JP2008076084A - On-vehicle color sensor, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle color sensor which easily copies with not only sensing of light in a visible domain but also sensing of light in a near infrared region, and also to provide its manufacturing method. <P>SOLUTION: Light receiving elements 20, 21, 22, 23 for outputting electric signals corresponding to the quantity of each light in an ultraviolet region, in a visible region, and in the near infrared region, are arrayed on the upper surface of a substrate 10, and a near infrared light cut filter 40 is arranged on the light receiving element 20 through a red filter 30, and near infrared light cut filters 41, 42 are arranged on the light receiving elements 21, 22 through green filters 31, 32, and a visible light cut filter 43 is arranged on the light receiving element 23. An ultraviolet cut glass plate 50 is arranged on the near infrared light cut filters 40, 41, 42 and the visible light cut filter 43. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an in-vehicle color sensor, for example, an in-vehicle color sensor that can be applied to other applications using near-infrared light while maintaining detection performance of vehicle lights (tail lamps, head lamps).

  There is a light distribution control technique such as imaging the front of a vehicle using an in-vehicle imaging device during night driving, detecting a tail lamp of a preceding vehicle or a head lamp of an oncoming vehicle, and switching a high beam / low beam state of the head lamp of the own vehicle. In order to perform such control, it is necessary to discriminate ambient light such as vehicle lights (tail lamps, head lamps) and orange reflectors with high sensitivity.

As a conventional example of a discrimination method focusing on the color of a light source, there is a technique for detecting a color arrangement ratio of two or three colors (for example, Patent Document 1).
U.S. Pat. No. 6,774,988

  However, the near-infrared spectral sensitivity range of the color image sensor has been cut to improve the discrimination sensitivity. For applications that require near-infrared spectral sensitivity, such as raindrop sensors or night surveillance cameras. Could not be applied. This is a detrimental effect in consolidating the functions of the sensor group mounted in the vicinity of the room mirror and saving the mounting space.

  In addition, there is a problem in obtaining the spectral sensitivity in the visible region and near infrared region of two or more colors with the same image sensor. General-purpose color filters have spectral sensitivity in the near-infrared region. Generally, either a separate infrared-cut glass or a design that limits the spectral sensitivity characteristics of the image sensor itself to the visible region is used. It is. In any case, there is room for improvement in providing the presence / absence of near-infrared sensitivity in units of pixels of the color image sensor.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an in-vehicle color sensor that can easily accommodate not only visible light sensing but also near-infrared light sensing, and a method for manufacturing the same. It is to provide.

  In order to solve the above-described problems, in the invention described in claim 1, a plurality of substrates are arranged on the upper surface of the substrate, and electrical signals corresponding to the amounts of light in the ultraviolet region, visible region, and near infrared region are output. And a first near-infrared light cut filter disposed on a first light-receiving element of the adjacent light-receiving elements through a red filter that selectively allows red light to pass through, A second near-infrared light cut filter disposed on a second light-receiving element among the adjacent light-receiving elements via a green filter that selectively transmits green light; and A visible light cut filter disposed on the third light receiving element, and an ultraviolet light disposed on the first near infrared light cut filter, the second near infrared light cut filter, and the visible light cut filter. The gist of having a cut glass plate To.

  According to the first aspect of the present invention, when light in the visible region enters, red light is detected by the first light receiving element and green light is detected by the second light receiving element. Further, when near-infrared light enters, the third light receiving element detects near-infrared light. Therefore, it is possible to provide an in-vehicle color sensor that can easily cope with not only visible light sensing but also near infrared light sensing.

  The in-vehicle color sensor according to claim 1, wherein the first near-infrared light cut filter and the second near-infrared light cut filter are formed on a lower surface of the ultraviolet cut glass plate. It is good also as what is formed.

  As described in claim 3, in the on-vehicle color sensor according to claim 2, when a visible light curable adhesive is interposed between the substrate and the ultraviolet cut glass plate, the bonding is easily performed. It can be carried out.

  According to a fourth aspect of the present invention, in the on-vehicle color sensor according to the first aspect, a blue filter that selectively allows blue light to pass over the fourth light receiving element of the adjacent light receiving elements. If a third near-infrared light cut filter arranged further is further provided, blue can be detected.

  As described in claim 5, in the on-vehicle color sensor according to claim 1, a color filter and a cut filter are interposed in the light receiving elements arranged on the substrate other than the first to third light receiving elements. If light is received through the ultraviolet cut glass plate, light in the visible region and near infrared region can be detected.

  6. The in-vehicle color sensor according to claim 1, wherein the first near-infrared light cut filter, the second near-infrared light cut filter, and the visible light cut filter according to claim 1. If it consists of a thin film, it can arrange | position easily.

