JP3677159B2 - Manufacturing method of solid-state imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a solid-state imaging device, and more particularly, to a method for manufacturing a solid-state imaging device in which reflected light is reduced and sensitivity is improved by providing an antireflection film above a photosensor portion. Is.
[0002]
[Prior art]
A conventional solid-state imaging device using a charge coupled device (CCD) or the like has a silicon oxide film formed above a photosensor portion that performs photoelectric conversion formed in a silicon substrate, and a gate. An electrode, an interlayer insulating film, a metal light shielding film, a passivation film, and the like are sequentially formed. However, in such a film configuration, the reflection on the surface of the photosensor part is large due to the refractive index relationship between the silicon oxide film and the photosensor part, and most of the incident light is lost light. Therefore, in order to suppress reflection on the surface of the sensor unit, an attempt has been made to improve the sensitivity by forming an antireflection film 75 on the silicon oxide film 73a on the photosensor unit 71 as shown in FIG. (For example, Japanese Unexamined Patent Publication No. 60-177778 discloses a solid-state imaging device having this type of structure.) As the antireflection film 75, for example, a silicon nitride film is used, and the sensitivity of the photosensor unit 71 is improved by the interference effect with the silicon oxide film 73a and further by the interference effect including the interlayer insulating film 77 and the like. Yes.
[0003]
Further, as shown in FIG. 8, a silicon nitride film 83b formed between the gate electrode 84 and the silicon substrate 80 is also formed above the photosensor portion 81 in order to ensure insulation between the gate electrode 84 and the silicon substrate 80, and the same as described above. Attempts have also been made to produce antireflection films (for example, JP-A-4-206751).
[0004]
[Problems to be solved by the invention]
However, it is difficult to say that the conventional antireflection film can sufficiently suppress the reflection of the signal light incident on the light receiving region.
[0005]
For example, in the film configuration as shown in FIG. 7, when the silicon oxide film 73 c is formed as an insulating film by oxidizing polycrystalline silicon constituting the gate electrode 74, the silicon oxide film above the photosensor portion 71 is formed. There is a problem in that the film thickness increases, and the reflectivity increases as the film thickness increases. This is because oxygen supplied from the atmosphere for the oxidation of polycrystalline silicon passes through the silicon oxide film 73a and reaches the silicon substrate 70, and the silicon in the substrate is oxidized. For this reason, for example, the above-mentioned Japanese Patent Application Laid-Open No. 60-177778 states that it is difficult to manufacture a silicon oxide film thinner than 100 nm.
[0006]
Further, for example, in the film configuration as shown in FIG. 8, the laminated structure of the silicon oxide film 83a and the silicon nitride film 83b is used for insulation between the gate electrode and the silicon substrate and for antireflection. Therefore, it is not always easy to make the film thickness suitable for the purpose of antireflection, and there is a problem that the antireflection effect cannot be obtained sufficiently.
[0007]
The present invention has been made in view of such circumstances, and an object thereof is to provide a method for manufacturing a solid-state imaging device having a configuration capable of effectively suppressing reflection of signal light incident on a photosensor unit. To do.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a method of manufacturing a solid-state imaging device according to the present invention includes a step of forming a silicon oxide film on a silicon substrate having a photosensor part, Forming an antireflection film on the silicon oxide film, and forming a gate electrode made of polycrystalline silicon on the silicon substrate through at least the silicon oxide film and the antireflection film, After the step of forming the gate electrode, a step of further forming an antireflection film on the antireflection film in the light receiving region through which the light incident on the photosensor portion is transmitted It is characterized by implementing.
[0014]
By adopting such a manufacturing method, the antireflection effect can be improved by increasing the film thickness of the antireflection film above the photosensor. Although the silicon oxide film and the antireflection film also serve to moderately insulate between the gate electrode and the silicon substrate, an appropriate film thickness of these insulating films that insulates between the electrode and the substrate even if the manufacturing method is performed. Is secured.
[0015]
In the said manufacturing method, it is preferable to increase the film thickness of the said antireflection film to 30 nm-80 nm by forming an antireflection film further on the said antireflection film. According to this preferable example, reflection of incident light can be more effectively suppressed.
[0016]
Manufacturing method of solid-state imaging device of the present invention capable of achieving the above object Another The structure includes a step of forming a silicon oxide film on a silicon substrate having a photosensor portion, a step of forming a silicon nitride film on the silicon oxide film, and at least the silicon oxide film and the silicon on the silicon substrate. Forming a gate electrode made of polycrystalline silicon through a nitride film; exposing the gate electrode to an oxidizing atmosphere; and a light receiving region on the silicon oxide film through which incident light to the photosensor portion is transmitted Etching the silicon nitride film in the light receiving region after the step of exposing the gate electrode to an oxidizing atmosphere and before the step of forming the antireflection film. The step of removing is performed.
