JP2020186451A - Sputtering apparatus - Google Patents

Abstract

To provide a technology for preventing a sputtering of a vessel for accommodating a target in an apparatus for magnetron sputtering using a liquid state target.SOLUTION: A sputtering apparatus 1 according to the invention is configured such that in a target surface 8a of a liquid state target 8 a distance between a circle 17 and an inner side wall 7c of an accommodation recess 70 of a target vessel 7 is 20 mm or more, the circle being formed so as to connect points where a vertical magnetic field component of a magnetic field to a target surface 8a is zero, the magnetic field being formed by a magnet device 10.SELECTED DRAWING: Figure 1

Description

The present invention relates to a sputtering apparatus for forming a film on a substrate by sputtering in a vacuum, and particularly to an apparatus for performing magnetron sputtering using a liquid target.

In recent years, a film forming apparatus that performs sputtering using a liquid target has been proposed.

In a film forming apparatus that performs sputtering using a solid target, the target is held by bonding the solid target to the backing plate, but since bonding cannot be performed with the liquid target, the target material is stored in a dedicated container. I try to hold it.

However, in sputtering, since a voltage is applied to the target, a container having conductivity must be used, and in the prior art, there are various problems due to this.

For example, during the sputtering process, the container containing the target has the same potential as the target, so that the container itself may be sputtered.

Then, when the container is sputtered, the material of the container may enter the film to cause contamination, or the container may be damaged by erosion due to sputtering.

Japanese Unexamined Patent Publication No. 2013-125851

The present invention has been made in consideration of such problems of the prior art, and an object of the present invention is to perform sputtering of a container containing a target in an apparatus for performing magnetron sputtering using a liquid target. The purpose is to provide technology to prevent it.

The present invention made to solve the above problems is a sputtering deposition apparatus that forms a film on a substrate by magnetron sputtering using a liquid target, and is provided in a vacuum chamber and as a cathode electrode in the vacuum chamber. A target container having an accommodating recess for accommodating the liquid target, a sputtering power source for supplying a predetermined power to the target container, and a central magnet provided on the back side with respect to the accommodating recess of the target container. And a magnetron device for magnetron discharge having an outer peripheral magnet, and an inner side wall extending in a direction orthogonal to the target surface of the contained liquid target is provided in the accommodating recess of the target container, and the liquid is provided. Within the target surface of the target, the distance L between the line connecting the points where the perpendicular magnetic field component of the magnetic field formed by the magnet device to the target surface becomes zero and the inner wall surface of the accommodating recess of the target container is It is a sputtering film forming apparatus configured to be 20 mm or more.
In the present invention, among the points where the vertical magnetic field component of the magnetic field formed by the magnet device with respect to the target surface becomes zero in the target surface of the liquid target, the point closest to the inner wall surface of the target container and the said. The sputter film forming apparatus is configured such that the distance between the inner side wall and the height H of the side wall with respect to the bottom surface of the accommodating recess of the target container satisfy the relationship of L ₁ ≧ 4 H.
In the present invention, the inner side wall of the accommodating recess of the target container is formed in a circular shape, and in the magnet device, the central magnet is formed in a cylindrical shape and the outer peripheral magnet is formed in a cylindrical shape. It is a sputter film forming apparatus.
The present invention is a sputter film forming apparatus in which the inner diameter D ₁ of the inner side wall of the accommodating recess of the target container is larger than the outer diameter D ₂ of the outer peripheral magnet of the magnet apparatus by 10 mm or more.

According to the present invention, in the target surface of the liquid target, between the line connecting the points where the vertical magnetic field component of the magnetic field formed by the magnet device with respect to the target surface becomes zero and the inner wall surface of the accommodating recess of the target container. Since the distance L is configured to be 20 mm or more, the erosion region during sputtering can be kept away from the inner side wall of the accommodating recess of the target container, and as a result, the target container accommodating the liquid target. It becomes possible to prevent sputtering on, for example, the side wall portion of the accommodating recess.

In the present invention, among the points where the vertical magnetic field component of the magnetic field formed by the magnet device with respect to the target surface becomes zero in the target surface of the liquid target, the point closest to the side wall of the target container and the side wall. When the distance between the distance and the height H of the side wall with respect to the bottom surface of the storage recess of the target container are configured to satisfy the relationship of L ≧ 4H, or when the inner wall of the storage recess of the target container When the inner diameter D ₁ is configured to be 10 mm or more larger than the outer diameter D ₂ of the outer magnet of the magnet device, the erosion region during sputtering is further separated from the inner side wall of the accommodating recess of the target container. As a result, it is possible to reliably prevent sputtering on, for example, the side wall of the accommodating recess of the target container accommodating the liquid target.

(A): Partial cross-sectional view showing the internal configuration of the embodiment of the sputter film forming apparatus according to the present invention (b): Plan view showing the configuration of the magnet apparatus in the sputter film forming apparatus. (A) (b): The figure explaining the dimensional relationship of the target container and the magnet device in this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1A is a partial cross-sectional view showing an internal configuration of an embodiment of a sputtering film forming apparatus according to the present invention, and FIG. 1B is a plan view showing a configuration of a magnet apparatus according to the present embodiment. ..

