JPH0461070B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for surface treatment of an aluminum substrate for forming a thin film.

Conventional technology and problems to be solved by the invention Products manufactured by forming a thin film on the surface of an aluminum base material using the PVD method or CVD method include:
These include solar cells (thin film constituent material: amorphous Si), electrophotographic photoreceptors (thin film constituent material: Se or its alloy, amorphous Si, etc.), polygon mirrors (thin film constituent material: Al, SiO ₂ ), etc. Such a thin film must have uniform film quality and excellent adhesion to the substrate. However, in the manufacturing process of these products, various surface defects such as bulges, cracks, and pinholes may occur on the surface of the thin film during the formation of the thin film, which poses a major problem in terms of product quality. This point will be explained in more detail below regarding the electrophotographic photoreceptor. In copiers and laser beam printers that use electrophotographic technology, the surface of the aluminum base material is coated with Se or Se alloys such as Se-Te, Se-Te-As, and Se-As, semiconductors such as amorphous Si, and amorphous amorphous. Electrophotographic photoreceptors are manufactured by forming thin films made of materials such as metals, ZnO, CdS, and organic semiconductors using PVD or CVD methods to produce electrophotographic photoreceptors. There is a problem in that surface defects such as swelling, cracks, and pinholes occur on the surface of the photosensitive layer during formation of the photosensitive layer, which adversely affects electrophotographic images.

The causes of such thin film defects include gases released from the surface of the aluminum base material when the aluminum base material is heated to 200 to 300 degrees Celsius under vacuum during the process of depositing the deposition material in vacuum, and It is thought that contaminants such as processing oil that adhere to the surface of the base material during extrusion processing, rolling processing, pressing processing, and cutting processing have a large influence. In order to prevent the above defects from occurring in the thin film,
It is important to reduce gases released from the surface of the aluminum base material and to remove contaminants from the surface of the aluminum base material before forming a thin film. As a result of repeated experimental research on this point, the present inventors have come to believe that the state of the film on the surface of the aluminum base material before forming the thin film has a large effect.

As is well known, aluminum is a metal that is very easily oxidized, and when it comes into contact with oxygen, an oxide film is formed on the surface. Furthermore, when aluminum is placed in an environment containing moisture such as water or moisture, a hydrated oxide film is formed on its surface. The higher the temperature of the hydrated oxide production reaction, the more remarkable the growth of the hydrated oxide film.
In a high-temperature environment, a hydrated oxide film of boehmite (pseudo-boehmite) or vialite is formed on the aluminum surface. The quality of such a hydrated oxide film is much rougher and more porous than that of an aluminum oxide film formed in an environment where no moisture is present, and the pore morphology is also complicated. In addition, the film thickness is also thick.

By the way, a hydrated oxide film is formed on the surface of an aluminum material formed by ordinary extrusion processing due to contact with moisture-containing atmosphere (oxygen) during molding, and this hydrated oxide film is not exposed to high temperatures during molding. Because of this exposure, the formation reaction of a hydrated oxide film is promoted, resulting in a thick film. The quality of this hydrated oxide film is porous as described above, and since it is a thick film, a large amount of water is adsorbed to the film. Moreover, because the film lacks tightness, gases such as moisture, hydrocarbons, carbon dioxide, and carbon monoxide present in the atmosphere are adsorbed to the film even after molding. In addition, contaminants such as processing oil are also adsorbed to the film as described above. Moreover, since these hydrated oxide films are as described above, they are occluded in the film. As a result, it becomes difficult to remove these particles, and even if a vacuum is applied, they cannot be easily removed. Therefore, this seems to be the cause of defects in the thin film formed on the surface of the aluminum base material. In addition, in order to increase the mechanical strength of the aluminum material after forming, quenching treatment such as water cooling and air cooling after high temperature heating, and heat treatment are performed. As the film grows further, substances that have already been adsorbed and which cause defects on the surface of the thin film become incorporated into the film.

Moreover, rolling oil, which is a contaminant, is attached to the surface of an aluminum base material formed by rolling, and a porous hydrated oxide film is formed during rolling and annealing. Furthermore, processing oil, which is a contaminant, is also attached to the aluminum base material formed by press working, and a hydrated oxide film is formed.

Furthermore, when finishing an aluminum base material formed by extrusion, rolling, pressing, etc. in a manner that exposes a new surface, such as cutting or grinding in the atmosphere, the cut surface and A porous hydrated oxide film is generated on the ground surface by contact with the moisture-containing atmosphere (oxygen), and this hydrated oxide film is damaged by the heat generated during cutting or grinding. , the formation reaction of a hydrated oxide film is promoted, resulting in a thick film.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a method for surface treatment of an aluminum base material for forming a thin film, which can form a suitable thin film free of the above-mentioned surface defects.

Means for Solving the Problems The method of surface treatment of an aluminum base material for forming a thin film according to the present invention involves processing the surface of an aluminum base material by laser processing, electronic Beam processing, ion beam processing, reactive gas etching method, plasma etching method, reactive ion etching method, reactive ion beam etching method, ion beam etching method, and reactive laser beam etching method. It is characterized by applying processing to expose a new surface, and forming an oxide film on the new exposed surface at the same time as processing.

In the above, typical examples of aluminum base materials include base materials that support the photosensitive layer of electrophotographic photoreceptors, but other materials include base materials for solar cells, polygon mirrors, semiconductor devices, and the like. these are,
It is formed by extrusion molding, rolling, press molding, cutting, etc.

The above processing is performed on the surface of the aluminum base material on which the thin film is to be formed.