  The first impurity diffusion region of the second conductivity type is formed in the surface layer portion of the silicon substrate of the first conductivity type serving as the first conductivity type impurity diffusion region, and the first impurity A second impurity diffusion region of the first conductivity type shallower than the first impurity diffusion region is formed in the surface layer portion of the silicon substrate in the diffusion region, and further, in the surface layer portion of the silicon substrate in the second impurity diffusion region. A third impurity diffusion region of the second conductivity type shallower than the second impurity diffusion region is formed, and near infrared light is photoelectrically converted at the interface between the bottom surface of the first impurity diffusion region and the silicon substrate. A deepest first PN junction is formed, and second for photoelectric conversion of red light at the interface between the bottom surface of the second impurity diffusion region and the first impurity diffusion region. Deep second PN junction And the third deepest third PN junction for photoelectrically converting green light is formed at the interface between the bottom surface of the third impurity diffusion region and the second impurity diffusion region. The gist.

  According to the seventh aspect of the present invention, when light in the visible region enters, red light is detected at the second PN junction, and green light is detected at the third PN junction. Further, when near-infrared light enters, near-infrared light is detected at the first PN junction. Therefore, it is possible to provide an in-vehicle color sensor that can easily cope with not only visible light sensing but also near infrared light sensing.

  According to an eighth aspect of the present invention, in the on-vehicle color sensor according to the seventh aspect of the present invention, a first conductivity type shallower than the third impurity diffusion region is formed in a surface layer portion of the silicon substrate in the third impurity diffusion region. A fourth impurity diffusion region is further formed, and the shallowest fourth PN junction for photoelectrically converting blue light at the interface between the bottom surface of the fourth impurity diffusion region and the third impurity diffusion region When formed, blue light can be detected.

  A method for manufacturing an in-vehicle color sensor according to claim 6, wherein a number of light receiving elements are arranged on the upper surface of the substrate, and a red filter is formed on the first light receiving element. In addition, a first step of forming a green filter on the second light receiving element, a second step of forming an SOG film on the entire surface including the red filter and the green filter, and the SOG film The on-vehicle color according to claim 6, further comprising a third step of patterning a thin film for a near-infrared light cut filter on the top and patterning a thin film for a visible light cut filter on the SOG film. The sensor can be manufactured, and the SOG film can protect the red filter and the green filter from the chemical solution in the manufacturing process.

  According to a tenth aspect of the present invention, in the method for manufacturing an in-vehicle color sensor according to the ninth aspect, an electrode pad is formed on the upper surface of the substrate in the first step, and the third step is followed by the step of forming the electrode pad on the electrode pad. If the fourth step of exposing the electrode pad by removing the SOG film is included, an in-vehicle color sensor including the electrode pad can be easily manufactured.

  As described in claim 11, in the on-vehicle color sensor manufacturing method according to claim 9 or 10, the thin film for the near infrared light cut filter in the third step is formed by vapor deposition, or As described above, in the method for manufacturing an on-vehicle color sensor according to any one of claims 9, 10, and 11, the visible light cut filter thin film in the third step may be formed by vapor deposition.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
The present embodiment is applied to a vehicle light control device, and FIG.

  In FIG. 1, an in-vehicle color sensor (imaging device) 3 is provided on the back surface of the room mirror 2 of the vehicle 1. The in-vehicle color sensor 3 can capture an image of the front of the vehicle 1 in the traveling direction. The in-vehicle color sensor 3 is connected to the microprocessor 4, and image data captured by the in-vehicle color sensor 3 is sent to the microprocessor 4. The microprocessor 4 can perform various processes from the imaging data and detect the tail lamp of the preceding vehicle and the headlamp of the oncoming vehicle from the imaging data.

  An electronic control unit (ECU) 5 for light control is connected to the microprocessor 4. The headlamp 6 can be controlled by the electronic control unit 5. That is, the electronic control unit 5 controls the headlamp 6 to a high beam / low beam based on the presence or absence of a front vehicle (a tail lamp of a preceding vehicle, a head lamp of an oncoming vehicle) by the microprocessor 4.

  FIG. 2 is a configuration diagram of an optical system of the in-vehicle color sensor 3. In FIG. 2, an image sensor 8 with a cover glass is disposed at the focal position of the lens 7, and light from the front of the vehicle is condensed on the image sensor 8 with a cover glass through the lens 7.

FIG. 3 is a perspective view of the image sensor 8 with a cover glass of the in-vehicle color sensor 3. In FIG. 3, the image sensor 8 with a cover glass of the in-vehicle color sensor 3 has a large number of pixels 9.
4A is a plan view of an image sensor with a cover glass of a vehicle-mounted color sensor, FIG. 4B is a longitudinal sectional view taken along line AA in FIG. 4A, and FIG. It is a longitudinal cross-sectional view in the BB line. In FIG. 4, the ultraviolet cut glass plate 50 as the cover glass and the cut filters 40, 41, 42, 43 are removed, and the state of only the image sensor is shown in FIG. 5, (a) is the plane of the image sensor of the in-vehicle color sensor. It is a figure, (b) is a longitudinal cross-sectional view in the AA line of (a), (c) is a longitudinal cross-sectional view in the BB line of (a).

  FIG. 6 shows a state in which the filters 30, 31, and 32 are removed in FIG. 5, (a) is a plan view of the image sensor of the in-vehicle color sensor, and (b) is a line AA in (a). It is a longitudinal cross-sectional view, (c) is a longitudinal cross-sectional view in the BB line of (a).

