Method for manufacturing filter for solid-state imaging device and method for manufacturing solid-state imaging device

Abstract

The method includes the steps of forming a color filter on a semiconductor substrate; forming an etching stop layer on the semiconductor substrate and the color filter; forming an infrared light cut-off precursor layer on the etching stop layer; forming a resist pattern covering a portion of the infrared light cut-off precursor layer on the color filter; and forming an infrared light cut-off filter by dry etching the infrared light cut-off precursor layer using the resist pattern, the etching rate of the dry etched infrared light cut-off precursor layer being different from the etching rate of the etching stop layer.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for manufacturing a filter for a solid-state imaging device and a method for manufacturing a solid-state imaging device. BACKGROUND

[0002] A solid-state imaging device such as a CMOS image sensor and a CCD image sensor has a photoelectric conversion element that converts the intensity of light into an electric signal. As one example of a solid-state imaging device, light corresponding to different colors can be detected. The solid-state imaging device has a color filter for each color and a photoelectric conversion element corresponding to each color filter, and light of mutually different colors is detected by each photoelectric conversion element (for example, refer to Patent Literature 1). Another example of a solid-state imaging device has an organic photoelectric conversion element and an inorganic photoelectric conversion element, and light of mutually different colors is detected by each photoelectric conversion element without using a color filter (for example, refer to Patent Literature 2).

[0003] A solid-state imaging device has an infrared light-cutting filter on a photoelectric conversion element. The infrared light-cutting filter contains an infrared light-absorbing pigment that absorbs infrared light, thereby cutting the infrared light that can be detected by each photoelectric conversion element with respect to the photoelectric conversion element. Thus, the detection accuracy of visible light by each photoelectric conversion element can be improved. The infrared light-cutting filter contains, for example, a cyanine pigment as an infrared light-absorbing pigment (for example, refer to Patent Literature 3).

[0004] Patent Literature 1: Japanese Patent Application Publication No. 2003-060176

[0005] Patent Literature 2: Japanese Patent Application Publication No. 2018-060910

[0006] Patent Literature 3: Japanese Patent Application Publication No. 2007-219114 SUMMARY

[0007] However, for the manufacture of a solid-state imaging device having a fine pixel, a dry etching method is proposed as a processing method for forming each layer of the solid-state imaging device. In the dry etching method, an etchant in plasma collides with an etching object to remove a part of the etching object. In the dry etching method, dry etching processing is continued against the etching object for a certain period after the lower layer of the etching object is exposed for the purpose of improving the processing accuracy of dry etching. In this case, the etchant against the etching object also collides with the lower layer of the etching object to change the properties of the surface of the lower layer. Thus, the function of the solid-state imaging device sometimes deteriorates.

[0008] An object of the present application is to provide a method for manufacturing a filter for a solid-state imaging device and a method for manufacturing a solid-state imaging device that can suppress the deterioration of the function due to the change in the properties of the surface of the lower layer of the etching object.

[0009] A method for manufacturing a filter for a solid-state imaging device, for solving the above problems, includes the steps of: forming a color filter on a semiconductor substrate; forming an etching stopper layer on the semiconductor substrate and the color filter; forming an infrared light cut-off precursor layer on the etching stopper layer; forming a resist pattern covering a portion of the infrared light cut-off precursor layer on the color filter; and forming an infrared light cut-off filter by dry etching the infrared light cut-off precursor layer using the resist pattern, the etching rate of the infrared light cut-off precursor layer being different from the etching rate of the etching stopper layer.

[0010] A method for manufacturing a solid-state imaging device, for solving the above problems, includes the steps of: preparing a semiconductor substrate; and manufacturing a filter for a solid-state imaging device by the method for manufacturing a filter for a solid-state imaging device.

[0011] According to the method for manufacturing a filter for a solid-state imaging device and the method for manufacturing a solid-state imaging device, even if a portion of the infrared light cut-off precursor layer is removed by over-etching of the infrared light cut-off precursor layer, the etching stopper layer is located under the infrared light cut-off precursor layer, so that the collision of the etchant against the lower layer of the etching stopper layer can be suppressed. Thus, the degradation of the function of the solid-state imaging device due to the change in the surface properties of the lower layer of the infrared light cut-off precursor layer as the etching target can be suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is an exploded perspective view showing the configuration of the solid-state imaging device of Embodiment 1.

[0013] Figure 2 is a process diagram for explaining the method for manufacturing the solid-state imaging device of Embodiment 1.

[0014] Figure 3 is a process diagram for explaining the method for manufacturing the solid-state imaging device of Embodiment 1.

[0015] Figure 4 is a process diagram for explaining the method for manufacturing the solid-state imaging device of Embodiment 1.

[0016] Figure 5 is a process diagram for explaining the method for manufacturing the solid-state imaging device of Embodiment 1.

[0017] Figure 6 is a process diagram for explaining the method for manufacturing the solid-state imaging device of Embodiment 1.

[0018] Figure 7is a process diagram for explaining the manufacturing method of the solid-state imaging device of the first embodiment.

[0019] Figure 8 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the first embodiment.

[0020] Figure 9 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the first embodiment.

[0021] Figure 10 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the first embodiment.

[0022] Figure 11 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the first embodiment.

[0023] Figure 12 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the first embodiment.

[0024] Figure 13 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the second embodiment.

[0025] Figure 14 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the second embodiment.

[0026] Figure 15 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the second embodiment.

[0027] Figure 16 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the second embodiment.

[0028] Figure 17 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the second embodiment.

[0029] Figure 18 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the third embodiment.

[0030] Figure 19 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the third embodiment.

[0031] Figure 20 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the fourth embodiment.

[0032] Figure 21is a process diagram for explaining the manufacturing method of the solid-state imaging device of the 4th embodiment.

[0033] Figure 22 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the 4th embodiment.

[0034] Figure 23 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the 4th embodiment.

[0035] Figure 24 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the 4th embodiment.

[0036] Figure 25 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the 4th embodiment.

[0037] Figure 26 is a process diagram for explaining the manufacturing method of the solid-state imaging device of the 4th embodiment. DETAILED DESCRIPTION

[0038] [1st Embodiment]

[0039] Reference Figures 1 to 12 A first embodiment of a manufacturing method of a solid-state imaging device filter and a manufacturing method of a solid-state imaging device will be explained. Hereinafter, the solid-state imaging device and the manufacturing method of the solid-state imaging device will be explained in order. Further, in the present embodiment, infrared light is light having a wavelength included in a range of greater than or equal to 0.7 μm and less than or equal to 1 mm, and near-infrared light is light having a wavelength included in a range of greater than or equal to 700 nm and less than or equal to 1100 nm among the infrared light.

[0040] [Solid-state imaging device]

[0041] Reference Figure 1 A solid-state imaging device will be explained. Figure 1 is a schematic configuration diagram separately showing each layer of a part of the solid-state imaging device.

[0042] As Figure 1 shown, the solid-state imaging device 10 has a solid-state imaging device filter 10F and a plurality of photoelectric conversion elements 11. The plurality of photoelectric conversion elements 11 have a red photoelectric conversion element 11R, a green photoelectric conversion element 11G, a blue photoelectric conversion element 11B, and an infrared light photoelectric conversion element 11P.

[0043] The solid-state imaging device 10 has a plurality of red photoelectric conversion elements 11R, a plurality of green photoelectric conversion elements 11G, a plurality of blue photoelectric conversion elements 11B, and a plurality of infrared light photoelectric conversion elements 11P. The plurality of infrared light photoelectric conversion elements 11P measure the intensity of infrared light. Further, in Figure 1 In the drawing, a repeating unit of the photoelectric conversion elements 11 of the solid-state imaging device 10 is shown for convenience of illustration.

[0044] The solid-state imaging device filter 10F has a plurality of visible light filters, an infrared light band pass filter 12P, an etching stopper layer 13, an infrared light cut filter 14, an oxygen barrier layer 15, a plurality of visible light microlenses, and an infrared light microlens 16P.

