JPS60115259A - Photoelectric conversion device and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain an output signal with fidelity for optical signals by grounding a shielding film electrically to remove capacitive components yielded between an optical sensor electrode and the shielding film in photoelectric conversion device joined to a manuscript used in a transmitting side of a facsimile device and so forth. CONSTITUTION:On a transparent insulating substrate 7, Cr is evaporated in vacuum as a shielding film 8, an illumination window 12 is formed by photoetching, and glass is sputter-deposited as a transparent insulating film 9, on which a photoconductive element operating as an optical sensor 10 is selectively formed. In order to provided an electrode member for grounding the shielding film 8, one portion of the insulating film 9 is taken off, an NiCr/Au electrode 11 is formed on the optical sensor 10 by the LIFT-OFF method, and, at the same time, an electrode 18 for grounding the shielding film 8 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a photoelectric conversion device that is used as a transmitting host in a facsimile and is in close contact with a document in a size that corresponds one-to-one with the document, and a method for manufacturing the same.

Conventional structure and its problems Conventionally, as shown in Figure 1, the reading system of a facsimile transmitter uses an MO8 element manufactured using IC technology, etc.
A method is used in which an image sensor 1 such as D is used to illuminate a document 2 at a distance, and the reflected light is reduced to form an image on the image sensor 1 by a lens system 3 and photoelectrically converted. This method uses a lens system, so if the reduction ratio is large,
The optical path length from the document to the sensor is long, which is disadvantageous for downsizing the device, and the resolution at the periphery of the screen is poor and the amount of light is small.

Therefore, a close-contact image sensor was proposed in which the document and image sensor correspond one-to-one.As a result, there is no need to reduce the document image and the optical path length to the sensor can be shortened, making it possible to downsize the device. It became. As nine reading methods for a one-dimensional image sensor of the same size as the original, so-called contact type image sensor, a method using an optical fiber array (FIG. 2) and a method not using an optical fiber array (FIG. 3) have been proposed.

In the former case, image information is guided to a sensor using an optical fiber array and read, so the structure of the contact type image sensor itself is simple, incorporating only the optical sensor array. That is, as shown in FIG. 2, an LED is placed on the document 2.
This configuration includes an array 6, an optical fiber array 6, and a photoelectric conversion device 4 in one-to-one correspondence with an original.

On the other hand, the latter is a close-contact type image sensor with a built-in optical system, based on the principle that an illumination window is opened for each optical sensor element, and the light incident thereon is reflected by the surface of the document and read. In Fig. 3, 8 is a light-shielding film, 9 is a transparent insulating film, 10 is a light sensor that detects reflected light, 11 is an electrode, 12 is an illumination window, 7 is a transparent insulating substrate, and 13 is a transparent abrasive film. It is a wear layer.

Therefore, since the latter does not require any optical system such as an optical fiber, it is possible to reduce the cost and further reduce the volume of the photoelectric conversion system. Furthermore, since the optical system used is simpler than the former and has no chromatic aberration, a light transmission rate of nearly 10%, which is 2 to 3 times that of the former, can be obtained, making it possible to cope with failure in reading color originals.

On the other hand, from the perspective of manufacturing contact image sensors, contact image sensors that do not use an optical fiber array have a built-in optical system compared to those that do, so the manufacturing process is much easier. This requires precision and complicates the manufacturing process. One problem that arises is that the image sensor requires a light-shielding film 8 due to its structure, and a photoconductive element must be formed thereon.

FIG. 4 shows a cross section of a photoelectric conversion array using the structure shown in FIG. 3. The light shielding film 8 is made of vapor-deposited metal such as Cr to block all visible light, and an insulating film 9 is provided between the light sensor 10 and the light shielding film 8 to electrically insulate the light sensor 10 formed thereon. is formed. In this way, the optical sensor 10 is formed on the metal light-shielding film 8 made of a conductor with the insulating film 9 flattened, so that when the original signal is electrically extracted from the sensor, the electrode 11 of the sensor 1o It has been found that the capacitance component occurring between the light shielding films 8 made of vapor-deposited metal films poses a problem.

