JP2007201161A - Solid state imaging element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid state imaging element including a charge transfer electrode with high precision in dimension even in performing refinement. <P>SOLUTION: The solid state imaging element includes a photoelectric converter and a charge transfer having the charge transfer electrode to transfer a charge which is generated in the photoelectric converter. A charge transfer electrode forming process in a solid state imaging element manufacturing method comprises a process for forming a first layer conductive film where at least the surface is composed of refractory metal or refractory metal silicide, on the surface of a semiconductor substrate via a gate oxide film, patterning the first layer conductive film by photolithography, and forming a first layer electrode; a process for forming an inter-electrode insulating film around the first layer electrode; a process for forming a second layer conductive film on the surface of the semiconductor substrate with the first layer electrode formed thereon; and a process for forming a second layer electrode by making the surface flat by defining the refractory metal or refractory metal silicide as a removal suppressing layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device manufacturing method and a solid-state imaging device, and more particularly to pattern formation of a first layer electrode.

  A solid-state imaging device using a CCD 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, the demand for higher resolution and higher sensitivity has been increasing in solid-state imaging devices, and the number of imaging pixels has been increasing to more than gigapixels. Improvements in accuracy and accuracy have become extremely important, and the patterning accuracy of charge transfer electrodes has become extremely important.

  By the way, in order to improve the flatness, a structure in which the charge transfer portion has a single-layer electrode structure by chemical mechanical polishing (CMP) has been proposed. In a solid-state imaging device using a single-layer structure charge transfer electrode, for example, a polycrystalline silicon layer is used as the charge transfer electrode, and the surface of the first layer electrode obtained by forming and patterning the first layer conductive film is oxidized. Then, an interelectrode insulating film is formed, and a polycrystalline silicon layer serving as a second layer charge transfer electrode is deposited thereon, and the second layer electrode is formed by planarizing the surface by CMP to transfer the charge. A single-layered electrode is implemented (for example, Patent Document 1).

Furthermore, in such a situation, in order to obtain high resolution without increasing the chip size, it is necessary to reduce the area per unit pixel and achieve high integration. On the other hand, if the area of the photodiode constituting the photoelectric conversion unit is reduced, the sensitivity is lowered, so the area of the photodiode region must be ensured.
Therefore, various studies have been made to reduce the size of the chip while securing the area occupied by the photodiode region by reducing the wiring area ratio by reducing the wiring area of the charge transfer portion and the peripheral circuit. .

  In such a situation, maintaining the flatness of the interlayer insulating film between the wiring layers is an important technical issue in order to realize high integration by miniaturization of the wiring. In order to improve the flatness, a structure in which the charge transfer portion has a single-layer electrode structure has been proposed (for example, Patent Document 1).

  By the way, in a conventional solid-state imaging device using a charge transfer electrode having a single layer structure, a polycrystalline silicon or amorphous silicon layer is used as the charge transfer electrode, and the first layer conductive film is formed after the first layer conductive film is formed. Oxidize the pattern surface of the film, deposit a polycrystalline silicon or amorphous silicon layer to be the second transfer electrode, apply resist, and etch the entire surface by resist etch back method to make the electrode a single layer We are carrying out.

  For example, conventionally, when manufacturing the above-described solid-state imaging device, the charge transfer portion of this single-layer electrode structure is formed by using, for example, the steps shown in FIGS. First, a silicon oxide film 2a having a film thickness of 15 to 35 nm, a silicon nitride film 2b having a film thickness of 50 nm, and a silicon oxide film 2c having a film thickness of 10 nm are formed on the surface of the n-type silicon substrate 1 to form a gate oxide having a three-layer structure. A film 2 is formed.

Subsequently, a first layer doped amorphous silicon film 3a is formed on the gate oxide film 2, and a silicon oxide film 14 and a silicon nitride film 15 are formed by CVD (FIG. 7A).
Subsequently, a resist is applied to the upper layer.

