JP2011142234A - Solid-state image pickup element and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state image pickup element which achieves compatibility between security of light-shielding performance and improvement in light gathering efficiency. <P>SOLUTION: The solid-state image pickup element 100 has: photoelectric conversion regions 2a which receive light from a subject and generate electric charges corresponding to the quantity of the light; and photoelectric conversion regions 2b which detect a black level, those regions being formed in a substrate 1. Further, the solid-state image pickup element includes charge transfer electrodes 3a constituting CCDs provided corresponding to the photoelectric conversion regions 2a and 2b, a light shield film 8 shielding the charge transfer electrodes 3a and photoelectric conversion regions 2b from light and having openings formed over the photoelectric conversion regions 2a, and conductive members 5 provided over the substrate 1 between the photoelectric conversion regions 2b and light shield film 8. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device and a manufacturing method thereof.

  FIG. 8 is a schematic sectional view of a conventional CCD (Charge Coupled Device) type solid-state imaging device. The solid-state image sensor shown in FIG. 8 includes a plurality of photoelectric conversion elements (PD) 102 formed in a semiconductor substrate 101.

  The photoelectric conversion element 102 includes an effective photoelectric conversion element (indicated by PD in the figure) for generating and accumulating charges according to light from the subject, and OB photoelectric conversion for detecting the optical black level. Element (indicated by OB in the figure). The area where the effective photoelectric conversion element 102 is disposed is the effective area 120, and the area where the OB photoelectric conversion element 102 is disposed is the OB area 130.

  On the left side of each photoelectric conversion element 102 in the semiconductor substrate 101, a charge transfer channel 103 for transferring charges generated and accumulated in the photoelectric conversion element 102 is formed. A transfer electrode 104 is formed on the charge transfer channel 103 via a gate insulating film 110, and the charge transfer channel 103 and the transfer electrode 104 constitute a CCD.

  A light shielding film 105 for shielding the CCD and OB photoelectric conversion element 102 is formed above the semiconductor substrate 101. An opening is formed in the light shielding film 105 above the effective photoelectric conversion element 102 so that light enters the effective photoelectric conversion element 102. No opening is formed in the upper part of the OB photoelectric conversion element 102 so that light does not enter the OB photoelectric conversion element 102.

  An interlayer insulating film 106 is formed on the light shielding film 105, and an intralayer lens 107 is formed thereon. A planarizing film 108 is formed on the in-layer lens 107, and a color filter 109 is formed thereon. A microlens (not shown) is formed on the color filter 109.

  The solid-state imaging device having such a configuration needs to optimize the shape of the in-layer lens 107 and bring the color filter and the microlens as close to the semiconductor substrate 101 as possible in the effective region 120 in order to increase the light collection efficiency. In order to achieve these, it is necessary to make the light shielding film 105 as thin as possible.

  On the other hand, in the OB region 130, it is necessary to reliably prevent light from entering the OB photoelectric conversion element 102. For this purpose, it is necessary to increase the light shielding performance by increasing the thickness of the light shielding film 105. As described above, the requirements for the thickness of the light shielding film 105 in the effective area 120 and the OB area 130 are contradictory.

  In order to improve the light shielding performance of the OB photoelectric conversion element 102, a method of providing another light shielding film on the light shielding film 105 above the OB photoelectric conversion element 102 is also known.

  However, this method not only increases the number of manufacturing steps, but also contradicts the demand for bringing color filters and microlenses as close to the semiconductor substrate 101 as possible.

  Patent Document 1 proposes a configuration in which the thickness of the light shielding film in the OB region is made larger than the thickness of the light shielding film in the effective region. However, this configuration also requires the manufacturing process to be increased because the light shielding film in the OB region needs to be formed in two steps. In addition, this is also in conflict with the demand to bring the color filter and microlens as close to the semiconductor substrate 101 as possible.

JP 2009-272747 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solid-state imaging device capable of ensuring both light shielding performance and improvement in light collection efficiency and a method for manufacturing the same.

  The solid-state imaging device of the present invention has a first region formed on a semiconductor substrate that receives light from a subject and generates a charge corresponding to the amount of light, and a second region for detecting a black level. A CCD type solid-state imaging device, comprising: a charge transfer electrode constituting a CCD provided corresponding to the first region and the second region; and a light shield for shielding the charge transfer electrode and the second region A light shielding film having an opening formed above the first region, and a conductive member provided above the semiconductor substrate between the second region and the light shielding film.

  The method for manufacturing a solid-state imaging device according to the present invention includes a first region for detecting a black level and a first region formed on a semiconductor substrate that receives light from a subject and generates a charge corresponding to the amount of light. A method of manufacturing a CCD type solid-state imaging device having a region, comprising: forming a charge transfer electrode constituting the CCD corresponding to the first region and the second region above the semiconductor substrate; A light shielding film for shielding light from the charge transfer electrode and the second region, the step of forming a light shielding film having an opening above the first region; and between the second region and the light shielding film Forming a conductive member above the semiconductor substrate.

  ADVANTAGE OF THE INVENTION According to this invention, the solid-state image sensor which can satisfy | fill both ensuring of light-shielding performance and improvement of condensing efficiency can be provided, and its manufacturing method.

