JP2014033052A - Solid state imaging element and electronic information equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid state imaging element with high sensitivity, furthermore suppressed in reflection and absorption of incident light.SOLUTION: In order to reduce reflection at a silicon interface having a high refractive index, a silicon carbide film 8 having a high refractive index (although according to a composition, generally about 2.65) is formed on the rear surface of a P-well layer 2 of a silicon substrate via an insulating film 7, and, in order to make the film thickness optimum for a multiple interference effect, the silicon carbide film 8 is formed to have a film thickness so that the reflective index of the silicon carbide film 8 becomes a minimum value in a period corresponding to a film thickness, in a specified wavelength of incident light. The film thickness of the silicon carbide film 8 is formed to a thickness of 30 nm or more and 100 nm or less.

Description

  The present invention relates to a solid-state image pickup device such as a CMOS image sensor or a CCD image sensor configured by a plurality of semiconductor elements that photoelectrically convert image light from a subject and pick up an image, and an imaging unit using the solid-state image pickup device as an image input device. The present invention relates to an electronic information device such as a digital camera such as a digital video camera and a digital still camera, an image input camera such as a surveillance camera, a scanner device, a facsimile device, a television phone device, and a camera-equipped mobile phone device.

  In recent years, a back-illuminated solid-state image sensor has been developed as a highly sensitive solid-state image sensor. This back-illuminated solid-state imaging device is configured such that a circuit element, a wiring circuit, or the like is formed on the surface side of a silicon substrate, and light is incident from the back side of the silicon substrate to perform imaging.

  In such a conventional solid-state imaging device, the distance from the microlens to the photoelectric conversion device can be reduced, and restrictions on wiring and the like are eliminated. For this reason, more light can enter the photoelectric conversion region. In addition, in this conventional configuration, since the film configuration can be designed relatively freely from the micro lens or color filter on the back side to the photoelectric conversion region, various technologies for the film configuration on the back side are disclosed.

Patent Document 1 discloses a technique for suppressing dark current by forming a film having a negative fixed charge on the back surface side. At this time, if the film having a negative fixed charge has a high refractive index such as HfO ₂ (refractive index 2.05), Ta ₂ O ₅ (refractive index 2.16), or TiO ₂ (refractive index 2.20), the silicon interface It is shown that there is an anti-reflection effect at.

  Patent Document 2 discloses a technique for suppressing dark current by doping a p-type amorphous silicon compound with a p-type impurity.

  FIG. 9 is a longitudinal sectional view schematically showing an example of the configuration of the main part of a conventional back-illuminated solid-state imaging device disclosed in Patent Document 1.

  As shown in FIG. 9, the back-illuminated solid-state imaging device 100 includes a plurality of photodiodes 102 and a positive charge storage region 103 that are subjected to photoelectric conversion in a state where the element is isolated in the element isolation region 101. The semiconductor layer 104, the first film 105 having a negative fixed charge formed on the semiconductor layer 104 in the region where at least the photodiode 102 and the positive charge storage region 103 are formed, and having the negative fixed charge. And a second film 106 having a negative fixed charge, which is formed on the first film 105 and is made of a material different from that of the first film 105 having a negative fixed charge.

  A peripheral circuit portion 108 is provided adjacent to the outer peripheral side of the photodiode portion 107, and a light shielding film 110 is formed on the second film 106 with an insulating film 109 therebetween so as to cover the upper portion of the peripheral circuit portion 108. . A flattening film 111 for flattening the insulating film 109 and the light shielding film 110 is formed, and a color filter 112 having a predetermined color array and a condensing film thereon are provided on the insulating film 109 and the light shielding film 110 so as to correspond to the photodiodes 102, respectively. Each of the microlenses 113 is formed.

  A gate electrode 114 of the MOS transistor Tr1 is formed on the opposite surface side of these microlenses 113, and a wiring layer 115 made of metal wiring is further formed below. Here, three wiring layers 115 are shown. The gate electrode 114 and each wiring layer 115 are insulated by an interlayer insulating layer 116. The insulating layer 116 is supported by a support substrate (not shown).

  The first film 105 provided on the positive charge storage region 103 on the photodiode 102 and the second film 106 on the first film 105 suppress the dark current and reduce the film 105 and 106 having a negative fixed charge. Characteristic restrictions can be relaxed.

  FIG. 10 is a longitudinal sectional view schematically showing an example of the configuration of the main part of a conventional back-illuminated solid-state imaging device disclosed in Patent Document 2. As shown in FIG.

  As shown in FIG. 10, the back-illuminated solid-state imaging device 200 includes an imaging region in which a plurality of pixels 204 including a photoelectric conversion unit 202 and a signal scanning circuit unit 203 are arranged on a semiconductor substrate 201. In this imaging region, a plurality of photoelectric conversion units 202 are separated by a p-type semiconductor layer 205 for pixel separation.

  On the substrate surface side of the signal scanning circuit portion 203, an amplification transistor (not shown) formed in an interlayer insulating film 206 provided on the semiconductor substrate 201 on the signal scanning circuit formation surface side and a wiring layer 207 are provided. Yes.

On the back side of the substrate opposite to the surface of the semiconductor substrate 201 where the signal scanning circuit unit 203 is formed, a hole accumulation layer 208 is formed on the surface of the substrate. A silicon oxide film 209, a p-type amorphous silicon compound layer 210 (a-SiC (p) layer) provided on the silicon oxide film 209, and a semiconductor oxide substrate 209 on the light irradiation surface side of the back surface of the substrate, The planarizing layer 211 (SiO ₂ film), the color filter CF in the interlayer insulating film 212 provided on the planarizing layer 211, and the microlens 213 on the interlayer insulating film 212 are included.

  A hole accumulation layer 208 is formed of a p-type amorphous silicon compound layer 210 in the vicinity of the interface BF between the semiconductor substrate 201 and the silicon oxide film 209 on the light irradiation surface side. Thereby, depletion on the light irradiation surface side can be prevented and dark current can be reduced.

  In Patent Documents 1 and 2, the back surface film configuration for suppressing dark current has been described, but the back surface side antireflection function will be described.

  FIG. 11 is a longitudinal sectional view schematically showing an example of the configuration of the main part of a conventional back-illuminated solid-state imaging device.

  As shown in FIG. 11, the conventional back-illuminated solid-state imaging device 300 includes an SiN film in which incident light collected through a color filter 302 from a microlens 301 acts as an antireflection film from an interlayer insulating film 303. Further, the light enters from the back side of the P well layer 306 through the insulating film 305. Incident light from the back surface side of the P well layer 306 is focused on the photodiode 306 on the front surface side in the P well layer 306.

  On the surface between the photodiodes 306 in the P well layer 305, a wiring circuit 309 for reading out charges is provided via an insulating film.

  The interlayer insulating film 303 has a refractive index of 1.3 to 1.6, the SiN film 304 has a refractive index of 2.0, and the Si layer of the P well layer 306 has a refractive index of 4.0. Due to the difference in refractive index between the interlayer insulating film 303 and the P well layer 306, the SiN film 304 has an antireflection function of incident light by interposing a refractive index of 2.0 between them. Yes.

