JP2010199299A - Solid-state imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain low height and improve condensing property. <P>SOLUTION: The solid-state imaging device includes a semiconductor substrate 20, a light reception section 30 formed on the surface of the semiconductor substrate, a film 10 formed on the semiconductor substrate, a waveguide 12 formed inside from the surface of the film on the upper side of the light reception section, a first high refractive index layer 13 formed on the bottom in the waveguide, and a color filter 14 that is formed within the waveguide on the first high refractive index layer and has smaller refractive index than the first high refractive index layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device in which a color filter and a high refractive index layer are formed in a waveguide having a pixel structure.

  In recent solid-state imaging devices, pixel pitches have been narrowed due to demands for high resolution and chip size reduction, and it has become difficult to maintain sensitivity and color mixing due to the reduction in aperture and light receiving surface area. Further, since the chip size is reduced, the number of wiring layers is increased in the pixel portion, and sensitivity reduction and color mixing deterioration caused by an increase in the distance from the microlens to the light receiving portion are also problematic. For this reason, there is a demand for a reduction in the height of the pixel portion as the pixel pitch is reduced, and it is necessary to reduce the height not only in the base structure but also in the color filter layer.

  In the ground structure, the height of the light receiving portion is reduced by forming the multilayer wiring outside the light receiving portion. In addition, sensitivity is maintained and color mixing is reduced by forming a waveguide on the light receiving portion. However, in the color filter layer, in order to maintain desired spectral characteristics in the pigment, dye and photonic filter, a certain film thickness is essential. On the other hand, the color filter layer is formed above the waveguide embedded with only the high refractive index layer. In the color filter layer having such a structure, since it is necessary to maintain the spectrum from the viewpoint of color reproducibility, there is a present situation in which the film thickness cannot be reduced. Accordingly, there is a limit to reducing the height of the pixel structure.

  In Patent Document 1, by forming only the color filter in the waveguide, the film thickness of the color filter is secured by utilizing the depth of the waveguide, and the light receiving portion is further reduced in height. . However, since the light passing through the color filter is diffused, it is difficult to capture the light into the light receiving unit.

JP 2007-287819 A

  The present invention provides a solid-state imaging device capable of improving light collecting performance while realizing a low profile.

  A solid-state imaging device according to an aspect of the present invention includes a semiconductor substrate, a light receiving portion formed on the surface of the semiconductor substrate, a film formed on the semiconductor substrate, and a surface of the film above the light receiving portion. A waveguide formed inside, a first high refractive index layer formed at the bottom of the waveguide, and the first high refractive index formed in the waveguide on the first high refractive index layer. And a color filter having a refractive index smaller than that of the refractive index layer.

  ADVANTAGE OF THE INVENTION According to this invention, the solid-state imaging device which can aim at the improvement of condensing property can be provided, implement | achieving low profile.

