WO2018154644A1

WO2018154644A1 - Solid-state image pickup device, fluorescent observation endoscope device, and method for manufacturing solid-state image pickup device

Info

Publication number: WO2018154644A1
Application number: PCT/JP2017/006529
Authority: WO
Inventors: 秀一加藤
Original assignee: オリンパス株式会社
Priority date: 2017-02-22
Filing date: 2017-02-22
Publication date: 2018-08-30

Abstract

This solid-state image pickup device has a first semiconductor substrate having formed therein: a first photoelectric conversion layer, in which first photoelectric conversion elements for photoelectrically converting inputted light are formed; and first wiring layer, in which first wiring is formed, said first wiring layer being formed on a surface on the reverse side of the surface from which light is inputted to the first photoelectric conversion elements. The solid-state image pickup device also has a second semiconductor substrate that is laminated on a surface on the reverse side of the surface from which light is inputted to the first semiconductor substrate, said second semiconductor substrate having formed therein: a second photoelectric conversion layer, in which second photoelectric conversion elements for photoelectrically converting light that has passed through the first semiconductor substrate are formed; and a second wiring layer, in which second wiring is formed. Furthermore, the solid-state image pickup device has: a dielectric multilayer film filter disposed between the first semiconductor substrate and the second semiconductor substrate; a reflecting layer that is formed, in the first photoelectric conversion layer, among the first photoelectric conversion elements by applying a low refractive index material having a lower optical refractive index than the first photoelectric conversion layer; and light transmitting regions that are formed, in the first wiring layer, at positions corresponding to the first photoelectric conversion elements.

Description

Solid-state imaging device, fluorescence observation endoscope apparatus, and method of manufacturing solid-state imaging device

The present invention relates to a solid-state imaging device, a fluorescence observation endoscope apparatus, and a method of manufacturing a solid-state imaging device.

Conventionally, in order to diagnose cancer and the like, a diagnostic method is known in which the presence or absence of a lesion is determined by administering a derivative-labeled antibody (fluorescent drug) called ICG (indocyanine green) in advance to the body of a test subject. ing. ICG is a fluorescent substance having affinity to a lesion such as cancer, and is excited by light in the infrared region to emit fluorescence. And conventionally, various medical systems provided with the function to observe the fluorescence emission of ICG are proposed. For example, an examiner such as a doctor determines the presence or absence of a lesion from the brightness of fluorescence emission observed by a medical system.

In a conventional medical system, as a configuration for observing fluorescence, light in the infrared region such as near infrared light is irradiated as excitation light for exciting ICG, and fluorescence is emitted by the irradiated excitation light It is equipped with a fluorescence observation device for imaging a specific protein of the illuminated lesion.

For example, Patent Document 1 discloses an endoscope apparatus capable of performing observation of fluorescence using excitation light in addition to ordinary observation using visible light. In the endoscope apparatus disclosed in Patent Document 1, visible light and excitation light are irradiated from the tip of the insertion portion onto the subject, and the visible light and the excitation light reflected from the subject are excited by the excitation light. Guides the fluorescence emitted from the ICG to the camera head through the image guide fiber. Then, in the endoscope apparatus disclosed in Patent Document 1, first, visible light, excitation light, and fluorescence guided to the camera head are visible light and excitation light by the dichroic mirror provided in the camera head. And separate into fluorescence and fluorescence. The visible light separated here is imaged by the imaging means. Further, in the endoscope apparatus disclosed in Patent Document 1, the excitation light is removed (cut) from the separated excitation light and fluorescence by the excitation light cut filter provided in the camera head, and only the fluorescence is intensified. It is amplified by the fire and imaged by an imaging means other than the imaging means for visible light.

Generally, there are endoscope apparatuses of the type in which the imaging unit is mounted outside the insertion unit and the type in which the imaging unit is mounted at the distal end of the insertion unit. In an endoscope apparatus of a type in which the imaging unit is mounted on the distal end of the insertion unit, wide-range observation can be performed by bending the distal end of the insertion unit on which the imaging unit is mounted. Become. Here, in order to realize a function of performing a wide-range observation by curving the distal end portion, it is necessary to make the imaging unit mounted on the distal end portion of the insertion portion smaller. However, in the configuration of the endoscope apparatus disclosed in Patent Document 1, that is, in the configuration in which light is separated by the dichroic mirror, by providing a plurality of imaging units, imaging of visible light and fluorescence of each imaging unit Although imaging can be performed simultaneously, the configuration of an imaging system, that is, an imaging unit including a dichroic mirror, a plurality of imaging units, and the like is enlarged. For this reason, it is difficult to mount the configuration of the imaging unit disclosed in Patent Document 1 on the distal end portion of the insertion unit as an imaging unit of an endoscope apparatus having a configuration capable of bending the distal end portion. That is, in the technique of the endoscope apparatus disclosed in Patent Document 1, it is difficult to realize the function of performing a wide-range observation by the configuration in which the distal end portion is curved.

Further, Patent Document 1 has a configuration in which only one imaging unit is mounted at the tip of the insertion portion, and normal observation using visible light and fluorescence observation using excitation light are performed in time series. An endoscopic device is also disclosed. In the endoscope apparatus having a configuration in which only one imaging means is mounted at the tip of the insertion portion disclosed in Patent Document 1, the tip of the insertion portion is limited by a band limiting filter for limiting the wavelength band of the light source. The light to be irradiated to the object to be inspected is switched. More specifically, in the endoscope apparatus disclosed in Patent Document 1, each of a visible light transmission filter for transmitting visible light and an infrared light transmission filter for transmitting infrared light is equally divided into two circles. Visible light or excitation of the light irradiated to the inspection object from the tip of the insertion portion by rotating the band-limited rotation filter arranged to be synchronized with the cycle (frame cycle) captured by the imaging means Switch to light. Thereby, in the endoscope apparatus disclosed in Patent Document 1, imaging of visible light and imaging of fluorescence are performed in time series (alternately) by one imaging unit. If it is such composition, the technique of the endoscope apparatus indicated by patent documents 1 is carried in the tip part of an insertion part as an imaging part of the endoscope apparatus of the composition which can make a tip part curve. be able to.

However, in the configuration of the endoscope apparatus disclosed in Patent Document 1 in which only one imaging means is mounted at the distal end of the insertion portion, imaging means corresponding to each of the separated visible light and the excitation light and the fluorescence As in the configuration in which imaging is performed, imaging of visible light and imaging of fluorescence can not be performed at the same timing. For this reason, in the endoscope apparatus disclosed in Patent Document 1 in which only one imaging means is mounted at the distal end of the insertion portion, for example, an examiner such as a doctor or the like takes an image of visible light and fluorescence When the images are superimposed and presented, a shift may occur at the position of the test object included in the superimposed images due to the difference in timing at which the respective images are captured. The displacement of the position of the object to be inspected appears more prominently in the case where there is a movement in the object to be inspected or the insertion part, for example, in an endoscope apparatus of a surgical system. Further, in the configuration of the endoscope apparatus disclosed in Patent Document 1 in which only one imaging unit is mounted at the tip of the insertion portion, the period (frame period) in which the imaging unit captures an image In order to synchronize, control of the imaging unit becomes complicated.

Therefore, conventionally, for example, as described in Patent Document 2, a first substrate for imaging light in the visible band (visible light) and a first substrate for imaging light in the near infrared range (near infrared light) A stacked imaging device in which two substrates are stacked is proposed. Patent Document 2 discloses a technique for arranging a stacked imaging element at the tip of an endoscope apparatus. In the endoscope apparatus disclosed in Patent Document 2, visible light and excitation light are irradiated to the subject from the tip of the endoscope scope, and the visible light and the excitation light reflected from the subject are excited. The fluorescence emitted from the ICG by excitation with light is incident on the imaging device. Then, in the stacked imaging device disclosed in Patent Document 2, light (excitation light) in the excitation wavelength band is removed (cut) by the optical filter, and visible light is imaged by the first substrate; By imaging only the fluorescence transmitted through the substrate with the second substrate, an image obtained by imaging visible light and an image obtained by imaging fluorescence are simultaneously generated.

From this, by mounting an imaging device (solid-state imaging device) having a stacked configuration as disclosed in Patent Document 2 at the tip, the tip can be curved, and at the same time, visible light It is possible to realize an endoscope apparatus that performs imaging and fluorescence imaging at the same timing. Then, in an endoscope apparatus in which an imaging device (solid-state imaging device) having a stacked structure as disclosed in Patent Document 2 is mounted at the tip, an image obtained by capturing visible light and an image obtained by capturing fluorescence are superimposed. Even in this case, for example, an image such as a doctor can be presented with an image in which no displacement occurs in the position of the subject.

Japanese Patent No. 3962122 Japanese Patent Application Laid-Open No. 2016-058866

By the way, in the endoscope apparatus, for the purpose of reducing the burden on the body of the person to be examined, it is desired to further miniaturize the tip. For this reason, there is also a demand for downsizing of the solid-state imaging device mounted on the tip. However, as disclosed in Patent Document 2, signals (pixel signals) corresponding to light incident on each of the first substrate and the second substrate are output from each of the two stacked substrates. In the solid-state imaging device having the above configuration, an electrode pad (input / output pad) as a terminal for inputting / outputting a signal such as a pixel signal to / from the outside is disposed on each of the first substrate and the second substrate. It is necessary to (form). For this reason, in the stacked solid-state imaging device having the configuration as disclosed in Patent Document 2, the number of electrode pads is doubled as compared with the solid-state imaging device formed of one substrate (single plate). It will

Generally, the mounting area of a small solid-state imaging device has a high proportion depending on the number of electrode pads disposed on the substrate. Therefore, the configuration in which the number of electrode pads is doubled as disclosed in Patent Document 2 causes an increase in the mounting area of the solid-state imaging device. Therefore, in the stacked solid-state imaging device as disclosed in Patent Document 2, the size (area) of each substrate is reduced by reducing the size (area) of the pixels arranged on each substrate. It is conceivable to reduce the mounting area.

However, if the area of the pixels is reduced in the stacked solid-state imaging device having the configuration as disclosed in Patent Document 2, the distance between the respective pixels, that is, the so-called pixel pitch becomes narrow. It is conceivable that no light is incident. This is because in the stacked solid-state imaging device, the second substrate is at a position far from the light incident side, and the fluorescence has a long wavelength, so the influence of diffraction is large and the diffusion of light is fast (light The amount of light diffusion is large). Then, in the stacked solid-state imaging device, if the fluorescence is not efficiently incident on the second substrate, the image quality of the image of the fluorescence to be captured may be degraded.

Here, in the stacked solid-state imaging device as disclosed in Patent Document 2, an example in the case where the pixel pitch is narrowed will be described. FIG. 10 is a diagram showing an example of the structure of the stacked solid-state imaging device and the distribution characteristic of the light intensity. FIG. 10A schematically shows an example of the cross-sectional structure of a region in which pixels are arranged in the stacked solid-state imaging device. More specifically, in (a) of FIG. 10, in the stacked solid-state imaging device 930, a pixel to which an on-chip color filter that transmits light (visible light) in the red (R) Hereinafter, two “R pixels” and two pixels (hereinafter “G pixels”) to which an on-chip color filter for transmitting light (visible light) in the green (G) wavelength band is attached are alternately provided. The vertical structure of the area | region arrange | positioned one by one is shown typically.

Also, in (b) of FIG. 10 and (c) of FIG. 10, the optical simulation of the distribution of light intensity (light intensity) at the corresponding position in the solid-state imaging device 930 shown in (a) of FIG. An example of the result is shown. More specifically, in (b) of FIG. 10 and (c) of FIG. 10, the respective light intensity distributions of the visible light G in the green (G) wavelength band and the fluorescence f of the fluorescence wavelength band are shown. An example of an optical simulation result is shown. In (b) of FIG. 10 and (c) of FIG. 10, the relative magnitude (intensity) of light intensity is shown on the vertical axis, with the pixel pitch on the horizontal axis. The results of the optical simulation shown in (b) in FIG. 10 and (c) in FIG. It is the result of optically simulating the distribution of each light intensity with f.

The solid-state imaging device 930 has a structure in which a first substrate 931 and a second substrate 932 are stacked with a bonding layer 933 interposed therebetween, as shown in FIG. More specifically, in the solid-state imaging device 930, the microlens layer 935, the on-chip color filter layer 934, the first substrate 931, the bonding layer 933, the second, and the light traveling direction are from the light incident side. And the support substrate 936 in this order. Here, the first substrate 931 includes a photoelectric conversion layer 931-1 in which photoelectric conversion elements (light receiving elements) such as photodiodes forming a pixel are disposed (formed), and a circuit formed over the first substrate 931. It is formed by the wiring layer 931-2 in which the wiring for connecting the elements is formed. In the same manner as the first substrate 931, the second substrate 932 also includes a photoelectric conversion layer 932-1 on which a photoelectric conversion element (light receiving element) is disposed (formed) and a circuit formed on the second substrate 932 It is formed by the wiring layer 932-2 in which the wiring for connecting the elements is formed.

First, as shown in FIG. 10B, the visible light G and the fluorescence incident on the G pixel on the surface of the photoelectric conversion layer 931-1 on the light incident side to the first substrate 931, that is, the surface of the silicon substrate. The result of optical simulation of the light intensity distribution of f is confirmed. As shown in (b) of FIG. 10, the distribution of the light intensity of the visible light G on the silicon surface on the light incident side to the photoelectric conversion layer 931-1 is near the center of the position where the G pixel is arranged, that is, , G (peak) at the center position which is the focal point of the microlens corresponding to the G pixel. Further, as shown in (b) of FIG. 10, the light intensity distribution of the fluorescence f on the silicon surface on the light incident side to the photoelectric conversion layer 931-1 is also weaker than that of the visible light G, Similar to the visible light G, it has a peak near the center of the position where the G pixel is disposed. As shown in (b) of FIG. 10, the light intensity of the fluorescent light f is weaker than that of the visible light G because the fluorescent light f is very weak light emitted from the ICG by the excitation light. It is for.

Subsequently, the G pixel is transmitted on the surface (surface of the silicon substrate) of the photoelectric conversion layer 931-1 on the side from which the light incident on the first substrate 931 is transmitted and emitted as shown in (c) of FIG. The results of optical simulation of the distribution of the light intensity of the visible light G and the fluorescence f are confirmed. Note that since the visible light G transmitted without being absorbed by the photoelectric conversion layer 931-1 (silicon substrate) has a weak light intensity, in (c) of FIG. 10, the relative magnitude of the light intensity is The range of intensity (magnitude) is shown enlarged according to the visible light G and the fluorescence f where the light intensity is weak. As shown in (c) of FIG. 10, the distribution of the light intensity of the visible light G on the silicon surface on the side from which the light incident on the photoelectric conversion layer 931-1 is transmitted and emitted is the photoelectric conversion layer 931-1. Similar to the distribution of the light intensity of the visible light G on the silicon surface on the light incident side, it has a peak near the center of the position where the G pixel is disposed. On the other hand, as shown in (c) of FIG. 10, the distribution of the light intensity of the fluorescence f on the silicon surface on the side from which the light incident on the photoelectric conversion layer 931-1 is transmitted and emitted is the photoelectric conversion layer. Unlike the distribution of the light intensity of the fluorescence f on the silicon surface on the light incident side to 931-1, it has a peak near the position where the G pixel is arranged and the position where the R pixel is arranged.

Thus, the fluorescence f is transmitted through the photoelectric conversion layer 931-1 (silicon substrate), and the position where the light intensity distribution peaks is shifted from the vicinity of the center of the position where the pixels are arranged. It was confirmed by optical simulation that the That is, since the diffusion proceeds in the photoelectric conversion layer 931-1 due to the diffraction phenomenon from the time when the fluorescence f having a long wavelength enters from the silicon surface on the light incident side to the photoelectric conversion layer 931-1, it is close The position where the light intensity distribution peaks gradually as the light travels (as the light approaches the wiring layer 931-2) due to the interference with the fluorescence f which has similarly diffused in the (adjacent) pixels, It shifts to the position of the wiring in the wiring layer 931-2. For this reason, most of the fluorescent light f strikes the wiring in the wiring layer 931-2 and is reflected, and can not pass through the wiring layer 931-2 and can not reach the second substrate 932. It was confirmed by simulation.

In the light intensity distribution shown in (c) of FIG. 10, the light intensity distribution of the fluorescent light f has a peak at the silicon surface on the side from which the light incident on the photoelectric conversion layer 931-1 is transmitted and emitted. In the wiring layer 931-2 of the first substrate 931, the wiring layer is overlapped with the region where the wiring is formed. In this case, the fluorescence that has entered the solid-state imaging device 930 and transmitted through the photoelectric conversion layer 931-1 is blocked by the wiring formed in the wiring layer 931-2 of the first substrate 931, and the photoelectric conversion of the second substrate 932 The proportion of fluorescence incident on the photoelectric conversion element (light receiving element) disposed (formed) in the conversion layer 932-1 is significantly reduced. As described above, in the stacked solid-state imaging device in which the pixel pitch is narrowed, the light amount of the fluorescence incident on the photoelectric conversion element (light receiving element) disposed (formed) on the second substrate decreases and the sensitivity to the fluorescence decreases. As described above, the image quality of the fluorescence image captured by the second substrate 932 is degraded.

As described above, when the pixel area is reduced and the pixel pitch is narrowed in order to reduce the mounting area in the stacked solid-state imaging device having the configuration as disclosed in Patent Document 2, it is arranged on the second substrate ( The sensitivity to fluorescence in the formed pixel is reduced, and the resolution of the image of the fluorescence imaged on the second substrate is reduced. Therefore, in the stacked solid-state imaging device, in order to allow the fluorescence having a long wavelength to be transmitted through the first substrate and to be incident on the second substrate even when the light diffuses beyond the diffraction limit. In order to increase the area of the pixel, that is, to increase the pixel pitch. For example, when the pixel pitch is 2 um or less, if the influence of the diffraction of fluorescence is large, the deterioration of the image quality of the image of the fluorescence imaged by the second substrate is within the allowable range, that is, the second substrate In order to make the sensitivity of the photoelectric conversion element (light receiving element) arranged (formed) and the resolution of the captured fluorescence image within the allowable range, it is necessary to make the pixel pitch wider than 2 um.

