JP2002009273A - Solid-state image pickup element and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate generation of charge leakage between vertically-adjacent light receiving sensors in reading the charge of light sensor to transfer to a vertical transfer register, and additionally can extend the electrode width be tween light receiving sensors of transfer electrodes on a second layer in a CCD solid-state image pickup element. SOLUTION: This image pickup element has a plurality of light receiving sensors 11 and vertical transfer registers 12 arranged on one side of a light receiving sensor array, and insulation films 21 thicker than the gate insulation films 16 are formed just under ends of transfer electrodes 17A, 17C on first layer, and 17B, 17D on second layer arranged between vertically adjacent light receiving sensors 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a solid-state imaging device and a method for manufacturing the same.

[0002]

2. Description of the Related Art As shown in FIG. 10, a solid-state image pickup device, for example, a CCD solid-state image pickup device of an interline transfer (IT) system, has a plurality of light-receiving sensors 1 serving as pixels arranged in a matrix. A vertical transfer register 2 is formed on one side of the column, and the end of each vertical transfer register 2 is connected to a horizontal transfer register 3.
The output circuit 4 is connected to the end of the circuit via charge-voltage conversion means (not shown).

The vertical transfer register 2 is configured, for example, in a four-phase drive system, and a four-phase vertical drive pulse φV [φV ₁ , φV ₂ , φV ₃ , φV ₄ ] is applied to each transfer electrode.
The horizontal transfer register 3 is configured, for example, in a two-phase drive system, and applies a two-phase horizontal drive pulse φH [φ
H ₁ , φH ₂ ] is applied.

As shown in FIGS. 11 and 12, the light receiving sensor section 1 is formed by forming a photodiode on a semiconductor substrate 5, for example. In the vertical transfer register 2, the transfer electrode 7 is formed in, for example, a two-layer polycrystalline silicon structure.
That is, a first polycrystalline silicon film is formed on one main surface of the semiconductor substrate 5 so as to correspond to each light receiving sensor unit 1 via a gate insulating film 6 made of a silicon oxide film, a silicon nitride film, or the like. And third transfer electrodes 7A and 7C are formed,
Similarly, second and fourth transfer electrodes 7B and 7D of the second-layer polycrystalline silicon film are formed corresponding to the respective light receiving sensor sections 1. These transfer electrodes 7A to 7D are repeatedly arranged in the vertical direction and are arranged. Then, each of the transfer electrodes 7A to 7D
Are applied with four-phase vertical drive pulses φV _{1 to} φV ₄ .

The transfer electrodes 7A to 7D are formed in a band along the horizontal direction so as to be common to the vertical transfer registers 2. Between the pixels adjacent in the vertical direction, that is, between the light receiving sensor units 1, the transfer electrode (7) of the first layer polycrystalline silicon film is used.
A, 7C) and a transfer electrode (7B, 7D) of a second-layer polycrystalline silicon film are laminated with an interlayer insulating film 8 interposed therebetween.

The transfer electrodes 7 [7A to 7D] are usually formed as follows. First, through the gate insulating film 6,
After a first-layer polycrystalline silicon film is formed on the entire surface, the first and third transfer electrodes 7 are patterned by etching.
A and 7C are formed. Next, an interlayer insulating film 8 is formed, a second-layer polycrystalline silicon film is formed on the entire surface, and then patterned by etching to form second and fourth transfer electrodes 7B and 7D.

[0007] Such an interline transfer type CC
In the D solid-state imaging device 9, when image light is incident,
Signal electrodes are accumulated in each light receiving sensor unit 1 by photoelectric conversion. This signal charge is read from the light receiving sensor unit 1 to the vertical transfer register 2 through a read gate unit (not shown), and is transferred in the vertical transfer register 2 in the vertical direction.
Next, the signal charges for each line are transferred from the vertical transfer register 2 to the horizontal transfer register 3, and the signal charges for one line are sequentially transferred in the horizontal direction, charge-voltage converted, and output through the output circuit 4.

