JP2004363493A - Solid state image sensor and its fabricating process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid state image sensor in which sensitivity can be enhanced by suppressing unevenness in sensitivity and color thereby enhancing transmissivity above a light receiving section and generation of a dark current due to hydrogen annealing can be suppressed during fabrication, and to provide its fabrication process. <P>SOLUTION: Transfer electrodes 4 and 5 at a charge transfer section 3 are constituted of the same electrode layer, the transfer electrodes 4 and 5 are formed on a substrate through an insulating film including an oxide film and an overlying nitride film, and a part 7 from where the nitride film is removed is provided between light receiving sections 2 in the direction parallel with the charge transfer section 3 thus constituting a solid state image sensor 1. The solid state image sensor 1 is fabricated through a step for forming an oxide film and a nitride film sequentially on a substrate, a step for forming an opening 7 by removing the nitride film at a part between the light receiving sections 2, a step for forming an oxide film to fill the opening 7, and a step for forming transfer electrodes 4 and 5 by the same electrode layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a solid-state imaging device having a charge transfer unit and a method for manufacturing the solid-state imaging device.
[0002]
[Prior art]
2. Description of the Related Art In a CCD solid-state imaging device, a MONOS (metal oxide nitride oxide semiconductor) structure is employed for the purpose of efficiently transferring data at a low voltage.
By employing this MONOS structure, the thickness of the gate insulating film below the transfer electrode in a vertical transfer register or the like can be made substantially constant, and the lower surface of the transfer electrode can be made flat. This makes it possible to transfer charges efficiently at a low voltage.
[0003]
In the CCD solid-state imaging device having the MONOS structure, it is necessary to lay out a region without a nitride film (silicon nitride film) in order to effectively perform hydrogen annealing on the silicon / SiO ₂ interface. By performing the hydrogen annealing, the interface state at the silicon / SiO ₂ interface can be reduced, and the generation of dark current can be suppressed.
[0004]
As a method of forming a region without a nitride, for example, a configuration in which a nitride film on a light receiving unit is cut in a CCD solid-state imaging device of an IT (interline transfer) system or a FIT (frame interline transfer) system is employed. ing.
[0005]
Further, for example, a configuration in which a nitride film on a channel stop is cut in an accumulation region of a CCD solid-state imaging device of an FT (frame transfer) system or an FIT system is adopted (for example, see Patent Document 1).
[0006]
[Patent Document 1]
Japanese Patent Publication No. 5-16178
[Problems to be solved by the invention]
By the way, in a CCD solid-state imaging device, formation of a nitride film on a light receiving portion has been considered for the purpose of increasing the sensitivity. This is because, by forming a nitride film, the difference in the refractive index between silicon and the light-receiving portion is smaller than that in the case of an oxide film, so that the reflectance at the interface can be reduced.
[0008]
In this case, a nitride film (second layer) is formed on the light receiving portion separately from the nitride film (first layer) having the MONOS structure, but the entire light receiving portion is covered with the nitride film. Then, it becomes difficult for hydrogen to pass through and the effect of hydrogen annealing cannot be obtained, so that a nitride film is formed on a part of the light receiving portion.
[0009]
Alternatively, the same effect can be obtained by leaving a part of the nitride film of the insulating film having the MONOS structure instead of removing the entire nitride film at the opening on the light receiving portion.
[0010]
However, as the size of the pixels in the CCD solid-state imaging device decreases, it is necessary to leave the nitride film in a part of the opening on the light receiving part and etch off the nitride film in the other part of the area. It becomes difficult from.
[0011]
FIG. 10 shows a case where this problem is applied to a CCD solid-state imaging device employing a single-layer transfer electrode as an example.
In this case, as shown in FIG. 10A, a nitride film 54 having a low reflection effect is formed over the transfer electrodes 51 and 52 and the light receiving portion 53, and the nitride film 54 is formed on the light receiving portion 52. Is patterned into a stripe pattern so as to partially remain. The transfer electrode 51 and the transfer electrode 52 are both formed of the same (single-layer) electrode layer (polycrystalline silicon layer or the like).
