JP2012114159A - Solid-state imaging apparatus, method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid-state imaging apparatus which has high sensitivity and suppresses the generation of color mixture, and method for manufacturing the same.SOLUTION: In the solid-state imaging apparatus, division walls 109 are erected on a substrate 101 via an insulating film 107 in the state of having a gap between each other. A lower electrode 110 is formed along an inner wall of a recess part defined by adjacent division walls 109 and a surface of the insulating film 107. Namely the lower electrode 110 is configured that a bottom wall part formed on the surface of the insulating film 107 and a side wall part erected along a side face of the division wall 109 from both edge parts of the bottom wall are integrally formed, and has a recessed sectional shape as a whole. The lower electrode 110 is made from a metal material such as W, Pt or Al, and has light blocking effect. A division wall 109 consists of a metal core part made from W, Al, or Cu, Cr, and an oxide film formed on its outer periphery.

Description

  The present invention relates to a solid-state imaging device and a manufacturing method thereof, and more particularly to a solid-state imaging device including a photoelectric conversion film and a manufacturing method thereof.

  Solid-state imaging devices are widely used as image input units in digital still cameras and mobile phones. In a conventional solid-state imaging device, photodiodes configured by pn junctions are two-dimensionally arranged in a semiconductor substrate.

  By the way, in recent years, with the increase in the number of pixels of the solid-state imaging device, the pixel portion has been miniaturized. When the pixel portion is miniaturized as described above, the area occupied by the photodiode serving as the light receiving portion is reduced, causing problems such as a reduction in sensitivity and a deterioration in color reproducibility.

  To solve such a problem, a solid-state imaging device having a configuration in which a photoelectric conversion film is formed above a semiconductor substrate and photoelectric conversion is performed using the photoelectric conversion film has been proposed (for example, Patent Document 1). The outline of the solid-state imaging device proposed in this document will be described with reference to FIG.

  As shown in FIG. 16, in the surface layer portion of the semiconductor substrate 901, a connection portion 902, a charge storage portion 903, and a reset drain 904 are formed for each region corresponding to a unit pixel. On the semiconductor substrate 901, gate electrodes 905 and 906 are formed via a gate insulating film (not shown), and an insulating film 907 is stacked so as to cover them. On the insulating film 907, a lower electrode 910 is formed for each region corresponding to a unit pixel, and a photoelectric conversion film 911, an upper electrode 912, and a color filter 914 are formed thereon. Each lower electrode 910 is connected to a corresponding connection portion 902 by a contact wiring 908 that passes through the insulating film 907.

  In the light incident from above in the Z-axis direction, the light component of the wavelength filtered by the color filter 914 passes through the upper electrode 912 made of a transparent conductive film and is converted into electric charge by the photoelectric conversion film 911. The converted electric charge is Then, it passes through the contact wiring 908 and is sent to the connection portion 902 and the charge storage portion 903 to be temporarily stored.

  In the solid-state imaging device having such a configuration, the incident light flux is equivalent to the size of the pixel unit, and has a large light receiving unit and higher efficiency than a solid-state imaging device of a type in which a photodiode is formed in a semiconductor substrate. It can be photoelectrically converted.

JP 2009-147067 A

  However, in the solid-state imaging device according to the above-described prior art, there is a problem in that color mixing may occur, thereby causing deterioration in color reproducibility. That is, as shown by the broken line in FIG. 16, when light is incident obliquely, the light that has passed through the green (G) filter 914 is reflected directly or directly to the lower electrode 910 so that the adjacent red (R) Or it will inject into each photoelectric conversion part 911 in a blue (B) unit pixel. This causes a color mixing problem.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a solid-state imaging device capable of suppressing the occurrence of color mixing with high sensitivity and a method for manufacturing the same.

In order to achieve the above object, the present invention has the following features.
The solid-state imaging device according to the present invention is made of a substrate, an insulating film formed on the substrate, and a light-shielding conductive material, and is two-dimensional on the insulating film and spaced from each other A plurality of lower electrodes disposed on the insulating film, and at least a surface thereof is insulative, a partition wall provided between adjacent lower electrodes on the insulating film, and a plurality of lower electrodes in contact with the lower electrode A photoelectric conversion film formed in a state, an upper electrode formed in contact with the photoelectric conversion film on the photoelectric conversion film, and a transmission wavelength corresponding to each lower electrode on the upper electrode. And a plurality of color filters. In the solid-state imaging device according to the present invention, each of the plurality of lower electrodes includes a bottom wall portion formed on the insulating film and a side wall portion attached in a state along the side surface of the partition wall from the edge portion thereof. It is formed integrally and has a concave cross-sectional shape as a whole.

Moreover, the manufacturing method of the solid-state imaging device according to the present invention includes the following steps.
(Step of Forming Insulating Film) An insulating film is formed on the substrate.
(Step of Erecting Partition Walls) On the insulating film, an insulating film is exposed at each bottom portion, and a partition wall that partitions a plurality of recesses arranged two-dimensionally is provided.

(Step of Forming Lower Electrode) Using a light-shielding conductive material, a lower electrode is formed in each recess defined by a partition wall.
(Step of Forming Photoelectric Conversion Film) A photoelectric conversion film is formed on the plurality of lower electrodes in a state in contact with the lower electrode.

(Step of Forming Upper Electrode) An upper electrode is formed on the photoelectric conversion film in contact with the photoelectric conversion film.
(Step of Forming Color Filter) A plurality of color filters having transmission wavelengths corresponding to the respective lower electrodes are formed on the upper electrode.

  In the method of manufacturing the solid-state imaging device according to the present invention including the above steps, in the step of forming the lower electrode, a side wall portion is attached from each edge portion along the side surface of the partition wall, and the lower electrode is insulated. The bottom wall portion in contact with the film and the side wall portion are integrated.

  In the solid-state imaging device according to the present invention, a partition wall is erected so as to partition adjacent lower electrodes, and a side wall portion of the lower electrode is attached in a state along the side surface of the partition wall. For this reason, the obliquely incident light passes through the color filter and is then shielded by the side wall portion of the lower electrode formed along the side wall of the partition wall, even if trying to enter the photoelectric conversion film of the adjacent pixel portion. Therefore, it does not enter the adjacent pixel portion.

