JP2005163133A - Sputtering film deposition apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sputtering film deposition apparatus in which gases introduced into a chamber are less liable to be mixed with each other without complicating the apparatus constitution. <P>SOLUTION: In the apparatus constitution, a reactive gas is introduced into a cylindrical or concentric rotary type substrate holding means and a concentric shutter unit. The reactive gas is introduced at a position where the shutter forms a shuttering part at the film deposition time. In this way, sputtering particles can be deposited on a substrate in a state close to a metal mode without complicating the apparatus constitution, thus metal oxide having a stoichiometric value close to the theoretical one can be efficiently produced at a high thin film deposition rate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sputter deposition apparatus having a cylindrical or concentric rotating substrate holding mechanism, in which a sputtering gas and a reactive gas are spatially separated to stabilize a film deposition process and to deposit a thin film. The present invention relates to a sputtering film forming apparatus for raising the temperature.

  Conventionally, as disclosed in Patent Document 1, a countermeasure has been taken by providing a partition in the chamber so that a plurality of gases introduced into the chamber do not mix with each other. Alternatively, in the sputtering process zone, only sputtering gas is introduced and the film-forming particles are sputtered in the metal mode to deposit the metal particles on the substrate. In the oxidation process zone separated by the partition walls, oxidizing agents such as radicals are applied to the substrate. Has been addressed by oxidizing the metal particles by irradiating them, ie, making the sputter process zone and the oxidation process zone spatially completely independent.

Japanese Patent Laid-Open No. 7-18434

  In the conventional sputter film formation technique, the number of substrates that can be formed by one film formation is very limited, resulting in an increase in cost.

  However, in the case of a general application such as an optical thin film such as a dichroic mirror, cost is a top priority. Therefore, it has been required to improve throughput by using a large area target and forming a homogeneous film in a wider area. As a substrate holding method, various forms such as a carousel method and an in-line method are conceivable.

  However, generally the amount of film deposited on the target is not uniform. This is because it varies depending on various conditions such as the strength and shape of the target magnet, the plasma parameters of the film forming chamber, the partial pressure, flow rate, and type of the introduced gas.

Therefore, an attempt was made to eliminate the distribution of the thin film deposition rate as a whole by reducing the amount of deposition at the portion with the highest thin film deposition rate. As the method, there is a method of arranging and adjusting a film thickness correction plate or a metal guide bar. These have been effective in adjusting and uniforming the thin film deposition rate. However, since the uniformization is achieved by lowering the thin film deposition rate, the time required for one film formation becomes longer and the throughput is increased. A decline was inevitable. Therefore, in order to improve the throughput without increasing the size of the apparatus, it is necessary to improve the thin film deposition rate itself.

  One solution for this is to form a film in metal mode. In the conventional general reactive sputtering, the sputtering gas and the reactive gas are mixed and irradiated onto the target, so that sputtering with sputtered particles and oxidation of the metal surface with the reactive gas occur on the target metal surface. This is because the film is formed at the same time and the film is formed according to the equilibrium state between them, so that the film deposition rate is reduced by an order of magnitude compared to the case where the film is formed by irradiation with only the sputtering gas.

  On the other hand, in order to form a metal oxide by forming a film in metal mode, it is necessary to oxidize metal particles by some method. As one of the methods, only sputtering gas is present in the vicinity of the target space. A method of completely separating the sputtering process and the oxidation process by providing a partition in the chamber so that only reactive gas exists in the space and arranging an exhaust mechanism etc. in each partitioned space has been devised. . Alternatively, a method has been proposed in which a similar effect is obtained by irradiating a substrate with radicals in an oxidation process while having the same partition wall and exhaust mechanism.

  However, both of them require a partition for spatially separating the sputtering gas and the reactive gas, and a mechanism for exhausting each partitioned space, so that the apparatus configuration is likely to be complicated, Therefore, the problem is that the apparatus cost increases.

