JP2010114227A - Solid imaging device and method of manufacturing the same, and electronic information apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a manufacturing process without forming a contact part as in the prior art, and also form a concave shape having an advantageous efficiency of light collection without shape variations. <P>SOLUTION: Transfer electrodes 4 of a first layer are coupled to each other in the line direction to form a plurality of T-forms and transfer electrodes 5 of a second layer are coupled to each other in the line direction to form a plurality of inverted T-forms. The transfer electrodes 4 of the first layer are superposed on the transfer electrodes 5 of the second layer in the line direction so that ends of the transfer electrodes 4 of the first layer projected between the lines are superposed on ends of the transfer electrodes 5 of the second layer projected between the lines. In regions over the transfer electrodes 5 of the second layer where the transfer electrodes 5 of the second layer are not superposed on the transfer electrodes 4 of the first layer, in areas smaller than the transfer electrodes 5 of the second layer (having a smaller width), columnar island-shaped dummy structures 6 (dummy films) are arranged. <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.

  A conventional CCD solid-state imaging device has a plurality of photoelectric conversion elements composed of a plurality of light receiving portions arranged in a matrix on a light receiving surface, and a vertical CCD arranged on at least one side of the photoelectric conversion elements, Transfer electrodes are arranged for applying a drive pulse to the vertical CCD to transfer signal charges in the vertical direction. Furthermore, an electrode material is used as a wiring for the transfer electrode between the light receiving portions adjacent in the row direction. On top of this, an interlayer insulating film, a light shielding shielding film, and an interlayer insulating film are arranged in this order, and the surface of the interlayer insulating film has a concave shape above the light receiving portion. When the concave portion is inclined in the X direction and Y direction in a plan view and the surface thereof is inclined at the same angle in the longitudinal section, a stable lens effect is obtained and the light collection rate is increased, and the light receiving sensitivity at the light receiving portion. Therefore, it is possible to obtain a solid-state imaging device having a high value.

  In addition, when a part of the first-layer transfer electrode and the second-layer transfer electrode are overlapped with each other in the vertical vertical CCD adjacent to each light-receiving portion in the column direction, the height of this part does not overlap. It differs from the height of the single layer structure of the second layer transfer electrode. Further, the wiring to the transfer electrodes adjacent in the horizontal direction has a wiring structure in which the first-layer and second-layer transfer electrodes overlap. For this reason, the concave surface slope of the interlayer insulating film disposed on the upper part of the light receiving portion has different angles in the X direction and the Y direction, so that a stable lens effect cannot be obtained, and the incident light is not collected into the pixel portion. Light efficiency decreases. For this reason, when each light receiving part is reduced with an increase in the number of pixels, the light receiving sensitivity is further lowered.

  Patent Document 1 discloses a method for improving the light collection efficiency of incident light to the pixel portion.

  FIG. 10 is a plan view showing the main part of the imaging region of the conventional solid-state imaging device disclosed in Patent Document 1 and its electrode pattern. This shows a transfer electrode pattern on the vertical transfer register for transferring the signal charge received by the light receiving unit in the vertical direction.

  As shown in FIG. 10, in the conventional solid-state imaging device 100, in the vertical direction portion along the charge transfer path of the vertical transfer register 101, the transfer electrode 102 and the transfer electrode 103 that also serves as the readout electrode are alternately adjacent to each other. Is arranged. A transfer electrode 102 made of a polycrystalline silicon layer and a transfer electrode 103 serving also as a readout electrode are arranged so as to be alternately repeated in the charge transfer direction, that is, the vertical direction.

  The transfer electrode 102 is provided in the vertical transfer register 101 so as to avoid the light receiving part 104 and the edge part 102a provided so as to be close to the transfer electrode 103 that also serves as an adjacent readout electrode along the charge transfer path. The edge portion 102b and the edge portion 102c provided on the opposite side of the edge portions 102a and 102b are formed. That is, the transfer electrode 102 is provided to extend between the light receiving portions 104 (pixels) adjacent in the vertical direction, and the transfer electrodes 102 for each line (row) arranged in each vertical transfer register 101 are integrated. So as to be connected to each other.

  On the other hand, the transfer electrode 103 that also serves as the readout electrode is formed so as to be disposed on the vertical transfer register 101 between the light receiving units 104 adjacent to the left and right, and is close to the transfer electrode 102 adjacent in the charge transfer direction. It is formed so as to have an edge portion 103a at one end and an edge portion 103b at the other end. The edge portion 103a is formed so as to face and approach the edge portion 102a of the transfer electrode 102, and the edge portion 103b is formed so as to face and approach the edge portion 102c of the transfer electrode 102. The edge portion 103a and the edge portion 102a, and the edge portion 103b and the edge portion 102c are formed to have a predetermined distance from each other. That is, the transfer electrode 103 that also serves as the readout electrode is formed in a separated state without being connected to any electrode, as shown in the Y2 direction sectional view of FIG. It is formed as an electrode.

