JPS58111366A - Long thin film reading element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel image reading device for use in facsimile machines and printers that read fine images and perform information processing.

More specifically, the present invention relates to the structure of the base electrode of a long thin film element with a sandwich structure in which a uniform thin film of amorphous silicon is used as a photoconductor and electrodes are sandwiched on both sides of the photoconductor.

Conventionally, reading devices used in facsimiles, printers, etc. are COD, 7-otodiode P array, etc.
Semiconductor image sensors such as OS photodiode nine arrays have been widely used.

These image sensors usually use a reduction optical system, so a lens, etc. is required), which increases the optical path length, which poses a big problem when trying to make the device smaller. .

In response to this, the present applicant proposed in Japanese Patent Application No. 561/1987 a sandwich-type elongated reading/receiving element in which electrodes are sandwiched on both sides of amorphous silicon.

As shown in FIG. 1, this reading element is constructed by disposing base metal electrodes 5 on an insulating base 1 [8 so as to correspond to pins F], and using a photoconductor such as amorphous silicon to cover the base metal electrodes. An upper common transparent electrode 7 is provided on the thin plate-like layer 6, and this light-receiving element is as shown in FIG. 2 when viewed from the light incident surface.

In FIG. 2, 5-1 to 5-5 are underlying metal electrodes, 6 is a photoconductive layer, and 7 is an upper common transparent electrode.

A single type image sensor using such an amorphous semiconductor usually has base electrodes Aj, Or, A on the substrate 8.
u etc. using photolithography etc. to several 100 to several 10
Nozo turning with thickness of 0OA, +Il) upper KM arrival,
Pu2 Sma CV D, J/' 7 fi method 11
K) It is made by depositing an amorphous semiconductor as a film, but as shown in FIG. Therefore, when a voltage is applied between the upper and lower electrodes consisting of the lower metal electrode 5 and the upper common transparent electrode 7, dielectric breakdown (discharge) occurs in this part, destroying the element in this part and causing defects. It was easy for people to end up losing billions. Further, there was also a drawback that the amorphous semiconductor 6 in contact with the above portion was crystallized. In order to prevent these problems, a method has been considered in which the thickness of the base electrode 5 is made thinner to make the entire step part smaller. The drawback is that electrode defects are likely to occur.

The present invention has been made in consideration of the above disadvantages, and the purpose of the present invention is to eliminate the step difference in the base metal electrode in order to reduce defects in the amorphous semiconductor film caused by the step portion of the base metal electrode. It's about relaxing.

Specifically, the step at the end of the base electrode is made into a step-like shape of at least two steps, and each step is about half the size of the conventional step. To process the step, in the conventional process of photolithography and etching after electrode creation, the parts that require edge processing are removed, so during processing, the edge portion of the first step is etched 4 times, further reducing the step. be able to. Therefore, it is possible to prevent the amorphous semiconductor from becoming thin or the film quality from deteriorating in this portion, and it is possible to prevent the occurrence of defects. Sara K
By repeating this process and increasing the number of steps to two or more, you can create a smooth step shape.

A method for creating the structure of the underlying metal electrode as shown in FIG. 4 in a single-type image sensor using an amorphous semiconductor is shown in FIG.

(a) A base metal electrode 5 is formed on a substrate 8 using a known method, for example, by using a sintering method.

(b) A resist film 9 is provided on the surface of the other base metal by photolithography, leaving the step portion to be provided on the electrode 5.

(c) Etching the base metal electrode while adjusting the etching time according to the thickness of the step part to create a second step. At this time, since etching progresses in all directions, the edge portions of the first and second steps are formed gently, and the steps are relaxed as a whole, making it possible to create a round base electrode pattern as shown in FIG. 5(c).

When creating a step difference of three or more steps, the above steps (rotation) to (c) may be repeated as many times as necessary.

Next, as the amorphous semiconductor, im or pg 7 assilicon (a-8i) is used, Or is used as the base electrode, and ITO (indium tinoxide) is used as the upper transparent electrode.
An example will be shown in which the shape of the base electrode is improved in an air image sensor using e). In the sensor structure 10JC shown in FIG. 6, the thickness of the base metal electrode 50r is set to 2000 mm, and the processed portion is made of ITO as shown in FIG. 6(b).
All peripheral edges of the part of the sensor (large frame part) covered by (the shaded part).

The shape of the step is 10mm from the end as shown in Figure 7.
The range is in μmmt, and the Or etching time for processing is half of the etching time for normal J-turn creation, and the first step step difference is about 1000 steps. The broken line portion in FIG. 7 is the portion to be removed by etching. As a result, the step φI at the end of the base electrode is vertically relaxed, and it is possible to avoid the occurrence of various defects at the step portion that would otherwise occur with a conventional electrode pattern, thereby improving the yield of devices. .

In the embodiments of the present invention, an example in which a step is provided at the end of the base metal electrode has been described, but even if this portion is etched and rounded, the problem will still occur. As shown in Fig. 3, if the stepped portion 8 is angular, abnormal discharge is likely to occur and may cause element destruction, but even if this portion is rounded (r), this phenomenon can be prevented. I can do it.

As described above, the present invention provides the following advantages in the production of a plurality of metal electrodes:
To carefully create an obtuse angle or step shape at the end.
), it is possible to improve the fairness of the reading device.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a reading element according to the present invention, FIG. 2 is a view of the reading element of FIG. 1 viewed from the common transparent electrode side, and FIG. (This is a schematic diagram showing the shape)
. FIG. 4 is a schematic diagram of the base metal electrode of the present invention, and FIGS. Figure 6(a) shows a-8 after forming the base metal electrode of the present invention.
FIG. 7 is a schematic diagram of a light-receiving element provided with an i layer and a common transparent electrode layer, FIG. FIG. 3 is a diagram showing an example of a metal electrode. 5: lower metal electrode, 6: amorphous semiconductor, 7: upper transparent electrode, 8: step portion, 9 resist film. 1 Figure 13 Figure 5 m (a) 51 Continued from page 1 0 Inventor Mario Fuse 2274 Hongo, Ebina City Inside the Ebina Factory of Fuji Xerox Co., Ltd.

Claims (1)

[Claims] t A plurality of metal electrodes provided on an insulating substrate and divided into bits, a flat amorphous silicon layer formed on the plurality of metal electrodes, and a wrinkled amorphous silicon layer on the plurality of metal electrodes. In a long thin film reader consisting of nine transparent electrodes formed in a flat plate at a position facing the plurality of divided metal electrodes, a step is provided at the end of the plurality of divided metal electrodes. Features a long thin film reader. 2. The long thin film reading device according to claim 1, wherein the ends of the plurality of metal electrodes are rounded.