WO2010032410A1 - Solid-state imaging device - Google Patents

Solid-state imaging device Download PDF

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Publication number
WO2010032410A1
WO2010032410A1 PCT/JP2009/004534 JP2009004534W WO2010032410A1 WO 2010032410 A1 WO2010032410 A1 WO 2010032410A1 JP 2009004534 W JP2009004534 W JP 2009004534W WO 2010032410 A1 WO2010032410 A1 WO 2010032410A1
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WO
WIPO (PCT)
Prior art keywords
transfer
wiring
transfer electrode
solid
state imaging
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PCT/JP2009/004534
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French (fr)
Japanese (ja)
Inventor
山本晃士
Ichiroh MURAKAMI (村上一朗)
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パナソニック株式会社
村上 正典
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Publication of WO2010032410A1 publication Critical patent/WO2010032410A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14603—Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14625—Optical elements or arrangements associated with the device
    • H01L27/14627—Microlenses
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/148—Charge coupled imagers
    • H01L27/14831—Area CCD imagers
    • H01L27/14843—Interline transfer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/148—Charge coupled imagers
    • H01L27/14868—CCD or CID colour imagers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/70—SSIS architectures; Circuits associated therewith
    • H04N25/76—Addressed sensors, e.g. MOS or CMOS sensors

Definitions

  • the present invention relates to a solid-state imaging device, and more particularly to a CCD (Charge Coupled Device) type solid-state imaging device.
  • CCD Charge Coupled Device
  • CCD-type solid-state imaging devices are required to have a large angle of view, pixel miniaturization, and high-speed driving.
  • the CCD type solid-state imaging device in order to read out the signal charge converted from light in the light receiving unit and transfer it to the output unit, it is necessary to periodically apply a potential as a transfer pulse to a transfer electrode arranged on the transfer channel. .
  • the transfer electrodes there are a structure having a multilayer structure in which a part of adjacent transfer electrodes are overlapped and a structure having a single layer structure in which adjacent transfer electrodes are not overlapped.
  • one pixel size has been miniaturized to 1.7 ⁇ m or less, and in order to reduce the height of the peripheral portion of the pixel and reduce the scatter of incident light. Layered ones are common.
  • the number of transfer electrodes per pixel was 3 or more.
  • a configuration in which two transfer electrodes per pixel, that is, one transfer electrode serving as both a transfer electrode and a readout electrode is provided. This is because with the miniaturization of pixels, the transfer electrodes are also required to be miniaturized, and it is necessary to increase the area of the transfer electrodes per pixel to ensure the amount of charge that can be accumulated per transfer electrode. is there.
  • the CCD type solid-state imaging device in order to read out and transfer signal charges, it is necessary to apply a driving pulse regularly to each row of transfer electrodes. Therefore, for example, it is common to form transfer electrodes connected in one direction, and to form a potential barrier in a semiconductor substrate under the connected transfer electrodes using a method such as ion implantation. This potential barrier serves to prevent the charge generated and accumulated in a certain light receiving portion from leaking to the light receiving portions of adjacent pixels.
  • the potential barrier formed under the transfer electrode formed in this manner is referred to as “channel stop”.
  • the electric field generated thereby modulates the channel stop through the interlayer insulating film, and the charge accumulated in the light receiving part may leak to the light receiving part of the adjacent pixel.
  • the channel stop is modulated and the barrier is lowered, there is a possibility that the photoelectrically converted charges diffuse in the channel stop region and leak to adjacent pixels. The leakage of charges to adjacent pixels causes so-called color mixing.
  • FIG. 10 shows the structure of the transfer electrode described in Patent Document 1.
  • the first transfer electrode 31A is formed by being connected in one direction as in the prior art.
  • the second transfer electrode 31B which also serves as a readout electrode, for reading out the electric charge accumulated in the light receiving unit 32 is separated from the other adjacent first transfer electrode 31A and the second transfer electrode 31B to form a floating island shape.
  • a wiring 33 is formed on the first transfer electrode 31A, and the wiring 33 and the second transfer electrode 31B are connected via a contact 34. .
  • the advantage of this method is that the layer of the first transfer electrode 31A exists between the wiring 33 for applying a drive pulse to the second transfer electrode 31B that also serves as the readout electrode and the substrate interface, and therefore the light is accumulated in the light receiving unit 32.
  • the influence of a relatively large drive pulse when reading the generated charge on the channel stop can be reduced, and the occurrence of color mixing can be reduced.
  • solid-state imaging devices will require a large number of pixels of 10 million pixels or more, and it is also required to realize high-speed driving that enables moving image shooting in addition to still image shooting. Therefore, it is necessary to miniaturize the channel stop. However, the finer the channel stop, the more difficult it is to design and form a potential barrier, and it becomes more difficult to suppress color mixing.
  • the transfer electrode formed on the channel stop is formed as the same layer as the transfer electrode formed on the transfer channel, the transfer electrode formed on the channel stop It is difficult to increase the thickness of the interlayer insulating film existing between the substrate interface. For this reason, it is difficult to sufficiently reduce the possibility that a driving pulse applied to the first transfer electrode when transferring charges modulates the channel stop and causes color mixing.
  • the present invention suppresses the occurrence of color mixing due to modulation of the channel stop portion by applying a potential to the transfer electrode, and maintains high performance such as sensitivity, smear, and saturation, and enables solid-state imaging that enables high-speed driving
  • An object is to provide an apparatus.
  • a solid-state imaging device is regularly arranged in the same direction between a plurality of light receiving portions formed regularly arranged on a semiconductor substrate and the light receiving portions on the semiconductor substrate. Formed in the same layer as the first transfer electrode on the transfer channel, the transfer channel formed on the transfer channel, and a plurality of first transfer electrodes disposed on the transfer channel. And a plurality of second transfer electrodes having a function of transferring the charge on the transfer channel and a function of a read electrode for reading the charge accumulated in the corresponding light receiving portion to the transfer channel. All of the first transfer electrode and the second transfer electrode are formed separately from the adjacent first transfer electrode or the second transfer electrode.
  • a plurality of first wirings for applying a driving pulse to the first transfer electrode via an interlayer insulating film and an upper portion of the first transfer electrode and the second transfer electrode, respectively, A plurality of second wirings for applying a driving pulse are provided.
  • the first transfer electrode and the first wiring are electrically connected via a first contact region, and the second transfer electrode and the second wiring are electrically connected via a second contact region. Has been.
  • all the first transfer electrodes and the second transfer electrodes are formed by separating the adjacent first transfer electrodes and the second transfer electrodes from each other.
  • the possibility that the channel stop portion under the formed transfer electrode is modulated and the barrier is lowered is eliminated.
  • an interlayer insulating film exists between the first wiring and the second wiring and the semiconductor substrate, a channel due to an electric field generated from the wiring is formed as compared with the case where only the gate insulating film exists on the transfer electrode. The influence on the stop portion can be reduced and color mixing can be suppressed.
  • FIG. 1 is a plan view showing a planar configuration of a solid-state imaging device according to an embodiment of the present invention.
  • FIG. 2 is a cross-sectional view showing a cross-sectional configuration along the line A-A ′ of FIG. 1.
  • FIG. 3 is a cross-sectional view showing a cross-sectional configuration taken along the line B-B 'of FIG.
  • FIG. 4 is a cross-sectional view showing a cross-sectional configuration taken along line C-C ′ of FIG.
  • FIG. 5 is a cross-sectional view showing a cross-sectional configuration taken along the line D-D 'of FIG.
  • FIG. 6 is a plan view showing a modification of the structure of the antireflection film in the solid-state imaging device of the embodiment shown in FIG. FIG.
  • FIG. 7 is a cross-sectional view showing a cross-sectional configuration taken along line E-E ′ of FIG. 6.
  • FIG. 8 is a plan view showing still another modified example of the structure of the antireflection film in the solid-state imaging device of the embodiment shown in FIG.
  • FIG. 9 is a cross-sectional view showing a cross-sectional configuration taken along the line F-F ′ of FIG. 8.
  • FIG. 10 is a plan view showing the structure of a transfer electrode in a conventional CCD solid-state imaging device.
  • the solid-state imaging device of the present invention can take the following aspects based on the above configuration.
  • the plurality of first wirings and the plurality of second wirings are formed in the same layer. Therefore, the distance from the surface of the solid-state imaging device to the light receiving unit can be suppressed to be small, which is advantageous for increasing the sensitivity of the solid-state imaging device.
  • At least one of the first wiring and the second wiring can be formed of polysilicon. Both the first wiring and the second wiring may be formed of polysilicon.
  • At least one of the first wiring and the second wiring is formed of a material having a resistivity lower than that of polysilicon. It is more preferable that both the first wiring and the second wiring are formed of a material having a resistivity lower than that of polysilicon.
  • Polysilicon is generally used as the wiring material, but in order to transfer charges at high speed, the voltage pulse is transferred to the transfer electrode by forming the wiring with a material having a lower resistivity than polysilicon. It is effective to prevent the delay and dullness of the pulse.
  • Examples of materials having a lower resistivity than polysilicon include tungsten, aluminum, copper, or metal silicide.
  • an antireflection film made of a material different from the interlayer insulating film is formed below the first wiring or the second wiring. Thereby, the distance between the wiring and the substrate interface can be further increased.
  • the material of the antireflection film a material having a dielectric constant different from that of the silicon oxide film can be mentioned.
  • the film may be formed of a silicon nitride film or a silicon oxynitride film that is generally used in a silicon process.
  • the first wiring extends so as to be commonly connected to the plurality of first transfer electrodes adjacent in one direction
  • the second wiring includes the plurality of second adjacent in one direction.
  • the antireflection film extends so as to be commonly connected to the transfer electrodes, and the antireflection film extends between the first transfer electrodes adjacent to each other in the same direction as the long axis of the first wiring and the length of the second wiring. It can be arranged between the second transfer electrodes adjacent in the same direction as the axis.
