JP4984528B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus that captures incident light by a light receiving sensor and converts it into an electrical signal, and more particularly relates to an imaging apparatus that includes a filter that selects a specific wavelength of light traveling toward the light receiving sensor.

  Among image sensors that are imaging devices, those that have a function of identifying colors by using color filters are currently mainstream. Usually, the three primary colors, red, green, and blue, are used to identify the colors, and by providing a semiconductor layer that detects light under each filter, the three primary colors that have passed through the filter are separated separately. To detect.

  On the other hand, in recent years, a sensor for identifying a color by using the fact that the absorption coefficient of a semiconductor differs depending on the wavelength of light has been considered. This means that the layers for detecting blue, green, and red light in the depth direction from the surface of the Si (silicon) semiconductor are blue using the fact that the absorption coefficient of the three primary colors decreases in the order of blue, green, and red. , Green, and red (for example, refer to Patent Document 1).

US Pat. No. 5,965,875

  However, when the color filter method is used as the imaging device, the efficiency is poor because a large amount of light is cut. In particular, when each color is identified using filters of the three primary colors of red, green, and blue, the amount of light falls to 1/3 or less by itself. Further, since sensors are required for each color, three sensors are required for one pixel, so the resolution is lowered. In addition, the cost is increased due to the need for color filters. In addition, since dyes, pigments, and polymers are usually used for color filters, they are vulnerable to high temperature conditions and changes over time, and there is a problem with light resistance.

  On the other hand, in the imaging device using the difference in absorption coefficient depending on the wavelength, the amount of light that can be detected theoretically does not decrease, but in the layer that detects blue light, when red light or green light passes, it absorbs to some extent, Light is detected as blue light (color mixture). For this reason, even if there is no blue signal, a green or red signal is input, so that a blue signal is also input.

  In order to avoid this, correction is performed by signal processing by calculation for all three primary colors. However, for example, if one of the ternary colors is saturated, the original value of the saturated light is not known, resulting in a calculation error, and as a result, the signal is processed differently from the original color. . Further, since a circuit necessary for the calculation is separately required, the cost is increased.

The present invention has been made to solve such problems. That is, according to the present invention, two or more light receiving sensors provided to be stacked at different depths of the substrate and the wavelength of light incident on the two or more light receiving sensors are complementary colors for red, green, and blue. And an interference filter made of a dielectric multilayer film selected from the above . This filter is an imaging device that satisfies d = λ / (4 × n) where λ is the center wavelength of light to be selected, d is the thickness of each layer of the multilayer film, and n is the refractive index of each layer. .

In particular, in the present invention, the multilayer film of the filter is composed of a combination of a silicon nitride film (Si _x N _y film: for example, Si ₃ N ₄ film) and silicon oxide (SiO _x film: for example, SiO ₂ film). Something is used. By using such a multilayer film, especially a dielectric multilayer film as a filter, the filter has better light transmission than a color filter made of dyes or pigments, and is resistant to light resistance, durability, and aging. Can be realized.

In the imaging device provided with a primary color filter that selects a wavelength of the primary colors as the aforementioned filter, the primary color filters are constituted by a plurality of sets of multi-layer film having two or more periods.

  In the present invention, since the primary color filter is composed of a plurality of sets of multilayer films having two or more periods, the light transmittance is superior to that in the case of using a color filter made of a dye or pigment, and light resistance is improved. It is possible to realize a filter that is resistant to durability, durability and changes over time.

In the present invention, two or more light receiving sensors provided at different depths of the substrate and the wavelength of light incident on the two or more light receiving sensors are selected from complementary colors for red, green, and blue And an interference filter made of a dielectric multilayer film.

  In the present invention, the wavelength of the incident light is selected by the interference filter made of the dielectric multilayer film, and the substrate is made up of two or more light receiving sensors provided at different depths of the substrate for the light of the selected wavelength. Light of a wavelength corresponding to each light receiving sensor is received by a wavelength selection function based on depth. Because this filter uses an interference filter made of a dielectric multilayer film, it is superior in light transmission compared to the case of using a color filter made of a dye or pigment, and has a light resistance, durability, and resistance to changes over time. Can be realized.

