JPH0673373B2 - Method of manufacturing contact type one-dimensional image element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention is provided with a II-VI group compound semiconductor containing Cd or a photoconductive material containing two or more kinds of these compound semiconductors as a photoelectric conversion film. The present invention relates to a method for manufacturing a contact type one-dimensional image device that employs a pattern reading method and matrix wiring driving.

<Prior Art> As a method for producing a long or large-area photoelectric conversion film, a thin film production technique such as a vacuum vapor deposition method, a sputtering method or a glow discharge vapor deposition method has been conventionally used.

Further, in order to improve the environment resistance of an element using a photoelectric conversion film manufactured by using such a thin film manufacturing technique, the photoelectric conversion film is protected by various organic resin films or inorganic insulating films.

<Problems to be Solved by the Invention> In the above-described conventional thin film manufacturing technique, the quality of the film characteristics depends largely on the manufacturing technique of the manufacturing apparatus, and there are problems in yield and reliability. For example, when an amorphous silicon thin film is formed by the reactive sputtering method or the glow discharge vapor phase growth method, it is difficult to obtain the reproducibility and the uniformity of the film characteristics because the advanced technology is required to control the glow discharge plasma. Becomes

Further, when a II-VI group compound semiconductor thin film containing Cd is produced by a sputtering method, a vacuum deposition method, or the like, the deviation from the stoichiometric composition slightly changes depending on the production conditions, and the photoconductivity Therefore, the activation treatment by doping with a halogen compound such as Cd, Cu, or Ag also has a major drawback that it is difficult to obtain reproducibility depending on the manufacturing conditions.

Further, in the conventional element manufacturing method, an additional process for forming a protective film for the element is required, which causes a problem such as an increase in cost.

The present invention was created in view of these points,
It is an object of the present invention to provide a method for manufacturing a contact type one-dimensional image device, which simplifies the process of manufacturing the device and improves the yield of device manufacturing.

<Means for Solving the Problems> In order to achieve the above object, the method for producing a contact type one-dimensional image device of the present invention comprises a Cd-containing II-VI group compound semiconductor single substance or two or more of these. In a contact type one-dimensional image device in which a light receiving element composed of a compound semiconductor and a matrix wiring section are provided on the same substrate, an interlayer insulating layer for forming a matrix wiring is formed so as to cover the light receiving element section. I am configuring.

<Operation> As described above, in the present invention, by manufacturing a light receiving element composed of a II-VI group compound semiconductor containing Cd or a compound semiconductor of two or more kinds of these on the same substrate as the matrix wiring forming portion, Since the interlayer insulating film for forming the matrix wiring also serves as a protective film for the photoelectric conversion film forming the light receiving element at the same time, the manufacturing process of the element is simplified, and as an example, the interlayer insulating film is formed. By using the insulating polymer film as the film, defects due to the generation of pinholes in the protective film and the interlayer insulating film can be reduced as much as possible, and the yield of device fabrication can be improved.

By the device manufacturing process of the present invention described above, the protective film forming process of the photoelectric conversion film is completed at the beginning of the device manufacturing process by forming the interlayer insulating film for forming the multi-layer wiring. It is possible to completely eliminate the influence of various etchants on the light-receiving element characteristics in the processing steps, etc., and it is possible to greatly improve the reliability of the element characteristics.

In addition, since the organic polymer material has a smaller dielectric constant than the inorganic insulating material and a thick film of 5 to 10 μm can be easily formed, the insulating polymer film should be used as the interlayer insulating film as in the embodiment. As a result, it is possible to reduce the capacitance of the multilayer wiring portion, and it is possible to form a matrix wiring that does not hinder the high speed driving of the device. Furthermore, since a thick film that is difficult to form with an inorganic insulating material can be easily formed with an organic polymer material, it is easy to prevent pinholes from occurring, and the yield of device fabrication is improved and the cost is reduced.

<Example> Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

II-VI group compound semiconductor containing Cd or 2 of these
The compound semiconductor material of one kind or more may be Cucl ₂ and / or CuCl ₂ and / or a raw powder of about 0.2 μm obtained by a known chemical extrusion method.
A material to which photoconductivity is imparted is used by adding 0.1 to 1 mol% of AgCl ₂ as an impurity and firing it in an inert gas at 600 to 800 ° C. for 30 to 60 minutes for activation. This crystal powder is used as a starting material used in the following examples.

