JP2009194145A - Solid-state image sensing element and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state imaging element generating no color mixing, even for small removing region of an diffusion-preventing film with an increase in the diffraction scattering of an incident light and having superior color reproducibility, and to provide a manufacturing method for the solid-state imaging element. <P>SOLUTION: In the solid-state imaging element, wiring layers 113 laminating interlayer insulating films 110, copper wirings 111 and the diffusion-preventing films 112 preventing the diffusion of copper are formed on the main surface of a semiconductor substrate 100 forming a light-receiving section 101 conducting a photoelectric conversion on the main surface in a single-layer or a multilayer structure, and hole sections 122 formed by removing a region corresponding to the light-receiving section of the wiring layers 113 are filled with light-guide members 123. In the solid-state imaging element, light-transmission preventing films 124 are formed among the internal peripheral surfaces of the hole sections 122 and the light guide members 123. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device such as a CCD (Charge Coupled Device) image sensor and a CMOS (Complementary Metal Oxide Semiconductor) image sensor and a manufacturing method thereof, and more particularly to a solid-state imaging device employing copper wiring for wiring and a manufacturing method thereof.

  In recent years, in this type of solid-state imaging device, the number of pixels has been increased and the size of pixels has been reduced, and accordingly, the wiring adopted is changed from aluminum (Al) wiring to copper (Cu) wiring.

  By the way, since copper has a large diffusion coefficient in the oxide film, it is necessary to prevent copper diffusion when copper wiring is employed. Therefore, in general, a barrier metal made of tantalum (Ta) or tantalum nitride (TaN) is formed on the lower and lateral sides of the copper wiring, and diffusion prevention made of a silicon nitride film or a silicon carbide film is formed on the upper side of the copper wiring. A film is formed. Therefore, in an ordinary SLSI (System Large Scale Integrated Circuit) manufactured using a known wiring forming technique, a plurality of interlayer insulating films and diffusion preventing films having different refractive indexes are stacked above the light receiving portion.

  FIG. 12 is a cross-sectional view schematically showing the structure around the light receiving portion of a conventional solid-state imaging device. For example, in the solid-state imaging device illustrated in FIG. 12, a plurality of light receiving units 501 and detection units 504 that perform photoelectric conversion are formed in an upper layer of the silicon substrate 500, for example, in a two-dimensional array. A gate interlayer insulating film 502, a gate electrode 503, and a premetal interlayer insulating film 505 are formed. Further thereon, a first interlayer insulating film 506, a first copper wiring 507 and a first diffusion preventing film 508, a second interlayer insulating film 509, a second copper wiring 510 and a second diffusion preventing film 511, and a third An interlayer insulating film 512, a third copper wiring 513, and a third diffusion prevention film 514 are laminated, and further thereon, an interlayer insulating film 515, a protective film 516, a color filter 517, and a microlens 518 are formed.

In such a solid-state imaging device, the interlayer insulating films 505, 506, 509, 512, and 515 are made of, for example, a silicon oxide film (SiO ₂ ), and the diffusion prevention films 508, 511, and 514 are made of, for example, a silicon carbide film (SiC). Thus, it has a multilayer structure with films having different refractive indexes. For this reason, incident light may be reflected at the interface of each film, or may be affected by multiple interference, resulting in a decrease in light collection efficiency to the light receiving unit 501 and a decrease in sensitivity characteristics of the solid-state imaging device. .

Therefore, in the solid-state imaging device according to Patent Documents 1 and 2, the region of the diffusion prevention films 508, 511, and 514 above the light receiving portion 501 is removed and a light guide member 519 is provided there, and the number of layers above the light receiving portion 501 is set. This reduces the sensitivity characteristic of the solid-state image sensor.
JP 2003-324189 A JP-A-2005-311015

  By the way, in order to increase the number of pixels and the cost of the solid-state imaging device, it is essential to reduce the cell size of the pixel portion. For this purpose, the area of the light receiving portion 501 must be reduced, As a result, the area of the region from which the diffusion prevention films 508, 511, and 514 are removed is also reduced. When the area of the removal region becomes smaller and the incident width becomes shorter than the wavelength of light, the light incident on the light guide member 519 causes diffraction scattering as shown by the solid line arrow in FIG. It becomes easy to leak from the side of the light guide member 519. Since the leaked light is reflected and propagated between the diffusion prevention films 508 and 511, for example, as indicated by the broken-line arrows in FIG. 12, it enters adjacent pixels and causes color mixing (crosstalk).

