JP2000124438A - Solid-state image sensing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an amplification type solid-state image sensing device of high sensitivity by forming an optical pipe-like structure formed of a light screening material between an opening part of a light screening film and a semiconductor board surface. SOLUTION: A source and a drain of an amplification transistor are connected to an outside of an image sensing region by a second metallic wiring 7 formed in a first metallic wiring 6 and an upper layer of the first metallic wiring 6 interposing an insulation film 10. A light screening film 8 formed of a light screening material is formed in an upper layer of the second metallic wiring 7 interposing the insulation layer 10. An opening part for a photodiode is formed in the light screening film 8. The insulation layer 10 is etched to self-align to an opening part of the light screening film 8, and a second light screening film 9 is deposited conformally by an isotropical deposition process. The second light screening film 9 is etched back and a pipe-like structure of the second light screening film 9 consisting of a sidewall is obtained. As a result, enough sensitivity improvement effect can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a unit pixel structure of an amplification type solid-state imaging device and a method of manufacturing the amplification type solid-state imaging device. The present invention relates to an amplifying solid-state imaging device having high sensitivity and no sensitivity shading.

[0002]

2. Description of the Related Art A solid-state imaging device having an amplifying function inside a pixel by modulating the potential of a signal charge accumulating section with a signal charge generated by photoelectric conversion and modulating an amplifying transistor inside the pixel with the potential is amplified. It is called a solid-state imaging device and can operate with a low-voltage single power supply and can be equipped with a logic circuit such as a drive circuit on a chip. ing.

The basic configuration of a pixel in an amplification type solid-state imaging device is a photodiode for photoelectric conversion, a reset transistor for initializing the voltage of this photodiode, a transistor for amplification, a transistor for line selection, or a transistor for line selection. This is a line for capacitive coupling and connecting the photodiode and the gate of the amplification transistor.
Further, when temporarily storing the photoelectrically converted signal charge, a storage diode is provided in a region different from the photodiode, and a transfer gate is provided between the photodiode and the storage diode.

In order to reduce the noise of the photodiode, it is also possible to use a buried photodiode structure in which a PN junction region constituting the photodiode is buried in a semiconductor substrate.

[0005]

Incidentally, a plurality of transistor structures are formed inside a unit pixel of an amplification type solid-state imaging device, and a metal for driving the transistor or outputting a signal from the transistor to the outside of the pixel is used. Wiring structure is included. Further, it is necessary to form a light-shielding film structure in a form electrically separated from these metal wiring structures to prevent light from entering a region other than the photodiode. The light-shielding film structure limits light incidence inside the unit pixel, and thus defines the aperture of the photodiode.

As described above, in an amplification type solid-state imaging device including a plurality of metal material layer structures inside a unit pixel, a new optical design problem occurs inside the unit pixel. One is a mismatch with a microlens structure for improving a substantial aperture ratio of a photodiode, which can be said to be an essential structure in recent miniaturization of unit pixels.
That is, in the CCD, the height of the opening of the light-shielding film that defines the opening of the photodiode from the semiconductor substrate is designed to be extremely low, and the microlens for condensing incident light to the photodiode is easily designed. On the other hand, as described above, in the amplification type solid-state imaging device, the height of the opening of the light-shielding film from the semiconductor substrate is inevitably increased, and the design of the microlens becomes extremely difficult. I will. The other is a problem of so-called sensitivity shading in which a difference in sensitivity occurs between the center of the imaging region and the periphery of the imaging region. This is because the light incident angle formed between the incident light and the surface of the semiconductor substrate is 90 ° at the center of the imaging area.
On the other hand, it is not 90 ° in the periphery of the imaging region. That is, since the opening of the light-shielding film is formed in a portion higher than the semiconductor substrate as described above, when the light incident angle is not 90 °, the projection portion of the light-shielding film after the opening of the light-shielding film onto the semiconductor substrate is formed. Does not coincide with the photodiode, and the effect is remarkable especially in the amplification type solid-state imaging device in which the opening of the light shielding film is formed at a high position.

