JP3586128B2 - Photoelectric conversion element and image sensor - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image sensor used for an image scanner, a facsimile, a video camera, a digital camera, and the like, and a photoelectric conversion element configured therein.
[0002]
[Prior art]
A charge-coupled device (CCD) and an amplifying or non-amplifying solid-state imaging device using a phototransistor or a photodiode are widely used as an electronic eye of an information device such as the image scanner as a line sensor or an area sensor. .
[0003]
In the case of a photoelectric conversion element in which peripheral circuits such as a photoelectric conversion unit (light receiving element) and a signal transfer unit are formed on the same substrate, the light receiving element has a multilayer structure such as an interlayer insulating film and a protective film. When the materials of these layers are different, multiple interference of light occurs due to different refractive indexes. Looking at the spectral sensitivity characteristics of the multilayer structure, ripples are generated, and as a result, the sensitivity of the photoelectric conversion element may be significantly changed due to a slight difference in wavelength.
[0004]
Therefore, if the film thickness of the multilayer film on the light receiving element varies, the spectral sensitivity characteristic shifts according to the film thickness, resulting in a variation in sensitivity to a certain wavelength. This means that in a photoelectric conversion element in which a plurality of light receiving elements are arranged, sensitivity to a certain wavelength in one chip varies.
[0005]
A technique for making the film thickness on the light receiving element uniform is described in JP-A-9-55488. FIG. 16 shows a cross section of such a conventional photoelectric conversion element, wherein 1 is a substrate, 2 is a light receiving element, 3 is a first layer polysilicon gate, 4 is a second layer polysilicon gate, and 5 is a light shielding layer. , 6 are protective films, on which a planarizing layer 7 is provided. Here, the on-chip lens 9 and the color filter 8 are formed on the flattening layer.
[0006]
The flattening layer 7 is formed by forming a flattening precursor layer of an insulating material and then removing the projections by chemical mechanical polishing (CMP). In the CMP process, the running cost of the polishing agent and the polishing pad is high, and the post-polishing cleaning must be performed precisely in order to remove the alkaline polishing agent used for polishing and the polishing debris generated by the polishing. It is a cost process.
[0007]
[Problems to be solved by the invention]
Therefore, in order to form a flat insulating film on the light shielding layer without using the CMP process, an attempt was made to adopt a coating type insulating film using SOG (spin-on-glass).
[0008]
However, since the light-shielding layer serves as a barrier at the time of coating, the thickness of the coating-type insulating film may differ between light-receiving elements on the same chip.
[0009]
For example, as shown in FIG. 17, when the position of the light receiving element is defined by an opening OP defined by the light shielding layer 5, the light shielding layer 5 is interposed between adjacent openings. It is difficult for the flowable precursor of the coating type insulating film to flow over. Therefore, there may be a difference in thickness between the coating type insulating film on the light receiving element near the center of the photoelectric conversion element and the film on the light receiving element near the end of the element. Further, the difference becomes larger on one wafer for producing a plurality of photoelectric conversion elements.
[0010]
Then, such a difference in the thickness of the film will be conspicuously exhibited as a characteristic of the photoelectric conversion element in the following cases.
[0011]
In an image sensor in which a large number of light receiving elements are arranged on a substrate, a color image is read by illuminating a document by sequentially switching red, green, and blue LEDs as light sources in a time series manner. In this case, even if the total film thickness of the multilayer film on the light receiving element is uniform, if the film thickness of each film is different, the spectral sensitivity characteristic is shifted, and the sensitivity distribution curve is different at each wavelength, so that a correct image can be obtained. Can not be.
[0012]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION An object of the present invention is to provide a photoelectric conversion element and an image sensor in which a light-shielding layer does not become a barrier at the time of coating and a difference in the thickness of a coating type insulating film between light-receiving elements on the same chip hardly occurs. is there.