The element structure is shown in FIG. 1 and FIG. 2 (AA 'sectional view in FIG. 1).
As shown in FIG. 2, the photoelectric conversion film 2 formed on the insulating substrate 1 through the firing process is provided in a strip shape, and the common electrode 3 and the striped individual electrode 4 are provided so as to cover both sides of the photoelectric conversion film 2. This individual electrode 4 is continuously extended to form a lower layer wiring 5, an organic insulating layer 6 serving as an interlayer insulating film and an element protective film is formed thereon, and an upper wiring 7 is further formed thereon. The electrode wiring is formed as a matrix wiring divided into a plurality of blocks.

The materials of the electrodes 3, 4 and the wirings 5, 7 are Ti, Ta which is a refractory metal having a small work function, or their alloys, so that they make ohmic contact with the photoelectric conversion film 2 and at the same time,
The adhesion between the photoelectric conversion film 2 and the insulating substrate 1 is improved. As the insulating substrate 1, a highly heat resistant substrate such as a ceramic substrate, an alumina substrate or a Pyrex glass substrate is used. As the organic insulating layer 6, it is preferable to use a heat resistant resin such as a polyimide resin or a polyamideimide resin.

FIG. 3 is a diagram showing a basic circuit configuration when the contact type one-dimensional image device produced according to the present invention is actually used. The resistors R1, R2 ... Shown are the common electrode 3 and the individual electrodes 4, 4.
It is the element resistance of each part of the photoelectric conversion film 2, that is, the picture element (light receiving element array) 10 between the space. Reference numeral 11 is a bias DC power supply for applying to the common electrode 3, and 12 is a load resistance for reading a signal current as a voltage, which is output to the signal output terminal 13.

Reference numeral 14 is a changeover switch, and each common electrode 3 is connected to the bias DC power supply 11 or the ground side by switching. 15 is a switch for connecting each individual electrode 4 to the load resistance 12,
The switches 14 and 15 are switching elements composed of, for example, C-MOS transistors, and the gates in the elements connected to the shift register sequentially perform switching operations.

With the above configuration, the photoelectric conversion film 2 forming each image element exhibits a resistance change according to the amount of received light, and this resistance change is output as a signal current by the bias DC power supply 11, so that the amount of light is output to the terminal 13. The corresponding voltage is output. Therefore, when each pixel is scanned by switching the switches 14 and 15, a resistance change is shown in accordance with the amount of light received by the light receiving element forming each pixel, and a signal for reading one-dimensional image information from the terminal 13 is output as a signal current. Is output.

With such a configuration, a blocking diode for preventing crosstalk is not required, and by adopting matrix wiring, it is possible to significantly reduce the number of switching elements, and it is easy to fabricate the elements and at the same time reduce the cost. Become.

The photoelectric conversion film produced in the examples of the present invention shows a very high photoconductivity, for example, a CdSe-based photoelectric conversion film is 695n.
Brightness / darkness ratio at the time of light irradiation of m, 30 lx is 10 ³ or more, and the photocurrent is 1
A signal of .mu.A or more is obtained, and it becomes possible to manufacture a contact type one-dimensional image device adopting a real-time reading method.
In addition, it has excellent optical response characteristics and shows a fast response of 5 msec or less at both rising (90%) and falling (90%),
It exhibits extremely favorable characteristics as a high-speed reading element.
Furthermore, since the light receiving element is completely sealed by the organic insulating resin film, the element characteristics due to environmental changes are extremely small.

Further, the photoelectric conversion film of the device manufactured by the present invention can be manufactured by screen printing a photoconductor paste, and the organic insulating layer can also be formed by a coating process, so that it is excellent in mass productivity. There is.

Hereinafter, the steps of manufacturing an element using the CdSe photoelectric conversion film will be described in detail.