  Therefore, according to the present invention, it is possible to provide an imaging device that suppresses color mixing due to photoelectric conversion and has excellent color reproducibility. In addition, since no dye, pigment, or polymer material is used as a filter, it is possible to realize an imaging device that has good light resistance, durability even at high temperatures, and resistance to changes over time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram of a filter applied in the imaging apparatus according to the present embodiment. In the imaging apparatus according to the present embodiment, the filter 10 made of a dielectric multilayer film is used to select the wavelength of light incident on a sensor (imaging device: photodiode) that performs photoelectric conversion. The dielectric multilayer film of the filter 10 has a structure in which a plurality of layers having different refractive indexes are stacked as shown in this figure. When light is incident on such a structure, the reflectance is reduced by the interference of light in the multilayer film. Has some dependency on.

In particular, this and dielectric multilayer films periodic structures, certain conditions (e.g., conditions d = λ _0/4 × n of the thicknesses of the layers d) to have a, only the reflectance of a specific wavelength range of light It is possible to effectively increase (that is, the transmittance is small) and to reduce the reflectance of light in other wavelength regions (that is, the transmittance is large). Here, λ ₀ is the center wavelength of a certain wavelength region, and n is the refractive index of the layer.

  With the filter 10 composed of such a dielectric multilayer film, for example, only a specific wavelength region can be reflected as in the reflection spectrum shown in FIG. In the present embodiment, the dielectric multilayer film is formed on the upper side (light incident surface side) of the sensor, and part of visible light is reflected and the remaining light is transmitted, so that the transmitted light enters the sensor. . At this time, the transmittance with respect to the wavelength is a transmission spectrum as shown in FIG.

  FIG. 3 is a schematic cross-sectional view illustrating a cross-sectional structure of the imaging apparatus according to the present embodiment. The thickness of each layer of the filter 10 made of a dielectric multilayer film is within ± 10% of the calculated thickness, so that a color filter having a desired wavelength is obtained. Particularly desirable characteristics can be obtained within ± 5%.

  By forming such a filter 10 on the sensor 20, based on the spectrum as shown in FIG. 2, a part of incident light is reflected and a part of the incident light is transmitted and only light having a target wavelength is transmitted. It becomes possible to enter.

  Next, characteristics of the filter used in the imaging apparatus according to the present embodiment will be described. FIG. 4 is a schematic configuration diagram of a filter having a multilayer structure. 5 to 8 show the results of reflection spectra calculated by satisfying the conditions of the following formula and constituting the multilayer film structure filter shown in FIG. 4 and changing the refractive index difference. However, in this calculation, the refractive index of one of the two types of layers is fixed (n1 = 1.48), and the refractive index n2 of the other layer is changed.

d1 = λ _C / (4 × n1)
d2 = λ _C / (4 × n2)

Here, λ _C is the center wavelength of the light to be reflected, d 1 and n 1, d 2 and n 2 are the refractive index and thickness. 5 to 8 show cases where λ _C = 200 nm, 250 nm, 700 nm, and 900 nm, respectively.

Based on the above results, the wavelength λ _1/2 where the reflectance peak value is half as shown in FIG. 9 and the first bottom wavelength λ _Edge are obtained, and the horizontal axis indicates the refractive index difference Δn. The results plotted as wavelengths on the axes are shown in FIGS. Here, when λ _C = λ ₁ = 200 nm and 250 nm (see FIGS. 9A and 10), the wavelength is longer than the peak, and conversely, when λ _C = λ ₂ = 700 nm and 900 nm (FIG. 9B ) And FIG. 11) read the wavelength on the shorter wavelength side than the peak.

The formulas obtained by the least square method from the plot shown in FIG. 10 are summarized as follows.
λ ₁ = 200 nm
λ _Edge = 29.657 × Δn + 388.54
λ _1/2 = 42.678 × Δn + 246.86
λ ₁ = 250 nm
λ _Edge = 37.054 × Δn + 485.37
λ _1/2 = 53.088 × Δn + 308.73

Than this,
λ _Edge = (0.148 × Δn + 1.942) × λ ₁ (1)
λ _1/2 = (0.213 × Δn + 1.234) × λ ₁ (2)
Is obtained.

