JP5224685B2 - Photoelectric conversion device, manufacturing method thereof, imaging module, and imaging system - Google Patents

Description

  The present invention relates to a photoelectric conversion device, and particularly relates to a light condensing unit and a manufacturing method thereof.

  In photoelectric conversion devices used in digital cameras and camcorders, pixels are miniaturized by downsizing and increasing the number of pixels. Along with this, the area of the light receiving portion of the photoelectric conversion element decreases, and the amount of incident light decreases, resulting in a decrease in sensitivity.

  In order to improve this decrease in sensitivity, an on-chip microlens is formed on the light incident surface of the photoelectric conversion device, and the light is condensed on the light receiving unit to suppress the decrease in sensitivity. Further, in recent years, a structure is known in which an optical waveguide using light reflection is formed between an on-chip microlens and a photoelectric conversion element.

  In general, a method for manufacturing an optical waveguide in such a photoelectric conversion device includes a step of digging a well shape in an insulating layer and embedding the well shape digging portion. A material having a higher refractive index than that of the insulating layer is buried in the buried portion to form a high refractive index region. Then, due to the difference in refractive index between the insulating layer and the high refractive index region, light is reflected at the interface between them, and an optical waveguide that collects light to the photoelectric conversion element is formed.

  However, as the pixels become finer, the aspect ratio of the well-like digging portion becomes higher, and a void may be generated inside the well in the filling step.

  As a means for solving such a problem in the embedding process, a technique as shown in FIG.

  In the photoelectric conversion device shown in FIG. 7, reference numeral 11 denotes a silicon substrate, and reference numeral 15 denotes a photodiode disposed on the substrate 11. Further, a field insulating film disposed between adjacent photodiodes 15 is indicated by 12. Above them, an interlayer insulating film 21 and an SiN film 16 serving as an etching stop layer for stopping the etching when forming the opening are disposed. Further, an optical waveguide portion 22 in which a transparent film is embedded is disposed in the opening of the interlayer insulating film 21. Further, a gate electrode 17, conductive plugs 18A and 18B, and wirings 19A and 19B are arranged, respectively.

  In the photoelectric conversion device shown in FIG. 7, the transparent film is embedded after the openings of different sizes w1 and w2 are formed in the interlayer insulating film 21. Since the size of the opening of the interlayer insulating film 21 is formed so as to increase toward the light incident surface side, it is possible to improve the embedding property that has been a problem described above.

Moreover, there exists a micro light-condensing plate shown in FIG. In FIG. 8, a light receiving element is indicated by 801, a photoresist is indicated by 802, and a high refractive index area is indicated by 803. As a manufacturing method of the light collector, polymethyl methacrylate is applied as a photoresist 802 on the light receiving element 801, patterned, and heated to be deformed into a shape as shown in FIG. As the high refractive index region 803, polyethylene terephthalate is applied and planarized to form a micro light collector.
JP 2003-224249 A JP 06-118208 A

  However, as in the case of the incident light 115 in FIG. 7, in some optical waveguides 22, the sensitivity may be lowered because the optical waveguide 22 may not be incident on the lower optical waveguide portion defined as the opening width w <b> 2 of the interlayer insulating film 21. Arise. The light that does not enter the photodiode 15 passes through the interface between the optical waveguide 22 and the insulating film 21, enters the wiring 19 and the plug 18 portion, and is reflected to cause color mixing and noise. Further, light that enters the upper portion of the wiring 19B instead of the optical waveguide 22 may be reflected by the wiring 19B or the insulating film 21 to cause color mixing or noise.

  Further, when the photoelectric conversion device of FIG. 8 is further miniaturized, the difference between the opening widths w1 and w2 may be increased depending on the arrangement of the wiring layer 19, and the amount of incident light is further reduced. Resulting in.

  Further, in the micro light collector shown in FIG. 8, it is necessary to increase the aspect ratio of the photoresist pattern as shown in FIG. Therefore, formation becomes difficult. Furthermore, Patent Document 2 discloses another method for manufacturing a micro light collector using metal plating or a metal mold, but the process is complicated. In addition, when used in a photoelectric conversion device, there is a concern that defects occur due to metal contamination and noise increases. Further, there is no description of wiring or the like for reading a signal from a photoelectric conversion element or the like. Accordingly, there is room for further study regarding the relationship between the wiring layer, the low refractive index region, and the high refractive index region.

