JPS62105469A - Reading device and its manufacture - Google Patents

Abstract

PURPOSE:To improve a step-coverage extremely, reduce the contamination of a protection layer surface, obtain excellent photosensitivity, and improve the value of S/N, by forming a taper in a light-passing hole part of a photoconductor so as to become gradually thin toward a light source. CONSTITUTION:After a draw-out electrode 8 made of ITO as an individual electrode of closely adhered readout system is formed so as to be about 3,000Angstrom thick, a pattern for amorphous silicon etching is performed. In the etching process of a photoconductor, a taper is formed in the light-passing hole part 6a of a photoconductor 6, so as to become gradually thin toward a light source, by applying both etching liquid with high etching rate and an etching liquid with low etching rate. A light-passing hole 10 is formed by etching a common electrode 5, and a light-receiving part is formed to make up a photoelectric conversion element by etching of a transparent electrode 7 and a draw-out electrode 8. Whichever method may be adopted for forming a protection layer 9, defects for step-coverage can not be found, and the unevenness of the stuck- surface of the protection layer 9 can be extremely reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention aims at downsizing facsimile machines, for example, and uses a photoelectric conversion element array that corresponds substantially 1:1 in size to a document. The present invention relates to a reading device such as a contact type image sensor that is arranged in the form of a contact image sensor. Furthermore, it relates to its manufacturing method.

[Prior art and its problems]

Recently, the development of contact image sensors has become more active.
Various types of this device have been studied, including a type that detects the reflected light from the original through a condensing rod lens array, and a type that achieves excellent light transmittance and miniaturization without using this array.

FIG. 1 is a schematic diagram showing a close-contact reading system that does not use a focusing Rondo lens array, in which a light detection section 2, which has a substantially 1:1 dimensional correspondence with the original 1, is placed in close contact with the original 1. A light source such as a light emitting diode 3 projects light onto the original 1, and the light detecting section 2 receives the reflected light.

2 and 3 show a reading device corresponding to the photodetector 2, and FIG. 3 is a cross-sectional view taken along line X--X in FIG. 2.

That is, common electrodes 5a, 5b, . . . are formed on a substrate 4 made of a light-transmitting transparent material, such as glass, by vapor-depositing chromium, aluminum, or the like at intervals. A photoconductor 6 is formed on the common electrodes 5a, 5b. A transparent electrode 7 made of a light-transmissive transparent material such as tin oxide (ITO) is formed on the photoconductor 6-L by sputtering or vapor deposition. A transparent electrode 7 is formed individually for each photoelectric conversion element, and a lead electrode 8 is formed by vapor-depositing chromium, aluminum, etc. in correspondence with the electrode 7 individually. A protective layer 9 made of a light-transmitting transparent material, such as glass, is formed on the top. Light passing holes 10 are formed in the common electrodes 5a and 5b, the photoconductor 6, and the transparent electrode 7.

Further, a light emitting diode 1-3a as a light source is arranged behind the substrate 4, and an original 1 is arranged above the protective layer 9, and the light emitting diode 3a passes through the substrate 4 and the protective layer 9 and is projected onto the original 1. Shine. This reflected light passes through the transparent electrode 7 near the light im-hole 10 and is received by the photoconductor 6. In this way, photoelectric conversion elements are formed near each light passage hole 10, resulting in a reading device arranged in an array.

J- According to the above photodetecting section, it is formed by the steps shown in FIG. 4 [4A] to [4E]. That is, in [4A], the substrate 4
A common electrode 5, a photoconductor 6, a transparent electrode 7, and an extraction electrode 8 are sequentially formed thereon. Note that 11 is a resist film.

Next, in [4B], the photoconductor 6, for example, an amorphous silicon film, is plasma etched using CF4 gas.

In [4C], after removing the resist film, a photoresist pattern is formed again, the extraction electrode 8 and the common electrode 5 are etched, and the light receiving part and the light i1n hole (lO) are etched.
form. In [4D], step 1: further pattern forming with photoresist and etching the photoconductor 6 again;
The common electrode 5 is made to protrude toward the 1° side of the light passage hole. Finally, in [4E], the resist film 11 and a portion of the transparent electrode 7 on the individual electrode side are removed.