  Then, as shown in FIG. 7B, exposure is performed using a desired mask by photolithography, development and washing with water are performed to form a resist pattern R1.

Thereafter, as shown in FIG. 7C, the resist pattern R1 is used as a mask to etch the silicon oxide film 14 and the silicon nitride film 15 to form a mask pattern for patterning the first layer electrode.
Then, the resist pattern is peeled and removed by ashing (FIG. 7D), and the first layer doped amorphous silicon film 3a is selectively used by using the mask pattern as a mask and the silicon nitride film 2b of the gate oxide film 2 as an etching stopper. Etching is removed to form a first layer electrode (FIG. 8A).

Subsequently, the interelectrode insulating film 4 is formed on the side wall surface of the pattern of the first layer electrode by thermal oxidation (FIG. 8B), and the second layer doped amorphous silicon film 3b is formed thereon (FIG. 8B). 8 (c)).
After that, a resist is applied to the entire surface, and the second layer doped amorphous silicon film 3b is flattened by resist etch back (FIG. 8D).

Thereafter, using the resist pattern as a mask, the second layer doped amorphous silicon film 3b on the photodiode region 30 is selectively removed by etching.
In this way, the second layer electrode made of the second layer doped amorphous silicon film 3b is formed, and the charge transfer electrode having a flat single layer electrode structure is formed.

  In the case of this method, patterning of the first layer conductive film needs to be extremely accurate. However, the variation in the thickness of the silicon nitride film formed on the upper layer of the silicon oxide film, the increase in the thickness due to these films, and the irregular reflection due to the variation in the thickness, the pattern accuracy in the photolithography process is reduced. It was not obtained sufficiently, resulting in poor process stability and causing dimensional variations.

  In the case of this structure, the silicon oxide film obtained by thermally oxidizing the surface of the first layer electrode is interposed between the first layer electrode and the second layer electrode and serves as an interelectrode insulating film. Therefore, the film quality, film thickness and shape are important. In addition, since this silicon oxide film oxidizes and erodes the first layer conductive film constituting the first layer electrode, the uniformity of oxidation depends on the uniformity of the silicon oxide film and the shape of the first layer electrode. It is extremely important from the two points of maintenance.

  Further, not only in resist etch-back, but also in the case where planarization is performed by chemical mechanical polishing (CMP), the thickness of the second layer doped amorphous silicon film (second layer conductive film) is also similar. Variation may occur.

  Such variations in film thickness cause variations in wiring resistance and deterioration in transfer efficiency. In addition, the film thickness of various films such as flattening films, microlenses, and color filters above the charge transfer electrode may become non-uniform and increase in shape variation, resulting in shading, sensitivity variation, and deterioration of smear due to stray light. There is also a problem that occurs.

  For this reason, it has been difficult for the method as described above to cope with further improvement in sensitivity.

JP 11-26743 A

As described above, in the conventional solid-state imaging device, with further miniaturization, the second layer conductive film is flattened, and a silicon oxide film is used as a removal suppression layer (stopper layer) for flattening when a single-layer electrode is formed. Since a two-layer film of silicon nitride film and silicon nitride film is used, there is a problem in that a decrease in pattern accuracy due to the film thickness of the two-layer film itself cannot be ignored.
Furthermore, after forming the first layer electrode constituting the first layer conductive film, oxidation is performed to form a silicon oxide film that becomes the interelectrode insulating film 4, but the oxidation does not progress uniformly, It has been difficult to form the first layer electrode so that it is pointed or rounded and the pattern edge is vertical.
As a result, the distance between the electrodes increases, leading to deterioration in transfer efficiency and an increase in depletion voltage, and a part where the distance between the electrodes is narrowed, resulting in an interlayer breakdown voltage failure. It was the cause of the decline.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a solid-state imaging device including a charge transfer electrode with high dimensional accuracy even when miniaturized.

