JP2010118411A - Solid-state image sensor and method of manufacturing the same, and electronic information apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state image sensor in which an area over a photodiode is prevented from being exposed to a plasma; the flexibility in the thickness of a sidewall film used also as a reflection preventing film is enhanced; and the film thickness of the reflection preventing film is optimized despite the deposited film thickness to enhance the responsivity at the photodiode. <P>SOLUTION: A method of manufacturing the solid-state image sensor includes: a sidewall forming step of forming a sidewall on a lateral wall of a gate electrode 6 in a peripheral circuit part 4 by performing the etching while covering a pixel part 3 at least over a photodiode 5 with a resist pattern 11 to leave a laminate film composed of an oxide film 7 and a nitride film 8 on the photodiode 5; and a reflection preventing film forming step of controlling the film thickness of the laminate film composed of an oxide film 7 and a nitride film 8 left on the photodiode 5 as a reflection preventing film. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device configured by a semiconductor element that photoelectrically converts image light from a subject to image and a manufacturing method thereof, for example, a digital video camera using the solid-state imaging device as an image input device in an imaging unit, and The present invention relates to an electronic information device such as a digital camera such as a digital still camera, an image input camera such as a surveillance camera, a scanner device, a facsimile device, a television telephone device, and a mobile phone device with a camera.

  In a conventional solid-state imaging device, for example, a CMOS image sensor or a CCD image sensor, an oxide film or a nitride film for the purpose of preventing light reflection is generally formed on the surface of a semiconductor substrate on a photodiode portion in order to improve light receiving sensitivity. The laminated film is formed as an antireflection film. Since the light-receiving sensitivity characteristic changes depending on the thickness of the anti-reflection film oxide film and nitride film, it is necessary to obtain an optimum finished film thickness.

  In order to form the antireflection film having the optimum film thickness, Patent Documents 1 to 3 propose methods for forming the antireflection film.

  In Patent Document 1, as shown in FIG. 6A, in the conventional solid-state imaging device 100, the gate electrode 101 is formed in the imaging region 111 and the peripheral circuit unit 112, and FIG. 6B and FIG. As shown in FIG. 3, after forming the sidewall 102 on the side wall of the gate electrode 101, the antireflection film 104 is formed only on the surface of the photodiode 103.

  Further, after the salicide 105 is formed only in the peripheral circuit portion 112 around the imaging region 111 as shown in FIG. 6D, the interlayer insulating film 106 formed on the entire surface of the substrate as shown in FIG. 6E. A contact portion 107 is formed on the contact portion 107, and a wiring pattern 108 is formed on the contact portion 107.

  In Patent Document 2, an antireflection film 202 is formed on a photodiode 201 in a conventional solid-state imaging device 200 as shown in FIG.

  Thereafter, as shown in FIG. 7B, a sidewall material film 204 is formed on the entire surface of the substrate including the antireflection film 202 and the gate electrode 203. Subsequently, as shown in FIG. 7C, etching is performed to form a sidewall 205 on the side wall of the gate electrode 203.

  In Patent Document 3, as shown in FIG. 8, in a conventional solid-state imaging device 300, a well region (impurity implantation region) 302 provided on a silicon substrate 301 is formed. First, an element isolation insulating film 303 is formed above the well region 302, and a photodiode formation region 304 and a pixel transistor formation region 305 are provided in the region isolated by the element isolation insulating film 303. ing.

  The photodiode formation region 304 is provided with impurity implantation regions 306 and 307 constituting an embedded photodiode, and the pixel transistor formation region 305 is formed with an impurity implantation region 308 for forming an LDD and source / drain formation. An impurity implantation region 309 is provided for this purpose.

  In addition, insulating films M1 to M5 are disposed on the upper surface of the silicon substrate 301, a gate electrode 310 of a MOS transistor is formed on the gate insulating film M1, and an insulating film serving as a sidewall is formed on the side thereof. M2, M3 and M5 are arranged. A planarizing film 311 is disposed on the interlayer insulating film M4, and a color filter and an on-chip microlens (not shown) are disposed on the planarizing film 311.

The solid-state imaging device 300 includes a transistor using a sidewall made of a three-layer film of insulating films M2, M3, and M5. By using the above-described four-layered film (gate insulating film M1, insulating films M2, M3, and M4) as the insulating film on the photodiode, the solid-state imaging device 300 having good transistor characteristics and high photoelectric conversion efficiency can be obtained. Can do.
Japanese Patent Laid-Open No. 2001-111022 JP 2002-83949 A JP 2005-340475 A

  However, each of Patent Documents 1 to 3 has drawbacks as described below.

