JP2007242877A - Solid-state imaging element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state imaging element capable of receiving and detecting a visible light and an infrared ray without using a large-scale optical system and a complicated calculation processing. <P>SOLUTION: In the solid-state imaging element, color filters 16 and an on-chip lens 18 for condensing an incident light are each formed corresponding to sensors 12 of each pixel on the upper part of the sensors 12 for performing photoelectric conversion, the color filter 16 is not formed on some pixels in the pixel region, and an infrared ray cut film 21 not transmitting an infrared ray but transmitting a visible light is formed on the upper part of the on-chip lens 18 in the pixel of the pixel region in which the color filter 16 is formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device capable of receiving and detecting not only visible light but also infrared light.

In a solid-state imaging device, as the number of pixels increases, the pixel size is reduced, and the area of the photodiode (PD) per pixel decreases.
When the area of the photodiode is reduced, the amount of light reaching the photoelectric conversion unit of the photodiode is also reduced, so that sensitivity is lowered.

  Since the sensitivity is reduced in this way, S / N is reduced unless noise countermeasures are taken.

  In order to improve this S / N, there has been proposed a method for producing an image using not only visible light that has been used conventionally but also infrared light.

As one configuration, a configuration has been proposed that uses the difference in absorption coefficient in the depth direction of a semiconductor depending on the wavelength band of incident light (see, for example, Patent Document 1).
As another configuration, a wavelength separation optical system such as a wavelength separation mirror or prism is used as an input optical system, and a multi-plate type configuration in which visible light and infrared light are received by individual imaging elements, respectively. It has been proposed (see, for example, Patent Documents 2 to 4).
As another configuration, there has been proposed a configuration in which a visible wavelength light and an infrared light are received by the same image sensor using a rotary wavelength resolving optical system as an input optical system (for example, Patent Document 5). reference). Specifically, for example, when an infrared light cut filter is inserted by inserting and extracting an infrared light cut filter using a rotation mechanism, the effects of near infrared light and infrared light are inserted. When an infrared light color image without an infrared light is obtained and an infrared light cut filter is extracted, an image obtained by adding the light intensities of visible light and near infrared light can be obtained.
As another configuration, a configuration has been proposed in which visible light and infrared light are received by the same imaging device by using a diaphragm optical system having a wavelength resolving function in the input optical system (for example, a patent) Reference 6).

However, in the configuration described in Patent Document 1, the layer that detects blue light is absorbed to some extent when red light or green light passes through, so that the light is detected as blue light. For this reason, even if there is no blue signal, a false signal is generated at a blue pixel when a green or red signal is input. Due to this false signal, sufficient color reproducibility cannot be obtained.
Also, in order to achieve color reproducibility, it is necessary to correct the false signal by signal processing, and a circuit for performing this signal processing calculation is required, so the circuit configuration is complicated and large-scale. become.
Furthermore, in order to receive only infrared light, or visible light and infrared light as signals and take an image, an infrared cut filter used in a normal solid-state image sensor is removed, or an infrared cut filter is cut. It is necessary to lower the rate. However, if it does in this way, infrared light will mix with visible light and will inject into a sensor part, and the hue of the image of visible light will differ from the original thing.

In addition, the configurations described in Patent Documents 2 to 4 use a wavelength resolving optical system such as a wavelength separation mirror or prism, and therefore the input optical system becomes large. For this reason, an imaging apparatus provided with a solid-state imaging device becomes complicated or large.
Similarly, the configuration described in Patent Document 5 requires an infrared light cut filter insertion / extraction mechanism, which increases the size of the imaging device.
Furthermore, the operation of inserting / extracting the infrared light cut filter cannot be performed automatically.

Further, the configuration described in Patent Document 6 uses a diaphragm optical system having a wavelength resolving function, so that the size of the image pickup apparatus is increased.
Furthermore, although both an infrared image and a visible light image can be obtained simultaneously, the output image is a composite image of the visible light image and the infrared image, and only the visible light image or only the infrared image is obtained. Cannot be output individually.

  Therefore, as another configuration for the above-described problem, four types of color filters having different filter characteristics are regularly arranged in each pixel of the image sensor having sensitivity to visible light and infrared light. A configuration has been proposed in which a visible light color image and a near-infrared light image are independently obtained by performing matrix calculation on the output of each pixel provided with four types of color filters (see, for example, Patent Document 7). .

