JPS58216459A - Photoelectric converter and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a photoelectric converter in which a defect such as scratch, dirt or stepwise disconnection of a photoconductive film is not produced but good characteristics are provided by depositing the photoconductive film with a metal mask, heat treating it for activation without isolating the film, employing a resist film such as photovarnish which is used at the etching time to protect each process and the etching step as a final step. CONSTITUTION:Photoconductive films 22, 22' are deposited in a strip shape on a glass substrate 21 in a main scanning direction with a metal mask 23, the substrate 21, on which the film 22 is formed, is removed from a depositing device, and an activating step is immediately performed in a clean state. A positive resist is coated on the entire surface, only a part to be attached with an electrode is exposed, and the resist is removed. Subsequently, an electrode NiCr, Au are entirely deposited, and dipped in an acetone. The NiCr, Au on the part, on which the resist remains, are isolated from the substrate due to the solution of the resist, thereby forming common electrode 24 and individual electrodes 24' which have desired electrode pattern. Eventually, the part 25 between the photoreceptor and the electrode 24' and the part 26 between the blocks of the electrode 24 are dry etched with the photoresist as a mask so as to isolate the strip film 22 into each bit.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an original document and a
The present invention relates to a photoelectric conversion device of a size corresponding to No. 1 and a method of manufacturing the same.

2. Description of the Related Art A photoelectric conversion device such as an optical sensor array having photoelectric conversion characteristics is used as a document reading device on the sending side of a facsimile. The structure and manufacturing method of a conventional photoelectric conversion device of this type are shown in Figures 1 (IL) to (
d) and shown in FIG. Figure 1 (IL) ~ (d) r/
'i is a partially enlarged view in the sub-scanning direction, and FIG. 2 is an enlarged top view. In Figures 1 and 2, a photoconductive film 2 such as 0dd-Cd's is first deposited on the entire surface of a glass substrate 1, etc. (Figure 1(a)), and then, for example, in the case of 8 mm, the width is After forming a rectangular resist pattern 3 of 85 μm and 350 μm length aligned in a line in the main scanning direction, etching is performed using an etching solution such as bromine to form island-shaped photoconductive film groups along the resist pattern. (Fig. 1(b)). At this time, the resist pattern 3 remains on the top of each photoconductive film 2, so the entire glass substrate is immersed in a remover or the like to remove the resist (Fig. 1(b)). (Figure 1 (C)).The glass substrate, on which island-shaped photoconductive films arranged in a line in the main scanning direction are formed, is coated with Cd halide (for example, a small amount of cac7B powder). In an atmosphere containing one or more types of vapor, heat treatment is performed at a temperature higher than the eutectic temperature of cas-cas and halogenide, for example, at a temperature of 500 to 6oO°C, to impart a sensitizing effect.Next, sensitization is performed. Corresponding to the island-shaped photoconductive film group having an effect, a common electrode group 4 connected in common in a certain number of units and an individual electrode group 4' grouped in a certain number of units are formed by a lift-off method. (FIG. 1(d)).Furthermore, 5.6 film leads are bonded to the individual electrode group 4' at the connecting portion 7 to form a matrix connection to form an individual electrode side extraction terminal.

Next, as shown in FIG. 3, a photoelectric conversion device 8 obtained by the above method and an illumination light source 9. selfoc lens array 1
0. From the transmission original 11 arranged as shown in the figure and illuminated by the illumination light source 9. Wow. Ya rLy 7k
An image is formed on the photoelectric conversion device 8 at 1, 2□, a, -4°, and extracted as an electrical signal.

However, the structure and manufacturing method of the photoelectric conversion device as described above has the problem that variations in output characteristics tend to occur for the following reasons.

First of all, in the process from FIG. 1(b) to FIG. 1(C), it is difficult to completely remove the resist pattern 3 on the top of the photoconductive film 2. For example, for reading A4 size manuscripts, with a resolution of 8 lines/am.
In this case, such islands of the photoconductive film 2 are arranged in a line in the main scanning direction of 1728 bits. The fact that the total number of bits is large is a real problem, but the fact that they are lined up in rows makes it even more difficult. Remains of resist pattern 3 are observed with probability. If even one bit of such a thing exists, it will be exposed to high temperature treatment in the subsequent activation process, which will affect the characteristics, and there is a very high probability that it will become defective. In FIG. 1 (IL) and FIG. 1(b), the photoconductive film 2 is etched by a wet method, a dry method, or a combination of both.
In the case of a5-Cd's, bromine is used as an etching solution in wet etching, but the surface of the resist 3 that comes into contact with bromine changes in quality, becomes difficult to dissolve in the resist removal solution remover, and remains as the aforementioned resist residue. It becomes easier. In the case of dry etching, the same is true in that when the surface of the resist 3 is hit with N2 and 02 ions, it becomes 7 and can be dissolved in the remover. Furthermore, even if a dry etching method such as 02 plasma is used instead of a wet resist removal method such as a resist remover, due to the large area, residual materials will be observed to varying degrees, which may affect the characteristics. The probability of it becoming defective is very high.