  In Patent Document 1, as shown in FIGS. 6B and 6C, when the sidewall 102 of the gate electrode 101 is formed, plasma etching is performed on the entire surface of the substrate. The surface is exposed to plasma etching, and the surface on the photodiode 103 is damaged, resulting in a great influence on the pixel characteristics.

  In Patent Document 2, since the sidewall 205 is formed after the antireflection film 202 is formed on the photodiode 201 as shown in FIGS. Although the surface of the photodiode 201 protected by the antireflection film 202 is not affected by plasma damage due to etching, the antireflection film 202 is etched when the sidewalls 205 are formed, so that the antireflection film 202 performs its function. However, the film thickness of the antireflection film 202 is reduced although the film thickness needs to be optimized.

  In addition, isotropic etching (wet etching) is indispensable in order not to leave the antireflection film in a sidewall shape on the side wall of the gate electrode 203 at the time of etching when forming the antireflection film 201, and the pattern processing accuracy In addition, there is a concern that the gate oxide film under the gate electrode 203 is side-etched and bites under the gate electrode 203 to have a notch in the gate oxide film.

  In Patent Document 3, as shown in FIG. 8, an antireflection film is formed on the photodiode so that the photodiode is not exposed to plasma, and the antireflection film is reduced in the middle process. The deposition thickness of the antireflection film is determined so that the film thickness of the antireflection film becomes an optimum film thickness. However, since the interlayer insulating film M4 (PSIN) is required to be 40 nm or more as a contact stopper and the optimum nitride film thickness is required to be 50 nm or more, the deposited film thickness of the insulating film M3 (LPSiN) for forming the sidewall is almost equal. It will be decided. In order to avoid this, a step of removing the side wall of the pixel portion is necessary.

  The present invention solves the above-mentioned conventional problems, avoids exposure to plasma on the photodiode, increases the degree of freedom of the sidewall film thickness that is also used as an antireflection film, and reflects regardless of the deposition film thickness. A solid-state imaging device capable of optimizing the film thickness of the prevention film and improving the light receiving sensitivity of the photodiode, and a manufacturing method thereof, for example, a camera using the solid-state imaging device as an image input device in an imaging unit It is an object of the present invention to provide an electronic information device such as a mobile phone device with a telephone.

  In the solid-state imaging device manufacturing method of the present invention, a peripheral circuit unit having a plurality of transistors is provided around an imaging region in which a plurality of light receiving units that photoelectrically convert image light from a subject are two-dimensionally arranged. In the method of manufacturing a solid-state imaging device, when forming a sidewall on the sidewall of the gate electrode of the transistor, at least the light receiving portion is covered with a resist pattern and etched to form one or more films on the light receiving portion. The method includes a sidewall forming step to be left and an antireflection film forming step for adjusting the film thickness of one or a plurality of films left on the light receiving portion as an antireflection film, thereby achieving the above object.

  Preferably, in the method for manufacturing a solid-state imaging device according to the present invention, the sidewall forming step includes a semiconductor substrate on which the plurality of light receiving portions, a gate electrode for reading signal charges of the light receiving portions, and a gate electrode of the transistor are formed. One or a plurality of film forming steps for forming one or a plurality of films for forming a sidewall on the entire surface of the semiconductor layer, and a part of or all of the signal charge readout gate electrode from above the light receiving portion only A first resist pattern forming step for forming a first resist pattern so as to cover the first resist pattern, and etching using the first resist pattern as a mask, from a part or all of the signal charge reading gate electrode onto the light receiving portion; And an etching step of forming a sidewall on the sidewall of the gate electrode of the transistor while leaving one or a plurality of films.

  Further preferably, it has a salicide step between the sidewall formation step and the antireflection film formation step in the method for manufacturing a solid-state imaging device of the present invention, and the salicide step is a semiconductor substrate after the formation of the sidewall. Alternatively, a salicide mask film forming step of forming a salicide mask film on the entire surface of the semiconductor layer, a second resist pattern forming step of forming a second resist pattern only on the imaging region, and using the second resist pattern as a mask A salicide mask film removing step for removing the salicide mask film only in the peripheral circuit portion by etching, and a salicide for forming salicide on the gate electrode and the source / drain region of the transistor in the peripheral circuit portion from which the salicide mask film has been removed. Forming step.