Further, the equations obtained by the least square method from the plot shown in FIG. 11 are summarized as follows.
λ ₂ = 700 nm
λ _Edge = −8.4997 × Δn ′ + 468.38
λ _1/2 = −28.452 × Δn ′ + 563.21
λ ₂ = 900 nm
λ _Edge = −9.8745 × Δn ′ + 600.13
λ _1/2 = −38.326 × Δn ′ + 728.34

from now on,
λ _Edge = (− 0.0115 × Δn ′ + 0.668) × λ ₂ (3)
λ _1/2 = (− 0.0415 × Δn ′ + 0.807) × λ ₂ (4)
Is obtained.

The above results are for the case where the multilayer structure shown in FIG. 4 has two periods (two layers correspond to one period). Next, the refractive index difference Δn = 2.62 is fixed and the period dependence is λ. _The results of investigation under the conditions of _C = 250 nm and 700 nm are shown in FIGS. 12 and 13, respectively.

Similarly, from these results, the wavelength λ _1/2 where the reflectance peak value is half the value and the first bottom wavelength λ _Edge are obtained, and the horizontal axis represents the period m, m ′ and the vertical axis represents the wavelength plotted. Are shown in FIGS.

The formulas obtained by the least square method from the results shown in FIG. 14 are summarized as follows.
λ ₁ = 250 nm
λ _Edge = 329.03 + 1534.9 × exp (−1.0374 × m)
λ _1/2 = 317.55 + 281.56 × exp (−0.946 × m)

From this, λ _Edge = (1.316 + 6.1396 × e ^{−1.0374 × m} ) × λ ₁
λ _1/2 = (1.2702 + 1.12624 × e ^{−0.946 × m} ) × λ ₁

These results are the results of fixing the refractive index difference Δn = 2.62. Here, when m = 2, the expressions obtained by normalizing the coefficient term on the left side to 1 are as follows.
1 / (1.316 + 6.1396 × e ^{−1.0374 × 2} ) × (1.316 + 6.1396 × e ^{−1.0374 × m} ) × λ ₁
1 / (1.2702 + 1.12624 × e ^{−0.946 × 2} ) × (1.27022 + 1.112624 × e ^{−0.946 × m} ) × λ ₁

  Therefore, when the equations (1) and (2) are combined and rewritten into the equation including the refractive index difference and the period dependency, the following is obtained.

λ _Edge = 1 / (1.316 + 6.1396 × e ^{−1.0374 × 2} ) × (1.316 + 6.1396 × e ^{−1.0374 × m} ) × (0.148 × Δn + 1.942) × λ ₁
= (0.6363 + 2.94 × e ^{−1.0374 × m} ) × (0.148 × Δn + 1.942) × λ ₁ (5)
λ _1/2 = 1 / (1.2702 + 1.12624 × e ^{−0.946 × 2} ) × (1.2702 + 1.12624 × e ^{−0.946 × m} ) × (0.213 × Δn + 1.234) × λ ₁
= (0.882 + 0.782 × e ^{−0.946 × m} ) × (0.213 × Δn + 1.234) × λ ₁ (6)
The above formulas (5) and (6) are obtained.

Similarly, the equations obtained by the least square method from the results shown in FIG. 15 are summarized as follows.
λ ₂ = 700 nm
λ _Edge = 574.89−380.94 × exp (−0.600 × m ′)
λ _1/2 = 583.12-167.36 × exp (−0.633 × m ′)

from now on,
λ _Edge = (0.821−0.544 × e ^{−0.600 × m ′} ) × λ ₂
λ _1/2 = (0.833−0.239 × e ^{−0.600 × m ′} ) × λ ₂
It becomes.

  Further, similarly, when m = 2, the expressions obtained by normalizing the left coefficient term to 1 are as follows.

1 / (0.821−0.544 × e ^{−0.600 × 2} ) × (0.821−0.544 × e ^{−0.600 × m ′} ) × λ ₂
1 / (0.833−0.239 × e ^{−0.600 × 2} ) × (0.833−0.239 × e ^{−0.600 × m ′} ) × λ ₂

  Therefore, when the equations (3) and (4) are combined, the equation including the refractive index difference and the period dependency is rewritten as follows.

