JP2008021866A - Solid-state imaging device - Google Patents

Abstract

The transmission characteristics of a color filter are prevented from varying from product to product while miniaturizing pixels.
A semiconductor substrate 101 having photoelectric conversion portions 103B, 103R, and 103G, and a multilayer film 106A, a spacer layer 106C, and a multilayer film 106B are sequentially stacked on the semiconductor substrate 101, and the thickness of the spacer layer 106C is photoelectrically changed. A layer 106d adjacent to the spacer layer 106C among the layers constituting the multilayer film 106A is provided with a color filter 106 that is different for each of the regions corresponding to the conversion units 103B, 103R, and 103G. Silicon nitride (Si ₃ N ₄ ) The spacer layer 106C is made of silicon dioxide (SiO ₂ ).
[Selection] Figure 2

Description

  The present invention relates to a solid-state imaging device used for a digital camera or the like, and more particularly to improvement of a color filter.

In solid-state imaging devices, color filters using organic materials are widely used (see, for example, Patent Document 1). Recently, color filters using inorganic materials have been proposed from the viewpoint of light resistance and heat resistance. (For example, see Patent Documents 2 and 3).
FIG. 14 is a schematic cross-sectional view of a solid-state imaging device according to Patent Document 3.
The color filter 606 is formed by stacking a multilayer film 606A, a spacer layer 606C, and a multilayer film 606B in this order, and the thickness of the spacer layer 606C is different for each region corresponding to the photoelectric conversion units 603B, 603R, and 603G. With this configuration, the color filter 606 can change the light transmission band for each region corresponding to the photoelectric conversion units 603B, 603R, and 603G. Usually, a lift-off method is used to form a layer having a different thickness for each region as described above (for example, Patent Document 4). However, in recent years, pixel miniaturization has progressed in the field of solid-state imaging devices, and it has become difficult to achieve a uniform thickness in each region by the lift-off method. Therefore, Patent Document 3 proposes a method of forming the spacer layer 606C using an etching technique.

FIG. 15 is a diagram illustrating a manufacturing process of a color filter according to Patent Document 3.
On the multilayer film 606A, a material constituting the spacer layer 606C is deposited to stack a layer 606u (FIG. 15A). The remaining region of the layer 606u is covered with a mask 610, and then dry etching is performed to remove unnecessary regions (FIG. 15B). After the mask 610 is peeled off, the material constituting the spacer layer 606C is deposited again to stack the layer 606v (FIG. 15C). The remaining region of the layer 606v is covered with a mask 611, and then dry etching is performed to remove unnecessary regions (FIG. 15D). The layers 606u and 606v thus formed become the spacer layer 606C. After the mask 611 is peeled off, a multilayer film 606B is stacked on the spacer layer 606C (FIG. 15E).
JP 7-311310 A JP 2000-180621 A WO / 2005/069376 JP-A-5-45514

However, when the inventors actually fabricated a solid-state imaging device using the above method, it was found that the transmission characteristics of the color filter vary from product to product. This is because when the layer to be etched (FIG. 15: 606u, 606v) is dry-etched, overetching occurs, and the surface layer portion of the underlying layer (FIG. 15: 606A) is partially removed. (See the enlarged portions of FIGS. 15B and 15D). For example, according to Patent Document 3, the layers 606u and 606v that are the layers to be etched are made of silicon dioxide (SiO ₂ ), and the layer 606d that is the base layer is made of titanium dioxide (TiO ₂ ). With this combination, the dry etching selectivity is relatively low, about 1 to 4, and overetching is likely to occur.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a solid-state imaging device capable of suppressing variation in transmission characteristics of color filters from product to product while miniaturizing pixels.

  The solid-state imaging device according to the present invention includes a semiconductor substrate having a plurality of photoelectric conversion units, and a first multilayer film, a spacer layer, and a second multilayer film sequentially stacked on the semiconductor substrate. Of the first multilayer film, one of the layered region adjacent to the spacer layer and the spacer layer is made of an oxide material. The other is made of a non-oxide material.

  The inventors can increase the dry etching selectivity if one is an oxide material and the other is a non-oxide material in the spacer layer as an etched layer and the layered region as an underlayer. Was confirmed by experiments. Therefore, by adopting the above configuration, overetching can be suppressed, and as a result, variation in transmission characteristics of the color filter from product to product can be suppressed while miniaturizing pixels.

