WO2012081139A1 - Solid-state image pickup device - Google Patents

Solid-state image pickup device Download PDF

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Publication number
WO2012081139A1
WO2012081139A1 PCT/JP2011/004107 JP2011004107W WO2012081139A1 WO 2012081139 A1 WO2012081139 A1 WO 2012081139A1 JP 2011004107 W JP2011004107 W JP 2011004107W WO 2012081139 A1 WO2012081139 A1 WO 2012081139A1
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Prior art keywords
transfer
photoelectric conversion
solid
adjacent
region
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PCT/JP2011/004107
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French (fr)
Japanese (ja)
Inventor
郁夫 水野
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パナソニック株式会社
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Publication of WO2012081139A1 publication Critical patent/WO2012081139A1/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
    • H01L27/148—Charge coupled imagers
    • H01L27/14806—Structural or functional details thereof
    • H01L27/14812—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
    • H01L27/148—Charge coupled imagers
    • H01L27/14831—Area CCD imagers

Definitions

  • the present invention relates to a solid-state imaging device, and more particularly to a 1-pixel 1-electrode type CCD (Charge Coupled Device) type solid-state imaging device.
  • CCD Charge Coupled Device
  • Solid-state imaging devices typified by CCD image sensors are widely used in digital still cameras, digital video cameras, and the like, and their demand is increasing. With the recent demand for a large number of pixels and a reduction in size of a solid-state imaging device, the pixels are arranged with high density and the pixel size tends to be reduced.
  • Patent Document 1 a technique for increasing the amount of signal charges handled in the transfer channel while reducing the width of the transfer channel is disclosed.
  • FIG. 12 is a diagram schematically showing the arrangement relationship of the components related to the solid-state imaging device described in Patent Document 1.
  • the solid-state imaging device described in Patent Document 1 includes a plurality of photodiodes (photoelectric conversion units) 902 for converting incident light into signal charges in the XY plane direction in the semiconductor substrate. Arranged in a matrix. A plurality of photodiodes 902 are arranged in the Y direction (column direction) to form a column of photodiodes 902, and signal charges corresponding to one column of photodiodes are transferred between adjacent photodiode columns. For this purpose, a vertical CCD (transfer channel) 903 is formed.
  • photodiodes photoelectric conversion units
  • a transfer electrode 904 that reads the signal charge from the corresponding photodiode 902 in a one-to-one correspondence with the photodiode 902 and transfers the signal in the vertical CCD 903 from the upstream side to the downstream side in the transfer direction. Is formed.
  • the transfer electrodes 904 adjacent in the X direction are connected to each other by a connection portion 905.
  • an element isolation region is provided in a region in the semiconductor substrate corresponding to the connection portion 905. Is formed.
  • Patent Document 1 is a so-called one-pixel one-electrode type in which one transfer electrode 904 is arranged for one photodiode 902. Therefore, for example, the amount of signal charges handled by the vertical CCD 903 can be doubled as compared with a case where two transfer electrodes are arranged for one photodiode (a so-called one-pixel two-electrode type).
  • an object of the present invention is to provide a solid-state imaging device having a charge transfer rate that can withstand an increase in transfer frequency.
  • a solid-state imaging device is formed in a matrix in a semiconductor substrate, and is adjacent to a plurality of photoelectric conversion units that convert incident light into signal charges, in the semiconductor substrate.
  • a plurality of transfer channels formed between columns of photoelectric conversion units and a region corresponding to the transfer channel on the semiconductor substrate are formed in the column direction in a one-to-one correspondence with the photoelectric conversion units.
  • a transfer electrode that reads the signal charge from the photoelectric conversion unit and transfers the signal in the transfer channel from the upstream side to the downstream side in the transfer direction, and is adjacent in the column direction when the plurality of transfer electrodes are viewed in plan view
  • the upstream end of the transfer electrode is formed to be inclined with respect to the row direction, and the downstream side of the transfer electrode adjacent to the upstream end in the column direction corresponding to the inclination of the upstream end. of Parts is characterized in that it is formed to be inclined with respect to the row direction.
  • the upstream end and the downstream end of the transfer electrodes adjacent in the column direction are formed to be inclined with respect to the row direction.
  • the most upstream portion of the end of the transfer electrode facing in the column direction at the upstream end To the most downstream portion at the downstream end becomes longer.
  • the region affected by both transfer voltages in the transfer channel expands in the column direction, so that the potential gradient of the transfer channel becomes gentle.
  • a section in which a potential gradient for charge transfer is formed becomes long when signal charges are transferred in the transfer channel.
  • the section in which the potential gradient is formed becomes longer, the section in which signal charges are transferred by diffusion can be shortened, and the section in which signal charges are transferred by drift can be lengthened.
  • the charge transfer rate due to drift is faster than that due to diffusion, and therefore the charge transfer rate in the transfer channel can be increased.
  • the solid-state imaging device further includes, in the semiconductor substrate, an element isolation region that separates the photoelectric conversion units adjacent in the column direction, and the upstream end of the transfer electrode adjacent in the column direction and the A region sandwiched between the downstream end portions may exist in the row direction of the element isolation region.
  • the center of the region sandwiched between the upstream end and the downstream end of the transfer electrode adjacent in the column direction may be present in the row direction of the element isolation region.
  • a region adjacent to the element isolation region in the row direction is affected by the element isolation region and has a low potential.
  • the region corresponding to the region sandwiched between the upstream end and the downstream end of the transfer electrode adjacent in the column direction in the transfer channel is a region where the gradient of the potential gradient increases during charge transfer. is there.
  • there is a region where the potential is low in the transfer channel because the region where the potential is low and the region where the gradient of the potential gradient increases during charge transfer are adjacent in the row direction. It is possible to prevent signal charges from being left behind.
  • the region corresponding to the center of the region sandwiched between the upstream end and the downstream end of the transfer electrode adjacent in the column direction has the maximum potential gradient during charge transfer. It is an area. Therefore, the region where the gradient of the potential gradient is maximum and the element isolation region are adjacent to each other in the row direction. Can be prevented.
  • the solid-state imaging device further includes a metal wiring provided above the plurality of transfer electrodes, arranged in each row and extending in the row direction, and having a lower resistance than the plurality of transfer electrodes, The transfer electrode of each row may be electrically connected to the metal wiring of the corresponding row through a contact.
  • transfer electrodes adjacent in the row direction may be separated from each other.
  • the rise and fall of the rectangular-wave-shaped transfer voltage is achieved by using metal wiring having a resistance lower than that of the transfer electrodes.
  • the charge transfer rate can be improved.
  • the connection portion (wiring) for connecting the transfer electrodes to each other in the same layer as the transfer electrode is not formed, the ground capacitance can be reduced. Therefore, further improvement in charge transfer speed and reduction in power consumption are expected.
  • the width of the metal wiring is larger than the width of the photoelectric conversion unit in the column direction, and an opening is provided in a region facing the photoelectric conversion unit in the metal wiring.
  • a region corresponding to between adjacent metal wirings in the direction may exist between the photoelectric conversion units adjacent in the column direction.
  • the metal wiring can be made to function as a light shielding film for a portion excluding the photoelectric conversion portion. Thereby, it can prevent that photoelectric conversion arises in area
  • the inclination of the end portions of the plurality of transfer electrodes with respect to the row direction may be the same for each transfer electrode.
  • each transfer electrode can be manufactured with a uniform layout, the charge transfer rate can be made uniform among the pixels. Moreover, since manufacturing variations can be suppressed, the yield is also improved.
  • the solid-state imaging device further includes, in the semiconductor substrate, an element isolation region that separates adjacent photoelectric conversion units in the column direction, and the upstream of the transfer electrodes adjacent in the column direction.
  • An imaginary line connecting the center of the region sandwiched between the end on the side and the downstream end in the tilt direction is adjacent to the imaginary line connecting the center of the transfer channel in the column direction in the column direction. It may be possible to intersect an imaginary line connecting the centers of the regions in the row direction.
  • the region corresponding to the point where the virtual line connecting the centers of the element isolation regions adjacent in the column direction in the row direction and the virtual line connecting the centers of the transfer channels in the column direction has a low potential.
  • a region passing through an imaginary line that connects the center of the region sandwiched between the upstream end and the downstream end of the adjacent transfer electrode in the column direction in the tilt direction has a potential gradient during charge transfer. This is a region where the slope of the is large.
  • FIG. 6 is an enlarged view of a portion indicated by (c)
  • FIG. 6 A cross-sectional view showing a configuration of the solid-state imaging device according to the first embodiment (AA ′ cross-sectional view of FIG.
  • FIG. 2 is a cross-sectional view taken along the line BB ′ of FIG.
  • FIG. 2 is a cross-sectional view (cross-sectional view taken along the line C-C ′ in FIG. 1) illustrating the configuration of the solid-state imaging device according to the first embodiment. It is a figure which shows typically the arrangement
  • FIG. 6 is a diagram corresponding to the position of a transfer electrode 104. It is a figure which shows typically the arrangement
  • FIG. (A) a diagram showing the shape of the transfer electrodes 904A to 904D in a plan view and the potential contour lines of the transfer channel 903 in a plan view, and (b) a two-dot chain line in FIG. 13
  • FIG. 14 is an enlarged view of a portion indicated by (c)
  • (c) is a diagram showing a potential cross section of a portion indicated by an arrow in FIG.
  • FIG. 1 is a diagram schematically illustrating an arrangement relationship of components of the solid-state imaging device according to the first embodiment.
  • components formed in the semiconductor substrate are indicated by broken lines, and components formed above the semiconductor substrate are indicated by solid lines.
  • the solid-state imaging device according to this embodiment includes a photoelectric conversion unit 102, a transfer channel 103, and a transfer electrode 104 as main components.
  • a plurality of photoelectric conversion units 102 that photoelectrically convert incident light from the outside and generate signal charges corresponding to the amount of light are formed in a matrix in the XY plane direction in the semiconductor substrate.
  • a transfer channel 103 serving as a transfer path for transferring signal charges for one column of the photoelectric conversion unit is formed between the photoelectric conversion unit columns formed of the photoelectric conversion units 102 arranged in the Y direction (column direction). ing.
  • the width of the transfer channel 103 in the X direction (row direction) is, for example, about 250 to 400 [nm].
  • a plurality of transfer electrodes 104 are formed above the transfer channel 103 in a form corresponding to the photoelectric conversion unit 102 on a one-to-one basis.
  • Each transfer electrode 104 reads the signal charge from the corresponding photoelectric conversion unit 102 and transfers the signal charge in the transfer channel 103 from the upstream side to the downstream side in the transfer direction (Y direction).
  • the potential gradient of the transfer channel 103 changes according to the transfer voltage applied to the transfer electrode 104.
  • the width of the transfer electrode 104 in the X direction is, for example, about 400 to 700 [nm].
  • “reading signal charges” means moving signal charges from the photoelectric conversion unit 102 to the transfer channel 103
  • transferring signal charges means transferring signal charges in the transfer direction in the transfer channel 103. Say to move.
  • the upstream end 104a of the transfer electrode 104 adjacent in the column direction is formed with an inclination of ⁇ with respect to the X direction, and the upstream end 104a is inclined.
  • the downstream end 104b of the transfer electrode 104 adjacent thereto in the column direction is formed with an inclination of ⁇ with respect to the X direction.
  • the length in the column direction of the region sandwiched between adjacent transfer electrodes in the Y direction is the electrode. It corresponds to the distance between the two and is indicated by len9.
  • the end of the transfer electrode 104 is inclined with respect to the X direction as in the present embodiment (FIG.
  • the length in the column direction of the region sandwiched between adjacent transfer electrodes in the Y direction is: This corresponds to the length from the most upstream portion of the upstream end portion 14a to the most downstream portion of the downstream end portion 14b, and is denoted by len1.
  • len1 and len9 the length in the column direction of the region sandwiched between adjacent transfer electrodes 104 in the Y direction is longer in len1 in the present embodiment.
  • the region of the transfer channel 103 that is affected by the transfer voltage applied to the transfer electrode 104 is expanded in the column direction.
  • the potential gradient formed in the transfer channel 103 becomes gentle, and accordingly, the section in which the potential gradient is formed becomes longer.
  • the section in which the potential gradient is formed becomes longer, the section in which signal charges are transferred by diffusion can be shortened, and the section in which signal charges are transferred by drift can be lengthened.
  • the charge transfer rate due to drift is faster than that due to diffusion, and therefore the charge transfer rate in the transfer channel 103 can be increased.
  • the inclination ⁇ of the end 104a on the upstream side and the inclination ⁇ of the end 104b on the downstream are equal, and the inclination ⁇ of the ends 104a and 104b of the transfer electrode 104 with respect to the X direction is all
  • the transfer electrodes 104 are equal to each other.
  • each transfer electrode 104 can be manufactured with a uniform layout, so that the charge transfer rate can be made uniform among the pixels.
  • the yield is also improved.
  • the width gap1 between the transfer electrodes 104 adjacent in the Y direction is preferably set to, for example, about 50 to 200 [nm] so as not to cause a potential dip between the adjacent transfer electrodes 104. Is about 80 [nm].
  • a region sandwiched between the upstream end 104a and the downstream end 104b of the transfer electrode 104 adjacent in the column direction is present in the row direction of the photoelectric conversion unit 102. Is formed.
  • transfer electrodes 104 adjacent in the X direction can be connected by the wiring 105 formed integrally with the transfer electrode 104.
  • a voltage having the same potential can be simultaneously applied to the transfer electrode 104.
  • the width of the wiring 105 in the Y direction is, for example, about 200 to 400 [nm].
  • FIG. 2A is an enlarged view of a region a in FIG.
  • the width in the X direction of the transfer channel 103 is W1
  • the distance from the upstream end 104a of the transfer electrode 104 to the upstream end 104a of the transfer electrode 104 adjacent in the column direction is L1.
  • the distance in the Y direction of the wiring 105 is L2.
  • L1-L2 corresponds to the length in the column direction between the upstream end portion and the downstream end portion of the adjacent wirings 105 in the column direction.
  • the setting range of the inclination ⁇ of the end portion 104a on the upstream side and the inclination ⁇ of the end portion 104b on the downstream side satisfy 0 ⁇ tan ⁇ ⁇ (L1-L2) / W1.
  • FIG. 2B is an example of an enlarged view of the region a in FIG. 1 when ⁇ is ⁇ max. As shown in FIG. 2B, the inclination of the virtual line I1 indicated by the two-dot chain line with respect to the row direction is ⁇ max, and the end portions 104a and 104b are formed to be parallel to the virtual line I1.
  • len1 ′ in FIG. 2B having a larger ⁇ is longer than len1 in FIG. 2A. Therefore, it is desirable that ⁇ be as large as possible within the above setting range. As ⁇ is larger, the region where the potential gradient is formed becomes longer and the charge transfer rate is improved.
  • ⁇ is desirably as large as possible within the above setting range
  • ⁇ exceeds ⁇ max
  • one transfer electrode 104 is formed over two or more pixels in the column direction, and therefore adjacent in the row direction.
  • the wiring 105 is connected between the photoelectric conversion unit 102 and another photoelectric conversion unit 102 adjacent in the Y direction (described later) in order to prevent the electric field due to the wiring 105 from affecting the photoelectric conversion unit 102 as much as possible. It corresponds to the element isolation region 106).
  • an element isolation region 106 for separating the photoelectric conversion units 102 adjacent in the column direction is formed in a region in the semiconductor substrate corresponding to the wiring 105.
  • the width of the element isolation region 106 in the Y direction is formed to be wider than the width of the wiring 105 in the Y direction.
  • FIG. 13A is a diagram showing the shape of the transfer electrodes 904A to 904D in plan view and the potential contour lines of the transfer channel 903 in plan view.
  • the transfer electrodes 904A and 904D are transfer electrodes to which a middle level transfer voltage (VM) is applied, and the transfer electrodes 904B and 904C are low level transfer voltages (VL) having a voltage value lower than the middle level. Is a transfer electrode to which is applied.
  • VM middle level transfer voltage
  • VL low level transfer voltages
  • the signal charge accumulated in the photoelectric conversion unit (photodiode) 902 is transferred in the transfer direction through the transfer channel (vertical CCD) 903 .
  • description will be given focusing on the photoelectric conversion unit 902 corresponding to the transfer electrode 904B, the transfer electrodes 904A and 904B, and the transfer channel 903 corresponding to the transfer electrodes 904A and 904B.
