JP4779304B2 - Solid-state image sensor, camera module, and electronic device module - Google Patents

Description

The present invention relates to a solid-state imaging device in which a plurality of unit pixels that convert and output signal charges photoelectrically converted by a photoelectric conversion device are arranged , a camera module including the solid- state imaging device , and an electronic device module .

  As the solid-state imaging device, a CMOS solid-state imaging device typified by a CMOS image sensor and a CCD solid-state imaging device typified by a CCD image sensor are known. Taking a CMOS solid-state imaging device as an example, an example of the cross-sectional structure is shown in FIG.

  FIG. 9 shows an example of a conventional surface irradiation type CMOS solid-state imaging device. The CMOS solid-state imaging device 1 includes a p-type semiconductor well region 3 of a second conductivity type formed on a first conductivity type, for example, an n-type silicon semiconductor substrate 2, and pixel separation of the p-type semiconductor well region 3. In a unit pixel area partitioned by the area 10, a photodiode 5 serving as a photoelectric conversion unit and a MOS transistor group 6 including a plurality of MOS transistors are formed. The photodiode 5 is formed of an n-type semiconductor region surrounded by the pixel isolation region 3 and the p-type semiconductor well region 3. That is, it is formed by a low impurity concentration n-type semiconductor region (n− semiconductor region) 11 deep from the surface and a high impurity concentration n-type semiconductor region (n + semiconductor region) 12 on the surface side. Further, a p + accumulation layer 13 made of a p-type semiconductor region having a high impurity concentration for suppressing dark current generation is formed at the surface side interface of the n + semiconductor region 12. The photodiode 5 is configured as a so-called HAD (Hole Accumulation Diode) sensor.

  The MOS transistor group 6 includes a read transistor 7 connected to a photodiode and other MOS transistors 8. The read transistor 7 has an n + source / drain region 14 formed in the P-type semiconductor well region 3, an n + semiconductor region 12 of the photodiode 5, and gate insulation on the substrate surface between the n + source / drain region 14 and the photodiode 5. The gate electrode 18 is formed through a film. The other MOS transistor 8 includes n + source / drain regions 15 and 16 formed in the P-type semiconductor well region 3 and a gate formed on the substrate surface between the n + source / drain regions 15 and 16 via a gate insulating film. And the electrode 19. For example, when it is composed of four MOS transistors, it is composed of a read transistor, a reset transistor, an amplifier transistor and a vertical selection transistor. Furthermore, a multilayer wiring layer 25 is formed on the substrate surface via an interlayer insulating film 23. Although not shown, a color filter, an on-chip lens, and the like are also formed.

  Light incident on the photodiode 5 is irradiated from the surface side of the substrate on which the MOS transistors that perform signal charge accumulation and readout operations are formed. In such a front-illuminated CMOS solid-state imaging device 1, an antireflection film 26 is formed in order to increase the light collection efficiency on the substrate surface side photodiode 5. In the front-illuminated type CMOS solid-state imaging device 1, silicon oxide (typically four or more layers) is formed by a protective film for preventing deterioration over time such as a photodiode, a MOS transistor group, and a wiring layer, and an interlayer insulating film below the protective film. An SiO) film and a silicon nitride (SiN) film are present on the photodiode 5.

  The reason why four or more insulating films are formed on the light irradiation surface side is that a thick interlayer insulating film (silicon oxide film 23) is required in the middle because the multilayer wiring layer 25 is provided. In the illustrated example, a four-layer film of a silicon oxide (SiO) film 21, a silicon nitride (SiN) film 22, a silicon oxide (SiO) film 23, and a silicon nitride (SiN) film 24 is formed on the light irradiation surface side. .

  On the other hand, in a front-illuminated CMOS solid-state imaging device, there is a wiring layer formed of a light-shielding material. An inner lens may be formed. In the case of having an in-layer lens, five or six layers of insulating films having different refractive indexes are present on the silicon substrate.

