JP2010129786A - Method of manufacturing solid-state imaging apparatus, and electronic information apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a solid-state imaging apparatus, wherein processing precision of an antireflective film on a photoelectric conversion portion constituting the solid-state imaging apparatus is improved, and the cost reduction is attained. <P>SOLUTION: The method of manufacturing the solid-state imaging apparatus, includes steps of: forming a diffusion layer 10a constituting a photodiode on a surface of a silicon substrate 10; forming first and second gate electrodes 41 and 61, etc., as a transfer electrode portion nearby the diffusion layer on the silicon substrate 10; then forming a nitride film 8 as a constituent material of the antireflective film over the entire surface to a predetermined thickness so that steps of a base are reflected; forming a resists film 93 over the entire surface so that the steps of the base are buried; then etching back the resist film 93 so that the nitride film 8 on the transfer electrode portion is exposed; and dry-etching the nitride film 8 using the etched-back resist film 93 as a mask to selectively remove the nitride film 8 over the transfer electrode portion and the nitride film 8 formed in a sidewall shape on a side surface of the transfer electrode portion. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a solid-state imaging device and an electronic information device, and more particularly, to a method for manufacturing a solid-state imaging device in which the processing steps of an antireflection film disposed on a photoelectric conversion unit of the solid-state imaging device are simplified, and The present invention relates to an electronic information device using the solid-state imaging device obtained by the method for manufacturing the solid-state imaging device.

  2. Description of the Related Art Conventionally, some solid-state imaging devices have improved sensitivity by providing an antireflection film on the light receiving unit (photoelectric conversion unit).

  FIG. 7 is a plan view for explaining such a conventional solid-state imaging device.

  The solid-state imaging device 200 shown in FIG. 7 is a CCD solid-state imaging device. The solid-state imaging device 200 includes a plurality of photodiodes (photoelectric conversion units) 202 arranged in a matrix on the Si substrate 10 and each photoelectric conversion. The vertical transfer unit 203 is arranged to correspond to the column of the unit 202 and transfers the signal charge read from the photodiode 202 in the vertical direction, and the transfer gate (read gate) that reads the signal charge from the photodiode to the corresponding vertical transfer unit 203 ) 204, a horizontal transfer unit 206 that horizontally transfers the signal charge transferred from the vertical transfer unit 203, and an output amplifier 207 that outputs a signal voltage corresponding to the signal charge transferred from the horizontal transfer path 206. And a control unit 2 for controlling the transfer gate 204, the vertical transfer unit 203, and the horizontal transfer unit 206. And a 8.

  FIG. 12B shows a cross-sectional structure (XIIb-XIIb line portion) of the solid-state imaging device 200 shown in FIG.

  A diffusion layer 10a constituting the photodiode 203 is formed on the surface region of the Si substrate 10, and an antireflection film 8a is formed on the diffusion layer 10a with the silicon oxide film 71 interposed therebetween. Further, in the vertical transfer portion on both sides of the diffusion layer 10a, the first gate electrode 41 is connected via a gate insulating film having an ONO structure including the gate oxide film 1, the gate nitride film 2, and the oxide film 3 such as HTO. Further, a second gate electrode 61 is formed on the first gate electrode 41 with a first interlayer insulating film 5 interposed therebetween. The surface of the second gate electrode 61 is covered with the second interlayer insulating film 7.

  In this solid-state imaging device, a light shielding film is formed on the gate electrode, and further, a color filter and a microlens are provided on the antireflection film and the light shielding film via a planarizing film such as an oxide film. Although formed, it is not shown here.

  Next, a method for manufacturing the solid-state imaging device will be described.

  8 (a) to (d), FIG. 9 (a) to (c), FIG. 10 (a) to (d), FIG. 11 (a) to (c), FIG. 12 (a) and FIG. FIG. 2 is a diagram for explaining a manufacturing method of a solid-state imaging device in the order of steps, and particularly shows a processing method of an antireflection film disclosed in Patent Document 1 and the like.

  As shown in FIG. 8A, a gate oxide film 1, a gate nitride film 2, an HTO (High Temperature Oxide) film, etc. are formed on a Si substrate 10 on which a diffusion layer 10a constituting a photodiode is formed in the surface region. The oxide film 3 is sequentially formed by deposition to form an ONO structure insulating film (hereinafter also referred to as ONO film) 20, and then a first polysilicon film serving as a first gate electrode on the insulating film 20. (Hereinafter also referred to as a Poly-Si film) 4 is deposited. The Poly-Si film 4 is doped with impurities (boron or phosphorus) in order to improve conductivity.