  Accordingly, an object of the present invention is to provide an imaging apparatus having an optical waveguide with good light collection efficiency and a method for manufacturing the same.

Therefore, a method for manufacturing a photoelectric conversion device according to the present invention includes a step of preparing a semiconductor substrate in which a plurality of photoelectric conversion elements are arranged, and a plurality of insulating layers and a plurality of wiring layers are provided on the top, and the photoelectric conversion elements And a step of forming an optical waveguide having a high refractive index material having a higher refractive index than the plurality of insulating layers in the openings. In the manufacturing method, the step of forming the openings in the plurality of insulating layers includes a step of forming a photoresist on the plurality of insulating layers, and a step of patterning the photoresist to form a photoresist pattern. A step of deforming the photoresist pattern by a reflow process, and selectively removing a part of the plurality of insulating layers using the deformed photoresist pattern as a mask. And the step of selectively removing a part of the plurality of insulating layers has a continuous curve in a cross section in a direction perpendicular to the light receiving surface of the photoelectric conversion element, The cross-sectional area parallel to the light-receiving surface of the photoelectric conversion element increases as the distance from the light-receiving surface of the photoelectric conversion element increases, and the rate of increase in the cross-sectional area continuously increases. Part is removed .

  It becomes possible to capture light efficiently and provide an imaging device with improved sensitivity.

  The photoelectric conversion device according to the present invention includes a plurality of photoelectric conversion elements disposed on a semiconductor substrate, and a plurality of wiring layers disposed on the substrate with an interlayer insulating layer interposed therebetween. Further, an opening portion corresponding to the photoelectric conversion element is disposed in the interlayer insulating layer, and the opening portion has a high refractive index region having a higher refractive index than that of the interlayer insulating layer. In such a photoelectric conversion device, the cross-sectional area parallel to the light receiving surface of the photoelectric conversion element in the high refractive index region increases from the light receiving surface of the photoelectric conversion element toward the light incident surface in the high refractive index region. The rate of increase increases continuously.

  According to such an optical waveguide, the area of the cross section parallel to the light receiving surface of the photoelectric conversion element in the high refractive index region is maximized on the light incident surface side of the high refractive index region, thereby increasing the amount of incident light. It becomes possible. Moreover, it becomes possible to reduce the light which enters between optical waveguides, and to suppress color mixing.

  In addition, the cross-sectional area increases continuously, and the rate of increase increases accordingly, so that the cross-sectional shape perpendicular to the light-receiving surface of the photoelectric conversion element of the interlayer insulating layer (side wall of the optical waveguide) is continuous. Has a curve. Since there is no flat portion as shown in FIG. 7 on the light incident surface side of the optical waveguide having such a side wall, it becomes easier to reflect incident light to the light receiving surface of the photoelectric conversion element. Further, even when oblique light is incident, the light can be further reflected to the light receiving surface of the photoelectric conversion element. Therefore, it is possible to suppress a decrease in sensitivity particularly in a lens having a low F number called a bright lens with a lot of oblique light, and it is also possible to suppress a decrease in sensitivity due to a decrease in the amount of light at the pixel peripheral portion.

  Further, since this shape is such that the opening of the interlayer insulating layer becomes smaller on the photoelectric conversion element side, the degree of freedom in designing the wiring layer formed between the interlayer insulating layers is improved. When designing the opening, it is preferable to reflect the design of the wiring layer arranged closest to the photoelectric conversion element. With this shape, the photoelectric conversion device is further miniaturized, and the wiring layer can be designed without difficulty, and at the same time, it is possible to have a wide opening for incident light. Here, the wiring layer is a conductive layer such as a wiring, but may be a pattern layer having a light shielding function.