  Further preferably, the antireflection film forming step in the method for manufacturing a solid-state imaging device of the present invention includes forming a contact stopper film on the entire surface of the semiconductor substrate or semiconductor layer on which the salicide is formed. And a third resist pattern forming step of forming a third resist pattern so that the light receiving portion opens from a part or all of the gate electrode of the pixel portion, and etching using the third resist pattern as a mask. And an antireflection film optimum film thickness forming step of removing the salicide mask film from the contact stopper film and further forming the antireflection film to an optimum film thickness.

  Further preferably, the antireflection film forming step in the method for manufacturing a solid-state imaging device of the present invention comprises forming a contact stopper film on the entire surface of the semiconductor substrate or semiconductor layer after the formation of the sidewall. A film process; a third resist pattern forming process for forming a third resist pattern so that the light receiving part opens from a part or all of the gate electrode of the pixel part; and etching using the third resist pattern as a mask. And an antireflection film optimum film thickness forming step of removing the contact stopper film and further forming the antireflection film to an optimum film thickness.

  Further preferably, the material film of the antireflection film in the method for producing a solid-state imaging device of the present invention is also used as the material film of the sidewall.

  Further preferably, the antireflection film in the method for manufacturing a solid-state imaging device of the present invention is composed of a laminated film of an oxide film and a nitride film.

  The solid-state imaging device of the present invention is a solid-state imaging device manufactured by the manufacturing method of the solid-state imaging device of the present invention, and in the imaging region, one side of the cross-sectional side wall of the gate electrode for signal charge readout is provided. Alternatively, a sidewall made of a plurality of films is formed, and the sidewall is formed on a part of the gate electrode left on the light receiving portion via the other side of the sectional side wall of the gate electrode. One or a plurality of films are adjusted to an optimum film thickness as an antireflection film, and in the peripheral circuit portion, side walls made of the one or a plurality of films are formed on both sides of a cross-sectional side wall of the gate electrode of the transistor. This achieves the above object.

  Preferably, in the imaging region of the solid-state imaging device of the present invention, a salicide mask film and a contact stopper film thereon are formed on one side of the cross-sectional side wall from a part or all of the signal charge readout gate electrode. At least the contact stopper film is provided, and the contact stopper film is provided on the gate electrode of the transistor and on the peripheral circuit portion including both sides of the cross-sectional side wall.

  The electronic information device of the present invention uses the solid-state imaging device of the present invention as an image input device in an imaging unit, and thereby achieves the above object.

  With the above configuration, the operation of the present invention will be described below.

  In the method for manufacturing a solid-state imaging device according to the present invention, when forming a sidewall on the sidewall of the gate electrode of a transistor, the side that leaves one or more films on the light receiving portion is formed by covering the light receiving portion with a resist pattern and etching. A wall forming step, and an antireflection film forming step of adjusting the film thickness using one or a plurality of films left on the light receiving portion as an antireflection film.

  In this case, since the thickness of the sidewall is larger than that of the antireflection film, when the sidewall is formed first, the light receiving portion is covered with a resist pattern and etched, and remains under the resist pattern. One or more films are used as an antireflection film, and the film thickness is reduced later to optimize the film thickness of the antireflection film.

  On the other hand, in Patent Document 3, each of the sidewalls and the antireflection film is considered in consideration of film thickness reduction so that the thicknesses of the sidewalls having different thicknesses and the thickness of the antireflection film are optimized first. Since the film thickness is determined, the degree of freedom of the sidewall film thickness that is also used as the antireflection film is narrowed, and it is difficult to finally form each film thickness of the sidewall and the antireflection film accurately. It was.

  On the other hand, in the present invention, as described above, when the sidewall is formed, the light receiving portion is covered with a resist pattern and etched, so that the light receiving portion is not exposed to plasma, and an antireflection film is formed later. By optimizing the film thickness by reducing the film thickness, it is possible to increase the degree of freedom of the sidewall film thickness that is also used as the antireflection film, and finally the antireflection film regardless of the deposition film thickness. The film thickness can be easily optimized.

  As described above, according to the present invention, when the sidewall is formed, the light receiving portion is covered with a resist pattern and etched, and the film remaining under the resist pattern is used as an antireflection film, and the film thickness of the antireflection film is adjusted later. Therefore, it is possible to optimize the film thickness of the antireflection film regardless of the deposition film thickness so that the light receiving part is not exposed to plasma, the degree of freedom of the side wall film thickness to be combined with the antireflection film is increased. As a result, the light receiving sensitivity at the light receiving unit can be improved.