[0008]

By the way, the transfer portions of the transfer electrodes 7A and 7C of the first layer and the transfer electrodes 7B and 7D of the second layer drive the driving pulses φV _{1 to} φV ₄ of different phases, respectively.
Driven by For this reason, FIG.
As shown in (2), the transfer electrodes 7B and 7D of the second layer must be formed so as not to be adjacent to the transfer electrodes 7A and 7C of the first layer between the light receiving sensor units 1 adjacent in the vertical direction.

In particular, the light receiving sensor units 1 vertically adjacent to each other
For example, in the transfer electrode 7 between
When the signal charges are read by B and 7D, when the transfer electrodes 7B and 7D of the second layer are formed so as to protrude next to the transfer electrodes 7A and 7C of the first layer, the light receiving sensors adjacent in the vertical direction are formed. There is a possibility that signal charges will be read out to the portion through the second-layer transfer electrodes 7B and 7D.

Accordingly, usually, as shown in Figure 11 described above, the second layer transfer electrodes 7B, 7D width W ₁ of the first-layer transfer electrodes 7A of, and less than 7C, the second layer transfer Electrode 7
The transfer electrode 7 is processed so that B and 7D do not protrude from the first-layer transfer electrodes 7A and 7C.

With such a processing limitation, the width W ₁ of the transfer electrodes 7B and 7D of the second layer must be formed extremely thin, leading to disconnection of the transfer electrodes 7B and 7D. As W ₁ becomes thinner, the electrode resistance rises, which causes a propagation delay, which causes a disadvantage that the charge transfer capacity is reduced.

In view of the above, the present invention eliminates the occurrence of signal charge leakage between vertically adjacent light receiving sensor units and reduces the charge transfer capacity due to the propagation delay of a drive pulse applied to a transfer electrode. And a method of manufacturing the same.

[0013]

In the solid-state image pickup device according to the present invention, the first and second transfer electrodes overlap and extend between the light-receiving sensors adjacent to each other in the vertical direction. A thick insulating film is formed immediately below the end in the vertical direction.

In the solid-state imaging device according to the present invention, a thick insulating film is provided immediately below the vertical ends of the first and second transfer electrodes of the vertical transfer register extending between the light-receiving sensors adjacent in the vertical direction. Is formed, even when signal charges are read from the light receiving sensor unit to the vertical transfer register by the second-layer transfer electrode, the signal charges do not leak to the light receiving sensor unit adjacent in the vertical direction. The electrode width of the second-layer transfer electrode extending between the light-receiving sensors adjacent to each other in the vertical direction can be increased, and the transfer electrode is less likely to be disconnected, and the resistance of the transfer electrode is reduced, so that the propagation delay of the drive pulse is less likely to occur.

A method for manufacturing a solid-state imaging device according to the present invention comprises:
An insulating film thicker than the gate insulating film is formed on the semiconductor substrate via the gate insulating film at a position corresponding to each light receiving sensor portion to be formed later, and is embedded in a valley formed by the thick insulating film. Next, a first-layer transfer electrode is formed.
Next, a conductive film serving as a second-layer transfer electrode having an opening in a portion corresponding to each light-receiving sensor portion is formed via the interlayer insulating film, and the interlayer insulating film and the thick insulating film are patterned through the opening, and are patterned. A light receiving sensor is formed in the semiconductor substrate through the opening. Next, the conductive film is patterned to form a second-layer transfer electrode.

In the method of manufacturing a solid-state imaging device according to the present invention, an insulating film thicker than a gate insulating film is formed at a position corresponding to each light-receiving sensor portion, and the insulating film is embedded in a valley formed by the thick insulating film. Forming a transfer electrode of a layer, and then forming a conductive film serving as a transfer electrode of a second layer having an opening at a position corresponding to each thick insulating film via an interlayer insulating film;
By having the step of removing the thick insulating film through the opening, the width between the openings adjacent in the vertical direction becomes smaller than the width between the light receiving sensor units adjacent in the vertical direction of the finally obtained transfer electrode of the second layer. become. Accordingly, when the width of the second-layer transfer electrode is formed smaller than the width of the first-layer transfer electrode between the light-receiving sensors adjacent to each other in the vertical direction, 1
When a thick insulating film exists immediately below the vertical end of the transfer electrode of the layer and the width of the transfer electrode of the second layer is formed larger than the width of the transfer electrode of the first layer, the transfer of the second layer is performed. A thick insulating film exists immediately below the vertical end of the electrode. That is, the second-layer transfer electrode can be processed irrespective of the first-layer transfer electrode, and a processing margin can be increased as compared with the related art.