  Moreover, the manufacturing method of this invention has the process of forming a some wiring layer through an interlayer insulation layer on the semiconductor substrate with which the some photoelectric conversion element was distribute | arranged. A step of forming an opening corresponding to the photoelectric conversion element in the interlayer insulating layer; and a step of embedding a high refractive index material having a higher refractive index than the interlayer insulating layer in the opening to form an optical waveguide. Yes. Further, the step of forming the opening includes a step of forming a photoresist on the interlayer insulating layer, and a step of patterning the photoresist in accordance with the position of the opening to form a photoresist pattern. And a step of deforming the photoresist pattern by a reflow process, and a step of selectively removing a part of the interlayer insulating layer using the deformed photoresist pattern as a mask to form an opening. .

  According to this method, compared with the manufacturing method described in Patent Document 2, it is easy to form a desired shape and can be formed with high accuracy. Even when the size is further reduced and the aspect ratio of the shape is increased, the desired shape can be accurately formed by controlling the etching conditions. Accordingly, there is a shape in which the area of the cross section parallel to the light receiving surface of the photoelectric conversion element in the high refractive index region described above continuously increases from the light receiving surface of the photoelectric conversion element toward the light incident surface of the insulating layer. It can also be manufactured with high accuracy.

  Here, by forming a layer made of a material having a smaller etching selectivity than the interlayer insulating layer over at least a part of the photoelectric conversion element, damage to the etching process that the photoelectric conversion element receives can be reduced. It becomes possible.

  Here, a semiconductor substrate which is a material substrate is expressed as a “substrate”, but includes a case where the following material substrate is processed. For example, a member in which one or a plurality of semiconductor regions and the like are formed, a member in the middle of a series of manufacturing steps, or a member that has undergone a series of manufacturing steps can also be referred to as a substrate.

  Further, “on the semiconductor substrate” represents the main surface on which the pixels of the semiconductor substrate are formed. The direction from the main surface of the semiconductor substrate to the inside of the substrate is the downward direction, and the opposite is the upward direction.

(Pixel circuit configuration)
FIG. 11 shows a MOS photoelectric conversion device as an example of a circuit configuration of a pixel in the photoelectric conversion device. Each pixel is indicated at 1110.

  The pixel 1110 includes a photodiode 1100 that is a photoelectric conversion element, a transfer transistor 1101, a reset transistor 1102, an amplification transistor 1103, and a selection transistor 1104. Here, the power supply line is indicated by Vcc and the output line is indicated by 1105.

  The photodiode 1100 has an anode connected to the ground line and a cathode connected to the source of the transfer transistor 1101. In addition, the source of the transfer transistor can also serve as the cathode of the photodiode.

  The drain of the transfer transistor 1101 forms a floating diffusion (hereinafter referred to as FD) which is a transfer region, and the gate thereof is connected to the transfer signal line. Further, the reset transistor 1102 has a drain connected to the power supply line Vcc, a source constituting the FD, and a gate connected to the reset signal line.

  The amplification transistor 1103 has a drain connected to the power supply line Vcc, a source connected to the drain of the selection transistor 1104, and a gate connected to the FD. The selection transistor 1104 has its drain connected to the source of the amplification transistor 1103, its source connected to the output line 1105, and its gate connected to a vertical selection line driven by a vertical selection circuit (not shown).

  The circuit configuration shown here can be applied to all the embodiments of the present invention, but can be applied to, for example, a configuration without a transfer transistor or other circuit configurations in which a plurality of pixels share a transistor. As the photoelectric conversion element, a photodiode, a phototransistor, or the like can be used. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic cross-sectional view of the MOS photoelectric conversion device described above in the direction perpendicular to the semiconductor substrate.

  In FIG. 1, 101 is a semiconductor substrate, and 102 is a photoelectric conversion element disposed on the semiconductor substrate. Reference numeral 103 denotes an element isolation region disposed between two adjacent photoelectric conversion elements 102. Reference numeral 120 denotes an etching stop layer for stopping etching when forming the opening. The etching stop layer 120 may be disposed at least on the photoelectric conversion element, but in the present embodiment, the etching stop layer 120 is disposed on the entire surface of the semiconductor substrate 101. Reference numeral 104 denotes a first insulating layer which is an interlayer insulating layer. In the case of a CMOS type photoelectric conversion device, a gate electrode is formed on a semiconductor substrate, but is omitted here.

