JPH04262680A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To attain the interchangeability of solid-state image pickup devices whose formats are different by permitting the length of a transfer stage in a connection part between an electric charge detection output amplifier part and an effective horizontal charge transferring part to be longer than that of the effective horizontal charge transferring part. CONSTITUTION:When the measure format of an image pickup area 1 is reduced from 1/2 inch to 1/3 inch, for example, the effective horizontal charge transferring part 6a of a horizontal charge transferring resistor 6 corresponds to a vertical charge transferring resistor 3 and horizontal transfer electrodes are arranged at the intervals of 9.6mum. The horizontal transferring part stage part of the connecting part 6b executes agreement to the number of the transfer stage in the case of 1/2 inch format. Therefore, the length of one transfer stage is set to be 12. 6mum in order to secure about 100mum which is necessary for preventing interference in the chip arrangement of a vertical electrode leading wiring part 4 and the electric charge detection output amplifier part 7. Thus, a same signal system as the large image pickup format drives the solid-state image pickup device even if the image pickup format is permitted to be small by the same image element number.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a solid-state image sensor,
In particular, the present invention relates to an interline transfer type two-dimensional solid-state image sensor.

0002

2. Description of the Related Art FIG. 4 is a schematic plan view of a conventional solid-state image sensing device of this type. As shown in the figure, the imaging area 1 is
It is composed of a plurality of photoelectric conversion photodiodes 2 arranged in a matrix and vertical charge transfer registers 3 corresponding to the number of horizontal pixels. Vertical electrode lead wiring sections 4 and 5 are provided for leading out each electrode of the transfer register and connecting the electrode to, for example, four-phase clock wiring.

These vertical electrode lead wiring sections 4 and 5 are usually provided on both sides of the imaging area so that clocks can be applied from both ends in order to prevent clock signals from becoming dull in the center of the imaging area. be.

On the other hand, the horizontal charge transfer register 6 includes an effective horizontal charge transfer section 6a having the number of stages equal to the number of horizontal pixels for receiving the charges of the vertical charge transfer register 3 of the same number as the number of horizontal pixels in the imaging area; The charge transfer section 6a is composed of about 10 stages of connection sections 6b for connecting the charge transfer section 6a to a charge detection output amplifier section 7 that converts signal charges into electrical signals.

The connection section 6b of this horizontal charge transfer register is configured with the same electrode spacing and electrode dimensions as the effective horizontal charge transfer section 6a, and the number of transfer stages includes the charge detection output amplifier section 7 and the vertical electrode lead-out wiring. The number of stages is selected to ensure a distance that will not interfere with the chip arrangement. Although this interference-free distance depends on the design method of the vertical electrode lead-out wiring section, normally, when the connecting section 6b is formed linearly from the effective horizontal charge transfer section 6a, a distance of about 100 μm is required. Therefore, when the image sensor shown in FIG. 4 has a 1/2 inch format and has 250,000 pixels, if the horizontal pixel interval is 12.7 μm, the number of stages for 8 pixels is required.
In addition, in the case of 1/2 inch format / 380,000 pixels,
If the horizontal pixel interval is 8.4 μm, stages for 12 pixels are required.

[0006]

[Problem to be Solved by the Invention] Under such design conditions, if the number of pixels is different, the horizontal transfer clock frequency is different, so even if the number of stages of the connection section 6b is different, it is necessary to design different clock signal generators. In order to use
No serious problems will occur. However, when reducing the size by changing the imaging format from 1/2 inch format to, for example, 1/3 inch format while keeping the number of pixels constant, the horizontal pixel spacing will naturally become smaller, but the dimensions of the vertical electrode lead wiring section will decrease. Since there is almost no difference, for example, in the case of 1/3 inch format and 250,000 pixels, the horizontal pixel interval is 9.6 μm, and 11 pixels are required to avoid interference. This is an increase of 3 pixels compared to 8 pixels in the conventional 1/2 inch format, and when driven by the same clock signal generator, an image sensor with a 1/3 inch format design has 3 pixels. This causes a problem that the image pickup signal is delayed by 30 minutes, and a serious problem arises in that the design of the drive signal circuit, which does not need to be changed if the number of pixels is the same, has to be changed. That is,
In the conventional example, even if the number of pixels is the same, there is a problem that compatibility cannot be maintained if the imaging format is changed.