  • the signal charge accumulated in the photoelectric conversion unit 902 corresponding to the transfer electrode 904B is applied to a transfer voltage corresponding to the transfer electrode 904B by applying a read voltage (for example, a voltage higher than VM) to the transfer electrode 904B. Read to 903.
  • a read voltage for example, a voltage higher than VM
  • the transfer electrode 904B is applied to the transfer electrode 904B, and the potential of the transfer channel 903 corresponding to the transfer electrode 904B is lowered, thereby forming a potential gradient for charge transfer in the transfer channel 903.
  • the read signal charges are transferred from the transfer channel 903 corresponding to the transfer electrode 904B to the transfer channel 903 corresponding to the transfer electrode 904A, that is, the transfer channel 903 is transferred from the upstream side to the downstream side in the transfer direction. .
  • FIG. 13A corresponds to a potential contour line in a state where the above-described potential gradient for charge transfer is formed in the transfer channel 903.
  • FIG. 13B is an enlarged view of a region surrounded by a two-dot chain line in FIG. In the potential contour map of FIG. 13B, the points connecting the points with high potential are indicated by arrows.
  • FIG. 13C is a potential cross-sectional view of the transfer channel 903 shown corresponding to the position of the arrow in FIG.
  • FIG. 13C shows a potential cross-sectional view when the voltage applied to the transfer electrode 904B is changed from 0 [V] to ⁇ 6 [V], and the length of the potential gradient is indicated by D2. .
  • FIG. 3A is a diagram showing the shape of the transfer electrodes 104A to 104D in a plan view and the potential contour lines of the transfer channel 103 in a plan view.
  • the simulation experiment in the present embodiment is based on the shape of the transfer electrode 104 when ⁇ is ⁇ max. I went.
  • the lower side of FIG. 3A is a potential contour diagram of the transfer channel 103, and a portion surrounded by a two-dot chain line is a region where a potential gradient for charge transfer is formed in the transfer channel 103.
  • An enlarged view of the region indicated by the two-dot chain line is shown in FIG. 3 (b), and as in FIG. 13 (b), a point connecting points having high potential is indicated by an arrow.
  • FIG. 3C shows a potential cross section of the transfer channel 103 corresponding to the position of the arrow in FIG. Similarly to FIG. 13C, FIG. 3C also shows a potential cross-sectional view when the voltage applied to the transfer electrode 104B is changed from 0 [V] to ⁇ 6 [V], and the potential gradient is shown. The length of was indicated by D1.
  • the potential gradient length D1 of the present embodiment is the length of the potential gradient in Patent Document 1. It can be seen that it is longer than D2. That is, it was shown that the length of the potential gradient for signal charge transfer can be increased by forming the end portion of the transfer electrode 104 adjacent in the Y direction so as to be inclined with respect to the X direction. In addition, this is because the distance between the contour lines in FIG. 3 (b) is wider than the distance between the contour lines in FIG. 13 (b) when comparing the potential contour maps in FIG. 3 (b) and FIG. 13 (b). Can also be seen.
  • FIG. 4A is a cross-sectional view taken along line AA ′ in FIG. 1
  • FIG. 5 is a cross-sectional view taken along the line BB ′ of FIG.
  • a gate insulating film 117 made of a silicon oxide film is formed on the main surface in the Z direction of the semiconductor substrate 101a.
  • a transfer electrode 104 and a wiring 105 made of polysilicon are selectively formed on the gate insulating film 117.
  • An interlayer insulating film 118 and a light shielding film 119 are stacked on the transfer electrode 104 and the wiring 105 so as to cover them.
  • a BPSG film (Boron Phosphorous Silicate Glass) 120 for flattening a step between a region where the transfer electrode 104 and the wiring 105 are formed and a region where the transfer electrode 104 and the wiring 105 are not formed is formed, and the color filter 121 is formed on the BPSG film 120. Is formed.
  • a top lens 122 is formed on the color filter 121.
  • the semiconductor substrate 101a is an n-type silicon substrate, and a p-type well region 101b made of p-type impurities is formed on the main surface side of the semiconductor substrate 101a. Is formed.
  • the p-type well region 101b will be described in detail with reference to FIGS.
  • the p-type well region 101b includes a first n-type semiconductor well region 111 and a high-concentration first p formed on the first n-type semiconductor well region 111. And a high-concentration first p-type element isolation region 123 formed near the interface between the first n-type semiconductor well region 111 and the first p-type semiconductor well region 112.
  • the first p-type element isolation region 123 forms the element isolation region 106 (FIG. 1), and the width of the first p-type element isolation region 123 in the Y direction is the same as that of the wiring 105 in the Y direction.
  • the range is preferably equal to or greater than the width, for example, in the range of 100 to 400 [nm].
  • the first p-type element isolation region 123 exists in the well region 101 b in the semiconductor substrate 101 a corresponding to the wiring 105.
  • the p-type well region 101 b further includes a second high-concentration second region formed near the interface between the first n-type semiconductor well region 111 and the first p-type semiconductor well region 112.
  • P-type element isolation region 116 is
  • the second n-type semiconductor well region 114 forms the transfer channel 103 (FIG. 1).
  • the width of the second n-type semiconductor well region 114 in the X direction is, for example, 250 to 400 [nm].
  • the depth is, for example, 50 to 100 [nm].
  • the second n-type semiconductor well region 114 is formed, for example, by implanting arsenic or the like, and the impurity concentration of the implanted arsenic is, for example, 4.0 to 6.0E17 [cm ⁇ 3 ].
  • the transfer electrode 104 exists in a region on the gate insulating film 117 corresponding to the second n-type semiconductor well region 114.
  • the width in the X direction between the first p-type element isolation region 123 (element isolation region 106) and the second n-type semiconductor well region 114 (transfer channel 103) is, for example, 25 to 100 [ nm].
  • the downstream end of the photoelectric conversion unit 902 is aligned with the downstream end of the transfer electrode 904 as indicated by a virtual line I9.
  • the other downstream end of the transfer electrode 104 is shifted upstream by the shift width len2 from the other downstream end of the photoelectric conversion unit 102. This can also be seen from FIGS. 4A and 4B.
  • the D-D ′ cross section in the solid-state imaging device (FIG. 12) according to Patent Document 1 corresponds to the C-C ′ cross section in the solid-state imaging device (FIG. 1) according to the present embodiment.
  • the DD ′ cross section relating to the solid-state imaging device according to Patent Document 1 is not particularly illustrated, but in this DD ′ cross section, the region where the transfer electrode 104 is divided as shown in the region b of FIG. 5 does not appear. .
  • the direction of inclination of the end of the transfer electrode is not particularly limited. As shown in FIG. 6A, the end of the transfer electrode 104 may be inclined in a direction opposite to the direction of inclination of the end of the transfer electrode 104 shown in FIGS. Similar effects can be obtained.
  • the upstream end (or downstream end) of the adjacent transfer electrode in the Y direction (column direction) is inclined with respect to the X direction (row direction) means that in the Y direction A line segment connecting the most upstream part and the most downstream part at the upstream end of the adjacent transfer electrode (or a line connecting the most upstream part and the most downstream part at the downstream end. ")" Is inclined with respect to the X direction, and the case where the end of the transfer electrode 104 is not formed in a straight line is also included. For example, as shown in FIG. 6B, even when the end portion of the transfer electrode 104 is formed in a stepped shape, the “upstream end portion (or the downstream end portion of the transfer electrode adjacent in the Y direction” described above.
  • the “end portion” is inclined with respect to the row direction.
  • the number of steps at the end formed in a staircase shape is not particularly limited. Although not particularly illustrated, even if the end portion of the transfer electrode 104 is V-shaped, the same effect as described above can be obtained.
  • FIG. 7 is a diagram schematically illustrating the arrangement relationship of the components of the solid-state imaging device according to the second embodiment.
  • the differences from the first embodiment are the position of the region sandwiched between the upstream end portion 204a and the downstream end portion 204b of the transfer electrode 204 adjacent in the Y direction, and the transfer adjacent in the X direction.
  • the electrode is connected by the metal wiring 205.
  • the region sandwiched between the end portions 104 a and 104 b of the transfer electrode 104 is located in the row direction of the photoelectric conversion unit 102.
  • the region sandwiched between the end portions 204 a and 204 b of the transfer electrode 204 exists in the row direction of the element isolation region 206.
  • the metal wiring 205 is made of, for example, a metal material such as tungsten, aluminum, or copper.
  • the diameter of the contact 208 is set smaller than the width of the transfer electrode 204 in the X direction, and is, for example, 200 [nm] to 350 [nm].
  • the width len3 in the Y direction of the metal wiring 205 in the region located between adjacent photoelectric conversion units 202 in the Y direction is, for example, 100 [nm] to 400 [nm].
  • the above metal material has a lower resistance than the polysilicon constituting the transfer electrode 204, the rising and falling of the rectangular wave shape are steeper with respect to the transfer electrode 204 than in the case of the first embodiment.
  • a transfer voltage can be applied, and therefore the charge transfer rate can be improved.
  • FIG. 8A is a diagram showing a potential cross-sectional view of the transfer channel 203 according to the second embodiment in correspondence with the position of the transfer electrode 204.
  • FIG. 8B is a diagram showing a potential cross-sectional view related to the transfer channel 103 according to the first embodiment in association with the position of the transfer electrode 104.
  • FIG. 8 there are components that are not shown for the sake of simplicity.
  • the element isolation region 106 is for isolating adjacent photoelectric conversion units 102, and thus has a low potential.
  • the influence of the potential of the element isolation region 106 may affect the potential of the transfer channel 103 as well. That is, as indicated by a broken line in the potential cross-sectional view, there is a portion where the potential is locally lowered in the region corresponding to the element isolation region 106 and the X direction in the transfer channel 103. Therefore, at the time of signal charge transfer, as shown by the solid line in the potential cross-sectional view, there is a portion where the potential is locally lowered in the bottom region where the gradient of the potential gradient becomes small due to the influence of the element isolation region 106. Therefore, the part where the potential is locally lowered may cause the signal charge to be left behind. Further, the part where the potential is locally lowered becomes more remarkable as the pixel size becomes particularly small.
  • the transfer channel 203 in this embodiment has a portion where the potential is locally lowered due to the influence of the element isolation region 206 that separates the photoelectric conversion unit 202.
  • the part where the potential is locally lowered due to the influence of the element isolation region 206 is located near the middle where the gradient of the potential gradient is maximum. Yes. Therefore, in the present embodiment, the above problem does not occur.
  • a virtual line I2 connecting the center of the transfer channel 203 in the Y direction intersects with a virtual line I4 connecting the center of the element isolation region 206 adjacent in the Y direction in the X direction.
  • the region corresponding to the point (o) is a region where the manufacturing potential tends to be low.
  • a region passing through a virtual line I3 that connects the center of the region sandwiched between the upstream end portion 204a and the downstream end portion 204b of the transfer electrode 204 adjacent in the Y direction in the inclination direction is This is a region where the gradient of the potential gradient becomes large during charge transfer.
  • the region sandwiched between the end portions 204a and 204b of the transfer electrode 204 exists in the row direction of the element isolation region 206. More preferably, the center of the region sandwiched between the end portions 204a and 204b of the transfer electrode 204 is the center. If the element isolation region 206 exists in the row direction, the above effect can be obtained.
  • the inclination angle of the end portions 204a and 204b of the transfer electrode 204 with respect to the X direction need not be within the setting range as in the first embodiment, and the upper limit of the inclination angle depends on the configuration of the transfer electrode 204. It will never be decided.
  • the transfer electrode 204 may be formed over two or more pixels in the Y direction. In FIG. 9, illustration of the metal wirings 205 and 205c is omitted.
  • FIG. 10 is a diagram schematically illustrating the arrangement relationship of the components of the solid-state imaging device according to the third embodiment. The difference from the second embodiment is that the shape of the metal wiring 305 is different. In FIG. 10, the element isolation region is not shown.
  • the width of the metal wiring 305 in the present embodiment in the Y direction is larger than the width of the photoelectric conversion unit 302 in the column direction.
  • an opening is provided in a region of the metal wiring 305 facing the photoelectric conversion unit 302 so that light is not blocked from entering the photoelectric conversion unit 302.
  • a region corresponding to an area between adjacent metal wirings 305 in the Y direction exists between the photoelectric conversion units 302 adjacent in the Y direction.
  • the transfer electrodes 304c in the last row are also connected to each other by a metal wiring 305c. Further, the metal wiring 305 (or the metal wiring 305 c) and the transfer electrode 304 (or the transfer electrode 304 c) are electrically connected through the contact 308.
  • the width len4 (distance between adjacent metal wirings 305) in the Y direction of the region corresponding to the space between adjacent metal wirings 305 in the Y direction is, for example, 150 [nm] to 300 [nm]. Further, the width len5 in the Y direction of the metal wiring 305 in the region between the photoelectric conversion units 302 adjacent in the Y direction is, for example, 100 [nm] to 200 [nm].
  • the width of the metal wiring 305 in the Y direction can be increased, and the cross-sectional area of the metal wiring 305 can be expanded. Since the resistance of the metal wiring 305 is inversely proportional to the cross-sectional area, the resistance of the metal wiring 305 can be further reduced as the cross-sectional area of the metal wiring 305 is expanded. Therefore, a transfer voltage with a steep rising and falling of a rectangular wave shape can be applied to the transfer electrode 304, which can contribute to an improvement in charge transfer speed.
  • the metal wiring 305 is also formed on the corresponding region between the photoelectric conversion unit 302 and the transfer channel 303, the read voltage is applied to the metal wiring 305 on this region in addition to the transfer electrode 304. Is applied. Therefore, compared to the first and second embodiments, signal charges can be easily read from the photoelectric conversion unit 302 to the transfer channel 303, and thus the width of the transfer electrode 304 in the row direction can be reduced. As a result, the opening area of the photoelectric conversion unit 302 can be increased, and the sensitivity of the solid-state imaging device can be increased.
  • the metal wiring 305 can be made to function as a light-shielding film for the portion excluding the photoelectric conversion portion 302. As a result, it is possible to prevent photoelectric conversion from occurring in a region other than the photoelectric conversion unit 302 in the semiconductor substrate, and as a result, it is possible to contribute to reducing smear noise.
  • the transfer electrode is formed so that the slope of the upstream end and the slope of the downstream end are equal, but the present invention is not limited to this. It is sufficient that the upstream end is inclined with respect to the row direction, and the downstream end is inclined with respect to the row direction corresponding to this inclination. The upstream end and the downstream end are inclined. The inclination may be different. However, the end on the downstream side needs to be inclined corresponding to the inclination of the upstream end, and the downstream end is inclined in a direction opposite to the inclination direction of the upstream end. Cases shall not be included.
  • FIG. 11 is a diagram schematically showing the arrangement relationship of the components of the solid-state imaging device according to this modification.
  • the signal charge accumulated in the photoelectric conversion unit 402 is read out to the transfer channel 403 when a read voltage is applied to the transfer electrode 404.
  • the signal charge transferred to the transfer channel 403 at the downstream end in the transfer direction is transferred to the horizontal transfer channel 407 by applying a predetermined voltage to the transfer electrode 404c in the last row.
  • the signal charge transferred to the horizontal transfer channel 407 is transferred from the upstream side to the downstream side in the transfer direction by applying a horizontal transfer voltage to the corresponding horizontal transfer electrode 409. At this time, the end of the horizontal transfer electrode 409 is formed to be inclined with respect to the Y direction.
  • the horizontal transfer channel 407 is also a one-pixel one-electrode type in which one horizontal transfer electrode 409 is arranged for one photoelectric conversion unit row formed of the photoelectric conversion units 402.
  • the width of the horizontal transfer channel 407 in the Y direction is larger than the width of the transfer channel 403 in the X direction, for example, several [ ⁇ m] to several tens [ ⁇ m]. Therefore, in the horizontal transfer channel 407, signal charges are easily left behind as compared with the transfer channel 403. Further, in the horizontal transfer channel 407, signal charges are normally transferred at a transfer frequency as high as, for example, about 30 to 50 [MHz], and the problem of remaining signal charges becomes significant. Therefore, the effect of increasing the charge transfer rate by tilting the end of the horizontal transfer electrode 409 is significant.
  • the present invention can be suitably used for electronic devices such as digital still cameras and digital video cameras that require high image quality, for example.