  An extension portion is formed on the transfer electrode 102 in the vertical transfer register 101 so as to face the transfer electrode 103. The horizontal width W1 of the extension is formed to be the same width as the horizontal width W2 of the opposing transfer electrode 103. The horizontal widths W1 and W2 of the transfer electrodes 102 and 103 existing on the same vertical transfer register 101 are formed to have the same width. As described above, by aligning the horizontal widths of the transfer electrodes 102 and 103 arranged on the same vertical transfer register 101, the signal charges in the vertical transfer register 101 can be transferred more efficiently. .

  Further, the shape of the transfer electrode 103 on the same vertical transfer register 101 is formed to be the same as the shape of the other transfer electrodes 103. In this way, by aligning the shapes of the transfer electrodes 102 and 103 on the vertical transfer register 101, the signal charges in the vertical transfer register 101 can be transferred more efficiently.

  On the transfer electrode 102 provided between the light receiving portions 104 adjacent in the vertical direction, a shunt wiring 105 made of, for example, polycrystalline silicon made of a material having a low resistance is formed in the horizontal direction. Yes. A part of the shunt wiring 105 is extended in the vertical direction, and an extension portion 105a is formed so as to extend on each transfer electrode 103 that also serves as a readout electrode. A contact portion 106 is formed on the extension portion 105a. In the contact portion 106, the shunt wiring 105 is connected to the transfer electrode 103 via a contact hole provided in the interlayer insulating film.

  The vertical width W3 of the shunt wiring 105 is formed to be narrower than the vertical width W1 of the transfer electrode 102. Further, the extension portion 105 a of the shunt wiring 105 extending on the transfer electrode 103 is formed such that the horizontal width W <b> 3 is smaller than the horizontal width W <b> 2 of the transfer electrode 103.

  When the signal charges accumulated in the light receiving unit 104 are read to the vertical transfer register 101, the signal charges read to the vertical transfer register 101 are driven by four-phase drive pulses φ1 to φ4 applied to the transfer electrodes 102 and 103. Charges are transferred in the vertical transfer register 101.

  As described above, the conventional solid-state imaging device 100 disclosed in Patent Document 1 has an oxide film disposed on the first transfer electrode 103 as shown in the X-direction cross-sectional view of FIG. Further, a contact portion 106 is formed, a shunt wiring material is formed as the shunt wiring 105 of the second-layer polysilicon film, and these are arranged on the transfer electrode 103 of the first layer. By adopting this laminated shape, the concave portion 107a of the interlayer insulating film 107 disposed on the upper portion has a cross section in the X direction of the pixel portion in FIG. 11A and a cross section in the Y1 direction of the pixel portion in FIG. As shown in FIG. 4, the X and Y1 directions have the same surface inclination angle in plan view. Accordingly, it is possible to obtain the solid-state imaging device 100 that obtains a stable lens effect, increases the light collection rate, and has high light receiving sensitivity at each light receiving unit.

Next, in Patent Document 2, a plasma CVD method is used, and in a plan view, a concave shape in which the cross-sectional structure sequentially decreases from above the transfer electrode to the upper side of the light receiving unit (or from the top of the light receiving unit to the upper side of the transfer electrode in order After forming a groove in the oxide film and forming a groove in the oxide film, a shielding film for light shielding is arranged in a region including the groove. A waveguide is formed for each light receiving portion by this shielding film, and the incident light is guided to the light receiving portion at the bottom of the concave portion, thereby improving the light collection efficiency for each light receiving portion.
JP 2006-140411 A JP-A-10-154805

  However, in the conventional solid-state imaging device 100 disclosed in Patent Document 1, the contact portions 106 must be formed uniformly for the number of pixels, the manufacturing process is complicated, and the contact resistance varies. Since a drive signal is transmitted from the shunt wiring 105 to the first-layer transfer electrode 103 via the contact portion 106 having high resistance, a variation in formation due to a formation deviation of the contact portion 106 occurs along with a voltage drop of the drive signal. This also causes variations in the light receiving sensitivity characteristics of the pixel portion.

  In the conventional solid-state imaging device disclosed in the above-mentioned Patent Document 2, a mountain-shaped oxide film that gradually increases from the light receiving portion toward the upper side of the transfer electrode is formed. Condensation efficiency decreases due to vignetting of incident light. Further, since the height direction of the laminated film on the substrate is increased as described above, it is difficult to reduce the light receiving portion, and the manufacturing process is complicated.

  The present invention solves the above-described conventional problems. By not forming a conventional contact portion, the manufacturing process can be simplified and a concave shape with good light collection efficiency can be formed without variation in shape. It is an object of the present invention to provide a solid-state imaging device and a manufacturing method thereof, and an electronic information device such as a camera-equipped mobile phone device using the solid-state imaging device as an image input device in an imaging unit.

  In the solid-state imaging device of the present invention, a plurality of light receiving units that photoelectrically convert image light from a subject are two-dimensionally provided on a semiconductor substrate or a semiconductor layer, and a plurality of light receiving units in the column direction among the plurality of light receiving units are provided. In a solid-state imaging device in which a vertical charge transfer path is provided on at least one side of the light receiving section, and a transfer electrode for applying a driving pulse is provided on the vertical charge transfer path, an end portion is an insulating film as the transfer electrode The first-layer transfer electrodes and the second-layer transfer electrodes are alternately arranged so as to overlap with each other, and the second-layer transfer electrodes are not overlapped with the first-layer transfer electrodes. A dummy film is disposed on the transfer electrode of the eye, thereby achieving the above object.

