JP2002368206A - Solid-state imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid-state imaging device which can prevent adjacent pixels from having color mixture without deteriorating the smear characteristic. SOLUTION: This solid-state imaging device has a plurality of photodetection parts 5 and a channel stopper CS for preventing electric charges from flowing out among the photodetection parts 5, and also has a plurality of color filters with mutually different spectral characteristics above the photodetection parts 5. At least a portion MCS of the channel stopper CS, formed around a photodetection part which receives light from a yellow filter having the highest spectral sensitivity among the color filters, is formed with a higher potential barrier against signal charges than channel stoppers CS of other regions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a solid-state imaging device in which color filters having different spectral characteristics are arranged above a light receiving section.

[0002]

2. Description of the Related Art In a CCD solid-state imaging device, signals corresponding to three primary colors of RGB are obtained by using optical means to obtain color information. 2. Description of the Related Art Methods of obtaining color information have been roughly divided into a single-chip type in which color information can be obtained by one of the CCD solid-state imaging devices and a three-plate type in which color information can be obtained by three of the CCD solid-state imaging devices. . In the single-panel type, color filters of primary colors red (R), green (G), and blue (B) are provided for each pixel mainly on the surface of the solid-state imaging device.
Alternatively, there is a type in which complementary color filters such as complementary colors yellow (Ye), cyan (Ce), and magenta (Mg) are provided to simultaneously obtain color information.

FIG. 9 is a plan view of a main part of a pixel portion of a CCD solid-state imaging device using the above-described single-plate type color filter. FIG. 10A shows AA ′ in the horizontal direction of FIG.
It is sectional drawing along the line. FIG. 11A is a cross-sectional view taken along line BB ′ in the vertical direction of FIG.

In a p-type silicon substrate or a p-type well (hereinafter, referred to as a substrate) 10 formed in the silicon substrate, for example, an n-type impurity region 11 or the like is formed.
The photoelectric conversion is performed in a region centered on the pn junction between the light-receiving portion and the light-receiving portion 5 for generating signal charges and accumulating the signal charges for a certain period of time. In addition, a high-concentration p-type impurity region 1 is formed on the surface of n-type impurity region 11.
2 is formed, whereby the photodiode is formed not on the surface but on the bulk side, thereby forming a buried photodiode.

The substrate 10 is made of, for example, an n-type impurity region and has a transfer channel CH for transferring signal charges.
Are formed parallel to the light receiving units 5 arranged in the vertical direction. The transfer channel CH is formed at a predetermined distance from the light receiving units 5 on both sides.

[0006] Between the light receiving section 5 and the transfer channel CH, a read gate section 6 made of, for example, a p-type impurity region is formed. The read gate unit 6 is formed separately for each cell in the same column, and forms a variable potential region between the light receiving unit 5 and one transfer channel CH.

A channel stopper CS made of a high-concentration p-type impurity region is formed along the other three sides of the light receiving section 5 except for the area where the readout gate section 6 is formed. The channel stopper CS prevents signal charges generated in the light receiving unit 5 from flowing out to different pixels.

A first vertical transfer electrode TE1 made of first-layer polysilicon is interposed between the light receiving sections 5 so as to be orthogonal to the transfer channel CH via an insulating film 20 such as a silicon oxide film.
Is formed by stretching. First vertical transfer electrode TE1
Has a rectangular shape slightly extending in the transfer channel direction at a portion overlapping with the transfer channel CH and the read gate unit 6.

A second vertical transfer electrode TE2 made of second-layer polysilicon is formed extending between the light receiving sections 5 orthogonally to the transfer channel CH. The second vertical transfer electrode TE2 has a rectangular shape greatly extending on the transfer channel on the opposite side of the lower layer of the first vertical transfer electrode TE1 at a portion overlapping the transfer channel CH and the read gate unit 6.

As shown in FIG. 9, a second vertical transfer electrode TE2 is formed between the first vertical transfer electrodes TE1 with an insulating film 21 interposed therebetween in the formation direction of the transfer channel CH. The end of the transfer electrode TE2 overlaps the first vertical transfer electrode TE1.

The insulating film 2 is formed on the second vertical transfer electrode TE2.
The light-shielding film 30 made of a metal such as aluminum or tungsten is formed in a state where the metal film 1 is interposed. The light-shielding film 30 is open above the light receiving unit 5.