1 is a schematic plan view showing a schematic configuration of a solid-state imaging device for explaining an embodiment of the present invention. Sectional schematic diagram of the AA line in the solid-state image sensor shown in FIG. The figure which showed the example which comprised the charge transfer electrode 3a with the metal silicide in the solid-state image sensor shown in FIG. FIG. 2 shows a first modification of the solid-state imaging device shown in FIG. 1, and corresponds to the cross section shown in FIG. Sectional schematic diagram in each step of the charge transfer electrode forming step of the solid-state imaging device shown in FIG. FIG. 2 shows a second modification of the solid-state imaging device shown in FIG. 1, and corresponds to the cross section shown in FIG. FIG. 9 shows a third modification of the solid-state imaging device shown in FIG. 1, and corresponds to the cross section shown in FIG. Cross-sectional schematic diagram of a conventional CCD solid-state image sensor

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic plan view showing a schematic configuration of a solid-state imaging device for explaining an embodiment of the present invention. A solid-state imaging device 100 shown in FIG. 1 includes a plurality of photoelectric conversion regions (photoelectric conversion regions 2a, photoelectric conversion regions 2b), a vertical charge transfer unit 3, a charge readout region 4, a horizontal charge transfer unit 30, and an output unit. 40.

  Each of the photoelectric conversion region 2a and the photoelectric conversion region 2b is a pn junction photodiode formed in, for example, a semiconductor substrate. When receiving light, the photoelectric conversion region 2a and the photoelectric conversion region 2b are regions that generate and accumulate charges corresponding to the amount of light. The plurality of photoelectric conversion regions including the photoelectric conversion region 2a and the photoelectric conversion region 2b are arranged in a two-dimensional shape (square lattice shape in the example in the figure) in the horizontal direction X of the semiconductor substrate and the vertical direction Y orthogonal thereto. Yes.

  The photoelectric conversion region 2a is a photoelectric conversion region in which light from a subject can enter. The photoelectric conversion region 2b is a photoelectric conversion region in which light is not incident to detect a black level. In FIG. 1, the letters “OB” are written in the photoelectric conversion region 2b.

  The region in which the photoelectric conversion region 2a is disposed is described as an effective region 50, and the region in which the photoelectric conversion region 2b is disposed is described as an OB region 60. In FIG. 1, the OB area 60 is provided only on one side of the effective area 50, but may be provided on both sides or around the effective area 50.

  The vertical charge transfer unit 3 is provided corresponding to a column composed of a plurality of photoelectric conversion regions arranged in the vertical direction Y, and the charge read from each photoelectric conversion region of the corresponding column via the charge read region 4 is vertically Transfer in direction Y. The vertical charge transfer unit 3 includes a charge transfer channel formed in a semiconductor substrate and a charge transfer electrode provided above the charge transfer channel.

  The horizontal charge transfer unit 30 transfers the charges transferred from the plurality of vertical charge transfer units 3 in the horizontal direction X.

  The output unit 40 converts the charge transferred from the horizontal charge transfer unit 30 into a signal corresponding to the charge amount and outputs the signal.

  2 is a schematic cross-sectional view taken along the line AA in the solid-state imaging device shown in FIG. Photoelectric conversion regions 2a and 2b are formed in a semiconductor substrate 1 made of silicon or the like, and a vertical charge transfer unit corresponding to the photoelectric conversion regions 2a and 2b is slightly spaced to the left of the photoelectric conversion regions 2a and 2b. 3 is formed.

  A gate insulating film 13 such as a silicon oxide film or an ONO film is formed on the semiconductor substrate 1, and a charge transfer electrode 3a that forms the vertical charge transfer unit 3 together with the charge transfer channel 3b is formed thereon. The charge transfer electrode 3a is formed above the charge transfer channel 3b. By controlling the voltage applied thereto, the potential of the charge transfer channel 3a can be controlled to transfer the charge in the vertical direction Y. ing.

  The charge transfer electrode 3a shown in the cross section shown in FIG. 2 is the same electrode extending in the horizontal direction X in plan view. The charge transfer electrodes 3a are long electrodes extending in the horizontal direction X, and the long electrodes are arranged in the vertical direction Y with a minute gap.

  On the gate insulating film 13 on the photoelectric conversion region 2b, the conductive member 5 that does not exist in the conventional configuration shown in FIG. 8 is formed.

  The conductive member 5 is an island-like member arranged at a distance from the charge transfer electrode 3a so as not to contact the charge transfer electrode 3a. The conductive member 5 is formed in the same process as the charge transfer electrode 3a, and is formed of the same material and in the same layer as the charge transfer electrode 3a. Here, the same layer means that the heights of the lower surface and the upper surface are the same.

  An insulating film 7 such as silicon oxide is formed around the charge transfer electrode 3 a in the effective region 50 and around the charge transfer electrode 3 a and the conductive member 5 in the OB region 60. The insulating film 7 has an opening above the photoelectric conversion region 2a. On the other hand, no opening is formed in the insulating film 7 above the photoelectric conversion region 2 b, and the insulating film 7 has a flat shape in the OB region 60.

