JPH11168206A - Solid-state image pick-up device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly reduce potential formed between electric charge transfer electrodes by making different the impurity concentration of an impurity region between vertical electric charge transfer electrodes and between horizontal electric charge transfer electrodes from that of the impurity region between each vertical electric charge transfer electrodes or between each horizontal electric charge transfer electrodes. SOLUTION: A solid-state image pick-up device consists of a photoelectric conversion part 10, a vertical electric charge transfer part 20, and a horizontal electric charge transfer part 30, and the vertical electric charge transfer part 20 and the horizontal electric charge transfer part 30 have a single-layer electrode structure. Then, a first N-type semiconductor region with an impurity concentration of, for example, approximately 9.7×10<16> cm<3> is formed between the electric charge transfer electrodes that become the connection region between the vertical electric charge transfer part 20 and the horizontal electric charge transfer part 30, and a second N-type semiconductor region with an impurity concentration of, for example, approximately 9.5×10<16> cm<3> is formed between the electrode transfer electrodes of the vertical transfer part 20. Further, a third N-type semiconductor region with an impurity concentration of, for example, approximately 9.0 × 10<16> cm<3> is formed between the electric charge transfer electrodes of the horizontal electric charge transfer part 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a solid-state imaging device having a vertical charge transfer section and a horizontal charge transfer section in which charge transfer electrodes are formed at predetermined intervals, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, with the progress of microfabrication technology, a single-layer conductive electrode material has been etched using a single-layer conductive electrode material to form a single-layer electrode structure having an interelectrode distance of 0.2 to 0.3 μm. A charge transfer device can now be formed. The charge transfer device having a single-layer electrode structure has advantages that the interlayer capacitance is small and there is no problem of insulation between the electrodes because there is no overlapping portion between the electrodes. Further, since it is not necessary to oxidize the electrode in order to form an interlayer film, a metal film or a silicide film thereof can be used in addition to polycrystalline silicon as an electrode material, and there is an advantage that the resistance of the electrode can be reduced. .

FIG. 11 is a plan view of a single-layer electrode 4-phase drive and 2-phase drive charge transfer device corresponding to a vertical charge transfer section and a horizontal charge transfer section of a conventional solid-state imaging device.

[0004] In FIG. 11, N-type semiconductor region serving as a charge transfer unit 102, N formed between the charge transfer electrodes of the vertical charge transfer portion 105 ^- -type semiconductor region, N-type semiconductor 109 serving as a photoelectric conversion portion Region, 110 is a P-type semiconductor region serving as a signal readout unit, 111 is a P ⁺ -type semiconductor region serving as an element isolation unit, 112a, b, c, and d are charge transfer electrodes of a vertical charge transfer unit, and 113a and b are horizontal charges. This is a charge transfer electrode of the transfer unit. The charge transfer electrodes of the vertical charge transfer section and the horizontal charge transfer section are formed with a gap of about 0.3 μm.

FIG. 12 is a cross-sectional view of a single-layer electrode four-phase drive and two-phase drive charge transfer device corresponding to a vertical charge transfer portion and a horizontal charge transfer portion of a conventional solid-state imaging device in respective manufacturing steps. It is a thing.

First, an impurity concentration of the opposite conductivity type is set to 1 in a P-type semiconductor substrate 101 having an impurity concentration of about 1 × 10 ¹⁶ cm ^−3.
Forming an N-type semiconductor region 102 of about × 10 ¹⁷ cm ^-3 ,
By performing thermal oxidation, a first oxide film 103 having a thickness of about 30 nm is formed (FIG. 12A).

Further, after a desired region of the N-type semiconductor region 102 of the horizontal charge transfer portion and a first oxide film 103 of the N-type semiconductor region 102 of the vertical charge transfer portion are removed by photolithography and etching, By performing thermal oxidation again, a second oxide film 104 of about 60 nm is formed. At this time, the first oxide film 103 formed in a desired region of the N-type semiconductor layer 102 in the horizontal charge transfer portion has a thickness of about 70 nm (FIG. 12B).

Next, the first oxide film 103 and the second
And the charge transfer electrodes 112a, b, c, and d of the vertical charge transfer portion and the charge transfer electrode 113a of the horizontal charge transfer portion made of a polycrystalline silicon film at an interval of 0.3 μm by a known technique via the oxide film 104. , B (FIG. 12)
(C)).

Subsequently, the charge transfer electrode 112 of the vertical charge transfer portion made of the polycrystalline silicon film is formed by using a photo-etching method.
a, b, c, and d, between the charge transfer electrodes 113a and 113b of the horizontal charge transfer unit, and between the charge transfer electrode 112d of the vertical charge transfer unit and the charge transfer electrode 113a of the horizontal charge transfer unit. By introducing an impurity (for example, boron) of the opposite conductivity type to the N-type semiconductor region 102 in a self-aligned manner by an ion implantation method, an N ⁻ -type semiconductor region 105 having an impurity concentration of about 9.0 × 10 ¹⁶ cm ⁻³ is obtained. Forming (FIG. 12)
(D)).

Thereafter, the interlayer insulating film 11 is formed by a known technique.
4, the charge transfer electrode 112a of the vertical charge transfer unit,
b, c, d and the charge transfer electrode 113 of the horizontal charge transfer section
A conventional charge transfer device can be obtained by connecting a and b with the metal wiring 115 (FIG. 12E).

Generally, in such a solid-state imaging device, each of the charge transfer electrodes 2a, 2b, 2c, and 2d of the vertical charge transfer section has an amplitude of about 0 to -8 V and a phase shift of 90 degrees. By applying the applied drive pulse to each electrode, a drive pulse having an amplitude of about 0 to 5 V and a phase shift of 180 degrees is applied to each of the charge transfer electrodes 3a and 3b of the horizontal charge transfer section. It is driven by.

[0012]

However, in the solid-state imaging device described above, the absolute value and amplitude of the driving pulse may be different between the vertical charge transfer unit and the horizontal charge transfer unit. In some cases, the channel width or the electrode interval between the charge transfer unit and the horizontal charge transfer unit is different.

In such a case, the vertical charge transfer portion, the horizontal charge transfer portion, and the depth of the potential formed between the charge transfer electrodes differ between the vertical charge transfer portion and the horizontal charge transfer portion. Becomes That is, when the charge transmission electrodes are present at intervals, a potential is formed in the gap, and the potential becomes deeper as the interval increases (FIG. 13A,
(B)). In addition, the shape and depth of the potential change depending on the potential applied between the electrodes. If the potential difference is large, a shallow potential is formed due to the potential modulation effect (FIG. 13C).

On the other hand, in the above-mentioned conventional example, the potential potential is reduced by introducing ions of the opposite conductivity type. However, the reduction of the potential potential by the ion implantation also causes a potential barrier if the amount of implantation is too large. There is an optimum value for the injection amount. For example, in FIGS. 14A and 14B, Ф ′ is the optimum injection amount. 14A shows a case where there is no potential difference, and FIG. 14B shows a case where there is a potential difference.

[0015] However, in the conventional example described above, N by introducing all self-aligned manner N-type semiconductor region and the opposite conductivity type impurity between the charge transfer electrodes (e.g., boron) in the ion implantation method ^- -type semiconductor region Therefore, it is difficult to uniformly reduce the potential between all the charge transfer electrodes. For this reason, there is still room for improvement in terms of charge transfer efficiency, such as occurrence of signal charge transfer residue.

An object of the present invention is to uniformly reduce potential potentials formed between respective charge transfer electrodes between a vertical charge transfer section, a horizontal charge transfer section, and between a vertical charge transfer section and a horizontal charge transfer section. Another object of the present invention is to provide a solid-state imaging device having excellent charge transfer efficiency and a method of manufacturing the same.

