JP2010272612A - Solid-state imaging device, method of manufacturing the same, and imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress degradation of sensitivity due to an antireflection structure to reversely increase sensitivity, and to suppress shading to suppress occurrence of noise such as a flare or ghost. <P>SOLUTION: This solid-state imaging device includes, on a semiconductor substrate 11, a photoelectric conversion part 12 for subjecting incident light to photoelectric conversion to obtain signal charge, and a plurality of layers of optically-transparent films formed on the photoelectric conversion part 12. In the solid-state imaging device, the antireflection structure 31 is formed on a surface of the semiconductor substrate 11 or a surface of a passivation film 22 of at least one layer out of the plurality of layers of optically-transparent films; the antireflection structure 31 includes fusiform projective bodies 32 arranged on the surface of the passivation film 22, having optical transparency and each having a sinusoidal curve; and the height of the projective body 32 is 50-100 nm when the pitch of the arrangement is 40 nm, 200-400 nm when the pitch of the arrangement is 100 nm, and 50-400 nm when the pitch of the arrangement is 200 nm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device, a manufacturing method thereof, and an imaging device.

In the solid-state imaging device, a condensing laminated structure for efficiently collecting light is formed. In this case, since different materials are laminated, an interface having a large refractive index variation is present, so that light loss occurs due to reflection at the interface, and this leads to a decrease in sensitivity. The light reflected from the interface also causes noise such as flare and ghost.
On the other hand, a method has been proposed in which an antireflection film is formed on an interface having a large refractive index difference to reduce interface reflection (see, for example, Patent Documents 1 and 2).
Further, as a higher-performance antireflection structure, a method of reducing interface reflection by forming a fine concavo-convex structure on an on-chip lens has been proposed (see, for example, Patent Documents 3, 4, and 5). .

In the case of a method of forming an antireflection film on an interface having a large refractive index difference and reducing interface reflection (for example, Patent Documents 1 and 2), a film in which the phase of light is reversed due to the antireflection structure of a single layer film By forming the thickness, the antireflection performance is enhanced.
However, in actual manufacturing of a solid-state imaging device, there is a step between the light receiving element portion and the peripheral circuit, and it is difficult to form a uniform single layer film on the light receiving device. Therefore, the interference state for each location of the light receiving element is different. In general, the optimum film thickness of the antireflection film varies depending on the wavelength of visible light, which causes color unevenness.
For these reasons, antireflection with a single-layer film in a solid-state imaging device has drawbacks both in manufacturing and in principle.

As a more detailed explanation, FIG. 17 shows the state of interference fringes due to reflection when a silicon nitride film is formed as an antireflection film with respect to the interface between silicon and air (interface on the silicon side).
The thickness of the antireflection film is optimized to a wavelength of 560 nm in visible light. Therefore, it can be seen that interference fringes with light having a wavelength of 560 nm almost disappear and function as an antireflection film. On the other hand, interference fringes are not reduced so much in the case of light having a wavelength of 440 nm. As described above, the interference reduction effect by the antireflection film varies depending on the wavelength of the incident light. For this reason, the sensitivity variation of the incident light with respect to the variation of the film thickness of the antireflection film varies, and this causes color unevenness.

The solid-state imaging device disclosed in Patent Document 3 has an antireflection structure in which a fine concavo-convex structure is formed on the surface of a passivation film, and has a period of 0.05 μm to 1 μm as a feature of the fine concavo-convex structure. Has an aspect ratio of. In the study by the present inventor, it has been confirmed that when a fine uneven structure exceeding a certain aspect ratio is formed, the sensitivity is lowered. This is considered to be caused by an increase in the optical path length for light collection due to an increase in the aspect ratio of the fine concavo-convex structure.
In the forming method disclosed in Patent Document 3, a pattern with one side of 100 nm is patterned by electron beam lithography so that a space with an adjacent pattern is 100 nm. Thereafter, reactive ion etching (RIE) is performed to form a pattern of fine protrusions. In this formation method, for example, if the pattern of the fine protrusions is arranged on a light receiving element having a pitch of 2.0 μm, 400 fine protrusion patterns are required per light receiving element.
In recent years, the number of light receiving elements exceeding one million per chip is the mainstream, and in this case, a pattern of 400 million fine protrusions per chip is required. When this is to be formed by electron beam lithography, if the drawing time per pattern of fine protrusions is 100 nsec, it takes 11 hours or more per 300 mm wafer, which is not practical.

  In addition, the concavo-convex structure disclosed in Patent Document 4 is manufactured by using lithography with a concavo-convex structure having a height of 100 to 5000 mm at a pitch that does not diffract incident light. However, there is no specific disclosure about a manufacturing method using lithography.

In Patent Document 5, as a feature of the concavo-convex structure unit, 0.1λ <pitch <0.8λ, 0.5λ <height <5λ (λ is the wavelength of incident light).
However, for example, when pitch = 0.11λ and height = 4.4λ, the aspect ratio is 40, and as described above, the sensitivity is lowered. Further, it is not practical in terms of preventing shading (a phenomenon in which the light condensing characteristics of the pixels arranged on the end side of the light receiving region where the oblique incidence is performed deteriorates with respect to the pixels arranged at the center of the optical axis).
Moreover, although it is disclosed that it can be manufactured using a nanoimprint method, when manufacturing a concavo-convex structure unit having a large aspect ratio (that is, a high structure height), the protrusion is difficult to be separated from the mold, This is not realistic because it causes a problem in peelability.

JP 2007-242697 A Japanese Patent Laid-Open No. 06-292206 JP 2004-47682 A JP 2006-147991 A International Publication No. WO2005 / 109042

  The problem to be solved is that when a fine concavo-convex structure exceeding a certain aspect ratio is formed, the sensitivity is lowered. Further, if the aspect ratio is too large, it is difficult to form a fine projection pattern by a nanoimprint method in terms of mold releasability.

  The present invention suppresses a decrease in sensitivity due to the formation of the antireflection structure, and conversely, makes it possible to increase sensitivity and suppress shading, thereby preventing reflection. In addition, it is possible to manufacture an antireflection structure by a nanoimprint method.

  A solid-state imaging device of the present invention includes a photoelectric conversion unit that photoelectrically converts incident light into a semiconductor region to obtain a signal charge, and a plurality of light-transmitting films formed on the photoelectric conversion unit. An antireflection structure is formed on the surface of the first light transmissive film of at least one layer of the light transmissive film or the surface of the semiconductor region, and the antireflection structure is formed on the surface of the first light transmissive film or It consists of spindle-shaped projections having light transmittance and a sinusoidal curved surface arranged on the surface of the semiconductor region, and the projections have a height of 50 nm or more and 100 nm or less when the arrangement pitch is 40 nm. When the pitch is 100 nm, the height is 200 nm or more and 400 nm or less, and when the arrangement pitch is 200 nm, the height is 50 nm or more and 400 nm or less.