  In the solid-state imaging device according to the present invention, since the photoelectric conversion film is formed above the substrate, a high aperture ratio can be realized with respect to the solid-state imaging device including the photodiode formed in the substrate. And high sensitivity.

Therefore, in the solid-state imaging device according to the present invention, it is possible to suppress the occurrence of color mixing with high sensitivity.
In the present invention, “light shielding” includes both absorption and reflection of light, and can prevent or prevent light from entering the photoelectric conversion film of the adjacent pixel portion.

In the solid-state imaging device according to the present invention, the following variations can be adopted as an example.
In the solid-state imaging device according to the present invention, on the premise of the above configuration, the photoelectric conversion film is formed along the side wall portion of each lower electrode and the top portion of the partition wall, and is continuous over the plurality of lower electrodes. It is possible to adopt a configuration that By adopting such a configuration, it is possible to increase the area of the photoelectric conversion film that performs photoelectric conversion, which is excellent from the viewpoint of improving sensitivity.

  In the solid-state imaging device according to the present invention, on the premise of the above configuration, the upper electrode is formed so as to cover the entire photoelectric conversion film and is in a continuous state, and in the region between adjacent partition walls, the lower electrode By being formed along the electrodes, a configuration having a concave cross-sectional shape can be employed. By adopting such a configuration, the incident light can be guided to the photoelectric conversion film in the pixel portion with high efficiency by the shape of the upper electrode or the like having a concave cross-sectional shape.

  In the solid-state imaging device according to the present invention, on the premise of the above-described configuration, it is possible to employ a configuration in which each of the plurality of color filters is formed in a recess formed by the upper electrode in a region between adjacent partition walls. it can. When such a configuration is adopted, the distance from the upper surface of the color filter to the photoelectric conversion film can be shortened as compared with, for example, a planarization film between the upper electrode and the color filter. This is effective in realizing high sensitivity characteristics.

In the solid-state imaging device according to the present invention, on the premise of the above configuration, a configuration in which the ratio between the height and the pitch is 0.5 or more in the partition can be employed.
In the solid-state imaging device according to the present invention, on the premise of the above configuration, a configuration in which the partition wall has a light shielding property can be adopted. As described above, if the partition wall also has light shielding properties, both the side wall portion and the partition wall of the lower electrode have light shielding properties, and color mixture can be prevented more reliably. This is particularly effective when the thickness of the lower electrode is reduced.

  In the solid-state imaging device according to the present invention, on the premise of the above configuration, the partition is configured by a core portion made of a metal material and an insulating film portion made of an insulating material and covering the outer periphery of the core portion. Can be used. When such a configuration is adopted, the degree of freedom in material selection when forming the core portion is increased, which is effective in reducing the manufacturing cost.

  In the solid-state imaging device according to the present invention, on the premise of the above configuration, a configuration in which the cross-sectional shape of the partition wall is a trapezoid whose upper side is shorter than the lower side can be adopted. When such a configuration is adopted, the opening area can be substantially increased, which is effective in improving the sensitivity.

  In the solid-state imaging device according to the present invention, on the premise of the above configuration, a configuration in which the cross-sectional shape of the partition wall is a trapezoid whose upper side is longer than the lower side may be employed. When such a configuration is employed, it is possible to prevent incident light from being reflected by the lower electrode and leaking to the color filter side.

  In the solid-state imaging device according to the present invention, on the premise of the above configuration, a configuration in which the cross-sectional shape of the partition wall is a triangle may be employed. When such a configuration is adopted, the aperture ratio can be further increased as compared with the case where the upper side has a trapezoidal cross-sectional shape shorter than the lower side as described above, which is more effective from the viewpoint of improving sensitivity. It is.

  Further, in the method of manufacturing the solid-state imaging device according to the present invention, in the step of forming the lower electrode, since the side wall portion is attached and formed along the side surface of the partition wall, the occurrence of color mixing is suppressed as described above. A solid-state imaging device can be manufactured efficiently and reliably. In the manufacturing method according to the present invention, since the photoelectric conversion film is formed above the substrate, a solid-state imaging device having high sensitivity can be manufactured.

Therefore, with the method for manufacturing a solid-state imaging device according to the present invention, it is possible to manufacture a solid-state imaging device with high sensitivity and capable of suppressing the occurrence of color mixing.
In the method for manufacturing a solid-state imaging device according to the present invention, the following variation configuration can be employed as an example.

  In the method of manufacturing a solid-state imaging device according to the present invention, on the premise of the above method, in the step of forming the photoelectric conversion film, a plurality of the plurality of lower electrodes are in a state along the side wall portion and the top portion of the partition wall. In the process of forming the photoelectric conversion film in a state continuous over the lower electrode and forming the upper electrode, the upper electrode is formed in a state of covering the entire photoelectric conversion film and in a state of being continuous as a whole. In the region between the adjacent partition walls, the electrode can be formed along the lower electrode, thereby adopting a configuration in which the electrode has a concave cross-sectional shape. In the solid-state imaging device manufactured by such a method, the area of the photoelectric conversion film can be increased, which is effective in realizing a solid-state imaging device having high sensitivity characteristics.

  In the method for manufacturing a solid-state imaging device according to the present invention, on the premise of the above method, in the step of forming a color filter, each of a plurality of color filters is formed in a recess formed by an upper electrode in a region between adjacent partition walls. It is possible to adopt a configuration that does. In the case of adopting such a configuration, the shape of the upper electrode or the like having a concave cross-sectional shape can guide incident light to the photoelectric conversion film in the pixel portion with high efficiency, preventing high sensitivity and color mixing. A solid-state imaging device that can be reliably achieved can be more reliably manufactured.

