JP3477727B2 - Solid-state imaging device - Google Patents

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 sensor, and more particularly to a solid-state image sensor suitable for use in an interline transfer type CCD image sensor and a frame / interline transfer type CCD image sensor.

[0002]

2. Description of the Related Art A transfer electrode in a vertical register of a conventional CCD solid-state image pickup device, for example, has a conductive wire portion extending in the horizontal direction and an electrode portion protruding along the vertical register integrally formed of, for example, a polycrystalline silicon layer. Wiring is done.

A CCD solid-state image pickup device of the all-pixel readout system which has three layers of transfer electrodes and is supplied with drive pulses of three phases having different phases, is shown in FIG. 19 and FIG. As shown in FIG. 20, the transfer electrode 21 formed of the first-layer polycrystalline silicon layer has a first conducting wire 21a extending horizontally between the light receiving portions 26 in the vertical direction (regions indicated by width Ws in FIG. 20). And the vertical register 2
7 (region indicated by width Wr in FIG. 20) and a first electrode portion 21b projecting downward in the drawing (see solid line), and a transfer electrode formed of a second polycrystalline silicon layer. 22 is composed of a second conductive wire 22a extending in the horizontal direction on the first conductive wire 21a, and a second electrode portion 22b protruding upward in the drawing along the vertical register 27 (see a broken line), The transfer electrode 23 formed of the third-layer polycrystalline silicon layer has a third conductive wire 23a extending in the horizontal direction on the second conductive wire 22a and a vertical register 27 along the vertical register 27. It is composed of a third electrode portion 23b protruding further downward than the end portion of the portion 22b (see the alternate long and short dash line). In FIG. 20, the region indicated by the width Wc is the channel stopper region 28.

However, in the above-mentioned conventional CCD solid-state image pickup device, the first and the first transfer electrodes 21, 22 and 23 in the space between the light receiving portions 26 in the vertical direction.
The second and third conducting wire portions 21a, 22a and 23a are wired, and the transfer electrodes 21, 22 and 23 are also arranged.
Since the misalignment must be taken into consideration when forming by patterning, the conductive wire portions 21a, 22
It is necessary to reduce the wiring width of a and 23a toward the upper layer. That is, the first, second and third conductor portions 21
If the wiring widths of a, 22a, and 23a are W ₁ , W _2, and W ₃ , then it is necessary to satisfy the relationship of W ₁ > W ₂ > W ₃ .

As described above, since the wiring width W ₃ in the third conductor portion 23a is the narrowest, the third conductor portion 2
The wiring resistance in 3a becomes high, which causes a drive pulse propagation delay. This propagation delay of the drive pulse causes a handling charge failure, a charge transfer failure, etc. of the vertical register 27, which causes a problem that the image quality is significantly deteriorated. In particular, when driving pulses are supplied from the left and right ends of each transfer electrode 21, 22, 23, propagation delay of the driving pulse occurs in the central portion of the image area, and handling defects or charge transfer defects in the central portion occur. There was the inconvenience of inviting such things.

[0006] Therefore, the third conductor portion 23a may be formed by widely the wiring width W _3, but in this case, the wiring width W ₁ of the first conductor portion 21a is wider,
The opening width of the light receiving portion 26 becomes narrower by that amount, which causes a problem that sensitivity is deteriorated. The second and third conductors portions 22a and 23a but the method is also conceivable to form in the same respective line widths W ₂ and W _3, the form of misalignment or the like during the patterning is extremely difficult.

As another method, each transfer electrode 2
It is conceivable that 1, 22, 23 are composed of a polycrystalline silicon layer and, for example, a tungsten silicide layer, that is, have a polycide structure. In this case, there is an advantage that the wiring resistance can be significantly reduced as compared with the case where the transfer electrode is formed only by the polycrystalline silicon layer.

However, when the CCD solid-state image pickup device is applied to, for example, a frame / interline transfer type image sensor, the charge transfer speed is required to be 40 to 100 times as high as that of the interline transfer type image sensor. Therefore, there is a problem that it cannot be dealt with by simply lowering the resistance of the transfer electrode. Moreover, in the case of the above-mentioned method, there is a process problem that new process development is necessary because it is not completed to the level where the current characteristics are deteriorated at this stage.

Under these circumstances, conventionally, a technique has been proposed in which three layers of transfer electrodes are shunted with a metal film such as Al. That is, in the transfer electrode pattern of FIG. 20 described above, the first electrode portion 21b in the transfer electrode 21 of the first layer is
Is the third electrode portion 23b of the transfer electrode 23 of the third layer.
Therefore, the shunt structure in which the metal film is electrically connected to the transfer electrodes 21, 22, and 23 of each layer cannot be taken.

Therefore, as shown in FIG. 21, the transfer electrode 23 of the third layer is formed in the horizontal direction across the light receiving portion 26,
The electrode portions 21b, 22b of the transfer electrodes 21, 22, 23,
It is considered to expose 23b. in this case,
The metal film 31 formed along the vertical register on each transfer electrode 21, 22, 23 and each transfer electrode 21, 22, 22.
The electrical connection with 23 becomes easy, and the shunt structure can be easily obtained. In the illustrated example, for the 3n + 1th column (n = 0, 1, 2, ...) For example, the transfer electrode (third electrode portion 23b) of the third layer is connected to the metal film 31,
For the 3n + 2th column, the first-layer transfer electrode (first electrode portion 21b) is connected to the metal film 31, and for the 3n + 3th column, the second-layer transfer electrode (second electrode portion 22b) is connected. An example in which the metal film 31 is connected is shown.

[0011]

However, in the CCD solid-state image pickup device shown in FIG. 21, the transfer electrode 23 of the third layer, particularly the third conductive wire portion 23a, crosses the light receiving portion 26. The effective aperture ratio of the light receiving unit 26 decreases, the influence of noise (shot noise) of the signal charge at low illuminance increases, and the surface of the light receiving unit 26 becomes depleted due to the voltage condition of the drive pulse supplied. However, there is a disadvantage that the dark current increases.