  As shown in FIG. 8B, a resist film 91 is formed by patterning a photoresist on the Poly-Si film 4, and as shown in FIG. 8C, the Poly-Si film 4 is processed by dry etching. Thus, the first gate electrode 41 is formed. The resist film 91 is then removed by ashing or the like. Subsequently, as shown in FIG. 8D, the first interlayer insulating film 5 is formed by oxidizing the Poly-Si film constituting the first gate electrode 41 by thermal oxidation. In this thermal oxidation process, the HTO film 3 in the etching region (the portion where the Poly-Si film 4 is removed by etching) is hardly oxidized.

  Next, as shown in FIG. 9A, as in the formation of the first gate electrode, a second polysilicon film (hereinafter also referred to as a Poly-Si film) 6 is deposited, and FIG. As shown in FIG. 9B, a resist film 92 is formed on the Poly-Si film 6 by patterning a photoresist, and the Poly-Si film 6 is processed by dry etching as shown in FIG. A second gate electrode 61 is formed.

  At this time, the HTO 3 and the nitride film 2 in the etching region (the portion where the Poly-Si film 4 has been removed by etching) are removed, and etching is further performed halfway through the underlying oxide film 1. If the oxide film 1 is completely removed, the substrate 10 is damaged and crystal defects are generated, so that the etching of the oxide film 1 is stopped halfway.

  Then, after removing the resist film 61 by ashing or the like as shown in FIG. 10A, the oxide film 1 remaining by wet etching is removed, and as shown in FIG. Thermal oxidation 71 is formed on the surface. At this time, the surface of the second gate electrode 61 is also oxidized, and the second interlayer insulating film 7 is formed.

  Next, as shown in FIG. 10C, a polycrystalline silicon film 11 is formed with a predetermined thickness so that the underlying step is reflected. The thickness of the polycrystalline silicon film 11 is such that the first and second gate electrodes 41 and 61 (hereinafter also referred to as transfer electrode portion) constituting the charge transfer portion and the antireflection film 8a formed thereafter. It is set according to the distance.

  Thereafter, as shown in FIG. 10D, the polycrystalline silicon film 11 is etched back by dry etching to form the sidewalls 12 on the side surfaces of the first and second gate electrodes 41 and 61.

  Thereafter, as shown in FIG. 11A, a nitride film 18 is formed so as to reflect the underlying step. The nitride film 18 has an effect of not reflecting light incident on the diffusion layer 10a that constitutes the photodiode, which is located between the gate electrodes of the substrate.

  Subsequently, as shown in FIG. 11B, a resist material is applied on the entire surface so that the base step is buried, thereby forming a resist film 93. As shown in FIG. 11C, the resist film is melted. Thus, the nitride film 18 on the transfer electrode is exposed.

Further, as shown in FIG. 12 (a), the nitride film on the upper surface of the transfer electrode portion and the nitride film on the side surface of the transfer electrode portion are removed by dry etching, further removing the resist, and thereafter As shown in FIG. 12B, the polycrystalline silicon film 12 on the side surface of the transfer electrode portion is removed.
JP 2007-80941 A

  As described above, in the conventional technique, when the antireflection film is formed on the diffusion layer constituting the photodiode, the polycrystalline silicon film formed on the side wall of the transfer electrode portion located in the vicinity of the diffusion layer is used. Thus, the distance of the antireflection film from the transfer electrode portion is set by the thickness of the polycrystalline silicon film. In other words, the antireflection film is positioned in a self-aligned manner with respect to the transfer electrode portion. Therefore, the position of the antireflection film due to the alignment accuracy when the antireflection film is patterned in the photolithography process. Deviation can be avoided, and sensitivity variations and smear deterioration can be prevented.

  Incidentally, in the conventional solid-state imaging device such as Patent Document 1 described above, the antireflection film is not formed on the entire surface of the substrate, but is formed in an island shape corresponding to the photoelectric conversion portion. One reason is that the antireflection film hinders the sintering process performed on the substrate after the formation.