  • the antireflection film is formed on the entire surface of the light receiving portion and a part of at least one of the first transfer electrode and the second transfer electrode via the interlayer insulating film, and the first transfer. A part of the upper part of the electrode or a part of the upper part of the second transfer electrode may be removed.
  • a light shielding film is formed on the first transfer electrode and the second transfer electrode via the interlayer insulating film, the antireflection film, and a further interlayer insulating film. Can do.
  • the antireflection film may be formed so as to cover the upper part of the first transfer electrode, the upper part of the second transfer electrode, and the entire surface of the light receiving part. In that case, it is preferable that the antireflection film is removed in a part of the light receiving portion. This facilitates supplying hydrogen atoms for suppressing dark current into the silicon substrate.
  • FIG. 1 shows a planar configuration of a solid-state imaging device according to an embodiment of the present invention.
  • FIG. 2 shows a cross-sectional configuration taken along line AA ′ of FIG.
  • FIG. 3 shows a cross-sectional structure taken along line BB ′ of FIG.
  • FIG. 4 shows a cross-sectional configuration taken along the line CC ′ of FIG.
  • FIG. 5 shows a cross-sectional configuration along the line DD ′ in FIG.
  • illustration of some layers is omitted.
  • the solid-state imaging device of the present embodiment is configured by a four-phase drive CCD.
  • a plurality of light receiving portions 2 are formed in a matrix on a semiconductor substrate 1 (shown only in FIGS. 4 and 5).
  • the semiconductor substrate 1 is an n-type silicon substrate.
  • the light receiving unit 2 is a photodiode formed in a first p-type well 3 formed on the semiconductor substrate 1 and having a light receiving unit n-type region 2A and a light receiving unit p-type region 2B.
  • a plurality of transfer channels 4 (shown only in FIGS. 2, 4, and 5) extending in the first direction are formed in a region between the light receiving portions 2 in the semiconductor substrate 1.
  • the transfer channel 4 is an n-type region formed in the second p-type well 5 formed at a distance from the light receiving unit 2.
  • a first transfer electrode 6A and a second transfer electrode 6B that also serve as a readout electrode are formed at intervals. In the following description, when there is no need to distinguish the first transfer electrode 6A and the second transfer electrode 6B, they are referred to as transfer electrodes 6.
  • all the first transfer electrodes 6A and the second transfer electrodes 6B are formed separately from the other adjacent first transfer electrodes 6A and other second transfer electrodes 6B.
  • the first transfer electrode 6A and the second transfer electrode 6B are made of polysilicon or the like formed on the semiconductor substrate 1 with the gate insulating film 7 interposed therebetween.
  • the gate insulating film 7 is a gate insulating film for the transfer electrode 6.
  • the film thickness of the transfer electrode 6 may be about 100 nm.
  • a p-type channel stop portion 8 is formed around the light receiving portion 2 in the semiconductor substrate 1 except for a part thereof.
  • a gate portion 9 is formed.
  • the length of the second transfer electrode 6B along the transfer channel 4 is longer than that of the first transfer electrode 6A.
  • first wirings 11A for supplying drive pulses to the first transfer electrode 6A are formed via the first interlayer insulating film 10.
  • a plurality of second wirings 11B for supplying drive pulses to the second transfer electrode 6B are formed on the second transfer electrode 6B via the first interlayer insulating film 10.
  • the first wiring 11A is connected to the first transfer electrode 6A through a contact 12A
  • the second wiring 11B is connected to the second transfer electrode 6B through a contact 12B.
  • wirings 11 is made of, for example, polysilicon and has a film thickness of 150 nm.
  • an antireflection film 13 made of a material different from the interlayer insulating film is formed via the gate insulating film 7.
  • a first wiring 11A and a second wiring 11B are formed across the antireflection film 13 with the first interlayer insulating film 10 interposed therebetween.
  • the antireflection film 13 is made of, for example, a silicon nitride film, and has a film thickness of, for example, 50 nm.
  • the solid-state imaging device of the present embodiment has the following advantages due to the antireflection film 13 being disposed under the wiring 11. That is, since the gate insulating film 7, the antireflection film 13, and the first interlayer insulating film 10 exist between the first wiring 11 ⁇ / b> A and the second wiring 11 ⁇ / b> B on the channel stop portion 8 and the semiconductor substrate 1, the transfer electrode 6. Compared with the case where only the gate insulating film 7 exists as described above, the influence of the electric field generated from the wiring 11 on the channel stop portion 8 can be suppressed, and color mixing can be reduced.
  • the first transfer electrode 6A, the second transfer electrode 6B, the antireflection film 13, the first wiring 11A and the second wiring 11B are covered with the second interlayer insulating film 14.
  • a light shielding film 15 made of tungsten or the like is provided via the second interlayer insulating film 14 to the first transfer electrode 6A, the second transfer electrode 6B, the first wiring 11A, The second wiring 11 ⁇ / b> B and the antireflection film 13 are partly covered.
  • the third interlayer insulating film 16 may be formed of a BPSG (Borophosphosilicate glass) film or the like. Alternatively, the third interlayer insulating film 16 may be thinly formed, a material having a refractive index different from that of the third interlayer insulating film may be embedded, and the lens may be planarized to form a downward convex lens.
  • An intra-layer lens 17 made of, for example, a silicon oxide film or a silicon nitride film may be formed at a position corresponding to the light receiving unit 2 on the third interlayer insulating film 16.
  • the first flattening layer 18 made of a resin having a high transmittance for visible light is formed.
  • a color filter 19 for each color component of R (red), G (green), and B (blue) is formed in a region above the inner lens 17 in the first planarizing layer 18. The arrangement of each color is such that the R color component and the B color component are alternately filled between the G color components arranged in a checkered pattern.
  • the color filter 19 is not limited to this configuration, and may be a complementary color system, for example.
  • the color filter 19 is flattened by the second flattening layer 20, and an on-chip lens 21 is formed on the color filter 19.
  • signal charges are read from the predetermined light receiving unit 2 to the transfer channel 4.
  • a read pulse ⁇ VR is applied through the second wiring 11B to the second transfer electrode 6B corresponding to the light receiving unit 2 that performs reading.
  • the potential of the read pulse ⁇ VR may be 12V, for example.
  • the other second transfer electrode 6B is in a low level state.
  • the first transfer electrode 6A corresponding to the light receiving unit 2 that performs reading is set to the high level, and the other first transfer electrodes 6A are set to the low level.
  • the high level and the low level may be 0V and -6V, respectively.
  • the transfer channel 4 is in a state where the potential depth can receive the signal charge from the light receiving unit 2. Further, the potential of the read gate unit 9 changes, and the signal charge read operation from the light receiving unit 2 to the transfer channel 4 is performed.
  • transfer pulses ⁇ V1 to ⁇ V4 corresponding to four-phase driving are applied to the first transfer electrode 6A and the second transfer electrode 6B at a predetermined timing according to a known method.
  • the transfer pulses ⁇ V1 to ⁇ V4 may be set to ⁇ 6 V to 0 V, for example.
  • the signal charge read to the transfer channel 4 is transferred through the transfer channel 4. Further, the signal is transferred in the horizontal direction by a horizontal transfer unit (not shown), converted into a voltage corresponding to the signal charge amount by an output unit (not shown), and output.
  • the solid-state imaging device of the present embodiment configured as described above has the following characteristics. That is, all the first transfer electrodes 6A and the second transfer electrodes 6B are formed so as to separate the adjacent first transfer electrodes 6A and the second transfer electrodes 6B. Further, since the gate insulating film 7, the antireflection film 13, and the first interlayer insulating film 10 exist between the first wiring 11 ⁇ / b> A and the second wiring 11 ⁇ / b> B on the channel stop portion 8 and the semiconductor substrate 1, the transfer electrode 6, compared with the case where only the gate insulating film 7 exists, the influence of the electric field generated from the wiring 11 on the channel stop portion 8 can be reduced, and color mixing can be further suppressed.
  • Both the first wiring 11A and the second wiring 11B may be formed of a material having a specific resistance smaller than that of polysilicon.
  • Examples of a material having a specific resistance smaller than that of polysilicon include tungsten, aluminum, copper, metal silicide, and the like.
  • the wiring 11A and the second wiring 11B are formed of a material having a specific resistance smaller than that of polysilicon, the wiring can be made thinner than when the wiring is formed of polysilicon. Thereby, the ratio of the area occupied by the wiring per pixel can be reduced, and the ratio of the area occupied by the light receiving portion can be increased. Alternatively, it is possible to cope with pixel miniaturization that will further advance in the future. Further, the dullness and delay of the transfer pulse can be reduced as compared with the polysilicon wiring, which can contribute to high speed driving.
  • the resistivity of commonly used polysilicon wiring is about 7.5 ⁇ 10 ⁇ 4 ⁇ ⁇ m
  • the resistivity of tungsten is about 4.9 ⁇ 10 ⁇ 8 ⁇ ⁇ m.
  • a polysilicon wiring having a square with a side of 150 nm and a cross-sectional area of 2.25 ⁇ 10 ⁇ 2 square ⁇ m is formed as the wiring 11
  • a wiring having a resistance equivalent to this is formed with tungsten.
  • the cross sectional area may theoretically be 1.5 ⁇ 10 ⁇ 6 square ⁇ m.
  • metals such as tungsten, aluminum, and copper are used for the wiring
  • metal atoms may enter the semiconductor substrate through the gate insulating film due to etching or the like during wiring formation, which may cause deterioration in image quality. is there.
  • the antireflection film 13 is formed of a silicon nitride film or a silicon oxynitride film
  • the gate insulating film 7, the antireflection film 13, and the first interlayer insulating film 10 constitute an ONO film. Therefore, there is an advantage that the effect of preventing the metal atoms from entering the semiconductor substrate is higher than that in the case of the gate oxide film single layer.
  • the antireflection film 13 may be formed not only on the light receiving unit 2 but also on a part of the transfer electrode 6.
  • FIG. 6 shows a planar configuration of a solid-state imaging device having such a configuration.
