WO2013035258A1 - Solid-state image capture device and method of manufacturing same - Google Patents

Solid-state image capture device and method of manufacturing same Download PDF

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Publication number
WO2013035258A1
WO2013035258A1 PCT/JP2012/005319 JP2012005319W WO2013035258A1 WO 2013035258 A1 WO2013035258 A1 WO 2013035258A1 JP 2012005319 W JP2012005319 W JP 2012005319W WO 2013035258 A1 WO2013035258 A1 WO 2013035258A1
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Prior art keywords
solid
imaging device
state imaging
forming
film
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PCT/JP2012/005319
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French (fr)
Japanese (ja)
Inventor
敦夫 和田
鈴木　政勝
明 大平
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パナソニック株式会社
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Publication of WO2013035258A1 publication Critical patent/WO2013035258A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0232—Optical elements or arrangements associated with the device
    • H01L31/02327—Optical elements or arrangements associated with the device the optical elements being integrated or being directly associated to the device, e.g. back reflectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/1462—Coatings
    • H01L27/14621—Colour filter arrangements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14625—Optical elements or arrangements associated with the device
    • H01L27/14627—Microlenses
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14625—Optical elements or arrangements associated with the device
    • H01L27/14629—Reflectors

Definitions

  • the present invention relates to a solid-state imaging device including an optical waveguide and a method for manufacturing the same.
  • a solid-state imaging device represented by a CCD (Charge Coupled Device) and a MOS (Metal Oxide Semiconductor) image sensor is a semiconductor device using an electrical signal obtained by photoelectrically converting incident light by a photodiode of each pixel.
  • This solid-state imaging device is mounted on a video camera, a digital still camera, or the like.
  • FIG. 8 is a cross-sectional view showing a configuration of the solid-state imaging device 300 described in Patent Document 1.
  • a solid-state imaging device 300 illustrated in FIG. 8 includes an insulating layer 103 that is formed over a semiconductor substrate 101 and includes wiring therein.
  • An optical waveguide forming hole is formed in the upper portion of the light receiving portion 102 of the insulating layer 103, and an optical waveguide 105a is formed by embedding a translucent material 112 in the optical waveguide forming hole.
  • a microlens 109 is provided above the optical waveguide 105a. The focal point of the micro lens 109 is set in the optical waveguide 105 a and in the vicinity of the surface of the light receiving unit 102.
  • the incident light is collected in the optical waveguide 105a. Further, by configuring the optical waveguide 105a with an insulating layer having a refractive index higher than that of the insulating layer 103 around the optical waveguide 105a, light incident obliquely to the optical waveguide 105a is not scattered and the optical waveguide 105a Reflected by the side wall. As a result, light can be efficiently propagated onto the light receiving unit 102.
  • the microlenses of adjacent pixels approach or come into contact with each other, and a translucent material is provided continuously with the adjacent pixels. For this reason, color mixing occurs when light incident at a low angle propagates through the light-transmitting material and the incident light leaks to adjacent pixels.
  • an object of the present invention is to provide a solid-state imaging device capable of suppressing a decrease in sensitivity characteristics and suppressing the occurrence of color mixing.
  • a solid-state imaging device includes a semiconductor substrate, a plurality of photoelectric conversion units formed in a matrix on the semiconductor substrate, and an interlayer formed on the semiconductor substrate.
  • Each of the plurality of optical waveguides includes an embedded portion embedded in the interlayer insulating film, and a protruding portion formed to protrude from the interlayer insulating film, the protruding portion including an upper surface of the embedded portion, and When viewed in plan, the periphery of the buried portion in the interlayer insulating film is covered.
  • the solid-state imaging device can suppress a decrease in sensitivity characteristics and suppress the occurrence of color mixing.
  • the solid-state imaging device may further include a flattening film that separates the adjacent protrusions.
  • the protruding portion may have a shape that fits in a region surrounded by the partition corresponding to one pixel cell when viewed in plan.
  • the embedded portion and the protruding portion may be formed of the same material.
  • the upper surface of the projecting portion may be exposed from the planarizing film.
  • the imaging region in which the plurality of photoelectric conversion units are formed includes a central part and a peripheral part located outside the central part, and is viewed in plan in a central pixel disposed in the central part.
  • the center position of the embedding part and the center position of the projecting part coincide with each other, and the center position of the projecting part when viewed in plan is the peripheral pixel arranged in the perimeter part. You may be in the center direction side of the above-mentioned imaging field to the center position.
  • the solid-state imaging device further includes a microlens formed above each of the plurality of color filters, and in the peripheral pixels, the center position of the partition wall when viewed in plan, and the center position of the microlens May be on the center direction side of the imaging region with respect to the center position of the embedded portion.
  • a first shift amount between the center position of the embedded portion and the center position of the protruding portion, and a second shift amount between the center position of the embedded portion and the center position of the partition wall may satisfy a relationship of first deviation amount ⁇ second deviation amount ⁇ third deviation amount.
  • the first displacement amount is smaller than the radius of the upper end portion of the embedded portion
  • the third displacement amount is an end portion of the projecting portion on the central direction side of the imaging region and the photoelectric conversion portion. It may be smaller than the planar distance from the center position.
  • the cross-sectional shape of the protruding portion may be a square shape, a trapezoidal shape, or a lens shape.
  • planar shape of the protruding portion may be a square, a rectangle, a polygon, a circle, or an ellipse.
  • the refractive index of the optical waveguide may be larger than the refractive index of the planarization film, and the refractive index of the color filter may be larger than the refractive index of the partition wall.
  • the solid-state imaging device may further include a wiring formed in the interlayer insulating film, and a part of the protruding portion may overlap the wiring when viewed in plan.
  • a method for manufacturing a solid-state imaging device includes a step of forming a plurality of photoelectric conversion units in a matrix on a semiconductor substrate, a step of forming an interlayer insulating film on the semiconductor substrate, Forming a hole above each of the plurality of photoelectric conversion portions of the interlayer insulating film, the embedded portion embedded in the hole, an upper surface of the embedded portion, and the embedded in the interlayer insulating film when viewed in plan
  • the method for manufacturing a solid-state imaging device can manufacture a solid-state imaging device that can suppress the occurrence of color mixing and can improve sensitivity characteristics.
  • the step of forming the optical waveguide includes a step of forming an optical waveguide formation film above the interlayer insulating film, a step of forming a resist pattern above the hole on the optical waveguide formation film, and the resist Forming a projection larger than the opening of the hole when viewed in plan using the pattern as an etching mask.
  • the step of forming the planarization film includes the step of forming a planarization film formation film that covers the interlayer insulating film and the optical waveguide, and the planarization using CMP (Chemical Mechanical Polishing) or etch back. Exposing the upper surface of the protruding portion from the film forming film.
  • CMP Chemical Mechanical Polishing
  • the step of forming the partition wall includes a step of forming a partition wall formation film on the planarizing film, and etching the partition wall formation film to form the partition wall that surrounds the photoelectric conversion unit when viewed in plan.
  • the color filter may be formed by embedding the color filter forming material in a region surrounded by the partition wall.
  • the present invention can be realized as a semiconductor integrated circuit (LSI) that realizes part or all of the functions of such a solid-state imaging device, or as an imaging device (camera) including such a solid-state imaging device. it can.
  • LSI semiconductor integrated circuit
  • imaging device camera
  • the present invention can provide a solid-state imaging device capable of suppressing a decrease in sensitivity characteristics and suppressing the occurrence of color mixing.
  • FIG. 1A is a cross-sectional view of the solid-state imaging device according to the first embodiment of the present invention.
  • FIG. 1B is a cross-sectional view of the solid-state imaging device according to the first embodiment of the present invention.
  • FIG. 2 is a plan view of the solid-state imaging device according to the first embodiment of the present invention.
  • FIG. 3 is a plan view of the solid-state imaging device according to the first embodiment of the present invention.
  • FIG. 4A is a sectional view of the solid-state imaging device according to the first embodiment of the present invention in the manufacturing process.
  • FIG. 4B is a cross-sectional view in the process of manufacturing the solid-state imaging device according to the first embodiment of the present invention.
  • FIG. 4C is a cross-sectional view in the process of manufacturing the solid-state imaging device according to the first embodiment of the present invention.
  • FIG. 4D is a cross-sectional view of the solid-state imaging device according to the first embodiment of the present invention in the manufacturing process.
  • FIG. 5A is a cross-sectional view in the process of manufacturing the solid-state imaging device according to the first embodiment of the present invention.
  • FIG. 5B is a cross-sectional view of the solid-state imaging device according to the first embodiment of the present invention in the manufacturing process.
  • FIG. 5C is a cross-sectional view in the process of manufacturing the solid-state imaging device according to the first embodiment of the present invention.
  • FIG. 5D is a cross-sectional view of the solid-state imaging device according to the first embodiment of the present invention in the manufacturing process.
  • FIG. 6A is a cross-sectional view in the process of manufacturing the solid-state imaging device according to the first embodiment of the present invention.
  • FIG. 6B is a cross-sectional view of the solid-state imaging device according to the first embodiment of the present invention in the manufacturing process.
  • FIG. 6C is a cross-sectional view in the process of manufacturing the solid-state imaging device according to the first embodiment of the present invention.
  • FIG. 6D is a cross-sectional view of the solid-state imaging device according to the first embodiment of the present invention in the manufacturing process.
  • FIG. 7 is a cross-sectional view of a solid-state imaging device according to the second embodiment of the present invention.
  • FIG. 8 is a cross-sectional view of a conventional solid-state imaging device.
  • FIG. 1A and 1B are cross-sectional views showing the configuration of the solid-state imaging device 100 according to the first embodiment of the present invention.
  • FIG. 1A is a cross-sectional view of a pixel cell (hereinafter referred to as a central pixel) disposed in the central portion of an imaging region (pixel array).
  • FIG. 1B is a cross-sectional view of a pixel cell (peripheral pixel) arranged in a peripheral portion away from the center of the imaging region.
  • the peripheral part is an area located outside the imaging area from the central part.
  • a solid-state imaging device 100 includes a semiconductor substrate 10, a plurality of photoelectric conversion units 11 formed in a matrix on the semiconductor substrate 10, and a semiconductor.
  • Interlayer insulating film 20 formed on substrate 10, optical waveguide 30 formed for each pixel cell on interlayer insulating film 20, and planarization film 40 formed around optical waveguide 30 on interlayer insulating film 20.
  • a color filter 60 formed on the optical waveguide 30 and the flattening film 40, in which a pigment is dispersed in an organic material, a partition wall 50 made of an insulating film that separates adjacent color filters 60, and the color filter 60.
  • a microlens 70 that condenses incident light on the photoelectric conversion unit 11.
  • the photoelectric conversion unit 11 is, for example, a photodiode, and photoelectrically converts incident light into an electrical signal.
  • the interlayer insulating film 20 is a stacked body in which a plurality of films are stacked.
  • Each film is made of a material having a first refractive index lower than a second refractive index of a material constituting the optical waveguide 30 described later.
  • the first refractive index material include silicon oxide such as BPSG (Boron Phosphorous Silicate Glass) and NSG (None-doped Silicate Glass) having a refractive index of 1.45, and insulator materials such as silicon carbide. Can be mentioned.
  • the interlayer insulating film 20 has a hole 23 in a portion of the surface region that is above the photoelectric conversion unit 11.
  • a plurality of wiring layers 21 (a wiring layer 21a and a wiring layer 21b) mainly made of metal such as Cu are formed.
  • These wiring layers 21 are disposed in the upper part of the interlayer insulating film 20 between the adjacent photoelectric conversion units 11 so as not to prevent light from entering the photoelectric conversion units 11.
  • the film thickness of the interlayer insulating film 20 is about 0.5 ⁇ m.
  • the diameter of the hole 23 is substantially equal to the width of the photoelectric conversion unit 11 and is, for example, about 0.9 ⁇ m.
  • the optical waveguide 30 is formed above each of the plurality of photoelectric conversion units 11.
  • the optical waveguide 30 is translucent and is made of a material having a second refractive index higher than a first refractive index of the interlayer insulating film 20 and a third refractive index of a material constituting the planarizing film 40 described later.
  • the second refractive index material include an organic material containing TiO such as TiO-dispersed polyimide having a refractive index of 1.8 to 1.9, or silicon nitride having a refractive index of 2.0.
  • the optical waveguide 30 includes an embedded portion 30c embedded in the hole 23 of the interlayer insulating film 20, and a protruding portion 30b that is a portion formed above the interlayer insulating film 20 (that is, a portion protruding from the hole 23). including.
  • the protruding portion 30b is formed to protrude from the interlayer insulating film 20, and covers the upper surface of the embedded portion 30c.
  • the protruding portion 30b rides on the upper surface of the interlayer insulating film 20 around the buried portion 30c and covers the interlayer insulating film 20 around the buried portion 30c. That is, the optical waveguide 30 is configured to completely cover the corner portion of the upper end portion of the hole 23 in the interlayer insulating film 20. Further, the upper surface of the protruding portion 30 b is exposed from the planarizing film 40.
  • the protruding portion 30b and the embedded portion 30c are integrally formed. That is, the protruding portion 30b and the embedded portion 30c are formed of the same material.
  • the shape of the upper surface of the protrusion 30b may be a shape that can receive incident light as efficiently as possible in the region surrounded by the partition walls 50. Further, the protruding portion 30 b may have a size such that a part of the protruding portion 30 b is located above the wiring layer 21.
  • FIG. 2 is an example of a schematic top view of the solid-state imaging device 100.
  • the upper surface shape of the protrusion 30b of the optical waveguide 30 is a regular octagon.
  • the top surface shape of the hole 23 of the interlayer insulating film 20 is a circle.