  Sintering is a process for reducing crystal defects by bonding hydrogen atoms to the dangling bonds of elements such as silicon constituting the substrate, but if the antireflection film is formed on the entire surface, The penetration of hydrogen atoms into the inside will be hindered.

  The second reason is that in a solid-state imaging device, since a light shielding film is formed in a region other than the photoelectric conversion portion on the substrate, if an antireflection film is formed on the entire surface of the substrate, the light shielding film In the opening corresponding to the photoelectric conversion portion, the distance between the substrate and the light shielding film is widened by the film thickness of the antireflection film, and light incident obliquely into the light shielding film opening is incident on the substrate surface and the lower surface of the light shielding film. And multiple reflections between the two and the vertical transfer section, which tends to enter the diffusion layer, resulting in noise.

  For this reason, in the conventional method for manufacturing a solid-state imaging device, the antireflection film is formed by being positioned in a self-aligned manner with respect to the transfer electrode part at a certain distance from the transfer electrode part. .

  However, in the processing method of the antireflection film as performed in the conventional manufacturing method of the solid-state imaging device, formation of a polycrystalline silicon film for positioning the antireflection film in a self-aligned manner with respect to the transfer electrode portion and There is a problem in that a process for removing it is required.

  The present invention has been made to solve the above-described conventional problems, and the antireflection film disposed on the photoelectric conversion portion is self-aligned with the conductor layer disposed around the photoelectric conversion portion. And a solid-state imaging device manufacturing method that can simplify the process for self-aligning positioning of the antireflection film, and such a solid-state imaging device manufacturing method. An object is to obtain an electronic information device using the solid-state imaging device.

  A method for manufacturing a solid-state imaging device according to the present invention includes: a solid-state imaging device having a plurality of photoelectric conversion units that generate signal charges by photoelectric conversion of incident light; and an antireflection film disposed on each photoelectric conversion unit. A method of manufacturing, the step of forming the photoelectric conversion portion on the surface region of the semiconductor substrate and forming a conductor layer on the semiconductor substrate so as to be adjacent to the photoelectric conversion portion, and a material for the antireflection film A step of forming the antireflection material layer over the entire surface so that the step of the base is reflected, and etching selectivity with respect to the antireflection material layer so that the step of the base is embedded on the antireflection material layer A step of forming a base buried layer, a step of etching back the base buried layer so that the antireflection material layer on the conductor layer is exposed, and the antireflection material using the base buried layer as a mask. The photoelectric conversion part To those containing a selectively etching so that the antireflective film is formed, the object can be achieved.

  According to the present invention, in the method for manufacturing a solid-state imaging device, in the selective etching process of the antireflection film material, the antireflection film remaining under the underlying buried layer by the selective etching of the antireflection film material. The material layer is preferably processed by etching so as to have a desired thickness after removing the underlying buried layer.

  According to the present invention, in the manufacturing method of the solid-state imaging device, the antireflection material layer has an antireflection film disposed on the photoelectric conversion unit depending on a film thickness thereof, and the semiconductor substrate is adjacent to the photoelectric conversion unit. It is preferable that the distance between the conductive layer and the conductive layer disposed above is determined.

  In the method for manufacturing a solid-state imaging device according to the present invention, it is preferable that the antireflection material layer has a thickness within a range of 0.2 μm to 0.3 μm.

  In the method for manufacturing a solid-state imaging device according to the present invention, it is preferable that the semiconductor substrate is a silicon substrate and the antireflection material layer is a silicon nitride layer.

  In the method for manufacturing a solid-state imaging device according to the present invention, it is preferable that the selective etching of the silicon nitride layer as the antireflection material layer is performed using a fluorine-based etching gas.

  In the method for manufacturing a solid-state imaging device according to the present invention, it is preferable that the base buried layer is a resist layer formed by coating the entire surface of a resist material.

  According to the present invention, in the method for manufacturing a solid-state imaging device, the etch back of the resist layer as the underlying buried layer is preferably performed using oxygen gas.

  In the method of manufacturing a solid-state imaging device according to the present invention, it is preferable that only the resist layer is selectively etched in the step of etching back the resist layer.

  According to the present invention, in the method for manufacturing a solid-state imaging device, the antireflection material layer is a nitride film, and the resist film that is the base buried layer is used as a mask to selectively select the nitride film that is the antireflection material layer. In the etching step, it is preferable that the nitride film is etched in a self-aligning manner using the resist film as a mask so that a portion located on the photoelectric conversion portion remains in an island shape.