As described above, in order to realize miniaturization of the stacked solid-state imaging device having the configuration as disclosed in Patent Document 2, in order to secure a region for arranging (forming) the electrode pad on the second substrate Solve the two contradictory problems of narrowing the pixel pitch and widening the pixel pitch so that fluorescence with long wavelength light passes through the first substrate without exceeding the diffraction limit There is a need. For this reason, in the stacked solid-state imaging device having the configuration as disclosed in Patent Document 2, the area (also related to the pixel pitch) of the pixels disposed on each substrate is limited, and the solid-state imaging device is miniaturized Can not be easily realized. For example, in the above-described example, it is impossible to realize a stacked solid-state imaging device in which the pixel pitch is 2 μm or less.

The present invention is made based on the above problems, and is a solid-state imaging device configured to stack a plurality of semiconductor substrates in which photoelectric conversion parts are formed, and to simultaneously image visible light and fluorescence excited by a fluorescent substance. A solid-state imaging device capable of achieving downsizing while suppressing deterioration in image quality of an image obtained by imaging fluorescence, a fluorescence observation endoscope apparatus using the solid-state imaging device, and a method of manufacturing the solid-state imaging device. It is intended to be provided.

According to the first aspect of the present invention, in the solid-state imaging device, the first photoelectric conversion layer in which the first photoelectric conversion element that photoelectrically converts incident light is formed, and the first photoelectric conversion element A first semiconductor substrate on which a first wiring layer is formed on a surface opposite to the surface on which light is incident, and a side on which light is incident on the first semiconductor substrate; A second photoelectric conversion layer in which a second photoelectric conversion element for photoelectrically converting light transmitted through the first semiconductor substrate is formed, and a second wiring is formed. A second semiconductor substrate on which two wiring layers are formed, a dielectric multilayer filter disposed between the first semiconductor substrate and the second semiconductor substrate, and the first photoelectric conversion layer Formed between the first photoelectric conversion elements, wherein the refractive index of light is higher than that of the first photoelectric conversion layer Has a reflecting layer again low refractive index material is formed by filling in the first wiring layer, and a light transmissive region formed at a position corresponding to the first photoelectric conversion element.

According to a second aspect of the present invention, in the solid-state imaging device according to the first aspect, the light transmitting region is formed of a high refractive index material having a light refractive index larger than that of the first wiring layer. It may have a light pipe.

According to a third aspect of the present invention, in the solid-state imaging device according to the first aspect, the first wiring and the outside are formed on the first semiconductor substrate and penetrate the first photoelectric conversion layer. And a penetrating electrode which penetrates the dielectric multilayer filter and electrically connects the first wiring and the second wiring. It is also good.

According to a fourth aspect of the present invention, in the solid-state imaging device according to the third aspect, the power supply supplied to the corresponding electrode pad of the first semiconductor substrate, the ground, and the external of any one of the master clocks. The signal from V.4 may be connected to the second wiring through the through electrode and supplied to the second semiconductor substrate.

According to a fifth aspect of the present invention, in the solid-state imaging device of the third aspect or the fourth aspect, it is formed on at least one of the first semiconductor substrate and the second semiconductor substrate. Controlling the first photoelectric conversion element and the second photoelectric conversion element via the first wiring or the second wiring, and the first photoelectric conversion element and the second photoelectric conversion element A peripheral circuit for outputting the photoelectrically converted electric signal to the first wiring or the second wiring, the peripheral circuit formed on the first semiconductor substrate, and the second semiconductor substrate Among the formed peripheral circuits, at least one peripheral circuit which realizes the same function necessary for control of each of the first photoelectric conversion element and the second photoelectric conversion element is the first one. Photoelectric conversion element and before Even if a common peripheral circuit integrated with a function realized to correspond to both of the second photoelectric conversion element is formed on one of the first semiconductor substrate and the second semiconductor substrate Good.

According to a sixth aspect of the present invention, in the solid-state imaging device of the fifth aspect, the common peripheral circuit is a clock generator that generates the reference clock signal based on the supplied master clock. A storage device as the peripheral circuit that stores setting values for defining the operation of the solid-state imaging device, or an electrical signal obtained by photoelectric conversion of the first photoelectric conversion element and the second photoelectric conversion element The peripheral circuit may be any one of the serializers, which is the peripheral circuit that outputs a serial imaging signal to the outside.

According to a seventh aspect of the present invention, in the solid-state imaging device according to the first aspect, the interval at which the first photoelectric conversion element is formed is incident on the first semiconductor substrate to be the first. It may be equal to or less than the interval at which the light transmitted through the photoelectric conversion layer starts to be affected by diffraction.

According to the eighth aspect of the present invention, the fluorescence observation endoscope apparatus is a fluorescence observation endoscope apparatus for observing a fluorescent substance, and the test object is irradiated with visible light and the fluorescent substance. A light source device capable of irradiating the inspection object with light including a wavelength band of excitation light for emitting fluorescence, and a first photoelectric conversion layer in which a first photoelectric conversion element for photoelectrically converting incident light is formed And a first semiconductor substrate having a first wiring layer on which a first wiring is formed on the surface opposite to the surface on which light is incident to the first photoelectric conversion element; A second photoelectric conversion layer is formed on a surface of the first semiconductor substrate opposite to the light incident side, and a second photoelectric conversion element is formed to photoelectrically convert light transmitted through the first semiconductor substrate. And a second semiconductor substrate on which a second wiring layer in which a second wiring is formed is formed A dielectric multilayer filter disposed between the first semiconductor substrate and the second semiconductor substrate, and the first photoelectric conversion layer formed between the first photoelectric conversion element, A reflective layer formed by being filled with a low refractive index material having a smaller refractive index of light than the first photoelectric conversion layer, and the first wiring layer formed at a position corresponding to the first photoelectric conversion element And a solid-state imaging device having a light transmission region, and the solid-state imaging device is disposed at a distal end portion of an insertion portion inserted into the inside of a living body.

According to a ninth aspect of the present invention, there is provided a method of manufacturing a solid-state imaging device, comprising: a first photoelectric conversion layer in which a first photoelectric conversion element for photoelectrically converting incident light is formed; A light is incident on a first semiconductor substrate having a first wiring layer on which a first wiring is formed on the surface opposite to the surface on which light is incident on the element, and the first semiconductor substrate The second photoelectric conversion layer is formed on the side opposite to the side where the light is transmitted, and the second photoelectric conversion element is formed to photoelectrically convert the light transmitted through the first semiconductor substrate, and the second wiring is formed. Method of manufacturing a solid-state imaging device having a second semiconductor substrate on which a second wiring layer is formed, and in the first photoelectric conversion layer, between the first photoelectric conversion elements After forming a recess with a depth of 1 um or more from the surface of the first photoelectric conversion layer First step of forming the first reflective layer is filled with a low refractive index material having a refractive index less light than photoelectric conversion layer to said recess including,.

According to a tenth aspect of the present invention, in the method for manufacturing a solid-state imaging device according to the ninth aspect, the first photoelectric conversion element in the first wiring layer at least before the first step. Forming a light transmitting region at a position corresponding to the second surface, and forming a back surface electrode for drawing out the first wiring on the surface opposite to the light incident side to the first semiconductor substrate to form a flat surface A third step of forming the first bonding surface, a fourth step of forming a dielectric multilayer filter on the surface on the side where light is incident to the second semiconductor substrate, and the dielectric multilayer film A fifth step of forming a protective film thicker than the thickness of each layer of the dielectric forming the dielectric multilayer filter on the surface on the light incident side of the filter; the protective film and the dielectric multilayer Through the membrane filter and on the side where light is incident on the protective film A sixth step of forming a through electrode for drawing out the second wiring, and a second step in which the formed through electrode and the protective film are planarized together on the surface on the light incident side to the protective film A seventh step of forming a bonding surface, the first bonding surface and the second bonding surface are opposed to and bonded, and the corresponding back surface electrode and the through electrode are connected physically and electrically And the eighth step of

According to each of the above aspects, in the solid-state imaging device configured to stack a plurality of semiconductor substrates on which the photoelectric conversion portions are formed and simultaneously image visible light and fluorescence excited by the fluorescent substance, the image quality of the image obtained by imaging fluorescence It is possible to provide a solid-state imaging device capable of achieving downsizing while suppressing a drop in the size, a fluorescence observation endoscope apparatus using the solid-state imaging device, and a method of manufacturing the solid-state imaging device.

BRIEF DESCRIPTION OF THE DRAWINGS It is the block diagram which showed schematic structure of the fluorescence observation endoscope apparatus in embodiment of this invention. It is the block diagram which showed schematic structure of the fluorescence observation endoscope apparatus of embodiment of this invention. It is the block diagram which showed schematic structure of the solid-state imaging device with which the fluorescence observation endoscope apparatus of embodiment of this invention was equipped. It is the block diagram which showed an example of arrangement | positioning of each component in the solid-state imaging device with which the fluorescence observation endoscope apparatus of embodiment of this invention was equipped. It is sectional drawing which showed an example of the structure of the solid-state imaging device with which the fluorescence observation endoscope apparatus of embodiment of this invention was equipped. It is the figure which showed an example of the distribution characteristic of the intensity | strength of the light in the solid-state imaging device with which the fluorescence observation endoscope apparatus of embodiment of this invention was equipped. It is sectional drawing explaining the outline of the manufacturing method of the solid-state imaging device with which the fluorescence observation endoscope apparatus of embodiment of this invention was equipped. It is sectional drawing explaining the outline of the manufacturing method of the solid-state imaging device with which the fluorescence observation endoscope apparatus of embodiment of this invention was equipped. It is sectional drawing explaining the outline of the manufacturing method of the solid-state imaging device with which the fluorescence observation endoscope apparatus of embodiment of this invention was equipped. It is the figure which showed an example of the structure of the conventional laminated | stacked solid-state imaging device, and the distribution characteristic of the intensity | strength of light.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the case where the solid-state imaging device of the present invention is mounted on the fluorescence observation endoscope device of the present invention will be described. FIG. 1 is a configuration diagram showing a schematic configuration of a fluorescence observation endoscope apparatus according to an embodiment of the present invention.

In FIG. 1, the fluorescence observation endoscope apparatus 1 includes an endoscope scope unit 10, a light source device 20, an external processing unit 30, and a color monitor 40. The fluorescence observation endoscope apparatus 1 is, for example, an endoscope apparatus for laparoscopic surgery. In the fluorescence observation endoscope apparatus 1, the insertion portion into the body in the endoscope unit 10 is inserted into the abdomen 900 of the person to be examined, and the object to be observed 901 such as a living tissue in the body of the person to be examined Take a picture. FIG. 1 shows a state in which the insertion portion of the endoscopic scope unit 10 constituting the fluorescence observation endoscope apparatus 1 is inserted into the abdomen 900 of a person to be inspected to photograph the object to be inspected 901 .

The fluorescence observation endoscope apparatus 1 is used for a test subject in a state in which a derivative-labeled antibody (fluorescent drug) such as ICG is previously administered into the body. In the following description, it is assumed that ICG is administered as a fluorescent drug in the body of the subject.

The fluorescence observation endoscope apparatus 1 excites and fluoresces the ICG administered by the photographing of the test subject 901 with visible light (hereinafter referred to as “normal photographing”) and irradiation of excitation light such as near infrared light And imaging the subject 901 with fluorescence (hereinafter referred to as “fluorescent imaging”).

In the fluorescence observation endoscope apparatus 1, the endoscope unit 10 includes an insertion unit 11 and an operation unit 12. In the fluorescence observation endoscope apparatus 1, the operation unit 12 of the endoscope unit 10 and the light source device 20 are connected by an optical signal cable 50. In the fluorescence observation endoscope apparatus 1, the operation unit 12 of the endoscope unit 10 and the external processing unit 30 are connected by an electric signal cable 60.

In the endoscope 10, the insertion unit 11 is inserted into the abdomen 900 or the like of a person to be examined, and captures an image of the subject 901. At this time, the illumination light guided through the light signal cable 50 is irradiated to the object to be inspected 901 from the tip of the insertion portion 11. The endoscope scope unit 10 outputs an imaging signal corresponding to the imaged image of the test subject 901 to the external processing unit 30 via the electric signal cable 60.

The insertion portion 11 is inserted into the body of the test subject from the abdomen 900 of the test subject in a state in which ICG has been previously administered. In the endoscope scope unit 10, the insertion unit 11 includes an imaging unit 13 at the distal end. The imaging unit 13 generates an imaging signal obtained by converting an image of the inspection object 901 into an electrical signal. Then, the imaging unit 13 outputs the generated imaging signal to the external processing unit 30 via the insertion unit 11, the operation unit 12, and the electric signal cable 60.

The operation unit 12 is a support unit that controls the operation of the insertion unit 11 and the imaging unit 13 by, for example, an operation of an examiner (for example, a doctor who performs laparoscopic surgery). In the endoscope scope unit 10, the operation unit 12 includes an imaging control switch 14 for controlling imaging in the fluorescence observation endoscope apparatus 1. The imaging control switch 14 outputs a control signal for instructing imaging (normal imaging or fluorescent imaging) to the external processing unit 30 via the operation unit 12 and the electric signal cable 60, for example, in accordance with the operation of the examiner. .

The light source device 20 emits illumination light to be applied to the object to be inspected 901 when observing the object to be inspected 901 in the fluorescence observation endoscope apparatus 1. The illumination light emitted from the light source device 20 is guided to the operation unit 12 of the endoscope unit 10 through the light signal cable 50, and the imaging unit 13 provided at the tip of the insertion unit 11 irradiates the inspection object 901 Be done. The light source device 20 emits illumination light in a wavelength band used to image the subject 901 in the fluorescence observation endoscope apparatus 1. More specifically, in the light source device 20, visible light used by the fluorescence observation endoscope apparatus 1 to perform normal imaging of the inspection object 901 and fluorescence of the inspection object 901 by the fluorescence observation endoscope apparatus 1 And emitting excitation light including excitation light used to perform imaging.

The external processing unit 30 performs predetermined image processing on an imaging signal of the subject 901 to be inspected, which is input through the electrical signal cable 60 and captured by the imaging unit 13 included in the endoscope unit 10, This is an image processing apparatus that generates an image including the photographed subject 901. The external processing unit 30 outputs the image signal of the image including the generated inspection object 901 to the color monitor 40 for display. In addition, the external processing unit 30 transmits a control signal (drive signal) when the imaging unit 13 captures an image of the test object 901 to the imaging unit 13 via the electric signal cable 60.

The color monitor 40 is a display device such as, for example, a liquid crystal display (LCD) that displays an image including the test subject 901 according to the image signal input from the external processing unit 30.

With such a configuration, the fluorescence observation endoscope apparatus 1 performs normal imaging of the subject 901 with visible light and fluorescence imaging of the subject 901 with fluorescence in which the ICG administered to the subject is excited by excitation light. And do. Then, the fluorescence observation endoscope apparatus 1 presents, to the examiner, an image including the photographed subject 901 to be examined.

Next, a more detailed configuration of the fluorescence observation endoscope apparatus 1 will be described. FIG. 2 is a block diagram showing a schematic configuration of the fluorescence observation endoscope apparatus 1 according to the embodiment of the present invention. In FIG. 2, the imaging unit 13 provided at the tip of the endoscope scope unit 10 constituting the fluorescence observation endoscope apparatus 1 includes an imaging lens 130, an excitation light cut filter 131, and a laminated image sensor 132. And a light guide 51.

The light guide 51 is, for example, a light guide cable such as an optical fiber that guides the illumination light emitted by the light source device 20 to the imaging unit 13. The illumination light emitted by the light source device 20 is guided by the light guide 51 to the imaging unit 13 through the light signal cable 50, the operation unit 12, and the insertion unit 11, and the tip of the light guide 51 irradiates the inspection object 901 Be done.

The imaging lens 130 emits the incident light, that is, the reflected light and fluorescence from the inspection object 901 irradiated with the illumination light emitted by the light source device 20 to the laminated image sensor 132 side, and Are formed on the imaging surface of the laminated image sensor 132.

The excitation light cut filter 131 is an optical filter that reflects or absorbs only the light of the wavelength band of the excitation light contained in the reflected light from the inspection object 901 emitted from the imaging lens 130 and the fluorescence and attenuating the light. For example, the excitation light cut filter 131 attenuates light in a wavelength band around 700 nm to 800 nm, which is the wavelength band of excitation light. In the following description, since the excitation light cut filter 131 attenuates the excitation light contained in the incident reflected light and the fluorescence to a level close to “0”, it is not “attenuation” but “cut (cut)”. It demonstrates using the expression "." The excitation light cut filter 131 emits the reflected light and fluorescence from the test object 901 whose excitation light has been cut to the stacked image sensor 132.

The stacked image sensor 132 exposes (detects) incident light according to control from the control unit 31 described later provided in the external processing unit 30, and outputs an electric signal obtained by photoelectric conversion of the exposed light as an imaging signal. It is a solid-state imaging device of the present invention. The laminated image sensor 132 exposes the reflected light and fluorescence from the object to be inspected 901 from which the excitation light emitted from the excitation light cut filter 131 is cut, and the imaging signals corresponding to the exposed reflected light and fluorescence are Generate The stacked image sensor 132 is an image sensor that exposes (detects) reflected light (hereinafter referred to as a “visible image pickup image sensor”) and an image sensor that exposes (detects) fluorescence transmitted through the visible image pickup image sensor (Hereinafter, referred to as “fluorescent image capturing image sensor”), and an interlayer filter disposed between the visible image capturing image sensor and the fluorescent image capturing image sensor. That is, the stacked image sensor 132 has a structure in which the visible image capturing image sensor substrate and the fluorescent image capturing image sensor substrate are stacked with an interlayer filter interposed therebetween.