The photodetector thus obtained is as shown in FIG.

However, according to the photodetector, the protective layer 9 is 5i
When glass such as 02.5i-0-N is formed by sputtering or plasma CVD, the surface to which it is adhered has irregularities, resulting in poor step coverage and the photoconductor 6 being easily exposed. For this reason, the common electrode 5 is electrolytically corroded by humidity, moisture, etc., and the device characteristics are deteriorated.

Furthermore, along with the formation of the protective layer 9, the surface of the protective layer 9 is also formed with irregularities corresponding to the irregularities of the surface to which it is adhered.

Therefore, dirt and dust tend to accumulate on the four parts 9a of the protective layer 9, and the S/N ratio is lowered due to this noise component.

Furthermore, during the manufacturing process, in order to form a protruding portion of the common electrode 5 in the light passage hole 10, after etching the photoconductor 6, common electrode 5, and extraction electrode 8, the photoconductor was etched again. . Therefore, the light passage hole portion of the photoconductor 6 has four parts with a thickness of about 2 μm and a side of about 60 μm, which makes resist coating and mask alignment difficult, and there is a problem that exposure must be performed from the back side of the substrate.

Moreover, by CF4 plasma etching, the common electrode 5,
For example, there is a problem that chromium tends to corrode when a reverse bias is applied, and there is also a problem that the characteristics of the amorphous silicon photoconductor are deteriorated by plasma.

[Purpose of the invention]

Therefore, the purpose of the present invention is to solve all the problems caused by soft soil, and to improve the S/N ratio by suppressing the reduction of noise components.
The objective is to provide a high-performance reading device.

Another object of the present invention is to provide a method for manufacturing a reading device that aims to reduce manufacturing costs and improve manufacturing efficiency by simplifying the manufacturing process and improving manufacturing yield.

[Means to solve problems]

According to the present invention, a common electrode, a photoconductor, and an individual electrode are provided on a first plate surface of a substrate, a light source is arranged on a second plate side of the substrate, and a light passage hole is formed in the photoconductor. In addition to providing the light i
A plurality of 1ffl holes are formed dimensionally, and the light source emits light onto the object to be detected on the first plate side through the light passing hole, and the reflected light is received by a photoconductor near the 1ffl hole. There is provided a reading device in which a reading signal can be obtained by using a reading device, characterized in that a light imm through hole of the photoconductor is formed with a taper so as to taper toward the light source. .

Furthermore, according to the present invention, a plurality of photoelectric conversion elements are provided one-dimensionally on the first plate surface of the substrate, and a light source is arranged on the second plate surface side of the substrate to direct light to the photoelectric conversion elements. Forming a passage hole,
In the method for manufacturing a reading device in which light is emitted from the light source to the photodetector on the first plate surface side through the light passage hole, and the reflected light is received by a photoelectric conversion element, the following (A) to (F) are provided. ) A method for manufacturing a reading device is provided, characterized in that the light passing hole is tapered toward the light source by forming the light passage hole. That is, (A)...A common electrode is formed on the first plate surface of the substrate.

(B)...A photoconductor is formed on the common electrode.

(C)...Individual electrodes are formed on the photoconductor excluding the light jm passage hole.

(D) Etching the photoconductor.

1) Etching the common electrode to form a light passage hole.

(F)...A light receiving portion is formed on the individual electrode by etching.

〔Example〕

Hereinafter, the present invention will be explained in detail based on the electric circuit for a reader proposed by the present applicant in Japanese Patent Application Laid-Open No. 60-70870, taking the contact type reading system shown in FIG. 1 as an example.

FIG. 5 shows a manufacturing process according to the invention for manufacturing a reading device such as that shown in FIG. 2, and FIG. 6 shows a reading device according to the invention.

According to the manufacturing method of the present invention, in [5A] in FIG.
A chromium film was formed on 00, and then patterned by photolithography to form a common electrode 5.

Next, monosilane gas is decomposed by glow discharge to a thickness of about 1.
A 5 μm amorphous silicon film is formed to form a photoconductor 6.
And so.