  For example, in a cell having a pixel size of 2.8 um × 2.8 um, if the 0.13 um wiring pattern technology is used, the removal regions of the diffusion prevention films 508, 511, and 514 can be secured with a size of 1.0 um × 1.0 um or more. Therefore, an incident width sufficiently wider than the transmission wavelength of visible light (380 to 780 nm) can be obtained, and no diffraction scattering of incident light occurs.

  However, in a cell having a pixel size of 1.7 μm × 1.7 μm, if the 0.13 μm wiring pattern technology is used, the removal regions of the diffusion prevention films 508, 511, and 514 become as small as 0.6 μm × 0.6 μm, and visible light is transmitted. Since the incident width is narrower than the wavelength (particularly on the long wavelength side), diffraction scattering of incident light occurs, resulting in color mixing.

  In view of the above problems, the present invention provides a solid-state imaging device having good color reproducibility without color mixing even when the removal region of the anti-diffusion film is so small that incident light is diffracted and scattered, and a method for manufacturing the same. For the purpose.

  In order to achieve the above object, the solid-state imaging device according to the present invention prevents diffusion of an interlayer insulating film, copper wiring, and copper above the main surface of the semiconductor substrate on which a light receiving portion that performs photoelectric conversion is formed on the main surface. A solid-state imaging device in which a wiring layer in which a diffusion prevention film is laminated is formed in a single layer or a multilayer structure, and a light guide member is filled in a hole provided by removing a region corresponding to a light receiving portion of the wiring layer; A light transmission preventing film is formed between the inner peripheral surface of the hole and the light guide member.

The method for manufacturing a solid-state imaging device according to the present invention includes a step of forming a light receiving portion that performs photoelectric conversion on a main surface of a semiconductor substrate, and an interlayer insulating film, a copper wiring, and copper diffusion above the main surface of the semiconductor substrate. A step of forming a wiring layer in which a diffusion preventing film to prevent is laminated in a single layer or a multilayer structure, a step of removing a region corresponding to a light receiving portion of the wiring layer and providing a hole,
The method includes a step of forming a light transmission preventing film on an inner peripheral surface of the hole portion, and a step of filling the hole portion with a light guide member.

  In the solid-state imaging device according to the present invention, since the light transmission preventing film is formed between the inner peripheral surface of the hole and the light guide member, the light incident on the light guide member is difficult to leak into the wiring layer. Therefore, the leaked light is difficult to propagate through the wiring layer and enter the adjacent pixels. As a result, color mixing is unlikely to occur, and color reproducibility is good.

  The method for manufacturing a solid-state imaging device according to the present invention includes a step of removing a region corresponding to the light receiving portion of the wiring layer and providing a hole, and a step of forming a light transmission preventing film on the inner peripheral surface of the hole. Thus, it is possible to manufacture a solid-state imaging device with good color reproducibility.

  Hereinafter, a solid-state imaging device and a manufacturing method thereof according to embodiments of the present invention will be described with reference to the drawings. Note that each of the solid-state imaging devices according to the first, second, and third embodiments has a pixel region in which photoelectric conversion cells each including a photodiode that performs photoelectric conversion and a plurality of transistors are arranged in a two-dimensional array. is doing.

[First Embodiment]
<Configuration of solid-state image sensor>
FIG. 1 is a cross-sectional view schematically showing a structure around a light receiving portion of a solid-state imaging device according to the first embodiment of the present invention. As shown in FIG. 1, the solid-state imaging device according to the first embodiment includes a silicon substrate 100 as a semiconductor substrate. On the upper layer of the silicon substrate 100, a light receiving portion (photodiode) 101 that performs photoelectric conversion and a detection portion (channel region) 102 are formed as an N-type impurity region.

The impurity concentration of the light receiving unit 101 may be a concentration that allows photoelectric conversion, but is preferably adjusted to about 1.0E12 cm ^{−2 to} 1.0E13 cm ⁻² . The light receiving portion 101 is preferably formed over a depth of about 0.2 to 2.0 μm from the substrate surface.

The light receiving unit 101 employs a buried structure for suppressing dark current, and a surface P-type layer 103 is formed on the upper surface thereof with an energy of 3 to 10 KeV and a high concentration of 1.0E13 cm ^{−2 to} 1.0E14 cm ^−2. Has been.

The impurity concentration of the detection unit 102 may be a concentration that allows ohmic connection by metal wiring, but is preferably 1.0E15 cm ⁻² or more. Moreover, it is preferable that the detection part 102 is formed over the depth of about 0.1-0.5um from the substrate surface.