Accordingly, the present invention provides a method for manufacturing a solid-state imaging device, comprising: a photoelectric conversion unit; and a charge transfer unit including a charge transfer electrode that transfers charges generated in the photoelectric conversion unit. A step of forming a first layer conductive film having at least a surface made of a refractory metal or a refractory metal silicide on a surface of a semiconductor substrate through a gate oxide film; Forming a first layer electrode; forming an interelectrode insulating film around the first layer electrode; and forming a second layer conductive film on the surface of the semiconductor substrate on which the first layer electrode is formed. And a step of planarizing the surface using the refractory metal or the refractory metal silicide as a removal suppressing layer to form a second layer electrode.
According to this configuration, in the photolithography process for patterning the first layer electrode, the film itself to be patterned can be thinned, so that it is possible to measure extremely high accuracy. Moreover, since it can be used as it is as a removal suppression layer in the planarization step performed for forming the second layer electrode, the pattern accuracy can be improved. That is, the two-layer film of the silicon oxide film and the silicon nitride film, which has been used as a mask or as a removal suppression layer prior to patterning the first layer electrode, is likely to have a variation in film thickness. Although this caused a reduction in dimensional accuracy, the silicon oxide film and the silicon nitride film are no longer necessary, and the metal film or the metal silicide film acts as a removal suppressing layer as it is, so that the pattern accuracy can be improved.

According to the present invention, in the method of manufacturing a solid-state imaging device, the step of forming the interelectrode insulating film includes a step of forming a radical oxide film by low-temperature plasma so as to cover the first layer electrode.
According to this configuration, a low-temperature formation and a good quality radical oxide film is formed on the surface of the first layer electrode, and there is no change in the shape of the first layer electrode, so that an electrode with high dimensional accuracy can be formed. Become.

In the method for manufacturing a solid-state imaging device according to the present invention, the step of forming the second layer electrode includes a step of planarizing by CMP using the surface of the first layer electrode as a removal suppressing layer.
According to this configuration, a solid-state imaging device with good surface flatness is formed by CMP.

In the method for manufacturing a solid-state imaging device according to the present invention, the step of forming the second layer electrode includes a step of planarizing by performing resist etch back using the surface of the first layer electrode as a removal suppressing layer. .
According to this configuration, a solid-state imaging device with good surface flatness is formed by resist etchback.

According to the present invention, in the method of manufacturing a solid-state imaging device, the step of forming the first layer electrode includes a step of forming a silicon-based conductive film and a step of forming a refractory metal film on the upper layer. .
According to this configuration, it is possible to form the first layer electrode with low resistance and high reliability.

According to the present invention, in the method of manufacturing a solid-state imaging device, the step of forming the first layer electrode includes a step of forming a refractory metal film made of a tungsten film.
According to this configuration, the resistance is low and the light shielding property is high.

  According to the present invention, in the method for manufacturing a solid-state imaging device, the step of forming the first layer electrode includes a step of forming a refractory metal film made of a molybdenum film.

According to the present invention, in the method of manufacturing a solid-state imaging device, the step of forming the first layer electrode includes a step of forming a silicon-based conductive film and a step of forming the refractory metal film on the upper layer. Including.
When the first layer electrode is formed of a silicon conductive film such as a polycrystalline silicon layer, it is difficult to reduce the resistance value. However, according to this configuration, a metal film can be easily laminated on the polycrystalline silicon film. It is possible to form a charge transfer electrode with low resistance and high reliability.

According to the present invention, in the method for manufacturing a solid-state imaging device, the step of forming the second layer electrode is a step of forming a silicon-based conductive film. Since a silicon-based conductive film such as a film is used as the second layer electrode, it is possible to form a charge transfer electrode having a single layer structure with good workability and high surface flatness. The second layer electrode was also flattened by CMP or resist etchback, and then slightly over-etched to remove the surface of the second layer electrode, such as tungsten or molybdenum, and preferably used for the first layer electrode. A metal film may be formed. As a result, as with the first layer electrode, the resistance can be reduced.