  The present invention preferably includes the step of forming the antireflection film by etching the nitride film formed in the island shape so that the film thickness becomes 30 to 70 nm in the method for manufacturing the solid-state imaging device. .

  The present invention provides the method for manufacturing a solid-state imaging device, wherein the solid-state imaging device includes a charge transfer unit that transfers a signal charge generated by the photoelectric conversion unit, and the conductor layer includes a transfer electrode of the charge transfer unit. It is preferable to constitute.

  In the method for manufacturing a solid-state imaging device according to the present invention, it is preferable that the conductor layer is made of polysilicon and a silicon oxide film is formed on a surface thereof.

  According to the present invention, in the method of manufacturing a solid-state imaging device, the transfer electrode constituting the charge transfer unit includes a first gate electrode made of a first polysilicon layer, and an interlayer insulating film on the first polysilicon. And a second gate electrode made of a second polysilicon formed through the first electrode.

  An electronic information device according to the present invention is an electronic information device including an imaging unit, and uses the solid-state imaging device obtained by the above-described manufacturing method of the solid-state imaging device as the imaging unit. This achieves the above object.

  Hereinafter, the operation of the present invention will be described.

  In the present invention, in the method for manufacturing a solid-state imaging device, a step of forming a photoelectric conversion portion on a surface region of a semiconductor substrate and forming a conductor layer adjacent to the photoelectric conversion portion on the semiconductor substrate, and the reflection A step of forming an antireflection material layer as a material of the antireflection film on the entire surface so that the step of the base is reflected, and etching of the antireflection material layer so that the step of the base is embedded on the antireflection material layer Forming a selective underlying buried layer, etching back the underlying buried layer so that the antireflection material layer on the conductor layer is exposed, and etching the underlying buried layer. As the mask, the antireflection material layer is selectively etched so that the antireflection film is formed on the photoelectric conversion portion. Therefore, the antireflection film remaining by selective etching of the antireflection material layer is Prevention material layer, the thickness of the portion located on the side wall of the conductive layer, and be self-aligned manner positioned relative conductor layer. In addition, the antireflection material layer, which is a constituent material of the antireflection film, also serves as a film for positioning the antireflection film, thereby simplifying the film formation process in the self-alignment formation process of the antireflection film. And throughput can be improved.

  Further, in the process of processing the antireflection material layer into the antireflection film, the antireflection material layer is not patterned by the photolithography process, but the arrangement of the antireflection film is determined by the film thickness of the antireflection material layer. Since the self-aligned patterning of the layers is performed, it is possible to improve the control accuracy of the dimensions of the antireflection film and the overlay accuracy of the antireflection film on the photoelectric conversion unit.

  Further, since the antireflection film is not formed on the conductor layer, the antireflection material layer is not formed on the side wall surface of the conductor layer, and when the conductor layer is covered with the light shielding film, the reflection is performed on the side surface of the conductor layer. It is possible to enlarge the light incident region of the photoelectric conversion unit by the amount that the prevention material layer is not formed, and the sensitivity of the solid-state imaging device can be improved.

  As described above, according to the present invention, a solid-state imaging device including a plurality of photoelectric conversion units that generate signal charges by photoelectric conversion of incident light and an antireflection film disposed on each photoelectric conversion unit is manufactured. In the method, the step of forming the photoelectric conversion portion on the surface region of the semiconductor substrate and forming a conductor layer on the semiconductor substrate so as to be adjacent to the photoelectric conversion portion, and the reflection as a material of the antireflection film A step of forming an anti-reflection material layer on the entire surface so that the step of the base is reflected, and a base embedding having etching selectivity with respect to the anti-reflection material layer so that the step of the base is embedded on the anti-reflection material layer Forming a layer, etching back the underlying buried layer so that the antireflection material layer on the conductor layer is exposed, and using the underlying buried layer as a mask, the antireflection material layer, On the photoelectric conversion part And a step of selectively etching so as to form an anti-reflection film, so that the anti-reflection film arranged on the photoelectric conversion portion is self-aligned with the conductor layer arranged around the photoelectric conversion portion. In addition, the process for self-aligning positioning of the antireflection film can be simplified.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a plan view for explaining a solid-state imaging device obtained by the method for manufacturing a solid-state imaging device according to Embodiment 1 of the present invention. FIGS. 2 to 5 are methods for manufacturing the solid-state imaging device according to Embodiment 1. FIG. 2 is a diagram illustrating the cross-sectional structure of the Xc-Xc line portion of FIG. 1 in the order of steps.