  In FIG. 6, on the upper surface of the substrate 10, as indicated by reference numerals 20, 21, 22, and 23, a number of light receiving elements that output electrical signals corresponding to the amounts of light in the ultraviolet region, visible region, and near infrared region are arranged vertically and horizontally. ing. The light receiving elements (20 to 23) form pixels, and silicon photodiodes are used as the light receiving elements (20 to 23).

  Here, regarding the adjacent light receiving elements, a total of four light receiving elements of two adjacent vertical and two horizontal sides will be described as one unit (see FIG. 4). That is, the four adjacent light receiving elements have the same configuration in each unit with the four light receiving elements as one unit.

  In FIG. 5, a red filter 30 that selectively transmits red light is disposed on the light receiving element 20. A green filter 31 that selectively transmits green light is formed on the light receiving element 21. A green filter 32 that selectively transmits green light is formed on the light receiving element 22.

  In FIG. 4, an ultraviolet cut glass plate 50 is disposed above the substrate 10 so as to face the substrate 10. Near-infrared light cut filters 40, 41, 42 and a visible light cut filter 43 are formed on the lower surface of the ultraviolet cut glass plate 50. The near infrared light cut filter 40 is disposed on the red filter 30. The near-infrared light cut filter 41 is disposed on the green filter 31. The near infrared light cut filter 42 is disposed on the green filter 32. The visible light cut filter 43 is disposed on the light receiving element 23.

  In this way, the near-infrared light cut filter 40 is disposed on the light receiving element 20 via the red filter 30 that selectively allows red light to pass through. Further, near-infrared light cut filters 41 and 42 are disposed on the light receiving elements 21 and 22 via green filters 31 and 32 that selectively pass green light. Further, a visible light cut filter 43 is disposed on the light receiving element 23. Further, an ultraviolet cut glass plate 50 is disposed on the entire surface so as to face the substrate 10.

  Therefore, the light incident from the outside of the vehicle is cut in the ultraviolet region by the ultraviolet cut glass plate 50, further, the near infrared region light is cut by the near infrared light cut filter 40, and the red light is received through the red filter 30. 20 is subjected to photoelectric conversion. Further, the light incident from the outside of the vehicle is cut in the ultraviolet region by the ultraviolet cut glass plate 50, and further, the near-infrared region light is cut by the near-infrared light cut filters 41, 42, and green through the green filters 31, 32. Light is photoelectrically converted in the light receiving elements 21 and 22. Further, the light incident from outside the vehicle is cut in the ultraviolet region by the ultraviolet cut glass plate 50, the visible light is cut by the visible light cut filter 43, and the near infrared light is photoelectrically converted in the light receiving element 23.

  As described above, the basic four-pixel arrangement structure of the color imaging element with a cover glass has a visible red (R), green (G), green (G), and near-infrared infrared red (IR). ). Moreover, it can prevent that a color filter material deteriorates with an ultraviolet-ray by using the ultraviolet-ray cut glass plate 50 as a cover glass (it can improve UV resistance).

  In this way, in an image sensor using a general-purpose color filter, it is necessary to cut the near infrared region associated with red (R) and green (G) pixels, and visible to near infrared (IR) pixels. It is necessary to cut the area. Therefore, a near-infrared light cut filter and a visible light cut filter are formed on the ultraviolet cut glass plate 50 to realize an image sensor with a cover glass having desired color characteristics.

Next, the operation of the vehicle light control device will be described.
Now, at night, as shown in FIG. 7, the vehicle travels on the road where the orange reflector 64 is installed, the preceding vehicle 65 and the oncoming vehicle 67 are present, and the tail lamp 66 and the head lamp 68 are lit. As shown in FIG. 8, by picking up an image by the in-vehicle color sensor 3 and processing by the microprocessor 4, it is possible to extract the red light and detect the tail lamp 66 of the preceding vehicle. Can be recognized.

  In other words, the headlamp 68 of the oncoming vehicle is relatively bright and easy to recognize, but the taillight 66 of the preceding vehicle is dark, so it is easy to misrecognize the orange reflector 64 and other disturbance light as the taillight of other vehicles. In the form, it is possible to distinguish the tail lamp of the preceding vehicle from other lights by utilizing the fact that the tail lamp is red (the red light of the tail lamp can be discriminated from white light or orange light which is disturbance light). it can).

  In particular, by taking the ratio of green light to red light, it is possible to more accurately determine whether the light is red light. For red light, the output of green light is small compared to the output of red light, and for other light, for example white light, the ratio of the output of green light to the output of red light is close to “1”. It is possible to discriminate between white light and orange light from the reflector and red light from the tail lamp of the preceding vehicle.