Second, there is a problem that the electrodes are broken due to the thickness of the photoconductive film 2. That is, the electrode group 4, 4' shown in FIG. 1(d)
In the process of forming 12 and 1 as shown in FIG.
A break occurs at the 2' portion. The thickness of the photoconductive film 2 is generally about 3,000 to 10,000 A, whereas it is desirable to make the electrode thinner due to strain etc., and the thickness is often less than 1,000 A. , 12'
If the electrode is attached to the surface, breakage will occur more easily. This is the first
This is because, as is clear from FIG. 1(b), the ends 12, 12' of the photoconductive film 2 in the sub-scanning direction are formed by etching and are not tapered forward but vertical.

Thirdly, as shown in FIG. 1(0), after separating the photoconductive film 2 into island shapes, if an activation treatment is performed at 6r) 0'C to 600°C, the glass substrate 1 (e.g. corning finished o59
) shrinkage occurs, and the pitch of the island-shaped photoconductive film 2 in the main scanning direction becomes smaller, causing a problem in which it no longer matches the pinch of the next electrode pattern.

Therefore, at present, before attaching the photoconductive film 2, the glass substrate 1
A method is used in which the material is heat-treated at a temperature of eoo°C or higher and shrunk in advance.

However, in reality, even if such heat treatment is performed in advance, further shrinkage occurs during the activation process, and pitch deviations cannot be completely eliminated. Furthermore, since the heat treatment process is increased, the probability that the surface of the glass substrate becomes contaminated increases.

The fourth problem is that the adhesion between the photoconductor film 2 and the glass substrate 1 is generally poor. Therefore, in the process of etching into islands and removing the upper resist with a remover as shown in FIG. 1(b) and FIG. 1(C), the island-shaped photoconductive film 2 peels off and flows. There is a very high chance that it will get lost.

Therefore, in reality, before applying the etching resist, that is, immediately after applying the photoelectric film 2, annealing is performed at 400° C. or higher to improve adhesion. Such a method not only increases the number of steps but also increases the probability of contamination. In the case of a photoconductive device used as a large line sensor as in the present application, such a problem greatly affects the yield reduction.

Fifth, instead of forming the electrode by the lift-off method described above and immediately bonding the film lead,
Actually annealing during that time.

Processes such as observation, measurement, repair, and passivation are included. That is, since various processes and handling are required before passivation is performed, there is a possibility that the light-receiving surface of the photoconductive film may be scraped and smeared, even though it is extremely light and extremely small. 0 (18-8e) The thin film is mechanically weak and the surface is very easily scratched.Even the slightest scratches, which can be seen even by microscopic observation, cause a decrease in output.
There is a high probability of experiencing becoming bitdown.

The present invention is intended to solve the above-mentioned conventional problems, and the biggest problem with photoelectric conversion devices used on the sending side of facsimile machines, whose size corresponds 1:1 to the original document, is the reduction in yield. It is an object of the present invention to provide a structure and a manufacturing method thereof for eliminating factors that cause variations in output characteristics.

Examples of the photoelectric conversion device and its manufacturing method of the present invention will be described in detail below.

Mass, size 230″IrIL×60r′″-, thickness +1
．． Thoroughly wash the 2mm Corning 7059 glass substrate.
dry. After that, without going through the high kneeling process of 6oO0C or more to prevent pitch deviation as in the past,
Immediately a photoconductive film, for example a Cd5-Ca5e solid solution, is deposited on the glass substrate by vacuum evaporation or sputtering. In this case, instead of depositing on the entire surface, a metal mask is used to deposit the glass substrate 2 as shown in FIG.
1, a photoconductive film 22.2'2' is deposited in a strip shape in the main scanning direction. The reason why the photoconductive films 22 and 22' are formed on both sides of the glass substrate 21 in FIG. 5 is to obtain two sensors from one glass substrate 21, and in the last step, half of the I try to divide it into Figure 6 is the 5th
This is a partially enlarged cross-sectional view in the sub-scanning direction of the figure, showing the metal mask 23.
This shows how a Cd5-(jdse photoconductive film 22 is evaporated using a Cd5-(jdse). As is clear from FIG.
It adheres to areas adjacent to the metal mask 23 and separates. Therefore, the end portion of the deposited photoconductive film 22 in the sub-scanning direction is thin and tapered as shown by the dotted line.

Next, use resist to etch as before.