  • the upper surface shape of the protruding portion 30b may be a desired shape such as a square, a rectangle, a polygon, a circle, or an ellipse.
  • the cross-sectional shape of the protrusion 30b may be a desired shape such as a square shape, a trapezoidal shape, or a lens shape. However, as the cross-sectional shape is closer to the lens shape, the light after passing through the color filter 60 can be condensed to the portion of the optical waveguide 30 in the hole 23 of the interlayer insulating film 20. Further, when viewed in a plan view, the protruding portion 30b may be sized to fit within a region corresponding to one pixel cell surrounded by the partition wall 50.
  • the planarizing film 40 separates adjacent protrusions 30b.
  • the planarizing film 40 is provided to adjust the surface step between the interlayer insulating film 20 and the optical waveguide 30 to be flat.
  • the planarizing film 40 is made of a material having a third refractive index lower than the second refractive index of the material constituting the optical waveguide 30. Examples of the material having the third refractive index include silicon oxide and acrylic thermosetting resin.
  • the planarizing film 40 has a thickness of about 0.2 ⁇ m. Further, a part of the planarizing film 40 fills the space between the adjacent protrusions 30b. That is, the adjacent optical waveguides 30 are separated by the planarization film 40. Further, no wiring is formed on the planarizing film 40.
  • the color filter 60 is formed above each of the plurality of optical waveguides 30.
  • the color filter 60 is made of a transparent polymer resin having a refractive index of about 1.6 to 1.7, for example, and is colored red (R), green (G), or blue (B).
  • the partition wall 50 is formed of silicon oxide (SiO 2 ) or the like formed using TEOS (tetraethoxysilane) gas or the like.
  • the height of the partition wall 50 is about 600 to 800 nm.
  • the refractive index of the partition 50 is about 1.5 to 1.6, which is smaller than the refractive index of the color filter 60.
  • the micro lens 70 is formed above each of the plurality of color filters 60.
  • the microlens 70 is a convex lens having a convex upper surface.
  • the diameter of the microlens 70 is substantially equal to the size of the pixel cell.
  • the micro lens 70 is made of a transparent polymer resin having a refractive index of about 1.6. For example, if the pixel cell is a square having a side length of 1.2 ⁇ m, the diameter of the microlens 70 is about 1.4 ⁇ m.
  • the color filter 60 is formed on the protrusion part 30b. At this time, the center positions of the photoelectric conversion unit 11 and the embedding unit 30c also coincide.
  • the center of the photoelectric conversion unit 11 and the center of the embedded part 30c coincide with each other, but the center of the protruding part 30b is the center of the embedded part 30c.
  • the center position is shifted in the direction approaching the center pixel (the center direction side of the imaging region).
  • FIG. 3 is a schematic top view of the solid-state imaging device 100, showing two-dimensionally how the planar position of the protrusion 30b in the peripheral pixels is shifted.
  • the upper surface shape of the protrusion part 30b has shown the example which is square.
  • FIG. 3 only the pixel cells of 3 rows ⁇ 3 columns are shown for the sake of simplicity of explanation.
  • the center position of the protrusion 30b is shifted from the center position of the hole 23 in a direction approaching the center pixel.
  • the distance from the center of the photoelectric conversion portion 11 to the center of the protruding portion 30b is defined as a shift amount a.
  • This shift amount a is smaller than the radius of the hole 23 (radius of the embedded portion).
  • the light that has passed through the optical member (lens) of the imaging device is irradiated to the peripheral pixels from above the center of the imaging region. Accordingly, external light is incident more obliquely on the pixel cells arranged at positions farther from the center of the imaging region. Therefore, by shifting the center position of the protrusion 30b from the center position of the photoelectric conversion unit 11 located below the protrusion 30b toward the center of the imaging region in the peripheral pixels, the amount of oblique light taken into the optical waveguide 30 can be reduced. Can be increased. As a result, the sensitivity of the photoelectric conversion unit 11 to oblique light can be improved.
  • the shift amount a of the protrusion 30b of the pixel cell located at the outermost periphery of the imaging region is set to about 240 nm, so that the microlens 70 and the color filter 60 are obtained.
  • the light that passes through and enters the protruding portion 30b enters the center of the embedded portion 30c.
  • the shift amount a of each pixel cell is the pixel from the center pixel to the target pixel cell by dividing the outermost shift amount a (240 nm) by the number of pixels from the center pixel to the outermost pixel cell. What is necessary is just to set to the value which multiplied the number.
  • the light L1 shown in FIG. 1B light enters the peripheral pixels at a larger angle than the central pixel.
  • the light L1 enters the optical waveguide 30 at a large angle so as to travel in the direction of the adjacent pixel cell after passing through the color filter 60.
  • the light L1 reaches the side wall of the protrusion 30b of the optical waveguide 30, but is reflected on the surface of the planarizing film 40 because the second refractive index is higher than the third refractive index.
  • the reflected light travels into the embedded portion 30 c of the optical waveguide 30.
  • this light does not enter the adjacent pixel cell, color mixing can be suppressed.
  • this light can be guided to the embedded portion 30c of the optical waveguide 30, it is possible to reduce the sensitivity difference between the central pixel and the peripheral pixels. As a result, the shading characteristics of the solid-state imaging device 100 are improved.
  • the center position of the projecting portion 30b is shifted from the center position of the photoelectric conversion unit 11 positioned below the center portion of the imaging region.
  • the center position of the protrusion 30b when viewed in plan is a direction away from the center of the imaging region with reference to the center position of the photoelectric conversion unit 11 positioned below the center position. It may be shifted to.
  • 4A to 4D, 5A to 5D, and 6A to 6D are cross-sectional views of the solid-state imaging device 100 in the manufacturing process. In addition, only the configuration of the unit pixel cell is shown in FIG.
  • a plurality of photoelectric conversion portions 11 are formed in a matrix in the semiconductor substrate 10.
  • a laminate film 20a made of a laminate of a plurality of films is formed by a CVD (Chemical Vapor Deposition) method or the like.
  • a plurality of wiring layers 21a and 21b are formed together in the multilayer film 20a by the damascene method. More specifically, first, a groove for forming a wiring is formed by etching in one layer of the laminate constituting the laminate film 20a. Then, a barrier metal film as a seed layer is formed on the bottom and side surfaces of the formed groove.
  • a resist pattern 22 for opening a portion of the stacked body film 20a that is above the photoelectric conversion unit 11 is formed by a lithography process, for example.
  • the hole 23 is formed by etching the laminated body film 20a by RIE (reactive ion etching) or the like (FIG. 4C).
  • the photoelectric conversion unit 11 may be exposed at the bottom of the hole 23, and an insulating film of about several tens of nm is formed on the bottom of the hole 23 in order to avoid damage to the surface of the photoelectric conversion unit 11 due to the formation of the hole 23. May remain.
  • the depth of the hole 23 is, for example, about 0.5 ⁇ m.
  • a second refractive index material film (first transparent film) is formed on the interlayer insulating film 20 as a second refractive index higher than the first refractive index of the material constituting the interlayer insulating film 20.
  • An optical waveguide material film 30a made of a material having a refractive index is formed.
  • the optical waveguide material film 30a preferably has a thickness sufficient to suppress variations in the film thickness of the optical waveguide material film 30a, for example, about 1.5 ⁇ m. Further, the entire surface region of the optical waveguide material film 30 a is higher than the upper surface 20 c of the protruding portion of the interlayer insulating film 20. Further, after the optical waveguide material film 30a is formed, the optical waveguide material film 30a may be planarized by, for example, CMP or etch back.
  • a resist pattern 31 for opening an upper portion of the optical waveguide material film 30a between the adjacent photoelectric conversion portions 11 is formed by a lithography process. Thereafter, an etching process such as RIE is performed using the resist pattern 31 as an etching mask. Thereby, the part which hits the upper part between the adjacent photoelectric conversion parts 11 in the optical waveguide material film 30a is removed. That is, in each hole 23 of the interlayer insulating film 20, a buried portion 30 c that fills each hole 23, and a protruding portion 30 b that is integrally formed with the buried portion 30 c and rises from the upper surface of the interlayer insulating film 20 are formed. In this manner, the optical waveguide 30 including the embedded portion 30c and the protruding portion 30b is formed.
  • the protrusion 30b has a larger planar shape than the opening of the hole 23 when viewed in plan.
  • an insulating film 40a (planarization film formation) made of a silicon oxide film is formed by CVD so as to completely cover the optical waveguide 30 and the exposed portion of the interlayer insulating film 20. Film) is deposited to about 0.5 ⁇ m. Thereby, the surface level difference between the interlayer insulating film 20 and the optical waveguide 30 can be adjusted to be flat.
  • the height of the surface of the insulating film 40a at the upper portion between the adjacent photoelectric conversion portions 11 is made to be the same as the upper surface of the protruding portion 30b by CMP, etch back, or the like.
  • CMP CMP
  • etch back or the like.
  • the planarization film 40 is formed. That is, the flattening process is performed so that the upper surface of the protruding portion 30b of the optical waveguide 30 is exposed.
  • an insulating film 50a (a partition wall forming film) made of the above-described TEOS material or the like is formed as a third refractive index material film on the optical waveguide 30 and the planarizing film 40 by the CVD method or the like.
  • the thickness of the insulating film 50a is about 0.7 ⁇ m, which is about the same as the thickness of the color filter 60 to be formed later.
  • a resist pattern 51 having a shape surrounding the lower protrusion 30b is formed on the insulating film 50a by a lithography process.
  • the partition wall 50 made of the third refractive index material film is formed.
  • the width of the partition 50 is about 0.2 ⁇ m.
  • the partition 50 is formed so as to surround the photoelectric conversion unit 11 when viewed in a plan view.
  • a color filter 60 is formed by embedding a color filter forming material in a region surrounded by the partition walls 50.
  • a microlens 70 is formed.
  • the solid-state imaging device 100 having the configuration shown in FIG. 1 can be manufactured.
  • FIG. 7 is a cross-sectional view showing a configuration of a solid-state imaging device 200 according to the second embodiment of the present invention.
  • FIG. 7 shows a cross-sectional structure of peripheral pixels.
  • the configuration of the central pixel is the same as that in the first embodiment.
  • the center position of the protrusion 30b is shifted in the direction approaching the center pixel, as in the first embodiment. Further, in the solid-state imaging device 200, the center positions of the partition wall 50 and the microlens 70 are shifted in the direction approaching the center pixel (the center direction side of the imaging region).
  • the distance from the center of the photoelectric conversion unit 11 to the center of the protrusion 30b is a
  • the distance from the center of the photoelectric conversion unit 11 to the center of the color filter 60 is b
  • the center of the photoelectric conversion unit 11 to the microlens 70 is set.
  • a ⁇ b ⁇ c is set.
  • a is smaller than the radius of the upper end portion of the hole 23 (radius of the upper end portion of the embedded portion 30c)
  • c is larger than the planar distance between the end portion of the projecting portion 30b from the central pixel side and the center of the photoelectric conversion portion 11. It is small, and b is set to an intermediate level between a and c.
  • Such a configuration makes it possible to efficiently guide light incident obliquely from the central portion of the imaging region to the peripheral direction to the optical waveguide 30 in the peripheral pixels, so that the sensitivity of the solid-state imaging device 200 is improved.
  • the light that has passed through the optical member (lens) of the imaging device is irradiated to the peripheral pixels from above the central portion of the imaging region. Therefore, the greater the distance from the center of the imaging region, the more external light enters obliquely.
  • the center positions of the microlens 70, the color filter 60 between the partition walls 50, and the protruding portion 30b are changed from the center position of the photoelectric conversion unit 11 positioned below the imaging region.
  • the shift amount is set to a ⁇ b ⁇ c.
  • the light quantity of the oblique light taken into the color filter 60 and the optical waveguide 30 can be increased.
  • the sensitivity of the photoelectric conversion unit 11 to oblique light can be improved.
  • a ⁇ b ⁇ c is satisfied, only the microlens 70 may be shifted in a state where the center position of the embedded portion 30 c, the center position of the protruding portion 30 b, and the center position of the color filter 60 are matched.
  • the microlens 70 and the color filter 60 may be shifted in a state where the center position of the embedded portion 30c and the center position of the protruding portion 30b are matched.
  • the above-mentioned a, b, and c of the pixel cell located at the outermost periphery of the imaging region may be set to about 120 nm, 160 nm, and 240 nm, respectively.
  • incident light passes through the center of the microlens 70, the color filter 60, and the protrusion part 30b, and injects into the center of the embedding part 30c.
  • the shift amount (a, b, c) of each pixel cell is obtained by dividing the shift amount of the outermost periphery by the number of pixels from the center pixel to the outermost pixel cell, from the center pixel to the target pixel cell. A value obtained by multiplying the number of pixels may be set.
  • the light is incident on the peripheral pixels at a larger angle than the central pixel.
  • the light L2 After passing through the microlens 70, the light L2 passes through the color filter 60 and enters the color filter 60 of the adjacent pixel cell at a large angle.
  • the light L ⁇ b> 2 reaches the partition 50, but is reflected on the surface of the partition 50 because the refractive index of the partition 50 is smaller than the refractive index of the color filter 60. Then, the reflected light travels again through the color filter 60 and into the optical waveguide 30.
  • the microlens 70 and the partition wall 50 are shifted in addition to the protruding portion 30b, so that incident light having a larger angle than that in the first embodiment is condensed into the optical waveguide 30. Is possible. As a result, since such light does not enter the adjacent pixel cell, color mixing can be further suppressed. Further, since such light can be guided to the optical waveguide 30, it is possible to reduce the sensitivity difference between the central pixel and the peripheral pixels. As a result, the shading characteristics of the solid-state imaging device 200 are further improved.