  Preferably, in the solid-state imaging device of the present invention, the first-layer transfer electrodes are formed in a plurality of T-shapes connected in the row direction, and the second-layer transfer electrodes are connected in the row direction. The first transfer electrode and the second transfer electrode overlap each other in the row direction, and end portions of the first transfer electrode projecting between the rows are formed between the rows. The end portion of the transfer electrode of the second layer that protrudes to overlap.

  Further preferably, the dummy film in the solid-state imaging device of the present invention is configured to be smaller than the width in the row direction of the second-layer transfer electrode.

  Further preferably, the dummy film in the solid-state imaging device of the present invention is formed of an oxide film, a nitride film or a polysilicon film.

  More preferably, the height of the dummy film in the solid-state imaging device of the present invention is the same as the height of the portion where the first-layer transfer electrode and the second-layer transfer electrode overlap. Is formed.

  More preferably, an oxide film is formed on the entire surface including the dummy film in the solid-state imaging device of the present invention, and the cross-sectional structure is uniform in the X direction around the light receiving portion and the Y direction perpendicular thereto. It is formed in a concave shape having an inclined surface of the oxide film.

  In the method for manufacturing a solid-state imaging device according to the present invention, a plurality of light receiving portions that photoelectrically convert image light from a subject are formed two-dimensionally on a semiconductor substrate or semiconductor layer, and the column direction of the plurality of light receiving portions In the method of manufacturing a solid-state imaging device in which a vertical charge transfer path is formed on at least one side of the plurality of light receiving sections, and a transfer electrode for applying a drive pulse is formed on the vertical charge transfer path, the vertical charge transfer section A first-layer transfer electrode forming step of forming a plurality of T-shaped first-layer transfer electrodes connected in the row direction via an insulating film on the path; and the first-layer transfer electrode and the row direction A plurality of inverted T-shaped second layers connected in the row direction so that the end portions of the first-layer transfer electrodes protruding between the rows overlap the end portions of the second-layer transfer electrodes. A second-layer transfer electrode forming step for forming a transfer electrode; and A dummy film forming step of forming a dummy film on the transfer electrode of the second layer that does not overlap with the transfer electrode of the layer, and forming an oxide film on the entire surface including the dummy film, A concave shape forming step in which the cross-sectional structure is formed into a concave shape having a uniform oxide film surface inclination with respect to the X direction in plan view and the Y direction orthogonal thereto, thereby achieving the above object. The

  In the method for manufacturing a solid-state imaging device according to the present invention, a plurality of light receiving portions that photoelectrically convert image light from a subject are formed two-dimensionally on a semiconductor substrate or semiconductor layer, and the column direction of the plurality of light receiving portions In the method of manufacturing a solid-state imaging device in which a vertical charge transfer path is formed on at least one side of the plurality of light receiving sections, and a transfer electrode for applying a drive pulse is formed on the vertical charge transfer path, the vertical charge transfer section A first-layer transfer electrode forming step of forming a plurality of T-shaped first-layer transfer electrodes connected in the row direction via an insulating film on the path; A second layer transfer electrode material / dummy film material film forming step in which a layer transfer electrode material is formed and a dummy film material is formed thereon, and a second layer transfer electrode is connected to the first layer transfer electrode. Dummy that forms a dummy film on the second-layer transfer electrode that does not overlap The film forming step overlaps with the first-layer transfer electrode along the row direction so that the end of the first-layer transfer electrode protruding between the rows overlaps with the end of the second-layer transfer electrode. A second-layer transfer electrode forming step of forming a plurality of inverted T-shaped transfer electrodes connected in the row direction, and forming an oxide film on the entire surface including the dummy film, And a concave shape forming step in which the cross-sectional structure is formed into a concave shape having a uniform oxide film surface inclination with respect to the X direction around the plane and the Y direction perpendicular thereto. Is achieved.

  Preferably, as a pre-process of the first-layer transfer electrode forming step in the method for manufacturing a solid-state imaging device according to the present invention, other conductivity type impurities are ion-implanted into the one conductivity type semiconductor substrate or the one conductivity type semiconductor layer to perform other conductivity. A first ion implantation step for forming a semiconductor region, and a second ion for ion-implanting one conductivity type impurity into the other conductivity type semiconductor region to form the light receiving portion and the vertical charge transfer portion adjacent thereto. Injection step.

  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 present invention, the first-layer transfer electrodes and the second-layer transfer electrodes are alternately arranged so that the end portions overlap with each other via the insulating film, and the second-layer transfer electrodes are connected to the first-layer transfer electrodes. A dummy film is disposed on the transfer electrode of the second layer that does not overlap. Thus, by providing the dummy film, it is possible to obtain a uniform lens effect with the same height on the substrate around the light receiving portion. Since the first-layer transfer electrode and the second-layer transfer electrode overlap, it is easy to create the transfer electrode, and it is possible to suppress charge transfer deterioration.