As shown in Fig. 4, the signals of the optical sensor section lined up with ■, ■...0, @ are read when a voltage is applied between ■ and 〇, as shown in Fig. 6. This is done by sequentially switching the optical sensor selection switch and the notch 20 in FIG. 6 from the optical sensor section (2) during the interval (between t in FIG. 6A) to output a time-series signal. In Fig. 6, 14 is a load resistance, 1
5 is the output terminal, 16 is the capacitance between the electrode 11 and the light shielding film 8, 1
9 is the input Ichikawa.

By the way, in the readout shown in FIG. 6, due to the capacitance component generated between the electrode 11 and the metal vapor deposited film (light-shielding film) 8 as described above, for the input between ■-〇 (FIG. 6A), ■- @
The output between them is as shown in FIG. 5B. That is, a capacitance component is superimposed on the signal at the beginning of the signal readout, and a higher output than the original optical signal (FIG. 6C) is sent as a signal.

Purpose of the Invention As described above, the present invention incorporates an optical system in which the capacitance component generated between the photosensor electrode and the light shielding film is removed,
It is an object of the present invention to provide a photoelectric conversion device suitable for a contact type image sensor and a method for manufacturing the same.

Structure of the Invention The present invention includes a light-shielding film having a plurality of illumination windows arranged in a line in the main scanning direction on a light-transmitting insulating substrate, and an electrode portion on the light-shielding film for electrically grounding the light-shielding film. is formed, and has photoconductive elements formed in a line in the main scanning direction on a light-transmitting electrical insulating film on a light-shielding film excluding the electrode portion, and a photoelectric conversion device suitable for manufacturing this device. A manufacturing method is provided.

Description of the Embodiment - Between the electrode 11 shown in FIG. 4, that is, between ■ and ■, as shown in FIG. are connected in parallel.

With such a configuration, the present inventors constructed @(light shielding film 8
) was attempted to be electrically grounded.

In other words, this corresponds to grounding the 0 point in Figure 6, but as a result, for an input like Figure 6 A, the output between ■ and @ will be 1 ton per month as shown in Figure 6 C. It was found that it follows the electrical input. This Jl is because by grounding the light shielding film 8, the capacitance existing between the electrode 11 of the optical sensor 10 and the light shielding film 8 is removed, and the high frequency characteristics are improved. The grounding of the light shielding film 8 is as shown in FIG.
For example, a configuration is employed in which a portion where the insulating film 9 is not formed is provided at both ends of the substrate of the photoelectric conversion device, and a ground electrode portion 18 is provided in that portion, and this electrode portion 18 is electrically grounded.

In fact, in order to realize the configuration shown in Figure 7,
Needless to say, it is necessary to consider the method of manufacturing the 'l' two-electric transformer (in the case where the conventional light-shielding film 8 is not grounded). For example, the optical sensor layer 10 formed on the light shielding film 8
When a II-Vl group compound containing Cd5-CdSe or the like as a main component is used as the photoconductive film constituting the photoconductive film, it is desirable to devise a manufacturing method with the following points in mind. I
In order to increase the ratio of the bright resistance to the dark resistance of the I-Vl group compound, these films are coated with the II-Vl group compound in an atmosphere containing vapor of a group I-group norogenide, which is a fluxing agent. The heat treatment is performed at a temperature higher than the eutectic temperature with the above-mentioned group (Ⅰ) chloride.

In most cases, the temperature during this heat treatment is 500~6o○
Because the temperature is as high as 0C and the atmosphere is extremely reactive, such as in the atmosphere of group (III) chlorides, the surface of the light shielding film 8 made of a metal vapor deposited film changes, and electrical contact is made from the surface of the light shielding film 80. You will not be able to take it. Therefore, during the heat treatment, it is necessary to protect the grounded electrode portion of the light shielding film 8 made of a metal vapor deposited film with an insulating film or the like so that it is not exposed to the halide atmosphere. To avoid this, photoeratin is used to selectively remove the insulating film 9 for forming the grounding electrode window after the heat treatment. It is desirable to carry out the process.