Although not shown, for example, an interlayer insulating film is formed on the entire surface covering the light-shielding film 30, and an on-chip color filter (OCCF) is formed on the interlayer insulating film.
Is arranged. The on-chip color filter is formed of, for example, a color filter of a complementary color system, and is colored, for example, any one of cyan (Cy), magenta (Mg), yellow (Ye), and green (G).
Further, although not shown, an on-chip lens (OCL) made of a light-transmitting material such as a negative photosensitive resin is arranged on the on-chip color filter.

In the solid-state imaging device described above, the first vertical transfer electrode TE1 and the second vertical transfer electrode TE2 have
During charge transfer, for example, four-phase clock signals φV1, φ
V2, φV3, φV4 are applied. When the four-phase clock signal is applied to the first and second vertical transfer electrodes TE1 and TE2, the potential の of the transfer channel CH sequentially changes, and as a result, the charges in the transfer channel CH are transferred in the vertical direction. .

The second vertical transfer electrode TE2 functions not only as a transfer electrode for vertical transfer but also as a control electrode of the read gate unit 6. That is,
When a read voltage is applied to the second vertical transfer electrode TE2 which also serves as a control for the read gate unit 6, the potential of the read gate unit 6 with respect to electrons decreases, and charges are transferred to the transfer channel CH adjacent to the light receiving unit 5. You.

In the above-described solid-state image pickup device, when the signal charges photoelectrically converted by the light receiving unit 5 are close to the saturation signal charge amount, color mixing occurs due to the signal charges flowing from the pixels to the pixels. Is formed with a channel stopper CS.

FIGS. 10 (b) and 11 (b) show FIG.
11A and 11B show distribution diagrams of the potential に 対 す る with respect to the electrons having the structures shown in FIG. 11A and FIG. 11B, respectively. In each drawing, # 1 indicates the potential distribution before the application of the read voltage, and # 2 indicates the potential distribution after the application of the read voltage.

When a read voltage is applied to the second vertical transfer electrode TE2, the potential distribution of the impurity region existing under the second vertical transfer electrode TE2 changes. That is, as shown in FIG. 10B, in the potential distribution in the read direction, the read voltage is applied by the potential of the read gate unit 6 to the electrons, the potential of the transfer channel CH to the electrons, and the potential of the channel stopper CS to the electrons. It turns out that each goes down later.

Similarly, as shown in FIG.
In the potential distribution between the pixels arranged in the vertical direction, it is understood that the potential of the channel stopper CS with respect to the electrons decreases after the application of the read voltage.

As shown in FIG. 10B, in the read direction, when a read voltage is applied, the potential of the read gate unit 6 for electrons decreases and the potential of the transfer channel CH for electrons decreases. The signal charges e accumulated in the unit 5 are transferred to the transfer channel CH. At this time, the potential of the channel stopper CS with respect to electrons decreases,
Since the potential of the transfer channel CH with respect to the electrons also decreases, the signal charge e does not particularly flow out to the adjacent light receiving unit 5.

As shown in FIG. 11B, in the potential distribution between the pixels arranged in the vertical direction, only the potential of the channel stopper CS with respect to the electrons is substantially reduced, so that the potential is accumulated in the light receiving section 5. The potential barrier for the signal charge e decreases. In this case, the light receiving unit 5
If the signal charges accumulated in the pixel are not close to the saturation state, as shown in FIG. 11B, even after the application of the readout voltage, the signal charges flow out to the light receiving portions of the vertically adjacent pixels. It won't.

[0021]

However, FIG.
As shown in (c), when the signal charges accumulated in the light receiving unit 5 are close to the saturated state, the signal charges flow out to the light receiving unit 5 of the vertically adjacent pixel after the application of the readout voltage. This causes color mixing.

[0022] Therefore, in order to prevent color mixing between pixels in the vertical direction due to the influence of the read voltage, as shown in FIG. 12, normally, the p-type impurity 2.0 × 10 ¹² the atom
Of the channel stoppers CS formed by performing ion implantation at about s / cm ² , a channel stopper CS region formed between pixels arranged in the vertical direction further includes:
A p-type impurity of about 1.2 × 10 ¹³ atoms / cm ^2, which is five times or more, is ion-implanted, and a second channel stopper MCS having a higher p-type impurity concentration is formed at a central portion between pixels arranged in the vertical direction. To be formed.

However, as described above, in order to prevent signal charges from flowing out between adjacent pixels arranged in the vertical direction, all the pixels are uniformly ion-implanted at the above concentration. Under the influence of the second channel stopper MCS, the potential of the light receiving unit 5 with respect to the electrons is raised, and as a result, the saturation signal charge of each light receiving unit 5 decreases.