[0045] The visible light color filter is composed of a red filter 12R, a green filter 12G, and a blue filter 12B. The red filter 12R is located on the light incident side with respect to the red photoelectric conversion element 11R. The green filter 12G is located on the light incident side with respect to the green photoelectric conversion element 11G. The blue filter 12B is located on the light incident side with respect to the blue photoelectric conversion element 11B.

[0046] The infrared light band pass filter 12P is located on the light incident side with respect to the infrared light photoelectric conversion element 11P. The infrared light band pass filter 12P cuts off visible light that can be detected by the infrared light photoelectric conversion element 11P with respect to the infrared light photoelectric conversion element 11P. That is, the visible light that is incident on the infrared light band pass filter 12P is suppressed from being transmitted through the infrared light band pass filter 12P. Thus, the detection accuracy of the infrared light photoelectric conversion element 11P is improved. The infrared light that can be detected by the infrared light photoelectric conversion element 11P is, for example, near infrared light.

[0047] The etching stopper layer 13 is located on the light incident side with respect to each of the color filters 12R, 12G, and 12B. The etching stopper layer 13 has a through hole 13H. From a viewpoint opposite to the plane on which the etching stopper layer 13 is expanded, the infrared light band pass filter 12P is located within the region divided by the through hole 13H. On the other hand, from the viewpoint opposite to the plane on which the etching stopper layer 13 is expanded, the etching stopper layer 13 is located on the red filter 12R, the green filter 12G, and the blue filter 12B.

[0048] The infrared light cutoff filter 14 is located on the light incident side relative to the etch barrier layer 13. The infrared light cutoff filter 14 has a through-hole 14H. Viewed from a viewpoint opposite to the plane extending from the infrared light cutoff filter 14, the infrared bandpass filter 12P is located within the area defined by the through-hole 14H. On the other hand, viewed from a viewpoint opposite to the plane extending from the infrared light cutoff filter 14, the infrared light cutoff filter 14 is located on the red filter 12R, the green filter 12G, the blue filter 12B, and the etch barrier layer 13.

[0049] The oxygen blocking layer 15 is located on the light incident side relative to the infrared light cutoff filter 14. The oxygen blocking layer 15 is a common layer for the red filter 12R, the green filter 12G, and the blue filter 12B. The oxygen blocking layer 15 suppresses the transmission of oxidation sources toward the infrared light cutoff filter 14. Oxidation sources include, for example, oxygen and water.

[0050] The oxygen barrier layer 15 preferably has an oxygen permeability of less than or equal to 5.0 cc / m³. 2 / day / atm. Oxygen permeability is based on the value in JIS K7126:2006. The oxygen permeability is specified as less than or equal to 5.0 cc / m³. 2 The oxygen barrier layer 15 can suppress the oxidation source from reaching the infrared light cutoff filter 14. Therefore, the infrared light cutoff filter 14 is not easily oxidized by the oxidation source. As a result, the light resistance of the infrared light cutoff filter 14 can be improved.

[0051] The microlens consists of a red microlens 16R, a green microlens 16G, a blue microlens 16B, and an infrared microlens 16P. The red microlens 16R is located on the incident side of light relative to the red filter 12R. The green microlens 16G is located on the incident side of light relative to the green filter 12G. The blue microlens 16B is located on the incident side of light relative to the blue filter 12B. The infrared microlens 16P is located on the incident side of light relative to the infrared bandpass filter 12P.

[0052] Each microlens 16R, 16G, 16B, and 16P has an incident surface 16S as its outer surface. Each microlens 16R, 16G, 16B, and 16P has a refractive index difference with the external air, i.e., the gas surrounding each microlens 16R, 16G, 16B, and 16P, to converge light incident on the incident surface 16S toward each photoelectric conversion element 11R, 11G, 11B, and 11P. Each microlens 16R, 16G, 16B, and 16P contains transparent resin.

[0053] The color filters 12R, 12G, 12B are thinner than the infrared light band pass filter 12P. The total of the thickness of the etching stopper layer 13 and the thickness of the infrared light cut filter 14 corresponds to the difference between the thickness of the color filters 12R, 12G, 12B and the thickness of the infrared light band pass filter 12P. The thickness of the infrared light band pass filter 12P is greater than the thickness of the color filters 12R, 12G, 12B. On the other hand, the step difference TP between the infrared light band pass filter 12P and the color filters 12R, 12G, 12B is filled by the etching stopper layer 13 and the infrared light cut filter 14. Therefore, it is easy to obtain the flatness of the lower layer of the color filters 16R, 16G, 16B and the infrared light micro lens 16P.

[0054] [Method for manufacturing solid-state imaging device]

[0055] Reference Figures 2 to 10 A method for manufacturing a solid-state imaging device including a filter for a solid-state imaging device will be described.

[0056] The method for manufacturing a filter for a solid-state imaging device includes the steps of forming a color filter, forming an etching stopper layer, forming an infrared light cut precursor layer, forming a resist pattern, and forming an infrared light cut filter. The color filter is formed on a semiconductor substrate by forming the color filter. The etching stopper layer is formed on the semiconductor substrate having the color filter by forming the etching stopper layer. The infrared light cut precursor layer having a different etching rate from the etching stopper layer in dry etching is formed on the etching stopper layer by forming the infrared light cut precursor layer. The resist pattern is formed so as to cover a portion of the infrared light cut precursor layer on the color filter by forming the resist pattern. The infrared light cut filter is formed by dry etching the infrared light cut precursor layer using the resist pattern.

[0057] Hereinafter, the method for manufacturing a filter for a solid-state imaging device and the method for manufacturing a solid-state imaging device will be described in more detail with reference to the drawings. Figures 2 to 10 A cross section when the solid-state imaging device is cut in a layer stacking direction of layers constituting the solid-state imaging device is schematically shown.

[0058] As Figure 2 shown in the method for manufacturing a filter for a solid-state imaging device, first, a semiconductor substrate 21 is prepared. A plurality of photoelectric conversion elements are two-dimensionally arranged on the semiconductor substrate 21 so that one photoelectric conversion element corresponds to one pixel. Further, in the Figures 2 to 10 illustration of two blue photoelectric conversion elements and three infrared light photoelectric conversion elements is omitted. In the Figures 2 to 10In the semiconductor substrate 21, photoelectric conversion elements for blue light and photoelectric conversion elements for infrared light are arranged alternately in one direction. The material forming the semiconductor substrate 21 can be, for example, Si and oxides such as SiO2, nitrides such as SiN, and mixtures thereof.

[0059] Furthermore, a blue filter 12B corresponding to the blue photoelectric conversion element of the semiconductor substrate 21 is formed on the semiconductor substrate 21. The blue filter 12B is formed by forming a coating containing a first photosensitive resin for forming the blue filter 12B and patterning the coating using photolithography. For example, the coating containing the first photosensitive resin is formed by applying a coating solution containing the first photosensitive resin and drying the coating. The blue filter 12B is formed by exposing and developing the coating containing the first photosensitive resin in the area corresponding to the blue filter 12B. In addition, a green filter 12G and a red filter 12R are formed on the semiconductor substrate 21 using the same method as the blue filter 12B.

[0060] like Figure 3 As shown, an etch barrier layer 23 is formed on a semiconductor substrate 21 having a blue filter 12B. When forming the etch barrier layer 23, a coating solution is first prepared using a silicon-containing resin. The silicon-containing resin can be, for example, a polysiloxane. The polysiloxane is formed by repeating siloxane bonds. The polysiloxane can be a silicone. Silicones are polysiloxanes and contain organic groups such as alkyl and aryl groups.

[0061] Next, a coating liquid is applied to the blue filter 12B and the exposed portions of the semiconductor substrate 21, and the coating is dried. Then, the dried coating is cured by heating. As a result, an etching barrier layer 23 is formed on the color filters for each color and on the portions of the semiconductor substrate 21 where the color filters for each color are not present.

[0062] like Figure 4 As shown, an infrared light cutoff precursor layer 24 is formed on the etch barrier layer 23. To form the infrared light cutoff precursor layer 24, firstly, a coating solution containing an infrared light-absorbing pigment, a transparent resin, and an organic solvent is applied to the etch barrier layer 23 and the coating is dried. Next, the dried coating is cured by heating. Thus, the infrared light cutoff precursor layer 24 is formed on the etch barrier layer 23.