  Further, the first-layer transfer electrode is formed in a T-shape connected in the row direction, and the second-layer transfer electrode is formed in an inverted T-shape connected in the row direction. The transfer electrodes of the layers overlap in the row direction, and the end portions of the first-layer transfer electrodes protruding between the rows overlap the end portions of the second-layer transfer electrodes protruding between the rows. As a result, it is only necessary to supply drive pulses to the first-layer transfer electrode and the second-layer transfer electrode, respectively, and the island-shaped first-layer transfer electrode is driven from the shunt wiring via the contact portion as in the conventional case. There is no need to supply a pulse, and a conventional contact portion can be dispensed with. Therefore, there is no variation in formation due to a shift in the formation of the contact portion for each pixel portion, and there is no variation in the light receiving sensitivity characteristics of the pixel portion. Therefore, it is possible to simplify the manufacturing process and form a concave shape with good light collection efficiency without variation in shape.

  As described above, according to the present invention, the first-layer transfer electrodes are formed in a plurality of T-shapes connected in the row direction, and the second-layer transfer electrodes are formed in a plurality of inverted T-shapes connected in the row direction. The first transfer electrode and the second transfer electrode overlap in the row direction, and the end of the first transfer electrode protruding between the rows and the second transfer electrode protruding between the rows It is arranged to overlap the end. A columnar island-shaped dummy film is formed in a region (narrow width) smaller than the second-layer transfer electrode on the second-layer transfer electrode where the second-layer transfer electrode does not overlap the first-layer transfer electrode. Has been placed. For this reason, by not forming a conventional contact portion, the manufacturing process can be simplified and a concave shape with good light collection efficiency can be formed without variation in shape. Further, in the solid-state imaging device having the structure according to the manufacturing method of the present invention, the melt angle of the oxide film on the transfer electrode becomes the same surface inclination in the X direction and the Y direction, so that the light collection efficiency is high and the light receiving sensitivity is high. Become.

  Embodiment 1 of a solid-state imaging device and manufacturing method thereof according to the present invention, Embodiment 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 2 will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a plan view showing an essential part of an imaging region of the solid-state imaging device and an electrode pattern thereof in Embodiment 1 of the present invention. 2A is a longitudinal sectional view in the X direction of FIG. 1, FIG. 2B is a longitudinal sectional view in the Y1 direction of FIG. 1, and FIG. 2C is a longitudinal sectional view in the Y2 direction of FIG.

  1 and FIGS. 2A to 2C, the solid-state imaging device 1 of Embodiment 1 includes a plurality of light receiving units (openings) that photoelectrically convert image light from a subject on a semiconductor substrate or semiconductor layer. 2) is provided in a two-dimensional manner, and a vertical CCD 3 as a vertical charge transfer path 3 is provided on one side (left side) of a plurality of light receiving sections (openings 2), and the vertical CCD 3 as the vertical charge transfer path 3 is provided. The first-layer transfer electrodes 4 and the second-layer transfer electrodes 5 for applying the drive pulse are alternately and repeatedly disposed thereon. In this case, the first-layer transfer electrodes 4 are formed in a plurality of T-shapes connected in the row direction, and the second-layer transfer electrodes 5 are formed in a plurality of inverted T-shapes connected in the row direction. The first-layer transfer electrode 4 and the second-layer transfer electrode 5 overlap each other in the row direction, and the end of the first-layer transfer electrode 4 protruding between the rows and the second-layer transfer electrode protruding between the rows 5 is overlapped with the end portion. The end portion of the second-layer transfer electrode 5 overlaps the end portion of the first-layer transfer electrode 4 via the insulating film.

  On the second transfer electrode 5 where the second transfer electrode 5 does not overlap the first transfer electrode 4, a columnar and island-like region is formed in a smaller area (narrow width) than the second transfer electrode 5. A dummy structure 6 (dummy film) is disposed.

  The dummy structure portion 6 (dummy film) is formed of an oxide film, a nitride film, a polysilicon film, or the like, and is formed as a convex portion for aligning the height around the light receiving portion (opening portion 2). After the formation of the dummy structure portion 6, an oxide film serving as an interlayer insulating film and a patterned shielding film (light shielding film) are disposed on the entire surface of the substrate using a general method. Further, the interlayer insulating film 7 is disposed thereon and melt processing is performed, so that in the cross-sectional structure of each pixel portion, a concave portion 7a having the same surface angle in the X direction and the Y1 direction in plan view is formed. In the solid-state imaging device 1 according to the first embodiment, the melt angle and the height of the surface of the interlayer oxide film 7 on the transfer electrode 5 are equal in the X direction and the Y1 direction in plan view, and the light collection efficiency is high, and the light is received. A highly sensitive solid-state imaging device 1 can be obtained.

  Further, in the solid-state imaging device 1 according to the first embodiment, since the conventional contact portion is not formed, it is not necessary to form the contact portion evenly for the number of pixels. Therefore, the concave portion 7a having high light collection efficiency can be formed, and the variation in the light receiving sensitivity characteristic of the pixel portion due to the variation in the formation of the contact portion (displacement of the contact portion) does not occur.