The saturation signal charge amount of each light receiving section 5 is
Can be controlled by an overflow barrier composed of a p-type region 10 below the substrate, and in order to prevent a decrease in the amount of saturated signal charge in each light receiving section 5, the substrate bias is controlled to increase the potential barrier of the overflow barrier. In this case, the difference between the potential barrier of the overflow barrier and the potential barrier of the read gate unit 6 becomes small. As a result, when the signal charges accumulated in the light receiving unit 5 reach the saturation region, the signal charges are transferred to the read gate. Part 6
, There is a problem that the smear characteristic is deteriorated due to the outflow to the transfer channel CH.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solid-state imaging device capable of preventing the occurrence of color mixture in adjacent pixels without deteriorating smear characteristics. is there.

[0026]

In order to achieve the above object, a solid-state imaging device according to the present invention is provided with a plurality of light receiving portions and a channel stopper for preventing signal charges from flowing out between the light receiving portions. A solid-state imaging device in which a plurality of color filters each having a different spectral characteristic are arranged above each light receiving unit, wherein the first light receiving unit having a color filter having the highest spectral sensitivity among the color filters; At least a part of the channel stopper formed in the periphery is formed so as to have a higher potential barrier against signal charges than the channel stoppers in other regions.

The light receiving section is formed in a matrix in the horizontal and vertical directions, has a transfer electrode extending in the horizontal direction between the light receiving sections, and has a transfer electrode around the first light receiving section. At least a portion of the channel stopper formed below the transfer electrode is formed to have the high potential barrier.

A read gate portion formed adjacent to one side of the light receiving portion; and a portion of the channel stopper formed around the first light receiving portion on the read gate portion side is formed by the read gate portion. It is formed to have a high potential barrier.

The color filter is a complementary color filter.

In the above-described solid-state imaging device of the present invention, at least a part of the channel stopper formed around the first light receiving portion having the color filter having the highest spectral sensitivity among the color filters is provided in the other region. It is formed to have a higher potential barrier to signal charges than the stopper. Accordingly, the potential barrier against the signal charge of the channel stopper formed around the first light receiving portion where the signal charge is most quickly saturated is raised, and the channel between all pixels is effectively prevented while preventing the signal charge from flowing out. The effect on the light receiving unit is reduced as compared with raising the potential barrier for the signal charge of the stopper.

Further, in order to achieve the above object, the solid-state imaging device according to the present invention is provided with a plurality of light receiving sections arranged in horizontal and vertical directions, and provided on one side of the light receiving section via a read gate section. A solid-state imaging device having a charge transfer unit and a channel stopper formed on a substrate around the light receiving unit except for the readout gate unit, and preventing a signal charge from flowing out between the light receiving units, Of the channel stoppers formed around each of the light receiving sections, a portion on the read gate section side is formed so as to have a higher potential barrier to signal charges than channel stoppers in other regions. I have.

The charge transfer section extends between the light receiving sections in the vertical direction, and covers a transfer area formed on the substrate, and covers the transfer area and the readout gate section, and is arranged in the vertical direction. A transfer electrode formed insulated on the substrate so as to extend between the light receiving portions.

A plurality of color filters having different spectral characteristics are arranged above each of the light receiving sections.

In the above-described solid-state imaging device of the present invention, of the channel stoppers formed around each light receiving portion, the portion on the read gate portion side has a smaller signal charge than the channel stoppers in other regions. It is formed to have a high potential barrier. When reading out the signal charges stored in the light receiving portion, the channel stopper existing on the read gate portion side among the channel stoppers existing between the light receiving portions arranged in the vertical direction is easily affected by the application of the read voltage. Therefore, since the channel stopper portion on the read gate portion side is formed so as to have a relatively high potential barrier for signal charges, the potential barrier at the center between vertically adjacent pixels is raised by raising the potential barrier. Rather than raising the potential barrier as a whole, the height of the barrier raised for the outflow of signal charges is reduced, and the effect on the light receiving unit is reduced.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the solid-state imaging device according to the present invention will be described below with reference to the drawings, taking a CCD solid-state imaging device using a single-plate complementary color filter as an example.

First Embodiment FIG. 1 is a diagram showing a main configuration of a solid-state imaging device according to the present embodiment. The solid-state imaging device 1 according to the present embodiment includes an imaging unit 2, a horizontal transfer unit 3, and an output unit 4. The output unit 4
For example, it has a charge-voltage converter 4a formed by a floating gate.