Further, the present invention provides a solid-state imaging device including a photoelectric conversion unit and a charge transfer unit including a charge transfer electrode that transfers charges generated in the photoelectric conversion unit, wherein the charge transfer electrode has at least a surface. A first layer electrode composed of a refractory metal or a refractory metal silicide, a second layer electrode formed through a radical oxide film formed by low temperature plasma so as to cover the first layer electrode, and It is provided with.
According to this configuration, since the first layer electrode is thin and can be used as it is as the removal suppressing layer in the planarization step performed for forming the second layer electrode, the pattern accuracy of the first layer electrode is improved. It becomes possible. That is, prior to the patterning of the first layer electrode, the two-layer film of the silicon oxide film and the silicon nitride film used as a mask or as a removal suppressing layer is likely to cause a variation in film thickness. Although this has been the cause of the decrease, the silicon oxide film and the silicon nitride film are not required, and the metal film or the metal silicide film acts as a removal suppressing layer as it is, so that the pattern accuracy can be improved.

According to the present invention, in the solid-state imaging device, the second layer electrode includes a silicon-based conductive film.
According to this configuration, when the second layer electrode is formed, the metal or metal silicide film constituting the first layer electrode is planarized as a removal suppressing layer, so that a single-layer structure with a high dimensional accuracy can be achieved extremely efficiently. Charge transfer electrodes can be formed.

  In the solid-state imaging device according to the present invention, the refractory metal is tungsten. According to this configuration, it is effective as a removal suppressing layer, has high light shielding properties and low specific resistance, and is effective as a first layer electrode.

In the solid-state imaging device according to the present invention, the refractory metal is molybdenum.
According to this configuration, it is effective as a removal suppressing layer, has high light shielding properties and low specific resistance, and is effective as a first layer electrode.

  In the solid-state imaging device according to the present invention, the refractory metal is nickel or cobalt.

  The metal film may be a tungsten film formed by a low pressure CVD method. According to such a configuration, it is possible to form a tungsten film with good step coverage by a low pressure CVD method, and at the same time, it is possible to have a light shielding effect.

Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
As shown in FIG. 1 which is a cross-sectional view of the main part of the charge transfer unit and in FIG. 2, the solid-state imaging device includes a photoelectric conversion unit, A solid-state imaging device including a charge transfer unit including a charge transfer electrode for transferring a charge generated in the conversion unit, wherein the charge transfer electrode is formed in a first layer polycrystalline silicon film 3a and an upper layer thereof A first layer electrode composed of the tungsten film 3M formed, and a second layer polycrystalline silicon film 3b formed through a radical oxide film 4 formed of low temperature plasma so as to cover the periphery of the first layer electrode. And the second layer electrode.

At the time of manufacturing, the charge transfer electrode forming step forms a first layer polycrystalline silicon film 3a on the surface of the silicon substrate 1 via the gate oxide film 2 and a tungsten film 3M as an upper layer thereof, which is formed by photolithography. After patterning to form a first layer electrode, radical oxidation by low-temperature plasma is performed around the first layer electrode to form an interelectrode insulating film made of a radical oxide film, and a second layer polycrystalline silicon is further formed thereon. The step of forming a film and the tungsten film 3M of the first layer electrode are used as a removal suppressing layer to planarize the surface and form the second layer electrode.
The surface of the tungsten film 3M and the surface of the polycrystalline silicon film 3b as the second layer electrode are substantially the same.

  That is, as shown in FIG. 1 and FIG. 2 which are a schematic cross-sectional view and a plan view of a solid-state imaging device (FIG. 1 is a cross-sectional view taken along the line AA in FIG. The photoelectric conversion section and the charge transfer section provided are formed, and the upper layer thereof is covered with an insulating film.