On the other hand, in another proposed example, as shown in FIGS. 22 to 25, the first transfer electrode 21 of the first layer is used.
The electrode portion 21b of the second electrode portion 22b of the second transfer electrode 22 is formed along the vertical register in the drawing so as to project downward in the drawing (see FIG. 23). It is formed so as to project upward (see FIG. 24). Then, as shown in FIG. 25, the transfer electrodes 23 of the third layer are projected downward in the drawing along short-circuit electrode portions 23S extending in the vertical transfer direction in a certain column and along the vertical registers in the other columns. The first electrode portion 2 formed so that
3b ₁ and the second electrode portion 23b formed so as to project upward in the drawing along the vertical register in another column.
_{Consists of 2} and.

Then, as shown in FIG. 22, the transfer electrodes 21, 22, and 23 are sequentially stacked to form the light receiving portion 2.
The transfer electrodes 23 of the third layer are not crossed over the transfer electrode 21, and the electrode portions 21b, 22b, 23b of the transfer electrodes 21, 22, 23 are provided.
₁ , 23b ₂ can be exposed, and an all-pixel readout CCD image sensor of the frame / interline transfer system can be realized without causing deterioration of characteristics.

In the CCD solid-state image pickup device shown in FIG. 22, all pixels are generally read out, which is advantageous in non-interlaced image processing, for example, in terms of simplification of a signal processing circuit in the subsequent stage.

However, the three-layer transfer electrodes 21, 22, 2
When the CCD solid-state image pickup device having 3 is applied to image processing of an interlace system such as the NTSC system,
A field reading method and a frame reading method are required for the signal charge reading method. In the CCD solid-state image pickup device, when the signal charges of the light receiving section 26 are read out below the transfer electrode 21 of the first layer or below the transfer electrode 22 of the second layer, it is not possible to correspond to the field reading method or the frame reading method. However, the light receiving part 2 is formed under the transfer electrode 23 of the third layer.
When the signal charges from 6 are read, the field reading method and the frame reading method cannot be performed.

As a practical matter, it is desirable to read at the third layer of electrodes. This is because the electrode of the third layer faces the center of the light receiving part, and it is easy to apply an electric field for reading to the entire light receiving part, and when reading with this electrode, the frontage from the light receiving part to the channel is the widest. Is. Hereinafter, it is assumed that the reading is performed by the third layer electrode. Further, when reading is performed, the reading potential is applied to the reading electrodes all at once, but at this time, the following problems occur.
That is, the substrate potential is affected by the potential applied to the electrodes, which makes it difficult to read, or requires a higher potential for reading. Therefore, it is better to shift the timing of reading for each row, for example. Also, the electrode area should be as small as possible. This is to reduce the influence on the substrate potential.

However, in the CCD solid state image pickup device shown in FIG. 22, the transfer electrodes of the third layer are as shown in FIG.
Since only the same drive pulse is supplied to the short circuit electrode portion 23S, it is impossible to realize the above drive.

The present invention has been made in view of the above problems. An object of the present invention is to read the signal charge from the light receiving portion under the transfer charge of the third layer, and to use the non-interlaced system. Another object of the present invention is to provide a solid-state image sensor capable of easily performing field reading and frame reading corresponding to an interlace system, in addition to corresponding reading of all pixels.

[0019]

According to the present invention, a large number of rows of charge transfer regions for vertically transferring the signal charges from the light receiving portion 4 are formed, and first and second charge transfer regions are formed on each charge transfer region in the transfer direction.
A plurality of transfer electrodes 1, 2 and 3 composed of second and third layers are formed, and the transfer electrode 1 of the first layer has a first conducting wire portion 1a extending horizontally between the light receiving portions 4 and each row. A second conductive wire portion 2a, which is formed of a first electrode portion 1b protruding in the transfer direction side on the charge transfer region of the second transfer electrode 2 and extends in the horizontal direction between the light receiving portions 4; A third conductive wire portion formed of a second electrode portion 2b protruding in the opposite direction to the transfer direction on the charge transfer region of the column, and the transfer electrode 3 of the third layer extending horizontally between the light receiving portions 4 3a and the adjacent row of charge transfer regions
Or projecting direction is reversed, or is formed from the third electrode portion 3b _1, 3b ₂ Metropolitan the projecting direction is reversed in a column of each pair between every third row and said every third column, The metal film 8 is arranged along the charge transfer region of each column, and the metal film 8 of each column is connected to the metal film 8 of the same column so as to be connected to the electrode portion of the same layer.
Are arranged in the order of arrangement of the metal films 8 in order of the first, second and third.
Connected to the electrode parts 1b, 2b, 3b 1, 3b2 of
It

Further, according to the present invention, a large number of columns of charge transfer regions for vertically transferring the signal charges from the light receiving section 4 are formed, and the first, second and third charge transfer regions are formed on the respective charge transfer regions in the transfer direction. A plurality of transfer electrodes 1, 2 and 3 are formed, and the transfer electrode 1 of the first layer has a first conductive wire portion 1a extending horizontally between the light receiving portions 4 and the charge transfer regions of each column. A second conductive wire portion 2a which is formed of a first electrode portion 1b projecting toward the transfer direction side and which extends in the horizontal direction between the light receiving portions 4 and a charge transfer region of each column. A third conductive wire portion 3a, which is formed of a second electrode portion 2b projecting to the opposite side to the transfer direction above, extends in the horizontal direction between the light receiving portions 4 and a transfer electrode 3 of the third layer, and charge transfer. The protruding directions are opposite in adjacent rows of regions, or every other row and every pair of rows between every other row. The third electrode portions 3b ₁ and 3b ₂ having opposite projecting directions are formed on the charge transfer regions of each column.
Metal film 8 are arranged along the, in the same column of the metal film 8 same
In order to connect the electrode portions of the layers , the metal films 8 in each column are arranged in order in the arrangement direction of the metal films 8 and one light receiving unit is arranged in the column of the light receiving units 4 corresponding to the vertical charge transfer region. At positions corresponding to the first, second and third electrode portions 1b, 2b, 3
It is connected to b 1 and 3 b 2 .