  On the insulating film 7 and the gate insulating film 13, a light shielding film 8 made of tungsten or the like for shielding the CCD and the photoelectric conversion region 2 b corresponding to each of the photoelectric conversion regions 2 a and 2 b is formed. The light shielding film 8 has an opening formed above the photoelectric conversion region 2a, and light can enter the photoelectric conversion region 2a from the opening. On the other hand, no opening is formed in the light shielding film 8 above the photoelectric conversion region 2b so that light cannot enter the photoelectric conversion region 2b.

  In the effective region 50, since there is a gap between the insulating films 7, the light shielding film 8 has a shape recessed toward the substrate 1 above the photoelectric conversion region 2a. On the other hand, in the OB region 60, since the insulating film 7 is flat, the light shielding film 8 is also flat.

  In order to fix the potential of the conductive member 5, the conductive member 5 and the light shielding film 8 are electrically connected by the contact portion 6. The contact portion 6 is made of a conductive material and is buried in a through hole formed in the insulating film 7 on the conductive member 5.

  A BPSG film 9 is formed on the light shielding film 8. On the BPSG film 9, an inner lens 10 made of a nitride film or the like is formed.

  The in-layer lens 10 is provided above the photoelectric conversion areas 2a and 2b so as to efficiently guide light to the corresponding photoelectric conversion areas. The in-layer lens 10 includes a downward convex lens having a convex shape on the substrate 1 side and an upward convex lens having a convex shape on the color filter film 12 side (light incident side). In the OB region 60, the lower convex lens of the in-layer lens 10 is substantially absent due to the provision of the conductive member 5.

  A planarizing film 11 is formed on the in-layer lens 10, and a color filter film 12 is formed thereon. A microlens (not shown) is formed on the color filter film 12.

  Next, a method for manufacturing the solid-state imaging device configured as described above will be described. Since a generally known method is used as a method for manufacturing the element in the semiconductor substrate 1, the following description will start with the manufacturing process of the charge transfer electrode 3a.

  First, a conductive material is formed on the gate insulating film 13, and a resist pattern is formed on the formed conductive material. This resist pattern is set so that the material remains not only in the region where the charge transfer electrode 3a is to be formed but also in the region where the conductive member 5 is to be formed.

  Next, the conductive material film is etched using this resist pattern as a mask to form the charge transfer electrode 3a and the conductive member 5. Thereby, the charge transfer electrode 3a and the conductive member 5 can be formed of the same material and the same layer.

  Next, an insulating material is formed on the substrate 1 by a CVD (Chemical Vapor Deposition) method or the like, and the film of this insulating material is flattened by CMP (Chemical Mechanical Polishing) or the like. Next, an opening is formed above the photoelectric conversion region 2a of the planarized insulating material film. Thereby, the insulating film 7 is formed.

  Next, a through hole is formed in the insulating film 7 on the conductive member 5 by etching, and the contact portion 6 is formed by embedding a conductive material such as polysilicon or metal in the through hole.

  Next, a light shielding material such as tungsten is formed on the substrate 1. At this time, since the insulating film 7 is flat in the OB region 60, the light shielding material can be formed with a uniform thickness.

  Next, an opening is formed by photolithography above the photoelectric conversion region 2a of the light shielding material film to form the light shielding film 8. Next, BPSG is formed on the light shielding film 8 and reflowed.

  Next, a downward convex lens is formed on the BPSG film after reflow by a well-known method. For example, a downward convex lens is formed by forming a silicon nitride film on the BPSG film.

  At this time, since there is no step in the light shielding film 8 above the photoelectric conversion region 2b, a substantially downward convex lens is not formed above the photoelectric conversion region 2b.

  Next, an upward convex lens is formed by a well-known method, and a planarizing film 11 is formed thereon. Next, a color filter film 12 is formed on the planarizing film 11, and a microlens is formed on the color filter film 12.

  As described above, according to the solid-state imaging device 100, since the conductive member 5 is provided between the photoelectric conversion region 2b above the semiconductor substrate 1 and the light shielding film 8, the light shielding film 8 is flattened in the OB region 60. Can be made into any shape. For this reason, the light shielding performance of the light shielding film 8 in the OB region 60 can be improved. As a result, even if the light shielding film 8 is made thin in order to increase the light collection efficiency in the photoelectric conversion region 2a, it is possible to maintain the light shielding performance, and it is possible to realize a solid-state imaging device with high sensitivity and low noise. .

  In FIG. 2, the light shielding film 8 in the OB region 60 is completely flattened by forming the conductive member 5 in the same layer as the charge transfer electrode 3a. There may be a step.

  For example, the thickness of the conductive member 5 may be smaller than that of the charge transfer electrode 3a, and the light shielding film 8 may be formed to be slightly depressed above the photoelectric conversion region 2b. Even in this case, the flatness of the light shielding film 8 in the OB region 60 can be improved and the light shielding performance in the OB region 60 can be improved as compared to the configuration shown in FIG.

  In this case, the conductive member 5 may be formed not in the same process as the charge transfer electrode 3a but in a separate process. The conductive member 5 is not limited to this case, and may be formed in a separate process from the charge transfer electrode 3a. In the case of another process, it is not necessary to use the same material for the conductive member 5 as that for the charge transfer electrode 3a. When the charge transfer electrode 3a and the conductive member 5 are formed in the same process, it is not necessary to add a manufacturing process, and an increase in cost can be suppressed.