  In view of the above problems, an object of the present invention is to provide an apparatus configuration in which gases introduced into a chamber are not easily mixed with each other without complicating the apparatus configuration. That is, in a sputtering apparatus having a cylindrical or concentric rotating substrate holding mechanism, it has a shutter mechanism concentric with the holding mechanism, and its opening and closing portion are parallel to the rotation direction of the substrate holding mechanism. By rotating, the apparatus is configured to define the start / end of the film formation state. At the time of film formation, the target is rotated so that the opening is in front of the target, and only the sputtering gas is irradiated in the vicinity of the target. At the same time, in the vicinity of the shutter closing portion, the reactive gas is introduced between the rotary substrate holding mechanism and the shutter mechanism to irradiate the substrate with the reactive gas, and the metal particles irradiated on the opening and deposited on the substrate. React with.

  By adopting such a configuration, the metal particles irradiated at the opening can be immediately oxidized, so that a metal oxide thin film having a composition close to the stoichiometric value is obtained. Therefore, it becomes a thin film with very little absorption. In addition, since a partition wall mechanism for spatially dividing the interior of the chamber and an associated exhaust mechanism are not required, it is possible to obtain the maximum thin film deposition rate with the minimum required simple apparatus configuration, and the throughput is increased. Rise and lead to cost reduction. This makes it possible to produce high-quality products at a low cost.

  In order to achieve the above object, in the apparatus configuration of the present invention, a reactive gas is introduced between a cylindrical or concentric rotating substrate holding mechanism and a concentric shutter unit. The introduction position is a position where the shutter becomes a closed portion during film formation. This makes it possible to deposit sputtered particles on the substrate in a state close to the metal mode without complicating the apparatus configuration, so that the thin film deposition rate is high and the stoichiometrically close to the theoretical value. Can be produced efficiently.

  The target is irradiated with only the sputtering gas, and the reactive gas is disposed between the shutter and a rotating substrate holding mechanism such as a carousel to irradiate the substrate. Therefore, it is possible to spatially separate the sputtering gas and the reactive gas without substantially changing the configuration of the conventional reactive sputtering apparatus. By forming a film under such conditions, metal particles adhere to the substrate in metal mode during sputtering. Accordingly, the deposition rate on the substrate is increased.

  Further, when the substrate is rotated and immediately irradiated with the reactive gas, the metal particles on the substrate are sufficiently oxidized, and a metal oxide transparent dielectric thin film with little optical loss can be obtained.

  From the above, reactive gas is introduced between a cylindrical or concentric substrate holder that can obtain a large amount of optical thin films such as dichroic filters with excellent optical characteristics at low cost, and a concentric shutter unit. To do. The introduction position is a position that becomes a closed portion during film formation. This makes it possible to deposit sputtered particles on the substrate in a state close to the metal mode without complicating the apparatus configuration, so that the thin film deposition rate is high and the metal oxide is close to the stoichiometric theoretical value. A thin film can be produced efficiently.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 shows a film forming apparatus used for a method of forming an optical thin film according to an embodiment, which includes a decompression chamber 1 evacuated by a vacuum pump (not shown), a cylindrical or concentric substrate holder 2 and a substrate holder 2 opposite thereto. A target 3, an RF power source 4 and a DC power source 5 for applying a high frequency voltage and a direct current voltage to the target 3, an argon introduction line 6 for introducing an argon gas as a sputtering gas into the decompression chamber 1, and a reactive gas. It has an oxygen introduction line 7 for introducing a certain oxygen gas or a more active ozone gas, and the high frequency voltage of the RF power source 4 is applied to the target 3 through the matching network 4a, and the DC voltage of the DC power source 5 passes through the low-pass filter 5a. Then, it is applied to the target 3.

  Next, a process for forming an oxide thin film on the substrate W1 will be described.

First, the substrate W1 is held on the substrate holder 2, the decompression chamber 1 is decompressed to a predetermined vacuum degree, and then argon gas is introduced from the argon introduction line 6, oxygen gas or ozone gas is introduced from the oxygen introduction line 7, and the target 3 is applied with at least one of a high-frequency voltage of the RF power source 4 or a direct-current voltage of the DC power source 5 to generate plasma 1 by so-called magnetron sputtering discharge. The target 3 is sputtered mainly by positive ions of argon, and the substrate W1.
Is released towards. At that time, the particles are deposited on the substrate in a state of being partially oxidized by oxygen or ozone ejected from the inside of the carousel shutter, and most of the particles are metal particles.

