JPS6125391A - Color solid-state image pickup device - Google Patents

Abstract

PURPOSE:To obtain an excellent reproduction picture high in color repeatability by forming a light-shielding film on a surface protection film of a lower electrode, and reflecting unnecessary incident light beams to prevent a color mixing phenomenon. CONSTITUTION:Light-shielding films 11 made of Al are formed on a surface protection film 9 in positions of lower electrodes 4, 4..., and for instance, Al vapor deposition and etching processing are executed so that the films 11 of the same width as those of the electrodes 4 can extend just above the electrodes 4, 4.... A mosaic-type color filter 10 is mounted on such a solid-state image pickup element. In such a case, it is difficult to position precisely respective segments G, C and Y with light-receiving parts 5, 5... on a semiconductor substrate 1, and errors arise. However, the films 11, 11... provided on the surface of a solid-state image pickup element reflect unnecessary incident light beams, and the light incident on a channel 8 position can be prevented. Thus the photoelectric transfer in the channel 8 between the light receiving parts 5, 5... can be prevented, and the color mixing phenomenon can be eleminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a charge coupled device (CCD) type color solid-state imaging device.

(b) Prior art In recent years, development of solid-state image sensors for use in television cameras has been active, and the applicant has already developed KSANYO
TECHNICAL REVIEW VOL, 16
NO., I FEB, 1984, proposed a color solid-state imaging device in which a color filter is attached to a cross-gate solid-state imaging device employing a 7-frame transfer system.

FIG. 3(5)K is a plan view of a conventional cross-gate type solid-state imaging device, and FIG. 3(B)K is a sectional view taken along the line X--X in FIG. 3(4). As shown in these figures, in the conventional element, a partially wide portion is formed on a semiconductor substrate (1) made of P-type silicon through an insulating film (2) made of transparent silicon dioxide in an insulated state. A plurality of upper layer electrodes (3) made of polysilicon having a uniform width (81) and a plurality of lower layer electrodes (4) made of polysilicon having a uniform width are arranged orthogonally, and one of the upper layer electrodes ( These upper layer and lower layer electrodes (3)..., (4), are adjacent to the wide part (81) of 3).
The gap surrounded by . . . is configured as a light entrance window, and the portion of the semiconductor substrate il+ exposed by this entrance window is closed as a P-shaped light receiving portion (6). and,
In this case, the semiconductor substrate i11 includes upper layer electrodes (3) and
... A P-type channel stopper (6) with the substrate (1) remaining along the channel is formed, and the stopper (
6), a ten-shaped overflow drain (7) is formed extending in the central part KldN+. Each of the above electrodes between this channel stopper bar (6)..., (4)...
, a dog-N-N type channel A/ls6' is formed at the lower semiconductor substrate (1), and each of these channels /1/+81
. . . indicates a plurality of the above-mentioned light receiving parts (6
) ... is meandering. Furthermore, t91 #”i’
This is a surface protection film made of transparent glass for surface protection, covering the entire surface of the electrodes (3)..., (4)... and the exposed light-receiving part (5).

A solid-state image sensor having such a configuration has two phis, the first and the second, μ.
In order to perform interlaced driving consisting of the clock pulse generator 2 in the odd columns, the upper layer electrode (3)...K is the clock pulse generator 1 in the odd columns, and the lower layer electrode (4)...K#'i in the even columns is The upper layer electrode (3)...K is the clock pulse gate 8, and the lower layer electrode (4) in the odd row is the clock pulse gate 4.
are applied respectively. That is, as shown in the timing diagram of FIG. 4, first, the photoelectric conversion period 'l'll of the first feed ρ
In this case, while setting the clock pulse gates 1 and 8 to H level and the reverse pressure clock pulse gates 2 and 4 to L level, the bottom of the wide part (81) of each upper layer electrode (3) is For example, a potential well is formed at the channel (8) position @, O2■, ■, ■, and the light receiving part (5) position adjacent to the right or left side of this wide part (81) is ■, ■6■, ■. , ■The charge photoelectrically converted is Chan*, vfg1st f[@,
@, θ, ■, ■ are accumulated in the bottom μ wells.