  Further, according to the solid-state imaging device 100, since the conductive member 5 and the light shielding film 8 are electrically connected, the conductive member is fixed by fixing the potential of the light shielding film 8 to a predetermined potential such as ground. The potential of 5 can also be fixed. As a result, it is possible to prevent the conductive member 5 from being charged up by the charge from the substrate and the like, and noise from being added to the signal read from the photoelectric conversion region 2b.

  The conductive member 5 may be electrically floated. In this case, the formation of the contact portion 6 is not necessary, so that an increase in manufacturing steps can be suppressed.

  Further, the light shielding performance of the photoelectric conversion region 2b can be further improved by forming the contact portion 6 from a light shielding material (for example, tungsten) and setting the size to cover the photoelectric conversion region 2b. It becomes.

  Since the contact portion 6 is formed by opening a through hole in the insulating film 7 on the conductive member 5, the height of the light shielding film 8 itself can be made equal to the conventional one. For this reason, by using this contact portion 6 also as a light shielding film, the light shielding performance can be improved without increasing the light shielding film 8, and the light shielding film 8 can be further reduced in thickness and collected in the photoelectric conversion region 2a. Light efficiency can be improved.

  Further, according to the solid-state imaging device 100, the light shielding film 8 is flat in the OB region 60, or the level difference is very small, so that the condensing of the inner lens above the photoelectric conversion region 2b is performed. The efficiency can be significantly reduced as compared with the intralayer lens above the photoelectric conversion region 2a. As a result, in addition to improving the light shielding performance by improving the flatness of the light shielding film 8, an effect of improving the light shielding performance by reducing the light collection efficiency of the inner lens above the photoelectric conversion region 2b can be obtained.

  Further, in the solid-state imaging device 100, since the inner lens 10 is provided above each photoelectric conversion region, the light collection efficiency in the photoelectric conversion region 2a is improved as compared with the case where the inner lens 10 is not provided. Can do.

  In the configuration in which the in-layer lens 10 is provided, if the light shielding film 8 is thinned to increase the light collection efficiency in the photoelectric conversion region 2a, the light collection effect by the in-layer lens 10 provided above the photoelectric conversion region 2b is caused. There is a possibility that the light shielding performance in the photoelectric conversion region 2b is lowered.

  However, in the solid-state imaging device 100, since the light shielding performance in the photoelectric conversion region 2b is improved by providing the conductive member 5, even when the light shielding film 8 is thinned, the light shielding performance of the photoelectric conversion region 2b. Can be secured to the minimum necessary. Therefore, it is possible to maintain the light shielding performance while improving the light collection efficiency as compared with the configuration in which the intralayer lens 10 is not provided.

  In the above description, the photoelectric conversion region 2b has the same configuration as the photoelectric conversion region 2a. However, the present invention is not limited to this. For example, nothing is provided in a portion corresponding to the photoelectric conversion region 2a of the OB region 60 (portion where the photoelectric conversion region 2b is formed), and only the semiconductor substrate 1 may be used. In this case, a signal corresponding to the charge accumulated in the charge transfer channel 3b adjacent to this region may be read as a black level signal instead of reading a signal from this region. Even in this configuration, if light enters the charge transfer channel 3b in the OB region 60, the black level cannot be detected accurately. For this reason, it is effective to improve the light shielding performance by the above-described configuration.

  In the above description, the intra-layer lens 10 is composed of two lenses, a downward convex lens and an upward convex lens. However, an effect of improving the light shielding performance due to a decrease in the light collection efficiency of the intra-layer lens in the photoelectric conversion region 2b is obtained. For the purpose, an upward convex lens is not essential.

  In the above description, the materials of the charge transfer electrode 3a and the conductive member 5 are not specified, but as this material, a metal such as polycrystalline silicon or tungsten, a metal silicide such as tungsten silicide, or the like is used. Can do.

  Since polycrystalline silicon is an electrode material generally used in CCD image sensors, it has an advantage that it can be manufactured on a general-purpose manufacturing line.

  Since the metal and the metal silicide themselves have a light shielding property, there is an advantage that the light shielding performance of the photoelectric conversion region 2b can be further improved. Further, by using metal and metal silicide, the resistance of the charge transfer electrode 3a can be reduced.

  FIG. 3 is a diagram showing an example in which the charge transfer electrode 3a is composed of two layers of metal silicide and polycrystalline silicon in the solid-state imaging device shown in FIG. 3 shows that the charge transfer electrode 3a has a two-layer structure of polycrystalline silicon 14a and metal silicide 14b, and the conductive member 5 has a two-layer structure of polycrystalline silicon 5a and metal silicide 5b. Same as the configuration. With such a configuration, the light shielding film 8 can be made thinner than the configuration of FIG. 2, and the light collection efficiency in the solid-state imaging region 2a can be further improved.

  Next, a modified example of the solid-state image sensor 100 will be described.

(First modification)
In the CCD type solid-state imaging device, a configuration is adopted in which terminals for supplying pulses from the outside are connected at the end of each charge transfer electrode. Since the charge transfer electrode has an elongated shape in the horizontal direction, simply supplying a pulse from the end part causes the pulse to be distorted at the center of the electrode, affecting the transfer characteristics.