  On the upper surface (main surface) of the silicon substrate 100, a gate electrode 105 made of polysilicon is formed via a gate interlayer insulating film 104 made of a silicon oxide film.

  A side wall 106 made of a silicon oxide film (5 to 15 nm) and a silicon nitride film (50 to 70 nm) is formed on a part of the side surface of the gate electrode 105. Further, the gate electrode 105 is formed of a silicon oxide film (5 to 15 nm) and a silicon nitride film (50 to 70 nm) so as to cover the remaining part of the side surface and part of the upper surface and the upper surface of the surface P-type layer 103. An antireflection film 107 is formed. Note that the region of the antireflection film 107 that is above the light receiving portion 101 is made of a silicon oxide film with a reduced thickness.

  In addition to improving the sensitivity characteristics by the antireflection effect, the antireflection film 107 functions as an etching stopper when etching the upper part of the light receiving portion 101 to form a hole portion 122 to be described later. It plays a role of preventing plasma damage when a light transmission preventing film 124 described later is formed by etching.

  Above the silicon substrate 100, further, in order from the silicon substrate 100 side, a stopper film (liner film) 108, a premetal interlayer insulating film 109, a first interlayer insulating film 110, a first copper wiring 111, and a first diffusion prevention A first wiring layer 113 in which a film 112 is stacked, a second interlayer insulating film 114, a second wiring layer 117 in which a second copper wiring 115 and a second diffusion barrier film 116 are stacked, a third interlayer insulating film 118, a third layer The copper wiring 119 and the third wiring layer 121 on which the third diffusion prevention film 120 is laminated are formed in a multilayer structure.

  The stopper film 108 is a silicon nitride film formed in a region other than the region overlying the light receiving portion 101, and serves as an etching stopper for dry etching when the first connection hole (not shown) is formed in the premetal interlayer insulating film 109. Play a role. The premetal interlayer insulating film 109 is made of a BPSG film (Boron-Phospho-Silicate-Glass) and has a film thickness of 460 nm.

  Each interlayer insulating film 110, 114, 118 is made of a silicon oxide film. The thickness of the first interlayer insulating film 110 is 260 nm, and the thickness of the second interlayer insulating film 114 and the third interlayer insulating film 118 is 565 nm. The film thickness of the first copper wiring 111 is 260 nm, and the film thickness of the second copper wiring 115 and the third copper wiring 119 is 335 nm.

  Each diffusion prevention film 112, 116, 120 is made of a silicon nitride film and has a thickness of 170 nm, and plays a role of preventing the copper of each copper wiring 111, 115, 119 from diffusing. The diffusion preventing film is not limited to a silicon nitride film, and even if a silicon carbide film is used, it plays a role of preventing copper diffusion having a large diffusion coefficient in the oxide film.

  A hole 122 that penetrates the premetal interlayer insulating film 109 and the wiring layers 113, 117, and 121 above the light receiving portion 101 (light receiving portion equivalent region) in the thickness direction is formed. The light guide member 123 is filled therein, and a light transmission preventing film 124 is formed on the inner peripheral surface of the hole 122.

  The light guide member 123 is made of a silicon oxide film, is formed so as to penetrate the premetal interlayer insulating film 109 and the wiring layers 113, 117, and 121 in the thickness direction, and is integrated with an interlayer film 125 described later.

  The light transmission preventing film 124 is a silicon nitride film with a film thickness of 60 nm formed over the entire inner peripheral surface of the hole 122, and the first light transmission preventing part 124a, the second light transmission preventing part 124b, and the third light. The transmission preventing portion 124c is used. The first light transmission preventing portion 124 a is formed between the light guide member 123 and the premetal interlayer insulating film 109 and between the light guide member 123 and the first wiring layer 113. The second light transmission preventing portion 124 b is formed between the light guide member 123 and the second wiring layer 117. The third light transmission preventing portion 124 c is formed between the light guide member 123 and the third wiring layer 121.

  The first light transmission preventing portion 124 a is in contact with the first diffusion preventing film 112. The first light transmission preventing portion 124a is in contact with the antireflection film 107 and the stopper film 108, but may be configured to be in contact with the gate electrode 105 for the sake of layout. The second light transmission preventing portion 124 b is in contact with the second diffusion preventing film 116. The third light transmission preventing portion 124 c is in contact with the third diffusion preventing film 120.

