Semiconductor device manufacturing: process – Coating of substrate containing semiconductor region or of...
Reexamination Certificate
1995-02-03
2001-09-25
Smith, Matthew (Department: 2825)
Semiconductor device manufacturing: process
Coating of substrate containing semiconductor region or of...
C438S761000, C438S763000, C118S718000, C118S7230VE, C118S7230FI, C118S7230EB, C204S298050, C204S298080
Reexamination Certificate
active
06294479
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a film forming method for continuously forming a desired film on a surface of a substrate selected from various kinds of materials such as macromolecular materials, metals, glass, ceramics, etc., and an apparatus therefor.
2. Description of the Related Art
In recent years, film forming using vacuum evaporation of a particular material onto the surface of a substrate has been widely adapted for forming a metal film as a printed wiring precursor onto a printed wiring substrate formed from a macromolecular material, forming a of a corrosion-resisting film onto a surface of a substrate formed from stainless steel or the like, and forming of a semiconductor film onto a liquid crystal display glass substrate, for example. Such vacuum evaporation film forming has an advantage in that the film forming speed is relatively high compared with film forming using sputtering or the like.
Vacuum evaporation film forming, however, has a problem in that mutual adhesion at the interface between the substrate surface and the film formed thereon is to weak that the film may be separated from the substrate when the substrate is processed after the film is formed. For example, where an aluminum film for printed wiring is formed on a surface of a printed wiring substrate formed of a polyimide film, a problem arises in that the aluminum film may be separated by exposure of the film to high or low temperature after the film is formed. In the case where a corrosion-resisting aluminum film is formed on a stainless steel substrate, for example, the aluminum film may be broken or separated when the stainless steel substrate is processed by bending, pressing or the like after the film is formed.
A method has been heretofore proposed to solve the aforementioned problems and in which vacuum evaporation of a particular material onto a surface of a substrate and ion radiation are used in combination to form an adhesive mixed layer of constituent atoms of the substrate material and constituent atoms of an evaporated material on a portion of the substrate surface to form an evaporation film of the same material and of a predetermined thickness on the mixed layer with good adhesion.
In forming the mixing layer to improve the adhesion, all the thickness of the resulting film is not necessary. That is, a film with an arbitrary thickness is formed by vacuum evaporation after the mixing layer is formed by ion radiation adjacent to the interface between the substrate and the film.
In such a film forming process using a combination of vacuum evaporation and ion radiation, continuous movement of a strip-like or plate-like substrate has been proposed for the purpose of film forming efficiency.
FIG. 5
shows an example of an apparatus for performing such continuous film forming, in which a vacuum vessel
9
capable of being kept in a predetermined vacuum by an exhaust device (not shown), is partitioned into two portions
91
and
92
. One portion
91
is used for a material evaporation source
93
and an ion source
94
for forming a mixed layer, and the other portion
92
is used for a material evaporation source
95
for forming an evaporation film of predetermined thickness on the mixed layer. A substrate
96
is passed from the one portion
91
to the other portion
92
so that the mixed layer is formed at the portion
91
and then the evaporation film of predetermined thickness is formed at the portion
92
.
The reason why the vacuum vessel
9
is partitioned into two film forming portions
91
an
92
is that if the film forming condition is suited to the moving speed of the substrate, it is necessary to reduce the speed of evaporation to satisfy the quantity of ion radiation in the mixed layer forming step. If the total film forming speed is increased, it is necessary to change the speed of evaporation between the mixed layer forming step and the evaporation film forming step.
Another method and apparatus have been proposed as described in Japanese Patent Unexamined Publication No. Sho-60-141869. In this proposed film forming method and apparatus, a first ion source, a first evaporation source, a second ion source and a second evaporation source (which may be combined with an ion plating means) are disposed in a vacuum vessel along the direction of substrate feed to carry out a pretreatment, such as cleaning, of the substrate surface using the first ion source, form an evaporation film for forming a mixed layer using the first evaporation source, form the mixed layer by ion radiation with the second ion source and form an evaporation film of a predetermined thickness on the mixed layer with the second evaporation source.
In the film forming method and apparatus described in each of FIG.
5
and Japanese Patent Unexamined Publication No. Sho-60-1414869, not only at least one ion source and one evaporation source are necessary for forming the mixed layer, but at least one evaporation source is also necessary for forming the evaporation film. Thus, a problem is present in that the number of evaporation sources is increased and film forming cost is increased.
In the method and apparatus described in Japanese Patent Unexamined Publication No. Sho-60-141869, the mixed layer is formed by performing ion injection with the second ion source after forming the evaporation film using the first evaporation source. Accordingly, ion energy due to the second ion source must be enlarged. Otherwise, great reduction of the substrate feeding speed may be considered, but production efficiency is compromised if the substrate feeding speed is reduced greatly.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above circumstances and has an object to provide a film forming method and a film forming apparatus in which a film with good adhesion characteristics can be continuously formed on a substrate easily, at low cost and with good productivity as compared with the conventional method and apparatus.
Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purpose of the invention, as embodied and broadly described herein, the present invention provides a film forming method characterized by forming a mixed layer of substrate material atoms and evaporation material atoms on a surface of an objective substrate by vacuum evaporation of a predetermined amount of material from an evaporation source to the surface of the substrate and radiation of ions from an ion source while the substrate is moved in a predetermined direction, and forming a film with a predetermined thickness the mixed layer, using the evaporation source, by vacuum evaporation while the substrate is continuously moved in a direction the same as or opposite to the predetermined direction after the mixed layer has been at least partially formed on a predetermined portion of the substrate surface by the first-mentioned step.
The present invention further provided a film forming method characterized in that ions are radiated from an ion source onto a surface of an objective substrate and, at the same time, a predetermined amount of material from an evaporation source is transferred by vacuum evaporation to the surface of the substrate while continuously moving the substrate, the ion radiation being applied to a substrate portion upstream in the direction of substrate movement, which is lower in evaporation speed than a center portion of a region reached by the evaporation material from the evaporation source, so that a mixed layer of substrate material atoms and evaporation material atoms is formed continuously on the surface of the substrate and then a vacuum evaporation film with a predetermined thi
Ebe Akinori
Nishiyama Satoshi
Ogata Kiyoshi
Suzuki Yasuo
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Keshavan Belur
Nissin Electric Co., LTD
Smith Matthew
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