JP2015157370A - Substrate equipped with organic functional layer and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate equipped with an organic functional layer having a protective film excellent in stability under a high temperature and high humidity environment without causing loss due to reflection light, and to provide method for producing the same.SOLUTION: There is provided a substrate equipped with an organic functional layer which has a base material, an organic functional layer disposed on the base material and a protective film disposed on the organic functional layer. The protective film has a plurality of silicon oxynitride layers and the absolute value of the refractive index difference between the silicon oxynitride layers is 0.1 or less. In the protective film, the silicon oxynitride layer on a side far from the organic functional layer of the plurality of silicon oxynitride layers has a film thickness of 50 nm or more and the density is larger by 0.05 (g/cm) or more than the density of the silicon oxynitride layer formed on a position closest to the organic functional layer.

Description

  The present invention relates to a substrate with an organic functional layer having a protective film for protecting the organic functional layer and a method for producing the same, and more particularly, a substrate with an organic functional layer applicable to a color filter, an image sensor, an organic solar battery, an organic EL, and the like. It relates to the manufacturing method.

  Conventionally, a color imaging device using an organic photoelectric conversion layer has been proposed. A conventional color imaging device includes a pixel electrode formed on a semiconductor substrate on which a signal readout circuit is formed, an organic photoelectric conversion layer formed on the pixel electrode, and a counter electrode ( An upper electrode), a protective film formed on the counter electrode and protecting the counter electrode, a color filter, and the like. The protective film is composed of a SiOxNy film formed by a plasma CVD method. Various types of such protective films have been conventionally proposed (see Patent Documents 1 and 2).

  Patent Document 1 describes an imaging device having an organic photoelectric conversion layer that uses a silicon oxynitride film (SiOxNy film) formed by a plasma CVD method as a protective film for protecting a counter electrode.

Patent Document 2 discloses a gas barrier in which a solvent-resistant layer (acrylic cured resin), a cardo polymer layer (epoxy cured resin), and a silicon oxynitride layer are formed in this order on both surfaces of a polyimide film. A film is described. It is described that this silicon oxynitride layer is formed by a plasma CVD method.
In addition, a SiOxNy layer is formed as a gas barrier layer by sputtering on a solvent resistant layer (acrylic cured resin), a cardo polymer layer is formed thereon, and a silicon oxynitride layer is formed on the cardo polymer layer. A gas barrier film formed of is described.

JP 2013-118363 A JP 2009-241483 A

As described above, Patent Documents 1 and 2 describe the film composition and gas barrier properties of the SiOxNy film used as the protective film. However, when the SiOxNy film is used as, for example, a protective film for an imaging device or the like, it is necessary to optimize the optical path length by setting the film thickness of the SiOxNy film to about 200 nm in order to suppress reflection of incident light and prevent a decrease in sensitivity. is there. For this reason, the SiOxNy film does not have a degree of freedom in film thickness, and it is difficult to design to suppress film peeling simply by reducing the film thickness.
In addition, Patent Documents 1 and 2 do not indicate any stability of the SiOxNy film at high temperature and high humidity, and do not consider wet heat storage stability.
At present, there is no SiOxNy film used as a protective film that has no loss due to reflected light and that does not deteriorate the gas barrier performance even in a high temperature and high humidity environment.

  An object of the present invention is to solve the problems based on the above-mentioned conventional technology, and to provide a substrate with an organic functional layer having a protective film that has no loss due to reflected light and has excellent stability in a high temperature and high humidity environment, and its production It is to provide a method.

In order to achieve the above object, a first aspect of the present invention includes a base material, an organic functional layer disposed on the base material, and a protective film disposed on the organic functional layer. Has a plurality of silicon oxynitride layers, and each silicon oxynitride layer has a refractive index difference in absolute value of 0.1 or less, preferably 0.05 or less, and the protective film includes a plurality of silicon oxynitride layers. The silicon oxynitride layer far from the organic functional layer has a thickness of 50 nm or more, and the density is 0.05 (g / g) higher than the density of the silicon oxynitride layer formed closest to the organic functional layer. The present invention provides a substrate with an organic functional layer characterized by being larger than cm ³ ).

The protective film may have another layer between the silicon oxynitride layers. For example, the organic functional layer has a heat resistance of 245 ° C. or lower.
For example, the organic functional layer is an organic photoelectric conversion layer that generates charges when irradiated with light, and the organic photoelectric conversion layer is provided with a lower electrode on the substrate side and a transparent upper electrode on the opposite side of the substrate It is preferable that a protective film is disposed on the upper electrode.
Further, for example, the organic functional layer is a color filter layer containing an organic substance, and a protective film is disposed on the color filter layer.

The second aspect of the present invention includes a protective film forming step of forming a plurality of silicon oxynitride layers as a protective film on the organic functional layer disposed on the base material by using a plasma CVD method. In the film formation step, the silicon oxynitride layer far from the organic functional layer is positioned closest to the organic functional layer by changing at least one of the pressure during deposition and the high frequency power among the film forming conditions in the plasma CVD method. The present invention provides a method for producing a substrate with an organic functional layer, wherein the substrate is formed to have a density of 0.05 (g / cm ³ ) or more larger than the density of the formed silicon oxynitride layer. For example, the organic functional layer has a heat resistance of 245 ° C. or lower.

ADVANTAGE OF THE INVENTION According to this invention, the board | substrate with an organic functional layer which can suppress the loss by reflected light and has a protective film excellent in stability in a high temperature, high humidity environment can be provided. In particular, when an organic photoelectric conversion layer is used for the organic functional layer, sensitivity loss due to reflected light can be reduced.
Further, according to the present invention, it is possible to manufacture a substrate with an organic functional layer having a protective film that can suppress loss due to reflected light and has excellent stability in a high temperature and high humidity environment.

(A) is a schematic diagram which shows the board | substrate with an organic functional layer of embodiment of this invention, (b) is a schematic diagram which shows the other example of the board | substrate with an organic functional layer of embodiment of this invention, (C) is a schematic diagram which shows the state before a protective film is formed in the board | substrate with an organic functional layer of Fig.1 (a). (A) is a schematic diagram which shows the 1st modification of the board | substrate with an organic functional layer of embodiment of this invention, (b) is the 2nd modification of the board | substrate with an organic functional layer of embodiment of this invention. It is a schematic diagram which shows an example, (c) is a schematic diagram which shows the 3rd modification of the board | substrate with an organic functional layer of embodiment of this invention. (A) is typical sectional drawing which shows the image sensor of embodiment of this invention, (b) is typical sectional drawing which shows the other example of the image sensor of embodiment of this invention. (A) And (b) is typical sectional drawing which shows the manufacturing method of the image pick-up element of embodiment of this invention in order of a process. (A) And (b) is typical sectional drawing which shows the manufacturing method of the image pick-up element of embodiment of this invention in order of a process, and shows the post process of FIG.4 (b). (A) is typical sectional drawing which shows the organic solar cell of embodiment of this invention, (b) is typical sectional drawing which shows the organic EL element of embodiment of this invention. (A) And (b) is typical sectional drawing for demonstrating the stress which acts on the thin film each formed in the board | substrate. It is a schematic diagram which shows the measuring apparatus which measures the curvature amount of the board | substrate with which the thin film was formed.

Hereinafter, a substrate with an organic functional layer and a method for producing the same according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
FIG. 1A is a schematic diagram illustrating a substrate with an organic functional layer according to an embodiment of the present invention, and FIG. 1B is a schematic diagram illustrating another example of the substrate with an organic functional layer according to an embodiment of the present invention. FIG. 2C is a schematic diagram showing a state before a protective film is formed on the substrate with an organic functional layer in FIG.

As shown in FIG. 1A, the substrate 10 with an organic functional layer has a base material 12, an organic functional layer 14, and a protective film 16.
The substrate 12 supports the organic functional layer 14 and the protective film 16. The base material 12 can support the organic functional layer 14 and the protective film 16 and has a predetermined strength against heat and the like applied when the organic functional layer 14 and the protective film 16 are produced. For example, it is composed of a flat plate. As the substrate 12, for example, a glass substrate, a metal substrate with an insulating layer, a resin substrate, or the like can be used. In addition, about the base material 12, according to the kind etc. of the organic functional layer 14, a conductive or insulating base material can be used suitably.

The organic functional layer 14 includes an organic substance and exhibits a predetermined function. Examples of the organic functional layer 14 include an organic photoelectric conversion layer used for an image sensor, a photoelectric conversion layer containing an organic substance used for an organic solar cell, an organic EL layer used for an organic EL, and a color filter.
The organic functional layer 14 is used in the form of a single element such as a color filter, an organic photoelectric conversion layer used for an image sensor, a photoelectric conversion layer containing an organic substance used for an organic solar cell, and an organic EL layer. Are used. The organic functional layer 14 has, for example, heat resistance of 245 ° C. or lower.