[0013]
The present invention provides a photoelectric conversion element comprising: a plurality of photoelectric conversion units; and a light shielding unit having an opening disposed on the photoelectric conversion unit. The light shielding unit includes a first light shielding layer, a first light shielding layer, and a first light shielding layer. A second light-shielding layer provided on the light-shielding layer with an interlayer insulating film interposed therebetween, and the first light-shielding layer has a gap for communicating two adjacent openings. The light-shielding portion of the second light-shielding layer is arranged on the gap of the first light-shielding layer.
Further, the present invention provides a photoelectric conversion element including: a plurality of photoelectric conversion units; and a light blocking unit having an opening disposed on the photoelectric conversion unit.
A light-shielding conductive layer for wiring; and a conductive light-shielding layer provided on the conductive layer with an interlayer insulating film interposed therebetween. The conductive layer is used to connect two adjacent openings. With a gap of
A light-shielding portion of the conductive light-shielding layer is disposed on the gap between the conductive layers, and is connected to the conductive layer.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a photoelectric conversion element and its components according to an embodiment of the present invention.
[0015]
(A) shows the upper surface of the element, (b) shows the first light-shielding layer, (c) shows the second light-shielding layer, (d) shows a cross section taken along the line AA 'of (a), and (e) shows 3A shows a cross section taken along line BB ′.
[0016]
As shown in FIGS. 1A and 1D, a plurality of photoelectric conversion units (light receiving elements) 2 are provided on a substrate 1, and a first light shielding layer 11 as a light shielding unit is provided above the substrate 1. And a second light-shielding layer 12.
[0017]
As shown in FIG. 1A, the light shielding means has an opening OP on the light receiving element 2 for transmitting light.
[0018]
As shown in FIG. 1B, the first light-shielding layer 11 has a gap GP having a length 11 that connects adjacent openings OP at least in the arrangement direction of the openings.
[0019]
As shown in FIGS. 1 (a), 1 (c) and 1 (e), and over the gap GP of the first light-shielding layer 11, a second light-shielding layer is provided via an interlayer insulating film 13 so as to cover it. Are arranged.
[0020]
According to the photoelectric conversion element of the present embodiment, since the gap GP is provided in the first light shielding layer 11 between the light receiving elements, the precursor to be the interlayer insulating film flows through this gap. Thus, as shown in FIGS. 1D and 1E, variations in the thickness of the interlayer insulating film 13 are suppressed between the light receiving elements, and the thickness becomes uniform.
[0021]
The light shielding portion 12a of the second light shielding layer 12 is disposed on the gap GP so that light does not enter the substrate 1 through the gap GP.
[0022]
On the other hand, assuming that the openings OP are formed independently of each other without providing a gap in the first light shielding layer 11, the cross section between the light receiving elements can be any part between the light receiving elements in FIG. ), And the flow of the precursor is obstructed, and the thicknesses t1 and t2 are different.
[0023]
Examples of the light receiving element 2 used in the present invention include a photodiode or a phototransistor having a Schottky junction, a MIS junction, a PN junction, a PIN junction, or the like. Alternatively, they are physically separated and the individual light receiving elements are isolated.
[0024]
The light-shielding layers 11 and 12 used in the present invention are formed of a pure metal, an alloy, a silicide, or the like. Specifically, a conductor made of a single layer or a laminated body such as Al, AlSi, AlSiCu, AlCu, Cr, Mo, W, WN, Ta, TaN, Ti, and TiN may be used.
[0025]
As the interlayer insulating film used in the present invention, a coating type insulating film using a fluid planarizing precursor such as inorganic SOG or organic SOG is preferably used. Further, if necessary, a multilayer film may be used in combination with an insulating film deposited by a CVD method.
[0026]
Further, a protective film (passivation film) made of silicon nitride or the like may be formed on the second light shielding layer 12 so as to cover the second light shielding layer 12.
[0027]
The length L1 of the gap between the light-shielding layers L1 may be at least 1/3 of the length L2 of the side of the opening OP, and is more preferably at least 1/3 and at most 3/3.
