JPH0697412A - Solid-state image sensing device - Google Patents

Abstract

PURPOSE:To make it possible to secure enough time in any part no matter where it might be and enhance allocation efficiency and prevent the generation of vertical stripes on an image-sensed plane in an allocation transfer of electric charges to first and second horizontal CCD resistor channels from a vertical CCD resistor channel. CONSTITUTION:Each of horizontal transfer electrodes 9o and 9e are separated into first electrode portions 10a and 11a formed in an upper part area of a first horizontal CCD channel 1 and second electrode portions 10b and 11b formed in a second horizontal CCD resistor channel 2. First group and second group horizontal bus lines 12a, 12b, 12c and 12d which feed pulses to the horizontal electrodes are formed on each of the channel areas for the first and second CCD resistors in such a fashion that they may cross the first and second electrode portions respectively. Bus lines 15 and 16 are formed on the upper part of a transfer electrode 7 between the horizontal resistors and the upper part of a vertical and horizontal transfer electrode 8 respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device having a horizontal CCD register having a two-channel structure, and more particularly, a charge of a channel of a vertical CCD register to a channel of a first horizontal CCD register and a channel of a second horizontal CCD register. The present invention relates to the improvement of the charge transfer section that transfers and transfers the data to

[0002]

2. Description of the Related Art FIG. 4 is a plan view of a register portion of an example of a conventional solid-state image pickup device having a horizontal CCD register having a two-channel structure. For example, in the case of the interline transfer type, there is an imaging area by a photodiode above the illustrated portion, and in the case of the frame interline transfer type, there is an accumulation area above the illustrated portion and an imaging area above it. Exists. The channel 101 of the first horizontal CCD register and the channel 102 of the second horizontal CCD register are connected via an oblique intermediate channel 105 between the channel stoppers 103 and 104. Further, the channel 101 of the first horizontal CCD register is connected to the channel 106o of the vertical CCD register in the odd column and the channel 106e of the vertical CCD register in the even column.

Between the channels 101 and 102 of the first and second horizontal CCD registers, the channel 101 of the first horizontal CCD register to the channel 1 of the second horizontal CCD register.
Transfer electrode 107 between horizontal registers for transferring electric charge to 02
Is formed of a polysilicon film. Further, in the upper region of the channels 106o and 106e of the vertical register, there is provided a vertical / horizontal register transfer electrode 108 which extends horizontally across the channels to transfer the charge of the channel to the channel 101 of the first horizontal CCD register. Similarly, it is formed of a polysilicon film. Further, horizontal transfer electrodes 109o and 109e extending in the vertical direction are provided in parallel corresponding to the channels 106o and 106e of each vertical CCD register. Each horizontal transfer electrode is composed of two electrodes made of a polysilicon film, that is, a storage electrode 110a and a barrier electrode 110b. Note that these electrodes 110a
An insulating film is interposed between the overlapping portions of 110b.

On the other hand, in the region 100 where the thick silicon oxide film is formed outside the regions of the channels 101 and 102 of the first and second horizontal CCD registers, the first and second horizontal buses extending horizontally. Lines 111 and 112 are provided. These horizontal bus lines 111 and 112 are generally formed of an aluminum film.

Storage electrode 110a and barrier electrode 1
The polysilicon film forming 10b is formed in a step subsequent to the polysilicon film forming the vertical / horizontal register transfer electrode 108 and the polysilicon film forming the horizontal register transfer electrode 107, and the storage electrode 110a and the barrier film are formed. The electrode 110b is formed from one side edge of the upper region of the vertical / horizontal register transfer electrode 108 to the upper region of the channel 101 of the first horizontal CCD register, the upper region of the horizontal register transfer electrode 107, and the second horizontal CCD register. It extends beyond the upper region of the channel 102 to the region 100 and straddles the upper region of the horizontal register transfer electrode 107. The storage electrode 110a and the barrier electrode 110b of the horizontal transfer electrode 109o are connected to the contact 113.
The storage electrode 110a of the horizontal transfer electrode 109o is connected to the first horizontal bus line 111 by a 113b.
Similarly, the barrier electrode 110b is the second horizontal bus line 1
It is connected to 12.