On the other hand, as a structure for preventing color mixing and blooming due to long-wavelength light having a low absorptance at the semiconductor substrate and reaching the deep portion of the semiconductor substrate, a P-type semiconductor substrate has
Forming a P-type well region and forming a photodiode N layer in the P-type well, a so-called N-sub. The structure is known to be effective. According to this structure, by applying an appropriate bias voltage between the N-type semiconductor substrate and the P-type well region, excessive charges generated in the deep part of the semiconductor substrate can be N-sub. And the above-described color mixing and blooming can be prevented.

This N-sub. In the structure, it is important to fix the potential of the P-type well region. Ideally, a contact structure to the P-type well region is provided inside each unit pixel structure, and low-resistance metal wiring is used to cover the entire imaging region. , It is desirable to stabilize the P-type well potential,
Providing a new contact structure inside a pixel contradicts the demand for miniaturization of a unit pixel.

[0009]

According to the present invention, in order to solve the above-mentioned problem caused by the fact that the opening of the light shielding film is formed at a higher position from the semiconductor substrate, the opening of the light shielding film must be opened. An optical pipe-shaped structure made of a light-shielding material is formed up to the surface of the semiconductor substrate, so that only the light-shielding film opening can be considered in the design of the microlens. A solid-state imaging device can be obtained.

In addition, even when the light incident angle is other than 90 ° in the periphery of the imaging region, all the incident light is incident on the photodiode by the optical pipe structure.
An amplification type solid-state imaging device in which sensitivity shading does not occur can be obtained.

Further, according to the present invention, the light-shielding film and the optical pipe structure are electrically connected to the semiconductor substrate on the photodiode surface or the same conductivity type region as the semiconductor substrate surface well, so that light is shielded outside the imaging region. By electrically connecting the film to the semiconductor substrate or semiconductor substrate surface well, it is possible to stabilize the semiconductor substrate potential or semiconductor substrate surface well potential inside the imaging region without providing a new contact structure inside the imaging region. Becomes

According to the present invention, in order to solve the above-mentioned problem caused by the fact that the opening of the light-shielding film is formed at a higher position from the semiconductor substrate, the distance between the opening of the light-shielding film and the surface of the semiconductor substrate is increased. In addition, since an optical pipe-shaped structure made of a light-shielding material is formed, it is possible to design a microlens in consideration of only the light-shielding film opening,
A high-sensitivity amplification type solid-state imaging device can be obtained.

In addition, even when the light incident angle is other than 90 ° in the periphery of the imaging area, all the incident light enters the photodiode by the optical pipe structure.
An amplification type solid-state imaging device in which sensitivity shading does not occur can be obtained.

Further, according to the present invention, the light-shielding film and the optical pipe structure are electrically connected to the semiconductor substrate on the photodiode surface or the same conductivity type region as the semiconductor substrate surface well. By electrically connecting the film to the semiconductor substrate or semiconductor substrate surface well, it is possible to stabilize the semiconductor substrate potential or semiconductor substrate surface well potential inside the imaging region without providing a new contact structure inside the imaging region. Becomes

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to examples.

FIG. 1 is a sectional structural view for explaining a unit pixel structure of an amplifying type solid-state imaging device according to a first embodiment of the present invention. 3 shows a cross-sectional structure of a region including a diode. Except for the structure shown in FIG. 1, the configuration is the same as that of the conventional amplification type solid-state imaging device, and thus the description is omitted.

The p-type semiconductor substrate 1 may be an n-type semiconductor substrate as long as the region for the diode / transistor operation on the surface side is a p-type region such as a p-well structure.

An n-type impurity region 2 for a photodiode and an n-type impurity region 4 for a storage diode
Can be formed by, for example, phosphorus ion implantation. The signal charges photoelectrically converted in the photodiode are stored in the photodiode and then transferred and stored in the storage diode via the transfer gate 5 formed adjacent to the photodiode.