Further, the layered region may be a layer adjacent to the spacer layer among the layers constituting the first multilayer film.
According to the above-described configuration, only the layer adjacent to the spacer layer may be selected by placing importance on the dry etching selectivity. For other layers, for example, materials can be selected from another viewpoint, such as emphasizing the refractive index. Therefore, the degree of freedom of material selection when selecting the material of the layers constituting the first multilayer film can be expanded.

  Further, the first multilayer film is formed by alternately laminating low refractive index layers and high refractive index layers, and a layer adjacent to the spacer layer among the layers constituting the first multilayer film is: The high refractive index layer other than the layer adjacent to the spacer layer among the layers constituting the first multilayer film is higher in refraction than the material constituting the layer adjacent to the spacer layer. It may be made of a material having a rate.

  According to the above configuration, since the high refractive index layer other than the layer adjacent to the spacer layer is made of a material having a higher refractive index than the material forming the layer adjacent to the spacer layer, the layer adjacent to the spacer layer is configured. Compared with the case where it consists of the same material as the material to perform, the thickness of the whole color filter can be made thin. As a result, color mixing caused by obliquely incident light can be suppressed.

The second multilayer film has the same number of layers as the first multilayer film, and the second multilayer film and the first multilayer film are arranged in the stacking direction with respect to the thickness and constituent material of each layer. It is good also as having a mirror-symmetrical relationship.
The inventors have confirmed through experiments that the transmittance peak can be increased by making the configuration of the first multilayer film and the configuration of the second multilayer film mirror-symmetrical. Therefore, the sensitivity of the solid-state imaging device can be increased by adopting the above configuration.

The oxide material may be silicon dioxide or titanium dioxide, and the non-oxide material may be silicon nitride.
The inventors have confirmed through experiments that the selective ratio between silicon dioxide and silicon nitride and the selective ratio between titanium dioxide and silicon nitride are 10 or more under predetermined dry etching conditions. According to the above configuration, since a large selection ratio of 10 or more can be obtained, it is possible to suppress variation in the transmission characteristics of the color filter from product to product while miniaturizing pixels.

The layered region may be a portion adjacent to the spacer layer among layers adjacent to the spacer layer in the first multilayer film.
According to the above configuration, the constituent material may be selected by placing importance on the dry etching selectivity only for the portion adjacent to the spacer layer among the layers adjacent to the spacer layer. For other portions of the layer adjacent to the spacer layer and layers other than the layer adjacent to the spacer layer, materials can be selected from another viewpoint, for example, emphasizing the refractive index. Therefore, the degree of freedom of material selection when selecting the material of the layers constituting the first multilayer film can be expanded.

  Further, the first multilayer film is formed by alternately laminating low refractive index layers and high refractive index layers, and a layer adjacent to the spacer layer among the layers constituting the first multilayer film is: A layer that is a high-refractive index layer and is adjacent to the spacer layer, of a layer adjacent to the spacer layer, other than a portion adjacent to the spacer layer, and of the layers constituting the first multilayer film The other high refractive index layer may be made of a material having a higher refractive index than the material constituting the portion adjacent to the spacer layer.

  According to the above configuration, the portion of the layer adjacent to the spacer layer other than the portion adjacent to the spacer layer and the high refractive index layer other than the layer adjacent to the spacer layer constitute a portion adjacent to the spacer layer. Since it consists of material which has a refractive index higher than material, compared with the case where it consists of the same material as the material which comprises the site | part adjacent to a spacer layer, the thickness of the whole color filter can be made thin. As a result, color mixing caused by obliquely incident light can be suppressed.

The best mode for carrying out the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 is a diagram showing a schematic configuration of a solid-state imaging device according to the present invention.
The solid-state imaging device 1 includes a pixel 2, a vertical shift register 3, a horizontal shift register 4, and a drive circuit 5. The pixels 2 are two-dimensionally arranged, and only the pixels selected by the vertical shift register 3 and the horizontal shift register 4 output pixel signals. The vertical shift register 3 and the horizontal shift register 4 are driven by a drive circuit 5.