Abstract

Provided is a solid-state image pickup device that has a charge transfer rate that can withstand a transfer frequency becoming more high-speed. The solid-state image pickup device is provided with: a plurality of photoelectric conversion units (102) that are formed matrix-like, and that are for converting incident light into signal charges; transfer channels (103) that are formed between columns of adjacent photoelectric conversion units (102); and a plurality of transfer electrodes (104) that are formed in the column direction with a pattern corresponding one-to-one to the photoelectric conversion units (102), and that are for reading signal charges from the corresponding photoelectric conversion units (102), and transferring the signal charges from the upstream side to the downstream side in the transfer direction within the transfer channels (103). Upstream-side end sections (104a) of transfer electrodes (104), which are adjacent to each other in the column direction, are formed to be inclined with respect to the row direction, and downstream-side end sections (104b) of the transfer electrodes (104), which are adjacent to the upstream-side end sections (104a) in the column direction, are formed to be inclined with respect to the row direction in accordance with the inclination of the upstream-side end sections (104a).

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１画素１電極型の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 1-pixel 1-electrode type CCD (Charge Coupled Device) type solid-state imaging device.
　ＣＣＤイメージセンサに代表される固体撮像装置は、デジタルスチルカメラやデジタルビデオカメラ等に広く利用されており、その需要は益々増加している。近年の固体撮像装置の多画素化、小型化の要請に伴い、画素は高密度に配列され、画素サイズは縮小される傾向にある。 Solid-state imaging devices typified by CCD image sensors are widely used in digital still cameras, digital video cameras, and the like, and their demand is increasing. With the recent demand for a large number of pixels and a reduction in size of a solid-state imaging device, the pixels are arranged with high density and the pixel size tends to be reduced.
　ところが、画素サイズを縮小した場合、単位画素の開口面積が減少し、各画素の光電変換部の感度特性が低下するという不具合が生じてしまう。そこで、光電変換部で発生した信号電荷を転送方向に転送するための転送チャネルの幅を縮小することにより、開口面積を維持するという方法を採ることが考えられる。しかしながら、転送チャネルの幅を縮小すると、転送チャネルの取り扱い信号電荷量が低下してしまうという別の問題が発生する。 However, when the pixel size is reduced, the opening area of the unit pixel is reduced, and the sensitivity characteristic of the photoelectric conversion unit of each pixel is deteriorated. Therefore, it is conceivable to adopt a method of maintaining the opening area by reducing the width of the transfer channel for transferring the signal charge generated in the photoelectric conversion unit in the transfer direction. However, if the width of the transfer channel is reduced, another problem arises that the amount of signal charge handled by the transfer channel decreases.
　上記問題を解決するため、転送チャネルの幅を縮小しつつ、転送チャネルの取り扱い信号電荷量を増加させる技術が開示されている（特許文献１）。 In order to solve the above problem, a technique for increasing the amount of signal charges handled in the transfer channel while reducing the width of the transfer channel is disclosed (Patent Document 1).
　図１２は、特許文献１に記載の固体撮像装置に係る構成要素の配置関係を模式的に示す図である。 FIG. 12 is a diagram schematically showing the arrangement relationship of the components related to the solid-state imaging device described in Patent Document 1.
　図１２に示すように、特許文献１に記載の固体撮像装置では、半導体基板内のＸ－Ｙ面方向に、入射光を信号電荷に変換するための複数のフォトダイオード（光電変換部）９０２が行列状に配置されている。複数のフォトダイオード９０２がＹ方向（列方向）に配置されることでフォトダイオード９０２の列をなしており、隣接するフォトダイオードの列の間には、当該フォトダイオード１列分の信号電荷を転送するための垂直ＣＣＤ（転送チャネル）９０３が形成されている。 As shown in FIG. 12, the solid-state imaging device described in Patent Document 1 includes a plurality of photodiodes (photoelectric conversion units) 902 for converting incident light into signal charges in the XY plane direction in the semiconductor substrate. Arranged in a matrix. A plurality of photodiodes 902 are arranged in the Y direction (column direction) to form a column of photodiodes 902, and signal charges corresponding to one column of photodiodes are transferred between adjacent photodiode columns. For this purpose, a vertical CCD (transfer channel) 903 is formed.
　垂直ＣＣＤ９０３の上方には、フォトダイオード９０２と１対１に対応する形態で、対応するフォトダイオード９０２から信号電荷を読み出して垂直ＣＣＤ９０３内を転送方向の上流側から下流側へ転送させる転送電極９０４が形成されている。Ｘ方向において隣接する転送電極９０４同士は、接続部９０５により接続されており、Ｙ方向において隣接するフォトダイオード９０２を分離するために、接続部９０５に対応する半導体基板内の領域には素子分離領域が形成されている。 Above the vertical CCD 903, there is a transfer electrode 904 that reads the signal charge from the corresponding photodiode 902 in a one-to-one correspondence with the photodiode 902 and transfers the signal in the vertical CCD 903 from the upstream side to the downstream side in the transfer direction. Is formed. The transfer electrodes 904 adjacent in the X direction are connected to each other by a connection portion 905. In order to isolate the photodiode 902 adjacent in the Y direction, an element isolation region is provided in a region in the semiconductor substrate corresponding to the connection portion 905. Is formed.
　特許文献１に記載の構成では、１つのフォトダイオード９０２に対して１つの転送電極９０４を配置した、いわゆる１画素１電極型となっている。したがって、例えば１つのフォトダイオードに対して２つの転送電極を配置した場合（いわゆる１画素２電極型の場合）と比較して、垂直ＣＣＤ９０３の取り扱い信号電荷量を２倍とすることができる。 The configuration described in Patent Document 1 is a so-called one-pixel one-electrode type in which one transfer electrode 904 is arranged for one photodiode 902. Therefore, for example, the amount of signal charges handled by the vertical CCD 903 can be doubled as compared with a case where two transfer electrodes are arranged for one photodiode (a so-called one-pixel two-electrode type).
特開平３－９７３８１号公報Japanese Patent Laid-Open No. 3-97381
　ところで、最近では、テレビ等に代表される表示装置の高精細化が進行しており、それに追従して、固体撮像装置の高精細な動画像への対応が要求されている。この要求に対しては、転送周波数の高速化により対応することが可能である。しかしながら、転送周波数の高速化は、換言すると信号電荷の転送が行える期間の短縮化である。電荷転送を行える時間が短縮されると、転送電極から次行の転送電極へ信号電荷を転送させるのに必要な時間が十分に確保されないことによる信号電荷の取り残しが発生し、その結果、画質劣化の問題が招来する。この信号電荷の取り残しを抑制するには、転送電極から次行の転送電極への電荷転送に必要な時間の短縮化、すなわち、電荷転送速度の高速化が有効である。 By the way, in recent years, display devices represented by televisions and the like have been improved in definition, and accordingly, it is required to deal with high-definition moving images of solid-state imaging devices. This requirement can be met by increasing the transfer frequency. However, increasing the transfer frequency is, in other words, reducing the period during which signal charges can be transferred. If the time during which charge transfer can be performed is shortened, signal charge may be left behind due to insufficient time required to transfer signal charge from the transfer electrode to the transfer electrode in the next row, resulting in image quality degradation. The problem of inviting. In order to suppress the remaining of the signal charge, it is effective to shorten the time required for charge transfer from the transfer electrode to the transfer electrode of the next row, that is, to increase the charge transfer rate.
　本発明は、上記した問題に鑑み、転送周波数の高速化に耐え得る電荷転送速度を有する固体撮像装置の提供をその目的とする。 In view of the above problems, an object of the present invention is to provide a solid-state imaging device having a charge transfer rate that can withstand an increase in transfer frequency.
　上記課題を解決するために、本発明に係る固体撮像装置は、半導体基板内に行列状に形成され、入射光を信号電荷に変換する複数の光電変換部と、前記半導体基板内における、隣接する光電変換部の列の間に形成された転送チャネルと、前記半導体基板上における前記転送チャネルに対応する領域に、前記光電変換部と１対１に対応する形態で列方向に複数形成され、対応する光電変換部から信号電荷を読み出して前記転送チャネル内を転送方向の上流側から下流側へ転送させる転送電極と、を備え、前記複数の転送電極を平面視した場合に、列方向において隣接する転送電極の端部のうち上流側の端部が行方向に対して傾斜して形成されるとともに、前記上流側の端部の傾斜に対応してこれと列方向において隣接する転送電極の下流側の端部が行方向に対して傾斜して形成されていることを特徴とする。 In order to solve the above problems, a solid-state imaging device according to the present invention is formed in a matrix in a semiconductor substrate, and is adjacent to a plurality of photoelectric conversion units that convert incident light into signal charges, in the semiconductor substrate. A plurality of transfer channels formed between columns of photoelectric conversion units and a region corresponding to the transfer channel on the semiconductor substrate are formed in the column direction in a one-to-one correspondence with the photoelectric conversion units. And a transfer electrode that reads the signal charge from the photoelectric conversion unit and transfers the signal in the transfer channel from the upstream side to the downstream side in the transfer direction, and is adjacent in the column direction when the plurality of transfer electrodes are viewed in plan view The upstream end of the transfer electrode is formed to be inclined with respect to the row direction, and the downstream side of the transfer electrode adjacent to the upstream end in the column direction corresponding to the inclination of the upstream end. of Parts is characterized in that it is formed to be inclined with respect to the row direction.
　隣接する転送電極に異なる転送電圧を印加した場合、転送チャネルにおける各転送電極に相当する領域では、それぞれの転送電圧の影響を受けてポテンシャルが異なることとなる。また、両領域の境界付近では、両方の転送電圧の影響を受けて電荷転送用のポテンシャル勾配が形成される。信号電荷の転送は、このポテンシャル勾配を利用して行われる。 When different transfer voltages are applied to adjacent transfer electrodes, potentials in regions corresponding to the transfer electrodes in the transfer channel are affected by the transfer voltages. In the vicinity of the boundary between both regions, a potential gradient for charge transfer is formed under the influence of both transfer voltages. The signal charge is transferred using this potential gradient.
　上記の構成によれば、列方向において隣接する転送電極の上流側の端部と下流側の端部が行方向に対して傾斜して形成されている。このようにすることで、転送電極の端部が行方向に対して平行である場合と比較して、列方向に向かい合う転送電極の端部のうち、上流側の端部における最も上流側の部分から下流側の端部における最も下流側の部分までの長さが長くなる。このようにすることで、転送チャネルにおける両方の転送電圧の影響を受ける領域が列方向に広がるので、転送チャネルのポテンシャル勾配が緩やかになる。これに伴って、転送チャネルでの信号電荷の転送時において、電荷転送用のポテンシャル勾配が形成される区間が長くなる。ポテンシャル勾配が形成される区間が長くなる分、拡散により信号電荷が転送される区間を短くするとともに、ドリフトにより信号電荷が転送される区間を長くすることができる。ドリフトによる電荷転送速度は拡散による場合に比して速く、したがって、転送チャネルにおける電荷転送速度を高速化することが可能となる。 According to the above configuration, the upstream end and the downstream end of the transfer electrodes adjacent in the column direction are formed to be inclined with respect to the row direction. By doing in this way, compared with the case where the end of the transfer electrode is parallel to the row direction, the most upstream portion of the end of the transfer electrode facing in the column direction at the upstream end To the most downstream portion at the downstream end becomes longer. By doing so, the region affected by both transfer voltages in the transfer channel expands in the column direction, so that the potential gradient of the transfer channel becomes gentle. Along with this, a section in which a potential gradient for charge transfer is formed becomes long when signal charges are transferred in the transfer channel. As the section in which the potential gradient is formed becomes longer, the section in which signal charges are transferred by diffusion can be shortened, and the section in which signal charges are transferred by drift can be lengthened. The charge transfer rate due to drift is faster than that due to diffusion, and therefore the charge transfer rate in the transfer channel can be increased.
　以上説明したように、転送周波数の高速化に耐え得る電荷転送速度を有する固体撮像装置を提供することができる。 As described above, it is possible to provide a solid-state imaging device having a charge transfer rate that can withstand a higher transfer frequency.
　本発明に係る固体撮像装置は、さらに、前記半導体基板内に、列方向において隣接する光電変換部を分離する素子分離領域を備え、列方向において隣接する転送電極の前記上流側の端部と前記下流側の端部とで挟まれた領域が、前記素子分離領域の行方向に存在することとしてもよい。 The solid-state imaging device according to the present invention further includes, in the semiconductor substrate, an element isolation region that separates the photoelectric conversion units adjacent in the column direction, and the upstream end of the transfer electrode adjacent in the column direction and the A region sandwiched between the downstream end portions may exist in the row direction of the element isolation region.
　さらに、列方向において隣接する転送電極の前記上流側の端部と前記下流側の端部とで挟まれた領域の中心が、前記素子分離領域の行方向に存在することとしてもよい。 Furthermore, the center of the region sandwiched between the upstream end and the downstream end of the transfer electrode adjacent in the column direction may be present in the row direction of the element isolation region.
　転送チャネルにおける、素子分離領域の行方向において隣接する領域は、素子分離領域の影響を受けて、ポテンシャルが低くなっている。一方、転送チャネルにおける、列方向において隣接する転送電極の上流側の端部と下流側の端部とで挟まれた領域に対応する領域は、電荷転送時においてポテンシャル勾配の傾きが大きくなる領域である。上記の構成によれば、ポテンシャルが低くなっている領域と電荷転送時においてポテンシャル勾配の傾きが大きくなる領域が行方向に隣接していることにより、転送チャネルにおいてポテンシャルが低くなっている領域があることによる信号電荷の取り残しを防ぐことができる。 In the transfer channel, a region adjacent to the element isolation region in the row direction is affected by the element isolation region and has a low potential. On the other hand, the region corresponding to the region sandwiched between the upstream end and the downstream end of the transfer electrode adjacent in the column direction in the transfer channel is a region where the gradient of the potential gradient increases during charge transfer. is there. According to the above configuration, there is a region where the potential is low in the transfer channel because the region where the potential is low and the region where the gradient of the potential gradient increases during charge transfer are adjacent in the row direction. It is possible to prevent signal charges from being left behind.
　さらに、転送チャネルにおける、列方向において隣接する転送電極の上流側の端部と下流側の端部とで挟まれた領域の中心に対応する領域は、電荷転送時においてポテンシャル勾配の傾きが最大となる領域である。したがって、ポテンシャル勾配の傾きが最大となる領域と素子分離領域が行方向に隣接していることで、転送チャネルにおいてポテンシャルが低くなっている領域があることによる信号電荷の取り残しを、より効果的に防ぐことができる。 Further, in the transfer channel, the region corresponding to the center of the region sandwiched between the upstream end and the downstream end of the transfer electrode adjacent in the column direction has the maximum potential gradient during charge transfer. It is an area. Therefore, the region where the gradient of the potential gradient is maximum and the element isolation region are adjacent to each other in the row direction. Can be prevented.
　本発明に係る固体撮像装置は、さらに、前記複数の転送電極の上方に設けられ、各行に配置されるとともに行方向に延び、かつ、前記複数の転送電極よりも低抵抗な金属配線を備え、前記各行の転送電極は、対応する行の金属配線とコンタクトを介して電気的に接続されていることとしてもよい。 The solid-state imaging device according to the present invention further includes a metal wiring provided above the plurality of transfer electrodes, arranged in each row and extending in the row direction, and having a lower resistance than the plurality of transfer electrodes, The transfer electrode of each row may be electrically connected to the metal wiring of the corresponding row through a contact.
　さらに、行方向において隣接する転送電極同士が分離されていることとしてもよい。 Furthermore, transfer electrodes adjacent in the row direction may be separated from each other.
　転送電極よりも低抵抗な金属配線を用いることにより、転送電極と同じ材料からなる配線で同じ行の転送電極を電気的に接続する場合と比較して、矩形波状の転送電圧の立ち上がりおよび立ち下がりを急峻にすることができ、電荷転送速度の向上を図ることができる。また、転送電極と同じ層に転送電極同士を接続する接続部（配線）を形成しない分、接地容量を低減することができる。したがって、さらなる電荷転送速度の向上、ならびに消費電力の低減が期待される。 Compared to the case where the transfer electrodes in the same row are electrically connected by the wiring made of the same material as that of the transfer electrodes, the rise and fall of the rectangular-wave-shaped transfer voltage is achieved by using metal wiring having a resistance lower than that of the transfer electrodes. The charge transfer rate can be improved. In addition, since the connection portion (wiring) for connecting the transfer electrodes to each other in the same layer as the transfer electrode is not formed, the ground capacitance can be reduced. Therefore, further improvement in charge transfer speed and reduction in power consumption are expected.
