JP2008218755A - Photoelectric conversion device and image pickup system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric conversion device and an image pickup system capable of reducing a difference of a dark current between an effective pixel region and an optical black pixel region. <P>SOLUTION: The photoelectric conversion device of a first aspect of this invention having the effective pixel region for outputting a pixel signal and the optical black pixel region for outputting a black reference signal comprises a photoelectric converting unit; a light-shielding layer provided over the photoelectric converting unit and having area per pixel different in the effective pixel region and the optical black pixel region; and a first material layer arranged along a lower surface of the light-shielding layer respectively in the effective pixel region and the optical black pixel region, and formed by a first material having a reflection coefficient lower than that of the light-shielding layer and a hydrogen storage capability higher than that of the light-shielding layer. The area per unit pixel of the first material layer is smaller than that of the light-shielding layer in the optical black pixel region. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a photoelectric conversion device and an imaging system.

  In a photoelectric conversion device in which pixels (unit pixels) are arranged one-dimensionally or two-dimensionally, an effective pixel region for outputting a pixel signal and an optical black pixel region for outputting a black reference signal may be provided. The optical black pixel region is covered with a light shielding layer and has a structure that does not allow light to enter.

  Under the light shielding layer, the wiring layer may be connected to a via plug or a contact plug through a barrier metal layer. In addition, the via plug may be connected to the wiring layer through the barrier metal layer. The contact plug may be connected to the semiconductor region of the substrate through the barrier metal layer.

  Ti which is the main component of these barrier metal layers has a lower reflectance than Al which is the main component of the wiring layer. Therefore, since the barrier metal layer is formed under the light shielding layer, it functions as a low reflection film that prevents multiple reflection of light incident under the light shielding layer. Thereby, the smear of a photoelectric conversion apparatus can be reduced.

  On the other hand, Ti, which is the main component of the barrier metal layer, has a higher hydrogen storage effect than Al, which is the main component of the wiring layer. Therefore, the barrier metal layer occludes hydrogen during hydrogen annealing and may weaken the hydrogen termination effect (hydrogen annealing effect) in the vicinity of the Si—SiO 2 interface. This may increase the dark current.

  On the other hand, in the technique disclosed in Patent Document 1, the low reflection film having a high hydrogen storage effect is partially opened in a region where dark current is particularly problematic (a part above the vertical transfer register of the CCD). ing. As a result, an increase in dark current is reduced in a region where dark current is particularly problematic.

Further, in the technique disclosed in Patent Document 2, a titanium-based antireflection film and a titanium-based barrier metal layer are formed, and hydrogen is supplied to the titanium-based antireflection film and the titanium-based barrier metal layer, so that the titanium-based reflection is performed. The prevention film and the titanium-based barrier metal layer are in a hydrogen supersaturated state. Thereby, the hydrogen occlusion effect of the titanium-based antireflection film and the titanium-based barrier metal layer is weakened, and the increase in dark current is reduced.
Japanese Patent Laid-Open No. 06-260628 Japanese Patent Application Laid-Open No. 07-094692

  In the techniques disclosed in Patent Document 1 and Patent Document 2, the effective pixel area and the optical black pixel area tend to have different areas per unit pixel of the titanium layer. As a result, the hydrogen annealing effect differs between the effective pixel region and the optical black pixel region, and a dark current difference may occur.

  The objective of this invention is providing the photoelectric conversion apparatus and imaging system which can reduce the dark current difference of an effective pixel area | region and an optical black pixel area | region.

  A photoelectric conversion device according to a first aspect of the present invention is a photoelectric conversion device having an effective pixel region for outputting a pixel signal and an optical black pixel region for outputting a black reference signal, wherein the photoelectric conversion unit In each of the effective pixel region and the optical black pixel region, a light-shielding layer provided above the photoelectric conversion unit and having different areas per unit pixel in the effective pixel region and the optical black pixel region. A first material layer formed along a lower surface of the light shielding layer and formed of a first material having a lower reflectance than the light shielding layer and a higher hydrogen storage capacity than the light shielding layer; The area per unit pixel of the material layer is smaller than the area per unit pixel of the light shielding layer in the optical black pixel region.