It is a schematic block diagram which shows the structure of the solid-state imaging device 1 which concerns on Embodiment 1 of this invention. 3 is a schematic cross-sectional view showing a part of a pixel 100 of a pixel array 10 in the solid-state imaging device 1 extracted. It is a schematic cross section for showing the relationship between the height of the partition 109 and the pitch. 3 is a schematic plan view showing the shape of a partition wall 109. FIG. 3 is a schematic cross-sectional view showing a partial process in the manufacturing process of the solid-state imaging device 1. FIG. 3 is a schematic cross-sectional view showing a partial process in the manufacturing process of the solid-state imaging device 1. FIG. 3 is a schematic cross-sectional view showing a partial process in the manufacturing process of the solid-state imaging device 1. FIG. (A) is a schematic plan view which shows the shape of the partition 209 which concerns on the modification 1, (b) is a schematic plan view which shows the shape of the partition 219 which concerns on the modification 2, (c) is a deformation | transformation. FIG. 9D is a schematic plan view showing a shape of a partition wall 229 according to Example 3, and (d) is a schematic plan view showing a shape of a partition wall 239 according to Modification Example 4. (A) is a schematic cross-sectional view showing a partial pixel 300 portion of the solid-state imaging device according to the second embodiment, and (b) is a partial pixel 350 portion of the solid-state imaging device according to the third embodiment. It is a schematic cross section which extracts and shows. (A) is a schematic cross section which shows the shape of the partition 379 which concerns on the modification 5, (b) is a schematic cross section which shows the shape of the partition 389 concerning the modification 6, (c) is a deformation | transformation. 10 is a schematic cross-sectional view showing the shape of a partition wall 399 according to Example 7. FIG. (A) is a schematic cross-sectional view showing a part of the pixel 400 of the solid-state imaging device according to the fourth embodiment, and (b) is a part of the pixel 450 of the solid-state imaging device according to the fifth embodiment. It is a schematic cross section which extracts and shows. FIG. 11 is a schematic cross-sectional view showing a part of a pixel 600 portion of a solid-state imaging device according to a sixth embodiment. (A) is a schematic plan view which shows the shape of the partition 619 which concerns on the modification 8, (b) is a schematic cross section which shows the shape of the partition 629 which concerns on the modification 9, (c) is a deformation | transformation. 14 is a schematic cross-sectional view showing the shape of a partition wall 639 according to Example 10. FIG. 14 is a schematic plan view illustrating a configuration of a pixel array of a solid-state imaging device according to Modification Example 11. FIG. FIG. 16 is a schematic cross-sectional view showing a form of a partition wall 709 according to Modification 12. It is a schematic cross section which extracts and shows a part pixel part of the solid-state imaging device concerning a prior art.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Each of the following embodiments is an example used for easily explaining the configuration of the present invention and the operations and effects produced therefrom, and the present invention is not limited to the following essential features. The form is not limited.

[Embodiment 1]
1. Overall Configuration of Solid-State Imaging Device 1 The overall configuration of the solid-state imaging device 1 according to Embodiment 1 will be described with reference to FIG.

  As shown in FIG. 1, in the solid-state imaging device 1 according to the first embodiment, a plurality of pixel units 100 are arranged in a matrix (matrix) in the XY plane direction, thereby forming a pixel array 10. Yes. A pulse generation circuit 21, a vertical shift register 22, and a horizontal shift register 23 are connected to the pixel array 10.

2. Configuration of Pixel Array 10 The configuration of the pixel array 10 will be described with reference to FIGS. FIG. 2 is a schematic cross-sectional view showing a region corresponding to a part of the pixel units 100 in the pixel array 10.

  As shown in FIG. 2, in the pixel array 10 of the solid-state imaging device 1, in each pixel unit 100, a connection unit 102, a charge storage unit 103, and a reset drain are sequentially formed on the surface layer portion of the semiconductor substrate 101 from the right side in the X axis direction. 104 is formed. Further, gate electrodes 105 and 106 are formed on the surface of the semiconductor substrate 101 with a gate insulating film (not shown) interposed therebetween. The gate electrode 105 is formed in a region corresponding to between the connection portion 102 and the charge storage portion 103, and the gate electrode 106 is formed in a region corresponding to between the charge storage portion 103 and the reset drain 104.

  A lower electrode 110 is formed on the semiconductor substrate 101 on which the gate electrodes 105 and 106 are formed with an insulating film 107 interposed therebetween. A partition 109 extending upward in the Z-axis direction is erected in a boundary region between adjacent pixel portions 100. The lower electrode 110 is connected to a connection portion 102 formed in the semiconductor substrate 101 by a contact wiring 108 that passes through the insulating film 107.

  As shown in FIG. 2, in the lower electrode 110, a bottom wall portion formed on the surface of the insulating film 107 and a side wall portion attached in a state along the side surface of the partition wall 109 are integrated. As a whole, it has a concave cross-sectional shape (a U-shaped cross-sectional shape). Specifically, as shown in FIG. 3, the lower electrode 110 is formed on the insulating film 107, and is attached along the side wall of the partition wall 109 and the bottom wall portion 110 a connected to the contact wiring. The side wall portion 110b is integrally formed. The lower electrode 110 is partitioned for each pixel unit 100 by the partition 109.

The partition wall 109 is formed of a metal core part made of a metal material and an oxide film part made of metal oxide covering the surface. Specifically, as shown in a portion surrounded by a two-dot chain line in FIG. 3, the partition wall 109 covers the metal core body portion 1091 made of a metal material and the periphery thereof, and the metal material of the metal core body portion 1091 is oxidized. The oxide film portion 1092 is made of a material, and the oxide film portion 1092 ensures electrical insulation between the lower electrodes 110 between the adjacent pixel portions 100. The oxide film portion 1092 is not limited to the surface of the metal core portion 1091 that is oxidized, and may be a silicon oxide film or the like formed separately from the metal core portion 1091. In the case where a silicon oxide film is formed as the oxide film portion 1092, it can be formed using a silicon process to have a desired film thickness necessary for ensuring insulation, thereby improving reliability. it can.
For this reason, at least the surface of the partition wall 109 is insulative.

  As shown in FIG. 2, a photoelectric conversion film 111 is formed over the entire surface of the lower electrode 110 and the top of the partition wall 109. An upper electrode 112 made of a transparent conductive material is stacked on the surface of the photoelectric conversion film 111. Here, the lower electrode 110 and the photoelectric conversion film 111 are in contact with each other, and the photoelectric conversion film 111 and the upper electrode 112 are also in contact with each other.