In such a solid-state image pickup device, the vertical / horizontal register transfer electrode 108 and the horizontal register transfer electrode 107 are connected to a bus line (not shown) at both left and right ends thereof, and pulse voltages are applied from both left and right ends thereof. Is applied. Then, within the horizontal blanking period, for example, the channels 10 of the vertical CCD registers in odd columns
The charge 114 in 6o is transferred to the channel 101 of the first horizontal CCD register, and the charge 115 in the channel 106e of the vertical CCD register in the even column is transferred to the channel 102 of the second horizontal CCD register.

FIG. 5 shows transfer electrodes 108, 109o, 10
9e shows the pulse waveform in the horizontal blanking period in the central portion of the length direction of 107. Since a pulse voltage is applied to the vertical / horizontal register transfer electrode 108 and the horizontal register transfer electrode 107 that extend horizontally for a long time from the left and right ends thereof, the pulse waveform is attenuated at the center of the electrode and its rising and falling edges are reduced. Be slow.
In the figure, in the period T1, the pulse voltage at the vertical / horizontal register transfer electrode 108 becomes 90% or more of the output voltage of the voltage supply source, and moreover, from the first / second horizontal bus lines 111/112 to the horizontal transfer electrode. 109o / 109e
This is a period in which both pulses applied to are at "H". In the period T2, the vertical / horizontal register transfer electrode 1
The pulse voltage at 08 is 1 of the output voltage of the voltage supply source.
0% or less, and the first and second horizontal bus lines 11
Both the pulses applied from 1.112 to the horizontal transfer electrodes 109o and 109e are "L", and the pulse voltage of the horizontal register transfer electrode 107 is 90% or more of the output voltage of the voltage supply source. It is a period. Period T3
The pulse voltage at the vertical / horizontal register transfer electrode 108 is 10% or less of the output voltage of the voltage supply source,
This is a period in which the pulse applied to the horizontal transfer electrode connected to the horizontal bus line 111 is “H” and the pulse applied to the horizontal transfer electrode connected to the second horizontal bus line 112 is “L”.

In the period T1, the charges 114 and 115 in the channels 106o and 106e of each vertical CCD register are transferred to the channel 101 of the first horizontal CCD register.
In the next period T2, the charge 115 in the channel 101 of the first horizontal CCD register is transferred to the horizontal register transfer electrode 107.
The charges 115 of the lower channel are transferred to the lower channel, and in the period T3, the charges 115 of the lower channel of the horizontal register transfer electrode 107 are secondly transferred.
It is transferred to the channel of the horizontal CCD register 102. However, the channels 106o of the vertical CCD registers in odd columns
The charge 114 from 1 remains in the channel 101 of the first horizontal CCD register during the periods T2 and T3.

In the conventional example shown in FIG. 4, the two horizontal bus lines 111 and 112 are provided outside the regions of the channels 101 and 102 of the first and second horizontal CCD registers. In the solid-state imaging device disclosed in Japanese Patent Laid-Open No. 133963, the first horizontal bus line is divided into the upper region of the channel of the first horizontal CCD register, and the second horizontal bus line is divided into the upper region of the channel of the second horizontal CCD register. Has been formed. FIG. 6 is a schematic cross-sectional view showing the relationship,
The first horizontal bus line 111 is formed above the channel 101 of the first horizontal CCD register and above the horizontal transfer electrode group 109, and the second horizontal bus line 112 is formed of the channel of the second horizontal CCD register. In the upper region of 102, it is similarly formed above the horizontal transfer electrode group 109. Each horizontal transfer electrode 109 straddles over the inter-horizontal-register transfer electrode 107 as in the conventional example shown in FIG.
Between the upper regions of the. In FIG. 6, the connection configuration between the horizontal bus lines 111 and 112 and the horizontal transfer electrode 109 is omitted.