　本発明に係る固体撮像装置は、前記金属配線の幅が、前記光電変換部の列方向の幅よりも大きく、前記金属配線における前記光電変換部と対向する領域に開口が設けられており、列方向において隣接する金属配線の間に相当する領域が、列方向において隣接する光電変換部の間に存在することとしてもよい。 In the solid-state imaging device according to the present invention, the width of the metal wiring is larger than the width of the photoelectric conversion unit in the column direction, and an opening is provided in a region facing the photoelectric conversion unit in the metal wiring. A region corresponding to between adjacent metal wirings in the direction may exist between the photoelectric conversion units adjacent in the column direction.
　上記のような構成にすることで、金属配線を光電変換部を除く部分に対する遮光膜として機能させることが可能となる。これにより、半導体基板のうち光電変換部以外の領域で光電変換が起こることを防止し、スミアノイズ低減に貢献できる。また、金属配線の列方向の幅が広くなる、すなわち、金属配線の断面積が大きくなる分、さらなる低抵抗化を図ることが可能となり、より電荷転送速度を向上させることができる。さらに、光電変換部と転送チャネルの間に対応する領域上にも金属配線が形成されているため、転送電極に加えて、この領域上にある金属配線に対しても読み出し電圧が印加される。そうすると、光電変換部と転送チャネルの間に対応する領域上に金属配線が形成されていない場合と比較して、光電変換部から転送チャネルへ電荷が読み出しやすくなるため、転送電極の行方向の幅を縮小できる。その結果、光電変換部の開口面積が拡大でき、固体撮像装置の高感度化を図ることができる。 With the above configuration, the metal wiring can be made to function as a light shielding film for a portion excluding the photoelectric conversion portion. Thereby, it can prevent that photoelectric conversion arises in area | regions other than a photoelectric conversion part among semiconductor substrates, and can contribute to a smear noise reduction. Further, since the width of the metal wiring in the column direction is increased, that is, the cross-sectional area of the metal wiring is increased, the resistance can be further reduced and the charge transfer rate can be further improved. Furthermore, since the metal wiring is also formed on the corresponding region between the photoelectric conversion unit and the transfer channel, the read voltage is applied to the metal wiring on this region in addition to the transfer electrode. This makes it easier to read charges from the photoelectric conversion unit to the transfer channel than when no metal wiring is formed on the corresponding region between the photoelectric conversion unit and the transfer channel. Can be reduced. As a result, the opening area of the photoelectric conversion unit can be increased, and the sensitivity of the solid-state imaging device can be increased.
　本発明に係る固体撮像装置は、前記複数の転送電極における端部の行方向に対する傾斜は、各転送電極で等しいこととしてもよい。 In the solid-state imaging device according to the present invention, the inclination of the end portions of the plurality of transfer electrodes with respect to the row direction may be the same for each transfer electrode.
　このようにすることで、各転送電極を均一なレイアウトで製造できるために、各画素間で電荷転送速度を均一化できる。また、製造バラツキも抑制できるため、歩留も向上する。 In this way, since each transfer electrode can be manufactured with a uniform layout, the charge transfer rate can be made uniform among the pixels. Moreover, since manufacturing variations can be suppressed, the yield is also improved.
　本発明に係る固体撮像装置は、前記固体撮像装置は、さらに、前記半導体基板内に、列方向において隣接する光電変換部を分離する素子分離領域を備え、列方向において隣接する転送電極の前記上流側の端部と前記下流側の端部とで挟まれた領域の中心を前記傾斜方向に結ぶ仮想線が、前記転送チャネルの中心を列方向に結ぶ仮想線と、列方向において隣接する素子分離領域の中心を行方向に結んだ仮想線と交差するとしてもよい。 In the solid-state imaging device according to the present invention, the solid-state imaging device further includes, in the semiconductor substrate, an element isolation region that separates adjacent photoelectric conversion units in the column direction, and the upstream of the transfer electrodes adjacent in the column direction. An imaginary line connecting the center of the region sandwiched between the end on the side and the downstream end in the tilt direction is adjacent to the imaginary line connecting the center of the transfer channel in the column direction in the column direction. It may be possible to intersect an imaginary line connecting the centers of the regions in the row direction.
　転送チャネルにおける、列方向において隣接する素子分離領域の中心を行方向に結んだ仮想線と前記転送チャネルの中心を列方向に結ぶ仮想線とが交差する点に対応する領域は、ポテンシャルが低くなりやすい。一方、列方向において隣接する転送電極の前記上流側の端部と前記下流側の端部とで挟まれた領域の中心を前記傾斜方向に結ぶ仮想線を通る領域は、電荷転送時においてポテンシャル勾配の傾きが大きくなる領域である。これら三本の仮想線が交差することにより、ポテンシャルが低くなりやすい領域と電荷転送時においてポテンシャル勾配の傾きが最も大きくなる領域とが重なるようになる。したがって、転送チャネルにおいてポテンシャルが低くなっている領域があることによる信号電荷の取り残しを、効率的に防ぐことができる。 In the transfer channel, the region corresponding to the point where the virtual line connecting the centers of the element isolation regions adjacent in the column direction in the row direction and the virtual line connecting the centers of the transfer channels in the column direction has a low potential. Cheap. On the other hand, a region passing through an imaginary line that connects the center of the region sandwiched between the upstream end and the downstream end of the adjacent transfer electrode in the column direction in the tilt direction has a potential gradient during charge transfer. This is a region where the slope of the is large. When these three virtual lines intersect, a region where the potential is likely to be low and a region where the gradient of the potential gradient is the largest during charge transfer overlap. Therefore, it is possible to efficiently prevent the signal charges from being left due to the presence of a region having a low potential in the transfer channel.
第１の実施形態に係る固体撮像装置の構成要素の配置関係を模式的に示す図である。It is a figure which shows typically the arrangement | positioning relationship of the component of the solid-state imaging device which concerns on 1st Embodiment. 図１における領域ａの拡大図である。It is an enlarged view of the area | region a in FIG. （ａ）平面視した場合の転送電極１０４Ａ～１０４Ｄの形状と、平面視した場合の転送チャネル１０３のポテンシャルの等高線とを対応させて示す図と、（ｂ）図５（ａ）における二点鎖線で示す部分の拡大図と、（ｃ）図５（ｂ）における矢印で示す部分のポテンシャル断面を示す図である。(A) A diagram showing the shape of the transfer electrodes 104A to 104D in plan view and the contour lines of the potential of the transfer channel 103 in plan view, and (b) a two-dot chain line in FIG. 5 (a) FIG. 6 is an enlarged view of a portion indicated by (c), and (c) is a diagram showing a potential cross section of a portion indicated by an arrow in FIG. （ａ）第１の実施形態に係る固体撮像装置の構成を示す断面図（図１のＡ－Ａ’断面図）と、（ｂ）第１の実施形態に係る固体撮像装置の構成を示す断面図（図１のＢ－Ｂ’断面図）である。(A) A cross-sectional view showing a configuration of the solid-state imaging device according to the first embodiment (AA ′ cross-sectional view of FIG. 1), and (b) a cross-section showing a configuration of the solid-state imaging device according to the first embodiment. FIG. 2 is a cross-sectional view taken along the line BB ′ of FIG. 第１の実施形態に係る固体撮像装置の構成を示す断面図（図１のＣ－Ｃ’断面図）である。FIG. 2 is a cross-sectional view (cross-sectional view taken along the line C-C ′ in FIG. 1) illustrating the configuration of the solid-state imaging device according to the first embodiment. 第１の実施形態の変形例に係る固体撮像装置の構成要素の配置関係を模式的に示す図である。It is a figure which shows typically the arrangement | positioning relationship of the component of the solid-state imaging device which concerns on the modification of 1st Embodiment. 第２の実施形態に係る固体撮像装置の構成要素の配置関係を模式的に示す図である。It is a figure which shows typically the arrangement | positioning relationship of the component of the solid-state imaging device which concerns on 2nd Embodiment. （ａ）第２の実施形態に係る転送チャネル２０３のポテンシャル断面図を転送電極２０４の位置に対応させて示す図と、（ｂ）第１の実施形態に係る転送チャネル１０３に係るポテンシャル断面図を転送電極１０４の位置に対応させて示す図である。(A) The figure which shows the potential sectional drawing of the transfer channel 203 concerning 2nd Embodiment corresponding to the position of the transfer electrode 204, (b) The potential sectional view concerning the transfer channel 103 concerning 1st Embodiment FIG. 6 is a diagram corresponding to the position of a transfer electrode 104. 第２の実施形態の別の形態に係る固体撮像装置の構成要素の配置関係を模式的に示す図である。It is a figure which shows typically the arrangement | positioning relationship of the component of the solid-state imaging device which concerns on another form of 2nd Embodiment. 第３の実施形態に係る固体撮像装置の構成要素の配置関係を模式的に示す図である。It is a figure which shows typically the arrangement | positioning relationship of the component of the solid-state imaging device which concerns on 3rd Embodiment. 変形例（２）に係る固体撮像装置の構成要素の配置関係を模式的に示す図である。It is a figure which shows typically the arrangement | positioning relationship of the component of the solid-state imaging device which concerns on a modification (2). 特許文献１に係る固体撮像装置の構成要素の配置関係を模式的に示す図である。It is a figure which shows typically the arrangement | positioning relationship of the component of the solid-state imaging device which concerns on patent document 1. FIG. （ａ）平面視した場合の転送電極９０４Ａ～９０４Ｄの形状と、平面視した場合の転送チャネル９０３のポテンシャルの等高線とを対応させて示す図と、（ｂ）図１３（ａ）における二点鎖線で示す部分の拡大図と、（ｃ）図１３（ｂ）における矢印で示す部分のポテンシャル断面を示す図である。(A) a diagram showing the shape of the transfer electrodes 904A to 904D in a plan view and the potential contour lines of the transfer channel 903 in a plan view, and (b) a two-dot chain line in FIG. 13 (a) FIG. 14 is an enlarged view of a portion indicated by (c), and (c) is a diagram showing a potential cross section of a portion indicated by an arrow in FIG.
　以下、本発明を実施するための形態を、図面を参照しながら説明する。 Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
　［第１の実施形態］
　〈固体撮像装置の構成要素の配置関係〉
　図１は、第１の実施形態に係る固体撮像装置の構成要素の配置関係を模式的に示す図である。本図において半導体基板内に形成された構成要素については破線で、半導体基板上方に形成された構成要素については実線で示している。本実施形態に係る固体撮像装置は、主な構成として光電変換部１０２，転送チャネル１０３，転送電極１０４を備える。 [First Embodiment]
<Relationship of components of solid-state imaging device>
FIG. 1 is a diagram schematically illustrating an arrangement relationship of components of the solid-state imaging device according to the first embodiment. In the figure, components formed in the semiconductor substrate are indicated by broken lines, and components formed above the semiconductor substrate are indicated by solid lines. The solid-state imaging device according to this embodiment includes a photoelectric conversion unit 102, a transfer channel 103, and a transfer electrode 104 as main components.
　図１に示すように、半導体基板内のＸ－Ｙ面方向に、外部からの入射光を光電変換し光量に応じた信号電荷を発生させる複数の光電変換部１０２が行列状に形成されている。Ｙ方向（列方向）に配置された光電変換部１０２からなる光電変換部列の間には、当該光電変換部１列分の信号電荷を転送する際の転送経路となる転送チャネル１０３が形成されている。転送チャネル１０３のＸ方向（行方向）の幅は、例えば、２５０～４００［ｎｍ］程度である。 As shown in FIG. 1, a plurality of photoelectric conversion units 102 that photoelectrically convert incident light from the outside and generate signal charges corresponding to the amount of light are formed in a matrix in the XY plane direction in the semiconductor substrate. . A transfer channel 103 serving as a transfer path for transferring signal charges for one column of the photoelectric conversion unit is formed between the photoelectric conversion unit columns formed of the photoelectric conversion units 102 arranged in the Y direction (column direction). ing. The width of the transfer channel 103 in the X direction (row direction) is, for example, about 250 to 400 [nm].
　転送チャネル１０３の上方には、光電変換部１０２と１対１に対応する形態で、複数の転送電極１０４が形成されている。各転送電極１０４は、対応する光電変換部１０２から信号電荷を読み出し、転送チャネル１０３内を転送方向（Ｙ方向）の上流側から下流側へ転送させる。具体的には、転送電極１０４に印加される転送電圧に応じて、転送チャネル１０３のポテンシャル勾配が変化する。これにより、転送チャネル１０３において、光電変換部１０２から読み出された信号電荷を転送方向へ転送することができる。転送電極１０４のＸ方向の幅は、例えば、４００～７００［ｎｍ］程度である。ここで、「信号電荷を読み出す」とは、光電変換部１０２から転送チャネル１０３へ信号電荷を移動させることを言い、「信号電荷を転送する」とは、転送チャネル１０３において信号電荷を転送方向に移動させることを言う。 A plurality of transfer electrodes 104 are formed above the transfer channel 103 in a form corresponding to the photoelectric conversion unit 102 on a one-to-one basis. Each transfer electrode 104 reads the signal charge from the corresponding photoelectric conversion unit 102 and transfers the signal charge in the transfer channel 103 from the upstream side to the downstream side in the transfer direction (Y direction). Specifically, the potential gradient of the transfer channel 103 changes according to the transfer voltage applied to the transfer electrode 104. Thereby, in the transfer channel 103, the signal charge read from the photoelectric conversion unit 102 can be transferred in the transfer direction. The width of the transfer electrode 104 in the X direction is, for example, about 400 to 700 [nm]. Here, “reading signal charges” means moving signal charges from the photoelectric conversion unit 102 to the transfer channel 103, and “transferring signal charges” means transferring signal charges in the transfer direction in the transfer channel 103. Say to move.
　また、転送方向の下流側終端の転送チャネル１０３上に形成されている、最終行の転送電極１０４ｃに所定電圧が印加されることにより、転送チャネル１０３の転送方向の下流側終端に転送された信号電荷が、転送チャネル１０３から水平転送チャネル１０７へ送られる。 In addition, a signal transferred to the downstream end in the transfer direction of the transfer channel 103 by applying a predetermined voltage to the transfer electrode 104c in the last row formed on the transfer channel 103 at the downstream end in the transfer direction. Charge is transferred from the transfer channel 103 to the horizontal transfer channel 107.
　次に、転送電極１０４の形状に着目すると、列方向において隣接する転送電極１０４の上流側の端部１０４ａがＸ方向に対してθ傾斜して形成されるとともに、上流側の端部１０４ａの傾斜θに対応してこれと列方向において隣接する転送電極１０４の下流側の端部１０４ｂがＸ方向に対してθ傾斜して形成されている。 Next, focusing on the shape of the transfer electrode 104, the upstream end 104a of the transfer electrode 104 adjacent in the column direction is formed with an inclination of θ with respect to the X direction, and the upstream end 104a is inclined. Corresponding to θ, the downstream end 104b of the transfer electrode 104 adjacent thereto in the column direction is formed with an inclination of θ with respect to the X direction.
　ここで、Ｙ方向において隣接する転送電極で挟まれた領域の列方向の長さに注目する。先ず、特許文献１のように転送電極９０４の端部がＸ方向に対して平行である場合（図１２）、Ｙ方向において隣接する転送電極９０４で挟まれた領域の列方向の長さは電極間距離に相当し、ｌｅｎ９で示される。一方、本実施形態のように転送電極１０４の端部がＸ方向に対して傾斜している場合（図１）、Ｙ方向において隣接する転送電極で挟まれた領域の列方向の長さは、上流側の端部１４ａにおける最も上流側の部分から下流側の端部１４ｂにおける最も下流側の部分までの長さに対応し、ｌｅｎ１で示される。ｌｅｎ１とｌｅｎ９を比較すると、本実施形態のｌｅｎ１の方が、Ｙ方向において隣接する転送電極１０４で挟まれた領域の列方向の長さが長くなる。 Note here the length in the column direction of the region sandwiched between adjacent transfer electrodes in the Y direction. First, when the end of the transfer electrode 904 is parallel to the X direction as in Patent Document 1 (FIG. 12), the length in the column direction of the region sandwiched between adjacent transfer electrodes 904 in the Y direction is the electrode. It corresponds to the distance between the two and is indicated by len9. On the other hand, when the end of the transfer electrode 104 is inclined with respect to the X direction as in the present embodiment (FIG. 1), the length in the column direction of the region sandwiched between adjacent transfer electrodes in the Y direction is: This corresponds to the length from the most upstream portion of the upstream end portion 14a to the most downstream portion of the downstream end portion 14b, and is denoted by len1. When comparing len1 and len9, the length in the column direction of the region sandwiched between adjacent transfer electrodes 104 in the Y direction is longer in len1 in the present embodiment.