The image pickup section 2 includes a light receiving section 5 for performing photoelectric conversion, a readout gate section 6 and a vertical transfer section 7.
Are arranged in the form of a planar matrix. The pixels 8 are separated from each other by a channel stopper to be described later so as not to cause electrical interference.

The vertical transfer units 7 are shared for each column of the light receiving units 5 and are arranged in a predetermined number. The four-phase clock signals φV1 and φV for driving the vertical transfer unit 7 are supplied to the imaging unit 2.
2, φV3, φV4 are input. Two-phase clock signals φH1 and φH2 for driving the horizontal transfer unit 3 are input.

The above-described horizontal transfer unit 3 and vertical transfer unit 7
A potential well of a minority carrier formed by introducing an impurity into the surface side of a semiconductor substrate; and a plurality of electrodes (transfer electrodes) repeatedly formed on a substrate with an insulating film interposed therebetween so as to be insulated and separated from each other. It is composed of These transfer units 3 and 7 have the above-mentioned clock signals φV1, φV2, φV3, φV4, φH1,
φH2 is applied with a phase shift periodically.
These transfer units 3 and 7 are controlled by a clock signal applied to the transfer electrode, the potential distribution of the potential well changes sequentially, and transfer the charges in the potential well in the direction of the phase shift of the clock signal, that is, a so-called shift register. Function as

FIG. 2 shows an example of the configuration of a complementary color filter installed in the imaging section 2 in the solid-state imaging device shown in FIG.

As shown in FIG. 2, in the solid-state imaging device according to this embodiment, cyan (C
y), yellow (Ye), green (G), magenta (Mg)
Are arranged as shown. That is, cyan (Cy) and yellow (Ye) are repeatedly arranged in this order in the horizontal direction, and in the next row, green (G) and magenta (Mg) are repeatedly arranged in this order in the horizontal direction. .
Further, in the next line, cyan (C
y) and yellow (Ye) are repeatedly arranged in this order in the horizontal direction. In the next row, the magenta (M
g) and green (G) are repeatedly arranged in the horizontal direction. Similarly, in a region (not shown), cyan (Cy) and yellow (Ye) are repeatedly arranged in this order in the horizontal direction, and green (G) and magenta (M)
g) are arranged with their order alternately reversed.

As shown in FIG. 2, when an on-chip color filter is configured, in this embodiment,
A second channel stopper MCS having a higher p-type impurity concentration is provided in a channel stopper existing between the pixel 8 having the filter for yellow (Ye) and pixels arranged adjacently in the vertical direction.

FIG. 3 is a plan view of a main part of a pixel portion of a CCD solid-state imaging device using the above-mentioned single-plate type complementary color filter. FIG. 4A is a cross-sectional view taken along the line CC ′ in the vertical direction of the pixel on which the yellow filter of FIG. 3 is formed. FIG. 10A is a diagram showing A- in the horizontal direction of FIG.
FIG. 11A is a cross-sectional view along the line A ′, and FIG. 11A is a cross-sectional view along the line BB ′ in the vertical direction of FIG.

In a p-type silicon substrate or a p-type well (hereinafter referred to as a substrate) 10 formed in the silicon substrate, for example, an n-type impurity region 11 or the like is formed.
The photoelectric conversion is performed in a region centered on the pn junction between the light-receiving portion and the light-receiving portion 5 for generating signal charges and accumulating the signal charges for a certain period of time. In addition, a high-concentration p-type impurity region 1 is formed on the surface of n-type impurity region 11.
2 is formed, whereby the photodiode is formed not on the surface but on the bulk side, thereby forming a buried photodiode.

The substrate 10 is made of, for example, an n-type impurity region and has a transfer channel CH for transferring signal charges.
Are formed parallel to the light receiving units 5 arranged in the vertical direction. The transfer channel CH is formed at a predetermined distance from the light receiving units 5 on both sides.

Between the light receiving section 5 and the transfer channel CH, for example, a read gate section 6 made of a p-type impurity region is formed. The read gate unit 6 is formed separately for each cell in the same column, and forms a variable potential region between the light receiving unit 5 and one transfer channel CH.

A channel stopper CS made of a high-concentration p-type impurity region is formed along the other three sides of the light-receiving portion 5 except for the region where the readout gate portion 6 is formed, to a deep portion of the substrate. The channel stopper CS prevents signal charges generated in the light receiving unit 5 from flowing out to different pixels.