The visible image pickup image sensor constituting the stacked image sensor 132 outputs an image pickup signal obtained by exposing light (visible light) in the visible region of the reflected light. In a visible image pickup image sensor, a plurality of pixels provided with photoelectric conversion elements (light receiving elements) such as photodiodes for photoelectrically converting incident light are arranged in a matrix. A pixel (hereinafter referred to as “R pixel”) attached with an on-chip color filter that transmits light (visible light) in the red (R) wavelength band is attached to the pixels arranged in the visible image pickup image sensor , Pixels (hereinafter referred to as "G pixels") attached with an on-chip color filter that transmits light (visible light) in the green (G) wavelength band and light (visible light) in the blue (B) wavelength band There is a pixel (hereinafter referred to as a "B pixel") to which an on-chip color filter that transmits light is attached.

In addition, the interlayer filter constituting the layered image sensor 132 transmits a visible image pickup image sensor (more specifically, a region of R pixel, G pixel, and B pixel arranged in the visible image pickup image sensor) Among the lights, it is an optical filter that reflects or absorbs light in the visible region (visible light) to attenuate it. In the multilayer image sensor 132, for example, a multilayer interference filter in which inorganic materials are stacked in multiple layers, such as a dielectric multilayer filter or a Fabry-Perot filter, is used as an interlayer filter. In the dielectric multilayer filter and the Fabry-Perot filter, it is considered that it is easier for the dielectric multilayer filter to realize an interlayer filter having a characteristic of attenuating light in a wide wavelength band. In the following description, the interlayer filter is described as a dielectric multilayer filter.

Further, the fluorescent image pickup image sensor constituting the laminated type image sensor 132 outputs a fluorescent light, that is, an image pickup signal obtained by exposing light in the infrared region (near infrared light). The fluorescence image pickup image sensor includes light transmitted through a visible image pickup image sensor (more specifically, an R pixel area, a G pixel area, and a B pixel area disposed in the visible image pickup image sensor) and an interlayer filter. A plurality of pixels provided with photoelectric conversion elements (light receiving elements) such as photodiodes for photoelectric conversion are arranged in a matrix. In the following description, the pixels disposed in the fluorescence image capturing image sensor are referred to as “fluorescent pixels”. The fluorescent pixel is a pixel that exposes (detects) fluorescence emitted from the ICG excited and excited by the excitation light such as near-infrared light emitted by the light source device 20 to the subject.

A detailed description of the structure of the laminated image sensor 132, the arrangement and configuration of each pixel in the visible image capturing image sensor substrate and the fluorescent image capturing image sensor substrate, and the configuration of the interlayer filter will be described later.

The stacked image sensor 132 is an imaging signal (hereinafter referred to as “visible image pickup”) according to an electric signal (hereinafter referred to as “pixel signal”) obtained by exposing and photoelectrically converting each pixel disposed in the visible image pickup image sensor A signal “)” is output to the external processing unit 30 by the imaging signal line 61 passing through the insertion unit 11, the operation unit 12, and the electric signal cable 60. In addition, the multi-layered image sensor 132 can visualize an imaging signal (hereinafter referred to as “fluorescent image imaging signal”) corresponding to a pixel signal obtained by exposing and photoelectrically converting each pixel disposed in the fluorescent image imaging image sensor. Similar to the image pickup signal, the image pickup signal line 61 passing through the insertion unit 11, the operation unit 12, and the electric signal cable 60 is output to the external processing unit 30. In the following description, when the visible image pickup signal and the fluorescence image pickup signal are not distinguished from one another, they are simply referred to as “imaging signals”.

The layered image sensor 132 performs analog / digital conversion (A / D conversion) on analog pixel signals output from respective pixels arranged in the visible image capturing image sensor and the fluorescent image capturing image sensor. A digital value representing the magnitude of the pixel signal, so-called RAW data, is output to the external processing unit 30 as each imaging signal. The RAW data is a parallel digital value representing the magnitude of each pixel signal.

In order to reduce the number of signal lines of the imaging signal line 61 for transmitting each RAW data as an imaging signal to the external processing unit 30, the layered image sensor 132 is a parallel digital value RAW data (hereinafter referred to as “ After parallel / serial conversion of parallel RAW data into serial digital value RAW data (hereinafter referred to as “serial RAW data”), each serial RAW data is output as an imaging signal to the external processing unit 30.

Further, in FIG. 2, the light source device 20 constituting the fluorescence observation endoscope apparatus 1 includes the setting unit 21, two white light sources 221 and two white light sources 222, two die clock mirrors 231 and a die clock mirror 232. And a light irradiation lens 24.

Each of the white light source 221 and the white light source 222 is a light source that emits white light. However, the white light source 221 emits white light of an intensity corresponding to the control from the setting unit 21. As the white light source 221 and the white light source 222, for example, a xenon lamp is used. However, as the white light source 221 and the white light source 222, for example, a halogen lamp or a white LED (Light Emitting Diode) light source may be used. In the following description, when the white light source 221 and the white light source 222 are not distinguished from one another, they are referred to as “white light source 220”.

The dichroic mirror 231 and the dichroic mirror 232 correspond to the white light source 221 and the white light source 222, respectively, and select (split) light of a specific wavelength band from the white light emitted by the corresponding white light source 220. Do. Each of the die clock mirror 231 and the die clock mirror 232 emits the separated light to the light irradiation lens 24.

More specifically, in the dichroic mirror 231, the light irradiation lens 24 is disposed for light in the wavelength band of visible light (for example, light in the wavelength band of 400 nm to 700 nm) of the white light emitted by the corresponding white light source 221 The visible light (white light) separated by being reflected in the vertical direction is emitted to the light irradiation lens 24. Here, visible light emitted from the dichroic mirror 231 to the light irradiation lens 24 includes light in the blue (B) wavelength band (for example, light in the 400 nm to 500 nm wavelength band) and green (G) wavelength bands. Light (for example, light in a wavelength band of 500 nm to 600 nm) and light in a red (R) wavelength band (for example, light in a wavelength band of 600 nm to 700 nm) are included. In addition, the dichroic mirror 232 reflects light in the wavelength band of excitation light (for example, light in the wavelength band of 700 nm to 800 nm) of the white light emitted by the corresponding white light source 222 in the direction in which the light irradiation lens 24 is disposed. The excitation light (near infrared light) for exciting the ICG separated by the irradiation is emitted to the light irradiation lens 24.

The light irradiation lens 24 is an optical lens which condenses the light of the specific wavelength band emitted from each of the die clock mirror 231 and the die clock mirror 232 to the same degree as the diameter of the light guide 51. The light irradiation lens 24 emits the condensed light to the first end face of the light guide 51. Thereby, the light guide 51 guides the light emitted from the light irradiation lens 24 to the imaging unit 13 and emits the light from the second end face disposed at the tip of the imaging unit 13 as illumination light emitted by the light source device 20 The test object 901 is irradiated.

The setting unit 21 causes the white light source 221 to emit light based on the visible image pickup signal input from the external processing unit 30 and the digital value (parallel RAW data) representing the magnitude of each pixel signal included in the fluorescence image pickup signal. Control the intensity of the white light.

Further, in FIG. 2, the external processing unit 30 constituting the fluorescence observation endoscope apparatus 1 includes a control unit 31, a deserializer 32, an image processing unit 33, and a digital / analog conversion unit (D / A conversion unit) 34. And is comprised.

The deserializer 32 is an original parallel signal obtained by analog-to-digital conversion of the stacked image sensor 132 from an imaging signal (serial RAW data) output from the stacked image sensor 132 included in the imaging unit 13 and transmitted through the imaging signal line 61. Restore RAW data. That is, the deserializer 32 performs serial / parallel conversion on the input serial RAW data to restore parallel RAW data. Then, the deserializer 32 outputs the restored parallel RAW data to the image processing unit 33.

The image processing unit 33 performs various types of image processing on each parallel RAW data output from the deserializer 32 under the control of the control unit 31, and the test object 901 captured by the layered image sensor 132. Generate an image of digital values including More specifically, under the control of the control unit 31, the image processing unit 33 selects one of red (R), green (G), and blue (B) based on parallel RAW data of the visible image pickup signal. Generate a visible image of the digital value of visible light. Further, the image processing unit 33 generates a fluorescence image of a digital value of fluorescence based on parallel RAW data of the fluorescence image imaging signal according to the control from the control unit 31. Under the control of the control unit 31, the image processing unit 33 generates image data for display (hereinafter referred to as "image data for display") of the data of the visible image and the data of the fluorescence image including the inspection object 901 generated Output to the digital / analog converter 34.

Further, the image processing unit 33 sets the intensity of the white light in parallel RAW data (parallel RAW data of the visible image pickup signal and the fluorescence image pickup signal) output from the deserializer 32 according to the control from the control unit 31. It outputs to the setting part 21 with which the light source device 20 was equipped as a monitoring signal for this. For example, the image processing unit 33 may be a digital value representing the magnitude of the pixel signal output from each pixel disposed in the visible image capturing image sensor and the fluorescent image capturing image sensor provided in the stacked image sensor 132. , And output to the setting unit 21 as a monitoring signal.

The image processing performed by the image processing unit 33 on parallel RAW data includes, for example, demosaicing processing, white balance processing, gamma correction processing, and the like. In the demosaicing process, based on the input parallel RAW data (reconstructed parallel RAW data), an image in which all pixels included in the image are represented by pixel signals (digital values) corresponding to the light of the same wavelength band This is image processing similar to so-called three-plate processing that generates data. In the white balance processing, the digital value of each pixel is set so that the magnitude of the digital value of the pixel signal corresponding to each pixel at the same position in the image data becomes the same value for the white (white) subject. Image processing to adjust the level by multiplying the gain value by. In gamma correction processing, when an image corresponding to image data subjected to white balance processing is output and displayed on the color monitor 40, the color of the image signal of the image to be output and the image actually displayed on the color monitor 40. Image processing to correct non-linearity of taste. The image processing performed by the image processing unit 33 on parallel RAW data is controlled by the control unit 31.

The digital / analog conversion unit 34 performs digital / analog conversion (D / A conversion) on each of the display image data (digital value) input from the image processing unit 33. The digital / analog conversion unit 34 outputs the image signal (analog signal) subjected to digital / analog conversion to the color monitor 40 as an image signal for display generated by the external processing unit 30, and the color monitor 40 Display the image that contains.

The control unit 31 is a processing device such as a central processing unit (CPU), for example, and controls the operation of the layered image sensor 132 provided in the imaging unit 13. More specifically, the control unit 31 performs various settings or the like when the laminated image sensor 132 captures an image of the test object 901 in the normal photographing and the fluorescent photographing of the test object 901 by the fluorescence observation endoscope apparatus 1. The timing at which the subject 901 is imaged is controlled. For example, the control unit 31 sets parameters such as a time (exposure time) and an interval (so-called frame rate) for exposing light incident on the laminated image sensor 132, and exposes the laminated image sensor 132 with the set parameters. The operation of (imaging) is performed. Further, for example, the control unit 31 sets an analog / digital conversion or parallel / serial conversion parameter to be performed when the laminated image sensor 132 outputs an imaging signal, and an imaging signal (serial RAW data) converted by the set parameter ) Is output to the stacked image sensor 132.

Further, the control unit 31 controls a method of image processing performed by the image processing unit 33. More specifically, the control unit 31 generates parallel RAW data when the image processing unit 33 generates image data such as a visible image or a fluorescent image including the inspection object 901 captured by the laminated image sensor 132. Control the type and order of image processing to be performed. For example, the control unit 31 causes the image processing unit 33 to generate image data subjected to the gamma correction processing as display image data, and causes the digital / analog conversion unit 34 to output the image data. Further, for example, the control unit 31 causes the image processing unit 33 to perform image processing on the image data of the fluorescence image subjected to the gamma correction processing, and the image data subjected to the superposition processing for superimposing the image data of the visible image subjected to the gamma correction processing. It is generated as display image data and output to the digital / analog converter 34. Further, for example, the control unit 31 causes the image processing unit 33 to generate the image data of the visible image and the fluorescence image subjected to the demosaicing process as a monitoring signal for setting the intensity of the white light, and causes the light source device 20 to It is output to the provided setting unit 21.

With such a configuration, the fluorescence observation endoscope apparatus 1 captures an image including the object to be inspected 901 by normal imaging with visible light and fluorescence imaging with fluorescence. And the fluorescence observation endoscope apparatus 1 displays each image including the to-be-tested object 901 which image | photographed to the color monitor 40, and shows it to a test operator.

Next, a laminated image sensor 132 which is a solid-state imaging device of the present invention mounted on the fluorescence observation endoscope apparatus 1 will be described. First, the configuration of the stacked image sensor 132 will be described. FIG. 3 is a block diagram showing a schematic configuration of a solid-state imaging device (stacked image sensor 132) provided in the fluorescence observation endoscope apparatus 1 of the embodiment of the present invention. In the stacked image sensor 132, two image sensors (solid-state imaging device) of a visible image capturing image sensor and a fluorescent image capturing image sensor are stacked. In the stacked image sensor 132, each image sensor is provided with the same components.

However, the components for realizing the functions of the image sensor also include components that can be made common to the respective image sensors. For example, components that can be made common by integrating components realized by the respective components into one component or components that realize the same function as one component are also included. ing. For this reason, in the multilayer image sensor 132, each of the visible image capturing image sensor and the fluorescent image capturing image sensor is not configured to include all components for realizing the function of the image sensor. That is, in the layered image sensor 132, only one of the components that can be made common to each of the visible image capturing image sensor and the fluorescent image capturing image sensor is provided in any of the image sensors. That is, in the layered image sensor 132, components common to each of the visible image capturing image sensor and the fluorescent image capturing image sensor are dispersedly provided.

In the following description, in order to facilitate the description, all the components for realizing the function of the image sensor are distinguished without distinguishing the common components provided separately in the respective image sensors. It is described as being provided for one image sensor. In addition, the description regarding the arrangement | positioning to each image sensor board | substrate of the component which can be made common in each image sensor, and each made common component is mentioned later. In the following description, it is representatively described that the visible image capturing image sensor stacked on the stacked image sensor 132 includes all the components for realizing the function of the image sensor.

In FIG. 3, the visible image pickup image sensor includes a pixel unit 1321, a reading unit 1322, an analog / digital converter 1323, a control circuit 1324, a serial access memory 1325, and a serializer 1326.

In the pixel portion 1321, a plurality of pixels 1320 are arranged. FIG. 3 illustrates an example of a pixel portion 1321 in which a plurality of pixels 1320 are two-dimensionally arranged in 7 rows and 8 columns. Each pixel 1320 disposed in the pixel portion 1321 generates a signal charge of an amount corresponding to the intensity of light incident on each disposed position, and accumulates the generated signal charge.

Note that, as described above, the plurality of pixels 1320 arranged in the pixel portion 1321 in the visible image pickup image sensor include R pixels, G pixels, and B pixels. In addition, in the image sensor for capturing a fluorescent image, all the pixels 1320 arranged in the pixel portion 1321 are fluorescent pixels.

The arrangement of the pixels 1320 in the visible image pickup image sensor substrate and the fluorescent image pickup image sensor substrate is not limited to the same arrangement. That is, the total number of R pixels, G pixels, and B pixels in the visible image pickup image sensor and the number of fluorescent pixels in the fluorescent image pickup image sensor are not limited to the same number of pixels. . For example, the number of pixels of the fluorescence image pickup image sensor may be smaller than that of the visible image pickup image sensor. In this case, for example, the area of one pixel 1320 (fluorescent pixel) disposed on the fluorescence image pickup image sensor substrate is equivalent to four (2 rows and 2 columns) of pixels 1320 disposed on the visible image pickup image sensor substrate. It may be an area of 4). Thus, the opening area for receiving light in the fluorescent pixels arranged on the fluorescent image pickup image sensor substrate is the opening of any of the R pixel, G pixel or B pixel arranged on the visible image pickup image sensor substrate The fluorescent pixel placed on the image sensor substrate for capturing a fluorescent image, which is four times the area, can receive more light.

The readout unit 1322 is a peripheral circuit that controls readout of signal charges generated and accumulated by the pixels 1320 disposed in the pixel unit 1321. The reading unit 1322 includes, for example, a vertical scanning circuit 13221, a horizontal scanning circuit 13222, and the like. The vertical scanning circuit 13221 drives each pixel 1320 in the pixel portion 1321 row by row under control of the control circuit 1324 and generates a pixel signal as a voltage signal corresponding to the signal charge stored in each pixel 1320. It is a peripheral circuit to be output to the vertical signal line 1327 as Thus, pixel signals (analog signals) output from the respective pixels 1320 for each row are input to the analog / digital conversion unit 1323. The horizontal scanning circuit 13222 controls the analog / digital conversion unit 1323 for each column of the pixels 1320 in the pixel unit 1321 according to the control from the control circuit 1324, and the analog / digital conversion unit 1323 performs analog / digital conversion. It is a peripheral circuit that causes the horizontal signal line 1328 to sequentially output the pixel signal (digital value) after being processed for each column of the pixels 1320 in the pixel portion 1321. Accordingly, pixel signals of digital values representing the magnitudes of analog pixel signals output from the respective pixels 1320 analog-to-digital converted by the analog / digital conversion unit 1323 are included in the respective pixels 1320 disposed in the pixel unit 1321. Each column is sequentially input to the serializer 1326.