JP 2010-239116 A JP 2011-86877 A

  In the conventional back-illuminated solid-state imaging devices 100 and 200 disclosed in Patent Documents 1 and 2, a back-illuminated light incident side film is configured to suppress dark current, and light incident efficiency is increased. Has been adjusted accordingly. However, there is a strong demand from the market for improved sensitivity.

  In the conventional backside illumination type solid-state imaging device 200 disclosed in Patent Document 2, a p-type amorphous silicon compound layer 210 (a-SiC (p) layer) is provided on the irradiation surface of the semiconductor substrate 201. However, it is doped with p-type impurities here. Even if n-type impurity doping is used instead of p-type impurity doping, when the impurities are doped, light absorption becomes intense. Here, dark current is suppressed at the expense of the amount of light due to absorption of incident light. This causes a problem in light receiving sensitivity.

  The present invention solves the above-described conventional problems, and is a highly sensitive solid-state imaging device that further suppresses reflection and absorption of incident light, and a mobile phone with a camera using the solid-state imaging device as an image input device in an imaging unit, for example. An object is to provide an electronic information device such as a telephone device.

  The solid-state imaging device according to the present invention is a solid-state imaging device in which a plurality of light receiving units that photoelectrically convert incident light to form an image is two-dimensionally arranged, and an antireflection is provided above each of the plurality of light receiving units. The silicon carbide film for use is formed as the first transparent insulating film, thereby achieving the above object.

  Preferably, the silicon carbide film in the solid-state imaging device of the present invention is formed to have a film thickness at which the reflectance is a minimum value of a period corresponding to the film thickness of a specific wavelength of incident light.

  Further preferably, the silicon carbide film in the solid-state imaging device of the present invention is formed to a thickness of 30 nm or more and 100 nm or 200 nm or less.

  Further preferably, a silicon oxide film or a silicon oxynitride film having a thickness of more than 0 and not more than 30 nm and containing more oxygen than nitrogen is formed between the silicon carbide film and the semiconductor substrate in the solid-state imaging device of the present invention. ing.

Further preferably, the group III impurities of the silicon carbide film in the solid-state imaging device of the present invention are non-doped or formed to an impurity concentration of more than 0 and less than 1 × 10 ¹⁷ cm ⁻³ .

Still preferably, in the solid-state imaging device of the present invention, the Group V impurities other than the Group V nitrogen in the silicon carbide film are non-doped or formed at an impurity concentration exceeding 0 and less than 1 × 10 ¹⁷ cm ^−3. ing.

Further, preferably, the impurity nitrogen of the silicon carbide film in the solid-state imaging device of the present invention is non-doped or formed to an impurity concentration of more than 0 and less than 1 × 10 ¹⁷ cm ⁻³ .

  Further preferably, a silicon nitride film or a silicon oxynitride film is formed on the silicon carbide film in the solid-state imaging device of the present invention.

  Further preferably, the total thickness of the silicon carbide film and the silicon nitride film or the silicon oxynitride film thereon is formed to a thickness of 30 nm to 100 nm or 200 nm or less in the solid-state imaging device of the present invention.

  Further preferably, in the solid-state imaging device of the present invention, the silicon carbide film is formed or a film formed by combining the silicon carbide film and the silicon nitride film or silicon oxynitride film thereon is formed. A silicon oxide film or a second transparent insulating film of silicon oxynitride having a higher oxygen content than nitrogen is formed on the formed film, and a third transparent insulating film of silicon nitride film or silicon oxynitride film is formed on the second transparent insulating film. An insulating film is formed.

  Further preferably, the second transparent insulating film and the third transparent insulating film in the solid-state imaging device of the present invention are formed to have a film thickness that optimizes dark current or white spot defects by relaxing strain or stress of the semiconductor substrate. Has been.

  Further preferably, the thickness of the second transparent insulating film in the solid-state imaging device of the present invention is 30 nm or more and 200 nm or less.

  Further preferably, the film thickness of the third transparent insulating film in the solid-state imaging device of the present invention is not less than 30 nm and not more than 500 nm.

  Further preferably, the second transparent of the silicon carbide film, the silicon carbide film and the silicon nitride film or silicon oxynitride film thereon, or the silicon oxide film or the silicon oxynitride film on the silicon carbide film in the solid-state imaging device of the present invention. On the insulating film, or on the third transparent insulating film of the silicon nitride film or the silicon oxynitride film, or between the second transparent insulating film and the third transparent insulating film, there is a metal layer for light shielding or color mixing reduction. Is formed.

  Further preferably, in the solid-state imaging device according to the present invention, the first surface side of the semiconductor substrate has a wiring circuit for reading signal charges from the light receiving unit, and the light incident from the second surface side of the semiconductor substrate. Is a back-illuminated solid-state imaging device that performs photoelectric conversion.

  Furthermore, a CMOS solid-state image sensor or a CCD solid-state image sensor in the solid-state image sensor of the present invention is preferable.

  The electronic information device of the present invention uses the solid-state imaging device of the present invention as an image input device in an imaging unit, and thereby achieves the above object.

  With the above configuration, the operation of the present invention will be described below.

  In the present invention, a plurality of light receiving portions that photoelectrically convert incident light to image two-dimensionally are solid-state imaging devices, and an antireflection silicon carbide is provided above each of the plurality of light receiving portions. The film is formed as a first transparent insulating film.

  As a result, a silicon carbide film for antireflection is formed on the upper side including each of the plurality of light receiving portions, and silicon carbide having a high refractive index (generally about 2.65 depending on the composition) for antireflection. It is possible to obtain a highly sensitive solid-state imaging device in which reflection and absorption of incident light are further suppressed by the film.

  As described above, according to the present invention, since a silicon carbide film having a high refractive index (2.65) for prevention of reflection is provided above the plurality of light receiving portions, the incident light is reflected. A highly sensitive solid-state imaging device in which absorption is further suppressed can be obtained.

It is a longitudinal cross-sectional view which shows typically the principal part structural example of the solid-state image sensor in Embodiment 1 of this invention. It is a longitudinal cross-sectional view which shows typically the example of a principal part structure of the solid-state image sensor in Embodiment 2 of this invention. It is a longitudinal cross-sectional view which shows typically the principal part structural example of the solid-state image sensor in Embodiment 3 of this invention. (A) is a longitudinal cross-sectional view of the boundary part of the center light-receiving pixel area | region and the surrounding light-shielding pixel area | region in the solid-state image sensor of FIG. 3, (b) is a longitudinal cross-section which shows the modification in the boundary part of (a). FIG. It is a longitudinal cross-sectional view which shows typically the modification of the solid-state image sensor in Embodiment 3 of this invention. It is a longitudinal cross-sectional view which shows typically the example of a principal part structure of the solid-state image sensor in Embodiment 4 of this invention. The deformation of the solid-state imaging device of Embodiment 4 showing the case where the stress-relieving second transparent insulating film immediately below the metal layer in FIG. 6 is formed by etching to form a thin second transparent insulating film. It is a longitudinal cross-sectional view of an example. It is a block diagram which shows the schematic structural example of the electronic information apparatus which used either of the solid-state image sensors of Embodiment 1-4 of this invention for the imaging part as Embodiment 5 of this invention. FIG. 10 is a longitudinal sectional view schematically showing an example of the configuration of the main part of a conventional backside illumination type solid-state imaging device disclosed in Patent Document 1. It is a longitudinal cross-sectional view which shows typically the example of a principal part structure of the conventional backside illumination type solid-state image sensor currently disclosed by patent document 2. FIG. It is a longitudinal cross-sectional view which shows typically the example of a principal part structure of the conventional back irradiation type solid-state image sensor.