[0063] The infrared-absorbing pigment used to form the infrared light-blocking precursor layer 24 can be, for example, anthraquinone pigments, anthocyanin pigments, phthalocyanine pigments, dithiol pigments, diimonium pigments, squarylium pigments, and chloronium pigments. The infrared-absorbing pigments are preferably anthocyanin-based pigments and phthalocyanine pigments from the above-mentioned sources.

[0064] The transparent resin used to form the infrared light blocking precursor layer 24 can be, for example, acrylic resin, polyamide resin, polyimide resin, polyurethane resin, polyester resin, polyether resin, polyolefin resin, polycarbonate resin, polystyrene resin, and norbornene resin. The transparent resin is preferably an acrylic resin among the above-mentioned resins.

[0065] like Figure 5 As shown, a resist pattern RP is formed that partially covers the blue filter 12B in the infrared cutoff precursor layer 24. When forming the resist pattern RP, firstly, a photoresist layer is formed on each color filter. A positive or negative resist can be used for forming the photoresist layer. Then, a portion of the photoresist layer is exposed using a photomask. In the case of a photoresist layer formed with a positive resist, only the portion of the photoresist layer covering the semiconductor substrate 21 is exposed. Conversely, in the case of a photoresist layer formed with a negative resist, only the portion of the photoresist layer covering each color cutoff filter is exposed. Next, the photoresist layer is developed. Thus, a resist pattern RP is formed that only covers the portion of the infrared cutoff precursor layer 24 formed on the color filter.

[0066] like Figure 6 As shown, an infrared light cutoff filter 14 is formed by dry etching an infrared light cutoff precursor layer 24 using a resist pattern RP. Additionally, a patterned etch stop layer 13 is formed. Dry etching can be, for example, plasma etching. Regarding dry etching, reactive gases and rare gases, i.e., gases composed of group 18 elements, can be used as the etching gas. Reactive gases can be, for example, oxygen, and rare gases can be, for example, argon. Regarding the dry etching of the infrared light cutoff precursor layer 24, a bias voltage can be applied to the object to be etched, including the infrared light cutoff precursor layer 24. Anisotropic etching using the resist pattern RP can be performed by applying the bias voltage. This removes portions of the infrared light cutoff precursor layer 24 and the etch stop layer 23 from their surfaces.

[0067] The etching rate of the etching stopper layer 23 is different from the etching rate of the infrared light cut-off precursor layer 24. The etching rate is the thickness of each layer etched per unit time. The etching rate of the etching stopper layer 23 can be lower than the etching rate of the infrared light cut-off precursor layer 24, or can be higher than the etching rate of the infrared light cut-off precursor layer 24. The etching rate of the etching stopper layer 23 is preferably lower than the etching rate of the infrared light cut-off precursor layer 24. Thus, compared to the case where the etching rate of the etching stopper layer 23 is higher than the etching rate of the infrared light cut-off precursor layer 24, the time required for etching the unnecessary portion of the etching stopper layer 23 can be extended. Thus, it is easy to adjust the time of etching in such a manner that the etchant is less likely to collide with the lower layer of the etching stopper layer 23.

[0068] In the manufacture of the optical filter for a solid-state imaging device, in order to form the infrared light band-pass filter 12P at the position where the infrared light cut-off precursor layer 24 is removed, it is required to perform over-etching in the etching of the infrared light cut-off precursor layer 24 and substantially remove the entire unnecessary portion of the infrared light cut-off precursor layer 24. In this regard, according to the structure having the etching stopper layer 23, even if a portion of the infrared light cut-off precursor layer 24 is removed by over-etching of the infrared light cut-off precursor layer 24, the etching stopper layer 23 is located under the infrared light cut-off precursor layer 24, and thus the collision of the etchant with the semiconductor substrate 21 can be suppressed. Thus, the degradation of the function of the solid-state imaging device 10 due to the change in the surface properties of the semiconductor substrate 21 can be suppressed.

[0069] Further, in terms of substantially completely removing the portion of the etching stopper layer 23 located on the surface of the semiconductor substrate 21, it is preferable that the etching rate of the etching stopper layer 23 be different from the etching rate of the lower layer of the etching stopper layer 23. In the present embodiment, it is preferable that the etching rate of the etching stopper layer 23 be different from the etching rate of the semiconductor substrate 21 which is the lower layer of the etching stopper layer 23.

[0070] As shown in FIG. 9, the resist pattern RP is peeled from the infrared light cut-off filter 14 using a peeling liquid LM. For the peeling liquid LM, a liquid capable of dissolving the material forming the resist pattern RP can be used. For the peeling liquid LM, for example, N-methylpyrrolidone or dimethyl sulfoxide can be used. Further, in the present embodiment, the dipping method is exemplified as the method of bringing the resist pattern RP into contact with the peeling liquid LM, but the spraying method and the spin coating method can also be used as the method of bringing the resist pattern RP into contact with the peeling liquid LM. Figure 7 Figure 7

[0071] As shown in FIG. 9, the resist pattern RP is peeled from the infrared light cut-off filter 14 using a peeling liquid LM. For the peeling liquid LM, a liquid capable of dissolving the material forming the resist pattern RP can be used. For the peeling liquid LM, for example, N-methylpyrrolidone or dimethyl sulfoxide can be used. Further, in the present embodiment, the dipping method is exemplified as the method of bringing the resist pattern RP into contact with the peeling liquid LM, but the spraying method and the spin coating method can also be used as the method of bringing the resist pattern RP into contact with the peeling liquid LM. Figure 8 ​​As shown, an infrared bandpass filter 12P is formed on the portion of the semiconductor substrate 21 where the infrared light photoelectric conversion element is located. The infrared bandpass filter 12P is formed by forming a coating film containing a colored photosensitive resin and patterning the coating film using photolithography. For example, the coating film containing the colored photosensitive resin is formed by applying a coating liquid containing an infrared light photosensitive resin and drying the coating film.

[0072] Infrared photosensitive resins contain black pigments or black dyes, as well as photosensitive resins. Black pigments are black due to the presence of a single black pigment, or a mixture of two or more black pigments. Examples of black dyes include azo dyes, anthraquinone dyes, azine dyes, quinolone dyes, cyclic ketone dyes, dinaphthalene-based dyes, and hypomethane dyes. Transparent resins include, for example, acrylic resins, polyamide resins, polyimide resins, polyurethane resins, polyester resins, polyether resins, polyolefin resins, polycarbonate resins, polystyrene resins, and norbornene resins.

[0073] The material forming the infrared bandpass filter 12P may contain particles of inorganic oxides used to adjust the refractive index. Examples of inorganic oxides include aluminum oxide, silicon oxide, zirconium oxide, and titanium oxide. In addition to its function of suppressing visible light transmission as an infrared bandpass filter 12P, the infrared bandpass filter 12P may contain additives such as light stabilizers, antioxidants, heat stabilizers, and anti-static agents to provide other functions.

[0074] An infrared bandpass filter 12P is formed by exposing and developing a coating containing a photosensitive resin for infrared light in an area corresponding to the infrared bandpass filter 12P. Preferably, the infrared bandpass filter 12P has a thickness equal to the thickness of the laminate formed by the blue filter 12B, the etch barrier layer 13, and the infrared cutoff filter 14.

[0075] like Figure 9 As shown, an oxygen barrier layer 15 is formed, covering the surface of the infrared cut-off filter 14 and the surface of the infrared bandpass filter 12P, as viewed from a plane extending from the semiconductor substrate 21. The oxygen barrier layer 15 is formed by vapor phase deposition methods such as sputtering, CVD, and ion plating, or liquid phase deposition methods such as coating. For example, an oxygen barrier layer 15 made of silicon oxide is formed by sputtering based on a target material made of silicon oxide. For example, an oxygen barrier layer 15 made of silicon oxide is formed by CVD based on silane and oxygen. For example, an oxygen barrier layer 15 made of silicon oxide is formed by coating, modifying, and drying a coating solution containing polysilazane.