1 is a cross-sectional view illustrating a pixel structure of a solid-state imaging device according to a first embodiment of the present invention. Sectional drawing which shows the modification of the pixel structure of the solid-state imaging device which concerns on the 1st Embodiment of this invention. 3A is a cross-sectional view showing a manufacturing process of the pixel structure of the solid-state imaging device according to the first embodiment of the present invention, and FIG. 3B is a diagram of the present invention continued from FIG. Sectional drawing which shows the manufacturing process of the pixel structure of the solid-state imaging device which concerns on 1 embodiment, FIG.3 (c) is a pixel of the solid-state imaging device which concerns on the 1st Embodiment of this invention following FIG.3 (b). FIG. 3D is a cross-sectional view showing the manufacturing process of the pixel structure of the solid-state imaging device according to the first embodiment of the present invention, FIG. (E) is sectional drawing which shows the manufacturing process of the pixel structure of the solid-state imaging device concerning the 1st Embodiment of this invention following FIG.3 (d), FIG.3 (f) is FIG.3 (e). FIG. 5 is a cross-sectional view illustrating a manufacturing process of the pixel structure of the solid-state imaging device according to the first embodiment of the present invention. Sectional drawing which shows the modification of the pixel structure of the solid-state imaging device which concerns on the 1st Embodiment of this invention. FIG. 5A is a cross-sectional view showing a manufacturing process of a modification of the pixel structure of the solid-state imaging device according to the first embodiment of the present invention, and FIG. 5B is a diagram following FIG. Sectional drawing which shows the manufacturing process of the modification of the pixel structure of the solid-state imaging device concerning the 1st Embodiment of the invention, FIG.5 (c) follows the 1st Embodiment of this invention following FIG.5 (b). Sectional drawing which shows the manufacturing process of the modification of the pixel structure of the solid-state imaging device which concerns. Sectional drawing which shows the pixel structure of the solid-state imaging device which concerns on the 2nd Embodiment of this invention. FIG. 7A is a cross-sectional view illustrating a manufacturing process of a pixel structure of a solid-state imaging device according to the second embodiment of the present invention, and FIG. 7B is a diagram of the present invention continued from FIG. Sectional drawing which shows the manufacturing process of the pixel structure of the solid-state imaging device which concerns on 2 embodiment, FIG.7 (c) is a pixel of the solid-state imaging device which concerns on the 2nd Embodiment of this invention following FIG.7 (b). FIG. 7D is a cross-sectional view illustrating the manufacturing process of the pixel structure of the solid-state imaging device according to the second embodiment of the present invention, FIG. (E) is sectional drawing which shows the manufacturing process of the pixel structure of the solid-state imaging device concerning the 2nd Embodiment of this invention following FIG.7 (d). Sectional drawing which shows the modification of the pixel structure of the solid-state imaging device which concerns on the 2nd Embodiment of this invention. Sectional drawing which shows the pixel structure of the solid-state imaging device which concerns on the 3rd Embodiment of this invention. FIG. 10A is a cross-sectional view showing a manufacturing process of a pixel structure of a solid-state imaging device according to the third embodiment of the present invention, and FIG. 10B is a diagram of the present invention continued from FIG. Sectional drawing which shows the manufacturing process of the pixel structure of the solid-state imaging device which concerns on 3rd Embodiment, FIG.10 (c) is a pixel of the solid-state imaging device which concerns on the 3rd Embodiment of this invention following FIG.10 (b). Sectional drawing which shows the manufacturing process of a structure, FIG.10 (d) is sectional drawing which shows the manufacturing process of the pixel structure of the solid-state imaging device which concerns on the 3rd Embodiment of this invention following FIG.10 (c). Sectional drawing which shows the modification of the pixel structure of the solid-state imaging device which concerns on the 3rd Embodiment of this invention. Sectional drawing which shows the pixel structure of the solid-state imaging device which concerns on the 4th Embodiment of this invention. FIG. 13A is a cross-sectional view showing a manufacturing process of a pixel structure of a solid-state imaging device according to the fourth embodiment of the present invention, and FIG. 13B is a diagram of the present invention continued from FIG. Sectional drawing which shows the manufacturing process of the pixel structure of the solid-state imaging device which concerns on 4 embodiment, FIG.13 (c) is a pixel of the solid-state imaging device which concerns on the 4th Embodiment of this invention following FIG.13 (b). Sectional drawing which shows the manufacturing process of a structure. Sectional drawing which shows the modification of the pixel structure of the solid-state imaging device which concerns on the 4th Embodiment of this invention. Sectional drawing which shows the pixel structure of the solid-state imaging device which concerns on the 5th Embodiment of this invention. FIG. 16A is a cross-sectional view illustrating a manufacturing process of a pixel structure of a solid-state imaging device according to the fifth embodiment of the present invention, and FIG. 16B is a diagram of the present invention continued from FIG. Sectional drawing which shows the manufacturing process of the pixel structure of the solid-state imaging device which concerns on 5 embodiment. Sectional drawing which shows the pixel structure of the solid-state imaging device which concerns on the 6th Embodiment of this invention. Sectional drawing which shows the manufacturing process of the pixel structure of the solid-state imaging device which concerns on the 6th Embodiment of this invention. Sectional drawing which shows the modification of the pixel structure of the solid-state imaging device which concerns on the 6th Embodiment of this invention. Sectional drawing which shows the modification of the pixel structure of the solid-state imaging device which concerns on the 6th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the description, common parts are denoted by common reference symbols throughout the drawings.

[First Embodiment]
The first embodiment is an example in which a high refractive index layer / color filter is formed in a waveguide formed in a pixel structure.

[Construction]
First, the pixel structure of the solid-state imaging device according to this embodiment will be described. FIG. 1 is a cross-sectional view of a pixel structure of a solid-state imaging device according to this embodiment.

  As shown in FIG. 1, the pixel structure of the solid-state imaging device according to this embodiment includes a silicon substrate (semiconductor substrate) 20, a light receiving unit (for example, a photodiode) 30, an insulating film (film) 10, wiring 11, and a waveguide. 12, a high refractive index layer 13, a color filter 14, a planarization layer 15, and a microlens 16.