  An imaging system according to a second aspect of the present invention processes a photoelectric conversion device according to the first aspect of the present invention, an optical system for imaging light onto the photoelectric conversion device, and a signal output from the photoelectric conversion device. And a signal processing unit for generating image data.

  According to the present invention, the dark current difference between the effective pixel region and the optical black pixel region can be reduced.

  In the present specification, the present invention will be described in detail with reference to embodiments. However, the present invention is not limited to these embodiments, can be modified as appropriate, and may be a combination of a plurality of embodiments. In this specification, “upper” and “lower” refer to a main surface on which a device is arranged on a semiconductor substrate as a reference, the substrate deep direction as the “down” direction, and the opposite direction as the “upper” direction. To do.

Note that a substrate that is a material substrate is expressed as a “substrate”, but such a material substrate is processed to form, for example, a member in which one or a plurality of semiconductor regions and the like are formed, or a series of manufacturing steps. A member in the middle or a member that has undergone a series of manufacturing steps can also be called a substrate.
A photoelectric conversion device 1 according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view showing the structure of the photoelectric conversion device according to the first embodiment of the present invention.

  The photoelectric conversion apparatus 1 is used for a digital camera, a video camera, a copying machine, a facsimile, and the like, for example. As shown in FIG. 1, the photoelectric conversion device 1 includes an effective pixel region 111 and an optical black pixel region (hereinafter referred to as an OB pixel region) 112.

  The effective pixel region 111 includes a plurality of pixels (unit pixels) for outputting an image signal (pixel signal) to a horizontal scanning circuit (not shown). In the effective pixel region 111, light is incident on the photodiode (photoelectric conversion unit) PD, and the light is incident on a transistor (for example, an amplification MOS transistor (not shown)).

  The OB pixel region 112 includes a plurality of pixels (unit pixels) for outputting a black gradation reference signal (black reference signal) by a horizontal scanning circuit (not shown).

  The basic configuration of the pixels in the effective pixel region 111 and the pixels in the OB pixel region 112 are the same. That is, the pixel (unit pixel) includes a semiconductor region 101, a semiconductor region 102, a transfer MOS transistor 103, a floating diffusion region (hereinafter referred to as FD region) 104, and a contact plug 105. The pixel includes a first wiring layer 106, a first via plug 107, a second wiring layer 108, a second via plug 109, a third wiring layer 110, and a passivation film (upper layer) 113.

  The semiconductor region 101 is a first conductivity type (for example, P-type) semiconductor region.

  The semiconductor region 102 is a semiconductor region of a second conductivity type (for example, N type) that is opposite to the first conductivity type. Here, the semiconductor region 101 and the semiconductor region 102 form a PN junction in the vicinity of the boundary thereof to constitute a photodiode PD that functions as a photoelectric conversion unit. When the second conductivity type charge is a carrier, the semiconductor region 102 accumulates the charge.

  The transfer MOS transistor 103 transfers the charge accumulated in the semiconductor region 102 of the photodiode PD to the FD region 104 when a signal for activation is supplied to the gate.

  The FD region 104 is a second conductivity type semiconductor region, and charges are transferred from the photodiode PD via the transfer MOS transistor 103. The FD region 104 also functions as a drain region of the transfer MOS transistor 103.

  The contact plug 105 connects the FD region 104 and the first wiring layer 106.

  The first wiring layer 106 is connected to the second wiring layer 108 via the first via plug 107.

  The second wiring layer 108 is connected to the third wiring layer 110 via the second via plug 109.

  Here, the first wiring layer 106, the second wiring layer 108, and the third wiring layer 110 (the core layer described later) function as a light shielding layer. In the pixels of the effective pixel region 111, the wiring layers 106, 108, 110 above the photodiode PD are opened. On the other hand, in the pixel in the OB pixel region 112, the upper side of the photodiode PD is also covered with the wiring layers 106, 108, and 110. In this respect, the pixels in the effective pixel region 111 and the pixels in the OB pixel region 112 are different.