[0010]

In any of the conventional solid-state image pickup devices, as described above, each horizontal transfer electrode straddles the transfer electrode between the horizontal registers, and both the first and second horizontal transfer electrodes are provided. It is formed in series between the upper regions of the channels of the CCD register and is shared by the channels of both horizontal CCD registers. Therefore, even if a bus line for supplying a pulse to the horizontal inter-register transfer electrode is formed in the upper region of the horizontal inter-register transfer electrode and it is attempted to connect with this, it is difficult because of the horizontal transfer electrode. There is no choice but to connect bus lines to the left and right ends of the transfer electrodes between horizontal registers and apply the pulse voltage from both ends. Then,
Since the transfer electrode between horizontal registers is formed of a polysilicon film, the resistance from the end portion to the central portion of the electrode is large, and the pulse waveform is attenuated at the central portion of the electrode and the rising and falling edges thereof are reduced as described above. Be slow. As a result, during the horizontal blanking period, the vertical CCD
When the charge is distributed and transferred from the register channel to the first and second horizontal CCD register channels, each transfer period contributing to the operation is reduced, that is, it becomes impossible to secure a sufficient time for transferring the charge, and There is a problem that a sorting failure occurs and appears as so-called vertical streak noise on a captured image.

An object of the present invention is to solve such a problem, that is, in charge transfer from the channels of the vertical CCD register to the channels of the first and second horizontal CCD registers, any portion of the transfer period can be used. A sufficient time can be secured to improve the charge distribution efficiency and prevent the generation of vertical stripe noise on the imaged screen.

[0012]

In the solid-state image pickup device according to the present invention, charges from the channels of each vertical CCD register are distributed and transferred to the channels of the first horizontal CCD register and the channels of the second horizontal CCD register, and in the horizontal direction. Each horizontal transfer electrode for transferring to the first horizontal CC
The first electrode portion formed in the upper region of the channel of the D register and the second electrode portion formed in the upper region of the channel of the second horizontal CCD register are separately formed. Further, the horizontal bus lines for the first group and the second group, which apply pulses to the horizontal transfer electrodes by dividing them into the first group and the second group,
It is formed on each channel region of the first and second horizontal CCD registers so as to cross over the first electrode portion and the second electrode portion of the horizontal transfer electrode.

In a preferred embodiment of the present invention, two horizontal bus lines for the first group and two horizontal buses for the second group are formed on each channel region of the first and second horizontal CCD registers, and the horizontal bus lines for each channel are horizontal. The transfer electrodes are alternately connected.

A bus line for supplying a pulse to the transfer electrode between horizontal registers is formed in parallel with the transfer electrode between the horizontal registers in an upper region of the transfer electrode and connected to the bus line.

Further, a bus line for supplying a pulse to the vertical / horizontal register transfer electrode is formed in parallel with the upper area of the vertical / horizontal register transfer electrode and connected to the bus line.

[0016]

According to such a structure, the horizontal transfer electrodes do not straddle the upper region of the horizontal inter-register transfer electrodes, so that the horizontal inter-register transfer electrodes can be easily connected to the bus line in the upper region. Can be connected.
Actually, a bus line for supplying a pulse to the horizontal inter-register transfer electrode can be formed along the upper inter-horizontal register transfer electrode along the line, and can be connected anywhere in the length direction. The same applies to the vertical / horizontal register transfer electrode and the bus line for supplying a pulse thereto.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a register portion of a solid-state imaging device according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view thereof. In FIG. 1, for example, in the case of the interline transfer type, there is an image pickup region by a photodiode above the illustrated portion, and in the case of the frame interline transfer type, a storage region is formed on the upper portion of the illustrated portion and further above it. There is an imaging area.

The channel 1 of the first horizontal CCD register and the channel 2 of the second horizontal CCD register are connected via a vertical intermediate channel 5 between the channel stoppers 3 and 4. The channel 1 of the first horizontal CCD register is connected to the channel 6o of the vertical CCD register in the odd column and the channel 6e of the vertical CCD register in the even column.