  The upper electrode 112 also has a concave shape in the region between adjacent barrier ribs 109, and a planarization film 113 is formed so as to fill the concave portion. A color filter 114 is formed on the planarized surface of the planarizing film 113. The color filter 114 has a wavelength range that is transmitted corresponding to each pixel unit 100. For example, as illustrated in FIG. 2, the pixel unit 100 that transmits a light component in the red (R) wavelength range, and green The pixel unit 100 transmits a light component in the wavelength region of (G) and the pixel unit 100 transmits a light component in the wavelength region of blue (B). In FIG. 2, for convenience, the pixel portions are illustrated in the order of red (R), green (G), and blue (B). However, the actual arrangement order is different from this. There is also a case.

Here, each of the constituent parts in the solid-state imaging device 1 is formed using the following materials.
Lower electrode 110; metal material such as W, Pt, Al (a light-shielding material is desirable)
Upper electrode 112; visible range transparent metal (Au, Ag, Pt, Cu, Rh, Pd, Al, Cr, etc.), visible range transparent inorganic conductive oxide (In ₂ O ₃ , SnO ₂ , ITO (indium tin) Oxide), ZnO, TiO ₂ , CdO, CdIn ₂ O ₄ , Cd ₂ SnO ₂ , Zn ₂ SO ₄ , In ₂ O ₃ —ZnO, etc.), visible range transparent spinel compounds (MgInO ₄ , CaGaO _4, etc.) ), Visible transparent nitride (TiN, ZrN, HfN, etc.), visible transparent boride (LaB6, etc.), visible transparent conductive polymer material, partition wall 109; Low metal (W, Al, Cu, Cr, etc.), and as a material of the film portion, the metal oxide photoelectric conversion film 111; compound semiconductor (amorphous silicon (amorphous silicon), gas) Such as Umm arsenic)
2. Size of Each Part The size of each part included in the pixel array 10 in the solid-state imaging device 1 will be described with reference to FIGS. The following sizes are as follows when the size of the pixel unit 100 is assumed to be 3 [μm].

Film thickness of the lower electrode 110: about 0.15 [μm] Film thickness of the photoelectric conversion film 111: about 0.5 [μm] Film thickness of the upper electrode 112: about 0.3 [μm] Film thickness of the planarizing film 113 About 0.3 [μm] film thickness of the color filter 114; about 0.8 [μm] As shown in FIG. 3, the height d of the partition wall 109 is about 1.5 [μm], and the width Is about 0.3 [μm]. Further, the height d, the unit pixel pitch p, and the aspect ratio d / p of the partition wall 109 are 0.5 or more, more preferably 1 or more.

3. Planar Shape of Partition 109 The planar shape of the partition 109 will be described with reference to FIG. FIG. 4 is a schematic plan view showing a part of the partition wall 109 extracted.

  As shown in FIG. 4, in the solid-state imaging device 1 according to the present embodiment, the partition walls 109 in the pixel array 10 have a lattice shape, and the lower electrode 110 is formed in each opening 109a.

4). Superiority In the solid-state imaging device 1 according to the present embodiment, the partition wall 109 is erected so as to partition the lower electrodes 110 of the adjacent pixel units 100, and the side wall portion 110 b of the lower electrode 110 is It is attached along the side surface of the partition wall 109. For this reason, as shown in FIG. 2, the obliquely incident light passes through the color filter 114 and then enters the photoelectric conversion film 111 of the adjacent pixel unit 100, and then along the side surface of the partition wall 109. Since the light is shielded by the side wall portion 110 a of the formed lower electrode 110, it does not enter the adjacent pixel portion 100.

  In the present embodiment, since the metal core body portion 1091 of the partition wall 109 is formed of a metal having low light transmittance (W, Al, Cu, Cr, etc.) as described above, the partition wall 109 also prevents color mixing.

  Moreover, in the solid-state imaging device 1, since the photoelectric conversion film 111 is formed above the semiconductor substrate 101, a high aperture ratio can be realized with respect to the solid-state imaging device including a photodiode formed in the substrate. it can. Furthermore, in the configuration of the conventional solid-state imaging device, the solid-state imaging device 1 according to the present embodiment is capable of receiving light that is obliquely incident on the photoelectric conversion film of the pixel and is reflected without contributing to photoelectric conversion. By re-entering the photoelectric conversion film on the side of the partition wall 109, it contributes to the photoelectric conversion and has high sensitivity.

Therefore, the solid-state imaging device according to the present invention has high sensitivity and high color reproducibility by suppressing the occurrence of color mixing.
5. Manufacturing Method A manufacturing method of the solid-state imaging device 1 according to the present embodiment, in particular, a manufacturing method of the pixel array 10 will be described with reference to FIGS.

  As shown in FIG. 5A, the surface layer portion of the semiconductor substrate 101 is doped with impurities, and the connection portion 102, the charge storage portion 103, and the reset drain 104 correspond to each pixel portion 100. Form. Then, after forming a gate insulating film (not shown) on the surface of the semiconductor substrate 101, gate electrodes 105 and 106 are formed thereon. Then, an insulating film 107 is formed so as to cover the gate electrodes 105 and 106 and the gate insulating film, and a contact wiring 108 is formed in each portion corresponding to the upper portion of the connection portion 102. The contact wiring 108 is opened in a corresponding portion of the insulating film 107 by using a lithography technique and an anisotropic dry etching technique typified by RIE, and, for example, a blanket CVD method is used for the opening. (W) It can be formed by embedding metal.

  On the insulating film 107, a partition wall preparation film 1090 using a metal (W, Al, Cu, Cr, or the like) that is a material of the partition wall 109 is formed. The partition wall preparation film 1090 is formed using a sputtering method, a CVD method, or the like so that the film thickness becomes 1.5 [μm]. In the case where W is used as the material of the partition wall preparation film 1090, a method of growing a film using a CVD method after forming a seed using a sputtering method can be employed.

  Next, as shown in FIG. 5B, a photoresist 500 is formed on the barrier rib preparation film 1090. The photoresist 500 is formed at a position where the partition 109 is to be formed with a width of 0.3 [μm].

  Next, as shown in FIG. 5C, etching is performed to remove the photoresist 500, whereby the partition 109 is completed. Between the adjacent partitions 109, an opening 109a is formed. Then, the top portion 108 a of the contact wiring 108 is exposed at the bottom of the recess formed by the adjacent partition 109 and the surface of the insulating film 107.