  Since the light transmission preventing film 124 is formed, light that is diffracted and scattered and leaks from the side of the light guide member 123 to the premetal interlayer insulating film 109 and the wiring layers 113, 117, and 121 is indicated by a solid line arrow in FIG. 1. As shown, it is reflected by the light transmission preventing film 124 (the interface between the light transmission preventing film 124 and another member) and guided to the light receiving unit 101, or absorbed when the light is transmitted through the light transmission preventing film 124. The light intensity can be attenuated. Therefore, light leaks into the premetal interlayer insulating film 109 and each interlayer insulating film 110, 114, 118, and as shown by the broken arrows in FIG. 1, between the respective diffusion preventing films 112, 116, 120, and the first diffusion preventing film. The reflection between the film 112 and the stopper film 108 is difficult to propagate while repeating the reflection, and as a result, the color mixture due to the leaked light entering the adjacent pixels hardly occurs.

  In particular, in the first embodiment, since the light transmission preventing film 124 is formed over the entire inner peripheral surface of the hole 122, light is transmitted to the premetal interlayer insulating film 109 and the wiring layers 113, 117, 121. It is hard to leak.

  The light transmission preventing film 124 is preferably a film using an insulating material such as a silicon nitride film, a silicon carbide film, or an oxynitride film. In the case of a film using an insulating material, an etching residue (metal residue) is less likely to occur when the light transmission preventing film 124 is formed compared to a film using a metal material, and as a result, connection holes (vias) are formed. In addition, since a short circuit failure in wiring is unlikely to occur, a solid-state imaging device with good manufacturing yield characteristics can be obtained.

  Further, the light transmission preventing film 124 is not limited to the case where it is constituted by one kind of film, and may be constituted by two or more kinds of films. For example, it is conceivable to form the light transmission preventing film 124 by appropriately combining a film having a high reflectance, a film having a low transmittance, a film having a high insulating property, and the like.

  The light transmission preventing film 124 is preferably formed with a thickness of 20 to 100 nm. If the film thickness is 20 nm or more, the light transmission preventing effect by reflection can be expected. Moreover, if the film thickness is 60 nm or more, the light transmission preventing film 124 can be expected to have a light transmission preventing effect by absorbing light and attenuating light intensity. On the other hand, when the film thickness is greater than 100 nm, the opening area of the hole 122 is reduced due to the thickness of the light transmission preventing film 124, so that the sensitivity characteristic of the solid-state imaging device is deteriorated. In order to improve the sensitivity characteristics, it is desirable that the light transmission preventing film 124 is thin.

  On the third wiring layer 121, a 150 nm thick interlayer film 125 made of a silicon oxide film, a 200 nm thick protective film 126 made of a silicon nitride film, and a color filter 127 are formed in this order from the silicon substrate 100 side. Further, a microlens 128 is formed at a position corresponding to the light receiving unit 101.

  2 to 4 are plan views showing the wiring structure of the solid-state imaging device according to the first embodiment. As shown in FIGS. 2 to 4, the solid-state imaging device has a region denoted by reference numeral 130 as one pixel portion, and includes a light receiving portion 101 of an activation region, a pixel portion transistor formation region 131, and an element isolation region 132. Although not shown, various transistor gate electrodes such as a transfer transistor, an amplifying transistor, and a resetting transistor are also provided.

  The light receiving unit 101 has a short side length of 900 nm and a long side length of 1500 nm. The width L1 of the element isolation region 132 is 200 nm. The first copper wiring 111 is formed in a pattern as shown in FIG. 2, and is connected to the pixel portion transistor formation region 131 and the various transistor gate electrodes through a first connection hole (not shown). The first copper wiring 111 has a width of 160 nm, a shortest distance L2 between the wirings of 180 nm, and a shortest width L3 of a gap with the hole 122 of 80 nm. The degree of freedom of mask alignment by the exposure apparatus between the first copper wiring 111 and the hole 122 is designed to be within 60 nm. The first light transmission preventing portion 124 a is formed along the inner peripheral surface of the hole 122.

  The second copper wiring 115 is formed in a pattern as shown in FIG. 3 and has a width of 160 to 200 nm, a shortest distance L4 between the wirings of 180 nm, and a shortest width L5 of the gap with the hole 122 of 80 nm. Note that the degree of freedom of mask alignment by the exposure apparatus between the second copper wiring 115 and the hole 122 is designed to be within 60 nm. The second light transmission preventing portion 124 b is formed along the inner peripheral surface of the hole portion 122.