  In short, it is only necessary to reduce the film thickness so that the final thickness of the anti-reflection film is optimized, so that a more accurate optimized film thickness of the anti-reflection film can be easily obtained, and light reception at the light receiving unit is possible. Sensitivity can be further improved.

  Hereinafter, Embodiment 1 of the solid-state imaging device and the manufacturing method thereof according to the present invention and implementation of an electronic information device such as a mobile phone device with a camera using Embodiment 1 of the solid-state imaging device as an image input device in an imaging unit will be described below. Form 2 will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a longitudinal cross-sectional view illustrating an exemplary configuration of a main part of a solid-state imaging device according to Embodiment 1 of the present invention.

  In FIG. 1, a solid-state imaging device 1 according to the first embodiment is an imaging region in which a large number of unit pixels (a plurality of light receiving units) are arranged on a semiconductor substrate 2 (or a semiconductor region provided on the substrate). A pixel unit 3 is provided, and a peripheral circuit unit 4 that constitutes a controller that outputs a control signal for reading signals from each unit pixel is provided around the pixel unit 3. In short, the peripheral circuit unit 4 having a plurality of transistors is provided around the pixel unit 3 that is an imaging region in which a plurality of light receiving units that photoelectrically convert image light from a subject is disposed.

  In the pixel unit 3, a plurality of photodiodes 5 serving as a plurality of light receiving units that photoelectrically convert image light from a subject to be imaged are arranged in a two-dimensional matrix, and the subject light is photoelectrically converted by the photodiode 5. A gate electrode 6 for reading signal charges is provided adjacent to the photodiode 5. Further, the peripheral circuit portion 4 around the pixel portion 3 is also provided with gate electrodes 6 of a plurality of transistors constituting the circuit.

  In the pixel portion 3, a side wall made of an oxide film 7 and a nitride film 8 is formed on one side of the cross-sectional side wall of the gate electrode 6 for reading signal charges. On the diode 5, the oxide film 7 and the nitride film 8 constituting the sidewall are left, and the nitride film 8 and the oxide film 7 are controlled to an optimum film thickness (thickness adjustment) as an antireflection film. By using the remaining film 8a and the oxide film 7, the light receiving sensitivity of the photodiode 5 is improved.

  In the peripheral circuit portion 4, side walls made of the oxide film 7 and the nitride film 8 are formed on both sides of the cross-sectional side wall of the gate electrode 6.

  The controller of the peripheral circuit unit 4 includes a logic circuit, a shift register circuit, a driver circuit, a clock circuit, and the like. The peripheral circuit unit 4 may include a DSP of the control unit.

Next, the manufacturing method of the solid-state imaging device according to the first embodiment will be described more specifically with reference to FIGS.
2 (a) to 2 (c), 3 (a) to 3 (c), and 4 (a) to 4 (c) are diagrams of the solid-state imaging device according to the first embodiment of the present invention. It is a principal part longitudinal cross-sectional view for demonstrating each manufacturing process to an antireflection film formation process.

  First, in the sidewall forming step, as shown in FIG. 2A, an oxide film 7A and a nitride film 8A for forming a sidewall are formed on the entire surface of the semiconductor substrate 2 on which the photodiode 5 and the gate electrode 6 are formed. Are formed in this order. For example, the oxide film 7A has a thickness of 10 to 30 nm, and the nitride film 8A has a thickness of 40 to 110 nm. Further, as shown in FIG. 2B, a resist pattern 11 is formed so as to cover the photodiode 5. Further, as shown in FIG. 2C, etching is performed using the resist pattern 11 as a mask to form a sidewall on the sidewall of the gate electrode 6 by the oxide film 7 and the nitride film 8, and further ashing is performed to form a resist pattern. 11 peeling process is implemented. An oxide film 7 and a nitride film 8 used as an antireflection film remain on the photodiode 5.

  As described above, in the side wall formation process of FIGS. 2A to 2C, a plurality of light receiving portions (photodiodes 5) are provided on the semiconductor substrate 2 (or the semiconductor layer), and pixels from which signal charges of the light receiving portions are read out. An oxide film 7A and a nitride film as a plurality of insulating films (or a single insulating film) for forming sidewalls on the entire surface of the substrate on which the gate electrode 6 of the portion 3 and the gate electrode 6 of the transistor of the peripheral circuit portion 4 are formed Insulating film forming step for forming 8A, and a first resist for forming a first resist pattern (resist pattern 11) so as to cover only the light receiving portion (photodiode 5) from the gate electrode 6 for reading signal charges A pattern forming step and an etching step of etching using the first resist pattern as a mask.