  A plurality of light receiving portions 30 are formed on the surface of the silicon substrate 20. An insulating film 10 is formed on the light receiving unit 30 and the silicon substrate 20. A waveguide 12 is provided from the surface of the insulating film 10 above the light receiving unit 30 to the inside thereof. A plurality of wirings 11 are formed in the insulating film 10 around the waveguide 12. A high refractive index layer 13 is formed at the bottom of the waveguide 12. A color filter 14 is formed on the high refractive index layer 13, and the waveguide 12 is embedded with the high refractive index layer 13 and the color filter 14. A planarizing layer 15 is formed on the entire surface of the color filter 14 and the insulating film 10. A microlens 16 is formed on the planarizing layer 15 corresponding to the waveguide 12.

  Here, the film is not limited to the insulating film 10 but may be a metal layer, a semiconductor layer, a dielectric layer, or a laminated film thereof. Further, the refractive index of the high refractive index layer 13 is desirably 1.5 or more, for example. Further, the refractive index of the color filter 14 is preferably smaller than the refractive index of the high refractive index layer 13.

  As shown in FIG. 2, in the waveguide 12, a double layer composed of a low refractive index layer 40 and a high refractive index layer 50 is interposed between the high refractive index layer 13 and the color filter 14 and the insulating film 10. A reflective film 60 having a structure may be formed. That is, the low refractive index layer 40 may be formed on the side surface and the bottom surface in the waveguide 12, and the high refractive index layer 50 may be formed inside the low refractive index layer 40. The high refractive index layer 50 may be the same material as the high refractive index layer 13. The refractive index of the low refractive index layer 40 is preferably smaller than the refractive index of the high refractive index layer 50. Due to the difference in refractive index between the low refractive index layer 40 and the high refractive index layer 50, the reflective film 60 reflects light. That is, the light that has entered the waveguide 12 is reflected on the side surface of the waveguide 12 without entering the insulating film 10, and travels to the bottom of the waveguide 12. The reflective film 60 can be applied to all the following embodiments.

[Production method]
Next, a method for manufacturing the pixel structure of the solid-state imaging device according to this embodiment will be described. 3A to 3F are cross-sectional views showing a manufacturing process of the pixel structure of FIG.

  First, as shown in FIG. 3A, a plurality of wirings 11 and insulating films 10 are alternately and sequentially formed on a silicon substrate 20 on which a plurality of light receiving portions 30 are formed. Thus, the wiring 11 is formed inside the insulating film 10 outside the light receiving unit 30. Further, the wiring 11 is formed in a region other than above the light receiving unit 30. Examples of the material of the insulating film 10 include a silicon oxide film and a silicon nitride film. Examples of the material of the wiring 11 include aluminum and copper.

  Next, as shown in FIG. 3B, a groove to be the waveguide 12 is formed by etching in the insulating film 10 on the light receiving portion 30. The waveguide 12 is formed between the wirings 11. Thereafter, a dual structure layer (not shown) of the low refractive index layer 40 and the high refractive index layer 50 may be formed on the surface of the waveguide 12.

  Next, as shown in FIG. 3C, a high refractive index layer 13 is formed in the waveguide 12. Thereby, the waveguide 12 is embedded with the high refractive index layer 13, and the high refractive index layer 13 is continuously formed on the insulating film 10.

  Next, as shown in FIG. 3D, the high refractive index layer 13 on the insulating film 10 and in the waveguide 12 is removed by etch back. As a result, the high refractive index layer 13 remains only at the bottom of the waveguide 12. That is, the upper surface of the high refractive index layer 13 is positioned below the upper surface of the insulating film 10.

  Next, as shown in FIG. 3E, the color filter 14 is formed on the high refractive index layer 13 in the waveguide 12. The color filter 14 is formed on the upper portion of the waveguide 12 and on the insulating film 10, and has the same height as the insulating film 10 by lithography and etch back. The waveguide 12 is embedded with the high refractive index layer 13 and the color filter 14. The film thickness of the color filter 14 is 0.4 μm or more, for example. By securing this film thickness, the color filter 14 can maintain desired spectral characteristics in the pigment, dye, and photonic filter.

  Next, as shown in FIG. 3F, a planarizing layer 15 is formed on the entire surface of the color filter 14 and the insulating film 10. Thereby, the entire surface of the color filter 14 and the insulating film 10 is flattened.

  Next, as shown in FIG. 1, a microlens 16 is formed on the planarization layer 15 corresponding to the waveguide 12. In this way, the pixel structure of the solid-state imaging device according to this embodiment is completed.

[effect]
According to the first embodiment, the high refractive index layer 13 is formed at the bottom of the waveguide 12 formed in the pixel structure, and the waveguide 12 on the high refractive index layer 13 is formed at the top. By forming the color filter 14, the waveguide 12 is embedded. That is, a high refractive index layer 13 having a refractive index higher than that of the color filter 14 is formed under the color filter 14 in the waveguide 12. Thus, even if light incident from the microlens 16 passes through the color filter 14 and light diffusion occurs, light diffusion can be reduced by the high refractive index layer 13. Accordingly, it is possible to improve the light collecting property in the pixel structure.