  The solid-state imaging device 100 obtained by the method of manufacturing the solid-state imaging device according to the first embodiment is a CCD solid-state imaging device, similar to the conventional solid-state imaging device shown in FIG. A plurality of photodiodes (photoelectric conversion units) 202 arranged in a matrix form on 10 and a vertical line that transfers signal charges read from the photodiodes 202 in the vertical direction. A transfer unit 203; a transfer gate (read gate) 204 that reads signal charges from a photodiode to a corresponding vertical transfer unit 203; and a horizontal transfer unit 206 that transfers signal charges transferred from the vertical transfer unit 203 in the horizontal direction. An output amplifier 207 that outputs a signal voltage corresponding to the signal charge transferred from the horizontal transfer path 206; Lance fan gate 204, the vertical transfer unit 203, and a control unit 208 for controlling the horizontal transfer unit 206.

  Next, a method for manufacturing the solid-state imaging device according to Embodiment 1 will be described.

  2A to 2D, 3A to 3D, 4A to 4D, and 5A to 5C are diagrams of the solid-state imaging device of the first embodiment. It is a figure explaining a manufacturing method in order of a process.

  After an ONO film 20 made of a gate oxide film 1, a gate nitride film 2, and an HTO (High Temperature Oxide) film is formed on the Si substrate 10 on which the diffusion layer 10a constituting the photodiode is formed in the surface region, this A Poly-Si film 4 is deposited on the ONO film 20 (FIG. 2A).

  Thereafter, a resist film 91 is formed on the Poly-Si film 4 (FIG. 2B), and the Poly-Si film 4 is dry-etched using the resist film 91 as a mask to form a first gate electrode 41 (FIG. FIG. 2 (c)). Thereafter, a first interlayer insulating film 5 is formed on the surface of the first gate electrode 41 by thermal oxidation treatment (FIG. 2D).

  2A to 2D are the same as the steps shown in FIGS. 8A to 8D in the conventional method for manufacturing a solid-state imaging device.

  Next, the second polysilicon film (hereinafter also referred to as a Poly-Si film) 6 is processed by dry etching using the resist film 92 to form the second gate electrode 61 (FIG. 3A to FIG. 3). (D)). Thereafter, the resist film 92 and the remaining oxide film 1 are removed, and a thermal oxidation 71 is formed on the surface of the Si substrate 10. At this time, the surface of the second gate electrode 61 is also oxidized to form the second interlayer insulating film 7 (FIG. 4A).

  3 (a) to 3 (d) and FIG. 4 (a) are steps shown in FIGS. 9 (a) to 9 (c), FIGS. 10 (a) and 10 (b) in the conventional method for manufacturing a solid-state imaging device. It is the same as the process shown.

  Thereafter, in the method of manufacturing the solid-state imaging device according to the first embodiment, as shown in FIG. 4B, a nitride film (silicon nitride film) 8 is formed on the entire surface by deposition so that the underlying step is reflected. The film thickness of the silicon nitride film 8 is set according to the distance between the transfer electrode portion including the first and second gate electrodes 41 and 61 constituting the charge transfer portion and the antireflection film 81a formed thereafter. Here, the thickness is about 0.2 μm to 0.3 μm.

Subsequently, as shown in FIG. 4C, a resist material is applied to the entire surface so that the base step is buried, and a resist film 93 is formed. As shown in FIG. The upper portion of the resist film 93 is removed by dry etching so that the film 8 is exposed. As the etching conditions at this time, the etching selectivity of the resist film 93 to the nitride film 8 must be high. As the etching gas at this time, for example, O ₂ gas is used.

4D, the nitride film 8 formed on the transfer electrode and the nitride film 8 formed in a sidewall shape on the side surface of the transfer electrode are dry-etched using the resist film 93 left in FIG. 4D as a mask. (A)). The etching condition at this time is isotropic etching, and the etching selectivity of the nitride film 8 to the resist 93 and the base oxide film 71 must be high. As the etching gas at this time, a fluorine-based etching gas such as CF ₄ gas or SF ₆ gas is used.