λ _Edge = 1 / (0.821−0.544 × e ^{−0.600 × 2} ) × (0.821−0.544 × e ^{−0.600 × m ′} ) × (−0.0115 × Δn ′ + 0.668) × λ ₂
= (1.250−0.828 × e ^{−0.600 × m ′} ) × (−0.0115 × Δn ′ + 0.668) × λ ₂ (7)
λ _1/2 = 1 / (0.833−0.239 × e ^{−0.600 × 2} ) × (0.833−0.239 × e ^{−0.600 × m ′} ) × (−0.0415 × Δn ′ + 0. 807) × λ ₂
= (1.095−0.314 × e ^{−0.600 × m ′} ) × (−0.0415 × Δn ′ + 0.807) × λ ₂ (8)
The above equations (7) and (8) are obtained.

Next, the conditions under which light transmission regions can be effectively formed will be described with reference to FIG. This is shown in FIG. The wavelength at which the reflectance of 1/2 on the long wavelength side of the short wavelength peak A is λ ₃ , and the wavelength at which the reflectance at half wavelength on the short wavelength side of the long wavelength peak B is λ ₄ is λ ₄ . In addition, the center wavelength of the wavelength region to be transmitted is λ ₀ . Here, FIG. 16A shows the case where λ ₃ = λ ₀ = λ ₄ , and FIG. 16B shows the case where λ ₃ <λ ₀ <λ ₄ . Thus, it can be seen that the condition of λ ₃ <λ ₀ <λ ₄ as shown in FIG.

Here, from the equations (6) and (8),
λ ₃ = (0.882 + 0.782 × e ^{−0.946 × m} ) × (0.213 × Δn + 1.234) × λ ₁
λ ₄ = (1.095−0.314 × e ^{−0.600 × m ′} ) × (−0.0415 × Δn ′ + 0.807) × λ ₂
It becomes.

More desirably, as shown in FIG. 17, when the first bottom wavelength λ _Edge coincides with the central wavelength λ ₀ , the transmission at the central wavelength is higher, and the filter has better characteristics. That is, when the wavelength that is the bottom of the short wavelength peak A is λ ₃ and the wavelength that is the bottom on the short wavelength side of the long wavelength peak B is λ ₄ ,
λ ₃ = λ ₀ = λ ₄
It becomes.

Here, from the equations (5) and (7),
λ ₃ = (0.6363 + 2.94 × e ^{−1.0374 × m} ) × (0.148 × Δn + 1.942) × λ ₁
λ ₄ = (1.250−0.828 × e ^{−0.600 × m ′} ) × (−0.0115 × Δn ′ + 0.668) × λ ₂
It becomes.

Next, a specific filter configuration will be described. FIG. 18 is a schematic configuration diagram illustrating the filter according to the first embodiment (part 1). In the filter 10 shown in FIG. 18, silicon nitride Si _x N _y (in this embodiment, Si ₃ N ₄ (hereinafter referred to as SiN)) used in a normal Si (silicon) process is used as the material of the multilayer film. Silicon oxide SiO _x (in this embodiment, SiO ₂ is used) is used. Therefore, a multilayer film can be produced by plasma CVD (Chemical Vapor Deposition), or a vacuum overheating method or a film formation method by sputtering. Such a dielectric multilayer film is resistant to changes in diameter at high temperatures and has excellent light resistance.

In this example, the thicknesses of the SiN layer and the SiO ₂ layer are d1 and d2, respectively, corresponding to the complementary colors of R (red), G (green), and B (blue), but d1 = 81 nm corresponding to R. , D2 = 110 nm, d1 = 67 nm corresponding to G, d2 = 91 nm, d1 = 56 nm corresponding to B, and d2 = 76 nm.

  FIG. 19 shows the result of estimating the reflection spectrum when light is incident on this structure from the vertical direction by the effective Fresnel coefficient method. It can be seen from this result that the RGB ternary colors are mainly reflected.

  Further, FIG. 20 shows a transmission spectrum, which shows that light of RGB complementary colors is mainly transmitted. By manufacturing a filter having such a structure in a CCD structure as shown in FIG. 21, for example, it is possible to correspond to a complementary color filter.

FIG. 22 is a schematic configuration diagram illustrating a filter according to the first embodiment (part 2). The dielectric multilayer film of the filter shown in FIG. 22 is a combination of Si and SiO ₂ . FIG. 23 shows the reflection spectrum of the filter, and FIG. 24 shows the transmission spectrum of the filter. In the dielectric multilayer film of the filter shown in FIG. 22, the thickness is different between the lower five layers and the upper four layers. Here, as thicknesses of Si and SiO ₂ , the upper four layers are d1 and d2, respectively, and the lower five layers are d1 ′ and d2 ′, respectively. This structure corresponds to a primary color filter.