  • the center positions of the microlens 70, the color filter 60, the partition wall 50, and the protruding portion 30b are shifted from the center position of the photoelectric conversion unit 11 positioned below the center position of the imaging region.
  • the center positions of the microlens 70, the color filter 60, and the partition wall 50 are determined from the center of the imaging region with reference to the center position of the photoelectric conversion unit 11 located therebelow. You may shift in the direction to leave.
  • the solid-state imaging device 200 according to the present embodiment is characterized by the displacement of the planar positions of the microlenses 70, the partition walls 50, and the protrusions 30b of the peripheral pixels shown in FIG. This is the same as the solid-state imaging device 100 according to the first embodiment.
  • the method for manufacturing the solid-state imaging device 200 according to the present embodiment is basically the same as the method for manufacturing the solid-state imaging device 100 according to the first embodiment described above, and a description thereof will be omitted.
  • the solid-state imaging device is typically realized as an LSI that is an integrated circuit. These may be individually made into one chip, or may be made into one chip so as to include a part or all of them.
  • the present invention can be applied to a solid-state imaging device.
  • the present invention can be applied to various imaging devices such as a digital still camera and a digital video camera using a solid-state imaging device.

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Abstract

A solid-state image capture device (100) according to the present invention comprises a semiconductor substrate (10), a plurality of photoelectric conversion units (11) which are formed in a matrix upon the semiconductor substrate (10), an inter-layer insulating film (20) which is formed upon the semiconductor substrate (10), optical waveguide paths (30) which are formed above each of the plurality of photoelectric conversion units (11), color filters (60) which are formed above each of the plurality of optical waveguide paths (30), and partitions (50) which separate the adjacent color filters (60). Each of the plurality of optical waveguide paths (30) further comprises an embedded part (30c) which is embedded in the inter-layer insulating film (20), and a protrusion part (30b) which is formed protruding from the inter-layer insulating film (20). The protrusion part (30b) covers the upper face of the embedded part (30c) and the periphery of the embedded part (30c) in the inter-layer insulating film (20) in plan view.

Description

固体撮像装置、及びその製造方法Solid-state imaging device and manufacturing method thereof
　本発明は光導波路を備えた固体撮像装置、及びその製造方法に関する。 The present invention relates to a solid-state imaging device including an optical waveguide and a method for manufacturing the same.
　ＣＣＤ（Ｃｈａｒｇｅ　Ｃｏｕｐｌｅｄ　Ｄｅｖｉｃｅ）及びＭＯＳ（Ｍｅｔａｌ　Ｏｘｉｄｅ　Ｓｅｍｉｃｏｎｄｕｃｔｏｒ）イメージセンサに代表される固体撮像装置は、入射光を各画素のフォトダイオードで光電変換した電気信号を利用した半導体デバイスである。この固体撮像装置は、ビデオカメラ及びデジタルスチルカメラ等に搭載されている。 A solid-state imaging device represented by a CCD (Charge Coupled Device) and a MOS (Metal Oxide Semiconductor) image sensor is a semiconductor device using an electrical signal obtained by photoelectrically converting incident light by a photodiode of each pixel. This solid-state imaging device is mounted on a video camera, a digital still camera, or the like.
　固体撮像装置では入射光の光量を出来る限り損失することなく、効率的にフォトダイオードへ導くことが重要である。この目的のため考案された固体撮像装置の一般的な構成の一例について説明する。 In a solid-state imaging device, it is important to efficiently guide the light to the photodiode without losing the amount of incident light as much as possible. An example of a general configuration of a solid-state imaging device devised for this purpose will be described.
　図８は、特許文献１に記載の固体撮像装置３００の構成を示す断面図である。図８に示す固体撮像装置３００は、半導体基板１０１上に形成され、内部に配線を含む絶縁層１０３を有する。絶縁層１０３の受光部１０２の上部分に光導波路形成用穴が形成されており、当該光導波路形成用穴の中に透光性材料１１２を埋め込むことで光導波路１０５ａが形成されている。光導波路１０５ａの上方にはマイクロレンズ１０９が設けられている。このマイクロレンズ１０９の焦点は、光導波路１０５ａ内部、かつ、受光部１０２の表面近傍に設定されている。マイクロレンズ１０９が光導波路１０５ａの上方に存在することによりにより、入射した光は光導波路１０５ａ内に集光される。さらに光導波路１０５ａを、当該光導波路１０５ａ周囲の絶縁層１０３よりも屈折率の高い絶縁物層で構成することにより、光導波路１０５ａへ斜めに入射した光は散逸することなく、当該光導波路１０５ａの側壁で反射される。これにより、効率的に受光部１０２上へ光を伝播することが可能となる。 FIG. 8 is a cross-sectional view showing a configuration of the solid-state imaging device 300 described in Patent Document 1. A solid-state imaging device 300 illustrated in FIG. 8 includes an insulating layer 103 that is formed over a semiconductor substrate 101 and includes wiring therein. An optical waveguide forming hole is formed in the upper portion of the light receiving portion 102 of the insulating layer 103, and an optical waveguide 105a is formed by embedding a translucent material 112 in the optical waveguide forming hole. A microlens 109 is provided above the optical waveguide 105a. The focal point of the micro lens 109 is set in the optical waveguide 105 a and in the vicinity of the surface of the light receiving unit 102. Since the microlens 109 exists above the optical waveguide 105a, the incident light is collected in the optical waveguide 105a. Further, by configuring the optical waveguide 105a with an insulating layer having a refractive index higher than that of the insulating layer 103 around the optical waveguide 105a, light incident obliquely to the optical waveguide 105a is not scattered and the optical waveguide 105a Reflected by the side wall. As a result, light can be efficiently propagated onto the light receiving unit 102.
特開２００２－１１８２４５号公報JP 2002-118245 A
　しかしながら、特許文献１記載の構成では、マイクロレンズが光導波路の直上にある。このため、画素に垂直に近い角度で光が入射する場合には、光を有効に光導波路に集光することが可能であるが、固体撮像装置の画素アレイの中心部から離れた画素領域、特に周辺部の画素では入射光の内、低角度の光量成分が増加する。これにより、マイクロレンズだけでは光を光導波路へ集光できない場合がある。よって、光量損失が増大することで、感度特性の低下を招く。 However, in the configuration described in Patent Document 1, the microlens is directly above the optical waveguide. For this reason, when light is incident at an angle close to perpendicular to the pixel, it is possible to effectively collect the light into the optical waveguide, but the pixel region away from the center of the pixel array of the solid-state imaging device, In particular, in the peripheral pixels, the light amount component at a low angle in the incident light increases. As a result, there are cases where light cannot be collected on the optical waveguide only by the microlens. Therefore, the increase in the light loss causes a reduction in sensitivity characteristics.
　また、隣接する画素のマイクロレンズが接近又は接触し、さらに透光性材料が隣接する画素と連続して設けられている。このため、特に低角度で入射した光が透光性材料内を伝播し隣接する画素へ入射光が漏れこむことで混色が発生する。 Also, the microlenses of adjacent pixels approach or come into contact with each other, and a translucent material is provided continuously with the adjacent pixels. For this reason, color mixing occurs when light incident at a low angle propagates through the light-transmitting material and the incident light leaks to adjacent pixels.
　上記に鑑み、本発明は、感度特性の低下を抑制できるとともに、混色の発生を抑制できる固体撮像装置を提供することを目的とする。 In view of the above, an object of the present invention is to provide a solid-state imaging device capable of suppressing a decrease in sensitivity characteristics and suppressing the occurrence of color mixing.
　上記目的を達成するため、本発明の一形態に係る固体撮像装置は、半導体基板と、前記半導体基板に行列状に形成された複数の光電変換部と、前記半導体基板の上に形成された層間絶縁膜と、前記複数の光電変換部それぞれの上方に形成された光導波路と、複数の前記光導波路それぞれの上方に形成されたカラーフィルタと、隣接する前記カラーフィルタを分離する隔壁とを備え、前記複数の光導波路のそれぞれは、前記層間絶縁膜中に埋め込まれた埋め込み部と、前記層間絶縁膜から突出して形成された突出部とを含み、前記突出部は、前記埋め込み部の上面、及び平面視したときに前記層間絶縁膜における前記埋め込み部の周囲を被覆する。 In order to achieve the above object, a solid-state imaging device according to an embodiment of the present invention includes a semiconductor substrate, a plurality of photoelectric conversion units formed in a matrix on the semiconductor substrate, and an interlayer formed on the semiconductor substrate. An insulating film; an optical waveguide formed above each of the plurality of photoelectric conversion units; a color filter formed above each of the plurality of optical waveguides; and a partition that separates the adjacent color filters; Each of the plurality of optical waveguides includes an embedded portion embedded in the interlayer insulating film, and a protruding portion formed to protrude from the interlayer insulating film, the protruding portion including an upper surface of the embedded portion, and When viewed in plan, the periphery of the buried portion in the interlayer insulating film is covered.
　この構成によれば、隔壁により、画素毎にカラーフィルタが分離されているので、カラーフィルタの側面を経由して隣接画素に光が入射することを防止できる。さらに、層間絶縁膜上に、画素毎に突出部が形成されている。これにより、突出部が形成されている層において、光が隣接画素に入射することを防止できる。このように、本発明の一形態に係る固体撮像装置は、感度特性の低下を抑制できるとともに、混色の発生を抑制できる。 According to this configuration, since the color filter is separated for each pixel by the partition wall, it is possible to prevent light from entering the adjacent pixel via the side surface of the color filter. Furthermore, a protrusion is formed for each pixel on the interlayer insulating film. Thereby, in the layer in which the protrusion part is formed, it can prevent that light injects into an adjacent pixel. As described above, the solid-state imaging device according to one embodiment of the present invention can suppress a decrease in sensitivity characteristics and suppress the occurrence of color mixing.
　また、前記固体撮像装置は、さらに、隣接する前記突出部を分離する平坦化膜を備えてもよい。 The solid-state imaging device may further include a flattening film that separates the adjacent protrusions.
　また、前記突出部は、平面視したときに１画素セルに対応する前記隔壁に囲まれた領域内に収まる形状であってもよい。 In addition, the protruding portion may have a shape that fits in a region surrounded by the partition corresponding to one pixel cell when viewed in plan.
　また、前記埋め込み部と前記突出部とは同一の材料で形成されていてもよい。 Further, the embedded portion and the protruding portion may be formed of the same material.
　また、前記突出部の上面は、前記平坦化膜から露出していてもよい。 Further, the upper surface of the projecting portion may be exposed from the planarizing film.
　また、前記複数の光電変換部が形成されている撮像領域は、中央部と、前記中央部より外側に位置する周辺部とを含み、前記中央部に配置されている中央画素において、平面視した場合の前記埋め込み部の中心位置と前記突出部の中心位置とが一致しており、前記周辺部に配置されている周辺画素において、平面視した場合の前記突出部の中心位置が前記埋め込み部の中心位置に対して前記撮像領域の中央方向側にあってもよい。 The imaging region in which the plurality of photoelectric conversion units are formed includes a central part and a peripheral part located outside the central part, and is viewed in plan in a central pixel disposed in the central part. In this case, the center position of the embedding part and the center position of the projecting part coincide with each other, and the center position of the projecting part when viewed in plan is the peripheral pixel arranged in the perimeter part. You may be in the center direction side of the above-mentioned imaging field to the center position.
　この構成によれば、中央画素と周辺画素との感度差を低減することが可能となる。結果、当該固体撮像装置のシェーディング特性を向上できる。 According to this configuration, it is possible to reduce the sensitivity difference between the central pixel and the peripheral pixels. As a result, the shading characteristics of the solid-state imaging device can be improved.
　また、前記固体撮像装置は、さらに、複数の前記カラーフィルタそれぞれの上方に形成されたマイクロレンズを備え、前記周辺画素において、平面視した場合の前記隔壁の中心位置と、前記マイクロレンズの中心位置とが前記埋め込み部の中心位置に対して前記撮像領域の中央方向側にあってもよい。 In addition, the solid-state imaging device further includes a microlens formed above each of the plurality of color filters, and in the peripheral pixels, the center position of the partition wall when viewed in plan, and the center position of the microlens May be on the center direction side of the imaging region with respect to the center position of the embedded portion.
　この構成によれば、中央画素と周辺画素との感度差を、さらに低減することが可能となる。 According to this configuration, it is possible to further reduce the sensitivity difference between the central pixel and the peripheral pixels.
　また、前記周辺画素における、前記埋め込み部の中心位置と前記突出部の中心位置との第１のズレ量と、前記埋め込み部の中心位置と前記隔壁の中心位置との第２のズレ量と、前記埋め込み部の中心位置と前記マイクロレンズの中心位置との第３のズレ量とは、第１のズレ量≦第２のズレ量≦第３のズレ量の関係を満たしてもよい。 Further, in the peripheral pixel, a first shift amount between the center position of the embedded portion and the center position of the protruding portion, and a second shift amount between the center position of the embedded portion and the center position of the partition wall, The third deviation amount between the center position of the embedding part and the center position of the microlens may satisfy a relationship of first deviation amount ≦ second deviation amount ≦ third deviation amount.
　また、前記第１のズレ量は、前記埋め込み部の上端部の半径よりも小さく、前記第３のズレ量は、前記突出部の前記撮像領域の中央方向側の端部と前記光電変換部の中心位置との平面距離よりも小さくてもよい。 In addition, the first displacement amount is smaller than the radius of the upper end portion of the embedded portion, and the third displacement amount is an end portion of the projecting portion on the central direction side of the imaging region and the photoelectric conversion portion. It may be smaller than the planar distance from the center position.