After the thick insulating film is selectively removed through the opening of the conductive film and the light receiving sensor is formed on the semiconductor substrate through the opening, the light receiving sensor and the transfer electrode are determined in a self-aligned manner. .

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A solid-state imaging device according to the present invention has a plurality of light receiving sensor units and a vertical transfer register arranged on one side of each light receiving sensor column, and a light receiving sensor unit between adjacent light receiving sensor units in the vertical direction. A structure in which the first and second transfer electrodes overlap and extend above, and an insulating film thicker than the gate insulating film is formed immediately below a vertical end of the transfer electrode extending between the light-receiving sensors. And

The method for manufacturing a solid-state imaging device according to the present invention comprises:
Forming a first-layer transfer electrode by forming an insulating film thicker than the gate insulating film on the semiconductor substrate via a gate insulating film at a position corresponding to each of the light-receiving sensors to be formed thereafter; Forming a conductive film serving as a second-layer transfer electrode on the entire surface including the first-layer transfer electrode via an interlayer insulating film;
Forming an opening corresponding to each light receiving sensor portion in the conductive film, patterning an interlayer insulating film and a thick insulating film through the opening, forming a light receiving sensor portion in the semiconductor substrate through the patterned opening, A step of patterning the film to form a second-layer transfer electrode.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 to 3 show an embodiment in which the solid-state imaging device of the present invention is applied to an interline transfer (IT) type CCD solid-state imaging device. In the CCD solid-state imaging device 19 according to the present embodiment, as shown in FIG. 1, a plurality of light receiving sensor units 11 serving as pixels are arranged in a matrix, and a vertical transfer register 12 is formed on one side of each light receiving sensor column. The end of each vertical transfer register 12 is connected to the horizontal transfer register 13, and the end of the horizontal transfer register 13 is connected to a charge diffusion device (not shown) such as a floating diffusion region or a floating gate.
And an output circuit 14 is connected thereto.

The vertical transfer register 12 is configured in a predetermined drive system, for example, a four-phase drive system, and applies a four-phase vertical drive pulse φV [φV ₁ , φV ₂ , φV] to each vertical transfer electrode.
₃ , φV ₄ ]. The horizontal transfer register 13 is configured in a predetermined drive system, for example, a two-phase drive system, and applies a two-phase horizontal drive pulse φH [φH ₁ , φ
H ₂ ] is applied.

As shown in FIGS. 2 and 3, the light receiving sensor section 11 is formed by forming, for example, a photodiode on one main surface of the semiconductor substrate 15. The light receiving sensor unit 11 is formed in a self-aligned manner with respect to the vertical transfer electrode 17 as described later.

In the vertical transfer register 12, the vertical transfer electrode 17 is formed, for example, in a two-layer polycrystalline silicon structure. That is, a first polycrystalline silicon film is formed on one main surface of the imaging region of the semiconductor substrate 15 via a gate insulating film 16 made of, for example, a silicon oxide film, a silicon nitride film or the like so as to correspond to each light receiving sensor unit 11. To form the first and third transfer electrodes 17A and 17C. Similarly, a second polycrystalline silicon film corresponding to each light receiving sensor 11
And the fourth transfer electrodes 17B and 17D are formed. These transfer electrodes 17A to 17D are repeatedly arranged in the vertical direction. Then, each of the transfer electrodes 17A to 17
D is applied with four-phase vertical drive pulses φV _{1 to} φV ₄ .