  In the solid-state imaging device of the present invention, since the antireflection structure is composed of spindle-shaped protrusions having a light-transmitting and sinusoidal curved surface arranged on the entire surface, the volume of the substance on both sides of the interface of the antireflection structure Change changes linearly. For this reason, when the lateral size of the protrusion is smaller than the wavelength of light, the space occupancy of one substance at the interface gradually changes, and the effective refractive index is continuously changed by switching to the other substance. Change. The change in the space occupancy has the same meaning as the change in the volume of the substance on both sides of the interface, so that the change in the refractive index in the antireflection structure is linear, and the reflection of light is reduced. In addition, the protrusions have a height of 50 nm to 100 nm when the arrangement pitch is 40 nm, the height is 200 nm to 400 nm when the arrangement pitch is 100 nm, and the arrangement pitch is 200 nm. The height is 50 nm or more and 400 nm or less. Due to such a limitation, the aspect ratio of the protrusions is not increased, and a decrease in sensitivity is suppressed.

  In the manufacturing method (first manufacturing method) of the solid-state imaging device of the present invention, when the light-transmitting film having a plurality of layers is formed on the photoelectric conversion unit that photoelectrically converts incident light into the semiconductor region and obtains signal charges, A step of forming an antireflection structure on the surface of at least one first light transmissive film of the plurality of light transmissive films, wherein the step of forming the antireflection structure includes the first light transmissive film. A step of forming an ultraviolet curable film on the surface, and an ultraviolet transmissive nanoimprint mold in which spindle-shaped concave portions having a sinusoidal surface are arranged on the entire surface are pressed against the ultraviolet curable film, thereby forming a spindle-shaped concave portion having a sinusoidal curved surface. Transferring the shape of the film to the surface of the ultraviolet curable film, irradiating the ultraviolet curable film with ultraviolet rays while pressing the nanoimprint mold, and curing the nanoimprint from the ultraviolet curable film. A step of removing the mold, and etching back the upper portion of the ultraviolet curable film and the first light transmissive film to form a spindle-shaped protrusion having a sinusoidal curved surface formed on the ultraviolet curable film. A step of transferring to the surface of the light-transmitting film, wherein the protrusion is formed to have a height of 50 nm to 100 nm when the arrangement pitch is 40 nm, and when the arrangement pitch is 100 nm, the height is 200 nm or more. When the pitch is 200 nm or less and the arrangement pitch is 200 nm, the height is 50 nm or more and 400 nm or less.

  In the first manufacturing method of the present invention, since the protrusion of the antireflection structure is formed into a spindle shape having a sinusoidal curved surface, the volume change of the substance on both sides of the interface of the antireflection structure changes linearly. . For this reason, when the lateral size of the protrusion is smaller than the wavelength of light, the space occupancy of one substance at the interface gradually changes, and the effective refractive index is continuously changed by switching to the other substance. Will change. Therefore, the refractive index change in the antireflection structure is linear, and the reflection of light is reduced. In addition, the protrusions have a height of 50 nm to 100 nm when the arrangement pitch is 40 nm, the height is 200 nm to 400 nm when the arrangement pitch is 100 nm, and the arrangement pitch is 200 nm. The height is 50 nm or more and 400 nm or less. Due to such restrictions, the aspect ratio of the protrusions does not increase and is 4 at the maximum, so that a decrease in sensitivity is suppressed and the nanoimprint method can be adopted.

  When the solid-state imaging device manufacturing method (second manufacturing method) of the present invention forms a plurality of light-transmitting films on a photoelectric conversion unit that photoelectrically converts incident light into a semiconductor region to obtain a signal charge, A step of forming an antireflection structure on the surface of at least one first light transmissive film of the plurality of light transmissive films, wherein the step of forming the antireflection structure includes the first light transmissive film. Forming a UV-curable nanoimprint mold having a spindle-shaped concave portion having a sinusoidal curved surface all over the first light-transmitting film. , Transferring the shape of the spindle-shaped concave portion having a sinusoidal curved surface to the surface of the first light transmissive film, and irradiating the first light transmissive film with ultraviolet rays while pressing the nanoimprint mold. Curing and the first light A step of removing the nanoimprint mold from the transient film, wherein the protrusion is formed to have a height of 50 nm or more and 100 nm or less when the arrangement pitch is 40 nm, and when the arrangement pitch is 100 nm, the height is 200 nm. When the pitch is not less than 400 nm and the arrangement pitch is 200 nm, the height is not less than 50 nm and not more than 400 nm.

  In the second manufacturing method of the present invention, since the protrusion of the antireflection structure is formed into a spindle shape having a sinusoidal curved surface, the volume change of the substance on both sides of the interface of the antireflection structure changes linearly. . For this reason, when the lateral size of the protrusion is smaller than the wavelength of light, the space occupancy of one substance at the interface gradually changes, and the effective refractive index is continuously changed by switching to the other substance. Will change. Therefore, the refractive index change in the antireflection structure is linear, and the reflection of light is reduced. In addition, the protrusions have a height of 50 nm to 100 nm when the arrangement pitch is 40 nm, the height is 200 nm to 400 nm when the arrangement pitch is 100 nm, and the arrangement pitch is 200 nm. The height is 50 nm or more and 400 nm or less. Due to such limitations, the aspect ratio of the protrusions does not increase and is 4 at the maximum, so that a decrease in sensitivity is suppressed and the nanoimprint method can be employed.

  An imaging apparatus according to the present invention includes a condensing optical unit that condenses incident light, an imaging unit that includes a solid-state imaging device that receives and photoelectrically converts the light collected by the condensing optical unit, and a photoelectrically converted signal. The solid-state imaging device includes a photoelectric conversion unit that photoelectrically converts incident light into a semiconductor region to obtain a signal charge, and a plurality of layers of light transmittance formed on the photoelectric conversion unit. An antireflection structure is formed on the surface of at least one first light transmissive film or the surface of the semiconductor region of the plurality of light transmissive films, and the antireflection structure includes: A spindle-shaped protrusion having a light transmission and a sinusoidal curved surface arranged on the surface of the first light-transmitting film or the semiconductor region, and the spindle-shaped protrusion has an arrangement pitch of 40 nm. The height is not less than 50 nm and not more than 100 nm. If pitch is 100nm, the height is at 200nm than 400nm or less, if the pitch of the array is 200nm, is 50nm or more 400nm or less height.

  In the imaging device of the present invention, since the solid-state imaging device of the present invention is used for the solid-state imaging device of the imaging unit, a decrease in sensitivity is suppressed.

  The solid-state imaging device of the present invention can prevent a decrease in sensitivity of the entire pixel, can prevent shading, and can prevent reflection. Therefore, since noise such as flare and ghost can be reduced, there is an advantage that a high-quality image with high sensitivity can be obtained.

  Since the solid-state imaging device manufacturing method of the present invention can employ the nanoimprint method, it is possible to obtain a high-sensitivity and high-quality image with reduced noise such as flare and ghost at low cost. There is an advantage that can be manufactured.

  The imaging apparatus of the present invention has an advantage that a high-sensitivity and high-quality image can be obtained because the solid-state imaging apparatus capable of obtaining a high-sensitivity and high-quality image of the present invention is used.