　また、前記突出部の断面形状は、方形、台錐形、又はレンズ状形であってもよい。 Further, the cross-sectional shape of the protruding portion may be a square shape, a trapezoidal shape, or a lens shape.
　また、前記突出部の平面形状は、正方形、長方形、多角形、円形、又は楕円形であってもよい。 Further, the planar shape of the protruding portion may be a square, a rectangle, a polygon, a circle, or an ellipse.
　また、前記光導波路の屈折率は、前記平坦化膜の屈折率よりも大きく、前記カラーフィルタの屈折率は、前記隔壁の屈折率よりも大きくてもよい。 In addition, the refractive index of the optical waveguide may be larger than the refractive index of the planarization film, and the refractive index of the color filter may be larger than the refractive index of the partition wall.
　また、前記固体撮像装置は、さらに、前記層間絶縁膜に形成された配線を備え、平面視した場合に前記突出部の一部は前記配線と重なってもよい。 In addition, the solid-state imaging device may further include a wiring formed in the interlayer insulating film, and a part of the protruding portion may overlap the wiring when viewed in plan.
　また、本発明の一形態に係る固体撮像装置の製造方法は、半導体基板に行列状に複数の光電変換部を形成する工程と、前記半導体基板の上に層間絶縁膜を形成する工程と、前記層間絶縁膜の前記複数の光電変換部それぞれの上方に穴を形成する工程と、前記穴に埋め込まれた埋め込み部と、前記埋め込み部の上面、及び平面視したときに前記層間絶縁膜における前記埋め込み部の周囲を被覆し、かつ、前記層間絶縁膜から突出して形成された突出部とを含む光導波路を形成する工程と、隣接する前記突出部を分離する平坦化膜を形成する工程と、複数の前記光導波路それぞれの上方にカラーフィルタを形成する工程と、前記平坦化膜の上方に、隣接する前記カラーフィルタを分離する隔壁を形成する工程とを含む。 Further, a method for manufacturing a solid-state imaging device according to an aspect of the present invention includes a step of forming a plurality of photoelectric conversion units in a matrix on a semiconductor substrate, a step of forming an interlayer insulating film on the semiconductor substrate, Forming a hole above each of the plurality of photoelectric conversion portions of the interlayer insulating film, the embedded portion embedded in the hole, an upper surface of the embedded portion, and the embedded in the interlayer insulating film when viewed in plan A step of forming an optical waveguide that covers the periphery of the portion and includes a protruding portion that protrudes from the interlayer insulating film, a step of forming a planarizing film that separates the adjacent protruding portion, and a plurality of steps Forming a color filter above each of the optical waveguides, and forming a partition that separates the adjacent color filters above the planarizing film.
　これによれば、隔壁により、画素毎にカラーフィルタが分離されているので、カラーフィルタの側面を経由して隣接画素に光が入射することを防止できる。さらに、層間絶縁膜上に、画素毎に突出部が形成されている。これにより、突出部が形成されている層において、光が隣接画素に入射することを防止できる。このように、本発明の一形態に係る固体撮像装置の製造方法は、混色の発生を抑制できるとともに、感度特性を向上できる固体撮像装置を製造できる。 According to this, since the color filter is separated for each pixel by the partition wall, it is possible to prevent light from entering the adjacent pixel via the side surface of the color filter. Furthermore, a protrusion is formed for each pixel on the interlayer insulating film. Thereby, in the layer in which the protrusion part is formed, it can prevent that light injects into an adjacent pixel. As described above, the method for manufacturing a solid-state imaging device according to an aspect of the present invention can manufacture a solid-state imaging device that can suppress the occurrence of color mixing and can improve sensitivity characteristics.
　また、前記光導波路を形成する工程は、前記層間絶縁膜の上方に光導波路形成膜を形成する工程と、前記光導波路形成膜上における前記穴の上方にレジストパターンを形成する工程と、前記レジストパターンをエッチングマスクとして用いて、平面視した場合に、前記穴の開口よりも大きな前記突出部を形成する工程とを含んでもよい。 In addition, the step of forming the optical waveguide includes a step of forming an optical waveguide formation film above the interlayer insulating film, a step of forming a resist pattern above the hole on the optical waveguide formation film, and the resist Forming a projection larger than the opening of the hole when viewed in plan using the pattern as an etching mask.
　また、前記平坦化膜を形成する工程は、前記層間絶縁膜及び前記光導波路を被覆する平坦化膜形成膜を形成する工程と、ＣＭＰ（Ｃｈｅｍｉｃａｌ　Ｍｅｃｈａｎｉｃａｌ　Ｐｏｌｉｓｈｉｎｇ）又はエッチバックを用いて、前記平坦化膜形成膜から前記突出部の上面を露出させる工程とを含んでもよい。 Further, the step of forming the planarization film includes the step of forming a planarization film formation film that covers the interlayer insulating film and the optical waveguide, and the planarization using CMP (Chemical Mechanical Polishing) or etch back. Exposing the upper surface of the protruding portion from the film forming film.
　また、前記隔壁を形成する工程は、前記平坦化膜上に隔壁形成膜を形成する工程と、前記隔壁形成膜をエッチングすることで、平面視した場合に前記光電変換部を取り囲む前記隔壁を形成する工程とを含み、前記カラーフィルタを形成する工程では、前記隔壁で囲まれた領域に前記カラーフィルタ形成材料を埋め込むことで前記カラーフィルタを形成してもよい。 In addition, the step of forming the partition wall includes a step of forming a partition wall formation film on the planarizing film, and etching the partition wall formation film to form the partition wall that surrounds the photoelectric conversion unit when viewed in plan. In the step of forming the color filter, the color filter may be formed by embedding the color filter forming material in a region surrounded by the partition wall.
　なお、本発明は、このような固体撮像装置の機能の一部又は全てを実現する半導体集積回路（ＬＳＩ）として実現したり、このような固体撮像装置を備える撮像装置（カメラ）として実現したりできる。 The present invention can be realized as a semiconductor integrated circuit (LSI) that realizes part or all of the functions of such a solid-state imaging device, or as an imaging device (camera) including such a solid-state imaging device. it can.
　以上より、本発明は、感度特性の低下を抑制できるとともに、混色の発生を抑制できる固体撮像装置を提供できる。 As described above, the present invention can provide a solid-state imaging device capable of suppressing a decrease in sensitivity characteristics and suppressing the occurrence of color mixing.
図１Ａは、本発明の第１の実施形態に係る固体撮像装置の断面図である。FIG. 1A is a cross-sectional view of the solid-state imaging device according to the first embodiment of the present invention. 図１Ｂは、本発明の第１の実施形態に係る固体撮像装置の断面図である。FIG. 1B is a cross-sectional view of the solid-state imaging device according to the first embodiment of the present invention. 図２は、本発明の第１の実施形態に係る固体撮像装置の平面図である。FIG. 2 is a plan view of the solid-state imaging device according to the first embodiment of the present invention. 図３は、本発明の第１の実施形態に係る固体撮像装置の平面図である。FIG. 3 is a plan view of the solid-state imaging device according to the first embodiment of the present invention. 図４Ａは、本発明の第１の実施形態に係る固体撮像装置の製造過程における断面図である。FIG. 4A is a sectional view of the solid-state imaging device according to the first embodiment of the present invention in the manufacturing process. 図４Ｂは、本発明の第１の実施形態に係る固体撮像装置の製造過程における断面図である。FIG. 4B is a cross-sectional view in the process of manufacturing the solid-state imaging device according to the first embodiment of the present invention. 図４Ｃは、本発明の第１の実施形態に係る固体撮像装置の製造過程における断面図である。FIG. 4C is a cross-sectional view in the process of manufacturing the solid-state imaging device according to the first embodiment of the present invention. 図４Ｄは、本発明の第１の実施形態に係る固体撮像装置の製造過程における断面図である。FIG. 4D is a cross-sectional view of the solid-state imaging device according to the first embodiment of the present invention in the manufacturing process. 図５Ａは、本発明の第１の実施形態に係る固体撮像装置の製造過程における断面図である。FIG. 5A is a cross-sectional view in the process of manufacturing the solid-state imaging device according to the first embodiment of the present invention. 図５Ｂは、本発明の第１の実施形態に係る固体撮像装置の製造過程における断面図である。FIG. 5B is a cross-sectional view of the solid-state imaging device according to the first embodiment of the present invention in the manufacturing process. 図５Ｃは、本発明の第１の実施形態に係る固体撮像装置の製造過程における断面図である。FIG. 5C is a cross-sectional view in the process of manufacturing the solid-state imaging device according to the first embodiment of the present invention. 図５Ｄは、本発明の第１の実施形態に係る固体撮像装置の製造過程における断面図である。FIG. 5D is a cross-sectional view of the solid-state imaging device according to the first embodiment of the present invention in the manufacturing process. 図６Ａは、本発明の第１の実施形態に係る固体撮像装置の製造過程における断面図である。FIG. 6A is a cross-sectional view in the process of manufacturing the solid-state imaging device according to the first embodiment of the present invention. 図６Ｂは、本発明の第１の実施形態に係る固体撮像装置の製造過程における断面図である。FIG. 6B is a cross-sectional view of the solid-state imaging device according to the first embodiment of the present invention in the manufacturing process. 図６Ｃは、本発明の第１の実施形態に係る固体撮像装置の製造過程における断面図である。FIG. 6C is a cross-sectional view in the process of manufacturing the solid-state imaging device according to the first embodiment of the present invention. 図６Ｄは、本発明の第１の実施形態に係る固体撮像装置の製造過程における断面図である。FIG. 6D is a cross-sectional view of the solid-state imaging device according to the first embodiment of the present invention in the manufacturing process. 図７は、本発明の第２の実施形態に係る固体撮像装置の断面図である。FIG. 7 is a cross-sectional view of a solid-state imaging device according to the second embodiment of the present invention. 図８は、従来の固体撮像装置の断面図である。FIG. 8 is a cross-sectional view of a conventional solid-state imaging device.
　（第１の実施形態）
　以下、本発明の第１の実施形態に係る固体撮像装置について、図面を参照しながら説明する。なお、以下で説明する実施形態は、いずれも本発明の好ましい一具体例を示すものである。以下の実施形態で示される数値、形状、材料、構成要素、構成要素の配置位置及び接続形態などは、一例であり、本発明を限定する主旨ではない。本発明は、請求の範囲だけによって限定される。よって、以下の実施形態における構成要素のうち、本発明の最上位概念を示す独立請求項に記載されていない構成要素については、本発明の課題を達成するのに必ずしも必要ではないが、より好ましい形態を構成するものとして説明される。 (First embodiment)
Hereinafter, a solid-state imaging device according to a first embodiment of the present invention will be described with reference to the drawings. Note that each of the embodiments described below shows a preferred specific example of the present invention. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. The present invention is limited only by the claims. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims showing the highest concept of the present invention are not necessarily required to achieve the object of the present invention, but are more preferable. It will be described as constituting a form.
　図１Ａ及び図１Ｂは、本発明の第１の実施形態に係る固体撮像装置１００の構成を示す断面図である。図１Ａは、撮像領域（画素アレイ）の中央部に配置されている画素セル（以下、中央画素）の断面図である。図１Ｂは、撮像領域の中央から離れた周辺部に配置されている画素セル（周辺画素）の断面図である。ここで、周辺部は、中央部より撮像領域の外側に位置する領域である。 1A and 1B are cross-sectional views showing the configuration of the solid-state imaging device 100 according to the first embodiment of the present invention. FIG. 1A is a cross-sectional view of a pixel cell (hereinafter referred to as a central pixel) disposed in the central portion of an imaging region (pixel array). FIG. 1B is a cross-sectional view of a pixel cell (peripheral pixel) arranged in a peripheral portion away from the center of the imaging region. Here, the peripheral part is an area located outside the imaging area from the central part.
　図１Ａ及び図１Ｂに示すように、本発明の第１の実施形態に係る固体撮像装置１００は、半導体基板１０と、半導体基板１０に行列状に形成された複数の光電変換部１１と、半導体基板１０上に形成された層間絶縁膜２０と、層間絶縁膜２０上に画素セル毎に形成された光導波路３０と、層間絶縁膜２０上の光導波路３０の周囲に形成された平坦化膜４０と、光導波路３０及び平坦化膜４０上に形成され、有機材料に顔料が分散されてなるカラーフィルタ６０と、隣接するカラーフィルタ６０を分離する、絶縁膜からなる隔壁５０と、カラーフィルタ６０上に形成され、入射光を光電変換部１１に集光するマイクロレンズ７０とを備えている。 As shown in FIGS. 1A and 1B, a solid-state imaging device 100 according to the first embodiment of the present invention includes a semiconductor substrate 10, a plurality of photoelectric conversion units 11 formed in a matrix on the semiconductor substrate 10, and a semiconductor. Interlayer insulating film 20 formed on substrate 10, optical waveguide 30 formed for each pixel cell on interlayer insulating film 20, and planarization film 40 formed around optical waveguide 30 on interlayer insulating film 20. A color filter 60 formed on the optical waveguide 30 and the flattening film 40, in which a pigment is dispersed in an organic material, a partition wall 50 made of an insulating film that separates adjacent color filters 60, and the color filter 60. And a microlens 70 that condenses incident light on the photoelectric conversion unit 11.
　光電変換部１１は、例えば、フォトダイオードである、入射光を電気信号に光電変換する。 The photoelectric conversion unit 11 is, for example, a photodiode, and photoelectrically converts incident light into an electrical signal.