  Next, in the salicide process, as shown in FIG. 3A, an oxide film 9A as a salicide mask film is formed on the entire surface of the substrate. Further, as shown in FIG. 3B, a resist pattern 12 is formed only in the imaging region of the pixel portion 3 on the oxide film 9A. Further, as shown in FIG. 3C, etching is performed using the resist pattern 12 as a mask to remove the oxide film 9A only in the peripheral circuit portion 4, and ashing is performed, and the resist pattern 12 is peeled off.

  As a result, the oxide film 9 remains as a salicide mask only in the pixel portion 3 as the imaging region. Thereafter, the salicide 14 is formed in the gate electrode, source region, and drain region of the transistor of the peripheral circuit portion 4.

  As described above, in the salicide process of FIGS. 3A to 3C, the salicide mask film forming process for forming the oxide film 9A as the salicide mask film on the entire surface of the semiconductor substrate 2 (or the semiconductor layer); A second resist pattern forming step of forming a resist pattern 12 as a second resist pattern only on the pixel portion 3 that is the imaging region, and an oxide film only on the peripheral circuit portion 4 by etching using the resist pattern 12 as a mask A salicide mask film removing step for removing 9A, and a salicide forming step for forming salicide 14 in the gate electrode 6 and source / drain regions of each transistor of the peripheral circuit portion 4 from which the oxide film 9A has been removed. .

  Subsequently, in the antireflection film forming step, as shown in FIG. 4A, a nitride film 10A such as a plasma SiN film for contact stopper is formed on the entire surface of the substrate. For example, the nitride film 10A is formed to have a thickness of 40 to 60 nm. Further, as shown in FIG. 4B, a resist pattern 13 is formed so that the top of the photodiode 5 is opened.

  Further, as shown in FIG. 4C, dry etching is performed using the resist pattern 13 as a mask, the nitride film 10A is removed in order to improve light collection, and a part of the nitride film 8 is further removed, and ashing is performed. Then, the resist pattern 13 is peeled off. This dry etching is performed so that the remaining film 8a of the nitride film 8 on the photodiode 5 has a film thickness of 40 to 70 nm. As a result, the antireflection film composed of the oxide film 7 and the nitride film 8a can be formed to an optimum film thickness.

  4A to 4C, the anti-reflection film forming step forms the nitride film 10A as the contact stopper film on the entire surface of the semiconductor substrate 2 (or semiconductor layer). A film forming step, a third resist pattern forming step for forming a resist pattern 13 as a third resist pattern so that the photodiode 5 is opened from a part or all of the gate electrode 6 of the pixel portion 3, and the resist Etching using the pattern 13 as a mask, the nitride film 10A on the photodiode 5 is removed, and further, a part of the nitride film 8 is removed from the oxide film 7 and the nitride film 8 serving as an antireflection film, and the oxide film 7 and And an antireflection film optimum film thickness forming step for forming an optimum film thickness of the nitride film 8a.

  As described above, in the method for manufacturing the solid-state imaging device 1 according to the first embodiment, the oxide film 7 and the nitride film 8 are formed on the photodiode 5 by etching the photodiode 5 while covering the photodiode 5 with the resist pattern 11 when the sidewall is formed. Is leaving. Etching using the resist pattern 13 opens the photodiode 5 and etches the surface portion of the nitride film 8 constituting a part of the antireflection film so that the film thickness is optimum as the antireflection film. ing. The remaining oxide film 7 and nitride film 8a are used as an antireflection film for the photodiode 5.

  As described above, in the first embodiment, when the sidewall is formed on the sidewall of the gate electrode 6 of the transistor, the photodiode 5 is covered with the resist pattern 11 and etched, so that one or the other is formed on the photodiode 5. The side wall forming step for leaving a plurality of films (here, oxide film 7 and nitride film 8) and one or a plurality of films (here, oxide film 7 and nitride film 8) left on photodiode 5 are used as antireflection films. And an antireflection film forming step to be adjusted. In this case, since the thickness of the sidewall is thicker than the thickness of the antireflection film, when the sidewall is formed first, the photodiode 5 is covered with the resist pattern 11 and etched. One or a plurality of remaining films (here, the oxide film 7 and the nitride film 8) are used as an antireflection film, and the film thickness is reduced later to optimize the film thickness of the antireflection film.