  Further, since the color filter 14 is formed in the waveguide 12, the distance from the microlens 16 to the light receiving unit 30 is shorter than in the conventional case where the color filter 14 is formed on the waveguide 12, and the pixel The height of the structure can be reduced. As a result, it is possible to reduce sensitivity reduction and color mixture deterioration in the pixel structure.

  Furthermore, as described above, since it is necessary to maintain the spectrum from the viewpoint of color reproducibility, the thickness of the color filter 14 cannot be reduced. However, in the present embodiment, since the color filter 14 is formed in the waveguide 12, the film thickness of the color filter 14 can be secured by using the depth of the waveguide 12, and the color filter 14 can be maintained.

[Modification]
Hereinafter, a modification of the pixel structure of the solid-state imaging device according to the present embodiment and a manufacturing method thereof will be described.

  FIG. 4 shows a modification of the pixel structure of the solid-state imaging device according to this embodiment. As shown in FIG. 4, in this embodiment, high refraction occurs between the color filter 14 and the insulating film 10 on the side surface in the waveguide 12 and between the planarizing layer 15 and the insulating film 10 above the wiring 11. The rate layer 13 may be formed. That is, the high refractive index layer 13 may be continuously formed from the bottom in the waveguide 12 to the upper side surface in the waveguide 12 and the insulating film 10.

  5A to 5C show a manufacturing process of a modification example of the pixel structure of the solid-state imaging device according to the present embodiment.

  First, the steps of FIGS. 3A to 3C in the present embodiment are performed.

  Next, as shown in FIG. 5A, the high refractive index layer 13 on the insulating film 10 and in the upper portion of the waveguide 12 is removed by etch back. At this time, the high refractive index material 13 on the insulating film 10 and on the upper side surface in the waveguide 12 is not completely removed but remains.

  Next, as shown in FIG. 5B, the color filter 14 is formed on the high refractive index layer 13 in the waveguide 12. The color filter 14 is formed inside the waveguide 12 and on the high refractive index layer 13 on the insulating film 10. However, the color filter 14 becomes the same height as the high refractive index layer 13 by lithography and etchback. Is embedded.

  Next, as shown in FIG. 5C, the planarization layer 15 is formed on the entire surface of the color filter 14 and the high refractive index layer 13.

  Next, as shown in FIG. 4, a microlens 16 is formed on the planarizing layer 15 corresponding to the waveguide 12. In this way, a modification of the pixel structure of the solid-state imaging device according to this embodiment is completed.

  Also in this modification, the same effect as that of the present embodiment can be obtained.

[Second Embodiment]
The second embodiment is an example in which a high refractive index layer / antireflection layer / color filter is formed in a waveguide formed in a pixel structure. Here, the description of the same points as in the first embodiment will be omitted, and different points will be described in detail.

[Construction]
First, the pixel structure of the solid-state imaging device according to this embodiment will be described. FIG. 6 is a cross-sectional view of the pixel structure of the solid-state imaging device according to this embodiment.

  As shown in FIG. 6, the pixel structure of the solid-state imaging device according to the present embodiment is different from the first embodiment in that an antireflection layer 17 is formed between the high refractive index layer 13 and the color filter 14. It is a point. That is, the high refractive index layer 13 is formed at the bottom of the waveguide 12, and the antireflection layer 17 is formed on the high refractive index layer 13. A color filter 14 is formed on the antireflection layer 17. Therefore, the inside of the waveguide 12 is embedded with the high refractive index layer 13 / antireflection layer 17 / color filter 14.

  Here, the refractive index of the antireflection layer 17 is preferably smaller than the refractive index of the high refractive index layer 13 and larger than the refractive index of the color filter 14.

[Production method]
Next, a method for manufacturing the pixel structure of the solid-state imaging device according to this embodiment will be described. 7A to 7E are cross-sectional views showing a manufacturing process of the pixel structure of the solid-state imaging device according to the present embodiment.

  First, steps (a) to (c) of FIG. 3 in the first embodiment are performed.

  Next, as shown in FIG. 7A, the high refractive index layer 13 on the insulating film 10 and in the waveguide 12 is removed. As a result, the high refractive index layer 13 remains only at the bottom in the waveguide 12.

  Next, as shown in FIG. 7B, the antireflection layer 17 is formed on the high refractive index layer 13 and the insulating film 10 in the waveguide 12. As a result, the waveguide 12 is embedded with the antireflection layer 17 and the antireflection layer 17 is formed on the insulating film 10.