In the above, the following three methods can be cited as methods for processing in an oxygen-containing gas atmosphere that does not come into contact with the moisture-containing atmosphere.

Part 1 is oxygen 0.5-30vol%, especially 1-10vol%
%, and the remainder is an inert gas or a gas inert to aluminum. Argon and helium are common inert gases. Further, nitrogen gas is generally used as a gas inert to aluminum.

The second method is a method of processing in an inert gas atmosphere or a nitrogen gas atmosphere. Commercially available inert gases and nitrogen gases or industrially obtained inert gases and nitrogen gases contain trace amounts of oxygen.

The third method is processing in a vacuum atmosphere. Even a vacuum atmosphere contains trace amounts of oxygen.

In any of the three methods described above, the surface of the aluminum base material is prevented from coming into contact with the atmosphere containing moisture, so that no hydrated oxide film is formed on the surface. In these methods, a thin honey oxide film is formed on the active aluminum surface by heat energy during processing. In the first method, the thickness of the oxide film is about 20 to 60 Å, and in the second method, the thickness of the oxide film is about 20 to 60 Å.
With the method described above, the film thickness becomes thinner than this. Note that in the third method, it is difficult to control the dew point, so the first method
and the second method is preferred.

Then, the surface of the aluminum base material that has been surface-treated by the method of this invention is coated with the PVD method or
A thin film is formed by a conventional method such as CVD method. The material that makes up the thin film is Se in electrophotographic photoreceptors.
or Se such as Se−Te, Se−Te−As, Se−As, etc.
Alloys, semiconductors such as amorphous Si, amorphous metals, ZnO, CdS, organic semiconductors, etc.
For solar cells, it is amorphous Si, and for polygon mirrors, it is Al, SiO ₂ , etc.

Function The method for surface treatment of a thin film-forming aluminum substrate according to the present invention includes laser processing, electron beam processing, ion beam processing, reactive gas etching, A new surface is exposed using one of the following methods: plasma etching, reactive ion etching, reactive ion beam etching, ion beam etching, and reactive laser beam etching. Since an oxide film is formed on the newly exposed surface at the same time as processing, problematic hydrated oxides are not generated on the surface of the aluminum material, and instead a honeyed oxide film is formed. Moreover, since a honey oxide film can be formed on the newly exposed surface of the aluminum base material at the same time as the processing, the number of man-hours can be reduced. Furthermore, an oxide film can also be formed on the outer circumferential surface of the cylindrical base material, the surface of the plate-like base material, and the like.

Example Next, embodiments of the invention will be described.

After casting a JIS A3003 alloy billet, it was extruded into a pipe shape with an outer diameter of 90 mm and a wall thickness of 8 mm. The obtained extruded product was subjected to drawing processing to obtain a drum-shaped aluminum base material. This drum-shaped base material was ground in a mixed gas atmosphere consisting of 20 vol% oxygen and the balance argon, with an outer diameter of 80 mm and a wall thickness of 5 mm.
The length was 300mm.

A honey oxide film with a thickness of approximately 40 Å was formed on the surface of this drum-shaped substrate.

Next, on the surface of the drum-shaped aluminum base material,
Se alloy was vacuum deposited to form a thin film, ie, a photosensitive layer. When the surface of the photosensitive layer of the obtained electrophotographic photoreceptor was observed using an optical microscope and SEM, it was found that
No surface defects such as swelling, cracks, or pinholes were observed, and it was confirmed that a flat and extremely good photosensitive layer was formed.

Effects of the Invention According to the method for surface treatment of a thin film-forming aluminum base material according to the present invention, as described above, problematic hydrated oxides are not generated on the surface of the aluminum base material, and a honey oxide film is formed instead. compared to a hydrated oxide film, it is more effective at adsorbing gases and pollutants.
There is very little occlusion, and even if adsorption or occlusion occurs, it can be easily removed by degassing. Therefore, the amount of contaminants deposited on the surface of the treated aluminum substrate is reduced and, moreover, the amount of gas released onto the surface during vacuum deposition is much lower. It is possible to prevent various surface defects such as swelling, cracks, and pinholes from occurring in thin films, and it is possible to omit or reduce the conventional troublesome work to prevent surface defects from occurring. . In addition, since a honey oxide film is formed on the surface of the aluminum base material, even if it comes into contact with the atmosphere in the subsequent process, it prevents the adsorption of substances that cause the above defects on the surface of the thin film, and also prevents hydration oxidation. Formation of a film can be suppressed. Moreover, since a rich oxide film can be formed on the newly exposed surface of the aluminum base material at the same time as the surface processing, the number of man-hours can be reduced. In addition, since an oxide film can be formed on any part of various substrates, it can be easily applied to the outer peripheral surface of drum-shaped aluminum substrates used in electrophotographic photoreceptors and the surface of plate-shaped aluminum substrates. can be processed. Furthermore, such as rolled products and press-formed products,
When vacuum-lowering substances such as rolling oil and processing oil are attached to the surface, a honey oxide film is formed on the newly exposed surface of the aluminum base material at the same time as removing the vacuum-lowering substances. is possible,
It is possible to reduce the number of man-hours.

Claims (1)

[Claims] 1. Laser processing, electron beam processing, ion beam processing, reactive gas etching method, plasma etching method, reactive ion etching method is applied to the surface of the aluminum base material in an oxygen-containing gas atmosphere that does not come into contact with the moisture-containing atmosphere. Processing is performed to expose a new surface using one of the following methods: method, reactive ion beam etching, ion beam etching, or reactive laser beam etching. A method for surface treatment of an aluminum substrate for forming a thin film, characterized by simultaneously forming an oxide film.