  That is, in order to prevent deterioration of pixel characteristics due to etching plasma damage to the surface portion on the photodiode 5 when the sidewall is formed, in the present invention, as described above, on the photodiode 5 when the sidewall is formed. Is covered with a resist pattern 11 and etched, and the remaining oxide film 7 and nitride film 8 are used as an antireflection film.

  As a result, the photodiode 5 is not exposed to plasma, the degree of freedom of the sidewall film thickness that is also used as the antireflection film is increased, and the film thickness of the antireflection film is optimized regardless of the deposition film thickness, The light receiving sensitivity at the photodiode 5 can be improved.

  Further, if the adjustment is made by the sidewall deposition film thickness in order to set the optimum light receiving sensitivity, the film thickness is almost determined, and in order to avoid this, a step of removing the sidewall of the pixel unit 3 is necessary. Therefore, in the first embodiment, by forming the antireflection film on the photodiode 5 and then performing partial etching, the antireflection film is made an optimum remaining film, thereby providing a degree of freedom in the deposition film thickness. There is no rule in film thickness. Because of partial etching, even if dry etching is used, plasma damage on the photodiode 5 is not easily received.

  Although not particularly described in the first embodiment, when forming a sidewall on the sidewall of the gate electrode 6 of the transistor, at least the light receiving portion is covered with the resist pattern 11 and etched, thereby etching the photodiode 5. A sidewall forming step for leaving one or a plurality of films on the substrate 5 and an antireflection film forming step for adjusting the film thickness using the one or a plurality of films remaining on the photodiode 5 as an antireflection film.

  In short, when forming a sidewall on the side wall of the gate electrode 6 of the peripheral circuit portion 4, the oxide film 7 and the photodiode 5 are formed on the photodiode 5 by etching at least the photodiode 5 of the pixel portion 3 with the resist pattern 11. A sidewall forming step for leaving the laminated film of the nitride film 8, and an antireflection film forming step for adjusting the film thickness using the laminated film of the oxide film 7 and the nitride film 8 left on the photodiode 5 as an antireflective film. Then, when the sidewall is formed, the light receiving portion is covered with the resist pattern 11 and etched, and the film remaining under the resist pattern 11 can be used as an antireflection film so that the film thickness of the antireflection film can be adjusted later. Do not expose the surface to plasma, increase the degree of freedom of the sidewall film thickness that is also used as an antireflection film, and reflect regardless of the deposition film thickness Able to optimize the thickness of the sealing film, it is possible to improve the light receiving sensitivity of the light receiving portion. In short, it is only necessary to reduce the film thickness so that the final thickness of the anti-reflection film is optimized, so that a more accurate optimized film thickness of the anti-reflection film can be easily obtained, and light reception at the light receiving unit is possible. Sensitivity can be further improved.

  Therefore, the upper surface of the photodiode 5 is not exposed to plasma, the degree of freedom of the sidewall film thickness that is also used as the antireflection film is increased, and the film thickness of the antireflection film is optimized regardless of the deposition film thickness. The object of the present invention that can improve the light receiving sensitivity of the diode 5 can be achieved.

In this case, unlike the first embodiment, the salicide process is not provided between the sidewall formation process and the antireflection film formation process, and the antireflection film formation process is performed in the semiconductor substrate 2 (or semiconductor layer) after the formation of the sidewalls. A contact stopper film forming step for forming a contact stopper film on the entire surface, and a third resist pattern as an opening on the photodiode 5 from a part or all of the gate electrode 6 of the pixel portion 3. The third resist pattern forming step for forming the resist pattern 13, and etching using the resist pattern 13 as a mask to remove the contact stopper film, and further to form the antireflection film at the optimum film thickness Forming step.
(Embodiment 2)
FIG. 5 is a block diagram illustrating a schematic configuration example of an electronic information device using, as an imaging unit, a solid-state imaging device including the solid-state imaging device 1 according to the first embodiment of the present invention as the second embodiment of the present invention.