[0028]
FIG. 2 is a plan view of another photoelectric conversion element of the present invention, FIG. 3 is a cross-sectional view taken along line CC ′ of FIG. 2, and FIG. 4 is a cross-sectional view taken along line DD ′ of FIG.
[0029]
As shown in FIG. 2, the photoelectric conversion element has light shielding means having an opening OP on the light receiving element 2.
[0030]
As shown in FIGS. 3 and 4, an element isolation region 15 made of an insulating material formed by selective oxidation or the like, and a light receiving element 2 therebetween are formed on the surface side of a semiconductor substrate 19 such as Si.
[0031]
On the surface of the semiconductor substrate 19, an insulating film 16 for insulating a polysilicon gate electrode (not shown) and a wiring formed thereon is provided. The insulating film 16 is formed of a non-doped silicon oxide film doped with boron (B) or phosphorus (P).
[0032]
As described above, the first light-shielding layer 11 made of Al or the like is formed on the surface of the insulating film 16 by sputtering or the like. The planar pattern of the first light shielding layer 11 has a gap GP between the openings OP as shown in FIG. A part of the wiring of the photoelectric conversion element may be formed using a conductor as the first light shielding layer 11.
[0033]
On the first light shielding layer 11, an interlayer insulating film 13 is provided.
[0034]
First, silicon oxide having good step coverage is deposited to a thickness of about 300 nm to 500 nm by a plasma CVD method. Then, SOG is spin-coated, heat-treated, and then etched back to form a 100-400 nm-thick silicon oxide film (coating type). An interlayer insulating film 13 is formed thereon, and silicon oxide is deposited thereon by plasma CVD to a thickness of 300 to 500 nm to form an interlayer insulating film 13.
[0035]
At the time of spin coating of SOG, the precursor flows on the adjacent light receiving element through the gap GP of the first light shielding layer 11, so that the precursor flows smoothly without staying on one light receiving element 2. In addition, the uniformity of the film thickness is improved.
[0036]
The second light shielding layer 12 is provided on the interlayer insulating film 13 so as to cover the gap GP between the first light shielding layers 11.
[0037]
The light shielding portion 12a of the second light shielding layer 12 prevents light from entering between the light receiving elements.
[0038]
Then, on the second light-shielding layer 12, a protective film 18 for preventing intrusion of moisture, alkali ions and the like is provided. This protective film is preferably formed of silicon nitride or the like deposited by a plasma CVD method.
[0039]
As described above, the light-shielding means is constituted by the plurality of light-shielding layers 11 and 12 having different patterns from each other, and a gap is formed between adjacent light-receiving elements 2 in the first light-shielding layer 12 below the coating insulating film. In addition, the thickness of the insulating film is made uniform. The light-shielding means shields at least a main part of the peripheral circuit 21 from light.
[0040]
Next, an example of a peripheral circuit for one pixel used in the photoelectric conversion element of the present invention will be described with reference to FIG.
[0041]
The anode of the photodiode forming the photoelectric conversion unit 2 is connected to the reset means 51 and the gate of the pMOS transistor 53 of the source follower amplifier forming the amplification unit 52.
[0042]
The pMOS transistor 53 'serving as a load of the cathode and the source follower amplifier of the photodiode is connected to a high-potential reference voltage source.
[0043]
The amplified optical signal is transferred by turning on the transfer nMOS transistor 54 and is temporarily stored in the storage capacitor 55.
[0044]
Since the storage capacitor 55 is connected to the gate of the pMOS transistor 56 of the source follower amplifier, the output of the source follower is amplified depending on the voltage stored in the storage capacitor. The nMOS transistor 54, the storage capacitor 55, the pMOS transistor 56 serving as a source follower amplifier, and the load pMOS transistor 56 'constitute signal holding means.
[0045]
The output of the signal holding means is connected to the noise signal removing means.
[0046]
The noise signal removing means is composed of a pair of sampling circuits, one of which is composed of a noise transfer nMOS transistor 57, a noise holding capacitor 59, a reset nMOS transistor 61, and a scanning transistor 64 '.