Based on this result, the headlamp 6 of the own vehicle is controlled. For example, if there is a vehicle (preceding vehicle or oncoming vehicle) ahead of the vehicle at night, the headlamp of the vehicle is set to a low beam.
In this way, the light distribution control of the headlamp 6 is performed by detecting the tail lamp 66 of the preceding vehicle 65 and the headlamp 68 of the oncoming vehicle 67. As a pixel arrangement structure of a color imaging element having the function, the conventional examples are visible (red), green (G), and blue (B), and did not have a near infrared region. In the present embodiment, the arrangement of the basic four pixels is red (R), green (G), green (G), and near-infrared (IR) in the visible range. In this way, by setting the spectral sensitivity of the color sensor to red (R), green (G), and near infrared region (IR), the raindrop sensor (rain sensor) is maintained while maintaining the detection performance of the tail lamps and headlamps of surrounding vehicles. ) And night surveillance cameras, etc., can also be applied to applications that require near-infrared spectral sensitivity. When used as a night surveillance camera, light including near infrared components is emitted from the headlamp of the vehicle, and the reflected light is received and displayed on a monitor (display). Alternatively, near infrared light is emitted in front of the vehicle from a projector different from the headlamp of the vehicle, and the reflected light is received and displayed on a monitor (display device). When used as a raindrop sensor (rain sensor), near-infrared light is emitted from a projector in the passenger compartment to the windshield, and reflected light from the raindrop attached to the windshield is received to detect the raindrop. At this time, raindrops can be accurately detected even at night by using near infrared light.

According to the above embodiment, the following effects can be obtained.
(1) As shown in FIG. 4, the substrate 10 and a plurality of light receiving elements (20, 21, 22, 23) and the first near-infrared light cut disposed on the first light-receiving element 20 among the adjacent light-receiving elements via a red filter 30 that selectively allows red light to pass therethrough. The second near-infrared light cut disposed on the filter 40 and the second light-receiving elements 21 and 22 among the adjacent light-receiving elements via the green filters 31 and 32 that selectively allow the green light to pass therethrough. Filters 41 and 42, a visible light cut filter 43 disposed on the third light receiving element 23 of the adjacent light receiving elements, a first near infrared light cut filter 40, and a second near infrared light. On the cut filters 41 and 42 and the visible light cut filter 43 An ultraviolet cut glass plate 50 arranged, having a. Thus, when light in the visible region enters, the first light receiving element 20 detects red light, and the second light receiving elements 21 and 22 detect green light. When near-infrared light enters, the third light receiving element 23 detects near-infrared light. Therefore, it is possible to provide an in-vehicle color sensor that can easily handle not only visible light sensing but also near infrared light sensing. In addition, it is possible to reduce the size and provide IR sensitivity for each pixel of the color image sensor.
(Second Embodiment)
Next, the second embodiment will be described focusing on the differences from the first embodiment.

  FIG. 9 shows an in-vehicle color sensor according to this embodiment instead of FIG. 4, (a) is a plan view of an image sensor with a cover glass of the in-vehicle color sensor, and (b) is an A- It is a longitudinal cross-sectional view in the A line, (c) is a longitudinal cross-sectional view in the BB line of (a).

  In FIG. 9, an ultraviolet cut glass plate 50 and a substrate 10 (substrate on which a light receiving element and a color filter are formed) are bonded together. A visible light curable adhesive 60 is interposed between the substrate 10 and the ultraviolet cut glass plate 50. That is, in the process of bonding the glass plate 50 and the substrate 10, it is necessary to quickly bond and cure after the relative positioning of both, but when using an ultraviolet cut glass plate for the glass plate, an ultraviolet curable adhesive Cannot be used, the visible light curable adhesive 60 is used. Thereby, it can bond easily.

Specific examples of the visible light curable adhesive 60 include a Lux Track Series (acrylic base material adhesive) manufactured by Toagosei Co., Ltd.
(Third embodiment)
Next, the third embodiment will be described focusing on the differences from the first embodiment.

  FIG. 10 shows an in-vehicle color sensor according to this embodiment instead of FIG. 4, (a) is a plan view of an image sensor with a cover glass of the in-vehicle color sensor, and (b) is an A- It is a longitudinal cross-sectional view in the A line, (c) is a longitudinal cross-sectional view in the BB line of (a).

  In the first embodiment shown in FIG. 4, the arrangement of the basic four pixels is red (R), green (G), green (G), and near infrared (IR) in the visible range. In the embodiment, the arrangement of four basic pixels is red (R), green (G), blue (B), and near-infrared (IR) in the visible range.

  That is, the blue filter 34 that selectively transmits blue light is formed on the light receiving element 24 among the adjacent light receiving elements on the upper surface of the substrate 10, and the near infrared light cut filter 44 is disposed thereon. ing.

In this manner, the third near-infrared light cut filter 44 disposed on the fourth light receiving element 24 among the adjacent light receiving elements via the blue filter 34 that selectively transmits blue light. Further, a configuration may be further provided, whereby blue can be detected.
(Fourth embodiment)
Next, the fourth embodiment will be described focusing on the differences from the first embodiment.

  FIG. 11 shows an in-vehicle color sensor according to this embodiment instead of FIG. 4, (a) is a plan view of an image sensor with a cover glass of the in-vehicle color sensor, and (b) is an A- It is a longitudinal cross-sectional view in the A line, (c) is a longitudinal cross-sectional view in the BB line of (a).