  Next, the metal atoms deposited on the substrate surface are oxidized by oxidizing active species such as oxygen and ozone released from the oxygen introduction line 7 installed at the shutter closing portion by rotating the substrate holder. That is, the metal particles sputtered by the argon gas at the shutter opening 9 shown in FIG. 2 are immediately oxidized by the oxidizing active species irradiated in the shutter-like adjacent closing portion 10 and stoichiometrically become theoretical values. Near metal oxides are produced.

  Since the opening of the substrate holder rotates at a sufficient speed, the deposition of metal particles on the substrate and the oxidation by the oxidizing active species are immediately performed. That is, in the process of depositing metal particles on the substrate, the deposition rate on the substrate is extremely fast due to sputtering in the metal mode, and the oxidized active species introduced from the pipe disposed in the shutter are immediately oxidized. As a result, the metal particles deposited on the substrate can be sufficiently oxidized, and a metal oxide transparent dielectric thin film with very little optical loss can be obtained.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to these Examples at all.

  First, a 5 × 15 inch size target made of metal Ta is prepared. Next, a substrate holder having a decahedron carousel structure is prepared and rotated at a rotational speed of about 60 to 100 rpm. Prepare a shutter that is concentric with the center of rotation of the carousel. This is partly an opening and partly a closed part. When the shutter unit itself rotates in the carousel rotation direction or in the direction opposite to the rotation direction, particles adhere to the substrate during discharge. You can control the timing.

  Argon gas, which is a sputtering gas, is irradiated in the vicinity of the target, and oxygen gas, which is an oxidation active species, is disposed in a space formed between the shutter and the carousel. In addition, when a highly reactive substance such as titanium is used for the target, it may be stabilized as a metal element on the substrate before irradiating oxygen, so in such a case, ozone gas with higher oxidizing ability is used. It is desirable to use it.

  With such a configuration, it becomes possible to substantially separate the sputtering gas and the oxygen gas which is a reactive gas spatially. This is because the integrated shutter unit constitutes a substantially closed space. Argon gas and oxygen gas were introduced from the same pipe and discharged in oxide mode, and the deposition rate on the substrate was measured. The result was 0.12 nm / sec at the position of the substrate holder facing the center of the target. On the other hand, when the argon gas is irradiated to the target and the oxygen gas is irradiated to the substrate in the shutter as described above, the deposition rate on the substrate is 0.410 nm / sec, which is about 3.4 times the value. I was able to get it. Both optical thin films have an optical loss of 0.10% or less in terms of 100 nm, and have sufficient characteristics for general optical applications such as broadcasting equipment and dichroic filters.

  INDUSTRIAL APPLICABILITY The present invention can be applied to a sputter deposition apparatus having a cylindrical or concentric rotating substrate holding mechanism to obtain a large amount of an optical thin film such as a dichroic filter having excellent optical characteristics at a low cost. The effect that it is possible can be produced.

It is explanatory drawing explaining the film-forming apparatus used for the manufacturing method of the optical thin film by one Embodiment of this invention. It is a figure explaining the shutter unit and rotary substrate holding mechanism by one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Depressurization chamber 2 Substrate holder 3 Target 4 RF power supply 5 DC power supply 6 Ar introduction line 7 O2 introduction line 8 Shutter unit 9 Shutter opening 10 Shutter closing part

Claims (1)

In a sputter deposition apparatus using a sputtering method having a cylindrical or concentric rotating substrate holding mechanism,
It has a shutter unit concentric with the substrate holding mechanism, and a reactive gas can be introduced between the rotary substrate holding mechanism and the shutter unit, and a plurality of gases introduced into the chamber are mutually connected. A sputter deposition apparatus characterized in that it is difficult to mix.

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