  The CCD solid-state imaging device may also have an in-layer lens, and the same four or more layers of silicon oxide (SiO) film and silicon nitride (SiN) film are formed on the light irradiation surface side.

Patent Document 1 proposes an example of a surface irradiation type CMOS solid-state imaging device in which four or more insulating films are formed on a light irradiation surface on the surface side.
JP 2003-224249 A

By the way, when an anti-reflection film is composed of four or more layers of silicon oxide film and silicon nitride film, it has spectral characteristics with so-called ripples that rise and fall in a short period due to interference with the film of refractive index, and the sensitivity of the image sensor is lost. is doing. FIG. 5 is a graph showing the wavelength dependence of the photoelectric conversion rate due to the difference in the film configuration of the antireflection film on the light irradiation surface. The horizontal axis in FIG. 5 represents the wavelength of the irradiation light. The vertical axis is proportional to the product of the light transmittance and the light absorptance in silicon (transmittance × Si absorptance), that is, the photoelectric conversion efficiency, and corresponds to the sensitivity.
Curve C in FIG. 5 shows a plasma silicon nitride (PSiN) film having a thickness of 500 nm, a silicon oxide (SiO) film having a thickness of 5000 nm, a silicon nitride (SiN) film having a thickness of 50 nm, and a silicon oxide having a thickness of 15 nm. The spectral characteristics of an antireflection film having a four-layer film structure in which (SiO) films are sequentially deposited from below are shown. As can be seen from the curve C, the spectral characteristic of the antireflection film by the four-layer film is a spectral characteristic with a ripple that rises and falls in a short cycle, and its integrated value (integrated value of photoelectric conversion efficiency) becomes sensitivity. If you look at it, it will shift downward.
Curve B in FIG. 5 shows three layers in which a plasma silicon nitride (PSiN) film having a thickness of 500 nm, a silicon nitride (SiN) film having a thickness of 50 nm, and a silicon oxide (SiO) film having a thickness of 15 nm are sequentially deposited from below. It is a spectral characteristic of the antireflection film of a film structure. This is a spectral characteristic that rises and falls with a coarser period than the antireflection film of the four-layer film.

  Further, in the case of a surface irradiation type solid-state imaging device, in the case of a solid-state imaging device in which an in-layer lens is formed in order to improve sensitivity, five or six layers of films having different refractive indexes exist on the silicon substrate. The sensitivity loss becomes more prominent. However, when an intralayer lens is formed, the condensing efficiency by the intralayer lens is more effective than the effect of the antireflection film by the multilayer film. As the structure of the antireflection film, the sensitivity of the image sensor is lowered as the number of layers of the film increases.

In view of the above, the present invention provides a solid-state imaging device that improves the antireflection efficiency and enables higher sensitivity, and a camera module and an electronic device module including the solid-state imaging device.
The invention, together, which provides shading, the solid-state imaging device having a reduced optical color mixing to adjacent pixel, the solid-state imaging device made it possible to achieve the small sensor and a lens module, a camera module and an electronics module It is.

The solid-state imaging device according to the present invention includes a plurality of pixels each including a photoelectric conversion unit and a plurality of transistors. The plurality of transistors are formed on the surface side of the semiconductor substrate. The photoelectric conversion part is formed extending from the front surface side to the back surface side of the semiconductor substrate. An antireflection film is formed on the back surface, which is the light irradiation surface of the semiconductor substrate, by a two-layer film having a refractive index different from that of the semiconductor substrate and deposited in order from the light irradiation surface to a film having a low refractive index. In addition, a color filter or an on-chip lens is formed in contact with the antireflection film . The solid-state imaging device is configured as a backside illumination type.

The camera module according to the present invention includes a solid-state imaging device and an optical lens system. The solid-state imaging device has a plurality of pixels including a photoelectric conversion unit and a plurality of transistors. The plurality of transistors are formed on the surface side of the semiconductor substrate. The photoelectric conversion part is formed extending from the front surface side to the back surface side of the semiconductor substrate. An antireflection film is formed on the back surface, which is the light irradiation surface of the semiconductor substrate, by a two-layer film having a refractive index different from that of the semiconductor substrate and deposited in order from the light irradiation surface to a film having a low refractive index. In addition, a color filter or an on-chip lens is formed in contact with the antireflection film . The solid-state imaging device is configured as a backside illumination type.