Channel 1 of the first horizontal CCD register is placed between channels 1 and 2 of the first and second horizontal CCD registers.
The inter-horizontal-register transfer electrode 7 that transfers the electric charges from the second horizontal CCD register to the channel 2 of the second horizontal CCD register is formed of a polysilicon film. Also, vertical register channel 6o
・ On the upper part of 6e, the charge of the channel is extended horizontally by intersecting these, and the charge of the channel is set to the channel 1 of the first horizontal CCD register.
Similarly, the vertical / horizontal register transfer electrode 8 for transferring to is formed of a polysilicon film.

Channels 6o and 6 of each vertical CCD register
Horizontal transfer electrodes 9o and 9 arranged in parallel corresponding to e
e is separated into an electrode portion corresponding to channel 1 of the first horizontal CCD register and an electrode portion corresponding to channel 2 of the second horizontal CCD register. That is, each of the horizontal transfer electrodes 9o and 9e is connected to the first storage electrode 10 formed in the upper region of the channel 1 of the first horizontal CCD register.
a and the first barrier electrode 11a, and the second storage electrode 10b and the second barrier electrode 11b formed in the upper region of the channel 2 of the second horizontal CCD register. A set of four electrodes 10a, 10b, 11a, 1
Each of 1b has a polysilicon film, which is formed in a later step than the polysilicon film forming the vertical / horizontal register transfer electrode 8 and the polysilicon film forming the horizontal register transfer electrode 7. The first storage electrode 10a and the first barrier electrode 11a are located between one horizontal edge portion of the upper area of the vertical / horizontal register transfer electrode 8 and over the upper area of the channel 1 of the first horizontal CCD register, and between the horizontal registers. It does not straddle the upper region of the transfer electrode 7 and is interrupted at its peripheral portion. In addition, the second storage electrode 1
0b and the second barrier electrode 11b extend from one side edge of the upper region of the horizontal inter-register transfer electrode 7 to a position beyond the upper region of the channel 2 of the second horizontal CCD register. An insulating film is interposed between the portions where the first storage electrode 10a and the first barrier electrode 11a and the second storage electrode 10b and the second barrier electrode 11b overlap.

In the upper area of the channel 1 of the first horizontal CCD register, the first storage electrodes 1 arranged alternately are arranged.
0a and the first and second barrier electrodes 11a, the first and second two horizontal bus lines 12a extending horizontally so as to cross the upper part of the first barrier electrode 11a.
12b is provided, and in the upper region of the channel 2 of the second horizontal CCD register, a third and third horizontally extending crossing upper portions of the alternately arranged second storage electrodes 10a and second barrier electrodes 11a. Two horizontal bus lines 12c and 12d of 4 are provided. These horizontal bus lines 12a, 12b, 12c, 12d are formed of a metal film such as an aluminum film or a tungsten film in a process subsequent to the polysilicon film forming the storage electrodes 10a, 10b and the barrier electrodes 11a, 11b. .

First storage electrode 1 of horizontal transfer electrode 9o
0a and the first barrier electrode 11a are contact 13a.
14a is connected to the first horizontal bus line 12a,
The first storage electrode 10a and the first of the horizontal transfer electrode 9e
The barrier electrode 11a is connected to the second horizontal bus line 12b by the contacts 13b and 14b, and is connected to the second storage electrode 10b and the second barrier electrode 1 of the horizontal transfer electrode 9o.
1b is connected to the third horizontal bus line 12c by the contacts 13c and 14c, and the second storage electrode 10b and the first barrier electrode 11b of the horizontal transfer electrode 9e are connected to the fourth horizontal bus line 12 by the contacts 13d and 14d.
connected to d.