[0012]
However, in practice, even when the single-layer transfer electrodes 51 and 52 are employed as shown in FIG. 10A as well as the multi-layer transfer electrodes, the height is large on the transfer electrodes 51 and 52 and the light receiving section 53. Due to the difference, there are large irregularities under the nitride film 54.
When the pixel size (cell size) is reduced to about 2 μm, the width of the opening of the light receiving unit 53 may be 1 μm or less. At this time, even if it is attempted to process the nitride film 54 in a portion where large irregularities exist due to the transfer electrodes 51 and 52 into the pattern of FIG. 10A, generally, as shown in FIG. The pattern shape tends to collapse.
In the opening on the light receiving portion 53, the transmittance of the portion where the nitride film 54 is present is high, and the transmittance of the portion without the nitride film 54 is low. The transmittance differs for each pixel, and sensitivity unevenness and color unevenness are likely to occur. Also, so-called shading is likely to occur in peripheral pixels.
[0013]
On the other hand, when only a part of the nitride film of the insulating film having the MONOS structure is left at the opening on the light receiving portion, there is almost no unevenness under the nitride film.
However, also in this case, the processing width of the nitride film becomes narrower as the pixel size is reduced, so that there is a problem that the processing of patterning the nitride film becomes difficult.
[0014]
Therefore, in order to achieve low reflection, it is necessary to form a nitride film over as large an area as possible on the light receiving portion and to ensure that the nitride film has a sufficiently wide window for hydrogen annealing. Required.
[0015]
In order to solve the above-mentioned problem, in the present invention, it is possible to suppress the occurrence of sensitivity unevenness and color unevenness, to improve the sensitivity by increasing the transmittance on the light receiving unit, and to improve the hydrogen annealing during manufacturing. And a method for manufacturing the solid-state imaging device capable of suppressing generation of dark current.
[0016]
[Means for Solving the Problems]
In the solid-state imaging device of the present invention, a charge transfer unit is provided on at least one side of one row of the light-receiving units arranged in a line or a matrix, and the transfer electrodes of the charge transfer unit are configured by the same electrode layer, An insulating film between the substrate and the transfer electrode includes an oxide film on the substrate and a nitride film thereon, and a portion where the nitride film is removed is provided between the light receiving units in a direction parallel to the charge transfer unit. Is what it is.
[0017]
The method for manufacturing a solid-state imaging device according to the present invention is a method for manufacturing a solid-state imaging device in which a charge transfer unit is provided on at least one side of one row of light-receiving units arranged in a line or a matrix. A step of forming an oxide film and a nitride film sequentially thereon, a step of forming an opening by removing the nitride film in a portion between light receiving portions in a direction parallel to the charge transfer portion, and a step of removing the nitride film. Forming an oxide film by filling the opening thus formed, and then forming a transfer electrode of the charge transfer section using the same electrode layer.
[0018]
According to the above-described configuration of the solid-state imaging device of the present invention, since the transfer electrodes of the charge transfer section are formed of the same electrode layer, the transfer electrodes are formed in a single layer, and the adjacent transfer electrodes overlap vertically. Not. Thereby, a step due to the transfer electrode can be reduced, and a gap such as an oxide film is provided between adjacent transfer electrodes between the light receiving units in a direction parallel to the charge transfer unit.
In addition, since a portion where the nitride film is removed is provided between the light receiving portions in a direction parallel to the charge transfer portion, a gap between the portion where the nitride film is removed and the plurality of transfer electrodes is provided. Through this, it becomes possible to supply hydrogen to the interface between the substrate and the oxide film thereon during the production. This eliminates the need to remove the nitride film on the light receiving section, so that the nitride film can be left on the light receiving section, and the reflectance of the incident light is reduced because the refractive index between the nitride film and the substrate is small. It becomes possible.
[0019]
According to the above-described method for manufacturing a solid-state imaging device of the present invention, an opening is formed by removing the nitride film in a portion between the light receiving units in a direction parallel to the charge transfer unit, and the opening from which the nitride film has been removed is formed. By filling the inside and forming an oxide film, hydrogen can be supplied to the interface between the substrate and the oxide film thereover through the oxide film in the opening.
