JP2006202789A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device having improved element characteristics by suppressing the deposition of impurities from a silicon oxide film (reflow film) for flattening that covers the surface, enhances uniformity in a sensitivity ratio, improves a sensitivity level or prevents deterioration in characteristics, and prevents variations in a threshold voltage at a photoelectric conversion section in a contact section. <P>SOLUTION: The semiconductor device has: a wiring takeout terminal including: a photoelectric conversion section formed on the surface of a semiconductor substrate, and the surface of the semiconductor substrate is covered with a reflow film and a protective film formed on the upper layer of the reflow film. The protective film contains a final protective film and a lower-layer protective film formed on the lower layer of the final protective film. The surface of the reflow film is covered with a lower-layer protective film made of an insulating film film-formed by a non-plasma process, and the wiring take-out terminal is formed on the upper layer of the lower-layer protective film. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor device and a manufacturing method thereof, and more particularly to water resistance of a contact portion.

  A CCD solid-state imaging device used for an area sensor or the like includes a photoelectric conversion unit such as a photodiode and a charge transfer unit including a charge transfer electrode for transferring a signal charge from the photoelectric conversion unit. A plurality of charge transfer electrodes are arranged adjacent to each other on a charge transfer path formed on the semiconductor substrate, and are sequentially driven.

  In recent years, in solid-state imaging devices, the number of imaging pixels has increased to more than gigapixels, but with the increase in the number of pixels, there is an increasing demand for improving the sensitivity of the photoelectric conversion unit.

  For this reason, miniaturization and higher sensitivity of the photoelectric conversion unit are progressing, and prevention of contamination of the photodiode unit which is the photoelectric conversion unit is an important issue.

  Conventionally, a silicon nitride film (SiN) formed by plasma CVD is used as the final protective film of the element. However, there is a problem that the sensitivity becomes non-uniform when the thickness of the silicon nitride film varies on the photodiode. Further, since the refractive indexes of the silicon nitride film and the silicon oxide film formed below the silicon nitride film are different, reflection at the interface may occur and the sensitivity may be lowered.

  Therefore, the above problem can be solved by etching away the silicon nitride film on the photodiode.

  However, the silicon oxide film formed under the silicon nitride film is used as a reflow film for planarization, and a PSG or BPSG film that is a silicon oxide film containing impurities such as boron or phosphorus is used. It is often done. For this reason, boron or phosphorus in the exposed silicon oxide film reacts with moisture in the atmosphere and precipitates, blocking the optical path on the photodiode, and increasing the number of scratches.

  Therefore, the applicants do not include a final protective film on the surface of the photoelectric conversion unit, and the lower protective film made of a material whose refractive index is closer to the reflow film than the final protective film is formed on the surface of the reflow film. Has proposed a solid-state imaging device coated with (Patent Document 1).

  As this lower protective film, a silicon oxide film formed by a plasma CVD method is used. Since the reflow film is covered with this silicon oxide film, impurities such as boron and phosphorus released from the reflow film are present. It is possible to prevent exposure to the atmosphere, and it is possible to prevent precipitation of the reaction product on the surface of the reflow film due to the reaction between the impurities and the atmosphere.

JP-A-2004-200320

  In the photoelectric conversion portion constituting the pixel, the silicon oxide film formed under the lower protective film is also removed, although the final protective film is not formed although it is covered with the lower protective film. There is little occurrence of a reaction between boron or phosphorus in the film and moisture. However, the wiring, that is, the aluminum for contact for external extraction, in the region where the connecting portion of the latitude line is formed, if the insulating film formed under the lower protective film is positively active, When it is used as a reflow film and is composed of a PSG or BPSG film that is a silicon oxide film containing impurities such as boron or phosphorus, aluminum is corroded by phosphoric acid reaction by phosphorus in the exposed silicon oxide film. Or swelled on the through hole, which may cause a short circuit of the aluminum wiring.