  Embodiments 1 and 2 of the solid-state imaging device of the present invention, and implementation of an electronic information device such as a mobile phone device with a camera using the embodiments 1 and 2 of the solid-state imaging device as an image input device in an imaging unit are described below. The third embodiment will be described in detail with reference to the drawings. In addition, each thickness, length, etc. of the structural member in each figure are not limited to the structure to illustrate from a viewpoint on drawing preparation.

(Embodiment 1)
FIG. 1 is a vertical cross-sectional view schematically showing an exemplary configuration of a main part of a solid-state imaging device according to Embodiment 1 of the present invention.

  In FIG. 1, a solid-state imaging device 1 according to Embodiment 1 includes a plurality of light receiving units 3 (a plurality of light receiving units 3) that photoelectrically convert incident light from a subject on the surface side of a P well layer 2 of a silicon substrate as a semiconductor substrate. Are arranged in a two-dimensional matrix. On the surface of the P well layer 2 between the light receiving portions 3, a wiring circuit 5 including a circuit element for reading out charges of each pixel is disposed via an insulating film 4. An interlayer insulating film 6 is disposed so as to embed on each wiring circuit 5.

  An antireflection silicon carbide film 8 (SiC film) is disposed on the back surface side of the P well layer 2 via an insulating film 7, and a predetermined color arrangement is provided on the silicon carbide film 8 via a planarizing film 9. A color filter 10 (for example, Bayer array) is provided. Furthermore, a microlens 12 that collects incident light to each light receiving portion 3 is disposed via a planarizing film 11 that is embedded on the color filter 10 and planarizes the surface. These color filter 10 and microlens 12 are arranged corresponding to each light receiving unit 3.

  The silicon carbide film 8 (SiC film) is formed by adjusting its thickness for antireflection. Although the silicon carbide film 8 varies depending on the composition, the refractive index is high around 2.65. Compared with 2.0 of silicon nitride film (SiN film) and 1.95 of silicon oxynitride film (SiON film) that are often used conventionally, the refractive index is overwhelmingly high.

In addition to this, the silicon carbide film 8 (SiC film) has a high refractive index, so that reflection of incident light is considered to be suppressed. HfO ₂ (refractive index 2.05), Ta ₂ O ₅ (refractive index 2.16). ) And TiO ₂ (refractive index 2.20), the refractive index is even higher. For this reason, since the silicon layer (Si layer) forming the semiconductor substrate is close to a high refractive index of about 4.0 (the refractive index changes depending on the wavelength in the visible light region), the refractive index of the planarizing film 9 is 1. 6 and a silicon layer (Si layer) having a refractive index of 4.0, which is higher than that of a conventional silicon nitride film (SiN film) having a refractive index of 2.0. The reflection at the interface of the silicon carbide film 8 (SiC film) can be suppressed by providing the 2.65 silicon carbide film 8 (SiC film) for antireflection.

  The reflectance of the silicon carbide film 8 changes periodically according to the film thickness due to the multiple interference effect. Therefore, the film is formed to have a film thickness that has a minimum value of the period according to the film thickness of the specific wavelength of the incident light. The specific wavelength may be considered as the wavelength of visible light, and when calculated, the film thickness of the silicon carbide film 8 is 30 nm or more and 100 nm (λ / 4, λ is the wavelength) or 200 nm (when 3λ / 4, λ is the wavelength) It is desirable to form the following thickness. When the thickness of the silicon carbide film 8 is thinner than 30 nm, the antireflection effect is greatly lost. When the thickness of the silicon carbide film 8 is thicker than 100 nm, light absorption due to the film thickness becomes too large. Usually, the silicon carbide film 8 is formed to have a film thickness at which the green reflectance that contributes most to the luminance is a minimum value. In this case, the reflectivity is not optimal for red or blue. Here, the wavelength λ means the wavelength in the film, and means the wavelength in vacuum divided by the refractive index of the film.

  On the other hand, when the film is formed with a film thickness that minimizes the reflectance of blue light, it is possible to increase the blue sensitivity, which is difficult to increase the original light receiving sensitivity. Furthermore, red light reception sensitivity and further infrared light reception sensitivity may be required. In such a case, the film may be formed with a film thickness at which the reflectance of red light or infrared light becomes a minimum value. .

  The reflectance of the silicon carbide film 8 periodically becomes a minimum value when each color light has a quarter wavelength or a quarter wavelength. Since the thickness of the silicon carbide film 8 is thicker and the light transmittance is reduced by that amount when the wavelength of each color light is a quarter wavelength than when the wavelength of each color light is a quarter wavelength, The optimum value is obtained when the wavelength is 1/4. The half wavelength of red light is 55 nm, the half wavelength of green light is 45 nm, and the half wavelength of blue light is 35 nm. Here, since it matches with green light, the film thickness of the silicon carbide film 8 is set to 45 nm.

  A silicon carbide film 8 functioning as an antireflection film is provided, and a light receiving portion 3 (charge storage region) in the P well layer 2 of the semiconductor substrate, a wiring circuit 5 for driving pixels, and the like are provided on the opposite side of the light incident side. The present invention can be applied to the back-illuminated solid-state imaging device 1. The charge storage region of the light receiving unit 3 is described as an n-type that stores general electrons, but a p-type that stores holes can also be used.

At this time, the impurity doping amount of group III (such as boron B or aluminum Al) or group V (neighboring P, nitrogen N, arsenic As) of the silicon carbide film 8 is suppressed, and the impurity doping amount is 0 or more and 1 × 10 ¹⁷ cm ^−. Light absorption can be suppressed by setting it to less than ³ or less. In particular, the silicon carbide film 8 may have an impurity doping amount of less than 1 × 10 ¹⁷ cm ⁻³ or less, but more preferably non-doped, that is, the impurity doping amount is zero.

In short, the group III impurities of the silicon carbide film 8 are non-doped or formed so that the impurity concentration exceeds 0 and is less than 1 × 10 ¹⁷ cm ⁻³ or less. Further, the V group impurities other than the V group nitrogen N in the silicon carbide film 8 are non-doped or formed so that the impurity concentration exceeds 0 and is less than 1 × 10 ¹⁷ cm ⁻³ or less. Further, the nitrogen N concentration of the silicon carbide film 8 is non-doped or formed to exceed 0 and less than or less than 1 × 10 ¹⁷ cm ⁻³ .

In particular, group III boron B is charged as compared with aluminum Al, so that dark current can be suppressed, but light is absorbed accordingly. When aluminum Al reaches the Si semiconductor substrate, it causes dark current. In addition, the P next to the group V, the nitrogen N, and the arsenic As all have the effect of suppressing dark current, but absorb light. Group V nitrogen N has good solubility with silicon carbide and is easily doped with impurities. As a result, light is absorbed by the nitrogen N. In short, the dark current can be suppressed by doping impurities, but the light transmittance is deteriorated. Therefore, here, the impurities are non-doped. However, impurities such as boron B of group III or P adjacent to group V are doped into the silicon carbide film 8. Even so, the minimum impurity concentration is less than or less than 1 × 10 ¹⁷ cm ⁻³ .

