JPH04343272A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To enable a solid-state image pickup device to operate at a high speed by a method wherein a drive pulse is applied to the transfer electrode of a vertical register through the intermediary of a metal wiring for every two horizontal pixels. CONSTITUTION:The first transfer electrodes 103-105 formed of the first polycrystalline silicon film to which the same drive pulse is applied are connected in common through the intermediary of a contact section 109 with the first metal wiring layers 111-115 arranged along the transfer channel 102 of a vertical register. On the other hand, the second transfer electrodes 106-108 of the second polycrystalline silicon film are connected to the second metal wiring layers 116-119 arranged vertical to the first metal wiring layers through the intermediary of a contact section 110 provided to the gap of the first metal wiring layers. By this setup, as the same pulse is applied for every two pixels in the horizontal direction, a high speed operation is limited by the resistance of transfer electrodes for two pixels, and as a result, a solid-state image sensing device of his design can operate at a high speed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state imaging device, and more particularly to an interline transfer type or frame interline transfer type CCD imaging device.

0002

2. Description of the Related Art FIG. 3 is a plan view showing an example of the configuration of transfer electrodes of a vertical register in an interline transfer type CCD imaging device according to the prior art. A first transfer electrode 303 made of a first layer of polycrystalline silicon film and a second transfer electrode 306 made of a second layer of polycrystalline silicon film have a comb-shaped shape in which the photoelectric conversion element 301 is cut out. arranged alternately. Driving pulses are normally applied from both ends of the transfer electrodes 303-308. The sheet resistance of polycrystalline silicon films, which are commonly used as materials for transfer electrodes, is several 1.
It has a high resistance of 0Ω, and for example, in a 2 million pixel CCD image sensor adapted to a 1-inch optical system compatible with HDTV, the resistance value from the edge to the center of one transfer electrode is 100Ω.
It will be about kΩ. On the other hand, the capacitance between the substrate and the substrate is 10p.
F, and the time constant due to the product of these resistances and capacitances reaches 1 μs. As a result, the pulse transfer characteristics are significantly deteriorated, causing deterioration in transfer efficiency and reduction in the amount of transferred signals, especially in pixels in the center, and limiting high-speed operation.

FIG. 4 is a plan view showing another example of the configuration of transfer electrodes of a vertical register in an interline transfer type CCD imaging device according to the prior art. In this example, transfer electrodes (403 and 405, 406 and 4
08) are commonly connected. By applying a driving pulse directly from the metal wiring layer to the transfer electrode inside the pixel via the contact portion 409, the effective resistance of the transfer electrode is reduced and the pulse transfer characteristics are improved. In comparison, it achieves high-speed operation of nearly 1MHz.

0004

In the example shown in FIG. 4, a four-phase drive vertical register is assumed, and the same drive pulse is applied to the metal wiring layer for every four pixels in the horizontal direction. Therefore, the contact portion of one transfer electrode also repeats four pixels in the horizontal direction, and high-speed operation is limited by the resistance of the transfer electrode for four pixels.

SUMMARY OF THE INVENTION An object of the present invention is to provide a new charge transfer imaging device that eliminates the drawbacks of the prior art as described above.

[0006]

[Means for Solving the Problems] The present invention provides a photoelectric conversion element column and a vertical transfer electrode arranged in parallel with the photoelectric conversion element column and having a first transfer electrode and a second transfer electrode corresponding to the photoelectric conversion element, respectively. In a solid-state imaging device having a semiconductor chip in which a plurality of pixel columns each consisting of a register are arranged in parallel, the vertical register is arranged along the transfer direction through an insulating film having a predetermined opening, and the same driving pulse is applied to the vertical register. a first metal wiring layer that commonly connects the first transfer electrodes; and a second metal wiring layer that is perpendicular to the first metal wiring layer and connected to the second transfer electrode. There is.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a plan view showing an embodiment of the configuration of transfer electrodes of a vertical register in an interline transfer type CCD imaging device according to an embodiment of the present invention. In this example, the first transfer electrodes 103 to 105 made of the first layer of polycrystalline silicon film to which the same driving pulse is applied are arranged along the transfer channel 102 of the vertical register as in the conventional example of FIG. They are commonly connected via a contact portion 109 by the arranged first metal wiring layers 111 to 115. On the other hand, 2
A second transfer electrode 106 made of a layered polycrystalline silicon film
108 are connected to second metal wiring layers 116 to 119 arranged orthogonally to the first metal wiring layer through contact portions 110 provided in gaps between the first metal wiring layers. ing. This example also assumes a four-phase drive vertical register, but since the same drive pulse is applied to every two pixels in the horizontal direction, high-speed operation is limited by the resistance of the transfer electrode for two pixels. , 2MH compared to the conventional example in Fig. 4
It becomes possible to realize even higher speed operation at speeds higher than z. In the example shown in Fig. 1, a contact portion is also provided for the second transfer electrode every two pixels to connect it to the second metal wiring layer, but as is clear from the figure, a contact portion is provided for each pixel. It is also possible to provide a section and connect it to the second metal wiring layer.