  As shown in FIG. 3, the partition wall 109 is composed of a metal core body portion 1091 and an oxide film portion 1092 covering the surface thereof. In the manufacturing process, the surface of the partition wall 109 is naturally removed after the photoresist 500 is removed. Oxidation or oxidation treatment, or formation of an oxide film by CVD or the like forms an oxide film portion 1092 that covers the surface. Here, when natural oxidation or oxidation treatment is performed, an oxide film is also formed on the top portion of the contact wiring 108, but thereafter, the top portion 108 a of the contact wiring 108 is partially exposed so as to be exposed. The formed oxide film is removed.

  Next, as illustrated in FIG. 5D, an electrode preparation film 1100 is formed so as to cover the surface of the partition 109 and the surface of the insulating film 107. The electrode preparation film 1100 is formed using the constituent material of the lower electrode 110.

  Next, as shown in FIG. 6A, when the electrode preparation film 1100 is etched, a photoresist 501 having an opening in a portion corresponding to the upper portion of the partition wall 109 is formed. Then, as shown in FIG. 6B, the electrode preparation film 1100 at the top of the partition wall 109 is removed by performing etching, and the lower electrode 110 is completed.

  Next, as illustrated in FIG. 6C, the photoelectric conversion film 111 is formed on the lower electrode 110. As described above, the photoelectric conversion film 111 can be formed from amorphous silicon, gallium arsenide, or the like by using, for example, a plasma CVD method or an organic vapor deposition method (MOCVD method).

  Next, as shown in FIG. 7A, the upper electrode 112 is formed on the photoelectric conversion film 111. The upper electrode 112 can be formed by forming an ITO film or the like using, for example, a DC magnetron sputtering apparatus.

  Next, as shown in FIG. 7B, a planarizing film 113 is formed on the upper electrode 112 from an acrylic resin material using, for example, a coating method. Thereby, the upper surface where the color filter 114 is to be formed is flattened.

As shown in FIG. 7C, a color filter 114 having a transmission wavelength corresponding to each pixel unit 100 is formed on the planarizing film 113 to complete the pixel array 10 of the solid-state imaging device 1.
Note that although an example in which a light-blocking metal is used as a material for the partition wall 109 in this embodiment mode, an insulating material such as an opaque resin can be used as a matter of course. In the case of using an opaque resin, in order to obtain a sufficient light shielding property, if Al, Pt, W, etc. having excellent light shielding properties are used as the lower electrode film, a thickness of about 0.15 [μm] It is possible to sufficiently prevent color mixture between pixel portions, which is an object of the present invention. Further, as described above, the partial oxide film formed so that the top portion 108a of the contact wiring 108 is exposed after the oxide film portion 1092 covering the surface of the metal core portion 1091 in the present embodiment is formed. The removal step is unnecessary.

[Modification 1]
The form of the partition 209 according to Modification 1 will be described with reference to FIG.
As shown in FIG. 8A, the partition wall 209 according to the first modification has a form that defines a rectangular opening 209a that is long in the X-axis direction. That is, the solid-state imaging device including the partition wall 209 according to the first modification includes a plurality of rectangular pixel portions that are longer in the X-axis direction than in the Y-axis direction.

Even when the partition 209 having such a configuration is provided, the same effects as those of the solid-state imaging device 1 according to the first embodiment can be obtained.
[Modification 2]
The form of the partition 219 according to Modification 2 will be described with reference to FIG.

  As shown in FIG. 8B, the partition wall 219 according to the modified example 2 has a form that partitions a substantially circular opening 219 a. That is, the solid-state imaging device including the partition wall 219 according to the second modification includes a plurality of pixel portions having a circular planar shape.

Even when the partition wall 219 having such a configuration is provided, the same effects as those of the solid-state imaging device 1 according to Embodiment 1 can be obtained.
[Modification 3]
The form of the partition 229 according to Modification 3 will be described with reference to FIG.

  As shown in FIG.8 (c), the partition 229 which concerns on the modification 3 has a form which divides the octagonal opening part 229a. That is, the solid-state imaging device including the partition wall 229 according to the third modification includes a plurality of pixel units having an octagonal planar shape.

Even when the partition wall 229 having such a configuration is provided, the same effects as those of the solid-state imaging device 1 according to Embodiment 1 can be obtained.
[Modification 4]
The form of the partition wall 239 according to Modification 4 will be described with reference to FIG.

  As shown in FIG. 8D, the partition wall 239 according to the modification 4 has a configuration in which an elliptical or oval opening 239a is defined. That is, the solid-state imaging device including the partition wall 239 according to the fourth modification includes a plurality of pixel units having an elliptical or oval planar shape.

Even when the partition wall 239 having such a configuration is provided, the same effect as that of the solid-state imaging device 1 according to Embodiment 1 can be obtained.
[Embodiment 2]
The configuration of the pixel array according to Embodiment 2 will be described with reference to FIG. Also in FIG. 9A, a region corresponding to a part of the pixel units 300 is extracted from the configuration of the pixel array.

  As shown in FIG. 9A, on the insulating film 107, a partition wall 309 is erected at the boundary portion between the adjacent pixel portions 300, and the lower electrode 310 is related to the first embodiment. Similar to the lower electrode 110, it is formed to have a concave cross-sectional shape along the surface of the insulating film 107 and the side surface of the partition 309. Further, the photoelectric conversion film 311, the upper electrode 312, the planarization film 313, and the color filter 314 are the same as those in the first embodiment.

The pixel array according to this embodiment is characterized in that the cross-sectional shape of the partition wall 309 is a trapezoidal cross-sectional shape whose upper side is narrower than the lower side.
For example, in manufacturing, according to a lithography method using KrF excimer laser light, a narrow line pattern with a width of about 0.2 [μm] can be formed, and a partition as a light shielding wall is formed by etching. If the photoresist is etched isotropically, the width of the upper side in the cross section of the partition 309 can be made 0.1 [μm] or less. In addition, since the width of the bottom side of the partition wall 309 is about 0.2 [μm], it is possible to avoid the problem that the partition wall 309 collapses.

  When the structure of the partition 309 according to this embodiment is employed, the width of the partition 309 on the light incident side (upper Z-axis direction) can be reduced, so that even in a mode in which the size of the pixel portion 300 is small, Sensitivity can be improved.