An insulating film 7 is provided on the back side of the semiconductor substrate on the P well layer 2. That is, an oxide film (SiO ₂ film) or a silicon oxynitride film (SiON film) containing more oxygen than nitrogen is formed as the insulating film 7 with a film thickness of 30 nm or less between the silicon carbide film 8 and the silicon substrate. ing.

In short, a silicon oxide film (SiO ₂ film) having a thickness of 30 nm or less or a silicon oxynitride film (SiON film) containing more oxygen than nitrogen is formed as an insulating film 7 on the P well layer 2 to be generated at the silicon interface. The density of interface states is lowered. The film forming method is most preferably thermal oxidation, but a method of depositing a silicon oxide film may be used. Alternatively, a method using an SOI substrate may be used. In order to minimize light reflection, it is desirable that the film is thin. If dark current and white spot defects can be suppressed, the insulating film 7 should be removed.

A planarizing layer 9 is formed on the silicon carbide film 8 to improve planarization or adhesion. For this, an acrylic material or the like may be formed by spin coating, or a silicon oxide film (SiO ₂ film) or a silicon oxynitride film (SiON film) may be deposited as the planarizing layer 9. .

  The above description will be further organized and described.

In the solid-state imaging device 1 of Embodiment 1, in order to reduce reflection at the silicon interface having a high refractive index, a silicon carbide film 8 having a high refractive index (2.65) is formed on the back surface of the P well layer 2 of the silicon substrate. In order to optimize the film thickness by the multiple interference effect, the silicon carbide film 8 is formed with a film thickness at which the reflectance of the specific wavelength of the incident light is a minimum value of the period according to the film thickness. At this time, it is desirable to suppress doping of Group III or Group V impurities in the silicon carbide film 8 so that the impurity concentration exceeds 0 and is less than or equal to 1 × 10 ¹⁷ cm ⁻³ . Typical examples of Group III (Group 13) elements include boron B and aluminum Al. Typical examples of Group V (Group 15) elements include nitrogen N and phosphorus P. When these elements enter the silicon carbide film 8, impurity levels are formed and light is absorbed. For this reason, non-doping is desirable if possible. In particular, it is important to control the concentration of nitrogen N that is easily mixed. As a result, the solid-state imaging device 1 having a high light receiving sensitivity can be obtained by reducing the reflectance by the first embodiment and suppressing light absorption by the silicon carbide film 8.

  Preferably, the silicon carbide film 8 is formed to a thickness of 30 nm or more and 100 nm or less in order to reduce the reflectance and suppress light absorption, thereby minimizing the reflectance. Preferably, an insulating film 7 made of a silicon oxide film of more than 0 and 30 nm or less or a silicon oxynitride film having a higher oxygen content than nitrogen is formed between the silicon carbide film 8 as the first transparent insulating film and the semiconductor substrate. By doing so, the density of interface states generated at the silicon interface can be reduced, the generation of dark current can be suppressed, and the improvement in light receiving sensitivity can be achieved.

  As described above, according to the first embodiment, in the solid-state imaging device 1 in which the plurality of light receiving units 3 that photoelectrically convert incident light to image the two-dimensionally arranged, the portions directly above the plurality of light receiving units 3 are arranged. An antireflective silicon carbide film 8 is formed as a first transparent insulating film on the upper side. As a result, the silicon carbide film 8 having a high refractive index (2.65) for preventing reflection suppresses reflection and light absorption of incident light and increases the amount of light reaching each light receiving unit 3, thereby achieving high light receiving sensitivity. Can do.

(Embodiment 2)
In the first embodiment, the case where the high-refractive-index silicon carbide film 8 for preventing reflection is provided above each light receiving unit 3 has been described. In the second embodiment, instead of the silicon carbide film 8, a description will be given later. A case where the silicon carbide film 8A and the silicon nitride or silicon oxynitride film 13 thereon are provided to prevent reflection by sequentially changing the refractive index will be described.

  FIG. 2 is a longitudinal sectional view schematically showing an example of the configuration of the main part of a solid-state imaging device according to Embodiment 2 of the present invention. In FIG. 2, members having the same functions and effects as those of the constituent members of FIG.

  In FIG. 2, the solid-state imaging device 1 </ b> A according to Embodiment 2 includes a plurality of light receiving units 3 as two or more photodiodes that photoelectrically convert incident light on the surface side of a P well layer 2 of a silicon substrate. Arranged in a matrix. On the surface of the P well layer 2 between the adjacent light receiving portions 3, a wiring circuit 5 including a circuit element for reading out charges of each pixel is disposed via an insulating film 4. An interlayer insulating film 6 is disposed so as to embed on each wiring circuit 5.

  On the back side of the P well layer 2, a silicon carbide film 8A (SiC film) for reflection prevention and light transmission is formed through an insulating film 7, and a silicon nitride film or a silicon oxynitride film 13 is formed thereon. ing. The total film thickness of the silicon carbide film 8A and the silicon nitride or silicon oxynitride film 13 is formed to a thickness of 30 nm to 100 nm. Therefore, the thickness of the silicon carbide film 8A of the second embodiment can be made thinner than the thickness of the silicon carbide film 8 of the first embodiment. In short, a portion of the thickness of the silicon carbide film 8 of the first embodiment that is not less than 30 nm and not more than 100 nm can be applied to the silicon nitride or silicon oxynitride film 13. The total film thickness of the silicon carbide film 8A and the silicon nitride or silicon oxynitride film 13 does not become larger than the film thickness of the silicon carbide film 8 of the first embodiment.

  Further, a color filter 10 having a predetermined color arrangement (for example, a Bayer arrangement) is disposed thereon via a planarizing film 9, and further, a micro that collects incident light on each light receiving unit 3 via a planarizing film 11 thereon. A lens 12 is formed corresponding to each light receiving portion 3.

  The silicon carbide film 8A (SiC film) has a refractive index of 2.65 and is formed by adjusting its thickness for antireflection. The refractive index of 2.65 of the silicon carbide film 8A is overwhelmingly higher than that of the silicon nitride film (SiN film) 2.0 and the silicon oxynitride film (SiON) of about 1.95.

  A silicon nitride film (SiN film) or a silicon oxynitride film 13 (SiON film) is formed on the silicon carbide film 8A in contact with the silicon carbide film 8A. As a result, the film materials are formed in the order of silicon, silicon carbide, silicon nitride film, or silicon oxynitride having a high refractive index from the bottom to the top. As a result, the refractive index is sequentially increased from the refractive index 2.0 of the silicon nitride film or the refractive index 1.95 of the silicon oxynitride film to the refractive index 4.0 of the silicon substrate through the refractive index 2.65 of the silicon carbide film 8A. Reduced and changed. The interface reflection that occurs when the refractive index change is steep can be suppressed, and the light transmittance to the silicon substrate can be improved by the silicon carbide film 8A and the silicon nitride film or the silicon oxynitride film 13. In short, the greater the change in refractive index in the upper and lower layers, the more reflected light increases and the light transmission deteriorates.