  Hereinafter, a method for manufacturing the solid-state imaging device 1 according to the first embodiment in which a contact portion is not formed as in the related art will be described.

  3 to 8 are main part longitudinal cross-sectional views for explaining each step in the method of manufacturing the solid-state imaging device 1 of FIG. 1, wherein (a) is a vertical cross-sectional view in the X direction of FIG. ) Is a longitudinal sectional view in the Y1 direction of FIG. 1, and (c) is a longitudinal sectional view in the Y2 direction of FIG.

  First, as shown in the ion implantation steps of FIGS. 3A to 3C, thermal oxidation as a sacrificial oxide film for preventing surface roughness due to ion implantation on a silicon substrate 10 which is an N-type semiconductor substrate. The film 11 is formed to a thickness of about 100 angstroms to 1000 angstroms, and ion implantation of P-type impurities (generally, boron is used as the ion species) is formed thereon to form the P well portion 12.

  Thereafter, ion implantation of N-type impurities (generally, phosphorus is used as the ion species) is performed, and the vertical CCD 3 of the N-type diffusion layer as a vertical charge transfer path and a light receiving portion of the N-type diffusion layer beside it. 14 are formed alternately. In this case, arsenic ions are implanted into the surface portions of the vertical CCD 3 and the light receiving unit 14.

  Next, as shown in the first-layer transfer electrode forming step in FIGS. 4A to 4C, after the thermal oxide film 11 is peeled off, a gate made of an ONO film including a SiN film is formed on the substrate. An insulating film 15 is formed. A material film for the first transfer electrode 4 is formed thereon. In this case, a polysilicon film is used as the material film of the first transfer electrode 4. The material film of the first transfer electrode 4 is patterned into a predetermined T-shape that is orthogonal to the vertical charge transfer path in the column direction and connected in the row direction to form the first transfer electrode 4. In contrast, a thermal oxidation process is performed.

Subsequently, as shown in the polysilicon film / oxide film forming process of FIGS. 5A to 5C, a silicon nitride film (SiN film) and an oxide film to be the gate insulating film 17 are formed on the substrate. Deploy. After that, a polysilicon film 5a which is a material film to be the second transfer electrode 5 is disposed. As the polysilicon film 5a, one containing N-type impurities 1E20 to 1E21 (atms / cm ⁻³ ) is used. The N-type impurity is generally phosphorus (P), but a gas addition method during polysilicon deposition or a method using ion implantation and thermal diffusion after the polysilicon film 5a is disposed may be used.

  Further, an oxide film or nitride film 6a (silicon oxide film or silicon nitride film) to be the dummy structure portion 6 (dummy film) is disposed on the polysilicon film 5a. The thickness of the oxide film or nitride film 6a is such that the height of the oxide film or nitride film 6a above the portion of the second transfer electrode 5 formed as a single layer is the same as that of the first transfer electrode 4 and the second layer. The film thickness is adjusted to be equal to the height of the upper surface of the second-layer transfer electrode 5 at the portion where the transfer electrode 5 of the eye overlaps. Further, in order to form the transfer electrode 5 of the second layer, the photoresist film is patterned on the portion formed by the single layer, and the photoresist mask 16 is left.

  Further, as shown in the dummy structure forming step in FIGS. 6A to 6C, the oxide film or nitride film is removed by dry etching using the photoresist mask 16 patterned in a predetermined shape as a mask. Thus, the oxide film or nitride film 6a under the photoresist mask 16 is left as the island-like dummy structure portion 6 (dummy film). As the etching method at this time, a wet method may be used.

  Thereafter, as shown in the second-layer transfer electrode forming step in FIGS. 7A to 7C, a photoresist film is formed on the polysilicon film 5a, and the photoresist film is formed in a predetermined pattern. A second-layer transfer electrode 5 is formed. The oxide film or nitride film 6 a of the dummy structure portion 6 is formed to be smaller than the width of the second-layer transfer electrode 5.

  Further, as shown in the oxide film concave shape forming step in FIGS. 8A to 8C, an insulating film (not shown) is disposed on the entire surface of the substrate including the dummy structure portion 6, and thereafter, above the vertical CCD 3. A light-shielding film (light-shielding film) (not shown) for light shielding is formed, and the oxide film 7 is formed on the light-shielding film opened on the light-receiving part 14 and is subjected to a reflow process. A concave shape 7a having a uniform surface inclination in the X direction and the Y1 direction can be formed.

  Here, in particular, although the insulating film and the shielding film are not illustrated, the insulating film and the shielding film may be provided around the light receiving unit 14 so that the periphery of the light receiving unit 14 has the same height. The oxide film 7 that performs this reflow treatment can improve the reflow characteristics by using an oxide film to which boron and phosphorus are added.

  Thereafter, although not shown, an inner lens as shown by a dotted line in FIGS. 2 (a) and 2 (b) is formed on the oxide film 7, or a transparent film having a high refractive index is formed instead. To give a lens effect. Furthermore, if necessary, after forming a planarizing film thereon, a color filter and an on-chip microlens can be formed thereon.