  • FIG. 7 shows a cross-sectional structure taken along line E-E ′ of FIG.
  • the antireflection film 13a is formed via the first interlayer insulating film 10 so as to run over a part of the upper part of the first transfer electrode 6A and a part of the upper part of the second transfer electrode 6B. .
  • the antireflection film 13a covers the entire area of the light receiving unit 2, and the antireflection effect of incident light can be further enhanced.
  • the light shielding film 15 covers the first transfer electrode 6A, the second transfer electrode 6B, the first wiring 11A, and the second wiring 11B.
  • the interlayer insulating film 10, the antireflection film 13a, and the second interlayer insulating film 14 are formed.
  • hydrogen atoms are supplied to the semiconductor substrate 1 through the first interlayer insulating film 10 and the second interlayer insulating film 14, and silicon existing between the semiconductor substrate 1 and the gate insulating film 7 is present. Generation of dark current can be further suppressed because of bonding with a dangling bond of an atom.
  • the antireflection film 13 may be formed as shown in FIGS.
  • FIG. 8 shows a planar configuration of the solid-state imaging device
  • FIG. 9 shows a cross-sectional configuration taken along line F-F ′ of FIG.
  • the antireflection film 13b is formed on the entire surface of the light receiving unit 2, the first transfer electrode 6A, and the second transfer electrode 6B via the first interlayer insulating film 10.
  • the antireflection film 13b covers the entire light receiving part 2, and the antireflection effect of incident light can be further enhanced.
  • an opening 22 is formed in the antireflection film 13b on the light receiving portion 2.
  • the example in which the light receiving units 2 are arranged in a matrix is shown, but the light receiving units 2 may not be arranged in a matrix as long as they are regularly arranged.
  • the interline transfer type has been described as an example, the present invention can also be applied to a frame interline transfer transfer type solid-state imaging device.
  • the solid-state image pickup device can realize a solid-state image pickup device corresponding to high-speed driving by suppressing the occurrence of color mixing due to the modulation of the channel stop portion due to the potential application to the transfer electrode. This is useful as a solid-state imaging device.

Abstract

A solid-state imaging device is provided with a plurality of light-receiving portions (2), transfer channels which are regularly arranged in the same direction between the light-receiving portions, a plurality of first transfer electrodes (6A) which are disposed above the transfer channels, and a plurality of second transfer electrodes (6B) which are formed in the same layer as the first transfer electrodes and have a function of transferring electric charge on the transfer channels while being paired with the first transfer electrodes and a function of reading out electric charge stored in the light-receiving portions corresponding thereto to the transfer channels.  All of the first and second transfer electrodes are formed separately from the first or second transfer electrodes adjacent thereto.  A plurality of first and second lines (11A, 11B) for applying drive pulses, respectively, are provided above the first and second transfer electrodes with an interlayer insulating film interposed therebetween, and the first transfer electrodes and the second transfer electrodes are electrically connected with the first lines and the second lines, respectively, via contact regions (12A, 12B).  Consequently, the occurrence of color mixing caused by the modulation of a channel stop portion at the time when electric potential is applied to the transfer electrode is suppressed.

Description

固体撮像装置Solid-state imaging device
　本発明は、固体撮像装置に関し、特にＣＣＤ（Charge Coupled Device）型固体撮像装置に関する。 The present invention relates to a solid-state imaging device, and more particularly to a CCD (Charge Coupled Device) type solid-state imaging device.
　ＣＣＤ型固体撮像装置には、大画角化や画素の微細化、高速駆動化が求められている。ＣＣＤ型固体撮像装置では、受光部において光から変換された信号電荷を読み出し、出力部へ転送するため、転送チャネル上に配置された転送電極に転送パルスとして電位を周期的に印加する必要がある。 CCD-type solid-state imaging devices are required to have a large angle of view, pixel miniaturization, and high-speed driving. In the CCD type solid-state imaging device, in order to read out the signal charge converted from light in the light receiving unit and transfer it to the output unit, it is necessary to periodically apply a potential as a transfer pulse to a transfer electrode arranged on the transfer channel. .
　転送電極の配置としては、隣接する転送電極の一部を重ね合わせて配置した多層構造を有するものと、隣接する転送電極を重ね合わせずに配置した単層構造を有するものがある。近年は固体撮像素子の微細化に伴い、一つの画素サイズが１．７μｍ以下と微細化されてきており、画素周辺部の高さを低減し、入射光のけられを少なくするために、単層構造のものが一般的になっている。 As the arrangement of the transfer electrodes, there are a structure having a multilayer structure in which a part of adjacent transfer electrodes are overlapped and a structure having a single layer structure in which adjacent transfer electrodes are not overlapped. In recent years, with the miniaturization of solid-state imaging devices, one pixel size has been miniaturized to 1.7 μm or less, and in order to reduce the height of the peripheral portion of the pixel and reduce the scatter of incident light. Layered ones are common.
　一画素あたりの転送電極の数としては、かつては３個以上が主流であった。しかし最近は、一画素あたり２個の転送電極、すなわち、転送電極と読み出し電極を兼ねる転送電極とをそれぞれ１個ずつ設けた形態が一般的である。これは、画素の微細化に伴い転送電極も微細化が要求され、一画素当たりの転送電極の面積を大きくして、一つの転送電極当たりに蓄積できる電荷の量を確保する必要があるためである。 In the past, the number of transfer electrodes per pixel was 3 or more. However, recently, a configuration in which two transfer electrodes per pixel, that is, one transfer electrode serving as both a transfer electrode and a readout electrode is provided. This is because with the miniaturization of pixels, the transfer electrodes are also required to be miniaturized, and it is necessary to increase the area of the transfer electrodes per pixel to ensure the amount of charge that can be accumulated per transfer electrode. is there.
　ＣＣＤ型固体撮像装置では、信号電荷の読み出しや転送を行うために、転送電極の一列ごとに規則的に駆動パルスを印加する必要がある。そこで例えば、転送電極を一方向に連結して形成し、連結された転送電極下の半導体基板内には、イオン注入等の方法を用いてポテンシャル障壁を形成しておくのが一般的である。このポテンシャル障壁は、ある受光部に発生し蓄積された電荷が、隣接する画素の受光部へ漏れることを防ぐ役割を果たす。以後、この連結して形成された転送電極下に形成されるポテンシャル障壁を「チャネルストップ」と呼ぶ。 In the CCD type solid-state imaging device, in order to read out and transfer signal charges, it is necessary to apply a driving pulse regularly to each row of transfer electrodes. Therefore, for example, it is common to form transfer electrodes connected in one direction, and to form a potential barrier in a semiconductor substrate under the connected transfer electrodes using a method such as ion implantation. This potential barrier serves to prevent the charge generated and accumulated in a certain light receiving portion from leaking to the light receiving portions of adjacent pixels. Hereinafter, the potential barrier formed under the transfer electrode formed in this manner is referred to as “channel stop”.
　しかし、転送電極に駆動パルスを印加したとき、これにより生じる電界が層間絶縁膜を介してチャネルストップを変調し、受光部に蓄積された電荷が隣接する画素の受光部に漏れてしまう恐れがある。あるいは、チャネルストップが変調され障壁が下げられている際に、チャネルストップの領域において光電変換された電荷が拡散し隣接する画素に漏れてしまう恐れがある。隣接する画素への電荷の漏洩は、いわゆる混色を引き起こす。 However, when a drive pulse is applied to the transfer electrode, the electric field generated thereby modulates the channel stop through the interlayer insulating film, and the charge accumulated in the light receiving part may leak to the light receiving part of the adjacent pixel. . Alternatively, when the channel stop is modulated and the barrier is lowered, there is a possibility that the photoelectrically converted charges diffuse in the channel stop region and leak to adjacent pixels. The leakage of charges to adjacent pixels causes so-called color mixing.
　転送電極から発生する電界による、チャネルストップの変調を抑制する方法の一つとして、読み出し電極を兼ねる転送電極を、隣接する他の転送電極や読み出し兼用転送電極と分離して形成する技術が知られている。（例えば、特許文献１を参照）。 As one method for suppressing channel stop modulation due to an electric field generated from a transfer electrode, a technique is known in which a transfer electrode also serving as a readout electrode is formed separately from other adjacent transfer electrodes or readout / transfer electrodes. ing. (For example, see Patent Document 1).
　図１０に、特許文献１に記載された転送電極の構造を示す。この転送電極の構造を形成する方法ではまず、第１転送電極３１Ａを従来と同様に一方向に連結して形成する。次に、受光部３２で蓄積された電荷を読み出すための、読み出し電極を兼ねる第２転送電極３１Ｂを、隣接する他の第１転送電極３１Ａや第２転送電極３１Ｂと分離して、浮島状に形成する。続いて、第２転送電極３１Ｂに駆動パルスを印加できるようにするため、配線３３を第１転送電極３１Ａの上に形成し、配線３３と第２転送電極３１Ｂとをコンタクト３４を介して接続する。 FIG. 10 shows the structure of the transfer electrode described in Patent Document 1. In this method of forming the transfer electrode structure, first, the first transfer electrode 31A is formed by being connected in one direction as in the prior art. Next, the second transfer electrode 31B, which also serves as a readout electrode, for reading out the electric charge accumulated in the light receiving unit 32 is separated from the other adjacent first transfer electrode 31A and the second transfer electrode 31B to form a floating island shape. Form. Subsequently, in order to be able to apply a drive pulse to the second transfer electrode 31B, a wiring 33 is formed on the first transfer electrode 31A, and the wiring 33 and the second transfer electrode 31B are connected via a contact 34. .
　この方法の長所は、読み出し電極を兼ねる第２転送電極３１Ｂに駆動パルスを印加するための配線３３と基板界面との間に、第１転送電極３１Ａの層が存在するため、受光部３２に蓄積された電荷を読み出す時の比較的大きな駆動パルスがチャネルストップに及ぼす影響を小さくすることができ、混色の発生を低減できることである。 The advantage of this method is that the layer of the first transfer electrode 31A exists between the wiring 33 for applying a drive pulse to the second transfer electrode 31B that also serves as the readout electrode and the substrate interface, and therefore the light is accumulated in the light receiving unit 32. In other words, the influence of a relatively large drive pulse when reading the generated charge on the channel stop can be reduced, and the occurrence of color mixing can be reduced.