[0047]
The other is composed of an nMOS transistor 58 for transferring an optical signal, an optical signal holding capacitor 60, an nMOS transistor 62 for reset, and a scanning transistor 64.
[0048]
FIG. 6 is a timing chart for explaining the operation of the circuit of FIG. In response to the input of the start pulse SP, first, a high-level pulse is input to the terminal φCR of the gate of the reset nMOS transistors 61 and 62, and the noise holding capacitor 59 and the optical signal holding capacitor 60 become the low potential (ground level) reference voltage. Reset.
[0049]
When a high-level pulse is input to the terminal φTN, the noise transfer nMOS transistor 57 is turned on, and an output voltage amplified according to the voltage accumulated in the capacitor 55 is read out to the noise holding capacitor 59. This output voltage is a noise voltage immediately after the photoelectric conversion unit 2 is reset in the previous field.
[0050]
Then, a high-level pulse is input to the terminal φT1, the transfer nMOS transistor 54 is turned on, and the output voltage of the amplifier is read out to the storage capacitor 55. This output voltage is the optical signal voltage of the current field.
[0051]
Subsequently, when a high-level pulse is input to the terminal φTS, the nMOS transistor 58 for optical signal transfer is turned on, and the optical signal is read out and held by the capacitor 60.
[0052]
Next, a high-level pulse is input to the terminal φR to turn on the reset nMOS transistor RT, connect the anode of the photodiode to the reset reference voltage source _VSR , and reset to the reset potential (period tr ). Subsequently, a high-level pulse is input to the terminal φTI to turn on the nMOS transistor 54, and the voltage component immediately after the reset of the photodiode is read out to the capacitor 55 as a noise voltage (period tn1).
[0053]
While the photodiode is performing the photocarrier accumulation operation, the voltages held in the noise holding capacitor 59 and the optical signal holding capacitor 60 are applied to the common output signal lines 65 and 66 via the scanning transistors 64 and 64 ', respectively. Is output to
[0054]
A difference circuit 67 is connected to the common output signal lines 65 and 66, and performs a process of subtracting a noise voltage from an optical signal voltage.
[0055]
The noise voltage held in the storage capacitor 55 is transferred to the capacitor 59 when a high-level pulse is input to the terminal φTN again (period tn2). Then, a high-level pulse is input to the terminal φT1 again, the optical signal is held in the storage capacitor (period ts1), and the optical signal is transferred to the capacitor 60 by inputting the high-level pulse to the terminal φTS ( Period ts2). Then, in the next accumulation period, the noise and the optical signal accumulated in the capacitors 59 and 60 are sequentially scanned for each pixel, and the difference processing is performed.
[0056]
FIG. 7 is a diagram showing an example of the layout of the photoelectric conversion elements on the semiconductor chip. The high potential VDD voltage line 21 and the reset are arranged on one side (upper side in the figure) along the arrangement of the light receiving elements 2. reset line 22 of the potential VSR, reference voltage lines are arranged based on the reference voltage line array unit 24 supplies a reference voltage such as the ground line 23 of the ground potential.
[0057]
On the other side (lower side in the figure) of the light receiving element array, reset means, amplifying section, signal holding means, and noise signal removing means as peripheral circuits are arranged in each of the arrangement sections 25, 26, 27. The constituent transistors are substantially shielded from light mainly by the second light-shielding layer.
[0058]
FIG. 8 is a diagram showing the upper surface of another photoelectric conversion element of the present invention, and shows a pattern of the light shielding means. FIG. 9 shows each pattern of the first and second light shielding layers corresponding to FIG.
[0059]
74 and 75 are first light-shielding layers, and here, 74 and 75 also serve as wiring. 74 and 75 are, for example, ground lines and reset lines.
[0060]
Second light-shielding layers 70, 71, 72, and 73 are disposed above the first light-shielding layers 74 and 75 with a coating-type insulating film interposed therebetween to shield peripheral circuits from light.