  A wiring layer 105 is provided on the first insulating layer 104. Reference numeral 106 denotes a second insulating layer which is an interlayer insulating layer, and is arranged so as to cover the first pattern layer 105. A wiring layer 107 is disposed on the second insulating layer. Reference numeral 108 denotes a protective layer, which is disposed on the second wiring layer 107.

  Furthermore, a 110 high refractive index region having a higher refractive index than that is provided in the opening of the interlayer insulating layer made up of the first and second insulating layers 104 and 106 on the photoelectric conversion element 102. An optical waveguide that reflects light is formed at the interface between the high refractive index region 110 and the interlayer insulating layer. Here, when a material having a refractive index equivalent to that of the interlayer insulating layer is used for the protective layer 108, it is possible to form an optical waveguide that reflects light at the interface between the protective layer 108 and the high refractive index region 110. It becomes.

  An intermediate layer 111 is provided on the protective layer 108, and a color filter layer 112, a planarizing layer 113, and a microlens 114 are provided in this order. Here, the intermediate layer 111 is a planarization layer, an antireflection film, a light shielding film, or the like.

  Next, schematic cross-sectional views of the MOS type photoelectric conversion device shown in FIG. 1 in the direction parallel to and perpendicular to the semiconductor substrate are shown in FIGS. 2A and 2B, respectively.

  FIG. 2A is a schematic projection of a plane parallel to the semiconductor substrate of the MOS photoelectric conversion device. A region of the photoelectric conversion element 102 is indicated by a dotted line, a first pattern is indicated by 105, and a second pattern is indicated by 107. The second pattern 107 has a part omitted so that the layer below it is easy to understand. Further, a high refractive index region is indicated at 110. Further, a wiring layer may be provided between 105 and 107 as shown in FIG. This wiring layer does not appear in FIG. A schematic cross-sectional view taken along the line ab in FIG. 2A is shown in FIG. The color filter layer 112 and the like shown in FIG. 1 are omitted.

  The cross section parallel to the light receiving surface of the photoelectric conversion element in the high refractive index region 110 shown in FIG. 2A has a shape that continuously increases from the photoelectric conversion element 102 toward the light incident surface of the interlayer insulating layer. With this shape, the amount of incident light can be increased.

  Further, the cross section in the direction perpendicular to the light receiving surface of the photoelectric conversion element 102 in the opening of the interlayer insulating layer shown in FIG. 2B, that is, the side wall of the high refractive index region 110 is a continuous curve as shown in the figure. have. Compared to the shape as shown in FIG. 7, oblique incident light can be reflected to the light receiving surface of the photoelectric conversion element, and the light collection efficiency is improved.

  Further, with such a shape, for example, as shown in FIG. 1, the first wiring layer 105 can have a higher wiring density than the second wiring layer 107. That is, in designing the wiring layer, particularly the first wiring layer 105 formed on the photoelectric conversion element 102 side, the degree of freedom is improved and it is easy to cope with further miniaturization.

  Next, the manufacturing method of the photoelectric conversion apparatus of this embodiment is demonstrated using FIGS. An element isolation region 103 is formed by a LOCOS method or the like on a semiconductor substrate 101 made of a silicon wafer or the like shown in FIG. Then, a photoresist pattern is formed on the semiconductor substrate 101, ion implantation and heat treatment are performed, and the photoelectric conversion element 102 is formed.

  Next, an etching stop layer 120 is formed on the semiconductor substrate 101 by CVD or the like, and further, a first insulating layer 104 made of SiO or a material mainly containing it is formed. Here, if the surface of the first insulating layer 104 is planarized by CMP or the like, the patterning accuracy in the next process can be improved.

  A first wiring layer is formed by forming a metal layer made of Al, Mo, W, Ta, Ti, Cu, or an alloy containing these as a main component on the first insulating layer 104 by sputtering and patterning. 105 is formed.

  Next, a second insulating layer 106 made of SiO or a material containing it as a main component is formed on the first insulating layer 104 and the first wiring layer 105. Then, a second wiring layer 107 is formed on the second insulating layer 106 by a method similar to that for the first wiring layer.