The first and third transfer electrodes 17 A and 17 C and the second and fourth transfer electrodes 17 B and 17 D are
Is formed through. The transfer electrodes 17A to 17D are formed in a band shape along the horizontal direction so as to be common to the respective vertical transfer registers 12. The transfer electrodes 17A and 17C made of the first-layer polycrystalline silicon film and the transfer electrodes 17B and 17D made of the second-layer polycrystalline silicon film are provided between the vertically adjacent pixels, that is, between the light-receiving sensor portions 11. 18 are formed.

In the present embodiment, as shown in FIG. 3, a gate insulating film is provided immediately below the vertical ends of the transfer electrodes 17 [17A to 17D] between the light receiving sensor units 11 adjacent to each other in the vertical direction. An insulating film (eg, a silicon oxide film, a silicon nitride film, etc.) 21 thicker than 18 is formed. In this example, the second-layer transfer electrodes 17B and 17D
The vertical electrode width W ₃ of the first-layer transfer electrode 17A,
17C is set from the vertical direction of the electrode width W ₄ in the large, this second layer transfer electrodes 17B, a thick insulating film 21 is provided directly below an end portion of the vertical 17D.

Although not shown, the second-layer transfer electrode 1 is not shown.
When the electrode widths of the transfer electrodes 17B and 17D are smaller than those of the transfer electrodes 17A and 17C of the first layer, the transfer electrodes 17A and 17A of the first layer
The thick insulating film 21 exists immediately below the vertical end of 17C.

[0028] CCD solid-state imaging device 1 according to the present embodiment
In 9, as usual, when image light is incident, signal charges are accumulated in each light receiving sensor unit 11 by photoelectric conversion.
This signal charge is transferred to, for example, the second-layer transfer electrodes 17B and 17B.
Data is read from the light receiving sensor unit 11 to the vertical transfer register 12 through a read gate unit (not shown) using D as a read gate electrode. This signal charge is sequentially transferred in the vertical transfer register 12 in the vertical direction, and the signal charge for each line is transferred to the horizontal transfer register 13. The signal charges of one line transferred to the horizontal transfer register 13 are sequentially transferred in the horizontal direction in the horizontal transfer register 13, converted into a voltage by the charge-voltage converter, and output as a pixel signal through the output circuit 14.

[0029] CCD solid-state imaging device 1 according to the present embodiment
According to No. 9, in the imaging area, the gate insulating film 16 is provided immediately below the transfer electrodes extending between the vertically adjacent light-receiving sensors 11, in this example, the vertical ends of the second-layer transfer electrodes 17B and 17D. By providing the thicker insulating film 21, a read pulse is applied to the second-layer transfer electrodes 17 </ b> B and 17 </ b> D also serving as a read gate electrode, and the signal charges of the light receiving sensor unit 11 are read to the vertical transfer register 12.
During the so-called charge reading, the potential under the second-layer transfer electrodes 17B and 17D between the light-receiving sensors 11 does not fluctuate (deeper). Therefore, the charge is not leaked to the light receiving sensor unit adjacent in the vertical direction, and the proper charge reading can be performed.

The second layer transfer electrodes 17B, 17D of electrode width W ₃ is the first layer transfer electrodes 17A, can be set larger than the electrode width W ₄ of 17C, the second-layer transfer electrodes 17B, 1
The disconnection accident of 7D is eliminated, and the transfer electrode 17 of the second layer is removed.
B, 17D resistance can be reduced. By reducing the resistance of the transfer electrode, the propagation delay of the drive pulse is reduced, and a decrease in the charge transfer capacity can be avoided.

Next, an embodiment of a method for manufacturing a solid-state image sensor according to the present invention will be described with reference to FIGS. In this example,
This is a case where the present invention is applied to the manufacture of the CCD solid-state imaging device 19 described above. Each drawing A shows a planar structure of a main part of the imaging region, and each drawing B shows an enlarged cross-sectional structure taken along the line AA of the corresponding drawing A.