[0007]

[Means for Solving the Problems] A solid-state image sensor of the present invention includes a plurality of photoelectric conversion regions arranged two-dimensionally, and receives signal charges photoelectrically converted in the photoelectric conversion regions and transfers them in a vertical direction. a horizontal charge transfer register that receives signal charges transferred by these vertical charge transfer registers and sequentially transfers them horizontally; and a horizontal charge transfer register that receives signal charges sent from the horizontal charge transfer registers. a charge detection output amplifier section that converts the signal into an electrical signal output and outputs the signal; and an effective horizontal charge transfer section in which the horizontal charge transfer register receives signal charge transfer from the vertical charge transfer register;
a connection horizontal charge transfer section provided between the effective horizontal charge transfer section and the charge detection output amplifier section, and charge transfer of each transfer stage of the connection horizontal charge transfer section. It is characterized in that the length in the direction is different from that of each transfer stage of the effective horizontal charge transfer section.

[0008]

Embodiments Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of a first embodiment of the present invention. As shown in the figure, this embodiment includes an imaging area 1 consisting of a plurality of photodiodes 2 for photoelectric conversion and a number of vertical charge transfer registers 3 corresponding to the number of horizontal pixels, and each of the vertical charge transfer registers. Pull out the electrode 4
It is composed of vertical electrode lead wiring sections 4 and 5 for connection to phase clock lines, a two-phase drive type horizontal charge transfer register 6, and a charge detection output amplifier section 7.

The horizontal charge transfer register 6 connects an effective horizontal charge transfer section 6a having the same number of transfer stages as the vertical charge transfer register 3, and between the effective horizontal charge transfer section 6a and the charge detection output amplifier section 7. It is composed of a connecting portion 6b.

The imaging area 1 of the solid-state imaging device of this embodiment is 1
/3 inch format, with 512 pixels arranged at a pixel pitch of 9.6 μm in the horizontal direction and 493 pixels arranged at a pixel pitch of 7.5 μm in the vertical direction.

The effective horizontal charge transfer section 6a of the horizontal charge transfer register corresponds to 512 columns of vertical charge transfer registers, and here, 512 stages of horizontal transfer electrodes are arranged at intervals of 9.6 μm. On the other hand, the connecting portion 6b is provided linearly from the effective horizontal charge transfer portion 6a, and the number of horizontal transfer portions in this portion is 8 to match the number of transfer steps in the conventional 1/2 inch imaging format. This is the number of transfer stages for pixels. Therefore, the length of one transfer stage is set to 12.6 μm to ensure approximately 100 μm, which is necessary to avoid interference between the vertical electrode lead-out wiring section 4 and the charge detection amplifier section 7 in terms of chip arrangement. There is. This dimension is about 30% larger than the length of one transfer stage of the effective horizontal charge transfer section 6a, which is 9.6 μm.

In general, when changing the electrode dimensions in the charge transfer direction, if the electrode area decreases in the transfer direction, there will be a problem that the transfer will not be completed halfway;
If the electrode area increases in the transfer direction, there is no restriction on the amount of transferred charge. Therefore, in the case of the present invention, there is no possibility that charge transfer will be hindered.

FIG. 2 is a sectional view of the horizontal charge transfer register near the boundary between the effective horizontal charge transfer section 6a and the connection section 6b, showing in detail the portion where the electrode length changes. In the figure, 8 is a p-type semiconductor region, 9 is an n-type charge transfer region,
10 is a p-type potential barrier region, 11 is a barrier electrode, 12 is a storage electrode, and 13 and 14 are a barrier portion and a storage portion of a horizontal charge transfer register, respectively.