  The arrangement pattern of the visible light cut filter 43 in FIG. 4 is changed, and no visible light cut filter is provided on the light receiving element 25 in FIG. In other words, the light receiving elements 25 arranged on the substrate 10 other than the first to third light receiving elements are configured to receive light through the ultraviolet cut glass plate 50 without any color filters or cut filters.

Thus, the light receiving element 25 receives light through the ultraviolet cut glass plate 50 and outputs a signal corresponding to the amount of light in the visible region and near infrared region other than the ultraviolet region. That is, light in the visible range and near infrared range can be detected. The output of the light receiving element 25 can be used as a solar radiation sensor. That is, the present invention can be applied to an auto air conditioner system by using it as an optical sensor having spectral sensitivity in all wavelengths in the near infrared region and the visible region.
(Fifth embodiment)
Next, the fifth embodiment will be described with a focus on differences from the first embodiment.

FIG. 12 is a longitudinal sectional view of the image sensor with a cover glass of the in-vehicle color sensor in the present embodiment.
In FIG. 12, a near-infrared light cut filter 40 is disposed on the light receiving element 20 on the upper surface of the substrate 10 via a red filter 30. Further, near-infrared light cut filters 41 and 42 are disposed on the light receiving elements 21 and 22 via green filters 31 and 32. A visible light cut filter 43 is disposed on the light receiving element 23. An ultraviolet cut glass plate 50 is disposed on the near infrared light cut filters 40, 41, 42 and the visible light cut filter 43.

  Here, on the substrate 10, an SOG (Spin On Glass) film 72 is formed on the light receiving elements 20, 21, 22, and 23, and near-infrared light cut filters 40, 41, and 42 and visible light are formed thereon. A cut filter 43 is arranged. The near-infrared light cut filters 40, 41, and 42 and the visible light cut filter 43 are made of thin films. An electrode pad 73 is formed on the upper surface of the substrate 10.

In FIG. 12, the light receiving elements 20, 21, 22, and 23 are arranged in a horizontal row on the substrate 10, but this is for explanation and the arrangement is the same as FIG. 4.
Next, a method for manufacturing an in-vehicle color sensor in the present embodiment will be described.

  As shown in FIG. 13A, the light receiving elements 20, 21, 22, 23 and the electrode pads 73 are formed on the substrate 10, and the red filter 30 and the light receiving elements 21, 22 are formed on the light receiving element 20. Green filters 31 and 32 are formed on the substrate, respectively.

  Then, as shown in FIG. 13B, an SOG film 72 is formed on the entire surface of the substrate 10. Further, as shown in FIG. 13C, a resist 74 is applied on the SOG film 72 on the substrate 10 (formed on the entire surface). Subsequently, as shown in FIG. 13D, the resist 74 is patterned to remove the near infrared light cut region.

  Then, as shown in FIG. 13E, a near infrared light cut filter thin film 75 is formed on the entire surface of the substrate 10 (on the resist 74) by vapor deposition. Further, as shown in FIG. 14A, the resist 74 is removed by lift-off to leave a near infrared light cut filter thin film 75 in a predetermined region. That is, the near-infrared light cut filter thin film 75 is disposed on the light receiving elements 20, 21, and 22.

  Subsequently, as shown in FIG. 14B, a resist 76 is applied on the substrate 10 (on the near infrared light cut filter thin film 75) (formed on the entire surface). Then, as shown in FIG. 14C, the resist 76 is patterned to remove the visible light cut region. Further, as shown in FIG. 14D, a visible light cut filter thin film 77 is formed on the entire surface of the substrate 10 (on the resist 76) by vapor deposition. Further, as shown in FIG. 15A, the visible light cut filter thin film 77 in the unnecessary region is removed by lift-off, and the visible light cut filter thin film 77 is left in the predetermined region. That is, the visible light cut filter thin film 77 is disposed on the light receiving element 23.

  Subsequently, as shown in FIG. 15B, a resist 78 is applied on the substrate 10 (on the visible light cut filter thin film 77) (formed on the entire surface). Then, as shown in FIG. 16, after the resist 78 is patterned to remove the electrode pad placement region, dry etching is performed using the resist 78 as a mask to expose the electrode pad 73. Then, when the ultraviolet cut glass plate 50 is disposed after the resist 78 is peeled and removed, the in-vehicle color sensor shown in FIG. 12 is obtained.

  In such a manufacturing process, since the SOG film 72 is interposed when the thin film 75 for the near-infrared light cut filter and the thin film 77 for the visible light cut filter are formed by the photo process, the color filters 30, 31 and 32 are not damaged by chemicals.

Note that the thin-film configuration of the near-infrared light cut filter has an aluminum oxide film (Al ₂ O ₃ ) as the first layer, and a titanium oxide film (TiO ₂ ) and a silicon oxide film (SiO ₂ ) alternately with a predetermined film thickness. You may laminate. The visible light cut filter may have a thin film configuration in which silicon films (Si) and silicon oxide films (SiO ₂ ) are alternately stacked.