Further, since it is formed by the plasma CVD method, there is a problem in that the threshold voltage _Vth of the device after completion is caused by the influence of the charge charge due to the plasma irradiated on the surface of the semiconductor substrate at the time of film formation.

The present invention has been made in view of the above circumstances, and in the contact portion, the precipitation of impurities from the planarizing silicon oxide film (reflow film) covering the surface is suppressed, the sensitivity ratio is improved, and the sensitivity is improved. The purpose is to improve the level or prevent characteristic deterioration.
It is another object of the present invention to provide a semiconductor device having excellent element characteristics by preventing variation in threshold voltage in a photoelectric conversion unit.

  Therefore, the present invention includes a photoelectric conversion portion formed on the surface of a semiconductor substrate, the surface of the semiconductor substrate is covered with a reflow film and a protective film formed on an upper layer of the reflow film, and a part of the protective film The protective film includes a final protective film and a lower protective film formed thereunder, and a surface of the reflow film is formed by a non-plasma process. The wiring is covered with a lower protective film made of an insulating film, and the wiring is formed in an upper layer of the lower protective film.

  According to such a configuration, the reflow film is covered with a lower protective film made of an insulating film formed by a non-plasma process, and the wiring is formed on the upper layer of the lower protective film. It is possible to prevent the impurities to be exposed to the atmosphere, and to prevent precipitation on the surface of the reflow film due to the reaction with the atmosphere. In addition, since plasma charging can be prevented, variation in threshold voltage Vth can be prevented and characteristics can be improved. Here, it is desirable that the lower protective film is dense (preferably more than the reflow film) to such an extent that the impurity gas can be prevented from passing therethrough. Therefore, the black scratch defect at the time of light is prevented. It is desirable to use a material having a refractive index close to that of the reflow film. Thereby, reflection at the interface between the reflow film and the lower protective film is reduced, and a reduction in sensitivity can be prevented. Here, the final protective film refers to the uppermost protective film, and a silicon nitride film is usually used. Note that the thickness of the insulating film such as a silicon nitride film formed by plasma CVD varies significantly depending on the impedance of the entire wafer and the impedance of the outermost surface. Since the aluminum wiring for the area sensor peripheral circuit is formed close to the pixel end, the film thickness locally changes at the pixel center and the periphery. Since the reflectance of incident light varies depending on the refractive index n and the film thickness t, the sensitivity and sensitivity ratio can be improved by not using a plasma CVD film that tends to have a non-uniform film thickness.

  The semiconductor device of the present invention includes a semiconductor device in which the lower protective film is a silicon oxide film formed by an atmospheric pressure CVD method.

  According to this configuration, since the lower protective film is composed of the silicon oxide film formed by the atmospheric pressure CVD method, a dense film can be formed without using plasma.

  The semiconductor device of the present invention includes a semiconductor device in which the final protective film is a silicon nitride film formed by a plasma CVD method.

  According to such a configuration, as a result, since the protective film is formed of a two-layer film of a silicon oxide film and a silicon nitride film, a film having excellent protective characteristics can be obtained.

In the semiconductor device of the present invention, the wiring is formed so that the wiring covers the lower protective film from the through hole formed so as to penetrate the lower protective film, and the wiring is covered with the final protective film. Including.
According to such a configuration, since the lower protective film surely covers the through hole for contact, it is possible to prevent the occurrence of precipitates due to the ingress of moisture. And since the wiring terminal is coat | covered with the last protective film except the external connection part, it is in the state excellent also in terms of moisture resistance.

In the semiconductor device of the present invention, the through hole is formed in a lower layer of the first opening so that the through hole penetrates the reflow film, and a first opening that opens on an upper surface of the reflow film. A second opening having a smaller opening diameter than the opening, and the wiring includes a wiring formed so as to reach the upper surface of the lower protective film covering the reflow film from the first opening.
According to such a configuration, since the lower protective film has a shape that covers the through hole for contact more reliably, it is possible to prevent the occurrence of precipitates due to the ingress of moisture.