  The third copper wiring 119 has a pattern as shown in FIG. 4 and has a width of 200 to 300 nm, a shortest distance between the wirings of 1400 to 1500 nm, and a width of the gap with the hole 122 of 100 to 150 nm. . The degree of freedom of mask alignment by the exposure apparatus between the third copper wiring 119 and the hole 122 is designed to be within 60 nm. The third light transmission preventing portion 124 c is formed along the inner peripheral surface of the hole 122.

<Method for Manufacturing Solid-State Imaging Device>
In the method for manufacturing a solid-state imaging device according to the present invention, first, the light receiving unit 101 and the detection unit 102 are formed in the silicon substrate 100 by ion implantation or the like, and further, the surface P-type layer 103 is formed on the light receiving unit 101. Then, a gate interlayer insulating film 104 and a gate electrode 105 are formed on the upper surface of the silicon substrate 100.

  Next, after sequentially forming a silicon oxide film and a silicon nitride film, the upper part of the light receiving part 101 and a part on the gate electrode 105 are masked by patterning formation by lithography, and masked by anisotropic dry etching. The side wall 106 and the antireflection film 107 are formed by selectively removing the portions of the silicon oxide film and silicon nitride film that are not present.

  Next, a silicon nitride film is formed, a mask in which the upper part of the light receiving part 101 is opened by patterning formation using a lithography technique, and a silicon nitride film in a region corresponding to the upper part of the light receiving part 101 is selectively removed by dry etching, A stopper film 108 is formed. By selectively removing the region above the light receiving portion 101 of the silicon nitride film of the antireflection film 107 by dry etching at that time, the antireflection film 107 has a desired thickness (30 To 70 nm).

  Next, a silicon nitride film is formed, and a stopper film 108 is formed in a region other than the upper part of the light receiving unit 101 by patterning formation by dry lithography and dry etching.

  Subsequently, a BPSG film is formed by a CVD (Chemical Vapor Deposition) method, the surface of the BPSG film is reflowed, for example, by annealing at 900 ° C. for 30 seconds, and further planarized by CMP (Chemical Mechanical Polishing) to be premetalized. An interlayer insulating film 109 is formed. In the premetal interlayer insulating film 109, first connection holes (not shown) are formed on the detection unit 102, the gate electrode 105, and the source / drain regions used in the transistors of the peripheral circuit. The first connection hole is formed by forming a contact hole in the pre-metal interlayer insulating film 109 by dry etching, then filling in tungsten (W), which is a metal material, and flattening by CMP polishing.

  Next, the first wiring layer 113 is formed. For the first wiring layer 113, first, a silicon oxide film to be the first interlayer insulating film 110 is formed, and the first copper wiring 111 is provided by a single damascene method. At that time, a barrier metal film (not shown) made of a laminated film of tantalum (Ta) and tantalum nitride (TaN) is formed between the first interlayer insulating film 110 and the first copper wiring 111 by a CVD method or a sputtering method. Form. Thereafter, a silicon nitride film to be the first diffusion preventing film 112 is formed, and the first wiring layer 113 is completed.

  Next, the first light transmission preventing portion 124a of the light transmission preventing film 124 is formed. FIG. 5 is a view for explaining the method of forming the first light transmission preventing portion according to the first embodiment. First, a region (a region corresponding to a light receiving portion) of the first diffusion prevention film 112, the first interlayer insulating film 110, and the premetal interlayer insulating film 109 above the light receiving portion 101 is selectively removed by patterning and dry etching using a lithography technique. Hole 122 is formed (FIG. 5A). Next, a silicon nitride film is formed by CVD (FIG. 5B), and the silicon nitride film on the antireflection film 107 and the first diffusion prevention film 112 is selectively removed by anisotropic dry etching. Then, only the silicon nitride film on the inner peripheral surface of the hole 122 is left, and the first light transmission preventing portion 124a is formed (FIG. 5C).

  As a dry etching method for forming the light transmission preventing film 124, it is desirable to employ a dry etching method having high anisotropy. This method is suitable for removing the silicon nitride film at the bottom of the hole 122 (silicon nitride film on the antireflection film 107) without removing the silicon nitride film on the inner peripheral surface of the hole 122.

  Next, a silicon oxide film to be the second interlayer insulating film 114 is formed, the surface of the silicon oxide film is planarized by CMP, and covered with a barrier metal film (not shown) by the via first method and dual damascene method. The second copper wiring 115 is provided, and a silicon nitride film to be the second diffusion prevention film 116 is further formed.