特開２００６－１４０４１１号公報JP 2006-140411 A
　固体撮像素子には今後、１０００万画素以上の大画素数が要望され、さらに静止画撮影に加えて動画撮影等を可能にする高速駆動も実現することが要求される。したがって、チャネルストップも微細化していく必要がある。しかし、チャネルストップを微細化すればするほど、ポテンシャル障壁の設計や形成が困難となり、混色を抑制することが難しくなっていく。 In the future, solid-state imaging devices will require a large number of pixels of 10 million pixels or more, and it is also required to realize high-speed driving that enables moving image shooting in addition to still image shooting. Therefore, it is necessary to miniaturize the channel stop. However, the finer the channel stop, the more difficult it is to design and form a potential barrier, and it becomes more difficult to suppress color mixing.
　また、上述の従来例の方式では、チャネルストップ上に形成される転送電極が、転送チャネル上に形成される転送電極と同じ層として形成されるために、チャネルストップ上に形成される転送電極と基板界面との間に存在する層間絶縁膜の膜厚を厚くすることが困難である。そのため、電荷を転送する際に第１転送電極に印加される駆動パルスがチャネルストップを変調させ、混色を発生させる恐れを十分に低くすることが困難である。 In the above-described conventional method, since the transfer electrode formed on the channel stop is formed as the same layer as the transfer electrode formed on the transfer channel, the transfer electrode formed on the channel stop It is difficult to increase the thickness of the interlayer insulating film existing between the substrate interface. For this reason, it is difficult to sufficiently reduce the possibility that a driving pulse applied to the first transfer electrode when transferring charges modulates the channel stop and causes color mixing.
　その上、一方が上部の配線からコンタクトを介して供給される駆動パルスであって、もう一方がチャネルストップ上にも形成されている転送電極から供給される駆動パルスである構成では、転送電極の材料の種類によってパルスの立ち上がり、立ち下りが異なる。このため、転送の設計を個別に行う必要が生じ、電荷転送の時間及び転送に必要な電界に関してマージンを持った設計を行うことを困難にしている。この結果、効率よく電荷の転送を行うためには転送チャネルの幅を広く取る必要が生じ、今後の微細化に対して障害になる。逆に、転送チャネルの幅を広く取れない場合には、転送に必要な電界の確保が困難となり、高速駆動が困難となる。 In addition, in the configuration in which one is a drive pulse supplied from the upper wiring through a contact and the other is a drive pulse supplied from the transfer electrode formed also on the channel stop, The rise and fall of the pulse differ depending on the type of material. For this reason, it is necessary to design the transfer individually, making it difficult to design with a margin regarding the charge transfer time and the electric field required for the transfer. As a result, in order to transfer charges efficiently, it is necessary to increase the width of the transfer channel, which hinders future miniaturization. Conversely, if the transfer channel cannot be wide, it is difficult to secure an electric field necessary for transfer, and high-speed driving becomes difficult.
　本発明は、転送電極への電位印加によりチャネルストップ部が変調を受けることに起因する混色の発生を抑制し、感度、スミア、飽和等の性能を維持しつつ、高速駆動を可能とした固体撮像装置を提供することを目的とする。 The present invention suppresses the occurrence of color mixing due to modulation of the channel stop portion by applying a potential to the transfer electrode, and maintains high performance such as sensitivity, smear, and saturation, and enables solid-state imaging that enables high-speed driving An object is to provide an apparatus.
　上記課題を解決するため、本発明の固体撮像装置は、半導体基板に規則的に配列して形成された複数の受光部と、前記半導体基板における前記受光部間に、同一方向に規則的に配列して形成された転送チャネルと、前記転送チャネル上に配置された複数の第１転送電極と、前記転送チャネル上における前記第１転送電極と同一の層に形成され、前記第１転送電極と対になり前記転送チャネル上の電荷を転送する機能、および対応する前記受光部に蓄積された電荷を前記転送チャネルに読み出す読み出し電極としての機能を有する複数の第２転送電極とを備える。前記第１転送電極及び前記第２転送電極の全てが、隣接する前記第１転送電極または前記第２転送電極と分離されて形成されている。前記第１転送電極の上部及び前記第２転送電極の上部にはそれぞれ、層間絶縁膜を介して、前記第１転送電極に駆動パルスを印加する複数の第１配線、及び前記第２転送電極に駆動パルスを印加する複数の第２配線が設けられている。前記第１転送電極と前記第１配線とは第１コンタクト領域を介して電気的に接続されており、前記第２転送電極と前記第２配線とは第２コンタクト領域を介して電気的に接続されている。 In order to solve the above-described problem, a solid-state imaging device according to the present invention is regularly arranged in the same direction between a plurality of light receiving portions formed regularly arranged on a semiconductor substrate and the light receiving portions on the semiconductor substrate. Formed in the same layer as the first transfer electrode on the transfer channel, the transfer channel formed on the transfer channel, and a plurality of first transfer electrodes disposed on the transfer channel. And a plurality of second transfer electrodes having a function of transferring the charge on the transfer channel and a function of a read electrode for reading the charge accumulated in the corresponding light receiving portion to the transfer channel. All of the first transfer electrode and the second transfer electrode are formed separately from the adjacent first transfer electrode or the second transfer electrode. A plurality of first wirings for applying a driving pulse to the first transfer electrode via an interlayer insulating film and an upper portion of the first transfer electrode and the second transfer electrode, respectively, A plurality of second wirings for applying a driving pulse are provided. The first transfer electrode and the first wiring are electrically connected via a first contact region, and the second transfer electrode and the second wiring are electrically connected via a second contact region. Has been.
　上記構成の固体撮像装置によれば、全ての第１転送電極及び第２転送電極は、隣接する第１転送電極及び第２転送電極との間を分離して形成されているので、連結して形成された転送電極下のチャネルストップ部が変調され障壁が下げられる恐れが解消する。また、第１配線及び第２配線と半導体基板との間には層間絶縁膜が存在するため、転送電極上のようにゲート絶縁膜のみが存在する場合に比べて、配線から発生する電界によるチャネルストップ部への影響を低減し、混色を抑制することができる。 According to the solid-state imaging device having the above configuration, all the first transfer electrodes and the second transfer electrodes are formed by separating the adjacent first transfer electrodes and the second transfer electrodes from each other. The possibility that the channel stop portion under the formed transfer electrode is modulated and the barrier is lowered is eliminated. In addition, since an interlayer insulating film exists between the first wiring and the second wiring and the semiconductor substrate, a channel due to an electric field generated from the wiring is formed as compared with the case where only the gate insulating film exists on the transfer electrode. The influence on the stop portion can be reduced and color mixing can be suppressed.
図１は、本発明の一実施形態における固体撮像装置の平面構成を示す平面図である。FIG. 1 is a plan view showing a planar configuration of a solid-state imaging device according to an embodiment of the present invention. 図２は、図１のＡ－Ａ’線における断面構成を示す断面図である。FIG. 2 is a cross-sectional view showing a cross-sectional configuration along the line A-A ′ of FIG. 1. 図３は、図１のＢ－Ｂ’線における断面構成を示す断面図である。FIG. 3 is a cross-sectional view showing a cross-sectional configuration taken along the line B-B 'of FIG. 図４は、図１のＣ－Ｃ’線における断面構成を示す断面図である。FIG. 4 is a cross-sectional view showing a cross-sectional configuration taken along line C-C ′ of FIG. 図５は、図１のＤ－Ｄ’線における断面構成を示す断面図である。FIG. 5 is a cross-sectional view showing a cross-sectional configuration taken along the line D-D 'of FIG. 図６は、図１に示した実施形態の固体撮像装置における反射防止膜の構造の変形例を示す平面図である。FIG. 6 is a plan view showing a modification of the structure of the antireflection film in the solid-state imaging device of the embodiment shown in FIG. 図７は、図６のＥ－Ｅ’線における断面構成を示す断面図である。FIG. 7 is a cross-sectional view showing a cross-sectional configuration taken along line E-E ′ of FIG. 6. 図８は、図１に示した実施形態の固体撮像装置における反射防止膜の構造の更に他の変形例を示す平面図である。FIG. 8 is a plan view showing still another modified example of the structure of the antireflection film in the solid-state imaging device of the embodiment shown in FIG. 図９は、図８のＦ－Ｆ’線における断面構成を示す断面図である。FIG. 9 is a cross-sectional view showing a cross-sectional configuration taken along the line F-F ′ of FIG. 8. 図１０は、従来例のＣＣＤ型固体撮像装置における転送電極の構造を示す平面図である。FIG. 10 is a plan view showing the structure of a transfer electrode in a conventional CCD solid-state imaging device.
　本発明の固体撮像装置は、上記構成を基本として以下のような態様をとることができる。 The solid-state imaging device of the present invention can take the following aspects based on the above configuration.
　すなわち、前記複数の第１配線と、前記複数の第２配線とが同一の層内に形成されていることが好ましい。それにより、固体撮像素子表面から受光部までの距離を小さく抑制することができ、固体撮像素子の感度を高めるために有利である。 That is, it is preferable that the plurality of first wirings and the plurality of second wirings are formed in the same layer. Thereby, the distance from the surface of the solid-state imaging device to the light receiving unit can be suppressed to be small, which is advantageous for increasing the sensitivity of the solid-state imaging device.
　また、前記第１配線及び前記第２配線の少なくとも一方は、ポリシリコンで形成することができる。前記第１配線及び前記第２配線の両方が、ポリシリコンで形成されていてもよい。 In addition, at least one of the first wiring and the second wiring can be formed of polysilicon. Both the first wiring and the second wiring may be formed of polysilicon.