　転送電極１０４で挟まれた領域の長さが長くなることで、転送チャネル１０３における、転送電極１０４に印加される転送電圧の影響を受ける領域が列方向に広がる。そうすると、転送チャネル１０３に形成されるポテンシャル勾配が緩やかになり、これに伴って、ポテンシャル勾配が形成される区間が長くなる。ポテンシャル勾配が形成される区間が長くなる分、拡散により信号電荷が転送される区間を短くするとともに、ドリフトにより信号電荷が転送される区間を長くすることができる。ドリフトによる電荷転送速度は拡散による場合に比して速く、したがって、転送チャネル１０３における電荷転送速度を高速化することが可能となる。この原理の検証については、後ほど図３を用いて詳細に説明する。 By increasing the length of the region sandwiched between the transfer electrodes 104, the region of the transfer channel 103 that is affected by the transfer voltage applied to the transfer electrode 104 is expanded in the column direction. As a result, the potential gradient formed in the transfer channel 103 becomes gentle, and accordingly, the section in which the potential gradient is formed becomes longer. As the section in which the potential gradient is formed becomes longer, the section in which signal charges are transferred by diffusion can be shortened, and the section in which signal charges are transferred by drift can be lengthened. The charge transfer rate due to drift is faster than that due to diffusion, and therefore the charge transfer rate in the transfer channel 103 can be increased. The verification of this principle will be described later in detail with reference to FIG.
　また、本実施形態においては、上流側における端部１０４ａの傾斜θと下流側における端部１０４ｂの傾斜θは等しく、かつ、転送電極１０４における端部１０４ａ，１０４ｂのＸ方向に対する傾斜θは、全ての転送電極１０４で等しくなるように形成されている。Ｘ方向に対する傾斜θを全ての転送電極１０４で等しくすることによって、各転送電極１０４を均一なレイアウトで製造できるために、各画素間で電荷転送速度を均一化できる。また、製造バラツキも抑制できるため、歩留も向上する。また、Ｙ方向において隣接する転送電極１０４の間の幅ｇａｐ１は、隣接する転送電極１０４の間でポテンシャルディップが発生しないように、例えば、５０～２００［ｎｍ］程度とするのが好ましく、より好ましくは８０［ｎｍ］程度である。 In the present embodiment, the inclination θ of the end 104a on the upstream side and the inclination θ of the end 104b on the downstream are equal, and the inclination θ of the ends 104a and 104b of the transfer electrode 104 with respect to the X direction is all The transfer electrodes 104 are equal to each other. By making the inclination θ with respect to the X direction equal for all the transfer electrodes 104, each transfer electrode 104 can be manufactured with a uniform layout, so that the charge transfer rate can be made uniform among the pixels. Moreover, since manufacturing variations can be suppressed, the yield is also improved. Further, the width gap1 between the transfer electrodes 104 adjacent in the Y direction is preferably set to, for example, about 50 to 200 [nm] so as not to cause a potential dip between the adjacent transfer electrodes 104. Is about 80 [nm].
　さらに、本実施形態においては、列方向において隣接する転送電極１０４の上流側の端部１０４ａと下流側の端部１０４ｂとで挟まれた領域が、光電変換部１０２の行方向に存在するように形成されている。このような構成とすることで、各行の転送電極１０４において、Ｘ方向において隣接する転送電極１０４同士を、転送電極１０４と一体的に形成された配線１０５により接続することができるので、同じ行の転送電極１０４に同電位の電圧を同時に印加することができる。配線１０５のＹ方向の幅は、例えば、２００～４００［ｎｍ］程度である。 Further, in the present embodiment, a region sandwiched between the upstream end 104a and the downstream end 104b of the transfer electrode 104 adjacent in the column direction is present in the row direction of the photoelectric conversion unit 102. Is formed. With such a configuration, in the transfer electrodes 104 of each row, transfer electrodes 104 adjacent in the X direction can be connected by the wiring 105 formed integrally with the transfer electrode 104. A voltage having the same potential can be simultaneously applied to the transfer electrode 104. The width of the wiring 105 in the Y direction is, for example, about 200 to 400 [nm].
　ここで、Ｘ方向において隣接する転送電極１０４同士を配線１０５により接続するためには、傾斜θが所定の範囲内でなければならない。このことについて、図２を用いて説明する。図２（ａ）は，図１における領域ａの拡大図である。 Here, in order to connect the transfer electrodes 104 adjacent in the X direction by the wiring 105, the inclination θ must be within a predetermined range. This will be described with reference to FIG. FIG. 2A is an enlarged view of a region a in FIG.
　図２（ａ）において、転送チャネル１０３のＸ方向の幅をＷ１、転送電極１０４の上流側の端部１０４ａから、列方向において隣接する転送電極１０４の上流側の端部１０４ａまでの距離をＬ１、配線１０５のＹ方向の距離をＬ２とする。また、Ｌ１－Ｌ２は、列方向において隣接する配線１０５の上流側における端部と下流側における端部の間の、列方向の長さに相当する。 In FIG. 2A, the width in the X direction of the transfer channel 103 is W1, and the distance from the upstream end 104a of the transfer electrode 104 to the upstream end 104a of the transfer electrode 104 adjacent in the column direction is L1. The distance in the Y direction of the wiring 105 is L2. L1-L2 corresponds to the length in the column direction between the upstream end portion and the downstream end portion of the adjacent wirings 105 in the column direction.
　上流側における端部１０４ａの傾斜θ、ならびに、下流側における端部１０４ｂの傾斜θの設定範囲は、０＜ｔａｎθ≦（Ｌ１－Ｌ２）／Ｗ１を満たすことが望ましい。以下、ｔａｎθ＝（Ｌ１－Ｌ２）／Ｗ１を満たす場合のθをθｍａｘとする。 It is desirable that the setting range of the inclination θ of the end portion 104a on the upstream side and the inclination θ of the end portion 104b on the downstream side satisfy 0 <tan θ ≦ (L1-L2) / W1. Hereinafter, θ satisfying tan θ = (L1−L2) / W1 is defined as θmax.
　図２（ｂ）は、θがθｍａｘである場合の図１における領域ａの拡大図の一例である。図２（ｂ）に示すように、行方向に対する二点鎖線で示す仮想線Ｉ１の傾斜がθｍａｘであり、端部１０４ａ，１０４ｂはこの仮想線Ｉ１と平行になるように形成されている。 FIG. 2B is an example of an enlarged view of the region a in FIG. 1 when θ is θmax. As shown in FIG. 2B, the inclination of the virtual line I1 indicated by the two-dot chain line with respect to the row direction is θmax, and the end portions 104a and 104b are formed to be parallel to the virtual line I1.
　図２（ａ），（ｂ）の比較から分かるように、図２（ａ）におけるｌｅｎ１よりも、θがより大きい図２（ｂ）の場合におけるｌｅｎ１’の方が長くなる。したがって、上記の設定範囲内であればθは可能な限り大きい方が望ましく、θが大きい程、よりポテンシャル勾配が形成される領域が長くなり、電荷転送速度は向上する。 As can be seen from the comparison between FIGS. 2A and 2B, len1 ′ in FIG. 2B having a larger θ is longer than len1 in FIG. 2A. Therefore, it is desirable that θ be as large as possible within the above setting range. As θ is larger, the region where the potential gradient is formed becomes longer and the charge transfer rate is improved.
　θは上記の設定範囲内で可能な限り大きい方が望ましいものの、θがθｍａｘを超えると、１つの転送電極１０４が列方向に２画素以上にわたって形成されることとなるので、行方向において隣接する転送電極１０４同士を配線１０５で接続できなくなる。すなわち、上記の式で規定されるθの設定範囲は、転送電極１０４同士を配線１０５で接続するための要件である。なお、例えば、Ｗ１＝３５０ｎｍ、Ｌ１＝１６００ｎｍ、Ｌ２＝３００ｎｍとした場合、θｍａｘはおよそ７５［ｄｅｇ］となる。 Although θ is desirably as large as possible within the above setting range, when θ exceeds θmax, one transfer electrode 104 is formed over two or more pixels in the column direction, and therefore adjacent in the row direction. The transfer electrodes 104 cannot be connected to each other by the wiring 105. That is, the setting range of θ defined by the above formula is a requirement for connecting the transfer electrodes 104 with the wiring 105. For example, when W1 = 350 nm, L1 = 1600 nm, and L2 = 300 nm, θmax is approximately 75 [deg].
　図１に戻り、固体撮像装置の構成要素の配置関係について説明を続ける。図１において、配線１０５による電界の影響をできるだけ光電変換部１０２に及ぼさないようにするために、配線１０５は光電変換部１０２とＹ方向において隣接する他の光電変換部１０２との間（後述する素子分離領域１０６に相当する。）の上方を通るように形成されている。 Referring back to FIG. 1, the description of the arrangement relationship of the components of the solid-state imaging device is continued. In FIG. 1, the wiring 105 is connected between the photoelectric conversion unit 102 and another photoelectric conversion unit 102 adjacent in the Y direction (described later) in order to prevent the electric field due to the wiring 105 from affecting the photoelectric conversion unit 102 as much as possible. It corresponds to the element isolation region 106).
　配線１０５に対応する半導体基板内の領域には、列方向において隣接する光電変換部１０２を分離するための素子分離領域１０６が形成されている。素子分離領域１０６のＹ方向の幅は、配線１０５のＹ方向の幅より広くなるように形成されている。このようにすることで、配線１０５による電界が、光電変換部１０２に及ぼす影響を低減することができる。 In a region in the semiconductor substrate corresponding to the wiring 105, an element isolation region 106 for separating the photoelectric conversion units 102 adjacent in the column direction is formed. The width of the element isolation region 106 in the Y direction is formed to be wider than the width of the wiring 105 in the Y direction. Thus, the influence of the electric field generated by the wiring 105 on the photoelectric conversion unit 102 can be reduced.
　〈シミュレーション実験〉
　転送電極１０４の端部１０４ａ，１０４ｂを行方向に対して傾斜させることによって、転送チャネル１０３におけるポテンシャル勾配が長くなることを実際に確認するために、シミュレーション実験を行った。その結果について、図３，１３を用いて説明する。 <Simulation experiment>
In order to actually confirm that the potential gradient in the transfer channel 103 becomes longer by inclining the end portions 104a and 104b of the transfer electrode 104 with respect to the row direction, a simulation experiment was performed. The result will be described with reference to FIGS.
　先ず、図１３を用いて、特許文献１の場合のシミュレーション結果について説明する。 First, a simulation result in the case of Patent Document 1 will be described with reference to FIG.
　図１３（ａ）は、平面視した場合の転送電極９０４Ａ～９０４Ｄの形状と、平面視した場合の転送チャネル９０３のポテンシャルの等高線とを対応させて示す図である。 FIG. 13A is a diagram showing the shape of the transfer electrodes 904A to 904D in plan view and the potential contour lines of the transfer channel 903 in plan view.
　また、転送電極９０４Ａ，９０４Ｄはミドルレベルの転送電圧（ＶＭ）が印加されている転送電極であり、転送電極９０４Ｂ，９０４Ｃは、ミドルレベルよりも低い電圧値であるローレベルの転送電圧（ＶＬ）が印加されている転送電極である。 The transfer electrodes 904A and 904D are transfer electrodes to which a middle level transfer voltage (VM) is applied, and the transfer electrodes 904B and 904C are low level transfer voltages (VL) having a voltage value lower than the middle level. Is a transfer electrode to which is applied.
　ここで、光電変換部（フォトダイオード）９０２で蓄積された信号電荷が、転送チャネル（垂直ＣＣＤ）９０３を転送方向に転送されるまでの流れについて説明する。ここでは、転送電極９０４Ｂに対応する光電変換部９０２、転送電極９０４Ａ，９０４Ｂ、ならびに転送電極９０４Ａ，９０４Ｂに対応する転送チャネル９０３に着目して説明する。先ず、転送電極９０４Ｂに対応する光電変換部９０２で蓄積された信号電荷は、転送電極９０４Ｂに読み出し電圧（例えば、ＶＭよりも高い電圧）が印加されることにより、転送電極９０４Ｂに対応する転送チャネル９０３に読み出される。そして、転送電極９０４ＢにＶＬの転送電圧を印加し、転送電極９０４Ｂに対応する転送チャネル９０３のポテンシャルを低くすることで、転送チャネル９０３に電荷転送用のポテンシャル勾配を形成する。これにより、読み出された信号電荷は、転送電極９０４Ｂに対応する転送チャネル９０３から転送電極９０４Ａに対応する転送チャネル９０３に、すなわち、転送チャネル９０３を転送方向の上流側から下流側へ転送される。 Here, a flow until the signal charge accumulated in the photoelectric conversion unit (photodiode) 902 is transferred in the transfer direction through the transfer channel (vertical CCD) 903 will be described. Here, description will be given focusing on the photoelectric conversion unit 902 corresponding to the transfer electrode 904B, the transfer electrodes 904A and 904B, and the transfer channel 903 corresponding to the transfer electrodes 904A and 904B. First, the signal charge accumulated in the photoelectric conversion unit 902 corresponding to the transfer electrode 904B is applied to a transfer voltage corresponding to the transfer electrode 904B by applying a read voltage (for example, a voltage higher than VM) to the transfer electrode 904B. Read to 903. Then, a VL transfer voltage is applied to the transfer electrode 904B, and the potential of the transfer channel 903 corresponding to the transfer electrode 904B is lowered, thereby forming a potential gradient for charge transfer in the transfer channel 903. Thus, the read signal charges are transferred from the transfer channel 903 corresponding to the transfer electrode 904B to the transfer channel 903 corresponding to the transfer electrode 904A, that is, the transfer channel 903 is transferred from the upstream side to the downstream side in the transfer direction. .
　図１３（ａ）における二点鎖線で囲った部分が、転送チャネル９０３に上記の電荷転送用のポテンシャル勾配が形成されている状態のポテンシャル等高線に対応する。図１３（ｂ）は、図１３（ａ）における二点鎖線で囲った領域の拡大図である。図１３（ｂ）のポテンシャル等高線図における、ポテンシャルが高い地点を結んだものを矢印で示した。そして、図１３（ｃ）は、図１３（ｂ）における矢印の位置に対応させて示す、転送チャネル９０３のポテンシャル断面図である。図１３（ｃ）では、転送電極９０４Ｂに印加される電圧を０［Ｖ］から－６［Ｖ］に変化させた場合のポテンシャル断面図を示しており、ポテンシャル勾配の長さをＤ２で示した。 13A corresponds to a potential contour line in a state where the above-described potential gradient for charge transfer is formed in the transfer channel 903. FIG. 13B is an enlarged view of a region surrounded by a two-dot chain line in FIG. In the potential contour map of FIG. 13B, the points connecting the points with high potential are indicated by arrows. FIG. 13C is a potential cross-sectional view of the transfer channel 903 shown corresponding to the position of the arrow in FIG. FIG. 13C shows a potential cross-sectional view when the voltage applied to the transfer electrode 904B is changed from 0 [V] to −6 [V], and the length of the potential gradient is indicated by D2. .
　ここまで、特許文献１の場合のシミュレーション結果について説明した。続いて、図３を用いて、本実施形態の場合のシミュレーション結果について説明する。図３（ａ）～（ｃ）の各図は、図１３の（ａ）～（ｃ）とそれぞれ対応している。 So far, the simulation results in the case of Patent Document 1 have been described. Subsequently, a simulation result in the case of the present embodiment will be described with reference to FIG. 3A to 3C correspond to FIGS. 13A to 13C, respectively.