[0061]
As described above, the first light shielding layers 74 and 75 are vertically separated from each other by an interval of one third or more of the vertical side of the opening.
[0062]
Therefore, they are connected to the light-shielding portions 71 and 72 of the second light-shielding layer located at positions covering the gaps, respectively, via the contact holes CN provided in the coating type insulating film.
[0063]
In this manner, the ground voltage, the high-potential voltage through the layer 70, and the reset voltage through the light-shielding portion 71 are supplied to the peripheral circuits at the bottom in the drawing from above in the drawing.
[0064]
Between the first light-shielding layers 74 and 75, a light-shielding portion 73 of the second light-shielding layer is arranged so as to fill the gap and obtain electrical connection. Nevertheless, a gap through which light passes remains between the light receiving elements, but there is no problem since the area under the light receiving element is an element isolation region.
[0065]
FIG. 9 shows a pattern of the first light shielding layer 11 and the second light shielding layer 12 in FIG.
[0066]
FIG. 10 shows an example of a contact type image sensor using the photoelectric conversion element of the present invention. A plurality of photoelectric conversion elements 31 in which a plurality of light receiving elements are arranged one-dimensionally are arranged on a ceramic substrate or a glass epoxy substrate 32 in the form of one line or stagger, and are electrically connected to wiring on the substrate 32 by wire bonding. Then, for protection, the upper part of the photoelectric conversion device is covered with a chip coating agent 33 made of a silicone resin or the like. This substrate 32, a lens array 34 for condensing the reflected light from the document and forming an image on the light receiving element surface, an LED light source 35 for generating red, green, and blue light, and a document support 36 made of a transparent member Are assembled to form a contact image sensor.
[0067]
When the LED light source 35 emits only red light, the photoelectric conversion element 31 is driven to read red information. Next, the red and blue LEDs are turned off, and the green LED is turned on to read green information. Finally, only the blue LED is turned on to read blue information. Thus, a color image of a color original can be read without using a color filter.
[0068]
FIG. 11 is a graph showing the relationship between the ratio of the length of the gap GP of the first light-shielding layer to the length of the side of the opening in the photoelectric conversion element for a contact image sensor, and the bright output variation failure rate. It is a thing. The defect rate decreases until the ratio of the gap becomes approximately 1/3, and after that, there is almost no change in the defect rate.
[0069]
As described above, by adopting this configuration, the variation in the thickness of the interlayer insulating film was reduced, the shift in the spectral sensitivity was suppressed, and the variation in the sensitivity was reduced.
[0070]
12 and 13 show a top view and a cross section of a photoelectric conversion element according to still another embodiment of the present invention.
[0071]
The difference from the element shown in FIG. 8 is that one electrode / wiring 76 of the photodiode extends into the opening.
[0072]
In the surface layer of the semiconductor substrate 19, one semiconductor region 77 serving as one anode or cathode of the photodiode is provided in one opening in an island shape, and the first light-shielding layer is provided through the contact hole of the insulating film 16. The electrodes 74 and 75 are connected to an electrode wiring 76 composed of the same film.
[0073]
Reference numeral 2 denotes a photoelectric conversion unit (light receiving element) that generates carriers by receiving light and serves as a depletion layer.
[0074]
An element isolation region 15 is provided between each light receiving element.
[0075]
Further, first light-shielding layers 74 and 75 and second light-shielding layers 70, 71 and 72 for shielding light between the light receiving elements are provided on the element isolation region 15.
[0076]
If necessary, the second light-shielding layer 70 and the electrode wiring 76 may be provided with a cutout 79 in the second light-shielding layer 70 as shown in FIG. 12 in order to reduce the capacitance between them. Good.
[0077]
Also in this example, the light-blocking means between the light receiving elements is a reference voltage line, and the parasitic resistance of the reference voltage line is reduced to suppress the variation between pixels.
[0078]
FIG. 14 is a circuit diagram of one pixel of the photoelectric conversion element of the present invention.