[0017]
With this manufacturing method, when the polycrystalline silicon is oxidized, it is possible to suppress an increase in the thickness of the silicon oxide film on the photosensor due to the presence of the silicon nitride film. It is possible to improve the antireflection effect by reducing the thickness of the film, and it is possible to realize manufacture of a solid-state imaging device with improved sensitivity. In addition, since the antireflection film is formed by a single film formation process, variations in the film thickness of the antireflection film are small, and the film thickness can be easily controlled.
[0018]
Further, in each of the above manufacturing methods, it is preferable to use a silicon nitride film as the antireflection film.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0020]
(First embodiment)
FIG. 1 is a process diagram showing an outline of an example of the production method of the present invention from the cross-sectional direction. First, a photosensor portion (light receiving portion) 11 that is an n-type impurity region is formed in the p-type silicon substrate 10 by an ion implantation method together with the vertical transfer register 12 and the like, and then a silicon oxide film is formed on the silicon substrate 10. 13a is formed by thermal oxidation.
At this time, the film thickness ta of the silicon oxide film 13a is about 40 nm to 80 nm. A silicon nitride film 13b and a polycrystalline silicon film 14 are sequentially formed on the silicon oxide film 13a by a CVD method. At this time, the film thickness of the silicon nitride film 13b is about 20 nm to 60 nm, and the film thickness of the polycrystalline silicon film 14 is about 200 nm to 600 nm. A part of the silicon nitride film 13b and the polycrystalline silicon film 14 is removed by etching, and an opening region is formed so as to include the photosensor portion 11 (FIG. 1A). By such patterning, the polycrystalline silicon film 14 becomes a gate electrode, and the silicon oxide film 13a and the silicon nitride film 13b function as an insulating film between the gate electrode and the silicon substrate.
[0021]
Next, the polycrystalline silicon film 14 is thermally oxidized, and a silicon oxide film 13 c is formed on the polycrystalline silicon film 14. At this time, since oxygen in the atmosphere supplied to oxidize the polycrystalline silicon film 14 passes through the silicon oxide film 13a and reaches the silicon substrate 10 as well, the silicon substrate 10 in the opening region is also oxidized at the same time. As a result, the film thickness of the silicon oxide film 13a increases (FIG. 1B). The increased film thickness tb is typically about 60 nm to 100 nm.
[0022]
Subsequently, a step of reducing the film thickness of the silicon oxide films 13a and 13c is performed by etching (FIG. 1C). Although not particularly limited, for example, wet etching using a hydrofluoric acid (hydrofluoric acid aqueous solution) -based etching solution can be applied. The etching time is controlled so that the film thickness tc of the silicon oxide film 13a above the photosensor portion 11 is 10 nm to 40 nm, more preferably 20 nm to 30 nm. In order to easily control the film thickness tc, it is preferable to use so-called buffered hydrofluoric acid (mixed liquid of hydrofluoric acid and aqueous ammonium fluoride) as the hydrofluoric acid-based etching liquid.
[0023]
A silicon nitride film 15 is formed by low pressure CVD on the silicon oxide films 13a and 13c whose thickness has been reduced by etching. The film thickness td of the silicon nitride film 15 is 20 nm to 120 nm, preferably 30 nm to 80 nm, and more preferably 50 nm to 70 nm. The silicon nitride film 15 is patterned by forming a resist 16 and etching (FIG. 1D). As a result, the silicon nitride film 15a remaining above the photosensor portion 11 becomes an antireflection film (FIG. 1E). ). As the etching of the silicon nitride film, dry etching is preferable.
[0024]
On top of this, an interlayer insulating film 17, a metal light shielding film 18 patterned so as to form an opening region 18a above the photosensor portion 11, and a passivation film 19 are further formed in this order (FIG. 1 (f)). Although not particularly limited, for example, the interlayer insulating film 17 is a silicon oxide film formed by a low pressure CVD method, and the metal light shielding film 18 is an aluminum film formed by a sputtering method as the passivation film 19. A silicon nitride film formed by a plasma CVD method can be applied to each. Further, the film thickness of the interlayer insulating film 17 is preferably 80 nm to 400 nm. The opening region 18a of the metal light shielding film 18 functions as a light receiving region through which incident light to the photosensor unit 11 is transmitted.