With such a configuration, wavelength separation is performed by arranging four types of color filters, so that the problem that the input optical system becomes large does not occur.
In addition, a visible light color image and a near-infrared light image are obtained independently by performing a matrix operation on the output of each pixel in which four types of color filters having different filter characteristics are arranged. Images can be output individually and simultaneously.

JP 2004-103964 A Japanese Patent Laid-Open No. 10-210486 JP 2002-369049 A JP-A-6-121325 JP-A-9-166493 JP-A-9-130678 JP 2002-142228 A

  However, in the configuration described in Patent Document 7, calculation processing with the infrared light component is required even when a visible light image is obtained, so that the calculation processing as a whole is complicated.

  In order to solve the above-described problems, the present invention provides a solid-state imaging device capable of receiving and detecting both visible light and infrared light without using a large-scale optical system or complicated arithmetic processing. It is to provide.

In the solid-state imaging device of the present invention, a color filter and an on-chip lens that collects incident light are respectively formed above the sensor unit that performs photoelectric conversion, corresponding to the sensor unit of each pixel,
In some of the pixel areas, a color filter is formed, and an infrared light cut film that transmits visible light but does not transmit infrared light is formed above the on-chip lens. It is what.

According to the configuration of the solid-state imaging device of the present invention described above, a color filter is formed in some of the pixels in the pixel area, and visible light is transmitted above the on-chip lens but is red. Since the infrared light cut film that does not transmit external light is formed, only visible light can be received and detected in this pixel. Thereby, a visible light image can be obtained by using an image signal obtained from the pixel on which the infrared light cut film is formed.
On the other hand, since the infrared light cut film is not formed in the remaining pixels in the pixel region, visible light and infrared light can be received and detected in the remaining pixels.
In addition, by calculating an image signal obtained from a pixel on which no infrared light cut film is formed and an image signal obtained from a pixel on which an infrared light cut film is formed, an infrared light image is obtained. Obtainable.

  Furthermore, since the infrared light cut film is formed above the on-chip lens that collects incident light, even if an infrared light cut film is provided, the total thickness from the sensor section to the on-chip lens increases. There is nothing to do.

According to the present invention described above, a visible light image can be obtained using an image signal obtained from a pixel on which an infrared light cut film is formed. A visible light image can be obtained by the same arithmetic processing as that of the solid-state imaging device that receives and detects only visible light.
As a result, an arithmetic circuit for performing complicated arithmetic processing is not required, so that the circuit configuration is not complicated.
In addition, depending on the presence or absence of a color filter and an infrared light cut film, a pixel that receives infrared light and a pixel that does not receive infrared light (does not receive infrared light) can be distributed. Even without providing, it becomes possible to detect and detect both visible light and infrared light.

  Furthermore, even if an infrared light cut film is provided, the total thickness from the sensor part to the on-chip lens does not increase, so problems due to the increase in total thickness, such as sensitivity reduction, color mixing phenomenon, shading, etc. An increase in the number can be avoided.

FIG. 1 shows a schematic configuration diagram (cross-sectional view) of a solid-state imaging device according to an embodiment of the present invention.
In this embodiment, the present invention is applied to a CMOS solid-state imaging device.

In this solid-state imaging device, a sensor unit 12 that performs photoelectric conversion is formed on the surface side of the silicon substrate 11.
Although not shown, the sensor unit 12 is formed of a first conductivity type, for example, an n-type semiconductor region, and a photodiode PD is configured by a second conductivity type, for example, a p-type semiconductor region formed on the silicon substrate 11.
Although not shown, between the sensor portions 12 of each pixel, for example, a second conductivity type (p-type) element isolation region is formed, so that adjacent pixels are separated.

A wiring layer 13 is provided above the silicon substrate 11 via an insulating layer 14. In FIG. 1, three wiring layers 13 are formed.
A planarizing film 15 is formed on the insulating layer 14 above the wiring layer 13, and a color filter 16 is formed on the planarizing film 15.