A Corning # 7059 glass substrate is used as the insulating substrate 1, a photoconductive paste is applied onto the substrate 1 by a screen printing method, dried at 100 ° C for 1 hour with hot air, and then at 300 ° C in a N ₂ atmosphere. Heat treatment was performed for 15 minutes, and subsequently for 500 minutes at 500 ° C. to form a photoelectric conversion film having a thickness of about 4 μm. The photoconductive paste has an average particle size of about 2 which has been previously heat treated for activation.
μm CdSe crystal powder (Cu: 0.4 mol% dope, 800 ° C. powder in N ₂ ) CdCl ₂ 3 mol%, low melting point glass frit (Tg: 38
2% by weight based on the total amount (5 ° C.) and an appropriate amount of oil (containing 1.5% by weight of ethyl cellulose) for viscosity adjustment were added and mixed in a ball mill for about 50 hours.

The common electrode 3 is formed on the photoelectric conversion film 2 thus manufactured.
The counter electrode including the individual electrodes 4 was formed by the lift-off method, and the lower layer wiring 5 was formed. In this embodiment, about 5000Å of Ti is deposited as electrodes and wiring, and the electrode interval is 50 μm,
A light receiving element array consisting of 1728 pixels having an electrode length of 70 μm was formed. A polyimide resin layer 6 having a film thickness after curing of about 5 μm was formed on the entire surface by spin coating as an interlayer insulating film and an element protective film. To form a through hole for forming a matrix wiring, first, a polyimide resin was patterned in a half-cure state by using a normal photolithography technique, Ni-Cu was adhered as an upper wiring material, and then the polyimide resin film was cured. The upper wiring pattern was formed by using a normal photography technique to form a matrix wiring having 32 elements as one block.

Since the interlayer insulating layer 6 of the matrix wiring portion was formed simultaneously on the light receiving element after the lift-off process, it was not affected by the upper wiring formation process and no deterioration of the characteristics of the photoelectric conversion film was observed.

The device manufactured by the above method was able to read an average signal current of about 15 μA with respect to incident light with a bias voltage of 12 V and 30 lx, and the variation in output characteristics between the pixels was as good as ± 15%. In addition, the light response speed rises (90%) 3.0m
It showed excellent response characteristics with a rise of sec (90%) of 0.5 msec, and was able to fabricate a high-speed contact type one-dimensional image element that can be read by a real-time reading method. Furthermore, when this device was subjected to a reliability test in a high temperature and high humidity environment of 65 ° C and 95% RH, the characteristic variation was within 5% even after 200 hours, and a good result was obtained. The polyimide resin formed on the photoelectric conversion film The layers are
It was found that the device sufficiently functions as a sealing film for improving the reliability of the device.

<Effects of the Invention> As described above, according to the present invention, since the light receiving element array is simultaneously sealed in the matrix wiring forming step, the number of steps can be simplified and the mass productivity is excellent. Therefore, according to the present invention, it is possible to manufacture a highly reliable device at a low cost with a high yield of device manufacturing.

[Brief description of drawings]

FIG. 1 is a partial plan view of a contact-type one-dimensional image device manufactured according to an embodiment of the present invention, and FIG. 2 is FIG.
FIG. 3 is a view showing a cross section of a part, and FIG. 3 is a view showing a basic circuit configuration when the contact type one-dimensional image device manufactured according to the present invention is actually used. 1 ... Insulating substrate, 2 ... Photoelectric conversion film, 3 ... Common electrode, 4 ... Individual electrode, 5 ... Lower layer wiring, 6 ... Organic insulating film as interlayer insulating film and element protective film, 7 ... … Top wiring.

Claims (1)

[Claims] 1. A II-VI group compound semiconductor containing at least Cd, one or more kinds of halogenated Cd and a low-melting-point glass frit dispersed in an organic binder, and the paste is applied to a substrate, which is then subjected to a heat treatment step. In the contact type one-dimensional image element in which the light receiving element composed of the photoelectric conversion thin film and the matrix wiring part are provided on the same substrate, the light receiving element forming film is provided in a strip shape so as to cover both sides of the film. A step of forming a common electrode and a stripe-shaped individual electrode, and continuously forming a lower layer wiring with the individual electrode; and an interlayer insulating film and an element protective film on the light receiving element section and the lower wiring section, and an insulating property. And a step of forming an insulating film composed of a polymer film, and a step of forming a matrix wiring in which the upper wiring portion is divided into blocks on the insulating film. Method for producing a contact type one-dimensional image element that.