The glass substrate 21 on which the photoconductive film 22 is formed is taken out from the vapor deposition apparatus without going through a process such as resist removal, and immediately enters the activation process in a clean state. Activation means heat treatment at 600 to 600°C in a CdC112 atmosphere. This treatment makes the photoconductive film 22 more sensitive and also improves the adhesion between the glass substrate 21 and the photoconductive film 22.

Thereafter, in order to form electrodes by a lift-off method, for example, a positive resist is applied to the entire surface, only the portion where the electrodes are to be attached is exposed, and the resist is removed.

Next, electrode (iicr) and Au are deposited on the entire surface, and then immersed in acetone. NiCr on the remaining part of the resist
, Au is released from the glass substrate by dissolving the resist, and a common electrode 241 and individual electrodes 24' having a desired electrode pattern as shown in FIG. 7 are formed. In FIG. 7, 22 is a photoconductive film.

Finally, in order to separate the strip-shaped photoconductive film 22 into each bit as shown in FIG.
6 and the portion 26 between the blocks of the common electrode 24 are dry or wet etched using a photoresist as a mask. When dry etching is employed, the photoresist used as a mask does not need to be removed after etching. In that case, if a polyimide resin Photonyce (manufactured by Toyo Rayon) is used as the photoresist, it will show a better passivation effect. It has been certified. Regarding the point that there is no need to remove the photoresist, for example, referring to FIG. 1, the incidence of light is as follows.
Since the passivation material is applied from the second main surface, that is, the back surface, of the substrate 1, the passivation material placed on the photoconductive film 2 and the electrodes 4,4' on the first main surface, that is, the front surface, does not need to be transparent. Therefore, in the case of the present invention, there is no need to remove the resist, and the resist can be used for protection, so there is no need to worry about bit down caused by incomplete removal of the resist after etching as in the prior art.

Of course, the above-mentioned protective resist is only attached to the surface, not the sides, so it is natural that in the end it will be necessary to apply a passivation agent such as photonis over the entire surface. .

On the other hand, wet etching can also be performed.
□ Yes, but in this case, bromine will be used as the etching solution, so the resist etc. after etching will contain bromine, which must be removed. If not removed, residual bromine will adversely affect the photoconductive film 22,
Reliability deteriorates. Therefore, in the case of wet etching, a resist removal process is required after etching.

This completes the -core leading conductive film, the common electrode 9, and the individual electrodes, but it is often necessary to perform further heat treatment to stabilize the characteristics.

Next, as in the conventional example, as shown in FIG. 2, using a film lead in which a copper foil wiring 6 is formed on a polyimide film 6, bonding is performed with the lower layer wiring 4 at a portion 7 in FIG. Connect the wires in a matrix and use them as individual electrode side extraction terminals.

In the above process, the activation process may be started immediately after evaporating 06B-Case, but the glass substrate and Cd5-C
400-600 °C before activation, not for the adhesion of a5e, but to improve the crystallinity of cas-OdSe.
It is preferable to perform annealing at

24. In the etching process for forming the individual electrodes 24', a portion 26' of the common electrode portion may be cut as shown in FIG. In reality, various shapes may be used depending on mask alignment accuracy, etc., but in practice, it is sufficient to cut as shown in FIG. 8.

The biggest problem with large line sensors is that it is extremely difficult to match the output characteristics of all bits, making it difficult to improve yield. The structure of the photoelectric conversion device and the manufacturing method thereof according to the embodiment of the present invention are as described above,
This makes it possible to improve the yield by making the output characteristics uniform from the following viewpoints. That is, according to the method for manufacturing a photoelectric conversion device according to the embodiment of the present invention, the activation step is started immediately after the photoconductive film is deposited, so there is almost no contamination before activation, and the biggest cause of output variation is eliminated. removed.

Further, as shown in FIG. 6, for example, by vapor deposition using a metal mask, the cross-sectional shape M in the sub-scanning direction becomes a forward taper, and the electrode stages as shown in FIG. Since the heat treatment for activation is performed without separating the film, there is no need to worry about pinch misalignment between the island-shaped photoconductive film group and the electrode pattern due to shrinkage of the substrate as a result of heat treatment. There is no need for a second cleaning after heat treatment and preheat treatment, and the photoconductive film can be deposited immediately after the first cleaning. Therefore, the number of steps is reduced, the probability of contamination of the glass substrate surface is reduced, output variation is reduced, yield is improved, and costs are reduced. In addition, even after heat treatment, there is no pitch deviation that still occurs, and output variations due to pitch deviation are also eliminated.

In addition, according to the present invention, before starting the ethoching process that requires adhesion between the glass substrate and the photoconductive film, unlike the conventional method,
Since the activation process is performed to increase adhesion, there is no need for a heat treatment process to increase adhesion. This not only reduces the number of steps but also reduces contamination on the substrate surface, leading to improved yields.