1 is a schematic cross-sectional view illustrating an example of the configuration of a solid-state imaging device according to a first embodiment of the present invention. It is the elements on larger scale of FIG. It is a relationship diagram of the sensitivity ratio and the sensitivity variation ratio with respect to the height of the protrusions when the protrusion pitch is 40 nm. It is a relationship diagram of the sensitivity ratio and the sensitivity variation ratio with respect to the height of the protrusions when the protrusion pitch is 100 nm. It is a relationship diagram of the sensitivity ratio and the sensitivity variation ratio with respect to the height of the protrusions when the protrusion pitch is 200 nm. It is a relationship diagram of the sensitivity ratio and the sensitivity variation ratio with respect to the height of the protrusions when the protrusion pitch is 400 nm. FIG. 6 is a relationship diagram between sensitivity variation ratio and projection pitch when the aspect ratio of the projection is 1. FIG. It is schematic structure sectional drawing which showed the 1st example of the manufacturing method of the solid-state imaging device which concerns on 2nd Embodiment of this invention. It is schematic structure sectional drawing which showed the 1st example of the manufacturing method of the solid-state imaging device which concerns on 2nd Embodiment of this invention. It is schematic structure sectional drawing which showed the 1st example of the manufacturing method of the solid-state imaging device which concerns on 2nd Embodiment of this invention. It is schematic structure sectional drawing which showed the 1st example of the manufacturing method of the solid-state imaging device which concerns on 2nd Embodiment of this invention. It is schematic structure sectional drawing which showed the 1st example of the manufacturing method of the solid-state imaging device which concerns on 2nd Embodiment of this invention. It is schematic structure sectional drawing which showed the 2nd example of the manufacturing method of the solid-state imaging device which concerns on 2nd Embodiment of this invention. It is schematic structure sectional drawing which showed the 2nd example of the manufacturing method of the solid-state imaging device which concerns on 2nd Embodiment of this invention. It is schematic structure sectional drawing which showed the 2nd example of the manufacturing method of the solid-state imaging device which concerns on 2nd Embodiment of this invention. It is the block diagram which showed an example of the structure of the imaging device which concerns on 3rd Embodiment of this invention. It is the figure which showed the interference fringe by reflection at the time of forming the silicon nitride film of an antireflection film in the interface of silicon and air.

  Hereinafter, modes for carrying out the invention (hereinafter referred to as embodiments) will be described.

<1. First Embodiment>
[Example of configuration of solid-state imaging device]
An example of the configuration of the solid-state imaging device according to the first embodiment of the present invention will be described with reference to the schematic configuration cross-sectional view of FIG. 1 and the partially enlarged view of FIG.

As shown in FIG. 1, a photoelectric conversion unit 12 that converts incident light into signal charges is formed on a semiconductor substrate (semiconductor region) 11. For example, a silicon substrate is used as the semiconductor substrate 11. The semiconductor substrate 11 is formed with a vertical charge transfer unit 13 that reads and transfers signal charges from the photoelectric conversion unit 12. A transfer gate 15 is formed on the vertical charge transfer portion 13 of the semiconductor substrate 11 via a gate insulating film 14. Further, the transfer gate 15 is covered with a light shielding film 17 via an insulating film 16. The insulating film 16 may have a function of an antireflection film made of an inorganic material having light permeability, for example.
An opening 18 is provided on the photoelectric conversion unit 12 of the light shielding film 17.
Further, a plurality of light transmissive films are formed on the semiconductor substrate 11 so as to cover the photoelectric conversion unit 12, the light shielding film 17, and the like. For example, an interlayer insulating film 21 is formed. The interlayer insulating film 21 is formed of, for example, a silicon oxide-based insulating film, and is formed of, for example, a boron phosphorus silicate glass (BPSG) film. Of course, it may be formed of another silicon oxide insulating film.
Further, a passivation film 22 is formed. For example, the passivation film 22 is formed of, for example, a plasma CVD silicon nitride (P-SiN) film. The surface of the passivation film 22 is planarized by, for example, a chemical mechanical polishing method.
A planarizing film 23 is formed on the surface of the passivation film 22. The planarizing film 23 is formed of, for example, an organic film or an inorganic film having light transmittance.

An antireflection structure 31 is formed on the surface of the passivation film 22, which is one layer of the plurality of light transmissive films.
The antireflection structure 31 includes spindle-shaped protrusions 32 having light transmittance and a sinusoidal curved surface arranged vertically and horizontally on the surface of the passivation film 22.
As shown in FIG. 2, the protrusions 32 formed on the entire surface of the passivation film 22 have a height h ₀ of 50 nm or more and 100 nm or less when the arrangement pitch p is 40 nm. When the arrangement pitch p is 100 nm, the height h ₀ is 200 nm or more and 400 nm or less. Further, when the arrangement pitch p is 200 nm, the height h ₀ is 50 nm or more and 400 nm or less.

The protrusion 32 has a spindle shape having a sinusoidal curved surface for the following reason.
That is, since the reflection of light is caused by a sudden change in the refractive index, by forming a structure in which the refractive index is continuously distributed at the interface of different substances by the fine protrusion pattern such as the protrusion 32, Light reflection can be reduced. When the lateral size of the protrusion 32 is smaller than the wavelength of light, the space occupancy of one material (for example, the planarization film 23) at the interface gradually changes, and the other material (for example, The effective refractive index changes continuously by switching to the passivation film 22). Since the change in the space occupancy has the same meaning as the change in volume of the substance on both sides of the interface, a spindle-shaped antireflection structure having a sinusoidal surface with a smooth volume change is suitable. In other words, the protrusion 32 has a volume change in the height direction of the protrusion 32 that decreases linearly from the bottom to the top of the protrusion 32.

  Further, as shown in FIG. 1, a color filter layer 41 is formed on the planarizing film 23, and a micro lens 42 that guides incident light to the photoelectric conversion unit 12 is formed. The color filter layer 41 includes, for example, a red color filter layer R, a green color filter layer G, and a blue color filter layer B corresponding to each photoelectric conversion unit 12. Of course, a color filter layer having a color other than those described above, for example, a complementary color filter layer may be used. For example, in the case of a solid-state imaging device that obtains a monochrome image, the color filter layer is not necessarily formed.

  The solid-state imaging device 1 is configured as described above.

Here, the pitch and height of the protrusion 32 will be described.
As shown in FIG. 3, the protrusion 32 has a height h ₀ at which the sensitivity ratio is 100% or more and the sensitivity variation ratio is 60% or less when the arrangement pitch p is 40 nm. It was found that the height h ₀ to be 50 nm or more and 150 nm or less. Therefore, when the arrangement pitch p is 40 nm, the height h ₀ is set to 50 nm to 100 nm. In this embodiment, the sensitivity variation ratio is set to less than 60%, but this value may be appropriately determined depending on each product or process.

Here, the sensitivity ratio was averaged in the range of the production variation ability of the passivation film 22, and the ratio when the state without the uneven structure was 100% was plotted. Similarly, for the sensitivity variation ratio, the sensitivity range in the production variation of the passivation film 22 is divided by the sensitivity at that level, and the state without the uneven structure is defined as 100%, and the improvement rate is plotted. The sensitivity variation ratio indicates the performance of the concavo-convex structure because the interface reflection is reduced by application of the concavo-convex structure and means the fluctuation range of the sensitivity to the film thickness variation. The wavelength used for the evaluation was 440 nm. This is because the pitch required for the concavo-convex structure is said to be below the wavelength, so by using 440 nm on the short wavelength side of visible light, the concavo-convex structure optimized there is also on the long wavelength side. It is because it is obvious that there is an effect.
Hereinafter, the sensitivity ratio and the sensitivity variation ratio are based on the above definitions.