Further, according to the present invention, a large number of columns of charge transfer regions for transferring the signal charges from the light receiving section 4 in the vertical direction are formed,
A plurality of transfer electrodes 1, 2, 3 composed of first, second and third layers are formed on each charge transfer region in the transfer direction,
The transfer electrode 1 of the first layer is formed of a first conductive wire portion 1a extending horizontally between the light receiving portions 4 and a first electrode portion 1b protruding in the transfer direction side on the charge transfer region of each column. , A second conductive wire portion 2a in which the transfer electrode 2 of the second layer extends horizontally between the light receiving portions 4, and a second electrode portion 2b protruding in the opposite side to the transfer direction on the charge transfer region of each column. And a third conductive wire portion 3a formed by a transfer electrode 3 of the third layer and extending horizontally between the light receiving portions 4 and the protruding direction in the adjacent row of the charge transfer region is opposite or two. Third electrode portion 3b in which the protruding direction is opposite between the alternate row and each pair of rows between the alternate rows.
₁ and 3b ₂ and each of the light receiving parts 4 has a first and second
And the third three electrode portions 1b, 2b, 3b1, 3b2 correspond to each other , and the third electrode portions 1b, 2b, 3b1, 3b2 are arranged on the charge transfer region in the transfer direction.
Electrode portion 3b1,3b2 is disposed between the first electrodes portion 1b and the second electrode portion 2b, the metal film 8 are arranged along the charge transfer region of each column, on the same level of the metal film 8 Are connected to the metal films 8 in each column so that the electrode parts of the same layer are connected.
The first, second, and third electrode portions 1 in order in the arrangement direction of
b, 2b, 3b 1 , 3b 2 are connected .

The metal film 8 connected to the electrode portions 3b ₁ and 3b ₂ of the third layer is provided with a means for giving a read potential for reading out the charges of the light receiving portion 4.

[0023]

According to the first configuration of the present invention described above, the first and the second
The transfer electrodes 1, 2 and 3 of the second and third layers are formed in the above pattern, and the metal film 8 is formed along the charge transfer region of each column.
Are arranged, and the metal films 8 in each row are arranged in order in the arrangement direction of the metal films 8 so that the electrode portions in the same layer are connected to the metal films 8 in the same row. Parts 1b, 2b, 3b 1,
By connecting to 3b2, it becomes possible to supply drive pulses having different phases to the transfer electrodes 1, 2 and 3 of the adjacent rows. As a result, pseudo four-phase driving can be performed, and field reading and frame reading can be performed when the signal charge from the light receiving section 4 is read under the transfer electrode 3 of the third layer.

Further, according to the second aspect of the present invention, the
The transfer electrodes 1, 2, and 3 of the first, second, and third layers are formed in the above pattern, and gold is formed along the charge transfer region of each column.
The Shokumaku 8 placed, as is on the same level of the metal film 8 is connected to the electrode portions of the same layer, and the vertical charge transfer sequentially a metal film 8 of each column in the array direction of the metal film 8 By connecting the first, second, and third electrode portions 1b, 2b, 3b1 , 3b2 at positions corresponding to every other light receiving portion in the row of the light receiving portions 4 corresponding to the region, , The first, second, and third transfer electrodes 1,
It is possible to supply different drive pulses to 2 and 3, respectively. That is, drive pulses having different phases can be supplied to the same transfer electrode, and field reading and frame reading can be performed.

Furthermore, according to the third configuration of the invention described above, first, second及 beauty third three electrode portions 1b, 2b, made to correspond to 3b 1,3B2 to the light receiving portions 4, and Transfer direction
The in the electrostatic charge transferring region 3 of the electrode portion 3b 1,3B2
Is arranged between the first electrode portion 1b and the second electrode portion 2b, an electric field for reading can be easily applied to the entire light receiving portion 4, and the reading of charges can be made satisfactory. Further, the transfer electrodes 1, 2 and 3 of the first, second and third layers are formed in the above pattern, and gold is formed along the charge transfer region of each column.
A metal film is arranged, and the metal films 8 in each row are sequentially arranged in the arrangement direction of the metal films 8 so that the electrode portions in the same layer are connected to the metal films 8 in the same row. Electrode parts 1b, 2b, 3b
By connecting to the transfer electrodes 3 and 3b2, it is possible to uniformly perform shunting by the metal wiring to the transfer electrodes 3 of the third layer to which different drive pulses are supplied.

[0026]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a plan view showing a wiring form of transfer electrodes in an image region formed by arranging essential parts of a CCD solid-state image sensor according to the first embodiment, particularly light receiving parts (pixels) in a matrix, 2 to 5 are plan views showing formation patterns of the transfer electrodes of the first to third layers, respectively. 6A and 6B are cross-sectional views taken along the line AA and BB in FIG. 1, and FIGS. 7A and 7B are cross-sectional views taken along the line CC and DD in FIG.

As shown in FIG. 1, this CCD solid-state image pickup device has three layers of transfer electrodes 1, 2 and 3, and normally, each transfer electrode 1, 2 and 3 has three different phases. The drive pulse is supplied to function as a CCD image sensor of the all-pixel readout system. In the figure, each transfer electrode 1,
2 and 3 are indicated by a one-dot chain line, a two-dot chain line and a solid line, respectively.

Looking at the sectional structure, as shown in FIG. 5, for example, on the P-type well region (not shown) on the N-type silicon substrate, for example, the light receiving portion 4 formed of a photodiode corresponding to the pixel. (Not shown in FIG. 5, see FIG. 1)
Are arranged in a matrix, and vertical registers 5 extending in the vertical direction, for example, N-type impurity diffusion regions are arranged between the light receiving portions 4 in the horizontal direction, and three vertical polycrystalline silicon layers are formed on each vertical register 5. Transfer electrodes 1, 2 and 3 are formed.