FIG. 2 is a schematic cross-sectional view of the solid-state imaging device according to Embodiment 1 of the present invention.
The solid-state imaging device 1 includes a semiconductor substrate 101 and a color filter 106 as main components. The semiconductor substrate 101 includes a well 102, and photoelectric conversion units 103B, 103R, and 103G are included in the well 102. The color filter 106 is disposed on the semiconductor substrate 101 with the interlayer insulating film 104 interposed therebetween. A light shielding film 105 is disposed in the interlayer insulating film 104. A planarizing layer 107 is laminated on the color filter 106, and a microlens 108 is disposed thereon.

The color filter 106 has a structure in which a multilayer film 106A, a spacer layer 106C, and a multilayer film 106B are sequentially stacked.
The multilayer film 106A is a so-called λ / 4 multilayer film, and has a structure in which low refractive index layers 106a and 106c and high refractive index layers 106b and 106d are alternately stacked. Similarly, the multilayer film 106B is a λ / 4 multilayer film, and has a structure in which low refractive index layers 106f and 106h and high refractive index layers 106e and 106g are alternately stacked. The optical film thickness nd (n: refractive index, d: physical film thickness) of each layer is set to be λ / 4. Here, the wavelength λ is the center wavelength of the reflection band. The spacer layer 106C is disposed between the multilayer films 106A and 106B, and is formed to have a different thickness for each region corresponding to each of the photoelectric conversion units 103B, 103R, and 103G.

Since the color filter 106 has the above structure, the color filter 106 transmits light in a band corresponding to the thickness of the spacer layer 106C and does not transmit light in other bands.
In the first embodiment, the constituent materials of the layers are silicon dioxide (SiO ₂ ) for the low refractive index layers 106a, 106c, 106f, and 106h, titanium dioxide (TiO ₂ ) for the high refractive index layers 106b, 106e, and 106g, The high refractive index layer 106d is made of silicon nitride (Si ₃ N ₄ ). The constituent material of the spacer layer 106C is silicon dioxide (SiO ₂ ).

  In the first embodiment, the center wavelength λ is designed to be 530 nm. The thickness (physical film thickness) of each layer is 91 nm for the low refractive index layers 106a, 106c, 106f, and 106h and the high refractive index layers 106b, 106e, and 106g in consideration of the center wavelength λ and the refractive index of each material. The thickness is 52 nm, and the high refractive index layer 106d is 66 nm. Here, the refractive index of each material is 1.45 for silicon dioxide, 2.0 for silicon nitride, and 2.53 for titanium dioxide. The thickness (physical film thickness) of the spacer layer 106C is 125 nm in the region corresponding to the photoelectric conversion unit 103B, 35 nm in the region corresponding to the photoelectric conversion unit 103R, and 0 nm in the region corresponding to the photoelectric conversion unit 103G.

FIG. 3 is a diagram showing the transmission characteristics of the color filter 106 according to Embodiment 1 of the present invention.
The transmittance shown here is derived by the matrix method using the Fresnel coefficient. The transmittance curves 10B, 10G, and 10R represent the transmittance of the region corresponding to the photoelectric conversion unit 103B, the region corresponding to the photoelectric conversion unit 103G, and the region corresponding to the photoelectric conversion unit 103R in the color filter 106, respectively. . According to this, in the color filter 106, the region corresponding to the photoelectric conversion unit 103B, the region corresponding to the photoelectric conversion unit 103G, and the region corresponding to the photoelectric conversion unit 103R are about 450 nm (see the curve 10B) and about 530 nm, respectively. (Refer to curve 10G) and has a transmission characteristic in a band having a central wavelength of about 600 nm (see curve 10R).

4 and 5 are diagrams showing a manufacturing process of the color filter 106 according to the first embodiment of the present invention.
First, on the interlayer insulating film 104, a low refractive index layer 106a, a high refractive index layer 106b, a low refractive index layer 106c, and a high refractive index layer 106d are sequentially stacked. These become the multilayer film 106A. A layer 106u is stacked on the multilayer film 106A (FIG. 4A).

  The low refractive index layers 106a and 106c are formed by depositing silicon dioxide using a high frequency sputtering apparatus. The high refractive index layer 106b is formed by depositing titanium dioxide using a high frequency sputtering apparatus. The high refractive index layer 106d is formed by depositing silicon nitride using a CVD (Chemical Vapor Deposition) apparatus. The layer 106u is formed by depositing silicon dioxide using a high frequency sputtering apparatus. The thickness of the layer 106u is 80 nm.