  Next, the second light transmission preventing portion 124b of the light transmission preventing film 124 is formed. FIG. 6 is a diagram for explaining a method of forming the second light transmission preventing portion according to the first embodiment. First, a hole 122 is formed by selectively removing a region (a region corresponding to a light receiving portion) of the second diffusion prevention film 116 and the second interlayer insulating film 114 above the light receiving portion 101 by patterning and dry etching using a lithography technique. (FIG. 6A). Next, a silicon nitride film is formed by the CVD method, and the silicon nitride film on the antireflection film 107 and the second diffusion prevention film 116 is selectively removed by anisotropic dry etching, so that the holes 122 are formed. Only the silicon nitride film on the inner peripheral surface is left, and the second light transmission preventing portion 124b is formed (FIG. 6B).

  Next, a silicon oxide film to be the third interlayer insulating film 118 is formed, the surface of the silicon oxide film is planarized by CMP, and covered with a barrier metal film (not shown) by the via first method and dual damascene method. The third copper wiring 119 is provided, and a silicon nitride film to be the third diffusion prevention film 120 is further formed.

  Next, the third light transmission preventing portion 124c of the light transmission preventing film 124 is formed. FIG. 7 is a view for explaining the method of forming the third light transmission preventing portion according to the first embodiment. First, a hole 122 is formed by selectively removing a region above the light receiving portion 101 of the third diffusion prevention film 120 and the third interlayer insulating film 118 (region corresponding to the light receiving portion) by patterning and lithography using a lithography technique. (FIG. 7A). Next, a silicon nitride film is formed by a CVD method, and the silicon nitride film on the antireflection film 107 and the third diffusion prevention film 120 is selectively removed by anisotropic dry etching, so that the holes 122 are formed. A third light transmission preventing portion 124c is formed leaving only the silicon nitride film on the inner peripheral surface (FIG. 7B).

  The light transmission preventing film 124 may be formed at the same time instead of individually forming the light transmission preventing portions 124a to 124c. FIG. 8 is a diagram for explaining a method of forming a light transmission preventing film according to a modification of the first embodiment. In that case, for example, as shown in FIG. 8, the third diffusion prevention film 120 is formed without forming the light transmission preventing portions 124a to 124c (FIG. 8A), and then silicon nitride is formed by CVD. A film is formed (FIG. 8B), and the silicon nitride film on the antireflection film 107 and the third diffusion prevention film 120 is selectively removed by anisotropic dry etching, and the inside of the hole 122 is formed. It is conceivable to form the light transmission preventing film 124 on the entire peripheral surface at once (FIG. 8C).

  After the formation of the light transmission preventing film 134, a silicon oxide film is formed to form an interlayer film 125. At this time, the light guide member 123 is filled by forming a silicon oxide film in the hole 122. Further, after forming a protective film 126 by forming a silicon nitride film and forming a color filter 127, a microlens 128 is formed above the light receiving unit 101. Note that a planarization layer (not shown) made of an acrylic resin may be formed between the protective film 126 and the color filter 127, or between the color filter 127 and the microlens 128.

[Second Embodiment]
FIG. 9 is a cross-sectional view schematically showing the structure around the light receiving part of the solid-state imaging device according to the second embodiment. As shown in FIG. 9, the solid-state imaging device according to the second embodiment is mainly different from the solid-state imaging device according to the first embodiment in the configuration of the light transmission preventing film 224. Since the other configuration is substantially the same as that of the solid-state imaging device according to the first embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The light transmission preventing film 224 according to the second embodiment is similar to the light transmission preventing film 124 according to the first embodiment, and the first light transmission preventing part 224a, the second light transmission preventing part 224b, and the third light transmission preventing film. Although it consists of the part 224c, it is different in that each light transmission preventing part 224a to 224c is not connected and separated.

  More specifically, the light transmission preventing portions 224a to 224c according to the second embodiment are shorter on the lower side (silicon substrate 100 side) than the light transmission preventing portions 124a to 124c according to the first embodiment. The lower end of the first light transmission preventing portion 224a is not in contact with the antireflection film 107 and the stopper film 108, and the lower end of the second light transmission preventing portion 224b is not in contact with the upper end of the first light transmission preventing portion 224a. The lower end of the third light transmission preventing portion 224c is not in contact with the upper end of the second light transmission preventing portion 224b.