  Here, the heat resistance is a temperature at which the function of the organic functional layer 14 can be maintained, and is a temperature at which the function of the organic functional layer 14 is impaired. For example, in the case of a color filter, it is a temperature at which the original spectral characteristics change due to problems such as changes in transmittance and color. In the case of an organic photoelectric conversion layer, it is a temperature at which performance degradation such as increase in dark current occurs. If it is an organic EL layer, it is the temperature at which the emission intensity decreases. The heat resistance of 245 ° C. or lower means that when the temperature exceeds 245 ° C., the function of the organic functional layer 14 as described above is impaired.

The protective film 16 is for protecting the organic functional layer 14. The protective film 16 has a function of protecting the organic functional layer 14 for a long time in a high temperature and high humidity environment, and functions as a barrier film.
The protective film 16 is a multilayer structure in which a plurality of silicon oxynitride layers represented by SiOxNy are stacked. In the example shown in FIG. 1A, the protective film 16 is a first silicon oxynitride layer 16a and a second silicon oxynitride layer 16b. However, the number of layers is not particularly limited. In addition, the protective film 16 in FIG. 1A is directly provided on the organic functional layer 14, but the arrangement of the protective film 16 is limited to this as long as the organic functional layer 14 can be protected. is not. For example, an electrode, a transparent electrode, another component or structure, etc. may be provided on the organic functional layer 14, and the protective film 16 may be provided on the electrode or other component or structure.

  In the protective film 16, the plurality of silicon oxynitride layers all have different compositions. In the silicon oxynitride layer constituting the protective film 16, x and y of SiOxNy are 0.5 ≦ x ≦ 1.0 and −2.2y + 2.1 ≦ x ≦ −2.2y + 2.41 (0.5 ≦ It is preferable to satisfy y ≦ 0.86). More preferably, 0.5 ≦ x ≦ 1.0 and −2.2y + 2.1 ≦ x ≦ −2.2y + 2.32 are satisfied.

The protective film 16 is 2.20 (g / cm ³ ) ≦ ρ ≦ 2.60 (g / cm ³ ), where the density is ρ (g / cm ³ ). Preferably, 2.30 (g / cm ³ ) ≦ ρ ≦ 2.60 (g / cm ³ ).
If the density ρ (g / cm ³ ) is in the above range, the protective film 16 has a predetermined heat resistance and can protect the organic functional layer 14. If the density of the protective film 16 is less than 2.20 (g / cm ³ ), predetermined heat resistance cannot be obtained. On the other hand, when the density of the protective film 16 exceeds 2.60 (g / cm ³ ), the film stress of the protective film 16 becomes high and adversely affects the lower organic functional layer 14.

In the protective film 16, the plurality of silicon oxynitride layers have different densities, and the silicon oxynitride layer on the side farther from the organic functional layer 14 among the plurality of silicon oxynitride layers is closest to the organic functional layer. 0.05 (g / cm ³ ) or greater than the density of the silicon oxynitride layer formed at the position. Specifically, in the case of FIG. 1A, the first silicon oxynitride layer 16a is formed directly on the organic functional layer 14, and the second silicon oxynitride layer 16b is formed on the organic functional layer 14. This corresponds to the silicon oxynitride layer on the side far from the surface. In the case of FIG. 1A, when comparing the second silicon oxynitride layer 16b and the first silicon oxynitride layer 16a, the density of the _second silicon oxynitride layer 16b is ρ2, and the first acid when the density of the silicon nitride layer 16a and [rho _1, it is ^{_{ρ 1 +0.05 (g / cm 3}} ) ≦ ρ 2.

In the case of two or more layers, the density of the silicon oxynitride layer differs depending on the relative positional relationship with respect to the organic functional layer 14, and the density is at least 0.05 (g / cm ³ ) or higher in order from the organic functional layer 14 side.

For example, when the protective film 16 has a three-layer structure of a first silicon oxynitride layer 16a to a third silicon oxynitride layer 17 as in the substrate 10a with an organic functional layer shown in FIG. Of the silicon oxynitride layer 16a to the third silicon oxynitride layer 17, the uppermost third silicon oxynitride layer 17 has the highest density within the range of the above composition. However, the present invention is not limited to this, and in the case of three or more layers, the density of the first silicon oxynitride layer 16a and the second silicon oxynitride layer 16b satisfies the above range, and the first silicon oxynitride If the function of the protective film 16 can be exhibited by the layer 16a and the second silicon oxynitride layer 16b, the uppermost third silicon oxynitride layer 17 has a density lower than that of the second silicon oxynitride layer 16b. .05 (g / cm ³ ) or more, and the density range may not be satisfied.

On the contrary, the second silicon oxynitride layer 16b and the uppermost third silicon oxynitride layer 17 satisfy the above composition, and the second silicon oxynitride layer 16b and the uppermost third silicon oxynitride layer 17 If the function of the protective film 16 can be exhibited at 17, the density of the first silicon oxynitride layer 16 a needs to be 0.05 (g / cm ³ ) or less than that of the second silicon oxynitride layer 16 b. The density range may not be satisfied.
Further, the protective film 16 does not need to be the uppermost layer of the substrate with an organic functional layer, and a film may be further formed on the protective film 16. In this case, the configuration, density and composition of the film are not particularly limited.

With respect to SiOxNy, the protective film 16 is a silicon oxynitride layer that is transparent and has a stable film quality by being in the above composition range. Moreover, the refractive index is in the range of 1.65 to 1.75.
Here, the term “transparent” means that the light absorption rate is less than 0.2% in the wavelength range of 400 to 800 nm (visible light range). That is, the term “transparent” means that the light absorption rate in the wavelength range of 400 to 800 nm is a maximum value of less than 0.2%. If the light absorption rate in the visible light region is 0.2%, light absorption can be ignored.
When the protective film 16 is out of the above composition range, it is not transparent and the refractive index does not fall within the range of 1.65 to 1.75. “Not transparent” means that the light absorption rate in the visible light region is 0.2% or more.

  In the protective film 16, each silicon oxynitride layer has a refractive index difference within 0.1 in absolute value. Specifically, in the example shown in FIG. 1A, the refractive index difference between the first silicon oxynitride layer 16a and the second silicon oxynitride layer 16b is within an absolute value of 0.1, preferably 0.8. It is within 05. When the number of protective films 16 is three or more, the refractive index difference of all the silicon oxynitride layers is within 0.1, preferably within 0.05 in absolute value. That is, in the protective film 16, the difference between the maximum value and the minimum value of the refractive index of the silicon oxynitride layer is within 0.1, preferably within 0.05. Thereby, reflection of the incident light L at the interface between the first silicon oxynitride layer 16a and the second silicon oxynitride layer 16b of the protective film 16 can be suppressed, and loss due to the reflected light can be suppressed. The difference in refractive index is more preferably within 0.03 in absolute value.

The protective film 16 represented by SiOxNy is formed by a plasma CVD method at a predetermined substrate temperature (film formation temperature) in a reaction chamber such as a process chamber, for example. By using the plasma CVD method, it is possible to form a film at a higher film formation rate than the vapor deposition method or the like.
In the substrate 10 with an organic functional layer in FIG. 1A, for example, as shown in FIG. 1C, after forming the organic functional layer 14 on the base material 12, the protective film 16 is formed on the organic functional layer 14. As described above, a silicon oxynitride layer having the above composition is formed using a plasma CVD method at a predetermined substrate temperature (film formation temperature). Regarding the composition and density of the silicon oxynitride layer, the silicon oxynitride layer is formed in advance by changing the flow rate of the reaction gas, and the film formation conditions (film formation temperature (substrate temperature), pressure in the reaction chamber during film formation ( (Hereinafter referred to as pressure during film formation), high-frequency power during film formation, gas type (SiH ₄ , NH ₃ , N ₂ O), gas mixing ratio, etc.) A silicon nitride layer can be formed.
In forming the protective film 16, the heat resistance of the organic functional layer 14 is taken into consideration. If the heat resistance of the organic functional layer 14 is 245 ° C. or lower, the substrate temperature (deposition temperature) when forming the protective film 16 is 245 ° C. or lower.

In the protective film 16, a plurality of silicon oxynitride layers are formed, each having a different density. In this case, the silicon oxynitride layer formed at the position closest to the organic functional layer 14 by changing at least one of the pressure at the time of film formation and the high-frequency power among the film formation conditions in the plasma CVD method. 0.05 (g / cm ³ ) or more can be made larger than the density. In forming a plurality of silicon oxynitride layers, a plurality of silicon oxynitride layers are continuously formed by changing at least one of the pressure during deposition and the high-frequency power, which is a deposition condition, without stopping the supply of the source gas. May be. Alternatively, a plurality of silicon oxynitride layers may be continuously formed by stopping the supply of the source gas and changing at least one of the pressure during film formation and the high frequency power. As described above, a plurality of silicon oxynitride layers can be formed by changing the density of the silicon oxynitride layer only by changing at least one of the pressure at the time of film formation and the high frequency power. Only one process chamber is required to form the substrate. For this reason, the time required for loading and unloading of the base material and the film forming atmosphere becomes unnecessary, and an increase in the film forming time of the protective film can be suppressed, and the production cost can be reduced.