  The present invention also includes a step of forming a photoelectric conversion portion formed on a semiconductor substrate surface, a step of covering the semiconductor substrate surface including the photoelectric conversion portion with a silicon oxide film containing impurities, and the silicon oxide film The semiconductor device manufacturing method includes: a planarization step of planarizing the substrate by heat treatment to form a reflow film; and a step of forming a final protective film made of a silicon nitride film having an opening for contact on the surface of the semiconductor substrate. The method further includes, prior to the step of forming the final protective film, a step of forming a lower protective film by a non-plasma process at least on the reflow film on the photoelectric conversion portion.

  According to such a configuration, since the reflow film is covered with the lower protective film by a non-plasma process, it is grounded after the through hole is formed and before the plasma film is formed, but variation in the threshold voltage Vth due to plasma charging is prevented. However, it is possible to prevent impurities on the outermost surface of the reflow film from coming into contact with the atmosphere, and it is possible to prevent precipitation on the surface of the reflow film due to a reaction with the atmosphere. Here, it is desirable that the lower protective film is dense. Therefore, the black scratch defect at the time of light is prevented. It is desirable to use a material having a refractive index close to that of the reflow film. Thereby, reflection at the interface between the reflow film and the lower protective film is reduced, and a reduction in sensitivity can be prevented. Here, the final protective film refers to the uppermost protective film, and a silicon nitride film is usually used.

  In this way, by adding a step of forming a lower protective film by a non-plasma process, the lower protective film can suppress the deposition of phosphorus and boron from the reflow film without being charged by plasma. It is possible to suppress the light path shading and to suppress the occurrence of a black scratch defect at the time of light.

In the semiconductor device manufacturing method of the present invention, the step of forming the lower protective film includes a step of forming a silicon oxide film by an atmospheric pressure CVD method.
According to such a configuration, a dense and highly reliable lower protective film can be efficiently formed without causing charging.

In the semiconductor device manufacturing method of the present invention, the step of forming the final protective film includes a step of forming a silicon nitride film by a plasma CVD method.
According to this configuration, a dense and highly reliable final protective film can be efficiently formed. Since it can be formed at a low temperature, it can be formed while suppressing the liberation of impurities from the reflow film.

In the semiconductor device manufacturing method of the present invention, the step of forming the lower protective film includes a method in which the step of forming the lower protective film is performed after the step of heat-treating and planarizing the silicon oxide film.
With this configuration, the lower protective film is maintained without being affected by the heat for planarization, and the adhesion with the planarization film is improved, so that the reliability can be improved.

  Further, in the method of manufacturing a semiconductor device according to the present invention, the step of forming the wiring further includes, after the step of forming the light shielding film, performing isotropic etching on the region where the wiring is to be formed to a predetermined depth of the silicon oxide film. After the step of forming the first opening and the step of forming the lower protective film, a second opening penetrating the silicon oxide film is formed by anisotropic etching in a part of the first opening. Including a step, a step of filling the first and second openings with a conductive film, and a step of forming a final protective film after patterning the conductive film to form a wiring lead-out terminal.

  According to such a configuration, a through hole is formed so that the opening area is reduced on the lower layer side, a large opening on the upper layer side is covered with the lower protective film, and the upper layer is covered with a conductive film for contact, Further, since the upper layer is covered with the final protective film, the moisture resistance is reliable and the influence of plasma charging is greatly suppressed.

The semiconductor device manufacturing method of the present invention includes a method including a sintering process in which heat treatment is performed after the final protective film is formed.
According to such a configuration, even if plasma charging occurs, the charge can be released and the threshold voltage can be prevented from fluctuating.

In addition, the method for manufacturing a semiconductor device of the present invention includes a method in which the sintering step includes a step of performing a heat treatment in an inert gas atmosphere containing hydrogen.
According to such a configuration, the sintering can be performed efficiently.