However, this is not the case if, for example, amorphous silicon or the like is used as the photoconductive film and the photoconductive film can be formed at high temperature without being exposed to an active atmosphere. In this case, if you mask the ground electrode forming part of the light-shielding film 8 in advance to prevent the formation of an insulating film, you can mask the ground electrode part when forming the photoconductive film, or even mask it. It can be manufactured with the material exposed.

FIG. 8 shows a method for realizing the structure of the present invention, that is, a photoelectric conversion device in which a photoconductive film is formed by performing the above-described treatment using an It-Vl group compound, and a ground wiring is provided to the light-shielding film. The manufacturing process of the device is shown. FIG. 9 shows another method for realizing the structure of the present invention, that is, a manufacturing process of a photoelectric conversion device in which a ground wiring is formed on the exposed surface of the metal light-shielding film 80 without electrically insulating it during formation of the photoconductive film. . In the apparatus shown in FIG. 8-9, the final step of forming an abrasion-resistant layer on the optical sensor is omitted.

The steps shown in FIGS. 8 and 9 will be explained below.

[1] Cr is vacuum-deposited as the light-shielding film 8 on the transparent insulating substrate 7, and the illumination window 12 is formed by photo-etching.
Figure 8 (a), Figure 9 (a).

[2] Glass is sputter-deposited as the transparent insulating film 9 [FIG. 8(b)], taking care not to affect the Cr light-shielding film 8 exposed during the formation of the photoconductive element as described above. In this case, it is advisable to mask the electrode portion of the grounded portion of the light-shielding film with a 2° mask in advance [FIG. 9(b)].

[3] After that, a photoconductive element that will become the optical sensor 10 is selectively formed on the transparent insulating film 9 using the method for manufacturing a photoelectric conversion film described above [FIGS. 8(C) and 9(C)] ) ).

[4] In order to provide an electrode part for grounding the light shielding film 8,
A part of the insulating film 9 is removed by photo-etching (Fig. 8(d)); however, as in the process shown in Fig. 9, the insulating film is sputter-deposited on the part where the grounding electrode is to be formed by masking it in advance. If not, there is no need to do so.

[6] NiC is applied to the optical sensor 10 by the lift-off method.
At the same time as forming the r/Au electrode 11, a grounding electrode 18 of the light shielding film 8 is formed [FIG. 8(C), FIG. 9(
mosquito〕.

[6] Then, a microsheet glass (not shown) is bonded onto the optical sensor for both passivation and abrasion resistance.

As described above, compared to the method of forming a photoconductive film by heat-treating the ■=Y group compound in a group ■ halogen atmosphere (Fig. 8), it is possible to form a photoconductive film by using amorphous silicon or the like to form an exposed metal film. By adopting the process of forming a photoconductive element in an inert atmosphere that does not electrically insulate the film surface (Figure 9), the process of opening a window in the transparent insulating film at the electrode part of the light-shielding film grounding can be omitted. , the light-shielding film can be easily grounded, and productivity can be further improved.

FIG. 10 shows the effect when the light shielding film 8 of the photoelectric conversion device of the type shown in FIG. 3 is grounded. The steady state output of each optical sensor depends on the sensitivity of the optical sensor. If there is almost no variation in the sensitivity of each photosensor and there is no light shielding film under the photosensor, irradiation with light at a constant illuminance will cause
When pulsed at about kHz, the output is flat as shown in FIG. 10(b). However, if there is a light-shielding film under the optical sensor and it is driven under the same conditions as above, the 10th
As shown in the figure (-), the original optical signal x exhibits a high output because the capacitance components existing in the electrode of the optical sensor and the light-shielding film are superimposed on the first few bits.

Therefore, by grounding the light shielding film 8 as in the present invention, the above-mentioned capacitance component could be removed, and an output signal faithful to the optical signal as shown in FIG. 10(b) could be obtained again.