  Also in the solid-state imaging device according to the second embodiment, since the light transmission preventing film 224 is formed between the inner peripheral surface of the hole 122 and the light guide member 123, the light incident on the light guide member 123 is adjacent to the solid-state image sensor. Difficult to leak into pixels. The light transmission preventing film 224 is preferably a film using an insulating material such as a silicon nitride film, a silicon carbide film, or an oxynitride film, and may be composed of two or more kinds of films. The light transmission preventing film 124 according to the first embodiment is preferably formed in a film thickness of 20 to 100 nm.

  FIG. 10 is a diagram for explaining a method of forming the first light transmission preventing portion according to the second embodiment. As shown in FIG. 10, the first light transmission preventing portion 224 a is formed by first receiving light receiving portions of the first diffusion preventing film 112, the first interlayer insulating film 110, and the premetal interlayer insulating film 109 by patterning and dry etching using a lithography technique. A hole 122 is formed by removing an area (an area corresponding to the light receiving part) above 101 (FIG. 10A).

  At that time, the premetal interlayer insulating film 109 is not completely removed, and a predetermined thickness is left. In this way, by forming the hole 122 shallowly while leaving a predetermined thickness in the premetal interlayer insulating film 109, it is possible to prevent a filling defect (void) when forming the silicon oxide film in the hole 122. it can.

  Next, a silicon nitride film is formed by CVD (FIG. 10B), and the silicon nitride film on the antireflection film 107 and the first diffusion prevention film 112 is selectively removed by anisotropic dry etching. Then, only the silicon nitride film on the inner peripheral surface of the hole 122 is left, and the first light transmission preventing portion 224a whose lower end is not in contact with the antireflection film 107 and the stopper film 108 is formed (FIG. 10C).

  When forming the second light transmission preventing portion 224a and the third light transmission preventing portion 224c, as in the case of the first light transmission preventing portion 224a, the second interlayer insulating film 114 and the third interlayer insulating film 118 are formed. When the hole 122 is formed in the region above the light receiving unit 101 (the region corresponding to the light receiving unit), a silicon oxide film is formed in the hole 122 by forming the hole 122 shallow with a predetermined thickness remaining. To prevent improper embedding.

[Third Embodiment]
FIG. 11 is a cross-sectional view schematically showing the structure around the light receiving unit of the solid-state imaging device according to the third embodiment. As shown in FIG. 11, the solid-state imaging device according to the third embodiment is mainly different from the first embodiment in that the third light transmission preventing portion 124c, the third diffusion preventing film 120, and the interlayer film 125 are not formed. This is different from the solid-state imaging device. Since the other configuration is substantially the same as that of the solid-state imaging device according to the first embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The light transmission preventing film 324 according to the third embodiment includes a first light transmission preventing portion 324a and a second light transmission preventing portion 324b, and there is no third light transmission preventing portion. Also in the solid-state imaging device according to the third embodiment, since the light transmission preventing film 324 is formed between the inner peripheral surface of the hole 122 and the light guide member 123, the light incident on the light guide member 123 is adjacent. Difficult to leak into pixels. The light transmission preventing film 324 is preferably a film using an insulating material such as a silicon nitride film, a silicon carbide film, or an oxynitride film, and may be composed of two or more kinds of films. The light transmission preventing film 124 according to the first embodiment is preferably formed with a film thickness of 20 to 100 nm.

  In the method of manufacturing the solid-state imaging device according to the third embodiment, after the third copper wiring 119 is formed, the protective film 126 is provided without forming the third diffusion prevention film and the interlayer film. Since the protective film 126 is made of a silicon nitride film made of the same material as the third diffusion preventing film 120, it also serves as a copper diffusion preventing film. Since the protective film 126 does not remove the region above the light receiving unit 101, the protective film 126 does not cause diffraction scattering of incident light.

  In the solid-state imaging device according to the third embodiment, it is not necessary to form the third light transmission preventing portion, and only the first light transmission preventing portion 324a and the second light transmission preventing portion 324b need be formed. Is advantageous.

[Modification]
As described above, the solid-state imaging device and the manufacturing method thereof according to the present invention have been specifically described based on the embodiments. However, the solid-state imaging device and the manufacturing method thereof according to the present invention are not limited to the above-described embodiments.

  For example, the solid-state imaging device according to the present invention may have a configuration in which a part of the configuration of the solid-state imaging device according to the first to third embodiments is combined. Moreover, although the solid-state imaging device according to the first to third embodiments is a MOS type solid-state imaging device including a pixel unit and a detection unit, the technology of the present invention can be applied even in the case of a CCD. The solid-state imaging device according to the first to third embodiments has a three-layer wiring layer. However, the solid-state imaging device according to the present invention has a one-layer structure, a two-layer structure, or a four-layer structure. It may be above. Further, a film other than the light transmission preventing film may be formed between the light transmission preventing film and the light guide member and between the light transmission preventing film and the inner peripheral surface of the hole.