[0076] like Figure 10 As shown, a plurality of microlenses 16 are formed on the oxygen barrier layer 15. This enables the formation of a solid-state imaging element with a filter for a solid-state imaging element. Viewed from a viewpoint opposite to the plane extending from the oxygen barrier layer 15, the plurality of microlenses 16 are formed at positions overlapping with the color filter and the infrared bandpass filter 12P. Each microlens 16 is formed, for example, using an etching method. In the etching method, firstly, a transparent resin layer for forming the microlenses 16 is formed. Next, a resist pattern having a plurality of hemispherical arrangements is formed on the transparent resin layer. Furthermore, the plurality of microlenses 16 are formed by dry etching the transparent resin layer with the resist pattern and transferring the shape of the resist pattern onto the transparent resin layer.

[0077] Thus, multiple previously referenced elements can be formed relative to one semiconductor substrate 21. Figure 1 The solid-state imaging element 10 has been described.

[0078] As explained above, the manufacturing method of the filter for a solid-state imaging element and the manufacturing method of the solid-state imaging element according to the first embodiment can achieve the following effects.

[0079] (1) Even if a portion of the infrared light cutoff precursor layer 24 is removed by over-etching, the etch barrier layer 23 is located below the infrared light cutoff precursor layer 24, thus suppressing the collision of the etchant with the layer below the etch barrier layer 23. As a result, the functional degradation of the solid-state imaging element 10 caused by changes in the surface properties of the layer below the infrared light cutoff precursor layer 24, which is the object of etching, can be suppressed.

[0080] (2) The oxygen barrier layer 15 can suppress the oxidation source from reaching the infrared light cutoff filter 14, so the infrared light bandpass filter 12P is not easily oxidized.

[0081] [Modification of the first embodiment]

[0082] Furthermore, the first embodiment described above can be modified as follows.

[0083] [Oxygen barrier]

[0084] The oxygen barrier layer 15 is not limited to the infrared light cutoff filter 14 and the infrared light bandpass filter 12P between each microlens 16, but can also be located on the outer surface of each microlens 16.

[0085] In this case, such as Figure 11As shown, a plurality of microlenses 26 are formed on the surface including the surface of the infrared light cut filter 14 and the surface of the infrared light band pass filter 12P. Each of the microlenses 26 covers any one of the color filters for each color and the infrared light band pass filter 12P.

[0086] As shown, an oxygen barrier layer 25 is formed to cover the surfaces of the plurality of microlenses 26. The oxygen barrier layer 25 can also have a function as an antireflection layer. Figure 12

[0087] • The filter 10F for a solid-state imaging device can also not have the oxygen barrier layer 15. Even in this case, by forming the infrared light cut precursor layer 24 on the etching stop layer 23 that covers the surface of the semiconductor substrate 21, the effect based on the above (1) can be obtained.

[0088] • The layer structure of the oxygen barrier layer 25 can be a single layer structure composed of a single compound, a stacked layer structure of layers composed of a single compound, or a stacked layer structure of layers composed of different compounds.

[0089] • The surface of the infrared light cut filter 14 and the surface of the infrared light band pass filter 12P can have a step difference in the thickness direction of the semiconductor substrate 21. In this case, the oxygen barrier layer 15 can function as a planarization layer that fills the step difference formed by the surface of the infrared light cut filter 14 and the surface of the infrared light band pass filter 12P. Further, the oxygen barrier layer 15 has a thickness capable of filling the step difference between the surface of the infrared light cut filter 14 and the infrared light band pass filter 12P and can function as a planarization layer.

[0090] [Infrared light filter]

[0091] • The thickness of the infrared light band pass filter 12P can be equal to the thickness of the filter for each color. In this case, with respect to the solid-state imaging device, the oxygen barrier layer 15 can fill the step difference between the surface of the infrared light band pass filter 12P and the surface of the infrared light cut filter 14. Alternatively, the solid-state imaging device can have a planarization layer that fills the step difference between the surface of the infrared light band pass filter 12P and the surface of the infrared light cut filter 14, which is different from the oxygen barrier layer 15.

[0092] [Etching stop layer]

[0093] • In the etching stop layer 23, a portion formed on the surface of the semiconductor substrate 21 can not be completely removed. Even in this case, by forming the etching stop layer 23 of a transparent resin, the light incident to the solid-state imaging device can be made to be incident to the photoelectric conversion element via the etching stop layer 23.

[0094] ​[2nd Embodiment]

[0095] Reference Figures 13 to 17 A 2nd embodiment of a method for manufacturing a filter for a solid-state imaging device and a method for manufacturing a solid-state imaging device will be described. In the 2nd embodiment, an infrared light filter is formed in a portion of the semiconductor substrate where no color filter is formed before the etching stopper layer is formed. Thus, the above-described difference will be described in detail below, and detailed description of the processes common to the 1st embodiment will be omitted in the 2nd embodiment. Further, the same reference numerals as those used in the 1st embodiment will be assigned to the structures common to the 1st embodiment in the 2nd embodiment.

[0096] As Figure 13 shown, in the semiconductor substrate 21, the blue filter 12B is formed at a position corresponding to the blue photoelectric conversion element included in the semiconductor substrate 21, and the infrared light band-pass filter 12P is formed at a position corresponding to the infrared light photoelectric conversion element. At this time, each filter is formed so that the thickness of the infrared light band-pass filter 12P is greater than the thickness of the blue filter 12B.

[0097] Further, each color filter including the blue filter 12B can be formed before the infrared light band-pass filter 12P, or the infrared light band-pass filter 12P can be formed before each color filter. In addition, each color filter and the infrared light band-pass filter 12P are formed by the same method as each color filter and the infrared light band-pass filter 12P of the above-described 1st embodiment, respectively.

[0098] As Figure 14 shown, the etching stopper layer 33 is formed on the semiconductor substrate 21 having the blue filter 12B and the infrared light band-pass filter 12P. Thus, the etching stopper layer 33 is formed on each color filter and the infrared light band-pass filter 12P. The etching stopper layer 33 is formed by the same method as the etching stopper layer 23 of the above-described 1st embodiment.

[0099] As Figure 15 shown, the infrared light cut-off precursor layer 34 is formed on the etching stopper layer 33. Thus, the infrared light cut-off precursor layer 34 is formed in both of the portions of the etching stopper layer 33 located on the blue filter 12B and the infrared light band-pass filter 12P. The infrared light cut-off precursor layer 34 is formed by the same method as the infrared light cut-off precursor layer 24 of the above-described 1st embodiment.

[0100] As Figure 16As shown, in the infrared light-cut-off precursor layer 34, a resist pattern RP that covers a portion of each color filter is formed. In forming the resist pattern RP, first, a photoresist layer is formed on the infrared light-cut-off precursor layer 34. As a material for forming the photoresist layer, a positive resist can be used as well as a negative resist, as in the first embodiment. Further, a portion of the photoresist layer is exposed using a photomask. At this time, in the case where the photoresist layer is formed of a positive resist, only a portion of the infrared light-cut-off precursor layer 34 that covers the infrared light-pass filter 12P is exposed. In contrast, in the case where the photoresist layer is formed of a negative resist, only a portion of the photoresist layer that covers each color filter is exposed. Next, the photoresist layer is developed. Thus, in the infrared light-cut-off precursor layer 34, a resist pattern RP that covers only a portion of each color filter formed on the color filter is formed.

[0101] As shown, the infrared light-cut-off filter 14 is formed by dry etching the infrared light-cut-off precursor layer 34 using the resist pattern RP. In addition, the etching stopper layer 13 that has been patterned is formed. By etching using the resist pattern RP as an etching mask, a portion of the infrared light-cut-off precursor layer 34 and the etching stopper layer 33 that is located on the infrared light-pass filter 12P is removed from each layer. Figure 17 In the present embodiment, a portion of the infrared light-cut-off precursor layer 34 is located on the infrared light-pass filter 12P, and thus in order to sufficiently exhibit the function of the infrared light-pass filter 12P, it is necessary to substantially completely remove the portion of the infrared light-cut-off precursor layer 34 that is located on the infrared light-pass filter 12P. In this regard, the etching stopper layer 33 is located between the infrared light-pass filter 12P and the infrared light-cut-off precursor layer 34. Thus, even if the infrared light-cut-off precursor layer 34 is over-etched in order to remove the infrared light-cut-off precursor layer 34, the etching stopper layer 33 can suppress a change in surface properties of the infrared light-pass filter 12P, and as a result, can suppress a decrease in the function of the solid-state imaging device due to a change in surface properties of the infrared light-pass filter 12P.