[0025]
A flattening film forming step and the like are appropriately added to the series of steps as described above to manufacture a solid-state imaging device. In the above process, since the thickness of the silicon oxide film is reduced by etching, the antireflection effect after the formation of the silicon nitride film as the antireflection film is improved.
[0026]
In the above process, the silicon nitride film (refractive index 2.0) is exemplified as the antireflection film 15a and the passivation film 19, but the present invention is not limited to this, and the process can be adapted to the above series of processes. The film may be formed by a material having a refractive index higher than that of the silicon oxide film. For example, the object of the present invention can be achieved even when a silicon oxynitride film (SiON film), a cerium oxide film, a titanium oxide film, a tantalum oxide film, a zirconium oxide film, or a mixture thereof is used. . Similarly, as the interlayer insulating film 17, a silicon oxide film (refractive index: 1.45) formed by the CVD method is exemplified, but is not limited thereto.
[0027]
In addition, thermal oxidation, various CVD methods, and the like in the manufacturing process may be basically performed according to ordinary methods. For example, thermal oxidation may be performed at a temperature of about 900 ° C.
[0028]
(Second Embodiment)
FIG. 2 is a process diagram showing an outline of another example of the production method of the present invention from the cross-sectional direction. Also in this manufacturing method, a silicon oxide film 23a, a silicon nitride film 23b patterned so as to have an opening region above the photosensor part, and a polycrystalline silicon film 24 are sequentially formed on the silicon substrate 20 on which the photosensor part 21 is formed. The processes up to the step of forming the silicon oxide film 23c by thermally oxidizing the polycrystalline silicon film 24 are the same as those described in the first embodiment (FIGS. 2A and 2B). ).
[0029]
However, the second embodiment is different from the first embodiment in that the subsequent etching of the silicon oxide film is performed only on the silicon oxide film 23 a above the photosensor unit 21. That is, in this embodiment, the resist 26a is applied and formed in a region excluding the upper portion of the photosensor portion 21, and then etching is performed, and the silicon oxide film 23c formed by thermal oxidation of the polycrystalline silicon 24 is protected, while The silicon oxide film 23a above the sensor unit 21 is removed (FIG. 2C). Subsequently, the once removed silicon oxide film is formed again by thermal oxidation. The film thickness tc at this time is 10 nm to 40 nm, preferably 20 nm to 30 nm (FIG. 2D).
[0030]
The subsequent manufacturing process is basically the same as that shown in FIG. 1, in which a silicon nitride film 25 is formed, and a resist 26b for patterning the nitride film is applied (FIG. 2E). Next, the silicon nitride film 25 is patterned to form an antireflection film 25a (FIG. 2 (f)), and further, an interlayer insulating film 27, a metal light shielding film 28 having an opening region 28a, and a passivation film 29 are sequentially formed (FIG. FIG. 2 (g)).
[0031]
In the series of steps, materials that can be used, film forming methods, and the like are the same as those in the first embodiment.
[0032]
Also in such an embodiment, as in the first embodiment, the thickness of the silicon oxide film under the antireflection film can be set within a preferable range for antireflection. According to this method, since the silicon oxide film is regenerated by thermal oxidation, the film thickness variation of the silicon oxide film is increased because the variation in the film thickness of the silicon oxide film is formed through the oxidation process of polycrystalline silicon. There is an advantage that the thickness of the silicon oxide film is relatively easy to adjust because it is not affected by variations in tb (up to about 10 nm when tb is 100 nm).
[0033]
However, when manufacturing a solid-state image sensor according to this embodiment, it is necessary to pay attention so that the so-called gate bird's beak does not affect the performance of the solid-state image sensor. That is, when the silicon substrate is simultaneously oxidized when the silicon oxide film is regenerated by thermal oxidation, the silicon oxide film expands, and when the gate bird's beak 69 is significantly generated as shown in FIG. The film 63a pushes up the end of the polycrystalline silicon film 64, which is a gate electrode (as if it is a bird's beak), and also presses the silicon substrate 60 at the corresponding position. Such deformation or compression of the gate electrode or the silicon substrate is not preferable because it causes dark current (caused by white defects and a factor of degrading image quality) resulting from a signal defect. Therefore, from this point of view, it is preferable to reduce the thickness of the silicon oxide film according to the first embodiment. Even when the silicon oxide film is regenerated according to the second embodiment, the gate bird's beak improves the image quality. It is preferable to adjust thermal oxidation conditions and the like so as not to have an effect.