[0017]

According to the present invention for solving the above problems, a photoelectric conversion unit, a vertical charge transfer unit for vertically transferring charges generated in the photoelectric conversion unit, and a vertical charge transfer unit A plurality of vertical charge transfer electrodes provided in the vertical charge transfer unit, the plurality of vertical charge transfer electrodes being provided in the vertical charge transfer unit. The first provided between the electrodes
An impurity region, a plurality of horizontal charge transfer electrodes provided in the horizontal charge transfer portion, a second impurity region provided between the horizontal charge transfer electrodes, the vertical charge transfer electrode and the horizontal charge transfer. A third impurity region provided between the electrodes, wherein the impurity concentration of the third impurity region is different from at least the impurity concentration of one of the first and second impurity regions. An imaging device is provided.

It is preferable that the impurity concentration of the third impurity region is higher than at least one of the first and second impurity regions.

Further, the impurity concentration of the third impurity region is different from the impurity concentration of one of the first and second impurity regions and substantially equal to the other impurity concentration of the first and second impurity regions. It is also preferable that they are identical. Further, it is preferable that the impurity concentration of the third impurity region is higher than the one of the first and second impurity regions.

It is preferable that the first, second and third impurity regions have different impurity concentrations. Further, the impurity concentration of the first impurity region is preferably higher than the impurity concentration of the second impurity region, and the impurity concentration of the second impurity region is preferably higher than the impurity concentration of the third impurity region. .

Further, according to the present invention, a photoelectric conversion unit;
In a solid-state imaging device including a vertical charge transfer unit and a horizontal charge transfer unit, the vertical charge transfer unit includes a plurality of first conductivity regions of one conductivity type and a plurality of first impurity regions on an insulation film. A plurality of vertical charge transfer electrodes respectively provided between the plurality of first impurity regions, and a plurality of second impurity regions of the one conductivity type provided between the plurality of first impurity regions, respectively. A plurality of conductive third impurity regions, a plurality of horizontal charge transfer electrodes provided on the plurality of third impurity regions via an insulating film, and a plurality of third impurity regions provided between the plurality of third impurity regions, respectively. There is provided a solid-state imaging device including the plurality of fourth impurity regions of the one conductivity type, wherein an impurity concentration of the second impurity region is different from an impurity concentration of the fourth impurity region.

The semiconductor device may further include a fifth impurity region of the one conductivity type provided between the first impurity region and the third impurity region, wherein the impurity concentration of the fifth impurity region is
Preferably, at least one of the second and fourth impurity regions has a different impurity concentration. Further, the impurity concentration of each of the first and third impurity regions is higher than the impurity concentration of the fifth impurity region, and the impurity concentration of the fifth impurity region is at least one of the second and fourth impurity regions. Preferably, it is higher than the concentration. It is also preferable that the first, second, fourth, and fifth impurity regions have different impurity concentrations. Further, the impurity concentration of the first impurity region and the impurity concentration of the third impurity region are substantially the same, and the impurity concentration of the second impurity region and the impurity concentration of the fifth impurity region are substantially equal. The impurity concentration of the first and third impurity regions is higher than the impurity concentration of the second and fifth impurity regions, and the impurity concentration of the second and fifth impurity regions is the same as that of the fourth impurity region. It is also preferable that the concentration be higher than the concentration.
Further, the impurity concentration of the first impurity region and the impurity concentration of the third impurity region are substantially the same,
The impurity concentration of the impurity region is substantially the same as the impurity concentration of the fifth impurity region. The impurity concentration of the first and third impurity regions is higher than the impurity concentration of the second impurity region. The impurity concentration of the impurity region is the fourth
It is also preferable that the impurity concentration is higher than the impurity concentration of the fifth impurity region. The first, second and third impurity regions have the same impurity concentration, and the fourth and fifth impurity regions have the same impurity concentration.
Preferably, the impurity concentration of the impurity regions is the same as each other, and the impurity concentration of the first, second and third impurity regions is higher than the impurity concentration of the fourth and fifth impurity regions. Further, the first, second, third and fifth impurity regions have the same impurity concentration, and the first, second, third and fifth impurity regions have the same impurity concentration as the fourth impurity region. It is also preferable that the impurity concentration is higher than the impurity concentration.

Furthermore, according to the present invention, a step of forming an impurity region of the opposite conductivity type in a semiconductor substrate of one conductivity type, a step of forming an insulating film on the semiconductor substrate, Forming vertical charge transfer electrodes and a plurality of horizontal charge transfer electrodes, and covering the vertical charge transfer electrodes and the horizontal charge transfer electrodes with a mask covering between the vertical charge transfer electrodes and between the horizontal charge transfer electrodes. Introducing the impurity of the one conductivity type into the impurity region between the vertical charge transfer electrodes, and covering the space between the horizontal charge transfer electrodes and the space between the vertical charge transfer electrodes and the horizontal charge transfer electrodes with a mask. Introducing the one-conductivity-type impurity into the impurity region between the vertical charge-transfer electrodes and the vertical charge-transfer electrodes and between the horizontal charge-transfer electrodes with a mask. Introducing the impurity of the one conductivity type into the impurity region between the electrodes, whereby the impurity region between the vertical charge transfer electrode and the horizontal charge transfer electrode, between the respective vertical charge transfer electrodes There is provided a method for manufacturing a solid-state imaging device, wherein impurity concentrations of an impurity region and an impurity region between the horizontal charge transfer electrodes are different from each other.

According to the invention, a step of forming an impurity region of the opposite conductivity type in a semiconductor substrate of one conductivity type, a step of forming an insulating film on the semiconductor substrate, Forming the vertical charge transfer electrode and the plurality of horizontal charge transfer electrodes, and introducing the one conductivity type impurity into the impurity region using the plurality of vertical charge transfer electrodes and the plurality of horizontal charge transfer electrodes as a mask. And covering the space between the vertical charge transfer electrodes and the horizontal charge transfer electrodes with a mask and introducing the one conductivity type impurity into the impurity regions between the vertical charge transfer electrodes and between the horizontal charge transfer electrodes. And covering the space between the vertical charge transfer electrodes and the space between the vertical charge transfer electrodes and the horizontal charge transfer electrodes with a mask, and forming the one conductivity type impurity in the impurity region between the horizontal charge transfer electrodes. Method for manufacturing a solid-state imaging device and a step of introducing is provided.

According to the invention, a step of forming an impurity region of the opposite conductivity type in a semiconductor substrate of one conductivity type, a step of forming an insulating film on the semiconductor substrate, Forming a vertical charge transfer electrode and a plurality of horizontal charge transfer electrodes, and covering between the horizontal charge transfer electrodes with a mask, between the vertical charge transfer electrodes and between the vertical charge transfer electrode and the horizontal charge transfer electrode. Introducing the one-conductivity-type impurity into the impurity region, and covering the space between the vertical charge transfer electrodes and the space between the vertical charge transfer electrode and the horizontal charge transfer electrode with a mask between the horizontal charge transfer electrodes. Introducing the one conductivity type impurity into the impurity region.

Further, according to the present invention, a step of forming a reverse conductivity type impurity region in a semiconductor substrate of one conductivity type, a step of forming an insulating film on the semiconductor substrate, Forming a vertical charge transfer electrode and a plurality of horizontal charge transfer electrodes, and covering the space between the horizontal charge transfer electrodes and the space between the vertical charge transfer electrode and the horizontal charge transfer electrodes with a mask. Introducing the one-conductivity-type impurity into the impurity region, and covering between the vertical charge transfer electrodes with a mask, between the horizontal charge transfer electrodes, and between the vertical charge transfer electrodes and the horizontal charge transfer electrodes. Introducing the one conductivity type impurity into the impurity region.