The transfer gate 5 is obtained by thermally oxidizing the surface of the p-type semiconductor substrate 1, depositing, for example, polysilicon as a gate electrode by CVD or the like, and further combining photolithography with etching such as RIE as shown in FIG. It can be processed and formed into the shape shown.

N-type impurity layer 4 forming storage diode
First through a contact hole
The metal wiring 6 is connected. This first metal wiring 6
The gate voltage connected to the gate electrode (not shown) of the amplifying transistor inside the unit pixel and thus applied to the gate electrode of the amplifying transistor is modulated by the amount of signal charges stored in the storage diode.

The signal charge stored in the storage diode is discharged to a reset drain (not shown) via a reset gate (not shown) provided adjacent to the storage diode.

The structure of the amplifying transistor and the structure of the reset transistor are the same as those of the conventional amplifying type solid-state imaging device, and are general structures that can be formed by a normal MOS process. The description about is omitted.

The source and the drain of the amplifying transistor (not shown) are located outside the imaging region by a first metal wiring 6 and a second metal wiring 7 formed on the first metal wiring 6 via an insulating film 10. Connected.

A light-shielding film 8 made of, for example, a light-shielding material containing aluminum as a main component is formed on the second metal wiring 7 via an insulating layer 10.

An opening is formed in the light-shielding film 8 for entering light into the photodiode. The insulating layer 10 in this opening reaches the semiconductor substrate 1 by anisotropic etching such as RIE. Etch to the extent that it does not.

This step will be described with reference to FIG.

FIG. 6 is a schematic sectional view of a unit pixel for explaining a method of manufacturing an amplification type solid-state image pickup device according to the first embodiment of the present invention, in which only a light shielding film structure in a photodiode region is described. Therefore, the transfer gate, metal wiring, and the like are omitted.

FIG. 6A shows a state in which an opening for a photodiode is formed in the light shielding film 8.

Subsequently, the insulating layer 10 is etched by anisotropic etching such as RIE in a self-aligned manner with respect to the opening of the light shielding film 8, thereby obtaining the structure shown in FIG. Thereafter, when the second light-shielding film 9 is conformally deposited by an isotropic deposition process such as CVD of tungsten, a structure shown in FIG. 6C is obtained.

Next, the second light-shielding film 9 is etched back by, for example, anisotropic etching such as RIE, thereby forming a pipe-shaped second light-shielding film 9 having a so-called sidewall shown in FIG. Can be obtained.

Thereafter, an insulating film is deposited by, for example, CVD or the like for flattening the light-shielding film 8 and the second light-shielding film 9, and the surface of the insulating film 10 is flattened by a process such as etch-back or CMP. .

Further, the structure shown in FIG. 1 can be obtained by forming an on-chip micro lens 11 in order to improve the substantial aperture ratio of the photodiode.

The effect of the structure of FIG. 1 will be described with reference to FIGS.

In the amplification type solid-state imaging device having the conventional structure (FIG. 9), the height of the microlens 11 as viewed from the semiconductor substrate 1 due to the existence of the plurality of metal wiring layers (6, 7) formed inside the unit pixel. Will be higher. Therefore,
If the light-shielding light condensing by the microlens 11 formed to improve the substantial aperture ratio of the photodiode is designed so as not to be blocked by the opening of the light-shielding film 8, the focal point of the microlens 11 is higher than the semiconductor substrate 1. As a result, light incident on the peripheral portion of the microlens 11 is incident on a region other than the photodiode, and the sensitivity of the photodiode is not sufficiently improved (FIG. 5).

On the other hand, according to the first embodiment of the present invention, the light incident on the area other than the photodiode in the conventional structure is converted into the second light shielding film formed in a pipe shape as shown in FIG. 9 and is incident on the photodiode, whereby a sufficient sensitivity improving effect can be obtained.