[0034]
(Third embodiment)
FIG. 3 is a process diagram showing the outline of still another example of the production method of the present invention by each cross section. First, a photosensor portion 31 that is an n-type impurity region is formed in the p-type silicon substrate 30 together with the vertical transfer register 32 and the like by ion implantation, and then a silicon oxide film 33a is formed on the substrate 30 by thermal oxidation. Is done. The film thickness te of the silicon oxide film 33a is about 20 nm to 40 nm. A silicon nitride film 33b and a polycrystalline silicon film 34 are formed on the silicon oxide film 33a by a CVD method. At this time, the film thickness tf of the silicon nitride film 33b is about 20 nm to 40 nm, and the film thickness of the polycrystalline silicon film 34 is about 200 nm to 600 nm. A part of the polycrystalline silicon film 34 is removed by etching, and an opening region is formed so as to include the photosensor portion 31 (FIG. 3A). By this etching patterning, the polycrystalline silicon film 34 functions as a gate electrode, and the silicon oxide film 33a and the silicon nitride film 33b function as an insulating film between the gate electrode and the silicon substrate.
[0035]
Next, the polycrystalline silicon 34 is thermally oxidized to form a silicon oxide film 33 c on the polycrystalline silicon 34. Further, a silicon nitride film 35 is formed on the silicon oxide film 33c by low pressure CVD (FIG. 3B). By forming the silicon nitride film, the thickness of the silicon nitride film above the photosensor unit 31 also increases (tg). The film thickness tg is 20 nm to 120 nm, preferably 30 nm to 80 nm, and more preferably 50 nm to 70 nm.
[0036]
Subsequently, a resist 36 is formed on the silicon nitride film 35 above the photosensor portion 31 (FIG. 3C), etched (preferably dry etching), and silicon nitride in a portion not protected by the resist. The film thickness is reduced (FIG. 3 (d)). In this embodiment, the etching is performed by adjusting the time so that only the thickness of the additionally formed silicon nitride film 35 is removed. In this way, a silicon nitride film having a film thickness larger than that of other portions is formed only in the region covered with the resist 36 above the photosensor portion 31.
[0037]
Thereafter, in the same process as described in the first embodiment, an interlayer insulating film 37, a metal light-shielding film 38 having an opening region 38a, and a passivation film 39 are sequentially formed (FIG. 3E). A flattening film forming step is appropriately added to manufacture a solid-state imaging device.
[0038]
According to the above process, since the silicon nitride film used as the antireflection film is increased from the initially formed film thickness tf, and the film thickness tg is effective for antireflection, the sensitivity is improved. It becomes possible to manufacture the solid-state imaging device.
[0039]
In the above process, the antireflection film is a silicon nitride film. However, the present invention is not limited to this, and the film may be a film as exemplified above. A laminated structure of two or more layers using different kinds of films in combination. You may make it have.
[0040]
In the series of steps, materials that can be used, film forming methods, and the like are the same as those in the first embodiment.
[0041]
(Fourth embodiment)
FIG. 4 is a process diagram showing the outline of still another example of the production method of the present invention by each cross section. Also in this step, the silicon oxide film 43a, the silicon nitride film 43b, and the polycrystalline silicon film 44 patterned so as to have an opening region above the photosensor part 41 are formed on the silicon substrate 40 on which the photosensor part 41 is formed. Then, the polycrystalline silicon film 44 is thermally oxidized to form a silicon oxide film 43c, and a silicon nitride film 45 is further formed to increase the film thickness of the silicon nitride film above the photosensor portion 41. The process up to the step of applying the resist 46 only above the portion 41 is the same as the process described in the third embodiment (FIGS. 4A to 4D).
[0042]
However, this embodiment is different from the third embodiment in that the etching of the silicon nitride film that is subsequently performed is performed until the silicon nitride film other than the portion protected by the resist 46 is removed (FIG. 4 ( e)).
[0043]
Thereafter, in the same process as described in the first embodiment, the interlayer insulating film 47, the metal light shielding film 48 having the opening region 48a, and the passivation film 49 are sequentially formed (FIG. 4F).
[0044]
Even in such a process, as in the third embodiment, it is possible to manufacture a solid-state imaging device in which the thickness of the silicon nitride film is partially optimized as an antireflection film.
[0045]
In these series of steps, usable materials, film forming methods, and the like are the same as those in the first embodiment.