Further, according to the present invention, there are provided a vertical charge transfer section and a horizontal charge transfer section in which single-layer charge transfer electrodes are formed at predetermined intervals on a first conductivity type semiconductor substrate via an insulating film. In the solid-state imaging device, a gap between a first first conductivity type semiconductor region provided in a connection region between the vertical charge transfer unit and the horizontal charge transfer unit, and each charge transfer electrode of the vertical charge transfer unit And a third first conductivity type semiconductor region provided in a gap between the charge transfer electrodes of the horizontal charge transfer portion, wherein the first first conductivity type semiconductor region is provided in The impurity concentration of the first conductivity type semiconductor region, the second first conductivity type semiconductor region, and the third first conductivity type semiconductor region are different from each other, and when the driving voltage is applied, each charge transfer electrode of the vertical charge transfer unit is applied. The potential formed between them, The potential potential formed between the charge transfer electrodes of the flat charge transfer portion and the potential potential formed in the connection region between the vertical charge transfer portion and the horizontal charge transfer portion have substantially the same depth. , The first
A solid-state imaging device, wherein the first conductive type semiconductor region, the second first conductive type semiconductor region, and the third first conductive type semiconductor region are set to have impurity concentrations.

[0028]

Embodiments of the present invention will be described below with reference to examples.

Referring to FIG. 1 showing a solid-state imaging device according to one embodiment of the present invention, a solid-state imaging device according to this embodiment includes a photoelectric conversion unit 10, a vertical charge transfer unit 20, and a horizontal charge transfer unit 30. Become. The vertical charge transfer unit 20 and the horizontal charge transfer unit 30 have a single-layer electrode structure. Vertical charge transfer unit 20
Is driven by a driving pulse composed of a four-phase clock, and charges generated in the photoelectric conversion unit 10 are transferred to the horizontal charge transfer unit 3.
Transfer to 0. The horizontal charge transfer unit 30 is driven by a driving pulse composed of a two-phase clock, and
The charge transferred from 0 is transferred to an output terminal (not shown).

In FIG. 1, reference numeral 102 denotes an N-type semiconductor region serving as a charge transfer portion; 106, a first N ^- type semiconductor region formed between the charge transfer electrodes of the vertical charge transfer portion and the horizontal charge transfer portion; A second N ⁻ type semiconductor region formed between the charge transfer electrodes of the vertical charge transfer unit, 108 is a third N ⁻ type semiconductor region formed between the charge transfer electrodes of the horizontal charge transfer unit, and 109 is a photoelectric conversion. N-type semiconductor region serving as a part, 110
Denotes a P-type semiconductor region serving as a signal readout unit, 111 denotes a P ⁺ -type semiconductor region serving as an element isolation unit, 112a, b, c, d
Denotes charge transfer electrodes of the vertical charge transfer unit, and 113a and 113b denote charge transfer electrodes of the horizontal charge transfer unit.

The charge transfer electrodes 112a of the vertical charge transfer section
Drive pulses of different phases are applied to b, c, and d, respectively, and drive pulses of different phases are applied to the charge transfer electrodes 113a and 113b of the horizontal charge transfer unit. In addition,
Each charge transfer electrode of the vertical charge transfer section and the horizontal charge transfer section is formed with a gap of about 0.3 μm.

Next, the manufacturing process of the solid-state imaging device shown in FIG. 1 will be described with reference to FIG.
The description will be made using the II-II ′ cross section of the horizontal charge transfer unit.

First, when the impurity concentration is 1.0 × 10 ¹⁶ cm ⁻³
An N-type semiconductor region 102 having a reverse conductivity type impurity concentration of about 1.0 × 10 ¹⁷ cm ⁻³ is formed in a P-type semiconductor substrate 101 having a size of about 1.0 × 10 ¹⁷ cm ⁻³ . Then, about 30 nm is obtained by performing thermal oxidation.
A first oxide film 103 is formed to a degree (FIG. 2A).

Next, the first oxide film 10 formed on the horizontal charge transfer section 20 is formed by photolithography and etching.
3 and first oxide film 1 formed on vertical charge transfer section 30
03 is partially removed. After that, a second oxide film 104 of about 60 nm is formed by performing thermal oxidation again. At this time, the first oxide film 103 remaining in the horizontal charge transfer section 30 further grows to a thickness of about 70 nm.

As a result, the entire surface of the vertical charge transfer section 20 is covered with the second oxide film 104 having a thickness of about 60 nm, and the first oxide film 103 of the horizontal charge transfer section 30 is etched by the above-described etching. The removed portion is covered with a second oxide film 104 having a thickness of about 60 nm, and the portion where the first oxide film 103 is not removed is covered with a first oxide film 103 having a thickness of about 70 nm. Will be done.

Next, the first oxide film 103 and the second
By forming a polycrystalline silicon film on the oxide film 104 and patterning the same, a charge transfer electrode 112 is formed in the vertical charge transfer section 20 and a charge transfer electrode 113 is formed in the horizontal charge transfer section 30. . The distance between the charge transfer electrodes 112 and the distance between the charge transfer electrodes 113 are about 0.3 μm. Further, as shown in the II ′ section, the distance between the final charge transfer electrode 112 of the vertical charge transfer section 20 and the charge transfer electrode 113 of the horizontal charge transfer section 30 is also about 0.3 μm (FIG. 2B). )).

Subsequently, a mask material is formed on the entire surface, and a photo-etching method is used to correspond between the final charge transfer electrode 112 of the vertical charge transfer section 20 and the charge transfer electrode 113 of the horizontal charge transfer section 30. The portions are selectively removed, and the mask material 116a is removed.
And Then, using the mask material 116a as a mask, an impurity (for example, boron) of a conductivity type opposite to that of the N-type semiconductor region 102 is used.
Is introduced by an ion implantation method. Thus, a first N ⁻ type semiconductor region 106 having an impurity concentration of about 9.7 × 10 ¹⁶ cm ⁻³ is formed (FIG. 2C).

Further, a mask material is formed again on the entire surface, and a portion corresponding to between the respective charge transfer electrodes 112 of the vertical charge transfer section 20 is selectively removed by using a photolithography method. I do. After that, an impurity (for example, boron) of a conductivity type opposite to that of the N-type semiconductor region 102 is introduced by ion implantation using the mask material 116b as a mask. Thus, a second N-type semiconductor region 107 having an impurity concentration of about 9.5 × 10 ¹⁶ cm ⁻³ is formed (FIG. 2D).

Further, a mask material is formed again on the entire surface, and portions corresponding to the portions between the charge transfer electrodes 113 of the horizontal charge transfer section 30 are selectively removed by using a photolithography method. I do. Thereafter, an impurity (for example, boron) of a conductivity type opposite to that of the N-type semiconductor region 102 is introduced by ion implantation using the mask material 116c as a mask. As a result, a third N-type semiconductor region 108 having an impurity concentration of about 9.0 × 10 ¹⁶ cm ⁻³ is formed (FIG. 2E).

Thereafter, the interlayer insulating film 11 is formed by a known technique.
4 (FIG. 2F), and the charge transfer electrodes 112a, b, c, and d of the vertical charge transfer section and the charge transfer electrodes 113a and 113b of the horizontal charge transfer section are connected via the metal wiring 115 via this. This completes the charge transfer device of the present invention (FIG. 2 (g)).