Similarly, in the conventional structure, the incident angle of the incident light on the semiconductor substrate at the pixels in the peripheral portion of the chip is 90 °.
In this case, so-called sensitivity shading occurs, in which the amount of light incident on the photodiode decreases compared to the pixel at the center of the chip, and the sensitivity gradually decreases toward the periphery of the chip. According to the first embodiment of the present invention, regardless of the incident angle of the incident light, all the incident light is incident on the photodiode by reflection by the pipe-shaped second light-shielding film 9, so that the sensitivity shading is completely performed. Can be prevented.

FIG. 2 is a sectional structural view for explaining a unit pixel structure of an amplification type solid-state image pickup device according to a second embodiment of the present invention. 3 shows a cross-sectional structure of a region including a diode. Except for the structure shown in FIG. 2, the configuration is the same as that of the conventional amplification-type solid-state imaging device, and a description thereof will be omitted.

The p-type semiconductor substrate 1 may be an n-type semiconductor substrate as long as the region for the diode / transistor operation on the surface side is a p-type region such as a p-well structure.

N-type impurity region 2 for photodiode and N-type impurity region 4 for storage diode
Can be formed by, for example, phosphorus ion implantation. In this embodiment, the structure of the photodiode is P
A so-called embedded photodiode having a structure in which an N-junction is embedded in a semiconductor substrate is used. The p-type impurity region 3 for the buried photodiode can be formed by, for example, boron ion implantation.

The signal charges photoelectrically converted in the photodiode are accumulated in the photodiode and then formed on a transfer gate 5 formed adjacent to the photodiode.
Through the storage diode.

The transfer gate 5 is formed by, for example, depositing polysilicon or the like as a gate electrode by CVD or the like after thermal oxidation of the surface of the p-type semiconductor substrate 1 and further combining photolithography and etching such as RIE as shown in FIG. It can be processed and formed into the shape shown.

N-type impurity layer 4 forming storage diode
First through a contact hole
The metal wiring 6 is connected. This first metal wiring 6
The gate voltage connected to the gate electrode (not shown) of the amplifying transistor inside the unit pixel and thus applied to the gate electrode of the amplifying transistor is modulated by the amount of signal charges stored in the storage diode.

The signal charge stored in the storage diode is discharged to a reset drain (not shown) via a reset gate (not shown) provided adjacent to the storage diode.

The amplifying transistor structure and the reset transistor structure are the same as those of the conventional amplifying type solid-state imaging device, and are general structures that can be formed by a normal MOS process. The description about is omitted.

The source and the drain of the amplifying transistor (not shown) are located outside the imaging region by the first metal wiring 6 and the second metal wiring 7 formed on the first metal wiring 6 via the insulating film 10. Connected.

A light-shielding film 8 made of, for example, a light-shielding material containing aluminum as a main component is formed on the second metal wiring 7 via an insulating layer 10.

An opening is formed in the light-shielding film 8 for entering light into the photodiode. The insulating layer 10 in the opening reaches the semiconductor substrate 1 by anisotropic etching such as RIE. Etch to the extent that it does not.

This step will be described with reference to FIG.

FIG. 7 is a schematic sectional structural view of a unit pixel for explaining a method of manufacturing an amplification type solid-state imaging device according to a second embodiment of the present invention, in which only a light shielding film structure in a photodiode region is described. Therefore, the transfer gate, metal wiring, and the like are omitted.

FIG. 7A shows a state in which an opening for a photodiode is formed in the light shielding film 8.

Subsequently, the insulating layer 10 is etched by anisotropic etching such as RIE in a self-aligned manner with respect to the opening of the light-shielding film 8 to obtain the structure shown in FIG. 7B.

After that, when the second light-shielding film 9 is conformally deposited by an isotropic deposition process such as CVD of tungsten, the structure shown in FIG. 7C is obtained.

Next, the second light-shielding film 9 is etched back by anisotropic etching such as RIE to form a pipe-shaped second light-shielding film 9 having a so-called sidewall shown in FIG. Can be obtained.