The color filter 16 is provided in every other two pixels among the four pixels shown in FIG.
The left color filter 16 in the figure is a red R color filter, and the right color filter 16 in the figure is a blue B color filter.

The color filter 16 is covered with an insulating layer 17, and an on-chip lens 18 is further formed on the insulating layer 17.
The on-chip lens 18 has a curved surface whose surface is convex upward corresponding to each pixel. Thereby, the light incident on the on-chip lens 18 can be condensed and guided to the sensor unit 12.

In the present embodiment, in particular, an infrared light cut film 21 is formed on the on-chip lens 18.
This infrared light cut film 21 has a characteristic of transmitting visible light and cutting infrared light, and does not transmit infrared light at all or hardly transmits it. Thereby, it can suppress that infrared light injects into the sensor part 12 below the infrared light cut film 21.
The infrared light cut film 21 is formed in a pixel provided with the color filter 16 among many pixels, and is not formed in a pixel not provided with the color filter 16.

The arrangement of the color filter 16 and the infrared light cut film 21 in each pixel is shown in the plan views of FIGS. 2A and 2B, respectively.
As shown in FIG. 2A, the color filter 16 is periodically arranged with 8 pixels of 2 vertical pixels × 4 horizontal pixels as a repeating unit. In the pixels in the first row and the third row (odd row) from the top, the red R color filter 16 and the blue B color filter 16 are arranged every other pixel from the left. That is, the cross-sectional view shown in FIG. 1 shows a cross-sectional view of this odd-numbered row. In the pixels in the second and fourth rows (even-numbered rows) from the top, the green G color filter 16 is arranged every other pixel from the left. In each row and column of pixels, the color filters 16 are arranged every other pixel. Further, in the pixels of each row and each column, there is a pixel in which the color filter 16 is not formed every other pixel.
As shown by hatching in FIG. 2B, the infrared light cut films 21 are arranged at every other pixel in the pixels of each row and each column, that is, arranged at the pixel where the color filter 16 was arranged. ing. On the other hand, the infrared light cut film 21 is not provided in the pixel in which the color filter 16 is not formed.

By being configured in this manner, in the pixel in which the color filter 16 is not provided, since the infrared light cut film 21 is not provided, both visible light and infrared light can be received and detected.
On the other hand, in the pixel provided with the color filter 16, since the infrared light is cut by the infrared light cut film 21, only visible light can be received and detected. Thereby, deterioration of color reproducibility due to the incidence of infrared light on normal color pixels can be avoided.

  In addition, the arrangement pattern of the color filter of each color and the pixel not forming the color filter is not limited to the arrangement shown in FIG. 2A, and other arrangements are possible.

Moreover, in this Embodiment, the infrared-light cut film 21 is comprised from the multilayer film which laminated | stacked the several film from which refractive index differs.
Thereby, the reflected light in each layer of the multilayer film can be interfered and reflected upward without transmitting infrared light downward.
The material and film thickness of each layer constituting the multilayer film of the infrared light cut film 21 can be arbitrarily set as long as infrared light can be cut.

Examples of materials used for the multilayer film of the infrared light cut film 21 include SiO (silicon oxide such as SiO ₂ ), SiN (silicon nitride such as Si ₃ N ₄ ), Si, NbO, TiO, TaO, NbO and other dielectric materials generally used for optical films made of a dielectric multilayer film can be used. It is not limited to these materials, and other materials can be used as long as they are materials that transmit visible light.
A plurality of materials having different refractive indexes are selected from these various materials, and a multilayer film is formed by laminating films of the respective materials. Preferably, the materials are combined so that the refractive index difference between the respective films becomes large.
Examples of combinations of two materials having different refractive index differences include SiO / SiN, Si / NbO, Si / TiO, Si / TaO, SiO / NbO, SiO / TiO, and SiO / TaO.

  In addition, it is possible to periodically and periodically laminate the films by fixing the thicknesses of the respective films.

FIG. 3 shows a cross-sectional view of one embodiment of the film configuration of the multilayer film of the infrared light cut film 21.
In the film configuration shown in FIG. 3, an infrared light cut film 21 is configured by a multilayer film in which a first film 1 and a second film 2 having different refractive indexes are alternately stacked four times in total for a total of eight layers. Yes.
The thickness of each first film 1 is the same, and the thickness of each second film 2 is the same.