　層間絶縁膜２０は、複数の膜が積層された積層体である。各膜は、後述する光導波路３０を構成する材料の第２屈折率より低い第１屈折率の材料からなる。この第１屈折率の材料としては、例えば、屈折率が１．４５のＢＰＳＧ（Ｂｏｒｏｎ　Ｐｈｏｓｐｈｏｒｏｕｓ　Ｓｉｌｉｃａｔｅ　Ｇｌａｓｓ）、及びＮＳＧ（Ｎｏｎｅ－ｄｏｐｅｄ　Ｓｉｌｉｃａｔｅ　Ｇｌａｓｓ）などの酸化シリコン、並びに炭化シリコン等の絶縁体材料が挙げられる。 The interlayer insulating film 20 is a stacked body in which a plurality of films are stacked. Each film is made of a material having a first refractive index lower than a second refractive index of a material constituting the optical waveguide 30 described later. Examples of the first refractive index material include silicon oxide such as BPSG (Boron Phosphorous Silicate Glass) and NSG (None-doped Silicate Glass) having a refractive index of 1.45, and insulator materials such as silicon carbide. Can be mentioned.
　この層間絶縁膜２０は、表面領域において、光電変換部１１の上方に当たる部分に穴２３を有する。この穴２３を囲む層間絶縁膜２０の内部領域には、例えばＣｕなどの金属を主材料とする複数の配線層２１（配線層２１ａ及び配線層２１ｂ）が形成されている。これら配線層２１は、光電変換部１１への光の入射を妨げないように、層間絶縁膜２０における、隣り合う光電変換部１１の間の上方に当たる部分に配置されている。ここで、単位画素セルの寸法が、例えば１．４μｍ２程度の場合、層間絶縁膜２０の膜厚は０．５μｍ程度である。また、穴２３の径は、光電変換部１１の幅とほぼ等しく、例えば０．９μｍ程度である。 The interlayer insulating film 20 has a hole 23 in a portion of the surface region that is above the photoelectric conversion unit 11. In the inner region of the interlayer insulating film 20 surrounding the hole 23, a plurality of wiring layers 21 (a wiring layer 21a and a wiring layer 21b) mainly made of metal such as Cu are formed. These wiring layers 21 are disposed in the upper part of the interlayer insulating film 20 between the adjacent photoelectric conversion units 11 so as not to prevent light from entering the photoelectric conversion units 11. Here, when the dimension of the unit pixel cell is, for example, about 1.4 μm 2 , the film thickness of the interlayer insulating film 20 is about 0.5 μm. Further, the diameter of the hole 23 is substantially equal to the width of the photoelectric conversion unit 11 and is, for example, about 0.9 μm.
　光導波路３０は、複数の光電変換部１１それぞれの上方に形成されている。この光導波路３０は、透光性を有し、層間絶縁膜２０の第１屈折率及び後述する平坦化膜４０を構成する材料の第３屈折率より高い第２屈折率の材料からなる。この第２屈折率の材料としては、例えば、屈折率が１．８～１．９であるＴｉＯ分散ポリイミド等のＴｉＯを含む有機材料、又は屈折率が２．０の窒化シリコン等が挙げられる。 The optical waveguide 30 is formed above each of the plurality of photoelectric conversion units 11. The optical waveguide 30 is translucent and is made of a material having a second refractive index higher than a first refractive index of the interlayer insulating film 20 and a third refractive index of a material constituting the planarizing film 40 described later. Examples of the second refractive index material include an organic material containing TiO such as TiO-dispersed polyimide having a refractive index of 1.8 to 1.9, or silicon nitride having a refractive index of 2.0.
　この光導波路３０は、層間絶縁膜２０の穴２３内に埋め込まれた埋め込み部３０ｃと、層間絶縁膜２０よりも上方に形成された部分（すなわち穴２３からはみ出した部分）である突出部３０ｂとを含む。 The optical waveguide 30 includes an embedded portion 30c embedded in the hole 23 of the interlayer insulating film 20, and a protruding portion 30b that is a portion formed above the interlayer insulating film 20 (that is, a portion protruding from the hole 23). including.
　突出部３０ｂは、層間絶縁膜２０から突出して形成されており、埋め込み部３０ｃの上面を被覆する。言い換えると、突出部３０ｂは、埋め込み部３０ｃの周囲の層間絶縁膜２０の上面に乗り上げ、埋め込み部３０ｃ周囲の層間絶縁膜２０を被覆している。すなわち、光導波路３０は層間絶縁膜２０における穴２３の上端部のコーナー部分を完全に被覆する構成となっている。また、突出部３０ｂの上面は、平坦化膜４０から露出している。 The protruding portion 30b is formed to protrude from the interlayer insulating film 20, and covers the upper surface of the embedded portion 30c. In other words, the protruding portion 30b rides on the upper surface of the interlayer insulating film 20 around the buried portion 30c and covers the interlayer insulating film 20 around the buried portion 30c. That is, the optical waveguide 30 is configured to completely cover the corner portion of the upper end portion of the hole 23 in the interlayer insulating film 20. Further, the upper surface of the protruding portion 30 b is exposed from the planarizing film 40.
　また、突出部３０ｂと埋め込み部３０ｃとは一体に形成されている。つまり、突出部３０ｂと埋め込み部３０ｃとは同一の材料で形成されている。 Further, the protruding portion 30b and the embedded portion 30c are integrally formed. That is, the protruding portion 30b and the embedded portion 30c are formed of the same material.
　ここで、突出部３０ｂの上面形状は、隔壁５０で囲まれた領域内でできるだけ入射光を無駄なく受光できる形状であればよい。また、突出部３０ｂは、当該突出部３０ｂの一部が、配線層２１の上方に位置する程度の大きさとなってもよい。 Here, the shape of the upper surface of the protrusion 30b may be a shape that can receive incident light as efficiently as possible in the region surrounded by the partition walls 50. Further, the protruding portion 30 b may have a size such that a part of the protruding portion 30 b is located above the wiring layer 21.
　図２は、固体撮像装置１００の上面模式図の一例である。図２に示すように光導波路３０の突出部３０ｂの上面形状は正八角形である。また、層間絶縁膜２０の穴２３の上面形状は円である。このように、突出部３０ｂの上面形状を正八角形とすることにより、画素セルに対し上下左右から入射する光に対し対称となるので、こられの光を均等に集光できる。なお、突出部３０ｂの上面形状は、正方形、長方形、多角形、円形、又は楕円形等、所望の形状でよい。また、突出部３０ｂの断面形状は、方形、台錐形、又はレンズ状形等、所望の形でよい。ただし、断面形状がレンズ形状に近いほど、カラーフィルタ６０を透過した後の光を層間絶縁膜２０の穴２３内の光導波路３０の部分へより集光できる。また、平面視した場合に、突出部３０ｂは隔壁５０に囲まれた１画素セルに対応する領域内に収まる大きさであってもよい。 FIG. 2 is an example of a schematic top view of the solid-state imaging device 100. As shown in FIG. 2, the upper surface shape of the protrusion 30b of the optical waveguide 30 is a regular octagon. The top surface shape of the hole 23 of the interlayer insulating film 20 is a circle. Thus, by making the upper surface shape of the protruding portion 30b a regular octagon, the light is symmetric with respect to light incident from the top, bottom, left, and right with respect to the pixel cell, so that the light can be uniformly collected. In addition, the upper surface shape of the protrusion part 30b may be a desired shape such as a square, a rectangle, a polygon, a circle, or an ellipse. Moreover, the cross-sectional shape of the protrusion 30b may be a desired shape such as a square shape, a trapezoidal shape, or a lens shape. However, as the cross-sectional shape is closer to the lens shape, the light after passing through the color filter 60 can be condensed to the portion of the optical waveguide 30 in the hole 23 of the interlayer insulating film 20. Further, when viewed in a plan view, the protruding portion 30b may be sized to fit within a region corresponding to one pixel cell surrounded by the partition wall 50.
　平坦化膜４０は、隣接する突出部３０ｂを分離する。また、この平坦化膜４０は、層間絶縁膜２０と光導波路３０との表面段差を平坦に調整するために設けられている。この平坦化膜４０は、光導波路３０を構成する材料の第２屈折率より低い第３屈折率の材料からなる。この第３屈折率の材料としては、例えば、酸化シリコン、及びアクリル系熱硬化樹脂等が挙げられる。平坦化膜４０は、０．２μｍ程度の膜厚である。また、平坦化膜４０の一部が隣り合う突出部３０ｂの間を埋めている。つまり、この平坦化膜４０により、隣り合う光導波路３０が分離されている。また、平坦化膜４０には、配線は形成されていない。 The planarizing film 40 separates adjacent protrusions 30b. The planarizing film 40 is provided to adjust the surface step between the interlayer insulating film 20 and the optical waveguide 30 to be flat. The planarizing film 40 is made of a material having a third refractive index lower than the second refractive index of the material constituting the optical waveguide 30. Examples of the material having the third refractive index include silicon oxide and acrylic thermosetting resin. The planarizing film 40 has a thickness of about 0.2 μm. Further, a part of the planarizing film 40 fills the space between the adjacent protrusions 30b. That is, the adjacent optical waveguides 30 are separated by the planarization film 40. Further, no wiring is formed on the planarizing film 40.
　カラーフィルタ６０は、複数の光導波路３０それぞれの上方に形成されている。このカラーフィルタ６０は、屈折率が例えば１．６～１．７程度の透明高分子樹脂からなり、赤（Ｒ）、緑（Ｇ）又は青（Ｂ）に着色されている。 The color filter 60 is formed above each of the plurality of optical waveguides 30. The color filter 60 is made of a transparent polymer resin having a refractive index of about 1.6 to 1.7, for example, and is colored red (R), green (G), or blue (B).
　隔壁５０は、ＴＥＯＳ（テトラエトキシシラン）ガス等を用いて形成される酸化シリコン（ＳｉＯ２）等で形成される。この隔壁５０の高さは６００～８００ｎｍ程度である。また、隔壁５０の屈折率は１．５～１．６程度であり、カラーフィルタ６０の屈折率よりも小さい。 The partition wall 50 is formed of silicon oxide (SiO 2 ) or the like formed using TEOS (tetraethoxysilane) gas or the like. The height of the partition wall 50 is about 600 to 800 nm. The refractive index of the partition 50 is about 1.5 to 1.6, which is smaller than the refractive index of the color filter 60.
　マイクロレンズ７０は、複数のカラーフィルタ６０それぞれの上方に形成されている。このマイクロレンズ７０は上面が凸形状となっている凸レンズである。マイクロレンズ７０の直径は画素セルのサイズとほぼ同等である。このマイクロレンズ７０は、屈折率が１．６程度の透明高分子樹脂等で構成されている。例えば、画素セルが、一辺の長さが１．２μｍの正方形であれば、マイクロレンズ７０の直径は１．４μｍ程度である。 The micro lens 70 is formed above each of the plurality of color filters 60. The microlens 70 is a convex lens having a convex upper surface. The diameter of the microlens 70 is substantially equal to the size of the pixel cell. The micro lens 70 is made of a transparent polymer resin having a refractive index of about 1.6. For example, if the pixel cell is a square having a side length of 1.2 μm, the diameter of the microlens 70 is about 1.4 μm.
　次に、固体撮像装置１００の中央画素と周辺画素との構成物の位置的差異について説明する。 Next, the positional difference between the central pixel and the peripheral pixel of the solid-state imaging device 100 will be described.
　図１Ａに示すように、中央画素では、穴２３の中心、すなわち埋め込み部３０ｃの中心と、突出部３０ｂの中心とは一致している。そして、突出部３０ｂ上にカラーフィルタ６０が形成されている。この時、光電変換部１１と埋め込み部３０ｃとの中心位置も一致している。 As shown in FIG. 1A, in the center pixel, the center of the hole 23, that is, the center of the embedded portion 30c and the center of the protruding portion 30b coincide. And the color filter 60 is formed on the protrusion part 30b. At this time, the center positions of the photoelectric conversion unit 11 and the embedding unit 30c also coincide.
　一方、図１Ｂに示すように、撮像領域の周辺部の画素セルでは、光電変換部１１の中心と埋め込み部３０ｃの中心とは一致しているが、突出部３０ｂの中心は、埋め込み部３０ｃの中心位置に対し、中央画素に近づく方向（撮像領域の中央方向側）にずれている。 On the other hand, as shown in FIG. 1B, in the pixel cell in the peripheral part of the imaging region, the center of the photoelectric conversion unit 11 and the center of the embedded part 30c coincide with each other, but the center of the protruding part 30b is the center of the embedded part 30c. The center position is shifted in the direction approaching the center pixel (the center direction side of the imaging region).
　図３は、周辺画素における突出部３０ｂの平面位置のずれの様子を二次元的に示す、固体撮像装置１００の上面模式図である。なお、図３では突出部３０ｂの上面形状が正方形の例を示している。また、図３では、説明の簡略化のため３行×３列の画素セルのみを記載している。 FIG. 3 is a schematic top view of the solid-state imaging device 100, showing two-dimensionally how the planar position of the protrusion 30b in the peripheral pixels is shifted. In addition, in FIG. 3, the upper surface shape of the protrusion part 30b has shown the example which is square. In FIG. 3, only the pixel cells of 3 rows × 3 columns are shown for the sake of simplicity of explanation.
　周辺画素では、穴２３の中心位置に対して突出部３０ｂの中心位置が中央画素に近づく方向にずれている。 In the peripheral pixels, the center position of the protrusion 30b is shifted from the center position of the hole 23 in a direction approaching the center pixel.
　ここで光電変換部１１の中心から、突出部３０ｂの中心までの距離をずらし量ａとする。このずらし量ａは穴２３の半径（埋め込み部の半径）より小さい。 Here, the distance from the center of the photoelectric conversion portion 11 to the center of the protruding portion 30b is defined as a shift amount a. This shift amount a is smaller than the radius of the hole 23 (radius of the embedded portion).