  In FIG. 5, an electronic information device 90 according to the second embodiment includes a solid-state imaging device 91 that obtains a color image signal by performing various signal processing on the imaging signal from the solid-state imaging device 1 according to the first embodiment, and the solid-state imaging device 91. A memory unit 92 such as a recording medium that can record data after a predetermined signal processing for recording a color image signal from the recording medium, and a liquid crystal after a predetermined signal processing for display of the color image signal from the solid-state imaging device 91 Display means 93 such as a liquid crystal display device which can be displayed on a display screen such as a display screen, and a transmission / reception device which can perform communication processing after performing predetermined signal processing for color image signals from the solid-state imaging device 91 for communication Communication means 94 such as a printer and the like, and a color image signal from the solid-state image pickup device 91 and an image output such as a printer that can perform print processing after performing predetermined print signal processing for printing. And a means 74.

  The electronic information device 90 is not limited to this, but in addition to the solid-state imaging device 91, at least one of a memory unit 92, a display unit 93, a communication unit 94, and an image output unit 95 such as a printer. You may have.

  As described above, the electronic information device 90 includes, for example, a digital camera such as a digital video camera and a digital still camera, an in-vehicle camera such as a surveillance camera, a door phone camera, and an in-vehicle rear surveillance camera, and a video phone camera. An electronic device having an image input device such as an image input camera, a scanner device, a facsimile device, a camera-equipped mobile phone device, and a portable terminal device (PDA) is conceivable.

  Therefore, according to the second embodiment, on the basis of the color image signal from the solid-state imaging device 91, it is displayed on the display screen, or is printed out on the paper by the image output means 95. (Printing), communicating this as communication data in a wired or wireless manner, performing a predetermined data compression process in the memory unit 92 and storing it in a good manner, or performing various data processings satisfactorily Can do.

  As mentioned above, although this invention was illustrated using preferable Embodiment 1, 2 of this invention, this invention should not be limited and limited to this Embodiment 1,2. 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 1 and 2 of the present invention. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  The present invention relates to a solid-state imaging device configured by a semiconductor element that photoelectrically converts image light from a subject to image and a manufacturing method thereof, for example, a digital video camera using the solid-state imaging device as an image input device in an imaging unit, and In the field of electronic information equipment such as digital cameras such as digital still cameras, image input cameras such as surveillance cameras, scanner devices, facsimile devices, television telephone devices, and mobile phone devices with cameras, Is covered with a resist pattern and etched, and the film remaining under the resist pattern is used as an antireflection film, and the film thickness of the antireflection film is adjusted later. Increase the degree of freedom of the sidewall film thickness that can be combined with the anti-reflection film regardless of the deposition film thickness. Able to optimize the thickness, it is possible to improve the light receiving sensitivity of the light receiving portion. In short, it is only necessary to reduce the film thickness so that the final thickness of the anti-reflection film is optimized, so that a more accurate optimized film thickness of the anti-reflection film can be easily obtained, and light reception at the light receiving unit is possible. Sensitivity can be further improved.

It is a longitudinal cross-sectional view which shows the principal part structural example of the solid-state image sensor which concerns on Embodiment 1 of this invention. (A)-(c) is a principal part longitudinal cross-sectional view for demonstrating the sidewall formation process in each manufacturing process to the anti-reflective film formation process of the solid-state image sensor which concerns on Embodiment 1 of this invention. (A)-(c) is a principal part longitudinal cross-sectional view for demonstrating the salicide process in each manufacturing process to the anti-reflective film formation process of the solid-state image sensor which concerns on Embodiment 1 of this invention. (A)-(c) is a principal part longitudinal cross-sectional view for demonstrating the antireflection film optimal film thickness formation process in each manufacturing process to the antireflection film formation process of the solid-state image sensor concerning Embodiment 1 of this invention. It is. It is a block diagram which shows the schematic structural example of the electronic information apparatus which used the solid-state imaging device containing the solid-state image sensor 1 of Embodiment 1 of this invention for Embodiment 2 of this invention for the imaging part. (A)-(e) is a principal part longitudinal cross-sectional view for demonstrating each manufacturing process of the conventional solid-state image sensor currently disclosed by patent document 1. FIG. (A)-(d) is a principal part longitudinal cross-sectional view for demonstrating each manufacturing process of the conventional solid-state image sensor currently disclosed by patent document 2. FIG. It is a longitudinal cross-sectional view which shows the example of a principal part structure of the conventional solid-state image sensor currently disclosed by patent document 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid-state image sensor 2 Semiconductor substrate 3 Pixel part 4 Peripheral circuit part 5 Photodiode 6 Gate electrode 7, 9 Oxide film 8, 10 Nitride film 8a Residual film 11-13 Resist pattern 90 Electronic information equipment 91 Solid-state imaging device 92 Memory part 93 Display means 94 Communication means 95 Image output means