The analog / digital conversion unit 1323 is a peripheral circuit that performs analog / digital conversion of analog pixel signals output from the respective pixels 1320 in the pixel unit 1321 under the control of the vertical scanning circuit 13221 in the reading unit 1322. . In FIG. 3, an analog / digital conversion circuit (A / D conversion circuit) 13230 that outputs a digital value obtained by analog / digital converting a voltage value of an input analog signal is arranged in each pixel portion 1321. 16 shows an example of the analog / digital converter 1323 having a configuration provided for each column of. Each of the analog / digital conversion circuits 13230 outputs a pixel signal of a digital value obtained by analog / digital converting the voltage value of the analog pixel signal input from the pixel 1320 of the corresponding column under the control of the control circuit 1324 Peripheral circuits. The analog / digital conversion unit 1323 receives the horizontal signal line 1328 of the pixel signal of the digital value obtained by analog / digital conversion of each of the analog / digital conversion circuits 13230 according to the control from the horizontal scanning circuit 13222 in the reading unit 1322. It outputs to the serializer 1326 via

Note that, in FIG. 3, the analog / digital conversion unit 1323 having a configuration including the analog / digital conversion circuit 13230 in each column of the pixels 1320 in the pixel portion 1321, that is, one analog / digital conversion circuit 13230 in one column. Indicated. However, the configuration in the analog / digital converter 1323 is not limited to the configuration shown in FIG. For example, the analog / digital conversion unit 1323 may be configured to include one analog / digital conversion circuit 13230 for a plurality of columns of the pixels 1320 in the pixel unit 1321. Further, one analog / digital conversion circuit 13230 may be configured to sequentially perform analog / digital conversion on voltage values of analog pixel signals output from the pixels 1320 of the respective columns.

The serializer 1326 is a peripheral circuit that performs parallel / serial conversion of pixel signals (digital values) sequentially input from the analog / digital converter 1323, that is, parallel RAW data, in accordance with control from the control circuit 1324. The serializer 1326 outputs the parallel / serial converted serial RAW data as an imaging signal (visible image imaging signal) to the outside of the visible image capturing image sensor. At this time, the serializer 1326 outputs the serial RAW data to the outside of the visible image pickup image sensor as a visible image pickup signal in accordance with, for example, a low voltage differential signaling (LVDS) method which is a differential interface method. In this case, the serializer 1326 also performs LVDS type termination processing and the like.

The control circuit 1324 is a peripheral circuit that controls the respective components included in the visible image capturing image sensor, that is, the entire visible image capturing image sensor. The control circuit 1324 controls the operation of each component included in the visible image pickup image sensor based on the setting (parameter) regarding the operation of the visible image pickup image sensor stored in the serial access memory 1325. For example, the control circuit 1324 reads the reading unit 1322 (vertical scanning circuit 13221 and horizontal scanning circuit 13222) based on parameters related to the operation of exposure (imaging) of the visible image pickup image sensor stored in the serial access memory 1325. A control signal for controlling each of the analog / digital converter 1323 and the serializer 1326 is generated, and the generated control signal is output to each component. As a result, each component provided in the visible image capturing image sensor performs each of the operations described above to output to the outside serial RAW data obtained by exposing (detecting) light incident on the visible image capturing image sensor. Do.

The serial access memory 1325 is a storage device storing various setting values (parameters) for defining the operation of the visible image capturing image sensor, that is, a peripheral circuit serving as a so-called register. The serial access memory 1325 is, for example, a SPI (Serial Peripheral Interface) memory. The serial access memory 1325 stores parameters necessary for the visible image capturing image sensor to perform an operation of exposure (imaging) in accordance with the control from the control unit 31 provided in the external processing unit 30. For example, the serial access memory 1325 may be an exposure time (accumulation time) or a frame rate at which the visible image pickup image sensor performs an operation of exposure (pickup), an image size representing the size of an image to be exposed (pickup), It stores parameters such as a reading method when outputting a signal. The serial access memory 1325 is not limited to the SPI type memory, and may be, for example, an I2C (Inter-Integrated Circuit) type memory.

In the stacked image sensor 132, the visible image capturing image sensor and the fluorescent image capturing image sensor having such a configuration are stacked. However, as described above, only one component (peripheral circuit) common to the two image sensors is disposed on any of the image sensor substrates (dispersed on each of the image sensor substrates). Here, the arrangement of the respective components (peripheral circuits) in the visible image capturing image sensor substrate and the fluorescent image capturing image sensor substrate constituting the stacked image sensor 132 will be described.

FIG. 4 is a block diagram showing an example of the arrangement of respective components in a solid-state imaging device (stacked image sensor 132) provided in the fluorescence observation endoscope apparatus 1 of the embodiment of the present invention. In FIG. 4, components (peripheral circuits disposed on the image sensor substrate of the visible image capturing image sensor substrate 132-1 constituting the stacked image sensor 132 and the fluorescence image capturing image sensor substrate 132-2 are provided. And schematically show examples of signal line connections between respective image sensor substrates. FIG. 4 also shows an example of the arrangement of terminals through which the laminated image sensor 132 inputs and outputs signals to and from the outside.

Note that, in FIG. 4, in addition to the terminal of the signal line with which the stacked image sensor 132 exchanges with the outside, the terminals of two power supplies for operating the stacked image sensor 132 (power supply VDD1 and ground GND1 And the power supply VDD2 and the ground GND2). In the stacked image sensor 132, electrode pads (input / output pads) serving as the respective terminals are disposed only on the visible image pickup image sensor substrate 132-1. For example, in the stacked image sensor 132, each electrode pad (input / output pad) is disposed along the outer periphery of the visible image capturing image sensor substrate 132-1.

In the stacked image sensor 132, the pixel unit 1321, the reading unit 1322, and the analog / digital converting unit 1323 are independent in each of the visible image capturing image sensor substrate 132-1 and the fluorescent image capturing image sensor substrate 132-2. Are arranged as separate components (peripheral circuits). In FIG. 4, the pixel unit 1321-1, which is a combination of the pixel unit 1321 and the analog / digital conversion unit 1323, is disposed on the visible image pickup image sensor substrate 132-1, and the vertical scanning included in the readout unit 1322 A state in which the circuit 13221 and the horizontal scanning circuit 13222 are arranged as the vertical scanning circuit 13221-1 and the horizontal scanning circuit 13222-1 is shown. Further, in FIG. 4, a pixel unit 1321-2, which is a combination of the pixel unit 1321 and the analog / digital conversion unit 1323, is disposed on the fluorescence image pickup image sensor substrate 132-2 and included in the readout unit 1322. A state in which the vertical scanning circuit 13221 and the horizontal scanning circuit 13222 are respectively arranged as the vertical scanning circuit 13221-2 and the horizontal scanning circuit 1322-2 is shown.

In the multilayer image sensor 132, the control circuit 1324, the serial access memory 1325, and the serializer 1326 are used as components (peripheral circuits, common peripheral circuits) common to the respective image sensors, and an image sensor substrate for picking up a visible image It is disposed on either 132-1 or the image sensor substrate 132-2 for capturing a fluorescent image. FIG. 4 shows a state in which the control circuit 1324 and the serializer 1326 are disposed on the visible image capturing image sensor substrate 132-1, and the serial access memory 1325 is disposed on the fluorescent image capturing image sensor substrate 132-2. ing. In the component (common peripheral circuit) provided commonly to each image sensor in the stacked image sensor 132 (common peripheral circuit), necessary signals are received by the visible image capturing image sensor substrate 132-1 and the fluorescent image capturing image sensor It exchanges with the substrate 132-2. That is, the signal lines of the components (common peripheral circuits) common to the respective image sensors are connected between the visible image capturing image sensor substrate 132-1 and the fluorescent image capturing image sensor substrate 132-2. .

FIG. 4 shows the case where the serial access memory 1325 disposed on the fluorescence image pickup image sensor substrate 132-2 is a SPI type memory (SPI memory). The serial access memory 1325 configures the stacked image sensor 132 based on the controller clock SCK input from the outside of the stacked image sensor 132, the SPI trigger signal CS, the SPI input signal MOSI, and the SPI output signal MISO. It stores various setting values (parameters) and the like for defining the operation of the image sensor. At this time, the serial access memory 1325 divides and stores the storage area of the parameter corresponding to the visible image capturing image sensor constituting the stacked image sensor 132 and the parameter corresponding to the fluorescent image capturing image sensor. In addition, the serial access memory 1325 outputs stored parameters and the like based on the externally input controller clock SCK, SPI trigger signal CS, SPI input signal MOSI, and SPI output signal MISO (for confirmation (for confirmation) Including the output).

The operation of the serial access memory 1325 (SPI memory) corresponding to each signal of the controller clock SCK, the SPI trigger signal CS, the SPI input signal MOSI, and the SPI output signal MISO is the same as that of the existing SPI type memory . Therefore, detailed description of the operation of the serial access memory 1325 is omitted.

As described above, in the configuration of the laminated image sensor 132 shown in FIG. 4, terminals (electrode pads) for inputting and outputting signals are disposed only on the visible image capturing image sensor substrate 132-1. Therefore, the controller clock SCK, the SPI trigger signal CS, the SPI input signal MOSI, and the SPI output signal MISO input to the serial access memory 1325 are sent to the image sensor substrate 132-1 for capturing a visible image. The signal is input from the outside to the arranged terminal (electrode pad), passes through the inside of the visible image pickup image sensor substrate 132-1, and is input to the serial access memory 1325 arranged on the fluorescent image pickup image sensor substrate 132-2. Ru.

The above-described two power supplies (power supply VDD1 and ground GND1, power supply VDD2 and ground GND2) are also included in the visible image pickup image sensor substrate 132-1 in the same manner as the respective signals input to the serial access memory 1325. , And is supplied to the fluorescence image pickup image sensor substrate 132-2. That is, in the stacked image sensor 132, the terminals of the two power supplies supplied to the fluorescent image capturing image sensor substrate 132-2 are shared with the visible image capturing image sensor substrate 132-1.

Further, FIG. 4 shows each of a clock generator 13241 and a timing generator 13242 which are components of the control circuit 1324 disposed on the visible image pickup image sensor substrate 132-1. The clock generator 13241 is a component (peripheral circuit) in the multilayer image sensor 132 based on the master clock MCLK input from the outside to a terminal (electrode pad) disposed on the visible image pickup image sensor substrate 132-1. Is a peripheral circuit that generates a reference clock signal to operate. The clock generator 13241 is configured of, for example, a PLL (Phase Locked Loop). The clock generator 13241 outputs (supplies) the generated reference clock signal to components (peripheral circuits) in the stacked image sensor 132.

The timing generator 13242 is a control signal synchronized with a reference clock signal for controlling the operation of each component (peripheral circuit) included in the stacked image sensor 132 based on the parameters stored in the serial access memory 1325. Are generated and output to corresponding components (peripheral circuits). More specifically, the timing generator 13242 generates the control signal in the vertical scanning circuit 13221-1, the horizontal scanning circuit 13222-1, and the pixel unit 1321-1 disposed on the visible image capturing image sensor substrate 132-1. The signal is output to each of an analog / digital conversion unit 1323 and a serializer 1326 (not shown). Further, the timing generator 13242 can generate the generated control signal in the vertical scanning circuit 13221-2, the horizontal scanning circuit 13222-2, and the pixel portion 1321-2 disposed on the fluorescence image capturing image sensor substrate 132-2. The signal is output to each of the illustrated analog / digital converter 1323.

In the stacked image sensor 132 shown in FIG. 4, the serializer 1326 is not shown in the analog / digital conversion unit 1323 in the pixel unit 1321-1 disposed on the visible image capturing image sensor substrate 132-1, or a fluorescent image Pixel signals (parallel RAW data) sequentially input from an analog / digital conversion unit 1323 (not shown) in the pixel unit 1321-2 disposed on the image sensor substrate 132-2 for imaging are subjected to parallel / serial conversion. The serializer 1326 outputs parallel / serial converted serial RAW data from terminals (electrode pads) of differential signals (differential positive signal pos and differential negative signal neg) for outputting to the outside.

As described above, in the stacked image sensor 132, only one component (peripheral circuit, common peripheral circuit) common to two image sensors is provided to any of the image sensors (dispersed to each image sensor) ). Thus, in the stacked image sensor 132, the number of components (peripheral circuits) arranged in each image sensor can be reduced, and the area (chip area) of the image sensor substrate can be reduced. Further, in the stacked image sensor 132, electrode pads (input / output pads) for inputting / outputting signals to / from the outside are disposed only on the visible image pickup image sensor substrate 132-1, and Common electrode pads (input and output pads) to be terminals. Accordingly, in the stacked image sensor 132, the number of electrode pads (input / output pads) serving as terminals can be reduced, and the chip area can be further reduced.

A component (peripheral circuit, common peripheral circuit) common to the respective image sensors in the stacked image sensor 132 may be transferred to the visible image capturing image sensor substrate 132-1 and the fluorescent image capturing image sensor substrate 132-2. The arrangement is not limited to the arrangement as shown in FIG. 4 but various arrangements are conceivable. For example, in the multi-layer image sensor 132, a clock generator 13241 constituting a control circuit 1324 which is a common component (common peripheral circuit) in each image sensor is disposed on the image sensor substrate 132-2 for capturing a fluorescent light image. The generator 13242 may be disposed on the visible image capturing image sensor substrate 132-1. In this case, the master clock MCLK for the clock generator 13241 to generate the reference clock signal is also the image sensor substrate for capturing a visible image, similarly to the two power supplies described above and the respective signals input to the serial access memory 1325. The signal passes through the inside of 132-1, and is input to the timing generator 13242 disposed on the fluorescence image pickup image sensor substrate 132-2. That is, the terminal (electrode pad) of the master clock MCLK is also shared by the visible image capturing image sensor substrate 132-1 and the fluorescent image capturing image sensor substrate 132-2.

Next, the structure of the stacked image sensor 132 will be described. FIG. 5 is a cross-sectional view showing an example of the structure of a solid-state imaging device (stacked image sensor 132) provided in the fluorescence observation endoscope apparatus 1 according to the embodiment of the present invention. FIG. 5 schematically shows the entire vertical structure of the stacked image sensor 132.

As described above, the stacked image sensor 132 has a structure in which the visible image capturing image sensor substrate 132-1 and the fluorescent image capturing image sensor substrate 132-2 are stacked with an interlayer filter interposed therebetween. More specifically, in the pixel region, the stacked image sensor 132 is a visible image pickup image sensor substrate 132-1, a protective film 132-4, and a dielectric in the direction from the light incident side to the light traveling direction. The multilayer film filter layer 132-3, the fluorescence image pickup image sensor substrate 132-2, and the support substrate 132-5 are stacked in this order.

The visible image capturing image sensor substrate 132-1 is a circuit element for realizing the function of a visible image capturing image sensor that outputs an imaging signal mainly exposed to the reflected light (visible light), and the stacked image sensor 132. The semiconductor substrate forms the respective terminals (electrode pads) in the above.

The dielectric multi-layered film filter layer 132-3 attenuates visible light which passes through the visible image pickup image sensor substrate 132-1 and enters each pixel 1320 disposed on the fluorescent image pickup image sensor substrate 132-2. Layer, which is an optical filter in which inorganic materials such as dielectrics are laminated in multiple layers to form a dielectric multilayer filter. The dielectric multilayer film filter is formed as an interlayer filter disposed between the visible image capturing image sensor substrate 132-1 and the fluorescent image capturing image sensor substrate 132-2. The dielectric multilayer filter is formed, for example, by alternately laminating thin film layers made of silicon dioxide (SiO ₂ ) and thin film layers made of titanium oxide (TiO ₂ ). In the vertical structure of the stacked image sensor 132 shown in FIG. 5, the dielectric multilayer filter layer 132-3 alternately comprises a silicon dioxide (SiO ₂ ) thin film layer 132031 and a titanium oxide (TiO ₂ ) thin film layer 132032. The state which laminated | stacked layer by layer and formed the dielectric multilayer filter 13203 is shown typically.

The protective film 132-4 is a dielectric multilayer filter layer 132-3 in which the visible image capturing image sensor substrate 132-1 and the fluorescent image capturing image sensor substrate 132-2 are stacked in the stacked image sensor 132. It is a layer which forms a protective film to protect. The protective film 132-4 is formed of, for example, a low refractive index material such as silicon dioxide (SiO ₂ ). In the vertical structure of the stacked image sensor 132 shown in FIG. 5, the protective film 132-4 protects the dielectric multilayer filter layer 132-3 at the bonding surface JS.

The fluorescent image pickup image sensor substrate 132-2 is a circuit for realizing the function of a fluorescent image pickup image sensor that outputs an image pickup signal mainly exposed to the fluorescence transmitted through the visible image pickup image sensor substrate 132-1. It is a semiconductor substrate which forms an element.

The support substrate 132-5 is a visible image pickup image sensor substrate 132-1 (including a microlens layer 132-7 to be described later, an on-chip color filter layer 132-6, terminals (electrode pads), etc.), and a protective film 132. This is a semiconductor substrate for strongly supporting the whole of the multilayer image sensor 132 in which the dielectric multilayer filter layer 132-3 and the fluorescent image pickup image sensor substrate 132-2 are stacked.

In the vertical structure of the stacked image sensor 132 shown in FIG. 5, the vertical structure of a partial region (hereinafter referred to as “pixel region”) in which the pixel portion 1321 is disposed (formed) and the configuration other than the pixel portion 1321 The vertical structure of a part of the area (hereinafter referred to as “area outside the pixel”) in which electrode pads (input / output pads) serving as the elements and terminals of the stacked image sensor 132 are disposed (formed) Is shown.