  As described above, according to the second embodiment, in the solid-state imaging device 1A in which the plurality of light receiving units 3 that photoelectrically convert the incident light to be imaged are arranged in a two-dimensional manner, each of the plurality of light receiving units 3 is directly above. An antireflection silicon carbide film 8A is formed as a first transparent insulating film above the silicon nitride film or silicon oxynitride film 13 so as to be in contact with the silicon carbide film 8A, and a silicon carbide film 8A; The total thickness of the silicon nitride film or the silicon oxynitride film 13 is formed to a thickness of 30 nm to 100 nm. As a result, the refractive index up to the silicon substrate can be changed in a finer stepwise manner, and reflection can be further suppressed to achieve high light receiving sensitivity.

(Embodiment 3)
In the first embodiment, a case where a high-refractive-index silicon carbide film 8 for preventing reflection is provided above each light receiving portion 3 will be described. In the second embodiment, a silicon carbide film is provided above each light receiving portion 3. 8A and a case in which the silicon nitride or silicon oxynitride film 13 provided thereon is provided to prevent reflection by sequentially changing the refractive index. In the third embodiment, the silicon carbide film 8B or The silicon carbide film 8B and the silicon nitride film or silicon oxynitride film 13 formed thereon are formed, and a silicon oxide film or a silicon oxynitride film having a higher oxygen content than nitrogen is formed on the formed film. A second transparent insulating film 14 to be described later is formed for stress relaxation, and a third transparent insulating film to be described later of a silicon nitride film or a silicon oxynitride film is formed on the second transparent insulating film 14. It will be described for forming a film 13.

  FIG. 3 is a vertical cross-sectional view schematically showing an exemplary configuration of a main part of a solid-state imaging device according to Embodiment 3 of the present invention. 4A is a longitudinal sectional view of the boundary portion between the central light-receiving pixel region and the surrounding light-shielding pixel region in the solid-state imaging device of FIG. 3, and FIG. 4B is the boundary portion of FIG. It is a longitudinal cross-sectional view which shows a modification. FIG. 4A and FIG. 4B show an example of a film configuration when a light-shielding pixel is formed with a light-shielding metal film. In FIG. 4B, when the shape of the metal layer 15 that is a light shielding film is formed by etching, the stress-relieving second transparent insulating film 14 is shaved and thinned to the second transparent insulating film 14A. 3 and 4, members having the same functions and effects as those of the constituent members of FIG. 1 are described with the same reference numerals.

  3 and 4A, the solid-state imaging device 1B according to the third embodiment includes a plurality of photodiodes as a plurality of photodiodes that photoelectrically convert incident light on the surface side of the P well layer 2 of the silicon substrate. The light receiving portions 3 are two-dimensionally arranged in a matrix. On the surface of the P well layer 2 between the adjacent light receiving portions 3, a wiring circuit 5 including a circuit element for reading out charges of each pixel is disposed via an insulating film 4. An interlayer insulating film 6 is disposed so as to embed on each wiring circuit 5.

A silicon carbide film 8B (SiC film) for preventing reflection is formed as a first transparent insulating film on the back side of the P well layer 2 via an insulating film 7, and a silicon oxide film (SiO ₂ film) is formed thereon. Alternatively, a second transparent insulating film 14 is formed as a stress relaxation layer of a silicon oxynitride film (SiON film) containing more oxygen than nitrogen, and a silicon nitride film or silicon oxynitride film 13 is further formed thereon as a third transparent film. The insulating film is formed, and the total thickness of the silicon carbide film 8B and the silicon nitride or silicon oxynitride film 13 is 30 nm or more and 100 nm or less.

  Further, a color filter 10 having a predetermined color arrangement (for example, a Bayer arrangement) is disposed thereon via a planarizing film 9, and further, a micro that collects incident light on each light receiving unit 3 via a planarizing film 11 thereon. A lens 12 is formed corresponding to each light receiving portion 3.

  As described above, the silicon carbide film 8B and the silicon nitride film or the silicon oxynitride film 13 are formed with a film thickness that optimizes the light reflection prevention function and optimizes the light transmission, thereby optimizing the light receiving sensitivity.

However, with this film thickness, there is a possibility that the tensile stress of silicon (Si) can be relaxed and metal contamination to the silicon substrate cannot be suppressed. In particular, since the metal layer 15 is formed in the light-shielding pixel region around the light-receiving pixel region shown in FIG. 4A, tensile stress is generated in the silicon substrate. Therefore, in the third embodiment, as a stress relaxation layer, in order to solve these problems, oxygen is introduced between the silicon carbide film 8B and the silicon nitride film or the silicon oxynitride film 13 from the silicon oxide film (SiO ₂ film) or nitrogen. A second transparent insulating film 14 of a silicon oxynitride film (SiON film) with a high content is formed.

As described above, the second transparent insulating film 14 of the silicon oxide film or the silicon oxynitride film having a higher oxygen content than nitrogen is laminated on the silicon carbide film 8B as the first transparent insulating film. A silicon nitride film or a silicon oxynitride film 13 is formed thereon as a third transparent insulating film. As a result, the effect of optimizing the multiple reflection of the silicon carbide film 8B, which is the first transparent insulating film, can be reliably maintained, and the distance between the microlens 12 and the P well layer 2 of the semiconductor substrate can be extended more than necessary. It is possible to prevent light reception sensitivity deterioration and color mixing. At this time, the film thickness of the second transparent insulating film 14 for stress buffering needs to be sufficient. When the film thickness is 20 nm, the distance between the silicon carbide film 8B and the silicon nitride film or the silicon oxynitride film 13 is sufficient. Therefore, the reflection is small and the stress relaxation effect is small. Therefore, the film thickness is set to 30 nm to 500 nm, preferably 30 nm to 200 nm. Here, the second transparent insulating film 14 for stress buffering is formed at 70 nm. Forming. When the second transparent insulating film 14 for stress buffering exceeds 500 nm, although there is a stress buffering effect, the light transmittance is deteriorated by the thicker film thickness. In short, the second transparent insulating film 14 of the silicon oxide film (SiO ₂ film) or the silicon oxynitride film (SiON film) containing more oxygen than nitrogen is opposite to the direction in which the metal layers 15 and 16 warp. Acts so that they cancel each other. Further, since the silicon carbide film 8B as the first transparent insulating film is also warped in the opposite direction with respect to the warping direction of the metal layers 15 and 16, it acts in a direction to cancel each other.

  Further, a third transparent insulating film of a silicon nitride film or a silicon oxynitride film 13 is laminated on the second transparent insulating film 14 for stress buffering. As a result, the tensile stress of the silicon substrate can be relaxed and metal contamination on the silicon substrate can be suppressed. Here, it is necessary to adjust for each solid-state imaging device 1B in order to optimize the tensile stress. At this time, since the influence of the upper and lower films on the semiconductor substrate is weakened due to the multiple interference effect through the second transparent insulating film 14, the thickness of the silicon nitride film or the silicon oxynitride film 13 as the third transparent insulating film is reduced. Even if it is set freely, the influence on the light receiving sensitivity can be suppressed. Preferably, by making the thickness of the silicon nitride film or silicon oxynitride film 13 as the third transparent insulating film 30 nm or more and 500 nm or less, an effect of reducing tensile stress and suppressing metal contamination can be obtained, and It is possible to prevent the distance between the lens 12 and the silicon substrate from being extended more than necessary, and to prevent deterioration of light receiving sensitivity and color mixing. If the thickness of the silicon nitride film or the silicon oxynitride film 13 as the third transparent insulating film is smaller than 30 nm, the strain prevention effect cannot be expected. Here, a silicon nitride film or a silicon oxynitride film 13 is formed as a third transparent insulating film at 200 nm. In the case of 200 nm, the effect of relaxing tensile stress and suppressing metal contamination are sufficient. When the film thickness of the silicon nitride film or the silicon oxynitride film 13 as the third transparent insulating film exceeds 500 nm, no further film thickness is required. In short, since the silicon nitride film or the silicon oxynitride film 13 as the third transparent insulating film is warped in the opposite direction with respect to the warping direction of the metal layers 15 and 16, they cancel each other.