According to the above embodiment, the following effects can be obtained.
(2) As shown in FIG. 12, since the near-infrared light cut filters 40, 41, and 42 and the visible light cut filter 43 are made of thin films, an in-vehicle color sensor can be easily manufactured by a semiconductor process (easily Can be placed).

  (3) In particular, as a method for manufacturing an in-vehicle color sensor, a number of light receiving elements (20, 21, 22, 23) are arranged on the upper surface of the substrate 10 as shown in FIG. The red filter 30 is formed on the light receiving element 20 and the green filters 31 and 32 are formed on the second light receiving elements 21 and 22 (first step). As shown in FIG. SOG film 72 is formed on the entire surface of substrate 10 including 30 and green filters 31 and 32 (second step), and near-infrared light is cut on SOG film 72 as shown in FIG. The filter thin film 75 was patterned, and the visible light cut filter thin film 77 was patterned on the SOG film 72 (third step). Therefore, the on-vehicle color sensor having the structure (2) can be manufactured. Further, the SOG film 72 can protect the red filter 30 and the green filters 31 and 32 from the chemical solution in the manufacturing process.

(4) Here, as shown in FIG. 13A, the electrode pad 73 is formed on the upper surface of the substrate 10 in the first step, and on the electrode pad 73 after the third step, as shown in FIG. Since the fourth step of exposing the electrode pad 73 by removing the SOG film 72 is included, an in-vehicle color sensor including the electrode pad 73 can be easily manufactured.
(Sixth embodiment)
Next, the sixth embodiment will be described with a focus on differences from the first embodiment.

FIG. 17 is a longitudinal sectional view of the image sensor of the in-vehicle color sensor in the present embodiment.
In the present embodiment of FIG. 17, the spectral sensitivity is given by the structure of the color sensor without using the color filter, the cut filter, and the cut glass plate.

  A deep N-type impurity diffusion region 91 is formed in the surface layer portion of the P-type silicon substrate 90. The P-type silicon substrate 90 is a first conductivity-type silicon substrate that becomes an impurity diffusion region of the first conductivity type. In this example, the P-type is the first conductivity type and the N-type is the second conductivity type.

  A P-type impurity diffusion region 92 shallower than the N-type impurity diffusion region 91 is formed in the surface layer portion of the P-type silicon substrate 90 in the N-type impurity diffusion region 91. An N-type impurity diffusion region 93 shallower than the P-type impurity diffusion region 92 is formed in the surface layer portion of the P-type silicon substrate 90 in the P-type impurity diffusion region 92. A P-type impurity diffusion region 94 shallower than the N-type impurity diffusion region 93 is formed in the surface layer portion inside the N-type impurity diffusion region 93 in the P-type silicon substrate 90.

  Therefore, there is a PN junction between the bottom of the P-type impurity diffusion region 92 and the N-type impurity diffusion region 91 at a position shallower than the PN junction between the bottom of the N-type impurity diffusion region 91 and the P-type silicon substrate 90. There is a PN junction between the bottom surface of the N-type impurity diffusion region 93 and the P-type impurity diffusion region 92 at a position shallower than the PN junction. There is a PN junction between the bottom surface of the P-type impurity diffusion region 94 and the N-type impurity diffusion region 93 at a position shallower than the PN junction.

  A current measuring device 95 is arranged between the P-type silicon substrate 90 and the N-type impurity diffusion region 91. A current measuring device 96 is disposed between the N-type impurity diffusion region 91 and the P-type impurity diffusion region 92. A current measuring device 97 is disposed between the P-type impurity diffusion region 92 and the N-type impurity diffusion region 93. A current measuring device 98 is disposed between the N-type impurity diffusion region 93 and the P-type impurity diffusion region 94.

  Then, the P-type silicon substrate 90 is irradiated (received) with light from above the P-type silicon substrate 90. Then, a current due to IR photons flows at the PN junction between the bottom surface of the N-type impurity diffusion region 91 and the P-type silicon substrate 90, and this is detected by the first current measuring device 95. A current due to red photons flows at the PN junction between the bottom surface of the P-type impurity diffusion region 92 and the N-type impurity diffusion region 91, and this is detected by the second current measuring device 96. A current due to green photons flows at the PN junction between the bottom surface of the N-type impurity diffusion region 93 and the P-type impurity diffusion region 92, and this is detected by the third current measuring device 97. A current due to blue photons flows at the PN junction between the bottom surface of the P-type impurity diffusion region 94 and the N-type impurity diffusion region 93, and this is detected by the fourth current measuring device 98. Thereby, necessary spectral sensitivity can be given.

As shown in FIG. 18 instead of FIG. 17, the P-type impurity diffusion region 94 in FIG. 17 may be eliminated to detect near infrared light, red light, and green light.
According to the above embodiment, the following effects can be obtained.

