JP2007012677A - Solid state image sensor and its fabrication process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid state image sensor exhibiting high sensitivity and high reliability even in case of high degree scaling-down. <P>SOLUTION: In a solid state image sensor comprising a photoelectric converting section, and a charge transfer section equipped with an electrode for transferring charges generated at the photoelectric converting section, the charge transfer electrode is composed of a metal material film and the light receiving region of the photoelectric converting section is defined at the outer end of the charge transfer electrode. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device and a manufacturing method thereof, and more particularly to a manufacturing method of a solid-state imaging device having a structure capable of withstanding the miniaturization by reducing the resistance of a charge transfer 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, demands for higher resolution and higher sensitivity have been increasing in solid-state imaging devices, and the number of imaging pixels has been increasing to more than gigapixels. Under such circumstances, 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. As miniaturization progresses, it is becoming difficult to maintain sensitivity and smear. In particular, in order to maintain sensitivity, it is desirable to make the opening area of the light shielding film as wide as possible. However, this is a trade-off with the width of the transfer path, and the S / N ratio can be improved even if the charge detection sensitivity is increased. There was a problem that I could not.

  As described above, if the area of the photodiode constituting the photoelectric conversion unit is reduced, the sensitivity is lowered. Therefore, 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 of the charge transfer portion and the peripheral circuit portion and reducing the area ratio of the wiring. Yes.

  Under these circumstances, 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. Furthermore, a substrate (silicon substrate) on which a solid-state image sensor is built is mounted by laminating filters and lenses. For this reason, the positional accuracy between the lens and the photoelectric conversion unit is important, and the distance, that is, the distance in the height direction, is a big problem in terms of positional accuracy in the manufacturing process and sensitivity (photoelectric conversion efficiency) in use. .

  In order to improve the flatness, a structure in which the charge transfer portion has a single-layer electrode structure has been proposed. In the CCD, the gap between the electrodes is an important factor for determining the transfer efficiency, and how small the gap between the electrodes is important. However, in the formation of an electrode pattern by a normal photolithography technique, the limit is 0.2 μm, and it is difficult to form an electrode pattern smaller than this. Further, when the distance between the electrodes is miniaturized, the aspect ratio must be increased, and it is extremely difficult to embed an insulating film in the gap between the electrodes that is fine and has a large aspect ratio.

  For this reason, the miniaturization of the gap between the electrodes is extremely serious, and when sufficient pattern accuracy cannot be obtained, sensitivity variations, smear deterioration due to stray light, etc. are caused, and improvement of pattern accuracy is a serious problem. In addition, miniaturization of the peripheral circuit portion is also demanded.

  In a conventional solid-state imaging device using a charge transfer electrode having a single-layer structure, a pattern of a first-layer conductive film is formed in order to achieve a finer resolution beyond the resolution of photolithography when a gap between electrodes is miniaturized. Thereafter, an interelectrode insulating film is formed, and a second-layer conductive film is laminated thereon, and then planarized by resist etchback or CMP (Chemical Mechanical Polishing) method has been proposed (patent) Reference 1).

JP 2004-179608 A

  As described above, in the conventional solid-state imaging device, with miniaturization, it is necessary to maximize the photoelectric conversion unit in order to reduce smear and maintain high sensitivity, but it is necessary to increase the opening area of the light shielding film. In addition, it is extremely difficult to achieve both the maximum transfer path width and the SN ratio cannot be improved even if the charge detection sensitivity is improved.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solid-state imaging device having high sensitivity and high reliability even at high miniaturization.

Therefore, the solid-state imaging device according to the present invention is 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. And a light receiving region of the photoelectric conversion unit is defined by an outer end of the charge transfer electrode.
According to this configuration, a low-resistance charge transfer electrode can be obtained, and the charge transfer electrode itself has a light shielding property, so that a light shielding film becomes unnecessary. Accordingly, the photoelectric transfer region is defined in a self-aligned manner with the edge of the charge transfer electrode while realizing reliable light shielding by the charge transfer electrode formed of a metal material, and the photoelectric conversion region is expanded to the maximum. It becomes possible.

In the solid-state imaging device of the present invention, the metal material film includes a single layer structure.
According to this structure, manufacture is easy.

In the solid-state imaging device of the present invention, the metal material film has a laminated structure.
According to this configuration, the light shielding property can be further improved, and the material can be easily selected.