  The charge transfer unit 40 is formed in the upper layer of a plurality of vertical charge transfer channels 33 formed in the column direction of the surface portion of the silicon substrate 1 corresponding to each of the plurality of photodiode columns, and the vertical charge transfer channel 33. The charge transfer electrode 3 and a charge read region 34 for reading the charge generated in the photodiode 30 to the vertical charge transfer channel 33 are included. The charge transfer electrode 3 has a meandering shape extending in the row direction as a whole between a plurality of photodiode rows composed of a plurality of photodiodes 30 arranged in the row direction. Further, the vertical charge transfer channel 33 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.

  As shown in FIG. 1, a p-well layer is formed on the surface of the silicon substrate 1, an n-region for forming a pn junction is formed in the p-well layer, and a p-region is formed on the surface. The signal charge generated by the photodiode 30 is accumulated in the n region.

  A vertical charge transfer channel 33 composed of an n region is formed adjacent to the photodiode 30. A charge readout region 34 is formed in the p-well layer between the n region and the vertical charge transfer channel 33.

  A charge transfer electrode is formed on the charge readout region 34 and the vertical charge transfer channel 33 via the gate oxide film 2. An interelectrode insulating film 4 is formed between the electrodes. A channel stop 32 made of a p + region is provided on the right side of the vertical transfer channel 33 so as to be separated from the adjacent photodiode 30.

  A radical oxide film 4, a silicon oxide film 5, an antireflection film 6, a light shielding film 8, an insulating film 9 made of BPSG (borophosphosilicate glass), and an intermediate film 70 are formed on the charge transfer electrode 3. Above these, a color filter 50 (red filter 50R, green filter 50G, blue filter: not shown), a planarizing film 61 and a microlens 60 made of a transparent resin or the like are provided.

Next, the manufacturing process of this solid-state image sensor will be described.
First, as shown in FIG. 3A, a 15 nm thick silicon oxide film, a 50 nm thick silicon nitride film, and a 10 nm thick silicon oxide film are formed on the surface of the n-type silicon substrate 1. A gate oxide film 2 having a three-layer structure is formed. Subsequently, a highly doped polycrystalline silicon film 3a having a thickness of 0.5 μm is formed on the gate oxide film 2 by the CVD method. Further, a tungsten film having a thickness of about 0.2 μm is formed by the CVD method.
Subsequently, a resist is applied to the upper layer so as to have a thickness of 0.8 to 1.4 μm.

  Then, exposure is performed by photolithography using a desired mask, development, and water washing are performed to form a resist pattern R1 as shown in FIG.

  Thereafter, as shown in FIG. 3C, after the tungsten film 3M is selectively removed by reactive ion etching using the resist pattern as a mask, the polycrystal is formed using the silicon nitride film 2b of the gate oxide film 2 as an etching stopper. After selectively removing the silicon film 3a by etching, the resist pattern is peeled off. Here, it is desirable to use an etching apparatus such as ECR (Electron Cyclotoron Resonance) or ICP (Inductively Coupled Plasma).

  Then, as shown in FIG. 4A, an interelectrode insulating film 4 made of a silicon oxide film having a thickness of 30 nm is formed by radical oxidation using low-temperature plasma.

Then, as shown in FIG. 4B, a highly doped polycrystalline silicon film 3b having a film thickness of 0.4 to 1.4 [mu] m is formed by the CVD method.
Then, as shown in FIG. 4C, the surface of the substrate is polished and chemically etched by CMP until the upper surface of the interelectrode insulating film 4 is exposed. At this time, even if the interelectrode insulating film 4 is removed, CMP (etching) stops because the tungsten film 3M acts as a removal suppressing layer.
In this way, the second layer electrodes made of the second layer polycrystalline silicon film are individually separated, and the silicon oxide film 5 is formed on the upper layer by the low pressure CVD method.

  Finally, after forming the antireflection film 6, the light shielding film 7, the interlayer insulating film 10, and the flattening film 11, the color filter layer 50 is formed, the flattening film 70 is applied, and the lens 60 is formed. A solid-state imaging device as shown in FIG. 1 can be formed.