  Therefore, a low-resistance conductive material (shunt wiring) is formed on the charge transfer electrode along the same, and the shunt wiring, the charge transfer electrode, The method of taking the electrical connection is adopted. The first modification is a configuration in which a part of the shunt wiring is left above the photoelectric conversion region 2b in the configuration in which the shunt wiring is provided.

  4 shows a first modification of the solid-state imaging device shown in FIG. 1, and corresponds to the cross section shown in FIG. In the solid-state imaging device shown in FIG. 4, a shunt wiring 15 and an insulating film 7 b are added between the insulating film 7 and the light shielding film 8, and the conductive member 5 is replaced with the conductive material 5 above the photoelectric conversion region 2 b. The configuration is the same as that shown in FIG.

  The shunt wiring 15 is provided on the insulating film 7 above the charge transfer electrode 3a, and is laid along the charge transfer electrode 3a. Contact portions 17 are formed at a plurality of positions in the horizontal direction of one charge transfer electrode 3a, and the charge transfer electrodes 3a and the shunt wiring 15 are electrically connected by the contact portions 17.

  The conductive member 16 is an island-like member disposed above the photoelectric conversion region 2b at a distance from the shunt wiring 15 so as not to contact the shunt wiring 15. The conductive member 16 is formed in the same process as the shunt wiring 15, and is formed of the same material and the same layer as the shunt wiring 15. Here, the same layer means that the heights of the lower surface and the upper surface are substantially the same. In FIG. 4, the insulating film 7 is flattened in the OB region 60 by filling the portion where the conductive member 5 shown in FIG. For this reason, it is possible to form the conductive member 16 and the shunt wiring 15 in the same layer.

  An insulating film 7 b is formed around the shunt wiring 15 in the effective region 50 and around the shunt wiring 15 and the conductive member 16 in the OB region 60. The insulating film 7b has an opening above the photoelectric conversion region 2a. On the other hand, no opening is formed in the insulating film 7b above the photoelectric conversion region 2b, and the insulating film 7b has a flat shape in the OB region 60.

  In order to fix the potential of the conductive member 16, the conductive member 16 and the light shielding film 8 are electrically connected by a contact portion 18. The contact portion 18 is made of a conductive material, and is buried in a through hole formed in the insulating film 7 b on the conductive member 16.

  Next, a method for manufacturing the solid-state imaging device shown in FIG. 4 will be described. Since a generally known method is used as a method for manufacturing the element in the semiconductor substrate 1, the following description will start with the manufacturing process of the charge transfer electrode.

  FIG. 5 is a schematic cross-sectional view in each step of the charge transfer electrode forming step of the solid-state imaging device shown in FIG. In FIG. 5, illustration of elements in the semiconductor substrate 1 is omitted.

  First, a conductive material such as polysilicon, which is a material of the charge transfer electrode 3a, is formed on the gate insulating film 13. Next, a resist pattern is formed on the formed conductive material. This resist pattern is set so that the material remains in the region where the charge transfer electrode 3a is to be formed.

  Next, the conductive material film is etched using this pattern as a mask to form the charge transfer electrode 3a.

  Next, an insulating material is formed on the substrate 1, and is flattened by CMP or the like to form an insulating film 7 '(FIG. 5A).

  Next, a through hole is formed in the insulating film 7 ′ on a part of the charge transfer electrode 3a, and a contact material 17 is formed by filling a conductive material such as tungsten, which is a refractory metal (FIG. 5B). . A barrier metal layer such as titanium nitride (TiN) or tungsten nitride (WN) is used to prevent an increase in contact resistance between the charge transfer electrode 3a and the contact portion 17 formed of a conductive material of a refractory metal. May be provided.

  Next, a material (for example, tungsten) of the shunt wiring 15 is formed on the insulating film 7 '. At this time, a barrier metal layer such as titanium nitride (TiN) or tungsten nitride (WN) may be provided between the contact portion 17 and the shunt wiring 15 in order to prevent an increase in contact resistance. Next, a resist pattern is formed on the deposited material. This resist pattern is set so that the material remains in the region where the shunt wiring 15 and the conductive member 16 are to be formed.

  Next, the material film is etched using this pattern as a mask to form the shunt wiring 15 and the conductive member 16.

  Next, an insulating material is formed on the insulating film 7 ′, the shunt wiring 15, and the conductive member 16, and is flattened by CMP or the like to form the insulating film 7 b ′ (FIG. 5C). Next, openings are formed in portions of the insulating films 7 'and 7b' above the photoelectric conversion region 2a to form the insulating films 7 and 7b (FIG. 5D).

  Thereafter, a through hole is formed in the insulating film 7b on the conductive member 16, and a conductive material is filled therein to form the contact portion 18. Then, the light shielding film 8 is formed on this, and the film above it is formed to obtain the solid-state imaging device shown in FIG.

  As described above, according to the solid-state imaging device shown in FIG. 4, the provision of the conductive member 16 can improve the flatness of the light shielding film 8 in the OB region 60. The same effect as described in the solid-state image sensor can be obtained. In particular, since the shunt wiring 15 uses a low-resistance metal material, the conductive member 16 can have light shielding performance, and the light shielding performance of the photoelectric conversion region 2b can be improved.