In the solid-state imaging device of the present invention, the metal material film contains tungsten.
According to this configuration, it is possible to form a charge transfer electrode having a high light shielding property and a low resistance.

In the solid-state imaging device of the present invention, the metal material film includes a laminated structure of a titanium nitride layer and a tungsten layer.
According to this configuration, it is possible to obtain a charge transfer electrode having good adhesion to the base layer and high light shielding properties.

  In the solid-state imaging device according to the present invention, the charge transfer electrode is a single-layer electrode including a first electrode and a second electrode formed through an interelectrode insulating film that covers a side wall of the first electrode. The inter-electrode insulating film includes a structure having a two-layer structure of a radical oxide film formed by low-temperature plasma and a CVD film.

  According to this configuration, in addition to the above effects, a fine and high-quality insulating film can be formed even if the gap between the electrodes is reduced along with the miniaturization.

In the solid-state imaging device of the present invention, the CVD film is a silicon oxide film.
According to this configuration, it is possible to form a charge transfer electrode having a high light shielding property and a low resistance.

In the solid-state imaging device of the present invention, the CVD film is a silicon nitride film.
According to this configuration, it is possible to form a charge transfer electrode having a high light shielding property and a low resistance.

In addition, the solid-state imaging device of the present invention includes a solid-state imaging device in which a photoelectric conversion unit is disposed on the periphery of the charge transfer electrode without a light shielding film.
According to this configuration, the photoelectric conversion portion can be maximized, and a charge transfer electrode having a high light shielding property and a low resistance can be formed.

In addition, the solid-state imaging device of the present invention includes a solid-state imaging device in which an in-layer lens is integrally formed on the photoelectric conversion unit.
According to this configuration, the vertical dimension can be further reduced, and a highly reliable solid-state imaging device can be provided.

Further, the method of the present invention is the method for producing a solid-state imaging device, comprising: a photoelectric conversion unit; and a charge transfer unit including a charge transfer electrode that transfers a charge generated in the photoelectric conversion unit. Forming the inter-electrode insulating film on the surface of the semiconductor substrate on which the gate oxide film is formed, and filling the region surrounded by the inter-electrode insulating film with a metal material, The light receiving region of the converter is defined by the outer end of the charge transfer electrode.
According to this configuration, a low-resistance charge transfer electrode can be obtained, and the charge transfer electrode itself has a light shielding property, so that a light shielding film becomes unnecessary. Therefore, the number of man-hours can be reduced, and the photoelectric conversion region is defined in a self-aligned manner with the edge of the charge transfer electrode while realizing reliable light shielding by the charge transfer electrode made of a metal material. Thus, the photoelectric conversion area can be expanded to the maximum.

  According to the method of the present invention, in the above method, the step of forming the charge transfer electrode includes a step of forming a gate oxide film on the surface of the semiconductor substrate, Forming a pattern of a layered silicon-based conductive film; forming a radical oxide film by low-temperature plasma on a sidewall of the first-layered silicon-based conductive film; forming an interelectrode insulating film; The step of forming a two-layer silicon-based conductive film, and the first-layer silicon-based conductive film and the second-layer silicon-based conductive film are juxtaposed across the interelectrode insulating film, A step of planarizing the second layer silicon-based conductive film, a step of etching away the first layer silicon-based conductive film and the second layer silicon-based conductive film, and the first layer silicon-based conductive film And second layer silicon-based conductivity Doo is etched region, and a step of filling a metal material.

  According to this configuration, since the insulating film is formed by radical oxidation using high-density low-temperature plasma, a dense and high-quality oxide film is formed without being exposed to a high temperature of 900 to 950 ° C. as in the prior art. Thus, since formation at a low temperature is possible, it is possible to form a highly reliable film without increasing the diffusion length of the underlying impurity region. Even if a CVD film is formed on the radical oxide film, a high-quality insulating film having high insulation resistance can be obtained.

  In the method of the present invention, the step of forming the charge transfer electrode includes a step of forming a pattern of the first layer conductive film constituting the first electrode, an interelectrode insulating film on at least the side wall of the first electrode, and Forming an insulating film, forming a second layer conductive film constituting a second electrode on the surface of the semiconductor substrate on which the first electrode and the interelectrode insulating film are formed, and at least the Removing the second-layer conductive film on the first electrode, and planarizing the surface of the semiconductor substrate on which the second conductive film is formed. By performing radical oxidation by plasma and performing interlayer oxidation, oxidation without crystal orientation dependency is possible, and variation in charge transfer electrode width as seen in normal thermal oxidation can be reduced.