  Next, as shown in FIG. 7C, the antireflection layer 17 on the insulating film 10 and in the waveguide 12 is removed by etch back.

  Next, as shown in FIG. 7D, the color filter 14 is formed on the antireflection layer 17 in the waveguide 12. The color filter 14 is formed inside the waveguide 12 and on the high-refractive index layer 13 on the insulating film 10, but becomes the same height as the insulating film 10 by lithography and etchback, and the waveguide 12 is embedded. It is.

  Next, as shown in FIG. 7E, a planarizing layer 15 is formed on the entire surface of the color filter 14 and the insulating film 10.

  Next, as shown in FIG. 6, a microlens 16 is formed on the planarizing layer 15 corresponding to the waveguide 12. In this way, the pixel structure of the solid-state imaging device according to this embodiment is completed.

[effect]
According to the second embodiment, the same effect as that of the first embodiment can be obtained.

  Furthermore, in the second embodiment, an antireflection layer 17 is formed between the high refractive index layer 13 and the color filter 14 in the waveguide 12. The refractive index of the antireflection layer 17 is smaller than the refractive index of the high refractive index layer 13 and larger than the refractive index of the color filter 14. Thereby, reflection of light due to a difference in refractive index at the interface between the high refractive index layer 13 and the color filter 14 can be prevented.

[Modification]
Hereinafter, a modification of the pixel structure of the solid-state imaging device according to the present embodiment and a manufacturing method thereof will be described.

  FIG. 8 shows a modification of the pixel structure of the solid-state imaging device according to this embodiment. As shown in FIG. 8, in this embodiment, planarization between the antireflection layer 17 and the insulating film 10 on the side surface in the waveguide 12, between the color filter 14 and the insulating film 10, and above the wiring 11. A high refractive index layer 13 may be formed between the layer 15 and the insulating film 10.

  The manufacturing process of the modified example of the pixel structure of the solid-state imaging device according to the present embodiment is performed in the same manner as the modified example of the first embodiment. That is, as shown in FIG. 5A, when the high refractive index layer 13 on the insulating film 10 and in the waveguide 12 is removed, the high refractive index layer 13 is not completely removed and remains. To do. Thereafter, an antireflection layer 17, a color filter 14, a planarization layer 15, and a microlens 16 are formed on the remaining high refractive index layer 13, and a modification of the pixel structure of the solid-state imaging device according to this embodiment is completed. .

[Third Embodiment]
The third embodiment is an example in which a high refractive index layer / color filter / high refractive index layer is formed in a waveguide formed in a pixel structure. Here, the description of the same points as in the first embodiment will be omitted, and different points will be described in detail.

[Construction]
First, the pixel structure of the solid-state imaging device according to this embodiment will be described. FIG. 9 is a cross-sectional view of the pixel structure of the solid-state imaging device according to this embodiment.

  As shown in FIG. 9, the pixel structure of the solid-state imaging device according to the present embodiment is different from the first embodiment in that the high refractive index layer 13 ′ is formed on the color filter 14 formed in the waveguide 12. Is formed. That is, the high refractive index layer 13 is formed at the bottom of the waveguide 12, and the color filter 14 is formed on the high refractive index layer 13. Further, a high refractive index layer 13 ′ is formed on the color filter 14. Therefore, the inside of the waveguide 12 is embedded by the high refractive index layer 13 / color filter 14 / high refractive index layer 13 '.

  Here, the high refractive index layer 13 ′ may be made of the same material as that of the high refractive index layer 13, but is not limited thereto, as long as the refractive index is larger than that of the microlens 16.

[Production method]
Next, a method for manufacturing the pixel structure of the solid-state imaging device according to this embodiment will be described. 10A to 10D are cross-sectional views illustrating a manufacturing process of the pixel structure of the solid-state imaging device according to the present embodiment.

  First, the steps of FIGS. 3A to 3C in the first embodiment are performed.

  Next, as shown in FIG. 10A, the high refractive index layer 13 on the insulating film 10 and in the waveguide 12 is removed. As a result, the high refractive index layer 13 remains only at the bottom in the waveguide 12.

  Next, as shown in FIG. 10B, the color filter 14 is formed on the high refractive index layer 13 in the waveguide 12.

  Next, as shown in FIG. 10C, a high refractive index layer 13 ′ is formed on the color filter 14 in the waveguide 12. The high refractive index layer 13 ′ is formed to the same height as the insulating film 10 by etch back, and the waveguide 12 is embedded.

  Next, as shown in FIG. 10D, the planarizing layer 15 is formed on the entire surface of the high refractive index layer 13 ′ and the insulating film 10.

