JPH0874048A - Sputtering device - Google Patents

Abstract

PURPOSE: To improve a flange for hermetic insulation by raising the vacuum degree of a vacuum chamber of a cathode sputtering device to a desired value. CONSTITUTION: This sputtering device includes a cathode section 2 which is mounted with a target 1 of a metallic material for thermal spraying and is connected by a circuit to the negative pole of a DC power source 6 and an anode section 5 which is mounted with a sample 4 and is connected by a circuit to the positive pole of the DC power source 6. Either of the cathode section and anode section is constituted attachable and detachable to and from the other. The circumference therebetween is insulated and the target 1 and the sample 4 are arranged to face each other apart a prescribed spacing. The insulating part between the cathode section 2 and anode section 5 of the cathode sputtering device formed to regulate the evacuatable vacuum chamber 11 is composed of the annular insulating flange 13 having a relatively small thickness and an O-ring 12 consisting of synthetic rubber provided with a notch 12a fitting to the inner peripheral edge of the insulating flange from the outer part to the central part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering apparatus used for forming a metal thin film, and more particularly to a sputtering apparatus having an insulating flange structure for insulation and hermetic sealing of PVD or the like. Integrated circuit (IC), large integrated circuit (LS
Semiconductor devices such as I) are manufactured by using a thin film forming technique, a photolithography technique (photographing), an impurity element implantation technique, and the like. Among them, the thin film forming technique is divided into a physical technique such as vacuum deposition and sputtering and a chemical technique such as plating. In the physical thin film forming technology, the vacuum evaporation method is a universal method for forming a thin metal film, but the metal to be coated is limited to a simple metal having a relatively low melting point, whereas the sputtering method The law is
Since it is possible to form a thin film of a metal or alloy having a relatively high melting point such as tungsten (W) or tantalum (Ta), it is widely used as a means for forming wiring, electrodes, etc. in the manufacturing process of semiconductor devices.

[0002]

2. Description of the Related Art An example of a conventional sputtering apparatus will be described with reference to the drawings. FIG. 3 is a cross-sectional view showing the structure of the magnetron sputtering apparatus. The target 1 made of a material for spraying a thin film is made of a non-magnetic metal such as copper (Cu) having a water-cooled structure (not shown). Nari and DC power supply 6
Is attached downward to the cathode part 2 which is connected to the negative electrode of the circuit,
An electromagnet 3 is provided on the upper side of the cathode portion 2. on the other hand,
A sample 4 on which a thin film is to be formed is placed on an anode part 5 made of a metal such as stainless steel so as to face the target 1 at a predetermined interval, and a circuit is connected to the positive electrode of a DC power source 6 as shown in the figure. It is connected. In order to insulate the cathode part 2 and the anode part 5 from each other, a flange 7 made of an insulating material such as Teflon (trade name) is interposed, and between the flange 7 and the cathode part 2 and the anode part 5. The O-rings 8 and 9 made of fluororubber or the like are arranged to hermetically seal between the cathode portion 2 and the anode portion 5.

That is, an exhaust system is used to evacuate from the exhaust port 10 to evacuate the inside of the apparatus to a high vacuum to form a vacuum chamber 11, and a needle pipe (not shown) is passed through the vacuum chamber 11. An inert gas such as argon (Ar) is supplied, and a voltage is applied from the DC power supply 6 while maintaining the vacuum chamber 11 of the apparatus at a predetermined pressure of several milliTorr to generate plasma between the cathodes 5 and 2. The sputtering phenomenon is generated by causing the inert gas ions to collide with the target 1 by being generated.

Here, the conditions necessary to obtain a good quality sputtered thin film on the sample 4 without oxidization or the like are that the inside of the vacuum chamber 11 of the sputtering apparatus can be maintained at a high vacuum and the atmospheric leak from the outside. There is nothing. However, the conventional sputtering apparatus has a problem in this respect. That is, initially, the exhaust port 1
After evacuating the vacuum chamber 11 to a high vacuum of 10 ^-8 to 10 ^-9 Torr by 0, a high-purity inert gas is supplied into the vacuum chamber 11 and sputtering is performed in an inert gas atmosphere of several milliTorr. There is a need.

In order to maintain the insulation between the cathodes 5 and 2, the flange 7 disposed at the peripheral butting portion between the cathode portion 2 and the anode portion 5 is made of a fluororesin (polytetrafluoroethylene, trade name: It is customary to perform vacuum sealing using O-rings 8 and 9 made of fluororubber, which are made of Teflon and are arranged on the joining surfaces of the cathode portion 2 and the anode portion 5 on the upper and lower surfaces of the flange 7. When the combination is taken, the degree of vacuum is raised only by about 10 ⁻⁶ to 10 ⁻⁷ Torr at the initial high vacuum exhaust,
Since there is some air leakage, there is a problem in the reliability of the sputtered film, and improvement is needed.