Next, the remaining region of the layer 106u is covered with a mask 110, and then dry etching is performed to remove unnecessary regions (FIG. 4B). As the etching gas, C ₅ F ₈ + O ₂ or C ₄ F ₆ + O ₂ is used.
Next, after removing the mask 110, a layer 106v is stacked on the multilayer film 106A (FIG. 4C). The layer 106v is formed by depositing silicon dioxide using a high frequency sputtering apparatus. The thickness of the layer 106v is 35 nm. The layers 106u and 106v become the spacer layer 106C.

Next, the remaining region of the layer 106v is covered with a mask 111, and then dry etching is performed to remove unnecessary regions (FIG. 5A). As the etching gas, C ₅ F ₈ + O ₂ or C ₄ F ₆ + O ₂ is used.
Next, after removing the mask 111, a high refractive index layer 106e is laminated on the multilayer film 106A (FIG. 5B), and further, a low refractive index layer 106f, a high refractive index layer 106g, and a low refractive index layer. 106h are laminated in order (FIG. 5C). The high refractive index layers 106e and 106g are formed by depositing titanium dioxide using a high frequency sputtering apparatus. The low refractive index layers 106f and 106h are formed by depositing silicon dioxide using a high frequency sputtering apparatus. In this way, the color filter 106 is formed.

As described above, when dry etching is performed on the layers 106u and 106v, the high refractive index layer 106d serves as a base. In the first embodiment, the layers 106u and 106v are made of silicon dioxide, and the high refractive index layer 106d is made of silicon nitride.
The inventors have confirmed through experiments that the selection ratio of silicon nitride to silicon dioxide is 1:20 when the etching gas is C ₅ F ₈ + O ₂ or C ₄ F ₆ + O ₂ . On the other hand, in the prior art, the etching gas is CF ₄ + O ₂ and the selection ratio of titanium dioxide to silicon dioxide is 1: 1 to 4. As described above, in the first embodiment, the selection ratio of dry etching can be increased as compared with the conventional technique, so that over-etching is suppressed (manufacturing error is 1% or less), and as a result, the transmission characteristics of the color filter. Can be prevented from varying from product to product.
(Embodiment 2)
The second embodiment is different from the first embodiment in that the two multilayer films facing each other with the spacer layer interposed therebetween have a mirror-symmetrical relationship in the stacking direction with respect to the thickness and constituent material of each layer.

FIG. 6 is a schematic cross-sectional view of a solid-state imaging device according to Embodiment 2 of the present invention.
The color filter 206 has a structure in which a multilayer film 206A, a spacer layer 206C, and a multilayer film 206B are sequentially stacked.
In the second embodiment, the constituent material of each layer is silicon dioxide (SiO ₂ ) for the low refractive index layers 206a, 206c, 206f, and 206h, titanium dioxide (TiO ₂ ) for the high refractive index layers 206b and 206g, and high refractive index. The rate layers 206d and 206e are made of silicon nitride (Si ₃ N ₄ ). The constituent material of the spacer layer 206C is silicon dioxide (SiO ₂ ).

  In the second embodiment, the thickness (physical film thickness) of the high refractive index layer 206e is 66 nm in consideration of the center wavelength λ and the refractive index of each material. The thickness (physical film thickness) of the spacer layer 206C is 120 nm in the region corresponding to the photoelectric conversion unit 203B, 42 nm in the region corresponding to the photoelectric conversion unit 203R, and 0 nm in the region corresponding to the photoelectric conversion unit 203G. The thickness of the other layers is the same as that in the first embodiment.

FIG. 7 is a diagram showing the transmission characteristics of the color filter 206 according to Embodiment 2 of the present invention.
The transmittance curves 20B, 20G, and 20R represent the transmittances of the region corresponding to the photoelectric conversion unit 203B, the region corresponding to the photoelectric conversion unit 203G, and the region corresponding to the photoelectric conversion unit 203R in the color filter 206, respectively. . According to this, the transmission band in each region of the color filter 206 is the same as that in the first embodiment, but the transmittance in each region is higher than that in the first embodiment (first embodiment). : About 85%, Embodiment 2: about 97%). Therefore, in Embodiment 2, in addition to the effect shown in Embodiment 1, the effect that the sensitivity of a solid-state imaging device can be improved can be acquired.
(Embodiment 3)
In the third embodiment, the configuration of the layer adjacent to the spacer layer among the layers constituting the multilayer film is different from that in the first embodiment.