  Next, as shown in FIG. 9, a microlens 16 is formed on the planarizing layer 15 corresponding to the waveguide 12. In this way, the pixel structure of the solid-state imaging device according to this embodiment is completed.

[effect]
According to the third embodiment, the same effect as in the first embodiment can be obtained.

  Furthermore, in the third embodiment, the high refractive index layer 13 is formed under the color filter 14, and the high refractive index layer 13 ′ is formed on the color filter 14. Thereby, the light diffusion by the microlens 16 can be reduced by the high refractive index layer 13 ′, and the light diffusion by the color filter 14 can be reduced by the high refractive index layer 13. Therefore, it is possible to improve the light condensing property in the pixel structure as compared with the first embodiment.

  In the waveguide 12 of this embodiment, an antireflection layer 17 is formed between at least one of the high refractive index layer 13 and the color filter 14 and between the high refractive index layer 13 ′ and the color filter 14. May be. In this case, the same effect as in the second embodiment can be obtained.

[Modification]
Hereinafter, a pixel structure of the solid-state imaging device according to the present embodiment and a modification of the manufacturing method thereof will be described.

  FIG. 11 shows a modification of the pixel structure of the solid-state imaging device according to this embodiment. As shown in FIG. 11, in the present embodiment, between the color filter 14 and the insulating film 10 on the side surface in the waveguide 12, between the high refractive index layer 13 ′ and the insulating film 10, above the wiring 11. A high refractive index layer 13 may be formed between the planarization layer 15 and the insulating film 10.

  The manufacturing process of the modified example of the pixel structure of the solid-state imaging device according to the present embodiment is performed in the same manner as in the first embodiment. That is, the color filter 14, the high refractive index layer 13 ′, the planarization layer 15, and the microlens 16 are formed on the remaining high refractive index layer 13 without being completely removed.

[Fourth Embodiment]
The fourth embodiment is an example in which the color filter formed in the waveguide is also formed on the insulating film. Here, the description of the same points as in the first embodiment will be omitted, and different points will be described in detail.

[Construction]
First, the pixel structure of the solid-state imaging device according to this embodiment will be described. FIG. 12 is a cross-sectional view of the pixel structure of the solid-state imaging device according to this embodiment.

  As shown in FIG. 12, the pixel structure of the solid-state imaging device according to this embodiment is different from the first embodiment in that the color filter 14 formed in the waveguide 12 is also formed on the insulating film 10. It is a point that has been. That is, the high refractive index layer 13 is formed at the bottom of the waveguide 12, and the color filter 14 is formed on the high refractive index layer 13. Therefore, the inside of the waveguide 12 is embedded with the high refractive index layer 13 / color filter 14, and the color filter 14 is also formed on the insulating film 10 at the periphery of the waveguide 12. Here, the color filter 14 may be in contact with another color filter 14 ′ of an adjacent pixel on the insulating film 10.

[Production method]
Next, a method for manufacturing the pixel structure of the solid-state imaging device according to this embodiment will be described. 13A to 13C are cross-sectional views illustrating a manufacturing process of the pixel structure of the solid-state imaging device according to the present embodiment.

  First, the steps of FIGS. 3A to 3C in the first embodiment are performed.

  Next, as shown in FIG. 13A, the high refractive index layer 13 on the insulating film 10 and in the waveguide 12 is removed. As a result, the high refractive index layer 13 remains only at the bottom of the waveguide 12.

  Next, as shown in FIG. 13B, the color filter 14 is formed on the high refractive index layer 13 in the waveguide 12. The color filter 14 is also formed on the insulating film 10 but remains only in the periphery of the waveguide 12 on the insulating film 10 by lithography. That is, the color filter 14 is formed on the high refractive index layer 13 in the waveguide 12 and on the insulating film 10 in the periphery of the waveguide 12. Here, the color filter 14 may be formed so as to be in contact with another color filter 14 ′ of an adjacent pixel on the insulating film 10.

  Next, as shown in FIG. 13C, the planarizing layer 15 is formed on the entire surface of the color filters 14 and 14 ′ and the insulating film 10.

  Next, as shown in FIG. 12, a microlens 16 is formed on the planarizing layer 15 corresponding to the waveguide 12. In this way, the pixel structure of the solid-state imaging device according to this embodiment is completed.

[effect]
According to the fourth embodiment, the same effect as in the first embodiment can be obtained.

  Furthermore, in the fourth embodiment, when the color filter 14 is formed, etch back is not performed. Thereby, the manufacturing process of a solid-state imaging device can be reduced.

