming a microlens on the transparent film and the color filter. It is characterized by.

  According to the present invention, it is possible to mount a focus detection pixel even if the pixel is downsized.

It is a figure which shows the structure of the electronic camera of one embodiment. It is a figure which shows the focus detection area | region on the imaging screen set to the scheduled image formation surface of an interchangeable lens. It is a figure which shows the Bayer arrangement | sequence of a color filter. It is a figure which shows the detailed structure of an image pick-up element. It is a figure which shows the structure of an imaging pixel. It is a figure which shows the structure of a focus detection pixel. It is a figure for demonstrating the focus detection method by a pupil division system. It is a figure which shows the basic pixel structure of an image pick-up element. It is a figure for demonstrating the wiring contained in one pixel. It is a figure which shows the wiring of a wiring layer. It is a figure for demonstrating the manufacturing method of an image pick-up element. It is a figure for demonstrating the manufacturing method of an image pick-up element. It is a figure for demonstrating the manufacturing method of an image pick-up element.

  An embodiment in which the present invention is applied to an electronic camera as an imaging apparatus will be described. FIG. 1 is a diagram illustrating a configuration of an electronic camera according to an embodiment. An electronic camera 101 according to an embodiment includes an interchangeable lens 102 and a camera body 103, and the interchangeable lens 102 is attached to a mount portion 104 of the camera body 103.

  The interchangeable lens 102 includes lenses 105 to 107, a diaphragm 108, a lens drive control device 109, and the like. The lens 106 is for zooming, and the lens 107 is for focusing. The lens drive control device 109 includes a CPU and its peripheral components, and performs drive control of the focusing lens 107 and the diaphragm 108. Further, the lens drive control device 109 detects the positions of the zooming lens 106, the focusing lens 107 and the diaphragm 108, and transmits lens information and receives camera information by communication with the control device of the camera body 103. Do.

  On the other hand, the camera body 103 includes an image sensor 111, a camera drive control device 112, a memory card 113, an LCD driver 114, an LCD 115, an eyepiece lens 116, and the like. The image sensor 111 is disposed on the planned image plane (plan focal plane) of the interchangeable lens 102, captures the subject image formed by the interchangeable lens 102, and outputs an image signal. An imaging pixel (hereinafter simply referred to as an imaging pixel) is two-dimensionally arranged in the imaging element 111, and a portion corresponding to the focus detection position in the imaging element 111 is replaced with an imaging pixel (hereinafter referred to as a focus detection pixel). A column (simply called focus detection pixels) is incorporated.

  The camera drive control device 112 includes a CPU and its peripheral components, and controls the drive of the image sensor 111, processing of the captured image, focus detection and focus adjustment of the interchangeable lens 102, control of the diaphragm 108, display control of the LCD 115, lens drive control. Communication with the apparatus 109, sequence control of the entire camera, and the like are performed. The camera drive control device 112 communicates with the lens drive control device 109 via an electrical contact 117 provided on the mount unit 104.

  The memory card 113 is an image storage that stores captured images. The LCD 115 is used as a display of a liquid crystal viewfinder (EVF: electronic viewfinder), and a photographer can visually recognize a captured image displayed on the LCD 115 via an eyepiece lens 116.

  The subject image that passes through the interchangeable lens 102 and is imaged on the image sensor 111 is photoelectrically converted by the image sensor 111, and the image output is sent to the camera drive control device 112. The camera drive control device 112 calculates the defocus amount at the focus detection position based on the output of the focus detection pixel, and sends this defocus amount to the lens drive control device 109. In addition, the camera drive control device 112 sends an image signal generated based on the output of the imaging pixel to the LCD driver 114 and displays it on the LCD 115 and also stores it in the memory card 113.

  The lens drive control device 109 detects the positions of the zooming lens 106, the focusing lens 107, and the diaphragm 108, and calculates lens information based on the detected positions, or a lens corresponding to the detected position from a lookup table prepared in advance. Information is selected and sent to the camera drive controller 112. The lens drive control device 109 calculates a lens drive amount based on the defocus amount received from the camera drive control device 112, and drives and controls the focusing lens 107 based on the lens drive amount.