Then, in the frame transfer period T12 of the next A field, the clock pulse d2. $8. By cyclically and sequentially setting f14.161 to H level,
) Both accumulated charges at position O1O move together to position (3), and both accumulated charges at positions θ and ■ move to position [F]VC#i!, and in this way the accumulated charges at two places become one place. After concentrated movement K, for example, the charge at position θ becomes a meandering chacine/l/+81 position O1@, θ, as the potential well moves.
The data is transferred sequentially as ■, ■, ■, ■.

In the next photoelectric conversion period T21 of the second feed μ,
Charge accumulation similar to that in the first feed period Tll is performed, but in the charge transfer period T22, the clock pulse G4. Da1. 2. By making feed 8 a cyclical KH level, the channel (8) position 0 becomes K , for example, the charge at position ■ is a meandering channel ρ(8) with the movement of the potential well, and position θ
, [F], ■, ■, ■ and so on.

By attaching color filters to various solid-state image sensors, they work as color solid-state image sensors.
These color filters include stripe-type filters with three primary colors that have been put into practical use for some time, and mosaic-type filters in which the three primary colors or their complementary colors are arranged in fractions in a segmented pattern, but in recent years the resolution of reproduced images has improved. Mosaic aerodynamics has become mainstream due to its high advantages.

However, if a frame transfer type solid-state image sensor K as described above is adopted, for example, a mosaic-type color filter consisting of a green segment G1 cyan segment C1 yellow segment Y as shown in FIG. 5, each segment 61C, Y is each light receiving part of the element +61
It will be arranged accordingly. Therefore, in each of the same channels lv+81, photoelectric conversion is also performed at the channel positions O, [stock], [F], and ■ under the transparent lower layer electrode made of polysilicon between the light receiving part (5)... For example, the charge generated at the position fl@, along with the charge generated at the adjacent light receiving part (6)... position ■ or ■, is transferred to the wide part (8) of the adjacent upper layer electrode (3).
1) The charge is moved and accumulated at one of the channel positions O1θ which acts as a charge accumulation section below. That is, for example, the sixth
A sectional view along channel/'+81 in the figure and the same figure (BI
As shown in the potential diagram shown in K, during the photoelectric conversion period TIK, at the light receiving part (6) of the semiconductor substrate (1), tl
! ■ is the cyan segment CK of the color filter (lO)
If the light receiving part (6) position 0 corresponds to the green segment GVC and receives green colored light, then the intermediate channel/L'18) position ■ receives cyan colored light and green colored light. Channel A/(corresponding to the 81st position and the percentage corresponding to the green color light It is distributed as shown by the arrow in the figure to both the channel (8) position θ where only charges should be accumulated.Therefore, the cyan color signal taken out from the praying element contains the green color component, and conversely, the green color signal contains the cyan color component. This has the drawback of containing color components, causing a so-called color mixture phenomenon, and deteriorating the color reproducibility of reproduced images.

(c) Problems to be Solved by the Invention The present invention has been made in view of the above-mentioned points, and aims to suppress the color mixture phenomenon in a color solid-state imaging device and obtain reproduced images with high color reproducibility. It is an object.

2) Means for Solving the Problems The cross-gate type color solid-state imaging device yIt employing the frame transfer system of the present invention has an upper layer or a lower layer extending in a direction crossing the extending direction of the channel. A light shielding means is provided at the electrode position of the electrode.

(E) Function In the color solid-state imaging device of the present invention, the light shielding means is provided at the upper layer or lower layer electrode position intersecting the extending direction of the channel. Light irradiated to channel /L/ located between the light receiving parts belonging to channel /I/ is blocked. Therefore, unnecessary charges are not generated in the channels located between the light-receiving parts, and the charges generated in the light-receiving parts corresponding to each color segment of the mosaic-type color scheme are kept busy with charges of other color components. It's bad for F1 to be mixed in.