As shown in FIGS. 3 and 4 (a), the channel stoppers CS above and below the pixel 8 having the yellow (Ye) filter have a higher p-type impurity concentration. The channel stopper MCS is formed to a deep part of the substrate.

A first vertical transfer electrode TE1 made of polysilicon of the first layer is interposed between the light receiving sections 5 via an insulating film 20 such as a silicon oxide film so as to be orthogonal to the transfer channel CH.
Is formed by stretching. First vertical transfer electrode TE1
Has a rectangular shape slightly extending in the transfer channel direction at a portion overlapping with the transfer channel CH and the read gate unit 6.

Further, a second vertical transfer electrode TE2 made of polysilicon of the second layer is formed extending between the light receiving portions 5 orthogonally to the transfer channel CH. The second vertical transfer electrode TE2 has a rectangular shape greatly extending on the transfer channel on the opposite side of the lower layer of the first vertical transfer electrode TE1 at a portion overlapping the transfer channel CH and the read gate unit 6.

As shown in FIG. 3, in the direction in which the transfer channel CH is formed, a second vertical transfer electrode TE2 is formed between the first vertical transfer electrodes TE1 with an insulating film 21 interposed therebetween. The end of the electrode TE2 overlaps the first vertical transfer electrode TE1.

The insulating film 2 is formed on the second vertical transfer electrode TE2.
The light-shielding film 30 made of a metal such as aluminum or tungsten is formed in a state where the metal film 1 is interposed. The light-shielding film 30 is open above the light receiving unit 5.

Although not shown, the entire surface covered with the light shielding film 30, for example, PSG (Phosphosilicate glass),
An upper interlayer insulating film made of BPSG (Borophosphosilicate glass), silicon oxide, silicon nitride, or the like is formed, and the surface of the interlayer insulating film is planarized. The interlayer insulating film may be a laminate of insulating films made of the above materials.

Although not shown, an on-chip color filter (OCC) is provided on the flattened surface of the interlayer insulating film.
F). On-chip color filters are
As shown in FIG. 2, for example, it is configured by a complementary color filter, and is colored, for example, any of cyan (Cy), magenta (Mg), yellow (Ye), and green (G). . Further, although not shown, an on-chip lens (OCL) made of a light-transmitting material such as a negative photosensitive resin is arranged on the on-chip color filter. Light received by the lens surface (convex upper curved surface) of the on-chip lens is collected, a specific wavelength region is selected by the on-chip color filter, and is incident on the light receiving unit 5.

FIG. 5 shows yellow (Ye) and cyan (C
FIG. 6 is a graph showing the spectral transmission characteristics of each of the filters y), magenta (Mg), and green (G). FIG. 6 is a graph showing the relationship between the amount of incident light and the amount of accumulated signal charge in a pixel having each filter. Is shown. Note that the spectral transmission characteristics shown in FIG. 5 do not take into account the characteristics of the on-chip lens and the characteristics of the light source.

As shown in FIG. 5, the light transmittance of each filter is different for each color. That is, yellow (Y
e), cyan (Cy), magenta (Mg), and green (G) filters have different wavelengths of light to pass and different amounts of light to pass.

As a result, as shown in FIG. 6, the amount of signal charge stored in the light receiving portion differs between the pixels having each filter with respect to the amount of incident light. In particular,
In FIG. 5, the area of each graph is an index of the sensitivity of the filter. As shown in FIG. 6, the pixel having the largest area of the graph shown in FIG. The largest charge. Hereinafter, it is understood that the sensitivity is higher in the order of magenta (Mg), cyan (Cy), and green (G) pixels.

Therefore, in each pixel, the saturation signal charge D
It can be understood that the pixel that has the yellow filter is the one that reaches the saturation signal charge D at the earliest, and similarly, the pixels that reach the saturation signal charge amount D are magenta (Mg), cyan (Cy),
It can be seen that green (G) pixels are ordered earlier.

In the solid-state imaging device according to the present embodiment, the pixels 8 constituting the yellow (Ye) having the highest sensitivity are arranged adjacent to each other in the vertical direction in consideration of the sensitivity of the pixels constituting the respective colors. The second channel stopper MCS having a higher p-type impurity concentration is provided only in the channel stopper existing between the pixel and the selected pixel.

FIGS. 4 (b), 10 (b) and 11
4 (a), FIG. 10 (a) and FIG.
2A and 2B show distribution diagrams of the potential に 対 す る for electrons having the structure shown in FIG. In each figure, # 1 indicates the potential distribution before the application of the read voltage, and # 2
Indicates the potential distribution after the application of the read voltage.