  According to this configuration, in the photolithography process for patterning the first layer electrode, the patterning target is a two-layer film of a polycrystalline silicon film and a tungsten film, and the film to be patterned itself is made thin. Therefore, the pattern accuracy can be improved. Further, since this tungsten film can be used as it is as a removal suppressing layer in the planarization step performed for forming the second layer electrode, the pattern accuracy can be improved. That is, the two-layer film of the silicon oxide film and the silicon nitride film, which has been used as a mask or as a removal suppression layer prior to patterning the first layer electrode, is likely to have a variation in film thickness. Although this caused a reduction in dimensional accuracy, the silicon oxide film and the silicon nitride film are no longer necessary, and the tungsten film acts as a removal suppressing layer as it is, so that the pattern accuracy can be improved.

  Furthermore, since the interelectrode insulating film 4 is composed of a radical oxide film, it can be formed at a low temperature, and a film with good film quality can be formed. Is possible. Furthermore, since it can be formed by low-temperature oxidation, the edge of the polycrystalline silicon film can be prevented from being rounded, and the polycrystalline silicon film for forming the second layer electrode remains at the edge of the first layer electrode. There is no risk of inviting.

  In the first embodiment, the second layer electrode is formed of a polycrystalline silicon film. However, in order to reduce the resistance of the charge transfer electrode, a metal film is formed on the surface of the conductive film. A charge transfer electrode having a layer structure may be formed.

Furthermore, although the first layer electrode is composed of a two-layer film of a polycrystalline silicon film and a tungsten film, tungsten silicide may be formed by heat treatment. Further, both the first layer electrode and the second layer electrode may use an amorphous silicon film instead of the polycrystalline silicon film.
In addition, the refractory metal film is not limited to tungsten, and a molybdenum film, a cobalt film, a nickel film, or the like may be used.

  In addition, in the above embodiment, the second layer electrode is planarized by CMP, but resist etchback may be used.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.
In the first embodiment, as shown in FIG. 5, the second layer electrode is composed of a single layer of a polycrystalline silicon film. However, in this embodiment, both the first layer electrode and the second layer electrode are multi-layered. It is characterized by comprising a two-layer film of crystalline silicon films 3a and 3b and tungsten silicide 3T. Others are formed in the same manner as in the first embodiment.

  At the time of manufacture, as shown in FIG. 4C in the first embodiment, the second layer electrode is generally planarized by etch back, and then the etching conditions are changed to form radicals as interelectrode insulating films. The surface of the polycrystalline silicon film 3b is further over-etched using etching conditions that give selectivity to the oxide film 4 (FIG. 6A). Then, a tungsten film is formed on the upper layer so as to be lower than the surface of the first layer electrode (FIG. 6B), and after silicidation (FIG. 6C), it remains without being silicidized. The tungsten film on the radical oxide film 4 on the first layer electrode is removed (FIG. 6D).

  Thus, as shown in FIG. 5, the charge transfer electrode having a single-layer electrode structure in which both the first layer electrode and the second layer electrode are constituted by the two-layer films of the polycrystalline silicon films 3a and 3b and the tungsten silicide 3T. It is formed.

  In addition to tungsten, the metal film may be tantalum, titanium, molybdenum, cobalt, a silicide thereof, or aluminum.

  As described above, according to the present invention, it is possible to reduce the gap beyond the design rule, and it is possible to obtain a solid-state imaging device having a charge transfer electrode with high efficiency and high reliability even in miniaturization. Therefore, it is effective for application to small devices such as portable terminals.