The horizontal charge transfer register of this embodiment employs a two-phase drive system, and includes two storage electrodes and two barrier electrodes to form a one-stage transfer section.

In this embodiment, each stage of the effective horizontal charge transfer section 6a is composed of two barrier sections 13 of 1.3 .mu.m and two storage sections 14 of 3.5 .mu.m, so the length thereof is 9. ．．
On the other hand, in the connection part, each barrier part 13 and accumulation part 14 are both 30% larger, and are 1.8 μm and 4.6 μm, respectively.
5μm, and the length of one transfer stage is 12.6μm.
It is said that

With the above configuration, a 1/3 inch format image sensor can be realized with the same output timing as in the conventional 1/2 inch format.

FIG. 3 is a cross-sectional view of the horizontal charge transfer register near the boundary between the effective horizontal charge transfer section 6a and the connection section 6b according to the second embodiment of the present invention, showing in detail the part where the electrode length changes. It is a diagram. In this embodiment, the length of the barrier section 13 between the effective horizontal charge transfer section 6a and the connection section 6b is kept constant at 1.3 μm, while the dimension of the storage section 14 of the connection section is By increasing the length by 42% from 5μm to 5μm, the length of one transfer stage was increased from 9.6μm to 12.6μm.
is increasing to.

When the dimensions of the barrier portions are kept constant in this way, the potential modulation of the barrier portions due to the potentials of the storage portions adjacent to these barrier portions does not change much even if the transfer electrode spacing is increased, so that the effective horizontal charge The lowest driving voltage is almost constant between the transfer section 6a and the connection section 6b, and as a result, this embodiment has the advantage that the driving voltage of the horizontal charge transfer section can be lower than that of the embodiment shown in FIG.

[0019]

As explained above, the present invention makes the electrode length of the connection part between the charge detection output amplifier part and the effective horizontal charge transfer part longer than that of the effective horizontal charge transfer part, so that the connection part According to the present invention, it is possible to secure a distance to prevent interference in arrangement between the charge detection output amplifier section and the vertical electrode lead-out wiring section without increasing the number of transfer stages. Even if the imaging format is made smaller, the imaging element can be driven by the same signal system as in a larger imaging format. Therefore, according to the present invention, compatibility between solid-state imaging devices of different formats can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of a first embodiment of the present invention.

FIG. 2 is a partially detailed sectional view of the first embodiment of the invention.

FIG. 3 is a partially detailed sectional view of a second embodiment of the invention.

FIG. 4 is a schematic diagram showing the configuration of a conventional example.

[Explanation of symbols]

1 Imaging area 4, 5 Vertical electrode lead wiring section 6 Horizontal charge transfer register 6a Effective horizontal charge transfer section 6b Connection part 7 Charge detection output amplifier section 8 p-type semiconductor region 9 N-type charge transfer region 11 Barrier electrode 12 Storage electrode 13 Barrier part 14 Accumulation section

Claims (1)

[Claims] 1. A plurality of photoelectric conversion regions arranged two-dimensionally, a plurality of vertical charge transfer registers that receive signal charges photoelectrically converted in the photoelectric conversion regions and transfer them in a vertical direction, and A horizontal charge transfer register that receives the signal charge transferred by the transfer register and sequentially transfers it horizontally, and a charge detection output that converts the signal charge sent from the horizontal charge transfer register into an electrical signal output and outputs it. an amplifier section, wherein the horizontal charge transfer register receives signal charge transfer from the vertical charge transfer register; an effective horizontal charge transfer section between the effective horizontal charge transfer section and the charge detection output amplifier section; In a solid-state imaging device, the length in the charge transfer direction of each transfer stage of the connection horizontal charge transfer section is equal to the length of each transfer stage of the effective horizontal charge transfer section. A solid-state imaging device characterized by being different from that of.