JPH0578831A - Formation of thin film and device therefor - Google Patents

Abstract

(57) [Summary] [Structure] In a thin film formation method by sputtering, a pair of targets are arranged in a vacuum chamber so as to be inclined with respect to the substrate so as to increase the mutual distance as they approach the substrate. A thin film forming method characterized by forming a thin film on a substrate while simultaneously applying an electric field to generate electric discharge and applying a magnetic field so that magnetic force lines pass through the target. A voltage for applying a voltage to a supporting means for supporting a substrate in a vacuum chamber and a pair of targets arranged to be inclined with respect to the substrate so as to widen the mutual distance as the substrate is approached to cause sputtering. A thin film forming apparatus comprising: an applying unit and a magnetic field applying unit that applies a magnetic field from one target to the other target. [Effect] A uniform and dense thin film can be formed on a substrate at a high film formation rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for forming a thin film, and more particularly to a method and apparatus for forming a uniform and dense thin film on a substrate at a high film forming rate.

[0002]

BACKGROUND OF THE INVENTION A thin film forming method utilizing a spattering phenomenon (hereinafter referred to as a sputtering method) is capable of relatively easily forming a film even with a high melting point material or compound which is difficult to deposit, and is easy to increase the area. It is widely used for various reasons. However, the sputtering method has a disadvantage that the film forming rate is slower than that of the vapor deposition method. Therefore, as a method for improving the film formation rate, a triode sputtering method provided with a plasma generation electrode, a magnetron sputtering method, and the like have been proposed and implemented.

In the magnetron sputtering method, secondary electrons (γ electrons) and negative ions which adversely affect thin film formation are confined in the vicinity of the target by applying a magnetic field to protect the substrate and at the same time promote ionization of the atmosphere to increase the plasma density. A good quality thin film can be formed, and the film forming speed can be improved. However, even with such a magnetron sputtering method, the film formation rate is slower than that of the vapor deposition method, and when sputtering a ferromagnetic substance, a strong magnetic field is generated to create an effective magnetic field near the target. However, there is a drawback in that the erosion of the target locally occurs and the use efficiency of the target is reduced.

As a method of improving these drawbacks, there is a facing type sputtering method. The opposed sputtering method is a method in which a pair of targets having the same size are opposed to each other and a magnetic field and an electric field are applied in parallel from one target to the other target to deposit sputtered particles laterally. However, the facing sputtering method has a drawback in that sputtered particles are isotropically scattered between the targets in all directions and the loss of the thin film material is large.

[0005]

An object of the present invention is to solve the above problems in the prior art, and to provide a method and a method capable of forming a uniform and dense thin film on a substrate at a high film forming rate. It is intended to provide the device.

[0006]

SUMMARY OF THE INVENTION A thin film forming method according to the present invention is a thin film forming method by sputtering, in which a pair of targets are tilted with respect to a substrate so as to widen the mutual distance as they approach the substrate. It is characterized in that a thin film is formed on the substrate while arranging and applying an electric field to the above target to generate a discharge and at the same time applying a magnetic field so that magnetic force lines pass through both targets.

A thin film forming apparatus according to the present invention comprises a support means for supporting a substrate in a vacuum chamber, and a pair of slanting members arranged so as to widen the mutual distance as the substrate is approached. It is characterized by comprising a voltage applying means for applying a voltage to the target to cause sputtering and a magnetic field applying means for applying a magnetic field from one target to the other target.

[0008]

DETAILED DESCRIPTION OF THE INVENTION A thin film forming method and apparatus according to the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is an example of a thin film forming apparatus according to the present invention, and FIG. 2 is a conceptual diagram of the thin film forming apparatus according to the present invention. As shown in FIG. 1, in this thin film forming apparatus 1, a substrate supporting portion 3 is provided above the inside of a vacuum chamber 11, and a substrate 2 to which a thin film is attached is attached to this substrate supporting portion 3. There is. The distance between the substrate 2 and the target can be adjusted by the substrate position adjusting mechanism 8.

In the present invention, the substrate 2 may be an inorganic material such as metal, alloy, glass, ceramics or single crystal, or may be an organic material such as plastic.
Targets 4 and 4 ′ are provided below the inside of the vacuum chamber 11. The targets 4 and 4'are arranged so as to incline with respect to the substrate and incline with respect to the substrate so as to increase the mutual distance as they approach the substrate. As shown in FIG. 2, it is preferable that the targets 4 and 4 ′ are installed symmetrically with respect to a plane P that passes through the center of the substrate 2 and is orthogonal to the substrate 2. It is preferably parallel to the line. Further, it is preferable that the targets 4 and 4 ′ have the same shape and the same size.

The targets 4, 4'include an angle adjusting mechanism 5,
The tilt angles θ and θ ′ can be adjusted by 5 ′, and the distance between the targets 4 and 4 ′ and the distance between the targets 4 and 4 ′ and the substrate can be adjusted by the target position adjusting mechanism 7. Note that the target tilt angle θ,
θ'is the plane P orthogonal to the substrate 2 and the targets 4, 4 '
And the inclination angles θ and θ ′ are preferably substantially the same.

A power source (not shown) for the targets 4 and 4 '
Are connected so that a voltage can be applied. The target is the cathode and the substrate is usually kept at ground potential.

As the target, metal, alloy, inorganic oxide, inorganic simple substance, etc. are preferably used. Permanent magnets 6 and 6'as magnetic field applying means are provided on the lower left and right sides inside the vacuum chamber 11. The permanent magnets 6 and 6'are installed on the back surface side of the target so that the magnetic field is applied in a direction substantially parallel to the straight line ab passing through the centers of the targets 4 and 4'and the magnetic force lines pass through both targets. ing.