As shown in FIG. 4, the protrusion 32 has a sensitivity ratio of 100% or more when the arrangement pitch p is 100 nm. The height h ₀ is 50 nm or more and 400 nm or less, and the sensitivity variation ratio is 60% or less. It was found that the height h ₀ to be 200 nm or more and 400 nm or less. Therefore, when the arrangement pitch p is 100 nm, the height h ₀ is set to 200 nm or more and 400 nm or less.

As shown in FIG. 5, the protrusion 32 has a sensitivity ratio of 100% or more when the arrangement pitch p is 200 nm. The height h ₀ is 50 nm or more and 400 nm or less, and the sensitivity variation ratio is 60% or less. It was found that the height h ₀ to be 50 nm or more and 800 nm or less. Therefore, when the arrangement pitch p is 100 nm, the height h ₀ is set to 50 nm or more and 400 nm or less.

Furthermore, as shown in FIG. 6, the protrusion 32 has a height h ₀ at which the sensitivity ratio is 100% or more and the sensitivity variation ratio is 60% or less when the arrangement pitch p is 400 nm. h ₀ also was found not. Therefore, it was found that when the arrangement pitch p is 400 nm, the antireflection structure 31 is not suitable.
Therefore, the protrusion 32 has a height h ₀ of 50 nm or more and 100 nm or less when the arrangement pitch p is 40 nm. When the arrangement pitch p is 100 nm, the height h ₀ is set to be 200 nm or more and 400 nm or less. Further, when the arrangement pitch p is 200 nm, the height h ₀ is set to 50 nm or more and 400 nm or less.
In the case of a pitch intermediate between the pitches, a height h ₀ is assumed according to the height corresponding to the front and rear pitches.

  And if it exceeds a certain height in each said pitch, it turns out that the sensitivity is falling. This is considered to be due to a decrease in light collection efficiency due to an increase in the optical path length in the light collecting structure, and it can be seen that the protrusion 32 has a limit height for application to the solid-state imaging device 1. The height of the limit varies with the pitch p.

Considering the range of the height h ₀ , the aspect ratio of the protrusion 32 is preferably 4 or less when the pitch is 100 nm. Further, when the pitch is 200 nm, it is preferably 2 or less. When the pitch is 40 nm, it is preferably 2.5 or less. Therefore, it can be said that the aspect ratio of the protrusion 32 is more preferably 2 or less.
In general, it is said that the higher the aspect ratio, the higher the function as the antireflection film of the fine concavo-convex structure. However, as described above, the solid-state imaging device 1 forms an unlimitedly high structure. This has been found undesirable in terms of sensitivity.

  Further, when the aspect ratio of the protrusion 32 was 1, a relationship between the sensitivity variation ratio and the pitch as shown in FIG. 7 was obtained. As shown in FIG. 7, when the aspect ratio of the protrusions 32 is 1, the pitch of the protrusions 32 is preferably 100 nm or more and 200 nm or less, and most preferably 200 nm.

In the solid-state imaging device 1, the antireflection structure 31 includes the spindle-shaped protrusions 32 having a light-transmitting and sinusoidal curved surface arranged over the entire surface of the passivation film 22. The volume change of the material on both sides of the interface changes linearly. For this reason, when the lateral size of the protrusion 32 is smaller than the wavelength of light, the space occupancy of one substance (flattening film 23) at the interface gradually changes, and the other substance (passivation film 22). ), The effective refractive index also changes continuously. The change in the space occupancy has the same meaning as the change in the volume of the substance on both sides of the interface, so that the change in the refractive index in the antireflection structure 31 is linear, and the reflection of light is reduced. Further, the protrusion 32 has a height of 50 nm to 100 nm when the arrangement pitch is 40 nm, and a height of 200 nm to 400 nm when the arrangement pitch is 100 nm, and the arrangement pitch is 200 nm. The height is not less than 50 nm and not more than 400 nm. Due to such a limitation, the aspect ratio of the protrusion 32 is not increased, and is, for example, 2 or less, the optical path length of light at the protrusion 32 is shortened, and a decrease in sensitivity is suppressed.
Accordingly, it is possible to prevent a decrease in sensitivity of the entire pixel, to prevent shading, and to prevent reflection. Therefore, since noise such as flare and ghost can be reduced, there is an advantage that a high-quality image with high sensitivity can be obtained.

In the above description, the passivation film 22 is described as the first light-transmitting film that is a film on which the antireflection structure 31 is formed. However, the position where the antireflection structure 31 is formed is limited to the surface of the passivation film 22. Not. For example, it is effective to form a film between films having a refractive index difference of 0.1 or more or at an interface with air. For example, the surface of the microlens 42 or the surface of the insulating film 16 that is the inorganic antireflection film may be used. Moreover, although not shown in figure, you may form in the surface of the cover glass formed in the outermost part into which incident light injects, or an infrared cut filter.
Further, the antireflection structure 31 may be formed in two layers or more layers, for example, a surface of the passivation film 22 and a surface of the microlens 42.

In particular, it is effective to form the reflecting structure of the present invention between films having a refractive index difference of 0.1 or more.
For example, on the microlens 42 (interface with air), on the passivation film 22 (interface with the planarizing film 23), on the inorganic antireflection film (insulating film 16) immediately above silicon (interface with the interlayer insulating film 21), photoelectric The conversion unit 12 (interface with the insulating film 16) and the like are suitable because the difference in refractive index is large.
In addition, the cover glass on the solid-state imaging device and the infrared (IR) cut filter are also suitable because of their large refractive index because of their interfaces with air.

<2. Second Embodiment>
[First Example of Manufacturing Method of Solid-State Imaging Device]
Next, a first example of a method for manufacturing a solid-state imaging device according to the second embodiment of the present invention will be described with reference to schematic configuration cross-sectional views in FIGS.

As shown in FIG. 8A, the photoelectric conversion unit 12 that converts incident light into signal charges is formed on the semiconductor substrate 11. For example, a silicon substrate is used as the semiconductor substrate 11. A vertical charge transfer unit 13 that reads and transfers signal charges from the photoelectric conversion unit 12 is formed on the semiconductor substrate 11. At the same time, a horizontal charge transfer unit (not shown) for transferring the signal charge sent from the vertical charge transfer unit 13 to the horizontal fragrance and outputting it is also formed. A transfer gate 15 is formed on the vertical charge transfer portion 13 (the same applies to the horizontal charge transfer portion) of the semiconductor substrate 11 via a gate insulating film 14. Further, the transfer gate 15 is covered with a light shielding film 17 via an insulating film 16. An opening 18 is provided on the photoelectric conversion unit 12 of the light shielding film 17.
Further, a plurality of light transmissive films are formed on the semiconductor substrate 11 so as to cover the photoelectric conversion unit 12, the light shielding film 17, and the like. For example, an interlayer insulating film 21 is formed. The interlayer insulating film 21 is formed of, for example, a silicon oxide-based insulating film, and is formed of, for example, a boron phosphorus silicate glass (BPSG) film. Of course, it may be formed of another silicon oxide insulating film.
Further, a passivation film 22 is formed. For example, the passivation film 22 is formed of, for example, a plasma CVD silicon nitride (P-SiN) film. The surface of the passivation film 22 is planarized by, for example, a chemical mechanical polishing method.