Subsequently, an extraction electrode 8 made of TTO was formed as an individual electrode to a thickness of about 3,000 mm, and then a pattern T-for amorphous silicon etching was formed. [5B] and [5C] are photoconductor etching liquids, and [5B]
By using an etching solution with a fast etching rate in [5C] and an etching solution with a slow etching rate in [5C], a taper is formed in the light i11 hole 6a of the photoconductor 6 so as to taper toward the light source.

Next, in [5D], the common electrode 5 is etched using a photolithography method to form a light passage hole 10, and further, in [5E], the transparent electrode 7 and the extraction electrode 8 are etched to form a light receiving part, and a photoconductor is formed. It was used as a conversion element.

The thus obtained reading device of the present invention is shown in FIG. 6, and FIG. 7 is an enlarged view of the main part of FIG. 6, showing SiO□.

Plasma C using materials such as 5i-0-N, Si, N, etc.
No defects were observed in the stethoscope coverage even when the protective layer 9 was formed using either the VD method or the sputtering method.

In addition, since the unevenness of the surface to which the protective layer 9 is adhered has been significantly reduced,
Correspondingly, the four portions 9b appearing on the surface of the protective layer 9 were also significantly relaxed. Therefore, even when the present inventors operated the present device repeatedly, dirt and dust were unlikely to accumulate on the four parts 9b, and even if they did accumulate, they could be easily removed.

〔Effect of the invention〕

As described above, according to the present invention, the step coverage accompanying the formation of the protective layer has been significantly improved, and contamination on the surface of the protective layer has been reduced, resulting in excellent photosensitivity and improved S/N ratio. A reading device with improved reliability and long-term reliability was created.

Furthermore, since the manufacturing yield has been improved and the manufacturing process has been simplified, it has been possible to provide a method for manufacturing a reading device that achieves reduced manufacturing costs and high efficiency.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and any improvements, changes, etc. may be made without departing from the gist of the present invention.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the reading system of the reading device of the present invention;
Fig. 2 is a perspective view of a typical reading device, Fig. 3 is a sectional view of the conventional device taken along the cutting plane line X-X in Fig. 2, Fig. 4 is a process diagram showing the conventional manufacturing method, and Fig. 5 FIG. 6 is a sectional view of the apparatus of the present invention seen from the cutting plane line XX in FIG. 2, and FIG. 7 is a reading diagram of the present invention shown in FIG. 6. FIG. 2 is an enlarged cross-sectional view of the main part of the device. DESCRIPTION OF SYMBOLS 1... Original document 2... Light detection part 3.3a... Light emitting diode 6... Photoconductor 9... Protective layer 9a, 9b...
・Concavity

Claims (2)

[Claims] (1) A common electrode, a photoconductor, and individual electrodes are provided on the first plate surface of the substrate, a light source is arranged on the second plate side of the substrate, and a light passage hole is provided in the photoconductor. A plurality of light passing holes are formed one-dimensionally, and light is emitted from the light source to the object to be detected on the first plate side through the light passing hole, and the reflected light is reflected by a photoconductor near the light passing hole. A reading device configured to receive light and obtain a reading signal, characterized in that a light passing hole portion of the photoconductor is tapered so as to taper toward the light source. (2) A plurality of photoelectric conversion elements are provided one-dimensionally on the first plate surface of the substrate, and a light source is arranged on the second plate side of the substrate to form a light passage hole in the photoelectric conversion element. , a method for manufacturing a reading device in which light is emitted from the light source to the object to be detected on the first plate surface side through the light passage hole, and the reflected light is received by a photoelectric conversion element, the following (A) to ( F) A method for manufacturing a reading device is provided, comprising the step of forming a taper in the light passage hole toward the light source: (A)... a first plate of a substrate; Form a common electricity on the surface. (B)...A photoconductor is formed on the common electrode. (C)... Individual electrodes are formed on the photoconductor excluding the light passage holes. (D) Etching the photoconductor. (E) Etching the common electrode to form a light passage hole. (F)...A light receiving portion is formed on the individual electrode by etching.