In the present embodiment, as in the substrate 10b with an organic functional layer shown in FIG. 2A, another component layer 19 is provided between the first silicon oxynitride layer 16a and the second silicon oxynitride layer 16b. There may be (other layers). Further, as in the substrate 10c with an organic functional layer shown in FIG. 2B, there is another component layer 19 on the second silicon oxynitride layer 16b, that is, outside the second silicon oxynitride layer 16b. May be. Furthermore, there is another component layer 19 between the first silicon oxynitride layer 16a and the second silicon oxynitride layer 16b as in the substrate 10d with an organic functional layer shown in FIG. There may be another component layer 19 outside the protective film 16.
The other constituent layer 19 (other layer) is, for example, a transparent electrode, a resin layer, or an adhesive layer.
The configurations of the organic functional layer-attached substrates 10b to 10d shown in FIGS. 2A to 2C can also be applied to the organic functional layer-provided substrate 10a shown in FIG. 1B.
In the present invention, the total thickness is preferably 50 nm or more regardless of the configuration of the protective film 16. Of the protective film 16, at least the silicon oxynitride layer far from the organic functional layer 14 has a thickness of 50 nm or more.

Further, the density of the silicon oxynitride layer can be changed in the protective film 16, whereby the film stress of the protective film 16 can be adjusted. The film stress and its measuring method will be described in detail later. The film stress of the protective film 16 is a stress value in the multilayer structure. Even if the protective film has a structure in which another constituent layer 19 is present between the silicon oxynitride layers as shown in FIGS. 2A to 2C, the film stress is the value of the stress in the state of the multilayer structure. It is.
The protective film 16 preferably has an overall film stress of −5 MPa to −220 MPa (compressive stress). When the density difference and the refractive index difference are in the above ranges, the entire film stress is in the above range. Within the range of the entire film stress, even if the protective film 16 is partially exposed to a process using an organic solvent in the subsequent step, peeling or wrinkling does not occur.

Hereinafter, the specific example of the board | substrate with an organic functional layer of this invention is demonstrated. Specifically, the substrate with an organic functional layer of the present invention can be called, for example, an organic CMOS.
FIG. 3A is a schematic cross-sectional view showing an image sensor according to an embodiment of the present invention, and FIG. 3B is a schematic cross-sectional view showing another example of the image sensor according to the embodiment of the present invention.
The image pickup device 20 shown in FIG. 3A is called an organic CMOS, and converts a visible light image into an electric signal. The imaging device 20 includes a substrate 30, an insulating layer 32, a pixel electrode (lower electrode) 34, an organic layer 36, a counter electrode (upper electrode) 38, a protective film (sealing layer) 40, and a color filter 42. And a partition wall 44, a light shielding layer 46, and an overcoat layer 48. A reading circuit 60 and a counter electrode voltage supply unit 62 are formed on the substrate 30.

The board | substrate 30 is corresponded to the base material 12 (refer Fig.1 (a)) of this invention. As the substrate 30, for example, a glass substrate or a semiconductor substrate such as Si is used. An insulating layer 32 made of a known insulating material is formed on the substrate 30. A plurality of pixel electrodes 34 are formed on the surface of the insulating layer 32. The pixel electrodes 34 are arranged in a matrix on the surface 32a of the insulating layer 32, for example.
A first connection portion 64 that connects the pixel electrode 34 and the readout circuit 60 is formed in the insulating layer 32. Further, a second connection portion 66 that connects the counter electrode 38 and the counter electrode voltage supply unit 62 is formed. The second connection part 66 is formed at a position not connected to the pixel electrode 34 and the organic layer 36. The first connection part 64 and the second connection part 66 are made of a conductive material.

Inside the insulating layer 32, a wiring layer 68 made of a conductive material for connecting the readout circuit 60 and the counter electrode voltage supply unit 62 to, for example, the outside of the imaging element 20 is formed.
As described above, the circuit board 35 is formed by forming the pixel electrodes 34 connected to the first connection portions 64 on the surface 32 a of the insulating layer 32 on the substrate 30. The circuit board 35 is also referred to as a CMOS substrate.

An organic layer 36 is formed so as to cover the plurality of pixel electrodes 34 and avoid the second connection portion 66, and the organic layer 36 is formed across the plurality of pixel electrodes 34. The organic layer 36 receives incident light L including at least visible light and generates electric charges according to the amount of light, and includes a photoelectric conversion layer 52 and an electron blocking layer 50.
In the organic layer 36, the electron blocking layer 50 is formed on the pixel electrode 34 side, and the photoelectric conversion layer 52 is formed on the surface 50 a of the electron blocking layer 50. The organic layer 36 may be a single photoelectric conversion layer 52 without providing the electron blocking layer 50.

The electron blocking layer 50 is a layer for suppressing injection of electrons from the pixel electrode 34 to the photoelectric conversion layer 52.
The photoelectric conversion layer 52 generates charges according to the amount of incident light L, for example, received light such as visible light. The photoelectric conversion layer 52 is an organic photoelectric conversion layer mainly composed of an organic material, and is formed on the electron blocking layer 50 across the plurality of pixel electrodes 34.
As long as the photoelectric conversion layer 52 and the electron blocking layer 50 have a constant film thickness on the pixel electrode 34, the film thickness may not be constant otherwise. In this case, the film thickness is a thickness in a region where the film thickness is constant. The photoelectric conversion layer 52 will be described in detail later.

The counter electrode 38 is an electrode facing the pixel electrode 34, and is provided so as to cover the photoelectric conversion layer 52. A photoelectric conversion layer 52 is provided between the pixel electrode 34 and the counter electrode 38.
The counter electrode 38 is made of a conductive material that is transparent to the incident light L (light including at least visible light) in order to make light incident on the photoelectric conversion layer 52. The counter electrode 38 is electrically connected to the second connection portion 66 disposed outside the photoelectric conversion layer 52, and is connected to the counter electrode voltage supply portion 62 via the second connection portion 66. Yes.

  Examples of the material of the counter electrode 38 include metals, metal oxides, metal nitrides, metal borides, organic conductive compounds, and mixtures thereof. Specific examples include tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), indium tungsten oxide (IWO), conductive metal oxides such as titanium oxide, and metal nitrides such as TiN. Metal, gold (Au), platinum (Pt), silver (Ag), chromium (Cr), nickel (Ni), aluminum (Al), etc., and a mixture or laminate of these metals and conductive metal oxides Products, organic conductive compounds such as polyaniline, polythiophene, and polypyrrole, and laminates of these with ITO. Particularly preferable materials for the transparent conductive film are ITO, IZO, tin oxide, antimony-doped tin oxide (ATO), fluorine-doped tin oxide (FTO), zinc oxide, antimony-doped zinc oxide (AZO), gallium-doped zinc oxide ( GZO). A particularly preferable material among the materials of the counter electrode 38 is ITO.

The light transmittance of the counter electrode 38 is preferably 60% or more, more preferably 80% or more, more preferably 90% or more, and more preferably 95% or more in the visible light wavelength.
The counter electrode 38 preferably has a thickness of 5 to 30 nm. By making the counter electrode 38 have a thickness of 5 nm or more, the lower layer can be sufficiently covered, and uniform performance can be obtained. On the other hand, if the thickness of the counter electrode 38 exceeds 30 nm, the counter electrode 38 and the pixel electrode 34 may be locally short-circuited, resulting in an increase in dark current. The local short circuit occurs when the counter electrode 38 is made of ITO by sputtering, and when the film thickness exceeds 30 nm, plasma damage increases. However, the occurrence of a local short circuit can be suppressed by setting the thickness of the counter electrode 38 to 30 nm or less.

  The counter electrode voltage supply unit 62 applies a predetermined voltage to the counter electrode 38 via the second connection unit 66. When the voltage to be applied to the counter electrode 38 is higher than the power supply voltage of the image sensor 20, the power supply voltage is boosted by a booster circuit such as a charge pump to supply the predetermined voltage.

  The pixel electrode 34 is an electrode for collecting charges for collecting charges generated in the photoelectric conversion layer 52. The pixel electrode 34 is connected to the readout circuit 60 via the first connection portion 64. The readout circuit 60 is provided on the substrate 30 corresponding to each of the plurality of pixel electrodes 34, and reads out a signal corresponding to the charge collected by the corresponding pixel electrode 34.