  As described above, according to the present invention, it is possible to prevent the light path from being blocked due to the deposition of impurities on the surface of the reflow film while preventing variations in the threshold voltage due to plasma charging. It is possible to provide a highly reliable semiconductor device that is free from defects.

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
1 and 2 are schematic sectional views of the solid-state imaging device according to the first embodiment of the present invention. FIG. 1 shows an element portion, and FIG. 2 shows a peripheral contact portion. FIG. 3 is a schematic plan view. 1 is a cross-sectional view taken along line AA of FIG. 4 to 8 are process cross-sectional views. In the figure, for the sake of simplification, impurity regions and electrodes formed in the silicon substrate are omitted, and only an outline is shown.

  A plurality of photodiode regions (photoelectric conversion units) 30 are formed on the silicon substrate 1, and a charge transfer unit 40 for transferring signal charges detected in the photodiode region 30 is formed between the photodiode regions 30. The The element region formed in the silicon substrate 1 is omitted.

  Although not shown in FIG. 3, the charge transfer channel through which the signal charge transferred by the charge transfer electrode moves is formed in a direction crossing the direction in which the charge transfer unit 40 extends.

  In FIG. 3, the description of the interelectrode insulating film formed near the boundary between the photodiode region 30 and the charge transfer portion 40 is omitted.

  In this solid-state imaging device, as shown in FIG. 2, after the aluminum layer (wiring region) constituting the extraction region of the wiring 8 forms the light-shielding film 16, the isotropic etching is performed on the extraction region. After the first opening 6a is formed to a predetermined depth and the silicon oxide film 7 as a lower protective film is formed, the first opening 6a passes through the reflow film 5 by anisotropic etching in part of the first opening 6a. 2 is formed, a conductive film for forming the extraction region 8 is formed, and then a silicon nitride film as the final protective film 9 is formed by plasma CVD. To do.

  As a result, a through hole is formed so that the opening area is reduced on the lower layer side, a large opening on the upper layer side is covered with a lower protective film, and this upper layer is covered with a conductive film for contact, and this upper layer is further covered. Is covered with the final protective film, so that moisture resistance is ensured and grounded by the aluminum layer of the wiring 8, and the charge for the subsequent plasma process is reduced.

  Further, here, the charge transfer channel (not shown) through which the signal charge transferred by the charge transfer electrode 13 moves is formed to have a meandering shape in a direction intersecting with the direction in which the charge transfer electrode 13 extends. The A wiring 8 made of an aluminum layer is formed on the peripheral portion 50 of the silicon substrate 1 to constitute an external connection terminal.

  Further, as shown in FIG. 1, a plurality of photodiodes 30 are formed on the silicon substrate 1 to constitute a photoelectric conversion unit, and charge transfer electrodes 3 for transferring signal charges detected by the photodiodes are provided. The arranged charge transfer portions 40 are formed between the photodiodes 30 so as to have a meandering shape. In the present embodiment, the silicon nitride film 9, the reflow film 5, and the lower protective film 7 formed by the plasma CVD method, which is the final protective film covering other regions such as the peripheral portion, are removed on the surface of the photoelectric conversion portion. It is covered with a high refractive index film 12 made of a silicon nitride film. The reflow film 5 obtained by reflowing the BPSG film is covered with a lower protective film 7 made of a silicon oxide film formed by an atmospheric pressure CVD method.

  In this solid-state imaging device, since the lower protective film 4 is formed by atmospheric pressure CVD, charging due to plasma can be prevented and variation in threshold voltage can be suppressed. In addition, it is composed of a silicon oxide film that has a refractive index close to that of the reflow film, suppresses refraction at the interface, prevents the permeation of impurities from the reflow film, suppresses the precipitation of impurities, and attenuates the amount of light. None, the occurrence of black scratches at the time of light is suppressed.