FIG. 2 is a plan view showing the configuration of vertical transfer electrodes in an interline transfer type CCD imaging device according to a second embodiment of the present invention. In this embodiment as well, the first transfer electrodes 203 to 205 in the first layer are formed on a first metal wiring layer arranged along the transfer direction on the transfer channel 202 of the vertical register, as in the first embodiment. 211 to 215 are shared by every two pixels in the horizontal direction via the contact portion 209. On the other hand, the second transfer electrode 206 in the second layer
-208 are openings 21 provided in the first metal wiring layer.
A second metal wiring layer 217 is disposed perpendicularly to the first metal wiring layer via a contact portion 210 in 6.
~220. In this embodiment as well, since a drive pulse is applied to every two pixels in the horizontal direction, high-speed operation is limited by the resistance of the transfer electrode for two pixels, and the operating frequency is approximately 2 MHz compared to the conventional example shown in FIG. This makes it possible to achieve even higher speed operation. Further, as in the first embodiment, it is also possible to provide a contact portion for each pixel to the second transfer electrode and connect it to the second metal wiring layer. Further, in this embodiment, the contact portion 210 is provided at a three-dimensional intersection between the first and second metal wiring layers, and as in the first embodiment, the contact portion 210 is provided at a three-dimensional intersection between the first and second metal wiring layers. Since there is no need to provide a contact part connecting the layer and the second transfer electrode, the width of the second transfer electrode in this part can be made narrower than that in the first embodiment, which reduces the aperture ratio. It becomes possible to increase the sensitivity and improve the sensitivity.

In the two embodiments described above, an example of an interline transfer type CCD imaging device was shown, but it goes without saying that the present invention can be applied to a frame interline type CCD imaging device that requires higher speed operation.

0010

As described above, in the charge transfer imaging device of the present invention, driving pulses are applied to the transfer electrodes constituting the vertical register every two pixels in the horizontal direction via metal wiring, thereby improving the charge transfer imaging device of the present invention. It is possible to achieve higher-speed operation compared to other methods.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a vertical register in an interline transfer type CCD imaging device showing a first embodiment of the present invention.

FIG. 2 is a plan view of a vertical register in an interline transfer type CCD imaging device showing a second embodiment of the present invention.

FIG. 3 is a plan view of a vertical register in an interline transfer type CCD imaging device showing a conventional example.

[Fig. 4] Interline transfer type CCD showing another conventional example
FIG. 3 is a plan view of a vertical register in the imaging device.

[Explanation of symbols]

101, 201, 301, 401 photoelectric conversion element 10
2, 202, 302, 402 Vertical register transfer channels 103-105, 203-205, 303-305, 4
03-405 First vertical transfer electrodes 106-108, 206-208, 306-308, 4
06-408 Second vertical transfer electrode 109, 110, 209, 210 Contact part 11
1 to 115, 211 to 215 Openings in first metal wiring layer 116 to 119, 217 to 220 Second metal wiring layer 410 to 414 Metal wiring layer

Claims (2)

[Claims] 1. A photoelectric conversion element array and a first photoelectric conversion element arranged in parallel with the photoelectric conversion element array and each of the photoelectric conversion elements.
In a solid-state imaging device having a semiconductor chip in which a plurality of pixel columns each consisting of a vertical register in which a transfer electrode and a second transfer electrode are arranged in parallel, an insulating film having a predetermined opening is formed on the vertical register. a first metal wiring layer that commonly connects the first transfer electrodes arranged along the transfer direction and to which the same drive pulse is applied; and a first metal wiring layer that is perpendicular to the first metal wiring layer and that connects the second transfer electrode A solid-state imaging device comprising: a second metal wiring layer connected to the solid-state imaging device; 2. The solid-state imaging device according to claim 1, wherein the second metal wiring layer is connected to the second transfer electrode at a portion where the second metal wiring layer three-dimensionally intersects with the first metal wiring layer.