  Such a filter can be applied to a pixel arrangement structure as shown in FIG. 25, for example. In this case, since G (green) is two out of four pixels, an image with good color reproducibility can be provided without reducing the resolution in the same manner as a normal bare array.

FIG. 26 is a schematic diagram showing a CCD structure, and FIG. 27 is a schematic diagram showing a CMOS structure. After such a CCD (Charge Coupled Devices) or CMOS (Complementary Metal Oxide Semiconductor) structure circuit is formed, the SiO ₂ film and the SiN film or the SiO ₂ film and the Si ₂ film are formed on the Si photodiode by using, for example, CVD. After sequentially laminating the films, for example, a multilayer film of two of the four pixels is etched using a RIE (Reactive Ion Etching) method or the like. Furthermore, a device can be manufactured by embedding with a multilayer film having another structure and performing a planarization process.

  Next, the second embodiment will be described. The imaging device according to the second embodiment is an example in which a plurality of photodiodes are formed in the depth direction of the substrate. FIG. 28 is a conceptual diagram of a filter applied in the imaging apparatus according to the second embodiment. In the imaging apparatus according to the present embodiment, the filter 10 made of a dielectric multilayer film is used to select the wavelength of light incident on a sensor (imaging device: photodiode) that performs photoelectric conversion.

The dielectric multilayer film of the filter 10 has a structure in which a plurality of layers having different refractive indexes are stacked as shown in this figure. When light is incident on such a structure, the reflectance is reduced by the interference of light in the multilayer film. Has some dependency on. In particular, by having this multilayer film periodic structure and certain conditions (e.g., conditions of the thickness of each layer _{d d = λ 0/4 ×} n), increasing only the reflectance of a specific wavelength range of light effectively (That is, the transmittance is small) and the reflectance of light in other wavelength ranges can be lowered (that is, the transmittance is large). Here, λ ₀ is the center wavelength of a certain wavelength region, and n is the refractive index of the layer.

  For example, only a specific wavelength region such as a reflection spectrum shown in FIG. 29A can be reflected. In the present embodiment, the multilayer film is formed on the upper side of the photodiode, and a part of visible light is reflected and the remaining light is transmitted, so that the transmitted light enters the photodiode. At this time, the transmission spectrum of the multilayer film as shown in FIG.

  Further, in the photodiode portion as shown in FIG. 30, two or more sensors (here, sensors S1 and S2) are stacked in the thickness direction, and the light on the long wavelength side and the light on the short wavelength side due to the difference in absorption coefficient. And are detected by separate sensors S1 and S2.

  FIG. 31 is a diagram showing sensitivity characteristics when two sensors are arranged in the thickness direction only by the difference in absorption coefficient. In this case, it can be seen that the sensor S1 having high sensitivity on the short wavelength side and the sensor S1 having high sensitivity on the long wavelength side often generate color mixing in the portion where both sensitivities overlap, leading to deterioration of color separation characteristics.

  On the other hand, sensitivity characteristics as shown in FIG. 32 can be realized by multiplying the filter having the transmission spectrum shown in FIG. 29 and the sensor structure whose sensitivity characteristics are changed by the difference in thickness shown in FIG. Thus, not only color separation in the depth direction of the silicon substrate but also color separation using a multilayer film filter in the upper layer can provide a sensor that reduces color mixture and improves color reproduction.

  By the way, in Japanese Patent Laid-Open Nos. 2003-298038 and 2003-298102, a structure in which a color filter is arranged on the upper layer of a photodiode is proposed. However, color separation is not always good with the method using a color filter. In addition, since dyes and pigments are used, there arises a problem that changes with time such as deterioration due to light resistance and high temperatures occur. In this embodiment, since a dielectric multilayer film is used as a color separation filter, these problems can be suppressed.

Next, a specific filter configuration will be described. FIG. 33 is a schematic configuration diagram illustrating a filter according to the second embodiment (part 1). Here, as a material of the multilayer film of the filter 10, silicon nitride SiN, silicon Si, or silicon oxide SiO ₂ used in a normal Si (silicon) process is used. Therefore, the multilayer film can be produced by plasma CVD, or by a vacuum overheating method or a film formation method by sputtering. Such a dielectric multilayer film is resistant to changes in diameter at high temperatures and has excellent light resistance.