  A photodiode 30, a charge transfer channel (not shown), a channel stop region, and a charge readout region (not shown) are formed in the silicon substrate 1, and an insulating film (hereinafter, referred to as an insulating film) is formed on the surface of the silicon substrate 1. 2) is formed. On the surface of the gate oxide film 2, an interelectrode insulating film made of a silicon oxide film and charge transfer electrodes 13a and 13b made of a polycrystalline silicon film are formed.

  A light shielding film (not shown) is provided above the solid-state imaging device except for the photodiode 30 portion, and a color filter (not shown) and a microlens (not shown) are further provided. Further, in the present embodiment, a so-called honeycomb structure solid-state imaging device is shown, but it goes without saying that the present invention can also be applied to a square lattice type solid-state imaging device.

  Next, the manufacturing process of this solid-state imaging device will be described with reference to FIGS. First, as shown in FIG. 1, the photodiode 30 and the charge transfer portion 40 are formed on the surface of the n-type silicon substrate 1 and the wiring pattern 3 is formed on the peripheral portion 50 by a normal method. This wiring pattern 3 is formed in the same process as any one of the charge transfer electrodes of the charge transfer portion.

Here, the gate oxide film has a three-layer structure formed of a silicon oxide film with a thickness of 15 nm to 35 nm, a silicon nitride film with a thickness of 50 nm, and a silicon oxide film with a thickness of 10 nm formed on the surface of the silicon substrate 1. It is what you make.
On the gate oxide film 2, charge transfer electrodes 13a and 13b made of a polycrystalline silicon film are formed.
Since these are formed by a normal method, description thereof is omitted in this embodiment.

As shown in FIG. 4A, a silicon oxide film having a thickness of 20 nm is formed on the surface of the silicon substrate 1 on which the photodiode 30, the charge transfer portion 40, and the peripheral portion 50 are formed by a normal method. A diffusion prevention film 4 made of is formed. The film formation conditions at this time were 400 ° C., pressure: 2.0 Torr, RF power (13.56 MHz: 0.3 kW), RF power (270 kW: 0.7 kW): TEOS: 1.5 ml / min, O ₂ : 10 SLM.

Then, as shown in FIG. 4B, a BPSG film having a thickness of 300 to 1000 nm to be the reflow film 5 is formed on this upper layer by the atmospheric pressure CVD method. The film forming conditions at this time are 410 ° C., the housing exhaust pressure is 10 Pa, the dispersion head exhaust pressure is 100 Pa, and the raw material gases are SiH ₄ : 2700 ccm, O ₂ : 2400 ccm, PH ₃ : 3300 ccm, B ₂ H ₆ : 2000 ccm. And Then, through a reflow process by heat treatment, the surface is flattened as shown in FIG. The reflow conditions at this time were set to 850 to 900 ° C., N ₂ : 10 SLM atmosphere, exhaust pressure: 5 to 15 mmH ₂ O, and processing time 30 to 60 minutes.

Thereafter, a resist pattern R1 is formed on the upper layer, and a first opening 6a is formed by isotropic etching to a predetermined depth of the reflow film 5 (FIG. 5D). Etching conditions at this time are a pressure of 1.4 Torr, an RF power of 350 W at room temperature, and an etching gas of NF ₃ : 22 sccm and He: 13 sccm. Thereafter, the resist pattern R1 is removed.

Then, a silicon oxide film having a thickness of 50 to 200 nm is formed as the lower protective film 7 on the upper layer by atmospheric pressure CVD (FIG. 5E). The film formation conditions at this time are 410 ° C., a housing exhaust pressure of 10 Pa, a dispersion head exhaust pressure of 100 Pa, and source gases of SiH ₄ : 900 ccm and O ₂ : 800 ccm.

Subsequently, a resist pattern R2 opening in a part of the first opening 6a is formed (FIG. 5F), and anisotropic etching is performed using the resist pattern R2 as a mask to form a second opening 6b (FIG. 6). (G)). The etching conditions at this time are a pressure of 800 mTorr and an RF power of 800 W at room temperature, and an etching gas of CHF ₃ : 40 sccm, CF ₄ : 40 sccm, and Ar: 800 sccm. Thereafter, the resist pattern R2 is removed.