[0102] Further, in the etching stopper layer 33, in terms of substantially completely removing the portion located on the infrared light-pass filter 12P, it is preferable that the etching rate of the etching stopper layer 33 and the etching rate of the infrared light-pass filter 12P be different from each other.

[0103] After the infrared light-cut-off filter 14 is formed, the solid-state imaging device is manufactured via the same processes as those described above with reference to the processes described in the first embodiment.

[0104] Figures 7 to 10 After the infrared light-cut-off filter 14 is formed, the solid-state imaging device is manufactured via the same processes as those described above with reference to the processes described in the first embodiment.

[0105] ​As explained above, the manufacturing method of the optical filter for a solid-state imaging device and the manufacturing method of the solid-state imaging device according to the second embodiment can achieve the same effects as those of (1) and (2) above.

[0106] [Alterations of the Second Embodiment]

[0107] Further, the second embodiment above can be altered and implemented in the following manner.

[0108] • The structure disclosed in the second embodiment can be implemented in combination with the structures disclosed in each of the alterations of the oxygen barrier layer and the alterations of the etching stopper layer of the first embodiment.

[0109] [Third Embodiment]

[0110] Reference Figure 18 and Figure 19 will be explained. In the third embodiment, a partition wall that covers a color filter and an infrared light cut filter is formed, unlike the first embodiment. Therefore, the following will explain the difference in detail, and the detailed explanation of the processes common to the first embodiment will be omitted in the third embodiment. Further, the same reference numerals as those used in the first embodiment will be assigned to the structures common to the first embodiment in the third embodiment.

[0111] In the manufacturing method of the solid-state imaging device of the present embodiment, first, the color filter 12B, the etching stopper layer 23, the infrared light cut precursor layer 24, and the resist pattern RP are formed on the semiconductor substrate 21 by the processes explained with reference to Figures 2 to 5 in the first embodiment above.

[0112] Next, as shown in Figure 18 , the etching stopper layer 23 and the infrared light cut precursor layer 24 formed on the portions where the color filter 12B is not present are removed by dry etching in the surface of the semiconductor substrate 21. As in the first embodiment, plasma is generated from the etching gas in the dry etching of the infrared light cut precursor layer 24. Thereby, the etchant E in the plasma collides with the infrared light cut precursor layer 24 first, and then collides with the etching stopper layer 23 that is the lower layer of the infrared light cut precursor layer 24. Thereby, at least the etching stopper layer 23 is sputtered by the etchant E to release particles from the etching stopper layer 23. At least a part of the particles released from the etching stopper layer 23 adhere to the side surface of the color filter 12B, the side surface of the etching stopper layer 23 on the color filter 12B, and the side surface of the portion of the infrared light cut precursor layer 24 on the color filter 12B.

[0113] Therefore, as Figure 19 As shown, a partition wall 47 is formed that covers the side surface of the blue filter 12B, the side surface of the etch barrier layer 13, and the side surface of the infrared cutoff filter 14. The partition wall 47 reflects incident light at the interface with the layer adjacent to it. Specifically, the partition wall 47 reflects light incident on it at the interface between the side surface of the blue filter 12B and a portion of the partition wall 47 using the difference in refractive index. Similarly, the partition wall 47 reflects light incident on it at the interface between the side surface of the etch barrier layer 13 and a portion of the partition wall 47 using the difference in refractive index. Finally, the partition wall 47 reflects light incident on it at the interface between the side surface of the infrared cutoff filter 14 and a portion of the partition wall 47 using the difference in refractive index.

[0114] Therefore, the partition wall 47 suppresses the transmission of light incident obliquely upward relative to the infrared cutoff filter 14 to the outside of the infrared cutoff filter 14. Thus, the reduction in the amount of light incident on the blue photoelectric conversion element located below the infrared cutoff filter 14 can be suppressed. Furthermore, the partition wall 47 suppresses the transmission of light incident obliquely upward relative to the blue filter 12B to the outside of the blue filter 12B. Therefore, the reduction in the amount of light incident on the blue photoelectric conversion element located below the blue filter 12B can be suppressed. Moreover, the reception of light incident on the blue filter 12B by the photoelectric conversion element corresponding to other filters can be suppressed.

[0115] The partition wall 47 may contain at least one of the following: the material forming the infrared light cutoff precursor layer 24, the material forming the etch barrier layer 23, the reaction product of the material forming the infrared light cutoff precursor layer 24 and the etchant E, and the reaction product of the material forming the etch barrier layer 23 and the etchant E.

[0116] In the manufacturing method of the solid-state imaging element of this embodiment, after the partition wall 47 is formed, the image is transmitted via the method previously referred to in the first embodiment. Figures 7 to 10 Solid-state imaging elements are manufactured using the processes described above. Furthermore, referencing previous... Figure 7 During the described process, sometimes the infrared light-absorbing pigment contained in the infrared light cut-off filter 14 dissolves relative to the stripping liquid LM due to contact between the stripping liquid LM and the infrared light cut-off filter 14. Regarding this, in the solid-state imaging element manufacturing method of this embodiment, when the resist pattern RP is stripped using the stripping liquid LM, a portion of the side of the infrared light cut-off filter 14 is covered by the partition wall 47, thus reducing the area of ​​the infrared light cut-off filter 14 in contact with the stripping liquid LM. Therefore, the dissolution of infrared light-absorbing pigment contained in the infrared light cut-off filter 14 relative to the stripping liquid LM can be suppressed.

[0117] Further, in the case where the etching stopper layer 23 is formed of polysiloxane, it is possible to make it less likely to cause elution of the infrared light absorbing colorant due to the partition wall 47 containing at least one of polysiloxane and a reaction product of polysiloxane and the etchant E.

[0118] The thickness of the partition wall 47 can be changed by adjusting various conditions of etching of the infrared light cut-off precursor layer 24 and the etching stopper layer 23. For example, the thickness of the partition wall 47 can be adjusted according to the magnitude of the bias voltage applied to the etching target including the infrared light cut-off precursor layer 24 and the etching stopper layer 23. There is a tendency that the greater the bias voltage applied to the etching target, the greater the thickness of the partition wall 47. The greater the bias voltage applied to the etching target, the higher the energy of the etchant colliding with the etching target, and thus it is easy to release the particles for forming the partition wall 47 from the infrared light cut-off precursor layer 24 and the etching stopper layer 23.

[0119] In addition, for example, the thickness of the partition wall 47 can be adjusted according to the magnitude of the pressure of the atmosphere in which dry etching is performed. By changing the magnitude of the pressure, the amount of the etchant that can collide with the etching target is changed. In addition, by changing the magnitude of the pressure, the state in which the particles released from the infrared light cut-off precursor layer 24 and the etching stopper layer 23 collide with the particles present in the atmosphere is changed. The pressure of the atmosphere in which dry etching is performed can be, for example, greater than or equal to 0.1 Pa and less than or equal to 3.0 Pa. Thus, it is easy to form the partition wall 47 on the side surface of the infrared light cut-off filter 14 and the side surface of each color filter.

[0120] In addition, the thickness of the partition wall 47 can be adjusted according to the thickness of the infrared light cut-off precursor layer 24 and the thickness of the etching stopper layer 23. There is a tendency that the greater the thickness of the infrared light cut-off precursor layer 24 and the thickness of the etching stopper layer 23, respectively, the greater the thickness of the partition wall 47.

[0121] As described above, according to the method for manufacturing the filter for a solid-state imaging device and the method for manufacturing the solid-state imaging device according to the third embodiment, in addition to the effects of (1) and (2) described above, the following effects can be obtained.

[0122] (3) The light incident to the color filter is suppressed from being transmitted from the side surface of the color filter to the outside of the color filter by the partition wall 47. Thus, it is possible to suppress a decrease in the amount of light incident to the photoelectric conversion element corresponding to the color filter.