  In the configuration of FIG. 4 as well, the light shielding performance can be further improved by configuring the contact portion 18 with a light shielding material (such as tungsten) and increasing the area thereof.

  In the configuration of FIG. 4, the conductive member 16 may be formed in a separate process from the shunt wiring 15. In the case of a separate process, the material need not be the same as that of the shunt wiring 15. By forming the conductive member 16 and the shunt wiring 15 in the same process, it is not necessary to add a manufacturing process, so that an increase in cost can be suppressed.

(Second modification)
6 shows a second modification of the solid-state imaging device shown in FIG. 1, and corresponds to the cross section shown in FIG. The solid-state imaging device shown in FIG. 6 is a combination of the configuration shown in FIG. 3 and the configuration shown in FIG.

  That is, in the configuration shown in FIG. 4, the charge transfer electrode 3a has a two-layer structure of polycrystalline silicon 14a and metal silicide 14b, and a conductive member is formed in the insulating film 7 between the photoelectric conversion region 2b and the conductive member 16. 5 is added, and the conductive member 5 and the conductive member 16 are electrically connected by the contact portion 6.

  In the solid-state imaging device manufacturing method shown in FIG. 6, in the step of FIG. 5A shown in FIG. 5, the charge transfer electrode 3a is formed in a two-layer structure and patterned so as to leave a conductive material also above the photoelectric conversion region 2b. Thus, the charge transfer electrode 3a and the conductive member 5 are formed.

  Next, an insulating film 7 ′ is formed, and through holes are formed in the insulating film 7 ′ on the conductive member 5 and the insulating film 7 ′ on a part of the charge transfer electrode 3a, and a conductive material is formed there. Is embedded to form contact portions 6 and 17.

  Thereafter, the shunt wiring 15 and the conductive member 16 are simultaneously formed on the insulating film 7 ′, and then the insulating film 7b ′ is formed to form the contact portion 18, and openings are formed in the insulating films 7 ′ and 7b ′. After the formation, the light shielding film 8 may be formed.

  According to the configuration shown in FIG. 6, since there are two conductive members 5 and 16 above the photoelectric conversion region 2b, the photoelectric conversion region can be obtained by making both of them light-shielding. The light shielding performance of 2b can be greatly improved.

(Third modification)
FIG. 7 shows a third modification of the solid-state imaging device shown in FIG. 1, and corresponds to the cross section shown in FIG. The solid-state imaging device shown in FIG. 7 has the same configuration as that shown in FIG. 6 except that the contact portion 6 is changed to a contact portion 6 ′.

  The contact portion 6 ′ has the same function as the contact portion 6, but is different in that its area is increased so as to cover the photoelectric conversion region 2 b and the material thereof is light-shielding (for example, tungsten).

  With this configuration, the light shielding performance of the photoelectric conversion region 2b can be further improved, and the light shielding film 8 can be further thinned to improve the light collection efficiency of the photoelectric conversion region 2a. Also in this configuration, the light shielding performance can be further improved by configuring the contact portion 18 with a light shielding material (tungsten or the like) and increasing its area.

  In the above description, the charge transfer electrode 3a has a single-layer electrode structure, but it may have a two-layer electrode structure. Even in this case, the light shielding film can be uniformly formed by flattening the insulating film covering the charge transfer electrode.

  As described above, the following items are disclosed in this specification.

  The disclosed solid-state imaging device has a first region formed on a semiconductor substrate for receiving light from a subject and generating a charge corresponding to the amount of light, and a second region for detecting a black level. A CCD type solid-state imaging device, comprising: a charge transfer electrode constituting a CCD provided corresponding to the first region and the second region; and a light shield for shielding the charge transfer electrode and the second region A light shielding film having an opening formed above the first region, and a conductive member provided above the semiconductor substrate between the second region and the light shielding film.

  With this configuration, the position of the upper surface of the light shielding film above the second region can be made higher than the position of the upper surface of the light shielding film above the first region. As a result, the flatness of the light shielding film in the region where the second region is arranged is improved as compared with the conventional case where both positions match, and the light shielding performance of the second region can be improved. it can. Further, since the conductive member can be formed in the same process as the charge transfer electrode, the light shielding performance can be improved without adding a special manufacturing process.

  In the disclosed solid-state imaging device, the conductive member is made of the same material as the charge transfer electrode and is formed in the same layer as the charge transfer electrode.

  With this configuration, since the conductive member and the charge transfer electrode can be formed in the same process, the object can be achieved without adding a manufacturing process.

  The disclosed solid-state imaging device further includes a wiring formed above the charge transfer electrode and electrically connected to the charge transfer electrode, and the conductive member is made of the same material as the wiring And is formed in the same layer as the wiring.

  With this configuration, since the conductive member and the wiring can be formed in the same process, the object can be achieved without adding a manufacturing process.

  The disclosed solid-state imaging device further includes a wiring formed above the charge transfer electrode and electrically connected to the charge transfer electrode, and the conductive member includes a first member and A second member provided above the first member, wherein the first member is made of the same material as the charge transfer electrode and is formed in the same layer as the charge transfer electrode. The second member is made of the same material as the wiring and is formed in the same layer as the wiring.