[0079]
The main points different from those shown in FIG. 5 are that a MOS transistor 81 for charge transfer is provided between the photodiode and the gate of the MOS transistor 53, that the signal holding means of FIG. The line reset is performed by a pair of MOS transistors 61 at the same time, and the conductivity types of some MOS transistors are reversed.
[0080]
FIG. 15 shows an operation timing chart thereof.
[0081]
First, immediately after the reset by the nMOS transistor RT, the nMOS transistor 57 is turned on to store a reset noise component in the capacitor 59.
[0082]
The optical signal charges stored in the photodiode are transferred and stored in the gate of the nMOS transistor 53 by turning on the MOS transistor 81. By turning on the nMOS transistor 58, the optical signal amplified from the nMOS transistor is stored in the capacitor 60. The pair of nMOS transistors 64 ′ and 64 are turned on by a horizontal shift register (not shown), and the difference between the reset noise component and the optical signal component is output from the differential amplifier 87. Thus, an optical signal from which the reset noise component for one pixel has been removed is obtained. Next, a transistor 64 (N + 1) (not shown) is turned on to obtain an optical signal from an adjacent pixel.
[0083]
In the example of FIGS. 12 to 14, the ground voltage in each pixel (reset voltage) is supplied via the light shielding portion 72 and 75, criteria voltage of the high potential may be supplied via a 70 or 74 .
[0084]
A method for manufacturing the photoelectric conversion element shown in FIGS. 8 and 12 will be briefly described.
[0085]
A Si wafer is prepared, and a thick insulating film (element isolation region) 15 made of silicon oxide is formed by selective oxidation. A gate electrode of each MOS transistor is formed, and a source / drain and a semiconductor region 77 are formed. An insulating film 16 is formed by CVD or the like, and a contact hole is opened. A conductive film such as Al to be the first light-shielding layers 74 and 75 and the electrodes and wirings 76 is formed, and the light-shielding patterns and the wiring patterns are etched.
[0086]
An SOG precursor is spin-coated and heat-treated to form an interlayer insulating film 13 of a coating type insulating film. A through hole is formed in the insulating film 13, a conductive film such as Al to be the second light shielding layers 70, 71 and 72 is formed, and the light shielding pattern and the wiring pattern are etched. The protection film 18 is formed by CVD or the like.
[0087]
As described above, the insulating film precursor applied on the first light-shielding layers 74, 75, and 76 flows through the space between the first light-shielding layers. Therefore, by adopting this configuration, the variation in the thickness of the interlayer insulating film is reduced, the shift in the spectral sensitivity can be suppressed, and the variation in the sensitivity is reduced.
[0088]
The structure is changed so that the MOS transistor 81 is changed to a charge transfer MOS gate, all the carriers accumulated in the semiconductor region 77 are transferred to the diffusion layer connected to the gate of the transistor 53, and the semiconductor region 77 is completely depleted. Is also preferred.
[0089]
【The invention's effect】
According to the present invention, since the precursor of the coating type insulating film flows through the gap provided in the first light shielding layer, the difference in the thickness of the insulating film between at least adjacent light receiving elements in one chip is suppressed.
[0090]
Further, since the second light shielding layer is provided so as to cover the gap, it is possible to shield between the light receiving elements and suppress generation of unnecessary photogenerated carriers.
[0091]
Thus, an insulating film having a uniform thickness can be formed at a relatively low cost, and a photoelectric conversion element with small sensitivity variation can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining a structure of a photoelectric conversion element of the present invention.
FIG. 2 is a top view of the photoelectric conversion element of the present invention.
FIG. 3 is a sectional view of the photoelectric conversion element taken along line CC ′ in FIG. 2;
FIG. 4 is a sectional view of the photoelectric conversion element taken along line DD ′ in FIG. 2;
FIG. 5 is a circuit diagram of a part of the photoelectric conversion element of the present invention.
FIG. 6 is a diagram showing an operation timing chart of the photoelectric conversion element of the present invention.