The electronic apparatus module according to the present invention includes a solid-state imaging device, an optical lens system, and signal processing means. The solid-state imaging device has a plurality of pixels including a photoelectric conversion unit and a plurality of transistors. The plurality of transistors are formed on the surface side of the semiconductor substrate. The photoelectric conversion part is formed extending from the front surface side to the back surface side of the semiconductor substrate. An antireflection film is formed on the back surface, which is the light irradiation surface of the semiconductor substrate, by a two-layer film having a refractive index different from that of the semiconductor substrate and deposited in order from the light irradiation surface to a film having a low refractive index. In addition, a color filter or an on-chip lens is formed in contact with the antireflection film . The solid-state imaging device is configured as a backside illumination type.

The above-described solid-state imaging device according to the present invention is configured as a back-illuminated type, and is deposited on the back surface serving as the light irradiation surface of the semiconductor substrate in the order of a film having a refractive index different from that of the semiconductor substrate and having a low refractive index from the light irradiation surface. By forming an antireflection film by the two-layered film and forming a color filter or an on-chip lens on the antireflection film in contact with the antireflection film, the antireflection efficiency is improved and the photoelectric conversion efficiency is improved. To do. In addition, since the on-chip lens and the semiconductor substrate surface that performs photoelectric conversion are close to each other, shading due to a difference in incident angle in the screen and optical color mixture to adjacent pixels are reduced.

According to the solid-state imaging device of the present invention, two layers are deposited on the light irradiation surface on the back surface of the back-illuminated solid-state imaging device in the order of a film having a refractive index different from that of the semiconductor substrate and having a low refractive index from the light irradiation surface. By forming an antireflection film on the film and forming a color filter or an on-chip lens on the antireflection film in contact with the antireflection film, the photoelectric conversion efficiency is improved, and the back-illuminated solid-state imaging device Sensitivity can be further improved.

In addition, since the on-chip lens and the semiconductor substrate surface that performs photoelectric conversion are close to each other, shading caused by a difference in incident angle in the screen and optical color mixing to adjacent pixels can be reduced. Further, a shading, if allowed optical color mixing to equivalent conventional front-illuminated solid-state imaging device, it is possible to increase the angle of incidence around the imaging region, that it is possible to shorten the exit pupil distance, It is possible to realize a small module (for example, a camera module, an electronic module, etc.) configured as a single device by integrating a solid-state imaging device and a lens. Furthermore, when the antireflection film is a two-layer film, the number of steps can be reduced, and the cost can be reduced.

According to the camera module of the present invention, by providing the solid-state imaging device, it is possible to improve sensitivity, reduce shading and optical color mixing to adjacent pixels, and realize a more compact camera module.
According to the electronic device module of the present invention, by providing the solid-state imaging device, sensitivity can be improved, shading and optical color mixing to adjacent pixels can be reduced, and a more compact electronic device module can be realized. .

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a pixel portion showing an embodiment in which a solid-state imaging device according to the present invention is applied to a back-illuminated CMOS solid-state imaging device. FIG. 2 is a detailed sectional view of the one pixel.
As shown in FIG. 1, the backside illumination type CMOS solid-state imaging device 31 according to the present embodiment forms a pixel isolation region 33 including a second conductivity type semiconductor region on a first conductivity type silicon semiconductor substrate 32. In order to read out the photodiode 34 serving as a photoelectric conversion unit and the signal charge accumulated in the photodiode 34 so that each pixel region partitioned by the pixel isolation region 33 is surrounded by the second conductivity type semiconductor region. The required number of MOS transistors 35 are formed. The pixel isolation region 33 is formed in the depth direction so as to reach the back surface from the front surface of the substrate 32. The MOS transistor 35 is formed on the front surface side of the substrate 32, and the photodiode 34 is formed so as to extend partially on the back surface side of the substrate 32 so as to extend below the MOS transistor 35.