Preferably, when the center wavelength of the infrared light to be cut is λ0 and the refractive index of the film is n, the thickness t = x · λ0 / 4n (x = 0.9 to 1.1) is satisfied. The film thickness of the first film 1 and the film thickness of the second film 2 are set.
By setting the film thickness so as to satisfy the above conditions, the reflectance of the multilayer film with respect to infrared light can be effectively increased.

  For example, in the lamination of SiO film (silicon oxide film) / SiN film (silicon nitride film), the SiO film has a thickness of 131 nm and the SiN film has a thickness of 95 nm.

  In addition, when the same material as the material of the layer (insulating layer or the like) that is in contact with the infrared light cut film 21 at the lower layer or the upper layer is used for the first film 1, As shown in the cross-sectional view of FIG. 4, the first film 1 is disposed in the uppermost layer and the lowermost layer, and the uppermost layer and the lowermost layer are thicker than the first film 1 in a regular portion. It may be formed.

  The number of films to be stacked is not limited to two, and may be three or more. Further, the number of films to be stacked is not particularly limited as long as the total number is three or more. In the case of a total of two layers, it is difficult to obtain sufficient reflectance for infrared light, and it is difficult to sufficiently cut infrared light.

The solid-state imaging device of the present embodiment can be manufactured as follows, for example.
First, each layer up to the on-chip lens 18 is formed.
Next, for example, by using a low-temperature sputtering apparatus, the respective films constituting the multilayer film are successively and sequentially formed on the on-chip lens 18, thereby forming the infrared light cut film 21 composed of the multilayer film. To do. At this time, the film formation temperature of each film of the multilayer film needs to be 250 ° C. or less, more preferably 150 ° C. or less so as not to affect each layer below the already formed on-chip lens 18. .

By forming the infrared light cut film 21 using a low temperature film formation technique such as low temperature sputtering, it is possible to form a film at a low temperature. Thereby, since other layers are not affected at the time of film formation, the infrared light cut film 21 can be disposed without being caught by the place of the infrared light cut film 21.
Each of the films constituting the multilayer film of the infrared light cut film 21 is preferably made of a plurality of materials having a refractive index difference as large as possible. It is also suitable for forming a large material continuously.

According to the configuration of the solid-state imaging device of the present embodiment described above, the infrared light cut film 21 that transmits visible light but does not transmit infrared light is formed in the pixel on which the color filter 16 is formed. Thus, only visible light can be received and detected in this pixel. Thereby, a visible light image can be obtained using an image signal obtained from the pixel on which the color filter 16 is formed.
In addition, since the infrared light cut film 21 is not formed in the pixel in which the color filter 16 is not formed, visible light and infrared light can be received and detected in this pixel.
Therefore, an image signal (visible light + infrared light) obtained from a pixel on which the color filter 16 is not formed and an image signal (visible light only) obtained from the pixel on which the color filter is formed are calculated. Thus, an infrared light image can be obtained. The arithmetic processing in this case is simple arithmetic processing as compared with the configuration described in Patent Document 7 described above.

Further, since an image of visible light can be obtained by using an image signal obtained from the pixel on which the color filter 16 is formed, only normal visible light is received and detected without performing complicated calculations. A visible light image can be obtained by the same arithmetic processing as that of the solid-state imaging device.
Accordingly, an image of visible light can be obtained by the same arithmetic processing as that of a solid-state imaging device that receives and detects only normal visible light without performing complicated calculation.

  In addition, depending on the presence or absence of the color filter 16 and the infrared light cut film 21, pixels that receive infrared light and pixels that do not receive infrared light (do not receive infrared light) can be distributed. Even without providing an optical system, both visible light and infrared light can be received and detected.

In the present embodiment, since the infrared light cut film 21 is formed on the on-chip lens 18, the total thickness from the sensor unit 12 to the on-chip lens 18 is the same as that of the infrared light cut film 21. It is almost the same as the structure not formed.
Therefore, problems due to an increase in the total thickness from the sensor unit 12 to the on-chip lens 18 (for example, a decrease in sensitivity, an increase in color mixing, a deterioration in shading, etc.) can be avoided.