  Then, as shown in FIG. 6H, an aluminum thin film having a thickness of 500 nm is formed by the PVD method. The film forming conditions are as follows: aluminum is used as a target, a film is formed at room temperature under a pressure of 2 mTorr, a target power is 3.0 kW, and argon is 150 sccm.

Thereafter, a silicon nitride film having a film thickness of 200 to 1500 nm is formed as the final protective film 9 by plasma CVD. This silicon nitride film becomes the final protective film. The film forming conditions at this time are 400 ° C., pressure: 2.0 Torr, RF power (13.56 MHz: 0.6 kW), RF power (270 kW: 0.1 kW): SiH ₄ : 100 sccm, NH ₃ : 500 sccm, N ₂ : 10 SLM.

Thereafter, sintering processing is performed. The sintering conditions are 380 ° C., N ₂ : 15 SLM, H ₂ : 1.5 SLM, exhaust pressure 5 to 15 mmH ₂ O, and processing time 30 to 60 minutes.

  Subsequently, a positive resist is applied to the upper layer so as to have a thickness of 0.5 to 2.0 μm.

  Then, exposure is performed using a desired mask by photolithography, development and water washing are performed to form a resist pattern R3 having a pattern width of 0.3 to several μm (FIG. 6 (i)).

Then, using this resist pattern R3 as a mask, the silicon nitride as the final protective film 9 is patterned as shown in FIG. The etching conditions at this time are a pressure of 50 Pa at room temperature, an RF power of 100 W, and an etching gas of CF ₄ : 200 sccm and O ₂ : 700 sccm. At this time, the final protective film 9 on the external connection region of the photoelectric conversion portion and the wiring is removed.

  Then, as shown in FIG. 7 (k), the resist pattern R3 is peeled and removed to form a solid-state imaging device as shown in FIGS.

  According to this method, the reflow film 5 made of the BPSG film is covered with the lower protective film formed by the atmospheric pressure CVD method and the final protective film made of silicon nitride formed by the plasma CVD method. There is no variation in threshold voltage, and no impurities are deposited on the surface. Therefore, it is possible to form a solid-state imaging device having good imaging characteristics without occurrence of a black defect.

  Furthermore, the yield can be improved without a significant increase in man-hours.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. In the first embodiment, the silicon oxide film as the lower protective film is formed in the lower layer of the wiring 8, but may be formed in the upper layer of the wiring 8.
Even in this case, it is possible to form a solid-state imaging device with good workability, no black scratch defect and excellent imaging characteristics.

  In the above embodiment, silicon nitride formed by the atmospheric pressure CVD method is used as the lower protective film, but a silicon nitride oxide film may be used instead.

  Although the solid-state imaging device has been described in the above embodiment, it is needless to say that the present invention is not limited to this and can be applied to a semiconductor device including a photoelectric conversion element such as a line sensor.

  As described above, according to the present invention, by forming the lower protective film by a non-plasma process, impurities are deposited on the surface of the reflow film while maintaining variations in threshold voltage by suppressing plasma charging. It is possible to provide a highly reliable photoelectric conversion element that can suppress light blockage of the light path and that there is no black scratch defect at the time of light, so it can be used for small digital cameras, image sensors, etc. The present invention can also be applied to a semiconductor device including the photoelectric conversion element.