Subsequently, as shown in FIG. 5B, the resist film 93 is peeled off, and as shown in FIG. 5C, the nitride film 81 remaining on the lower side of the resist film 93 is subjected to 30 to 30 by dry etching. The antireflection film 81a is formed by etching back to a thickness of about 70 nm, preferably about 30 to 50 nm. The etching condition at this time is that the etching selectivity of the nitride film 81 with respect to the base oxide film 71 must be high. For example, as the etching gas at this time, a fluorine-based etching gas such as CF ₄ gas or SF ₆ gas is used.

  Thereafter, sintering is performed along with the formation of other components constituting the solid-state imaging device, such as a light shielding film, a color filter, and a microlens.

  As described above, in the method of manufacturing the solid-state imaging device according to the first embodiment, the diffusion layer 10a constituting the photodiode is formed on the surface of the silicon substrate 10, and the first and second diffusion layers 10a are formed in the vicinity of the diffusion layer of the silicon substrate 10. After the gate electrodes 41 and 61 are formed as transfer electrode portions, a nitride film 8 which is a constituent material of the antireflection film is formed with a predetermined thickness on the entire surface to reflect the level difference of the base, and a resist film 93 is formed on the base Then, the resist film 93 is etched back so that the nitride film 8 on the transfer electrode portion is exposed, and the nitride film 8 is dry-etched using the etched back resist 93 as a mask. As a result, the nitride film 8 above the transfer electrode portion and the nitride film 8 formed in a sidewall shape on the side surface of the transfer electrode portion are selectively removed. An antireflection film 81a can be disposed on a in a self-aligned manner with respect to the gate electrodes 41 and 61 as transfer electrode portions, and the nitride film 8 which is a constituent material of the antireflection film 81a includes The film also serves as a film for positioning the antireflection film, the film formation process in the self-aligned formation process of the antireflection film can be simplified, and the throughput can be improved.

  In this embodiment, the patterning of the antireflection film is not patterning by a photolithography process in which the position of the antireflection film is determined by mask alignment, but a film of an antireflection material layer (nitride film) for forming the antireflection film. This is a self-aligned patterning in which the position of the antireflection film is determined by the thickness. For this reason, the control accuracy of the dimensions of the antireflection film and the overlay accuracy of the antireflection film on the photodiode region (photoelectric conversion unit) are improved. be able to.

  As a result, variation in mass production in the manufacturing method of the solid-state imaging device can be suppressed, and furthermore, the manufacturing cost of the solid-state imaging device can be suppressed by reducing the mask accompanying the reduction of the photolithography process by simplifying the film forming process. The effect is obtained.

  Further, since the antireflection film is not formed on the transfer electrode portion including the first and second gate electrodes, the antireflection material layer is not formed on the side wall surface of the transfer electrode portion, and the transfer electrode portion is shielded from light. When covering with a film, it is possible to expand the light incident area of the photoelectric conversion unit by the amount that the antireflection material layer is not formed on the side surface of the transfer electrode unit, thereby improving the sensitivity of the solid-state imaging device. Can do.

  In the first embodiment, the method for manufacturing a CCD solid-state imaging device as a solid-state imaging device has been described as an example. However, the present invention can also be applied to a method for manufacturing a CMOS solid-state imaging device. That is, in the CMOS solid-state imaging device, an antireflection film is formed on a plurality of photoelectric conversion units arranged on the substrate, similarly to the CCD solid-state imaging device. This antireflection film can be formed on the semiconductor substrate in a self-aligned manner with respect to the conductor layer formed so as to be adjacent to the photoelectric conversion portion.

Furthermore, although not specifically described in the first embodiment, a digital video camera, a digital still camera, or the like using a solid-state imaging device obtained by the solid-state imaging device manufacturing method according to the first embodiment as an imaging unit. An electronic information device having an image input device such as a camera, an image input camera, a scanner, a facsimile, a camera-equipped mobile phone device, etc. will be briefly described below.
(Embodiment 2)
FIG. 6 is a block diagram illustrating a schematic configuration example of an electronic information device using, as an imaging unit, the solid-state imaging device obtained by the manufacturing method of the solid-state imaging device of Embodiment 1 as Embodiment 2 of the present invention.