  The image sensor 111 is a back-illuminated 4TR-CMOS (Complementary Metal Oxide Semiconductor) sensor. The 4TR-CMOS sensor includes a photoelectric conversion unit and four transistors including a transfer gate transistor, a source follower transistor, a row selection transistor, and a reset transistor. Details will be described later.

  FIG. 2 shows a focus detection area on the imaging screen G set on the planned imaging plane of the interchangeable lens 102. The focus detection areas G1 to G5 are set on the imaging screen G, and the focus detection pixels of the imaging element 111 are linearly arranged in the longitudinal direction of the focus detection areas G1 to G5 on the imaging screen G. That is, the focus detection pixel row on the image sensor 111 samples the images of the focus detection areas G1 to G5 in the subject image formed on the shooting screen G. The photographer manually selects an arbitrary focus detection area from the focus detection areas G1 to G5 according to the shooting composition.

  FIG. 3 shows an arrangement of color filters installed in the image sensor 211. A Bayer array color filter shown in FIG. 3 is installed on the imaging pixels arranged in a two-dimensional array on the substrate of the imaging element 111. 3 shows an arrangement of color filters for four pixels (2 × 2) of image pickup pixels. An image pickup pixel unit having the color filter arrangement for four pixels is two-dimensionally developed on the image pickup device 111. To do. In the Bayer array, two pixels having a G (green) filter are arranged at diagonal positions, and a pair of pixels having a B (blue) filter and an R (red) filter are arranged at diagonal positions orthogonal to the G filter pixels. Be placed. Therefore, in the Bayer array, the density of green pixels is higher than the density of red pixels and blue pixels.

  FIG. 4 is a front view showing a detailed configuration of the image sensor 111. FIG. 4 is an enlarged view of the periphery of one focus detection area on the image sensor 111. The image sensor 111 includes an imaging pixel 210 and a focus detection pixel 211 for focus detection.

  FIG. 5A is a front view of the imaging pixel 210. FIG.5 (b) is AA sectional drawing of Fig.5 (a). The imaging pixel 210 includes the microlens 10, the microlens fixing layer 11, the color filter 12, the planarization layer 13, the light shielding film 14 </ b> A, the semiconductor layer 16, and the wiring layer 17. On one surface of the semiconductor layer 16, a photoelectric conversion unit 15a and a channel stop unit 15b are formed.

  The microlens 10 collects the light that has reached the surface of the imaging pixel 210 and applies it to the photoelectric conversion unit 15a. The microlens fixing layer 11 fixes the microlens 10 to the color filter 12. The color filter 12 is a resin layer that transmits light in a specific wavelength range, and is obtained by dispersing a pigment corresponding to each color (for example, R, G, B) in the resin, or each color (for example, R, G, B). The resin is colored with a dye corresponding to). The planarization layer 13 is a layer for planarizing the surface after forming the light shielding film 14A in a manufacturing process described later (see FIG. 12B) and before forming the color filter 12.

  The light shielding film 14A is a film for shielding light in the vicinity of the channel stop 15b, and prevents noise and color mixing. The photoelectric conversion unit 15a photoelectrically converts the reached light and accumulates signal charges. The channel stop unit 15b is formed at a boundary portion between the two imaging pixels 210, and prevents signal charges generated in the photoelectric conversion unit 15a from entering the surrounding pixels. The wiring layer 17 includes wirings such as a signal output line, a power supply line, a reset control line, a transfer gate control line, and a row selection control line, which will be described later. Details of the wiring will be described later.

  FIG. 6A is a front view of the focus detection pixel 211. FIG.6 (b) is BB sectional drawing of Fig.6 (a). The focus detection pixel 211 includes the microlens 10, the microlens fixing layer 11, the transparent film 18, the planarization layer 13, the light shielding film 14 </ b> B, the semiconductor layer 16, and the wiring layer 17. On one surface of the semiconductor layer 16, a photoelectric conversion unit 15a and a channel stop unit 15b are formed. The microlens 10, the microlens fixing layer 11, the planarization layer 13, the photoelectric conversion unit 15 a, the channel stop unit 15 b, and the wiring layer 17 have the same functions as the imaging pixel 210, and thus the description thereof is omitted.