1 is a schematic cross-sectional view of a solid-state imaging element according to Embodiment 1 of the present invention. 1 is a schematic cross-sectional view of a solid-state imaging element according to Embodiment 1 of the present invention. It is a plane schematic diagram of the solid-state image sensor of Embodiment 1 of the present invention. It is the schematic which shows the manufacturing process of the solid-state image sensor of Embodiment 1 of this invention. It is the schematic which shows the manufacturing process of the solid-state image sensor of Embodiment 1 of this invention. It is the schematic which shows the manufacturing process of the solid-state image sensor of Embodiment 1 of this invention. It is the schematic which shows the manufacturing process of the solid-state image sensor of Embodiment 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Gate oxide film 3 Polycrystalline silicon film 5 Reflow film 7 Lower protective film 9 Final protective film 30 Photodiode 40 Charge transfer electrode 50 Peripheral part

Claims (13)

Including a photoelectric conversion part formed on a semiconductor substrate surface;
The semiconductor substrate surface is covered with a reflow film and a protective film formed in an upper layer of the reflow film, and is a semiconductor device comprising a wiring opening in a part of the protective film,
The protective film includes a final protective film and a lower protective film formed under the final protective film,
The surface of the reflow film is covered with a lower protective film made of an insulating film formed by a non-plasma process,
The wiring is a semiconductor device formed in an upper layer of the lower protective film. The semiconductor device according to claim 1,
The semiconductor device in which the lower protective film is a silicon oxide film formed by an atmospheric pressure CVD method. The semiconductor device according to claim 2,
The semiconductor device, wherein the final protective film is a silicon nitride film formed by a plasma CVD method. A semiconductor device according to any one of claims 1 to 3,
The wiring is formed so as to cover the lower protective film from the through hole formed so as to penetrate the lower protective film,
A semiconductor device in which the wiring is covered with a final protective film. The semiconductor device according to claim 4,
The through-hole is formed in a lower layer of the first opening so as to penetrate the reflow film, and a first opening having an opening diameter smaller than that of the first opening. Two openings,
The semiconductor device is formed so that the wiring reaches the upper surface of the lower protective film covering the reflow film from the first opening. Forming a photoelectric conversion portion formed on the surface of the semiconductor substrate;
Covering the surface of the semiconductor substrate including the photoelectric conversion part with a silicon oxide film containing impurities;
Planarizing the silicon oxide film by heat treatment to form a reflow film; and
Forming a final protective film made of a silicon nitride film having an opening for contact on the surface of the semiconductor substrate.
Prior to the step of forming the final protective film, a method for manufacturing a semiconductor device including a step of forming a lower protective film on at least an upper layer of the reflow film on the photoelectric conversion portion by a non-plasma process. A method of manufacturing a semiconductor device according to claim 6,
The step of forming the lower protective film includes a step of forming a silicon oxide film by an atmospheric pressure CVD method. A method of manufacturing a semiconductor device according to claim 6 or 7,
The method of forming a final protective film includes a step of forming a silicon nitride film by a plasma CVD method. A method for manufacturing a semiconductor device according to claim 6, wherein:
A method of manufacturing a semiconductor device including a step of forming a light-shielding film formed to have an opening in the photoelectric conversion portion prior to the formation of the final protective film. A method of manufacturing a semiconductor device according to claim 9,
The step of forming the lower protective film is a method for manufacturing a semiconductor device, which is executed after a step of heat-treating and planarizing the reflow film. It is a manufacturing method of the semiconductor device according to claim 9 or 10,
Furthermore, the process of forming the wiring
After the step of forming the light shielding film,
Forming a first opening to a predetermined depth of the reflow film by isotropic etching in a region for forming a wiring;
After the step of forming a lower protective film, forming a second opening penetrating the reflow film by anisotropic etching in a part of the first opening;
Filling the first and second openings with a conductive film;
A method of manufacturing a semiconductor device, comprising: forming a final protective film after patterning the conductive film to form a wiring. A method for manufacturing a semiconductor device according to claim 11, comprising:
A method of manufacturing a semiconductor device, comprising a sintering step of performing a heat treatment after forming the final protective film. A method of manufacturing a semiconductor device according to claim 12,
The method of manufacturing a semiconductor device, wherein the sintering step is a step of performing a heat treatment in an inert gas atmosphere containing hydrogen.

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