  In the third embodiment, the second transparent insulating film 14 is formed on the silicon carbide film 8B, and the silicon nitride film or the silicon oxynitride film 13 is formed on the second transparent insulating film 14 as the third transparent insulating film. However, the present invention is not limited to this, a silicon carbide film 8A is formed above each light receiving portion 3, a silicon nitride film or a silicon oxynitride film 13 is formed on the silicon carbide film 8A, and a silicon nitride film or a silicon oxynitride film is formed. A second transparent insulating film 14 for stress relaxation may be formed on 13, and a silicon nitride film or a silicon oxynitride film 13 may be formed on the second transparent insulating film 14 as a third transparent insulating film. This also makes it possible to relieve the tensile stress of the silicon substrate by the second transparent insulating film 14 and suppress metal contamination to the silicon substrate. This is shown in FIG.

  FIG. 5 is a longitudinal sectional view schematically showing a modification of the solid-state imaging device according to Embodiment 3 of the present invention.

  In FIG. 5, in the solid-state imaging device 1 </ b> C of the third embodiment, a silicon carbide film 8 </ b> C is formed above each light receiving unit 3. A silicon nitride film or a silicon oxynitride film 13a is formed on the silicon carbide film 8C. A second transparent insulating film 14 for stress relaxation is formed on the silicon nitride film or silicon oxynitride film 13a. Further, a silicon nitride film or a silicon oxynitride film is formed on the second transparent insulating film 14 as the third transparent insulating film 13b.

  As described above, as in the third embodiment, the silicon carbide film 8B or the silicon carbide film 8C and the silicon nitride film or silicon oxynitride film 13a thereon are combined so as to minimize the loss of reflection and absorption sensitivity. By optimizing the thickness of the deposited film to increase the light incident efficiency and laminating the second transparent insulating film 14 for stress relaxation thereon, the multiple reflection of the first transparent insulating film (silicon carbide film 8B or 8C) is achieved. The effect of optimization can be maintained. Further, the third transparent insulating film 13b is laminated thereon and the film thickness is adjusted, so that the tensile stress of the silicon substrate can be relieved and the metal contamination to the silicon substrate can be suppressed. As a result, the solid-state imaging device 1B or 1C according to the third embodiment can prevent the occurrence of dark current and white point defects while further suppressing the reflection and absorption of incident light to increase the light receiving sensitivity.

  Also in this case, the thickness of the second transparent insulating film 14 is not less than 30 nm and not more than 500 nm, preferably not less than 30 nm and not more than 200 nm, so that the multiple reflection of the first transparent insulating film (silicon carbide film 8C) can be optimized. The effect can be reliably maintained, the distance between the microlens 12 and the silicon substrate can be prevented from being unnecessarily extended, and the light receiving sensitivity and color mixing can be prevented from deteriorating.

  Further, by setting the thickness of the third transparent insulating film 13b to 30 nm or more and 500 nm or less, preferably 30 nm or more and 200 nm or less, the tensile stress of the silicon substrate is relieved and metal contamination to the silicon substrate is suppressed. Is possible. Here, in order to optimize the tensile stress, the film has an appropriate film thickness for each solid-state imaging device 1B or 1C. However, since the second transparent insulating film 14 is present, the film thickness of the third transparent insulating film 13b is increased. Even if it is set freely, the influence on the light receiving sensitivity can be suppressed.

  Here, when the thickness of the third transparent insulating film 13b is adjusted, the film thickness is adjusted so as to minimize dark current or white spot defects. However, other films such as the first transparent insulating film (silicon carbide film) 8B or 8C), the second transparent insulating film 14, the color filter 10 and the microlens 12 must be taken into consideration.

(Embodiment 4)
In the third embodiment, since the light shielding metal layer 15 is formed in the light shielding pixel area around the light receiving pixel area as shown in FIG. 4A, tensile stress is generated in the silicon substrate. The case where the second transparent insulating film 14 is formed as a silicon oxide film (SiO ₂ film) or a silicon oxynitride film (SiON film) containing more oxygen than nitrogen has been described. A case of a stress relaxation film configuration when forming a metal layer with a metal film for use will be described.

  FIG. 6 is a vertical cross-sectional view schematically illustrating an exemplary configuration of a main part of a solid-state imaging device according to Embodiment 4 of the present invention. In FIG. 6, the same reference numerals are given to members having the same functions and effects as the constituent members in FIG. 1.

In FIG. 6, the solid-state imaging device 1 </ b> E of the fourth embodiment forms an antireflection silicon carbide film 8 </ b> E (SiC film) as a first transparent insulating film on the back surface of the P well 2 via the insulating film 7. A second transparent insulating film 14 is formed thereon as a stress relaxation layer of a silicon oxide film (SiO ₂ film) or a silicon oxynitride film (SiON film) containing more oxygen than nitrogen. A metal layer 16 for reducing color mixing is formed at the boundary. A silicon nitride film or a silicon oxynitride film 13 is formed on the second transparent insulating film 14 and the metal layer 16.

  Further, a color filter 10 having a predetermined color arrangement (for example, a Bayer arrangement) is disposed thereon via a planarizing film 9, and further, a micro that collects incident light on each light receiving unit 3 via a planarizing film 11 thereon. A lens 12 is formed corresponding to each light receiving portion 3.

  Although not specifically described in the fourth embodiment, the silicon carbide film 8E and the silicon nitride film (SiN film) or the silicon oxynitride film (SiON film) 13 on or between the transparent insulating film and the silicon carbide film 8E are provided. The metal layer 16 for reducing color mixing may be formed through the second transparent insulating film 14 for stress relaxation. In FIG. 4A described above, the light shielding metal layer 15 is formed between the stress-relieving second transparent insulating film 14 and the silicon nitride film (SiN film) or the silicon oxynitride film (SiON film) 13. By doing so, contamination from the metal layer can be suppressed by the silicon carbide film 8E or the silicon carbide film 8E and the silicon nitride film or silicon oxynitride film 13 formed thereon or the transparent insulating film. At this time, when the light shielding metal layer 15 or the color mixing reduction metal layer 16 is formed on the light incident side on the second transparent insulating film 14, the light shielding metal layer 15 or metal layer is formed by the second transparent insulating film 14. 16 can relieve the stress on the silicon substrate side.

  A silicon nitride film or a silicon oxynitride film 13 as a third transparent insulating film is formed with a film thickness that optimizes the dark current or white spot defect of the light-shielded pixel. It is known that the metal layer is a film having a large stress, but the large stress generated in the metal layer can be adjusted by forming the third transparent insulating film on top of each other. White spot defects can be optimized.