  The light shielding film 14B is formed so as to be opened so that incident light strikes the right half or the left half of the photoelectric conversion unit 15a shown in FIG. The focus detection pixels 211a in which light enters the right half of the photoelectric conversion unit 15a and the focus detection pixels 211b in which light enters the left half of the photoelectric conversion unit 15a are alternately arranged. The defocus amount is calculated by comparing the output distribution of the focus detection pixel 211a with the output distribution of the focus detection pixel 211b. The transparent film 18 is a resin layer that transmits light of all wavelengths in the visible light region.

  Next, the focus detection method will be described with reference to FIG. In the embodiment of the present invention, the focus is detected by a so-called pupil division method. FIG. 7 is a diagram illustrating an output distribution of the focus detection pixel 211 when the interchangeable lens 102 is out of focus. A curve 21 is a curve showing the output distribution of the focus detection pixel 211a. A curve 22 is a curve showing the output distribution of the focus detection pixel 211b. The focus detection pixels 211a and the focus detection pixels 211b are alternately arranged. Since the curve 21 is shifted to the right side of the curve 22, it can be seen that the position of the focus detection pixel 211 is the rear pin.

  By multiplying the image shift amount of the two output distributions 21 and 22 by a predetermined conversion coefficient, the current image plane relative to the planned image plane (the focus detection position corresponding to the position of the microlens 10 on the planned image plane) The deviation (defocus amount) of the imaging plane) can be calculated. When the interchangeable lens 102 is in focus, the curve 21 and the curve 22 coincide.

The basic pixel configuration of the image sensor 111 will be described with reference to FIG. As described above, the imaging device 111 is a back-illuminated 4TR-CMOS sensor, and the basic pixel 300 includes the photoelectric conversion unit 33, the charge-voltage conversion unit 34, the transfer gate transistor 32, the source follower transistor 35, the row. The selection transistor 36 and the reset transistor 31 are four transistors. The basic pixel 300 is connected to the signal output line V _OUT , the power supply line Vdd, the reset control line φR, the transfer gate control line φTG, and the row selection control line φRS.

  The reset transistor 31 resets the charge-voltage converter 34 to the initial potential. The transfer gate transistor 32 transfers the photoelectrically converted signal charge to the charge / voltage converter 34. The photoelectric conversion unit 33 photoelectrically converts the light that has arrived as described above, and accumulates signal charges. The charge-voltage converter 34 is a stray capacitance that converts a signal charge into a potential, and this stray capacitance is generated by a diode that functions as a capacitor. The source follower transistor 35 amplifies the potential change of the charge-voltage conversion unit 34 due to the accumulated charge. The row selection transistor 36 performs switching for selecting the basic pixel 300 to which a signal is transferred.

The signal output line _VOUT is a wiring for transferring a signal output from the basic pixel 300 and is connected to the drain of the row selection transistor 36. The power supply line Vdd is a wiring that supplies power for amplifying the potential change of the charge-voltage conversion unit 34 and is connected to the source of the reset transistor 31. The reset control line φR is a wiring for controlling on / off of the reset transistor 31 and is connected to the gate of the reset transistor 31. The transfer gate control line φTG is a wiring for controlling the transfer of signal charges to the charge-voltage converter 34 and is connected to the gate of the transfer gate transistor 32. The row selection control line φRS is a wiring for controlling on / off of the row selection transistor 36 and is connected to the gate of the row selection transistor 36.

With reference to FIG. 9, a wiring included in one pixel will be described. As shown in FIG. 9, the image sensor 111 includes a signal output line V _OUT , a power supply line Vdd, a reset control line φR, a transfer gate control line φTG, and a row selection control line φRS in one row of pixels arranged in parallel. There are two each, and each column has four signal output lines _VOUT . Thereby, the signals of the plurality of basic pixels 300 can be read at a time, and the detection speed of the image sensor 111 can be increased. Accordingly, a wiring included in one pixel 51 indicated by a dotted line in FIG. 9 includes a basic pixel 300 of another pixel that is not connected to the basic pixel 300 in addition to a wiring connected to the basic pixel 300. The wiring to connect is also included. For this reason, the number of wirings included in one pixel increases.