Further, by forming the transfer electrodes of the charge transfer portion with the same electrode layer, a single-layer transfer electrode in which adjacent transfer electrodes do not overlap vertically can be formed. Thus, a step due to the transfer electrode can be reduced, and a gap such as an oxide film can be formed between adjacent transfer electrodes between the light receiving units in a direction parallel to the charge transfer unit. In this manner, the gap is formed between the adjacent transfer electrodes, so that the supply of hydrogen does not hinder the supply of hydrogen through the gap between the adjacent transfer electrodes during the supply of hydrogen.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
According to the present invention, a charge transfer section is provided on at least one side of at least one column of light-receiving sections arranged in a line or a matrix, and a transfer electrode of the charge transfer section is formed of the same electrode layer, and a substrate and a transfer electrode are provided. The solid-state imaging device includes an oxide film on a substrate and a nitride film on the substrate, and a portion where the nitride film is removed between light receiving units in a direction parallel to the charge transfer unit. Element.
[0021]
According to the present invention, in the solid-state imaging device, a second nitride film is provided to cover the entire surface of each light receiving unit.
[0022]
The present invention is to manufacture a solid-state imaging device in which a charge transfer unit is provided on at least one side of one row of light receiving units arranged in a line or a matrix, and an oxide film and a nitride film are formed on a substrate. A step of sequentially forming a film, a step of forming an opening by removing a nitride film in a portion between light receiving sections in a direction parallel to the charge transfer section, and filling the inside of the opening from which the nitride film has been removed. This is a method for manufacturing a solid-state imaging device including a step of forming an oxide film and a step of subsequently forming a transfer electrode of a charge transfer section using the same electrode layer.
[0023]
According to the present invention, in the method for manufacturing a solid-state imaging device, a second nitride film is formed to cover the entire surface of the light receiving unit after the step of forming the transfer electrode of the charge transfer unit.
[0024]
FIG. 1 shows a schematic configuration diagram (plan view) of an embodiment of the solid-state imaging device of the present invention. FIG. 2 is a sectional view taken along line AA of FIG.
This embodiment shows a case where the present invention is applied to a CCD solid-state imaging device.
[0025]
In the solid-state imaging device 1, light receiving units 2 are arranged in a matrix, and a vertical transfer register 3 extending in a vertical direction (vertical direction in the drawing) V is provided on one side of each column of the light receiving units 2 as a charge transfer unit. Have been. A horizontal transfer register (not shown) is connected to one end of the vertical transfer register 3.
Each of the light receiving units 2 constitutes a pixel, and includes a photoelectric conversion unit (not shown) for converting light into electric charge and a charge accumulating unit for accumulating the converted electric charge.
[0026]
The vertical transfer register 3 includes transfer electrodes 4 and 5, and a transfer channel 9 (see FIG. 3) formed on a semiconductor substrate (silicon substrate or silicon epitaxial layer) 11 therethrough for transferring signal charges. It is a charge transfer unit having a CCD structure.
[0027]
A silicon oxide film 12, a nitride film (silicon nitride film) 13, and a silicon oxide film 14 are formed as insulating films between the transfer electrodes 4 and 5 and the silicon substrate 11 thereunder.
That is, the transfer electrodes 4 and 5, the silicon oxide film 14, the nitride film 13, the silicon oxide film 12, and the silicon substrate 11 constitute the above-mentioned MONOS structure.
Since the vertical transfer register 3 has this MONOS structure, as described above, the thickness of the gate insulating film under the transfer electrodes 4 and 5 is made substantially constant, and the lower surfaces of the transfer electrodes 4 and 5 are made flat. Can be formed. Thereby, charge transfer can be efficiently performed at a low voltage.
[0028]
Further, a light-shielding film 8 is formed on the entire device so as to cover the transfer electrodes 4 and 5.
The light shielding film 8 has an opening 9A on the light receiving unit 2 so that light enters the light receiving unit 2.