Thereafter, an insulating film is deposited by, for example, CVD or the like for flattening the light-shielding film 8 and the second light-shielding film 9, and the surface of the insulating film 10 is flattened by a process such as etch-back or CMP. .

Further, the structure shown in FIG. 2 can be obtained by forming an on-chip micro lens 11 in order to improve the substantial aperture ratio of the photodiode.

The effect of the second embodiment of the present invention shown in FIG. 2 is the same as the effect of the first embodiment, and the description thereof is omitted, but in this embodiment, there are some points. There is an effect exceeding the effect of the first embodiment.

This is because the second light-shielding layer 9 formed in a pipe shape is connected to the p-type impurity region 3 of the buried photodiode.

One is that the second light-shielding layer 9 formed in a pipe shape is filled with the p-type impurity region 3 of the buried photodiode.
Since the photodiode and the other area are optically completely separated from each other by the connection, the leakage of light entering and shielding into the area other than the photodiode is completely eliminated.

The other is a second light shielding film 9 connected to the p-type impurity region 3 of the buried photodiode.
Is connected to the first light-shielding film 8. Therefore, the light-shielding film 8 and the light-shielding film 9 have not only the function of a simple light-shielding film but also the photodiode p-type impurity region 3 and the p-type semiconductor substrate 1 or It has a function as a shunt wiring of a p-type well structure. Therefore, it is possible to prevent the potential of the photodiode p-type impurity region 3 and the p-type semiconductor substrate 1 or the p-type well structure from being locally unstable due to the incidence of spot light or the like.

In particular, the light-shielding film 8 is set to p outside the imaging region.
By taking a structure in contact with the type semiconductor substrate 1 or the p-type well structure, the effect of stabilizing the potential can be further ensured.

FIG. 3 is a sectional structural view for explaining a unit pixel structure of an amplification type solid-state image pickup device according to a third embodiment of the present invention. 3 shows a cross-sectional structure of a region including a diode. Except for the structure shown in FIG. 3, the configuration is the same as that of the conventional amplification type solid-state imaging device, and a description thereof will be omitted.

The p-type semiconductor substrate 1 may be an n-type semiconductor substrate as long as the region for diode / transistor operation on the surface side is a p-type region such as a p-well structure.

N-type impurity region 2 for photodiode and n-type impurity region 4 for storage diode
Can be formed by, for example, phosphorus ion implantation.

In this embodiment, the structure of the photodiode is a so-called embedded photodiode having a structure in which a PN junction for forming a diode is embedded in a semiconductor substrate.

The p-type impurity region 3 for the buried photodiode can be formed by, for example, boron ion implantation.

The signal charges photoelectrically converted in this photodiode are accumulated in the photodiode and then formed in a transfer gate 5 formed adjacent to the photodiode.
Through the storage diode.

The transfer gate 5 is obtained by thermally oxidizing the surface of the p-type semiconductor substrate 1, depositing, for example, polysilicon or the like as a gate electrode by CVD or the like, and further combining photolithography and etching such as RIE as shown in FIG. It can be processed and formed into the shape shown.

N-type impurity layer 4 forming storage diode
First through a contact hole
The metal wiring 6 is connected. This first metal wiring 6
The gate voltage connected to the gate electrode (not shown) of the amplifying transistor inside the unit pixel and thus applied to the gate electrode of the amplifying transistor is modulated by the amount of signal charges stored in the storage diode.

The signal charge stored in the storage diode is discharged to a reset drain (not shown) via a reset gate (not shown) provided adjacent to the storage diode. The amplifying transistor structure and the reset transistor structure are the same as those of the conventional amplifying type solid-state imaging device, and are general structures that can be formed by a normal MOS process. Omitted.

The source and the drain of the amplifying transistor (not shown) are located outside the imaging region by the first metal wiring 6 and the second metal wiring 7 formed on the first metal wiring 6 via the insulating film 10. Connected.

A light-shielding film 8 made of a light-shielding material containing, for example, aluminum as a main component is formed on the second metal wiring 7 via an insulating layer 10.