FIG. 8 is a schematic cross-sectional view of a solid-state imaging device according to Embodiment 3 of the present invention.
The color filter 306 has a structure in which a multilayer film 306A, a spacer layer 306C, and a multilayer film 306B are sequentially stacked.
In Embodiment 3, the constituent material of each layer is silicon dioxide (SiO ₂ ) for the low refractive index layers 306a, 306c, 306f, and 306h, titanium dioxide (TiO ₂ ) for the high refractive index layers 306b, 306e, and 306g, The high refractive index layer 306d is made of silicon nitride (Si ₃ N ₄ ) and titanium dioxide (TiO ₂ ). The constituent material of the spacer layer 306C is silicon dioxide (SiO ₂ ).

In the third embodiment, the portion 306d2 adjacent to the spacer layer 306C in the high refractive index layer 306d is made of silicon nitride, and the other portion 306d1 is made of titanium dioxide.
In Embodiment 3, the thickness (physical film thickness) of the portion 306d2 in the high refractive index layer 306d is 10 nm, and the thickness (physical film thickness) of the portion 306d1 is 44 nm. The thickness (physical film thickness) of the spacer layer 306C is 134 nm in the region corresponding to the photoelectric conversion unit 303B, 33 nm in the region corresponding to the photoelectric conversion unit 303R, and 0 nm in the region corresponding to the photoelectric conversion unit 303G. The thickness of the other layers is the same as that in the first embodiment.

FIG. 9 is a diagram showing the transmission characteristics of the color filter 306 according to Embodiment 3 of the present invention.
The transmittance curves 30B, 30G, and 30R represent the transmittance of the region corresponding to the photoelectric conversion unit 303B, the region corresponding to the photoelectric conversion unit 303G, and the region corresponding to the photoelectric conversion unit 303R in the color filter 306, respectively. . According to this, the transmission band in each region of the color filter 306 is the same as that in the first embodiment, but the transmittance in each region is higher than that in the first embodiment (first embodiment). : About 85%, Embodiment 3: 95% or more). Therefore, the third embodiment can obtain the effect that the sensitivity of the solid-state imaging device can be increased in addition to the effect shown in the first embodiment. It is considered that such an effect can be obtained because not only silicon nitride but also titanium dioxide having a higher refractive index than silicon nitride is used as a constituent material of the high refractive index layer 306d.

In this example, the thickness (physical film thickness) of the portion 306d2 of the high refractive index layer 306d is 10 nm, and the thickness (physical film thickness) of the portion 306d1 is 44 nm. This value is derived in consideration of the following two conditions. (1) In order for the portion 306d2 to function as an etching stop layer, it is necessary to set the thickness to at least 10 nm. (2) In order to improve the transmission characteristics, it is necessary to make the portion 306d1 made of titanium dioxide as thick as possible. By doing so, it is possible to improve the transmission characteristics as much as possible while suppressing over-etching.
(Embodiment 4)
The fourth embodiment is different from the third embodiment in that the two multilayer films facing each other with the spacer layer interposed therebetween have a mirror-symmetrical relationship in the stacking direction with respect to the thickness and constituent material of each layer.

FIG. 10 is a schematic cross-sectional view of a solid-state imaging device according to Embodiment 4 of the present invention.
The color filter 406 has a structure in which a multilayer film 406A, a spacer layer 406C, and a multilayer film 406B are sequentially stacked.
In Embodiment 4, the constituent material of each layer is silicon dioxide (SiO ₂ ) for the low refractive index layers 406a, 406c, 406f, and 406h, titanium dioxide (TiO ₂ ) for the high refractive index layers 406b and 406g, and high refractive index. The rate layers 406d and 406e are made of silicon nitride (Si ₃ N ₄ ) and titanium dioxide (TiO ₂ ). The constituent material of the spacer layer 406C is silicon dioxide (SiO ₂ ).