　このような構成により、周辺画素において、撮像領域の中央から周辺方向へ斜めに入射する光を効率的に光導波路３０に導くことが可能となるので、固体撮像装置１００の感度が向上する。 With such a configuration, light incident obliquely from the center of the imaging region to the peripheral direction can be efficiently guided to the optical waveguide 30 in the peripheral pixels, so that the sensitivity of the solid-state imaging device 100 is improved.
　また、撮像装置の光学部材（レンズ）を通過した光は撮像領域の中心上方から周辺画素に照射される。従って、撮像領域の中心から遠い位置に配置されている画素セルほど、外光がより斜めに入射することになる。よって、周辺画素において、突出部３０ｂの各中心位置を、その下方に位置する光電変換部１１の中心位置から撮像領域の中心に向かってずらすことにより、光導波路３０に取り込まれる斜め光の光量を増加させることができる。結果として光電変換部１１の斜め光に対する感度を向上させることができる。 Further, the light that has passed through the optical member (lens) of the imaging device is irradiated to the peripheral pixels from above the center of the imaging region. Accordingly, external light is incident more obliquely on the pixel cells arranged at positions farther from the center of the imaging region. Therefore, by shifting the center position of the protrusion 30b from the center position of the photoelectric conversion unit 11 located below the protrusion 30b toward the center of the imaging region in the peripheral pixels, the amount of oblique light taken into the optical waveguide 30 can be reduced. Can be increased. As a result, the sensitivity of the photoelectric conversion unit 11 to oblique light can be improved.
　例えば、周辺画素での光の入射角度が４°の場合、撮像領域の最外周に位置する画素セルの突出部３０ｂのずらし量ａを２４０ｎｍ程度にすることで、マイクロレンズ７０、及びカラーフィルタ６０を透過し突出部３０ｂに入射した光が、埋め込み部３０ｃの中心に入射する。また、各画素セルのずらし量ａは、最外周のずらし量ａ（２４０ｎｍ）を、中心画素から最外周の画素セルまでの画素数で割った値に、中心画素から対象の画素セルまでの画素数を掛けた値に設定すればよい。 For example, when the incident angle of light at the peripheral pixels is 4 °, the shift amount a of the protrusion 30b of the pixel cell located at the outermost periphery of the imaging region is set to about 240 nm, so that the microlens 70 and the color filter 60 are obtained. The light that passes through and enters the protruding portion 30b enters the center of the embedded portion 30c. The shift amount a of each pixel cell is the pixel from the center pixel to the target pixel cell by dividing the outermost shift amount a (240 nm) by the number of pixels from the center pixel to the outermost pixel cell. What is necessary is just to set to the value which multiplied the number.
　ここで、図１Ｂに示す光Ｌ１のように、周辺画素には、中央画素に比べて大きな角度で光が入射する。この光Ｌ１は、カラーフィルタ６０を透過した後に隣接する画素セル方向へ進行するような大きな角度で光導波路３０に入射する。光Ｌ１は、光導波路３０の突出部３０ｂの側壁に達するが、第２屈折率が第３屈折率より高いことにより平坦化膜４０の表面で反射する。そして、反射した光が、光導波路３０の埋め込み部３０ｃ内部へと進行する。その結果、この光が隣接する画素セルへ侵入することがないので、混色を抑制することができる。さらに、この光を光導波路３０の埋め込み部３０ｃに導くことが可能となるので、中央画素と周辺画素との感度差を低減することが可能となる。結果、固体撮像装置１００のシェーディング特性が向上する。 Here, like the light L1 shown in FIG. 1B, light enters the peripheral pixels at a larger angle than the central pixel. The light L1 enters the optical waveguide 30 at a large angle so as to travel in the direction of the adjacent pixel cell after passing through the color filter 60. The light L1 reaches the side wall of the protrusion 30b of the optical waveguide 30, but is reflected on the surface of the planarizing film 40 because the second refractive index is higher than the third refractive index. Then, the reflected light travels into the embedded portion 30 c of the optical waveguide 30. As a result, since this light does not enter the adjacent pixel cell, color mixing can be suppressed. Furthermore, since this light can be guided to the embedded portion 30c of the optical waveguide 30, it is possible to reduce the sensitivity difference between the central pixel and the peripheral pixels. As a result, the shading characteristics of the solid-state imaging device 100 are improved.
　なお、上記説明では、突出部３０ｂの中心位置を、その下方に位置する光電変換部１１の中心位置から撮像領域の中心に近づく方向にずらす場合を説明した。しかし、カメラなどが要求する光学特性に応じて、平面的に見た場合の突出部３０ｂの中心位置を、その下方に位置する光電変換部１１の中心位置を基準として撮像領域の中心から離れる方向にずらしてもよい。 In the above description, the case where the center position of the projecting portion 30b is shifted from the center position of the photoelectric conversion unit 11 positioned below the center portion of the imaging region has been described. However, depending on the optical characteristics required by the camera or the like, the center position of the protrusion 30b when viewed in plan is a direction away from the center of the imaging region with reference to the center position of the photoelectric conversion unit 11 positioned below the center position. It may be shifted to.
　続いて、固体撮像装置１００の製造方法について説明する。図４Ａ～図４Ｄ、図５Ａ～図５Ｄ、及び図６Ａ～図６Ｄは、製造工程における固体撮像装置１００の断面図である。また、同図において、単位画素セルの構成のみを図示している。 Subsequently, a method for manufacturing the solid-state imaging device 100 will be described. 4A to 4D, 5A to 5D, and 6A to 6D are cross-sectional views of the solid-state imaging device 100 in the manufacturing process. In addition, only the configuration of the unit pixel cell is shown in FIG.
　まず、半導体基板１０内に複数の光電変換部１１を行列状に形成する。次に、半導体基板１０上に、第１屈折率材料膜として、複数の膜の積層体からなる積層体膜２０ａをＣＶＤ（Ｃｈｅｍｉｃａｌ　Ｖａｐｏｒ　Ｄｅｐｏｓｉｔｉｏｎ）法などにより形成する。この際、ダマシン法により、積層体膜２０ａ内に複数の配線層２１ａ及び２１ｂを併せて形成する。より詳細には、まず、積層体膜２０ａを構成する積層体の１層中に、配線を形成するための溝をエッチングにより形成する。そして、形成した溝の底面及び側面にシード層であるバリアメタル膜を形成する。その後、溝内部のバリアメタル膜上に電解めっきにより銅を堆積する。次に、溝の外部に堆積した導電材料をＣＭＰ（Ｃｈｅｍｉｃａｌ　Ｍｅｃｈａｎｉｃａｌ　Ｐｏｌｉｓｈｉｎｇ）により除去する。この工程を各配線層について行うことで、図４Ａに示すように、積層体膜２０ａに埋め込まれた複数の配線層２１ａ及び２１ｂを形成することができる。 First, a plurality of photoelectric conversion portions 11 are formed in a matrix in the semiconductor substrate 10. Next, on the semiconductor substrate 10, as a first refractive index material film, a laminate film 20a made of a laminate of a plurality of films is formed by a CVD (Chemical Vapor Deposition) method or the like. At this time, a plurality of wiring layers 21a and 21b are formed together in the multilayer film 20a by the damascene method. More specifically, first, a groove for forming a wiring is formed by etching in one layer of the laminate constituting the laminate film 20a. Then, a barrier metal film as a seed layer is formed on the bottom and side surfaces of the formed groove. Thereafter, copper is deposited on the barrier metal film inside the groove by electrolytic plating. Next, the conductive material deposited outside the trench is removed by CMP (Chemical Mechanical Polishing). By performing this process for each wiring layer, a plurality of wiring layers 21a and 21b embedded in the multilayer film 20a can be formed as shown in FIG. 4A.
　次に、図４Ｂに示すように、例えば、リソグラフィ工程により、積層体膜２０ａにおける、光電変換部１１の上方に当たる部分を開口するためのレジストパターン２２を形成する。その後、ＲＩＥ（反応性イオンエッチング）などで積層体膜２０ａをエッチングすることにより穴２３を形成する（図４Ｃ）。ここで、穴２３の底において、光電変換部１１が露出してもよいし、穴２３の形成による光電変換部１１表面へのダメージを避けるため、穴２３の底に、数１０ｎｍ程度の絶縁膜を残存させてよい。この穴２３の深さは、例えば０．５μｍ程度である。 Next, as shown in FIG. 4B, a resist pattern 22 for opening a portion of the stacked body film 20a that is above the photoelectric conversion unit 11 is formed by a lithography process, for example. Then, the hole 23 is formed by etching the laminated body film 20a by RIE (reactive ion etching) or the like (FIG. 4C). Here, the photoelectric conversion unit 11 may be exposed at the bottom of the hole 23, and an insulating film of about several tens of nm is formed on the bottom of the hole 23 in order to avoid damage to the surface of the photoelectric conversion unit 11 due to the formation of the hole 23. May remain. The depth of the hole 23 is, for example, about 0.5 μm.
　次に、図４Ｄに示すように、層間絶縁膜２０上に、第２屈折率材料膜（第１の透明膜）として、当該層間絶縁膜２０を構成する材料の第１屈折率より高い第２屈折率の材料からなる光導波路材料膜３０ａを形成する。この光導波路材料膜３０ａは、当該光導波路材料膜３０ａの膜厚のばらつきを抑制するのに十分な厚み、例えば１．５μｍ程度を有することが好ましい。また、光導波路材料膜３０ａの表面領域の全体が、層間絶縁膜２０の突出部の上面２０ｃよりも高くなっている。また、光導波路材料膜３０ａを形成した後、例えば、ＣＭＰ又はエッチバック等により、当該光導波路材料膜３０ａを平坦化してもよい。 Next, as shown in FIG. 4D, a second refractive index material film (first transparent film) is formed on the interlayer insulating film 20 as a second refractive index higher than the first refractive index of the material constituting the interlayer insulating film 20. An optical waveguide material film 30a made of a material having a refractive index is formed. The optical waveguide material film 30a preferably has a thickness sufficient to suppress variations in the film thickness of the optical waveguide material film 30a, for example, about 1.5 μm. Further, the entire surface region of the optical waveguide material film 30 a is higher than the upper surface 20 c of the protruding portion of the interlayer insulating film 20. Further, after the optical waveguide material film 30a is formed, the optical waveguide material film 30a may be planarized by, for example, CMP or etch back.
　次に、図５Ａに示すように、例えば、光導波路材料膜３０ａにおける、隣り合う光電変換部１１の間の上方に当たる部分を開口するためのレジストパターン３１をリソグラフィ工程により形成する。その後、レジストパターン３１をエッチングマスクとして用いて、ＲＩＥなどのエッチング処理を実施する。これにより、光導波路材料膜３０ａにおける、隣り合う光電変換部１１の間の上方に当たる部分が除去される。つまり、層間絶縁膜２０の各穴２３に、当該各穴２３を埋める埋め込み部３０ｃと、埋め込み部３０ｃと一体形成され、かつ層間絶縁膜２０上面よりも盛り上がった突出部３０ｂとが形成される。このように、埋め込み部３０ｃと突出部３０ｂとからなる光導波路３０が形成される。ここで、突出部３０ｂは、平面視した場合に、穴２３の開口よりも大きい平面形状を有する。 Next, as shown in FIG. 5A, for example, a resist pattern 31 for opening an upper portion of the optical waveguide material film 30a between the adjacent photoelectric conversion portions 11 is formed by a lithography process. Thereafter, an etching process such as RIE is performed using the resist pattern 31 as an etching mask. Thereby, the part which hits the upper part between the adjacent photoelectric conversion parts 11 in the optical waveguide material film 30a is removed. That is, in each hole 23 of the interlayer insulating film 20, a buried portion 30 c that fills each hole 23, and a protruding portion 30 b that is integrally formed with the buried portion 30 c and rises from the upper surface of the interlayer insulating film 20 are formed. In this manner, the optical waveguide 30 including the embedded portion 30c and the protruding portion 30b is formed. Here, the protrusion 30b has a larger planar shape than the opening of the hole 23 when viewed in plan.
　次に、図５Ｂに示すように、光導波路３０と、層間絶縁膜２０の露出している部分とを完全に被覆するように、ＣＶＤ法によりシリコン酸化膜からなる絶縁膜４０ａ（平坦化膜形成膜）を０．５μｍ程度堆積させる。これにより、層間絶縁膜２０と光導波路３０との表面段差を平坦に調整できる。 Next, as shown in FIG. 5B, an insulating film 40a (planarization film formation) made of a silicon oxide film is formed by CVD so as to completely cover the optical waveguide 30 and the exposed portion of the interlayer insulating film 20. Film) is deposited to about 0.5 μm. Thereby, the surface level difference between the interlayer insulating film 20 and the optical waveguide 30 can be adjusted to be flat.
　次に、図５Ｃに示すように、ＣＭＰ又はエッチバック等により、隣り合う光電変換部１１の間の上方に当たる部分の絶縁膜４０ａの表面の高さが突出部３０ｂ上面と同じ高さになるように平坦化処理する。これにより、平坦化膜４０が形成される。つまり、光導波路３０の突出部３０ｂの上面を露出するように平坦化処理が行われる。 Next, as shown in FIG. 5C, the height of the surface of the insulating film 40a at the upper portion between the adjacent photoelectric conversion portions 11 is made to be the same as the upper surface of the protruding portion 30b by CMP, etch back, or the like. To flatten. Thereby, the planarization film 40 is formed. That is, the flattening process is performed so that the upper surface of the protruding portion 30b of the optical waveguide 30 is exposed.