Here, a more detailed vertical structure in each region of the stacked image sensor 132 will be described. First, the vertical structure of the pixel region in the stacked image sensor 132 will be described. In the pixel region of the laminated image sensor 132, the pixels 1320 are disposed (formed) on the visible image capturing image sensor substrate 132-1 and the fluorescent image capturing image sensor substrate 132-2. In the vertical structure of the pixel region in the stacked image sensor 132 shown in FIG. 5, three pixels 1320 are disposed on each of the visible image capturing image sensor substrate 132-1 and the fluorescent image capturing image sensor substrate 132-2. It shows the case of (formation). Then, in the pixel region of the laminated image sensor 132, the on-chip is directed to the side on which light is incident from the visible image capturing image sensor substrate 132-1, ie, on the upper layer of the visible image capturing image sensor substrate 132-1. The color filter layer 132-6 and the microlens layer 132-7 are further stacked (formed).

The microlens layer 132-7 is a light for imaging visible light, that is, the reflected light (visible light) and fluorescence from the inspection object 901 from which the incident light, that is, the excitation light emitted from the excitation light cut filter 131 has been cut, It is a layer forming the microlenses 13205 to be focused on the respective pixels 1320 disposed on the sensor substrate 132-1 and the fluorescence image capturing image sensor substrate 132-2. In the microlens layer 132-7, the microlenses 13205 are formed at positions corresponding to the respective pixels 1320 disposed (formed) on the visible image capturing image sensor substrate 132-1. In the vertical structure of the pixel region in the laminated image sensor 132 shown in FIG. 5, in the microlens layer 132-7, three corresponding to the pixels 1320 disposed (formed) on the visible image pickup image sensor substrate 132-1 The state in which the micro lens 13205 is formed is schematically shown. Each of the microlenses 13205 corresponds to the reflected light (visible light) and fluorescence incident on the laminated image sensor 132 and the corresponding pixels 1320 disposed on the visible image pickup image sensor substrate 132-1 (more specifically, The light is condensed on a photoelectric conversion element 132011 described later.

The on-chip color filter layer 132-6 forms an on-chip color filter 13204 that transmits light of a predetermined wavelength band and causes the light to enter each pixel 1320 disposed on the visible image capturing image sensor substrate 132-1. It is a layer. In the on-chip color filter layer 132-6, red (R), green (G), or blue (B) at positions corresponding to the respective pixels 1320 disposed on the visible image capturing image sensor substrate 132-1. The on-chip color filter 13204 is formed to transmit light in the wavelength band of (1) (visible light). In the vertical structure of the pixel region in the stacked image sensor 132 shown in FIG. 5, the on-chip color filter layer 132-6 has a wavelength band of any of red (R), green (G), or blue (B). A state in which three on-chip color filters 13204 for transmitting visible light are formed is schematically shown. More specifically, the on-chip color filter layer 132-6 in the pixel region is an on-chip color filter 13204R that transmits visible light in the red (R) wavelength band and visible light in the green (G) wavelength band. A state in which each of the transmitting on-chip color filter 13204G and the on-chip color filter 13204B transmitting visible light in the blue (B) wavelength band is formed is schematically shown. In the layered image sensor 132, the on-chip color filter 13204R, the on-chip color filter 13204G, and the on-chip color filter 13204B are formed in a Bayer arrangement, for example. Each of the on-chip color filters 13204 transmits visible light in one of the wavelength bands collected by the microlens 13205, and the corresponding pixel 1320 disposed on the visible image pickup image sensor substrate 132-1 Specifically, light is incident on a photoelectric conversion element 132011 described later.

Note that each on-chip color filter 13204 transmits light in the near-infrared wavelength band, that is, light in the fluorescence wavelength band, in addition to visible light in the corresponding wavelength band, so an image sensor for capturing a visible image The fluorescence is also incident on each of the pixels 1320 disposed on the substrate 132-1.

In the visible image capturing image sensor substrate 132-1, the pixel 1320 includes the photoelectric conversion element 132011 and the reflective layer 132014 formed in the photoelectric conversion layer 132-11, and the wiring 132012 and light pipe 132013 formed in the wiring layer 132-12. And the function of the pixel 1320 is realized. In the following description, a pixel 1320 (R pixel) in which the on-chip color filter 13204R is formed (pasted) on the light incident side of the visible image pickup image sensor substrate 132-1 is referred to as “R pixel 1320R”. The pixel 1320 (G pixel) in which the on-chip color filter 13204G is formed (pasted) is referred to as "G pixel 1320G", and the pixel 1320 (B pixel) in which the on-chip color filter 13204B is formed (pasted) is referred to as "B pixel 1320B "

Each photoelectric conversion element 132011 generates and accumulates signal charges according to the light intensity of the incident light. More specifically, each photoelectric conversion element 132011 is focused by the microlens 13205 formed in the microlens layer 132-7, and the on-chip color filter 13204 formed in the on-chip color filter layer 132-6. A signal charge corresponding to the light intensity of the reflected light (visible light) transmitted and incident is generated and accumulated.

The wiring 132012 is a wiring that connects the circuit elements of the respective pixels 1320 and the circuit elements formed on the visible image capturing image sensor substrate 132-1. Each of the R pixel 1320R, the G pixel 1320G, and the B pixel 1320B is a pixel signal (analog signal) corresponding to the drive signal from the vertical scanning circuit 13221-1 input through the wiring 132012 formed in the wiring layer 132-12. Is output to the vertical signal line 1327 through the wiring 132012.

Note that among the incident reflected light (visible light) and fluorescence, the photoelectric conversion element 132011 transmits part of light in the visible light wavelength band and light in the fluorescence wavelength band that were not used to generate signal charges. Do. In other words, the photoelectric conversion element 132011 is an optical filter that absorbs and attenuates the light of the wavelength band of visible light used for generating the signal charge among the incident reflected light (visible light) and the fluorescence, and transmits only the fluorescence As well as functioning.

A part of visible light and fluorescence transmitted through the photoelectric conversion element 132011 is guided by the light pipe 132013 formed in the wiring layer 132-12 and emitted to the side of the image sensor substrate 132-2 for capturing a fluorescent image. The light pipe 132013 is an optical path for guiding light transmitted through the photoelectric conversion element 132011 and incident from the photoelectric conversion layer 132-11 side to the protective film 132-4 side, that is, to the fluorescent image pickup image sensor substrate 132-2 side. . In the light pipe 132013, the photoelectric conversion element is formed by providing the area of the opening so that the wiring 132012 formed in the wiring layer 132-12 does not overlap the area of the photoelectric conversion element 132011 formed in the photoelectric conversion layer 132-11. 132011 secures a light transmission area for light transmission. Then, the light pipe 132013 is made of a high refractive index material such as silicon nitride (Si ₃ N ₄ ) having a larger refractive index of light than the periphery of the light transmission region in the wiring layer 132-12 in the secured light transmission region. Formed by filling. The light incident on the light pipe 132013 passes through the inside of the light pipe 132013, and is efficiently emitted to the side of the image sensor substrate 132-2 for capturing a fluorescent light image.

Among the reflected light (visible light) and the fluorescence incident on the photoelectric conversion element 132011, the fluorescence has a long wavelength, so the influence of diffraction is large and the diffusion of light is fast (the amount of diffusion of light is large). is there. Therefore, when the distance between the pixels 1320 in the stacked image sensor 132, ie, the so-called pixel pitch is narrowed, the fluorescence transmitted through the on-chip color filter 13204 and incident on the visible image pickup image sensor substrate 132-1 Diffusion of light proceeds in the photoelectric conversion layer 132-11 from the time of incidence on the photoelectric conversion element 13 2011. Then, as the light travels due to the interference with the fluorescence in which diffusion has progressed in the adjacent (adjacent) pixel, the fluorescence in the photoelectric conversion layer 132-11 has advanced (the light The position where the light intensity distribution peaks gradually shifts toward the position of the wiring in the wiring layer 132-12 as the position 132-12 is approached. For this reason, much of the fluorescence is reflected on the wiring 132012 in the wiring layer 132-12, and can not be transmitted through the wiring layer 132-12, and the fluorescence is guided to the image sensor substrate 132-2 for capturing a fluorescent image. It is believed that the amount of light of More specifically, since fluorescence is light in the near-infrared wavelength band (near-infrared light), for example, if the pixel pitch of the pixels 1320 is narrower than about 2 um, the influence of diffraction starts to appear significantly, and light It is considered that the light amount of the fluorescence guided to the side of the image sensor substrate 132-2 for capturing a fluorescent image by the pipe 132013 is reduced by an amount affected by the diffraction. Therefore, in the multilayer image sensor 132, the reflective layer 132014 is formed between the pixels 1320 formed on the visible image capturing image sensor substrate 132-1. More specifically, in the multi-layer image sensor 132, even when the pixel pitch of the pixels 1320 is set to a distance at which the influence of diffraction of fluorescence is large, the amount of fluorescence incident on the light pipe 132013 decreases. In the photoelectric conversion layer 132-11 constituting the visible image capturing image sensor substrate 132-1, the reflection layer 132014 is formed between the photoelectric conversion elements 132011 so as not to be present.

The reflective layer 132014 is a reflective film that reflects fluorescence that diffuses beyond the diffraction limit in the photoelectric conversion layer 132-11. Reflective layer 132,014 are adjacent in the photoelectric conversion layer 132-11 forms a depression or more from the surface of the depth 1um between the photoelectric conversion elements 132 011, for example, such as silicon dioxide (SiO _2), the photoelectric conversion layer 132 - It is filled with a low refractive index material having a light refractive index smaller than 11 and formed. As a result, in the fluorescent light transmitted through the photoelectric conversion element 132011, light diffused beyond the diffraction limit is reflected by the reflective layer 132014 and condensed on the light pipe 132013, and a decrease in light quantity is suppressed, so that the light pipe 132013 is efficiently used. It is incident on Then, the fluorescence incident to the light pipe 132013 is emitted to the side of the image sensor substrate 132-2 for imaging a fluorescence image.

The reflective layer 132014 may be formed so as to surround the periphery of each of the photoelectric conversion elements 132011, for example. However, the reflective layer 132014 may not necessarily surround the periphery of the photoelectric conversion element 132011 without a gap. The reflective layer 132014 does not significantly reduce the ability to reflect fluorescence that diffuses beyond the diffraction limit by opening a slight gap between adjacent photoelectric conversion elements 132011, Allow clearance.

The structure of the reflective layer 132014 is a deeper depression than the conventional Shallow Trench Isolation (STI) structure.

Then, part of visible light and fluorescence transmitted through the photoelectric conversion element 132011 led by the light pipe 132013 is incident on the protective film 132-4 and the dielectric multilayer filter layer 132-3, and the dielectric multilayer filter layer Visible light is attenuated by 132-3. More specifically, as described above, for example, a thin film layer of silicon dioxide (SiO ₂ ) and a thin film layer of titanium oxide (TiO ₂ ) are alternately stacked on the dielectric multilayer filter layer 132-3. As a result, the dielectric multilayer filter 13203 is formed. The dielectric multilayer film filter 13203 is a reflected light (visible light) and a fluorescence guided by the light pipe 132013 corresponding to each pixel 1320 formed in the wiring layer 132-12 of the visible image pickup image sensor substrate 132-1. Among them, only light in the visible light wavelength band is reflected or absorbed and attenuated, and light in the fluorescence wavelength band is transmitted. Thereby, only the fluorescence transmitted through the photoelectric conversion element 132011 is incident on the corresponding pixel 1320 (more specifically, the photoelectric conversion element 132021 described later) disposed on the fluorescence image pickup image sensor substrate 132-2. . The protective film 132-4 emits nothing to the incident light, as it is, to the dielectric multilayer filter layer 132-3.

In the image sensor substrate 132-2 for capturing a fluorescent image, the function of the pixel 1320 is realized by the photoelectric conversion element 132021 formed in the photoelectric conversion layer 132-21 and the wiring 132202 formed in the wiring layer 132-22. Be done. In the following description, a pixel 1320 (fluorescent pixel) disposed (formed) on the fluorescent image pickup image sensor substrate 132-2 is referred to as “fluorescent pixel 1320 IR”.

Each photoelectric conversion element 132021 generates and accumulates a signal charge according to the light intensity of the incident light. More specifically, each photoelectric conversion element 132021 is incident on the image sensor substrate 132-1 for picking up a visible image from the microlens layer 132-7 through the on-chip color filter layer 132-6 and is used for picking up a visible image. A signal charge corresponding to the light intensity of the fluorescence transmitted through the light pipe 132013 and the dielectric multilayer filter layer 132-3 of the corresponding pixel 1320 formed on the image sensor substrate 132-1 is generated and accumulated.

The wiring 132022 is a wiring for connecting the circuit elements of the respective fluorescent pixels 1320 IR and the circuit elements formed on the image sensor substrate 132-2 for fluorescent image capturing. Each fluorescent pixel 1320 IR converts a pixel signal (analog signal) according to the drive signal from the vertical scanning circuit 1322-1 input through the wiring 132022 formed in the wiring layer 132-22 into a vertical signal line through the wiring 132022 Output.

With such a structure, in the pixel region in the stacked image sensor 132, the pixels 1320 are arranged (formed) at a pixel pitch at which the influence of diffraction largely appears on the fluorescence transmitted through the visible image capturing image sensor substrate 132-1. Even in this case, the decrease in the amount of fluorescence incident on the light pipe 132013, that is, the amount of fluorescence incident on the fluorescence image pickup image sensor substrate 132-2 is suppressed. Accordingly, in the stacked image sensor 132, the size (area) of the pixel 1320 can be reduced, that is, the size necessary for the pixel region can be reduced.

Subsequently, the vertical structure of the non-pixel area in the stacked image sensor 132 will be described. Electrode pads (input / output pads) serving as respective terminals for the laminated image sensor 132 to input / output signals to / from the outside, and an image sensor for picking up a visible image in an area outside the pixel of the laminated image sensor 132. A signal line for electrically connecting a component arranged (formed) on the substrate 132-1 and a component arranged (formed) on the image sensor substrate 132-2 for fluorescent image capturing is arranged (formed).

As described above, in the multi-layer image sensor 132, the components common to the visible image capturing image sensor and the fluorescent image capturing image sensor are the visible image capturing image sensor substrate 132-1 or the fluorescent image capturing image It is disposed on any of the sensor substrates 132-2. Therefore, the signal lines exchanged between the visible image pickup image sensor substrate 132-1 and the fluorescent image pickup image sensor substrate 132-2 are the wiring layers 132-12 of the visible image pickup image sensor substrate 132-1. And the wiring 132202 formed in the wiring layer 132-22 of the image sensor substrate 132-2 for fluorescent image capturing.

For example, the connection between the serial access memory 1325 and the timing generator 13242 in the control circuit 1324 shown in FIG. 4 and the connection between the timing generator 13242 and the vertical scanning circuit 13221-2 and the horizontal scanning circuit 1322-2 are different from the wiring 132012. It is connected to the wiring 132022. In the vertical structure of the region outside the pixel in the multilayer image sensor 132 shown in FIG. 5, the photoelectric conversion layer 132-21, the dielectric multilayer filter layer 132-3, and the protective film of the fluorescent image pickup image sensor substrate 132-2 Through-silicon through electrode (Through-Silicon-Via: TSV) leading out wiring 132202 formed in wiring layer 132-22 on the upper surface (surface) of the protective film 132-4 through which light penetrates 132-4. The state in which 132023 is formed is schematically shown. Further, in the vertical structure of the region outside the pixel in the stacked image sensor 132 shown in FIG. 5, the light is emitted from the wiring 132012 formed in the wiring layer 132-12 of the visible image capturing image sensor substrate 132-1. The state which forms the back surface electrode 132016 withdraw | derived on the lower surface (back surface) of these is shown typically. The vertical structure of the region outside the pixel in the stacked image sensor 132 shown in FIG. 5 schematically shows a state in which the silicon through electrode 132023 and the back electrode 132016 are connected. Thus, in the multilayer image sensor 132, the wiring 132012 formed in the wiring layer 132-12 of the visible image pickup image sensor substrate 132-1 and the wiring layer 132-22 of the fluorescent image pickup image sensor substrate 132-2 The wiring 132202 formed in the above is connected through the photoelectric conversion layer 132-21, the dielectric multilayer filter layer 132-3, and the protective film 132-4.

Further, as described above, in the stacked image sensor 132, electrode pads for inputting and outputting signals to and from the outside are disposed only on the visible image capturing image sensor substrate 132-1. Therefore, the signal lines exchanged between the components disposed on the fluorescent image pickup image sensor substrate 132-2 in the stacked image sensor 132 and the outside pass through the visible image pickup image sensor substrate 132-1. Then, it is connected to the wiring 132022 formed in the wiring layer 132-22 of the fluorescence image pickup image sensor substrate 132-2 (through).