[0123] (4) The partition wall 47 also suppresses transmission of light incident to the infrared light cut filter 14 from the side surface of the infrared light cut filter 14 to the outside of the infrared light cut filter 14. Therefore, it is possible to further suppress reduction in the amount of light of light incident to the photoelectric conversion element into which light passing through the color filter as the lower layer of the infrared light cut filter 14 is incident.

[0124] (5) The partition wall 47 containing at least one of polysiloxane and a reaction product of polysiloxane and an etchant suppresses contact of the peeling liquid with the infrared light cut filter 14. Therefore, the infrared light absorbing pigment contained in the infrared light cut filter 14 is suppressed from being eluted with respect to the peeling liquid by the partition wall 47.

[0125] [Modification of the 3rd Embodiment]

[0126] Further, the above 3rd embodiment can be modified and implemented in the following manner.

[0127] [Partition Wall]

[0128] The partition wall 47 can cover the side surface of the color filter, or can not cover the side surface of the infrared light cut filter 14. In this case, the effect based on the above (3) can also be obtained.

[0129] [Other Modifications]

[0130] The structure disclosed in the 3rd embodiment can be implemented in combination with the structures disclosed in each modification of the oxygen partition layer and the modification of the etching stopper layer of the 1st embodiment.

[0131] [4th Embodiment]

[0132] Reference Figures 20 to 26 The 4th embodiment of the manufacturing method of the filter for a solid-state imaging device and the manufacturing method of the solid-state imaging device will be described. In the 4th embodiment, an infrared light filter is formed in a portion where the color filter is not present in the semiconductor substrate before the etching stopper layer is formed, and the partition wall covering the side surface of the infrared light cut filter is different from the 1st embodiment. Therefore, the following will describe the difference in detail, and the detailed description of the process common to the 1st embodiment will be omitted in the 4th embodiment. Further, the structure common to the 1st embodiment in the 4th embodiment is denoted by the same reference numerals as those used in the 1st embodiment.

[0133] As Figure 20As shown in FIG. 1, the blue filter 12B is formed in a portion of the semiconductor substrate 21 where the blue photoelectric conversion element is present. Also, the infrared light band-pass filter 12P is formed in a portion of the semiconductor substrate 21 where the infrared light photoelectric conversion element is present. At this time, in the present embodiment, the infrared light band-pass filter 12P and the blue filter 12B are formed in such a manner that the thickness of the infrared light band-pass filter 12P is equal to the thickness of the blue filter 12B. The blue filter 12B and the infrared light band-pass filter 12P are formed by the same method as the blue filter 12B and the infrared light band-pass filter 12P of the first embodiment described above.

[0134] As shown in FIG. 1, the blue filter 12B is formed in a portion of the semiconductor substrate 21 where the blue photoelectric conversion element is present. Also, the infrared light band-pass filter 12P is formed in a portion of the semiconductor substrate 21 where the infrared light photoelectric conversion element is present. At this time, in the present embodiment, the infrared light band-pass filter 12P and the blue filter 12B are formed in such a manner that the thickness of the infrared light band-pass filter 12P is equal to the thickness of the blue filter 12B. The blue filter 12B and the infrared light band-pass filter 12P are formed by the same method as the blue filter 12B and the infrared light band-pass filter 12P of the first embodiment described above. Figure 21 As shown in FIG. 1, the blue filter 12B is formed in a portion of the semiconductor substrate 21 where the blue photoelectric conversion element is present. Also, the infrared light band-pass filter 12P is formed in a portion of the semiconductor substrate 21 where the infrared light photoelectric conversion element is present. At this time, in the present embodiment, the infrared light band-pass filter 12P and the blue filter 12B are formed in such a manner that the thickness of the infrared light band-pass filter 12P is equal to the thickness of the blue filter 12B. The blue filter 12B and the infrared light band-pass filter 12P are formed by the same method as the blue filter 12B and the infrared light band-pass filter 12P of the first embodiment described above.

[0135] As shown in FIG. 1, the blue filter 12B is formed in a portion of the semiconductor substrate 21 where the blue photoelectric conversion element is present. Also, the infrared light band-pass filter 12P is formed in a portion of the semiconductor substrate 21 where the infrared light photoelectric conversion element is present. At this time, in the present embodiment, the infrared light band-pass filter 12P and the blue filter 12B are formed in such a manner that the thickness of the infrared light band-pass filter 12P is equal to the thickness of the blue filter 12B. The blue filter 12B and the infrared light band-pass filter 12P are formed by the same method as the blue filter 12B and the infrared light band-pass filter 12P of the first embodiment described above. Figure 22 As shown in FIG. 1, the blue filter 12B is formed in a portion of the semiconductor substrate 21 where the blue photoelectric conversion element is present. Also, the infrared light band-pass filter 12P is formed in a portion of the semiconductor substrate 21 where the infrared light photoelectric conversion element is present. At this time, in the present embodiment, the infrared light band-pass filter 12P and the blue filter 12B are formed in such a manner that the thickness of the infrared light band-pass filter 12P is equal to the thickness of the blue filter 12B. The blue filter 12B and the infrared light band-pass filter 12P are formed by the same method as the blue filter 12B and the infrared light band-pass filter 12P of the first embodiment described above.

[0136] As shown in FIG. 1, the blue filter 12B is formed in a portion of the semiconductor substrate 21 where the blue photoelectric conversion element is present. Also, the infrared light band-pass filter 12P is formed in a portion of the semiconductor substrate 21 where the infrared light photoelectric conversion element is present. At this time, in the present embodiment, the infrared light band-pass filter 12P and the blue filter 12B are formed in such a manner that the thickness of the infrared light band-pass filter 12P is equal to the thickness of the blue filter 12B. The blue filter 12B and the infrared light band-pass filter 12P are formed by the same method as the blue filter 12B and the infrared light band-pass filter 12P of the first embodiment described above. Figure 23 As shown in FIG. 1, the blue filter 12B is formed in a portion of the semiconductor substrate 21 where the blue photoelectric conversion element is present. Also, the infrared light band-pass filter 12P is formed in a portion of the semiconductor substrate 21 where the infrared light photoelectric conversion element is present. At this time, in the present embodiment, the infrared light band-pass filter 12P and the blue filter 12B are formed in such a manner that the thickness of the infrared light band-pass filter 12P is equal to the thickness of the blue filter 12B. The blue filter 12B and the infrared light band-pass filter 12P are formed by the same method as the blue filter 12B and the infrared light band-pass filter 12P of the first embodiment described above.

[0137] As shown in FIG. 1, the blue filter 12B is formed in a portion of the semiconductor substrate 21 where the blue photoelectric conversion element is present. Also, the infrared light band-pass filter 12P is formed in a portion of the semiconductor substrate 21 where the infrared light photoelectric conversion element is present. At this time, in the present embodiment, the infrared light band-pass filter 12P and the blue filter 12B are formed in such a manner that the thickness of the infrared light band-pass filter 12P is equal to the thickness of the blue filter 12B. The blue filter 12B and the infrared light band-pass filter 12P are formed by the same method as the blue filter 12B and the infrared light band-pass filter 12P of the first embodiment described above. Figure 24As shown, the infrared light-cut filter 14 is formed by dry etching the infrared light-cut precursor layer 54 using the resist pattern RP. By dry etching using the resist pattern RP, the second portion 54b of the infrared light-cut precursor layer 54 and the portion of the etching stopper layer 53 covered by the second portion 54b are removed from the infrared light-pass filter 12P. As in the third embodiment described above, in the dry etching, the etchant E contained in the plasma collides with the etching stopper layer 53 and the infrared light-cut precursor layer 54. Thereby, the second portion 54b and the portion of the etching stopper layer 53 covered by the second portion 54b are removed.

[0138] At this time, as in the third embodiment, at least the etching stopper layer 53 is sputtered using the etchant E to release particles from the etching stopper layer 53. At least a portion of the particles released from the etching stopper layer 53 adhere to the side surface of the first portion 54a of the infrared light-cut precursor layer 54.

