Chemistry: electrical and wave energy – Processes and products – Coating – forming or etching by sputtering
Reexamination Certificate
1998-02-18
2001-03-13
Nguyen, Nam (Department: 1753)
Chemistry: electrical and wave energy
Processes and products
Coating, forming or etching by sputtering
C204S298070, C204S298110
Reexamination Certificate
active
06200431
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a reactive sputtering apparatus, and more particularly belongs to the technical field of thin-film forming processes suited for forming electrodes or protective films for semiconductor elements, electrodes or protective films for liquid-crystal devices, protective films for photomagnetic recording media, reflection preventive films (including anti-reflection coating films) or reflection enhancing films for optical articles, or the like by the use of such an apparatus.
2. Related Background Art
Conventional reactive sputtering is a process in which a mixed gas of a sputter gas and a reactive gas is introduced into a reaction chamber and a metallic target is sputtered to form a metallic compound thin film by a chemical reaction of constituent atoms of the target with the reactive gas. In this instance, the reactive gas may react with the metallic target on the target surface to form a metallic compound on the target surface. Usually, since the sputtering yield with respect to a metallic compound is about 10% of that with respect to the metal, the deposition rate may lower in the reactive sputtering. If the reactive gas is fed at a lower flow rate in order to improve the yield, the metallic compound thin film may be formed as having a higher content of metallic atoms, and can not possibly be a thin film that satisfies the stoichiometric ratio, resulting in poor thin-film characteristics in respect of optical characteristics (such as refractive index and transmittance) and so forth.
Accordingly, some attempts to solve such technical problems are proposed.
FIG. 8
is a schematic view of a reactive sputtering apparatus disclosed in Japanese Patent Application Laid-Open No. 62-56570. Reference numeral
1
denotes a target;
2
, a substrate;
3
, a supply pipe for argon (Ar) serving as a sputter gas;
4
, a supply pipe for oxygen (O
2
) serving as a reactive gas;
9
, a reaction chamber;
12
, a target holder; and
7
, a substrate holder.
The above publication states that the use of the apparatus shown in
FIG. 8
makes the rate of sputtering larger and brings about an improvement in the characteristics of the oxides, since the sputter gas and the reactive gas are separately introduced, and since the sputtering takes place preferentially in the vicinity of the target and the oxidation reaction takes place preferentially in the vicinity of the substrate.
In reality, however, the sputter gas and the reactive gas mix at a zone between the target and the substrate to form a mixed plasma of both. Especially when a thin film is formed on a large-area substrate, the discharging region between the substrate and the target is so large that the sputter gas and the reactive gas can be separately present with difficulty. Thus, the film quality and the rate of sputtering can not be so much improved as expected.
Meanwhile,
FIG. 9
is a schematic view of a reactive sputtering apparatus disclosed in Japanese Patent Application Laid-Open No. 6-41733. Reference numeral
1
denotes a target;
2
, a substrate;
3
, a supply pipe for argon (Ar) serving as a sputter gas;
4
, a supply pipe for oxygen (O
2
) serving as a reactive gas;
7
, a substrate holder;
8
, a power source;
9
, a reaction chamber;
12
, a target holder;
13
, a differential pressure plate;
14
, a high frequency power source;
15
, a coil;
16
, a magnet;
17
, a pipe for circulating a refrigerant; and
18
, an exhaust pump.
In this apparatus, an exhaust vent communicating with a vacuum pump is provided at an upper part of the reaction chamber
9
, and the differential pressure plate
13
is utilized to produce a difference in pressure between the reaction chamber upper part and the reaction chamber lower part so that the sputter gas and the reactive gas can be separated.
Japanese Patent Application Laid-Open No. 7-335553 discloses a reactive sputtering apparatus proposed in order to achieve an object different from the object of the above apparatuses. This apparatus is provided with a collimator between the target and the substrate in order to fill up contact holes of semiconductor devices.
The specification and drawings of U.S. Pat. No. 5,415,753 and a publication “THE SECOND INTERNATIONAL SYMPOSIUM ON SPUTTERING & PLASMA PROCESSES, 1993, pp. 269-274” also disclose a reactive sputtering apparatus provided with a perforated plate between a target and a substrate and so constructed that a sputter gas and a reactive gas are separately fed.
In the apparatus shown in
FIG. 9
, however, an opening
13
a
of the differential pressure plate
13
is larger in size than the substrate
2
, so that, in reality, the sputter gas will undesirably pass through the opening
13
a
of the differential pressure plate
13
to flow to the substrate
2
side. Hence, also in such an apparatus, the rate of sputtering and the film quality can not be so much improved as expected.
The apparatus disclosed in U.S. Pat. No. 5,415,753 has also no sufficient countermeasure for gas exhaustion, and the rate of sputtering and the film quality can not be so much improved as expected.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a reactive sputtering apparatus, and a thin film forming process, that can form a thin film having in-plane uniform thickness and optical and electrical characteristics.
Another object of the present invention is to provide a reactive sputtering apparatus, and a thin film forming process, that can form a uniform and large-area thin film at a high deposition rate.
The present invention provides a reactive sputtering apparatus comprising a substrate holding means for holding a substrate, a target holding means for holding a target, a sputter gas supplying means for supplying into a reaction chamber a sputter gas for sputtering the target, a reactive gas supplying means for supplying a reactive gas, and a power supplying means for supplying a power for causing a discharge to take place between the target and the substrate, wherein;
a partition member having a plurality of openings is provided between the target and the substrate, a first space being formed between the target and the partition member, and a second space being formed between the substrate and the partition member;
a sputter gas supply port for supplying the sputter gas to the first space and an exhaust passage for exhausting at least part of the sputter gas from the first space without passing through the plurality of openings are provided in the first space; and
a reactive gas supply port for supplying the reactive gas to the second space and an exhaust passage for exhausting at least part of the reactive gas from the second space without passing through the plurality of openings are provided in the second space.
The present invention also provides a thin film forming process for forming a thin-film using a reactive sputtering apparatus comprising a substrate holding means for holding a substrate, a target holding means for holding a target, a sputter gas supplying means for supplying into a reaction chamber a sputter gas for sputtering the target, a reactive gas supplying means for supplying a reactive gas, and a power supplying means for supplying a power for generating a discharge between the target and the substrate, the process comprising the steps of;
disposing the substrate and the target such that a partition member having a plurality of openings is interposed therebetween;
supplying the sputter gas to a first space between the target and the partition member and exhausting at least part of the sputter gas from the first space without passing through the plurality of openings;
supplying the reactive gas to a second space between the substrate and the partition member and exhausting at least part of the reactive gas from the second space without passing through the plurality of openings; and
generating a discharge between the target and the substrate, thereby forming on the substrate a thin film containing the constituent atoms of the target and the constituent atom
Canon Kabushiki Kaisha
Cantelmo Gregg
Fitzpatrick ,Cella, Harper & Scinto
Nguyen Nam
LandOfFree
Reactive sputtering apparatus and process for forming thin... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reactive sputtering apparatus and process for forming thin..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reactive sputtering apparatus and process for forming thin... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2546117