According to this configuration, since the interelectrode insulating film is formed by the process of forming the radical oxide film by low-temperature plasma, it can be formed without causing an increase in the diffusion length of the impurity region formed in the base substrate. is there.
In particular, when forming an interelectrode insulating film, by using radical oxidation by low-temperature plasma and performing interlayer oxidation, it becomes possible to oxidize without crystal orientation dependence, and the variation in the width of the charge transfer electrode as seen in normal thermal oxidation is reduced. Can be reduced.
Further, according to such a configuration, the sidewall insulating film is formed in a self-aligning manner, and thereafter, the silicon-based conductive film is removed leaving the sidewall insulating film, and the metal material is filled again. It is possible to reduce the resistance of the electrode without being affected by misalignment in the photolithography process or halation due to reflection on the surface specific to the metal material.

  In addition, a photolithography process and an etching process necessary for forming a low resistance layer such as a metal layer are not required, and the yield can be improved by reducing the number of processes.

  In this way, it is only necessary to use a photolithography process in the patterning process of the silicon-based conductive film. A sidewall insulating film is formed at the end of the pattern, and the silicon-based conductive film is temporarily removed leaving the sidewall insulating film. Thereafter, a metal silicide film is formed in a self-aligned manner, and a low-resistance charge transfer electrode can be easily formed.

In the method for manufacturing a solid-state imaging device according to the present invention, the step of forming the interelectrode insulating film is formed in two steps: a step of forming a radical oxide film by low-temperature plasma and a step of forming a CVD film. Including.
According to this configuration, a dense and high-quality insulating film can be formed.

  In the method of the present invention, the CVD step includes a step of forming a silicon nitride film.

  According to this configuration, a dense and high-quality insulating film can be formed.

  The method for manufacturing a solid-state imaging device of the present invention includes a step of forming a silicon nitride film on the charge transfer electrode by a plasma CVD method, and a step of forming an in-layer lens on the upper layer.

  According to this configuration, the vertical shrink can be easily achieved.

  The method for manufacturing a solid-state imaging device of the present invention includes a step of forming a color filter layer on the intralayer lens.

  According to this configuration, since the color filter layer is formed on the surface of the charge transfer portion that is flatter, the thickness can be further reduced.

According to the above configuration, since the charge transfer electrode material also serves as a light-shielding film, the opening of the photoelectric conversion unit can be maximized and sensitivity can be increased.
In addition, it is possible to obtain a sensor that can achieve low resistance wiring and can be driven at high speed.
Furthermore, by forming an aspheric inner lens, it is possible to further improve the light collection efficiency and provide a highly sensitive sensor.
In addition, by forming a gap between adjacent electrodes by radical oxidation with low-temperature plasma on the pattern of a silicon-based conductive film, a denser and higher-quality interelectrode insulating film can be formed. This leads to miniaturization of the electrodes.

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)

  As shown in FIG. 1 and FIG. 2 (FIG. 1 is a diagram showing a cross section AA in FIG. 2), the solid-state imaging device of the present embodiment includes a photodiode region 30 as a photoelectric conversion unit, and the photoelectric conversion unit. In the solid-state imaging device including the charge transfer unit 40 having a charge transfer electrode for transferring the charge generated in step 1, the charge transfer electrode 3 is a metal film (metal metal) made of a two-layer film of titanium nitride and tungsten. And a light receiving region of the photoelectric conversion portion is defined by an outer end of the charge transfer electrode 3. The interelectrode insulating film 5 for defining the charge transfer electrodes individually is composed of a two-layer film of a radical oxide film and a silicon nitride film formed by a CVD method, and the charge transfer electrodes are arranged at extremely fine intervals. Yes.

As shown in FIGS. 1 and 2, the silicon substrate 1 has a plurality of photodiode regions 30 constituting a photoelectric conversion unit, and a charge transfer unit 40 for transferring signal charges detected by the photodiode. , Formed between the photodiode regions 30.
About parts other than a charge transfer part, it forms similarly to a usual solid-state image sensor.

  Here, the effective imaging region is composed of a light receiving region including a photoelectric conversion unit and a vertical transfer path (a part of the charge transfer unit) and a horizontal transfer path (a part of the charge transfer unit), and a peripheral circuit outside thereof. As an output circuit.