  Examples of the material of the pixel electrode 34 include metals, conductive metal oxides, metal nitrides and borides, organic conductive compounds, and mixtures thereof. Specific examples include tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), indium tungsten oxide (IWO), conductive metal oxides such as titanium oxide, and titanium nitride (TiN). , Conductive metal nitrides such as molybdenum nitride, tantalum nitride, tungsten nitride, metals such as gold (Au), platinum (Pt), silver (Ag), chromium (Cr), nickel (Ni), aluminum (Al), Furthermore, mixtures or laminates of these metals and conductive metal oxides, organic conductive compounds such as polyaniline, polythiophene and polypyrrole, laminates of these with ITO, and the like can be mentioned. Particularly preferable materials for the transparent conductive film are ITO, IZO, tin oxide, antimony-doped tin oxide (ATO), fluorine-doped tin oxide (FTO), zinc oxide, antimony-doped zinc oxide (AZO), gallium-doped zinc oxide ( GZO). Among the materials of the pixel electrode 34, a particularly preferable material is any one of titanium nitride, molybdenum nitride, tantalum nitride, and tungsten nitride.

The readout circuit 60 is constituted by, for example, a CCD, a MOS circuit, a TFT circuit, or the like, and is shielded from light by a light shielding layer (not shown) provided in the insulating layer 32. The readout circuit 60 is preferably a CMOS circuit from the viewpoint of noise and high speed.
Although not shown, for example, a high-concentration n region surrounded by a p region is formed on the substrate 30, and the first connection portion 64 is connected to the n region. A read circuit 60 is provided in the p region. The n region functions as a charge storage unit that stores the charge of the photoelectric conversion layer 52. The signal charge accumulated in the n region is converted into a signal corresponding to the amount of charge by the readout circuit 60 and output to the outside of the image sensor 20 or the like via the wiring layer 68, for example.

In the image sensor 20, the organic layer 36 corresponds to the organic functional layer of the present invention. The protective film 40 is formed so as to cover the counter electrode 38. The protective film 40 is not directly provided on the organic layer 36. However, the protective film 40 can protect the organic layer 36 including the photoelectric conversion layer 52 from deterioration factors such as water molecules and oxygen. The organic layer 36 has a heat resistance of 245 ° C. or lower, for example.
The protective film 40 protects the organic layer 36 by preventing entry of factors that degrade the organic photoelectric conversion material contained in a solution such as an organic solvent, plasma, or the like in each manufacturing process of the imaging element 20. Further, after the image pickup device 20 is manufactured, the intrusion of factors that deteriorate the organic photoelectric conversion material such as water molecules and oxygen is prevented, and the deterioration of the organic layer 36 is prevented during long-term storage and long-term use. . Further, when the protective film 40 is formed, the already formed organic layer 36 is not deteriorated. Further, the incident light L reaches the organic layer 36 through the protective film 40. For this reason, the protective film 40 is transparent to light having a wavelength detected by the organic layer 36, for example, visible light.

The protective film 40 is the same multilayer structure as the protective film 16 described above. The protective film 40 has the same composition and density as the protective film 16 described above, and is formed by forming two silicon oxynitride layers represented by SiOxNy. The protective film 40 is formed by laminating a first silicon oxynitride layer 41a and a second silicon oxynitride layer 41b. The protective film 40 is formed by a plasma CVD method at a predetermined substrate temperature (film formation temperature), for example, at a temperature of 245 ° C. or lower.
For example, the protective film 40 has a total film thickness of 50 to 500 nm.
If the total film thickness of the protective film 40 is less than 50 nm, the barrier property may be lowered, or the resistance of the color filter to the developer may be lowered. On the other hand, when the total thickness of the protective film 40 exceeds 500 nm, it is difficult to suppress color mixing when the pixel size is less than 1 μm. Even in this case, the thickness of the second silicon oxynitride layer 41b far from the organic layer 36 in the protective film 40 is 50 nm or more.

  For example, in the imaging device 20 having a pixel size of less than 2 μm, particularly about 1 μm, if the distance between the color filter 42 and the photoelectric conversion layer 52, that is, the total film thickness of the protective film 40 is thick, The influence of the oblique incident component of the incident light (visible light) may increase, and color mixing may occur. For this reason, it is preferable that the total film thickness of the protective film 40 is thinner.

The color filter 42 is formed at a position facing each pixel electrode 34 on the protective film 40. The partition wall 44 is provided between the color filters 42 on the protective film 40 and is for improving the light transmission efficiency of the color filter 42. The light shielding layer 46 is formed in a region other than the region (effective pixel region) where the color filter 42 and the partition wall 44 are provided on the protective film 40, and light is incident on the photoelectric conversion layer 52 formed outside the effective pixel region. Is to prevent. The color filter 42, the partition wall 44, and the light shielding layer 46 are formed by, for example, a photolithography method.
Although the color filter 42 is provided, the color filter 42 may not be provided. In this case, since the partition wall 44 and the light shielding layer 46 are not provided in addition to the color filter 42, the protective film 40 is the uppermost layer. The protective film 40 may also have a configuration in which another constituent layer is provided between the first silicon oxynitride layer 41a and the second silicon oxynitride layer 41b, similarly to the protective film 16 described above.

The overcoat layer 48 is for protecting the color filter 42 from subsequent processes and is formed so as to cover the color filter 42, the partition wall 44 and the light shielding layer 46.
In the image sensor 20, one pixel electrode 34, on which the organic layer 36, the counter electrode 38, and the color filter 42 are provided, is a unit pixel.

  For the overcoat layer 48, a polymer material such as an acrylic resin, a polysiloxane resin, a polystyrene resin, and a fluorine resin, or an inorganic material such as silicon oxide and silicon nitride can be used as appropriate. When a photosensitive resin such as polystyrene is used, the overcoat layer 48 can be patterned by a photolithography method, so that it is used as a photoresist when opening the peripheral light shielding layer, sealing layer, insulating layer, etc. on the bonding pad. The overcoat layer 48 itself is preferably processed as a microlens, which is preferable. On the other hand, it is also possible to use the overcoat layer 48 as an antireflection layer, and it is also preferable to form various low refractive index materials used as the partition walls of the color filter 42. In addition, in order to pursue a function as a protective layer and a function as an antireflection layer with respect to a subsequent process, the overcoat layer 48 can be configured to have two or more layers combining the above materials.

  The color filter 42 contains an organic substance and corresponds to the organic functional layer of the present invention. For this reason, the overcoat layer 48 is formed by forming two silicon oxynitride layers represented by SiOxNy having the same composition and density as the above-described protective film 16, similarly to the above-described protective film 40. Also good. In this case, the overcoat layer 48 may be formed by laminating the first silicon oxynitride layer 48a and the second silicon oxynitride layer 48b as in the imaging device 20a shown in FIG. 3B. . The imaging device 20a shown in FIG. 3B is the same component except that the configuration of the overcoat layer 48 is different from that of the imaging device 20 shown in FIG. Description is omitted.

The imaging element 20 can protect the organic layer 36 by the protective film 40 for a long time even in a severe environment of high temperature and high humidity such as a temperature of 85 ° C. and a relative humidity of 85%. For this reason, the image sensor 20 can be used without degrading performance for a long time even in the above-mentioned severe environment of high temperature and high humidity. For this reason, the image sensor 20 is suitable for applications where the use environment is severe such as a monitoring camera.
Further, the protective film 40 has a difference in refractive index within 0.1, preferably within 0.05, so that the generation of reflected light is suppressed, and the sensitivity loss in the image sensor 20 is small. Thereby, the efficiency of the image sensor 20 can be increased. The efficiency in this case is the ratio of the amount of light actually incident on the internal photoelectric conversion layer 52 to the amount of light from the outside incident on the image sensor. Light reflection or light absorption at the protective film 40 causes a reduction in efficiency.

  In the present embodiment, the pixel electrode 34 is configured to be formed on the surface of the insulating layer 32, but is not limited thereto, and may be configured to be embedded in the surface portion of the insulating layer 32. In addition, the second connection portion 66 and one counter electrode voltage supply portion 62 are provided, but a plurality of the second connection portion 66 and the counter electrode voltage supply portion 62 may be provided. For example, a voltage drop at the counter electrode 38 can be suppressed by supplying a voltage from both ends of the counter electrode 38 to the counter electrode 38. The number of sets of the second connection portion 66 and the counter electrode voltage supply portion 62 may be appropriately increased or decreased in consideration of the chip area of the element.

Next, the photoelectric conversion layer 52 and the electron blocking layer 50 constituting the organic layer 36 will be described in more detail.
The photoelectric conversion layer 52 includes a p-type organic semiconductor material and an n-type organic semiconductor material. Exciton dissociation efficiency can be increased by joining a p-type organic semiconductor material and an n-type organic semiconductor material to form a donor-acceptor interface. For this reason, the photoelectric conversion layer of the structure which joined the p-type organic-semiconductor material and the n-type organic-semiconductor material expresses high photoelectric conversion efficiency. In particular, a photoelectric conversion layer in which a p-type organic semiconductor material and an n-type organic semiconductor material are mixed is preferable because the junction interface is increased and the photoelectric conversion efficiency is improved.