[0139] Thereby, as shown in FIG. 6, the partition wall 57 covering the side surface of the infrared light-cut filter 14 is formed. The partition wall 57 reflects incident light at the interface with the layer adjacent to the partition wall 57. That is, the partition wall 57 reflects light incident to the partition wall 57 using the difference in refractive index at the interface of the side surface of the infrared light-cut filter 14 and the portion of the partition wall 57. Thereby, transmission of light incident obliquely above the infrared light-cut filter 14 to the outside of the infrared light-cut filter 14 is suppressed by the partition wall 57. Therefore, reduction in the amount of light incident to the blue photoelectric conversion element located in the lower layer of the infrared light-cut filter 14 can be suppressed. Figure 25

[0140] As in the third embodiment, the partition wall 57 can contain at least one of the formation material of the infrared light-cut precursor layer 54, the formation material of the etching stopper layer 53, the reaction product of the formation material of the infrared light-cut precursor layer 54 and the etchant E, and the reaction product of the formation material of the etching stopper layer 53 and the etchant E. According to the partition wall 57 of the present embodiment, as with the partition wall 47 of the third embodiment, the infrared light-absorbing pigment contained in the infrared light-cut filter 14 can be suppressed from dissolving out into the peeling liquid LM.

[0141] As shown in FIG. 6, the partition wall 57 is formed on the side surface of the infrared light-cut filter 14. The partition wall 57 is formed by dry etching the infrared light-cut precursor layer 54 using the resist pattern RP. The partition wall 57 is formed by dry etching the infrared light-cut precursor layer 54 using the resist pattern RP. The partition wall 57 is formed by dry etching the infrared light-cut precursor layer 54 using the resist pattern RP. The partition wall 57 is formed by dry etching the infrared light-cut precursor layer 54 using the resist pattern RP. Figure 26 ​As shown, after the resist pattern RP is peeled off from the infrared light cut filter 14, the surface of the infrared light pass filter 12P, the surface of the infrared light cut filter 14, and the planarization layer 58 covered by the partition wall 57 are observed from a viewpoint opposite to the plane expanding from the semiconductor substrate 21. The planarization layer 58 has a thickness capable of filling in the step difference between the surface of the infrared light pass filter 12P and the surface of the infrared light cut filter 14. The planarization layer 58 is formed, for example, by formation of a coating film containing a transparent resin, and reflow of the coating film based on heat treatment.

[0142] Next, the solid-state imaging device can be obtained via the process described above with reference to Figure 9 and Figure 10 the first embodiment.

[0143] As described above, according to the method for manufacturing a filter for a solid-state imaging device and the method for manufacturing a solid-state imaging device of the fourth embodiment, in addition to the effects of (1), (2), (4), and (5) described above, the effects described below can be obtained.

[0144] (6) The surface of the first portion 54a is located at the same height as the surface of the second portion 54b in the thickness direction of the infrared light cut precursor layer 54, so it is easy to form the partition wall 57 on the entire side surface of the infrared light cut filter 14. Thus, it is possible to improve the reliability of the light that is inhibited from being incident on the infrared light cut filter 14 by the partition wall 57 from being incident on the infrared light pass filter 12P through the infrared light cut filter 14.

[0145] (7) By forming the infrared light pass filter 12P having a thickness smaller than or equal to the thickness of the color filter, it is possible to form the partition wall 57 on the entire side surface of the infrared light cut filter 14.

[0146] [Alterations of the Fourth Embodiment]

[0147] Furthermore, the fourth embodiment described above can be altered and implemented in the following manner.

[0148] [Infrared Light Filter]

[0149] The thickness of the infrared light pass filter 12P can be smaller than the thickness of each color color filter. Thus, in the infrared light cut precursor layer 54, the surface of the first portion 54a is higher than the surface of the second portion 54b. As a result, it is possible to improve the reliability of forming the partition wall 57 on the entire side surface of the infrared light cut filter 14.

[0150] • The thickness of the infrared light band-pass filter 12P can be greater than the thickness of each color filter. In this case, as long as the total thickness obtained by adding the thickness of each color filter, the thickness of the etching stopper layer 53, and the thickness of the infrared light cut-off precursor layer 54 is greater than the thickness of the infrared light band-pass filter 12P. Thus, in the side surface of the infrared light cut-off filter 14, the partition wall 57 can be formed in a portion that is more convex than the infrared light band-pass filter 12P.

[0151] [Other Modified Examples]

[0152] • The structure disclosed in the fourth embodiment can be combined with the structures disclosed in each of the modified examples of the oxygen barrier layer and the modified examples of the etching stopper layer of the first embodiment.

[0153] [Embodiment]

[0154] Next, a manufacturing example of a solid-state imaging device corresponding to the fourth embodiment will be described. In the manufacturing example described below, a manufacturing example of a solid-state imaging device in which the thickness of the infrared light filter is greater than the thickness of each color filter will be described.

[0155] A green color resist layer was formed by spin coating a green color resist containing a green pigment, a photosensitive curable resin, and a thermally curable resin at a rotation speed of 1000 rpm on a semiconductor substrate on which a plurality of photoelectric conversion elements were arranged two-dimensionally. As the green pigment, C.I. PG58 was used. As for the green color resist, the concentration of the green pigment was set to 70% by mass. Next, after selectively exposing the green color resist layer using a green color mask, the exposed green color resist layer was developed to form a green color filter pattern. Furthermore, the green color filter pattern was cured by heating it using a hot plate at a temperature of 230°C for 6 minutes. Thus, a green color filter having a thickness of 600 nm was formed.

[0156] Next, a blue resist layer containing a pigment, a photosensitive curable resin, and a thermally curable resin was formed by spin coating at a rotation speed of 1000 rpm on the green filter and on the portions of the semiconductor substrate not covered by the green filter. For the pigment, C.I. PB 156 and C.I. PV23 of the color index were used. The concentration of the pigment was set to 50 mass% for the blue resist. Next, after the blue resist layer was selectively exposed by photolithography using a blue mask, the exposed blue resist layer was developed to form a blue filter pattern. Further, the blue filter pattern was cured by heating at a temperature of 230°C for 6 minutes using a hot plate. Thus, a blue color filter having a thickness of 600 nm was formed. At this time, the blue filter was formed on the surface of the semiconductor substrate at a position different from the positions where the green filter was formed.

[0157] Further, a red resist layer containing a pigment, a photosensitive curable resin, and a thermally curable resin was formed by spin coating at a rotation speed of 1000 rpm on the green filter, on the blue filter, and on the portions of the semiconductor substrate not covered by the filters. For the pigment, C.I. PR 254 and C.I. PY 139 of the color index were used. The concentration of the pigment was set to 60 mass% for the red resist. Next, after the red resist layer was selectively exposed using a red mask, the exposed red resist layer was developed to form a red filter pattern. Further, the red filter pattern was cured by heating at a temperature of 230°C for 6 minutes using a hot plate. Thus, a red color filter having a thickness of 600 nm was formed. At this time, the red filter was formed on the surface of the semiconductor substrate at a position different from the positions where the blue filter and the green filter were formed.

[0158] Next, an infrared light band-pass resist having photosensitivity containing a cyan pigment, a violet pigment, and a yellow pigment was applied on the color filters of the respective colors and on the portions of the semiconductor substrate not covered by the color filters. Thus, an infrared light band-pass resist layer was formed. For the cyan pigment, C.I. PB 15:6 of the color index was used, for the violet pigment, C.I. PV23 of the color index was used, and for the yellow pigment, C.I. PY 139 of the color index was used. The concentration of the pigment was set to 78 mass% for the infrared light band-pass resist.

[0159] Next, after selectively exposing the infrared light bandpass resist layer using an infrared light bandpass mask, the exposed infrared light bandpass resist layer is developed to form an infrared light filter pattern. Also, the infrared light filter pattern is heated using a hot plate at a temperature of 230°C for 6 minutes to cure it. Thus, an infrared light filter having a thickness of 1500 nm is formed. At this time, the infrared light filter is formed at a position on the surface of the semiconductor substrate different from the positions at which the above-described color filters are formed. Furthermore, in the infrared light filter, the maximum value of the transmittance with respect to light having a wavelength of 400 nm or more and 650 nm or less is 4.8%, and the maximum value of the transmittance with respect to light having a wavelength of 650 nm or more and 730 nm or less is 8.6%. In addition, in the infrared light filter, the minimum value of the transmittance with respect to light having a wavelength of 800 nm or more and 1000 nm or less is 92.1%.