  FIG. 34 shows the result of estimating the reflection spectrum when light is incident on this structure from the vertical direction by the effective Fresnel coefficient method. From this result, it can be seen that the green color is mainly reflected. Further, FIG. 35 shows a transmission spectrum. It can be seen from this result that red and blue light are transmitted.

  Next, FIG. 37 shows the calculation results of the sensitivity characteristics of the sensors S1 and S2 estimated from the Si absorption coefficient in the sensor structure shown in FIG. Here, the sensor S1 is designed to be sensitive from the surface to a thickness of 0.5 μm, and the sensor S2 is further designed to be sensitive from a thickness of 0.5 μm to a thickness of 5 μm. Here, the sensor S2 may have a depth of 0.5 μm or more.

  Furthermore, the spectral sensitivity characteristic as shown in FIG. 38 is obtained by multiplying the filter having the transmission spectrum shown in FIG. 35 and the sensor having the sensitivity characteristic shown in FIG. Compared to the spectral sensitivity characteristic only in the depth direction (see FIG. 37), it can be seen that the spectral sensitivity characteristic shown in FIG. 38 efficiently separates B (blue) and R (red).

FIG. 39 is a schematic configuration diagram illustrating a filter according to the second embodiment (part 2). This filter structure is a combination of Si and SiO ₂ as a dielectric multilayer film. FIG. 40 shows the reflection spectrum of this filter structure, and FIG. 41 shows the transmission spectrum. Furthermore, spectral sensitivity characteristics as shown in FIG. 42 can be obtained by incorporating spectroscopy using sensors with different depths. By doing so, the separation (spectral characteristics) of B (blue) and R (red) is improved, and the problem of color mixing can be suppressed.

  The separation of B (blue) and R (red) has been mainly described above, but a G (green) pixel may be further added to the device. That is, as shown in FIG. 43 (a), the interference filter of the dielectric multilayer film and two pixels capable of separating R (red) and B (blue) in the depth direction, and the color filter or dielectric multilayer film Only two pixels that can separate G (green) are arranged.

  In the case where the filter is composed only of a dielectric multilayer film filter, for example, if a multilayer film structure as shown in FIG. 44 is used as the G (green) multilayer film, the reflection spectrum shown in FIG. 45 and the transmission spectrum shown in FIG. And serves as a G (green) filter.

  Furthermore, the pixels corresponding to G (green) can be further divided into E (emerald color) and G (green) by performing spectroscopy in the depth direction (see FIG. 43B). By performing such four-color spectroscopy of R (red), G (green), B (blue), and E (emerald), it is possible to further improve color reproducibility.

As a pixel structure to which the above filter is applied, a CCD structure as shown in FIG. 26 and a CMOS structure as shown in FIG. 27 can be cited as in the first embodiment. After such a CCD or CMOS structure circuit is formed, a SiO ₂ film and a SiN film or a SiO ₂ film and a Si film are sequentially stacked on the Si photodiode by using, for example, CVD. The multilayer film of two of the four pixels is etched using the RIE method or the like. Furthermore, a device can be manufactured by embedding with a multilayer film having another structure and performing a planarization process.

  The wavelength and the thickness, material, and refractive index of each film of the multilayer film shown in the above embodiment are examples, and the present invention is not limited to this. In the above-described embodiments, the imaging apparatus (device that converts incident light into an electrical signal) has been described. However, the filter configuration described in each embodiment is a light-emitting device that emits generated (generated) light to the outside. It can also be applied as a filter.