In FIG. 1, the channel stopper region and the vertical register are omitted. Further, in FIGS. 5 and 6, 6 is a gate insulating film (in this example, SiO 2,
Reference numeral 7 denotes an interlayer insulating film.

Next, the formation pattern of each transfer electrode 1, 2 and 3 will be described with reference to FIGS. In these figures, the area indicated by the alternate long and short dash line is the light receiving portion 4.

First, as shown in FIG. 2, the transfer electrode 1 of the first layer has a first conductive wire portion 1a extending in the horizontal direction between the light receiving portions 4 in the vertical direction and a vertical register in the drawing. It is composed of a first electrode portion 1b protruding downward.

As shown in FIG. 3, the transfer electrode 2 of the second layer has a second conductor portion 2a extending in the horizontal direction between the light receiving portions 4 in the vertical direction and an upward direction in the drawing along the vertical register. It is composed of a protruding second electrode portion 2b.

As shown in FIG. 4, the transfer electrodes 3 of the third layer are arranged along the vertical conductors in the third conducting wire portions 3a extending in the horizontal direction between the light receiving portions in the vertical direction and in the odd-numbered columns, for example. Third first electrode portion 3 extending downward in the drawing
b ₁ and the third second electrode portion 3b ₂ extending upward in the drawing along the vertical register in the even-numbered column. Conductor portions 1a, 2a of each transfer electrode 1, 2 and 3
In 3 and 3a, the width of each conductor portion is set to W ₁ > W ₂ > W ₃ in consideration of misalignment of patterning.

Then, the transfer electrodes 1, 2 and 3 are laminated via the interlayer insulating film 7, respectively, and further, the electrode portions 1b, 2b, 3b ₁ and 3b ₂ of the transfer electrodes 1, 2 and 3 are covered. By forming an Al pattern 8 for shunt (shown by a broken line in FIG. 1) in the vertical direction along the vertical register, the pattern shown in FIG. 1 is completed.

Therefore, in this example, the electrical connection between the transfer electrodes 1, 2 and 3 and the Al pattern 8 is made as follows. That is, for example, 6n + 1 columns and 6n + 5
As for the column (n = 0, 1, 2, ...) As shown in the cross-sectional view of FIG. 5A, all the second electrode portions 2b in the transfer electrode 2 of the second layer and the Al pattern 8 are inter-layered. Connection is made through an opening 11 provided in the insulating film 7. Regarding the 6n + 2 row and the 6n + 4 row, as shown in the cross-sectional view of FIG. 5B, all the first electrode portions 1 in the transfer electrode 1 of the first layer
b and the Al pattern 8 are connected through the opening 12 provided in the interlayer insulating film 7.

Then, regarding the 6n + 3 column and the 6n + 6 column, the third electrode portions 3b ₁ and 3b _{2 of} every third row in the transfer electrode 3 of the third layer are connected to the Al pattern 8. That is, for the 6n + 3 column, as shown in the sectional view of FIG. 6A, the third electrode portion (third first electrode portion 3b ₁ ) and the Al pattern 8 for the 2m + 1 row are provided in the interlayer insulating film 7. And the third first electrode portion 3b ₁ related to 2m + 2 rows is not connected.

As for the 6n + 6 column, as shown in the sectional view of FIG. 6B, the third electrode portion (third second electrode portion 3b ₂ ) and the Al pattern 8 related to the 2m + 2th row are provided with the interlayer insulating film 7. Connected through the opening 14 provided in the
It is not connected to the third second electrode portion 3b ₂ related to one row.
That is, 3 on the vertical register arranged every two
The electrical connection between the transfer electrode 3 of the layer and the Al pattern 8 is 1
Every other and every other column is staggered (ie staggered with respect to rows).

Next, a modified example of the first embodiment will be described with reference to FIGS. 7 and 8. FIG. 7 is a plan view showing the wiring form of the transfer electrodes in the image area according to the modification.
[FIG. 8] is a plan view showing a formation pattern of a third-layer transfer electrode 3.

The CCD solid-state image sensor according to this modification is
The structure is almost the same as that of the first embodiment, but the formation pattern of the transfer electrode 3 of the third layer is partially different. That is, as shown in FIG. 8, the transfer electrode 3 of the third layer is provided in
Between the third conductor portion 3a extending in the horizontal direction and the third first electrode portion 3b ₁ extending downward in the drawing along the vertical register in the 3n + 1th column, for example, in the 3n + 1th column.
The third row and the third row 3n + 3th row are composed of a third second electrode portion 3b ₂ extending upward in the drawing along the vertical register.

Then, the transfer electrodes 1, 2 and 3 are laminated with the interlayer insulating film 7 interposed therebetween, and further, the electrode portions 1b, 2b, 3b ₁ and 3b ₂ of the transfer electrodes 1, 2 and 3 are covered. By forming the shunt Al pattern 8 in the vertical direction along the vertical register, the pattern shown in FIG. 7 is completed.

Also in this modification, the electrical connection between the Al pattern 8 and each transfer electrode 1, 2 and 3 is almost the same as that of the first embodiment shown in FIG. The difference is that the formation pattern of the transfer electrode 3 of the third layer is as shown in FIG. 8. Therefore, regarding 6n + 3 columns, the transfer electrode of the third layer (second electrode portion 3b ₂ ) And the Al pattern 8 are not connected, but the transfer electrode (second electrode portion) of the third layer for 2m + 2 rows is connected to the Al pattern 8. In terms respect 6n + 6 rows, 2m + 1 line relates connected third layer transfer electrode (second electrode portion 3b ₂₎ and the Al pattern 8, 2m + 2 3-layer transfer electrodes about the line (second electrode portion 3b ₂ ) And the Al pattern 8 are not connected. Further, the transfer electrodes 2 of the second layer for the 6n + 1 column and the 6n + 4 column are connected to the Al pattern 8, and 6n +
Transfer electrodes 1 and Al of the first layer for the 2nd row and the 6n + 5th row
The pattern 8 is connected.