[0029]
In the solid-state imaging device 1 of the present embodiment, in particular, the transfer electrodes 4 and 5 of each vertical transfer register 3 are constituted by the same electrode layer (first layer).
The transfer electrodes 4 and 5 are made of, for example, a polycrystalline silicon film, and can be formed by, for example, forming a non-doped polycrystalline silicon film and then doping impurities.
These transfer electrodes 4 and 5 are insulated from each other by a silicon oxide film 15 covering the electrode surface.
[0030]
Each of the transfer electrodes 4 and 5 has a conductor portion extending in the horizontal direction (horizontal direction in the drawing) H and an electrode portion protruding along the vertical transfer register. The conductor portion is arranged and formed at a portion between pixels in the vertical direction V.
The transfer electrode 4 is arranged on the upper side in the drawing with respect to the light receiving section 2, and the electrode section protrudes downward.
The transfer electrode 5 is disposed on the lower side in the figure with respect to the light receiving unit 2, and the electrode unit protrudes upward.
The transfer electrodes 4 and 5 vertically adjacent to each other in the drawing are arranged such that the respective conductor portions and the respective electrode portions face each other with a narrow gap formed by the insulating film therebetween.
The transfer channel 9 is formed below the electrode portions of the transfer electrodes 4 and 5.
[0031]
Further, in the solid-state imaging device 1 of the present embodiment, a nitride film (silicon nitride film) 6 is formed on the light receiving section 2 so as to cover the opening formed by the transfer electrodes 4 and 5.
The nitride film 6 covers the light receiving unit 2, and the end of the film 6 extends over the transfer electrodes 4 and 5.
[0032]
The nitride film has a property of having a higher refractive index and a higher transmittance of blue and green light than a silicon oxide film.
For this reason, by forming the nitride film 6 on the light receiving portion 2, the spectral characteristics and sensitivity of the light receiving portion 2 can be improved by the nitride film 6 and the nitride film 13 having the MONOS structure.
[0033]
Furthermore, in the solid-state imaging device 1 of the present embodiment, a nitride having a MONOS structure is provided below the transfer electrodes 4 and 5 between the light receiving units 2 in the vertical direction V (direction parallel to the vertical transfer register 3). An opening 7 from which the film 13 has been removed is provided. The inside of the opening 7 is filled with a silicon oxide film 14 as shown in FIG.
Through the opening 7 of the nitride film 13, hydrogen can be supplied to the silicon substrate 11 in hydrogen annealing performed during manufacturing.
This is because hydrogen has a property that it is difficult for the nitride film 13 to pass through, while the silicon oxide film 14 has a property that it is relatively easy to pass.
[0034]
If, for example, the nitride film 13 having a MONOS structure or the nitride film 6 on the light receiving portion 2 is formed entirely, hydrogen cannot be supplied to the silicon substrate 11.
On the other hand, since the opening 7 for hydrogen annealing is formed in the nitride film 13 as described above, even if the light receiving section 2 and the transfer channel are covered with the nitride film, 100 nm is passed through the opening 7. Since hydrogen can be supplied to a range of up to 200 μm, it is possible to supply hydrogen to almost the entire surface of the silicon substrate 11.
[0035]
In FIG. 2, reference numeral 16 denotes an interlayer insulating layer made of SiO ₂ or the like, and reference numeral 17 denotes an insulating layer including a passivation film and a flattening film.
When a silicon nitride film formed by plasma CVD is used as the passivation film, hydrogen can be supplied from the passivation film to the interface between the substrate and the silicon oxide film thereon.
A color filter, an on-chip lens, and the like (not shown) are provided above the insulating layer 17 as necessary.
[0036]
According to the configuration of the solid-state imaging device 1 of the present embodiment described above, the opening 7 from which the nitride film 13 having the MONOS structure is removed is provided between the pixels in the vertical direction V (between the light receiving units 2), and the transfer is performed. Since the electrodes 4 and 5 are formed of the same (single-layer) electrode layer, a gap between two adjacent transfer electrodes 4 and 5 is formed on the opening of the nitride film 13 between the light receiving sections 2. is there.