  The passivation film 113 extends through the effective pixel region 111 and the OB pixel region 112 along the upper surface of the third wiring layer 110 including a core layer (light shielding layer) described later. The passivation film 113 is made of, for example, silicon nitride. The passivation film 113 can contain hydrogen, and can diffuse hydrogen during heat treatment to repair defects at the Si-SiO oxide film interface. That is, the passivation film 113 functions as a hydrogen supply layer. The passivation film 113 is formed on the entire surface of the effective pixel region 111 and the OB pixel region 112. Accordingly, the titanium layer and the titanium nitride layer can be uniformly hydrogen supersaturated in the effective pixel region 111 and the OB pixel region 112 without separately performing a long-time plasma treatment.

  Note that the passivation film 113 may be removed after the hydrogen annealing treatment. By removing the passivation film 113, it becomes easy to match the refractive index in the optical path, and the incidence rate of light on the photoelectric conversion unit can be improved.

  Next, detailed configurations of the second via plug 109 and the third wiring layer 110 will be described with reference to FIG. FIG. 2 is an enlarged cross-sectional view of the broken line region 114 of FIG.

  The second via plug 109 includes a first barrier metal layer 109a and a core layer 109b.

  The first barrier metal layer 109 a includes a titanium layer 201 and a titanium nitride layer 202. The titanium layer 201 is formed so as to cover the titanium nitride layer 202. The titanium layer (first material layer) 201 is formed of titanium (first material). The titanium nitride layer 202 is formed so as to cover the core layer 109b. The titanium nitride layer 202 is formed of titanium nitride (second material).

  Here, the titanium layer 201 is formed of titanium (first material) having a lower reflectance than an aluminum alloy layer (light-shielding layer) 205 described later and a higher hydrogen storage capacity than the aluminum alloy layer (light-shielding layer) 205. Yes.

  The core layer 109b includes a tungsten layer 203. The tungsten layer 203 is formed so as to be embedded in the recessed portion of the titanium nitride layer 202. The tungsten layer 203 is made of tungsten.

  On the other hand, the third wiring layer 110 includes a second barrier metal layer 110a and a core layer 110b.

  The second barrier metal layer 110 a includes a titanium nitride layer 204 and a titanium nitride layer 206. The titanium nitride layer 204 extends along the lower surface of the core layer 110b. The titanium nitride layer 204 is also formed between the second via plug 109 and the core layer 110b. The titanium nitride layer 204 is made of titanium nitride. The titanium nitride layer 206 is formed on the core layer 110b. The titanium nitride layer 206 is formed of titanium nitride.

  The core layer 110b functions as a light shielding layer. The core layer 110b includes an aluminum alloy layer 205. Aluminum alloy layer 205 is formed on titanium nitride layer 204. The aluminum alloy layer 205 is formed of an aluminum alloy containing aluminum as a main component.

  Here, the second via plug 109 and the third wiring layer 110 are common in that the core layer is sandwiched between barrier metal layers. However, the second via plug 109 includes a titanium layer, but the third wiring layer 110 is different in that it does not include a titanium layer. That is, the titanium layer having a high hydrogen storage effect is provided only in the connection region of the plug, and is not provided on the entire lower surface of the light shielding layer.

  Note that a layer formed of titanium is not disposed below the third wiring layer 110 disposed in the effective pixel region 111, but a layer formed of titanium may be partially disposed. . The configuration of the first wiring layer 106 and the second wiring layer 108 is basically the same as that of the third wiring layer 110, except that a titanium layer is formed along the lower surface of the titanium nitride layer. Is different. That is, in the first wiring layer 106 and the second wiring layer 108, the titanium layer is disposed along the lower surface of the core layer. A titanium nitride layer is disposed between the core layer and the titanium layer along the lower surface of the core layer.

  Thus, in the OB pixel region 112, the area per unit pixel of the titanium layer is (relatively) smaller than the area per unit pixel of the light shielding layer. Thereby, the area per unit pixel of the titanium layer can be made substantially the same in the effective pixel region and the OB pixel region having different areas per unit pixel of the light shielding layer. For this reason, it is possible to reduce the difference in the degree of the hydrogen annealing effect (hydrogen sintering effect) between the effective pixel region and the OB pixel region, and it is possible to reduce the dark current difference.