  The p-type organic semiconductor material (compound) is a donor-type organic semiconductor material (compound), which is mainly represented by a hole-transporting organic compound and refers to an organic compound having a property of easily donating electrons. More specifically, an organic compound having a smaller ionization potential when two organic materials are used in contact with each other. Therefore, any organic compound can be used as the donor organic compound as long as it is an electron-donating organic compound. For example, triarylamine compound, benzidine compound, pyrazoline compound, styrylamine compound, hydrazone compound, triphenylmethane compound, carbazole compound, polysilane compound, thiophene compound, phthalocyanine compound, cyanine compound, merocyanine compound, oxonol compound, polyamine compound, indole Compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, condensed aromatic carbocyclic compounds (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives), nitrogen-containing heterocyclic compounds The metal complex etc. which it has as can be used. However, the present invention is not limited to this, and any organic compound having an ionization potential smaller than that of the organic compound used as the n-type (acceptor) compound as described above may be used as the donor organic semiconductor.

  The n-type organic semiconductor material (compound) is an acceptor organic semiconductor material, and is mainly represented by an electron-transporting organic compound and refers to an organic compound having a property of easily accepting electrons. More specifically, an n-type organic semiconductor refers to an organic compound having a larger electron affinity when two organic compounds are used in contact with each other. Therefore, any organic compound can be used as the acceptor organic compound as long as it is an electron-accepting organic compound. For example, condensed aromatic carbocyclic compounds (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives), 5- to 7-membered heterocyclic compounds containing nitrogen atoms, oxygen atoms, and sulfur atoms (E.g., pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, pyrazole, imidazole, thiazole, oxazole, indazole, benzimidazole, benzotriazole , Benzoxazole, benzothiazole, carbazole, purine, triazolopyridazine, triazolopyrimidine, tetrazaindene, oxy Diazole, imidazopyridine, pyrrolidine, pyrrolopyridine, thiadiazolopyridine, dibenzazepine, tribenzazepine, etc.), polyarylene compounds, fluorene compounds, cyclopentadiene compounds, silyl compounds, nitrogen-containing heterocyclic compounds as ligands Etc. Not limited to this, as described above, any organic compound having an electron affinity higher than that of the organic compound used as the p-type (donor property) compound may be used as the acceptor organic semiconductor.

  Any organic dye may be used as the p-type organic semiconductor material or the n-type organic semiconductor material, but preferably a cyanine dye, a styryl dye, a hemicyanine dye, and a merocyanine dye (including zero methine merocyanine (simple merocyanine)). 3-nuclear merocyanine dye, 4-nuclear merocyanine dye, rhodacyanine dye, complex cyanine dye, complex merocyanine dye, allopolar dye, oxonol dye, hemioxonol dye, squalium dye, croconium dye, azamethine dye, coumarin dye, arylidene dye, anthraquinone dye , Triphenylmethane dye, azo dye, azomethine dye, spiro compound, metallocene dye, fluorenone dye, fulgide dye, perylene dye, perinone dye, phenazine dye, pheno Azine dye, quinone dye, diphenylmethane dye, polyene dye, acridine dye, acridinone dye, diphenylamine dye, quinacridone dye, quinophthalone dye, phenoxazine dye, phthaloperylene dye, diketopyrrolopyrrole dye, dioxane dye, porphyrin dye, chlorophyll dye, phthalocyanine And dyes, metal complex dyes, and condensed aromatic carbocyclic dyes (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives).

As the n-type organic semiconductor material, it is particularly preferable to use fullerene or a fullerene derivative having excellent electron transport properties. The fullerene, fullerene _{C 60,} fullerene _{C 70,} fullerene _{C 76,} fullerene _{C 78,} fullerene _{C 80,} fullerene _{C 82,} fullerene _{C 84,} fullerene _{C 90,} fullerene _{C 96,} fullerene _{C 240,} fullerene _{C 540,} mixed Fullerene and fullerene nanotube are represented, and a fullerene derivative represents a compound having a substituent added thereto.

  The substituent for the fullerene derivative is preferably an alkyl group, an aryl group, or a heterocyclic group. The alkyl group is more preferably an alkyl group having 1 to 12 carbon atoms, and the aryl group and the heterocyclic group are preferably benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, fluorene ring, triphenylene ring, naphthacene ring. , Biphenyl ring, pyrrole ring, furan ring, thiophene ring, imidazole ring, oxazole ring, thiazole ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, indolizine ring, indole ring, benzofuran ring, benzothiophene ring, isobenzofuran Ring, benzimidazole ring, imidazopyridine ring, quinolidine ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinoxazoline ring, isoquinoline ring, carbazole ring, phenanthridine ring, acridine ring, phenanthroli Ring, thianthrene ring, chromene ring, xanthene ring, phenoxathiin ring, phenothiazine ring, or phenazine ring, more preferably a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, pyridine ring, imidazole ring, oxazole ring, Or a thiazole ring, particularly preferably a benzene ring, a naphthalene ring, or a pyridine ring. These may further have a substituent, and the substituents may be bonded as much as possible to form a ring. In addition, you may have a some substituent and they may be the same or different. A plurality of substituents may be combined as much as possible to form a ring.

  When the photoelectric conversion layer contains fullerene or a fullerene derivative, electrons generated by photoelectric conversion can be quickly transported to the pixel electrode 34 or the counter electrode 38 via the fullerene molecule or fullerene derivative molecule. When fullerene molecules or fullerene derivative molecules are connected to form an electron path, the electron transport property is improved, and high-speed response of the photoelectric conversion element can be realized. For this purpose, the fullerene or fullerene derivative is preferably contained in the photoelectric conversion layer by 40% (volume ratio) or more. If there are too many fullerenes or fullerene derivatives, the p-type organic semiconductor will decrease, the junction interface will become smaller, and the exciton dissociation efficiency will decrease.

  When the triarylamine compound described in Japanese Patent No. 4213832 is used as a p-type organic semiconductor material mixed with fullerene or a fullerene derivative in the photoelectric conversion layer 52, a high SN ratio of the photoelectric conversion element can be expressed. Is particularly preferred. If the ratio of fullerene or fullerene derivative in the photoelectric conversion layer is too large, the amount of triarylamine compounds decreases and the amount of incident light absorbed decreases. As a result, the photoelectric conversion efficiency is reduced. Therefore, the fullerene or fullerene derivative contained in the photoelectric conversion layer preferably has a composition of 85% (volume ratio) or less.

  An electron donating organic material can be used for the electron blocking layer 50. Specifically, for low molecular weight materials, N, N′-bis (3-methylphenyl)-(1,1′-biphenyl) -4,4′-diamine (TPD) and 4,4′-bis [N Aromatic diamine compounds such as-(naphthyl) -N-phenyl-amino] biphenyl (α-NPD), oxazole, oxadiazole, triazole, imidazole, imidazolone, stilbene derivative, pyrazoline derivative, tetrahydroimidazole, polyarylalkane, butadiene 4,4 ′, 4 ″ -tris (N- (3-methylphenyl) N-phenylamino) triphenylamine (m-MTDATA), porphine, tetraphenylporphine copper, phthalocyanine, copper phthalocyanine, titanium phthalocyanine oxide, etc. Porphyrin compounds, triazole derivatives, Sadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, annealed amine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, silazane derivatives, carbazole derivatives, bifluorenes Derivatives and the like can be used, and as the polymer material, polymers such as phenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, and diacetylene, and derivatives thereof can be used. It is possible to use any compound that has sufficient hole transport properties, even if it is not a functional compound.

  As the electron blocking layer 50, an inorganic material can also be used. In general, since an inorganic material has a dielectric constant larger than that of an organic material, when it is used for the electron blocking layer 50, a large voltage is applied to the photoelectric conversion layer, and the photoelectric conversion efficiency can be increased. Materials that can be used as the electron blocking layer 50 include calcium oxide, chromium oxide, chromium oxide copper, manganese oxide, cobalt oxide, nickel oxide, copper oxide, gallium copper oxide, strontium copper oxide, niobium oxide, molybdenum oxide, indium copper oxide, Examples include indium silver oxide and iridium oxide.

In the electron blocking layer composed of a plurality of layers, the layer adjacent to the photoelectric conversion layer 52 among the plurality of layers is preferably a layer made of the same material as the p-type organic semiconductor contained in the photoelectric conversion layer 52. Thus, by using the same p-type organic semiconductor for the electron blocking layer 50, it is possible to suppress the formation of intermediate levels at the interface between the photoelectric conversion layer 52 and the adjacent layer, and to further suppress the dark current. Can do.
When the electron blocking layer 50 is a single layer, the layer can be a layer made of an inorganic material, and when it is a plurality of layers, one or more layers can be a layer made of an inorganic material.