The wiring in the wiring layer 17 of the image sensor 111 will be described with reference to FIG. FIG. 10A is a plan view when the wiring of the wiring layer 17 is viewed from the microlens 10 side. FIG.10 (b) is CC sectional drawing of Fig.10 (a). As shown in FIGS. 10A and 10B, the wiring of the wiring layer is formed in a lattice shape over three layers. As viewed from the photoelectric conversion unit 15a, four signal output lines _VOUT and two bias lines Vb are formed in the first layer, and two power supply lines Vdd and 2 are formed in the second layer. A reset control line φR is formed. In the third layer, two transfer gate control lines φTG and two row selection control lines φRS are formed. The bias line Vb is formed to prevent interference.

  As shown in FIG. 10B, the wiring layer 17 is formed on the opposite side of the light incident side with respect to the photoelectric conversion unit 15a, so that it is not subject to the restriction (constraint) of the position of the photoelectric conversion unit 15a. Wiring can be freely formed. That is, in the present embodiment, the wiring can be formed also in a region overlapping the projection when the light receiving region of the photoelectric conversion unit 15a is projected from the light receiving surface side of the image sensor 111. On the other hand, when the imaging element is a surface irradiation type, since the wiring layer is formed on the light incident side with respect to the photoelectric conversion unit 15a, it is necessary to form a wiring so as not to overlap the light receiving region of the photoelectric conversion unit. .

  In the present embodiment, since the wiring layer 17 of the image sensor 111 is not limited by the position of the photoelectric conversion unit 15a, the line width of the wiring can be widened to increase the signal transmission efficiency.

  Next, with reference to FIGS. 11-13, the manufacturing method of the image pick-up element 111 in embodiment of this invention is demonstrated. FIGS. 11 to 13 show the focus detection pixel 211 in the image sensor 111 in particular.

  As shown in FIG. 11A, a P-type epitaxial layer 61 is formed on a semiconductor substrate 60, a diffusion layer is formed on the surface of the P-type epitaxial layer 61, and a photoelectric conversion unit 15a, a channel stop unit 15b, Another element (not shown) constituting a transistor or the like is formed. This P-type epitaxial layer 61 corresponds to the semiconductor layer 16. Next, as shown in FIG. 11B, the formation of the silicon oxide film by CVD and the formation of the aluminum (Al) wiring by sputtering are repeated to form the wiring layer 17 on the P-type epitaxial layer 61. Then, as shown in FIG. 11C, a support substrate 62 is bonded on the wiring layer 17.

  As shown in FIG. 12A, the semiconductor substrate 60 is removed by etching. Next, as shown in FIG. 12B, a light shielding film 14B made of aluminum (Al) is formed on the surface from which the semiconductor substrate 60 has been removed by sputtering. And as shown in FIG.12 (c), in order to planarize the surface, after apply | coating the resin which forms the planarization layer 13 uniformly on the light shielding film 14B, the transparent film 18 is formed. For example, the transparent film 18 is formed through resin coating, drying of the applied resin, pattern exposure, and development processing.

  As shown in FIG. 13A, after applying a resin for forming the microlens fixing layer 11 on the transparent film 18, the resin for forming the microlens 10 is applied, and the desired shape is obtained by well-known lithography. The microlens base 63 is formed by patterning. Next, as shown in FIG. 13B, the microlens base 63 is heat-formed into a hemispherical shape using a hot plate or the like to form the microlens 10. Then, the support substrate 62 is removed, and the image sensor 111 is completed.

  In the image pickup pixel 210 portion, the color filter 12 corresponds to the transparent film 18, and the light shielding film 14A is formed to correspond to the light shielding film 14B. The color filter 12 and the transparent film 18 are formed in the same process, and the light shielding film 14A and the light shielding film 14B are formed in the same process.

  If the microlens 10, the color filter 12, and the transparent film 18 can be formed in the imaging device, the microlens fixing layer 11 and the planarizing layer 13 may be omitted.