  Next, a photoelectric conversion device 300 according to a comparative example will be described with reference to FIGS. FIG. 3 is a cross-sectional view illustrating a structure of a photoelectric conversion device 300 according to a comparative example. FIG. 4 is an enlarged cross-sectional view of the broken line region 301 of FIG. 1 and 2 will be mainly described, and description of similar parts will be omitted.

  As shown in FIG. 3, the pixel of the photoelectric conversion device 300 according to the comparative example includes a contact plug 305, a first wiring layer 306, a first via plug 307, a second wiring layer 308, a second via plug 309, 3 is different from that of FIGS. 1 and 2.

  For example, as shown in FIG. 4, the second via plug 309 includes a core layer 309b. The core layer 309b includes a tungsten layer 403. The tungsten layer 403 extends from the recessed portion of the titanium nitride layer 202 to the core layer 110 b of the third wiring layer 310.

  On the other hand, the third wiring layer 310 includes a third barrier metal layer 310c. The third barrier metal layer 310 c includes a titanium layer 404 and a titanium nitride layer 405. The titanium layer 404 extends over almost the entire lower surface of the third wiring layer 310. The titanium layer 404 is made of titanium.

  In this case, in the OB pixel region 112, the area per unit pixel of the titanium layer is substantially the same as the area per unit pixel of the light shielding layer. This makes it difficult to make the area per unit pixel of the titanium layer substantially the same between the effective pixel region and the OB pixel region having different areas per unit pixel of the light shielding layer. For this reason, it is difficult to reduce the difference in the degree of the hydrogen annealing effect (hydrogen sintering effect) between the effective pixel region and the OB pixel region, and it is difficult to reduce the dark current difference. This causes a difference between the black level of the actual image and the black level of the OB pixel area, resulting in a deteriorated image such as a color cast.

  Such a phenomenon occurs because the area per unit pixel of the titanium layer having a high hydrogen storage effect is different between the effective pixel region and the OB pixel region. By making the area per unit pixel of the titanium layer substantially the same, it becomes possible to reduce the dark current difference between the effective pixel region and the OB pixel region, and good image quality can be obtained.

  Next, a method for manufacturing the photoelectric conversion device illustrated in FIG. 1 will be described.

  First, a semiconductor substrate 101 made of a silicon wafer or the like is prepared, and an element isolation region 115 is formed on the semiconductor substrate 101 by a LOCOS method or the like. Next, a photoresist pattern is formed, ion implantation and heat treatment are performed, and a semiconductor region 102 for forming a photodiode, for example, is formed in the semiconductor substrate 101.

  Then, in order to form a transistor including the transfer MOS transistor 103, an SiO 2 film 116 is formed on the surface of the semiconductor substrate 101, and an electrode 117 made of polycrystalline silicon is formed on the SiO 2 film 116. Subsequently, a photoresist pattern is formed, and ion implantation and heat treatment are performed to form, for example, an FD region 104 serving as a drain region of the transfer MOS transistor 103 in the semiconductor substrate 101.

  Next, the first insulating film 118 is formed on the effective pixel region 111, the OB pixel region 112, and a peripheral circuit region (not shown) for driving these by the CVD method or the like, and the surface is flattened by CMP or the like. To do.

  Next, a photoresist pattern is formed and etched to form a contact hole in a region corresponding to the contact plug 105 of the first insulating film 118.

  Subsequently, titanium and titanium nitride are formed on the contact holes and the surface of the first insulating film 118 by sputtering, CVD, or the like. Next, tungsten is formed by sputtering, CVD, or the like. The contact plug 105 is formed by polishing tungsten, titanium nitride, and titanium until the surface of the first insulating film 118 is exposed by a CVD method or the like.

  Next, in order to form the first wiring layer 106, titanium nitride is formed on the first insulating film 118 by sputtering, CVD, or the like, and an aluminum alloy containing aluminum and copper is formed thereon. To do. Then, a titanium nitride film is formed, a photoresist pattern is formed, and etching is performed to form the first wiring layer 106 having a desired pattern.