FIG. 7 is a diagram showing a layout of a circuit block of the photoelectric conversion element of the present invention.
FIG. 8 is a top view of the photoelectric conversion element of the present invention.
FIG. 9 is a top view of the light shielding means used in the photoelectric conversion element of the present invention.
FIG. 10 is a sectional view of an image sensor according to the present invention.
FIG. 11 is a diagram showing the relationship between the length of the gap with respect to the length of the side of the opening of the light-shielding layer and the variation defect rate of the bright output.
FIG. 12 is a top view of another photoelectric conversion element according to the present invention.
FIG. 13 is a sectional view taken along the line EE ′ of FIG. 12;
FIG. 14 is a circuit diagram of another photoelectric conversion element according to the present invention.
FIG. 15 is a diagram showing an operation timing chart of the photoelectric conversion element according to the present invention.
FIG. 16 is a cross-sectional view of a conventional photoelectric conversion element.
FIG. 17 is a top view of a photoelectric conversion element.
[Explanation of symbols]
1 substrate 2 photoelectric conversion unit (light receiving element)
11 first light shielding layer 12 second light shielding layer 13 interlayer insulating film OP opening GP gap

Claims (15)

A plurality of photoelectric conversion units, and a light blocking unit having an opening disposed on the photoelectric conversion unit, a photoelectric conversion element comprising:
The light-shielding means has a first light-shielding layer, and a second light-shielding layer provided on the first light-shielding layer via an interlayer insulating film,
The first light-blocking layer has a gap for communicating two adjacent openings,
A photoelectric conversion element, wherein a light-shielding portion of the second light-shielding layer is arranged on the gap of the first light-shielding layer. The photoelectric conversion element according to claim 1, wherein the interlayer insulating film is a laminate of an insulating film deposited by a CVD method and a coating type insulating film. 2. The photoelectric conversion element according to claim 1, wherein the length (L1) of the side of the gap is equal to or more than ３ of the length (L2) of the side of the opening. 2. The photoelectric conversion device according to claim 1, wherein said interlayer insulating film is a silicon oxide film. The photoelectric conversion element according to claim 1, wherein a protective film made of a material different from that of the interlayer insulating film is provided on the second light-shielding layer. The photoelectric conversion device according to claim 5, wherein the protective film is a silicon nitride film. The photoelectric conversion element according to claim 1, wherein the light shielding unit has a light shielding unit provided on at least a part of a peripheral circuit for processing a signal from the photoelectric conversion unit. 8. The photoelectric conversion device according to claim 7 , wherein said peripheral circuit is a CMOS circuit. The photoelectric conversion element according to claim 1, wherein an element isolation region is provided between two adjacent photoelectric conversion units. The photoelectric conversion element according to claim 9, wherein the element isolation region includes a region made of silicon oxide. A plurality of photoelectric conversion units, and a light blocking unit having an opening disposed on the photoelectric conversion unit, a photoelectric conversion element comprising:
A light-blocking conductive layer for wiring, and a conductive light-blocking layer provided on the conductive layer via an interlayer insulating film,
The conductive layer has a gap for communicating two adjacent openings,
A photoelectric conversion element, wherein a light-shielding portion of the conductive light-shielding layer is disposed on the gap between the conductive layers, and is connected to the conductive layer. 12. A transistor forming a peripheral circuit is arranged on one side of the one-dimensionally arranged photoelectric conversion units in the arrangement direction, and a reference voltage line is arranged on the other side. Photoelectric conversion element. The photoelectric conversion element according to claim 11, wherein a plurality of wiring patterns are arranged between the adjacent photoelectric conversion units. The photoelectric conversion element according to claim 11, wherein a light-shielding portion of the conductive light-shielding layer between the adjacent photoelectric conversion portions is a part of a wiring. An image sensor comprising: the photoelectric conversion element according to claim 1; and a light source for illuminating a document to be read by the photoelectric conversion element.

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