　また、前記第１配線及び前記第２配線の少なくとも一方は、ポリシリコンよりも抵抗率が小さい材料で形成されていることが好ましい。前記第１配線及び前記第２配線の両方が、ポリシリコンよりも抵抗率が小さい材料で形成されていれば、より好ましい。配線の材料としては一般的にポリシリコンが用いられているが、電荷の転送を高速に行うためには、ポリシリコンよりも抵抗率が小さい材料で配線を形成することにより、電圧パルスを転送電極まで高速に伝達し、パルスの遅延や鈍りを防ぐことが効果的である。 Further, it is preferable that at least one of the first wiring and the second wiring is formed of a material having a resistivity lower than that of polysilicon. It is more preferable that both the first wiring and the second wiring are formed of a material having a resistivity lower than that of polysilicon. Polysilicon is generally used as the wiring material, but in order to transfer charges at high speed, the voltage pulse is transferred to the transfer electrode by forming the wiring with a material having a lower resistivity than polysilicon. It is effective to prevent the delay and dullness of the pulse.
　ポリシリコンよりも抵抗率が小さい材料の例としては、タングステン、アルミニウム、銅または金属シリサイドなどが挙げられる。 Examples of materials having a lower resistivity than polysilicon include tungsten, aluminum, copper, or metal silicide.
　また、前記第１配線または前記第２配線よりも下層に、層間絶縁膜とは異なる材料からなる反射防止膜が形成されることが好ましい。それにより、配線と基板界面との距離をより大きくすることができる。 Further, it is preferable that an antireflection film made of a material different from the interlayer insulating film is formed below the first wiring or the second wiring. Thereby, the distance between the wiring and the substrate interface can be further increased.
　反射防止膜の材料としては、シリコン酸化膜と異なる誘電率を有する材料が挙げられる。この一例として、シリコンプロセスに汎用的に用いられているシリコン窒化膜またはシリコン酸窒化膜で膜を形成してもよい。 As the material of the antireflection film, a material having a dielectric constant different from that of the silicon oxide film can be mentioned. As an example of this, the film may be formed of a silicon nitride film or a silicon oxynitride film that is generally used in a silicon process.
　また、前記第１配線は、一方向に隣接する複数の前記第１転送電極に対して共通に接続されるように延在し、前記第２配線は、一方向に隣接する複数の前記第２転送電極に対して共通に接続されるように延在し、前記反射防止膜は、前記第１配線の長軸と同一の方向に隣接する前記第１転送電極間、及び前記第２配線の長軸と同一の方向に隣接する前記第２転送電極間に配置することができる。 The first wiring extends so as to be commonly connected to the plurality of first transfer electrodes adjacent in one direction, and the second wiring includes the plurality of second adjacent in one direction. The antireflection film extends so as to be commonly connected to the transfer electrodes, and the antireflection film extends between the first transfer electrodes adjacent to each other in the same direction as the long axis of the first wiring and the length of the second wiring. It can be arranged between the second transfer electrodes adjacent in the same direction as the axis.
　また、前記反射防止膜は、前記受光部の全面と、前記第１転送電極および前記第２転送電極の少なくとも一方の上部の一部に、前記層間絶縁膜を介して形成され、前記第１転送電極の上部の一部または前記第２転送電極の上部の一部において取り除かれている構成とすることができる。 The antireflection film is formed on the entire surface of the light receiving portion and a part of at least one of the first transfer electrode and the second transfer electrode via the interlayer insulating film, and the first transfer. A part of the upper part of the electrode or a part of the upper part of the second transfer electrode may be removed.
　また、前記第１転送電極の上部及び前記第２転送電極の上部に、前記層間絶縁膜、前記反射防止膜、及び更なる層間絶縁膜を介して、遮光膜が形成されている構成とすることができる。 Further, a light shielding film is formed on the first transfer electrode and the second transfer electrode via the interlayer insulating film, the antireflection film, and a further interlayer insulating film. Can do.
　また、前記反射防止膜は、前記第１転送電極の上部、前記第２転送電極の上部、及び前記受光部の全面を覆うように、形成されている構成とすることができる。その場合、前記反射防止膜は、前記受光部の一部において取り除かれていることが好ましい。それにより、暗電流を抑制するための水素原子をシリコン基板内に供給することが容易となる。 The antireflection film may be formed so as to cover the upper part of the first transfer electrode, the upper part of the second transfer electrode, and the entire surface of the light receiving part. In that case, it is preferable that the antireflection film is removed in a part of the light receiving portion. This facilitates supplying hydrogen atoms for suppressing dark current into the silicon substrate.
　以下、本発明の実施形態について、図面を参照して説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　（実施形態）
　図１は、本発明の一実施形態における固体撮像装置の平面構成を示す。図２は、図１のＡ－Ａ’線における断面構成を示す。図３は、図１のＢ－Ｂ’線における断面構成を示す。図４は、図１のＣ－Ｃ’線における断面構成を示す。図５は、図１のＤ－Ｄ’線における断面構成を示す。但し、図２、図３では、一部の層の図示が省略されている。 (Embodiment)
FIG. 1 shows a planar configuration of a solid-state imaging device according to an embodiment of the present invention. FIG. 2 shows a cross-sectional configuration taken along line AA ′ of FIG. FIG. 3 shows a cross-sectional structure taken along line BB ′ of FIG. FIG. 4 shows a cross-sectional configuration taken along the line CC ′ of FIG. FIG. 5 shows a cross-sectional configuration along the line DD ′ in FIG. However, in FIG. 2 and FIG. 3, illustration of some layers is omitted.
　図１～５に示すように、本実施形態の固体撮像装置は、４相駆動ＣＣＤにより構成される。半導体基板１（図４、図５にのみ図示）に、複数の受光部２が行列状に形成されている。半導体基板１は、ｎ型シリコン基板である。受光部２は、半導体基板１の上部に形成された第１ｐ型ウェル３中に形成され、受光部ｎ型領域２Ａと受光部ｐ型領域２Ｂとを有するフォトダイオードである。 As shown in FIGS. 1 to 5, the solid-state imaging device of the present embodiment is configured by a four-phase drive CCD. A plurality of light receiving portions 2 are formed in a matrix on a semiconductor substrate 1 (shown only in FIGS. 4 and 5). The semiconductor substrate 1 is an n-type silicon substrate. The light receiving unit 2 is a photodiode formed in a first p-type well 3 formed on the semiconductor substrate 1 and having a light receiving unit n-type region 2A and a light receiving unit p-type region 2B.
　半導体基板１における受光部２同士の間の領域には、第１の方向に延びる複数の転送チャネル４（図２、図４、図５にのみ図示）が形成されている。転送チャネル４は、受光部２と間隔をおいて形成された第２ｐ型ウェル５中に形成されたｎ型領域である。転送チャネル４の上には、互いに間隔をおいて第１転送電極６Ａと、読み出し電極を兼ねる第２転送電極６Ｂが形成されている。なお、以下の記載において、第１転送電極６Ａと第２転送電極６Ｂを区別する必要がない場合は、転送電極６と記す。 A plurality of transfer channels 4 (shown only in FIGS. 2, 4, and 5) extending in the first direction are formed in a region between the light receiving portions 2 in the semiconductor substrate 1. The transfer channel 4 is an n-type region formed in the second p-type well 5 formed at a distance from the light receiving unit 2. On the transfer channel 4, a first transfer electrode 6A and a second transfer electrode 6B that also serve as a readout electrode are formed at intervals. In the following description, when there is no need to distinguish the first transfer electrode 6A and the second transfer electrode 6B, they are referred to as transfer electrodes 6.
　本実施形態においては、全ての第１転送電極６Ａ及び第２転送電極６Ｂは、隣接する他の第１転送電極６Ａ及び他の第２転送電極６Ｂとは分離されて形成されている。 In the present embodiment, all the first transfer electrodes 6A and the second transfer electrodes 6B are formed separately from the other adjacent first transfer electrodes 6A and other second transfer electrodes 6B.
　第１転送電極６Ａ及び第２転送電極６Ｂは、半導体基板１の上にゲート絶縁膜７を介して形成されたポリシリコン等からなる。ゲート絶縁膜７は、転送電極６に対するゲート絶縁膜である。転送電極６の膜厚は、１００ｎｍ程度とすればよい。 The first transfer electrode 6A and the second transfer electrode 6B are made of polysilicon or the like formed on the semiconductor substrate 1 with the gate insulating film 7 interposed therebetween. The gate insulating film 7 is a gate insulating film for the transfer electrode 6. The film thickness of the transfer electrode 6 may be about 100 nm.
　隣接する受光部２間での信号電荷の流出及び流入を防止するため、半導体基板１内における受光部２の周囲には、一部を除いてｐ型のチャネルストップ部８が形成されている。 In order to prevent outflow and inflow of signal charges between adjacent light receiving portions 2, a p-type channel stop portion 8 is formed around the light receiving portion 2 in the semiconductor substrate 1 except for a part thereof.
　受光部２と転送チャネル４との間におけるチャネルストップ部８が形成されていない領域（図４参照）は、第２転送電極６Ｂにより制御されて、受光部２に蓄積された信号電荷を読み出す読み出しゲート部９を形成する。 A region where the channel stop portion 8 is not formed between the light receiving portion 2 and the transfer channel 4 (see FIG. 4) is controlled by the second transfer electrode 6B to read out the signal charges accumulated in the light receiving portion 2. A gate portion 9 is formed.
　信号電荷の読み出しの観点からは、転送チャネル４に沿った第２転送電極６Ｂの長さを、第１転送電極６Ａよりも長くする方が好ましい。 From the viewpoint of reading the signal charge, it is preferable that the length of the second transfer electrode 6B along the transfer channel 4 is longer than that of the first transfer electrode 6A.