Thus, when the solid-state imaging device 1 is manufactured, the silicon substrate 11 and the silicon oxide film 12 thereon are formed through the gap between the transfer electrodes 4 and 5 and the silicon oxide film 14 in the opening 7 of the nitride film 13. Can be supplied to the interface.
Further, since it is not necessary to cut the nitride film 13 on the light receiving unit 2, the nitride film 13 can be left entirely on the light receiving unit 2.
Since the opening 7 of the nitride film 13 is formed in a portion with little unevenness, it can be formed easily and without pattern collapse.
[0037]
Then, the nitride film 13 is entirely left on the light receiving unit 2 and the second nitride film 6 is provided so as to cover the entire light receiving unit 2, so that the entire surface of the light receiving unit 2 has low reflection. It is possible to configure a film structure.
That is, even if the entire surface of the light receiving unit 2 is formed to have a low reflection film structure, the solid-state imaging device 1 having a configuration in which hydrogen annealing for reducing dark current is effective can be achieved.
[0038]
Further, since the nitride film 6 is formed on the entire surface of the light receiving portion 2 and not over the light receiving portion 2 but over the transfer electrodes 4 and 5, the nitride film 6 is Even if the pattern is distorted due to the unevenness due to 5, it is possible to form the pattern by covering the entire surface of the light receiving unit 2 while keeping the effect of the pattern collapse on the transfer electrodes 4 and 5.
Thereby, the sensitivity can be improved over the entire surface of the light receiving section 2, and there is no problem of color unevenness or color shading due to pattern collapse of the nitride film 6.
Since the transfer electrodes 4 and 5 are formed by the same (single-layer) electrode layer, the transfer electrodes 4 and 5 are compared with the conventional CCD solid-state imaging device in which the transfer electrodes are formed by multilayer electrode layers. , 5 can be reduced, so that the range of light incident on the light receiving unit 2 can be widened and the amount of incident light can be increased. With this, the sensitivity of the light receiving section 2 can be improved.
[0039]
Therefore, according to the present embodiment, it is possible to realize the solid-state imaging device 1 with high sensitivity and less color unevenness and color shading.
[0040]
As the pixels (cells) of the solid-state imaging device become finer, the sensitivity is reduced, and the above-described problems of color unevenness and color shading become apparent.
On the other hand, according to the present embodiment, the processing of the cut-off of the nitride film is facilitated, so that the processing can be easily performed even if the pixel (cell) becomes finer. Further, since the influence of the pattern collapse of the nitride film 6 can be eliminated, the sensitivity can be improved by the nitride films 13 and 6 provided on the entire surface of the light receiving section 2 and color unevenness and color shading can be reduced. Can be prevented from occurring.
Therefore, the pixel (cell) can be miniaturized, the number of pixels can be increased, and the size of the imaging device including the solid-state imaging device can be reduced.
In particular, as the pixel (cell) becomes finer, the advantages of the solid-state imaging device 1 of the present embodiment become larger.
[0041]
The solid-state imaging device 1 of the present embodiment can be manufactured, for example, as follows.
[0042]
First, as shown in a plan view in FIG. 3, a transfer channel 9 and a channel stop region 10 of the vertical transfer register 3 are formed in a silicon substrate 11 by ion implantation or the like.
Before and after the step of forming these regions, a silicon oxide film 12 and a nitride film 13 to be a gate insulating film are sequentially formed as shown in a sectional view of FIG. 4A.
[0043]
Next, as shown in a cross-sectional view in FIG. 4B and a plan view in FIG. 5, the nitride film 13 in the inter-pixel portion is etched off by dry etching or the like to form an opening 7 without the nitride film 13.
Subsequently, as shown in FIG. 6C, the silicon oxide film 12 in the region where the nitride film 13 is cut (the region below the opening 7) is removed by wet etching.
Further, an oxidation process is performed to oxidize the portion where the nitride film 13 and the silicon oxide film 12 have been cut. Thereby, as shown in FIG. 6D, a silicon oxide film 21 is formed inside the opening of the nitride film 13.