  As described above, according to the first embodiment, the first-layer transfer electrode 4 is formed in a T-shape connected in the row direction, and the second-layer transfer electrode 5 is formed in an inverted T-shape connected in the row direction. The first transfer electrode 4 and the second transfer electrode 5 are overlapped in the row direction, and the end of the first transfer electrode 4 protruding between the rows and the second layer protruding between the rows The end of the transfer electrode 5 is arranged so as to overlap. For this reason, it is not necessary to form a contact portion as in Patent Document 1, and therefore, there is no variation in contact resistance, the manufacturing process is simplified, and the substrate height is lower than that in Patent Document 2, It is possible to form a concave shape with good light collection efficiency without variation in shape. In this case, the second-layer transfer electrode 5 is columnar in a region (narrow width) smaller than the second-layer transfer electrode 5 on the second-layer transfer electrode 5 that does not overlap the first-layer transfer electrode 4. Since the island-like dummy structure portion 6 (dummy film) is disposed, the melt angle of the interlayer oxide film on the transfer electrode 5 is equal in the X direction and the Y1 direction in the concave portion 7a. The solid-state imaging device 1 having high light efficiency and high light receiving sensitivity can be obtained.

  In addition to the case of the first embodiment, a polysilicon film is disposed, a second transfer electrode 5 is formed from the polysilicon film, an insulating film is disposed thereon, and then a polysilicon film is formed on the insulating film. A silicon film may be disposed, and the dummy structure 6 having a predetermined shape may be formed using the polysilicon film on the insulating film.

  In the solid-state imaging device 1 according to the first embodiment, the plurality of light receiving units are arranged in a matrix in the matrix direction to form the imaging unit. However, the present invention is not limited to this, and the plurality of light receiving units are arranged for each line. You may arrange in a staggered pattern. Although the vertical charge transfer direction is configured to transfer charges in the same direction, they may be in opposite directions.

  In the method of manufacturing the solid-state imaging device 1 according to the first embodiment, the T-shaped first transfer electrode 4 connected in the row direction via the insulating film on the vertical CCD 3 serving as the vertical charge transfer path. A polysilicon film 5a as a second-layer transfer electrode material is formed on the entire surface including the first-layer transfer electrode forming step and the first-layer transfer electrode 4, and an oxide film as a dummy film material is formed thereon. Alternatively, the second-layer transfer electrode material / dummy film material film-forming step for forming the nitride film 6a and the second-layer transfer electrode 5 on the portion where the second-layer transfer electrode 5 does not overlap the first-layer transfer electrode 4 A dummy film forming step of forming a dummy film 6 on the first layer, and an end portion of the first-layer transfer electrode 4 projecting between the rows and the second-layer transfer electrode, overlapping with the first-layer transfer electrode 4 in the row direction. Forming a second-layer transfer electrode 5 of an inverted T-shape connected in the row direction so that the end of 5 is overlapped 2 The oxide transfer film 7 is formed on the entire surface including the dummy transfer electrode 6 and the dummy transfer film 6, and the cross-sectional structure of the light receiving portion 14 has a uniform surface inclination in the X direction in plan view and in the Y direction perpendicular thereto. However, the present invention is not limited to this, and as a manufacturing method of the solid-state imaging device 1 of another example of the first embodiment, a vertical charge transfer path is a vertical charge transfer path. A first-layer transfer electrode forming step for forming a T-shaped first-layer transfer electrode 4 connected in the row direction via an insulating film on the CCD 3, and the first-layer transfer electrode 4 along the row direction An inverted T-shaped second-layer transfer electrode connected in the row direction so that the end of the first-layer transfer electrode 4 protruding between the rows overlaps with the end of the second-layer transfer electrode 5. 5 and the second-layer transfer electrode forming step, and the second-layer transfer electrode 5 is the first-layer transfer electrode 4. A dummy film forming step for forming the dummy film 6 on the second-layer transfer electrode 5 in the non-overlapping portion, and an oxide film 7 is formed on the entire surface including the dummy film 6 so that the light receiving unit 14 is viewed in plan X And a concave shape forming step in which the cross-sectional structure is formed into a concave shape 7a having a uniform surface inclination in the Y direction perpendicular to the direction.

  Further, in the method for manufacturing the solid-state imaging device 1 according to the first embodiment, as a pre-process of the first-layer transfer electrode forming process, P-type impurities are ion-implanted into the N-type semiconductor substrate 10 or the N-type semiconductor layer to form a P-type semiconductor. The first ion implantation step for forming the P well 12 as the region and the N type and P type may be reversed. In short, other conductivity type impurities are ion implanted into the one conductivity type semiconductor substrate or one conductivity type semiconductor layer. Then, a first ion implantation step for forming the other conductivity type semiconductor region, and one conductivity type impurity is ion implanted into the other conductivity type semiconductor region, and the vertical CCD 3 as a vertical charge transfer path adjacent to the light receiving portion 14. And a second ion implantation step for forming the structure.