First, as shown in FIGS. 4A and 4B, a gate insulating film 16 made of, for example, a silicon oxide film or a silicon nitride film is formed on one main surface of a semiconductor substrate 15 made of, for example, silicon.
Is formed, and a gate insulating film 16 is formed on the gate insulating film 16.
A thicker insulating film (for example, a silicon oxide film) 21 having a thickness t ₁ larger than the thickness t ₂ of the first-layer transfer electrode 17 to be formed later in this example is formed. Only the thick insulating film 21 is etched and removed in a lattice shape by a normal dry etching method, a wet etching method or the like so as to remain at a position corresponding to the light receiving sensor unit 11 to be formed thereafter. The formation of the thick insulating film 21 in the shape of a lattice enables the formation of the vertical transfer register together with the formation region.
A valley 31 is formed between the insulating films 21 adjacent in the vertical direction.

Note that a transfer channel region 32 (see FIG. 9C) is formed in advance in a region of the semiconductor substrate 15 where the vertical transfer register is formed.

Next, as shown in FIGS. 5A and 5B, a conductive film, in this example, a first polycrystalline silicon film 33 is formed on the entire surface including the thick insulating film 21, and the first polycrystalline silicon film 33 is formed. The band-shaped first and third vertical transfer electrodes 17A, 17A, 1 are patterned by patterning the silicon film 33 so as to be common to each vertical transfer register.
Form 7C.

At this time, the first polycrystalline silicon film 33
Thickness t ₂ of is set thinner than the thickness t ₁ of the thick insulating film 21. Since the first polycrystalline silicon film 33 is formed so as to be embedded in the valleys 31 between the vertically adjacent thick insulating films 21, the valleys 31 between the adjacent thick insulating films 21 after patterning are formed. 5A, the first and third transfer electrodes 17A and 17C are formed in a trough 31 in a U-shaped cross section.

Next, as shown in FIGS. 6A and 6B, a conductive film, for example, a second-layer polycrystalline silicon film 34 in this example is formed on the entire surface via an interlayer insulating film 18 such as a silicon oxide film. Then, on this second-layer polycrystalline silicon film 34,
A photoresist layer 36 having an opening at a position corresponding to the thick insulating film 21 is formed.
Is used as a mask to form an opening 37 in the second-layer polycrystalline silicon film 34.

In this embodiment, the vertical edge of the opening 37 exists inside the thick insulating film 21, and the horizontal edge preferably coincides with the edge of the thick insulating film 21. It is formed so as not to be hooked.

Next, as shown in FIGS.
The interlayer insulating film 18 and the thick insulating film 21 thereunder are selectively removed by etching. Further, ion implantation is performed through the opening 37 to form the light receiving sensor unit 11 using a photodiode on the semiconductor substrate 15 in a self-aligned manner with respect to the transfer electrode.

Next, as shown in FIGS. 8A and 8B, the second polycrystalline silicon film 34 is patterned by, for example, a normal dry etching method or a wet etching method to form a second polycrystalline silicon film 34.
And the fourth vertical transfer electrodes 17B and 17D are formed.
Thus, the vertical transfer register 12 is formed.

FIGS. 9A, 9B and 9C show cross-sectional structures taken along lines BB, CC and DD in FIG. 8A.

Thereafter, an interlayer insulating film and a passivation film are formed by a usual method, and a color filter, an on-chip microlens and the like are formed in the case of a color image pickup device, and the intended CCD solid-state image pickup device 19 is formed. obtain.

According to the method of manufacturing the solid-state imaging device 19 according to the present embodiment, the position of each light-receiving sensor unit 11 to be subsequently formed on the semiconductor substrate 15 corresponding to the imaging region via the gate insulating film 16. Correspondingly, after forming the thick insulating film 21 and forming the first and third vertical transfer electrodes 17A and 17C by the first-layer polycrystalline silicon film 33, an opening 37 is provided at the position of each thick insulating film 21. Since a second polycrystalline silicon film 34 is formed, and the interlayer insulating film 18 facing the opening 37 and the thick insulating film 21 thereunder are selectively etched and removed, the second polycrystalline silicon film is thereafter formed. Is patterned to form second and fourth vertical transfer electrodes 17B, 1B.
When 7D is formed, the second-layer vertical transfer electrodes 17B, 1 extending between the light receiving sensor units 11 adjacent in the vertical direction are formed.
A thick insulating film 21 exists immediately below the vertical end of 7D.