In the fourth embodiment, the portion 406e2 adjacent to the spacer layer 406C in the high refractive index layer 406e is made of silicon nitride, and the other portion 406e1 is made of titanium dioxide.
In Embodiment 4, the thickness (physical film thickness) of the portion 406e2 in the high refractive index layer 406e is 10 nm, and the thickness (physical film thickness) of the portion 406e1 is 44 nm. The thickness of the other layers is the same as that in the third embodiment.

FIG. 11 is a diagram showing the transmission characteristics of the color filter 406 according to Embodiment 4 of the present invention.
The transmittance curves 40B, 40G, and 40R represent the transmittance of the region corresponding to the photoelectric conversion unit 403B, the region corresponding to the photoelectric conversion unit 403G, and the region corresponding to the photoelectric conversion unit 403R in the color filter 406, respectively. . According to this, the transmission band in each region of the color filter 406 is the same as that in the third embodiment, but the transmittance in the long wavelength region is higher than that in the third embodiment (the embodiment). 3) 30R: about 95%, and Embodiment 4 40R: about 97%). Therefore, in the fourth embodiment, in addition to the effect shown in the third embodiment, an effect that the sensitivity of the solid-state imaging device can be increased particularly in the long wavelength region can be obtained.
(Embodiment 5)
The fifth embodiment is different from the first embodiment in which the constituent material of the layer adjacent to the spacer layer is changed in that the constituent material of the spacer layer is changed with respect to the prior art.

FIG. 12 is a schematic cross-sectional view of a solid-state imaging device according to Embodiment 5 of the present invention.
The color filter 506 has a structure in which a multilayer film 506A, a spacer layer 506C, and a multilayer film 506B are sequentially stacked.
The multilayer film 506A is a so-called λ / 4 multilayer film, and has a structure in which low refractive index layers 506a and 506c and high refractive index layers 506b and 506d are alternately stacked. Similarly, the multilayer film 506B is a λ / 4 multilayer film and has a structure in which low refractive index layers 506f and 506h and high refractive index layers 506e and 506g are alternately stacked. The optical film thickness nd (n: refractive index, d: physical film thickness) of each layer is set to be λ / 4. Here, the wavelength λ is the center wavelength of the reflection band. The spacer layer 506C is disposed between the multilayer films 506A and 506B, and is formed to have a different thickness for each region corresponding to each of the photoelectric conversion units 503B, 503R, and 503G.

Since the color filter 506 has the above-described structure, the color filter 506 transmits light in a band corresponding to the thickness of the spacer layer 506C and does not transmit light in other bands.
In the fifth embodiment, the constituent material of each layer is silicon dioxide (SiO ₂ ) for the low refractive index layers 506a, 506c, 506f, and 506h, and titanium dioxide (TiO ₂ ) for the high refractive index layers 506b, 506d, 506e, and 506g. ). The constituent material of the spacer layer 506C is silicon nitride (Si ₃ N ₄ ).

  In the fifth embodiment, the center wavelength λ is designed to be 530 nm. The thickness (physical film thickness) of each layer is 91 nm for the low refractive index layers 506a, 506c, 506f, and 506h and the high refractive index layers 506b, 506d, 506e, and 506g in consideration of the center wavelength λ and the refractive index of each material. Is set to 52 nm. Here, the refractive index of each material is 1.45 for silicon dioxide, 2.0 for silicon nitride, and 2.53 for titanium dioxide. The thickness (physical film thickness) of the spacer layer 506C is 90 nm in the region corresponding to the photoelectric conversion unit 503B, 31 nm in the region corresponding to the photoelectric conversion unit 503R, and 0 nm in the region corresponding to the photoelectric conversion unit 503G.

FIG. 13 is a diagram showing the transmission characteristics of the color filter 506 according to Embodiment 5 of the present invention.
The transmittance curves 50B, 50G, and 50R represent the transmittance of the region corresponding to the photoelectric conversion unit 503B, the region corresponding to the photoelectric conversion unit 503G, and the region corresponding to the photoelectric conversion unit 503R in the color filter 506, respectively. . According to this, in the color filter 506, the region corresponding to the photoelectric conversion unit 503B, the region corresponding to the photoelectric conversion unit 503G, and the region corresponding to the photoelectric conversion unit 503R are about 450 nm (see the curve 50B) and about 530 nm, respectively. (Refer to curve 50G) and has a transmission characteristic in a band having a central wavelength of about 600 nm (see curve 50R).