However, in some cases, conventional annealing may be performed before the activation process, not to improve adhesion, but to improve binding, but complete adhesion cannot be achieved with annealing alone. In many cases, in the case of the present invention, an activation step is performed before etching Cd5-Cd5e, so the problem of adhesion is completely eliminated.

Furthermore, after electrode formation by lift-off, annealing and observation before passivation.

In each process such as measurement and repair, bit down due to extremely slight scratches during handling.
In the case of the present invention, there is no need to worry about the occurrence of this problem because the resist film, such as photo-neath, used during etching is used as it is for protection.

Furthermore, by using the resist after dry etching as a protective film, it is possible to avoid the errors of resist removal, and solve the problem of numerous bitdowns caused by incompleteness of resist/removal. I can do it. That is, Cd5-1°Cd
's etching is brought to the final step, eliminating the need for resist removal and reducing bit down (bit down).
down) It will be a car that drastically reduces the causes of occurrence.

Furthermore, since it uses the Cd5-j method (in which the electrodes are cut at the same time during the dry etching of idse), it also has the feature that defects due to thin coating can be reduced.

As explained above, the method for manufacturing a photoelectric conversion device of the present invention does not cause defects such as step breaks in the photoconductive film, and the photoelectric conversion device obtained exhibits good characteristics and has industrial utility value. is high.

[Brief explanation of the drawing]

Figures 1 (2L) to (C1'l) are cross-sectional views at each step of the conventional method for manufacturing a photoelectric conversion device, Figure 2 is a partially enlarged top view of the photoelectric conversion device shown in Figure 1, and Figure 3 is a photoelectric conversion device. A schematic layout diagram when using the conversion device as a document reading sensor,
FIG. 4 is a diagram showing how electrodes are separated in a conventional photoelectric conversion device, and FIG. 6 is a diagram showing how a photoconductive film is deposited on a glass substrate in the method for manufacturing a photoelectric conversion device according to an embodiment of the present invention. FIG. 6 is a partial enlarged view of the top surface, in which a metal mask is used in the method for manufacturing the photoelectric conversion device 4 according to the embodiment of the present invention.
Partial enlarged view in the sub-scanning direction when depositing a photoconductive film, No. 7
The figure is a partially enlarged top view showing how electrodes are formed on a photoconductive film in the method for manufacturing a photoelectric conversion device according to an embodiment of the present invention;
FIG. 8 is a partially enlarged top view showing the removal of the photoconductive film in the light-receiving section and the areas between the individual electrodes and between the common electrodes in the manufacturing method of the photoelectric conversion device according to the embodiment of the present invention, and FIG. 9 is the light-receiving part. FIG. 6 is a partially enlarged top view of a photoelectric conversion device according to another embodiment of the present invention in which the photoconductive film is removed between the individual electrodes and between the common electrodes. 1.21...Glass substrate, 2.22...
・Photoconductive film, 4, 24... Common electrode, 4'...
...Individual electrode. Name of agent: Patent attorney Uneo Nakao and 1 other person No. 1
figure? Figure 2 Figure 3 Figure 1 Figure 4 Figure 5 Figure 2 Figure 7 Figure 8

Claims (1)

[Scope of Claims] (1) A light-transmitting insulating substrate, a group of island-shaped photoconductive films having a tapered cross-sectional shape at the end in the sub-scanning direction and arranged in a line in the main-scanning direction, and the photoconductive film The groups are grouped into a certain number of units, and each group consists of a common electrode group in which one terminal of the photoconductive film is connected in common, and an individual electrode group connected to the other end of the photoconductive film. Features of photoelectric conversion device. (2) Claim 1, characterized in that a photoresist film is provided as a surface protective film on the photoconductive film.
The photoelectric conversion device described in . (3) The photoelectric conversion device according to claim 2, wherein the photoresist film is a polyimide photosensitive resin. (4) forming a photoconductive film in a strip shape in the main scanning direction on a transparent insulating substrate by vacuum evaporation or sputtering using a mask; and a heat treatment process for activating the photoconductive film; a step of grouping a plurality of individual electrode groups arranged in a line in the main scanning direction into a certain number of units, forming a common electrode facing the individual electrodes for each group, and applying the photoconductive film to the electrode group. 1. A method for manufacturing a photoelectric conversion device, comprising the step of separating each one according to the phase of the photoelectric conversion device. (6) The photoconductive film is a ■-■ compound, and the heat treatment step is carried out at a temperature equal to or higher than the eutectic temperature of the ■-■ group and the Cd halide in an atmosphere containing vapor of one or more types of CD halides. A method for manufacturing a photoelectric conversion device according to claim 4, characterized in that the method is carried out by: (6) The step of separating the photoconductive film is a step of individually separating the photoconductive film by dry etching in accordance with the phase of the electrode group using a photoresist pattern. A method for manufacturing a photoelectric conversion device.