This means that the electrode width W ₃ of the second-layer transfer electrodes 17B and 17D extending between the light-receiving sensors 11 is formed larger than the electrode width W ₄ of the first-layer transfer electrodes 17A and 17C. Sometimes, a thick insulating film 21 exists directly below the vertical end.

Even when the position of the opening 37 is deviated from the normal position due to misalignment of the mask, the thick insulating film 21 exists immediately below the vertical ends of the transfer electrodes 17B and 17D of the second layer after patterning. .

When the electrode width W ₃ of the transfer electrodes 17B and 17D of the second layer is patterned smaller than the electrode width W ₄ of the transfer electrodes 17A and 17C of the first layer, the transfer electrodes 17A and 17C of the first layer are patterned. Thick insulating film 2 just below the vertical end of
There will be one.

Therefore, the second-layer transfer electrodes 17B and 17D extending between the light-receiving sensor portions 11 adjacent in the vertical direction are adjacent to the first-layer transfer electrodes 17A and 17C in the vertical direction, that is, the gate insulating film 16 is provided. It is not formed directly on top.
In addition, the processing margin of the second-layer transfer electrodes 17B and 17D extending between the light-receiving sensors can be increased, and the processing of the second-layer transfer electrodes 17B and 17D becomes easy.

The transfer electrodes 17B and 17D of the second layer can increase the electrode width W ₃ , so that the resistance of the electrodes can be reduced and the propagation delay of the applied drive pulse can be reduced. be able to.

In the process shown in FIG. 7, the second polycrystalline silicon film 3 is formed.
Since the light receiving sensor 11 is formed by ion implantation through the opening 37 of the fourth electrode 4, the light receiving sensor 11 is connected to the transfer electrodes 17A, 1A.
7C and the transfer electrodes 17B and 17D can be formed in a self-aligned manner.

Since the first-layer transfer electrodes 17A and 17C are formed so as to be embedded in the valleys 31 of the thick insulating film 21,
In the subsequent oxidation process such as formation of the interlayer insulating film 18 and the gate oxide film of the MOS transistor in the output circuit section, the amount of oxidation of the first-layer transfer electrodes 17A and 17C is suppressed, and the necessary and sufficient first-layer transfer electrodes 17A and 17C are suppressed. Transfer electrodes 17A, 17C
Enables the formation of

Since the first-layer transfer electrodes 17A and 17C are formed so as to be embedded in the valleys 31 of the thick insulating film 21, the transfer electrodes 17A and 17C are
The transfer electrodes 17B and 17D of the first layer are connected to the transfer electrodes 17 of the first layer.
Processing can be performed regardless of A, 17C.

Accordingly, when the signal charges of the light receiving sensor section 11 are read out to the vertical transfer register 12, the leakage of the charges between the light receiving sensor sections is prevented, and the driving pulses in the transfer electrodes 17B, 17D of the second layer are prevented. It is possible to easily manufacture a CCD solid-state imaging device capable of reducing propagation delay and suppressing a decrease in charge transfer capacity.

In the above example, the present invention is applied to an interline transfer (IT) type CCD solid-state imaging device.
It can also be applied to D solid-state imaging devices.

[0053]

The solid-state imaging device according to the present invention can reliably prevent the leakage of charges between the vertically adjacent light-receiving sensors when reading out the charges from the light-receiving sensors to the vertical transfer registers. In the vertical transfer electrode having the two-layer structure, the electrode width of the second-layer transfer electrode extending between the light-receiving sensors adjacent in the vertical direction can be increased.
Reduce electrode resistance, reduce propagation delay of drive pulse,
The charge transfer capacity can be improved. Therefore, a highly reliable solid-state imaging device can be provided.

According to the method of manufacturing a solid-state image pickup device according to the present invention, the solid-state image sensor 2 extending between the light-receiving sensors adjacent to each other in the vertical direction.
The vertical end of the vertical transfer electrode of the layer can be prevented from being formed on the gate insulating film so as to be adjacent to the vertical transfer electrode of the first layer. It is possible to increase the electrode width of the second-layer vertical transfer electrode extending between the adjacent light receiving sensor units. As a result, the electrode resistance can be reduced and the propagation delay of the drive pulse can be reduced.