(Embodiment 2)
FIG. 9 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. 9, the electronic information device 90 of 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 of 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 95. 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, based on the color image signal from the solid-state imaging device 91, it can be displayed on the display screen, or can be printed out on the paper by the image output device 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.

  In the first embodiment, the first-layer transfer electrodes 4 and the second-layer transfer electrodes 5 are alternately arranged so that the end portions overlap with each other via an insulating film, and the second-layer transfer electrode 5 is 1 Since the dummy film 6 is disposed on the second-layer transfer electrode 5 in the central portion that does not overlap with the transfer electrode 4 in the layer, it is not necessary to form a contact portion as in the prior art, and the manufacturing process is reduced. While simplifying, the objective of this invention which can form a recessed part shape with sufficient condensing efficiency without shape variation can be achieved.

  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 the 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 composed of a semiconductor element that photoelectrically converts image light from a subject and captures the image, and uses this solid-state imaging device as an image input device in an imaging unit, such as a digital video camera and a digital still camera In the field of electronic information equipment such as digital camera, image input camera such as surveillance camera, scanner device, facsimile device, television phone device, mobile phone device with camera, etc. The manufacturing process is simplified, and a concave shape with good light collection efficiency can be formed without variation in shape.

It is a top view which shows the principal part of the imaging region of the solid-state image sensor in Embodiment 1 of this invention, and its electrode pattern. 1A is a longitudinal sectional view in the X direction in FIG. 1, FIG. 1B is a longitudinal sectional view in the Y1 direction in FIG. 1, and FIG. 2C is a longitudinal sectional view in the Y2 direction in FIG. FIG. 2 is a longitudinal sectional view of an essential part for explaining an ion implantation step in the method for manufacturing the solid-state imaging device 1 in FIG. 1, wherein (a) is a longitudinal sectional view in the X direction of FIG. 1, and (b) is a sectional view of FIG. Y1 direction longitudinal cross-sectional view, (c) is a Y2 direction vertical cross-sectional view of FIG. FIG. 2 is a longitudinal sectional view of a main part for explaining a first-layer transfer electrode forming step in the method for manufacturing the solid-state imaging device 1 of FIG. 1, wherein (a) is a longitudinal sectional view in the X direction of FIG. 1 is a longitudinal sectional view in the Y1 direction of FIG. 1, and FIG. 1C is a longitudinal sectional view in the Y2 direction of FIG. FIG. 2 is a longitudinal sectional view of a main part for explaining a polysilicon film / oxide film forming step in the method of manufacturing the solid-state imaging device 1 of FIG. 1, wherein (a) is a longitudinal sectional view in the X direction of FIG. ) Is a longitudinal sectional view in the Y1 direction of FIG. 1, and (c) is a longitudinal sectional view in the Y2 direction of FIG. 2A and 2B are main part longitudinal cross-sectional views for explaining a dummy structure part forming step in the method for manufacturing the solid-state imaging device 1 in FIG. 1, wherein FIG. 1A is a vertical cross-sectional view in the X direction of FIG. 1, and FIG. 1 is a longitudinal sectional view in the Y1 direction, and FIG. 1C is a longitudinal sectional view in the Y2 direction in FIG. FIG. 2 is a longitudinal sectional view of a main part for explaining a second-layer transfer electrode forming step in the method for manufacturing the solid-state imaging device 1 in FIG. 1, wherein (a) is a longitudinal sectional view in the X direction of FIG. 1 is a longitudinal sectional view in the Y1 direction of FIG. 1, and FIG. 1C is a longitudinal sectional view in the Y2 direction of FIG. It is a principal part longitudinal cross-sectional view for demonstrating the oxide film recessed shape formation process in the manufacturing method of the solid-state image sensor 1 of FIG. 1, Comprising: (a) is a X direction longitudinal cross-sectional view of FIG. 1 is a longitudinal sectional view in the Y1 direction of FIG. 1, and (c) is a longitudinal sectional view in the Y2 direction of FIG. As Embodiment 2 of this invention, it is a block diagram which shows the schematic structural example of the electronic information device which used the solid-state imaging device containing the solid-state image sensor of Embodiment 1 of this invention for the imaging part. It is a top view which shows the principal part of the imaging region of the conventional solid-state image sensor currently disclosed by patent document 1, and its electrode pattern. 10A is a sectional view in the X direction of FIG. 10, FIG. 10B is a sectional view in the Y1 direction of FIG. 10, and FIG. 10C is a sectional view in the Y2 direction of FIG.