  Here, the gate oxide film 2 is formed to have a total film thickness of about 50 nm of the radical oxide film and the CVD film. Although not shown, a horizontal transfer register, a signal processing circuit, and wiring for transferring signal charges in the horizontal direction are formed on the non-imaging region of the silicon substrate 1 and the element isolation region of the charge transfer unit.

  That is, as shown in FIG. 1 and FIG. 2, a schematic cross-sectional view and a plan view of the solid-state imaging device chip (FIG. 1 is a cross-sectional view taken along line AA in FIG. 2). ) Are formed with a photoelectric conversion part and a charge transfer part provided with a photodiode, 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.

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

  On the right side of the photodiode 30, a charge transfer channel 33 composed of an n region is formed with a slight distance. A charge readout region 34 is formed in the p-well layer 1P between the n region 30b and the charge transfer channel 33.

A charge transfer electrode 3 is formed on the charge readout region 34 and the charge transfer channel 33 via the gate oxide film 2. An interelectrode insulating film 5 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, and is separated from the adjacent photodiode 30.

  The upper layer of the charge transfer electrode 3 is a silicon oxide film 7 (passivation film), an insulating film 8 made of BPSG (borophosphosilicate glass), an inner lens 73 made of P-SiN, and a flattening under a filter made of transparent resin. A film 74 is formed. Above these, a color filter 50 (red filter 50R, green filter 50G, blue filter: not shown) and a micro lens 60 are provided.

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.
Although FIG. 2 shows a so-called honeycomb-structured solid-state imaging device, it is needless to say that the present invention can also be applied to a square lattice type solid-state imaging device.

Next, the manufacturing process of the solid-state imaging device of the present embodiment will be described with reference to FIGS. 3 to 8 are explanatory views taken along the line BB in FIG.
First, an n-type silicon substrate 1 is prepared, and an n having an impurity concentration of about 1.0 × 10 ¹⁶ cm ^{−3 in} which the charge transfer channel 33, the channel stop region 32, and the charge readout region 34 illustrated in FIG. 1 are formed. A gate oxide film 2 having a two-layer structure is formed on the surface of the silicon substrate 1 of the mold, which is composed of a silicon oxide film having an oxide film thickness of 15 to 35 nm by radical oxidation by low-temperature plasma and a silicon oxide film by CVD.

  Subsequently, a doped amorphous silicon film D1 is formed on the gate oxide film 2 by a low pressure CVD method, and a two-layer film D4 of a silicon oxide film and a silicon nitride film 5 is formed by a low pressure CVD method. A resist pattern R1 is formed (FIG. 3A). This resist pattern is formed so as to correspond to the pattern of every other charge transfer electrode.

  Subsequently, the two-layer film D4 is etched by reactive ion etching to form a mask pattern for patterning the doped amorphous silicon film D1 (FIG. 3B).

  Then, the resist pattern is removed by ashing (FIG. 3C).

  Subsequently, radical oxidation by low-temperature plasma is performed on the surface of the electrode pattern and film formation is performed by the CVD method to form an interelectrode insulating film 5 made of a silicon oxide film having the same thickness as the gate oxide film having a two-layer structure (exactly here Then, a portion 5a serving as a core of the interelectrode insulating film 5 is formed as an interelectrode insulating film 5a) (FIG. 4A).

  Subsequently, a doped amorphous silicon film D2 is formed again by the low pressure CVD method and planarized by CMP (FIG. 4B). Thereafter, the doped amorphous silicon film D2 is patterned by photolithography so as to form the charge transfer electrode, and then etched (FIG. 4C).

  Then, radical oxidation is performed to form a silicon oxide film 4S (FIG. 5A), and after forming a silicon nitride film as the antireflection film 6, ion implantation for forming a photodiode portion is performed. Thereafter, flash lamp annealing is performed to activate the implanted ions. Then, a silicon oxide film 7 is formed on the surface by the CVD method (FIG. 5B).

  Then, a BPSG film 8 having a thickness of 700 nm is formed on this upper layer, and is reflowed and flattened at 850 ° C. (FIG. 5C).

  Next, CMP is performed using the silicon nitride film 6 as an antireflection film as a polishing prevention layer. Thereafter, the silicon nitride film and the silicon oxide film are etched away by anisotropic etching (FIG. 6A), and the exposed doped amorphous silicon layers D1 and D2 are etched away (FIG. 6B). A shape in which the charge transfer electrode formation region is exposed across the inter-layer insulating film 5a is obtained.