The manufacturing method of the color filter according to the fifth embodiment is the same as that of the first embodiment, except that the constituent materials of the spacer layer 506C and the high refractive index layer 506d are different from those of the first embodiment. Different from the first embodiment.
In the fifth embodiment, the layer to be etched is made of silicon nitride, and the base layer is made of titanium dioxide. As the etching gas, CF ₄ + O ₂ is used.

The inventors have confirmed by experiments that the etching gas is CF ₄ + O ₂ , and the selection ratio of titanium dioxide to silicon nitride is 1:20. On the other hand, in the prior art, the etching gas is CF ₄ + O ₂ and the selection ratio of titanium dioxide to silicon dioxide is 1: 1 to 4. As described above, in the fifth embodiment, the selection ratio of dry etching can be increased as compared with the conventional technique, so that over-etching is suppressed (manufacturing error is 1% or less), and as a result, transmission characteristics of the color filter. Can be prevented from varying from product to product.

Furthermore, in the fifth embodiment, since the constituent material of the spacer layer 506C is silicon nitride having a refractive index higher than that of silicon dioxide, the thickness of the entire color filter can be reduced as compared with the conventional technique (compared with the conventional technique). 44 nm, 49 nm thinner than in the first embodiment). Therefore, it is possible to suppress color mixing that occurs due to light incident obliquely.
Although the solid-state imaging device according to the present invention has been described based on the embodiments, the present invention is not limited to these embodiments. For example, the following modifications can be considered.
(1) The inventors used an ICP dry etching apparatus, etching conditions were as follows: reaction pressure: 70 mmTorr, upper power: 700 mW, lower power: 50 mW, and an etching gas of CF ₄ + O _2. Experiments confirmed that the selection ratio of SiO ₂ ), silicon nitride (Si ₃ N ₄ ), and titanium dioxide (TiO ₂ ) was 2: 20: 1. From this experimental result, it can be seen that the dry etching selectivity is small between oxide materials and large between oxide materials and non-oxide materials.

Therefore, in the embodiment, only combinations using silicon dioxide (SiO ₂ ) and titanium dioxide (TiO ₂ ) as oxide materials and silicon nitride (Si ₃ N ₄ ) as non-oxide materials are listed. However, the present invention is not limited to this example. For example, tantalum oxide (Ta ₂ O ₅ ), zirconium oxide (ZrO ₂ ), aluminum oxide (Al ₂ O ₃ ), hafnium oxide (HfO ₃ ), magnesium oxide (MgO ₂ ), etc. are used as the oxide material. Silicon oxide (SiN), magnesium fluoride (MgF ₂ ), or the like may be employed as the oxide material.
(2) As a layered region adjacent to the spacer layer in the multilayer film, the high refractive index layer 106d is cited in the first embodiment, and the portion 306d2 of the high refractive index layer 306d is cited in the third embodiment. The present invention is not limited to this example. For example, the layers 106d and 106c may be layered regions, or all the layers of the multilayer film 106A may be layered regions.

  The present invention can be applied to, for example, a digital camera.