  Next, a second insulating film 119 is formed on the entire surface, and the surface is planarized by CMP or the like. A photoresist pattern is formed and etched to form a via hole in a region corresponding to the first via plug 107 of the second insulating film. Subsequently, titanium and then titanium nitride are formed on the surface of the via hole and the second insulating film 119 by sputtering, CVD, or the like. Tungsten is formed by sputtering, CVD, or the like.

  Next, tungsten, titanium nitride, and titanium are polished by CMP or the like until the surface of the second insulating film 119 is exposed, so that the first via plug 107 is formed.

  Next, in order to form the second wiring layer 108, titanium nitride is formed over the second insulating film 119 by sputtering, a CVD method, or the like. An aluminum alloy film is formed in the same manner as the first wiring layer. Subsequently, a titanium nitride film is formed, a photoresist pattern is formed, and etching is performed to form the second wiring layer 108 having a desired pattern.

  Next, a third insulating film 120 is formed on the entire surface, and the surface is planarized by CMP or the like. A photoresist pattern is formed and etching is performed to form a via hole in a region corresponding to the second via plug 109 of the third insulating film 120.

  Subsequently, titanium and titanium nitride are formed on the surface of the via hole and the third insulating film 120 by sputtering, CVD, or the like, and tungsten is formed by sputtering, CVD, or the like. Then, the second via plug 109 is formed by polishing tungsten, titanium nitride, and titanium until the surface of the third insulating film 120 is exposed by CMP or the like.

  Next, in order to form the third wiring layer 110, titanium nitride is formed on the third insulating film 120 by sputtering, CVD, or the like. An aluminum alloy film is formed in the same manner as the first and second wiring layers 106 and 108, and titanium nitride is formed. Then, a third wiring layer 110 having a desired pattern is formed by forming and etching a photoresist pattern.

  Next, a passivation film 113 functioning as a hydrogen supply layer is formed on the entire surface of the third wiring layer 110 by a CVD method or the like using a silicon nitride film. Thereby, the photoelectric conversion apparatus 1 shown in FIG. 1 is formed.

  As described above, in the OB pixel region 112, the area per unit pixel of the titanium layer is (relatively) smaller than the area per unit pixel of the light shielding layer. Thereby, the area per unit pixel of the titanium layer can be made substantially the same between the effective pixel region and the OB pixel region having different areas per unit pixel of the light shielding layer. For this reason, the difference in hydrogen storage effect between the effective pixel region and the OB pixel region can be reduced, and the difference in the degree of the hydrogen annealing effect (hydrogen sintering effect) can be reduced. As a result, the dark current difference between the effective pixel region 111 and the OB pixel region 112 can be reduced, and a photoelectric conversion device having a high S / N ratio can be provided.

  The passivation film 113 is formed on the entire surface of the effective pixel region 111 and the OB pixel region 112. Thereby, the titanium layer and the titanium nitride layer are uniformly hydrogen supersaturated in the effective pixel region 111 and the OB pixel region 112 without performing a separate long-time plasma treatment as in the technique disclosed in Patent Document 2. Can be in a state. As a result, the dark current difference between the effective pixel region 111 and the OB pixel region 112 can be reduced at a low cost.

  Next, an example of an imaging system to which the photoelectric conversion device 1 according to the first embodiment is applied will be described with reference to FIG. FIG. 8 is a configuration diagram of an imaging system to which the photoelectric conversion device 1 according to the first embodiment is applied.

  As shown in FIG. 8, the imaging system 90 mainly includes an optical system, an imaging device 86, and a signal processing unit. The optical system mainly includes a shutter 91, a photographing lens 92, and a diaphragm 93. The imaging device 86 includes the photoelectric conversion device 1. The signal processing unit mainly includes an imaging signal processing circuit 95, an A / D converter 96, an image signal processing unit 97, a memory unit 87, an external I / F unit 89, a timing generation unit 98, an overall control / calculation unit 99, and a recording. A medium 88 and a recording medium control I / F unit 94 are provided. The signal processing unit may not include the recording medium 88.

  The shutter 91 is provided in front of the photographic lens 92 on the optical path and controls exposure.