Explanation of symbols

1 Solid-state image sensor 2 Aperture 3 Vertical CCD
4 First-layer transfer electrode 5 Second-layer transfer electrode 5a Polysilicon film 6 Dummy structure (dummy film)
6a Oxide film or nitride film 7 Interlayer oxide film 7a Concave shaped part 10 Silicon substrate 11 Thermal oxide film 12 P well part 14 Light receiving part 15 First gate insulating film 16 Photoresist mask 17 Second gate insulating film 90 Electronic information equipment 91 Solid Imaging device 92 Memory unit 93 Display means 94 Communication means 95 Image output means

Claims (10)

A plurality of light receiving portions that photoelectrically convert image light from a subject are provided on a semiconductor substrate or semiconductor layer in a two-dimensional shape, and are perpendicular to at least one side of the plurality of light receiving portions in the column direction among the plurality of light receiving portions. In a solid-state imaging device in which a charge transfer path is provided and a transfer electrode for applying a drive pulse on the vertical charge transfer path is provided.
As the transfer electrode, the first-layer transfer electrode and the second-layer transfer electrode are alternately arranged so that the end portions overlap with each other via an insulating film, and the second-layer transfer electrode is transferred to the first-layer transfer electrode. A solid-state imaging device in which a dummy film is disposed on the second-layer transfer electrode in a portion not overlapping with the electrode.   The first-layer transfer electrodes are formed in a plurality of T-shapes connected in the row direction, and the second-layer transfer electrodes are formed in a plurality of inverted T-shapes connected in the row direction. The transfer electrode of the second layer and the transfer electrode of the second layer overlap in the row direction, the end of the transfer electrode of the first layer protruding between the rows, and the end of the transfer electrode of the second layer protruding between the rows The solid-state imaging device according to claim 1, wherein   The solid-state imaging device according to claim 1, wherein the dummy film is configured to be smaller than a width in the row direction of the second-layer transfer electrode.   The solid-state imaging device according to claim 1, wherein the dummy film is made of an oxide film, a nitride film, or a polysilicon film.   2. The solid according to claim 1, wherein the dummy film is formed to have a thickness that is the same as a height of a portion where the first-layer transfer electrode and the second-layer transfer electrode overlap each other. Image sensor.   An oxide film is formed on the entire surface including the dummy film, and the cross-sectional structure is formed in a concave shape having an even oxide film surface inclination with respect to the X direction around the light receiving portion and the Y direction perpendicular thereto. The solid-state imaging device according to claim 1. A plurality of light receiving portions that photoelectrically convert image light from a subject are two-dimensionally formed on a semiconductor substrate or semiconductor layer, and perpendicular to at least one side of the plurality of light receiving portions in the column direction among the plurality of light receiving portions. In a method of manufacturing a solid-state imaging device in which a charge transfer path is formed and a transfer electrode for applying a drive pulse is formed on the vertical charge transfer path.
A first-layer transfer electrode forming step of forming a plurality of T-shaped first-layer transfer electrodes connected in the row direction via an insulating film on the vertical charge transfer portion path;
Connected in the row direction so that the end of the first-layer transfer electrode and the end of the second-layer transfer electrode overlap with the first-layer transfer electrode along the row direction. A second-layer transfer electrode forming step of forming the plurality of inverted T-shaped transfer electrodes of the second layer,
A dummy film forming step of forming a dummy film on the second-layer transfer electrode in a portion where the second-layer transfer electrode does not overlap the first-layer transfer electrode;
An oxide film is formed on the entire surface including the dummy film, and the cross-sectional structure is formed in a concave shape having an even oxide film surface inclination with respect to the X direction around the light receiving portion and the Y direction perpendicular thereto. The manufacturing method of the solid-state image sensor which has a concave shape formation process to do. A plurality of light receiving portions that photoelectrically convert image light from a subject are two-dimensionally formed on a semiconductor substrate or semiconductor layer, and perpendicular to at least one side of the plurality of light receiving portions in the column direction among the plurality of light receiving portions. In a method of manufacturing a solid-state imaging device in which a charge transfer path is formed and a transfer electrode for applying a drive pulse is formed on the vertical charge transfer path.
A first-layer transfer electrode forming step of forming a plurality of T-shaped first-layer transfer electrodes connected in the row direction via an insulating film on the vertical charge transfer portion path;
A second layer transfer electrode material / dummy film material film forming step of forming a second layer transfer electrode material on the entire surface including the first layer transfer electrode and forming a dummy film material thereon;
A dummy film forming step of forming a dummy film on the second transfer electrode in a portion where the second transfer electrode does not overlap with the first transfer electrode;
The first transfer electrode overlaps in the row direction, and the end of the first transfer electrode protruding between the rows overlaps the end of the second transfer electrode in the row direction. A second layer transfer electrode forming step of forming a plurality of connected inverted T-shaped second layer transfer electrodes;
An oxide film is formed on the entire surface including the dummy film, and the cross-sectional structure is formed in a concave shape having an even oxide film surface inclination with respect to the X direction around the light receiving portion and the Y direction perpendicular thereto. The manufacturing method of the solid-state image sensor which has a concave shape formation process. As a pre-process of the first layer transfer electrode forming process,
A first ion implantation step of ion-implanting other conductivity type impurities into one conductivity type semiconductor substrate or one conductivity type semiconductor layer to form another conductivity type semiconductor region;
9. The method according to claim 7, further comprising: a second ion implantation step of ion-implanting one conductivity type impurity into the other conductivity type semiconductor region to form the light receiving unit and the vertical charge transfer unit path adjacent thereto. Manufacturing method of solid-state image sensor.   An electronic information device using the solid-state imaging device according to claim 1 as an image input device in an imaging unit.

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