JP2009091603A - Apparatus for forming optical thin film and control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for forming an optical thin film, which can inhibit particles from being produced when forming the optical thin film, and to provide a method for controlling the apparatus. <P>SOLUTION: This film-forming apparatus includes: a vacuum chamber; a rotating drum which is provided in the inner peripheral surface of the vacuum chamber and can hold a substrate on its peripheral surface; and film-forming regions for sputtering metallic targets which are divided by a deposition shield plate, and an oxidation region for oxidizing a sputtered metallic thin film, which are provided in the peripheral direction of the rotating drum; and passes the substrate through each of the regions to form an optical thin film on the substrate, wherein the deposition shield plate has a temperature control means thereon. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a film forming apparatus for forming an optical thin film on a substrate by repeatedly sputtering a metal target and oxidizing the sputtered metal thin film, and a control method thereof.

Conventionally, a method for forming a metal oxide film by forming a metal thin film on a substrate held on a rotating drum and oxidizing it with oxygen plasma to form an oxide film is a high-quality optical method. It has been put to practical use as a method for forming a thin film (for example, Patent Document 1).
This optical thin film is used as an optical filter, and recently, the demand for high performance and multi-functionality has been increasing, and thus the demand for film properties has become severe. Among them, contamination and defects in the film caused by particles, pinholes, and the like are a major problem, and are the main causes of lowering yield in production.
By the way, in the case of the apparatus disclosed in Patent Document 1, normally, in order to prevent the sputtered material from being scattered, the film formation region is divided so as to prevent it from both sides of the target toward the rotating drum. A landing plate is erected.
However, oxygen that has passed between the deposition plate and the rotating drum reacts with the metal sputtered particles, becomes an easily detachable oxide (insulator), adheres to the deposition plate, and peels off due to charge-up. There was a problem that particles were generated.
In order to suppress this particle, a method of spraying Al on the deposition plate to reduce the exfoliation of the oxidized material can be considered, but it is sufficient suppression because the amount of generated particles increases with the plasma discharge time. The effect was not obtained.

JP 2005-206875 A

  Therefore, an object of the present invention is to provide an optical thin film deposition apparatus capable of suppressing particles when forming an optical thin film, and a control method for the apparatus.

In order to solve the above-mentioned problems, the present inventors have intensively studied and found the following solution.
That is, the optical thin film deposition apparatus according to the present invention comprises, on the inner peripheral surface of a vacuum chamber, a rotating drum capable of holding a base material on the peripheral surface, and the rotating drum. In the circumferential direction, a film formation region for sputtering a metal target divided by an adhesion-preventing plate and an oxidation region for oxidizing the sputtered metal thin film are provided, and the substrate is passed through each of the regions. An apparatus for forming an optical thin film on the substrate, wherein the deposition preventing plate is provided with a temperature control means.
Moreover, the present invention according to claim 2 is the optical thin film deposition apparatus according to claim 1, wherein the distance between the metal target and the substrate when facing each other is 120 mm to 300 mm. It is characterized by that.
The method for controlling an optical thin film deposition apparatus according to the present invention comprises, as described in claim 3, a rotating drum capable of holding a substrate on the inner peripheral surface of the vacuum chamber, In the circumferential direction of the rotating drum, a film formation region for sputtering a metal target divided by an adhesion preventing plate and an oxidation region for oxidizing the metal thin film pass through the base material in each region. A method of controlling an apparatus for forming an optical thin film on the substrate, wherein the temperature of the deposition preventing plate is adjusted to a range of 100 ° C. to 400 ° C. when the metal target is sputtered. It is characterized by.
Further, the present invention according to claim 4 is the method for controlling an optical thin film deposition apparatus according to claim 3, wherein the distance between the metal target and the substrate when facing each other is 120 mm to 300 mm. It was made to become.

  According to the present invention, the level of particles generated by film formation can be significantly reduced. As a result, it is possible to form a high-quality metal oxide film with few contamination and film defects, which leads to an improvement in production yield.