It is a conceptual diagram of the filter applied with the imaging device which concerns on this embodiment. It is a schematic diagram which shows the reflection and transmission spectrum of a filter. It is a schematic cross section which shows the cross-section of the imaging device which concerns on this embodiment. It is a schematic block diagram of the filter of a multilayer film structure. It is the figure (the 1) of the reflection spectrum calculated by changing the refractive index difference in the filter of a multilayer film structure. It is the figure (the 2) of the reflection spectrum calculated by changing the refractive index difference in the filter of a multilayer film structure. It is the figure (the 3) of the reflection spectrum calculated by changing the refractive index difference in the filter of a multilayer film structure. It is the figure (the 4) of the reflection spectrum calculated by changing the refractive index difference in the filter of a multilayer film structure. It is a figure which shows the half value of a reflectance. FIG. 2 is a diagram (part 1) illustrating a relationship between a refractive index difference and a wavelength. FIG. 6 is a diagram (part 2) illustrating a relationship between a refractive index difference and a wavelength. It is the figure which shows the period dependence of a reflectance (the 1). It is the figure (the 2) which shows the periodic dependence of a reflectance. It is a figure (the 1) which shows the relationship between a period and a wavelength. It is a figure (the 2) which shows the relationship between a period and a wavelength. It is FIG. (1) explaining formation of a transmissive area | region. It is FIG. (2) explaining formation of a transmissive area | region. It is a schematic block diagram explaining the filter of 1st Embodiment (the 1). It is a figure which shows the reflection spectrum of the filter of 1st Embodiment (the 1). It is a figure which shows the transmission spectrum of the filter of 1st Embodiment (the 1). It is a schematic cross section showing a CCD structure to which the filter of this embodiment is applied. It is a schematic block diagram explaining the filter of 1st Embodiment (the 2). It is a figure which shows the reflection spectrum of the filter of 1st Embodiment (the 2). It is a figure which shows the transmission spectrum of the filter of 1st Embodiment (the 2). It is a schematic diagram which shows a pixel arrangement | sequence structure. It is a schematic diagram which shows CCD structure. It is a schematic diagram which shows a CMOS structure. It is a conceptual diagram of the filter applied with the imaging device which concerns on 2nd Embodiment. It is a schematic diagram which shows the reflection and transmission spectrum of a filter. It is a schematic structure figure of the imaging device concerning a 2nd embodiment. It is a figure which shows the sensitivity characteristic with respect to a wavelength. It is a figure which shows the sensitivity characteristic at the time of combining a filter. It is a schematic block diagram explaining the filter of 2nd Embodiment (the 1). It is a figure which shows the reflection spectrum of the filter of 2nd Embodiment (the 1). It is a figure which shows the transmission spectrum of the filter of 2nd Embodiment (the 1). It is a schematic cross section of the sensor to which the filter of the second embodiment is applied. It is a figure which shows a spectral sensitivity characteristic. It is a figure which shows the spectral sensitivity characteristic at the time of combining a filter. It is a schematic block diagram explaining the filter of 2nd Embodiment (the 2). It is a figure which shows the reflection spectrum of the filter of 2nd Embodiment (the 2). It is a figure which shows the transmission spectrum of the filter of 2nd Embodiment (the 2). It is a figure which shows the spectral sensitivity characteristic at the time of combining a filter. It is a schematic diagram which shows the example of a device structure. It is a schematic cross section showing an example of a multilayer structure of a filter corresponding to G (green). It is a figure which shows the reflection spectrum of the filter corresponding to G (green). It is a figure which shows the transmission spectrum of the filter corresponding to G (green).

Explanation of symbols

  10 ... filter, 20 ... sensor, S1 ... sensor, S2 ... sensor

Claims (5)

Two or more light receiving sensors provided to be stacked at different depths of the substrate;
An interference filter composed of a dielectric multilayer film that selects a wavelength of light incident toward the two or more light receiving sensors from complementary colors for red, green, and blue ;
When the filter selects the center wavelength of light to be selected as λ, the thickness of each layer of the multilayer film as d, and the refractive index of each layer as n,
d = λ / (4 × n)
An imaging device that satisfies the requirements.   The imaging device according to claim 1, wherein the multilayer film constituting the filter is a combination of a silicon nitride film and a silicon oxide film. When the filter selects a complementary color for red, the thickness of the silicon nitride film is d1, and the thickness of the silicon oxide film is d2, so that d1 = 81 nm and d2 = 110 nm, which are within a range of ± 10%, respectively. The imaging apparatus according to claim 2. When the filter selects a complementary color for green, the thickness of the silicon nitride film is d1 and the thickness of the silicon oxide film is d2, so that d1 = 67 nm and d2 = 91 nm are within ± 10%. The imaging apparatus according to claim 2. When the filter selects a complementary color to blue, the thickness of the silicon nitride film is d1 and the thickness of the silicon oxide film is d2, so that d1 = 56 nm and d2 = 76 nm are within ± 10%. The imaging apparatus according to claim 2.

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