It is sectional drawing which shows the solid-state image sensor of the 1st Embodiment of this invention. It is a top view which shows the solid-state image sensor of the 1st Embodiment of this invention. 3A to 3C are diagrams showing a manufacturing process of the solid-state imaging device according to the first embodiment of the present invention. 4A to 4C are diagrams showing a manufacturing process of the solid-state imaging device according to the first embodiment of the present invention. It is a top view which shows the solid-state image sensor of the 2nd Embodiment of this invention. FIGS. 6A to 6D are diagrams showing manufacturing steps of the solid-state imaging device according to the second embodiment of the present invention. 7A to 7D are diagrams showing a manufacturing process of a conventional solid-state imaging device. 8A to 8D are diagrams showing a manufacturing process of a conventional solid-state imaging device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Gate oxide film 4 Interelectrode insulating film 3a 1st layer polycrystalline silicon film 3b 2nd layer polycrystalline silicon film 3M Tungsten film 3T Tungsten silicide film 5 Silicon oxide film 6 Antireflection film 8 Light shielding film 30 Photodiode part 40 charge transfer unit 50 color filter 60 micro lens 70 intermediate layer

Claims (14)

In a method for manufacturing a solid-state imaging device, comprising: a photoelectric conversion unit; and a charge transfer unit including a charge transfer electrode that transfers charges generated in the photoelectric conversion unit.
The step of forming the charge transfer electrode comprises:
A first layer conductive film having at least a surface composed of a refractory metal or a refractory metal silicide is formed on the surface of the semiconductor substrate via a gate oxide film, and this is patterned by photolithography to form a first layer electrode Forming a step;
Forming an interelectrode insulating film around the first layer electrode;
Forming a second layer conductive film on the surface of the semiconductor substrate on which the first layer electrode is formed;
And a step of flattening the surface using the refractory metal or the refractory metal silicide as a removal suppressing layer to form a second layer electrode. It is a manufacturing method of the solid-state image sensing device according to claim 1,
The step of forming the interelectrode insulating film includes a step of forming a radical oxide film by low-temperature plasma so as to cover the first layer electrode. It is a manufacturing method of the solid-state image sensing device according to claim 1,
The step of forming the second layer electrode includes a step of planarizing by CMP using the surface of the first layer electrode as a removal suppressing layer. It is a manufacturing method of the solid-state image sensing device according to claim 1,
The step of forming the second layer electrode includes a step of flattening by performing resist etchback using the surface of the first layer electrode as a removal suppressing layer. It is a manufacturing method of the solid-state image sensing device according to any one of claims 1 to 4,
The step of forming the first layer electrode includes a step of forming a silicon-based conductive film and a step of forming the refractory metal film as an upper layer thereof. A method for manufacturing a solid-state imaging device according to any one of claims 1 to 5,
The step of forming the first layer electrode is a method for manufacturing a solid-state imaging device, including a step of forming a refractory metal film made of a tungsten film. A method for manufacturing a solid-state imaging device according to any one of claims 1 to 5,
The step of forming the first layer electrode includes a step of forming a refractory metal film made of a molybdenum film. A method for manufacturing a solid-state imaging device according to any one of claims 1 to 7,
The step of forming the second layer electrode is a method of manufacturing a solid-state imaging device, which is a step of forming a silicon-based conductive film. In a solid-state imaging device including a photoelectric conversion unit, and a charge transfer unit including a charge transfer electrode that transfers charges generated in the photoelectric conversion unit,
The charge transfer electrode is
A first layer electrode having at least a surface made of a refractory metal or a refractory metal silicide;
A solid-state imaging device comprising: a second layer electrode formed through a radical oxide film formed of low-temperature plasma formed so as to cover the periphery of the first layer electrode. The solid-state imaging device according to claim 9,
The second layer electrode is a solid-state imaging device formed of a silicon-based conductive film. The solid-state imaging device according to claim 9 or 10,
The first layer electrode is a solid-state imaging device including a silicon-based conductive film and a refractory metal or a refractory metal silicide film formed thereon. The solid-state imaging device according to any one of claims 9 to 11,
The solid-state imaging device, wherein the refractory metal is tungsten. The solid-state imaging device according to any one of claims 9 to 11,
The solid-state imaging device, wherein the refractory metal is molybdenum. The solid-state imaging device according to any one of claims 9 to 11,
The solid-state imaging device, wherein the refractory metal is nickel or cobalt.

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