An ultraviolet curable film 51 is formed on the surface of the passivation film 22 which is the first light transmissive film among the plurality of light transmissive films. The ultraviolet curable film 51 is formed, for example, by applying an ultraviolet curable resin. Examples of the coating method include spin coating, slit coating, and nozzle coating. It is necessary to optimize the film thickness of the ultraviolet curable film 51 according to the moth-eye structure to be formed, and to set the remaining film in consideration of the influence of shrinkage.
That is, as shown in FIG. 9A, for example, when it is desired to form the antireflection structure 31 (moth eye structure) in which the height h ₀ of the protrusion pattern 52 (protrusion 32) is 200 nm, the thickness of the remaining film portion The film thickness h ₀ + h ₂ of the ultraviolet curable film 51 is set to 300 nm or more so that the thickness h ₂ is about 100 nm.

Next, as shown in FIG. 8B, a nanoimprint mold 61 having a three-dimensional inversion structure having a moth-eye structure to be formed is loaded above the semiconductor substrate 11. That is, in the nanoimprint mold 61, spindle-shaped concave portions 62 having a sinusoidal curved surface are arranged and formed on the entire surface.
The nanoimprint mold 61 is sized according to the substrate to be processed (semiconductor substrate 11), and in the case of transfer to a 300 mm wafer (semiconductor substrate 11), a 300 mm diameter nanoimprint mold 61 is prepared. The material of the nanoimprint mold 61 needs to transmit ultraviolet (UV) light, and examples thereof include materials that transmit ultraviolet light such as quartz, glass, and plastic.

  Next, as shown in FIG. 10 (3), an ultraviolet transmissive nanoimprint mold 61 is pressed against the ultraviolet curable film 51 to form a spindle-shaped recess 62 having a sinusoidal curved surface. Transfer to the surface. That is, the ultraviolet curable film 51 is filled in the concave portion of the nanoimprint mold 61. At this time, the filling time can be shortened by tilting the nanoimprint mold 61 and the semiconductor substrate 11. Further, the pressing may be performed by the dead weight of the nanoimprint mold 61. However, in order to shorten the filling time, it is possible to make the upper part of the nanoimprint mold 61 hermetically sealed and press it uniformly with air pressure or the like. When the ultraviolet curable film 51 is filled in the concave portion of the nanoimprint mold 61, the ultraviolet curable film 51 is cured by irradiation with ultraviolet rays (UV) for a sufficient time.

  Next, as shown in FIG. 10 (4), the nanoimprint mold 61 is released from the surface of the ultraviolet curable film 51. As a result, a spindle-shaped protrusion pattern 52 having a sinusoidal curved surface is formed on the surface of the ultraviolet curable film 51.

Next, as shown in FIG. 11 (5), the upper portions of the ultraviolet curable film 51 and the passivation film 22 are etched back. Then, the spindle-shaped protrusion pattern 52 (see FIG. 10 (4)) having a sinusoidal curved surface formed on the ultraviolet curable film 51 is transferred to the surface of the passivation film 22 as it is, and the spindle-shaped having a sinusoidal curved surface. A shaped protrusion 32 is formed. That is, in the protrusion 32, the volume change in the height direction of the protrusion 32 decreases linearly from the bottom to the top of the protrusion 32.
The protrusions 32 are formed to have a height of 50 nm to 100 nm when the arrangement pitch is 40 nm. When the arrangement pitch is 100 nm, the height is 200 nm or more and 400 nm or less. Further, when the arrangement pitch is 200 nm, the height is 50 nm or more and 400 nm or less.
In the transfer by the etch back, since a desired structure is formed in the recess 62 (see FIG. 10) in the nanoimprint mold 61 (see FIG. 10), the ultraviolet curable film 51 (see FIG. 10) to which the desired structure is transferred. It is desirable to faithfully transfer the shape of the protrusion pattern 52 (see FIG. 10) to the passivation film 22. For example, it is desirable to perform processing under conditions such that the selection ratio between the ultraviolet curable film 51 and the passivation film 22 is the same, such as by dry etching.
For example, using the Teijin Seiki TSR-820 UV curing films 51, when using a plasma CVD silicon nitride (P-SiN) film on the passivation film 22, sulfur hexafluoride as the etching gas (SF ₆₎ and oxygen (O ₂ ), a mixed gas of carbon tetrafluoride (CF ₄ ) and oxygen (O ₂ ), or a mixed gas of trifluoromethane (CHF ₃ ) and oxygen (O ₂ ). According to the anisotropic dry etching used, etching with the same selectivity can be performed.

Next, as shown in FIG. 11 (6), a planarizing film 23 is formed on the antireflection structure 31 having the moth-eye structure composed of the protrusions 32. The planarizing film 23 is formed by applying an organic film, for example. This step needs to be planarized for the formation of the color filter array in the next step.
In general, the flatness of the applied planarizing film 23 is improved by coating it sufficiently thick with respect to the height of the unevenness of the base (in this case, the antireflection structure 31).
However, in the solid-state imaging device, increasing the thickness of the planarizing film 23 leads to an increase in optical path length, that is, a loss of light collection efficiency.
Therefore, as shown in FIG. 9B, the film thickness h ₁ of the flattening film 23 is determined in accordance with the coating characteristics of the flattening film 23. Since it has been found that h _{1 of} 100 nm is necessary for the planarizing film 23 used in this embodiment, h ₁ ≧ h ₀ +100 nm. h ₀ is the height of the protrusion 32 of the antireflection structure 31.
However, since it is preferable that h ₁ is thin from the viewpoint of light collection efficiency, it is desirable to set so that h ₁ = about h ₀ +100 nm.
When nanoimprinting a 300 mm wafer in a batch is advantageous in terms of cost, it is necessary to consider mold release performance. The aspect suitable for mold release is 1 or less.
On the other hand, as described above, at a certain height, the larger the aspect, the better the antireflection performance.
In the present invention, an optimum value has been found in consideration of sensitivity, antireflection performance, and manufacturing problems. In FIG. 7, the pitch and sensitivity variation ratio when the aspect is 1 are plotted. In this case, the optimum values of the protrusions 32 are a pitch of 200 nm and a height of 200 nm.

Next, as shown in FIG. 12 (7), a color filter layer 41 is formed on the planarizing film 23. For the color filter layer 41, a green color filter layer G, a red color filter layer R, and a blue color filter layer B are sequentially formed by a normal manufacturing method, for example, by a coating method and a lithography technique. The order of formation is arbitrary.
In this way, by forming the color filter layer 41 through the planarizing film 23, damage during patterning when forming the color filter layer 41 is not applied to the protrusion 32, so the shape of the protrusion 32 Is retained.

  Further, a micro lens 42 is formed on the color filter layer 41 so as to guide incident light to the photoelectric conversion unit 12 by a normal lens forming technique.