　図３（ａ）は、平面視した場合の転送電極１０４Ａ～１０４Ｄの形状と、平面視した場合の転送チャネル１０３のポテンシャルの等高線とを対応させて示す図である。図３（ａ）の上側に転送電極９０４Ａ～９０４ＤのＸＹ平面における概略形状を示しているように、本実施形態の場合におけるシミュレーション実験は、θがθｍａｘである場合の転送電極１０４の形状に基づいて行った。図３（ａ）の下側が転送チャネル１０３のポテンシャル等高線図であり、二点鎖線で囲っている部分は転送チャネル１０３において電荷転送用のポテンシャル勾配が形成されている領域である。この二点鎖線で示す領域の拡大図を図３（ｂ）に示し、図１３（ｂ）と同じく、ポテンシャルが高い地点を結んだものを矢印で示している。 FIG. 3A is a diagram showing the shape of the transfer electrodes 104A to 104D in a plan view and the potential contour lines of the transfer channel 103 in a plan view. As shown in FIG. 3A on the upper side of the schematic shape of the transfer electrodes 904A to 904D in the XY plane, the simulation experiment in the present embodiment is based on the shape of the transfer electrode 104 when θ is θmax. I went. The lower side of FIG. 3A is a potential contour diagram of the transfer channel 103, and a portion surrounded by a two-dot chain line is a region where a potential gradient for charge transfer is formed in the transfer channel 103. An enlarged view of the region indicated by the two-dot chain line is shown in FIG. 3 (b), and as in FIG. 13 (b), a point connecting points having high potential is indicated by an arrow.
　そして、図３（ｃ）は、転送チャネル１０３のポテンシャル断面を、図３（ｂ）における矢印の位置に対応させて示す図である。図１３（ｃ）と同じく、図３（ｃ）においても転送電極１０４Ｂに印加される電圧を０［Ｖ］から－６［Ｖ］に変化させた場合のポテンシャル断面図を示しており、ポテンシャル勾配の長さをＤ１で示した。 FIG. 3C shows a potential cross section of the transfer channel 103 corresponding to the position of the arrow in FIG. Similarly to FIG. 13C, FIG. 3C also shows a potential cross-sectional view when the voltage applied to the transfer electrode 104B is changed from 0 [V] to −6 [V], and the potential gradient is shown. The length of was indicated by D1.
　図３（ｃ）におけるポテンシャル勾配の長さＤ１と図１３（ｃ）におけるポテンシャル勾配の長さＤ２とを比較すると、本実施形態のポテンシャル勾配の長さＤ１は、特許文献１におけるポテンシャル勾配の長さＤ２よりも長いことが分かる。すなわち、Ｙ方向において隣接する転送電極１０４の端部をＸ方向に対して傾斜して形成することで、信号電荷転送用のポテンシャル勾配の長さを長くすることができることが示された。また、このことは、図３（ｂ）と図１３（ｂ）のポテンシャル等高線図を比較において、図３（ｂ）等高線の間隔が、図１３（ｂ）の等高線の間隔に比して広いことからも見て取れる。 Comparing the potential gradient length D1 in FIG. 3C with the potential gradient length D2 in FIG. 13C, the potential gradient length D1 of the present embodiment is the length of the potential gradient in Patent Document 1. It can be seen that it is longer than D2. That is, it was shown that the length of the potential gradient for signal charge transfer can be increased by forming the end portion of the transfer electrode 104 adjacent in the Y direction so as to be inclined with respect to the X direction. In addition, this is because the distance between the contour lines in FIG. 3 (b) is wider than the distance between the contour lines in FIG. 13 (b) when comparing the potential contour maps in FIG. 3 (b) and FIG. 13 (b). Can also be seen.
　〈固体撮像装置の断面図〉
　続いて、固体撮像装置の構成について説明する。図４，図５（ａ）は、本実施形態の固体撮像装置の構成を示す断面図であり、図４（ａ）は図１のＡ－Ａ’断面図、図４（ｂ）は図１のＢ－Ｂ’断面図、図５は図１のＣ－Ｃ’断面図である。 <Cross-sectional view of solid-state imaging device>
Next, the configuration of the solid-state imaging device will be described. 4 and 5A are cross-sectional views showing the configuration of the solid-state imaging device according to the present embodiment. FIG. 4A is a cross-sectional view taken along line AA ′ in FIG. 1, and FIG. FIG. 5 is a cross-sectional view taken along the line BB ′ of FIG.
　図４（ａ），（ｂ）に示すように、本実施形態の固体撮像装置では、半導体基板１０１ａにおけるＺ方向の主面上にシリコン酸化膜からなるゲート絶縁膜１１７が形成されている。ゲート絶縁膜１１７上には、ポリシリコンからなる転送電極１０４，配線１０５が選択的に形成されている。転送電極１０４，配線１０５上には、これらを覆うように層間絶縁膜１１８及び遮光膜１１９が積層されている。さらに、転送電極１０４，配線１０５が形成された領域と形成されていない領域との段差を平坦化するためのＢＰＳＧ膜（Ｂｏｒｏｎ　Ｐｈｏｓｐｈｏｒｏｕｓ　Ｓｉｌｉｃａｔｅ　Ｇｌａｓｓ）１２０が形成され、ＢＰＳＧ膜１２０上にカラーフィルタ１２１が形成されている。カラーフィルタ１２１上にはトップレンズ１２２が形成されている。 As shown in FIGS. 4A and 4B, in the solid-state imaging device of this embodiment, a gate insulating film 117 made of a silicon oxide film is formed on the main surface in the Z direction of the semiconductor substrate 101a. On the gate insulating film 117, a transfer electrode 104 and a wiring 105 made of polysilicon are selectively formed. An interlayer insulating film 118 and a light shielding film 119 are stacked on the transfer electrode 104 and the wiring 105 so as to cover them. Further, a BPSG film (Boron Phosphorous Silicate Glass) 120 for flattening a step between a region where the transfer electrode 104 and the wiring 105 are formed and a region where the transfer electrode 104 and the wiring 105 are not formed is formed, and the color filter 121 is formed on the BPSG film 120. Is formed. A top lens 122 is formed on the color filter 121.
　図４（ａ），（ｂ），図５に示すように、半導体基板１０１ａはｎ型のシリコン基板であり、半導体基板１０１ａの主面側にはｐ型の不純物からなるｐ型のウェル領域１０１ｂが形成されている。このｐ型のウェル領域１０１ｂについて、図４（ａ）及び図５を用いて詳細に説明する。 As shown in FIGS. 4A, 4B, and 5, the semiconductor substrate 101a is an n-type silicon substrate, and a p-type well region 101b made of p-type impurities is formed on the main surface side of the semiconductor substrate 101a. Is formed. The p-type well region 101b will be described in detail with reference to FIGS.
　ｐ型のウェル領域１０１ｂは、図４（ａ）に示すように、第１のｎ型半導体ウェル領域１１１と、第１のｎ型半導体ウェル領域１１１上に形成された高濃度の第１のｐ型半導体ウェル領域１１２と、第１のｎ型半導体ウェル領域１１１と第１のｐ型半導体ウェル領域１１２との界面付近に形成された高濃度の第１のｐ型素子分離領域１２３とを有する。 As shown in FIG. 4A, the p-type well region 101b includes a first n-type semiconductor well region 111 and a high-concentration first p formed on the first n-type semiconductor well region 111. And a high-concentration first p-type element isolation region 123 formed near the interface between the first n-type semiconductor well region 111 and the first p-type semiconductor well region 112.
　図４において、第１のｐ型素子分離領域１２３が素子分離領域１０６（図１）を構成しており、第１のｐ型素子分離領域１２３のＹ方向の幅は、配線１０５のＹ方向の幅と同等、又はそれ以上の範囲であるのが好ましく、例えば、１００～４００［ｎｍ］の範囲である。また、配線１０５に対応する半導体基板１０１ａにおけるウェル領域１０１ｂ内に第１のｐ型素子分離領域１２３が存在している。 In FIG. 4, the first p-type element isolation region 123 forms the element isolation region 106 (FIG. 1), and the width of the first p-type element isolation region 123 in the Y direction is the same as that of the wiring 105 in the Y direction. The range is preferably equal to or greater than the width, for example, in the range of 100 to 400 [nm]. In addition, the first p-type element isolation region 123 exists in the well region 101 b in the semiconductor substrate 101 a corresponding to the wiring 105.
　図５に示すように、ｐ型のウェル領域１０１ｂは、さらに、第１のｎ型半導体ウェル領域１１１と第１のｐ型半導体ウェル領域１１２との界面付近に形成された高濃度の第２のｐ型素子分離領域１１５と、第１のｎ型半導体ウェル領域１１１及び第１のｐ型半導体ウェル領域１１２から離れた領域に形成された第２のｐ型半導体ウェル領域１１３と、第２のｐ型半導体ウェル領域１１３上に形成された第２のｎ型半導体ウェル領域１１４と、第２のｐ型半導体ウェル領域１１３と第２のｎ型半導体ウェル領域１１４との界面付近に形成された第３のｐ型素子分離領域１１６とを有する。 As shown in FIG. 5, the p-type well region 101 b further includes a second high-concentration second region formed near the interface between the first n-type semiconductor well region 111 and the first p-type semiconductor well region 112. a p-type element isolation region 115; a second p-type semiconductor well region 113 formed in a region away from the first n-type semiconductor well region 111 and the first p-type semiconductor well region 112; and a second p-type A second n-type semiconductor well region 114 formed on the p-type semiconductor well region 113 and a third n-type formed near the interface between the second p-type semiconductor well region 113 and the second n-type semiconductor well region 114. P-type element isolation region 116.
　図５において、第２のｎ型半導体ウェル領域１１４が転送チャネル１０３（図１）を構成しており、第２のｎ型半導体ウェル領域１１４のＸ方向の幅は、例えば、２５０～４００［ｎｍ］の範囲であり、深さは例えば、５０～１００［ｎｍ］である。第２のｎ型半導体ウェル領域１１４は、例えば、ヒ素等を注入することで形成され、注入されるヒ素の不純物濃度は、例えば、４．０～６．０Ｅ１７［ｃｍ－３］である。図４（ｂ），図５に示すように、第２のｎ型半導体ウェル領域１１４に相当するゲート絶縁膜１１７上の領域に転送電極１０４が存在している。 In FIG. 5, the second n-type semiconductor well region 114 forms the transfer channel 103 (FIG. 1). The width of the second n-type semiconductor well region 114 in the X direction is, for example, 250 to 400 [nm]. The depth is, for example, 50 to 100 [nm]. The second n-type semiconductor well region 114 is formed, for example, by implanting arsenic or the like, and the impurity concentration of the implanted arsenic is, for example, 4.0 to 6.0E17 [cm −3 ]. As shown in FIGS. 4B and 5, the transfer electrode 104 exists in a region on the gate insulating film 117 corresponding to the second n-type semiconductor well region 114.
　図５において、第１のｐ型素子分離領域１２３（素子分離領域１０６）と第２のｎ型半導体ウェル領域１１４（転送チャネル１０３）との間のＸ方向の幅は、例えば、２５～１００［ｎｍ］程度である。 In FIG. 5, the width in the X direction between the first p-type element isolation region 123 (element isolation region 106) and the second n-type semiconductor well region 114 (transfer channel 103) is, for example, 25 to 100 [ nm].
　なお、特許文献１に係る固体撮像装置（図１２）においては、仮想線Ｉ９に示すように、光電変換部９０２の下流側の端部が転送電極９０４の下流側の端部と揃っている。一方、本実施形態に係る固体撮像素子（図１）においては、転送電極１０４の下流側他端が光電変換部１０２の下流側他端よりも、ずれ幅ｌｅｎ２だけ上流側へずれている。このことは、図４（ａ），（ｂ）からも同様に見て取れる。 In the solid-state imaging device according to Patent Document 1 (FIG. 12), the downstream end of the photoelectric conversion unit 902 is aligned with the downstream end of the transfer electrode 904 as indicated by a virtual line I9. On the other hand, in the solid-state imaging device according to the present embodiment (FIG. 1), the other downstream end of the transfer electrode 104 is shifted upstream by the shift width len2 from the other downstream end of the photoelectric conversion unit 102. This can also be seen from FIGS. 4A and 4B.
　さらに、特許文献１に係る固体撮像装置（図１２）におけるＤ－Ｄ’断面は、本実施形態に係る固体撮像素子（図１）におけるＣ－Ｃ’断面に対応する。特許文献１に係る固体撮像装置に係るＤ－Ｄ’断面は特に図示しないが、このＤ－Ｄ’断面においては、図５の領域ｂに示すような転送電極１０４が分断された領域は現れない。 Further, the D-D ′ cross section in the solid-state imaging device (FIG. 12) according to Patent Document 1 corresponds to the C-C ′ cross section in the solid-state imaging device (FIG. 1) according to the present embodiment. The DD ′ cross section relating to the solid-state imaging device according to Patent Document 1 is not particularly illustrated, but in this DD ′ cross section, the region where the transfer electrode 104 is divided as shown in the region b of FIG. 5 does not appear. .
　［第１の実施形態の変形例］
　転送電極における端部の傾斜方向は特に限定されない。図６（ａ）に示すように、図１～３に図示した転送電極１０４における端部の傾斜方向とは逆の方向に、転送電極１０４の端部が傾斜していることとしても、上記と同様の効果が得られる。 [Modification of First Embodiment]
The direction of inclination of the end of the transfer electrode is not particularly limited. As shown in FIG. 6A, the end of the transfer electrode 104 may be inclined in a direction opposite to the direction of inclination of the end of the transfer electrode 104 shown in FIGS. Similar effects can be obtained.
　ここで、「Ｙ方向（列方向）において隣接する転送電極の上流側の端部（または下流側の端部）がＸ方向（行方向）に対して傾斜」しているとは、Ｙ方向において隣接する転送電極の上流側の端部において最も上流側の部分と最も下流側の部分を結んだ線分（または下流側の端部において最も上流側の部分と最も下流側の部分を結んだ線分）がＸ方向に対して傾斜していることを指し、転送電極１０４の端部が直線状に形成されていない場合も含まれるものとする。例えば、図６（ｂ）に示すような、転送電極１０４の端部が階段状に形成されている場合も、上記の「Ｙ方向において隣接する転送電極の上流側の端部（または下流側の端部）が行方向に対して傾斜」していることに含まれる。なお、言うまでもなく、階段状に形成されている端部の段数は特に限定されない。また、特に図示しないが、転送電極１０４の端部がＶ字状であっても、上記で説明した効果と同様の効果を得ることが可能である。 Here, “the upstream end (or downstream end) of the adjacent transfer electrode in the Y direction (column direction) is inclined with respect to the X direction (row direction)” means that in the Y direction A line segment connecting the most upstream part and the most downstream part at the upstream end of the adjacent transfer electrode (or a line connecting the most upstream part and the most downstream part at the downstream end. ")" Is inclined with respect to the X direction, and the case where the end of the transfer electrode 104 is not formed in a straight line is also included. For example, as shown in FIG. 6B, even when the end portion of the transfer electrode 104 is formed in a stepped shape, the “upstream end portion (or the downstream end portion of the transfer electrode adjacent in the Y direction” described above. It is included that the “end portion” is inclined with respect to the row direction. Needless to say, the number of steps at the end formed in a staircase shape is not particularly limited. Although not particularly illustrated, even if the end portion of the transfer electrode 104 is V-shaped, the same effect as described above can be obtained.
　［第２の実施形態］
　〈固体撮像装置の構成要素の配置関係〉
　図７は、第２の実施形態に係る固体撮像装置の構成要素の配置関係を模式的に示す図である。第１の実施形態と相違する点は、Ｙ方向において隣接する転送電極２０４の上流側の端部２０４ａと下流側の端部２０４ｂとで挟まれた領域の位置、ならびに、Ｘ方向において隣接する転送電極が金属配線２０５により接続されている点である。 [Second Embodiment]
<Relationship of components of solid-state imaging device>
FIG. 7 is a diagram schematically illustrating the arrangement relationship of the components of the solid-state imaging device according to the second embodiment. The differences from the first embodiment are the position of the region sandwiched between the upstream end portion 204a and the downstream end portion 204b of the transfer electrode 204 adjacent in the Y direction, and the transfer adjacent in the X direction. The electrode is connected by the metal wiring 205.
　図１に示すように、第１の実施形態では、転送電極１０４の端部１０４ａ，１０４ｂで挟まれた領域が、光電変換部１０２の行方向に位置している。一方、本実施形態では、図７に示すように、転送電極２０４の端部２０４ａ，２０４ｂで挟まれた領域が、素子分離領域２０６の行方向に存在する。このような構成にすることで、素子分離領域２０６のポテンシャルが転送チャネル２０３に影響することによる、信号電荷の取り残しを抑制することができる。この詳細については後ほど図８を用いて詳細に説明する。 As shown in FIG. 1, in the first embodiment, the region sandwiched between the end portions 104 a and 104 b of the transfer electrode 104 is located in the row direction of the photoelectric conversion unit 102. On the other hand, in the present embodiment, as shown in FIG. 7, the region sandwiched between the end portions 204 a and 204 b of the transfer electrode 204 exists in the row direction of the element isolation region 206. With such a configuration, it is possible to suppress the remaining of signal charges due to the potential of the element isolation region 206 affecting the transfer channel 203. This will be described in detail later with reference to FIG.