In the read direction, as shown in FIG. 10B, when a read voltage is applied, the potential of the read gate unit 6 for electrons decreases and the potential of the transfer channel CH for electrons decreases. The signal charges e accumulated in the unit 5 are transferred to the transfer channel CH. At this time, the potential of the channel stopper CS with respect to electrons decreases,
Since the potential of the transfer channel CH with respect to the electrons also decreases, the signal charge e does not particularly flow out to the adjacent light receiving unit 5.

In the vertical direction, as shown in FIG. 11 (b), only the potential of the channel stopper CS with respect to the electrons is substantially reduced.
Since the relative sensitivity is low, the signal charge e accumulated in the light receiving unit 5 hardly becomes almost saturated, and the signal charge flows out to the light receiving unit 5 of a vertically adjacent pixel. Almost no.

On the other hand, in the vertical direction of the yellow pixel which has high sensitivity and is most likely to reach the saturation signal charge amount, as shown in FIG. Since the barrier against electrons is raised by the formation of the second channel stopper MCS, even if the amount of the signal charge e is close to the saturation state, the electrons are blocked to the light receiving portion after the read voltage is applied. Therefore, it is possible to prevent the signal charge e from flowing out to the light receiving section 5 of the pixel adjacent in the vertical direction.

As described above, in the solid-state imaging device according to the present embodiment, since the relative sensitivity of the pixels having each color filter is different in the solid-state imaging device using a single-plate complementary color filter, the saturation signal charge By providing an even higher density second channel stopper MCS in the vertical direction of the light receiving section 5 in the yellow pixel which reaches the amount fastest, signal charges are prevented from flowing out between pixels in the vertical direction of all colors. Therefore, as compared with the case where the second channel stopper MCS is formed, the influence on the light receiving section 5 can be reduced, and the smear characteristic does not deteriorate.
It is possible to effectively prevent the occurrence of color mixing due to outflow of signal charges between pixels.

Next, a method of manufacturing the solid-state imaging device according to the present embodiment will be described, focusing on the step of forming a channel stopper. That is, an ion implantation mask having a predetermined pattern such as a resist is formed on the silicon substrate 10 and a p-type impurity is implanted at a dose of 2.0 × 10 ¹² at.
By ion implantation at about oms / cm ² , a channel stopper CS is formed in the region shown in FIG. Then, the ion implantation mask is removed, and an ion implantation mask having another pattern is formed.
By performing ion implantation of about × 10 ¹³ atoms / cm ² , p
Channel stopper MCS with higher impurity concentration
Is formed above and below a pixel that will later become a yellow pixel.

Thereafter, by performing ion implantation under predetermined conditions, the light receiving section 5 is formed, the transfer channel CH is formed, and the read gate section 6 is formed. Then, an insulating film 20 made of silicon oxide or the like is formed on the surface of the substrate 10 on which the various impurity regions are formed, and a first polysilicon layer is deposited on the insulating film 20 and patterned to form a first polysilicon layer.
The vertical transfer electrode TE1 is formed. Then, the first vertical transfer electrode TE1 is oxidized to form an insulating film 21 made of silicon oxide on the surface of the first electrode 11, and a second polysilicon layer is deposited and patterned on the insulating film 21. Second
The vertical transfer electrode TE2 is formed.

Next, an insulating film 21 is deposited on the second vertical transfer electrode TE2. For example, tungsten, aluminum, or the like is deposited on the insulating film 21 and patterned to have an opening above the light receiving section 5. The light shielding film 30 is formed.

Subsequently, after forming an interlayer insulating film (not shown), a color filter composed of cyan (Cy), magenta (Mg), yellow (Ye), and green (G) is formed by, for example, a dyeing method. In the dyeing method, a photosensitive agent is added to a polymer such as casein and applied, and exposure, development, dyeing and fixing are repeated for each color. Alternatively, the on-chip color filter may be formed by using a dispersion method, a printing method, an electrodeposition method, or the like. Finally, by forming an on-chip lens, the solid-state imaging device according to the present embodiment can be formed.

The solid-state imaging device according to the present embodiment has the above-described effects only by adding an ion implantation mask for forming the second channel stopper MCS and an ion implantation process in addition to the ordinary process. A solid-state imaging device can be manufactured.