  Since the solid-state imaging device according to the present invention has good color reproducibility, it is mainly used for high-definition single-lens reflex digital still cameras, consumer and professional digital still cameras, and high-definition video imaging. It is useful for solid-state image sensors for consumer and broadcast equipment.

Sectional drawing which shows typically the structure around the light-receiving part of the solid-state image sensor concerning the 1st Embodiment of this invention. The top view which shows the wiring structure of the solid-state image sensor which concerns on 1st Embodiment The top view which shows the wiring structure of the solid-state image sensor which concerns on 1st Embodiment The top view which shows the wiring structure of the solid-state image sensor which concerns on 1st Embodiment The figure for demonstrating the formation method of the 1st light transmission prevention part which concerns on 1st Embodiment. The figure for demonstrating the formation method of the 2nd light transmission prevention part which concerns on 1st Embodiment. The figure for demonstrating the formation method of the 3rd light transmission prevention part which concerns on 1st Embodiment. The figure for demonstrating the formation method of the light transmission prevention film which concerns on the modification of 1st Embodiment. Sectional drawing which shows typically the structure around the light-receiving part of the solid-state image sensor concerning 2nd Embodiment The figure for demonstrating the formation method of the 1st light transmission prevention part which concerns on 2nd Embodiment. Sectional drawing which shows typically the structure around the light-receiving part of the solid-state image sensor which concerns on 3rd Embodiment. Sectional drawing which shows typically the structure around the light-receiving part of the conventional solid-state image sensor

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Semiconductor substrate 101 Light-receiving part 107 Antireflection film 110,114,118 Interlayer insulation film 111,115,119 Copper wiring 112,116,120 Diffusion prevention film 113,117,121 Wiring layer 122 Hole part 123 Light guide member 124 Light transmission Prevention film 124a, 124b, 124c Light transmission prevention part

Claims (10)

A wiring layer in which an interlayer insulating film, a copper wiring, and a diffusion preventing film for preventing copper diffusion are laminated on the main surface of the semiconductor substrate on which the light receiving portion for performing photoelectric conversion is formed on the main surface has a single layer or a multilayer structure. A solid-state imaging device formed and filled with a light guide member in a hole provided by removing a region corresponding to a light receiving portion of the wiring layer,
A solid-state imaging device, wherein a light transmission preventing film is formed between an inner peripheral surface of the hole and the light guide member. The solid-state imaging device according to claim 1, wherein the light transmission preventing film includes at least one of a silicon nitride film, a silicon carbide film, and an oxynitride film. The solid-state imaging device according to claim 1, wherein the light transmission preventing film is composed of two or more kinds of films. 4. The solid-state imaging device according to claim 1, wherein the light transmission preventing film is formed with a thickness of 20 to 100 nm. The said hole part penetrates the said wiring layer in the thickness direction, and the said light transmission prevention film is formed over the whole internal peripheral surface of the said hole part. Solid-state image sensor. 6. The solid-state imaging device according to claim 1, wherein the diffusion prevention film includes at least one of a silicon nitride film and a silicon carbide film. Forming a light receiving portion for performing photoelectric conversion on the main surface of the semiconductor substrate;
Forming a wiring layer in a single layer or a multilayer structure in which an interlayer insulating film, a copper wiring, and a diffusion preventing film for preventing copper diffusion are laminated above the main surface of the semiconductor substrate;
Removing the region corresponding to the light receiving portion of the wiring layer to provide a hole; and
Forming a light transmission preventing film on the inner peripheral surface of the hole,
And a step of filling the hole with a light guide member. 8. The method of manufacturing a solid-state imaging device according to claim 7, wherein the light transmission preventing film is formed by anisotropic dry etching. After the step of forming the light receiving portion and before the step of forming the wiring layer,
9. The method according to claim 7, further comprising a step of forming an antireflection film above the light receiving portion and performing dry etching with a mask having an opening corresponding to the light receiving portion to thin the antireflection film. Manufacturing method of solid-state image sensor. 10. The method of manufacturing a solid-state imaging device according to claim 9, wherein the antireflection film includes a silicon nitride film, and the antireflection film is thinned by dry etching the silicon nitride film.

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