According to the embodiment described above, the following operational effects can be obtained.
(1) The imaging device 111 is a back-illuminated type, and the focus detection pixel 211 is included together with the imaging pixel 210 in a plurality of pixels arranged two-dimensionally. Thereby, since the substantial opening area of the light shielding film 14B of the focus detection pixel 211 can be increased, the focus detection pixel can be mounted even if the pixel is downsized.

  In addition, since the wiring layer is disposed on the side opposite to the light incident side of the photoelectric conversion unit 15a, compared to the surface irradiation type in which the wiring layer is disposed on the light incident side of the photoelectric conversion unit 15a, Since the distance from the microlens 10 to the photoelectric conversion unit 15a can be shortened by at least the wiring layer, the focus detection accuracy can be increased.

(2) The focus detection pixel 211 has the photoelectric conversion unit 15a on one surface and the semiconductor layer 16 having the other surface as a light receiving surface, and a light-shielding film that blocks a part of the light incident on the photoelectric conversion unit 15a. 14B and a wiring _VOUT that reads a signal from the photoelectric conversion unit 15a, the wiring _VOUT is formed on one surface side of the semiconductor layer 16, and the light shielding film 14B is formed on the other surface side of the semiconductor layer 16. It was to so. As a result, the microlens 10 and the photoelectric conversion unit 15a are compared with the case of a front-illuminated imaging device in which a wiring for reading a signal from the photoelectric conversion unit must be formed between the microlens and the photoelectric conversion unit. Can be shortened (shallow), so that the focus detection accuracy can be increased.

(3) The focus detection pixel 211 does not read out the signal from the photoelectric conversion unit 15a, and includes a wiring for reading out the signal from the photoelectric conversion unit in another pixel on one surface side of the semiconductor layer 16. Thereby, wiring can be formed so as to read out signals of the plurality of basic pixels 300 at a time, and the detection speed of the image sensor 111 can be increased.

(4) The wiring overlaps with the projection when the light receiving area of the photoelectric conversion unit 15a is projected from the light receiving surface side of the image sensor 111. As a result, a large number of wirings can be formed in the focus detection pixel 211 or the width of the wiring can be increased without increasing the number of wiring layers. On the other hand, when the imaging device is a front-illuminated type, it is necessary to form wiring so as not to overlap with the light receiving region of the photoelectric conversion unit. Therefore, when many wirings are formed, the number of wiring layers increases, The width may not be increased.

(5) Since the degree of freedom of the shape of the light shielding films 14A and 14B is high, by examining the shape of the light shielding films 14A and 14B, it is possible to improve the separation performance between pixels of the imaging pixels, crosstalk between the pixels, light leakage. It is possible to suppress the line crawl phenomenon due to sticking out.

(6) A P-type epitaxial layer 61 is formed on the surface of the semiconductor substrate 60, a photoelectric conversion unit 15a is formed on the surface of the P-type epitaxial layer 61, a wiring layer 17 is formed on the photoelectric conversion unit 15a, and a P-type epitaxial layer is formed. The semiconductor substrate 60 is removed from the layer 61, the light shielding films 14A and 14B are formed on the surface of the P-type epitaxial layer 61 from which the semiconductor substrate 60 is removed, and the transparent film 18 and the color filter 12 are formed on the light shielding films 14A and 14B. The imaging element 111 is manufactured by forming the microlens 10 on the transparent film 18 and the color filter 12. Thereby, a backside illumination type image sensor can be manufactured efficiently.

The above embodiment can be modified as follows.
(1) The light shielding films 14A and 14B may have functions of electrodes and wiring. Thereby, the function as an image pick-up element can be improved. For example, it is possible to perform high-speed readout of pixels or to enable independent pixel control. The functions provided to the light shielding films 14A and 14B are, for example, a signal line (signal output line V _OUT ), a power supply line Vdd, a control line (reset control line φR, transfer gate control line φTG, row selection control line φRS), bias The light shielding films 14A and 14B may have any function of the line Vb. Thereby, when the number of wirings is increased in order to read a plurality of pixels at the same time or to control the plurality of pixels at the same time, an increase in the number of wiring layers 17 can be suppressed.