  A gate electrode 37 of the MOS transistor 35 is formed on the surface of the substrate 32, a multilayer wiring layer 39 is formed thereon via an interlayer insulating film 38, and a support substrate 40 is further formed on the interlayer insulating film 38. Is formed. As the support substrate 40, for example, a silicon substrate can be used. On the other hand, an on-chip color filter 42 is formed on the back surface of the semiconductor substrate 32 via an antireflection film 41 according to the present invention described later, and an on-chip lens 43 is formed on the color filter 42 so as to correspond to each pixel. Is done. In the CMOS solid-state imaging device 31, light L is irradiated to the photodiode 34 from the back surface of the substrate through the on-chip lens 43.

  An example of a specific configuration of the unit pixel of the solid-state image sensor 31 is shown in FIG. In this example, a pixel isolation region 33 made of a p-type semiconductor region of the second conductivity type is formed so as to partition each pixel region 101 on an n-type silicon semiconductor substrate 32 of the first conductivity type. The pixel isolation region 33 is formed of a relatively low concentration p-type semiconductor region. A p-type semiconductor well region 51 is formed on the surface of the n-type semiconductor substrate 32 in the pixel region 101 so as to connect to the p-type pixel isolation region 33 and partially extend into the pixel region 101. The photodiode 34 serving as a photoelectric conversion unit is formed of an n-type semiconductor substrate 32 surrounded by a p-type pixel isolation region 33 and a p-type semiconductor well region 51. That is, the photodiode 34 is formed by the n semiconductor region 32A and the high impurity concentration n + semiconductor region 32B on the surface side thereof. A p + accumulation layer 53 made of a high impurity concentration p-type semiconductor region for suppressing dark current generation is formed at the interface on the surface side of the n + semiconductor region 32B. Further, in common to each pixel region, p + accumulation comprising a high impurity concentration p-type semiconductor region for suppressing dark current generation on the back surface of the n-type semiconductor substrate 32, that is, the interface on the back surface side of the n semiconductor region 32A. Layer 54 is formed.

  The photodiode 34 is configured as a so-called HAD sensor because it has p + accumulation layers 53 and 54 on the front surface of the n + semiconductor region 32B and the back surface of the n semiconductor region 32A. Further, since the n semiconductor region 32A extends below the p-type semiconductor well region 51, the photodiode 34 is formed in a large area so as to cover the entire pixel region.

  On the other hand, the MOS transistor 35 is formed in the p-type semiconductor well region 51. That is, for example, when one pixel is composed of one photodiode and four MOS transistors, the MOS transistor 35 includes a read transistor, a reset transistor, an amplifier transistor, and a vertical selection transistor. In FIG. 2, one n + source / drain region 61 is formed in the p-type semiconductor well region 51 in the vicinity of the photodiode 34, and the one n + source / drain region 61 and the other source / drain region serve as the photodiode. A gate electrode 37 is formed on the p-type semiconductor well region 51 between the n + semiconductor regions 52 of 34 via a gate insulating film to form the read transistor Tr1.

Further, corresponding n + source / drain regions 62 and 63 are formed in the other part of the p-type semiconductor well region 51, and a gate insulating film is formed on the p-type semiconductor well region 51 between the n + source / drain regions 62 and 63. The gate electrode 37 is formed through the other transistors, and other MOS transistors, that is, the reset transistor Tr2, the amplifier transistor Tr3, and the vertical selection transistor Tr4 are formed.
A multilayer wiring layer 39 is formed on the surface of the semiconductor substrate via an interlayer insulating film 38 made of, for example, a silicon oxide film, and a support substrate 40 made of, for example, a silicon substrate is bonded onto the interlayer insulating film 38. An antireflection film 41 of the present invention is formed on the light irradiation surface 56 on the back surface of the semiconductor substrate, and an on-chip lens 43 is formed on the antireflection film 41 via an on-chip color filter 42.