　次に、図５Ｄに示すように、光導波路３０及び平坦化膜４０の上に第３屈折率材料膜として、ＣＶＤ法等により前述したＴＥＯＳ材料等からなる絶縁膜５０ａ（隔壁形成膜）を形成する。絶縁膜５０ａの膜厚は０．７μｍ程度であり、後に形成するカラーフィルタ６０の膜厚と同程度である。 Next, as shown in FIG. 5D, an insulating film 50a (a partition wall forming film) made of the above-described TEOS material or the like is formed as a third refractive index material film on the optical waveguide 30 and the planarizing film 40 by the CVD method or the like. To do. The thickness of the insulating film 50a is about 0.7 μm, which is about the same as the thickness of the color filter 60 to be formed later.
　次に、図６Ａに示すように、絶縁膜５０ａ上に、下方の突出部３０ｂを取り囲むような形状のレジストパターン５１をリソグラフィ工程により形成する。 Next, as shown in FIG. 6A, a resist pattern 51 having a shape surrounding the lower protrusion 30b is formed on the insulating film 50a by a lithography process.
　次に、図６Ｂに示すように、レジストパターン５１を用いて、ＲＩＥなどのエッチング処理を実施する。これにより、第３屈折率材料膜からなる隔壁５０を形成する。隔壁５０の幅は０．２μｍ程度である。また、隔壁５０は、平面視した場合に光電変換部１１を取り囲むように形成される。 Next, as shown in FIG. 6B, an etching process such as RIE is performed using the resist pattern 51. Thus, the partition wall 50 made of the third refractive index material film is formed. The width of the partition 50 is about 0.2 μm. Moreover, the partition 50 is formed so as to surround the photoelectric conversion unit 11 when viewed in a plan view.
　次に、図６Ｃに示すように、隔壁５０で囲まれた領域にカラーフィルタ形成材料を埋め込むことでカラーフィルタ６０を形成する。 Next, as shown in FIG. 6C, a color filter 60 is formed by embedding a color filter forming material in a region surrounded by the partition walls 50.
　最後に、図６Ｄに示すように、マイクロレンズ７０を形成する。 Finally, as shown in FIG. 6D, a microlens 70 is formed.
　以上の工程により、図１に示す構成の固体撮像装置１００を製造することができる。 Through the above steps, the solid-state imaging device 100 having the configuration shown in FIG. 1 can be manufactured.
　（第２の実施形態）
　以下、本発明の第２の実施形態に係る固体撮像装置について、図面を参照しながら説明する。 (Second Embodiment)
Hereinafter, a solid-state imaging device according to a second embodiment of the present invention will be described with reference to the drawings.
　図７は、本発明の第２の実施形態に係る固体撮像装置２００の構成を示す断面図である。また、図７は、周辺画素の断面構造を示す。なお、中央画素の構成は第１の実施形態と同じである。 FIG. 7 is a cross-sectional view showing a configuration of a solid-state imaging device 200 according to the second embodiment of the present invention. FIG. 7 shows a cross-sectional structure of peripheral pixels. The configuration of the central pixel is the same as that in the first embodiment.
　図７に示すように、固体撮像装置２００では、第１の実施形態と同様に突出部３０ｂの中心位置が中央画素に近づく方向にずれている。さらに、固体撮像装置２００では、隔壁５０及びマイクロレンズ７０の中心位置が中央画素に近づく方向（撮像領域の中心方向側）にずれている。 As shown in FIG. 7, in the solid-state imaging device 200, the center position of the protrusion 30b is shifted in the direction approaching the center pixel, as in the first embodiment. Further, in the solid-state imaging device 200, the center positions of the partition wall 50 and the microlens 70 are shifted in the direction approaching the center pixel (the center direction side of the imaging region).
　ここで光電変換部１１の中心から突出部３０ｂの中心までの距離をａとし、光電変換部１１の中心からカラーフィルタ６０の中心までの距離をｂとし、光電変換部１１の中心からマイクロレンズ７０の中心までの距離をｃとするとａ≦ｂ≦ｃとなるように設定する。ここではａは穴２３の上端部の半径（埋め込み部３０ｃの上端部の半径）より小さく、ｃは突出部３０ｂの中央画素側よりの端部と光電変換部１１の中心との平面距離よりも小さく、ｂはａとｃとの中間程度に設定する。 Here, the distance from the center of the photoelectric conversion unit 11 to the center of the protrusion 30b is a, the distance from the center of the photoelectric conversion unit 11 to the center of the color filter 60 is b, and the center of the photoelectric conversion unit 11 to the microlens 70. If the distance to the center of c is c, a ≦ b ≦ c is set. Here, a is smaller than the radius of the upper end portion of the hole 23 (radius of the upper end portion of the embedded portion 30c), and c is larger than the planar distance between the end portion of the projecting portion 30b from the central pixel side and the center of the photoelectric conversion portion 11. It is small, and b is set to an intermediate level between a and c.
　このような構成により、周辺画素において、撮像領域の中央部から周辺方向へ斜めに入射する光を効率的に光導波路３０に導くことが可能となるので、固体撮像装置２００の感度が向上する。また、撮像装置の光学部材（レンズ）を通過した光は撮像領域の中央部の上方から周辺画素に照射される。従って、撮像領域の中心からの距離が大きくなるほど、外光が斜めに入射することになる。これに対して、固体撮像装置２００では、マイクロレンズ７０と、隔壁５０間のカラーフィルタ６０と、突出部３０ｂとの各中心位置を、その下方に位置する光電変換部１１の中心位置から撮像領域の中心に向かってずらす。さらに、そのずらし量をａ≦ｂ≦ｃとする。これにより、カラーフィルタ６０、及び光導波路３０に取り込まれる斜め光の光量を増加させることができる。結果として光電変換部１１の斜め光に対する感度を向上させることができる。ここで、ａ≦ｂ≦ｃを満たすのであれば、埋め込み部３０ｃの中心位置と突出部３０ｂの中心位置とカラーフィルタ６０の中心位置とを一致させた状態でマイクロレンズ７０のみをずらしてもよい。また、埋め込み部３０ｃの中心位置と突出部３０ｂの中心位置とを一致させた状態でマイクロレンズ７０とカラーフィルタ６０とをずらしてもよい。 Such a configuration makes it possible to efficiently guide light incident obliquely from the central portion of the imaging region to the peripheral direction to the optical waveguide 30 in the peripheral pixels, so that the sensitivity of the solid-state imaging device 200 is improved. In addition, the light that has passed through the optical member (lens) of the imaging device is irradiated to the peripheral pixels from above the central portion of the imaging region. Therefore, the greater the distance from the center of the imaging region, the more external light enters obliquely. On the other hand, in the solid-state imaging device 200, the center positions of the microlens 70, the color filter 60 between the partition walls 50, and the protruding portion 30b are changed from the center position of the photoelectric conversion unit 11 positioned below the imaging region. Move towards the center of the. Further, the shift amount is set to a ≦ b ≦ c. Thereby, the light quantity of the oblique light taken into the color filter 60 and the optical waveguide 30 can be increased. As a result, the sensitivity of the photoelectric conversion unit 11 to oblique light can be improved. Here, if a ≦ b ≦ c is satisfied, only the microlens 70 may be shifted in a state where the center position of the embedded portion 30 c, the center position of the protruding portion 30 b, and the center position of the color filter 60 are matched. . In addition, the microlens 70 and the color filter 60 may be shifted in a state where the center position of the embedded portion 30c and the center position of the protruding portion 30b are matched.
　例えば、周辺画素での光の入射角度が４°の場合、撮像領域の最外周に位置する画素セルの上記ａ、ｂ及びｃをそれぞれ、１２０ｎｍ、１６０ｎｍ及び２４０ｎｍ程度にすればよい。これにより、入射光がマイクロレンズ７０、カラーフィルタ６０、及び突出部３０ｂの中心を通って、埋め込み部３０ｃの中心に入射する。また、各画素セルのずらし量（ａ、ｂ、ｃ）は、最外周のずらし量を、中心画素から最外周の画素セルまでの画素数で割った値に、中心画素から対象の画素セルまでの画素数を掛けた値に設定すればよい。 For example, when the incident angle of light at the peripheral pixels is 4 °, the above-mentioned a, b, and c of the pixel cell located at the outermost periphery of the imaging region may be set to about 120 nm, 160 nm, and 240 nm, respectively. Thereby, incident light passes through the center of the microlens 70, the color filter 60, and the protrusion part 30b, and injects into the center of the embedding part 30c. The shift amount (a, b, c) of each pixel cell is obtained by dividing the shift amount of the outermost periphery by the number of pixels from the center pixel to the outermost pixel cell, from the center pixel to the target pixel cell. A value obtained by multiplying the number of pixels may be set.
　ここで、図７に示す光Ｌ２のように、周辺画素には、中央画素に比べて大きな角度で光が入射する。この光Ｌ２は、マイクロレンズ７０を透過後、カラーフィルタ６０を通過して隣接する画素セルのカラーフィルタ６０へ向かうような大きな角度で入射する。光Ｌ２は、隔壁５０に達するが、隔壁５０の屈折率がカラーフィルタ６０の屈折率より小さいことにより隔壁５０の表面で反射する。そして、反射した光が、再びカラーフィルタ６０を通り光導波路３０内部へと進行する。ここで、本実施形態では、突出部３０ｂに加えマイクロレンズ７０及び隔壁５０もずらしていることにより、第１の実施形態よりもさらに大きな角度の入射光を光導波路３０の内部へ集光することが可能となる。その結果、このような光が隣接する画素セルへ侵入することはないので、より混色を抑制することができる。さらに、このような光を光導波路３０に導くことが可能となるので、中央画素と周辺画素との感度差を低減することが可能となる。結果、固体撮像装置２００のシェーディング特性がさらに向上する。 Here, like the light L2 shown in FIG. 7, the light is incident on the peripheral pixels at a larger angle than the central pixel. After passing through the microlens 70, the light L2 passes through the color filter 60 and enters the color filter 60 of the adjacent pixel cell at a large angle. The light L <b> 2 reaches the partition 50, but is reflected on the surface of the partition 50 because the refractive index of the partition 50 is smaller than the refractive index of the color filter 60. Then, the reflected light travels again through the color filter 60 and into the optical waveguide 30. Here, in the present embodiment, the microlens 70 and the partition wall 50 are shifted in addition to the protruding portion 30b, so that incident light having a larger angle than that in the first embodiment is condensed into the optical waveguide 30. Is possible. As a result, since such light does not enter the adjacent pixel cell, color mixing can be further suppressed. Further, since such light can be guided to the optical waveguide 30, it is possible to reduce the sensitivity difference between the central pixel and the peripheral pixels. As a result, the shading characteristics of the solid-state imaging device 200 are further improved.
　なお、上記説明では、マイクロレンズ７０、カラーフィルタ６０、隔壁５０、及び突出部３０ｂの各中心位置を、その下方に位置する光電変換部１１の中心位置から撮像領域の中心に近づく方向にずらす場合を説明した。しかし、カメラなどが要求する光学特性に応じて、マイクロレンズ７０、カラーフィルタ６０、及び隔壁５０の各中心位置を、その下方に位置する光電変換部１１の中心位置を基準として撮像領域の中心から離れる方向にずらしてもよい。 In the above description, the center positions of the microlens 70, the color filter 60, the partition wall 50, and the protruding portion 30b are shifted from the center position of the photoelectric conversion unit 11 positioned below the center position of the imaging region. Explained. However, depending on the optical characteristics required by the camera or the like, the center positions of the microlens 70, the color filter 60, and the partition wall 50 are determined from the center of the imaging region with reference to the center position of the photoelectric conversion unit 11 located therebelow. You may shift in the direction to leave.
　なお、本実施形態に係る固体撮像装置２００は、図７に示した周辺画素のマイクロレンズ７０、隔壁５０、及び突出部３０ｂの平面位置のずれに特徴を有しており、その他は上述の第１の実施形態に係る固体撮像装置１００と同様である。また、本実施形態に係る固体撮像装置２００の製造方法は、上述の第１の実施形態に係る固体撮像装置１００の製造方法と基本的には同様なので説明は省略する。 Note that the solid-state imaging device 200 according to the present embodiment is characterized by the displacement of the planar positions of the microlenses 70, the partition walls 50, and the protrusions 30b of the peripheral pixels shown in FIG. This is the same as the solid-state imaging device 100 according to the first embodiment. In addition, the method for manufacturing the solid-state imaging device 200 according to the present embodiment is basically the same as the method for manufacturing the solid-state imaging device 100 according to the first embodiment described above, and a description thereof will be omitted.
　以上、本発明の実施形態に係る固体撮像装置について説明したが、本発明は、この実施形態に限定されるものではない。 The solid-state imaging device according to the embodiment of the present invention has been described above, but the present invention is not limited to this embodiment.
　また、上記実施形態に係る固体撮像装置は典型的には集積回路であるＬＳＩとして実現される。これらは個別に１チップ化されてもよいし、一部又は全てを含むように１チップ化されてもよい。 In addition, the solid-state imaging device according to the above embodiment is typically realized as an LSI that is an integrated circuit. These may be individually made into one chip, or may be made into one chip so as to include a part or all of them.
　また、上記各図において、各構成要素の角部及び辺を直線的に記載しているが、製造上の理由により、角部及び辺が丸みをおびたものも本発明に含まれる。 Further, in each of the above drawings, the corners and sides of each component are linearly described, but those having rounded corners and sides are also included in the present invention for manufacturing reasons.
　また、上記実施形態に係る固体撮像装置、及びその変形例の機能のうち少なくとも一部を組み合わせてもよい。 In addition, at least a part of the functions of the solid-state imaging device according to the above-described embodiment and its modifications may be combined.