For example, a master input to the power supply (power supply VDD1 and ground GND1, power supply VDD2 and ground GND2) of the fluorescence image pickup image sensor substrate 132-2 shown in FIG. 4 or the fluorescence image pickup image sensor substrate 132-2 The clock MCLK is connected to the wiring 132022 through (through) the inside of the visible image capturing image sensor substrate 132-1. Also, for example, the controller clock SCK, the SPI trigger signal CS, the SPI input signal MOSI, and the SPI output signal MISO input to the serial access memory 1325 shown in FIG. Through the inside (through), it connects to the wiring 132022. In addition to the silicon through electrode 132023, the vertical structure of the region outside the pixel in the multilayer image sensor 132 shown in FIG. 5 is visible through the photoelectric conversion layer 132-11 of the visible image pickup image sensor substrate 132-1. In the image sensor substrate 132-1 for image pickup, a state is schematically shown where a silicon penetration electrode 132015 is formed on the upper surface (surface) on the side where light is incident, for drawing out the wiring 132012 formed in the wiring layer 132-12 ing. Further, in the vertical structure of the region outside the pixel in the laminated image sensor 132 shown in FIG. 5, the edge on the upper surface (surface) side where light is incident on the visible image pickup image sensor substrate 132-1 in the silicon through electrode 132015 A state in which a wire bonding pad 132017 which is an electrode pad (input / output pad) for connecting a signal of the stacked image sensor 132 to the outside is schematically shown. The wire bonding pad 132017 is formed on the periphery of the upper surface (surface) of the side on which light is incident on the visible image pickup image sensor substrate 132-1. Thus, in the multilayer image sensor 132, the wiring 132022 formed on the wiring layer 132-22 of the fluorescent image pickup image sensor substrate 132-2 and the photoelectric conversion layer 132- of the visible image pickup image sensor substrate 132-1. And the wire bonding pad 132017 formed on the upper surface of the photoelectric conversion layer 132-21, the dielectric multilayer film filter layer 132-3, the protective film 132-4, the wiring 132012, and the photoelectric conversion layer 132-11. Connected

With such a structure, in an area outside the pixel in the stacked image sensor 132, a signal for exchanging signals with the outside through an electrode pad (input / output pad) disposed only on the visible image pickup image sensor substrate 132-1 is fluorescence image It is connected to the components disposed on the imaging image sensor substrate 132-2. As a result, in the stacked image sensor 132, the number of wire bonding pads 132017 arranged (formed) in the area outside the pixel can be reduced, and the chip area of the stacked image sensor 132, that is, the mounting area can be reduced. .

Due to the above-described structure, in the stacked image sensor 132, the arrangement (formation) of the pixels 1320 at a pixel pitch at which the influence of diffraction largely appears on the fluorescence transmitted through the visible image capturing image sensor substrate 132-1; By making the arrangement of the pads (input / output pads) only on the visible image pickup image sensor substrate 132-1, the miniaturization of the multilayer image sensor 132 is realized.

Next, the effect of the reflective layer 132014 in the stacked image sensor 132 will be described. FIG. 6 is a view showing an example of the distribution characteristic of the light intensity in the solid-state imaging device (stacked image sensor 132) provided in the fluorescence observation endoscope apparatus 1 of the embodiment of the present invention. FIG. 6 shows an example of the result of optical simulation of the distribution of light intensity (light intensity) when the pixel pitch of the pixels 1320 arranged (formed) in the stacked image sensor 132 is 0.9 μm.

FIG. 6A schematically shows an example of the vertical structure of the pixel region of the laminated image sensor 132 shown in FIG. Further, in (b) of FIG. 6, (c) of FIG. 6, and (d) of FIG. 6, the intensity (light intensity) of light of fluorescence f in the wavelength band of fluorescence in the pixel region of the laminated image sensor 132. 7 shows an example of the result of optical simulation of the distribution of. More specifically, in (a) of FIG. 6, the vertical direction in the case where two R pixels 1320R and two G pixels 1320G are alternately arranged in the pixel region of the stacked image sensor 132 shown in FIG. The structure is schematically shown. The vertical structure of the pixel area of the stacked image sensor 132 shown in FIG. 6A is the vertical structure of the pixel area of the stacked image sensor 132 in which the arranged pixels 1320 are shown in FIG. And the detailed description is omitted.

Further, in (b) of FIG. 6, in the pixel region of the stacked image sensor 132 shown in (a) of FIG. 6, the photoelectric conversion layer 132-11 constituting the visible image capturing image sensor substrate 132-1 is used. An example of a result of performing optical simulation of distribution of light intensity of fluorescence f by the side of the upper surface (surface) which light enters is shown. Further, in (c) of FIG. 6, in the pixel region of the stacked image sensor 132 shown in (a) of FIG. 6, the photoelectric conversion layer 132-11 constituting the visible image capturing image sensor substrate 132-1 is An example of a result of performing optical simulation of distribution of light intensity of fluorescence f by the side of the undersurface (back side) which light emits is shown. Further, in (d) of FIG. 6, as a reference, a photoelectric conversion layer 132 constituting an image sensor substrate 132-1 for capturing a visible image in the pixel region of the laminated image sensor 132 shown in (a) of FIG. An example of the result of optical simulation of the light intensity distribution of the fluorescence f on the lower surface (rear surface) side from which light is emitted when the reflective layer 132014 is not formed at −11 is shown. In (b) of FIG. 6, (c) of FIG. 6, and (d) of FIG. 6, with the pixel pitch as the horizontal axis, the relative magnitude (intensity) of light intensity is shown as the vertical axis. There is.

As shown in (b) of FIG. 6, the fluorescence incident to the pixel 1320 on each surface of the photoelectric conversion layer 132-11 (silicon substrate) on the light incident side to the visible image pickup image sensor substrate 132-1 The distribution of the light intensity of f is maximum (peak) near the center of the position where the R pixel 1320R and the pixel 1320G are arranged, that is, at the center position which is the focal point of the microlens 13205 of each pixel 1320. Further, as shown in (c) of FIG. 6, in the surface of the photoelectric conversion layer 132-11 (silicon substrate) on the side from which the light incident on the visible image pickup image sensor substrate 132-1 is transmitted and emitted. The distribution of the light intensity of the fluorescence f transmitted through the pixel 1320 is also the same as the distribution of the light intensity of the fluorescence f on the side where the light is incident on the photoelectric conversion layer 132-11 shown in (b) of FIG. It peaks near the center of the position where the pixel 1320R and the pixel 1320G are disposed.

When the reflective layer 132014 is not formed on the photoelectric conversion layer 132-11, as shown in (d) of FIG. 6, light incident on the visible image pickup image sensor substrate 132-1 is transmitted. The position where the light intensity distribution of the fluorescent light f peaks on the surface of the photoelectric conversion layer 132-11 (silicon substrate) on the side to be emitted is the position between the positions where the respective pixels 1320 are arranged, that is, , And the position of the boundary with the adjacent pixel 1320. That is, when the reflective layer 132014 is not formed in the photoelectric conversion layer 132-11, the position at which the light intensity distribution of the fluorescence f transmitted through each pixel 1320 peaks is largely from the central position of the corresponding microlens 13205 It has slipped. This means that the fluorescence f, which is light with a long wavelength, diffuses beyond the diffraction limit by the time it is transmitted through the photoelectric conversion layer 132-11, and mutually interacts with the fluorescence f that should be transmitted through the adjacent pixel 1320. It is due to having interfered. In this case, the fluorescence f transmitted through the photoelectric conversion layer 132-11 is blocked by the wiring 132012 formed in the wiring layer 132-12, and is not efficiently incident on the light pipe 132013, so that an image sensor for fluorescence image pickup The light amount of the fluorescent light f incident on the substrate 132-2 decreases. Then, in the fluorescence observation endoscope apparatus 1 in which the stacked image sensor 132 in which the reflective layer 132014 is not formed in the photoelectric conversion layer 132-11 is mounted, the fluorescence image including the test object 901 generated by the image processing unit 33 is used. It is not possible to suppress the decrease in image quality and resolution.

On the other hand, in the laminated image sensor 132, as described above, the position at which the distribution of the light intensity of the fluorescence f on the light incident side to the photoelectric conversion layer 132-11 peaks and the photoelectric conversion layer 132-11. The light intensity distribution of the fluorescence f on the side from which light is emitted through the light emission peak is near the center of the position where the respective pixels 1320 are disposed. This is because, in the laminated image sensor 132, the reflection layer 132014 formed on the photoelectric conversion layer 132-11 of the visible image pickup image sensor substrate 132-1 has a diffraction limit in the photoelectric conversion layer 132-11 before transmission. It is by condensing the fluorescence f which is diffused to the light pipe 132013. Thereby, in the stacked image sensor 132, the fluorescence f transmitted through the photoelectric conversion layer 132-11 is efficiently incident on the light pipe 132013, that is, the amount of light is reduced due to the influence of diffraction, and thus the fluorescence image The light is incident on the image sensor substrate 132-2 for imaging. That is, in the stacked image sensor 132, the fluorescence f transmitted through the visible image capturing image sensor substrate 132-1 is transmitted from the back surface corresponding to the position where the respective pixels 1320 are disposed. Send to 2 Thereby, in the laminated image sensor 132, the fluorescent pixel 1320IR disposed on the fluorescent image pickup image sensor substrate 132-2 outputs parallel RAW data of the fluorescent light image pickup signal in which the fluorescent light f with a sufficient light amount is exposed. Can. By this, in the fluorescence observation endoscope apparatus 1, it is possible to suppress the deterioration of the image quality and the resolution in the fluorescence image generated by the image processing unit 33 based on the parallel RAW data of the fluorescence image pickup signal output by the laminated image sensor 132. Can. That is, in the fluorescence observation endoscope apparatus 1, it is possible to generate a fluorescence image including the inspection object 901 without deterioration of the image quality and the resolution.

As described above, in the stacked image sensor 132, the reflection layer 132014 is formed in the photoelectric conversion layer 132-11 constituting the visible image capturing image sensor substrate 132-1 to cause diffusion beyond the diffraction limit. The fluorescence f can be focused on the light pipe 132013, and a fluorescence image pickup signal for generating a fluorescence image in which the deterioration of the image quality is suppressed can be output.

Next, a method of manufacturing the multilayer image sensor 132 (manufacturing process) will be described. 7 to 9 are cross-sectional views for explaining an outline of a method of manufacturing a solid-state imaging device (laminated image sensor 132) provided in the fluorescence observation endoscope apparatus 1 according to the embodiment of the present invention. FIG. 7 shows an outline of a manufacturing method (manufacturing process) of the visible image capturing image sensor substrate 132-1 constituting the stacked image sensor 132. Further, FIG. 8 shows an outline of a method of manufacturing a fluorescent image pickup image sensor substrate 132-2 constituting the laminated image sensor 132 (manufacturing process). Further, FIG. 9 shows an outline of a manufacturing method (manufacturing process) of a laminated type image sensor 132 in which an image sensor substrate 132-1 for visible image pickup and an image sensor substrate 132-2 for fluorescent image pickup are laminated. .

In the manufacturing method (manufacturing process) of the visible image pickup image sensor substrate 132-1 and the fluorescent image pickup image sensor substrate 132-2 constituting the stacked image sensor 132, the photoelectric conversion element is formed in the photoelectric conversion layer. The manufacturing method (manufacturing process) and the manufacturing method (manufacturing process) for forming the wiring in the wiring layer are the same as the existing manufacturing method (manufacturing process) in the image sensor. Therefore, in the following description, in order to facilitate the description, it relates to a method (manufacturing process) of photoelectric conversion elements and wires in the visible image capturing image sensor substrate 132-1 and the fluorescent image capturing image sensor substrate 132-2. Detailed description is omitted.

First, a manufacturing method (manufacturing process) of the visible image pickup image sensor substrate 132-1 constituting the stacked type image sensor 132 shown in FIG. 7, and the visible image pickup image sensor substrate 132-1 and the fluorescent image pickup image The manufacturing method (manufacturing process) of laminating the sensor substrate 132-2 will be described.

(Step 1)
As shown in (a) of FIG. 7, an image sensor substrate 132-1 for imaging a visible image on which the light pipe 132013 is formed is manufactured. More specifically, first, the photoelectric conversion element 132011, that is, the photoelectric conversion layer 132-11 is formed on a silicon (Si) substrate to be an image sensor substrate 132-1 for capturing a visible image. After that, a region (light transmission region) of an opening for emitting light is provided so as not to overlap with the region of the photoelectric conversion element 132011 formed in the photoelectric conversion layer 132-11, that is, the light pipe 132013 is formed. A region is provided to form a wiring 132012 in the wiring layer 132-12. In the light transmission area, when the visible image pickup image sensor substrate 132-1 is considered as a front-side illumination (FSI) type solid-state imaging device, the wiring layer 132 on the light incident side to the photoelectric conversion element 132011. It can also be said that the region is an opening formed to allow light to enter the photoelectric conversion element 132011 at -12. Then, the light transmission region provided in the wiring layer 132-12 is filled with a high refractive index material such as silicon nitride (Si ₃ N ₄ ), for example, to form a light pipe 132013.

(Step 2)
As shown in (b) of FIG. 7, a back electrode 132016 is formed for extracting the wiring 132012 formed in the wiring layer 132-12 of the visible image pickup image sensor substrate 132-1. More specifically, the back electrode 132016 connected to the wiring 132012 in the wiring layer 132-12 formed in step 1 is formed, and the surface on which the back electrode 132016 is formed is planarized by chemical mechanical polishing (CMP) or the like. Do. The surface on which the back electrode 132016 flattened in the process 2 is formed is a bonding surface JS-1 of the visible image pickup image sensor substrate 132-1.

According to such a manufacturing method (manufacturing process), the visible image capturing image sensor substrate 132-1 having the light pipe 132013 and the back surface electrode 132016, which constitutes the stacked image sensor 132, is manufactured.

Subsequently, a manufacturing method (manufacturing process) of the fluorescent image pickup image sensor substrate 132-2 constituting the laminated image sensor 132 shown in FIG. 8 will be described.

(Step 3)
As shown in (a) of FIG. 8, it is laminated on a fluorescent image pickup image sensor substrate 132-2 configured as a back-side illumination (Backside Illumination: BSI) type solid-state imaging device, that is, a support substrate 132-5 The dielectric multilayer film filter layer 132-3 is formed (laminated) on the fluorescence image pickup image sensor substrate 132-2. More specifically, first, the surface on the light incident side (hereinafter referred to as “light receiving surface”) of the fluorescent image pickup image sensor substrate 132-2 is formed by chemical mechanical polishing (CMP) or the like. Flatten. Thereafter, a silicon dioxide (SiO ₂ ) thin film layer 132031 and a titanium oxide (TiO ₂ ) thin film are formed on the planarized light receiving surface of the image sensor substrate 132-2 for fluorescent image imaging by ion assisted deposition (IAD) or the like. The layers 132032 are alternately formed (laminated), and the dielectric multilayer filter 13203 is formed (laminated) in the dielectric multilayer filter layer 132-3.

(Step 4)
As shown in FIG. 8B, the protective film 132-4 is formed (laminated) on the formed (laminated) dielectric multilayer filter layer 132-3. More specifically, the surface of the dielectric multilayer film filter layer 132-3 formed (laminated) in the step 3 opposite to the light receiving surface of the image sensor substrate 132-2 for capturing a fluorescent image, that is, the dielectric multilayer film filter A protective film 132-4 is formed (laminated) on the surface of the layer 132-3 on which light is incident by chemical vapor deposition (CVD) or the like. The thickness of the protective film 132-4 to form in step 4, at least a dielectric respective thin film layers forming a multilayer filter layer 132-3 (silicon dioxide (SiO ₂₎ thin film layer 132,031 or titanium oxide (TiO ₂ ) Thicker than the thickness of the thin film layer 132032).

(Step 5)
As shown in FIG. 8C, through holes 132023a are formed in the fluorescence image pickup image sensor substrate 132-2. More specifically, the dielectric multilayer filter layer 132-3 and the protective film 132-4 formed (stacked) in the steps 3 and 4 and the photoelectric conversion layer 132 of the image sensor substrate 132-2 for capturing a fluorescent image 21 are formed by photolithography and etching to reach through-holes 132023a which reach through the through-holes 21 and reach the wiring 132022 formed in the wiring layer 132-22.

(Step 6)
As shown in (d) of FIG. 8, the silicon through electrode 132023 is formed on the fluorescence image pickup image sensor substrate 132-2. More specifically, the wiring 132022 formed in the wiring layer 132-22 of the image sensor substrate 1322 for capturing a fluorescent image is drawn to the through hole 132023a formed in step 5 by chemical vapor deposition (CVD) or the like. A metal material is filled to form through silicon vias 132023.

(Step 7)
As shown in (e) of FIG. 8, the fluorescent image pickup image sensor substrate 132-2 on which the silicon through electrode 132023 is formed is planarized. More specifically, the surface filled with the metal material for forming the silicon through electrode 132023 in step 6, that is, the surface on the light receiving surface side of the fluorescent image pickup image sensor substrate 132-2, is subjected to chemical mechanical polishing (CMP) or the like. Flatten by. The surface on the light receiving surface side of the fluorescence image pickup image sensor substrate 132-2 flattened in step 7 is taken as the bonding surface JS-2 of the fluorescence image pickup image sensor substrate 132-2.

In the planarization in the step 7, the silicon through electrode 132023 is polished including the protective film 132-4, that is, the protective film 132-4 is also polished together with the silicon through electrode 132023. Thereby, the thickness of the protective film 132-4 becomes thinner than the thickness formed in the process 4. However, in the planarization in the step 7, since the protective film 132-4 formed in the step 4 is not entirely polished, the characteristics of the dielectric multilayer filter 13203 formed in the step 3 are not affected. Also, the difference in thickness of the protective film 132-4 does not affect the characteristics of the dielectric multilayer filter 13203.

According to such a manufacturing method (manufacturing process), the fluorescent image pickup image sensor substrate 132-2 having the silicon through electrode 132023 which forms the laminated image sensor 132 is manufactured.

In the layered image sensor 132, each of the visible image capturing image sensor substrate 132-1 and the fluorescent image capturing image sensor substrate 132-2 is separately manufactured, and thereafter, the respective image sensor substrates are stacked. To manufacture the final stacked image sensor 132. Therefore, a manufacturing process (process 1 and process 2) for manufacturing the visible image capturing image sensor substrate 132-1 and a manufacturing process (process 3 to process 7) for manufacturing the fluorescent image capturing image sensor substrate 132-2 May be done in parallel.

Subsequently, a method of manufacturing the laminated image sensor 132 shown in FIG. 9 (manufacturing process) will be described.