　金属配線２０５は、例えば、タングステン、アルミニウム、銅等の金属材料で形成されている。コンタクト２０８の径は、転送電極２０４のＸ方向の幅よりも小さく設定されており、例えば、２００［ｎｍ］～３５０［ｎｍ］である。また、Ｙ方向において隣接する光電変換部２０２の間に位置する領域における、金属配線２０５のＹ方向の幅ｌｅｎ３は、例えば、１００［ｎｍ］～４００［ｎｍ］である。 The metal wiring 205 is made of, for example, a metal material such as tungsten, aluminum, or copper. The diameter of the contact 208 is set smaller than the width of the transfer electrode 204 in the X direction, and is, for example, 200 [nm] to 350 [nm]. In addition, the width len3 in the Y direction of the metal wiring 205 in the region located between adjacent photoelectric conversion units 202 in the Y direction is, for example, 100 [nm] to 400 [nm].
　上記の金属材料は転送電極２０４を構成するポリシリコンより低抵抗であるため、第１の実施形態の場合と比較して、転送電極２０４に対して、矩形波状の立ち上がりおよび立ち下がりがより急峻な転送電圧を与えることができ、したがって、電荷転送速度を向上させることが可能である。 Since the above metal material has a lower resistance than the polysilicon constituting the transfer electrode 204, the rising and falling of the rectangular wave shape are steeper with respect to the transfer electrode 204 than in the case of the first embodiment. A transfer voltage can be applied, and therefore the charge transfer rate can be improved.
　〈転送チャネルにおけるポテンシャル勾配〉
　次に、転送電極２０４の端部２０４ａ，２０４ｂで挟まれた領域が、素子分離領域２０６の行方向に存在するようにしたことで得られる効果について、図８を用いて説明する。 <Potential gradient in transfer channel>
Next, an effect obtained by causing the region sandwiched between the end portions 204a and 204b of the transfer electrode 204 to exist in the row direction of the element isolation region 206 will be described with reference to FIG.
　図８（ａ）は、第２の実施形態に係る転送チャネル２０３のポテンシャル断面図を転送電極２０４の位置に対応させて示す図である。図８（ｂ）は、第１の実施形態に係る転送チャネル１０３に係るポテンシャル断面図を転送電極１０４の位置に対応させて示す図である。なお、図８各図において、簡略化するために図示を省略した構成要素がある。 FIG. 8A is a diagram showing a potential cross-sectional view of the transfer channel 203 according to the second embodiment in correspondence with the position of the transfer electrode 204. FIG. 8B is a diagram showing a potential cross-sectional view related to the transfer channel 103 according to the first embodiment in association with the position of the transfer electrode 104. In each drawing of FIG. 8, there are components that are not shown for the sake of simplicity.
　先ず、図８（ｂ）を用いて、第１の実施形態に係る場合について説明する。素子分離領域１０６は、隣接する光電変換部１０２を分離するためのものであるため、ポテンシャルは低い。また、この素子分離領域１０６のポテンシャルの影響は、少なからず転送チャネル１０３のポテンシャルにも影響を及ぼすおそれがある。すなわち、ポテンシャル断面図に破線で示したように、転送チャネル１０３における素子分離領域１０６とＸ方向に対応する領域には局部的にポテンシャルが低くなる部分ができてしまう。したがって、信号電荷の転送時には、ポテンシャル断面図に実線で示したように、素子分離領域１０６の影響を受けて、ポテンシャル勾配の傾きが小さくなる裾の領域に局部的にポテンシャルが低くなる部分ができてしまうこととなり、この局部的にポテンシャルが低くなる部分が信号電荷の取り残しを招く恐れがある。また、この局部的にポテンシャルが低くなる部分は、特に微細な画素サイズになるほど顕著になる。 First, the case according to the first embodiment will be described with reference to FIG. The element isolation region 106 is for isolating adjacent photoelectric conversion units 102, and thus has a low potential. In addition, the influence of the potential of the element isolation region 106 may affect the potential of the transfer channel 103 as well. That is, as indicated by a broken line in the potential cross-sectional view, there is a portion where the potential is locally lowered in the region corresponding to the element isolation region 106 and the X direction in the transfer channel 103. Therefore, at the time of signal charge transfer, as shown by the solid line in the potential cross-sectional view, there is a portion where the potential is locally lowered in the bottom region where the gradient of the potential gradient becomes small due to the influence of the element isolation region 106. Therefore, the part where the potential is locally lowered may cause the signal charge to be left behind. Further, the part where the potential is locally lowered becomes more remarkable as the pixel size becomes particularly small.
　次に、図８（ａ）を用いて、本実施形態に係る場合について説明する。第１の実施形態と同様に、光電変換部２０２を分離する素子分離領域２０６の影響を受けて、本実施形態における転送チャネル２０３にも局部的にポテンシャルが低くなる部分ができる。しかしながら、信号電荷の転送時には、ポテンシャル断面図に実線で示したように、素子分離領域２０６の影響による局部的にポテンシャルが低くなる部分が、ポテンシャル勾配の傾きが最大になる中腹付近に位置している。したがって、本実施形態においては、上記の問題は招来しない。 Next, the case according to this embodiment will be described with reference to FIG. Similar to the first embodiment, the transfer channel 203 in this embodiment has a portion where the potential is locally lowered due to the influence of the element isolation region 206 that separates the photoelectric conversion unit 202. However, at the time of signal charge transfer, as indicated by the solid line in the potential cross-sectional view, the part where the potential is locally lowered due to the influence of the element isolation region 206 is located near the middle where the gradient of the potential gradient is maximum. Yes. Therefore, in the present embodiment, the above problem does not occur.
　〈転送電極の端部と他の構成要素との配置関係〉
　次に、上記効果をより効果的に得るための転送電極２０４の端部の位置について、図７を用いて説明する。 <Relationship between transfer electrode end and other components>
Next, the position of the end of the transfer electrode 204 for obtaining the above effect more effectively will be described with reference to FIG.
　図７に示すように、転送チャネル２０３における、転送チャネル２０３の中心をＹ方向に結ぶ仮想線Ｉ２とＹ方向において隣接する素子分離領域２０６の中心をＸ方向に結んだ仮想線Ｉ４とが交差する点（ｏ）に対応する領域は、製造上ポテンシャルが低くなりやすい領域である。一方、転送チャネル２０３における、Ｙ方向において隣接する転送電極２０４の上流側の端部２０４ａと下流側の端部２０４ｂとで挟まれた領域の中心を傾斜方向に結ぶ仮想線Ｉ３を通る領域は、電荷転送時においてポテンシャル勾配の傾きが大きくなる領域である。本実施形態においては、これら三本の全ての仮想線が点（ｏ）で交差するように形成されている。これにより、ポテンシャルが低くなりやすい領域と電荷転送時においてポテンシャル勾配の傾きが最も大きくなる領域とが重なるようになるので、転送チャネルにおいてポテンシャルが低くなっている領域があることによる信号電荷の取り残しを、効率的に防ぐことができる。 As shown in FIG. 7, in the transfer channel 203, a virtual line I2 connecting the center of the transfer channel 203 in the Y direction intersects with a virtual line I4 connecting the center of the element isolation region 206 adjacent in the Y direction in the X direction. The region corresponding to the point (o) is a region where the manufacturing potential tends to be low. On the other hand, in the transfer channel 203, a region passing through a virtual line I3 that connects the center of the region sandwiched between the upstream end portion 204a and the downstream end portion 204b of the transfer electrode 204 adjacent in the Y direction in the inclination direction is This is a region where the gradient of the potential gradient becomes large during charge transfer. In the present embodiment, all three imaginary lines intersect with each other at the point (o). As a result, the region where the potential tends to decrease overlaps with the region where the gradient of the potential gradient becomes the largest during charge transfer, so there is no signal charge left over due to the region where the potential is low in the transfer channel. Can be efficiently prevented.
　なお、上記効果を得るためには、厳密に上記の要件を満たしている必要はない。転送電極２０４の端部２０４ａ，２０４ｂで挟まれた領域が、素子分離領域２０６の行方向に存在している、より好ましくは、転送電極２０４の端部２０４ａ，２０４ｂで挟まれた領域の中心が素子分離領域２０６の行方向に存在していれば、上記の効果を得ることが可能である。 In order to obtain the above effect, it is not necessary to strictly satisfy the above requirements. The region sandwiched between the end portions 204a and 204b of the transfer electrode 204 exists in the row direction of the element isolation region 206. More preferably, the center of the region sandwiched between the end portions 204a and 204b of the transfer electrode 204 is the center. If the element isolation region 206 exists in the row direction, the above effect can be obtained.
　〈転送電極の端部のＸ方向に対する傾斜の角度〉
　転送電極２０４の端部２０４ａ，２０４ｂのＸ方向に対する傾斜角度については、第１の実施形態のような設定範囲内にある必要はなく、傾斜角度の上限は、転送電極２０４の構成に依存して決定されることはない。例えば、図９に示すように、転送電極２０４がＹ方向に２画素以上にわたって形成されていることとしてもよい。なお、図９においては金属配線２０５，２０５ｃの図示は省略した。 <Inclination angle with respect to X direction of end of transfer electrode>
The inclination angle of the end portions 204a and 204b of the transfer electrode 204 with respect to the X direction need not be within the setting range as in the first embodiment, and the upper limit of the inclination angle depends on the configuration of the transfer electrode 204. It will never be decided. For example, as shown in FIG. 9, the transfer electrode 204 may be formed over two or more pixels in the Y direction. In FIG. 9, illustration of the metal wirings 205 and 205c is omitted.
　また、第１の実施形態に係る変形例（図６）を、第２の実施形態およびその変形例に適用することも可能である。 Further, the modification (FIG. 6) according to the first embodiment can be applied to the second embodiment and the modification.
　［第３の実施形態］
　図１０は、第３の実施形態に係る固体撮像装置の構成要素の配置関係を模式的に示す図である。第２の実施形態と相違する点は、金属配線３０５の形状が異なる点である。なお、図１０においては素子分離領域の図示は省略した。 [Third Embodiment]
FIG. 10 is a diagram schematically illustrating the arrangement relationship of the components of the solid-state imaging device according to the third embodiment. The difference from the second embodiment is that the shape of the metal wiring 305 is different. In FIG. 10, the element isolation region is not shown.
　本実施形態における金属配線３０５は、そのＹ方向の幅が光電変換部３０２の列方向の幅よりも大きい。また、金属配線３０５における光電変換部３０２と対向する領域には開口が設けられており、光電変換部３０２への光の入射を遮らないような構成になっている。Ｙ方向において隣接する金属配線３０５の間に相当する領域（隣接する金属配線３０５の間の領域）が、Ｙ方向において隣接する光電変換部３０２の間に存在する。同様に、最終行の転送電極３０４ｃも、金属配線３０５ｃにより互いに接続されている。また、金属配線３０５（または金属配線３０５ｃ）と転送電極３０４（または転送電極３０４ｃ）はコンタクト３０８を介して導通している。 The width of the metal wiring 305 in the present embodiment in the Y direction is larger than the width of the photoelectric conversion unit 302 in the column direction. In addition, an opening is provided in a region of the metal wiring 305 facing the photoelectric conversion unit 302 so that light is not blocked from entering the photoelectric conversion unit 302. A region corresponding to an area between adjacent metal wirings 305 in the Y direction (an area between adjacent metal wirings 305) exists between the photoelectric conversion units 302 adjacent in the Y direction. Similarly, the transfer electrodes 304c in the last row are also connected to each other by a metal wiring 305c. Further, the metal wiring 305 (or the metal wiring 305 c) and the transfer electrode 304 (or the transfer electrode 304 c) are electrically connected through the contact 308.
　Ｙ方向において隣接する金属配線３０５の間に相当する領域のＹ方向の幅ｌｅｎ４（隣接する金属配線３０５の間の距離）は、例えば、１５０［ｎｍ］～３００［ｎｍ］である。また、Ｙ方向において隣接する光電変換部３０２の間の領域における、金属配線３０５のＹ方向の幅ｌｅｎ５は、例えば、１００［ｎｍ］～２００［ｎｍ］である。 The width len4 (distance between adjacent metal wirings 305) in the Y direction of the region corresponding to the space between adjacent metal wirings 305 in the Y direction is, for example, 150 [nm] to 300 [nm]. Further, the width len5 in the Y direction of the metal wiring 305 in the region between the photoelectric conversion units 302 adjacent in the Y direction is, for example, 100 [nm] to 200 [nm].
　上記のような構成にすることで、金属配線３０５のＹ方向の幅を大きくし、金属配線３０５の断面積を拡張することができる。金属配線３０５の抵抗は断面積に反比例するので、金属配線３０５の断面積が拡張した分、金属配線３０５のさらなる低抵抗化が図られる。したがって、転送電極３０４に対して、矩形波状の立ち上がりおよび立ち下がりが急峻な転送電圧を与えることができ、電荷転送速度の向上に貢献できる。 With the above configuration, the width of the metal wiring 305 in the Y direction can be increased, and the cross-sectional area of the metal wiring 305 can be expanded. Since the resistance of the metal wiring 305 is inversely proportional to the cross-sectional area, the resistance of the metal wiring 305 can be further reduced as the cross-sectional area of the metal wiring 305 is expanded. Therefore, a transfer voltage with a steep rising and falling of a rectangular wave shape can be applied to the transfer electrode 304, which can contribute to an improvement in charge transfer speed.
　また、光電変換部３０２と転送チャネル３０３の間に対応する領域上にも金属配線３０５が形成されているため、転送電極３０４に加えて、この領域上にある金属配線３０５に対しても読み出し電圧が印加される。したがって、第１および第２の実施形態と比較して、光電変換部３０２から転送チャネル３０３へ信号電荷が読み出しやすくなるため、転送電極３０４の行方向の幅を縮小できる。その結果、光電変換部３０２の開口面積が拡大でき、固体撮像装置の高感度化を図ることができる。 Further, since the metal wiring 305 is also formed on the corresponding region between the photoelectric conversion unit 302 and the transfer channel 303, the read voltage is applied to the metal wiring 305 on this region in addition to the transfer electrode 304. Is applied. Therefore, compared to the first and second embodiments, signal charges can be easily read from the photoelectric conversion unit 302 to the transfer channel 303, and thus the width of the transfer electrode 304 in the row direction can be reduced. As a result, the opening area of the photoelectric conversion unit 302 can be increased, and the sensitivity of the solid-state imaging device can be increased.
　さらに、金属配線３０５を光電変換部３０２を除く部分に対する遮光膜として機能させることが可能である。これにより、半導体基板における光電変換部３０２以外の領域で光電変換が起こることを防止できるので、その結果、スミアノイズ低減に貢献できる。 Furthermore, the metal wiring 305 can be made to function as a light-shielding film for the portion excluding the photoelectric conversion portion 302. As a result, it is possible to prevent photoelectric conversion from occurring in a region other than the photoelectric conversion unit 302 in the semiconductor substrate, and as a result, it is possible to contribute to reducing smear noise.
　なお、第１の実施形態に係る変形例（図６）を、第３の実施形態に適用することも可能である。 Note that the modification (FIG. 6) according to the first embodiment can also be applied to the third embodiment.
　以上、第１乃至第３の実施形態および変形例について説明したが、本発明はこれらの例に限られない。例えば、下記のような変形例が考えられる。以下、第１の実施形態を例に挙げて説明するが、他の実施形態ならびに変形例でも同様に適用できることは言うまでもない。 As mentioned above, although 1st thru | or 3rd embodiment and the modification were demonstrated, this invention is not limited to these examples. For example, the following modifications can be considered. Hereinafter, the first embodiment will be described as an example, but it goes without saying that other embodiments and modifications can be similarly applied.