(F) A plan view of a solid-state image sensor used in the first embodiment and (B) K the color solid-state image sensor of the present invention, and a cross-sectional view taken along the line X-in. In these figures, (1) to (8) are! J
Like the conventional device in Figure 3, the semiconductor substrate channel is shown, and the difference between the device in the same figure and the conventional device is that the lower layer electrode (
4) A light shielding film made of aluminum is placed on the surface protection film (9) at the point where the river is formed.In other words, the lower layer electrode (4) is placed directly above the lower layer electrode (4)... A light seed film of the same width (like a river extending) is applied, for example, by aluminum vapor deposition and etching treatment.

The color imaging device of the present invention can be obtained by installing a mosaic type color filter (10) as shown in FIG. 5 on a new solid-state imaging device. It is bonded to the surface of the element by the agent.

FIG. 2 shows a sectional view of the device of the present invention. According to the apparatus shown in the figure, a mosaic type color filter (10) is used in which unnecessary portions between segments are blackened or shielded from light by chrome plating or the like.

Thus, the color filter (10) is formed separately from the solid-state image sensor and is adhered to the surface of the element as described above.Each segment) G, C.

Since accurate alignment between Y and the light receiving portion (6) of the semiconductor substrate (1) is extremely difficult, there will be a considerable amount of alignment error. Therefore, even if such a light shielding means is provided and nine color filters (10) are used, the light receiving section +6) +5)...positions ■, ■.

...Channel A/(81 position ■, @, Ol...
Due to the above-mentioned alignment error, the light that has passed through the segments G, C, and Y of the color filter f101 will also be irradiated onto K, but the light shielding film (river) provided on the surface of the solid-state image sensor (11)..., this unnecessary irradiation light is reflected, and the channel zt'tg1 position■, wholesale, 0
1...K light is not incident.

In this way, according to the above embodiment, the color filter (1
0), but depending on the presence of the light shielding films (ll) (lll...)
Photoelectric conversion in the channel (8) between the two can be prevented, and the color mixing phenomenon can be eliminated.

(G) Effects of the Invention As is clear from the above description, the color solid-state imaging device of the present invention is provided with a light shield at the electrode position of the upper or lower layer electrode extending in the direction intersecting the extending direction of the channel. Since the light shielding means is equipped with a channel/vl between the light receiving parts belonging to the same channel,
C Incoming light can be blocked. Therefore, channel A/tilt at the position between the light receiving parts does not generate unnecessary charges that cause color mixing, and it is possible to obtain a high quality reproduced image with high color reproducibility.

[Brief explanation of drawings]

Figure 1 (5), (B) #'i Plan view of the solid-state image sensor used in the color solid-state image sensor used in this project, and its X-X
A line sectional view, FIG. 2 is a sectional view of the device of the present invention, a third device, (
B) is a plan view of the solid-state image sensor of the conventional device, and its X-
4 is a waveform diagram of a clock pulse, FIG. 5 is a plan view of a color filter, and FIG. 6 is a plan view of the sixth device. FIG. (ri...semiconductor substrate, (3)...upper layer electrode, (4)
... lower layer electrode, (6) ... light receiving section, (8) ... channel ρ, 00] ... color filter, (+1) ...
・Light sheet y film. Figure 2 Figure 4 [1 field!
Lai-2 fee + LLJ Figure 5 Figure 6 (A) ■ ■ OO■ (B) 00C) OOe■ O■■~523-

Claims (1)

[Claims] (1) A semiconductor substrate of one conductivity type, an insulating film formed on the semiconductor substrate, a plurality of lower layer electrodes arranged in parallel on the insulating film, and an insulated structure provided on the lower layer electrodes. A gap surrounded by a plurality of upper layer electrodes arranged in a direction crossing the arrangement direction of the lower layer electrodes is configured as a light receiving section, and the extension of either the lower layer electrode or the upper layer electrode is In the color solid-state imaging device, the color solid-state imaging device is provided with a channel for charge transfer meandering adjacent to the light-receiving section along the direction in which the light-receiving section is located, and segment-shaped color filters are disposed corresponding to each of the light-receiving sections. A color solid-state imaging device characterized in that a light shielding means is provided at the position of one of the other electrodes.