The processing margin of the second-layer vertical transfer electrode can be increased, and the processing of the second-layer vertical transfer electrode can be facilitated. The light receiving sensor unit can be formed in a self-aligned manner with respect to the transfer electrode. The amount of progress of oxidation of the first layer of vertical transfer electrodes in the subsequent oxidation step can be suppressed, and a favorable first layer of vertical transfer electrodes can be formed.

Therefore, a highly reliable solid-state imaging device can be easily manufactured.

[Brief description of the drawings]

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

FIG. 2 is a plan view of a main part of an imaging region in FIG. 1;

FIG. 3 is a sectional view taken on line AA of FIG. 2;

FIG. 4A is a manufacturing step diagram (part 1) showing one embodiment of a method for manufacturing a solid-state imaging device according to the present invention. B It is an expanded sectional view on the AA line of FIG. 4A.

FIG. 5A is a manufacturing step diagram (part 2) illustrating one embodiment of a method for manufacturing a solid-state imaging device according to the present invention. FIG. 5B is an enlarged sectional view taken on line AA of FIG. 5A.

FIG. 6A is a manufacturing step diagram (part 3) illustrating one embodiment of a method for manufacturing a solid-state imaging device according to the present invention. 6B is an enlarged sectional view taken along line AA of FIG. 6A.

FIG. 7A is a manufacturing step diagram (part 4) illustrating one embodiment of a method for manufacturing a solid-state imaging device according to the present invention. B It is an expanded sectional view on the AA line of Drawing 7A.

FIG. 8A is a manufacturing step diagram (part 5) showing one embodiment of a method for manufacturing a solid-state imaging device according to the present invention. B is an enlarged cross-sectional view taken along line AA of FIG. 8A.

FIG. 9A is a cross-sectional view taken along line BB of FIG. 8A. B is a cross-sectional view taken along line CC of FIG. 8A. C It is sectional drawing on the DD line of FIG. 8A.

FIG. 10 is a configuration diagram showing a conventional solid-state imaging device.

FIG. 11 is a plan view of a main part of an imaging region in FIG. 10;

FIG. 12 is a sectional view taken on line EE of FIG. 11;

[Explanation of symbols]

11 # light receiving sensor section, 12 # vertical transfer register, 1
5 ° semiconductor substrate, 16 ° gate insulating film, 17A, 1
7C ‥‥ Transfer electrode of the first layer, 17B, 17D ‥‥ Transfer electrode of the second layer, 18 ‥‥ Interlayer insulating film, 21 ‥‥ Thick insulating film, 32 ‥‥ Transfer channel region, 33,34 ‥‥ Polycrystalline Silicon film, 36 ‥‥ photoresist layer, 37 ‥‥ opening

Claims (2)

[Claims] 1. A light-receiving device comprising: a plurality of light-receiving sensor units; and a vertical transfer register disposed on one side of each light-receiving sensor array, wherein a first-layer and a second-layer transfer are performed between vertically adjacent light-receiving sensor units. A solid-state imaging device, wherein electrodes are overlapped and an insulating film thicker than a gate insulating film is formed immediately below a vertical end of the transfer electrode extending between the light-receiving sensors. 2. A method according to claim 1, further comprising the steps of:
A step of forming an insulating film thicker than the gate insulating film at a position corresponding to each light-receiving sensor section to be formed; and forming a first-layer transfer electrode so as to be embedded in a valley formed by the thick insulating film. Forming a conductive film to be a second-layer transfer electrode on the entire surface including the first-layer transfer electrode via an interlayer insulating film; and forming openings in the conductive film corresponding to the light-receiving sensors. Forming a light-receiving sensor portion in the semiconductor substrate through the patterned opening; forming a light-receiving sensor portion in the semiconductor substrate through the patterned opening; A method for manufacturing a solid-state imaging device, comprising a step of forming a transfer electrode of a layer.