Second Embodiment FIG. 7 is a plan view of a main part of a pixel portion of a solid-state imaging device according to the present embodiment. In the present embodiment, the second channel stopper MC is conventionally provided at the center between pixels arranged in the vertical direction.
The S is formed so as to be shifted from the central portion to the read gate portion 6 side in comparison with the case where S is formed. Then, in the present embodiment, the second channel stopper MCS is not formed only in the yellow pixel as compared with the first embodiment,
A second channel stopper MCS is formed for all pixels.

The operation of the solid-state imaging device according to this embodiment having the above configuration will be described. At the time of reading the charge, a read voltage is applied to the second vertical transfer electrode TE2 which largely covers the read gate portion 6 formed adjacent to one side of the light receiving portion 5, When the read voltage is applied, the potential of the read gate unit 6 made of the p-type impurity region with respect to electrons decreases, so that the signal charges accumulated in the light receiving unit 5 are transferred to the transfer channel CH.

At this time, as described with reference to FIG. 11B, the channel stopper CS formed between the vertically arranged pixels that exists under the second vertical transfer electrode TE2.
Of the channel stopper CS adjacent to the read gate unit 6, that is,
The barrier of the channel stopper CS is lowered from the reading direction side. As a result, when the signal charge flows out, there is a strong possibility that the signal charge will flow out of the channel stopper existing on the read gate unit 6 side.

Therefore, the second channel stopper MCS is formed in the channel stopper CS portion of the region adjacent to the read gate section 6 to strengthen the portion where the potential barrier is likely to decrease when the read voltage is applied, so that the portion adjacent to the read gate portion 6 in the vertical direction is reduced. As compared with forming a second channel stopper at the center between the pixels to be formed and raising the potential barrier as a whole, the impurity concentration required for preventing color mixing can be reduced, and the influence on the light receiving unit 5 can be reduced. Can be reduced. As described above, since the influence on the light receiving unit 5 can be reduced, even if the second channel stopper MCS is formed between all the pixels arranged in the vertical direction, the smear characteristic deteriorates compared to the related art. Can be suppressed.

Therefore, according to the present embodiment, since the second channel stopper MCS is formed in the channel stopper CS portion of the region adjacent to the readout gate portion 6, the second channel stopper MCS is formed at the center between pixels arranged in the vertical direction. As compared with the case where the channel stopper MCS is formed, the impurity concentration required to prevent signal charges from flowing out between pixels in the vertical direction is reduced, and as a result, the influence on the light receiving unit 5 can be reduced. As a result, it is possible to prevent color mixture between pixels arranged in the vertical direction without deteriorating smear characteristics.

Third Embodiment FIG. 8 is a plan view of a main part of a pixel portion of a solid-state imaging device according to the third embodiment . The present embodiment has a structure in which the first embodiment and the second embodiment are combined. That is, similarly to the second embodiment, the second channel stopper MCS
And a pixel having a filter for yellow (Ye) while being shifted from the center toward the readout gate section 6,
The second channel stopper MCS is formed only in the channel stopper existing between the pixel and the pixel arranged adjacently in the vertical direction.

According to the solid-state imaging device of the present embodiment having the above-described configuration, the second channel stopper MCS is formed so as to be shifted in the readout direction from the center between the pixels arranged in the vertical direction so that the pixels between the pixels in the vertical direction are shifted. The second channel stopper MCS is provided only in the vertical direction of the light receiving section 5 in the yellow pixel which reaches the saturated signal charge amount fast, while reducing the impurity concentration for preventing the outflow of the signal charge. The influence on the portion 5 can be further reduced, and the occurrence of color mixture between pixels can be effectively prevented without deteriorating the smear characteristics.

The present invention is not limited to the above embodiment. For example, in the present embodiment, a single-plate complementary color filter, in particular, a cyan (C) color filter as shown in FIG.
y), magenta (Mg), yellow (Ye), green (G)
Has been described using a complementary color filter having an array of white (W), cyan (Cy), green (G), and yellow (Ye).
In particular, if a complementary color filter using yellow (Ye) having a high light transmittance is used, such as a complementary color filter composed of Further, in particular, in the second embodiment, the color filter is not limited to a single-plate type complementary color filter, and a single-plate type color filter composed of primary color red (R), green (G), and blue (B). It is also applicable to a solid-state imaging device having The arrangement of each color filter is not particularly limited. In addition, various changes can be made without departing from the gist of the present invention.

[0078]

According to the solid-state imaging device of the present invention, it is possible to prevent the occurrence of color mixing in adjacent pixels without deteriorating smear characteristics.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a main configuration of a solid-state imaging device according to an embodiment.