Generally, when such a solid-state imaging device is driven, each charge transfer electrode 11 of the vertical charge transfer unit 20 is driven.
To 2a, b, c, and d, drive pulses having amplitudes of about 0 to -8 V and having phases shifted by 90 degrees are applied, respectively, and the charge transfer electrodes 113a, 113b of the horizontal charge transfer unit 30 are applied.
, Drive pulses having an amplitude of about 0 to 5 V and a phase shift of 180 degrees are applied.

As described above, the drive pulse applied to the charge transfer electrode 112 of the vertical charge transfer section 20 and the drive pulse applied to the charge transfer electrode 113 of the horizontal charge transfer section 30 are:
Its amplitude and potential are also different. Furthermore, the vertical charge transfer unit 20 and the horizontal charge transfer unit 30 have different channel widths, and the narrower the channel width, the more pronounced the narrow channel effect. Therefore, the potential formed between the charge transfer electrodes 112 of the vertical charge transfer unit 20 and the potential formed between the charge transfer electrodes 113 of the horizontal charge transfer unit 30 have different depths. I have. Furthermore, the final charge transfer electrode 1 of the vertical charge transfer unit 20
The depth of the potential formed between the charge transfer electrode 12 and the charge transfer electrode 113 of the horizontal charge transfer unit 30 is also different from the above potential.

However, according to the solid-state imaging device of this embodiment, the impurity concentration is 9.7 × 1 between the charge transfer electrodes serving as connection regions between the vertical charge transfer unit 20 and the horizontal charge transfer unit 30.
A first N ⁻ type semiconductor region of about 0 ¹⁶ cm ⁻³ is formed,
A second N ⁻ type semiconductor region having an impurity concentration of about 9.5 × 10 ¹⁶ cm ⁻³ is formed between the charge transfer electrodes 112 of the vertical charge transfer unit 20, and each charge transfer of the horizontal charge transfer unit 30 is formed. A third N ⁻ -type semiconductor region having an impurity concentration of about 9.0 × 10 ¹⁶ cm ⁻³ is formed between the electrodes 113. For this reason, as described above, even when the channel widths of the vertical charge transfer unit 20 and the horizontal charge transfer unit 30 and the amplitudes and potentials of the drive pulses applied to these charge transfer electrodes are different, the vertical charge transfer unit 20 A uniform potential potential between the charge transfer electrodes 112, between the charge transfer electrodes 113 of the horizontal charge transfer unit 30, and in all the connection regions between the vertical charge transfer unit 20 and the horizontal charge transfer unit 30 so as not to hinder the charge transfer. Is formed. This improves the charge transfer efficiency.

Next, referring to FIG. 3, another manufacturing process of the solid-state imaging device shown in FIG. 1 will be described by using the II ′ section of the vertical charge transfer section and the II-II ′ section of the horizontal charge transfer section. Of forming charge transfer electrodes 112 and 113 (FIG. 3)
Steps up to (a) and (b)) are the same as the steps shown in FIGS. 2A and 2B, and a description thereof will be omitted.

The steps shown in FIGS. 3A and 3B
After forming the load transfer electrodes 112 and 113, the mask material is removed.
Without being formed, having a conductivity type opposite to that of the N-type semiconductor region 102.
Impurities (for example, boron) are introduced by an ion implantation method.
Thereby, between each charge transfer electrode 112 and 113,
The impurity concentration is 9.7 × 10¹⁶cm^-3First N of degree^- Type
A semiconductor region 106 is formed (FIG. 3C).

Next, a mask material is formed on the entire surface, and each charge transfer electrode 11 of the vertical charge transfer section 20 is formed by photolithography.
A portion corresponding to a portion between the two and a portion corresponding to a portion between the charge transfer electrodes 113 of the horizontal charge transfer portion 30 are selectively removed to obtain a mask material 116a. After that, using the mask material 116a as a mask, an impurity (for example, boron) of a conductivity type opposite to that of the N-type semiconductor region 102 is introduced by an ion implantation method. Thereby, the second N having an impurity concentration of about 9.5 × 10 ¹⁶ cm ⁻³ is obtained.
^A- type semiconductor region 107 is formed (FIG. 3D).

Further, a mask material is formed again on the entire surface, and portions corresponding to the portions between the charge transfer electrodes 113 of the horizontal charge transfer section 30 are selectively removed by using a photolithography method. I do. After that, an impurity (for example, boron) of a conductivity type opposite to that of the N-type semiconductor region 102 is introduced by ion implantation using the mask material 116b as a mask. Thus, a third N ⁻ -type semiconductor region 108 having an impurity concentration of about 9.0 × 10 ¹⁶ cm ⁻³ is formed (FIG. 3E).

Thereafter, the interlayer insulating film 11 is formed by a known technique.
4 (FIG. 3F), through which the charge transfer electrodes 112a, b, c, and d of the vertical charge transfer section and the charge transfer electrodes 113a and 113b of the horizontal charge transfer section are connected by the metal wiring 115. Thereby, the charge transfer device of the present invention is completed (FIG. 3G).

As described above, by performing ion implantation sequentially from a region having a low impurity concentration to be introduced, the number of steps by the photolithography method is reduced by one.

Next, referring to FIG. 4, another manufacturing process of the solid-state imaging device shown in FIG.
The description will be made with reference to the I ′ section and the II-II ′ section of the horizontal charge transfer unit.

The steps up to the step of forming the charge transfer electrodes 112 and 113 (FIGS. 4A and 4B) are the same as the steps shown in FIGS. 2A and 2B, and a description thereof will be omitted. I do.

After the charge transfer electrodes 112 and 113 are formed by the steps shown in FIGS. 4A and 4B, a mask material is formed on the entire surface, and the vertical charge transfer section 2 is formed by photolithography.
0 and the final charge transfer electrode of the vertical charge transfer section 20 and the horizontal charge transfer section 30
A portion corresponding to the portion between the charge transfer electrodes 112 is selectively removed to form a mask material 116a. Then, mask material 1
Using the mask 16a as a mask, an impurity (for example, boron) of a conductivity type opposite to that of the N-type semiconductor region 102 is introduced by ion implantation. Thus, the first N ⁻ -type semiconductor region 106 having an impurity concentration of about 9.7 × 10 ¹⁶ cm ⁻³ is formed.
(C)).

Further, a mask material is again formed on the entire surface, and a portion corresponding to between the charge transfer electrodes 113 of the horizontal charge transfer section 30 is selectively removed by using a photolithography method. I do. After that, an impurity (for example, boron) of a conductivity type opposite to that of the N-type semiconductor region 102 is introduced by ion implantation using the mask material 116b as a mask. Thereby, the second N ⁻ type semiconductor region 108 having an impurity concentration of about 9.0 × 10 ¹⁶ cm ⁻³ is formed (FIG. 4D).

Thereafter, the interlayer insulating film 11 is formed by a known technique.
4 (FIG. 4E), through which the charge transfer electrodes 112a, 112b, 112c, and 112d of the vertical charge transfer unit and the charge transfer electrodes 113a and 113b of the horizontal charge transfer unit are connected by the metal wiring 115. Thereby, the charge transfer device of the present invention is completed (FIG. 4F).

As described above, the impurity concentration between each charge transfer electrode 112 of the vertical charge transfer section 20 and the vertical charge transfer section 20
Even if the impurity concentration between the final charge transfer electrode and the charge transfer electrode 112 of the horizontal charge transfer unit 30 is the same, if there is no practical problem, these are simultaneously formed by a common ion implantation step. , The process can be simplified. That is, according to this method, the ion implantation for forming each of the regions 106 and 108 is performed once each as in the method shown in FIG. 2, and the condition setting in each ion implantation step is shown in FIG. As with the method shown in FIG. 3, the method is easy and the photolithography process for ion implantation is reduced by one time as compared with the method shown in FIG.