On the other hand, a bus line 15 for supplying a pulse to the horizontal inter-register transfer electrode 7 is provided in an upper region of the horizontal inter-register transfer electrode 7.
Is provided parallel to the vertical / horizontal register transfer electrode 8 in the upper region of the vertical / horizontal register transfer electrode 8.
A bus line 16 for supplying a pulse is provided parallel to the vertical / horizontal register transfer electrode 8. These bus lines 15 and 16 also have a metal film such as an aluminum film or a tungsten film, and have storage electrodes 10a and 10
b and the barrier electrodes 11a and 11b are formed in a later step than the polysilicon film.

The bus line 15 is provided for each channel stopper 3
The horizontal register transfer electrode 7 and the contact 17 are connected at a position corresponding to 4. Also, bus line 1
6 is connected by a contact 18 to a vertical / horizontal register transfer electrode 8 at a position corresponding to each of the channels 6o and 6e of each vertical CCD register.

FIG. 3 shows a pulse waveform in the horizontal blanking period in the central portion of the transfer electrodes 8 · 9o · 9e · 7 in the longitudinal direction. The vertical / horizontal register transfer electrode 8 extending horizontally is connected to the bus line 16 formed in the upper region thereof everywhere, and the horizontal register transfer electrode 7 also extending horizontally is formed in the upper region thereof. Since it is connected to the bus line 16 everywhere, the applied pulse waveform is hardly attenuated at any part of the electrode. In the same figure, in the period T1, the pulse voltage at the vertical / horizontal register transfer electrode 8 is 90% or more of the output voltage of the voltage supply source, and moreover, from the first horizontal bus line 12a and the third horizontal bus line 12c. This is a period in which the pulse applied to the transfer electrodes 9o and 9e and the pulse applied to the horizontal transfer electrodes 9o and 9e from the second horizontal bus line 12b and the fourth horizontal bus line 12d are both "H". . In the period T2, the pulse voltage at the vertical / horizontal register transfer electrode 8 becomes 10% or less of the output voltage of the voltage supply source, and moreover, from the first horizontal bus line 12a and the third horizontal bus line 12c to the horizontal transfer electrode 9o. Both the pulse applied to 9e and the pulse applied to the horizontal transfer electrodes 9o and 9e from the second horizontal bus line 12b and the fourth horizontal bus line 12d become "L", and the horizontal register transfer electrode 7 This is a period in which the pulse voltage is 90% or more of the output voltage of the voltage supply source. In the period T3, when the pulse voltage at the vertical / horizontal register transfer electrode 8 is 10% or less of the output voltage of the voltage supply source, the horizontal transfer electrodes 9o and 9e are transferred from the first horizontal bus line 12a and the third horizontal bus line 12c. This is a period in which the applied pulse is "H" and the pulse applied from the second horizontal bus line 12b and the fourth horizontal bus line 12d to the horizontal transfer electrodes 9o and 9e is "L".

In the period T1, the charges in the channels 6o and 6e of each vertical CCD register are transferred to the channel 1 of the first horizontal CCD register. In the next period T2, from the channel 6e of the vertical CCD register in the even column to the first horizontal CCD
The charge transferred to the channel 1 of the register is the channel 1
Is transferred to the channel below the horizontal inter-register transfer electrode 7, and during the period T3, the charge in the channel below the horizontal inter-register transfer electrode 7 is transferred to the channel of the second horizontal CCD register 2. However, the charges from the channels 6o of the odd column vertical CCD registers remain in the channel 1 of the first horizontal CCD register during the periods T2 and T3.

As described above, the vertical / horizontal register transfer electrode 8 is connected to the bus line 16 above it everywhere, and the horizontal register transfer electrode 7 is connected to the bus line 15 above it everywhere. Therefore, for all of these transfer electrodes, as shown in FIG.
The pulse voltage from 6/15 is applied to the central part of the electrode with almost no deformation, so that each transfer period T1 / T2
A sufficient time for charge transfer can be secured for T3.