Next, a manufacturing method of the image sensor 20 will be described.
FIGS. 4A and 4B are schematic cross-sectional views illustrating the manufacturing method of the image sensor according to the embodiment of the present invention in the order of steps, and FIGS. 5A and 5B are diagrams of the embodiment of the present invention. It is typical sectional drawing which shows the manufacturing method of an image pick-up element in order of a process, and shows the post process of FIG.4 (b).
In the method of manufacturing the image sensor 20 according to the embodiment of the present invention, first, as shown in FIG. 4A, a first circuit is formed on a substrate 30 on which a readout circuit 60 and a counter electrode voltage supply unit 62 are formed. The insulating layer 32 provided with the connecting portion 64, the second connecting portion 66, and the wiring layer 68 is formed, and the pixel electrode 34 connected to each first connecting portion 64 is further formed on the surface 32a of the insulating layer 32. A formed circuit board 35 (CMOS substrate) is prepared. In this case, as described above, the first connection unit 64 and the readout circuit 60 are connected, and the second connection unit 66 and the counter electrode voltage supply unit 62 are connected. The pixel electrode 34 is made of, for example, TiN.

  Next, the electron blocking layer 50 is transferred to a film forming chamber (not shown) by a predetermined transfer path, and as shown in FIG. 4B, all the pixel electrodes except for the second connection portion 66. The electron blocking material is formed into a film under a predetermined vacuum using, for example, an evaporation method so as to cover 34, thereby forming the electron blocking layer 50. As the electron blocking material, for example, a carbazole derivative, more preferably a bifluorene derivative is used.

  Next, the photoelectric conversion layer 52 is transported to a film forming chamber (not shown) by a predetermined transport path, and the photoelectric conversion layer 52 is deposited on the surface 50a of the electron blocking layer 50 by a predetermined vacuum using, for example, a vapor deposition method. Form below. As the photoelectric conversion material, for example, a p-type organic semiconductor material and fullerene or a fullerene derivative are used. Thereby, the photoelectric conversion layer 52 is formed and the organic layer 36 is formed.

  Next, after transporting to a film forming chamber (not shown) of the counter electrode 38 through a predetermined transport path, the organic layer 36 (the photoelectric conversion layer 52 and the electron blocking layer 50) is covered, and the second connection portion 66 is covered. The counter electrode 38 is formed in a predetermined vacuum by using, for example, a sputtering method with the pattern formed in (1).

Next, the protective film 40 is transferred to a film forming chamber (not shown) through a predetermined transfer path, and as shown in FIG. 5A, the counter electrode 38 is covered so as to cover the surface 32a of the insulating layer 32. As the protective film 40, for example, a first silicon oxynitride layer 41a having a thickness of 100 nm and a second silicon oxynitride layer 41b having a thickness of 100 nm are stacked by an RF plasma CVD method.
In this case, as the protective film 40, a silicon oxynitride layer having the above composition and density is formed using a plasma CVD method at a predetermined substrate temperature (film formation temperature), for example, 245 ° C. or lower. As for the composition and density of the silicon oxynitride layer, the silicon oxynitride layer is formed in advance by changing the flow rate of the reaction gas, etc., and the film formation conditions (film formation temperature, pressure during film formation, high frequency power during film formation, By determining the gas type (SiH ₄ , NH ₃ , N ₂ O), gas mixing ratio, etc.), a silicon oxynitride layer within the above composition range can be formed.

In the formation of the protective film 40, like the above-described protective film 16, after forming the first silicon oxynitride layer 41a, at least one of the pressure during deposition and the high-frequency power is changed among the film formation conditions. A second silicon oxynitride layer 41b is formed. Thereby, the density of the second silicon oxynitride layer 41b can be made 0.05 (g / cm ³ ) or more higher than the density of the first silicon oxynitride layer 41a, and the film stress can be changed. Moreover, the refractive index difference can be made within 0.1, preferably within 0.05.
In addition, among the deposition conditions, the first silicon oxynitride layer 41a and the second silicon oxynitride layer 41b are continuously changed without stopping the deposition gas by changing at least one of the pressure during deposition and the high-frequency power. And can be formed.

  Next, as illustrated in FIG. 5B, the color filter 42, the partition wall 44, and the light shielding layer 46 are formed on the surface 40 a of the protective film 40 using, for example, a photolithography method. As the color filter 42, the partition wall 44, and the light shielding layer 46, known ones used for organic solid-state imaging devices are used. The formation process of the color filter 42, the partition wall 44, and the light shielding layer 46 may be under a predetermined vacuum or non-vacuum.

Next, an overcoat layer 48 is formed using, for example, a coating method so as to cover the color filter 42, the partition wall 44, and the surface 47 of the light shielding layer 46. Thereby, the image sensor 20 shown in FIG. 3 can be formed. As the overcoat layer 48, a known layer used for an organic solid-state imaging device is used. The overcoat layer 48 may be formed in a predetermined vacuum or non-vacuum.
When the overcoat layer 48 is formed of a multi-layered silicon oxynitride layer (SiOxNy layer), it can be formed by the same method as the protective film 40.

Hereinafter, other specific examples of the substrate with an organic functional layer will be described.
The board | substrate with an organic functional layer of this invention can also be called an organic solar cell and an organic EL element, for example.
FIG. 6A is a schematic cross-sectional view showing the organic solar cell according to the embodiment of the present invention, and FIG. 6B is a schematic cross-sectional view showing the organic EL element of the embodiment of the present invention.
The organic solar cell 70 shown in FIG. 6A has an organic photoelectric conversion layer 76. This organic photoelectric conversion layer 76 corresponds to the organic functional layer of the present invention. The organic solar cell 70 is formed by laminating a lower electrode 74, an organic photoelectric conversion layer 76, a transparent electrode (upper electrode) 78, and a protective film 80 in this order on a substrate 72. Incident light L is incident from the transparent electrode 78 side. The organic photoelectric conversion layer 76 has a heat resistance of 245 ° C. or less, for example.

The protective film 80 has the same two-layer structure as the protective film 16 described above, and has the same composition and density as the protective film 16. Even in this case, in the protective film 80, the second silicon oxynitride layer 81b far from the organic photoelectric conversion layer 76 has a thickness of 50 nm or more. The protective film 80 is formed by the same manufacturing method as the protective film 16. For this reason, the detailed description is abbreviate | omitted. The board | substrate 72 is corresponded to the base material 12 (refer Fig.1 (a)) of this invention.
The protective film 80 is composed of a first silicon oxynitride layer 81a and a second silicon oxynitride layer 81b. The protective film 80 can be configured as shown in FIG. 1B and FIGS. 2A to 2C, like the protective film 16.

The lower electrode 74, the organic photoelectric conversion layer 76, and the transparent electrode 78 are configured by general materials used for known organic solar cells. For this reason, the detailed description is abbreviate | omitted.
The current generated in the organic photoelectric conversion layer 76 by the irradiation of the incident light L is taken out by the lower electrode 74 and the transparent electrode 78.
Also in the organic solar cell 70 having such a configuration, the organic photoelectric conversion layer 76 can be protected over a long period of time in a high temperature and high humidity environment by providing the same protective film 80 as the protective film 16 described above. Thereby, durability of the organic solar cell 70 can be improved. Moreover, the protective film 80 is transparent as described above, and does not prevent the incident light L from entering the organic photoelectric conversion layer 76.

An organic EL element 70a shown in FIG. 6B is a light emitting element using the organic EL layer 86, and is called a top emission method. In addition, in the organic EL element 70a, the same code | symbol is attached | subjected to a structure similarly to the organic solar cell 70 shown to Fig.6 (a), and the detailed description is abbreviate | omitted.
The organic EL layer 86 corresponds to the organic functional layer of the present invention. In the organic EL element 70a, a TFT 82, a cathode 84, an organic EL layer 86, a transparent electrode (upper electrode) 78, and a protective film 80 are laminated on a substrate 72 in this order. A power source 88 is connected to the TFT 82, the cathode 84 and the transparent electrode 78. The protective film 80 is the same as the organic solar cell 70 shown in FIG. 6A and has a two-layer structure. Even in this case, in the protective film 80, the second silicon oxynitride layer 81b far from the organic EL layer 86 has a thickness of 50 nm or more. Further, the protective film 80 may be configured as shown in FIG. 1B and FIGS. 2A to 2C, like the protective film 16.

The organic EL layer 86 is a portion that emits light, and is a layer in which a hole injection layer, a hole transport layer, a light emitting layer, an electron injection / transport layer, and the like are sequentially stacked. The organic EL layer 86 has a heat resistance of 245 ° C. or lower, for example.
The cathode 84 and the transparent electrode 78 are for applying a voltage necessary for causing the organic EL layer 86 to emit light, and the TFT 82 is for controlling the light emission of the organic EL element 70a.
The power supply 88 generates a voltage necessary for causing the organic EL layer 86 to emit light, and drives the TFT 82.
The TFT 82, the cathode 84, the organic EL layer 86, and the transparent electrode 78 are appropriately configured with general materials used for known organic EL elements. For this reason, the detailed description is abbreviate | omitted.