Next, referring to FIG. 5, another manufacturing process of the solid-state imaging device shown in FIG.
The description will be made with reference to the I ′ section and the II-II ′ section of the horizontal charge transfer unit.

The steps up to the step of forming the charge transfer electrodes 112 and 113 (FIGS. 5A and 5B) are the same as the steps shown in FIGS. 2A and 2B, and a description thereof will be omitted. I do.

After the charge transfer electrodes 112 and 113 are formed by the steps shown in FIGS. 5A and 5B, a mask material is formed on the entire surface, and the vertical charge transfer portions 2 are formed by photolithography.
The portion corresponding to each of the 0 charge transfer electrodes 112 is selectively removed to form a mask material 116a. Then, mask material 1
Using the mask 16a as a mask, an impurity (for example, boron) of a conductivity type opposite to that of the N-type semiconductor region 102 is introduced by ion implantation. Thereby, the first N ⁻ -type semiconductor region 106 having an impurity concentration of about 9.5 × 10 ¹⁶ cm ⁻³ is formed.
(C)).

Further, a mask material is formed again on the entire surface, and the portion corresponding to each space between the charge transfer electrodes 113 of the horizontal charge transfer section 30 and the final charge transfer electrode of the vertical charge transfer section 20 are formed by photolithography. And the charge transfer electrode 1 of the horizontal charge transfer unit 30
12 is selectively removed to obtain a mask material 116b. After that, an impurity (for example, boron) of a conductivity type opposite to that of the N-type semiconductor region 102 is introduced by ion implantation using the mask material 116b as a mask. Thus, a second N ⁻ -type semiconductor region 108 having an impurity concentration of about 9.0 × 10 ¹⁶ cm ⁻³ is formed (FIG. 5D).

Thereafter, the interlayer insulating film 11 is formed by a known technique.
4 (FIG. 5E), through which the charge transfer electrodes 112a, b, c, and d of the vertical charge transfer unit and the charge transfer electrodes 113a and 113b of the horizontal charge transfer unit are connected by the metal wiring 115. Thereby, the charge transfer device of the present invention is completed (FIG. 5F).

As described above, the impurity concentration between the charge transfer electrodes 113 of the horizontal charge transfer section 30 and the vertical charge transfer section 20
Even if the impurity concentration between the final charge transfer electrode and the charge transfer electrode 112 of the horizontal charge transfer unit 30 is the same, if there is no practical problem, these are simultaneously formed by a common ion implantation step. , The process can be simplified. That is, according to this method, the ion implantation for forming each of the regions 106 and 108 is performed once each as in the method shown in FIG. 2, and the condition setting in each ion implantation step is shown in FIG. Like the method, it is easy and the photolithography process for ion implantation is reduced by one time as compared with the method shown in FIG. 2 as in the method shown in FIGS.

Although not shown, the step of implanting ions between the charge transfer electrodes 112 of the vertical charge transfer section 20 is omitted particularly when the interval between the charge transfer electrodes 112 of the vertical charge transfer section 20 is narrower. It is also possible. In this case, for example, of the steps shown in FIG. 2, the step of FIG. 2D may be omitted. Alternatively, of the steps shown in FIG. 3, the step of FIG.
In this step, the vertical charge transfer section 20 may be covered with the mask material 116. According to this, the photolithography process for ion implantation is reduced by one time as compared with the method shown in FIG.

Further, when the step of implanting ions between the charge transfer electrodes 112 of the vertical charge transfer section 20 is omitted, as described with reference to FIG.
Even if the impurity concentration between the respective charge transfer electrodes 113 and the impurity concentration between the final charge transfer electrode of the vertical charge transfer unit 20 and the charge transfer electrode 112 of the horizontal charge transfer unit 30 are the same, there is no practical problem. In that case, the manufacturing process is further simplified. That is, of the steps shown in FIG. 5, the step of FIG. 5C may be omitted. According to this, the ion implantation step is required only once in FIG.

Further, not only the step of implanting ions between the charge transfer electrodes 112 of the vertical charge transfer section 20 is omitted, but also the final charge transfer electrode of the vertical charge transfer section 20 and the charge transfer electrode 112 of the horizontal charge transfer section 30. It is also possible to omit the ion implantation step between the two and to implant ions only between the charge transfer electrodes 113 of the horizontal charge transfer unit 30. In this case, the step of FIG. 4C may be omitted from the steps shown in FIG. According to this, the ion implantation step is performed as shown in FIG.
(D) only once.

Next, a solid-state imaging device according to another embodiment of the present invention will be described. Referring to FIG. 6, the solid-state imaging device according to the present embodiment includes a photoelectric conversion unit 10, a vertical charge transfer unit 20, and a horizontal charge transfer unit 30. The vertical charge transfer unit 20 and the horizontal charge transfer unit 30 have a single-layer electrode structure. The vertical charge transfer unit 20 is driven by a drive pulse including a four-phase clock, and transfers the charge generated by the photoelectric conversion unit 10 to the horizontal charge transfer unit 30. Horizontal charge transfer unit 3
0 is driven by a driving pulse composed of a two-phase clock, and transfers the electric charge transferred from the vertical charge transfer unit 20 to an output terminal (not shown).

The solid-state image pickup device shown in FIG. 6 differs from the solid-state image pickup device shown in FIG. 1 in that the distance between the charge transfer electrodes 112 of the vertical charge transfer section 20 and the charge transfer electrodes 113 of the horizontal charge transfer section 30 are different. The difference is that the interval between them is different. That is, the interval between the charge transfer electrodes 112 of the vertical charge transfer unit 20 is about 0.3 μm, and the interval between the charge transfer electrodes 113 of the horizontal charge transfer unit 30 is about 0.5 μm.
The distance between the final charge transfer electrode 112 of the vertical charge transfer section 20 and the charge transfer electrode 113 of the horizontal charge transfer section 30 is about 0.3 μm.

As described above, by setting the interval between the charge transfer electrodes 113 of the horizontal charge transfer unit 30 to be wider than the interval between the charge transfer electrodes 112 of the vertical charge transfer unit 20, the horizontal charge transfer unit 30 The capacitance between the respective charge transfer electrodes 113 is reduced, thereby reducing the power consumed by the horizontal charge transfer unit having a high driving frequency.

Next, referring to FIG. 7, the manufacturing process of the solid-state imaging device shown in FIG.
The description will be made using the II-II ′ cross section of the horizontal charge transfer unit.

First, the impurity concentration is 1.0 × 10 ¹⁶ cm ^−3.
An N-type semiconductor region 102 having a reverse conductivity type impurity concentration of about 1.0 × 10 ¹⁷ cm ⁻³ is formed in a P-type semiconductor substrate 101 having a size of about 1.0 × 10 ¹⁷ cm ⁻³ . Then, about 30 nm is obtained by performing thermal oxidation.
A first oxide film 103 having a thickness of approximately the same level is formed (FIG. 7A).

Next, the first oxide film 10 formed on the horizontal charge transfer section 20 is formed by photolithography and etching.
3 and first oxide film 1 formed on vertical charge transfer section 30
03 is partially removed. After that, a second oxide film 104 of about 60 nm is formed by performing thermal oxidation again. At this time, the first oxide film 103 remaining in the horizontal charge transfer section 30 further grows to a thickness of about 70 nm.

As a result, the entire surface of the vertical charge transfer portion 20 is covered with the second oxide film 104 having a thickness of about 60 nm, and the first oxide film 103 of the horizontal charge transfer portion 30 is etched by the above-described etching. The removed portion is covered with a second oxide film 104 having a thickness of about 60 nm, and the portion where the first oxide film 103 is not removed is covered with a first oxide film 103 having a thickness of about 70 nm. Will be done.