  Note that in the case of the solid-state imaging device according to this embodiment, in order to separate the lower electrode 310 for each pixel portion 300, a photoresist is embedded in the opening instead of the step of etching the partition wall 309, and the like. Is etched so that only the top portion of the partition 309 can be exposed, and the partition 309 having an upper end with a fine width less than the resolution of the lithography technique can be formed. Of course, an oxide film or the like can be embedded and planarized by a CMP method or the like.

Further, the top portion of each partition 309 and each corner portion can have a curvature.
[Embodiment 3]
The configuration of the pixel array according to Embodiment 3 will be described with reference to FIG. Also in FIG. 9B, a region corresponding to a part of the pixel portions 350 is extracted from the configuration of the pixel array.

  As shown in FIG. 9B, in the pixel array of the solid-state imaging device according to the third embodiment, the partition wall 359 erected on the insulating film 107 has a trapezoidal cross-sectional shape whose upper side is wider than the lower side. is there. The lower electrode 360, the photoelectric conversion film 361, and the upper electrode 362 are formed along the surface of the insulating film 107 and the side surface of the partition 359. A planarizing film 363 and a color filter 364 are formed thereon.

  The solid-state imaging device according to this embodiment is characterized in that the partition wall 359 has a trapezoidal cross-sectional shape whose upper side is wider than the lower side. In the case where the partition wall 359 having such a form is employed, light that is obliquely incident on the pixel portion and passes through the photoelectric conversion film 361 without contributing to photoelectric conversion is reflected on the surface of the lower electrode 360 and further photoelectric conversion is performed. The light that passes through the photoelectric conversion film 361 without contributing to the light can re-enter the photoelectric conversion film 361 formed on the side wall of the partition wall 359, thereby contributing to photoelectric conversion again. Further, the light reflected by the side wall portion of the lower electrode 360 (the portion attached along the side surface of the partition wall 359) or the partition wall 359 is irradiated downward in the Z-axis direction, and converted into electric charges by the photoelectric conversion film 361. The For this reason, the incident light can be converted into electric charges with high efficiency and has high sensitivity characteristics. The same effect as that of the solid-state imaging device 1 according to the first embodiment can be obtained.

  In addition, since the distance between the upper surfaces of the partition walls 359 can be increased, the light that has passed through the color filter of the adjacent pixel portion at the pixel portion boundary is reflected or absorbed by the upper surfaces of the partition walls 359, thereby improving the color resolution. There is.

[Modification 5]
The form of the partition 379 according to Modification 5 will be described with reference to FIG.
As shown in FIG. 10A, the partition wall 379 according to the modification 5 has a curved upper corner portion (a portion indicated by an arrow A) in the cross section.

  In the solid-state imaging device including the partition wall 379 having such a configuration, the photoelectric conversion film and the upper electrode that are stacked also on the upper portion (top portion) of the partition wall 379 are stacked on the upper corner portion of the partition wall 379. Is formed with a curvature, it is possible to prevent the photoelectric conversion film and the upper electrode from being disconnected. Even in the case of this modification, the same effects as those of the solid-state imaging device 1 according to the first embodiment can be obtained.

[Modification 6]
The form of the partition 389 according to Modification 6 will be described with reference to FIG.
As shown in FIG. 10 (b), the partition wall 389 according to the modification 6 has a skirt portion whose curvature is processed in the cross section (portion indicated by an arrow B).

  In the solid-state imaging device including the partition wall 389 having such a configuration, the photoelectric conversion film and the upper electrode stacked on the bottom portion of the partition wall 389 are prevented from being disconnected. Even in the case of this modification, the same effects as those of the solid-state imaging device 1 according to the first embodiment can be obtained.

[Modification 7]
The form of the partition wall 399 according to Modification 7 will be described with reference to FIG.
As shown in FIG. 10 (c), the partition wall 399 according to the modified example 7 has both the upper corner portion and the skirt portion curved in the cross section (portions indicated by arrows C and D).

  In the solid-state imaging device including the partition wall 399 having such a configuration, in the upper corner portion and the bottom portion of the partition wall 399, the photoelectric conversion film and the upper electrode stacked thereon are suppressed from being disconnected. Even in the case of this modification, the same effects as those of the solid-state imaging device 1 according to the first embodiment can be obtained.

[Embodiment 4]
The configuration of the pixel array of the solid-state imaging device according to Embodiment 4 will be described with reference to FIG. FIG. 11A is a schematic cross-sectional view illustrating a part of the pixel portion 400 in the pixel array.

  As shown in FIG. 11A, also in the solid-state imaging device according to the present embodiment, a partition wall 109 is erected on the insulating film 107 at a boundary portion between adjacent pixel portions 400, and thus formed. A lower electrode 110, a photoelectric conversion film 111, and an upper electrode 112 are formed in the inner portion of the recess. The configuration so far is the same as that of the solid-state imaging device 1 according to the first embodiment.

  In the solid-state imaging device according to the present embodiment, each color filter 414 is embedded and formed in a state where it is in contact with the upper electrode 112 in a region formed in the region between adjacent partition walls 109 due to the standing of the partition walls 109. It has the main features.

  In the solid-state imaging device according to the present embodiment, by adopting the above-described configuration, the distance from the surface of the semiconductor substrate 101 to the surface of the color filter 414 can be shortened, and the oblique incident light to the adjacent pixel unit 400 is obtained. This is superior from the viewpoint of preventing color mixing associated with the intrusion of water. For this reason, in the solid-state imaging device according to the present embodiment, it is possible to propagate even more intensely incident light to the desired photoelectric conversion film 111 and to further improve the color resolution.

  In the configuration of the present embodiment, the distance from the surface of the semiconductor substrate 101 to the surface of the color filter 414 is, for example, about 0.7 [μm] as compared with the solid-state imaging device 1 according to the first embodiment. Can be shortened.

[Embodiment 5]
The configuration of the pixel array of the solid-state imaging device according to Embodiment 5 will be described with reference to FIG. FIG. 11B is a schematic cross-sectional view illustrating a part of the pixel portion 450 extracted from the pixel array.