Effects of the Invention According to the present invention, the capacitance component generated between the optical sensor electrode and the light-shielding film can be removed, and an output signal faithful to the optical signal can be obtained, which is a special effect for a photoelectric conversion device for reading originals, etc. This will greatly contribute to the realization of compact, high-performance photoelectric conversion devices.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the reading υ system of a facsimile transmitter when using an IC image sensor, and Figure 2 is a one-to-one diagram of the reading system of a facsimile transmitter using an IC image sensor.
A schematic diagram of the reading system of a facsimile transmitter (one that uses an optical fiber array) when using an image sensor compatible with Figure 4 is a cross-sectional view of the main parts of a photoelectric conversion device using the structure shown in Figure 3. , Cr light-shielding film force; An explanatory diagram of the voltage response of the optical sensor in a certain case, FIG. 6 is a signal input/output equivalent circuit diagram of each optical sensor in the device of FIG. 3, and FIG. 7 is an example of the present invention. Partially enlarged views of the photoelectric conversion device, FIGS. 8(a) to 8(e) show It-V as a photoconductive element.
Cross-sectional views of the manufacturing process of a photoelectric conversion device according to an MM example of the present invention when using a Group I compound, No. 91QI (a) to (d)
10(a) and 10(b) are cross-sectional views of the manufacturing process of a photoelectric conversion device according to another embodiment of the A/invention in which a photoconductive element that can be formed at a low temperature is used. It is a figure showing a comparison. 7... Transparent insulating substrate, 8... Light shielding film,
9... Transparent insulating film, 1o... Optical sensor, 11... Electrode, 12... Lighting window, 13
......transparent surface" wear layer, 14...1'↓load resistance, 16...output end, 18...ground type (ψ(i'τIS1゜Name of agent Patent attorney Toshio Nakao and one other person Figure 1 Figure 2 Figure 4 Figure 3 Figure 4 Figure 5 σ ρlAS Vision Figure 6 Figure 7 Figure 9 Figure 72.7 Figure 10 6 ″ ′ bi′1,7F N/. tanoji io /6 ji゛, v FIV. Continued from page 1 of 2 0 Inventor Noboru Yamagami 0 Inventor Masaru Ohno

Claims (1)

Scope of Claims: (1) A light-shielding film having a plurality of illumination windows arranged in the main scanning direction on a transparent insulating substrate, and a light-shielding film formed on the light-shielding film and electrically grounding the light-shielding film. a light-transmitting electrical insulating film formed on the light-shielding film excluding the electrode part, a photoconductive element formed on the insulating film in the main scanning direction, and a light-transmitting electric insulating film formed on the photoconductive element. What is claimed is: 1. A photoelectric conversion device comprising: an electrode; (Wholesale) A step of forming a light-shielding film on a light-transmitting insulating substrate, a step of forming a transparent insulating film on the light-transmitting film, and a step of depositing an 11-Vl compound on the insulating film by vacuum evaporation method, In an atmosphere containing a vapor of a Group 11 halide,
A step of forming a photoconductive element by performing heat treatment at a temperature higher than the eutectic temperature of the I-Vl group compound and the group II halide, and forming the transparent insulating film in order to provide a grounded electrode portion of the light shielding film. Manufacturing a photoelectric conversion device characterized by comprising a step of selectively removing the light shielding film to expose a portion of the light shielding film, and a step of forming a ground electrode of the light shielding film at the same time as forming an electrode of the photoconductive element. Method. (3) forming a light-shielding film on the light-transmitting insulating substrate; forming a transparent insulating film on the light-shielding film except for an electrode portion for electrically grounding the light-shielding film; and A step of forming a photoconductive element on the P, It 11%, 1: without electrically insulating the surface of the light-shielding film on which no film is formed, and simultaneously forming an electrode of the photoconductive element. 1. A method for manufacturing an electrical conversion device, characterized by comprising a step of forming a ground type +@ of a light shielding film.