  The electronic information device 190 according to the second embodiment of the present invention shown in FIG. 6 includes the solid-state imaging device obtained by the solid-state imaging device manufacturing method according to the first embodiment of the present invention as an imaging unit 191 that captures an object. A memory unit 192 such as a recording medium for recording data after high-quality image data obtained by photographing by such an imaging unit is subjected to predetermined signal processing for recording, and the image data for display A display unit 193 such as a liquid crystal display device that displays on a display screen such as a liquid crystal display screen after performing predetermined signal processing, and a communication unit such as a transmission / reception device that performs communication processing after processing this image data for predetermined signal processing 194 and at least one of an image output unit 195 that prints (outputs) and outputs (prints out) the image data.

  As mentioned above, although this invention has been illustrated using preferable embodiment of this invention, this invention should not be limited and limited to this embodiment. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge from the description of specific preferred embodiments of the present invention. It is understood that the patent documents cited in the present specification should be incorporated by reference into the present specification in the same manner as the content itself is specifically described in the present specification.

  The present invention relates to a method of manufacturing a solid-state imaging device, and in the field of electronic information equipment, a nitride film, which is a constituent material of an antireflection film, on a portion formed on an upper portion of a transfer electrode portion and on a side wall surface of the transfer electrode portion. Only the portion formed in the sidewall shape is selectively removed, and an island-shaped antireflection film is formed in a self-aligned manner with respect to the transfer electrode portion on the photodiode region (diffusion layer) which is the photoelectric conversion portion. It is possible to provide a method for manufacturing a solid-state imaging device capable of performing the above and an electronic information device using the solid-state imaging device obtained by the method for manufacturing a solid-state imaging device.

FIG. 1 is a plan view illustrating a solid-state imaging device obtained by the method for manufacturing a solid-state imaging device according to Embodiment 1 of the present invention. FIG. 2A to FIG. 2D are views for explaining the manufacturing method of the solid-state imaging device according to the first embodiment in the order of steps. FIG. 3A to FIG. 3D are views for explaining the manufacturing method of the solid-state imaging device according to the first embodiment in the order of steps. 4A to 4D are views for explaining the method of manufacturing the solid-state imaging device according to the first embodiment in the order of steps. FIGS. 5A to 5C are views for explaining the manufacturing method of the solid-state imaging device according to the first embodiment in the order of steps, and FIG. 5C is a cross-sectional view taken along line Xc-Xc in FIG. The structure is shown. FIG. 6 is a block diagram illustrating a schematic configuration example of an electronic information device using, as an imaging unit, the solid-state imaging device obtained by the manufacturing method of the solid-state imaging device of Embodiment 1 as Embodiment 2 of the present invention. FIG. 7 is a plan view for explaining a conventional solid-state imaging device. FIG. 8A to FIG. 8D are diagrams for explaining a conventional method for manufacturing a solid-state imaging device in the order of steps. FIG. 9A to FIG. 9C are views for explaining a conventional method for manufacturing a solid-state imaging device in the order of steps. FIG. 10A to FIG. 10D are diagrams for explaining a conventional method for manufacturing a solid-state imaging device in the order of steps. FIG. 11A to FIG. 11C are diagrams for explaining a conventional method for manufacturing a solid-state imaging device in the order of steps. 12 (a) and 12 (b) are diagrams for explaining a conventional method for manufacturing a solid-state imaging device in the order of steps, and FIG. 12 (b) shows a cross-sectional structure taken along line XIIb-XIIb in FIG. ing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gate oxide film 2 Gate nitride film 3 Gate HTO film | membrane 4 1st Poly-Si (with doping)
5 First interlayer insulating film 6 Second Poly-Si (with doping)
7 Second interlayer insulating film 8 Antireflection film (nitride film)
10 Si substrate 12 Polycrystalline polysilicon 21 Nitride film (after processing on photodiode)
41 First gate electrode 61 Second gate electrode 71 Second interlayer insulating film (on substrate)
81 Anti-reflective coating (after processing)
81a Anti-reflective coating (after etch back)
91 Photoresist pattern for first gate electrode processing 92 Photoresist pattern for second gate electrode processing 93 Photoresist for antireflection film processing 190 Electronic information equipment 191 Imaging unit 192 Memory unit 193 Display unit 194 Communication unit 195 Image output unit