  The photographic lens 92 refracts the incident light and forms an image of the subject on the photoelectric conversion device 1 of the imaging device 86.

  The diaphragm 93 is provided between the photographing lens 92 and the photoelectric conversion device 1 on the optical path, and adjusts the amount of light guided to the photoelectric conversion device 1 after passing through the photographing lens 92.

  The photoelectric conversion device 1 of the imaging device 86 converts the subject image formed on the photoelectric conversion device 1 into an image signal. The imaging device 86 reads the image signal from the photoelectric conversion device 1 and outputs it.

  The imaging signal processing circuit 95 is connected to the imaging device 86 and processes the image signal output from the imaging device 86.

  The A / D converter 96 is connected to the imaging signal processing circuit 95 and converts the processed image signal (analog signal) output from the imaging signal processing circuit 95 into a digital signal.

  The image signal processing unit 97 is connected to the A / D converter 96, and performs various kinds of arithmetic processing such as correction on the image signal (digital signal) output from the A / D converter 96 to generate image data. To do. The image data is supplied to the memory unit 87, the external I / F unit 89, the overall control / calculation unit 99, the recording medium control I / F unit 94, and the like.

  The memory unit 87 is connected to the image signal processing unit 97 and stores the image data output from the image signal processing unit 97.

  The external I / F unit 89 is connected to the image signal processing unit 97. Thus, the image data output from the image signal processing unit 97 is transferred to an external device (such as a personal computer) via the external I / F unit 89.

  The timing generation unit 98 is connected to the imaging device 86, the imaging signal processing circuit 95, the A / D converter 96, and the image signal processing unit 97. Thereby, a timing signal is supplied to the imaging device 86, the imaging signal processing circuit 95, the A / D converter 96, and the image signal processing unit 97. The imaging device 86, the imaging signal processing circuit 95, the A / D converter 96, and the image signal processing unit 97 operate in synchronization with the timing signal.

  The overall control / arithmetic unit 99 is connected to the timing generation unit 98, the image signal processing unit 97, and the recording medium control I / F unit 94, and the timing generation unit 98, the image signal processing unit 97, and the recording medium control I / F. The unit 94 is controlled as a whole.

  The recording medium 88 is detachably connected to the recording medium control I / F unit 94. As a result, the image data output from the image signal processing unit 97 is recorded on the recording medium 88 via the recording medium control I / F unit 94.

  With the above configuration, if a good image signal is obtained in the photoelectric conversion device 1, a good image (image data) can be obtained.

  Next, a photoelectric conversion device 500 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view showing the structure of a photoelectric conversion device 500 according to the second embodiment of the present invention. In addition, it demonstrates centering on a different part from 1st Embodiment, and abbreviate | omits description about the same part.

  The basic structure of the photoelectric conversion device 500 is the same as that of the first embodiment, but the structures of the first wiring layer 506, the second wiring layer 508, and the third wiring layer 510 are different from those of the first embodiment. . That is, a titanium layer is formed on a part of the lower surface of the light shielding layer (the first wiring layer 506, the second wiring layer 508, and the third wiring layer 510). This titanium layer has substantially the same pattern in the effective pixel region and the OB pixel region.

  Note that, in the OB pixel region 112, the area per unit pixel of the titanium layer is (relatively) smaller than the area per unit pixel of the light shielding layer, as in the first embodiment.

  Moreover, the manufacturing method of the photoelectric conversion apparatus 500 is different from the first embodiment in the following points.

  In order to form the first wiring layer 506, titanium and titanium nitride are formed over the first insulating film 118 by sputtering, a CVD method, or the like. Next, an aluminum alloy is formed, and titanium nitride is formed. Then, a first wiring layer 506 having a desired pattern is formed by forming and etching a photoresist pattern.

  Next, in order to form the second wiring layer 508, titanium and titanium nitride are formed over the second insulating film 119 by sputtering, a CVD method, or the like. An aluminum alloy is deposited, and titanium nitride is deposited. Then, a second wiring layer 508 having a desired pattern is formed by forming and etching a photoresist pattern.