Here, as a comparative configuration, a configuration in which an infrared light cut film 21 is formed between the sensor unit 12 and the on-chip lens 18 is shown in a sectional view of FIG.
In the configuration shown in FIG. 8, an infrared light cut film 21 is formed in the upper layer of the wiring layer 13 inside the insulating layer 14 in which the wiring layer 13 is formed. That is, the infrared light cut film 21 is formed between the planarizing film 15 below the color filter 16 and the wiring layer 13, and is formed below the on-chip lens 18.
As a result, the total thickness from the sensor unit 12 to the on-chip lens 18 is increased as compared with a solid-state imaging device having a configuration in which no infrared light cut film is formed.
When the total thickness increases in this way, the range of light reaching the sensor unit 12 is narrowed, and the proportion of light absorbed on the way increases, so the amount of light reaching the sensor unit 12 decreases and sensitivity decreases. To do. In addition, light traveling obliquely from the on-chip lens 18 enters adjacent pixels and tends to cause color mixing. In addition, shading of the peripheral pixels and the central pixels of the pixel region is also deteriorated.

Further, since the color filter 16 needs to be formed on a flat surface, when the structure shown in FIG. 8 is manufactured, the infrared light cut film 21 is not formed after the infrared light cut film 21 is patterned. The remaining portion is filled with an insulating layer such as an oxide, and then the surface is flattened by a CMP (Chemical Mechanical Polishing) method or the like.
On the other hand, in the case of manufacturing the configuration of the present embodiment, since the infrared light cut film 21 is formed on the on-chip lens 18 and then the infrared light cut film 21 is formed thereon. It is only necessary to cover the surface with an insulating layer with good surface flatness after the patterning, and the step of flattening by the CMP method or the like becomes unnecessary, so that the number of steps can be expected to be reduced.

Next, FIG. 5 shows a schematic configuration diagram (cross-sectional view) of a solid-state imaging device according to another embodiment of the present invention.
In the present embodiment, as shown in FIG. 5, a planarization film 22 is provided between the on-chip lens 18 and the infrared light cut film 21.
Since other configurations are the same as those of the previous embodiment shown in FIG. 1, the same reference numerals are given and redundant description is omitted.

According to the above-described embodiment, a visible light image can be obtained using an image signal obtained from a pixel on which the color filter 16 is formed, as in the previous embodiment, and a complicated Even if the calculation is not performed, an image of visible light can be obtained by a calculation process similar to that of a solid-state imaging device that receives and detects only normal visible light.
Accordingly, an image of visible light can be obtained by the same arithmetic processing as that of a solid-state imaging device that receives and detects only normal visible light without performing complicated calculation.
Also, an image signal (visible light + infrared light) obtained from a pixel on which the color filter 16 is not formed and an image signal (visible light only) obtained from the pixel on which the color filter is formed are calculated. Thus, an infrared light image can be obtained.
Then, depending on the presence or absence of the color filter 16 and the infrared light cut film 21, pixels that receive infrared light and pixels that do not receive infrared light (does not receive infrared light) can be distributed. Even without providing an optical system, both visible light and infrared light can be received and detected.

  Furthermore, since the infrared light cut film 21 is formed on the on-chip lens 18, the total thickness from the sensor unit 12 to the on-chip lens 18 does not form the infrared light cut film 21. Therefore, problems due to an increase in the total thickness from the sensor unit 12 to the on-chip lens 18 (for example, a decrease in sensitivity, an increase in color mixing, a deterioration in shading, etc.) can be avoided.

  Furthermore, in the present embodiment, the planarization film 22 is provided therebetween, so that the infrared light cut film 21 has poor adhesion to the on-chip lens 18 or the material of the on-chip lens 18. Even when the selectivity of the etching rate of the material of the infrared light cut film 21 cannot be taken, the infrared light cut film 21 can be formed without causing a problem.

  Furthermore, depending on conditions such as the material and film thickness, there may be a problem that the lower surface of the infrared light cut film 21 has a curved shape along the curved surface of the on-chip lens 18. It can be avoided.