[0006]

As described above, a high DC voltage is applied between the cathode 2 and the anode 5 of the sputtering apparatus in order to generate a plasma of an inert gas.
In the structure in which the cathode portion 2 and the anode portion 5 are opposed to each other as shown in FIG. 2, conventionally, a flange 7 made of an insulating portion is interposed between the opposed portions, and the flange 7 is sandwiched between two O-rings 8 and 9 from above and below. The structure was used for vacuum sealing.

Here, the flange 7 used for insulation
Fluorine resin (polytetrafluoroethylene,
Product name: Teflon) is the best material used for insulation as an organic compound, and fluorine rubber, which is the material for the O-rings 8 and 9, is a generic name for synthetic rubber containing fluorine and is more heat resistant than silicone rubber. It has excellent chemical resistance and is considered to be the best material for the O-ring. Therefore, the elucidation of the reason why the degree of vacuum does not increase with this combination and the countermeasure against it have been the problems.

Therefore, according to the present invention, an insulating flange or an O
An object of the present invention is to provide a cathode sputtering apparatus capable of increasing the degree of vacuum in a vacuum chamber to a desired value by improving the structure or shape of the ring.

[0009]

According to a first aspect of the present invention, in order to achieve the above object, a target of a sprayed metal material is mounted and connected to a first power source (negative electrode of a DC power source) by a circuit. The first electrode part (cathode part) and the sample are placed and the second
And a second electrode portion (anode portion) circuit-connected to the power source (the positive electrode of the DC power source), and one of the cathode portion and the anode portion is configured to be attachable to and detachable from the other. In the sputtering apparatus, the surroundings are insulated from each other to define an evacuable vacuum chamber in which the target and the sample are arranged to face each other with a predetermined gap.
The insulating portion between the electrodes (cathode portion and anode portion) is a ring-shaped insulating flange, and a rubber O-ring in which a notch that fits into the inner peripheral edge portion of the insulating flange is provided from the outside to the central portion. A sputtering apparatus is provided which is characterized in that

According to a second aspect, in the first aspect, the insulating flange is made of a fluororesin, particularly polytetrafluoroethylene. According to a third aspect, in the first or second aspect, the O-ring is made of fluororubber.

[0011]

[Function] Fluorine resin, especially polytetrafluoroethylene (trade name: Teflon) (hereinafter referred to as Teflon) is generally used as a constituent material of the insulating flange for spatter, but in addition to this, alumina (Al ₂ Ceramics such as O ₃ are also used.However, although the flange made of ceramics can secure the degree of vacuum, it is fragile and easily damaged when tightening screws, and it is expensive and has a practical problem. , Teflon is better.

[0012] This Teflon has a high insulating power and is an excellent resin, but on the other hand it has excellent chemical resistance and is insoluble in most organic solvents. Is taken. Therefore, it is known that fine pinholes are present on the surface, a leak is likely to occur at a portion in contact with the O-ring, and various gases are generated by evaporation at a high temperature (250 ° C. or higher).

Therefore, in the present invention, the thickness of the ring-shaped insulating flange is made relatively thin, a notch is provided from the outside to the center of the O-ring made of synthetic rubber, and the inner edge of the insulating flange is provided with the notch of the O-ring. Is fitted to. With such a structure, only the O-ring is on the side facing the vacuum chamber, and even if the temperature inside the vacuum chamber becomes high, the insulating flange itself does not come into direct contact with the high temperature atmosphere, so that problems such as evaporation do not occur. High insulation can be maintained.

[0014]

Embodiments of the present invention will be described in detail below with reference to FIGS. FIG. 1 is a schematic sectional view showing the structure of a cathode sputtering apparatus according to the present invention.
(A), (B) and (C) show insulating flanges used in the cathode sputtering apparatus of the present invention.

In FIG. 1, 1 is a target of a sprayed metal material, 2 is a cathode part on which this target 1 is mounted, 3 is an electromagnet, 4 is a sample on which a metal thin film is formed by spraying, 5
Is an anode part on which this sample is placed, and 6 is a DC power supply. One of the cathode part 2 and the anode part 5 is configured to be detachable from the other. A vacuum chamber 11 is formed by exhausting from the exhaust port 10, and inside the vacuum chamber 11, the target 1 and the sample 4 are arranged to face each other with a predetermined interval. The following structure is the same as that of the conventional cathode sputtering apparatus.