  In this way, the solid-state imaging device 1 is manufactured.

When the antireflection structure 31 in which the protrusions 32 are arranged by the manufacturing method is formed on the passivation film 22, interface reflection is reduced, and sensitivity is improved by improving the light collection efficiency to the photoelectric conversion unit 12 of the solid-state imaging device 1. Will improve. For example, when the protrusions 32 having a pitch of 100 nm and a height of 400 nm are formed on the surface of the passivation film 22, a sensitivity improvement of 6% can be achieved.
Since the passivation film 22 has a step between the light receiving pixel unit including the photoelectric conversion unit 12 and the peripheral circuit unit due to the structure of the solid-state imaging device 1, it is very difficult to form the passivation film 22 uniformly on the light receiving pixel unit. . Therefore, the film non-uniformity of the light-receiving pixel portion means a change in the interference state of visible light, and therefore the sensitivity varies and causes color unevenness. By forming the antireflection structure 31 of the present invention on the passivation film 22, even if the film is non-uniform, there is an effect of reducing color unevenness. For example, when the antireflection structure 31 having the protrusions 32 having a pitch of 100 nm and a height of 400 nm is formed on the passivation film 22 of the silicon nitride film, the sensitivity variation with respect to the film thickness variation is 1 / It was possible to reduce to 3.
Further, when the antireflection structure 31 is formed on a film surface of the solid-state imaging device 1, the nanoimprint method capable of forming a 300 mm wafer at a time can be used to reduce the cost as compared with other forming methods. .

As described above, in the first manufacturing method, since the protrusion 32 of the antireflection structure 31 is formed in a spindle shape having a sinusoidal curved surface, the volume change of the substances on both sides of the interface of the antireflection structure 31 is changed. It will change linearly. For this reason, when the lateral size of the protrusion 32 is smaller than the wavelength of light, the space occupancy of one substance (flattening film 23) at the interface gradually changes, and the other substance (passivation film 22). ), The effective refractive index also changes continuously. Therefore, the refractive index change in the antireflection structure 31 is linear, and light reflection is reduced. Further, the protrusion 32 has a height of 50 nm to 100 nm when the arrangement pitch is 40 nm, and a height of 200 nm to 400 nm when the arrangement pitch is 100 nm, and the arrangement pitch is 200 nm. The height is not less than 50 nm and not more than 400 nm. Due to such a limitation, the aspect ratio of the protrusions is not increased and is 4 at the maximum, so that a decrease in sensitivity is suppressed. Preferably, the nanoimprint method can be easily adopted by setting the aspect ratio of the protrusion 32 to 2 or less, more preferably setting the aspect ratio to 1 or less.
Accordingly, it is possible to prevent a decrease in sensitivity of the entire pixel, to prevent shading, and to prevent reflection. These are because the sensitivity can be improved by reducing the aspect ratio of the protrusion 32, the mold release performance of the nanoimprint mold 61 can be improved, the planarization performance can be improved, and the optical path length can be reduced. Moreover, since the shape of the protrusion 32 is formed in a spindle shape having a sinusoidal curved surface, the antireflection performance is improved.
Therefore, since noise such as flare and ghost can be reduced, there is an advantage that a high-quality image with high sensitivity can be obtained.

[Second Example of Manufacturing Method of Solid-State Imaging Device]
A second example of the manufacturing method of the solid-state imaging device according to the second embodiment of the present invention will be described with reference to the manufacturing process sectional views of FIGS.

As shown in FIG. 13A, the photoelectric conversion unit 12 that converts incident light into signal charges is formed on the semiconductor substrate 11. For example, a silicon substrate is used as the semiconductor substrate 11. A vertical charge transfer unit 13 that reads and transfers signal charges from the photoelectric conversion unit 12 is formed on the semiconductor substrate 11. At the same time, a horizontal charge transfer unit (not shown) for transferring the signal charge sent from the vertical charge transfer unit 13 to the horizontal fragrance and outputting it is also formed. A transfer gate 15 is formed on the vertical charge transfer portion 13 (the same applies to the horizontal charge transfer portion) of the semiconductor substrate 11 via a gate insulating film 14. Further, the transfer gate 15 is covered with a light shielding film 17 via an insulating film 16. An opening 18 is provided on the photoelectric conversion unit 12 of the light shielding film 17.
Further, a plurality of light transmissive films are formed on the semiconductor substrate 11 so as to cover the photoelectric conversion unit 12, the light shielding film 17, and the like. For example, an interlayer insulating film 21 is formed. The interlayer insulating film 21 is formed of, for example, a silicon oxide-based insulating film, and is formed of, for example, a boron phosphorus silicate glass (BPSG) film. Of course, it may be formed of another silicon oxide insulating film.
Further, a passivation film 22 is formed. For example, the passivation film 22 is formed of, for example, a plasma CVD silicon nitride (P-SiN) film.
The surface of the passivation film 22 is planarized by, for example, a chemical mechanical polishing method.
An ultraviolet (UV) curable or thermosetting coating film 53 is formed on the planarized passivation film 22 which is the first light transmissive film among the plurality of light transmissive films. The refractive index of the coating film 53 is preferably as close as possible to that of the passivation film 22. For example, when the passivation film 22 is silicon nitride, since the refractive index is about 2, the coating film 53 is preferably siloxane containing titanium oxide (titania) particles. Other examples include polyimide resin. The coating film 53 is formed by coating, for example, and examples of the coating method include spin coating, slit coating, and nozzle coating. It is necessary to optimize the film thickness of the coating film 53 according to the moth-eye structure to be formed, and to set the remaining film in consideration of the influence of shrinkage.
That is, it is set similarly to the ultraviolet curable film 51. That is, as shown in FIG. 9 (1), for example, when the height h ₀ of the protrusion 32 is intended to form the anti-reflection structure 31 of 200 nm (moth-eye structure), the thickness h ₂ of the remaining film portion 100nm The film thickness h ₀ + h ₂ of the coating film 53 is set to 300 nm or more so as to be about the same.

Next, as shown in FIG. 13B, a nanoimprint mold 61 having a three-dimensional inversion structure of a moth-eye structure to be formed is loaded above the semiconductor substrate 11. That is, in the nanoimprint mold 61, spindle-shaped concave portions 62 having a sinusoidal curved surface are arranged and formed on the entire surface.
The nanoimprint mold 61 is sized according to the substrate to be processed (semiconductor substrate 11), and in the case of transfer to a 300 mm wafer (semiconductor substrate 11), a 300 mm diameter nanoimprint mold 61 is prepared. The material of the nanoimprint mold 61 needs to transmit ultraviolet (UV) light, and examples thereof include materials that transmit ultraviolet light such as quartz, glass, and plastic.