[0028]

According to the present invention, each horizontal transfer electrode is formed in the first electrode portion formed in the upper region of the channel of the first horizontal CCD register and in the upper region of the channel of the second horizontal CCD register. The second inter-register transfer electrodes are formed separately from the second inter-register transfer electrodes so that each horizontal transfer electrode does not straddle the upper region of the horizontal inter-register transfer electrodes. Can be easily connected to the bus line. The same applies to the transfer electrodes between the vertical and horizontal registers. Therefore, the vertical CC
In charge transfer transfer from the D register channel to the first and second horizontal CCD register channels, sufficient time can be secured at any part of the transfer period, so the charge distribution efficiency is improved, and on the imaged screen. It is possible to prevent vertical streak noise from occurring.

[Brief description of drawings]

FIG. 1 is a plan view of a register portion of a solid-state imaging device according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of the above.

FIG. 3 is a timing chart showing a pulse waveform in a horizontal blanking period in a central portion of each transfer electrode in the length direction in the solid-state imaging device.

FIG. 4 is a plan view of a register portion of an example of a conventional solid-state imaging device having a horizontal CCD register having a 2-channel structure.

FIG. 5 is a timing chart showing a pulse waveform in a horizontal blanking period in a central portion of each transfer electrode in the length direction of the solid-state imaging device.

FIG. 6 is a schematic cross-sectional view of another conventional example.

[Explanation of symbols]

1 Channel of 1st horizontal CCD register 2 Channel of 2nd horizontal CCD register 6o Channel of vertical CCD register of odd column 6e Channel of vertical CCD register of even column 7 Transfer electrode between horizontal registers 8 Transfer electrode between vertical and horizontal registers 9o 9e Horizontal transfer electrode 10a, 10b Storage electrode 11a, 11b Barrier electrode 12a, 12b, 12c, 12d Horizontal bus line 13a, 13b, 13c, 13d Contact 14a, 14b, 14c, 14d Contact 15 Bus for transfer electrode between horizontal registers Line 16 Bus line for transfer electrodes between vertical and horizontal registers

Claims (4)

[Claims] 1. A plurality of photodiodes arranged, a multi-channel vertical CCD register for receiving charges from the photodiodes, first and second horizontal CCD registers having a two-channel structure, and a channel of the vertical CCD register. Extending in a direction intersecting with the charge of the channel
A vertical / horizontal register transfer electrode for transferring to the channel of the horizontal CCD register, and a second electrode extending horizontally from the channel of the first horizontal CCD register to the channel of the second horizontal CCD register. An inter-horizontal-register transfer electrode for transferring charges to the channels of the horizontal CCD registers, and to transfer charges from the channels of the vertical CCD registers to the channels of the first horizontal CCD registers and the channels of the second horizontal CCD registers, and A horizontal transfer electrode provided corresponding to each channel of the vertical CCD register for performing transfer in the horizontal direction, and a first group for applying a pulse to the horizontal transfer electrode separately into a first group and a second group And a horizontal bus line for the second group, each of the horizontal transfer electrodes includes the first horizontal CC. The first electrode portion formed in the upper region of the channel of the register and the second electrode portion formed in the upper region of the channel of the second horizontal CCD register are separated into the first group and the second group. A horizontal bus line for a group is formed on each channel region of the first and second horizontal CCD registers so as to cross the first electrode portion and the second electrode portion, respectively. Solid-state imaging device. 2. Two horizontal bus lines for the first group and two horizontal bus lines for the second group are formed on each channel region of the first and second horizontal CCD registers, and the horizontal transfer electrodes are provided on each channel. The solid-state image pickup device according to claim 1, wherein the solid-state image pickup devices are alternately connected to each other. 3. A bus line for supplying a pulse to the transfer electrodes between horizontal registers is formed in parallel with an upper region of the transfer electrodes between horizontal registers and connected to the bus line. The solid-state imaging device according to. 4. A bus line for supplying a pulse to the vertical / horizontal register transfer electrode is formed in parallel with an upper region of the vertical / horizontal register transfer electrode and connected to the bus line. The solid-state imaging device according to claim 3.