Claims (10)

In a method of manufacturing a solid-state imaging device in which a peripheral circuit unit having a plurality of transistors is provided around an imaging region in which a plurality of light receiving units that photoelectrically convert image light from a subject are two-dimensionally arranged.
When forming a sidewall on the side wall of the gate electrode of the transistor, a sidewall forming step of leaving one or a plurality of films on the light receiving portion by covering and etching at least the light receiving portion with a resist pattern;
A method of manufacturing a solid-state imaging device, comprising: an antireflection film forming step of adjusting film thickness using one or a plurality of films left on the light receiving portion as an antireflection film. The sidewall forming step includes
One or more films for forming sidewalls are formed on the entire surface of the semiconductor substrate or semiconductor layer on which the plurality of light receiving portions, the gate electrode for reading signal charges of the light receiving portions, and the gate electrode of the transistor are formed. Or multiple film deposition step;
A first resist pattern forming step of forming a first resist pattern so as to cover only the light receiving portion from a part or all of the gate electrode for reading signal charges;
Etching using the first resist pattern as a mask, leaving one or a plurality of films on the light receiving portion from a part or all of the gate electrode for reading the signal charge, and a sidewall on the side wall of the gate electrode of the transistor The manufacturing method of the solid-state image sensor of Claim 1 which has an etching process which forms. There is a salicide process between the sidewall forming process and the antireflection film forming process, and the salicide process includes:
A salicide mask film forming step of forming a salicide mask film on the entire surface of the semiconductor substrate or semiconductor layer after the formation of the sidewall; and
A second resist pattern forming step of forming a second resist pattern only on the imaging region;
A salicide mask film removing step of removing the salicide mask film only in the peripheral circuit portion by etching using the second resist pattern as a mask;
3. The method of manufacturing a solid-state imaging device according to claim 2, further comprising a salicide forming step of forming salicide on the gate electrode and the source / drain region of the transistor in the peripheral circuit portion from which the salicide mask film has been removed. The antireflection film forming step includes:
A contact stopper film forming step of forming a contact stopper film on the entire surface of the semiconductor substrate or semiconductor layer on which the salicide is formed;
A third resist pattern forming step of forming a third resist pattern so that the light receiving part is opened from a part or all of the gate electrode of the pixel part;
And etching the third resist pattern as a mask, removing the contact stopper film and the salicide mask film, and further forming an antireflection film optimum film thickness forming step for forming the antireflection film to an optimum film thickness. Item 4. A method for manufacturing a solid-state imaging device according to Item 3. The antireflection film forming step includes:
A contact stopper film forming step of forming a contact stopper film on the entire surface of the semiconductor substrate or semiconductor layer after the formation of the sidewall;
A third resist pattern forming step of forming a third resist pattern so that the light receiving part is opened from a part or all of the gate electrode of the pixel part;
3. The method according to claim 1, further comprising: an etching process using the third resist pattern as a mask to remove the contact stopper film, and further forming an antireflection film optimum film thickness step for forming the antireflection film to an optimum film thickness. The manufacturing method of the solid-state image sensor of description.   The method for manufacturing a solid-state imaging device according to claim 1, wherein the material film of the antireflection film is also used as the material film of the sidewall.   The method for manufacturing a solid-state imaging device according to claim 1, wherein the antireflection film is formed of a laminated film of an oxide film and a nitride film. A solid-state imaging device manufactured by the method for manufacturing a solid-state imaging device according to claim 1,
In the imaging region, a side wall made of one or a plurality of films is formed on one side of the cross-sectional side wall of the gate electrode for signal charge readout, and the cross-sectional side wall of the gate electrode is formed from a part or all of the gate electrode. One or more films constituting the sidewall left on the light receiving part via the other side of the film are adjusted to an optimum film thickness as an antireflection film,
In the peripheral circuit portion, a solid-state imaging device in which sidewalls made of one or a plurality of films are formed on both sides of a sectional sidewall of the gate electrode of the transistor. In the imaging region, at least one of the salicide mask film and the contact stopper film thereon is provided on one side of the sectional side wall from a part or all of the signal charge readout gate electrode. ,
The solid-state imaging device according to claim 8, wherein the contact stopper film is provided on the gate electrode of the transistor and on the peripheral circuit portion including both sides of the cross-sectional side wall.   An electronic information device using the solid-state imaging device according to claim 8 as an image input device in an imaging unit.

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