Next, the first oxide film 103 and the second
By forming a polycrystalline silicon film on the oxide film 104 and patterning the same, a charge transfer electrode 112 is formed in the vertical charge transfer section 20 and a charge transfer electrode 113 is formed in the horizontal charge transfer section 30. . The interval between the charge transfer electrodes 112 of the vertical charge transfer unit 20 is about 0.3 μm,
The space between the charge transfer electrodes 113 of the horizontal charge transfer unit 30 is about 0.5 μm. Further, as shown in the II ′ section, the distance between the final charge transfer electrode 112 of the vertical charge transfer unit 20 and the charge transfer electrode 113 of the horizontal charge transfer unit 30 is about 0.3 μm (FIG. 7B )).

Subsequently, a mask material is formed on the entire surface, and a portion corresponding to the space between the final charge transfer electrode 112 of the vertical charge transfer section 20 and the charge transfer electrode 113 of the horizontal charge transfer section 30 is formed by photolithography. The portions are selectively removed, and the mask material 116a is removed.
And Then, using the mask material 116a as a mask, an impurity (for example, boron) of a conductivity type opposite to that of the N-type semiconductor region 102 is used.
Is introduced by an ion implantation method. Thus, the first N ⁻ -type semiconductor region 106 having an impurity concentration of about 9.7 × 10 ¹⁶ cm ⁻³ is formed (FIG. 7C).

Further, a mask material is again formed on the entire surface, and portions corresponding to the portions between the respective charge transfer electrodes 112 of the vertical charge transfer section 20 are selectively removed using a photolithography method. I do. After that, an impurity (for example, boron) of a conductivity type opposite to that of the N-type semiconductor region 102 is introduced by ion implantation using the mask material 116b as a mask. Thereby, the second N ⁻ -type semiconductor region 107 having an impurity concentration of about 9.5 × 10 ¹⁶ cm ⁻³ is formed (FIG. 7D).

Further, a mask material is again formed on the entire surface, and portions corresponding to the portions between the charge transfer electrodes 113 of the horizontal charge transfer section 30 are selectively removed by using a photolithography method. I do. Thereafter, an impurity (for example, boron) of a conductivity type opposite to that of the N-type semiconductor region 102 is introduced by ion implantation using the mask material 116c as a mask. As a result, a third N ⁻ -type semiconductor region 108 having an impurity concentration of about 8.0 × 10 ¹⁶ cm ⁻³ is formed (FIG. 7E).

Thereafter, the interlayer insulating film 11 is formed by a known technique.
4 (FIG. 7F), and the charge transfer electrodes 112a, b, c, and d of the vertical charge transfer unit and the charge transfer electrodes 113a and 113b of the horizontal charge transfer unit are connected via the metal wiring 115 via this. Thereby, the charge transfer device of the present invention is completed (FIG. 7G).

As described above, according to the solid-state imaging device of the present embodiment, the impurity concentration between the charge transfer electrodes serving as the connection region between the vertical charge transfer unit 20 and the horizontal charge transfer unit 30 is 9.7 ×.
A first N ⁻ type semiconductor region 106 of about 10 ¹⁶ cm ⁻³ is formed, and a second impurity concentration of about 9.5 × 10 ¹⁶ cm ⁻³ is provided between each charge transfer electrode 112 of the vertical charge transfer section 20. N
^- -type semiconductor Ryojo 107 is formed, the horizontal charge transfer portion 30
Between each charge transfer electrode 113 is 8.0 × 1
A third N ⁻ type semiconductor region 108 of about 0 ¹⁶ cm ⁻³ is formed.

That is, in this embodiment, in order to reduce power consumption in the horizontal charge transfer section having a high driving frequency, the interval between the charge transfer electrodes 113 of the horizontal charge transfer section 30 is set to be equal to each charge of the vertical charge transfer section 20. Since the distance between the transfer electrodes 112 is set to be wider, a uniform potential is formed in each region by setting the impurity concentration between the charge transfer electrodes 113 of the horizontal charge transfer unit 30 even lower. This improves the charge transfer efficiency.

In the solid-state imaging device according to the present embodiment, the impurity concentration of each region may be set by using the method shown in FIGS.

Next, a solid-state imaging device according to still another embodiment of the present invention will be described with reference to FIG.

In the solid-state imaging device according to the present embodiment shown in FIG. 7, the impurity concentration of the opposite conductivity type formed in the N-type semiconductor substrate 201 having the impurity concentration of about 1.0 × 10 ¹⁶ cm ⁻³ is 1. A P-type well layer 202 of about 0 × 10 ¹⁶ cm ⁻³ is formed, an N-type semiconductor region 102 of the opposite conductivity type is formed in the P-type well layer 202, and a charge is formed on the P-type well layer 202. The transfer electrodes 112 and 113 are formed.
8A to 8G, except that a step of forming a P-type well layer 202 in an N-type semiconductor substrate 201 is the same as the method shown in FIG. 2 or FIG. The same is true. It goes without saying that the methods shown in FIGS. 3 to 5 may be used.

As described above, the present invention is also applicable to a solid-state imaging device using a well.

In each of the above-described embodiments, the present invention is applied to a buried type charge transfer device. However, the present invention can be similarly applied to a surface type charge transfer device.

FIG. 9 is a diagram for explaining an embodiment in which the present invention is applied to a surface-type charge transfer device. Also in this embodiment, the interval between the charge transfer electrodes 112 of the vertical charge transfer unit 20 and the interval between the charge transfer electrodes 113 of the horizontal charge transfer unit 30 are different. That is, the vertical charge transfer unit 20
The interval between the respective charge transfer electrodes 112 is about 0.3 μm, and the interval between the respective charge transfer electrodes 113 of the horizontal charge transfer section 30 is about 0.5 μm. The distance between the final charge transfer electrode 112 of the vertical charge transfer section 20 and the charge transfer electrode 113 of the horizontal charge transfer section 30 is about 0.3 μm. Like this
By setting the interval between the charge transfer electrodes 113 of the horizontal charge transfer unit 30 wider than the interval between the charge transfer electrodes 112 of the vertical charge transfer unit 20, the power consumed by the horizontal charge transfer unit with a high driving frequency is increased. Has been reduced.

Next, the manufacturing process of the solid-state imaging device shown in FIG. 9 will be described with reference to FIGS. 10A to 10C by using a II-II section of the vertical charge transfer section and a II-II 'section of the horizontal charge transfer section. I do.

First, the impurity concentration is 1.0 × 10 ¹⁶ cm ^−3.
The first oxide film 103 having a thickness of about 30 nm is formed by thermally oxidizing the P-type semiconductor substrate 101 having a thickness of about 30 nm.
(A)).

Next, the first oxide film 10 formed on the horizontal charge transfer section 20 is formed by photolithography and etching.
3 and first oxide film 1 formed on vertical charge transfer section 30
03 is partially removed. After that, a second oxide film 104 of about 60 nm is formed by performing thermal oxidation again. At this time, the first oxide film 103 remaining in the horizontal charge transfer section 30 further grows to a thickness of about 70 nm.

As a result, the entire surface of the vertical charge transfer section 20 is covered with the second oxide film 104 having a thickness of about 60 nm, and the first oxide film 103 of the horizontal charge transfer section 30 is etched by the above-described etching. The removed portion is covered with a second oxide film 104 having a thickness of about 60 nm, and the portion where the first oxide film 103 is not removed is covered with a first oxide film 103 having a thickness of about 70 nm. Will be done.