　第１転送電極６Ａの上には、第１層間絶縁膜１０を介して、第１転送電極６Ａに駆動パルスを供給する複数の第１配線１１Ａが形成されている。第２転送電極６Ｂの上には、第１層間絶縁膜１０を介して、第２転送電極６Ｂに駆動パルスを供給する複数の第２配線１１Ｂが形成されている。第１配線１１Ａは、コンタクト１２Ａにより第１転送電極６Ａと接続され、第２配線１１Ｂは、コンタクト１２Ｂにより第２転送電極６Ｂと接続されている。以後、第１配線１１Ａと第２配線１１Ｂを区別する必要がない場合は、配線１１と記す。配線１１は、例えばポリシリコンから形成されており、その膜厚は１５０ｎｍである。 On the first transfer electrode 6A, a plurality of first wirings 11A for supplying drive pulses to the first transfer electrode 6A are formed via the first interlayer insulating film 10. A plurality of second wirings 11B for supplying drive pulses to the second transfer electrode 6B are formed on the second transfer electrode 6B via the first interlayer insulating film 10. The first wiring 11A is connected to the first transfer electrode 6A through a contact 12A, and the second wiring 11B is connected to the second transfer electrode 6B through a contact 12B. Hereinafter, when it is not necessary to distinguish the first wiring 11A and the second wiring 11B, they are referred to as wirings 11. The wiring 11 is made of, for example, polysilicon and has a film thickness of 150 nm.
　転送電極６の間の受光部２上には、ゲート絶縁膜７を介して、層間絶縁膜とは異なる材料で形成された反射防止膜１３が形成されている。第１層間絶縁膜１０を介して反射防止膜１３上を横切り、第１配線１１Ａ及び第２配線１１Ｂが形成されている。反射防止膜１３は、例えばシリコン窒化膜からなり、その膜厚は例えば５０ｎｍである。 On the light receiving part 2 between the transfer electrodes 6, an antireflection film 13 made of a material different from the interlayer insulating film is formed via the gate insulating film 7. A first wiring 11A and a second wiring 11B are formed across the antireflection film 13 with the first interlayer insulating film 10 interposed therebetween. The antireflection film 13 is made of, for example, a silicon nitride film, and has a film thickness of, for example, 50 nm.
　このように、本実施形態の固体撮像装置では、配線１１の下に反射防止膜１３が配置されていることにより、次のような利点がある。すなわち、チャネルストップ部８上の第１配線１１Ａ及び第２配線１１Ｂと半導体基板１との間に、ゲート絶縁膜７、反射防止膜１３及び第１層間絶縁膜１０が存在するため、転送電極６上のようにゲート絶縁膜７のみが存在する場合に比べて、配線１１から発生する電界によるチャネルストップ部８への影響を抑制することができ、混色を低減することができる。 As described above, the solid-state imaging device of the present embodiment has the following advantages due to the antireflection film 13 being disposed under the wiring 11. That is, since the gate insulating film 7, the antireflection film 13, and the first interlayer insulating film 10 exist between the first wiring 11 </ b> A and the second wiring 11 </ b> B on the channel stop portion 8 and the semiconductor substrate 1, the transfer electrode 6. Compared with the case where only the gate insulating film 7 exists as described above, the influence of the electric field generated from the wiring 11 on the channel stop portion 8 can be suppressed, and color mixing can be reduced.
　第１転送電極６Ａ、第２転送電極６Ｂ、反射防止膜１３、第１配線１１Ａ及び第２配線１１Ｂは、第２層間絶縁膜１４に覆われている。 The first transfer electrode 6A, the second transfer electrode 6B, the antireflection film 13, the first wiring 11A and the second wiring 11B are covered with the second interlayer insulating film 14.
　転送チャネル４への光の入射を防止するために、タングステン等からなる遮光膜１５が、第２層間絶縁膜１４を介して、第１転送電極６Ａ、第２転送電極６Ｂ、第１配線１１Ａ、第２配線１１Ｂ、及び反射防止膜１３の一部を覆うように形成されている。 In order to prevent light from entering the transfer channel 4, a light shielding film 15 made of tungsten or the like is provided via the second interlayer insulating film 14 to the first transfer electrode 6A, the second transfer electrode 6B, the first wiring 11A, The second wiring 11 </ b> B and the antireflection film 13 are partly covered.
　図４、図５に示すように、遮光膜１５の上には、第１転送電極６Ａ、第２転送電極６Ｂ、第１配線１１Ａ及び第２配線１１Ｂにより形成された段差を平坦化する第３層間絶縁膜１６が形成されている。第３層間絶縁膜１６は、ＢＰＳＧ（Borophosphosilicate glass）膜等により形成すればよい。また、第３層間絶縁膜１６を薄く形成した上に第３層間絶縁膜とは異なる屈折率を有する材料を埋め込み、これを平坦化することにより下凸形状のレンズを形成してもよい。 As shown in FIGS. 4 and 5, on the light shielding film 15, a step formed by the first transfer electrode 6A, the second transfer electrode 6B, the first wiring 11A, and the second wiring 11B is flattened. An interlayer insulating film 16 is formed. The third interlayer insulating film 16 may be formed of a BPSG (Borophosphosilicate glass) film or the like. Alternatively, the third interlayer insulating film 16 may be thinly formed, a material having a refractive index different from that of the third interlayer insulating film may be embedded, and the lens may be planarized to form a downward convex lens.
　第３層間絶縁膜１６の上における受光部２に対応する位置には、例えばシリコン酸化膜またはシリコン窒化膜からなる層内レンズ１７を形成してもよい。この場合はレンズ間の谷間を平坦化するために、可視光に対して透過率の高い樹脂からなる第１平坦化層１８が形成される。第１平坦化層１８における層内レンズ１７の上側の領域には、Ｒ（赤）、Ｇ（緑）、Ｂ（青）の各色成分のカラーフィルタ１９が形成されている。各色の配置は、市松状に配置されたＧ色成分の間を、Ｒ色成分及びＢ色成分が交互に埋めるようになっている。カラーフィルタ１９はこの構成に限らず、例えば、補色系でもよい。カラーフィルタ１９は、第２平坦化層２０により平坦化され、カラーフィルタ１９の上にはオンチップレンズ２１が形成されている。 An intra-layer lens 17 made of, for example, a silicon oxide film or a silicon nitride film may be formed at a position corresponding to the light receiving unit 2 on the third interlayer insulating film 16. In this case, in order to flatten the valley between the lenses, the first flattening layer 18 made of a resin having a high transmittance for visible light is formed. A color filter 19 for each color component of R (red), G (green), and B (blue) is formed in a region above the inner lens 17 in the first planarizing layer 18. The arrangement of each color is such that the R color component and the B color component are alternately filled between the G color components arranged in a checkered pattern. The color filter 19 is not limited to this configuration, and may be a complementary color system, for example. The color filter 19 is flattened by the second flattening layer 20, and an on-chip lens 21 is formed on the color filter 19.
　以下に、本実施形態の固体撮像装置の駆動方法の一例を示す。まず、所定の受光部２から転送チャネル４へ信号電荷の読み出しを行う。読み出しを行う受光部２に対応する第２転送電極６Ｂに、第２配線１１Ｂを通して読み出しパルスφＶＲを印加する。読み出しパルスφＶＲの電位は、例えば１２Ｖとすればよい。このとき、他の第２転送電極６Ｂはローレベルの状態とする。また、読み出しを行う受光部２に対応する第１転送電極６Ａはハイレベルとし、他の第１転送電極６Ａはローレベルとする。ハイレベル及びローレベルは、それぞれ０Ｖ及び－６Ｖとすればよい。 Hereinafter, an example of a method for driving the solid-state imaging device according to the present embodiment will be described. First, signal charges are read from the predetermined light receiving unit 2 to the transfer channel 4. A read pulse φVR is applied through the second wiring 11B to the second transfer electrode 6B corresponding to the light receiving unit 2 that performs reading. The potential of the read pulse φVR may be 12V, for example. At this time, the other second transfer electrode 6B is in a low level state. Further, the first transfer electrode 6A corresponding to the light receiving unit 2 that performs reading is set to the high level, and the other first transfer electrodes 6A are set to the low level. The high level and the low level may be 0V and -6V, respectively.
　これにより、転送チャネル４はそのポテンシャル深さが、受光部２から信号電荷を受け取ることのできる状態になる。また、読み出しゲート部９のポテンシャルが変化し、受光部２から転送チャネル４への信号電荷の読み出し動作が行われる。 Thus, the transfer channel 4 is in a state where the potential depth can receive the signal charge from the light receiving unit 2. Further, the potential of the read gate unit 9 changes, and the signal charge read operation from the light receiving unit 2 to the transfer channel 4 is performed.
　次に、第１転送電極６Ａ及び第２転送電極６Ｂに対して、周知の方法に従い、４相駆動に対応した転送パルスφＶ１～φＶ４を所定のタイミングで印加する。転送パルスφＶ１～φＶ４は、例えば－６Ｖ～０Ｖとすればよい。これにより、転送チャネル４に読み出された信号電荷は、転送チャネル４中を転送される。さらに、水平転送部（図示せず）により水平方向に転送され、出力部（図示せず）により信号電荷量に応じた電圧に変換されて出力される。 Next, transfer pulses φV1 to φV4 corresponding to four-phase driving are applied to the first transfer electrode 6A and the second transfer electrode 6B at a predetermined timing according to a known method. The transfer pulses φV1 to φV4 may be set to −6 V to 0 V, for example. As a result, the signal charge read to the transfer channel 4 is transferred through the transfer channel 4. Further, the signal is transferred in the horizontal direction by a horizontal transfer unit (not shown), converted into a voltage corresponding to the signal charge amount by an output unit (not shown), and output.