An opening is formed in the light-shielding film 8 for light incident on the photodiode. The insulating layer 10 in this opening reaches the semiconductor substrate 1 by anisotropic etching such as RIE. Etch to the extent that it does not.

This step will be described with reference to FIG.

FIG. 8 is a schematic sectional structural view of a unit pixel for explaining a method of manufacturing an amplification type solid-state imaging device according to a third embodiment of the present invention, in which only a light shielding film structure in a photodiode region is described. Therefore, the transfer gate, metal wiring, and the like are omitted.

FIG. 8A shows a state in which an opening for a photodiode is formed in the light shielding film 8.

Subsequently, the insulating layer 10 is etched by anisotropic etching such as RIE in a self-aligning manner with respect to the opening of the light-shielding film 8 to obtain the structure shown in FIG.

In this embodiment, in order to prevent the p-type impurity region 3 inside the semiconductor substrate 1 from being etched in the subsequent steps, the material of the second light shielding film 9 is anisotropically etched here. A light-transmitting material 12 having an etching resistance to the resist is deposited (FIG. 8C). As a method for depositing this etching-resistant material, a method of depositing titanium nitride by sputtering, for example, in the order of several hundred square meters is possible. After that, when the second light-shielding film 9 is conformally deposited by an isotropic deposition process such as CVD of tungsten, the structure shown in FIG. 8D is obtained.

Next, the second light-shielding film 9 is etched back by anisotropic etching such as RIE to form a pipe-shaped second light-shielding film 9 having a so-called sidewall shown in FIG. Can be obtained.

Thereafter, an insulating film is deposited by, for example, CVD or the like for flattening the light-shielding film 8 and the second light-shielding film 9, and the surface of the insulating film 10 is flattened by a process such as etch-back or CMP. .

Further, the structure shown in FIG. 3 can be obtained by forming an on-chip micro lens 11 in order to improve the substantial aperture ratio of the photodiode.

The effect of the third embodiment of the present invention shown in FIG. 3 is the same as the effect of the second embodiment, and the description thereof will be omitted. However, in this embodiment, there are some points. There is an effect exceeding the effect of the first embodiment.

This is because the light-transmitting thin film 12 is formed between the second light-shielding layer 9 formed in a pipe shape and the p-type impurity region 3 of the buried photodiode.

That is, the effect of protecting the semiconductor substrate 1 in the step of processing the second light-shielding layer 9 into a pipe shape (FIGS. 8D and 8E). For example, when the second light-shielding film 9 is made of tungsten, a fluorine-based gas having a high vapor pressure of a reaction product is generally used in the anisotropic etching. Since etching of the semiconductor substrate 1 by the system gas may occur and the p-type impurity region 3 for the buried photodiode may be etched, sufficient over-etching may not be performed in some cases. However, according to this embodiment, such a problem does not occur because titanium nitride having resistance to the anisotropic etching is used as the translucent thin film 12.

Further, FIGS. 3 and 8 show an example in which a titanium nitride thin film having a thickness of several hundreds of mm is used as the light-transmitting conductive thin film 12, but the light-transmitting light may be sacrificed as necessary. It is also possible to substitute with a thin film of nature. In this case, the light-shielding films 8 and 9 and the buried photodiode p-type impurity region 3 are not electrically connected to each other. Between them, a capacitive coupling is formed via an extremely thin insulating light-transmitting thin film 12, and therefore, the photodiode p-type impurity region 3 and the p-type semiconductor substrate 1 are locally localized due to incidence of spot light or the like. Alternatively, it is possible to prevent the potential of the p-type well structure from becoming unstable.

In particular, the light-shielding film 8 is set to p
By taking a structure in contact with the type semiconductor substrate 1 or the p-type well structure, the effect of stabilizing the potential can be further ensured.

In addition, various modifications can be made without departing from the gist of the present invention.