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic configuration of a film forming apparatus according to the present invention. A rotating drum 3 provided with a base material supporting means 2 is disposed at a substantially central portion of a vacuum chamber 1, and in order in the rotation direction, One film formation region 4, an oxidation region 5 and a second film formation region 6 are arranged.
The first film-forming region 4 for performing sputtering includes a sputter cathode 7 composed of two electrodes, a strip-shaped target 8 composed of Ta or the like disposed on the rotating drum 3 side of the sputter cathode 7, An AC power source 9 for applying an AC voltage to the sputtering cathode 7 and an Ar gas introduction system 10 for introducing Ar gas or the like are included. Similarly, the second film-forming region 6 for performing sputtering includes a sputtering cathode 11 composed of two electrodes, a target 12 composed of Si or the like, and an AC power source 13 for applying an AC voltage to the sputtering cathode 11. The second film formation region 4 includes a gas introduction system 14 for introducing Ar gas or the like. In addition, on both sides of the targets 8 and 12 in the respective film formation regions 4 and 6, deposition preventing plates 15 and 16 are erected toward the rotary drum 2 side. The oxidation region 5 includes an oxidation plasma source 17 and an Ar and O ₂ gas introduction system 18.

  Although not shown, the deposition preventing plates 15 and 16 are provided with temperature adjusting means such as a sheath heater and a lamp heater. Thus, the temperature of the deposition preventing plates 15 and 16 is adjusted to 100 ° C. to 400 ° C. at least in the film formation process by sputtering.

With the above apparatus, the base material 19 is fixed to the base material support means 2 of the rotary drum 3, a metal film of about a monoatomic layer is formed by sputtering in the first film formation region 4, and the metal film is formed by the oxidation region 5. Further, in the second film formation region 6, a metal film of about a monoatomic layer is formed on the second film formation region 6, and the metal film is oxidized by the oxidation region 5. Laminate to obtain an optical thin film.
In the present invention, when the metal film having a monoatomic layer is formed by sputtering, the temperature of the deposition preventing plates 15 and 16 is adjusted to a range of 100 ° C to 400 ° C. Thus, when the plasma is generated, the temperature of the deposition preventive plates 15 and 16 does not rapidly increase. Therefore, the oxidizing substance caused by the difference in thermal expansion coefficient between the deposition preventing plates 15 and 16 and the oxidizing substance attached thereto. Can be prevented.
Moreover, it is preferable that the mutual space | interval when the targets 8 and 12 and the base material 19 oppose is 120 mm-300 mm. Although the reason is not clear, it is known that when the temperature is controlled within this range, the generation of particles can be further suppressed when the temperature control of the deposition preventing plates 15 and 16 is performed.

  The metal film formation in the present invention is not particularly limited as long as it is by sputtering, and an ECR sputtering method, a magnetron sputtering method in which a magnet is placed on the back surface of the target to perform sputtering, or a DC power source may be used. A DC magnetron sputtering method, an RF power source using an RF magnetron sputtering method, or the like can be employed.

As the metal targets 8 and 12, those containing at least one element selected from Si, Ti, Ta, Nb, Al, Mg, Sb, Zr, Zn, Sn, and Ca can be used.
The dimensions of the targets 8 and 12 are not particularly limited. For example, the lateral direction can be 120 mm to 145 mm, and the longitudinal length can be 600 to 900 mm. Further, the shape includes a rectangular shape or an elliptical shape. In the case of an elliptical shape, the shorter one is defined as the shorter direction, and the longer one is defined as the longer direction.

Next, examples of the present invention will be described together with comparative examples.
Example 1
Using the film forming apparatus having the structure shown in FIG. 1, in the first film forming region 4, a rectangular SiO ₂ target 8 having a length of 145 mm in the short side direction and a length of 640 mm in the long side direction is placed inside the vacuum chamber. Sputtering was performed at 7.0 kW at 0.15 Pa, and a 500 ＳｉＯ SiO ₂ film was formed on a glass substrate 19 having a diameter of 15 mm and a thickness of 1 mm.
During the film formation period, the temperature of the deposition preventing plate 15 was adjusted to 280 ° C. Moreover, the space | interval when the target 8 and the base material 19 oppose was 200 mm.

(Comparative Example 1)
Film formation was performed in the same manner as in Example 1 except that the temperature of the deposition preventing plate 15 was not adjusted.