  Further, by providing the light shielding films 14A and 14B with the functions of electrodes and wiring, the degree of freedom of separation of signal lines, control lines, power supply lines, and bias lines can be increased. Among signal lines, control lines, power supply lines, and bias lines, there are some that should be formed away from other electrodes and wiring. By providing the light shielding films 14A and 14B with such a wiring function and forming other wirings in the wiring layer 17, the wirings can be formed apart from each other. For example, interference may occur when the signal line is formed near the control line. Therefore, the signal line can be formed away from the control line by providing the light shielding films 14A and 14B with the function of one of the signal line and the control line and forming the other line in the wiring layer 17. it can.

  In this case, a through-hole penetrating the P-type epitaxial layer 61 is formed by etching or the like, and the photoelectric conversion unit 15a and other elements formed on the surface of the P-type epitaxial layer 61 and the light-shielding film are formed using this through-hole. Wiring for electrically connecting 14A and 14B may be formed.

(2) Although the number of wiring layers of the wiring layer 17 is three in the above embodiment, the number of wiring layers is not limited to three. For example, the number of wiring layers of the wiring layer 17 may be increased up to 10 to increase the number of pixels that can be read or controlled simultaneously. Unlike the front-illuminated image sensor, the distance between the microlens 10 and the photoelectric conversion unit 15a does not increase even if the number of wiring layers is increased. In addition, the number of wiring layers in the wiring layer 17 may be reduced to two to limit the function and reduce the manufacturing cost.

(3) The light shielding films 14A and 14B may be floated, or a voltage may be applied to the light shielding films 14A and 14B by biasing the light shielding films 14A and 14B or fixing the light shielding films 14A and 14B to a power source. It may be. Thereby, load capacity can be increased / decreased or interference can be prevented.

(4) Although aluminum (Al) having a high reflectance is used as the material of the light shielding films 14A and 14B, a metal having a predetermined reflectance or lower than the reflectance of aluminum (Al) may be used. For example, tungsten (W), titanium (Ti), or tin (Sn) may be used as the material of the light shielding films 14A and 14B. Thereby, it is possible to prevent the light reflected from the light shielding films 14A and 14B from entering the photoelectric conversion unit 15a and the image quality of the image captured by the electronic camera 101 from being deteriorated. Further, instead of tungsten (W), titanium (Ti) or tin (Sn), the reflectance of visible light of tungsten (W) or less, the reflectance of titanium (Ti) or less of visible light, or tin (Sn) of You may make it use the metal which has the reflectance below the reflectance of visible light.

  Further, oxides or nitrides that do not transmit light having a predetermined reflectance lower than that of aluminum (Al) may be used as the light shielding films 14A and 14B. For example, it has a reflectance below the reflectance of tungsten (W) visible light, below the reflectance of titanium (Ti) visible light, or below the reflectance of tin (Sn) visible light, and does not transmit visible light. Oxides and nitrides may be used. Examples of the oxide include tungsten oxide, titanium oxide, and tin oxide. Examples of the nitride include tungsten nitride, titanium nitride, and tin nitride. The light shielding films 14A and 14B are formed by CVD or sputtering after the semiconductor substrate 60 is removed (see FIG. 12A).

(5) Although aluminum (Al) having a high reflectance is used as the material of the light shielding films 14A and 14B, a resin that does not transmit light below a predetermined reflectance lower than the reflectance of aluminum (Al) is used. Also good. For example, a light curable resin containing a black pigment such as titanium black or carbon black, or a light curable resin colored with a black dye may be used as the material of the light shielding films 14A and 14B. Thereby, it can suppress that the light which reflected light-shielding film 14A, 14B injects into the photoelectric conversion part 15a. Also, instead of a photo-curing resin containing a black pigment such as titanium black or carbon black, or a photo-curing resin colored with a black dye, the reflectance of tungsten (W) is less than the visible light reflectance of titanium (Ti). You may make it use the resin which has the reflectance below the reflectance of visible light, or below the reflectance of the visible light of tin (Sn), and does not permeate | transmit visible light. The light shielding films 14A and 14B are formed, for example, after removing the semiconductor substrate 60 (see FIG. 12A) and then applying resin, drying the applied resin, pattern exposure, and development processing.