  (5) A P-type first impurity diffusion region 91 is formed in the surface layer portion of the P-type silicon substrate 90, and the P-type first impurity diffusion region 91 is shallower than the impurity diffusion region 91 in the surface layer portion of the silicon substrate 90 in the impurity diffusion region 91. A second impurity diffusion region 92 is formed, and an N-type third impurity diffusion region 93 shallower than the impurity diffusion region 92 is formed in the surface layer portion of the silicon substrate 90 in the impurity diffusion region 92. The deepest first PN junction for photoelectric conversion of near-infrared light is formed at the interface between the bottom surface of silicon and the silicon substrate 90, and at the interface between the bottom surface of the impurity diffusion region 92 and the impurity diffusion region 91. The second deepest second PN junction for photoelectrically converting red light is formed, and the green light is photoelectrically converted at the interface between the bottom surface of the impurity diffusion region 93 and the impurity diffusion region 92. Third PN junction deep third order is formed. Thereby, when light in the visible region enters, red light is detected at the second PN junction, and green light is detected at the third PN junction. Further, when near-infrared light enters, near-infrared light is detected at the first PN junction. Therefore, it is possible to provide an in-vehicle color sensor that can easily cope with not only visible light sensing but also near infrared light sensing.

  (6) Here, as shown in FIG. 17, a P-type fourth impurity diffusion region 94 shallower than the impurity diffusion region 93 is further formed in the surface layer portion of the silicon substrate 90 in the third impurity diffusion region 93. Since the shallowest fourth PN junction for photoelectrically converting blue light is formed at the interface between the bottom surface of the impurity diffusion region 94 and the impurity diffusion region 93, blue light can be detected.

In addition, you may change the said embodiment as follows.
Basic 4 pixels are visible red (R), green (G), green (G), near infrared (IR), and basic 4 pixels are visible red (R), green (G), blue ( B) The near infrared region (IR) is used. However, the present invention is not limited to this, and red (R), green (G), and near infrared region (IR) in the visible region may be formed with three basic pixels.

  In addition, as described above, the on-vehicle color sensor has been described with respect to the light control device, the raindrop sensor (night monitoring camera), etc., but is not limited thereto, and other systems for sensing light in the visible region and the near infrared region. You may apply to the system which senses light.

The schematic block diagram of the vehicle light control apparatus in this embodiment. The block diagram of the optical system of the vehicle-mounted color sensor in this embodiment. The perspective view of the image sensor with a cover glass of the vehicle-mounted color sensor. (A) is a top view of the image sensor with a cover glass of the vehicle-mounted color sensor in 1st Embodiment, (b) is a longitudinal cross-sectional view in the AA line of (a), (c) is (a). The longitudinal cross-sectional view in the BB line. (A) is a plan view of an image sensor of an in-vehicle color sensor, (b) is a longitudinal sectional view taken along line AA in (a), and (c) is a longitudinal sectional view taken along line BB in (a). . FIG. 5A is a plan view of an image sensor of an in-vehicle color sensor with the filter removed from FIG. 5, FIG. 5B is a longitudinal sectional view taken along line AA in FIG. 5A, and FIG. The longitudinal cross-sectional view in the BB line. The figure which shows the advancing direction ahead of a vehicle. The figure which shows the image after a process. (A) is a top view of the image sensor with a cover glass of the vehicle-mounted color sensor in 2nd Embodiment, (b) is a longitudinal cross-sectional view in the AA line of (a), (c) is (a). The longitudinal cross-sectional view in the BB line. (A) is a top view of the image sensor with a cover glass of the vehicle-mounted color sensor in 3rd Embodiment, (b) is a longitudinal cross-sectional view in the AA line of (a), (c) is (a). The longitudinal cross-sectional view in the BB line. (A) is a top view of the image sensor with a cover glass of the vehicle-mounted color sensor in 4th Embodiment, (b) is a longitudinal cross-sectional view in the AA line of (a), (c) is (a). The longitudinal cross-sectional view in the BB line. Sectional drawing of the image sensor with a cover glass of the vehicle-mounted color sensor in 5th Embodiment. (A)-(e) is sectional drawing which shows the manufacturing process of the vehicle-mounted color sensor in 5th Embodiment. (A)-(d) is sectional drawing which shows the manufacturing process of the vehicle-mounted color sensor in 5th Embodiment. (A), (b) is sectional drawing which shows the manufacturing process of the vehicle-mounted color sensor in 5th Embodiment. Sectional drawing which shows the manufacturing process of the vehicle-mounted color sensor in 5th Embodiment. Sectional drawing of the image pick-up element of the vehicle-mounted color sensor in 6th Embodiment. Sectional drawing of the image pick-up element of the vehicle-mounted color sensor in 6th Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Board | substrate, 20 ... Light receiving element, 21 ... Light receiving element, 22 ... Light receiving element, 23 ... Light receiving element, 24 ... Light receiving element, 25 ... Light receiving element, 30 ... Red filter, 31 ... Green filter, 32 ... Green filter, 34 ... Blue filter, 40 ... Near infrared light cut filter, 41 ... Near infrared light cut filter, 42 ... Near infrared light cut filter, 43 ... Visible light cut filter, 44 ... Near infrared light cut filter, 50 ... UV Cut glass plate, 60 ... Visible light curable adhesive, 72 ... SOG film, 73 ... Electrode pad, 75 ... Thin film for near infrared light cut filter, 77 ... Thin film for visible light cut filter, 90 ... P-type silicon substrate, 91 ... N-type impurity diffusion region, 92 ... P-type impurity diffusion region, 93 ... N-type impurity diffusion region, 94 ... P-type impurity diffusion region.