  With this configuration, the light shielding performance can be further improved by selecting a light shielding material as the first member and the second member.

  The disclosed solid-state imaging device includes a member that electrically connects them between the first member and the second member.

  With this configuration, the light shielding performance can be further improved by another member.

  The disclosed solid-state imaging device includes a connection portion that electrically connects the conductive member and the light shielding film.

  With this configuration, by connecting the light shielding film to a predetermined potential, the potential of the conductive member can be fixed, and the characteristics of the signal read from the second region can be stabilized.

  In the disclosed solid-state imaging device, the connection portion is formed of a light-shielding material and covers the second region.

  With this configuration, the light shielding performance can be improved by the connecting portion.

  In the disclosed solid-state imaging device, the conductive member is electrically floating.

  With this configuration, the object can be achieved without adding a manufacturing process.

  In the disclosed solid-state imaging device, the light shielding film in a region where the second region is disposed is flat.

  With this configuration, the light shielding film in the region where the second region is disposed is uniformly formed, so that the light shielding performance can be further improved.

  The disclosed solid-state imaging device includes an in-layer lens above the first region and above the second region.

  In a solid-state imaging device having an in-layer lens, it is difficult to further increase the light collection efficiency in the first region. However, according to this configuration, the light shielding film can be thinned, so that the light collection efficiency can be improved. it can.

  In the disclosed solid-state imaging device, the in-layer lens is a downward convex lens.

  In the disclosed solid-state imaging device, the conductive member is made of a light-shielding material.

  With this configuration, since the conductive member has a light shielding function, the light shielding performance of the second region can be further improved. For this reason, even if the light shielding film is further thinned to increase the light collection efficiency, the light shielding performance can be maintained.

  In the disclosed solid-state imaging device, the light-shielding material is made of metal or metal silicide.

  In the disclosed solid-state imaging device, the conductive member is made of a polycrystalline silicon material.

  With this configuration, the object can be achieved using a general manufacturing process.

  The disclosed method for manufacturing a solid-state imaging device includes a first region formed on a semiconductor substrate that receives light from a subject and generates a charge corresponding to the amount of light, and a second region for detecting a black level. A method of manufacturing a CCD type solid-state imaging device having a region, comprising: forming a charge transfer electrode constituting the CCD corresponding to the first region and the second region above the semiconductor substrate; A light shielding film for shielding light from the charge transfer electrode and the second region, the step of forming a light shielding film having an opening above the first region; and between the second region and the light shielding film Forming a conductive member above the semiconductor substrate.

  In the disclosed method for manufacturing a solid-state imaging device, the conductive member is formed in the same process as the charge transfer electrode.

  The disclosed method for manufacturing a solid-state imaging device further includes a step of forming a wiring electrically connected to the charge transfer electrode above the charge transfer electrode, and the conductive member is formed in the same step as the wiring. Form.

  The disclosed method for manufacturing a solid-state imaging device further includes a step of forming a wiring electrically connected to the charge transfer electrode above the charge transfer electrode, wherein the conductive member is a first member. And a second member provided above the first member, the first member is formed in the same step as the charge transfer electrode, and the second member is formed in the same step as the wiring .

  The disclosed method for manufacturing a solid-state imaging device includes a step of forming a member that electrically connects them between the first member and the second member.

  The disclosed method for manufacturing a solid-state imaging device includes a step of forming a connection portion that electrically connects the conductive member and the light shielding film.

  In the disclosed method for manufacturing a solid-state imaging device, the connection portion is formed of a light-shielding material and covers the second region.

  The manufacturing method of the disclosed solid-state imaging device includes a step of forming a flat insulating film that covers the charge transfer electrode, and in the step of forming the light shielding film, a light shielding material is formed on the insulating film, This is patterned to form the flat light shielding film in the region where the second region is disposed.

  The disclosed method for manufacturing a solid-state imaging device includes a step of forming an in-layer lens above the first region and above the second region after the light shielding film is formed.

  In the disclosed method for manufacturing a solid-state imaging device, the in-layer lens is a downward convex lens.

  In the disclosed method for manufacturing a solid-state imaging element, the conductive member is formed of a light-shielding material.

  In the disclosed method for manufacturing a solid-state imaging device, the light-shielding material is a metal or a metal silicide.

  In the disclosed method for manufacturing a solid-state imaging device, the conductive member is formed of a polycrystalline silicon material.