Next, the first oxide film 103 and the second
By forming a polycrystalline silicon film on the oxide film 104 and patterning the same, a charge transfer electrode 112 is formed in the vertical charge transfer section 20 and a charge transfer electrode 113 is formed in the horizontal charge transfer section 30. . The interval between the charge transfer electrodes 112 of the vertical charge transfer unit 20 is about 0.3 μm,
The space between the charge transfer electrodes 113 of the horizontal charge transfer unit 30 is about 0.5 μm. Further, as shown in the II ′ section, the distance between the final charge transfer electrode 112 of the vertical charge transfer unit 20 and the charge transfer electrode 113 of the horizontal charge transfer unit 30 is about 0.3 μm (FIG. 10B )).

Subsequently, a mask material is formed on the entire surface, and a space between the final charge transfer electrode 112 of the vertical charge transfer section 20 and the charge transfer electrode 113 of the horizontal charge transfer section 30 is formed by photolithography. The portions are selectively removed, and the mask material 116a is removed.
And Thereafter, using the mask material 116a as a mask, an impurity (for example, phosphorus) of a conductivity type opposite to that of the P-type semiconductor region 101 is introduced by an ion implantation method (FIG. 10C).

Further, a mask material is again formed on the entire surface, and a portion corresponding to between the charge transfer electrodes 112 of the vertical charge transfer section 20 is selectively removed by using a photolithography method. I do. Thereafter, using the mask material 116b as a mask, an impurity (for example, phosphorus) of a conductivity type opposite to that of the P-type semiconductor region 101 is introduced by an ion implantation method (FIG. 10D).

Further, a mask material is formed again on the entire surface, and portions corresponding to the portions between the charge transfer electrodes 113 of the horizontal charge transfer portion 30 are selectively removed by using a photolithography method, so that the mask material 116c is removed. I do. Thereafter, using the mask material 116c as a mask, an impurity (eg, phosphorus) of a conductivity type opposite to that of the P-type semiconductor region 101 is introduced by an ion implantation method (FIG. 10E).

Thereafter, the interlayer insulating film 11 is formed by a known technique.
4 (FIG. 10 (f)), through which the charge transfer electrodes 112a, b, c, and d of the vertical charge transfer section and the charge transfer electrodes 113a and 113b of the horizontal charge transfer section are connected to the metal wiring 115.
To complete the charge transfer device of the present invention (FIG. 10 (g)).

As described above, in the solid-state imaging device according to the present embodiment, similarly to the solid-state imaging devices according to the above-described embodiments, the charge transfer electrodes of the vertical charge transfer unit 20 and the charge transfer electrodes of the horizontal charge transfer unit 30 are provided. A uniform potential can be formed between the adjacent charge transfer portions 113 and in the connection region between the vertical charge transfer section 20 and the horizontal charge transfer section 30, thereby improving the charge transfer efficiency.

The present invention is not limited to the above-described interline solid-state imaging device including the above-described single-layer electrode four-phase driven vertical charge transfer unit and the single-layer electrode two-phase driven horizontal charge transfer unit. Or a three-phase drive or a frame transfer type solid-state imaging device.

[0096]

As described above, according to the solid-state imaging device of the present invention, the connection region between the vertical charge transfer section and the horizontal charge transfer section, between the charge transfer electrodes of the vertical charge transfer section, and the horizontal charge transfer section. Since the semiconductor regions having different impurity concentrations are provided between the respective charge transfer electrodes, it is possible to form a uniform potential between the electrodes so as not to hinder the charge transfer. The charge transfer efficiency can be improved.

Further, of these semiconductor regions, any two
If the impurity concentrations of the two semiconductor regions are made equal, the manufacturing process can be simplified.

[Brief description of the drawings]

FIG. 1 is a plan view of a solid-state imaging device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of main steps showing a method for manufacturing the solid-state imaging device according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a main step showing another method of manufacturing the solid-state imaging device according to the first embodiment of the present invention;

FIG. 4 is a cross-sectional view of main steps showing still another method of manufacturing the solid-state imaging device according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view of main steps showing still another method of manufacturing the solid-state imaging device according to the first embodiment of the present invention.

FIG. 6 is a plan view of a solid-state imaging device according to a second embodiment of the present invention.

FIG. 7 is a cross-sectional view of main steps showing a method for manufacturing a solid-state imaging device according to a second embodiment of the present invention.

FIG. 8 is a sectional view of main steps showing a method for manufacturing a solid-state imaging device according to a third embodiment of the present invention.

FIG. 9 is a plan view of a solid-state imaging device according to a fourth embodiment of the present invention.

FIG. 10 is a sectional view of main steps showing a method for manufacturing a solid-state imaging device according to a fourth embodiment of the present invention.

FIG. 11 is a plan view of a conventional solid-state imaging device.

FIG. 12 is a cross-sectional view of main steps showing a conventional method for manufacturing a solid-state imaging device.

FIG. 13 is a diagram showing a shape of a potential formed between electrodes.

FIG. 14 is a diagram for explaining that the shape of the potential formed between the electrodes differs depending on the amount of ion implantation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Photoelectric conversion part 20 Vertical charge transfer part 30 Horizontal charge transfer part 101 P-type semiconductor substrate 102 N-type semiconductor region of a charge transfer part 103 1st insulating film 104 2nd insulating film 105 N ^- type semiconductor region 106 1st N ^- type semiconductor region 107 Second N ^- type semiconductor region 108 Third N ^- type semiconductor region 109 N ^- type semiconductor region of photoelectric conversion unit 110 P-type semiconductor region 111 P ⁺ -type semiconductor region 112 Charge of vertical charge transfer unit Transfer electrode 113 Charge transfer electrode of horizontal charge transfer section 114 Interlayer insulating film 115 Metal wiring 116 Photoresist 201 N-type semiconductor substrate 202 P-type well layer 306 First P ^- type semiconductor region 307 Second P ^- type semiconductor region 308 third P ⁻ type semiconductor region 1201 electrode 1202 potential

Claims (19)

