JPS58142567A - Manufacture of image reading element - Google Patents

Abstract

PURPOSE:To relax the restriction in selecting the material of an electrode and thus contrive the improvement of the yield by a method wherein SnO2 or ITO, etc. is determined as the material of an opposed electrode, and a metallic electrode is arranged at the part of connection to the external electrode or junction to the switching element. CONSTITUTION:SnO2 is evaporated on a glass substrate and etched using flon, and accordingly the patterns of a common electrode 7 and discrete electrodes 8 are formed. CdSe 3 is evaporated and heat-treated at 600 deg.C in a small amount of O2. At this temperature, the SnO2 is sufficiently stable, and the photoconductivity characteristic of the CdSe does not vary. The CdSe 3 is etched by the mixed solution of nitric acid and phosphoric acid resulting in the formation of sensor elements 3. Next, Cr and Au are successively evaporated and laminated on a part of the common electrode 7 and the discrete electrode 8 by using a mask, and a patterning is performed, accordingly electrodes 5 and 6 are provided. By this constitution, the restriction in selecting the material of an electrode for the CdSe of extremely bad chemical resistance or the compound with it as the base material can be relaxed, and therefore an image reading element can be formed with good yield.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides cadoncum selenide (Cd8.) or Cd8.
The present invention relates to a method of manufacturing a good image reading element O using d8 as a base material and a photoconductive film as a sensor material.

A circular image reading device using a photoconductive film as a sensor is a general K11II device, that is, a device for converting image data into electrical signals by changing the resistance of the photoconductive film in response to optical information. The sensor element portion of this device is formed by arranging a plurality of opposing electrode pairs in accordance with a desired WFI degree and connecting the opposing electrodes with a leading thin film. An example of the circuit configuration is shown in FIG. 1, in which 1 is a DC power supply, 2 is a load resistor, 31 to 3m are leading low film sensor plays, and 41 to 4n are switching element arrays. The reflected light from the original is introduced onto the light guiding low film seven sensor arrays 31 to 3n through a cell phototer lens, optical fiber, etc.

By sequentially switching the switches 41 to 4n and reading the resistance of the photoconductive film, optical information can be read out in chronological order. An example is shown in which one side of the electrode pair is connected in common.

FIG. 2 is an example of a pattern configuration around the sensor element having the configuration shown in FIG. Reference numeral 5 designates nine common electrodes that commonly connect one side of a plurality of opposing electrode pairs, and 61 to 6fi designate individual electrodes that individually oppose the common electrode 5. That is, the common electrode 5 and the individual electrodes 61 to 6110 form a plurality of pairs of opposing electrodes, and these patterns are formed by ordinary thin film processes such as vapor deposition, sputtering, and photoetching. It is formed.

Cd8・ or a compound having Cd8・ as a base material, such as Cd8* 1-1Tex, Cd8* 1-(sX,
As for its physical properties, it has high charging conductivity and can be easily formed into a thin film by vapor deposition or sputtering, making it suitable as a moonlight conductive film for image reading P elements.

However, on the other hand, by vapor deposition or sputtering! I shadow formation 90d
8 or Cd8 as the base material, the compound thin film is.

If the crystallinity is poor (1), activation by heat treatment at 500 to 600°C is necessary to obtain sufficient characteristics as an image reading element. It has poor chemical resistance (it has the drawback of being a stone and being corroded by most etching solutions that corrode metal electrodes).

When using Cd8 or a compound thin film based on Cd8 as a light guide layer to form a ii*gun*sho element, the 1111i temperature treatment of photoconductor II is required as in the case of light guide. However, regardless of whether the metal thin film normally used as an electrode material has a single-layer or multilayer structure, oxidation, solid phase diffusion, peeling, etc. occur at the processing temperature of the light guide film (500 to 600°C), making it difficult to use as an electrode material. At the same time, the function and characteristics cannot be maintained, and at the same time surface reactions such as diffusion occur at the interface with the light guide layer, making it impossible to maintain the properties of the light guide layer. Therefore, when using a metal thin film as the material for the counter electrode, it is necessary to XX/
An example of the cross section is shown in FIG. 3, where 3 is a light guide thin film made of a compound thin film with Cd8 or CdSe as a base material;
is a common electrode, and 6 is an individual electrode.

Normally, the gap between the common electrode 5 and the individual electrodes 60 is required to be 10 to 100 sm and 11 degrees, which increases the resolution of image reading. This value is in a range that cannot be controlled by nine-mask evaporation using a metal misfaction force). is Cd8・
Compound thin films with .