  Note that an antireflection layer 17 may be formed between the high refractive index layer 13 and the color filter 14 in the waveguide 12 of the present embodiment. In this case, the same effect as in the second embodiment can be obtained.

[Modification]
Hereinafter, a pixel structure of the solid-state imaging device according to the present embodiment and a modification of the manufacturing method thereof will be described.

  FIG. 14 shows a modification of the pixel structure of the solid-state imaging device according to this embodiment. As shown in FIG. 14, in this embodiment, between the color filter 14 and the insulating film 10 on the side surface in the waveguide 12 and between the color filters 14 and 14 ′ above the wiring 11 and the insulating film 10. A high refractive index layer 13 may be formed.

  The manufacturing process of the modified example of the pixel structure of the solid-state imaging device according to the present embodiment is performed in the same manner as in the first embodiment. That is, the color filter 14, the planarization layer 15, and the microlens 16 are formed on the remaining high refractive index layer 13 without being completely removed.

[Fifth Embodiment]
The fifth embodiment is a modification of the fourth embodiment, in which the planarizing layer in the fourth embodiment is not formed and the color filter is directly covered with a microlens. Here, the description of the same points as in the fourth embodiment will be omitted, and different points will be described in detail.

[Construction]
First, the pixel structure of the solid-state imaging device according to this embodiment will be described. FIG. 15 is a cross-sectional view of the pixel structure of the solid-state imaging device according to this embodiment.

  As shown in FIG. 15, the pixel structure of the solid-state imaging device according to this embodiment is different from the fourth embodiment in that the planarizing layer 15 is not formed on the color filter 14 and the insulating film 10. Is a point. That is, the inside of the waveguide 12 is embedded by the high refractive index layer 13 / color filter 14, and the microlens 16 is directly formed on the color filter 14 so as to cover the color filter 14. Here, the upper surface of the color filter 14 may protrude above the upper surface of the insulating film 10 as illustrated, or may be the same height as the upper surface of the insulating film 10.

[Production method]
Next, a method for manufacturing the pixel structure of the solid-state imaging device according to this embodiment will be described. FIGS. 16A and 16B are cross-sectional views showing the manufacturing process of the pixel structure of the solid-state imaging device according to this embodiment.

  First, the steps of FIGS. 3A to 3C in the first embodiment are performed.

  Next, as shown in FIG. 16A, the high refractive index layer 13 on the insulating film 10 and in the waveguide 12 is removed. As a result, the high refractive index layer 13 remains only at the bottom of the waveguide 12.

  Next, as shown in FIG. 16B, the color filter 14 is formed on the high refractive index layer 13 in the waveguide 12. The color filter 14 is also formed on the insulating film 10 but is removed by lithography so that the color filter 14 is covered with a microlens 16 to be formed later.

  Next, as shown in FIG. 15, microlenses 16 are directly formed on the color filters 14 and the insulating film 10 corresponding to the waveguides 12. Thereby, the color filter 14 is covered with the microlens 16. In this way, the pixel structure of the solid-state imaging device according to this embodiment is completed.

[effect]
According to the fifth embodiment, the same effect as in the fourth embodiment can be obtained.

  Furthermore, in the fifth embodiment, the planarizing layer 15 is not formed on the color filter 14. Thereby, the manufacturing process of a solid-state imaging device can be reduced as compared with the fourth embodiment.

  Note that an antireflection layer 17 may be formed between the high refractive index layer 13 and the color filter 14 in the waveguide 12 of the present embodiment. In this case, the same effect as in the second embodiment can be obtained.

  Further, the high refractive index layer 13 may be formed between the color filter 14 and the insulating film 10 on the side surface in the waveguide 12 and between the microlens 16 and the insulating film 10 above the wiring 11.

[Sixth Embodiment]
The sixth embodiment is an example in which a color filter formed on a high refractive index layer has a microlens function. Here, the description of the same points as in the first embodiment will be omitted, and different points will be described in detail.

[Construction]
First, the pixel structure of the solid-state imaging device according to this embodiment will be described. FIG. 17 is a cross-sectional view of the pixel structure of the solid-state imaging device according to this embodiment.

  As shown in FIG. 17, the pixel structure of the solid-state imaging device according to this embodiment is different from the first embodiment in that the microlens 16 is not formed and the color filter 14 has the function of the microlens 16. It is. That is, in the present embodiment, the color filter 14 is formed on the high refractive index layer 13 and the insulating film 10 formed at the bottom in the waveguide 12. The color filter 14 continues from the inside of the waveguide 12 to the insulating film 10, and is formed in a convex lens shape on the insulating film 10 corresponding to the waveguide 12. Thereby, the color filter 14 has the same function as the microlens 16 in the first embodiment. Here, the color filter 14 may be in contact with another color filter 14 ′ of an adjacent pixel on the insulating film 10.