The sputtering film forming apparatus 1 of the present embodiment is of a magnetron sputtering method, and has a vacuum chamber 2 having a ground potential as shown in FIG. 1A.

The vacuum chamber 2 is connected to a vacuum exhaust device 3 that performs vacuum exhaust inside the vacuum chamber 2, and is also connected to a sputter gas source 4 capable of introducing a sputter gas such as argon (Ar) gas into the vacuum chamber 2.

A disk-shaped substrate 6 held by the substrate holder 5 is arranged in the vacuum chamber 2, and a target container 7 as a cathode electrode made of a metal material is opposed to the substrate 6. Is provided.

The target container 7 of the present embodiment has a cylindrical accommodating recess 70 having an opening so that the liquid target 8 melted into a liquid state (liquid phase) is accommodated in the accommodating recess 70. It is configured in.

As the liquid target 8, a material made of a low melting point metal that can be easily liquefied can be adopted. As such a metal material, for example, gallium (Ga) alone, gallium, aluminum (Al), and indium (In) can be used. ), Magnesium (Mg), Silicon (Si), Germanium (Ge)-containing alloys.

The melting point of the material of the liquid target 8 is not particularly limited, but is preferably 250 ° C. or lower, for example.

The storage recess 70 of the target container 7 has a bottom surface 7a formed of a flat surface facing the substrate 6 and parallel to the surface of the substrate 6, and a side wall 7b for blocking the liquid target 8. There is.

The side wall 7b is provided with an inner side wall 7c formed in a curved surface (arc surface in the present embodiment) having a constant thickness on the inner portion thereof.

The inner side wall 7c extends in a direction orthogonal to the target surface 8a (and the bottom surface 7a of the storage recess 70 in the present embodiment), which is the surface of the liquid target 8 housed in the target container 7 to be sputtered. Is formed in.

In the case of the present invention, a heating mechanism (not shown) is provided in the target container 7, and a solid target material (not shown) arranged in the accommodating recess 70 of the target container 7 is heated and melted by the heating mechanism to obtain a liquid. The shape target 8 can be housed in the storage recess 70 of the target container 7.

The target container 7 is attached to the wall surface of the vacuum chamber 2 via an insulator 71, whereby the target container 7 is electrically insulated from the vacuum chamber 2.

The target container 7 is electrically connected to the power supply device 9 and is configured to supply a predetermined electric power (voltage) to the liquid target 8 via the target container 7.

The type of electric power supplied to the liquid target 8 is not particularly limited, and may be any of direct current and alternating current (including high frequency and pulsed ones).

A magnet device 10 is provided on the side opposite to the accommodating recess 70 of the target container 7 in the vacuum chamber 2.

As shown in FIGS. 1A and 1B, the magnet device 10 of the present embodiment is centered on the yoke 13 so as to generate a magnetic field above the target surface 8a of the liquid target 8. It has a magnet 11 and an outer peripheral magnet 12 installed in a continuous shape around the central magnet 11.

The central magnet 11 is formed in a cylindrical shape, and the outer peripheral magnet 12 is formed in a cylindrical shape on the yoke 13 at a certain distance from the side wall surface of the central magnet 11 and is arranged so as to surround the central magnet 11.

The central magnet 11 and the outer peripheral magnet 12 of the present embodiment are arranged concentrically with the target container 7 (accommodation recess 70).

The outer peripheral magnet 12 does not necessarily mean that it has a seamless ring shape. That is, it may be composed of a plurality of parts as long as it has a shape that surrounds the periphery of the central magnet 11.

The size of the magnet device 10 of this example is set so that the outer diameter of the outer peripheral magnet 12 (yoke 13) is smaller than the outer diameter of the target container 7.

The outer peripheral magnet 12 and the central magnet 11 are arranged so that magnetic poles having different polarities face each other with respect to the target surface 8a of the liquid target 8 housed in the housing recess 70 of the target container 7.

A moving device (not shown) of a rotating mechanism driven by a driving mechanism (not shown) is arranged on the back side of the yoke 13 of the magnet device 10, and the moving device causes the magnet device 10 to move the target surface of the target material 8. It is configured to rotate and move in parallel with 8a.

Next, regarding the present invention, the dimensional relationship between the target container 7 and the magnet device 10 will be described with reference to FIGS. 2 (a) and 2 (b).

In the present invention, in the target plane of a liquid target, between a line connecting points where the vertical magnetic field component of the magnetic field formed by the magnet device with respect to the target plane becomes zero (Gauss) and the side wall of the accommodating recess of the target container. The distance L is configured to be 20 mm or more.

In this case, the point at which the vertical magnetic field component with respect to the target surface of the liquid target becomes zero can be obtained by simulating the magnetic field characteristics of the magnetic circuit formed by the central magnet and the outer peripheral magnet of the magnet device.