In the embodiment shown in FIG. 5, the planarization film 22 is provided between the on-chip lens 18 and the infrared light cut film 21, but on-chip instead of the planarization film 22. Another film may be provided between the lens 18 and the infrared light cut film 21.
Examples of the other films include a film for improving the adhesion of the infrared light cut film 21 and a film that serves as an etching stopper when the infrared light cut film 21 is patterned.

  By the way, when the infrared light cut film is provided on the on-chip lens and color mixing with adjacent pixels becomes a problem, for example, the pattern of the infrared light cut film may be made larger than the pixel size. The case is shown below.

FIG. 6 shows a schematic configuration diagram (cross-sectional view) of a solid-state imaging device according to still another embodiment of the present invention.
In the present embodiment, as shown in FIG. 6, the pattern of the infrared light cut film 21 formed on the on-chip lens 18 is made larger than the pixel size. The color filter 16 has a pattern that is approximately the same size as the pixel size.
For example, the width W2 of the infrared light cut film 21 is set to be about 0.05 μm to 5.0 μm larger than the width W1 of the pixel.

Thus, by making the pattern of the infrared light cut film 21 larger than the pixel size, from an adjacent pixel where the infrared light cut film 21 is not formed to a pixel formed by the infrared light cut film 21. Changes in the image signal due to the incidence of infrared light, that is, color mixing can be prevented.
By making the pattern of the infrared light cut film 21 larger than the pixel size, infrared light obliquely incident from adjacent pixels, which causes color mixing, is also cut at a portion where the infrared light cut film 21 is enlarged. be able to.

  Other configurations are the same as those of the previous embodiment shown in FIG.

According to the present embodiment described above, a visible light image is obtained using the image signal obtained from the pixel on which the color filter 16 is formed, as in the previous embodiment shown in FIG. Thus, an image of visible light can be obtained by the same arithmetic processing as that of a solid-state imaging device that receives and detects only normal visible light without performing complicated calculation.
Accordingly, an image of visible light can be obtained by the same arithmetic processing as that of a solid-state imaging device that receives and detects only normal visible light without performing complicated calculation.
Also, an image signal (visible light + infrared light) obtained from a pixel on which the color filter 16 is not formed and an image signal (visible light only) obtained from the pixel on which the color filter is formed are calculated. Thus, an infrared light image can be obtained.
Then, depending on the presence or absence of the color filter 16 and the infrared light cut film 21, pixels that receive infrared light and pixels that do not receive infrared light (does not receive infrared light) can be distributed. Even without providing an optical system, both visible light and infrared light can be received and detected.

  Furthermore, since the infrared light cut film 21 is formed on the on-chip lens 18, the total thickness from the sensor unit 12 to the on-chip lens 18 does not form the infrared light cut film 21. Therefore, problems due to an increase in the total thickness from the sensor unit 12 to the on-chip lens 18 (for example, a decrease in sensitivity, an increase in color mixing, a deterioration in shading, etc.) can be avoided.

  Further, according to the present embodiment, the width W2 of the infrared light cut film 21 is made larger than the width W1 of the pixel, and the pattern of the infrared light cut film 21 is made larger than the pixel size. Color mixing due to the incidence of infrared light from adjacent pixels can be prevented.

Next, FIG. 7 shows a schematic configuration diagram (cross-sectional view) of a solid-state imaging device according to another embodiment of the present invention.
In the present embodiment, in particular, as shown in FIG. 7, the curved surface shape of the on-chip lens 18 is transferred to the infrared light cut film 21, and the upper surface 21 </ b> A of the infrared light cut film 21 is transferred to the on-chip lens 18. It has a curved surface shape similar to the curved surface of the upper surface 18A.

According to the present embodiment, as in the embodiment shown in FIG. 1, a visible light image can be obtained without performing a complicated calculation, and visible light can be obtained without providing a large optical system. And infrared light can be received and detected. Furthermore, problems due to an increase in the total thickness from the sensor unit 12 to the on-chip lens 18 (for example, a decrease in sensitivity, an increase in color mixing, a deterioration in shading, etc.) can be avoided.
Further, according to the present embodiment, the upper surface 21A of the infrared light cut film 21 has a curved surface shape similar to the curved surface of the upper surface 17A of the on-chip lens 18, so that not only the on-chip lens 18 but also red Incident light can also be collected by the external light cut film 21.
Thereby, since light can be incident on the sensor unit 12 from a wider range, the sensitivity of the pixel provided with the infrared light cut film 21 can be increased.