  Then, titanium is formed on the third insulating film 120 by sputtering, a CVD method, or the like. Patterning is performed so that the formed titanium has the same shape in the effective pixel region 111 and the OB pixel region 112. Titanium nitride is formed by sputtering, CVD, or the like, an aluminum alloy is formed, and titanium nitride is formed. Next, a third wiring layer 510 having a desired pattern is formed by forming and etching a photoresist pattern.

  Next, a photoelectric conversion device 600 according to a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view showing the structure of a photoelectric conversion device 600 according to the third embodiment of the present invention. In addition, it demonstrates centering on a different part from 2nd Embodiment, and abbreviate | omits description about the same part.

  The basic structure of the photoelectric conversion device 600 is the same as that of the second embodiment, but the structure of the third wiring layer 610 is different from that of the second embodiment. That is, the titanium layer is not formed on the lower surface of the third wiring layer 610 (first light shielding layer). Thereby, compared with 2nd Embodiment, the deposition process of the titanium and titanium nitride with respect to the 3rd wiring layer 610 can be skipped, and manufacturing cost can be reduced.

  In particular, since the third wiring layer 610 may be used for wiring for supplying a power supply or ground potential, a relatively fine pattern is required as compared with the other wiring layers (second light shielding layers) 506 and 508. do not do. Therefore, the step of forming the barrier metal layer can be omitted. The other wiring layers 506 and 508 are provided with a barrier metal layer because fine pattern accuracy is required. Thereby, a fine pattern can be formed.

  Note that, in the OB pixel region 112, the area per unit pixel of the titanium layer is (relatively) smaller than the area per unit pixel of the light shielding layer, as in the second embodiment.

  Moreover, the manufacturing method of the photoelectric conversion apparatus 600 is different from the second embodiment in the following points.

  After the formation of the second via plug 109, an aluminum alloy film is formed on the third insulating film 120 by sputtering, CVD, or the like to form titanium nitride. Then, a third wiring layer 610 having a desired pattern is formed by forming and etching a photoresist pattern.

  Next, a photoelectric conversion device 700 according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional view showing the structure of a photoelectric conversion device 700 according to the fourth embodiment of the present invention. In addition, it demonstrates centering on a different part from 3rd Embodiment, and abbreviate | omits description about the same part.

  The basic structure of the photoelectric conversion device 700 is the same as that of the third embodiment, but the structure of the second via plug 709 is different from that of the third embodiment. That is, the second via plug 709 does not include a barrier metal layer. Thereby, the shape of the titanium layer can be made the same in the effective pixel region 111 and the OB pixel region 112. In addition, the titanium / titanium nitride forming step when forming the second via plug 709 can be omitted, and the manufacturing cost can be further reduced.

  In particular, the third wiring layer 610 may be used for a wiring that supplies a power source or a ground potential, and therefore does not require a relatively fine wiring compared to the other wiring layers 506 and 508. Therefore, since the diameter of the second via plug 709 can be increased, it can be realized by an inexpensive process.

  Moreover, the manufacturing method of the photoelectric conversion apparatus 700 is different from the second embodiment in the following points.

  After the formation of the second wiring layer 508, the third insulating film 120 is formed on the entire surface, and the surface is planarized by CMP or the like. Next, a photoresist pattern is formed and etched to form a via hole in a region corresponding to the second via plug 709 of the second insulating film. Subsequently, an aluminum alloy film is formed by sputtering, CVD, or the like to form titanium nitride. Then, a second via plug 709 and a third wiring layer 610 having a desired pattern are formed simultaneously by forming and etching a photoresist pattern.