Although a permanent magnet is used as the magnetic field applying means in this embodiment, a coil may be used as the magnetic field applying means in the present invention. Also, one or more permanent magnets 6 and 6'can be used respectively, and the permanent magnets 6, 6 '
6 ′ is preferably the same number. The magnetic field applying means is 200 gauss or more, preferably 2 near the center of the plasma region.
It is desirable to use a permanent magnet or a coil that applies a magnetic force of 50 Gauss or more.

In FIG. 1, 9 is an exhaust pipe and 10 is a gas introduction pipe. In order to form a thin film using the thin film forming apparatus 1 as described above, the substrate 2 is first mounted on the substrate supporting portion 3.

Next, after mounting the targets 4 and 4 ',
The pressure inside the vacuum chamber 11 is reduced to 1 × 10 ⁻⁶ to 1 × 10 ⁻⁸ Torr. The tilt angles θ and θ ′ of the targets 4 and 4 ′ are 20 ° to
It is desired to be in the range of 80 °, preferably 40 ° to 70 °.

Next, the sputtering gas is introduced through the gas introduction pipe. As sputter gas, argon, krypton,
Helium, neon, etc. are used. When reactive sputtering is performed, a reactive gas such as oxygen gas, nitrogen gas, methane or silane can be mixed with the sputtering gas.

The degree of vacuum in the vacuum chamber 11 is 1 × 10 ⁻⁴ to 2 × 1 while introducing a fixed amount of sputtering gas into the vacuum chamber 11.
0 ^-2 Torr, preferably 1 x 10 ^-3 to 1 x 10 ^-2 To
It is desirable to set it to rr.

Next, a DC voltage is applied to the targets 4, 4 '. In the present invention, only the DC voltage may be applied to the targets 4 and 4 ′, the high frequency voltage may be applied while being superimposed on the DC voltage, or only the high frequency voltage may be applied.
At this time, the voltage of the DC component generated in the target is 0.3 to
It is desirable that the voltage is 3 kV, preferably 0.5-2 kV.

By applying a voltage to the target in this way, glow discharge occurs. This glow discharge forms plasma in the discharge space. The positive ions in this plasma are accelerated by the cathode potential drop in the vicinity of the cathode, collide with the target cathode surface, and sputter evaporate the target surface. The sputtered thin film forming material is deposited on the substrate to form a thin film.

[0021]

According to the thin film forming method and apparatus of the present invention, in the thin film forming method by sputtering,
In the vacuum chamber, a pair of targets are arranged so as to be inclined with respect to the substrate so that the distance between them increases as they get closer to the substrate. A thin film is formed on the substrate while applying a magnetic field so as to pass through. For this reason,
Since secondary electrons (γ electrons) and negative ions can be confined between the targets and the sputtering rate in the substrate direction can be improved, it is possible to reduce the plasma density between the targets by the conventional sputtering method. In comparison, the film formation rate can be significantly improved.

Further, the residual gas content in the thin film can be reduced, and the thin film can be densified and homogenized. Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

[0023]

Example 1 A glass plate was attached as a substrate to an apparatus as shown in FIG. 1, iron was used as a target, and its inclination angle θ was set to 60 °. As a magnetic field applying means, a permanent magnet was installed such that a magnetic force of 200 gauss or more was applied near the center of the plasma region.

The inside of the vacuum chamber 11 was evacuated, the degree of vacuum in the vacuum chamber was set to 5 × 10 ⁻⁷ Torr, and then argon gas was supplied at 7 minutes per minute.
A quantity of 5 cc was introduced into the vacuum chamber. A film was formed for 60 seconds while using a target as a cathode and applying a direct current of 2 kV. The degree of vacuum during film formation was 5.5 × 10 ⁻³ Torr.

The thickness and density of the thin film deposited on the center of the substrate thus formed were measured. The results are shown in Table 1.

[0026]

Examples 2 to 3 In Example 1, the film having the target tilt angle θ of 45 ° was made into Example 2 and the film having the target inclination angle θ of 30 ° was made into Example 3, and the film was formed in the same manner as in Example 1. The results are shown in Table 1.

[0027]

[Comparative Examples 1 and 2] In Example 1, a target having a tilt angle θ of 0 ° was set as Comparative Example 1, and a target having a tilt angle θ of 90 ° was set as Comparative Example 2, and the same as in Example 1. A film was formed. The results are shown in Table 1.

[0028]

[Table 1]

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a thin film forming apparatus according to the present invention.

FIG. 2 is a conceptual diagram of a thin film forming apparatus according to the present invention.

[Explanation of symbols]

 1 thin film forming apparatus 2 substrate 4, 4'target 5, 5'angle adjusting mechanism 6, 6'permanent magnet 7 target position adjusting mechanism θ, θ'tilt angle

Claims (2)

[Claims] 1. A method for forming a thin film by sputtering, wherein a pair of targets are arranged in a tilted manner with respect to a substrate so as to increase the mutual distance as they approach the substrate, and a voltage is applied to the target. A thin film forming method is characterized in that a thin film is formed on a substrate while generating a discharge and applying a magnetic field so that magnetic force lines pass through both targets. 2. A voltage is applied to a support means for supporting a substrate in a vacuum chamber and a pair of targets arranged so as to be inclined with respect to the substrate so as to widen the mutual distance as they approach the substrate. A thin film forming apparatus comprising: a voltage applying unit that causes sputtering and a magnetic field applying unit that applies a magnetic field from one target to the other target.