  Preferably, the silicon carbide film 8B or 8E in a region where the light shielding metal layer 15 or the color mixing reduction metal layer 16 is provided, or a film in which the silicon carbide film 8E and the silicon nitride film or silicon oxynitride film are combined. Alternatively, the thickness of the second transparent insulating film 14 for stress relaxation or the region to be the silicon nitride film or the silicon oxynitride film 13 as the third transparent insulating film thereon is set to the other metal layer 15 for light shielding or The thickness can be changed with respect to the thickness of the region where the metal layer 16 for reducing color mixture is not provided. For example, in order to further alleviate the stress caused by the metal film or to appropriately suppress the contamination from the metal layer 16 for reducing color mixing, the second transparent insulating film 14 for stress relaxation is placed in the region where the metal layer 16 is present. Thus, the thickness can be adjusted so as to be thicker than the region where other light is incident. This is shown in FIG. Similarly, in FIG. 4B, when the shape of the light shielding metal layer 15 is formed by etching, the stress-relieving second transparent insulating film 14 is shaved and thinned to the second transparent insulating film 14A. Yes.

  FIG. 7 shows the present embodiment in which the second transparent insulating film 14 for stress relaxation immediately below it is shaved to form a thin second transparent insulating film 14F when forming a shape by etching the metal layer 16 of FIG. It is a longitudinal cross-sectional view of the modification of the solid-state image sensor of 4.

  In FIG. 7, the solid-state imaging device according to the modified example of the fourth embodiment has a thickness of the second transparent insulating film 14 </ b> F for stress relaxation in a region where the metal layer 16 for color mixing reduction is present, and other light incident incident light. The thickness of the second transparent insulating film 14F for stress relaxation in the region is different. The film thickness of the second transparent insulating film 14F for stress relaxation in the region where the metal layer 16 for color mixing reduction is present is the film thickness of the second transparent insulating film 14F for stress relaxation in the other light incident region. It is configured to be thicker. In short, when the metal layer 16 is formed by etching, the stress-relieving second transparent insulating film directly underneath is shaved to form a thin second transparent insulating film 14F.

  In order to prevent light from entering, it is desirable that the light shielding metal layer 15 and the color mixing reduction metal layer 16 be closer to the semiconductor substrate as the light shielding metal film. However, the second transparent insulating film 14 or 14F for stress relaxation is formed on at least the silicon carbide film 8E or 8F, or on the film formed by combining the silicon carbide film 8E or 8F and the silicon nitride film or silicon oxynitride film thereon. By forming the second transparent insulating film 14 or 14F for stress relaxation, the relaxation of the tensile stress and metal contamination of the silicon substrate can be suppressed, and dark current and white spot defects can be further suppressed. Further, when a silicon nitride film or a silicon oxynitride film as a third transparent insulating film is formed on the second transparent insulating film 14 or 14F, the stress on the light shielding metal layer 15 and the metal film 16 is further alleviated, and the dark current is reduced. And white spot defects can be further suppressed. Further, the second transparent insulating film 14 or 14F for stress relaxation may be formed on the third transparent insulating film of the fourth embodiment. 6 and 7, a silicon nitride film or a silicon oxynitride film as a third transparent insulating film may be formed on the second transparent insulating film 14 or 14F.

  As described above, according to the fourth embodiment, it is possible to obtain a highly sensitive solid-state imaging device 1E or 1F that further suppresses reflection and absorption of incident light.

  As described above in the fourth embodiment, in addition to the first embodiment, the silicon carbide film 8B or 8E or the silicon carbide film 8B or 8E in the region where the light shielding metal layer 15 or the color mixing reduction metal layer 16 is provided. FIG. 7 shows an example in which the thickness of the region that is the thickness of the second transparent insulating film 14 or the third transparent insulating film is changed by combining the silicon nitride film or the silicon oxynitride film thereon and the second transparent insulating film 14 or the third transparent insulating film. Yes. In order to suppress the relaxation of tensile stress and metal contamination while optimizing the light receiving sensitivity, the first transparent insulating film (silicon carbide film 8B or 8E) or the second transparent insulating film 14 as shown in FIG. It is desirable to change the film thickness of the silicon nitride film or the silicon oxynitride film as the third transparent insulating film so that the light shielding metal layer 15 or the metal layer 16 is thicker. On the other hand, from the viewpoint of preventing color mixing, it is desirable to make the place where the metal layer 16 is thinner, so adjustment is necessary.

  In the first to fourth embodiments, the wiring circuit 5 for reading the signal charge from the light receiving unit 3 is provided on the first surface (front surface) side of the semiconductor substrate, and is incident from the second surface (back surface) side of the semiconductor substrate. The back-illuminated solid-state imaging device that photoelectrically converts the emitted light has been described, but the antireflection function of the above-described Embodiments 1 to 4 of the present invention can be applied even to a front-illuminated solid-state imaging device, and The antireflection function of the first to fourth embodiments can be applied to either a CMOS solid-state image sensor or a CCD solid-state image sensor.

  In the CMOS type solid-state imaging device, a light receiving portion is provided as a photoelectric conversion portion for each pixel portion in each of the plurality of pixel portions, and a signal charge from the light receiving portion is transferred to the charge voltage conversion portion adjacent to the light receiving portion. And the charge transfer transistor for performing the signal conversion and the signal charge transferred by the charge transfer transistor to the charge voltage conversion unit for each light receiving unit is converted into a voltage, amplified in accordance with the converted voltage, and read out as an imaging signal for each pixel unit Read circuit.

  In the CCD type solid-state imaging device, a light receiving portion is provided as a photoelectric conversion portion for each pixel portion in each of the plurality of pixel portions, and adjacent to the light receiving portion, signal charges from the light receiving portion are transferred in a predetermined direction. And a gate electrode for controlling the charge transfer of the read signal charge and a metal light shielding film thereon.

  Although not described in detail in the third and fourth embodiments, the silicon carbide film, the silicon carbide film and the silicon nitride film or the silicon oxynitride film 13 or 13a thereon, or the silicon oxide film are used. Alternatively, on the second transparent insulating film 14 of the silicon oxynitride film, on the third transparent insulating film of the silicon nitride film or silicon oxynitride film 13 or 13b, or between the second transparent insulating film 14 and the third transparent insulating film. In addition, the light shielding or color mixing reduction metal layers 15 and 16 may be formed. Each of these films is warped in the opposite direction to the warp direction of the metal layers 15 and 16, and thus acts in a direction in which stress on the silicon substrate is relieved.

  It is possible to obtain a highly sensitive solid-state imaging device 1E or 1F that suppresses reflection and absorption at the time of incidence, and an electronic information device equipped with such a solid-state imaging device 1E or 1F. This will be described in the fifth embodiment.

(Embodiment 5)
FIG. 8 is a block diagram illustrating a schematic configuration example of an electronic information device using the solid-state imaging device 1, 1 </ b> A to 1 </ b> C, 1 </ b> E, or 1 </ b> F of Embodiments 1 to 4 of the present invention as an imaging unit as Embodiment 5 of the present invention. It is.