The insulating portion between the cathode portion 2 and the anode portion 5 is, as shown in FIGS. 1 and 2, a ring-shaped insulating flange 13 having a relatively thin thickness and an inner peripheral edge portion of the insulating flange 13. The groove that fits in is provided from the outside to the center,
It is composed of an O-ring 12 made of synthetic rubber. That is, an O-ring 12 made of fluororubber having a circular cross section with a diameter of 10 mm was processed to form a hole with a diameter of 1 mm at the center, and a cut 12a was made outward from the center. Also, the thickness is 1
The thickness of the inner edge portion 13a of the flange 13 made of Teflon having a diameter of 2 mm was expanded to 2 mm and fitted to the center of the O-ring 12.

Tungsten (W) is used as the target 1 and a silicon (Si) wafer provided with an insulating layer of silicon dioxide (SiO ₂ ) is used as the sample 4, and an exhaust system (not shown) is operated to exhaust gas. As a result of exhausting from the mouth 10,
It was possible to easily evacuate to a vacuum degree of 10 ^-9 Torr, and no leak was observed. FIG. 4 is a diagram comparing vacuum characteristics of insulating flange portions. The flange of the conventional example shown by the broken line is the characteristic when the flange 7 (and the two O-rings 8) in the conventional cathode sputtering apparatus shown in FIG. 3 is used, and after the vacuum exhaust by the turbo pump is started, Even after 10 hours, only a vacuum degree of about 10 ^-7 to 10 ^-8 Torr was obtained.

The flange of the embodiment shown by the solid line is a vacuum characteristic when the flange 13 (and one O ring 12) shown in FIGS. 1 and 2 is used, and after the vacuum is started by the turbo pump under the same conditions. After 10 hours to 100 hours, a vacuum degree of about 10 ⁻⁸ to 10 ⁻⁹ Torr is obtained.
Next, through a needle valve (not shown), argon (A
r) was introduced in small amounts and was evacuated to maintain a vacuum degree of 5 mmTorr, and 8 kW of electric power was supplied between the electrode parts 2 and 5 to perform magnetron sputtering. (W) The film could be obtained.

As described above, according to the embodiment of the present invention,
A notch groove 12a is formed from the outside of the O-ring 12 having a hole made of fluororesin to the center, and a Teflon flange 13 having an inner edge 13a bulging is inserted into the hole through the notch 12a. Is placed as close to the vacuum chamber 11 as possible, and a Teflon flange 13 is inserted from the outside, and the outer edge portion of the flange 13 is at least from the outer edges of the cathode portion 2 and the anode portion 5.
3b and 13c (Fig. 2 (c)) are exposed. In this way, the O-ring 12 faces the vacuum chamber 11.
Therefore, the vacuum can be maintained, while the flange 13 made of Teflon is interposed between the cathode part 2 and the anode part 5, so that the electrical insulation can be completely maintained.

[0020]

As described above, in the cathode sputtering apparatus using the insulating flange according to the present invention, it is possible to eliminate the leak through the insulating flange, thereby increasing the degree of vacuum and forming a good quality thin film without oxidation. It is possible to improve reliability.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a cathode sputtering apparatus to which the present invention is applied.

FIG. 2 is a plan view (A), a sectional view (B), and a partially enlarged view (C) of an insulating flange used in the cathode sputtering apparatus of the present invention.

FIG. 3 is a sectional view showing a configuration of a conventional cathode sputtering apparatus.

FIG. 4 is a diagram showing a comparison of vacuum characteristics of a vacuum chamber in a conventional example and an example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Target 2 ... Cathode part 4 ... Sample 5 ... Anode part 11 ... Vacuum chamber 7,13 ... Flange 8, 9, 12 ... O-ring 12a ... Notch

Claims (3)

[Claims] 1. A first electrode part (2) mounted with a target (1) of a sprayed metal material and circuit-connected to a first power source.
And a second electrode portion (5) on which a sample (4) is placed and which is circuit-connected to a second power source, and one of the first and second electrode portions is provided with respect to the other. And a detachable vacuum chamber (11) in which the target (1) and the sample (4) are opposed to each other with a predetermined distance therebetween, and the surroundings are insulated. In the sputtering device, the insulating portion between the first and second electrode portions has a ring-shaped insulating flange (13) and a notch (12a) fitted to the inner peripheral edge of the insulating flange from the outside to the center. Rubber O-ring (12) installed over
And a cathode sputtering device. 2. Sputtering device according to claim 1, characterized in that the insulating flange (13) is made of a fluororesin, in particular polytetrafluoroethylene. 3. The sputtering apparatus according to claim 1, wherein the O-ring (12) is made of fluororubber.