Claims (15)

A method of manufacturing a solid-state imaging device having a plurality of photoelectric conversion units that generate signal charges by photoelectric conversion of incident light, and an antireflection film disposed on each photoelectric conversion unit,
Forming the photoelectric conversion portion on the surface region of the semiconductor substrate and forming a conductor layer on the semiconductor substrate so as to be adjacent to the photoelectric conversion portion;
Forming an antireflection material layer, which is a material of the antireflection film, on the entire surface so that a step of the base is reflected;
Forming a base buried layer having etching selectivity with respect to the antireflection material layer so that a step of the base is embedded on the antireflection material layer;
Etching back the underlying buried layer so that the antireflection material layer on the conductor layer is exposed;
And a step of selectively etching the antireflection material layer so that the antireflection film is formed on the photoelectric conversion portion using the underlying buried layer as a mask. In the manufacturing method of the solid-state imaging device according to claim 1,
In the selective etching process of the antireflection film material, the antireflection material layer remaining under the base buried layer by selective etching of the antireflection film material is removed after the base buried layer is removed. A method of manufacturing a solid-state imaging device, which is processed by etching so as to have a desired thickness. In the manufacturing method of the solid-state imaging device according to claim 2,
The antireflection material layer is
The solid-state imaging device formed so that the distance between the antireflection film disposed on the photoelectric conversion unit and the conductor layer disposed on the semiconductor substrate adjacent to the photoelectric conversion unit is determined by the film thickness. Production method. In the manufacturing method of the solid-state imaging device according to claim 3,
The antireflection material layer is a method for manufacturing a solid-state imaging device having a thickness in a range of 0.2 μm to 0.3 μm. In the manufacturing method of the solid-state imaging device according to claim 4,
The semiconductor substrate is a silicon substrate;
The method for manufacturing a solid-state imaging device, wherein the antireflection material layer is a silicon nitride layer. In the manufacturing method of the solid-state imaging device according to claim 5,
The method for manufacturing a solid-state imaging device, wherein the selective etching of the silicon nitride layer as the antireflection material layer is performed using a fluorine-based etching gas. In the manufacturing method of the solid-state imaging device according to claim 1,
The method for manufacturing a solid-state imaging device, wherein the underlying buried layer is a resist layer formed by applying a resist material over the entire surface. In the manufacturing method of the solid-state imaging device according to claim 7,
The method of manufacturing a solid-state imaging device, wherein the etch back of the resist layer as the underlying buried layer is performed using oxygen gas. In the manufacturing method of the solid-state imaging device according to claim 8,
In the step of etching back the resist layer,
A method of manufacturing a solid-state imaging device that selectively etches only the resist layer. In the manufacturing method of the solid-state imaging device according to claim 9,
The antireflection material layer is a nitride film,
In the step of selectively etching the nitride film as the antireflection material layer using the resist film as the base buried layer as a mask,
A method for manufacturing a solid-state imaging device, wherein the nitride film is etched in a self-aligning manner so that a portion located on the photoelectric conversion portion remains in an island shape using the resist film as a mask. In the manufacturing method of the solid-state imaging device according to claim 10,
A method for manufacturing a solid-state imaging device, comprising: forming the antireflection film by etching the nitride film formed in the island shape so as to have a film thickness of 30 to 70 nm. In the manufacturing method of the solid-state imaging device according to claim 1,
The solid-state imaging device includes a charge transfer unit that transfers a signal charge generated by the photoelectric conversion unit,
The method for manufacturing a solid-state imaging device, wherein the conductor layer constitutes a transfer electrode of the charge transfer unit. In the manufacturing method of the solid-state imaging device according to claim 12,
The method for manufacturing a solid-state imaging device, wherein the conductor layer is made of polysilicon and a silicon oxide film is formed on a surface thereof. In the manufacturing method of the solid-state imaging device according to claim 12,
The transfer electrode constituting the charge transfer portion is made of a first gate electrode made of a first polysilicon layer and a second polysilicon formed on the first polysilicon via an interlayer insulating film. A method for manufacturing a solid-state imaging device including a second gate electrode. An electronic information device including an imaging unit,
An electronic information device using a solid-state imaging device obtained by the method for manufacturing a solid-state imaging device according to claim 1 as the imaging unit.