　［その他の変形例］
　（１）上記の実施形態においては、転送電極の上流側端部の傾斜と下流側端部の傾斜が等しくなるように形成されていることとしたが、本発明はこれに限られない。上流側の端部が行方向に対して傾斜し、この傾斜に対応して下流側の端部が行方向に対して傾斜していればよく、上流側端部の傾斜と下流側端部の傾斜は異なっていることとしてもよい。しかしながら、上流側端部の傾斜に対応して下流側の端部が傾斜している必要があり、上流側端部の傾斜方向に対して逆の方向に下流側の端部が傾斜している場合は含まないものとする。 [Other variations]
(1) In the above embodiment, the transfer electrode is formed so that the slope of the upstream end and the slope of the downstream end are equal, but the present invention is not limited to this. It is sufficient that the upstream end is inclined with respect to the row direction, and the downstream end is inclined with respect to the row direction corresponding to this inclination. The upstream end and the downstream end are inclined. The inclination may be different. However, the end on the downstream side needs to be inclined corresponding to the inclination of the upstream end, and the downstream end is inclined in a direction opposite to the inclination direction of the upstream end. Cases shall not be included.
　（２）上記の実施形態では、垂直転送チャネルにおける垂直転送電極の端部を傾斜させる例について説明したが、図１１に示すように、水平転送チャネルにおける水平転送電極の端部を傾斜させることしてもよい。 (2) In the above embodiment, the example in which the end of the vertical transfer electrode in the vertical transfer channel is inclined has been described. However, as shown in FIG. 11, the end of the horizontal transfer electrode in the horizontal transfer channel is inclined. Also good.
　図１１は、本変形例に係る固体撮像装置の構成要素の配置関係を模式的に示す図である。光電変換部４０２に蓄積された信号電荷は、転送電極４０４に読み出し電圧が印加されることにより転送チャネル４０３に読み出される。転送方向の下流側終端の転送チャネル４０３まで転送された信号電荷は、最終行の転送電極４０４ｃに所定電圧が印加されることで水平転送チャネル４０７に転送される。水平転送チャネル４０７に転送された信号電荷は、対応する水平転送電極４０９に水平転送用の電圧が印加されることで、水平転送チャネル４０７を転送方向の上流側から下流側へ転送される。このとき、水平転送電極４０９の端部をＹ方向に対して傾斜して形成されている。なお、水平転送チャネル４０７においても、光電変換部４０２からなる光電変換部列一つに対し、一つの水平転送電極４０９を配置した１画素１電極型となっている。 FIG. 11 is a diagram schematically showing the arrangement relationship of the components of the solid-state imaging device according to this modification. The signal charge accumulated in the photoelectric conversion unit 402 is read out to the transfer channel 403 when a read voltage is applied to the transfer electrode 404. The signal charge transferred to the transfer channel 403 at the downstream end in the transfer direction is transferred to the horizontal transfer channel 407 by applying a predetermined voltage to the transfer electrode 404c in the last row. The signal charge transferred to the horizontal transfer channel 407 is transferred from the upstream side to the downstream side in the transfer direction by applying a horizontal transfer voltage to the corresponding horizontal transfer electrode 409. At this time, the end of the horizontal transfer electrode 409 is formed to be inclined with respect to the Y direction. Note that the horizontal transfer channel 407 is also a one-pixel one-electrode type in which one horizontal transfer electrode 409 is arranged for one photoelectric conversion unit row formed of the photoelectric conversion units 402.
　図１１に示すように、転送チャネル４０３のＸ方向の幅と比較すると、水平転送チャネル４０７のＹ方向の幅は大きく、例えば、数［μｍ］～数十［μｍ］である。そのため、水平転送チャネル４０７においては転送チャネル４０３と比較して、信号電荷の取り残しが発生しやすい。さらに、水平転送チャネル４０７においては、通常、例えば３０～５０［ＭＨｚ］程度の高い転送周波数で信号電荷の転送が行われており、信号電荷の取り残しの問題が顕著になる。したがって、水平転送電極４０９の端部を傾斜させることによる電荷転送速度の高速化の効果は大きい。 As shown in FIG. 11, the width of the horizontal transfer channel 407 in the Y direction is larger than the width of the transfer channel 403 in the X direction, for example, several [μm] to several tens [μm]. Therefore, in the horizontal transfer channel 407, signal charges are easily left behind as compared with the transfer channel 403. Further, in the horizontal transfer channel 407, signal charges are normally transferred at a transfer frequency as high as, for example, about 30 to 50 [MHz], and the problem of remaining signal charges becomes significant. Therefore, the effect of increasing the charge transfer rate by tilting the end of the horizontal transfer electrode 409 is significant.
　（３）各図は、本発明が理解できる程度に配置関係を概略的に示してあるに過ぎず、従って、本発明は図示例に限定されるものではない。また、図を分かり易くするために、一部省略した部分がある。 (3) Each drawing only schematically shows the arrangement relationship to the extent that the present invention can be understood, and therefore the present invention is not limited to the illustrated examples. In addition, some parts are omitted for easy understanding of the drawing.
　（４）上記の実施形態における「Ｘ方向に対する傾斜は全ての転送電極で等しい」には、製造誤差等の範囲内での誤差は当然許容されるものとする。 (4) In the above embodiment, “inclination with respect to the X direction is the same for all transfer electrodes”, an error within a range such as a manufacturing error is naturally allowed.
　（５）上記の実施形態においては、信号電荷が電子である場合について説明したが、信号電荷がホールである場合についても、上記実施形態のｎ型とｐ型を入れ替えることで同様の原理で説明できる。 (5) In the above embodiment, the case where the signal charge is an electron has been described. However, the case where the signal charge is a hole is also described by replacing the n-type and the p-type in the above-described embodiment on the same principle. it can.
　（６）ハイレベル，ミドルレベル，ローレベルにより表される論理レベルは、本発明を具体的に説明するために例示するものであり、例示された論理レベルの異なる組み合わせにより、同等の結果を得ることも可能である。 (6) The logical levels represented by the high level, the middle level, and the low level are exemplified to specifically describe the present invention, and equivalent results are obtained by different combinations of the illustrated logical levels. It is also possible.
　（７）上記の実施形態および変形例は単なる好適例に過ぎず、本発明は何らこれに限定されない。本発明の要旨を逸脱しない範囲で、上記実施形態および変形例に挙げた構成を適宜好適に組み合わせたり、上記実施形態等に対して当業者が思いつく範囲内の変更を施した様々な構成がとり得る。また、上記実施形態で挙げた数値や材料等は一例であり、これらに限定されるものではない。 (7) The above embodiments and modifications are merely suitable examples, and the present invention is not limited to these. Without departing from the scope of the present invention, the configurations described in the above embodiments and modifications may be appropriately combined as appropriate, or various configurations may be applied to the above embodiments and the like within the scope conceived by those skilled in the art. obtain. In addition, the numerical values, materials, and the like given in the above embodiment are examples, and the invention is not limited to these.
　本発明は、例えば、高画質が要求されるデジタルスチルカメラおよびデジタルビデオカメラ等の電子機器に好適に利用可能である。 The present invention can be suitably used for electronic devices such as digital still cameras and digital video cameras that require high image quality, for example.
　　１０１ａ　半導体基板
　　１０１ｂ　ｐ型のウェル領域
　　１０２、２０２、３０２、４０２　光電変換部
　　１０３、２０３、３０３、４０３　転送チャネル
　　１０４、２０４、３０４、４０４　転送電極
　　１０４ａ、２０４ａ　転送電極の上流側の端部
　　１０４ｂ、２０４ｂ　転送電極の下流側の端部
　　１０４ｃ、２０４ｃ、３０４ｃ、４０４ｃ　最終行の転送電極
　　１０５　配線
　　２０５、３０５　金属配線
　　２０５ｃ、３０５ｃ　最終行の金属配線
　　１０６、２０６　素子分離領域
　　１０７、４０７　水平転送チャネル
　　２０８、３０８　コンタクト
　　４０９　水平転送電極
　　１１１　第１のｎ型半導体ウェル領域
　　１１２　第１のｐ型半導体ウェル領域
　　１１３　第２のｐ型半導体ウェル領域
　　１１４　第２のｎ型半導体ウェル領域
　　１１５　第２のｐ型素子分離領域
　　１１６　第３のｐ型素子分離領域
　　１１７　ゲート絶縁膜
　　１１８　層間絶縁膜
　　１１９　遮光膜
　　１２０　ＢＰＳＧ膜
　　１２１　カラーフィルタ
　　１２２　トップレンズ
　　１２３　第１のｐ型素子分離領域
　　９０２　フォトダイオード（光電変換部）
　　９０３　垂直ＣＣＤ（転送チャネル）
　　９０４　転送電極
　　９０５　接続部 101a semiconductor substrate 101b p- type well region 102, 202, 302, 402 photoelectric conversion unit 103, 203, 303, 403 transfer channel 104, 204, 304, 404 transfer electrode 104a, 204a upstream end 104b of transfer electrode, 204b Transfer electrode downstream end 104c, 204c, 304c, 404c Last row transfer electrode 105 Wiring 205, 305 Metal wiring 205c, 305c Last row metal wiring 106, 206 Element isolation region 107, 407 Horizontal transfer channel 208, 308 Contact 409 Horizontal transfer electrode 111 First n-type semiconductor well region 112 First p-type semiconductor well region 113 Second p-type semiconductor well region 114 Second n-type semiconductor well region 115 Second p-type element isolation Region 116 3rd P-type element isolation region 117 Gate insulating film 118 Interlayer insulating film 119 Light-shielding film 120 BPSG film 121 Color filter 122 Top lens 123 First p-type element isolation region 902 Photodiode (photoelectric conversion unit)
903 Vertical CCD (transfer channel)
904 Transfer electrode 905 Connection part

Claims (8)

  1. 　半導体基板内に行列状に形成され、入射光を信号電荷に変換する複数の光電変換部と、
    　前記半導体基板内における、隣接する光電変換部の列の間に形成された転送チャネルと、
    　前記半導体基板上における前記転送チャネルに対応する領域に、前記光電変換部と１対１に対応する形態で列方向に複数形成され、対応する光電変換部から信号電荷を読み出して前記転送チャネル内を転送方向の上流側から下流側へ転送させる転送電極と、
    　を備え、
    　前記複数の転送電極を平面視した場合に、列方向において隣接する転送電極の端部のうち上流側の端部が行方向に対して傾斜して形成されるとともに、前記上流側の端部の傾斜に対応してこれと列方向において隣接する転送電極の下流側の端部が行方向に対して傾斜して形成されている
    　ことを特徴とする固体撮像装置。     A plurality of photoelectric conversion units formed in a matrix in a semiconductor substrate and converting incident light into signal charges;
    A transfer channel formed between adjacent rows of photoelectric conversion units in the semiconductor substrate;
    In the region corresponding to the transfer channel on the semiconductor substrate, a plurality of one-to-one forms corresponding to the photoelectric conversion units are formed in the column direction, and signal charges are read from the corresponding photoelectric conversion units to pass through the transfer channel. A transfer electrode for transferring from the upstream side to the downstream side in the transfer direction;
    With
    When the plurality of transfer electrodes are viewed in plan, an end on the upstream side among the ends of the transfer electrodes adjacent in the column direction is formed to be inclined with respect to the row direction, and the end of the upstream side is formed. Corresponding to the inclination, the downstream end of the transfer electrode adjacent in the column direction is formed to be inclined with respect to the row direction.
  2. 　前記固体撮像装置は、さらに、前記半導体基板内に、列方向において隣接する光電変換部を分離する素子分離領域を備え、
    　列方向において隣接する転送電極の前記上流側の端部と前記下流側の端部とで挟まれた領域が、前記素子分離領域の行方向に存在する
    　ことを特徴とする請求項１に記載の固体撮像装置。     The solid-state imaging device further includes, in the semiconductor substrate, an element isolation region that separates adjacent photoelectric conversion units in the column direction,
    The region sandwiched between the upstream end portion and the downstream end portion of the transfer electrodes adjacent in the column direction exists in the row direction of the element isolation region. Solid-state imaging device.
  3. 　列方向において隣接する転送電極の前記上流側の端部と前記下流側の端部とで挟まれた領域の中心が、前記素子分離領域の行方向に存在する
    　ことを特徴とする請求項２に記載の固体撮像装置。     The center of a region sandwiched between the upstream end and the downstream end of the transfer electrodes adjacent in the column direction exists in the row direction of the element isolation region. The solid-state imaging device described.
  4. 　前記固体撮像装置は、さらに、
    　前記複数の転送電極の上方に設けられ、各行に配置されるとともに行方向に延び、かつ、前記複数の転送電極よりも低抵抗な金属配線を備え、
    　前記各行の転送電極は、対応する行の金属配線とコンタクトを介して電気的に接続されている
    　ことを特徴とする請求項１～３のいずれか一項に記載の固体撮像装置。     The solid-state imaging device further includes:
    Provided above the plurality of transfer electrodes, provided in each row and extending in the row direction, and comprising a metal wiring having a lower resistance than the plurality of transfer electrodes,
    The solid-state imaging device according to any one of claims 1 to 3, wherein the transfer electrode of each row is electrically connected to the metal wiring of the corresponding row via a contact.
  5. 　行方向において隣接する転送電極同士が分離されている
    　ことを特徴とする請求項４に記載の固体撮像装置。     The solid-state imaging device according to claim 4, wherein transfer electrodes adjacent in the row direction are separated from each other.
  6. 　前記金属配線の幅が、前記光電変換部の列方向の幅よりも大きく、
    　前記金属配線における前記光電変換部と対向する領域に開口が設けられており、
    　列方向において隣接する金属配線の間に相当する領域が、列方向において隣接する光電変換部の間に存在する
    　ことを特徴とする請求項４または５のいずれか一項に記載の固体撮像装置。     The width of the metal wiring is larger than the width in the column direction of the photoelectric conversion unit,
    An opening is provided in a region facing the photoelectric conversion unit in the metal wiring,
    6. The solid-state imaging device according to claim 4, wherein a region corresponding to between the metal wirings adjacent in the column direction exists between the photoelectric conversion units adjacent in the column direction.
  7. 　前記複数の転送電極における端部の行方向に対する傾斜は、各転送電極で等しい
    　ことを特徴とする請求項１に記載の固体撮像装置。     2. The solid-state imaging device according to claim 1, wherein inclinations of the end portions of the plurality of transfer electrodes with respect to the row direction are the same for each transfer electrode.
  8. 　前記固体撮像装置は、さらに、前記半導体基板内に、列方向において隣接する光電変換部を分離する素子分離領域を備え、
    　列方向において隣接する転送電極の前記上流側の端部と前記下流側の端部とで挟まれた領域の中心を前記傾斜方向に結ぶ仮想線が、
    　前記転送チャネルの中心を列方向に結ぶ仮想線と、列方向において隣接する素子分離領域の中心を行方向に結んだ仮想線と交差する
    　ことを特徴とする請求項７に記載の固体撮像装置。     The solid-state imaging device further includes, in the semiconductor substrate, an element isolation region that separates adjacent photoelectric conversion units in the column direction,
    An imaginary line connecting the center of the region sandwiched between the upstream end and the downstream end of the transfer electrodes adjacent in the column direction in the tilt direction,
    The solid-state imaging device according to claim 7, wherein a virtual line connecting the centers of the transfer channels in the column direction and a virtual line connecting the centers of element isolation regions adjacent in the column direction in the row direction.
PCT/JP2011/004107 2010-12-17 2011-07-21 Solid-state image pickup device WO2012081139A1 (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02159063A (en) * 1988-12-13 1990-06-19 Toshiba Corp Solid-state image-sensing device
JPH0774344A (en) * 1993-09-03 1995-03-17 Sony Corp Charge transfer device
JP2001053266A (en) * 1999-08-13 2001-02-23 Sony Corp Solid-state image pickup element and drive thereof
JP2006319184A (en) * 2005-05-13 2006-11-24 Sony Corp Solid-state imaging device and camera
JP2008053304A (en) * 2006-08-22 2008-03-06 Matsushita Electric Ind Co Ltd Solid-state imaging apparatus
JP2010183107A (en) * 2010-05-10 2010-08-19 Sony Corp Solid-state imaging device and method of manufacturing the same

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02159063A (en) * 1988-12-13 1990-06-19 Toshiba Corp Solid-state image-sensing device
JPH0774344A (en) * 1993-09-03 1995-03-17 Sony Corp Charge transfer device
JP2001053266A (en) * 1999-08-13 2001-02-23 Sony Corp Solid-state image pickup element and drive thereof
JP2006319184A (en) * 2005-05-13 2006-11-24 Sony Corp Solid-state imaging device and camera
JP2008053304A (en) * 2006-08-22 2008-03-06 Matsushita Electric Ind Co Ltd Solid-state imaging apparatus
JP2010183107A (en) * 2010-05-10 2010-08-19 Sony Corp Solid-state imaging device and method of manufacturing the same

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