(6) A metal film having a predetermined reflectance lower than that of aluminum (Al) may be formed on the surfaces of the light shielding films 14A and 14B. For example, a tungsten (W), titanium (Ti), or tin (Sn) film may be formed on the surfaces of the light shielding films 14A and 14B. Thereby, it can suppress that the light which reflected light-shielding film 14A, 14B injects into the photoelectric conversion part 15a. Further, instead of tungsten (W), titanium (Ti) or tin (Sn), the reflectance of visible light of tungsten (W) or less, the reflectance of titanium (Ti) or less of visible light, or tin (Sn) of A metal film having a reflectance equal to or lower than the reflectance of visible light may be formed on the surfaces of the light shielding films 14A and 14B.

  Further, an oxide or nitride film that does not transmit light having a predetermined reflectance lower than the reflectance of aluminum (Al) may be formed on the surfaces of the light shielding films 14A and 14B. For example, it has a reflectance below the reflectance of tungsten (W) visible light, below the reflectance of titanium (Ti) visible light, or below the reflectance of tin (Sn) visible light, and does not transmit visible light. An oxide or nitride film may be formed on the surface of the light shielding films 14A and 14B. Examples of the oxide include tungsten oxide, titanium oxide, and tin oxide. Examples of the nitride include tungsten nitride, titanium nitride, and tin nitride. These films are formed by CVD or sputtering after the light shielding films 14A and 14B are formed (see FIG. 12B).

(7) A resin film that does not transmit light at a predetermined reflectance lower than that of aluminum (Al) may be formed on the surfaces of the light shielding films 14A and 14B. For example, a photo-curing resin film containing a black pigment such as titanium black or carbon black, or a photo-curing resin film colored with a black dye may be formed on the surfaces of the light shielding films 14A and 14B. Thereby, it can suppress that the light which reflected light-shielding film 14A, 14B injects into the photoelectric conversion part 15a. Also, instead of a photo-curing resin containing a black pigment such as titanium black or carbon black, or a photo-curing resin colored with a black dye, the reflectance of tungsten (W) is less than the visible light reflectance of titanium (Ti). A resin film having a reflectance equal to or lower than the reflectance of visible light or the visible light reflectance of tin (Sn) and not transmitting visible light may be formed on the surfaces of the light shielding films 14A and 14B. These films are formed, for example, after forming the light-shielding films 14A and 14B (see FIG. 12B), and then applying resin, drying the applied resin, pattern exposure, and development processing.

(8) You may make it form the film | membrane of the material below the above-mentioned predetermined reflectance on the surface of light shielding film 14A, 14B below the above-mentioned predetermined reflectance. Thereby, it can further suppress that the light which reflected light-shielding film 14A, 14B injects into the photoelectric conversion part 15a.

(9) The image sensor 111 is a 4TR-CMOS sensor. However, the image sensor 111 is not limited to a 4TR-CMOS sensor as long as it is a back-illuminated image sensor. For example, another CMOS sensor or a CCD (Charge Coupled Device) may be used.

  It is also possible to combine one or a plurality of embodiments and modifications. It is possible to combine the modified examples in any way.

  The above description is merely an example, and the present invention is not limited to the configuration of the above embodiment.

DESCRIPTION OF SYMBOLS 10 Microlens 11 Microlens fixed layer 12 Color filter 13 Flattening layer 14A, 14B Light shielding film 15a, 33 Photoelectric conversion part 15b Channel stop part 16 Semiconductor layer 17 Wiring layer 18 Transparent film 31 Reset transistor 32 Transfer gate transistor 34 Charge voltage conversion Part 35 Source follower transistor 36 Row selection transistor 60 Semiconductor substrate 61 P-type epitaxial layer 62 Support substrate 101 Electronic camera 102 Interchangeable lens 111 Imaging element 210 Imaging pixels 211, 211a, 211b Focus detection pixel 300 Basic pixel

Claims (15)