　以上のように構成された本実施形態の固体撮像装置は、以下のような特徴を有する。すなわち、全ての第１転送電極６Ａ及び第２転送電極６Ｂは、隣接する第１転送電極６Ａ及び第２転送電極６Ｂとの間を分離して形成されている。また、チャネルストップ部８上の第１配線１１Ａ及び第２配線１１Ｂと半導体基板１との間には、ゲート絶縁膜７、反射防止膜１３及び第１層間絶縁膜１０が存在するため、転送電極６上のようにゲート絶縁膜７のみが存在する場合に比べて、配線１１から発生する電界によるチャネルストップ部８への影響を低減し、混色をより抑制することができる。 The solid-state imaging device of the present embodiment configured as described above has the following characteristics. That is, all the first transfer electrodes 6A and the second transfer electrodes 6B are formed so as to separate the adjacent first transfer electrodes 6A and the second transfer electrodes 6B. Further, since the gate insulating film 7, the antireflection film 13, and the first interlayer insulating film 10 exist between the first wiring 11 </ b> A and the second wiring 11 </ b> B on the channel stop portion 8 and the semiconductor substrate 1, the transfer electrode 6, compared with the case where only the gate insulating film 7 exists, the influence of the electric field generated from the wiring 11 on the channel stop portion 8 can be reduced, and color mixing can be further suppressed.
　第１配線１１Ａ及び第２配線１１Ｂを、共にポリシリコンよりも比抵抗の小さな材料で形成してもよい。ポリシリコンよりも比抵抗が小さな材料の一例としては、タングステン、アルミニウム、銅、金属シリサイドなどが挙げられる。 Both the first wiring 11A and the second wiring 11B may be formed of a material having a specific resistance smaller than that of polysilicon. Examples of a material having a specific resistance smaller than that of polysilicon include tungsten, aluminum, copper, metal silicide, and the like.
　第１配線１１Ａ及び第２配線１１Ｂをポリシリコンよりも比抵抗が小さい材料で形成した場合は、配線をポリシリコンで形成した場合に比べて配線を細くすることができる。これにより、一画素あたりに配線が占める面積の割合を小さくし、受光部の占める面積の割合を大きくすることができる。あるいは、今後さらに進展する画素の微細化にも対応することができる。また、ポリシリコン配線に比べて転送パルスの鈍りや遅延を小さくすることができ、高速駆動化にも寄与できる。 When the first wiring 11A and the second wiring 11B are formed of a material having a specific resistance smaller than that of polysilicon, the wiring can be made thinner than when the wiring is formed of polysilicon. Thereby, the ratio of the area occupied by the wiring per pixel can be reduced, and the ratio of the area occupied by the light receiving portion can be increased. Alternatively, it is possible to cope with pixel miniaturization that will further advance in the future. Further, the dullness and delay of the transfer pulse can be reduced as compared with the polysilicon wiring, which can contribute to high speed driving.
　例えば、一般に用いられているポリシリコン配線の抵抗率は７．５×１０－４Ω・ｍ程度であり、タングステンの抵抗率は４．９×１０－８Ω・ｍ程度である。ここで配線１１として、一辺が１５０ｎｍの正方形で断面積が２．２５×１０－２平方μｍのポリシリコン配線を形成した場合に、これと同等の抵抗を有する配線をタングステンで形成した場合には、断面積は理論上１．５×１０－６平方μｍでよい。 For example, the resistivity of commonly used polysilicon wiring is about 7.5 × 10 −4 Ω · m, and the resistivity of tungsten is about 4.9 × 10 −8 Ω · m. Here, in the case where a polysilicon wiring having a square with a side of 150 nm and a cross-sectional area of 2.25 × 10 −2 square μm is formed as the wiring 11, a wiring having a resistance equivalent to this is formed with tungsten. The cross sectional area may theoretically be 1.5 × 10 −6 square μm.
　また、タングステン、アルミニウム、銅をはじめとする金属を配線に用いた場合には、配線形成時のエッチング等により金属原子がゲート絶縁膜を通じて半導体基板内部に進入し、画質劣化の原因となる恐れがある。本実施形態において、反射防止膜１３をシリコン窒化膜あるいはシリコン酸窒化膜で形成する場合には、ゲート絶縁膜７、反射防止膜１３及び第１層間絶縁膜１０によりＯＮＯ膜を構成することになるため、ゲート酸化膜単層の場合よりも金属原子の半導体基板への侵入防止効果が高くなる利点がある。 In addition, when metals such as tungsten, aluminum, and copper are used for the wiring, metal atoms may enter the semiconductor substrate through the gate insulating film due to etching or the like during wiring formation, which may cause deterioration in image quality. is there. In the present embodiment, when the antireflection film 13 is formed of a silicon nitride film or a silicon oxynitride film, the gate insulating film 7, the antireflection film 13, and the first interlayer insulating film 10 constitute an ONO film. Therefore, there is an advantage that the effect of preventing the metal atoms from entering the semiconductor substrate is higher than that in the case of the gate oxide film single layer.
　反射防止膜１３は、図６、図７に示すように、受光部２上のみならず転送電極６上の一部に乗り上げるように形成してもよい。図６は、そのような構成を有する固体撮像装置の平面構成を示す。図７は、図６のＥ－Ｅ’線における断面構成を示す。図６では、反射防止膜１３ａが、第１転送電極６Ａの上部の一部、及び第２転送電極６Ｂの上部の一部に乗り上げるように、第１層間絶縁膜１０を介して形成されている。これにより、反射防止膜１３ａは受光部２の全域を覆うことになり、入射光の反射防止効果をさらに高めることができる。 As shown in FIGS. 6 and 7, the antireflection film 13 may be formed not only on the light receiving unit 2 but also on a part of the transfer electrode 6. FIG. 6 shows a planar configuration of a solid-state imaging device having such a configuration. FIG. 7 shows a cross-sectional structure taken along line E-E ′ of FIG. In FIG. 6, the antireflection film 13a is formed via the first interlayer insulating film 10 so as to run over a part of the upper part of the first transfer electrode 6A and a part of the upper part of the second transfer electrode 6B. . Thereby, the antireflection film 13a covers the entire area of the light receiving unit 2, and the antireflection effect of incident light can be further enhanced.
　また図７に示すように、遮光膜１５が、第１転送電極６Ａの上部、第２転送電極６Ｂの上部、第１配線１１Ａの上部、及び第２配線１１Ｂの上部を覆うように、第１層間絶縁膜１０、及び反射防止膜１３ａ、及び第２層間絶縁膜１４を介して形成されている。これにより、水素アニールを行った場合に、水素原子が第１層間絶縁膜１０、第２層間絶縁膜１４を通じて半導体基板１に供給され、半導体基板１とゲート絶縁膜７との間に存在するシリコン原子の非結合手と結合するため、暗電流の発生をさらに抑制することができる。 Further, as shown in FIG. 7, the light shielding film 15 covers the first transfer electrode 6A, the second transfer electrode 6B, the first wiring 11A, and the second wiring 11B. The interlayer insulating film 10, the antireflection film 13a, and the second interlayer insulating film 14 are formed. Thus, when hydrogen annealing is performed, hydrogen atoms are supplied to the semiconductor substrate 1 through the first interlayer insulating film 10 and the second interlayer insulating film 14, and silicon existing between the semiconductor substrate 1 and the gate insulating film 7 is present. Generation of dark current can be further suppressed because of bonding with a dangling bond of an atom.
　あるいは、反射防止膜１３を図８、図９に示すように形成してもよい。図８は固体撮像装置の平面構成を示し、図９は、図８のＦ－Ｆ’線における断面構成を示す。この構成では、反射防止膜１３ｂが、受光部２、第１転送電極６Ａの上部及び第２転送電極６Ｂの上部の全面に第１層間絶縁膜１０を介して形成されている。これにより、反射防止膜１３ｂは受光部２の全体を覆うことになり、入射光の反射防止効果をさらに高めることができる。 Alternatively, the antireflection film 13 may be formed as shown in FIGS. FIG. 8 shows a planar configuration of the solid-state imaging device, and FIG. 9 shows a cross-sectional configuration taken along line F-F ′ of FIG. In this configuration, the antireflection film 13b is formed on the entire surface of the light receiving unit 2, the first transfer electrode 6A, and the second transfer electrode 6B via the first interlayer insulating film 10. Thereby, the antireflection film 13b covers the entire light receiving part 2, and the antireflection effect of incident light can be further enhanced.
　また、受光部２上の反射防止膜１３ｂに開口部２２が形成されていることが好ましい。これにより、水素アニールを行った場合に、水素原子が開口部２２を通じて半導体基板１に供給され、半導体基板１とゲート絶縁膜７との間に存在するシリコン原子の非結合手と結合するため、暗電流の発生をさらに抑制することができる。 Further, it is preferable that an opening 22 is formed in the antireflection film 13b on the light receiving portion 2. As a result, when hydrogen annealing is performed, hydrogen atoms are supplied to the semiconductor substrate 1 through the opening 22 and are combined with the dangling bonds of silicon atoms existing between the semiconductor substrate 1 and the gate insulating film 7. Generation of dark current can be further suppressed.
　以上の実施形態及び変形例においては、受光部２が行列状に配置された例を示したが、受光部２は規則的に配置されていれば、行列状に配置されていなくてもよい。また、インターライン転送型を例として説明したが、本発明は、フレームインターライントランスファ転送型の固体撮像装置にも適用することができる。 In the above embodiment and modification, the example in which the light receiving units 2 are arranged in a matrix is shown, but the light receiving units 2 may not be arranged in a matrix as long as they are regularly arranged. Although the interline transfer type has been described as an example, the present invention can also be applied to a frame interline transfer transfer type solid-state imaging device.
　本発明に係る固体撮像装置は、転送電極への電位印加によりチャネルストップ部が変調を受けることに起因する混色の発生を抑制して、高速な駆動に対応した固体撮像装置を実現でき、特にＣＣＤ型の固体撮像装置等として有用である。 The solid-state image pickup device according to the present invention can realize a solid-state image pickup device corresponding to high-speed driving by suppressing the occurrence of color mixing due to the modulation of the channel stop portion due to the potential application to the transfer electrode. This is useful as a solid-state imaging device.