  Also in the organic EL element 70a having such a configuration, by providing the same protective film 80 as the above-described protective film 16, the organic EL layer 86 can be protected over a long period of time in a high temperature and high humidity environment. Thereby, durability of the organic EL element 70a can be improved. Moreover, the protective film 80 is transparent as described above, and does not affect the light emitted from the organic EL layer 86.

  The protective film of the present invention is not limited to any of the above-described examples. The protective film is protected for a long time in a high temperature and high humidity environment, and the incident light to the organic functional layer and the light from the organic functional layer are protected. It can be suitably used for those requiring transparency that does not interfere with emission. For example, even if the heat resistance of the organic functional layer is 245 ° C. or lower, the organic functional layer is protected for a long time in a high-temperature and high-humidity environment as described above, and light is incident on the organic functional layer and light from the organic functional layer. Can be used as appropriate for those requiring transparency that does not hinder the emission of light.

Hereinafter, the film stress of the protective film 16 and the protective film 40 and the measurement method thereof will be described. Since the protective film 16 and the protective film 40 have the same configuration, the protective film 16 will be described as an example. Note that the overcoat layer 48 can have the same configuration as the protective film 40. For this reason, the description of the following film stress and its measuring method includes the overcoat layer 48.
As shown in FIGS. 7A and 7B, the stress acting on the thin film 102 is described as the stress acting on the protective film 16, taking as an example the substrate 100 on which the thin film 102 corresponding to the protective film 16 is formed. To do. The protective film 16 is a multilayer structure, and if the stress is measured using the multilayer structure as one film, the film stress of the protective film 16 can be obtained. The film stress of the protective film 16 can also be measured by measuring the stress of each silicon oxynitride layer of the protective film 16 in a single layer state and obtaining the average of the respective stresses.

FIG. 7A shows the direction of the compressive stress σ _c acting on the thin film 102 by an arrow when the substrate 100 on which the thin film 102 is formed is expanded. 7A, when the substrate 100 is warped so that the side on which the thin film 102 is formed protrudes, the thin film 102 formed on the substrate 100 expands, and the thin film 102 in close contact with the substrate 100 is obtained. The force that tries to compress it works. This force is compressive stress sigma _c.

In FIG. 7B, the direction of the tensile stress σ _t acting on the thin film 102 when the substrate 100 on which the thin film 102 is formed is contracted is indicated by an arrow. As shown in FIG. 7B, when the substrate 100 is warped so that the side on which the thin film 102 is formed is depressed, the thin film 102 formed on the substrate 100 contracts, and the thin film 102 in close contact with the substrate 100. The force which tries to extend to works. This force is a tensile stress σ _t.

Here, the compressive stress σ _c and the tensile stress σ _t of the thin film 102 affect the amount of warpage of the substrate 100. Next, the stress can be measured using an optical lever method based on the warpage amount of the substrate 100.
FIG. 8 is a schematic diagram showing a measuring apparatus for measuring the amount of warpage of a substrate on which a thin film is formed. A measuring apparatus 200 shown in FIG. 8 includes a laser irradiation unit 202 that irradiates laser light, a splitter 204 that reflects part of light emitted from the laser irradiation unit 202 and transmits other light, and a splitter. And a mirror 206 for reflecting the light transmitted through 204. On one surface of the substrate 100, a thin film 102 which is an object to be measured is formed. The light reflected by the splitter 204 is irradiated onto the thin film 102 of the substrate 100, and the reflection angle of the light reflected by the surface of the thin film 102 at that time is detected by the first detection unit 208. The light reflected by the mirror 206 is applied to the thin film 102 of the substrate 100, and the reflection angle of the light reflected by the surface of the thin film 102 at that time is detected by the second detection unit 210.
FIG. 8 shows an example in which the compressive stress acting on the thin film 102 is measured by bending the substrate 100 so that the surface on which the thin film 102 is formed protrudes. Here, the thickness of the substrate 100 is h, and the thickness of the thin film 102 is t.

Next, a procedure for measuring the stress of the thin film by the measuring apparatus 200 will be described.
As an apparatus used for the measurement, for example, a thin film stress measuring apparatus FLX-2320-S manufactured by Toago Technology Co., Ltd. can be used. The measurement conditions when this apparatus is used are shown below.

(Laser light (laser irradiation unit 202))
Laser used: KLA-Tencor-2320-S
Laser power: 4mW
Laser wavelength: 670 nm
Scanning speed: 30mm / s

(substrate)
Substrate material: Silicon (Si)
Direction: <100>
Type: P type (Dopant: Boron)
Thickness: 250 ± 25 μm or 280 ± 25 μm

(Measurement procedure)
The amount of curvature of the substrate 100 on which the thin film 102 is formed is measured in advance, and the curvature radius R1 of the substrate 100 is obtained. Subsequently, the thin film 102 is formed on one surface of the substrate 100, the amount of warpage of the substrate 100 is measured, and the curvature radius R2 is obtained. Here, the amount of warpage is calculated from the reflection angle of the laser light reflected from the substrate 100 by scanning the surface of the substrate 100 on which the thin film 102 is formed with a laser as shown in FIG. The radius of curvature R = R1 · R2 / (R1-R2) is calculated based on the amount of warpage.

  Thereafter, the stress of the thin film 102 is calculated by the following calculation formula. The unit of stress of the thin film 102 is represented by Pa. A negative value is indicated for compressive stress, and a positive value is indicated for tensile stress. Note that a method for measuring the stress of the thin film 102 is not particularly limited, and a known method can be used.

(Stress stress calculation formula)
^{σ = E × h 2/6} (1-ν) Rt
Where E / (1-ν): biaxial elastic modulus (Pa) of the underlying substrate, ν: Poisson's ratio h: thickness of the underlying substrate (m),
t: film thickness (m) of the thin film,
R: radius of curvature of base substrate (m),
σ: The average stress (Pa) of the thin film.

  The present invention is basically configured as described above. As mentioned above, although the board | substrate with an organic functional layer of this invention and its manufacturing method were demonstrated in detail, this invention is not limited to the said embodiment, In the range which does not deviate from the main point of this invention, various improvement or a change is carried out. Of course it is also good.

Hereinafter, the effect of the protective film of the present invention will be specifically described.
In this example, samples of Examples 1 to 4 and Comparative Examples 1 to 5 were prepared, and the effect of the protective film of the present invention was confirmed.

In this embodiment, as a sample, a pixel electrode is formed on a part of the surface of the base material on the base material, and an organic functional layer is formed on the base material as a photoelectric conversion layer so as to cover the pixel electrode. A photoelectric conversion element main body having a simplified structure in which a counter electrode is formed on the organic functional layer and a protective film covering the counter electrode is formed was used.
In addition, the thing of the 2 layer structure of the silicon oxynitride layer represented by SiOxNy was used for the protective film.
The samples of Examples 1 to 4 and Comparative Examples 1 to 5 used element units described later having the same configuration except for the configuration of the protective film.

Hereinafter, the element unit will be described.
For each sample, an element unit formed as follows was prepared.
A non-alkali glass substrate having a thickness of 0.7 mm was prepared as a substrate, and an indium tin oxide (ITO) film having a thickness of 100 nm was formed as a pixel electrode on the substrate by a sputtering method.
Next, a material represented by the following chemical formula 1 was deposited as an electron blocking layer on the substrate so as to have a thickness of 100 nm at a deposition rate of 10 to 20 nm / s as an electron blocking layer so as to cover the image electrode. . Next, as an organic layer (photoelectric conversion layer), a material represented by the following chemical formula 2 (fullerene C ₆₀ ) and a material represented by the following chemical formula 3 are deposited at a deposition rate of 16 to 18 nm / s and 25 to 28 nm / s, respectively. Co-evaporated so that the volume ratio of the material shown in 2 and the material shown in chemical formula 3 below was 1: 3, and formed to a thickness of 400 nm.

Next, as a counter electrode, an indium tin oxide (ITO) film having a thickness of 10 nm was formed on the organic layer by sputtering to cover the organic layer.
Next, an aluminum oxide film (AlOx film) having a thickness of 30 nm was formed on the counter electrode by atomic layer deposition chemical vapor deposition (AL-CVD).

The sample of Example 1 was produced as follows.
A silicon oxynitride layer (SiOxNy layer) having a thickness of 200 nm is formed as a protective film on the aluminum oxide film and the base material by plasma CVD so as to cover the counter electrode of the element unit thus prepared. Formed. Thus, the sample of Example 1 was produced.

The composition and density of the protective film of each sample of Examples 1 to 4 and Comparative Examples 1 to 5 are as shown in Table 1 below. It should be noted that the protective film is formed in advance so as to have a predetermined composition and density (film formation temperature (substrate temperature), pressure during film formation, high-frequency power during film formation, gas type (SiH ₄ , NH ₃ , N ₂ O) and gas mixing ratio, etc.) were determined, and a film was formed under the production conditions. Examples 1 to 4 and Comparative Example 1 were prepared by fixing the gas flow rate and the high-frequency frequency during film formation, and changing at least only the high-frequency power among the pressure and high-frequency power during film formation. A protective film for each sample of ~ 5 was made separately. The film forming temperature was 154 ° C. In Table 1 below, the pressure during film formation is simply referred to as gas pressure.