[Production method]
Next, a method for manufacturing the pixel structure of the solid-state imaging device according to this embodiment will be described. FIG. 18 is a cross-sectional view of the manufacturing process of the pixel structure of the solid-state imaging device according to this embodiment.

  First, the steps of FIGS. 3A to 3C in the first embodiment are performed.

  Next, as shown in FIG. 18, the high-refractive index layer 13 on the insulating film 10 and in the waveguide 12 is removed. As a result, the high refractive index layer 13 remains only at the bottom in the waveguide 12.

  Next, as shown in FIG. 17, the color filter 14 is formed on the high refractive index layer 13 and the insulating film 10 in the waveguide 12. The color filter 14 is formed in a convex lens shape corresponding to the waveguide 12 on the insulating film 10 by lithography. In this way, the pixel structure of the solid-state imaging device according to this embodiment is completed.

[effect]
According to the sixth embodiment, the same effect as in the first embodiment can be obtained.

  Further, in the present embodiment, after the high refractive index layer 13 is formed at the bottom of the waveguide 12, the color filter 14 is formed on the high refractive index layer 13 and the insulating film 10. Since the color filter 14 is formed in a convex lens shape corresponding to the waveguide 12 on the surface of the insulating film 10, it has the same function as the microlens 16. Thereby, it is not necessary to form the microlens 16 later, and the manufacturing process of the solid-state imaging device can be reduced.

  As shown in FIG. 19, in this embodiment, the protective layer 18 may be formed on the color filter 14 after the color filter 14 is formed. The refractive index of the protective layer 18 is smaller than the refractive index of the color filter 14 and larger than the refractive index in air. Thereby, the reflection of the light by the difference in refractive index can be prevented in the interface of the color filter 14 and air. Furthermore, the surface of the color filter 14 can be protected by forming the protective layer 18.

  Further, an antireflection layer 17 may be formed between the high refractive index layer 13 and the color filter 14 in the waveguide 12 of the present embodiment. In this case, the same effect as in the second embodiment can be obtained.

[Modification]
Hereinafter, a pixel structure of the solid-state imaging device according to the present embodiment and a modification of the manufacturing method thereof will be described.

  FIG. 20 shows a modification of the pixel structure of the solid-state imaging device according to this embodiment. As shown in FIG. 20, in this embodiment, between the color filter 14 and the insulating film 10 on the side surface in the waveguide 12 and between the color filters 14 and 14 ′ above the wiring 11 and the insulating film 10. A high refractive index layer 13 may be formed.

  The manufacturing process of the modified example of the pixel structure of the solid-state imaging device according to the present embodiment is performed in the same manner as in the first embodiment. That is, the color filter 14 is formed on the remaining high refractive index layer 13 without being completely removed, and the color filter 14 is formed in a convex lens shape on the insulating film 10. As described above, the protective layer 18 may be formed on the color filter 14.

  In addition, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention when it is practiced. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be obtained as an invention.

  DESCRIPTION OF SYMBOLS 10 ... Insulating film, 11 ... Wiring, 12 ... Waveguide, 13, 13 ', 50 ... High refractive index layer, 14, 14' ... Color filter, 15 ... Planarization layer, 16 ... Micro lens, 17 ... Antireflection Layer, 18 ... protective layer, 20 ... silicon substrate, 30 ... light receiving part, 40 ... low refractive index layer, 60 ... reflective film.

Claims (5)

A semiconductor substrate;
A light receiving portion formed on the surface of the semiconductor substrate;
A film formed on the semiconductor substrate;
A waveguide formed inside from the surface of the film above the light receiving portion;
A first high refractive index layer formed at the bottom of the waveguide;
A color filter formed in the waveguide on the first high refractive index layer and having a refractive index smaller than that of the first high refractive index layer;
A solid-state imaging device comprising: A microlens formed above the insulating film and the color filter so as to correspond to the waveguide;
A second high refractive index layer formed in the waveguide between the color filter and the microlens and having a refractive index larger than that of the microlens;
The solid-state imaging device according to claim 1, further comprising: An antireflection layer formed in the waveguide between the first high refractive index layer and the color filter, and having a refractive index smaller than the first high refractive index layer and larger than the color filter;
The solid-state imaging device according to claim 1, further comprising:   4. The first high refractive index layer is formed continuously from a bottom portion in the waveguide to a side surface at an upper portion in the waveguide and the insulating film. Solid-state imaging device. A reflective film formed between the first high refractive index layer and the color filter and the film in the waveguide;
The solid-state imaging device according to claim 1, further comprising:

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