As described above, according to the first embodiment and the modification, it is possible to supply drive pulses having different phases to the transfer electrodes 3 of the third layer in the adjacent row. As a result, pseudo four-phase driving can be performed, and field reading and frame reading can be performed when the signal charge from the light receiving section 4 is read under the transfer electrode 3 of the third layer.

An example in which signal charges are transferred by, for example, field reading by pseudo four-phase driving will be described with reference to FIGS. 9 to 12. In these figures, Vφ1 and Vφ2 represent drive pulses supplied to the transfer electrodes 1 and 2 of the first and second layers, respectively, regardless of the row, and Vφ3A and Vφ3B are 3 related to 2m + 1 row and 2m + 2 row, respectively. The drive pulse supplied to the transfer electrode 3 of the layer is shown.

Further, in the first embodiment and its modification, the formation patterns of the third transfer electrodes 3 for the 6n + 1 column and the 6n + 2 column are different, but the signal charge transfer state in each column is the same. 10 and 12 representatively show the transfer state of the signal charges for the 6n + 1 column of the first embodiment.

First, the first field will be described with reference to FIGS. 9 and 10. First, at t1, Vφ
Since 1, Vφ2, Vφ3A, and Vφ3B are high level, low level, high level, and high level, respectively, potential wells are continuously formed under the transfer electrodes 1 and 3 of the first and third layers.

Next, at time t2, Vφ3B becomes the read level (higher than the above high level), and the signal charge e ₂ from the light receiving section 4, particularly the light receiving section 4 for the 2m + 2 row, is in the third layer for the 2m + 2 row. Transferred and stored under the transfer electrode 3.

Next, at time t3, since Vφ3B changes to a normal high level, the signal charge e ₂ is generated in the potential wells continuously formed under the transfer electrodes 1 and 3 of the first and third layers. Transferred / stored.

Next, in a section T, three-phase drive pulses Vφ1 to Vφ3 (Vφ3A, Vφ3) having mutually different phases.
B) is supplied to the transfer electrodes 1 to 3 of the first to third layers, respectively, so that at the next time t4, the signal charge e ₂ is 1 in the next row, as indicated by the arrow in the figure. Layers and 3
It is transferred and accumulated in the potential well formed continuously under the transfer electrodes 1 and 3 of the layer.

Next, at time t5, this time Vφ3A
Becomes the read level, and the signal charge e ₁ from the light receiving portion 4, particularly the light receiving portion 4 regarding the 2m + 1 row is transferred and accumulated under the transfer electrode 3 of the third layer regarding the 2m + 1 row and mixed with the signal charge e ₂ regarding the 2m + 2 row. It To be precise, 3m + 2
The signal charges for the rows and the signal charges for the 3m + 3 rows are mixed.

Next, at time t6, since Vφ3A changes to the normal high level, the mixed signal charge (e
₁ + e ₂ ) is transferred and accumulated in potential wells formed continuously under the transfer electrodes 1 and 3 of the first and third layers.

After that, three-phase drive pulses Vφ1 to Vφ3 (Vφ) having different phases are applied to the transfer electrodes 1, 2 and 3, respectively.
3A, Vφ3B) to supply the signal charge (e ₁ +
e ₂ ) are sequentially transferred to the horizontal register side.

Next, the second field will be described with reference to FIGS. 11 and 12. First, at t1, Vφ
Since 1, Vφ2, Vφ3A, and Vφ3B are high level, low level, high level, and high level, respectively, potential wells are continuously formed under the transfer electrodes 1 and 3 of the first and third layers.

Next, at time t2, Vφ3A becomes the reading level, and the signal charge e ₁ from the light receiving portion 4, particularly the light receiving portion 4 for the 2m + 1 row is transferred / stored under the third transfer electrode 3 for the 2m + 1 row. It

Next, at time t3, since Vφ3A changes to a normal high level, the signal charge e ₁ is generated in the potential wells continuously formed under the transfer electrodes 1 and 3 of the first and third layers. Transferred / stored.

Next, in section T, three-phase drive pulses Vφ1 to Vφ3 (Vφ3A, Vφ3) having mutually different phases.
B) is supplied to the transfer electrodes 1 to 3 of the first to third layers, respectively, so that at the next time t4, the signal charge e ₁ is ₁ in the next row, as indicated by the arrow in the figure. Layers and 3
It is transferred and accumulated in the potential well formed continuously under the transfer electrodes 1 and 3 of the layer.

Next, at time t5, this time Vφ3B
Becomes the read level, and the signal charge e ₂ from the light receiving portion 4, particularly the light receiving portion 4 regarding the 2m + 2 row is transferred and accumulated under the transfer electrode 3 of the third layer regarding the 2m + 2 row and mixed with the signal charge e ₁ regarding the 2m + 1 row. It To be precise, 3m + 1
The signal charge for the row and the signal charge for the 3m + 2 row are mixed.

Next, at time t6, since Vφ3A changes to the normal high level, the mixed signal charge (e
₁ + e ₂ ) is transferred and accumulated in potential wells formed continuously under the transfer electrodes 1 and 3 of the first and third layers.

Thereafter, three-phase drive pulses Vφ1 to Vφ3 (Vφ) having different phases are applied to the transfer electrodes 1, 2 and 3, respectively.
3A, Vφ3B) to supply the signal charge (e ₁ +
e ₂ ) are sequentially transferred to the horizontal register side.

It should be noted that the frame reading is performed at t5 in each of the first and second fields shown in FIGS. 9 and 11.
At this time, Vφ3A and Vφ3B may be set to a normal high level instead of the read level.

As described above, by adopting the configuration according to the first embodiment and the modified example, that is, the electrical connection between the transfer electrode 3 of the third layer and the Al pattern 8 on the vertical registers arranged every two rows. Since only one connection is provided in the same column, not only all-pixel reading corresponding to the non-interlace method but also field reading or frame reading corresponding to the interlace method can be easily achieved.