  In the present embodiment, as particularly shown in FIG. 3, the antireflection film 41 on the light irradiation surface 56 on the back surface side of the substrate is reflected by two layers of films 66 and 67 having a refractive index different from that of the silicon substrate 32. It is formed by the prevention film 411. In FIG. 3, in order to clarify the configuration of the antireflection film 411, the portions other than the antireflection film 411 are the same as those in FIGS. 1 and 2, so that the photodiode, the MOS transistor, the wiring layer, and the like are omitted. The two-layer antireflection film 411 is formed of a two-layer film 66 or 67 selected from a silicon oxide (SiO) film, a silicon nitride (SiN) film, a silicon oxynitride (SiON) film, and polycrystalline silicon. be able to. FIG. 4 shows a configuration example of the antireflection film 411.

In FIG. 4A, a silicon oxide (SiO) film 66 and a silicon nitride (SiN) film 67 are sequentially deposited on the light irradiation surface 56 on the back surface of the silicon substrate to form a two-layer antireflection film 411.
In FIG. 4B, a silicon oxide (SiO) film 66 and a silicon oxynitride (SiON) film 67 are sequentially deposited on the light irradiation surface 56 on the back surface of the silicon substrate to form a two-layer antireflection film 411.
In FIG. 4C, a silicon oxynitride (SiON) film 66 and a silicon nitride (SiN) film 67 are sequentially deposited on the light irradiation surface 56 on the back surface of the silicon substrate to form a two-layer antireflection film 411.
The refractive index of the silicon oxynitride film varies with the composition ratio of nitrogen N, and the refractive index increases as the composition ratio of nitrogen N increases. The films 66 and 67 are deposited in order from the light irradiation surface 56 to a film having a small refractive index.

  As the antireflection film 411, a combination of a silicon oxide (SiO) film 66 and a silicon nitride (SiN) film 67 is preferable. At this time, the film thickness of the silicon oxide (SiO) film 66 is preferably 25 nm or less (not including 0). The thickness of the silicon oxide film can be about 1 nm, and can be as thin as possible. The thickness of the silicon nitride film 67 is preferably in the range of 40 nm to 60 nm. If the thickness of the silicon oxide film 66 is 25 nm or less, the spectral characteristics according to the present invention indicated by the curve A in FIG. 5 described later are higher than the average spectral characteristics of the four-layer film (see the curve C). The photoelectric conversion efficiency can be improved. When the thickness of the silicon nitride film 67 is in the range of 40 nm to 60 nm, the photoelectric conversion efficiency can be improved for the same reason as described above.

  In FIG. 5, a curve A is a spectral characteristic showing the wavelength dependence of the photoelectric conversion efficiency of the antireflection film 411 by the two-layer film of the silicon oxide film 66 and the silicon nitride film 67 according to the present embodiment. This curve A is a characteristic when the thickness of the silicon oxide film 66 is about 15 nm and the thickness of the silicon nitride film 67 is about 50 nm. The photoelectric conversion efficiency is improved and the sensitivity of the imaging device is improved as compared with the four-layer film (see curve C) and the three-layer film (curve B).

According to the backside illuminating type CMOS solid-state imaging device 31 according to the present embodiment, the reflection of the antireflection film 411 by the two-layer film on the light irradiation surface on the backside of the substrate, preferably the reflection of the two-layer film of the silicon oxide film and the silicon nitride film. By forming the prevention film, the antireflection efficiency of incident light can be improved and the sensitivity of the image sensor can be improved.
The antireflection film 411 formed of the two-layer film is a back-illuminated CMOS solid-state imaging device, and thus can be formed without being restricted by a multilayer wiring layer.
In the solid-state imaging device 31 of the present embodiment, since the photodiode 34 facing the back surface of the substrate is formed in the entire pixel region, the opening of the photodiode 34 becomes 100%, and further improvement in photoelectric conversion efficiency is obtained. A highly sensitive solid-state imaging device can be obtained.