Chemical resistance is extremely poor and materials such as An, Au, Co, Ni, Me, W, and Cr, which are usually used as electrode materials, have extremely poor chemical resistance.
) It is also corroded by the etching solution for gold 11. For these reasons, there are many restrictions on the selection of electrode materials, and it is necessary to have a degree of freedom in selecting materials that satisfy various requirements, such as connection to an external circuit or bonding of switching elements.

On the other hand, the lift-off method is a rounding method in which a metal layer is formed on a photoresist, and then the resist is removed.
Due to constraints in the resist stripping process, the resist hardening temperature (~
The metal film must be formed at a temperature of 150° C. or lower, and it is difficult to obtain sufficient adhesion to the substrate, resulting in a decrease in yield and reliability.

It is an object of the present invention to provide a method for manufacturing an image reading element that is free from such limitations in electrode material selection, yield loss, and reliability.

That is, transparent conductive films such as tin oxide (8n02) and indium tin oxide (ITo) are sufficiently stable even at low heat treatment temperatures (500 to 600°C) for photoconductivity), and Cd
Compound thin film O with 8e or edge as the base material does not deteriorate the light conductivity properties.Therefore, these transparent conductive films are used as the counter electrode material, and the parts require connection with external electrodes or bonding with switching elements. For this purpose, a configuration in which metal electrodes are wired may be used.

FIG. 4 shows an example of the configuration of a cross section of the element part according to the present invention [X-X', 3 is a light guiding low film whose base material is Cd8a or Cd8e, and 5 and 6 are common electrodes formed of metal thin films. and individual electrodes, and 7.8 is a round common electrode and individual electrodes formed of a transparent conductive film.

The present invention will be explained below with reference to the embodiments shown in FIGS. 5(1) to 5(d).

First, on a glass substrate (by vapor deposition, p5n021 [0.
3βm is formed, and dry etching is performed using 70-12 gas to obtain a pattern of the common electrode 7 and individual electrodes 81 to 8n (FIG. 5(a)). Next, Cd8e@3 is formed on the electrodes. Cd'
In this case, 5nOzal showed no deterioration even after heat treatment at 600°C, and also had a negative effect on the light conductivity characteristics of the edge film 3. I won't give it.

Next, Cd8ei[3 is etched to form sensor element parts 31 to 3n (FIG. 5(C)). The etching solution may be a mixture of nitric acid and phosphoric acid.
Either of the heat treatment and etching steps for Cd8el[3 may be performed first.

Thereafter, a shape is formed in which the Cd8a@3 is not deposited on the sensor element parts 31 to 3n formed of Cd8a@3, but is deposited on a part of the common electrode 7 and individual electrodes 81 to 8n formed of a transparent conductive film. Using a vapor deposition mask, metal electrode materials 1 such as 0.1 μm Cr and AIIIJEII are sequentially vapor-deposited and laminated, and etched in a desired pattern to form electrodes 5.
, 6146-alllF is formed (Fig. 5(d)),
Here, it is important not to deposit the metal electrode material on Cd8e1[3. That is, Cd8@II
If there is no metal on 3 (because of this, when etching the metal layer to form an electrode, the Cd8 film 3 is
This is because it can preserve the food.

By employing the manufacturing method described above, in the present invention, restrictions on the selection of electrode materials are greatly eased, and it becomes possible to freely (select) metal materials having required characteristics.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of one element of a conventional image reading device. Figure 2 is a diagram of the pattern configuration of Figure 1, and Figure 3 is a diagram cut along line X-X/ of Figure 2. Cross-sectional view at 9 o'clock, Figure 4 is the 3rd
A cross-sectional view of the sensor element portion of the present invention shown corresponding to the figure,
FIGS. 5(a) to 5(d) are plan views of a nine-manufacturing factory for explaining the present invention in detail. 3... Light guiding low film, 5... Nine common electrodes made of a metal thin film, 6... Nine individual electrodes made of a metal thin film, 7... Round common electrode made of a transparent conductive film, 8... ...Individual electrodes made of transparent conductive film. 1st evil figure 2 figure 3 figure 7? Figure 5?

Claims (1)

[Claims] The first step is to form a plurality of opposing electrode pairs made of a transparent conductive film on an insulating substrate, and a step of forming a selenide cadmium conductor (Cd8.) or Cd8. as a base material so as to connect the opposing electrodes. a second step of forming a photoconductive film; a third step of heat-treating the photoconductive film; and a third step of heat-treating the photoconductive film; A fourth step of depositing a metal layer using a master having a shape in which the metal layer is attached to a part of the round common electrode and the individual electrodes, and etching this metal layer into the desired butter 7, The manufacturing method of the device is timely and consists of the step of forming a metal electrode.