  In each of the above-described embodiments, the case where three color filters of the primary colors of red R, green G, and blue B are used as the color filter 16 has been described. However, complementary color filters (cyan Cy, magenta Mg) , Yellow Ye) and other color filters may be used.

Further, in each of the above-described embodiments, the color filter 16 is not formed in a pixel that does not have the infrared light cut film 21 and receives and detects visible light and infrared light. However, in the present invention, visible light is not formed. It is also possible to form a color filter in a pixel that receives infrared light.
For example, among the color filters formed on pixels that receive only visible light, the same color filter as the color filter of any color can be formed on the pixels that receive visible light and infrared light. is there. With this configuration, an image signal from a pixel that receives only visible light on which the same color filter is formed is subtracted from an image signal from a pixel that receives visible light and infrared light, thereby obtaining an infrared signal. An optical image signal is obtained.
Accordingly, there is an advantage that the arithmetic processing for obtaining the image signal of the infrared light can be simplified.

In each of the above embodiments, the case where a silicon substrate is used has been described. However, the present invention can also be applied to the case where a semiconductor substrate other than a silicon substrate is used.
Moreover, it is good also as a structure which formed the silicon epitaxial layer in the surface side of the silicon substrate, and formed the sensor part in this silicon epitaxial layer.

In each of the above-described embodiments, the case where the present invention is applied to a CMOS solid-state image sensor has been described. However, the present invention can be similarly applied to solid-state image sensors having other configurations, for example, CCD solid-state image sensors. .
In the CCD solid-state imaging device, since a light shielding film is formed to cover the transfer electrode of the charge transfer unit, a relatively large step is formed between the sensor unit and the charge transfer unit. By applying the configuration of the present invention in which the film is formed above the on-chip lens, the infrared light cut film can be formed more easily than the configuration formed below the on-chip lens.

  The present invention is not limited to the above-described embodiment, and various other configurations can be taken without departing from the gist of the present invention.

1 is a schematic configuration diagram (cross-sectional view) of a solid-state imaging device according to an embodiment of the present invention. A is a plan view showing the arrangement of the color filter of FIG. B is a plan view showing the arrangement of the infrared light cut film of FIG. It is sectional drawing which shows one form of the multilayer film of the infrared-light cut film | membrane of FIG. It is sectional drawing which shows the other form of the multilayer film of the infrared-light cut film | membrane of FIG. It is a schematic block diagram (sectional drawing) of the solid-state image sensor of other embodiment of this invention. It is a schematic block diagram (sectional drawing) of the solid-state image sensor of further another embodiment of this invention. It is a schematic block diagram (sectional drawing) of the solid-state image sensor of another embodiment of this invention. It is a schematic block diagram (sectional drawing) of the solid-state image sensor of the structure which provided the infrared-light cut film in the lower layer of the color filter.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 1st film | membrane, 2nd film | membrane, 11 Silicon substrate, 12 Sensor part, 14, 17 Insulating layer, 15 Planarization film | membrane, 16 Color filter, 18 On-chip lens, 21 Infrared light cut film | membrane, 22 Planarization film

Claims (6)

A color filter and an on-chip lens that collects incident light are respectively formed above the sensor unit that performs photoelectric conversion, corresponding to the sensor unit of each pixel,
In some pixels of the pixel area, the color filter is formed, and an infrared light cut film that transmits visible light but does not transmit infrared light is formed above the on-chip lens. A solid-state image pickup device characterized by that.   2. The solid-state imaging device according to claim 1, wherein the color filter and the infrared light cut film are not formed in pixels other than the some of the pixels in the pixel region.   The solid-state imaging device according to claim 1, wherein the infrared light cut film is a multilayer film in which films having different refractive indexes are stacked.   The solid-state imaging device according to claim 1, wherein another film is formed between the on-chip lens and the infrared light cut film.   The solid-state imaging device according to claim 1, wherein a pattern of the infrared light cut film is formed larger than the pixel. The solid-state imaging device according to claim 1, wherein an upper surface of the infrared light cut film is a curved surface similar to the upper surface of the on-chip lens.

Images