Further, since the electrical connection between the transfer electrode 3 of the third layer and the Al pattern 8 is alternated between every two columns, the transfer electrode 3 of the third layer to which Vφ3A is supplied is supplied. And Vφ3B are supplied to the third-layer transfer electrode 3
The shunt with the Al pattern 8 can be uniformly performed.

In this example, the transfer electrode 3 of the third layer is arranged so as to face the center of the light receiving portion 4, and when the charges are read from the light receiving portion 4 to the vertical register 5, the transfer electrode 3 of the third layer is arranged.
Since the reading is performed downward, an electric field for reading is easily applied to the entire light receiving portion, and the frontage from the light receiving portion to the channel is widest, so that good charge reading can be performed.

However, the video signal read by this embodiment causes a slight shift in the horizontal direction due to the fact that the transfer electrodes of the third layer which are the read electrodes are staggered. The second embodiment which solves this problem will be described below.
This will be shown as an example.

A CCD solid-state image pickup device according to the second embodiment will be described with reference to FIGS. The same reference numerals are given to those corresponding to the first embodiment.

The CCD solid-state image pickup device according to the second embodiment has substantially the same structure as that of the first embodiment, but there is a difference in the connection state between the transfer electrodes 1, 2 and 3 and the Al pattern 8.

That is, as shown in FIG. 13, for example, 6n +
Regarding the 1st column and the 6n + 5th column, the second electrode portion 2b and the Al pattern 8 in every other row in the transfer electrode 2 of the second layer are separated.
And are connected through an opening provided in the interlayer insulating film. That is, regarding the 6n + 1 column, the second electrode portion 2b for the 2m + 1 row is not connected to the Al pattern 8, but is connected to the second electrode portion 2b for the 2m + 2 row.

Further, regarding the 6n + 5th column, the second electrode portion 2b for the 2m + 1th row is connected to the Al pattern 8 and is not connected to the second electrode portion 2b for the 2m + 2th row. That is, every other electrical connection between the transfer electrodes 2b of the second layer and the Al pattern 8 on the vertical register arranged every three rows is alternated, and every three columns are alternated (that is, alternated with respect to rows). ).

Next, regarding the 6n + 2 column and the 6n + 4 column, the first electrode portion 1b and the Al pattern 9 in every other row in the transfer electrode 1 of the first layer are connected through the opening provided in the interlayer insulating film. To do. That is, for the 6n + 2 column,
First electrode portion 1b and Al pattern 8 for 2m + 1 rows
Are connected, but not to the first electrode portion 1b related to 2m + 2 rows.

Regarding the 6n + 4th column, the first electrode portion 1b for the 2m + 1th row is not connected to the Al pattern 8, but is connected to the first electrode portion 1b for the 2m + 2th row.
That is, also in this case, the electrical connection between the transfer electrodes 1 of the first layer and the Al pattern 8 on the vertical registers arranged every other row is alternated, and the electrical connection is alternated between every other columns ( That is, staggered with respect to the line).

Next, regarding the 6n + 3 column and the 6n + 6 column, the openings provided in the interlayer insulating film with the third electrode portions 3b ₁ and 3b ₂ and the Al pattern 8 in every other row in the transfer electrode 3 of the third layer. Connect through. That is, for 6n + 3 columns, the third first electrode portion 3b for 2m + 1 rows is used.
₁ and the Al pattern 8 are connected, but not connected to the third first electrode portion 3b ₁ related to 2m + 2 rows.

[0071] With respect to the 6n + 6 rows, 2m + 2 line and for the connection with the third second electrode portion 3b ₂ and the Al pattern 8, 2m + 1 and the third second the electrode portion 3b ₂ of about line not connected. That is, in this case as well, the electrical connection between the transfer electrodes 3 of the third layer and the Al pattern 8 on the vertical registers arranged every two rows is alternated, and the electrical connection is alternated between every two columns. That is, staggered with respect to the line).

Next, a modification of the second embodiment will be described with reference to FIG. The CCD solid-state image sensor according to this modification has almost the same configuration as that of the modification of the first embodiment, but there is a difference in the connection state between the transfer electrodes 1, 2 and 3 and the Al pattern 8. Since this connection state is almost the same as that of the second embodiment, detailed description thereof will be omitted. The difference is that the formation pattern of the transfer electrode 3 of the third layer is as shown in FIG. 8. Therefore, regarding 6n + 3 columns, the transfer electrode of the third layer (second electrode portion 3b ₂ ) And the Al pattern 8 are not connected to each other, and the transfer electrode (second electrode portion 3b ₂ ) of the third layer for 2m + 2 rows and Al
The pattern 8 is connected. In addition, regarding the 6n + 6 column, the transfer electrode (second electrode portion 3b ₂ ) of the third layer regarding the 2m + 2 row and the Al pattern 8 are connected to each other, and 2m + 2
A transfer electrode (second electrode portion 3b ₂ ) of the third layer related to the row and A
l pattern 8 is not connected. The transfer electrodes 2 of the second layer for the 6n + 1 column and the 6n + 4 column are connected to the Al pattern 8, and 1 for the 6n + 2 column and the 6n + 5 column.
The transfer electrode 1 of the layer and the Al pattern 8 are connected.

According to this second embodiment and its modification,
Transfer electrodes 1 to 3 on the first to third layers between adjacent rows
It is possible to supply drive pulses having different phases to each other. That is, drive pulses having different phases can be supplied to the same transfer electrode, and field reading and frame reading can be performed without reducing the amount of charges handled by the vertical register.