[0160] On the color filters and the infrared light filter, a siloxane-containing dispersion liquid is spin-coated at a rotation speed of 2000 rpm to form a coating film. Also, the coating film is heated using a hot plate at a temperature of 200°C for 20 minutes to cure it. Thus, an etching stopper layer having a thickness of 50 nm is formed on the color filters and the infrared light filter. With respect to the etching stopper layer, the transmittance with respect to visible light is 91%, and the refractive index is 1.40.

[0161] Next, on the etching stopper layer, a coating liquid containing an infrared light absorbing colorant and a thermosetting resin is spin-coated at a rotation speed of 1000 rpm to form a coating film. Also, the coating film is heated using a hot plate at a temperature of 200°C for 20 minutes to cure it. Thus, an infrared light cut-off precursor layer having a thickness of 1600 nm is formed on the etching stopper layer. With respect to the infrared light cut-off precursor layer, the transmittance with respect to light having a wavelength of around 940 nm is 8%.

[0162] On the infrared light cut-off precursor layer, a coating solution containing a positive resist (OFPR-800, manufactured by Tokyo Ohka Kogyo Co., Ltd.) was spin-coated at a rotation speed of 1000 rpm using a spin coater, thereby forming a resist layer. Then, the resist layer was subjected to pre-baking at a temperature of 90°C for 1 minute. Thus, a resist layer having a thickness of 1.5 μm was formed. Next, the resist layer was selectively exposed using a photomask. For the exposure of the resist layer, i-rays were used. Further, the exposed resist layer was developed using 2.38 mass% TMAH (tetramethylammonium hydroxide). Thus, a resist pattern having an opening exposing a portion covered with the infrared light filter in the infrared light cut-off precursor layer was formed from a viewpoint opposite to the plane from which the infrared light cut-off precursor layer extended. At this time, the opening was formed in a square shape with a length of 1.1 μm and a width of 1.1 μm at the edge of the opening.

[0163] Next, the infrared light cut-off precursor layer was dry-etched using the resist pattern. At this time, an ICP type dry etching device was used for the dry etching device. A mixed gas containing argon and oxygen was used for the etching gas, and the etching target was subjected to bias voltage to anisotropically etch the infrared light cut-off precursor layer. Thus, an infrared light cut-off filter was formed. In addition, a partition wall containing at least one of the formation material of the infrared light cut-off precursor layer, the formation material of the etching stopper layer, the reaction product of the infrared light cut-off precursor layer and the etching agent, and the reaction product of the formation material of the etching stopper layer and the etching agent was formed. Further, the thickness of the partition wall was 25 nm, and the partition wall was formed in a portion protruding from the infrared light filter in the side surface of the infrared light cut-off filter.

[0164] Further, the positive resist used as the etching mask was removed. The removal of the positive resist was performed by a spray cleaning device using a peeling solution (104, manufactured by Tokyo Ohka Kogyo Co., Ltd.).

[0165] Next, a plurality of microlenses having a height of 500 nm were formed on the infrared light cut-off filter and the infrared light filter using an etching method. Further, on the surface of the microlenses, an oxygen partition layer formed of SiO2 and having a thickness of 100 nm was formed using a plasma CVD method. Thus, a solid-state imaging device was obtained.

[0166] Explanation of Reference Numerals

[0167] 10... solid-state imaging device

[0168] 10F... filter for solid-state imaging device

[0169] 11... photoelectric conversion element

[0170] 12B... filter for blue

[0171] 12G…green filter

[0172] 12P…infrared light filter

[0173] 12R…red filter

[0174] 13, 23, 33, 53…etching stopper

[0175] 14…infrared light cut filter

[0176] 15, 25…oxygen barrier layer

[0177] 16, 26…microlens

[0178] 21…semiconductor substrate

[0179] 24, 34, 54…infrared light cut precursor layer

[0180] 47, 57…barrier wall

[0181] 54a…1st portion

[0182] 54b…2nd portion

[0183] 58…planarization layer

[0184] RP…resist pattern

Claims

1. A method of manufacturing a filter for a solid-state imaging device, wherein the method comprises the steps of: forming a color filter on a semiconductor substrate; forming an etching stopper layer on the semiconductor substrate and the color filter; forming an infrared light cut-off precursor layer on the etching stopper layer; forming a resist pattern covering a portion of the infrared light cut-off precursor layer on the color filter; and forming an infrared light cut-off filter by dry etching the infrared light cut-off precursor layer using the resist pattern, the etching rate of the infrared light cut-off precursor layer being different from the etching rate of the etching stopper layer, the step of forming the etching stopper layer comprises the step of forming the etching stopper layer on the color filter and on a portion of the semiconductor substrate where the color filter is not present, the step of forming the infrared light cut-off filter comprises the step of dry etching the infrared light cut-off precursor layer and the etching stopper layer to form a partition wall covering a side surface of the color filter and reflecting incident light.

2. The method of manufacturing a filter for a solid-state imaging device according to claim 1, wherein the step of forming the infrared light cut-off filter comprises the step of dry etching the infrared light cut-off precursor layer and the etching stopper layer to form the partition wall covering a side surface of the infrared light cut-off filter.

3. The method of manufacturing a filter for a solid-state imaging device according to claim 2, wherein the step of forming the etching stopper layer comprises the step of forming the etching stopper layer from polysiloxane, the step of forming the infrared light cut-off filter comprises the step of peeling the resist pattern from the infrared light cut-off filter using a peeling solution after the dry etching.

4. A method of manufacturing a filter for a solid-state imaging device, wherein the method comprises the steps of: forming a color filter on a semiconductor substrate; forming an etching stopper layer on the semiconductor substrate and the color filter; forming an infrared light cut-off precursor layer on the etching stopper layer; forming a resist pattern covering a portion of the infrared light cut-off precursor layer on the color filter; and forming an infrared light cut-off filter by dry etching the infrared light cut-off precursor layer using the resist pattern, the etching rate of the infrared light cut-off precursor layer being different from the etching rate of the etching stopper layer, the method further comprises the step of forming an infrared light filter on a portion of the semiconductor substrate where the color filter is not present before forming the etching stopper layer, the step of forming the infrared light cut-off precursor layer comprises the step of forming the infrared light cut-off precursor layer on a first portion on the color filter and on a second portion on the infrared light filter, the surface of the first portion being higher than or equal to the surface of the second portion in the thickness direction of the infrared light cut-off precursor layer. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The step of forming the infrared light-cut filter includes a step of dry-etching the infrared light-cut precursor layer and the etching stopper layer, thereby forming a partition wall that covers side surfaces of the infrared light-cut filter and reflects incident light.

5. The method of manufacturing a filter for a solid-state imaging device according to claim 4, wherein The step of forming the infrared light-cut filter includes a step of forming the infrared light-cut filter having a thickness that is less than or equal to a thickness of the color filter.

6. The method of manufacturing a filter for a solid-state imaging device according to claim 4, wherein The step of forming the etching stopper layer includes a step of forming the etching stopper layer from polysiloxane, The step of forming the infrared light-cut filter includes a step of peeling the resist pattern from the infrared light-cut filter using a peeling solution after the dry-etching.

7. The method of manufacturing a filter for a solid-state imaging device according to claim 4, wherein The method further includes a step of: forming an oxygen barrier layer that covers surfaces of the infrared light-cut filter and the infrared light filter, as viewed from a viewpoint opposite to a plane in which the semiconductor substrate extends; and forming a plurality of microlenses on the oxygen barrier layer.

8. The method of manufacturing a filter for a solid-state imaging device according to claim 4, wherein The method further includes a step of: forming a plurality of microlenses on a surface including surfaces of the infrared light-cut filter and the infrared light filter; and forming an oxygen barrier layer that covers surfaces of the plurality of microlenses.

9. A method of manufacturing a solid-state imaging device, wherein The method includes a step of: preparing a semiconductor substrate; and manufacturing a filter for a solid-state imaging device by the method of manufacturing a filter for a solid-state imaging device according to any one of claims 1 to 8.

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