FIG. 2 is a diagram illustrating an example of a configuration of an on-chip color filter provided in an imaging unit in the solid-state imaging device illustrated in FIG.

FIG. 3 is a plan view of a main part of a pixel unit of the CCD solid-state imaging device according to the embodiment;

4A is a cross-sectional view along a line CC ′ of a pixel in which the yellow filter of FIG. 3 is formed, and FIG. 4B is a cross-sectional view of the pixel having the structure shown in FIG. FIG. 4 is a distribution diagram of a potential ψ.

FIG. 5 is a graph showing spectral transmission characteristics of each of yellow (Ye), cyan (Cy), magenta (Mg), and green (G) filters.

FIG. 6 is a graph showing a relationship between a signal charge amount and a light amount of each pixel having a filter of each color.

FIG. 7 is a plan view of a main part of a pixel unit of a solid-state imaging device according to a second embodiment.

FIG. 8 is a plan view of a main part of a pixel unit of a solid-state imaging device according to a third embodiment.

FIG. 9 is a plan view of a main part of a pixel portion of a CCD solid-state imaging device using a single-plate type color filter according to a conventional example.

FIG. 10A is a cross-sectional view taken along a line AA ′ in FIG. 9;
FIG. 4B is a cross-sectional view taken along a line, and FIG. 4B is a distribution diagram of the potential に 対 す る with respect to the electrons having the structure shown in FIG.

FIG. 11A is a view taken along the line BB ′ in the vertical direction of FIG.
It is sectional drawing along a line, (b) and (c) are
FIG. 4 is a distribution diagram of a potential に 対 す る for electrons having the structure shown in FIG.

FIG. 12 is a plan view of a main part of a pixel portion for explaining a problem of a CCD solid-state imaging device using a single-plate type color filter according to a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Solid-state imaging device, 2 ... Imaging part, 3 ... Horizontal transfer part, 4 ...
Output section, 4a: charge-voltage conversion section, 5: light receiving section, 6: readout gate section, 7: vertical transfer section, 8: pixel, 10: substrate, 11: n-type impurity area, 12: p-type impurity area, 2
0: insulating film, 21: insulating film, 30: light shielding film, TE1: first vertical transfer electrode, TE2: second vertical transfer electrode, CH: transfer channel, CS: channel stopper, MCS: second channel stopper, # 1 ... Potential before read voltage application, # 2 ... potential after read voltage application.

Claims (7)

[Claims] 1. A plurality of light receiving portions, and a channel stopper for preventing signal charges from flowing out between the light receiving portions are formed, and a plurality of color filters having different spectral characteristics are arranged above each light receiving portion. Wherein at least a portion of the channel stopper formed around a first light receiving portion having a color filter having the highest spectral sensitivity among the color filters is a channel stopper in another region. A solid-state imaging device formed so as to have a higher potential barrier to signal charges as compared to. 2. The light-receiving unit has a transfer electrode formed in a matrix in the horizontal and vertical directions, and has a transfer electrode extending in a horizontal direction between the light-receiving units. The solid-state imaging device according to claim 1, wherein at least a part of the channel stopper formed below the transfer electrode in the periphery is formed to have the high potential barrier. 3. A read gate section formed adjacent to one side of the light receiving section, and a portion of the channel stopper formed around the first light receiving section on the read gate section side. The solid-state imaging device according to claim 1, wherein the device is formed to have the high potential barrier. 4. The solid-state imaging device according to claim 1, wherein said color filter is a complementary color filter. 5. A solid-state imaging device comprising: a plurality of light receiving units arranged in a horizontal direction and a vertical direction; and a charge transfer unit provided on one side of the light receiving unit via a readout gate unit. A channel stopper formed on a substrate around the light receiving unit except for the readout gate unit and preventing outflow of signal charges between the light receiving units, among the channel stoppers formed around each of the light receiving units; A solid-state imaging device wherein a portion on the read gate portion side is formed to have a higher potential barrier for signal charges than a channel stopper in another region. 6. The charge transfer section, which extends vertically between the light receiving sections and covers a transfer area formed on the substrate, and covers the transfer area and the readout gate section, and is arranged in a vertical direction. The solid-state imaging device according to claim 5, further comprising: a transfer electrode formed insulated on the substrate so as to extend between the light receiving units. 7. The solid-state imaging device according to claim 5, wherein a plurality of color filters having different spectral characteristics are arranged above each of said light receiving sections.