Next, as shown in FIG. 14 (3), when the coating film 53 is made of an ultraviolet curable resin, a UV-permeable nanoimprint mold 61 is pressed against the coating film 53 to form a spindle shape having a sinusoidal curved surface. The shape of the recess 62 is transferred to the surface of the coating film 53. That is, the coating film 53 is filled in the concave portion of the nanoimprint mold 61. At this time, the filling time can be shortened by tilting the nanoimprint mold 61 and the semiconductor substrate 11. Further, the pressing may be performed by the dead weight of the nanoimprint mold 61. However, in order to shorten the filling time, it is possible to make the upper part of the nanoimprint mold 61 hermetically sealed and press it uniformly with air pressure or the like. When the coating film 53 is filled in the concave portion of the nanoimprint mold 61, the coating film 53 is cured by irradiation with ultraviolet rays (UV) for a sufficient time.
Or when the said coating film 53 consists of thermosetting resin, it heats up to the curing temperature of the said coating film 53, and makes it cool after hardening. For example, when the coating film 53 is siloxane, it is cured by raising the temperature to 300 ° C. and holding it for 5 minutes.

  Next, as shown in FIG. 14 (4), the nanoimprint mold 61 is released from the surface of the coating film 53. As a result, a spindle-shaped protrusion 32 having a sinusoidal curved surface is formed on the surface of the coating film 53.

Next, as shown in FIG. 15 (5), a planarizing film 23 is formed on the antireflection structure 31 having the moth-eye structure composed of the protrusions 32. The planarizing film 23 is formed by applying an organic film, for example. This step needs to be planarized for the formation of the color filter array in the next step.
In general, the flatness of the applied planarizing film 23 is improved by coating it sufficiently thick with respect to the height of the unevenness of the base (in this case, the antireflection structure 31).
However, in the solid-state imaging device, increasing the thickness of the planarizing film 23 leads to an increase in optical path length, that is, a loss of light collection efficiency.
Therefore, as shown in FIG. 9B, the film thickness h ₁ of the flattening film 23 is determined in accordance with the coating characteristics of the flattening film 23. Since it has been found that h _{1 of} 100 nm is necessary for the planarizing film 23 used in this embodiment, h ₁ > h ₀ +100 nm. h ₀ is the height of the protrusion 32 of the antireflection structure 31.
However, since h ₁ is preferably thin from the viewpoint of light collection efficiency, it is desirable to set h ₁ to be about h ₀ +100 nm.
When nanoimprinting a 300 mm wafer in a batch is advantageous in terms of cost, it is necessary to consider mold release performance. The aspect most suitable for mold release is 1 or less.
On the other hand, as described above, the anti-reflection performance is more advantageous when the aspect is larger at a certain height.
In the present invention, an optimum value has been found in consideration of sensitivity, antireflection performance, and manufacturing problems. In FIG. 7, the pitch and sensitivity variation ratio when the aspect is 1 are plotted. In this case, the optimum values of the protrusions 32 are a pitch of 200 nm and a height of 200 nm.

Next, as shown in FIG. 15 (6), a color filter layer 41 is formed on the planarizing film 23. For the color filter layer 41, a green color filter layer G, a red color filter layer R, and a blue color filter layer B are sequentially formed by a normal manufacturing method, for example, by a coating method and a lithography technique. The order of formation is arbitrary.
In this way, by forming the color filter layer 41 through the planarizing film 23, damage during patterning when forming the color filter layer 41 is not applied to the protrusion 32, so the shape of the protrusion 32 Is retained.

  Further, a micro lens 42 is formed on the color filter layer 41 so as to guide incident light to the photoelectric conversion unit 12 by a normal lens forming technique.

  In this way, the solid-state imaging device 1 is manufactured.

When the antireflection structure 31 in which the protrusions 32 are arranged by the manufacturing method is formed on the passivation film 22, interface reflection is reduced, and sensitivity is improved by improving the light collection efficiency to the photoelectric conversion unit 12 of the solid-state imaging device 1. Will improve. For example, when the protrusions 32 having a pitch of 100 nm and a height of 400 nm are formed on the surface of the passivation film 22, a sensitivity improvement of 6% can be achieved.
Since the passivation film 22 has a step between the light receiving pixel unit including the photoelectric conversion unit 12 and the peripheral circuit unit due to the structure of the solid-state imaging device 1, it is very difficult to form the passivation film 22 uniformly on the light receiving pixel unit. . Therefore, the film non-uniformity of the light-receiving pixel portion means a change in the interference state of visible light, and therefore the sensitivity varies and causes color unevenness. By forming the antireflection structure 31 of the present invention on the passivation film 22, even if the film is non-uniform, there is an effect of reducing color unevenness. For example, when the antireflection structure 31 having the protrusions 32 having a pitch of 100 nm and a height of 400 nm is formed on the passivation film 22 of the silicon nitride film, the sensitivity variation with respect to the film thickness variation is 1 / It was possible to reduce to 3.
Further, when the antireflection structure 31 is formed on a film surface of the solid-state imaging device 1, the nanoimprint method capable of forming a 300 mm wafer at a time can be used to reduce the cost as compared with other forming methods. .

As described above, in the first manufacturing method, since the protrusion 32 of the antireflection structure 31 is formed in a spindle shape having a sinusoidal curved surface, the volume change of the substances on both sides of the interface of the antireflection structure 31 is changed. It will change linearly. For this reason, when the lateral size of the protrusion 32 is smaller than the wavelength of light, the space occupancy of one substance (flattening film 23) at the interface gradually changes, and the other substance (passivation film 22). ), The effective refractive index also changes continuously. Therefore, the refractive index change in the antireflection structure 31 is linear, and light reflection is reduced. Further, the protrusion 32 has a height of 50 nm to 100 nm when the arrangement pitch is 40 nm, and a height of 200 nm to 400 nm when the arrangement pitch is 100 nm, and the arrangement pitch is 200 nm. The height is not less than 50 nm and not more than 400 nm. Due to such a limitation, the aspect ratio of the protrusions is not increased and is 4 at the maximum, so that a decrease in sensitivity is suppressed. Preferably, the nanoimprint method can be easily adopted by setting the aspect ratio of the protrusion 32 to 2 or less, more preferably setting the aspect ratio to 1 or less.
Accordingly, it is possible to prevent a decrease in sensitivity of the entire pixel, to prevent shading, and to prevent reflection. These are because the sensitivity can be improved by reducing the aspect ratio of the protrusion 32, the mold release performance of the nanoimprint mold 61 can be improved, the planarization performance can be improved, and the optical path length can be reduced. Moreover, since the shape of the protrusion 32 is formed in a spindle shape having a sinusoidal curved surface, the antireflection performance is improved.
Therefore, since noise such as flare and ghost can be reduced, there is an advantage that a high-quality image with high sensitivity can be obtained.

In the first and second manufacturing methods, the manufacturing method for forming the antireflection structure 31 on the surface of the passivation film 22 has been described. However, for example, the surface of the microlens 42 or the inorganic antireflection film can be formed by either of the manufacturing methods. It may be formed on the surface of the insulating film 16. Moreover, although not shown in figure, you may form in the surface of the cover glass formed in the outermost part into which incident light injects, or an infrared cut filter.
Moreover, according to the 1st manufacturing method, it can form also in the photoelectric conversion part 12 surface (silicon substrate surface).
Furthermore, the antireflection structure 31 may be formed in two or more layers, for example, the surface of the passivation film 22 and the surface of the microlens 42.

<3. Third Embodiment>
[Example of configuration of imaging apparatus]
Next, an example of the configuration of an imaging apparatus according to the third embodiment of the present invention will be described with reference to the block diagram of FIG. This imaging device uses the solid-state imaging device of the present invention.