１　半導体基板
２、３２　受光部
２Ａ　受光部ｎ型領域
２Ｂ　受光部ｐ型領域
３　第１ｐ型ウェル
４　転送チャネル
５　第２ｐ型ウェル
６Ａ、３１Ａ　第１転送電極
６Ｂ、３１Ｂ　第２転送電極（読み出し電極を兼ねる転送電極）
７　ゲート絶縁膜
８　チャネルストップ部
９　読み出しゲート部
１０　第１層間絶縁膜
１１、３３　配線
１１Ａ　第１配線
１１Ｂ　第２配線
１２Ａ、１２Ｂ、３４　コンタクト
１３、１３ａ、１３ｂ　反射防止膜
１４　第２層間絶縁膜
１５　遮光膜
１６　第３層間絶縁膜
１７　層内レンズ
１８　第１平坦化層
１９　カラーフィルタ
２０　第２平坦化層
２１　オンチップレンズ
２２　開口部 DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 2, 32 Light-receiving part 2A Light-receiving part n-type area | region 2B Light-receiving part p-type area | region 3 1st p-type well 4 Transfer channel 5 2nd p- type well 6A, 31A 1st transfer electrode 6B, 31B 2nd transfer electrode (read-out electrode) Transfer electrode)
7 Gate insulating film 8 Channel stop portion 9 Read gate portion 10 First interlayer insulating film 11, 33 Wiring 11A First wiring 11B Second wiring 12A, 12B, 34 Contacts 13, 13a, 13b Antireflection film 14 Second interlayer insulating film 15 light shielding film 16 third interlayer insulating film 17 inner lens 18 first planarizing layer 19 color filter 20 second planarizing layer 21 on-chip lens 22 opening

Claims (15)

  1. 　半導体基板に規則的に配列して形成された複数の受光部と、
    　前記半導体基板における前記受光部間に、同一方向に規則的に配列して形成された転送チャネルと、
    　前記転送チャネル上に配置された複数の第１転送電極と、
    　前記転送チャネル上における前記第１転送電極と同一の層に形成され、前記第１転送電極と対になり前記転送チャネル上の電荷を転送する機能、および対応する前記受光部に蓄積された電荷を前記転送チャネルに読み出す読み出し電極としての機能を有する複数の第２転送電極とを備え、
    　前記第１転送電極及び前記第２転送電極の全てが、隣接する前記第１転送電極または前記第２転送電極と分離されて形成されており、
    　前記第１転送電極の上部及び前記第２転送電極の上部にはそれぞれ、層間絶縁膜を介して、前記第１転送電極に駆動パルスを印加する複数の第１配線、及び前記第２転送電極に駆動パルスを印加する複数の第２配線が設けられ、
    　前記第１転送電極と前記第１配線とは第１コンタクト領域を介して電気的に接続されており、
    　前記第２転送電極と前記第２配線とは第２コンタクト領域を介して電気的に接続されていることを特徴とする固体撮像装置。     A plurality of light receiving portions formed regularly arranged on a semiconductor substrate;
    A transfer channel formed regularly in the same direction between the light receiving portions in the semiconductor substrate,
    A plurality of first transfer electrodes disposed on the transfer channel;
    A function of transferring charge on the transfer channel formed in the same layer as the first transfer electrode on the transfer channel and paired with the first transfer electrode, and charge stored in the corresponding light receiving unit. A plurality of second transfer electrodes having a function as a read electrode for reading out to the transfer channel;
    All of the first transfer electrode and the second transfer electrode are formed separately from the adjacent first transfer electrode or the second transfer electrode,
    A plurality of first wirings for applying a drive pulse to the first transfer electrode via an interlayer insulating film and an upper part of the first transfer electrode and the second transfer electrode, respectively, A plurality of second wirings for applying a driving pulse are provided,
    The first transfer electrode and the first wiring are electrically connected via a first contact region,
    The solid-state imaging device, wherein the second transfer electrode and the second wiring are electrically connected via a second contact region.
  2. 　前記複数の第１配線と、前記複数の第２配線とが同一の層内に形成されている請求項１に記載の固体撮像装置。 The solid-state imaging device according to claim 1, wherein the plurality of first wirings and the plurality of second wirings are formed in the same layer.
  3. 　前記第１配線及び前記第２配線の少なくとも一方は、ポリシリコンで形成されている請求項１に記載の固体撮像装置。 2. The solid-state imaging device according to claim 1, wherein at least one of the first wiring and the second wiring is made of polysilicon.
  4. 　前記第１配線及び前記第２配線の両方が、ポリシリコンで形成されている請求項３に記載の固体撮像装置。 4. The solid-state imaging device according to claim 3, wherein both the first wiring and the second wiring are formed of polysilicon.
  5. 　前記第１配線及び前記第２配線の少なくとも一方は、ポリシリコンよりも抵抗率が小さい材料で形成されている請求項１に記載の固体撮像装置。 2. The solid-state imaging device according to claim 1, wherein at least one of the first wiring and the second wiring is formed of a material having a resistivity lower than that of polysilicon.
  6. 　前記第１配線及び前記第２配線の両方が、ポリシリコンよりも抵抗率が小さい材料で形成されている請求項５に記載の固体撮像装置。 6. The solid-state imaging device according to claim 5, wherein both the first wiring and the second wiring are formed of a material having a resistivity lower than that of polysilicon.
  7. 　前記ポリシリコンよりも抵抗率が小さい材料は、タングステン、アルミニウム、銅または金属シリサイドである請求項５に記載の固体撮像装置。 6. The solid-state imaging device according to claim 5, wherein the material having a resistivity lower than that of polysilicon is tungsten, aluminum, copper, or metal silicide.
  8. 　前記第１配線または前記第２配線よりも下層に、層間絶縁膜とは異なる材料からなる反射防止膜が形成されている請求項１に記載の固体撮像装置。 The solid-state imaging device according to claim 1, wherein an antireflection film made of a material different from the interlayer insulating film is formed below the first wiring or the second wiring.
  9. 　前記反射防止膜は、シリコン酸化膜と誘電率の異なる材料で形成されている請求項８に記載の固体撮像装置。 The solid-state imaging device according to claim 8, wherein the antireflection film is formed of a material having a dielectric constant different from that of the silicon oxide film.
  10. 　前記反射防止膜は、シリコン窒化膜またはシリコン酸窒化膜で形成されている請求項８に記載の固体撮像装置。 The solid-state imaging device according to claim 8, wherein the antireflection film is formed of a silicon nitride film or a silicon oxynitride film.
  11. 　前記第１配線は、一方向に隣接する複数の前記第１転送電極に対して共通に接続されるように延在し、
    　前記第２配線は、一方向に隣接する複数の前記第２転送電極に対して共通に接続されるように延在し、
    　前記反射防止膜は、前記第１配線の長軸と同一の方向に隣接する前記第１転送電極間、及び前記第２配線の長軸と同一の方向に隣接する前記第２転送電極間に配置されている請求項８に記載の固体撮像装置。     The first wiring extends so as to be commonly connected to the plurality of first transfer electrodes adjacent in one direction,
    The second wiring extends so as to be commonly connected to the plurality of second transfer electrodes adjacent in one direction,
    The antireflection film is disposed between the first transfer electrodes adjacent in the same direction as the long axis of the first wiring and between the second transfer electrodes adjacent in the same direction as the long axis of the second wiring. The solid-state imaging device according to claim 8.
  12. 　前記反射防止膜は、前記受光部の全面と、前記第１転送電極および前記第２転送電極の少なくとも一方の上部の一部に、前記層間絶縁膜を介して形成され、前記第１転送電極の上部の一部または前記第２転送電極の上部の一部において取り除かれている請求項８に記載の固体撮像装置。 The antireflection film is formed on the entire surface of the light receiving portion and a part of at least one of the first transfer electrode and the second transfer electrode with the interlayer insulating film interposed therebetween. The solid-state imaging device according to claim 8, wherein the solid-state imaging device is removed at a part of the upper part or a part of the upper part of the second transfer electrode.
  13. 　前記第１転送電極の上部及び前記第２転送電極の上部に、前記層間絶縁膜、前記反射防止膜、及び更なる層間絶縁膜を介して、遮光膜が形成されている請求項１２に記載の固体撮像装置。 The light-shielding film is formed on the upper part of the first transfer electrode and the upper part of the second transfer electrode via the interlayer insulating film, the antireflection film, and a further interlayer insulating film. Solid-state imaging device.
  14. 　前記反射防止膜は、前記第１転送電極の上部、前記第２転送電極の上部、及び前記受光部の全面を覆うように、形成されている請求項８に記載の固体撮像装置。 The solid-state imaging device according to claim 8, wherein the antireflection film is formed so as to cover an upper portion of the first transfer electrode, an upper portion of the second transfer electrode, and an entire surface of the light receiving portion.
  15. 　前記反射防止膜は、前記受光部の一部において取り除かれている請求項１４に記載の固体撮像装置。 The solid-state imaging device according to claim 14, wherein the antireflection film is removed in a part of the light receiving unit.
PCT/JP2009/004534 2008-09-22 2009-09-11 Solid-state imaging device WO2010032410A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62208668A (en) * 1986-03-10 1987-09-12 Hitachi Ltd Charge transfer type solid-state image sensing element
JPH07176714A (en) * 1993-12-20 1995-07-14 Nec Corp Manufacture of semiconductor device
JPH1065130A (en) * 1996-06-26 1998-03-06 Lg Semicon Co Ltd Solid-state image pickup device and manufacture thereof
JP2006041369A (en) * 2004-07-29 2006-02-09 Sony Corp Solid-state image pickup device, and manufacturing method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62208668A (en) * 1986-03-10 1987-09-12 Hitachi Ltd Charge transfer type solid-state image sensing element
JPH07176714A (en) * 1993-12-20 1995-07-14 Nec Corp Manufacture of semiconductor device
JPH1065130A (en) * 1996-06-26 1998-03-06 Lg Semicon Co Ltd Solid-state image pickup device and manufacture thereof
JP2006041369A (en) * 2004-07-29 2006-02-09 Sony Corp Solid-state image pickup device, and manufacturing method thereof

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