(Step 8)
As shown in FIG. 9A, the visible image pickup image sensor substrate 132-1 and the fluorescent image pickup image sensor substrate 132-2 are stacked. More specifically, the bonding surface JS-1 of the visible image capturing image sensor substrate 132-1 and the bonding surface JS-2 of the fluorescent image capturing image sensor substrate 132-2 are stacked to face each other. At this time, in step 8, the position of the back electrode 132016 formed on the visible image pickup image sensor substrate 132-1 and the position of the silicon through electrode 132023 formed on the fluorescent image pickup image sensor substrate 132-2 are aligned. The bonding surface JS-1 and the bonding surface JS-2 are made to face each other and stacked. As a result, the back electrode 132016 formed on the visible image pickup image sensor substrate 132-1 and the silicon through electrode 132023 formed on the fluorescent image pickup image sensor substrate 132-2 are physically bonded at the bonding surface JS. , And electrically connected.

(Step 9)
As shown in (b) of FIG. 9, the silicon substrate of the visible image pickup image sensor substrate 132-1 is thinned, and the visible image pickup image sensor substrate 132-1 is configured as a backside illumination type solid-state imaging device. Let More specifically, the thickness of the silicon substrate on the side where the back surface electrode 132016 is not formed in the visible image pickup image sensor substrate 132-1 is, for example, a photoelectric formed by chemical mechanical polishing (CMP) or etching. The conversion element 132011 is thin enough to allow light to enter. As a result, light is incident on the photoelectric conversion element 132011 from the back surface of the silicon substrate after thinning the visible image pickup image sensor substrate 132-1, that is, the back surface of the visible image pickup image sensor substrate 132-1 is the light receiving surface It is configured as a back-illuminated solid-state imaging device.

(Step 10)
As shown in FIG. 9C, the reflective layer 132014 is formed on the silicon substrate thinned in the visible image pickup image sensor substrate 132-1. More specifically, first, the silicon substrate thinned in the visible image capturing image sensor substrate 132-1, that is, between the respective photoelectric conversion elements 132011 formed in the photoelectric conversion layer 132-11, is subjected to photolithography. A recess of 1 μm or more in depth is formed from the surface of the photoelectric conversion layer 132-11 by etching and After that, the hollow formed in the photoelectric conversion layer 132-11 is filled with a low refractive index material such as silicon dioxide (SiO ₂ ) by chemical vapor deposition (CVD) or the like to form a reflective layer 132014.

In step 10, the surface of the photoelectric conversion layer 132-11 (silicon substrate) of the visible image pickup image sensor substrate 132-1 filled with the low refractive index material for forming the reflective layer 132014 is chemically mechanical polished ( It may be planarized by CMP or the like. In the planarization at this time, the photoelectric conversion layer 132-11 (silicon substrate) is polished including the reflective layer 132014, that is, the photoelectric conversion layer 132-11 is polished by polishing the reflective layer 132014 and the silicon substrate together. The entire surface may be flattened. In this case, the thickness of the photoelectric conversion layer 132-11 (silicon substrate) of the visible image pickup image sensor substrate 132-1 is thinner than the thickness when the silicon substrate is thinned in step 9. For this reason, in the process 9, in view of the fact that the photoelectric conversion layer 132-11 becomes thinner by planarization after forming the reflective layer 132014 in the process 10, the silicon substrate is thinned in a state in which the thickness is increased accordingly. May be

(Step 11)
As shown in (d) of FIG. 9, the on-chip color filter layer 132-6 and the microlens layer 132-7, and the wire bonding are provided on the photoelectric conversion layer 132-11 of the visible image pickup image sensor substrate 132-1. The pad 132017 is formed. More specifically, first, a wire bonding pad 132017 is formed on the light receiving surface of the visible image capturing image sensor substrate 132-1. In the formation of the pad 132017 for wire bonding, first, a through hole which penetrates the photoelectric conversion layer 132-11 and reaches the wiring 132012 formed in the wiring layer 132-12 is formed by photolithography and etching, A silicon through electrode 132015 filled with a metal material for extracting the wiring 132012 formed in the wiring layer 132-12 is formed by chemical vapor deposition (CVD) or the like. Thereafter, a wire bonding pad 132017 is formed by chemical vapor deposition (CVD) or the like, which is connected to the silicon through electrode 132015, that is, connected to the wiring 132012 in the wiring layer 132-12. Subsequently, an on-chip color filter layer 132-6 in which on-chip color filters 13204 are disposed at positions corresponding to the respective photoelectric conversion elements 132011 is formed. At this time, the on-chip color filter 13204R, the on-chip color filter 13204G, and the on-chip color filter 13204B are formed in the on-chip color filter layer 132-6, for example, in a Bayer arrangement. Finally, a microlens layer 132-7 is formed in which the microlenses 13205 are disposed at positions corresponding to the on-chip color filters 13204 of the on-chip color filter layers 132-6.

By such a manufacturing method (manufacturing process), a final laminated type image sensor 132 in which the visible image pickup image sensor substrate 132-1 and the fluorescent image pickup image sensor substrate 132-2 are laminated is manufactured.

According to the embodiment, the first photoelectric conversion layer (photoelectric conversion layer) in which the first photoelectric conversion element (photoelectric conversion element 132011) for photoelectrically converting the incident light (visible light and visible light among the visible light) is formed 132-11) and the first wiring layer (wiring layer 132-12) in which the first wiring (wiring 132012) is formed on the surface opposite to the surface on which light is incident to the photoelectric conversion element 132011). The first semiconductor substrate (visible image pickup image sensor substrate 132-1) formed and the layer on the side opposite to the side where light is incident on the visible image pickup image sensor substrate 132-1 are visible images A second photoelectric conversion layer (photoelectric conversion layer 132-21) in which a second photoelectric conversion element (photoelectric conversion element 132021) for photoelectrically converting light (fluorescent light) transmitted through the imaging image sensor substrate 132-1 is formed; And And a second semiconductor substrate (fluorescent image pickup image sensor substrate 132-2) on which a second wiring layer (wiring layer 132-22) on which the wiring (wiring 132202) is formed is formed, and an image for visible image pickup A dielectric multilayer filter (a dielectric multilayer filter 13203 formed on the dielectric multilayer filter layer 132-3) disposed between the sensor substrate 132-1 and the fluorescence image pickup image sensor substrate 132-2 , in the photoelectric conversion layer 132-11 is formed between the photoelectric conversion elements 132 011, the refractive index of the light is smaller than the photoelectric conversion layer 132-11 low refractive index material (e.g., silicon dioxide (SiO _2), etc.) is filled And the light transmission layer formed at the position corresponding to the photoelectric conversion element 132011 in the reflection layer (reflection layer 132014) formed by A solid-state imaging device (stacked image sensor 132) is configured to have an over area (an area of an opening for light incidence).

Further, according to the embodiment, the light transmission region is a light pipe (for example, silicon nitride (Si ₃ N ₄ ) or the like) having a light refractive index larger than that of the wiring layer 132-12 (eg, silicon nitride (Si ₃ N ₄ )). A stacked image sensor 132 having a light pipe 132013) is configured.

Further, according to the embodiment, an electrode pad (silicon (silicon) which is formed on the visible image pickup image sensor substrate 132-1 and which penetrates the photoelectric conversion layer 132-11 to conduct a signal between the wiring 132012 and the outside. Stacked image having a through electrode 132015 and a wire bonding pad 132017) and a through electrode (silicon through electrode 132023) which penetrates the dielectric multilayer filter 13203 and electrically connects the wiring 132012 and the wiring 132022 The sensor 132 is configured.

Further, according to the embodiment, the power (power VDD1 or power VDD2), ground (ground GND1 or ground GND2) supplied to the corresponding wire bonding pad 132017 of the visible image capturing image sensor substrate 132-1, and the master A laminated image sensor 132 configured to connect an external signal of one of the clocks (master clock MCLK) to the wiring 132022 via the silicon through electrode 132023 and supply the signal to the fluorescence image pickup image sensor substrate 132-2 Be done.

Further, according to the embodiment, the wiring 132012 or the wiring 132022 is formed on the semiconductor substrate (image sensor substrate) of at least one of the visible image pickup image sensor substrate 132-1 and the fluorescent image pickup image sensor substrate 132-2. Control the photoelectric conversion element 132011 and the photoelectric conversion element 132021 via the photoelectric conversion element 132011 and the photoelectric conversion element 132021 (pixel signal, visible image pickup signal according to pixel signal, fluorescent image pickup signal, etc.) A peripheral circuit (readout unit 1322, vertical scanning circuit 13221, horizontal scanning circuit 13222, analog / digital conversion unit 1323, analog / digital converter, and the like) which outputs an imaging signal, parallel RAW data, serial RAW data, and the like to the wiring 132012 or the wiring 132022 A peripheral circuit formed on a visible image pickup image sensor substrate 132-1 and a fluorescent image, including a digital conversion circuit 13230, a control circuit 1324, a clock generator 13241, a timing generator 13242, a serial access memory 1325, and a serializer 1326). Among the peripheral circuits formed on the imaging image sensor substrate 132-2, at least one peripheral circuit for realizing the same function necessary for controlling each of the photoelectric conversion element 132011 and the photoelectric conversion element 132021 is photoelectric A common peripheral circuit (for example, a control circuit 1324, a clock generator 13241, a timing generator 13242, a serial access memory) in which functions realized to correspond to both the conversion element 132011 and the photoelectric conversion element 132021 are integrated A multilayer image sensor 132 formed on a semiconductor substrate (image sensor substrate) of any one of the visible image capturing image sensor substrate 132-1 and the fluorescent image capturing image sensor substrate 132-2 as the serializer 1326). Is configured.

Further, according to the embodiment, the common peripheral circuit may be a clock generator (clock generator 13241 or timing generator 13242) that is a peripheral circuit that generates a reference clock signal based on the supplied master clock MCLK. A storage device (serial access memory 1325) which is a peripheral circuit for storing setting values (parameters) for defining the operation of the stacked image sensor 132, or electricity obtained by photoelectric conversion of the photoelectric conversion element 132011 and the photoelectric conversion element 132021 The layered image sensor 132 is configured as any peripheral circuit of a serializer (serializer 1326) that is a peripheral circuit that outputs a serial imaging signal (serial RAW data) according to a signal (in particular, parallel RAW data) to the outside. And .

Further, according to the embodiment, the interval (pixel pitch) at which the photoelectric conversion element 132011 is formed is light (fluorescent light) that is incident on the visible image pickup image sensor substrate 132-1 and transmits the photoelectric conversion layer 132-11. The stacked image sensor 132 is configured to be equal to or less than an interval at which the influence of diffraction starts to appear (for example, an interval smaller than about 2 um).

Further, according to the embodiment, the fluorescence observation endoscope apparatus (fluorescent observation endoscope apparatus 1) for observing a fluorescent substance (for example, a fluorescent substance consisting of indocyanine green derivative labeled antibody (ICG)) is visible A light source device (light source device 20) capable of irradiating the test object with light including a wavelength band of excitation light (near infrared light) that causes the test object to emit fluorescence by irradiating light and fluorescent material A first photoelectric conversion layer (photoelectric conversion layer 132-11) in which a first photoelectric conversion element (photoelectric conversion element 132011) for photoelectrically converting incident light (visible light and visible light among visible light and fluorescence) is formed; And a first wiring layer (wiring layer 132-12) in which a first wiring (wiring 132012) is formed on the surface opposite to the surface on the light incident side to the photoelectric conversion element 132011 Semiconductor substrate (visible image The image sensor substrate 132-1) for an image and the image sensor substrate 132-1 for visible image pickup were laminated on the side opposite to the light incident side, and the image sensor substrate 132-1 for visible image pickup was transmitted. A second photoelectric conversion layer (photoelectric conversion layer 132-21) in which a second photoelectric conversion element (photoelectric conversion element 132021) for photoelectrically converting light (fluorescence) is formed, and a second wiring (wiring 132022) are formed. Semiconductor substrate (fluorescent image pickup image sensor substrate 132-2) on which a second wiring layer (wiring layer 132-22) is formed, a visible image pickup image sensor substrate 132-1, and a fluorescent image A dielectric multilayer filter (a dielectric multilayer filter 13203 formed on a dielectric multilayer filter layer 132-3) disposed between the imaging image sensor substrate 132-2 and In the photoelectric conversion layer 132-11 is formed between the photoelectric conversion elements 132 011, the refractive index of the light is smaller than the photoelectric conversion layer 132-11 low refractive index material (e.g., silicon dioxide (SiO _2), etc.) are filled And a light transmitting region (a region of an opening for light to be incident) formed at a position corresponding to the photoelectric conversion element 132011 in the wiring layer 132-12. A solid-state imaging device (laminated image sensor 132), and the laminated image sensor 132 is an insertion portion (insertion portion 11) inserted into the inside of a living body (a person to be inspected to which a fluorescent substance consisting of ICG is administered). A fluorescence observation endoscope apparatus (fluorescent observation endoscope apparatus 1) is disposed at the distal end portion (imaging unit 13 provided at the distal end portion of the insertion unit 11).

Further, according to the embodiment, the first photoelectric conversion layer (photoelectric element) in which the first photoelectric conversion element (photoelectric conversion element 132011) for photoelectrically converting the incident light (visible light and visible light among the visible light) is formed. A first wiring layer (wiring layer 132-12) in which a first wiring (wiring 132012) is formed on the conversion layer 132-11) and the surface opposite to the surface on which light is incident on the photoelectric conversion element 132011. And the first semiconductor substrate (visible image imaging image sensor substrate 132-1) on which the light is formed and the surface on the opposite side to the side where light is incident on the visible image imaging image substrate 132-1 Second photoelectric conversion layer (photoelectric conversion layer 132-21) in which a second photoelectric conversion element (photoelectric conversion element 132021) for photoelectrically converting light (fluorescent light) transmitted through the visible image pickup image sensor substrate 132-1 is formed ), And a second semiconductor substrate (fluorescent image pickup image sensor substrate 132-2) on which a second wiring layer (wiring layer 132-22) on which the second wiring (wiring 132202) is formed is formed. A method of manufacturing a solid-state imaging device (laminated image sensor 132), wherein the photoelectric conversion layer 132-11 has a depth of 1 um or more from the surface of the photoelectric conversion layer 132-11 between the photoelectric conversion elements 132011. After forming the recess, the formed recess is filled with a low refractive index material (for example, silicon dioxide (SiO ₂ ) or the like) having a smaller refractive index of light than the photoelectric conversion layer 132-11, and a reflective layer (reflective layer 132014) A manufacturing method of a solid-state imaging device (stacked image sensor 132) including the first step (step 10) of forming

Further, according to the embodiment, at least before Step 10, in the wiring layer 132-12, a light transmission region (a region of an opening for light to be incident) is formed at a position corresponding to the photoelectric conversion element 132011. The back surface electrode (back surface electrode 132016) for extracting the wiring 132012 is formed and planarized on the surface opposite to the light incident side on the step 2 (step 1) and the image sensor substrate 132-1 for visible image capturing. In the third step (step 2) of forming the first bonding surface (bonding surface JS-1) and the dielectric multilayer film filter (surface on the side where light is incident on the fluorescent image pickup image sensor substrate 132-2 The fourth step (step 3) of forming the dielectric multilayer filter 13203) formed in the dielectric multilayer filter layer 132-3 and the surface on the side where light is incident on the dielectric multilayer filter 13203 Body multilayer film each layer (silicon dioxide (SiO ₂₎ thin film layer 132,031 or titanium oxide (TiO ₂₎ film layers 132,032) of the dielectric forming the filter 13203 thick protective film than the thickness of the (protective film 132-4) A fifth step (step 4) of forming, a penetrating electrode (silicon) which penetrates the protective film 132-4 and the dielectric multilayer filter 13203 and draws the wiring 132022 on the surface on the side where light is incident on the protective film 132-4. In the sixth step (steps 5 and 6) of forming the through electrode 132023) and the surface on the light incident side of the protective film 132-4, the formed silicon through electrode 132023 and the protective film 132-4 are together The seventh step (step 7) of forming the second bonding surface (bonding surface JS-2) planarized to the second bonding surface, the bonding surface JS-1 and the bonding surface JS-2 facing each other An eighth step (step 8) of bonding the corresponding back surface electrode 132016 and the silicon through electrode 132023 at the bonding surface JS) and physically and electrically connecting the corresponding back surface electrode 132016 to the silicon through electrode 132023; Configured

As described above, according to the embodiment of the present invention, the solid-state imaging device provided in the fluorescence observation endoscope apparatus includes a visible image capturing image sensor that exposes (detects) light (visible light) in a visible region. And an image sensor for imaging a fluorescence image that exposes (detects) light in the infrared region (near infrared light), with an interlayer filter interposed therebetween. Then, in the embodiment of the present invention, in the light source apparatus provided in the fluorescence observation endoscope apparatus, the white light in the wavelength band of visible light and the white light in the wavelength band of excitation light are irradiated as illumination light to the object to be inspected. . Thereby, in the embodiment of the present invention, in the fluorescence observation endoscope apparatus, a visible image pickup signal in which visible light is exposed, and a derivative-labeled antibody (fluorescent drug: fluorescent substance) such as ICG administered to a subject are excited. Then, it is possible to simultaneously obtain a fluorescence image pickup signal in which fluorescence that is light in the infrared region (near infrared light) that has been fluorescence-emitted is exposed.

Further, in the embodiment of the present invention, any component that can be common to components provided in the visible image capturing image sensor and the fluorescent image capturing image sensor that constitute the solid-state imaging device is one of the image sensors. Have only one. In the embodiment of the present invention, in the solid-state imaging device, the electrode pad (input / output pad) as a terminal for inputting / outputting a signal to / from the outside is shared and disposed only in the visible image pickup image sensor (Form) to reduce the number. Accordingly, in the embodiment of the present invention, the mounting area of the solid-state imaging device can be reduced.