  As illustrated in FIG. 16, the imaging device 200 includes a solid-state imaging device 210 in the imaging unit 201. A condensing optical unit 202 that forms an image is provided on the condensing side of the image pickup unit 201, and the image pickup unit 201 receives a signal that is photoelectrically converted by a driving circuit that drives the image pickup unit 201 and the solid-state image pickup device 210. A signal processing unit 203 having a signal processing circuit or the like for processing an image is connected. The image signal processed by the signal processing unit 203 can be stored by an image storage unit (not shown). In such an imaging apparatus 200, the solid-state imaging apparatus 1 described in the above embodiment can be used as the solid-state imaging apparatus 210.

  The imaging device 200 of the present invention has the advantage that a high-sensitivity and high-quality image can be obtained because the solid-state imaging device 1 capable of obtaining a high-sensitivity and high-quality image of the present invention is used.

  In addition, the imaging device 200 may be formed as a single chip, or may be in a modular form having an imaging function in which an imaging unit and a signal processing unit or an optical system are packaged together. May be. The imaging device 200 here refers to, for example, a camera or a portable device having an imaging function. “Imaging” includes not only capturing an image during normal camera shooting but also fingerprint detection in a broad sense.

  DESCRIPTION OF SYMBOLS 1 ... Solid-state imaging device, 11 ... Semiconductor substrate (semiconductor area | region), 12 ... Photoelectric conversion part, 22 ... Passivation film (1st light transmissive film | membrane), 31 ... Antireflection structure, 32 ... Projection body, 51 ... Ultraviolet curing Membrane, 53 ... coating film, 61 ... mold for nanoimprint, 62 ... recess, 200 ... imaging device, 201 ... imaging unit, 202 ... condensing optical unit, 203 ... signal processing unit, 210 ... solid-state imaging device (solid-state imaging device 1) )

Claims (11)

A photoelectric conversion unit that photoelectrically converts incident light into a semiconductor region to obtain a signal charge; and
Comprising a plurality of light-transmitting films formed on the photoelectric conversion part,
An antireflection structure is formed on the surface of the semiconductor region or the surface of the first light transmissive film of at least one of the plurality of light transmissive films,
The antireflection structure is
A spindle-shaped protrusion having a light transmission and a sinusoidal surface arranged on the surface of the first light transmission film or the surface of the semiconductor region,
The protrusions have a height of 50 nm to 100 nm when the arrangement pitch is 40 nm, a height of 200 nm to 400 nm when the arrangement pitch is 100 nm, and a height when the arrangement pitch is 200 nm. A solid-state imaging device having a thickness of 50 nm to 400 nm. The solid-state imaging device according to claim 1, wherein a volume change in the height direction of the protrusion is linearly reduced from the bottom to the top of the protrusion. The solid-state imaging device according to claim 1, wherein the first light-transmitting film is a microlens that collects incident light on the photoelectric conversion unit. The solid-state imaging device according to claim 1, wherein the first light transmissive film is a passivation film formed above the photoelectric conversion unit. The solid-state imaging device according to claim 1, wherein the first light-transmitting film is an inorganic antireflection film formed on the photoelectric conversion unit. The solid-state imaging device according to claim 1, wherein the first light-transmitting film is a cover glass or an infrared cut filter formed on an outermost part on which the incident light is incident. When forming a plurality of light-transmitting films on a photoelectric conversion unit that photoelectrically converts incident light into a semiconductor region to obtain a signal charge,
Forming an antireflection structure on the surface of the first light transmissive film of at least one of the plurality of light transmissive films,
The step of forming the antireflection structure includes
Forming an ultraviolet curable film on the surface of the first light transmissive film;
The ultraviolet curable film is pressed with an ultraviolet light permeable nanoimprint mold having spindle-shaped concave portions having a sinusoidal curved surface, and the shape of the spindle-shaped concave portions having a sinusoidal curved surface is transferred to the surface of the ultraviolet cured film. And a process of
A step of irradiating and curing the ultraviolet curable film with the nanoimprint mold pressed against the ultraviolet curable film;
Removing the mold for nanoimprint from the ultraviolet curable film,
Etching back the upper part of the UV curable film and the first light transmissive film, and transferring the shape of a spindle-shaped protrusion having a sinusoidal surface formed on the UV curable film to the surface of the first light transmissive film. Comprising the step of
The protrusions are formed with a height of 50 nm to 100 nm when the pitch of the array is 40 nm. When the pitch of the array is 100 nm, the protrusion is formed with a height of 200 nm to 400 nm and the pitch of the array is 200 nm. A method for manufacturing a solid-state imaging device, wherein the height is 50 nm or more and 400 nm or less. The method for manufacturing a solid-state imaging device according to claim 7, wherein a volume change in the height direction of the protrusion is linearly reduced from the bottom to the top of the protrusion. When forming a plurality of light-transmitting films on a photoelectric conversion unit that photoelectrically converts incident light into a semiconductor region to obtain a signal charge,
Forming an antireflection structure on the surface of the first light transmissive film of at least one of the plurality of light transmissive films,
The step of forming the antireflection structure includes
Forming the first light transmissive film with an ultraviolet curable or thermosetting coating film;
An ultraviolet light transmissive nanoimprint mold in which spindle-shaped concave portions having a sinusoidal surface are arranged on the entire surface is pressed against the first light-transmitting film, so that the shape of the spindle-shaped concave portion having a sinusoidal curved surface is changed to the first light transmitting film. Transferring to the surface of the conductive film;
Irradiating the first light-transmitting film with ultraviolet rays in a state of pressing the nanoimprint mold;
Removing the mold for nanoimprinting from the first light transmissive film,
The protrusions are formed with a height of 50 nm to 100 nm when the pitch of the array is 40 nm. When the pitch of the array is 100 nm, the protrusion is formed with a height of 200 nm to 400 nm and the pitch of the array is 200 nm. A method for manufacturing a solid-state imaging device, wherein the height is 50 nm or more and 400 nm or less. The method for manufacturing a solid-state imaging device according to claim 9, wherein a volume change in the height direction of the protrusion is linearly reduced from the bottom to the top of the protrusion. A condensing optical unit that condenses incident light;
An imaging unit having a solid-state imaging device that receives and photoelectrically converts light collected by the condensing optical unit;
A signal processing unit for processing the photoelectrically converted signal;
The solid-state imaging device
A photoelectric conversion unit that photoelectrically converts incident light into a semiconductor region to obtain a signal charge; and
Comprising a plurality of light-transmitting films formed on the photoelectric conversion part,
An antireflection structure is formed on the surface of the semiconductor region or the surface of the first light transmissive film of at least one of the plurality of light transmissive films,
The antireflection structure is
A spindle-shaped protrusion having a light transmission and a sinusoidal surface arranged on the surface of the first light transmission film or the surface of the semiconductor region,
The spindle-shaped protrusions have a height of 50 nm to 100 nm when the arrangement pitch is 40 nm, and a height of 200 nm to 400 nm when the arrangement pitch is 100 nm, and the arrangement pitch is 200 nm. In the case, the imaging device whose height is 50 nm or more and 400 nm or less.