  In FIG. 8, the electronic information device 90 according to the third embodiment performs predetermined signal processing on the imaging signals from the solid-state imaging devices 1, 1 </ b> A to 1 </ b> C, 1 </ b> E, or 1 </ b> F according to the first to fourth embodiments, and performs color images. A solid-state imaging device 91 that obtains a signal, a memory unit 92 such as a recording medium that enables data recording after a predetermined signal processing is performed on the color image signal from the solid-state imaging device 91, and the solid-state imaging device 91 A display unit 93 such as a liquid crystal display device that can display a color image signal on a display screen such as a liquid crystal display screen after performing predetermined signal processing for display, and the color image signal from the solid-state imaging device 91 for communication. After performing predetermined print signal processing for printing the color image signal from the solid-state imaging device 91 and the communication unit 94 such as a transmission / reception device that can perform communication processing after performing predetermined signal processing And an image output unit 95 such as a printer which allows printing process. The electronic information device 90 is not limited to this, but in addition to the solid-state imaging device 91, at least one of a memory unit 92, a display unit 93, a communication unit 94, and an image output unit 95 such as a printer. You may have.

  As described above, the electronic information device 90 includes, for example, a digital camera such as a digital video camera and a digital still camera, an in-vehicle camera such as a surveillance camera, a door phone camera, and an in-vehicle rear surveillance camera, and a video phone camera. An electronic device having an image input device such as an image input camera, a scanner device, a facsimile device, a camera-equipped mobile phone device, and a portable terminal device (PDA) is conceivable.

  Therefore, according to the third embodiment, based on the color image signal from the solid-state imaging device 91, it can be displayed on the display screen, or can be printed out on the paper by the image output unit 95. (Printing), communicating this as communication data in a wired or wireless manner, performing a predetermined data compression process in the memory unit 92 and storing it in a good manner, or performing various data processings satisfactorily Can do.

  As mentioned above, although this invention has been illustrated using preferable Embodiment 1-5 of this invention, this invention should not be limited and limited to this Embodiment 1-5. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge from the description of specific preferred embodiments 1 to 5 of the present invention. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  The present invention relates to a solid-state image pickup device such as a CMOS image sensor or a CCD image sensor configured by a plurality of semiconductor elements that photoelectrically convert image light from a subject and pick up an image, and an imaging unit using the solid-state image pickup device as an image input device. In the field of electronic information devices such as digital cameras such as digital video cameras and digital still cameras used in the above, image input cameras such as surveillance cameras, scanner devices, facsimile devices, television telephone devices, and mobile phone devices with cameras, A high-sensitivity solid that further suppresses reflection and absorption of incident light by providing a silicon carbide film having a high refractive index (2.65) for anti-reflection above the light receiving portion and directly above it. An image sensor can be obtained. Thus, it is possible to provide a highly sensitive solid-state imaging device that suppresses reflection and absorption at the time of incidence of light and an electronic information device equipped with such a solid-state imaging device.

DESCRIPTION OF SYMBOLS 1, 1A-1C, 1E, 1F Solid-state image sensor 2 P well layer of silicon substrate 3 Light-receiving part 3 (photodiode)
4 Insulating film 5 Wiring circuit 6 Interlayer insulating film 7 Insulating film 8, 8A to 8C, 8E, 8F Anti-reflection silicon carbide film (SiC film)
9 Flattening film 10 Color filter 11 Flattening film 12 Microlens 13, 13a Silicon nitride or silicon oxynitride film 13b Third transparent insulating film (silicon nitride film or silicon oxynitride film)
14, 14F Second transparent insulating film (silicon oxide film or silicon oxynitride film)
DESCRIPTION OF SYMBOLS 15 Metal layer for light shielding 16 Metal layer for color-mixing reduction 90 Electronic information equipment 91 Solid-state imaging device 92 Memory part 93 Display part 94 Communication part 95 Image output part

Claims (17)

  A solid-state imaging device in which a plurality of light receiving portions that photoelectrically convert incident light to image are arranged in a two-dimensional manner, and an antireflection silicon carbide film is first above each of the plurality of light receiving portions. A solid-state imaging device formed as a transparent insulating film.   2. The solid-state imaging device according to claim 1, wherein the silicon carbide film is formed to have a film thickness at which a reflectance is a minimum value of a period corresponding to the film thickness of a specific wavelength of incident light.   3. The solid-state imaging device according to claim 2, wherein the silicon carbide film has a thickness of 30 nm to 100 nm or 200 nm.   2. The solid-state imaging device according to claim 1, wherein a silicon oxide film or a silicon oxynitride film containing more oxygen than nitrogen is formed between the silicon carbide film and the semiconductor substrate and having a thickness of more than 0 and not more than 30 nm. . 2. The solid-state imaging device according to claim 1, wherein the group III impurity of the silicon carbide film is non-doped or formed at an impurity concentration of more than 0 and less than 1 × 10 ¹⁷ cm ⁻³ . 2. The solid-state imaging device according to claim 1, wherein the Group V impurities excluding Group V nitrogen of the silicon carbide film are non-doped or formed with an impurity concentration of more than 0 and less than 1 × 10 ¹⁷ cm ^−3. . 2. The solid-state imaging device according to claim 1, wherein the impurity nitrogen of the silicon carbide film is non-doped or formed at an impurity concentration of more than 0 and less than 1 × 10 ¹⁷ cm ⁻³ .   The solid-state imaging device according to claim 1, wherein a silicon nitride film or a silicon oxynitride film is formed on the silicon carbide film.   2. The solid-state imaging device according to claim 1, wherein a total film thickness of the silicon carbide film and the silicon nitride film or the silicon oxynitride film thereon is formed to a thickness of 30 nm to 100 nm or 200 nm or less. The silicon carbide film is formed, or a film formed by combining the silicon carbide film and the silicon nitride film or silicon oxynitride film thereon,
A silicon oxide film or a second transparent insulating film of silicon oxynitride having a higher oxygen content than nitrogen is formed on the formed film,
The solid-state imaging device according to claim 1, wherein a third transparent insulating film of a silicon nitride film or a silicon oxynitride film is formed on the second transparent insulating film. 11. The solid-state imaging device according to claim 10, wherein the second transparent insulating film and the third transparent insulating film are formed to have a film thickness that relaxes a stress of a semiconductor substrate and optimizes a dark current or a white spot defect.   The solid-state imaging device according to claim 11, wherein the film thickness of the second transparent insulating film is 30 nm or more and 200 nm or less.   The solid-state imaging device according to claim 11, wherein the thickness of the third transparent insulating film is not less than 30 nm and not more than 500 nm.   The silicon carbide film, the silicon carbide film and the silicon nitride film or silicon oxynitride film thereon, or the second transparent insulating film of the silicon oxide film or silicon oxynitride film, or the silicon nitride film or acid 2. The solid according to claim 1, wherein a metal layer for light shielding or color mixing reduction is formed on the third transparent insulating film of the silicon nitride film or between the second transparent insulating film and the third transparent insulating film. Image sensor.   A back-illuminated solid-state imaging device having a wiring circuit for reading signal charges from the light receiving unit on the first surface side of a semiconductor substrate and photoelectrically converting light incident from the second surface side of the semiconductor substrate. Item 2. The solid-state imaging device according to Item 1.   The solid-state imaging device according to claim 1, which is a CMOS solid-state imaging device or a CCD solid-state imaging device.   An electronic information device using the solid-state imaging device according to claim 1 as an image input device in an imaging unit.

Images