Further, in the embodiment of the present invention, in the visible image pickup image sensor constituting the solid-state imaging device, the reflection layer is formed between the photoelectric conversion elements constituting the respective pixels. More specifically, in the photoelectric conversion layer forming the photoelectric conversion element constituting the pixel of the visible image pickup image sensor, the reflection layer is formed between each photoelectric conversion element. Thus, in the embodiment of the present invention, in the solid-state imaging device, fluorescence that is light in the infrared region (near infrared light) transmitted through the visible image pickup image sensor and incident on the fluorescent image pickup image sensor Even when each pixel is arranged in a narrow interval that diffuses beyond the diffraction limit in the photoelectric conversion layer (when the pixel pitch is narrowed), the near infrared light is efficiently fluorescently reflected by the reflection of the reflective layer. It can be introduced (entered) to the image sensor for image pickup. As a result, in the embodiment of the present invention, in the solid-state imaging device, the decrease in the light amount of the fluorescence is suppressed, and in the fluorescence observation endoscope device, the image quality and resolution of the fluorescence image generated based on the fluorescence imaging signal It is possible to suppress the decline.

As a result, in the embodiment of the present invention, in the solid-state imaging device, the arrangement (formation) of pixels at a pixel pitch at which the influence of diffraction largely appears on the fluorescence transmitted through the visible image pickup image sensor; The miniaturization of the solid-state imaging device can be realized by making the arrangement of the electrode pad (input / output pad) only on the visible image pickup image sensor compatible with each other. By this, in the embodiment of the present invention, in the fluorescence observation endoscope apparatus, the tip portion is curved to perform wide-range observation, and the function to perform imaging of visible light and imaging of fluorescence at the same time. Coexistence can be easily realized.

In the embodiment of the present invention, the image pickup signal output from the solid-state image pickup device (in the embodiment, the laminated image sensor 132) of the present invention corresponds to a signal charge generated by photoelectric conversion of each pixel in the pixel portion. It shows the case of a signal, that is, RAW data. However, the format of the imaging signal output by the solid-state imaging device of the present invention is not limited to the RAW data shown in the embodiment of the present invention. For example, in order to reduce the data amount of the imaging signal transmitted by the laminated image sensor 132 through the imaging signal line 61, each of the R pixel 1320R, the G pixel 1320G, and the B pixel 1320B disposed in the visible image capturing image sensor For example, YC processing may be performed on the pixel signal, and the pixel signal may be converted into a so-called luminance color difference signal such as a YCbCr signal or a YUV signal, and output. In this case, the visible image pickup image sensor converts the pixel signal of the digital value output from the analog / digital conversion unit 1323 into a luminance color difference signal of the digital value, and then converts the serial luminance color difference signal parallel / serial converted by the serializer 1326 Can be output to the outside as a visible image pickup signal. Also, in this case, after the deserializer 32 restores the serial luminance chrominance signal to the original parallel luminance chrominance signal, the external processing unit 30 performs demosaicing processing of the image processing unit 33 for R pixel, G pixel, or B pixel. A configuration may be considered in which respective image data consisting only of pixel signals of any of the pixels in FIG.

In the embodiment of the present invention, the light source device constituting the fluorescence observation endoscope apparatus of the present invention has a configuration in which light of a predetermined wavelength band is emitted by a combination of a white light source and a dichroic mirror. . However, the configuration of the light source device is not limited to the configuration shown in the embodiment of the present invention. For example, instead of a combination of a white light source and a dichroic mirror, a light source that emits light in a predetermined wavelength band is provided, and the light emitted by each light source is collected and emitted by a light irradiation lens. May be In this case, the light source device includes, for example, a white light source that emits light in a wavelength band from blue (B) to red (R) (for example, visible light in a wavelength band of 400 nm to 700 nm); An infrared light source that emits light (for example, near infrared light in a wavelength band of 700 nm to 800 nm) can be considered.

In the embodiment of the present invention, the case where the solid-state imaging device of the present invention is mounted on the fluorescence observation endoscope apparatus of the present invention has been described. However, the apparatus on which the solid-state imaging device of the present invention is mounted is not limited to the fluorescence observation endoscope apparatus shown in the embodiment. For example, the solid-state imaging device of the present invention can be mounted on a microscope device.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments and their modifications. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention.
Also, the present invention is not limited by the above description, and is limited only by the scope of the attached claims.

According to the above embodiment, in the solid-state imaging device configured to stack a plurality of semiconductor substrates on which the photoelectric conversion units are formed and simultaneously image visible light and fluorescence excited by the fluorescent substance, the image quality of the image obtained by imaging fluorescence It is possible to provide a solid-state imaging device capable of achieving downsizing while suppressing a drop in the size, a fluorescence observation endoscope apparatus using the solid-state imaging device, and a method of manufacturing the solid-state imaging device.

1 Fluorescent Observation Endoscope Device 10 Endoscope Section 11 Insertion Part (Insertion Part)
12 operation unit 13 imaging unit (fluorescent observation endoscope apparatus, insertion unit, distal end)
130 Imaging lens 131 Excitation light cut filter 132 Stacked type image sensor (Fluorescent observation endoscope apparatus, solid-state imaging device, first semiconductor substrate, second semiconductor substrate)
1320 pixels (solid-state imaging device, first photoelectric conversion element, second photoelectric conversion element)
1320R R pixel (solid-state imaging device, first semiconductor substrate, first photoelectric conversion element)
1320 G G pixels (solid-state imaging device, first semiconductor substrate, first photoelectric conversion element)
1320B B pixel (solid-state imaging device, first semiconductor substrate, first photoelectric conversion element)
1320IR Fluorescent pixel (Solid-state imaging device, second semiconductor substrate, second photoelectric conversion element)
1321 Pixel area (solid-state imaging device, first photoelectric conversion element, second photoelectric conversion element)
1322 Readout unit (solid-state imaging device, peripheral circuit)
13221 Vertical scanning circuit (solid-state imaging device, peripheral circuit)
13222 Horizontal scanning circuit (solid-state imaging device, peripheral circuit)
1323 Analog / Digital Converter (Solid-state Imaging Device, Peripheral Circuit)
13230 Analog to Digital Converter (Solid-state Imaging Device, Peripheral Circuit)
1324 Control circuit (solid-state imaging device, peripheral circuit, common peripheral circuit)
13241 Clock generator (solid-state imaging device, peripheral circuit, common peripheral circuit)
13242 Timing generator (solid-state imaging device, peripheral circuit, common peripheral circuit)
1325 Serial Access Memory (Solid-state Imaging Device, Peripheral Circuit, Common Peripheral Circuit)
1326 Serializer (Solid-state Imaging Device, Peripheral Circuit, Common Peripheral Circuit)
1327 Vertical signal line (solid-state imaging device, first wiring, second wiring)
1328 Horizontal signal line (solid-state imaging device, first wiring, second wiring)
132-1 Image Sensor Substrate for Visible Image Capture (Solid-state Imaging Device, First Semiconductor Substrate)
132-11 Photoelectric Conversion Layer (Solid-state Imaging Device, First Semiconductor Substrate, First Photoelectric Conversion Layer)
132-12 Wiring Layer (Solid-state Imaging Device, First Semiconductor Substrate, First Wiring Layer)
132011 Photoelectric conversion device (solid-state imaging device, first semiconductor substrate, first photoelectric conversion layer, first photoelectric conversion device)
132012 Wiring (solid-state imaging device, first semiconductor substrate, first wiring layer, first wiring)
132013 Light pipe (solid-state imaging device, first semiconductor substrate, first photoelectric conversion layer, light transmission area, light pipe)
132014 Reflective layer (solid-state imaging device, first semiconductor substrate, first photoelectric conversion layer, reflective layer)
132016 Back electrode (solid-state image sensor, first semiconductor substrate, back electrode)
132015 Silicon penetration electrode (solid-state image sensor, first semiconductor substrate, electrode pad)
132017 Pads for wire bonding (solid-state imaging device, first semiconductor substrate, electrode pad)
132-2 Image Sensor Substrate for Fluorescent Imaging (Solid-state Imaging Device, Second Semiconductor Substrate)
132-21 Photoelectric Conversion Layer (Solid-state Imaging Device, Second Semiconductor Substrate, Second Photoelectric Conversion Layer)
132-22 Wiring Layer (Solid-state Imaging Device, Second Semiconductor Substrate, Second Wiring Layer)
132021 Photoelectric conversion device (solid-state imaging device, second semiconductor substrate, second photoelectric conversion layer, second photoelectric conversion device)
132022 Wiring (solid-state imaging device, second semiconductor substrate, second wiring layer, second wiring)
132023 Silicon penetration electrode (solid-state imaging device, second semiconductor substrate, penetration electrode)
132023a Through Hole 132-3 Dielectric Multilayer Filter Layer (Solid-state Imaging Device, Dielectric Multilayer Filter)
13203 Dielectric Multilayer Filter (Solid-state Imaging Device, Dielectric Multilayer Filter)
132031 Silicon dioxide thin film layer (solid-state imaging device, dielectric multilayer film filter)
132032 Titanium oxide thin film layer (solid-state imaging device, dielectric multilayer film filter)
132-4 Protective film (solid-state image sensor, protective film)
132-5 Support Substrate (Solid-state Imaging Device)
132-6 On-chip color filter layer (solid-state imaging device)
13204 On-chip color filter (solid-state imaging device)
13204R On-chip color filter (solid-state imaging device)
13204G On-chip color filter (solid-state imaging device)
13204B On-chip color filter (solid-state imaging device)
132-7 Microlens Layer (Solid-state Imaging Device)
13205 Micro lens (solid-state imaging device)
1321-1 Pixel part (solid-state imaging device, first photoelectric conversion element)
13221-1 Vertical scanning circuit (solid-state imaging device, first semiconductor substrate, peripheral circuit)
13222-1 Horizontal scanning circuit (solid-state imaging device, first semiconductor substrate, peripheral circuit)
1321-2 Pixel area (solid-state imaging device, second photoelectric conversion element)
13221-2 Vertical scanning circuit (solid-state imaging device, second semiconductor substrate, peripheral circuit)
132222-2 Horizontal scanning circuit (solid-state imaging device, second semiconductor substrate, peripheral circuit)
JS bonding surface (solid-state imaging device, first semiconductor substrate, second semiconductor substrate)
JS-1 Bonding surface (solid-state imaging device, first semiconductor substrate, first bonding surface)
JS-2 Bonding surface (solid-state imaging device, second semiconductor substrate, second bonding surface)
14 Shooting control switch 20 Light source device (Fluorescent observation endoscope device, light source device)
21 Setting unit (Fluorescent observation endoscope device, light source device)
220, 221, 222 White Light Source (Fluorescent Observation Endoscope, Light Source)
231, 232 dichroic mirror (fluorescence observation endoscope apparatus, light source apparatus)
24 Light Irradiation Lens (Fluorescent Observation Endoscope, Light Source)
Reference Signs List 30 external processing unit 31 control unit 32 deserializer 33 image processing unit 34 digital / analog conversion unit 40 color monitor 50 light signal cable 51 light guide 60 electric signal cable 61 imaging signal line 900 abdomen 901 inspection object 930 solid-state imaging device 931 first Substrate 931-1 photoelectric conversion layer 931-2 wiring layer 932 second substrate 932-1 photoelectric conversion layer 932-2 wiring layer 933 bonding layer 934 on-chip color filter layer 935 microlens layer 936 support substrate

Claims

A first photoelectric conversion layer in which a first photoelectric conversion element for photoelectrically converting incident light is formed, and a surface on the side opposite to the surface on which light is incident to the first photoelectric conversion element is a first A first semiconductor substrate on which a first wiring layer in which a wiring is formed is formed;
A second photoelectric conversion element is formed on a surface opposite to the light incident side of the first semiconductor substrate, and a second photoelectric conversion element is formed to photoelectrically convert the light transmitted through the first semiconductor substrate. A second semiconductor substrate on which a conversion layer and a second wiring layer in which a second wiring is formed are formed;
A dielectric multilayer filter disposed between the first semiconductor substrate and the second semiconductor substrate;
A reflective layer formed between the first photoelectric conversion elements in the first photoelectric conversion layer and filled with a low refractive index material having a smaller refractive index of light than the first photoelectric conversion layer When,
A light transmission region formed at a position corresponding to the first photoelectric conversion element in the first wiring layer;
Have
Solid-state imaging device.
The light transmission area is
It has a light pipe formed of a high refractive index material having a light refractive index larger than that of the first wiring layer,
The solid-state imaging device according to claim 1.
An electrode pad formed on the first semiconductor substrate and penetrating the first photoelectric conversion layer to conduct a signal between the first wiring and the outside;
A penetrating electrode which penetrates the dielectric multilayer filter and electrically connects the first wiring and the second wiring;
Have
The solid-state imaging device according to claim 1.
An external signal supplied from any one of a power supply, a ground, and a master clock supplied to the corresponding electrode pad of the first semiconductor substrate is connected to the second wiring through the through electrode, Supply to 2 semiconductor substrates,
The solid-state imaging device according to claim 3.
The first photoelectric conversion element and the second photoelectric conversion element are formed on a semiconductor substrate of at least one of the first semiconductor substrate and the second semiconductor substrate, via the first wiring or the second wiring. A peripheral circuit that controls a conversion element and outputs an electric signal photoelectrically converted by the first photoelectric conversion element and the second photoelectric conversion element to the first wiring or the second wiring.
Have
Among the peripheral circuit formed on the first semiconductor substrate and the peripheral circuit formed on the second semiconductor substrate, each of the first photoelectric conversion element and the second photoelectric conversion element A common function in which at least one peripheral circuit for realizing the same function necessary for control of the functions is integrated so as to correspond to both of the first photoelectric conversion element and the second photoelectric conversion element The peripheral circuit is formed on one of the first semiconductor substrate and the second semiconductor substrate.
The solid-state imaging device according to claim 3 or 4.
The common peripheral circuit is
A clock generator that is the peripheral circuit that generates a reference clock signal based on a supplied master clock; a storage device that is the peripheral circuit that stores a setting value for defining the operation of the solid-state imaging device; The peripheral circuit according to any one of the peripheral circuits according to the first aspect of the present invention, wherein the first photoelectric conversion element and a serial imaging signal corresponding to an electrical signal obtained by photoelectric conversion of the second photoelectric conversion element are output to the outside.
The solid-state imaging device according to claim 5.
The interval at which the first photoelectric conversion element is formed is
It is equal to or less than the interval at which the influence of diffraction starts to appear on the light incident on the first semiconductor substrate and transmitted through the first photoelectric conversion layer
The solid-state imaging device according to claim 1.
A fluorescence observation endoscope apparatus for observing a fluorescent substance, comprising:
A light source device capable of irradiating the test object with light including a wavelength band of visible light and excitation light that causes the test object to emit fluorescence by irradiating the fluorescent material;
A first photoelectric conversion layer in which a first photoelectric conversion element for photoelectrically converting incident light is formed, and a surface on the side opposite to the surface on which light is incident to the first photoelectric conversion element is a first A first semiconductor substrate on which a first wiring layer in which a wiring is formed is formed, and a surface on the side opposite to the side where light is incident on the first semiconductor substrate are laminated, and the first semiconductor substrate A second semiconductor substrate on which a second photoelectric conversion layer in which a second photoelectric conversion element that photoelectrically converts transmitted light is formed, and a second wiring layer in which a second wiring is formed; A dielectric multilayer filter disposed between a first semiconductor substrate and the second semiconductor substrate, and the first photoelectric conversion layer formed between the first photoelectric conversion element, A reflective layer formed by being filled with a low refractive index material having a smaller refractive index of light than the photoelectric conversion layer 1 In the first wiring layer, and a solid-state imaging device having a light transmissive region formed at a position corresponding to the first photoelectric conversion element,
Equipped with
The solid-state imaging device is
Placed at the tip of the insertion part inserted inside the living body,
Fluorescent observation endoscope device.
A first photoelectric conversion layer in which a first photoelectric conversion element for photoelectrically converting incident light is formed, and a surface on the side opposite to the surface on which light is incident to the first photoelectric conversion element is a first A first semiconductor substrate on which a first wiring layer in which a wiring is formed is formed, and a surface on the side opposite to the side where light is incident on the first semiconductor substrate are laminated, and the first semiconductor substrate A second photoelectric conversion layer in which a second photoelectric conversion element that photoelectrically converts transmitted light is formed, and a second semiconductor substrate on which a second wiring layer in which a second wiring is formed is formed; A method of manufacturing a solid-state imaging device,
In the first photoelectric conversion layer, after forming a depression having a depth of 1 um or more from the surface of the first photoelectric conversion layer between the respective first photoelectric conversion elements, A first step of filling a low refractive index material having a smaller refractive index of light than the first photoelectric conversion layer to form a reflective layer;
including,
Method of manufacturing a solid-state imaging device
At least before the first step,
Forming a light transmission region at a position corresponding to the first photoelectric conversion element in the first wiring layer;
A third step of forming a back surface electrode for drawing out the first wiring on a surface opposite to the light incident side of the first semiconductor substrate to form a planarized first bonding surface;
Forming a dielectric multi-layered film filter on a surface on the light incident side of the second semiconductor substrate;
A fifth step of forming a protective film thicker than the thickness of each layer of the dielectric forming the dielectric multilayer filter on the surface on the light incident side of the dielectric multilayer filter;
A sixth step of forming a through electrode which passes through the protective film and the dielectric multilayer filter and draws the second wiring on the surface on the light incident side of the protective film;
A seventh step of forming a second bonding surface in which the formed through electrode and the protective film are planarized on the surface on the light incident side to the protective film;
An eighth step of opposing and bonding the first bonding surface and the second bonding surface, and physically and electrically connecting the corresponding back surface electrode and the through electrode;
including,
The manufacturing method of the solid-state imaging device according to claim 9.