　また、上記で用いた数字は、全て本発明を具体的に説明するために例示するものであり、本発明は例示された数字に制限されない。また、上記で示した各構成要素の材料は、全て本発明を具体的に説明するために例示するものであり、本発明は例示された材料に制限されない。 Further, all the numbers used above are illustrated for specifically explaining the present invention, and the present invention is not limited to the illustrated numbers. Further, the materials of the constituent elements shown above are all exemplified for specifically explaining the present invention, and the present invention is not limited to the exemplified materials.
　更に、本発明の主旨を逸脱しない限り、本実施形態に対して当業者が思いつく範囲内の変更を施した各種変形例も本発明に含まれる。 Furthermore, various modifications in which the present embodiment is modified within the scope conceived by those skilled in the art are also included in the present invention without departing from the gist of the present invention.
　本発明は、固体撮像装置に適用できる。また、本発明は、固体撮像装置を用いるデジタルスチルカメラ及びデジタルビデオカメラ等の各種撮像装置に適用できる。 The present invention can be applied to a solid-state imaging device. In addition, the present invention can be applied to various imaging devices such as a digital still camera and a digital video camera using a solid-state imaging device.
　１０、１０１　半導体基板
　１１　光電変換部
　２０　層間絶縁膜
　２０ａ　積層体膜
　２０ｃ　上面
　２１、２１ａ、２１ｂ　配線層
　２２、３１、５１　レジストパターン
　２３　穴
　３０、１０５ａ　光導波路
　３０ａ　光導波路材料膜
　３０ｂ　突出部
　３０ｃ　埋め込み部
　４０　平坦化膜
　４０ａ、５０ａ　絶縁膜
　５０　隔壁
　６０　カラーフィルタ
　７０、１０９　マイクロレンズ
　１００、２００、３００　固体撮像装置
　１０２　受光部
　１０３　絶縁層
　１１２　透光性材料 DESCRIPTION OF SYMBOLS 10,101 Semiconductor substrate 11 Photoelectric conversion part 20 Interlayer insulation film 20a Laminated body film 20c Upper surface 21, 21a, 21b Wiring layer 22, 31, 51 Resist pattern 23 Hole 30, 105a Optical waveguide 30a Optical waveguide material film 30b Protrusion part 30c Embedding Part 40 Planarization film 40a, 50a Insulating film 50 Partition wall 60 Color filter 70, 109 Micro lens 100, 200, 300 Solid-state imaging device 102 Light receiving part 103 Insulating layer 112 Translucent material

Claims (17)

  1. 　半導体基板と、
    　前記半導体基板に行列状に形成された複数の光電変換部と、
    　前記半導体基板の上に形成された層間絶縁膜と、
    　前記複数の光電変換部それぞれの上方に形成された光導波路と、
    　複数の前記光導波路それぞれの上方に形成されたカラーフィルタと、
    　隣接する前記カラーフィルタを分離する隔壁とを備え、
    　前記複数の光導波路のそれぞれは、前記層間絶縁膜中に埋め込まれた埋め込み部と、前記層間絶縁膜から突出して形成された突出部とを含み、
    　前記突出部は、前記埋め込み部の上面、及び平面視したときに前記層間絶縁膜における前記埋め込み部の周囲を被覆する
    　固体撮像装置。     A semiconductor substrate;
    A plurality of photoelectric conversion portions formed in a matrix on the semiconductor substrate;
    An interlayer insulating film formed on the semiconductor substrate;
    An optical waveguide formed above each of the plurality of photoelectric conversion units;
    A color filter formed above each of the plurality of optical waveguides;
    A partition that separates adjacent color filters;
    Each of the plurality of optical waveguides includes an embedded portion embedded in the interlayer insulating film, and a protruding portion formed protruding from the interlayer insulating film,
    The protruding portion covers the upper surface of the embedded portion and the periphery of the embedded portion in the interlayer insulating film when viewed in plan.
  2. 　前記固体撮像装置は、さらに、
    　隣接する前記突出部を分離する平坦化膜を備える
    　請求項１に記載の固体撮像装置。     The solid-state imaging device further includes:
    The solid-state imaging device according to claim 1, further comprising a planarization film that separates adjacent protrusions.
  3. 　前記突出部は、平面視したときに１画素セルに対応する前記隔壁に囲まれた領域内に収まる形状である
    　請求項１又は２に記載の固体撮像装置。     The solid-state imaging device according to claim 1, wherein the protruding portion has a shape that fits in a region surrounded by the partition corresponding to one pixel cell when viewed in plan.
  4. 　前記埋め込み部と前記突出部とは同一の材料で形成されている
    　請求項１～３のいずれか１項に記載の固体撮像装置。     The solid-state imaging device according to any one of claims 1 to 3, wherein the embedded portion and the protruding portion are formed of the same material.
  5. 　前記突出部の上面は、前記平坦化膜から露出している
    　請求項２に記載の固体撮像装置。     The solid-state imaging device according to claim 2, wherein an upper surface of the protruding portion is exposed from the planarization film.
  6. 　前記複数の光電変換部が形成されている撮像領域は、中央部と、前記中央部より外側に位置する周辺部とを含み、
    　前記中央部に配置されている中央画素において、平面視した場合の前記埋め込み部の中心位置と前記突出部の中心位置とが一致しており、
    　前記周辺部に配置されている周辺画素において、平面視した場合の前記突出部の中心位置が前記埋め込み部の中心位置に対して前記撮像領域の中央方向側にある
    　請求項１～５のいずれか１項に記載の固体撮像装置。     The imaging region in which the plurality of photoelectric conversion units are formed includes a central part and a peripheral part located outside the central part,
    In the central pixel disposed in the central portion, the center position of the embedded portion and the center position of the protruding portion when viewed in plan match,
    6. The peripheral pixel arranged in the peripheral portion has a center position of the projecting portion in a plan view located on a center direction side of the imaging region with respect to a center position of the embedded portion. The solid-state imaging device according to item 1.
  7. 　前記固体撮像装置は、さらに、
    　複数の前記カラーフィルタそれぞれの上方に形成されたマイクロレンズを備え、
    　前記周辺画素において、平面視した場合の前記隔壁の中心位置と、前記マイクロレンズの中心位置とが前記埋め込み部の中心位置に対して前記撮像領域の中央方向側にある
    　請求項６に記載の固体撮像装置。     The solid-state imaging device further includes:
    A microlens formed above each of the plurality of color filters;
    7. The solid according to claim 6, wherein a center position of the partition wall and a center position of the microlens in a plan view of the peripheral pixel are on a center direction side of the imaging region with respect to a center position of the embedded portion. Imaging device.
  8. 　前記周辺画素における、前記埋め込み部の中心位置と前記突出部の中心位置との第１のズレ量と、前記埋め込み部の中心位置と前記隔壁の中心位置との第２のズレ量と、前記埋め込み部の中心位置と前記マイクロレンズの中心位置との第３のズレ量とは、第１のズレ量≦第２のズレ量≦第３のズレ量の関係を満たす
    　請求項７に記載の固体撮像装置。     In the peripheral pixel, a first shift amount between the center position of the embedded portion and the center position of the protruding portion, a second shift amount between the center position of the embedded portion and the center position of the partition wall, and the embedded pixel 8. The solid-state imaging according to claim 7, wherein the third displacement amount between the center position of the portion and the center position of the microlens satisfies the relationship of the first displacement amount ≦ the second displacement amount ≦ the third displacement amount. apparatus.
  9. 　前記第１のズレ量は、前記埋め込み部の上端部の半径よりも小さく、
    　前記第３のズレ量は、前記突出部の前記撮像領域の中央方向側の端部と前記光電変換部の中心位置との平面距離よりも小さい
    　請求項８に記載の固体撮像装置。     The first shift amount is smaller than the radius of the upper end portion of the embedded portion,
    The solid-state imaging device according to claim 8, wherein the third deviation amount is smaller than a planar distance between an end portion of the projecting portion on the central direction side of the imaging region and a center position of the photoelectric conversion unit.
  10. 　前記突出部の断面形状は、方形、台錐形、又はレンズ状形である
    　請求項１～９のいずれか１項に記載の固体撮像装置。     The solid-state imaging device according to any one of claims 1 to 9, wherein a cross-sectional shape of the protruding portion is a square shape, a trapezoidal shape, or a lens shape.
  11. 　前記突出部の平面形状は、正方形、長方形、多角形、円形、又は楕円形である
    　請求項１～１０のいずれか１項に記載の固体撮像装置。     The solid-state imaging device according to any one of claims 1 to 10, wherein a planar shape of the protruding portion is a square, a rectangle, a polygon, a circle, or an ellipse.
  12. 　前記光導波路の屈折率は、前記平坦化膜の屈折率よりも大きく、
    　前記カラーフィルタの屈折率は、前記隔壁の屈折率よりも大きい
    　請求項２に記載の固体撮像装置。     The refractive index of the optical waveguide is larger than the refractive index of the planarization film,
    The solid-state imaging device according to claim 2, wherein a refractive index of the color filter is larger than a refractive index of the partition wall.
  13. 　前記固体撮像装置は、さらに、前記層間絶縁膜に形成された配線を備え、
    　平面視した場合に前記突出部の一部は前記配線と重なる
    　請求項１～１２のいずれか１項に記載の固体撮像装置。     The solid-state imaging device further includes a wiring formed in the interlayer insulating film,
    The solid-state imaging device according to any one of claims 1 to 12, wherein a part of the protruding portion overlaps the wiring in a plan view.
  14. 　半導体基板に行列状に複数の光電変換部を形成する工程と、
    　前記半導体基板の上に層間絶縁膜を形成する工程と、
    　前記層間絶縁膜の前記複数の光電変換部それぞれの上方に穴を形成する工程と、
    　前記穴に埋め込まれた埋め込み部と、前記埋め込み部の上面、及び平面視したときに前記層間絶縁膜における前記埋め込み部の周囲を被覆し、かつ、前記層間絶縁膜から突出して形成された突出部とを含む光導波路を形成する工程と、
    　隣接する前記突出部を分離する平坦化膜を形成する工程と、
    　複数の前記光導波路それぞれの上方にカラーフィルタを形成する工程と、
    　前記平坦化膜の上方に、隣接する前記カラーフィルタを分離する隔壁を形成する工程とを含む
    　固体撮像装置の製造方法。     Forming a plurality of photoelectric conversion portions in a matrix on a semiconductor substrate;
    Forming an interlayer insulating film on the semiconductor substrate;
    Forming a hole above each of the plurality of photoelectric conversion portions of the interlayer insulating film;
    An embedded portion embedded in the hole, an upper surface of the embedded portion, and a projecting portion that covers the periphery of the embedded portion in the interlayer insulating film when viewed in plan, and protrudes from the interlayer insulating film Forming an optical waveguide including:
    Forming a planarization film for separating adjacent protrusions;
    Forming a color filter above each of the plurality of optical waveguides;
    Forming a partition for separating the adjacent color filters above the planarizing film. A method for manufacturing a solid-state imaging device.
  15. 　前記光導波路を形成する工程は、
    　前記層間絶縁膜の上方に光導波路形成膜を形成する工程と、
    　前記光導波路形成膜上における前記穴の上方にレジストパターンを形成する工程と、
    　前記レジストパターンをエッチングマスクとして用いて、平面視した場合に、前記穴の開口よりも大きな前記突出部を形成する工程とを含む
    　請求項１４に記載の固体撮像装置の製造方法。     The step of forming the optical waveguide includes:
    Forming an optical waveguide forming film above the interlayer insulating film;
    Forming a resist pattern above the hole on the optical waveguide forming film;
    The method of manufacturing a solid-state imaging device according to claim 14, further comprising: forming the protruding portion larger than the opening of the hole when viewed in plan using the resist pattern as an etching mask.
  16. 　前記平坦化膜を形成する工程は、
    　前記層間絶縁膜及び前記光導波路を被覆する平坦化膜形成膜を形成する工程と、
    　ＣＭＰ（Ｃｈｅｍｉｃａｌ　Ｍｅｃｈａｎｉｃａｌ　Ｐｏｌｉｓｈｉｎｇ）又はエッチバックを用いて、前記平坦化膜形成膜から前記突出部の上面を露出させる工程とを含む
    　請求項１４又は１５に記載の固体撮像装置の製造方法。     The step of forming the planarizing film includes:
    Forming a planarization film forming film covering the interlayer insulating film and the optical waveguide;
    The method of manufacturing a solid-state imaging device according to claim 14, further comprising: exposing an upper surface of the projecting portion from the planarization film forming film using CMP (Chemical Mechanical Polishing) or etch back.
  17. 　前記隔壁を形成する工程は、
    　前記平坦化膜上に隔壁形成膜を形成する工程と、
    　前記隔壁形成膜をエッチングすることで、平面視した場合に前記光電変換部を取り囲む前記隔壁を形成する工程とを含み、
    　前記カラーフィルタを形成する工程では、前記隔壁で囲まれた領域に前記カラーフィルタ形成材料を埋め込むことで前記カラーフィルタを形成する
    　請求項１４～１６のいずれか１項に記載の固体撮像装置の製造方法。     The step of forming the partition includes
    Forming a partition wall forming film on the planarizing film;
    Etching the partition forming film, and forming the partition surrounding the photoelectric conversion part when viewed in plan,
    The solid-state imaging device manufacturing method according to any one of claims 14 to 16, wherein, in the step of forming the color filter, the color filter is formed by embedding the color filter forming material in a region surrounded by the partition wall. Method.
PCT/JP2012/005319 2011-09-06 2012-08-24 Solid-state image capture device and method of manufacturing same WO2013035258A1 (en)

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