Claims (12)

A substrate (10);
A plurality of light receiving elements (20, 21, 22, 23) that are arranged on the upper surface of the substrate (10) and output an electrical signal corresponding to the amount of light in the ultraviolet region, visible region, and near infrared region;
A first near-infrared light cut filter (40) disposed on a first light receiving element (20) of the adjacent light receiving elements via a red filter (30) that selectively allows red light to pass therethrough. )When,
Second near-infrared light disposed on the second light-receiving element (21, 22) of the adjacent light-receiving elements via a green filter (31, 32) that selectively transmits green light. A cut filter (41, 42);
A visible light cut filter (43) disposed on a third light receiving element (23) of the adjacent light receiving elements;
An ultraviolet cut glass plate (50) disposed on the first near infrared light cut filter (40), the second near infrared light cut filter (41, 42) and the visible light cut filter (43); ,
An in-vehicle color sensor comprising: The in-vehicle color sensor according to claim 1,
The first near-infrared light cut filter (40) and the second near-infrared light cut filter (41, 42) are on-vehicle color sensors formed on the lower surface of the ultraviolet cut glass plate (50). The in-vehicle color sensor according to claim 2,
A vehicle-mounted color sensor in which a visible light curable adhesive (60) is interposed between the substrate (10) and the ultraviolet cut glass plate (50). The in-vehicle color sensor according to claim 1,
A third near-infrared light cut filter (44) disposed on a fourth light receiving element (24) among the adjacent light receiving elements via a blue filter (34) that selectively transmits blue light. ), An in-vehicle color sensor. The in-vehicle color sensor according to claim 1,
The light receiving elements (25) arranged on the substrate (10) other than the first to third light receiving elements receive light through the ultraviolet cut glass plate (50) without passing through color filters or cut filters. An in-vehicle color sensor. The in-vehicle color sensor according to claim 1 or 2,
The first near-infrared light cut filter (40), the second near-infrared light cut filter (41, 42), and the visible light cut filter (43) are in-vehicle color sensors made of a thin film. A first conductivity type first impurity diffusion region (91) is formed in the surface layer portion of the first conductivity type silicon substrate (90) to be the first conductivity type impurity diffusion region, and the first impurity diffusion In the region (91), a second impurity diffusion region (92) of the first conductivity type shallower than the first impurity diffusion region (91) is formed in the surface layer portion of the silicon substrate (90). In the impurity diffusion region (92), a third impurity diffusion region (93) of the second conductivity type shallower than the second impurity diffusion region (92) is formed in the surface layer portion of the silicon substrate (20).
A deepest first PN junction for photoelectrically converting near-infrared light is formed at the interface between the bottom surface of the first impurity diffusion region (91) and the silicon substrate (90). A second deepest second PN junction for photoelectrically converting red light at the interface between the bottom surface of the second impurity diffusion region (92) and the first impurity diffusion region (91); The third deepest third PN junction for photoelectrically converting green light at the interface between the bottom surface of the third impurity diffusion region (93) and the second impurity diffusion region (92). In-vehicle color sensor. The in-vehicle color sensor according to claim 7,
In the third impurity diffusion region (93), a fourth impurity diffusion region (94) of the first conductivity type shallower than the third impurity diffusion region (93) is further formed on the surface layer portion of the silicon substrate (90). The shallowest fourth PN junction for photoelectrically converting blue light is formed at the interface between the bottom surface of the fourth impurity diffusion region (94) and the third impurity diffusion region (93). An in-vehicle color sensor. It is a manufacturing method of the color sensor for vehicles according to claim 6,
A large number of light receiving elements (20, 21, 22, 23) are arranged on the upper surface of the substrate (10), a red filter (30) is provided on the first light receiving element (20), and a second light receiving element is provided. A first step of forming a green filter (31, 32) on (21, 22);
A second step of forming an SOG film (72) on the entire surface of the substrate (70) including the red filter (30) and the green filter (31, 32);
A third step of patterning a thin film (75) for a near-infrared light cut filter on the SOG film (72) and patterning a thin film (77) for a visible light cut filter on the SOG film (72); ,
The manufacturing method of the color sensor for vehicle mounting characterized by including. In the manufacturing method of the vehicle-mounted color sensor of Claim 9,
In the first step, an electrode pad (73) is formed on the upper surface of the substrate (70), and after the third step, the SOG film (72) on the electrode pad (73) is removed to form the electrode pad (73). A method for manufacturing an in-vehicle color sensor including the exposed fourth step. In the manufacturing method of the in-vehicle color sensor according to claim 9 or 10,
A thin film (75) for a near-infrared light cut filter in the third step is a method for manufacturing an on-vehicle color sensor formed by vapor deposition. In the manufacturing method of the vehicle-mounted color sensor of any one of Claim 9,10,11,
The method for manufacturing an in-vehicle color sensor, wherein the visible light cut filter thin film (77) in the third step is formed by vapor deposition.

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