Sectional drawing which shows the structure of the photoelectric conversion apparatus which concerns on 1st Embodiment of this invention. The expanded sectional view of the broken-line area | region 114 of FIG. Sectional drawing which shows the structure of the photoelectric conversion apparatus which concerns on a comparative example. The expanded sectional view of the broken-line area | region 301 of FIG. Sectional drawing which shows the structure of the photoelectric conversion apparatus which concerns on 2nd Embodiment of this invention. Sectional drawing which shows the structure of the photoelectric conversion apparatus which concerns on 3rd Embodiment of this invention. Sectional drawing which shows the structure of the photoelectric conversion apparatus which concerns on 4th Embodiment of this invention. 1 is a configuration diagram of an imaging system to which a photoelectric conversion device 1 according to a first embodiment is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Barrier 2 Lens 3 Diaphragm 4 Solid-state image sensor 5 Imaging signal processing circuit 6 A / D converter 7 Signal processing part 8 Timing generation part 9 Overall control and calculation part 10 Memory part 11 Recording medium control interface (I / F) part 12 Recording medium 13 External interface (I / F) unit 101 Semiconductor substrate 102 Photodiode 103 Transfer MOS transistor 104 FD region 105 Contact plug 106 First wiring layer 107 First via plug 108 Second wiring layer 109 Second via plug 110 Third wiring layer 111 Effective pixel region 112 OB pixel region 113 Hydrogen supply layer 114 Connection region 201 between wiring layer and via plug 201 Titanium 202 Titanium nitride 203 Tungsten 204 Titanium nitride 205 Alloy 206 mainly composed of aluminum 206 Titanium nitride 301 Wiring layer Via plug Connection region 302 Hydrogen supply layer 401 Titanium 402 Titanium nitride 403 Tungsten 404 Titanium 405 Titanium nitride 406 Alloy mainly composed of aluminum 407 Titanium nitride 501 Titanium 502 disposed in the effective pixel region Titanium 701 disposed in the optical black region Effective Via plug 702 in the pixel area Via plug in the optical black area

Claims (7)

A photoelectric conversion device having an effective pixel region for outputting a pixel signal and an optical black pixel region for outputting a black reference signal,
A photoelectric conversion unit;
A light-shielding layer provided above the photoelectric conversion unit and having different areas per unit pixel in the effective pixel region and the optical black pixel region;
In each of the effective pixel region and the optical black pixel region, a first material that is disposed along the lower surface of the light shielding layer and has a lower reflectance than the light shielding layer and a higher hydrogen storage capacity than the light shielding layer. A formed first material layer;
With
The photoelectric conversion device according to claim 1, wherein an area per unit pixel of the first material layer is smaller than an area per unit pixel of the light shielding layer in the optical black pixel region. In the optical black pixel region, at least a part of the optical black pixel region is disposed between the light shielding layer and the first material layer along the lower surface of the light shielding layer, and has a second hydrogen storage capability lower than that of the first material layer. A second material layer formed of the material of
2. The photoelectric conversion according to claim 1, wherein an area per unit pixel of the first material layer is smaller than an area per unit pixel of the second material layer in the optical black pixel region. apparatus. The area per unit pixel of the first material layer in the effective pixel region is equal to the area per unit pixel of the first material layer in the optical black pixel region. The photoelectric conversion device described. 3. The photoelectric conversion device according to claim 1, wherein a pattern shape of the first material layer in the effective pixel region is equal to a pattern shape of the first material layer in the optical black pixel region. 5. The liquid crystal display device according to claim 1, further comprising an upper layer that extends along the upper surface of the light shielding layer along the effective pixel region and the optical black pixel region and can contain hydrogen. The photoelectric conversion device according to item. A photoelectric conversion device having an effective pixel region for outputting a pixel signal and an optical black pixel region for outputting a black reference signal,
A photoelectric conversion unit;
A first light-shielding layer provided above the photoelectric conversion unit and having different areas per unit pixel between the effective pixel region and the optical black pixel region;
A second light-shielding layer disposed between the photoelectric conversion unit and the first light-shielding layer;
Each of the effective pixel region and the optical black pixel region is disposed along the lower surface of the second light shielding layer, has a lower reflectance than the second light shielding layer, and has a hydrogen occlusion ability than the second light shielding layer. A first material layer formed of a high first material;
The photoelectric conversion device according to claim 1, wherein an area per unit pixel of the first material layer is smaller than an area per unit pixel of the first light shielding layer in the optical black pixel region. The photoelectric conversion device according to any one of claims 1 to 6,
An optical system for imaging light onto the photoelectric conversion device;
A signal processing unit that processes the signal output from the photoelectric conversion device to generate image data;
An imaging system comprising:

Images