  Subsequently, after radical oxidation by low-temperature plasma, a silicon nitride film 5b is formed by plasma CVD, and the surface of the silicon nitride film 5b is radically oxidized to form a silicon oxide film 5c, thereby forming an interelectrode insulating film 5. (FIG. 6C).

  Next, a two-layer film of a TiN layer and a W layer is formed by the CVD method, and planarized by the CMP method to form the metal electrode 3. At this time, after removing the silicon nitride film 5b as an anti-polishing layer in the CMP process, a silicon oxide film 7 is formed by plasma CVD (FIG. 7).

  Next, a silicon nitride film 73 as a lens material is formed by plasma CVD. Then, a resist is applied, a pattern is formed by photolithography, heated and melted, and then the lens-shaped first resist pattern R1 is cured by ion implantation (FIG. 8A).

  Thereafter, a second resist pattern R2 is formed to form an aspherical outer surface (FIG. 8B). Then, the silicon nitride film 73 having the same etching rate as that of the surface member made of the first and second resist patterns is etched back to form an in-layer lens (FIG. 8C). Then, a flattening film 74, a color filter 50, a microlens 60, and the like are formed to obtain a solid-state imaging device as shown in FIGS. In FIG. 2, only the main part is shown, and the optical system and the like are omitted.

  According to this configuration, a low-resistance charge transfer electrode can be obtained, and the charge transfer electrode itself has a light shielding property, so that a light shielding film becomes unnecessary. Therefore, the light-receiving area is defined in a self-aligned manner with the edge of the charge transfer electrode while realizing reliable light shielding by the charge transfer electrode made of a metal material, and the photoelectric conversion area is expanded to the maximum. Is possible.

  According to this method, the inter-electrode gap is determined by the inter-electrode insulating film based on the insulating film formed by oxidation of the silicon-based conductive film such as doped amorphous silicon. A gap can be formed. In addition, a dense and high withstand voltage insulating film can be obtained while using low-temperature oxidation by using radical oxidation, so that the diffusion length is prevented from increasing and a highly accurate and reliable solid-state imaging device is formed. be able to. In particular, since the inter-electrode insulating film including the gate oxide film is formed by the two-layer film of the silicon oxide film and the CVD film by radical oxidation by low-temperature plasma, it can be formed at a low temperature without causing an increase in the base diffusion length. A high-quality insulating film can be formed, an interelectrode insulating film with high accuracy and high withstand voltage can be formed, and a solid-state imaging device with high reliability can be formed. Further, since radical oxidation is a low-temperature process, the diffusion length is hardly increased even if it is repeated many times, and a high breakdown voltage can be reliably achieved.

  In the first embodiment, the interelectrode insulating film 5 is formed by a three-layer film of a silicon oxide film by radical oxidation by low-temperature plasma, a silicon nitride film by CVD method, and a silicon oxide film by radical oxidation by low-temperature plasma. Needless to say, a single layer film may be used.

(Embodiment 2)
Further, a pattern of a phosphorus-doped doped amorphous silicon film D1 is formed on the gate oxide film 2, and after forming a silicon oxide film 5a by radical oxidation by low-temperature plasma and a silicon nitride film 5b by CVD, reactive ions are formed. Etching may remain only on the side wall of D1, and this may be used as an interelectrode insulating film.

(Embodiment 3)
In the above embodiment, a silicon-based conductive film such as amorphous silicon is used as a dummy electrode, and this is oxidized to form an interelectrode insulating film. And an interelectrode insulating film may be formed by filling the interelectrode gap with an insulating film.

  As described above, according to the method of the present invention, the charge transfer electrode is made of a light-shielding material and it is not necessary to form a light-shielding film, so that the opening of the photoelectric conversion unit can be maximized. Therefore, the photoelectric conversion part can be miniaturized. Further, by configuring the charge transfer electrode with a metal material film, the resistance can be reduced, and the film thickness and the electrode area can be miniaturized.

  The charge transfer electrode is not limited to a metal material film, and may be a composite film such as tungsten silicide, a laminated film of a polycrystalline silicon film and a tungsten film, and includes a light-shielding conductive layer. If it is.

  According to this configuration, the opening of the photoelectric conversion unit can be maximized, the sensitivity can be increased, a low-resistance wiring can be achieved, and a sensor capable of high-speed driving can be obtained. Therefore, it is useful as a solid-state image sensor in electronic devices such as next-generation mobile phones and digital cameras.