It is a figure which shows schematic structure of the solid-state imaging device concerning this invention. 1 is a schematic cross-sectional view of a solid-state imaging device according to Embodiment 1 of the present invention. It is a figure which shows the permeation | transmission characteristic of the color filter 106 which concerns on Embodiment 1 of this invention. It is a figure which shows the manufacture process of the color filter 106 which concerns on Embodiment 1 of this invention. It is a figure which shows the manufacture process of the color filter 106 which concerns on Embodiment 1 of this invention. It is a cross-sectional schematic diagram of the solid-state imaging device which concerns on Embodiment 2 of this invention. It is a figure which shows the permeation | transmission characteristic of the color filter 206 which concerns on Embodiment 2 of this invention. It is a cross-sectional schematic diagram of the solid-state imaging device which concerns on Embodiment 3 of this invention. It is a figure which shows the permeation | transmission characteristic of the color filter 306 which concerns on Embodiment 3 of this invention. It is a cross-sectional schematic diagram of the solid-state imaging device which concerns on Embodiment 4 of this invention. It is a figure which shows the permeation | transmission characteristic of the color filter 406 which concerns on Embodiment 4 of this invention. It is a cross-sectional schematic diagram of the solid-state imaging device which concerns on Embodiment 5 of this invention. It is a figure which shows the permeation | transmission characteristic of the color filter 506 which concerns on Embodiment 5 of this invention. It is a cross-sectional schematic diagram of the solid-state imaging device concerning patent document 3. It is a figure which shows the manufacture process of the color filter which concerns on patent document 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid-state imaging device 2 Pixel 3 Vertical shift register 4 Horizontal shift register 5 Drive circuit 101,201,301,401,501,601 Semiconductor substrate 102,202,302,402,502,602 Well 103,203,303,403, 503, 603 Photoelectric conversion unit 104, 204, 304, 404, 504, 604 Interlayer insulating film 105, 205, 305, 405, 505, 605 Light shielding film 106, 206, 306, 406, 506, 606 Color filter 106A, 206A, 306A, 406A, 506A, 606A Multilayer film 106B, 206B, 306B, 406B, 506B, 606B Multilayer film 106C, 206C, 306C, 406C, 506C, 606C Spacer layer 106a, 206a, 306a, 406a, 506a, 606a Low refractive index layer 106b, 206b, 306b, 406b, 506b, 606b High refractive index layer 106c, 206c, 306c, 406c, 506c, 606c Low refractive index layer 106d, 206d, 306d, 406d, 506d, 606d High refractive index layer 106e, 206e, 306e, 406e, 506e, 606e High refractive index layer 106f, 206f, 306f, 406f, 506f, 606f Low refractive index layer 106g, 206g, 306g, 406g, 506g, 606g High refractive index layer 106h, 206h, 306h , 406h, 506h, 606h Low refractive index layer 107 Flattening layer 108 Micro lens 110, 111, 610, 611 Mask

Claims (9)

A semiconductor substrate having a plurality of photoelectric conversion parts;
A color filter in which a first multilayer film, a spacer layer, and a second multilayer film are sequentially stacked on the semiconductor substrate, and the thickness of the spacer layer is made different for each photoelectric conversion unit corresponding region,
One of the layered region adjacent to the spacer layer and the spacer layer in the first multilayer film is made of an oxide material, and the other is made of a non-oxide material. The solid-state imaging device according to claim 1, wherein the layered region is a layer adjacent to the spacer layer among layers constituting the first multilayer film. The first multilayer film is formed by alternately laminating low refractive index layers and high refractive index layers,
Of the layers constituting the first multilayer film, a layer adjacent to the spacer layer is a high refractive index layer,
Of the layers constituting the first multilayer film, the high refractive index layer other than the layer adjacent to the spacer layer is made of a material having a higher refractive index than the material constituting the layer adjacent to the spacer layer. The solid-state imaging device according to claim 2. The second multilayer film has the same number of layers as the first multilayer film,
4. The solid-state imaging device according to claim 3, wherein the second multilayer film and the first multilayer film have a mirror symmetry relationship in the stacking direction with respect to the thickness and constituent material of each layer. The oxide material is silicon dioxide or titanium dioxide,
The solid-state imaging device according to claim 3 or 4, wherein the non-oxide material is silicon nitride. The solid-state imaging device according to claim 1, wherein the layered region is a portion adjacent to the spacer layer among layers adjacent to the spacer layer in the first multilayer film. The first multilayer film is formed by alternately laminating low refractive index layers and high refractive index layers,
Of the layers constituting the first multilayer film, a layer adjacent to the spacer layer is a high refractive index layer,
Of the layer adjacent to the spacer layer, the portion other than the portion adjacent to the spacer layer and the high refractive index layer other than the layer adjacent to the spacer layer of the layers constituting the first multilayer film are The solid-state imaging device according to claim 6, wherein the solid-state imaging device is made of a material having a higher refractive index than a material constituting a portion adjacent to the spacer layer. The second multilayer film has the same number of layers as the first multilayer film,
The solid-state imaging device according to claim 7, wherein the second multilayer film and the first multilayer film have a mirror-symmetrical relationship in the stacking direction with respect to the thickness and constituent material of each layer. The oxide material is silicon dioxide or titanium dioxide,
The solid-state imaging device according to claim 7, wherein the non-oxide material is silicon nitride.

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