  Here, the first and second wiring layers 105 and 107 function as wirings used for transmission of electrical signals from the photoelectric conversion element 102, and light to be incident on a certain photoelectric conversion element 102 is converted into other photoelectric conversions. It also functions as a light shielding portion that prevents the light from entering the element 102.

  Next, as shown in FIG. 3B, a protective layer 108 made of SiO, SiN, SiON or the like is formed. 3 (b), 4 (c), and 4 (d), the protective layer 108 has a concavo-convex portion, but emphasizes that it reflects the shape of the second wiring layer. It is only shown and the protective layer 108 may be flat.

  As shown in FIG. 4C, an etching mask for forming an opening directly above the photoelectric conversion element 102 is formed on the protective layer 108. First, a photoresist pattern 109 is formed on the protective layer 108. The photoresist pattern 109 matches the shape of the convex portion of the protective layer 108 in the figure, but as described above, this is schematically shown and is limited to this shape and arrangement. It is not something that can be done. What is necessary is just to arrange | position suitably so as to correspond to the photoelectric conversion element 102. FIG. Thereafter, heat treatment is performed so that the photoresist pattern 109 has a shape as shown in FIG. By reflowing by this heat treatment, the photoresist pattern 109 has a shape such as a part of a sphere or a shape having a convex rounded shape. Next, as shown in FIG. 5E, etching proceeds toward the photoelectric conversion element 102 using the reflowed photoresist pattern 109 as an etching mask. Then, etching is stopped at the etching stop layer 120, and the opening of the interlayer insulating layer of this embodiment, that is, the shape of the waveguide is obtained. This etching condition is such that the etching selection ratio of the etching stop layer 120 is smaller than that of the interlayer insulating layer. That is, the etching rate of the etching stop layer 120 is sufficiently lower than the etching rates of the first and second insulating layers 104 and 106 that are interlayer insulating layers.

  At this time, the shape of the opening of the formed interlayer insulating layer can be controlled by the shape of the reflowed photoresist pattern 109 used as an etching mask, the etching conditions, and the etching selectivity between the interlayer insulating layer and the resist. Is possible. Therefore, the opening portion having a high aspect ratio can be etched with good control, and a desired shape can be obtained. In addition, the area of the opening closest to the photoelectric conversion element 102, that is, the area of the bottom of the optical waveguide is desirably smaller than the area of the light receiving part of the photoelectric conversion element 102. With this configuration, the incident efficiency of light reflected by the optical waveguide is improved.

Next, the photoresist pattern 109 is removed, and a high refractive index material is buried in the opening of the interlayer insulating layer by CVD to form a high refractive index region 110. (See FIG. 5 (f) to FIG. 6 (g))
As shown in FIG. 6H, the high refractive index region 110 is planarized by etch back using plasma etching or CMP. By performing planarization, the shape of the next process can be controlled. Here, since the dark current and the pixel defect may increase due to the plasma damage to the photoelectric conversion element 102, the planarization is preferably performed by the CMP without the plasma damage.

  In the present embodiment, the end point of planarization is the protective layer 108, but it is also possible to stop within the high refractive index region 110 before reaching the protective layer 108. In this case, the step of the protective layer 108 shown in FIG. 3B can be omitted, and the high refractive index region 110 can also serve as the protective layer.

  Finally, as shown in FIG. 6I, an intermediate layer 111 made of resin or the like, a color filter layer 112, and a planarization layer 113 are formed in this order to form a microlens 114.

  The optical waveguide having the shape of this embodiment has a wide opening and improves light collection efficiency. In addition, it is possible to reduce light incident between the optical waveguides from being reflected by the protective layer 108, the wiring layer, the color filter layer 112, and the like and leaking into adjacent pixels.

  Furthermore, since this shape is a shape in which the cross-sectional area of the high refractive index region parallel to the light receiving surface of the photoelectric conversion element is reduced on the photoelectric conversion element side, the degree of freedom in designing the wiring layer formed in the interlayer insulating layer Will improve. In particular, the degree of freedom of the wiring layer formed on the photoelectric conversion element side can be improved. Therefore, even when the photoelectric conversion device is miniaturized and the opening on the photoelectric conversion element side becomes narrow due to the formation of the wiring layer, it is possible to have a wide opening for incident light, and the light collection efficiency is improved. To do.