In this example, the film density and film stress were measured for the protective films of the samples of Examples 1 to 4 and Comparative Examples 1 to 5, and the refractive index at a wavelength of 550 nm was measured using an ellipsometer. The results are shown in Table 1 below.
Further, the samples of Examples 1 to 4 and Comparative Examples 1 to 5 were left in an environment having a temperature of 85 ° C. and a relative humidity of 85%, and the dark current after being left in the above environment was not left in the above environment. The time required to reach twice the value was measured. This measurement time was defined as the life. The results are shown in Table 1 below.
In order to investigate the loss due to the reflected light of each sample of Examples 1 to 4 and Comparative Examples 1 to 5, the reflectance of the protective film was measured. In this embodiment, the reflectance is an average value of the reflectances having a wavelength of 500 to 600 nm. A spectroscopic reflection measuring instrument (U-4000 manufactured by Hitachi, Ltd.) was used for the reflectance measurement.
In the evaluation of the reflectance, the average value of the reflectance at a wavelength of 500 to 600 nm is 5% or less as “A”, the above average value is more than 5% and 6% or less as “B”, The above-mentioned average value exceeding 6% was designated as “C”. The results are shown in Table 1 below.

Furthermore, in this example, after immersing each sample of Examples 1 to 4 and Comparative Examples 1 to 5 in acetone for 30 seconds, the state of the protective film was observed using an optical microscope (5 times magnification), The presence or absence of peeling of the protective film was examined. The results are shown in Table 1 below.
In the evaluation of the peeling of the protective film, the case where there was no change in the protective film before and after the immersion was set to “None”, and even if a part of the protective film was peeled off by the immersion, or a part of the protective film was wrinkled. The result is “Yes”.

The film density was measured as follows.
Rigaku ATX-G was used as the measuring device for the film density. A Cu target was used as the X-ray source, and X-rays were generated at 50 keV-300 mA. The S1 slit is 0.5 mm wide and 5 mm high. The incident side optical element is a Ge (220) crystal. The S2 slit has a width of 0.05 mm and a height of 10 mm. The receiving slit has a width of 0.1 mm and a height of 10 mm. No light receiving side optical element. The Gurard slit is 0.2 mm wide and 20 mm high. The scan axis is 2θ / ω, the scan range is 0 to 2 °, the sampling range is 0.001 °, and the scan speed is 0.1 ° / min. The film density was calculated by fitting simulation of the measured profile.
The film stress was measured using the method shown in FIG.

The composition of the film was measured as follows.
As a film composition measurement instrument, PHI Quantara SXM and a monochromatic Al-Kα ray of 15 kV-25 W as an X-ray source were used. The depth direction analysis was performed by Ar ⁺ etching / XPS. Regarding Ar ⁺ etching, the acceleration voltage of Ar ⁺ was 3 kV, and the etching area was 2 × 2 mm ² . Regarding XPS, the X-ray irradiation range and the analysis range were 300 × 300 μm ² , the pass energy was 112 eV, and the step was 0.2 eV. There was charging correction (both electron gun and low-speed ion gun), and each intensity of C1s, O1s, N1s, and Si2p was corrected with a sensitivity coefficient, and converted to an atomic ratio.
Regarding the dark current, an electric field of 2 × 10 ⁵ V / cm was applied to the counter electrode side in an environment of 60 ° C. with the photoelectric conversion element body shielded from light, and in this state, a source meter (Keithley 6430) The value of the current measured using was used as the dark current.

As shown in Table 1 above, in Examples 1 to 4, the entire film stress of the protective film was −5 MPa to −220 MPa (compressive stress), and was a region suitable as the film stress. In addition, even in an environment of a temperature of 85 ° C. and a relative humidity of 85%, the time until the dark current doubled is at least 1000 hours of Example 1, and the durability could be improved. Moreover, the reflectance did not exceed 6%, and good results were obtained with little loss due to reflected light.
Further, in Examples 1 to 4, the protective film was not peeled off. This is because in the present invention, since the density difference of the protective film is in an appropriate range, the film stress of the entire protective film is in an appropriate range, and the film does not peel off. In Examples 1 and 2, the difference in refractive index is within a preferable range of 0.05 or less, the reflectance is small, and the loss due to reflected light is small.
In Example 1, the density of the upper layer and the lower layer could be changed by changing the pressure during deposition and the high frequency power. In Example 2, the density of the upper layer and the lower layer could be changed by changing only the high frequency power.

On the other hand, in Comparative Example 1, the density of the upper and lower layers of the protective film is the same, and the composition is also the same. The overall film stress of the protective film is +60 MPa and tensile stress acts, and the temperature 85 ° C. and relative humidity 85% resistance is also low at 10 hours.
In Comparative Example 2, the density of the upper layer and the lower layer of the protective film is the same, and the composition is also the same. Although the overall film stress of the protective film is −160 MPa and compressive stress is applied, the temperature 85 ° C. and relative humidity 85% resistance is as low as 850 hours.
In Comparative Example 3, the upper layer and the lower layer of the protective film had the same composition, and the temperature 85 ° C. and relative humidity 85% resistance were 1000 hours. In Comparative Example 3, the entire film stress of the protective film was −280 MPa and compressive stress was applied, and the protective film was peeled off.

In Comparative Example 4, the entire film stress of the protective film is −140 MPa and compressive stress is applied, but the refractive index difference exceeds the range of the present invention. In Comparative Example 4, the gas pressure during film formation of the upper layer is as low as 70 Pa, and the temperature 85 ° C. and relative humidity 85% resistance are as low as 500 hours. Moreover, the reflectivity is large and the loss due to the reflected light is also large.
In Comparative Example 5, the compressive stress acts as the whole film stress of the protective film is -140 MPa, but the refractive index difference exceeds the range of the present invention. In Comparative Example 5, the gas pressure during film formation of the upper layer is as low as 50 Pa, and the temperature 85 ° C. and relative humidity 85% resistance is as low as 500 hours. Moreover, the reflectivity is large and the loss due to the reflected light is also large. Furthermore, the entire film stress of the protective film was −260 MPa and compressive stress was applied, and the protective film was peeled off.

DESCRIPTION OF SYMBOLS 10 Substrate with organic layer 12 Base material 14 Organic functional layer 16, 40, 80 Protective film 16a, 41a, 81a First silicon oxynitride layer 16b, 41b, 81b Second silicon oxynitride layer 20 Imaging element 30 Substrate 32 Insulation Layer 34 Pixel electrode (lower electrode)
36 organic layer 48 overcoat layer 50 electron blocking layer 52 photoelectric conversion layer 70 organic solar cell 70a organic EL element

Claims (7)

A substrate;
An organic functional layer disposed on the substrate;
A protective film disposed on the organic functional layer,
The protective film has a plurality of silicon oxynitride layers, and each silicon oxynitride layer has a refractive index difference of 0.1 or less in absolute value,
In the protective film, among the plurality of silicon oxynitride layers, the silicon oxynitride layer far from the organic functional layer has a thickness of 50 nm or more and the density is formed at a position closest to the organic functional layer A substrate with an organic functional layer, which is 0.05 (g / cm ³ ) or more larger than the density of the formed silicon oxynitride layer.   The said protective film is a board | substrate with an organic functional layer of Claim 1 which has another layer in at least one among the outer sides between each silicon oxynitride layer.   The substrate with an organic functional layer according to claim 1, wherein the organic functional layer has a heat resistance of 245 ° C. or lower. The organic functional layer is an organic photoelectric conversion layer that generates charges when irradiated with light,
The organic photoelectric conversion layer is provided with a lower electrode on the substrate side and a transparent upper electrode on the opposite side of the substrate,
The substrate with an organic functional layer according to claim 1, wherein the protective film is disposed on the upper electrode. The organic functional layer is a color filter layer containing an organic substance,
The substrate with an organic functional layer according to claim 1, wherein the protective film is disposed on the color filter layer. A protective film forming step of forming a plurality of silicon oxynitride layers as a protective film on the organic functional layer disposed on the substrate by using a plasma CVD method;
In the protective film forming step, the silicon oxynitride layer far from the organic functional layer is changed to the organic functional layer by changing at least one of the pressure during deposition and the high frequency power among the film forming conditions in the plasma CVD method. A method for producing a substrate with an organic functional layer, characterized in that it is formed 0.05 (g / cm ³ ) or more larger than the density of a silicon oxynitride layer formed at a position closest to the substrate.   The method for producing a substrate with an organic functional layer according to claim 6, wherein the organic functional layer has a heat resistance of 245 ° C. or lower.