In the backside-illuminated image sensor in which a plurality of pixels are arranged two-dimensionally,
The plurality of pixels include a focus detection pixel as well as an imaging pixel. In the backside illuminated image sensor according to claim 1,
The focus detection pixel includes a semiconductor layer having a photoelectric conversion portion on one surface and a light receiving surface on the other surface, a light-shielding film that blocks a part of light incident on the other surface, Wiring for reading out signals from the photoelectric conversion unit,
The wiring is formed on the one surface side of the semiconductor layer,
The back-illuminated image pickup device, wherein the light shielding film is formed on the other surface side of the semiconductor layer. The back-illuminated image sensor according to claim 2,
The focus detection pixel further includes a wiring for reading a signal from the photoelectric conversion unit in another pixel on the one surface side of the semiconductor layer without reading a signal from the photoelectric conversion unit. Backside illuminated image sensor. The back-illuminated image sensor according to claim 2 or 3,
The backside-illuminated image sensor, wherein the wiring overlaps with a projection when a light-receiving region of the photoelectric conversion unit is projected from the light-receiving surface side of the backside-illuminated image sensor. The backside illumination type imaging device according to any one of claims 1 to 4,
A voltage applied to the light shielding film is a backside illumination type image pickup device. The backside illumination type imaging device according to any one of claims 2 to 5,
The back-illuminated image sensor, wherein the light shielding film is made of a metal having a reflectance equal to or lower than a reflectance that is lower than that of aluminum. The backside illumination type imaging device according to any one of claims 2 to 5,
The backside-illuminated imaging device, wherein the light-shielding film is made of an oxide or a nitride having a reflectance equal to or lower than a reflectance that is lower than that of aluminum and not transmitting light. The backside illumination type imaging device according to any one of claims 2 to 5,
The back-illuminated image sensor, wherein the light shielding film is made of a resin having a reflectance equal to or lower than a predetermined reflectance and not transmitting light. The backside illumination type imaging device according to any one of claims 2 to 5,
A back-illuminated imaging device, wherein a metal film having a reflectance equal to or lower than a reflectance of aluminum is formed on a surface of the light shielding film. The backside illumination type imaging device according to any one of claims 2 to 5,
A back-illuminated imaging device, wherein an oxide or nitride film that has a reflectance equal to or lower than a reflectance of aluminum and does not transmit light is formed on the surface of the light shielding film. The backside illumination type imaging device according to any one of claims 2 to 5,
A back-illuminated imaging device, wherein a film of a resin having a reflectance equal to or lower than a reflectance of aluminum and not transmitting light is formed on a surface of the light shielding film. The backside illuminated imaging device according to any one of claims 6 to 11,
The back-illuminated image sensor, wherein the predetermined reflectance is a reflectance of tin. In the backside illuminated image sensor according to claim 1,
The focus detection pixel includes a semiconductor layer having a photoelectric conversion portion and a transistor on one surface and a light receiving surface on the other surface, and a light shielding film that blocks a part of light incident on the other surface. And at least one of a signal line for reading a signal from the photoelectric conversion unit, a power supply line for supplying power for amplifying the signal from the photoelectric conversion unit, and a control line for controlling the transistor ,
The wiring is formed on the one surface side of the semiconductor layer,
The light shielding film is formed on the other surface side of the semiconductor layer, and has a function of reading a signal from the photoelectric conversion unit, a function of supplying power for amplifying the signal from the photoelectric conversion unit, and the A backside-illuminated image sensor having at least one function of controlling a transistor.   An imaging apparatus comprising the backside illumination type imaging device according to claim 1. A P-type epitaxial layer forming step of forming a P-type epitaxial layer on the surface of the substrate;
A photoelectric conversion part forming step of forming a photoelectric conversion part on the surface of the P-type epitaxial layer;
A wiring layer forming step of forming a wiring layer on the photoelectric conversion portion;
A substrate removal step of removing the substrate from the P-type epitaxial layer;
A light shielding film forming step of forming a light shielding film on the surface of the P-type epitaxial layer from which the substrate is removed;
A transparent film-color filter forming step of forming a transparent film and a color filter on the light shielding film;
And a microlens formation step of forming a microlens on the transparent film and the color filter.

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