It is a figure which shows the solid-state image sensor of Embodiment 1 of this invention. It is a figure which shows the solid-state image sensor of Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process of the solid-state image sensor of Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process of the solid-state image sensor of Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process of the solid-state image sensor of Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process of the solid-state image sensor of Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process of the solid-state image sensor of Embodiment 1 of this invention. It is sectional drawing 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 Vertical charge transfer electrode 5a Silicon oxide film 5b Silicon nitride film 5c Silicon oxide film 5 Interelectrode insulating film 7 Silicon oxide film 8 BPSG film 30 Photoelectric conversion part 40 Charge transfer part 50 Color filter 60 Lens 8 BPSG film 71M Light-shielding film 73 In-layer lens 74 Flattening film

Claims (15)

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 solid-state imaging device, wherein the charge transfer electrode includes a metal material film, and a light receiving region of the photoelectric conversion unit is defined by an outer end of the charge transfer electrode. The solid-state imaging device according to claim 1,
The metal material film is a solid-state imaging device having a single layer structure. The solid-state imaging device according to claim 1,
The metal material film is a solid-state imaging device having a laminated structure. The solid-state imaging device according to claim 1,
The metal material film is a solid-state imaging device containing tungsten. The solid-state imaging device according to claim 1,
The metal material film is a solid-state imaging device having a laminated structure of a titanium nitride layer and a tungsten layer. A solid-state imaging device according to any one of claims 1 to 5,
The charge transfer electrode has a single-layer electrode structure of a first electrode and a second electrode formed via an interelectrode insulating film covering a side wall of the first electrode;
The solid-state image sensor in which the said interelectrode insulating film contains the radical oxide film by a low temperature plasma. The solid-state imaging device according to claim 6,
A solid-state imaging device in which the inter-electrode insulating film has a two-layer film structure of a radical oxide film formed by low-temperature plasma and a CVD film. The solid-state imaging device according to claim 7,
The solid-state imaging device, wherein the CVD film is a silicon nitride film. A solid-state imaging device according to any one of claims 1 to 8,
A solid-state imaging device in which a photoelectric conversion unit is disposed on the periphery of the charge transfer electrode without a light shielding film. The solid-state imaging device according to any one of claims 1 to 9,
A solid-state imaging device in which an in-layer lens is integrally formed on the photoelectric conversion unit. In a method for manufacturing a solid-state imaging device comprising a photoelectric conversion unit on a semiconductor substrate surface, 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:
Forming an interelectrode insulating film on the surface of the semiconductor substrate on which the gate oxide film is formed;
Filling a region surrounded by the interelectrode insulating film with a metal material,
A method of manufacturing a solid-state imaging device, wherein a light receiving region of the photoelectric conversion unit is defined by an outer end of the charge transfer electrode. It is a manufacturing method of the solid-state image sensing device according to claim 11,
The step of forming the charge transfer electrode comprises:
Forming a gate oxide film on the surface of the semiconductor substrate;
Forming a pattern of a first-layer silicon-based conductive film on the surface of the semiconductor substrate on which the gate oxide film is formed;
Forming a radical oxide film by low-temperature plasma on the sidewall of the first layer silicon-based conductive film, and forming an interelectrode insulating film;
Forming a second-layer silicon-based conductive film on the upper layer;
Flattening the second layer silicon-based conductive film so that the first layer silicon-based conductive film and the second layer silicon-based conductive film are juxtaposed across the interelectrode insulating film When,
Etching away the first layer silicon-based conductive film and the second layer silicon-based conductive film;
A method of manufacturing a solid-state imaging device, including a step of filling a metal material in a region where the first layer silicon-based conductive film and the second layer silicon-based conductive film are etched. It is a manufacturing method of the solid-state image sensing device according to claim 12,
A method of manufacturing a solid-state imaging device, wherein the step of forming the interelectrode insulating film is formed by two steps of a step of forming a radical oxide film by low-temperature plasma and a step of forming a CVD film. It is a manufacturing method of the solid-state image sensing device according to claim 13,
Forming a silicon nitride film on the charge transfer electrode by a plasma CVD method;
Forming a lens in the upper layer, and a method for manufacturing a solid-state imaging device. It is a manufacturing method of the solid-state image sensing device according to claim 14,
A method for manufacturing a solid-state imaging device, including a step of forming a color filter layer on the intra-layer lens.

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