(Second Embodiment)
FIG. 12 is a schematic cross-sectional view of the photoelectric conversion element portion of the photoelectric conversion device. The difference from the first embodiment is the configuration of the protective layer. In the present embodiment, a third insulating layer 116 is disposed so as to cover the second wiring layer 107, and a protective layer 117 having, for example, SiN is disposed thereon. The third insulating layer 116 has, for example, a SiO layer, and the protective layer 117 has, for example, a SiN layer. At this time, since the difference in refractive index at the interface between the high refractive index region 110 and the third insulating layer 116 is large, reflection of light on the upper side of the second wiring layer 107 is increased, and the light collection efficiency is improved. . Furthermore, the protective layer 117 is formed flat by the configuration in which the protective layer 117 is disposed on the third insulating layer 116 and the high refractive index region 110. In addition, since the protective layer 117 is flat, the hydrogen termination effect on the semiconductor substrate formed by the SiN layer of the protective layer 117 can be obtained uniformly.

(Application to imaging module)
FIG. 9 is a configuration diagram illustrating an example when the photoelectric conversion device described in the first and second embodiments of the present invention is applied to an imaging module used in a portable device.

  There is a cover member 904 for installing and sealing the photoelectric conversion device 900 on a substrate 907 such as ceramic. This substrate 907 is electrically connected to the photoelectric conversion device 900. On the photoelectric conversion device 900, an optical portion 905 for capturing light and an optical low-pass filter 906 are installed. Further, the imaging lens 902 and the lens barrel member 901 that fixes the imaging lens 902 cover the cover member 904 and are well sealed with the substrate 907.

  In this application, not only the photoelectric conversion device of the present invention but also an imaging signal processing circuit, an A / D converter (analog / digital converter), and a module control unit may be mounted on the substrate 907. Further, they may be formed on the same semiconductor substrate (FIG. 1, 101) as the photoelectric conversion device by the same process.

(Application to imaging system)
FIG. 10 is a block diagram when the photoelectric conversion device described in the first and second embodiments of the present invention is applied to a digital camera which is an example of an imaging system. Other imaging systems include camcorders.

  As a configuration for taking light into the solid-state imaging device 1004 which is a photoelectric conversion device, there are a shutter 1001, an imaging lens 1002, and an aperture 1003. The shutter 1001 controls exposure to the solid-state image sensor 1004, and incident light is imaged on the solid-state image sensor 1004 by the imaging lens 1002. At this time, the amount of light is controlled by the diaphragm 1003.

  A signal output from the solid-state imaging device 1004 in accordance with the captured light is processed by the imaging signal processing circuit 1005 and converted from an analog signal to a digital signal by the A / D converter 1006. The output digital signal is further processed by the signal processing unit 1007 to generate captured image data. The captured image data can be stored in the memory 1010 mounted on the digital camera or transmitted to an external device such as a computer or a printer through the external I / F unit 1013 according to the setting of the operation mode of the user. The captured image data can also be recorded on a recording medium 1012 that can be attached to and detached from the digital camera through the recording medium control I / F unit 1011.

  The solid-state imaging device 1004, the imaging signal processing circuit 1005, the A / D converter 1006, and the signal processing unit 1007 are controlled by a timing generation unit 1008, and the entire system is controlled by an overall control unit / arithmetic unit 1009. In addition, these systems can be formed on the same semiconductor substrate (FIG. 1, 101) as the solid-state imaging device 1004 by the same process.

  As described above, a wide width on the light incident surface side of the optical waveguide can be secured, so that the light incident on the microlens can be efficiently collected on the photoelectric conversion element. In addition, since the width of the optical waveguide on the photoelectric conversion element side can be reduced, the degree of freedom in pattern design is improved. This is effective for further miniaturization. In addition, since obliquely incident light can be efficiently focused on the photoelectric conversion element, even a lens with a low F value called a so-called bright lens has a small decrease in sensitivity, and a decrease in sensitivity due to a decrease in the amount of light at the periphery of the pixel is also suppressed. it can.