[0087]

According to the present invention, in order to solve the above-mentioned problem caused by the fact that the opening of the light-shielding film is formed at a higher position from the semiconductor substrate, the light-shielding film extends from the open portion of the light-shielding film to the surface of the semiconductor substrate. Since an optical pipe-shaped structure made of a light-shielding material is formed between them, a design that considers only the light-shielding film opening in the microlens design is possible. Obtainable.

In addition, even when the light incident angle is other than 90 ° in the periphery of the image pickup area, all the incident light enters the photodiode by this optical pipe structure.
An amplification type solid-state imaging device in which sensitivity shading does not occur can be obtained.

Further, according to the present invention, since the light-shielding film and the optical pipe structure are electrically connected to the semiconductor substrate on the photodiode surface or the same conductive type region as the semiconductor substrate surface well, light is shielded outside the imaging region. By electrically connecting the film to the semiconductor substrate or semiconductor substrate surface well, it is possible to stabilize the semiconductor substrate potential or semiconductor substrate surface well potential inside the imaging region without providing a new contact structure inside the imaging region. Becomes

[Brief description of the drawings]

FIG. 1 is a sectional structural view for explaining a unit pixel structure of an amplification type solid-state imaging device according to a first embodiment of the present invention.

FIG. 2 is a sectional structural view for explaining a unit pixel structure of an amplification type solid-state imaging device according to a second embodiment of the present invention.

FIG. 3 is a sectional structural view for explaining a unit pixel structure of an amplification type solid-state imaging device according to a third embodiment of the present invention.

FIG. 4 is a schematic cross-sectional structural view of the unit pixel for describing incident light in the unit pixel of the amplification type solid-state imaging device according to the first embodiment of the present invention.

FIG. 5 is a schematic cross-sectional structural view of a unit pixel for describing incident light in the unit pixel of the conventional amplification type solid-state imaging device.

FIG. 6 is a schematic sectional structural view for explaining a method of manufacturing the amplification type solid-state imaging device according to the first embodiment of the present invention.

FIG. 7 is a schematic sectional structural view for explaining a method of manufacturing an amplification type solid-state imaging device according to a second embodiment of the present invention.

FIG. 8 is a schematic sectional structural view for explaining a method of manufacturing an amplification type solid-state imaging device according to a third embodiment of the present invention.

FIG. 9 is a sectional structural view for explaining a unit pixel structure of a conventional amplification type solid-state imaging device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... p-type semiconductor substrate 2 ... photodiode n-type impurity region 3 ... buried photodiode p-type impurity region 4 ... storage diode n-type impurity region 5 ... transfer gate electrode 6 ... 1st metal wiring 7 ... 2nd metal wiring 8 ... First light-shielding film 9 Second light-shielding film 10 Insulating layer 11 Microlens 12 Translucent thin film

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4M118 AA01 AA05 AB01 BA14 CA03 CA04 CA18 CA32 CA40 DD12 EA06 FA06 FA33 GA09 GB03 GB07 GB11 GB15 GB19 GD04 GD07 5C024 AA01 CA03 CA10 CA12 CA31 FA01 GA01 GA33 GA51 HA10

Claims (9)