DESCRIPTION OF SYMBOLS 1 Substrate 2a, 2b Photoelectric conversion area | region 3a Charge transfer electrode 5 Conductive member 8 Light shielding film 100 Solid-state image sensor

Claims (27)

A CCD type solid-state imaging device formed on a semiconductor substrate and having a first region for receiving light from a subject and generating a charge corresponding to the amount of light and a second region for detecting a black level. And
A charge transfer electrode constituting a CCD provided corresponding to the first region and the second region;
A light-shielding film that shields the charge transfer electrode and the second region, wherein the light-shielding film has an opening formed above the first region;
A solid-state imaging device comprising: a conductive member provided above the semiconductor substrate between the second region and the light shielding film. The solid-state imaging device according to claim 1,
A solid-state imaging device in which the conductive member is made of the same material as the charge transfer electrode and is formed in the same layer as the charge transfer electrode. The solid-state imaging device according to claim 1,
Furthermore, the wiring formed above the charge transfer electrode, including a wiring electrically connected to the charge transfer electrode,
A solid-state imaging device, wherein the conductive member is made of the same material as the wiring and is formed in the same layer as the wiring. The solid-state imaging device according to claim 1,
Furthermore, the wiring formed above the charge transfer electrode, including a wiring electrically connected to the charge transfer electrode,
The conductive member includes a first member and a second member provided above the first member,
The first member is made of the same material as the charge transfer electrode, and is formed in the same layer as the charge transfer electrode,
The solid-state imaging device, wherein the second member is made of the same material as the wiring and is formed in the same layer as the wiring. The solid-state imaging device according to claim 4,
A solid-state imaging device comprising a member that electrically connects the first member and the second member. The solid-state imaging device according to any one of claims 1 to 5,
A solid-state imaging device comprising a connection portion for electrically connecting the conductive member and the light shielding film. The solid-state imaging device according to claim 6,
A solid-state imaging device, wherein the connection portion is made of a light-shielding material and covers the second region. The solid-state imaging device according to any one of claims 1 to 5,
A solid-state imaging device in which the conductive member is electrically floating. The solid-state imaging device according to any one of claims 1 to 8,
A solid-state imaging device in which the light shielding film in a region where the second region is disposed is flat. The solid-state imaging device according to any one of claims 1 to 9,
A solid-state imaging device including an intralayer lens above the first region and above the second region. The solid-state imaging device according to claim 10,
A solid-state imaging device in which the in-layer lens is a downward convex lens. The solid-state imaging device according to any one of claims 1 to 11,
A solid-state imaging device in which the conductive member is made of a light-shielding material. The solid-state imaging device according to claim 12,
A solid-state imaging device in which the light-shielding material is made of metal or metal silicide. The solid-state imaging device according to any one of claims 1 to 11,
A solid-state imaging device in which the conductive member is made of a polycrystalline silicon material. Manufacturing of CCD type solid-state imaging device formed on a semiconductor substrate and having a first region for receiving light from a subject and generating a charge corresponding to the amount of light and a second region for detecting a black level A method,
Forming a charge transfer electrode constituting the CCD corresponding to the first region and the second region above the semiconductor substrate;
Forming a light-shielding film that shields light from the charge transfer electrode and the second region, the light-shielding film having an opening above the first region;
And a step of forming a conductive member above the semiconductor substrate between the second region and the light shielding film. It is a manufacturing method of the solid-state image sensing device according to claim 15,
A method for manufacturing a solid-state imaging device, wherein the conductive member is formed in the same process as the charge transfer electrode. It is a manufacturing method of the solid-state image sensing device according to claim 15,
And a step of forming a wiring electrically connected to the charge transfer electrode above the charge transfer electrode,
A method for manufacturing a solid-state imaging device, wherein the conductive member is formed in the same process as the wiring. It is a manufacturing method of the solid-state image sensing device according to claim 15,
And a step of forming a wiring electrically connected to the charge transfer electrode above the charge transfer electrode,
The conductive member includes a first member and a second member provided above the first member,
Forming the first member in the same step as the charge transfer electrode;
A method for manufacturing a solid-state imaging device, wherein the second member is formed in the same process as the wiring. A method for producing a solid-state imaging device according to claim 18,
A method for manufacturing a solid-state imaging device, comprising: forming a member that electrically connects the first member and the second member. It is a manufacturing method of the solid-state image sensing device according to any one of claims 15-19,
A manufacturing method of a solid-state image sensing device provided with a process of forming a connection part which electrically connects the conductive member and the light-shielding film. A method for manufacturing a solid-state imaging device according to claim 20,
A method for manufacturing a solid-state imaging device, wherein the connection portion is formed of a light-shielding material and covers the second region. It is a manufacturing method of the solid-state image sensing device according to any one of claims 15 to 21,
Forming a flat insulating film covering the charge transfer electrode;
In the step of forming the light shielding film, a light shielding material is formed on the insulating film, and the light shielding material is patterned to form a flat light shielding film in a region where the second region is disposed. Production method. It is a manufacturing method of the solid-state image sensing device according to any one of claims 15 to 22,
A method for manufacturing a solid-state imaging device, comprising: forming an intra-layer lens above the first region and above the second region after forming the light shielding film. It is a manufacturing method of the solid-state image sensing device according to claim 23,
A method for producing a solid-state imaging device, wherein the in-layer lens is a downward convex lens. It is a manufacturing method of the solid-state image sensing device according to any one of claims 15 to 24, and
A method for manufacturing a solid-state imaging device, wherein the conductive member is formed of a light-shielding material. It is a manufacturing method of the solid-state image sensing device according to claim 25,
A method for manufacturing a solid-state imaging device, wherein the light-shielding material is metal or metal silicide. It is a manufacturing method of the solid-state image sensing device according to any one of claims 15 to 26, and
A method for manufacturing a solid-state imaging device, wherein the conductive member is formed of a polycrystalline silicon material.

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