(Example 2)
Using the film forming apparatus having the structure shown in FIG. 1, in the first film forming region 4, a rectangular Si target 8 having a length of 145 mm in the short direction and a length of 640 mm in the long direction is set to 0 in the vacuum chamber. Sputtering is performed at 7.0 kW at .15 Pa, and in the second film formation region 6, a rectangular Nb target 12 having a length of 450 mm in the short direction and a length of 640 mm in the long direction is placed inside the vacuum chamber. Sputtering was performed at 7.0 kW at 0.15 Pa, and a total of 35 layers of SiO ₂ films and Nb ₂ O ₅ films were alternately laminated on a glass substrate having a width of 15 mm and a thickness of 1 mm.
During the film formation period, the temperature of the deposition preventing plates 15 and 16 was adjusted to 280 ° C. and 230 ° C., respectively. Moreover, the space | interval when the targets 8 and 12 and the base material 19 oppose was 200 mm.

(Comparative Example 2)
Film formation was performed in the same manner as in Example 2 except that the temperature adjustment of the adhesion preventing plates 15 and 16 was not performed.

  FIG. 2 shows the result of measuring particles generated in the vacuum chamber 1 during film formation in Example 1 and Comparative Example 1 using a particle counter (left side), and the optical thin film obtained in Example 2 and Comparative Example 2. The result (right side) of measuring the particle density after film formation is shown.

In Example 1, generation of particles having a particle diameter of 5 μm or more can be almost suppressed, whereas in Comparative Example 1, particles are generated at a rate of about 1.000 particles / cm ^2. all right.
In Example 2, the particle density with a particle diameter of 5 μm or more was about 0.010 particles / cm ² , whereas in Comparative Example 2, the particle density with a particle diameter of 5 μm or more exceeded 10.000.

  From the above results, it was found that Examples 1 and 2 can effectively prevent generation of particles in the film formation process, and the obtained optical thin film has excellent optical characteristics.

  The present invention can be widely used in the field of film formation including the field of optical thin films.

Sectional drawing in the vacuum chamber for demonstrating one embodiment of this invention (Left side) Graph showing the result of measuring particles generated in the vacuum chamber 1 during film formation in Example 1 and Comparative Example 1 with a particle counter, (Right side) Optics obtained in Example 2 and Comparative Example 2 Graph showing the result of measuring the particle density after film formation

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Base material support means 3 Rotating drum 4 1st film-forming area 5 Oxidation area 6 2nd film-forming area 7 Sputter cathode 8 Target 9 AC power supply 10 Ar gas introduction system 11 Sputter cathode 12 Target 13 AC power supply 14 Ar gas introduction system 15 Protective plate 16 Protective plate 17 Oxidation plasma source 18 Ar and O ₂ gas introduction system 19 Base material

Claims (4)

  A rotary drum capable of holding a substrate on the inner peripheral surface of the vacuum chamber is provided on the inner peripheral surface of the vacuum chamber, and a component for sputtering a metal target divided by an adhesion preventing plate in the circumferential direction of the rotary drum. An apparatus for forming an optical thin film on the base material by providing a film region and an oxidation region for oxidizing the sputtered metal thin film, allowing the base material to pass through each of the regions, An optical thin film deposition apparatus comprising a temperature control means on a deposition plate.   2. The optical thin film deposition apparatus according to claim 1, wherein an interval between the metal target and the substrate when facing each other is 120 mm to 300 mm.   A rotary drum capable of holding a substrate on the inner peripheral surface of the vacuum chamber is provided on the inner peripheral surface of the vacuum chamber, and a component for sputtering a metal target divided by an adhesion preventing plate in the circumferential direction of the rotary drum. A method for controlling an apparatus for forming an optical thin film on the substrate, comprising a film region and an oxidation region for oxidizing the metal thin film, allowing a substrate to pass through each region, When sputtering a metal target, the temperature of the said adhesion prevention board is adjusted in the range of 100 to 400 degreeC, The control method of the film-forming apparatus of the optical thin film characterized by the above-mentioned.   4. The method for controlling an optical thin film deposition apparatus according to claim 3, wherein an interval between the metal target and the base material is 120 mm to 300 mm.

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