In addition, since the antireflection film 411 of the two-layer film is provided, the on-chip lens 43 that is the uppermost layer of the light irradiation surface and the silicon surface that performs photoelectric conversion approach each other, thereby causing shading caused by a difference in incident angle in the imaging surface. , Optical color mixing to adjacent pixels can be reduced.
In addition, if the shading and optical color mixing are allowed to the same extent as the conventional surface irradiation type CMOS solid-state imaging device, the incident angle around the imaging region can be increased, and the so-called exit pupil distance can be shortened, It is possible to realize a small module (for example, a camera module, an electronic module, etc.) configured as a single device by integrating a solid-state imaging device and a lens. Furthermore, by providing the antireflection film 411 with a two-layer film, it is possible to reduce the manufacturing process and the cost by reducing the process.

  As the antireflection film 41 according to the present invention shown in FIG. 1, a two-layer antireflection film 411 is configured in FIG. 4. In addition, as shown in FIG. 6, an antireflection film 422 using a single layer film is configured. can do. In this case, the single-layer antireflection film 412 is formed so that the refractive index varies stepwise in the film thickness direction. For example, a silicon oxynitride (SiON) film can be used, and the nitrogen composition ratio can be changed in the film thickness direction to form a single-layer antireflection film.

The antireflection films 41 [411 to 413] and 422 according to the present invention can be applied to a back-illuminated CCD solid-state imaging device. Although not shown, the back-illuminated CCD solid-state imaging device of this example has a charge storage region with a high impurity concentration in a photoelectric conversion unit (photodiode) on the surface side of a semiconductor substrate and a signal charge from the photoelectric conversion unit. A vertical transfer register for reading is formed, and an accumulation layer having a high impurity concentration for suppressing dark current generation is formed at the interface of the photoelectric conversion portion facing the back side of the semiconductor substrate. An on-chip lens is formed on this backside accumulation layer via a color filter. Further, a reinforcing support substrate is bonded to the front side.
In this example , for example, the two-layer antireflection film 411 or the one-layer antireflection film according to the present invention described above is applied to the surface of the accumulation layer on the back surface side, that is, the light irradiation surface 87 on the back surface side. 422 is formed.

Also in the back-illuminated CCD solid-state image sensor according to this example , the antireflection efficiency of incident light can be improved and the sensitivity of the image sensor can be improved, as in the above-described back-illuminated CMOS solid-state image sensor. Further, since the photoelectric conversion portion (photodiode) facing the back surface of the substrate can be formed in the entire pixel region, the opening of the photodiode 74 becomes 100%, and further improvement in photoelectric conversion efficiency is obtained, and a highly sensitive solid state is obtained. An image sensor is obtained.
By approaching the on-chip lens, which is the uppermost layer of the light irradiation surface, and the silicon surface to be photoelectrically converted, shading caused by the difference in the incident angle in the imaging surface and optical color mixing to adjacent pixels can be reduced. .
In addition, if the shading and optical color mixing are allowed to the same extent as the conventional surface irradiation type CMOS solid-state imaging device, the incident angle around the imaging region can be increased, and the so-called exit pupil distance can be shortened, It is possible to realize a small module (for example, a camera module, an electronic module, etc.) configured as a single device by integrating a solid-state imaging device and a lens.

  In the above example, the antireflection film 41 according to the present invention is applied to a back-illuminated solid-state image sensor. However, it can be applied to a front-illuminated CMOS solid-state image sensor or a CCD solid-state image sensor. When applied to a front-illuminated CMOS solid-state imaging device or a CCD solid-state imaging device, for example, the wiring interlayer insulating film immediately above the silicon can be removed, and only the antireflection film of the present invention can be formed here. Or it can also be set as the structure of an anti-reflective film, an on-chip color filter, and an on-chip lens.