Here, based on FIGS. 15 to 18, the pseudo 6
An example in which signal charges are transferred by, for example, field reading by phase driving will be described. In these figures, Vφ1A,
Vφ2A and Vφ3A are, for example, 1 for 2m + 1 rows.
Drive pulses supplied to the transfer electrodes 1, 2, and 3 of the second, third, and third layers are shown as Vφ1B, Vφ2B, and Vφ.
3B shows a drive pulse supplied to the transfer electrodes 1, 2 and 3 of the first layer, the second layer and the third layer for, for example, 2m + 2 rows.

Also in this case, although the formation pattern of the third transfer electrodes 3 for the 6n + 1 column and the 6n + 2 column is different, the transfer state of the signal charges in each column is the same, and therefore, in FIGS. 16 and 18. Also, the transfer state of the signal charges for the 6n + 2 column of the second embodiment is representatively shown.

First, the first field will be described with reference to FIGS. 15 and 16. First, at time t1, V
Since only φ1A and Vφ2A are at a low level and the subsequent drive pulse is at a high level, a potential well is continuously formed from below the third transfer electrode 3 of the 2m + 1 row to below the third transfer electrode 3 of the 2m + 2 row. It

Next, at time t2, Vφ3A becomes the read level, and the signal charge e ₁ from the light receiving portion 4 is transferred and accumulated under the corresponding transfer electrode 3 of the third layer.

Next, at time t3, Vφ3B becomes the reading level, and the signal charge e ₂ from the light receiving portion 4 is transferred and accumulated under the corresponding transfer electrode 3 of the third layer.

Next, at t4, Vφ3A and Vφ
Since 3B changes to the low level, the signal charges e ₁ and e ₂ are accumulated in the potential well formed continuously below the transfer electrode 1 of the first layer and the transfer electrode 3 of the second layer for the 2m + 2 row, The signal charges e ₁ and e ₂ for the 2m + 1 and 2m + 2 rows are mixed.

After that, three-phase drive pulses (Vφ1A, Vφ2) having different phases are applied to the transfer electrodes 1, 2 and 3, respectively.
A, Vφ3A, Vφ1B, Vφ2B, Vφ3B) are supplied to sequentially transfer the signal charges (e ₁ + e ₂ ) to the horizontal register side.

Next, the second field will be described with reference to FIGS. 17 and 18. First, at t1, Vφ
Since 1B and Vφ2B are at a low level and the subsequent drive pulse is at a high level, a potential well is continuously formed from below the third transfer electrode 3 of the 2m + 1 row to below the third transfer electrode 3 of the 2m + 2 row. .

Next, at time t2, Vφ3A becomes the read level, and the signal charge e ₁ from the light receiving portion 4 is transferred / stored under the corresponding transfer electrode 3 of the third layer.

Next, at time t3, Vφ3B becomes the read level, and the signal charge e ₂ from the light receiving portion 4 is transferred and accumulated under the corresponding transfer electrode 3 of the third layer.

Next, at time t4, Vφ3A and Vφ
Since 3B changes to the low level, the signal charges e ₁ and e ₂ are accumulated in the potential well formed continuously under the transfer electrode 1 of the first layer and the transfer electrode 2 of the second layer for the 2m + 1th row, The signal charges e ₁ and e ₂ for the 2m + 1 and 2m + 2 rows are mixed.

After that, three-phase drive pulses (Vφ1A, Vφ2) having different phases are applied to the transfer electrodes 1, 2 and 3, respectively.
A, Vφ3A, Vφ1B, Vφ2B, Vφ3B) are supplied to sequentially transfer the signal charges (e ₁ + e ₂ ) to the horizontal register side.

As described above, by adopting the configurations according to the second embodiment and the modified example, that is, the transfer electrodes 1, 2 and 3 which are different from each other in each adjacent column are arranged in each column. Since it is electrically connected to the Al pattern 8 in the above, it is possible to supply drive pulses having different phases to the same transfer electrode between adjacent rows, and to realize the pseudo 6-phase drive as described above. While you can
It is possible to easily achieve all-pixel reading compatible with the non-interlaced method and field reading or frame reading compatible with the interlaced method.

Further, the electrical connection between the transfer electrodes 1, 2 and 3 and the Al pattern 8 is alternated between one row and a predetermined number of rows with respect to the row. The shunt by the Al pattern 8 for 1, 2 and 3 can be performed uniformly.

It should be noted that the frame reading is performed by the first frame shown in FIG.
At time t2 in the field, Vφ3A is not set to the read level, and is set to the normal high level.
At time t3 in the second field shown by 7, Vφ
It can be realized by setting 3B to a normal high level instead of the read level.

[0089]

According to the solid-state image pickup device of the present invention, the signal charge from the light receiving portion can be read out under the transfer electrode of the third layer , and in addition to the non-interlaced type all pixel read-out, the interlaced read-out can be performed. It is possible to easily perform field reading and frame reading corresponding to the method.

[Brief description of drawings]

FIG. 1 is a main part of a CCD solid-state imaging device according to a first embodiment,
In particular, a plan view showing the wiring form of the transfer electrodes in an image region configured by arranging light receiving portions (pixels) in a matrix.

FIG. 2 is a plan view showing a formation pattern of a first-layer transfer electrode according to the first embodiment.

FIG. 3 is a plan view showing a formation pattern of a second-layer transfer electrode according to the first embodiment.

FIG. 4 is a plan view showing a formation pattern of a third-layer transfer electrode according to the first embodiment.

5A is a cross-sectional view taken along the line AA in FIG. B
Is a cross-sectional view taken along the line BB in FIG. 1.

6A is a cross-sectional view taken along the line CC of FIG. B
[FIG. 2] is a sectional view taken along the line D-D in FIG. 1.

FIG. 7 is a plan view showing a wiring form of transfer electrodes according to a modification of the first embodiment.

FIG. 8 is a plan view showing a formation pattern of a third-layer transfer electrode according to a modification of the first embodiment.

FIG. 9 is a time chart showing the output timing of the drive pulse in the first field in the first embodiment.

FIG. 10 is an operation conceptual diagram showing a charge transfer state in the first field in the first embodiment.