[Claims] A plurality of unit pixels are two-dimensionally arranged on a semiconductor substrate, and each unit pixel includes a photodiode for photoelectric conversion and a storage diode for storing signal charges obtained by the photodiode. A transfer transistor for transferring the signal charge obtained by the photodiode to the storage diode, a reset transistor for resetting the signal charge stored in the storage diode, and an amplification transistor modulated by the signal charge stored in the storage diode And a signal reading unit for reading a signal voltage from the amplification transistor, wherein the storage diode, the transfer transistor, and the amplification unit are provided to block incident light to a region excluding the photodiode. Made of light-shielding material on transistors, reset transistors, etc. An optical film is formed, and the light shielding film is formed in a pipe shape in contact with an opening formed in the first light shielding film formed on a surface parallel to the semiconductor substrate surface and an opening formed in the first light shielding film. An amplification-type solid-state imaging device comprising a combination with a second light-shielding film. 2. A plurality of unit pixels are two-dimensionally arranged on a semiconductor substrate. Each unit pixel has a photodiode for photoelectric conversion, and a storage diode for storing signal charges obtained by the photodiode. A transfer transistor for transferring the signal charge obtained by the photodiode to the storage diode, a reset transistor for resetting the signal charge stored in the storage diode, and an amplification transistor modulated by the signal charge stored in the storage diode And an amplifying solid-state imaging device provided with a signal reading unit that reads a signal voltage from an amplifying transistor, wherein the photodiode has a first conductivity type semiconductor substrate or a first conductivity type impurity well structure; A second conductive type opposite to the first conductive type formed inside the semiconductor substrate near the surface of the semiconductor substrate; A first PN junction formed by an electric impurity region; a first conductivity type impurity region formed near the semiconductor substrate surface; and a second PN junction formed inside the semiconductor substrate near the semiconductor substrate surface. A second PN junction formed by a conductive type impurity region, and a storage transistor, a transfer transistor, an amplification transistor, and a reset transistor for blocking incident light to a region excluding the photodiode. And the like, a light-shielding film made of a light-shielding material is formed, the light-shielding film is formed of a conductive material, and the light-shielding film is formed of the first conductivity type formed near the surface of the photodiode. An amplifying type solid-state imaging device, which is electrically connected to the impurity layer of (1). 3. The light-shielding film is electrically connected to the semiconductor substrate of the first conductivity type or the impurity well region of the first conductivity type in a region other than a region where the unit pixels are two-dimensionally arranged. 3. The method according to claim 2, wherein
The solid-state imaging device according to any one of the preceding claims. 4. The light-shielding film is in contact with a first light-shielding film made of a first material and formed on a first plane parallel to a surface of the semiconductor substrate, and an opening of the first light-shielding film. 4. The amplification type solid-state imaging device according to claim 1, further comprising a second light-shielding film formed of a pipe and formed of a second material different from the first material. 5. The amplifying solid-state imaging device according to claim 4, wherein said first material is a material mainly containing aluminum, and said second material is a material mainly containing tungsten. apparatus. 6. A thin-film electrode made of a light-transmitting and conductive material is formed on the surface of the photodiode, and the light-shielding film is formed near the surface of the photodiode via the thin-film electrode. 6. The semiconductor device according to claim 2, wherein the first conductive type impurity part layer is electrically connected to the first conductive type impurity part layer.
The solid-state imaging device according to any one of the preceding claims. 7. The amplification type solid-state imaging device according to claim 6, wherein said thin film electrode is made of titanium nitride. 8. A plurality of unit pixels are two-dimensionally arranged on a semiconductor substrate. Each unit pixel includes a photodiode for photoelectric conversion, and a storage diode for storing signal charges obtained by the photodiode. A transfer transistor for transferring the signal charge obtained by the photodiode to the storage diode, a reset transistor for resetting the signal charge stored in the storage diode, and an amplification transistor modulated by the signal charge stored in the storage diode And a signal reading unit for reading a signal voltage from the amplification transistor are provided. In order to block incident light to a region excluding the photodiode, the signal reading unit is provided on the storage diode, the transfer transistor, the amplification transistor, the reset transistor, and the like. Amplified solid with light-shielding film made of light-shielding material A method of manufacturing an image device, comprising: a step of etching at least a first light-shielding film formed on a surface parallel to the semiconductor substrate; and a step of self-aligning the light-shielding film after etching the light-shielding film. Etching a lower insulating layer structure, etching the insulating layer structure and then isotropically depositing a second light-shielding film, etching the second light-shielding film by anisotropic etching A method of manufacturing an amplification type solid-state imaging device, comprising: a step of performing back processing. 9. The amplification method according to claim 8, further comprising, after the etching of the insulating layer structure, depositing a thin film having an etching resistance to the etch-back processing of the second light-shielding film. Manufacturing method of a solid-state imaging device.