The present invention can constitute an imaging camera and various modules by incorporating the above-described solid-state imaging device. FIG. 7 shows an embodiment of the back-illuminated CMOS solid-state imaging device 31 and the optical lens system 85 described above, in which a two-layer film or a single-layer antireflection film 41 is formed on the light irradiation surface on the back surface. . The color filter can be arranged between the antireflection film 41 and the on-chip lens 43 (or 89), or on the optical lens system 85 side as shown in FIG. It can also be arranged on the side opposite to the solid-state imaging device or on the opposite side.

FIG. 8 shows a schematic configuration showing an embodiment of an electronic device module and a camera module according to the present invention. The module configuration of FIG. 8 can be applied to both an electronic device module and a camera module. Module 110 of the present embodiment, one of the back surface radiation type solid-state imaging device 31 of the above-described embodiment, the optical lens system 111, input-output unit 112 signal processing apparatus (Digital Signal Processors) 113, an optical lens system control A central processing unit (CPU) 114 is integrated into one to form a module. In addition, as the electronic device module or the camera module 115, for example, a module can be formed by only the back-illuminated solid-state imaging device 31 or 71, the optical lens system 111, and the input / output unit 112. Further, for example, a module 116 including a back-illuminated solid-state imaging device 31 or 71, an optical lens system 111, an input / output unit 112, and a signal processing device (Digital Signal Processors) 113 can be configured.

  According to the camera module and the electronic device module according to the present embodiment, the antireflection efficiency of incident light on the solid-state image sensor can be improved, and the sensitivity of the solid-state image sensor in the module can be improved. In addition, shading caused by the difference in incident angle in the imaging surface and optical color mixing to adjacent pixels are reduced. If shading and optical color mixing are allowed to the same extent as a conventional surface irradiation type solid-state imaging device, the exit pupil distance can be shortened, and a smaller module can be realized.

  In addition, even when the solid-state imaging device of the present invention, particularly the back-illuminated solid-state imaging device, is applied to an imaging camera, the antireflection efficiency of incident light to the solid-state imaging device is improved and the sensitivity of the imaging camera is improved. Can do. In addition, shading caused by the difference in incident angle in the imaging surface and optical color mixing to adjacent pixels are reduced. If shading and optical color mixing are allowed to the same extent as those of a conventional surface irradiation type solid-state imaging device, the exit pupil distance can be shortened, and a more compact imaging camera can be realized.

It is a schematic block diagram which shows embodiment of the backside illumination type CMOS solid-state image sensor concerning this invention. It is sectional drawing which shows an example of the cross-sectional structure of 1 pixel in the CMOS solid-state image sensor of embodiment shown in FIG. It is a schematic diagram which shows embodiment of the anti-reflective film in the CMOS solid-state image sensor of embodiment shown in FIG. AC is a cross-sectional view showing an example of a two-layer antireflection film according to the present invention. It is a graph which shows the wavelength dependence of the photoelectric conversion rate by the difference in the film | membrane structure on a light irradiation surface. It is a block diagram which shows other embodiment of the antireflection film concerning this invention. It is a schematic block diagram which shows the other example of arrangement | positioning of a color filter at the time of applying this invention to the module provided with the solid-state image sensor and the optical lens system, or an imaging camera. It is a schematic block diagram which shows embodiment of the module which concerns on this invention. It is a block diagram of the conventional surface irradiation type CMOS solid-state image sensor.

  31..Back-illuminated CMOS solid-state imaging device, 32..Semiconductor substrate, 32A..n semiconductor region, 33..Pixel isolation region, 34..Photodiode, 35..MOS transistor, Tr1..readout transistor, 37 .... Gate electrode, 38 ... Interlayer insulation film, 39 ... Multi-layer wiring layer, 40 ... Support substrate, 41 [411 to 413], 422 ... Antireflection film, 42 ... Color filter, 43 ... On-chip lens, 51 ·· p-type semiconductor well region, 52 ·· n + semiconductor region, 53, 54 ·· p + accumulation layer, 56 ·· Light irradiation surface, 66, 67 ·· Insulating film

Claims (12)