[0046]
In the third and fourth embodiments, a silicon nitride film serving as an antireflection film is formed on a silicon substrate, a gate electrode is formed on the silicon nitride film, and the silicon nitride film is formed even after a subsequent oxidation step. Therefore, the silicon substrate is not oxidized and gate bird's beak does not occur. For this reason, it is possible to reliably prevent the occurrence of white scratches that degrade the image quality.
[0047]
Further, since there is no need to adjust the oxide film thickness by etching the oxide film as in the first embodiment, there is no variation in the thickness of the silicon oxide film on the photodiode within the same wafer or between wafers. Thus, an element having stable optical characteristics can be supplied. Furthermore, since the wet etching process is not required, the manufacturing process can be simplified.
[0048]
(Fifth embodiment)
FIG. 5 is a process diagram showing the outline of still another example of the production method of the present invention by each cross section. In this process, a silicon oxide film 53a, a silicon nitride film 53b, and a polycrystalline silicon film 54 patterned so as to have an opening region above the photosensor unit 51 are formed on the silicon substrate 50 on which the photosensor unit 51 is formed. The processes up to forming the silicon oxide film 53c by sequentially oxidizing the polycrystalline silicon film 54 and forming the silicon oxide film 53c are the same as those described in the third embodiment (FIGS. 5A to 5B). )).
[0049]
However, in the present embodiment, subsequently, a step of removing the silicon nitride film 53b on the photosensor unit 51 by etching is performed (FIG. 5C). This etching is preferably dry etching.
[0050]
Next, a silicon nitride film 55 is newly formed by low pressure CVD (FIG. 5D). The film thickness of the silicon nitride film 55 is 20 to 120 nm, preferably 30 to 80 nm, and more preferably 50 to 70 nm. The silicon nitride film 55 is patterned by forming a resist 56 and etching (FIG. 5E). As a result, the silicon nitride film 55a remaining above the photosensor portion 51 becomes an antireflection film (FIG. 5F). )). The etching of the silicon nitride film 55 is preferably dry etching.
[0051]
Thereafter, in the same process as described in the first embodiment, the interlayer insulating film 57, the metal light shielding film 58 having the opening region 58a, and the passivation film 59 are sequentially formed (FIG. 5E). A flattening film forming step is appropriately added to manufacture a solid-state imaging device.
[0052]
Further, in the above process, the antireflection film is a silicon nitride film, but the film as exemplified above can be used without being limited thereto. In the series of steps, usable materials, film forming methods, and the like are the same as those in the first embodiment.
[0053]
According to the fifth embodiment, since the silicon nitride film is formed on the silicon substrate and the gate electrode is formed thereon as in the third and fourth embodiments, the subsequent oxidation is performed. Even after the process, the silicon substrate is not oxidized, and the thickness of the silicon oxide film above the light receiving region does not increase. Therefore, it is not necessary to adjust the oxide film thickness by etching the oxide film as in the first embodiment, so that variations in the film thickness of the silicon oxide film on the photodiode can be suppressed, and the optical characteristics can be reduced. A stable element can be supplied. In addition, since no gate bird's beak occurs, it is possible to reliably prevent the occurrence of white scratches that degrade the image quality.
In the fifth embodiment, after the step of oxidizing the gate electrode, the silicon nitride film above the light receiving region is temporarily removed, and then a new silicon nitride film is formed as an antireflection film. Therefore, as in the third and fourth embodiments, the antireflection film is formed twice (the antireflection film forming step performed before the polycrystalline silicon formation and the thermal oxidation of the polycrystalline silicon). Compared with the case of forming by the film thickness increasing step of the antireflection film), the variation in the film thickness of the antireflection film is small and the adjustment of the film thickness is easy.
[0054]
【The invention's effect】
As described above in detail, according to the present invention, the step of forming a silicon oxide film on the silicon substrate having the photosensor portion and the polycrystalline silicon is formed on the silicon substrate via at least the silicon oxide film. Forming a gate electrode; exposing the gate electrode to an oxidizing atmosphere; forming a silicon oxide film on the gate electrode; and transmitting light incident on the photosensor portion on the silicon oxide film Forming an antireflection film in the light receiving region, and after the step of exposing the gate electrode to an oxidizing atmosphere and before the step of forming the antireflection film, a silicon oxide film in the light receiving region By carrying out the process of reducing the film thickness of the film by etching, it has a configuration that can effectively suppress the reflection of the signal light incident on the photosensor portion. It is possible to manufacture the body image pickup device.