[0044]
Next, as shown in FIG. 7E, a silicon oxide film 14 is formed as a charge injection blocking film. For example, it is formed with a thickness of 10 to 20 nm.
The silicon oxide film 14 may be formed by oxidizing the nitride film 13 or may be formed as an HTO film (High Temperature Oxide film) by high-temperature low-pressure CVD.
The silicon oxide film 14 and the silicon oxide film 21 are made of the same silicon oxide, and the boundary is not clear. Therefore, the silicon oxide film 14 and the silicon oxide film 21 are collectively shown in the following drawings.
[0045]
Next, as shown in FIG. 7F, an electrode layer made of polycrystalline silicon, WSi, or the like is formed and patterned to form an electrode layer of the same layer (single layer). The electrodes 4 and 5 are formed.
Subsequently, for example, the surfaces of the transfer electrodes 4 and 5 are thermally oxidized to form a silicon oxide film 15.
[0046]
Note that an impurity region constituting the light receiving section 2 is formed in the silicon substrate 11 before the next step of forming the second nitride film 6.
The impurity region constituting the light receiving unit 2 is formed by ion-implanting an impurity into the silicon substrate 11. This ion implantation step is performed before and after the step of forming the transfer channel 9 and the channel stop region 10, and after the transfer electrodes 4 and 5 are formed for self-alignment with the openings formed by the transfer electrodes 4 and 5. There is.
[0047]
Next, a nitride film is formed on the entire surface covering the surface, and is patterned by etching. As shown in FIG. A nitride film 6 is formed.
[0048]
Next, as shown in FIG. 8H, an interlayer insulating film 16 is formed above the transfer electrodes 4 and 5. As the interlayer insulating film 16, BPSG (boron phosphorus silicate glass) can be used.
[0049]
Next, a metal film that becomes the light-shielding film 8 is entirely formed so as to cover the surface, an opening 8A is formed on the light-receiving unit 2, and the light-shielding film 8 is formed as shown in FIG. 9I.
The light-shielding film 8 may be Cu-based, tungsten-based, or aluminum-based.
[0050]
Thereafter, a passivation film made of a silicon nitride film is formed by a plasma CVD method, for example, a flattening film is formed thereon, and the entire surface is covered with an insulating layer 17 as shown in FIG. 9J.
[0051]
The hydrogen annealing is performed after the step of forming the passivation film made of the silicon nitride film formed by the plasma CVD method and before the step of forming the color filter.
That is, annealing (heat treatment) is performed at a temperature of, for example, about 400 ° C., and silicon is removed from the silicon nitride film through the interlayer insulating film 16, the gap between the transfer electrodes 4 and 5, and the silicon oxide film 14 in the opening of the nitride film 13. Hydrogen is supplied to the interface between the substrate 11 and the silicon oxide film 12.
[0052]
Further, a color filter and an on-chip lens are formed as necessary.
Thus, the solid-state imaging device 1 of the present embodiment can be manufactured.
[0053]
According to the above-described manufacturing process, the nitride film cut-off process (the process of forming the opening 7 in the nitride film 13) is performed before the transfer electrode 4 and 5 forming process. 5, the nitride film can be cut off without any irregularities.
Thereby, the problem of the pattern collapse of the nitride film described above does not occur, and the processing of the cutoff becomes easy. Therefore, even if the pixel (cell) is reduced in size, the nitride film can be easily cutoff. be able to.
[0054]
In the above-described manufacturing method, the silicon oxide film 12 under the opening 7 of the nitride film 13 is once removed by wet etching. However, the present invention is not limited to the case where the silicon oxide film 12 is also removed. It is not done.
[0055]
In the above-described embodiment, the present invention is applied to the CCD solid-state imaging device. However, the present invention can be applied to solid-state imaging devices having other configurations.
For example, the present invention can be similarly applied to a solid-state imaging device having a configuration in which a charge transfer unit other than a CCD structure is provided on one side of a row of light receiving units.