[Claims] 1. A photoelectric conversion unit, a vertical charge transfer unit for vertically transferring the charge generated in the photoelectric conversion unit, and a horizontal charge receiving the charge transferred from the vertical charge transfer unit and transferring the charge in a horizontal direction. A solid-state imaging device comprising: a charge transfer unit; a plurality of vertical charge transfer electrodes provided in the vertical charge transfer unit; a first impurity region provided between the vertical charge transfer electrodes; A plurality of horizontal charge transfer electrodes provided in the charge transfer portion; a second impurity region provided between the horizontal charge transfer electrodes; and a second impurity region provided between the vertical charge transfer electrode and the horizontal charge transfer electrode. And the third impurity region has an impurity concentration of:
A solid-state imaging device, wherein at least one of the first and second impurity regions has a different impurity concentration. 2. An impurity concentration of the third impurity region,
2. The solid-state imaging device according to claim 1, wherein the impurity concentration is higher than at least one of the first and second impurity regions. 3. An impurity concentration of the third impurity region,
2. The solid according to claim 1, wherein the impurity concentration of one of the first and second impurity regions is different from that of the other of the first and second impurity regions. 3. Imaging device. 4. The impurity concentration of the third impurity region is:
4. The solid-state imaging device according to claim 3, wherein said one of said first and second impurity regions has a higher impurity concentration than said one of said first and second impurity regions. 5. The solid-state imaging device according to claim 1, wherein the first, second, and third impurity regions have different impurity concentrations. 6. An impurity concentration of the first impurity region is higher than an impurity concentration of the second impurity region.
The solid-state imaging device according to claim 5, wherein the impurity concentration of the impurity region is higher than the impurity concentration of the third impurity region. 7. In a solid-state imaging device including a photoelectric conversion unit, a vertical charge transfer unit, and a horizontal charge transfer unit, the vertical charge transfer unit includes a plurality of one conductivity type first impurity regions and an insulating film. A plurality of vertical charge transfer electrodes provided on the plurality of first impurity regions, respectively, and a plurality of one conductivity type second impurity regions provided between the plurality of first impurity regions, respectively. The horizontal charge transfer section includes a plurality of third impurity regions of the one conductivity type; a plurality of horizontal charge transfer electrodes provided on the plurality of third impurity regions via an insulating film; A plurality of one-conductivity-type fourth impurity regions provided between the third impurity regions, respectively, and an impurity concentration of the second impurity region and the fourth impurity region;
A solid-state imaging device, wherein the impurity concentration of the impurity region is different from that of the impurity region. 8. The semiconductor device further comprising a fifth impurity region of the one conductivity type provided between the first impurity region and the third impurity region, wherein an impurity concentration of the fifth impurity region is at least the second impurity region. 8. The solid-state imaging device according to claim 7, wherein the impurity concentration is different from one of the impurity concentrations of the first and fourth impurity regions. 9. An impurity concentration of each of the first and third impurity regions is higher than an impurity concentration of the fifth impurity region, and an impurity concentration of the fifth impurity region is at least one of the second and fourth impurity regions. The solid-state imaging device according to claim 8, wherein the impurity concentration is higher than one of the impurity concentrations. 10. The solid-state imaging device according to claim 8, wherein the first, second, fourth, and fifth impurity regions have different impurity concentrations. 11. The impurity concentration of the first impurity region and the impurity concentration of the third impurity region are substantially the same, and the impurity concentration of the second impurity region and the impurity concentration of the fifth impurity region are different. The impurity concentration of the first and third impurity regions is higher than the impurity concentration of the second and fifth impurity regions, and the impurity concentration of the second and fifth impurity regions is substantially the same as that of the fourth impurity region. 9. The solid-state imaging device according to claim 8, wherein the impurity concentration is higher than a region. 12. An impurity concentration of the first impurity region and an impurity concentration of the third impurity region are substantially the same, and an impurity concentration of the fourth impurity region and an impurity concentration of the fifth impurity region are different from each other. The first and third impurity regions have substantially the same impurity concentration as the second impurity region, and the second impurity region has an impurity concentration of the fourth and fifth impurity regions. 9. The solid-state imaging device according to claim 8, wherein the density is higher than the density. 13. The first, second, and third impurity regions have the same impurity concentration, and the fourth and fifth impurity regions have the same impurity concentration. And the third impurity region has an impurity concentration of the fourth impurity region.
9. The solid-state imaging device according to claim 8, wherein the impurity concentration is higher than an impurity concentration of the fifth impurity region. 14. The first, second, third and fifth impurity regions have the same impurity concentration, and the first, second, third and fifth impurity regions have the same impurity concentration. 9. The solid-state imaging device according to claim 8, wherein the impurity concentration is higher than the impurity concentration of the four impurity regions. 15. A step of forming an impurity region of the opposite conductivity type in a semiconductor substrate of one conductivity type, a step of forming an insulating film on the semiconductor substrate, and forming a plurality of vertical charge transfer electrodes and Forming a plurality of horizontal charge transfer electrodes;
Covering the space between the vertical charge transfer electrodes and the space between the horizontal charge transfer electrodes with a mask, and introducing the one conductivity type impurity into the impurity region between the vertical charge transfer electrode and the horizontal charge transfer electrode. Covering the space between the horizontal charge transfer electrodes and the space between the vertical charge transfer electrodes and the horizontal charge transfer electrodes with a mask, and introducing the one conductivity type impurity into the impurity region between the vertical charge transfer electrodes. Covering the space between the vertical charge transfer electrodes and the space between the vertical charge transfer electrodes and the horizontal charge transfer electrodes with a mask, and introducing the one conductivity type impurity into the impurity region between the horizontal charge transfer electrodes. And an impurity region between the vertical charge transfer electrode and the horizontal charge transfer electrode, an impurity region between the vertical charge transfer electrodes, and an impurity region between the horizontal charge transfer electrodes. Method for manufacturing a solid-state imaging device, characterized in that of each of the impurity concentrations were different from each other. 16. A step of forming an impurity region of the opposite conductivity type in a semiconductor substrate of one conductivity type, a step of forming an insulating film on the semiconductor substrate, and forming a plurality of vertical charge transfer electrodes on the insulating film. Forming a plurality of horizontal charge transfer electrodes;
Introducing the one-conductivity-type impurity into the impurity region using the plurality of vertical charge transfer electrodes and the plurality of horizontal charge transfer electrodes as a mask, and using a mask between the vertical charge transfer electrodes and the horizontal charge transfer electrodes. Introducing the one conductivity type impurity into the impurity regions between the vertical charge transfer electrodes and between the horizontal charge transfer electrodes, and between the vertical charge transfer electrodes and the vertical charge transfer electrodes and the horizontal. Covering the space between the charge transfer electrodes with a mask and introducing the one conductivity type impurity into the impurity region between the horizontal charge transfer electrodes. 17. A step of forming an impurity region of the opposite conductivity type in a semiconductor substrate of one conductivity type, a step of forming an insulating film on the semiconductor substrate, and forming a plurality of vertical charge transfer electrodes and Forming a plurality of horizontal charge transfer electrodes;
Covering the space between the horizontal charge transfer electrodes with a mask and introducing the one conductivity type impurity into the impurity region between the vertical charge transfer electrodes and between the vertical charge transfer electrode and the horizontal charge transfer electrode; Covering between the vertical charge transfer electrodes and between the vertical charge transfer electrodes and the horizontal charge transfer electrodes with a mask, and introducing the one conductivity type impurity into the impurity region between the horizontal charge transfer electrodes. A method for manufacturing a solid-state imaging device. 18. A step of forming an impurity region of the opposite conductivity type in a semiconductor substrate of one conductivity type, a step of forming an insulating film on the semiconductor substrate, and forming a plurality of vertical charge transfer electrodes and Forming a plurality of horizontal charge transfer electrodes;
Covering the space between the horizontal charge transfer electrodes and the space between the vertical charge transfer electrodes and the horizontal charge transfer electrodes with a mask, and introducing the one conductivity type impurity into the impurity region between the vertical charge transfer electrodes; Covering the space between the vertical charge transfer electrodes with a mask and introducing the one conductivity type impurity into the impurity region between the horizontal charge transfer electrodes and between the vertical charge transfer electrode and the horizontal charge transfer electrode. A method for manufacturing a solid-state imaging device. 19. A solid-state imaging device comprising a vertical charge transfer section and a horizontal charge transfer section in which single-layer charge transfer electrodes are formed at predetermined intervals on a first conductivity type semiconductor substrate via an insulating film. A first first conductivity type semiconductor region provided in a connection region between the vertical charge transfer unit and the horizontal charge transfer unit, and a second semiconductor device provided in a gap between each charge transfer electrode of the vertical charge transfer unit. And a third first conductivity type semiconductor region provided in a gap between the charge transfer electrodes of the horizontal charge transfer section, and wherein the first first conductivity type semiconductor region is provided. The second first conductivity type semiconductor region and the third first conductivity type semiconductor region have different impurity concentrations, and a potential formed between the charge transfer electrodes of the vertical charge transfer portion when a drive voltage is applied. Potential and each potential of the horizontal charge transfer section. The first electric potential is formed such that the electric potential formed between the load transfer electrodes and the electric potential formed in the connection region between the vertical charge transfer part and the horizontal charge transfer part have substantially the same depth. A first conductivity type semiconductor region, the second first conductivity type semiconductor region, and the third conductivity type semiconductor region;
A solid-state imaging device, wherein an impurity concentration of the first conductivity type semiconductor region is set.