[0055]
A step of forming a silicon oxide film on the silicon substrate having a photosensor portion; a step of forming an antireflection film on the silicon oxide film; and at least the silicon oxide film and the antireflection film on the silicon substrate. Forming a gate electrode made of polycrystalline silicon via the step, and after the step of forming the gate electrode, on the antireflection film in the light receiving region through which the incident light to the photosensor part is transmitted Further, by performing the step of forming the antireflection film, a solid-state imaging device having a configuration that can effectively suppress the reflection of the signal light incident on the photosensor portion can be manufactured.
[0056]
A step of forming a silicon oxide film on the silicon substrate having a photosensor portion; a step of forming a silicon nitride film on the silicon oxide film; and at least the silicon oxide film and the silicon nitride film on the silicon substrate A step of forming a gate electrode made of polycrystalline silicon through a step, a step of exposing the gate electrode to an oxidizing atmosphere, and a light receiving region on the silicon oxide film through which incident light to the photosensor portion is transmitted. A step of forming an antireflection film, and after the step of exposing the gate electrode to an oxidizing atmosphere and before the step of forming the antireflection film, the silicon nitride film in the light receiving region is removed by etching The solid-state imaging element having a configuration capable of effectively suppressing the reflection of the signal light incident on the photosensor unit also by performing the process It can be produced.
[Brief description of the drawings]
FIG. 1 is a process diagram showing steps of an example of a production method according to the present invention in order with sectional views.
FIGS. 2A and 2B are process diagrams sequentially illustrating the steps of another example of the manufacturing method of the present invention in a sectional view.
FIG. 3 is a process diagram showing steps of another example of the production method of the present invention in order with sectional views.
FIG. 4 is a process chart showing steps of another example of the production method of the present invention in order with sectional views.
FIG. 5 is a process chart showing steps of another example of the production method of the present invention in order with sectional views.
FIG. 6 is an enlarged view of a part of a cross-sectional view corresponding to FIG. 2 (d) for explaining the gate bird's beak.
FIG. 7 is a cross-sectional view showing an example of a conventional solid-state imaging device.
FIG. 8 is a cross-sectional view showing another example of a conventional solid-state imaging device.
[Explanation of symbols]
10, 20, 30, 40, 50, 60, 70, 80 Silicon substrate
11, 21, 31, 41, 51, 61, 71, 81 Photosensor unit
13a, 23a, 33a, 43a, 53a, 63a, 73a, 83a Silicon oxide film
13b, 23b, 33b, 43b, 53b, 63b, 73b, 83b Silicon nitride film
13c, 23c, 33c, 43c, 53c, 63c, 73c, 83c Silicon oxide film
14, 24, 34, 44, 54, 64, 74, 84 Polycrystalline silicon film
15, 25, 35, 45, 55, 65, 85 Silicon nitride film
16, 26a, 26b, 36, 46, 56 resist
17, 27, 37, 47, 57, 67, 77 Interlayer insulating film
18, 28, 38, 48, 58, 68, 78 Metal light shielding film
19, 29, 39, 49, 59, 69, 79 Passivation film
69 Gate Birds Beak

Claims (4)

A step of forming a silicon oxide film on a silicon substrate having a photosensor portion; a step of forming an antireflection film on the silicon oxide film; and at least the silicon oxide film and the antireflection film on the silicon substrate. Forming a gate electrode made of polycrystalline silicon, and after the step of forming the gate electrode, further reflecting on the antireflection film in the light receiving region through which the incident light to the photosensor part is transmitted The manufacturing method of the solid-state image sensor characterized by implementing the process of forming a prevention film. 2. The method of manufacturing a solid-state imaging device according to claim 1, wherein a film thickness of the antireflection film above the photosensor portion is increased to 30 nm to 80 nm by further forming an antireflection film on the antireflection film. . A step of forming a silicon oxide film on the silicon substrate having a photosensor portion; a step of forming a silicon nitride film on the silicon oxide film; and the silicon oxide film and the silicon nitride film on the silicon substrate. A step of forming a gate electrode made of polycrystalline silicon; a step of exposing the gate electrode to an oxidizing atmosphere; and an antireflection film in a light receiving region on the silicon oxide film through which incident light to the photosensor portion is transmitted. A step of removing the silicon nitride film in the light receiving region by etching after the step of exposing the gate electrode to an oxidizing atmosphere and before the step of forming the antireflection film. A method for manufacturing a solid-state imaging device. The method for manufacturing a solid-state imaging device according to claim 1, wherein a silicon nitride film is used as the antireflection film.

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