Having a plurality of pixels consisting of a photoelectric conversion unit and a plurality of transistors,
The plurality of transistors are formed on a surface side of a semiconductor substrate,
The photoelectric conversion portion is formed to extend from the front surface side to the back surface side of the semiconductor substrate,
On the back surface, which is the light irradiation surface of the semiconductor substrate, an antireflection film is formed by a two-layer film that has a refractive index different from that of the semiconductor substrate and is deposited in the order of a film having a small refractive index from the light irradiation surface,
On the antireflection film, a color filter or an on-chip lens is formed in contact with the antireflection film ,
A solid-state imaging device characterized by being configured as a back-illuminated type. The solid-state imaging device according to claim 1, wherein the antireflection film is formed of a two-layer film in which a silicon oxide film and a silicon oxynitride film are sequentially deposited from the light irradiation surface. The solid-state imaging device according to claim 1, wherein the antireflection film is formed of a two-layer film in which a silicon oxynitride film and a silicon nitride film are sequentially deposited from the light irradiation surface. The antireflection film is formed of a two-layer film in which a silicon oxide film and a silicon nitride film are sequentially deposited from the light irradiation surface,
2. The solid-state imaging device according to claim 1, wherein the silicon oxide film has a thickness of 25 nm or less (not including 0), and the silicon nitride film has a thickness of 40 nm to 60 nm. It has a solid-state image sensor and an optical lens system,
The solid-state imaging device is
Having a plurality of pixels consisting of a photoelectric conversion unit and a plurality of transistors,
The plurality of transistors are formed on a surface side of a semiconductor substrate,
The photoelectric conversion portion is formed to extend from the front surface side to the back surface side of the semiconductor substrate,
On the back surface, which is the light irradiation surface of the semiconductor substrate, an antireflection film is formed by a two-layer film that has a refractive index different from that of the semiconductor substrate and is deposited in the order of a film having a small refractive index from the light irradiation surface,
On the antireflection film, a color filter or an on-chip lens is formed in contact with the antireflection film ,
A camera module characterized by being configured as a back-illuminated type. The camera module according to claim 5, wherein the antireflection film is formed of a two-layer film in which a silicon oxide film and a silicon oxynitride film are sequentially deposited from the light irradiation surface. The camera module according to claim 5, wherein the antireflection film is formed of a two-layer film in which a silicon oxynitride film and a silicon nitride film are sequentially deposited from the light irradiation surface. The antireflection film is formed of a two-layer film in which a silicon oxide film and a silicon nitride film are sequentially deposited from the light irradiation surface,
The camera module according to claim 5, wherein the silicon oxide film has a thickness of 25 nm or less (excluding 0), and the silicon nitride film has a thickness of 40 nm to 60 nm. A solid-state imaging device, an optical lens system, and signal processing means;
The solid-state imaging device is
Having a plurality of pixels consisting of a photoelectric conversion unit and a plurality of transistors,
The plurality of transistors are formed on a surface side of a semiconductor substrate,
The photoelectric conversion portion is formed to extend from the front surface side to the back surface side of the semiconductor substrate,
On the back surface, which is the light irradiation surface of the semiconductor substrate, an antireflection film is formed by a two-layer film that has a refractive index different from that of the semiconductor substrate and is deposited in the order of a film having a small refractive index from the light irradiation surface,
On the antireflection film, a color filter or an on-chip lens is formed in contact with the antireflection film ,
An electronic device module characterized by being configured as a back-illuminated type. The electronic device module according to claim 9, wherein the antireflection film is formed of a two-layer film in which a silicon oxide film and a silicon oxynitride film are sequentially deposited from the light irradiation surface. The electronic device module according to claim 9, wherein the antireflection film is formed of a two-layer film in which a silicon oxynitride film and a silicon nitride film are sequentially deposited from the light irradiation surface. The antireflection film is formed of a two-layer film in which a silicon oxide film and a silicon nitride film are sequentially deposited from the light irradiation surface,
10. The electronic device module according to claim 9, wherein the thickness of the silicon oxide film is 25 nm or less (not including 0), and the thickness of the silicon nitride film is 40 nm to 60 nm.

Images