  As shown in FIG. 11B, in the pixel array of the solid-state imaging device according to the present embodiment, the configuration of the color filter 464 is different from that of the solid-state imaging device according to the fourth embodiment. Specifically, in the solid-state imaging device according to the present embodiment, the color filter 464 completely covers the upper electrode 112 including the portion corresponding to the top portion of the partition wall 109.

  In the solid-state imaging device according to this embodiment that employs such a configuration, incident light is reliably transmitted through the color filter 464 and then incident on the photoelectric conversion film 111. Specifically, in the solid-state imaging device according to Embodiment 4 shown in FIG. 11A, a part of the incident light propagates directly through the upper electrode 112 made of a transparent conductive film. It is considered as a possibility that the light enters the photoelectric conversion film 111.

  On the other hand, in the solid-state imaging device according to the present embodiment shown in FIG. 11B, the color filter 464 is formed on the entire upper electrode 112, so that the incident light is reliably colored. After passing through the filter 464, it enters the photoelectric conversion film 111.

Therefore, in the solid-state imaging device according to the present embodiment, in addition to the effects of the fourth embodiment, higher color reproducibility can be realized.
[Embodiment 6]
The configuration of the pixel array of the solid-state imaging device according to Embodiment 6 will be described with reference to FIG. FIG. 12 is a schematic cross-sectional view illustrating one pixel portion 600 extracted from the pixel array.

  As shown in FIG. 12, in the pixel array of the solid-state imaging device according to this embodiment, one pixel unit 600 is divided into three regions E, F, and G by a partition wall 609 erected on the insulating film 107. It is partitioned. In each of the regions E, F, and G, the lower electrode 110 is separated from each other, and a connection portion 102, a charge storage portion 103, a reset drain 104, and the like are provided correspondingly.

The color filter 614 has a single color filter configuration through the three regions E, F, and G.
Here, in the partition 609 according to this embodiment, when the size of the pixel portion 600 is about 6 [μm], the width of the partition is about 0.3 [μm] and the height is about 2.5 [μm]. .

  In the solid-state imaging device according to the present embodiment, since one pixel unit 600 is divided into three regions by the partition 609, oblique incident light reaches the partition 609 or its side surface in each region E, F, and G. The light is reflected by the side wall portion of the provided lower electrode 110 and reenters the photoelectric conversion film 111. Therefore, in the solid-state imaging device according to the present embodiment, high photoelectric conversion efficiency can be obtained and high sensitivity characteristics can be obtained.

[Modification 8]
The form of the partition 619 according to Modification 8 will be described with reference to FIG.
As shown in FIG. 13A, the partition wall 619 according to the modified example 8 has a form that partitions three rectangular openings 619a that are each long in the Y-axis direction. That is, in the solid-state imaging device according to Modification Example 8, one pixel portion is divided into three regions (corresponding to the opening portions 619a) in the X-axis direction.

  Even when the partition wall 619 having such a configuration is provided, the same effects as those of the solid-state imaging device according to Embodiment 6 can be obtained. That is, it is effective for light obliquely incident in the X-axis direction.

[Modification 9]
The form of the partition 629 according to Modification 9 will be described with reference to FIG.
As shown in FIG. 13B, the partition wall 629 according to the modified example 9 has a form in which three rectangular openings 629a each extending in the X-axis direction are partitioned. That is, in the solid-state imaging device according to Modification Example 8, one pixel unit is divided into three regions (corresponding to the opening 629a, respectively) in the Y-axis direction.

  Even when the partition 629 having such a configuration is provided, the same effects as those of the solid-state imaging device according to Embodiment 6 can be obtained. That is, it is effective for light obliquely incident in the Y-axis direction.

[Modification 10]
The form of the partition 639 according to Modification 10 will be described with reference to FIG.
As shown in FIG. 13C, the partition wall 639 according to the modified example 10 has a form that partitions nine openings 639a arranged in a matrix. That is, in the solid-state imaging device according to Modification Example 10, one pixel unit is divided into nine regions (corresponding to the opening 639a, respectively) in the X-axis direction and the Y-axis direction.

  Even when the partition wall 639 having such a configuration is provided, the same effects as those of the solid-state imaging device according to Embodiment 6 can be obtained. That is, it is effective for light incident obliquely from both the X-axis direction and the Y-axis direction.

[Modification 11]
The configuration of the pixel array 60 of the solid-state imaging device according to Modification 11 will be described with reference to FIG. In FIG. 14, nine pixel portions 600 a to 600 i in the configuration of the pixel array 60 are extracted and schematically illustrated.

  As shown in FIG. 14, the pixel portion 600 a disposed at the center of the pixel array 60 is not provided with a partition that divides the inside of the pixel portion 600 a. Thereby, a wide opening area can be secured. In addition, since it is arranged at the center of the pixel array 60, the problem of obliquely incident light hardly occurs.

  Next, in the pixel portions 600b and 600c arranged at the left and right edge portions in the X-axis direction with respect to the pixel portion 600a, each of the pixel portions 600b and 600c has a partition wall (the solid lines in the pixel portions 600b and 600c are Partition into four regions each in the X-axis direction. In the pixel portions 600b and 600c, photoelectric conversion is effectively performed on the light incident obliquely in the X-axis direction as described above.

  In addition, in the pixel portions 600d and 600e disposed at the upper and lower edge portions in the Y-axis direction with respect to the pixel portion 600a, each pixel portion 600d and 600e is divided into four regions in the Y-axis direction by partition walls. Has been. In the pixel portions 600d and 600e, photoelectric conversion is effectively performed on the light incident obliquely in the Y-axis direction as described above.

  Further, in the pixel portions 600f, 600g, 600h, and 600i arranged at the four corner portions of the pixel array 60, the pixel portions 600f, 600g, 600h, and 600i are partitioned into four regions obliquely by partition walls. . In the pixel portions 600f, 600g, 600h, and 600i, photoelectric conversion is effectively performed as described above with respect to light incident in a direction oblique to both the X axis and the Y axis.

  In the present modification, the above-described configuration is adopted for the eight pixel portions 600b to 600i arranged on the outer edge portion of the pixel array 60 by forming partition walls in the pixels. The pixel portion arranged in the region between each of the pixel portion 600a and the pixel portions 600b to 600i arranged at the outer edge portion may also be configured to appropriately divide the region by the partition wall.