  By the manufacturing method using the reflowed photoresist as an etching mask, it becomes easy to form an optical waveguide having a shape with high light collection efficiency. Further, the shape can be formed with better control.

  As described above, according to the present invention, a photoelectric conversion device with improved sensitivity can be manufactured and provided. Further, the present invention is not limited to the embodiment shown in the embodiments, and can be applied to a photoelectric conversion device including a number of wiring layers and insulating layers.

It is sectional drawing of the photoelectric conversion apparatus of 1st Embodiment. It is the top view (A) and sectional drawing (B) of the photoelectric conversion apparatus of 1st Embodiment. It is a manufacturing process of the photoelectric conversion apparatus of 1st Embodiment. It is a manufacturing process of the photoelectric conversion apparatus of 1st Embodiment. It is a manufacturing process of the photoelectric conversion apparatus of 1st Embodiment. It is a manufacturing process of the photoelectric conversion apparatus of 1st Embodiment. It is sectional drawing of a photoelectric conversion apparatus. It is sectional drawing of a micro light-condensing plate. It is a block diagram of an imaging module of an example which applied the photoelectric conversion apparatus. It is a block diagram which shows the structure of an example digital camera which applied the photoelectric conversion apparatus. It is an example of the equivalent circuit of a photoelectric conversion apparatus. It is sectional drawing of the photoelectric conversion apparatus of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Semiconductor substrate 102 Photoelectric conversion element 103 Element isolation region 104 1st insulating layer 105 1st wiring layer 106 2nd insulating layer 107 2nd wiring layer 108 Protective layer 109 Photoresist 110 High refractive index area | region 111 Intermediate layer 112 Color filter layer 113 Planarizing layer 114 Micro lens 115 Incident light 120 Etching stop layer

Claims (8)

Preparing a semiconductor substrate on which a plurality of photoelectric conversion elements are arranged and having a plurality of insulating layers and a plurality of wiring layers provided thereon; and forming openings corresponding to the photoelectric conversion elements in the plurality of insulating layers And a method of manufacturing a photoelectric conversion device including a step of forming an optical waveguide having a high refractive index material having a higher refractive index than the plurality of insulating layers in the opening,
The step of forming the openings in the plurality of insulating layers includes a step of forming a photoresist on the plurality of insulating layers, a step of patterning the photoresist to form a photoresist pattern, and the photoresist pattern. And a step of selectively removing a part of the plurality of insulating layers using the deformed photoresist pattern as a mask.
In the step of selectively removing a part of the plurality of insulating layers, the opening has a continuous curve in a cross section in a direction perpendicular to the light receiving surface of the photoelectric conversion element. A portion of the plurality of insulating layers is removed so that a cross-sectional area parallel to the surface increases as the distance from the light receiving surface of the photoelectric conversion element increases, and the rate of increase in the cross-sectional area continuously increases. A method for manufacturing a photoelectric conversion device.   The photoelectric conversion device according to claim 1, wherein the step of forming the optical waveguide includes a step of forming a member made of a high refractive index material in the opening and a step of flattening the member made of the high refractive index material. Manufacturing method.   The method for manufacturing a photoelectric conversion device according to claim 2, wherein the flattening step is performed by etching or CMP. Forming a protective layer covering the uppermost wiring layer of the plurality of wiring layers;
The method for manufacturing a photoelectric conversion device according to claim 2, wherein an end point of the flattening step is the protective layer. Forming a protective layer covering the uppermost wiring layer of the plurality of wiring layers;
The method for manufacturing a photoelectric conversion device according to claim 2 or 3, wherein an end point of the flattening step is in a member made of the high refractive index material before reaching the protective layer.   4. The method of manufacturing a semiconductor device according to claim 1, further comprising a step of forming a protective layer that covers an uppermost wiring layer among the plurality of wiring layers. 5.   The method for manufacturing a semiconductor device according to claim 4, wherein the protective layer is made of silicon nitride. In the step of preparing the semiconductor substrate, the method includes a step of forming an etching stop layer on the plurality of photoelectric conversion elements,
The method for manufacturing a semiconductor device according to claim 1, wherein in the step of selectively removing a part of the plurality of insulating layers, a part of the insulating layer is etched up to the etching stop layer.

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