[0056]
The present invention is not limited to the above-described embodiment, and may take various other configurations without departing from the gist of the present invention.
[0057]
【The invention's effect】
According to the present invention described above, during the manufacture of the solid-state imaging device, the substrate and the oxide film on the substrate are passed through the gap between the adjacent transfer electrodes and the portion (opening) from which the nitride film has been removed by hydrogen annealing. Hydrogen can be supplied to the interface, which can reduce dark current.
Further, it is not necessary to remove the nitride film on the light receiving portion, and by leaving the nitride film on the light receiving portion, a low reflection film can be formed, thereby increasing the sensitivity of the light receiving portion. In addition, there is no problem of color unevenness or color shading due to pattern collapse of the nitride film.
Therefore, according to the present invention, it is possible to realize a solid-state imaging device that generates little dark current, has high sensitivity, and has little color unevenness and color shading.
[0058]
Further, according to the present invention, when forming an opening in the nitride film, since there is no step under the nitride film, the processing can be easily performed.
Therefore, the pixels (cells) can be miniaturized, the number of pixels of the solid-state imaging device can be increased, and the size of an imaging device including the solid-state imaging device can be reduced.
In particular, as the pixels (cells) become finer, the advantages of the configuration of the present invention become greater.
[0059]
Further, in the present invention, when the second layer nitride film is formed so as to cover the entire surface of each light receiving section, the nitride film remaining on the light receiving section and the second layer nitride film form: Further, the sensitivity can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram (plan view) of an embodiment of a solid-state imaging device according to the present invention.
FIG. 2 is a sectional view taken along line AA of FIG.
FIG. 3 is a process diagram (plan view) showing a manufacturing process of the solid-state imaging device in FIG. 1;
FIGS. 4A and 4B are process diagrams (cross-sectional views) showing manufacturing processes of the solid-state imaging device of FIG. 1;
FIG. 5 is a process diagram (plan view) showing a manufacturing process of the solid-state imaging device of FIG. 1;
6A and 6B are process diagrams (cross-sectional views) showing manufacturing processes of the solid-state imaging device in FIG. 1;
FIGS. 7E and 7F are process diagrams (cross-sectional views) showing manufacturing processes of the solid-state imaging device of FIG.
FIG. 8 is a process diagram (cross-sectional view) showing a manufacturing process of the solid-state imaging device of FIG. 1;
9 is a process diagram (cross-sectional view) showing a manufacturing process of the solid-state imaging device of FIG. 1; FIG.
FIGS. 10A and 10B are diagrams for explaining a problem when a pattern of a nitride film is formed on a part of a light receiving portion.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 solid-state imaging device, 2 light receiving section, 3 vertical transfer register, 4, 5 transfer electrode, 6, 13 nitride film (silicon nitride film), 7 aperture, 8 light shielding film, 10 transfer channel

Claims (4)

A charge transfer unit is provided on at least one side of at least one row of the light receiving units arranged in a line or a matrix,
The transfer electrode of the charge transfer unit is configured by the same electrode layer,
An insulating film between the substrate and the transfer electrode includes an oxide film on the substrate and a nitride film thereon,
A solid-state imaging device, wherein a portion from which the nitride film is removed is provided between the light receiving portions in a direction parallel to the charge transfer portion. 2. The solid-state imaging device according to claim 1, wherein a second layer of a nitride film is provided so as to cover an entire surface on each of the light receiving units. 3. A method for manufacturing a solid-state imaging device in which a charge transfer unit is provided on at least one side of at least one row of light-receiving units arranged in a line or a matrix,
A step of sequentially forming an oxide film and a nitride film on a substrate;
Forming a hole by removing the nitride film in a portion between the light receiving portions in a direction parallel to the charge transfer portion;
Forming an oxide film by filling the opening from which the nitride film has been removed;
Forming a transfer electrode of the charge transfer section using the same electrode layer. 4. The method according to claim 3, wherein after the step of forming the transfer electrode of the charge transfer section, a second nitride film is formed so as to cover the entire surface of the light receiving section.

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