[Modification 12]
The form of the partition 709 according to Modification 12 will be described with reference to FIG.
As shown in FIG. 15, the partition 709 according to this modification is a metal core body portion 7091 whose core portion is made of metal, and is combined with an oxide film portion 7092 that covers the periphery thereof. It is configured. In the partition wall 709 according to this modification, the metal core body portion 7091 is made of the same metal material as that of the metal core body section 1091 of the partition wall 109 according to the first embodiment. The film portion 7092 is composed of silicon oxide.

  The partition 709 according to the present modification also has an insulating surface and can insulate between adjacent lower electrodes, so that the same effect as the solid-state imaging device 1 of the first embodiment can be obtained. Obtainable.

Note that the portion covering the periphery of the metal core portion 7091 can be made of silicon nitride, and in this case, the same effect can be obtained.
[Other matters]
In the first to sixth embodiments and the first to twelfth modifications, the pixel portion array of the pixel array is a matrix shape as an example. However, the present invention is not limited to this. For example, a honeycomb-like arrangement can be used.

The size as an example above can be changed as appropriate.
In addition, the partition wall does not necessarily have a two-layer structure of a metal core part and an oxide film part covering the surface, and graphite, SiO, SiN, black resist, or the like can be used. There is no need to have light shielding properties.

  Further, by further providing a microlens on the color filter, the sensitivity can be further improved.

  The present invention is useful for realizing a solid-state imaging device having high sensitivity characteristics and high color reproducibility as an image input unit of a digital still camera, a cellular phone, or the like.

1. Solid-state imaging device 10,60. Pixel array 21. Pulse generation circuit 22. Vertical shift register 23. Horizontal shift register 100, 300, 350, 400, 450, 600, 600a to 600i. Pixel unit 101. Substrate 102. Connection unit 103. Charge storage unit 104. Reset drain 105,106. Gate electrode 107. Insulating film 108. Contact wiring 109,209,219,229,239,309,359,379,389,399,609,619,629,639,709. Partition 110, 310, 360. Lower electrode 111,311,361. Photoelectric conversion film 112 312 362. Upper electrode 113,313,363. Planarizing film 114, 314, 364, 414, 464, 614. Color filter 500, 501. Photoresist 1090. Partition wall preparation film 1091, 7091. Metal core part 1092, 7092. Oxide film portion 1100. Electrode preparation membrane

Claims (14)

A substrate,
An insulating film formed on the substrate;
A plurality of lower electrodes two-dimensionally arranged in a state of being spaced apart from each other, made of a conductive material having a light-shielding property,
At least the surface thereof has an insulating property, and on the insulating film, a partition wall is provided between the adjacent lower electrodes, and
On the plurality of lower electrodes, a photoelectric conversion film formed in contact with the lower electrodes;
On the photoelectric conversion film, an upper electrode formed in contact with the photoelectric conversion film,
On the upper electrode, a plurality of color filters formed at positions corresponding to each lower electrode,
With
Each of the plurality of lower electrodes is formed integrally with a bottom wall portion formed on the insulating film, and a side wall portion attached in a state along the side surface of the partition wall from an edge thereof. A solid-state imaging device characterized by having a concave cross-sectional shape as a whole. The photoelectric conversion film is formed in a state along the side wall portion and the top portion of the partition wall in each of the lower electrodes, and is continuous over the plurality of lower electrodes. The solid-state imaging device described in 1. The upper electrode is formed so as to cover the whole of the photoelectric conversion film and is in a continuous state, and is formed along the lower electrode in a region between adjacent partition walls, thereby forming a concave. The solid-state imaging device according to claim 2, having a cross-sectional shape. 4. The solid-state imaging device according to claim 3, wherein each of the plurality of color filters is formed in a recess formed by the upper electrode in a region between the adjacent partition walls. The solid-state imaging device according to any one of claims 1 to 4, wherein the partition wall has a height to pitch ratio of 0.5 or more. The solid-state imaging device according to any one of claims 1 to 5, wherein the partition wall has a light shielding property. The solid-state imaging device according to any one of claims 1 to 5, wherein at least a surface of the partition wall has light reflectivity. The said partition is comprised from the core part which consists of metal materials, and the insulation coating part which consists of an insulating material and coat | covers the outer periphery of the said core part. The any one of Claims 1-7 characterized by the above-mentioned. The solid-state imaging device described in 1. The solid-state imaging device according to any one of claims 1 to 8, wherein the partition wall has a trapezoidal cross-sectional shape whose upper side is shorter than the lower side. The solid-state imaging device according to any one of claims 1 to 8, wherein the partition wall has a trapezoidal cross-sectional shape whose upper side is longer than the lower side. The solid-state imaging device according to any one of claims 1 to 8, wherein the partition wall has a triangular cross-sectional shape. Forming an insulating film on the substrate;
On the insulating film, the insulating film is exposed at the bottom of each of the insulating films, and a partition wall that divides a plurality of two-dimensionally arranged recesses is erected,
Using a conductive material having a light shielding property, forming a lower electrode in each recess defined by the partition; and
Forming a photoelectric conversion film in contact with the lower electrode on the plurality of lower electrodes;
Forming an upper electrode on the photoelectric conversion film in contact with the photoelectric conversion film;
Forming a plurality of color filters on the upper electrode at positions respectively corresponding to the plurality of lower electrodes;
With
In the step of forming the lower electrode, from each edge, a side wall portion is attached in a state along the side surface of the partition wall,
In the lower electrode, the bottom wall portion in contact with the insulating film and the side wall portion are integrated. In the step of forming the photoelectric conversion film, the photoelectric conversion is performed in a state along the side wall portion and the top portion of the partition wall in each lower electrode and in a state continuous over the plurality of lower electrodes. Forming a film,
In the step of forming the upper electrode, the upper electrode is formed in a state of covering the whole of the photoelectric conversion film and being continuous as a whole,
The method of manufacturing a solid-state imaging device according to claim 12, wherein the upper electrode has a concave cross-sectional shape by being formed along the lower electrode in a region between adjacent partition walls. 14. The solid-state imaging according to claim 13, wherein, in the step of forming the color filter, each of the plurality of color filters is formed in a recess formed by the upper electrode in a region between the adjacent partition walls. Device manufacturing method.

Images