FIG. 11 is a time chart showing the output timing of the drive pulse in the second field in the first embodiment.

FIG. 12 is an operation conceptual diagram showing a charge transfer state in the second field in the first embodiment.

FIG. 13 is a plan view showing a wiring form of transfer electrodes according to the second embodiment.

FIG. 14 is a plan view showing a wiring form of transfer electrodes according to a modification of the second embodiment.

FIG. 15 is a time chart showing the output timing of the drive pulse in the first field in the second embodiment.

FIG. 16 is an operation conceptual diagram showing a charge transfer state in the first field in the second embodiment.

FIG. 17 is a time chart showing the output timing of drive pulses in the second field in the second embodiment.

FIG. 18 is an operation conceptual diagram showing a charge transfer state in the second field in the second embodiment.

FIG. 19 is an enlarged perspective view showing a wiring form of transfer electrodes according to a conventional example.

FIG. 20 is a plan view showing a wiring form of transfer electrodes according to a conventional example.

FIG. 21 is a plan view showing a wiring form of transfer electrodes according to a proposed example.

FIG. 22 is a plan view showing a wiring form of transfer electrodes according to another proposed example.

FIG. 23 is a plan view showing a formation pattern of a first-layer transfer electrode according to another proposed example.

FIG. 24 is a plan view showing a formation pattern of a second-layer transfer electrode according to another proposed example.

FIG. 25 is a plan view showing a formation pattern of a third-layer transfer electrode according to another proposed example.

[Explanation of symbols]

1 1st layer transfer electrode 1a 1st conductor part 1b 1st electrode part 2 2nd layer transfer electrode 2a 2nd conductor part 2b 2nd electrode part 3 3rd layer transfer electrode 3a 3rd conductor wire Part 3b ₁ third first electrode part 3b ₂ third second electrode part 4 light receiving part 5 vertical register 6 gate insulating film 7 interlayer insulating film 8 Al pattern

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-20866 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 27/148 H04N 5/335

Claims (4)

(57) [Claims] 1. A plurality of rows of charge transfer regions for vertically transferring signal charges from a light receiving portion are formed, and a plurality of charge transfer regions each including a first layer, a second layer, and a third layer are formed on the respective charge transfer regions in the transfer direction. Transfer electrodes of the first layer are formed, and the transfer electrodes of the first layer extend in the horizontal direction between the light receiving portions and the first conductive wire portions that protrude toward the transfer direction side on the charge transfer regions of each column. A transfer electrode of a second layer, which is formed of an electrode portion, and a second conductive wire portion that extends between the light receiving portions in the horizontal direction and the charge transfer region of each column, protrudes in the opposite direction to the transfer direction. The transfer electrode of the third layer, which is formed of the second electrode portion, has the third conductive wire portion extending horizontally between the light receiving portions and the projecting direction of the adjacent column of the charge transfer region opposite to each other. Or a third electrode in which the protruding direction is opposite between every other row and each pair of rows between the two rows. And a metal film is arranged along the charge transfer region of each column, and the electrode parts of the same layer are connected to the metal film of the same column,
The solid-state imaging device, wherein the metal film of each column is sequentially connected to the first, second, and third electrode portions in the arrangement direction of the metal film . 2. A plurality of charge transfer regions for vertically transferring a signal charge from a light receiving portion are formed in a plurality of columns, and a plurality of charge transfer regions formed on the respective charge transfer regions are formed of first, second and third layers in the transfer direction. Transfer electrodes of the first layer are formed, and the transfer electrodes of the first layer extend in the horizontal direction between the light receiving portions and the first conductive wire portions that protrude toward the transfer direction side on the charge transfer regions of each column. A transfer electrode of a second layer, which is formed of an electrode portion, and a second conductive wire portion that extends between the light receiving portions in the horizontal direction and the charge transfer region of each column, protrudes in the opposite direction to the transfer direction. The transfer electrode of the third layer, which is formed of the second electrode portion, has the third conductive wire portion extending horizontally between the light receiving portions and the projecting direction of the adjacent column of the charge transfer region opposite to each other. Or a third electrode in which the protruding direction is opposite between every other row and each pair of rows between the two rows. And a metal film is arranged along the charge transfer region of each column, and the electrode parts of the same layer are connected to the metal film of the same column,
The first and second metal films are arranged at the positions corresponding to every other light receiving unit in the column of the light receiving units corresponding to the charge transfer regions in the vertical direction in which the metal films of each column are arranged in order. , Third
A solid-state image pickup device characterized by being connected to the electrode part of. 3. A plurality of charge transfer regions for vertically transferring signal charges from a light receiving portion are formed in a column, and a plurality of charge transfer regions formed on the respective charge transfer regions are formed of first, second and third layers in the transfer direction. Transfer electrodes of the first layer are formed, and the first transfer electrode of the first layer protrudes toward the transfer direction side on the charge transfer region of each column and the first conductive wire part that extends horizontally between the light receiving parts. The transfer electrode of the second layer, the transfer electrode of the second layer extending in the horizontal direction between the light receiving parts and the charge transfer region of each column on the opposite side to the transfer direction. A transfer electrode of the third layer, which is formed of a protruding second electrode portion, and a third conductive wire portion that extends horizontally between the light receiving portions, and a protruding direction in a column adjacent to the charge transfer region. Reversed, or with every other row and each pair of rows between every other row, protruding directions reversed. 3rd
And each of the light receiving portions includes the first, second, and third electrodes.
Parts correspond, and are disposed between the third electrode portion in the charge transfer region and have contact to the transfer direction and the first electrode portion and the second electrode portion, a charge transfer of each column A metal film is arranged along the area, and the electrode parts of the same layer are connected to the metal films in the same row.
The solid-state imaging device, wherein the metal film of each column is connected to the first, second, and third electrode portions in order in the arrangement direction of the metal film . 4. The solid-state imaging device according to claim 3, further comprising means for applying a read potential for reading out charges of the light receiving section to the metal film connected to the third electrode section.