In the case of the present embodiment, the inner side wall 7c of the accommodating recess 70 of the target container 7 is formed in a circular shape, and in the magnet device 10, the central magnet 11 is formed in a cylindrical shape and the outer peripheral magnet 12 is formed in a cylindrical shape. , These are arranged concentrically with the target container 7.

Therefore, in the present embodiment, as shown in FIGS. 2A and 2B, in the magnetic field 15 from the central magnet 11 to the outer peripheral magnet 12, the vertical magnetic field component of the liquid target 8 with respect to the target surface 8a becomes zero. The points 16 are located between the central magnet 11 and the outer peripheral magnet 12, respectively.

Then, as shown in FIG. 2A, the line connecting the points 16 where the perpendicular magnetic field component with respect to the target surface 8a of the liquid target 8 becomes zero is the outer peripheral magnet 12 between the central magnet 11 and the outer peripheral magnet 12. It is formed in a circular shape smaller than the inner circumference of.

When the points 16 where the vertical magnetic field component with respect to the target surface 8a of the liquid target 8 becomes zero are connected, the central magnet 11 and the outer peripheral magnet 12 of the magnet device 10 are arranged concentrically with the target container 7. A circle 17 formed concentrically with the storage recess 70 of the target container 7 is obtained.

Each part of the circle 17 is set so that the distance L between the inner side wall 7c of the storage recess 70 of the target container 7 is equal to that of the diameter direction and is 20 mm or more.

According to the present invention having such a configuration, since the erosion region during sputtering can be kept away from the inner side wall 7c of the storage recess 70 of the target container 7, the storage recess of the target container 7 that houses the liquid target 8 It becomes possible to prevent the inner side wall 7c of 70, for example, from being sputtered.

Further, in the present invention, although not particularly limited, among the points where the vertical magnetic field component of the magnetic field formed by the magnet device 10 with respect to the target surface 8a becomes zero in the target surface 8a of the liquid target 8. the distance L ₁ between the closest point and the inner wall 7c to the inner wall 7c of the target container 7, the height H of the side wall with the bottom surface 7a of the accommodation recess 70 of the target container 7, the relationship of L ₁ ≧ 4H It is preferable to configure so as to satisfy (L ₁ = L in the present embodiment).

Further, in the present invention, although not particularly limited, the inner diameter D ₁ of the inner side wall 7c of the accommodating recess 70 of the target container 7 is 10 mm or more with respect to the outer diameter D _{2 of} the magnet device 10 (outer peripheral magnet 12). It is preferable to configure it so that it becomes large.

According to the present invention having such a configuration, the erosion region during sputtering can be further separated from the inner side wall 7c of the accommodating recess 70 of the target container 7, so that the target container 7 accommodating the liquid target 8 can be accommodated. It is possible to reliably prevent, for example, the inner side wall 7c of the recess 70 from being sputtered.

The present invention is not limited to the above-described embodiment, and various modifications can be made.

For example, in the above embodiment, a case where a cylindrical accommodating recess 70, a cylindrical central magnet 11 and a cylindrical outer peripheral magnet 12 are used to perform sputtering on a disk-shaped substrate 6 will be described as an example. However, the present invention is not limited to this, and can be applied to a case where a rectangular cylinder-shaped accommodating recess, a rectangular cylinder-shaped center magnet, and a rectangular cylinder-shaped outer peripheral magnet are used to perform sputtering on a rectangular substrate. it can.

Hereinafter, examples of the present invention will be described in detail.

<Details of implementation>
Using an apparatus having the same configuration as the sputter film forming apparatus shown in FIG. 1, gallium (Ga) is placed in a housing recess of a target container made of a material containing iron (Fe), nickel (Ni), and chromium (Cr). A target material consisting of was placed.

In this case, as the target container, those having diameters of the inner side wall of the accommodating recess of 40 mm, 45 mm, 50 mm, 55 mm, 60 mm and 65 mm were used.

On the other hand, as the magnet device, one having an outer diameter of the central magnet of 25 mm and an outer diameter of the outer peripheral magnet of 50 mm was used.

Then, in the target plane of the liquid target, the diameter of the circle consisting of the lines connecting the points where the perpendicular magnetic field component with respect to the target plane of the magnetic field formed by the magnet device becomes zero is set to 30 mm.

In the sputtering process, the vacuum chamber was first evacuated, then argon gas and nitrogen gas were introduced into the vacuum chamber as the sputtering gas, and the conductance of the valve was adjusted so that the pressure became 0.1 Pa. Then, a predetermined electric power was applied to the heater in the target container to heat and melt the target material to make it liquid.

Then, an RF power of 80 W was applied to the target container as the cathode electrode, and a GaN film having a film thickness of 500 nm was formed on the substrate by controlling the film formation time using a shutter.

<Evaluation result>
After the film was formed, it was visually observed whether or not there were spatter marks on the inner wall surface of the target container.

In addition, the formed membrane was subjected to composition analysis by SIMS (secondary ion mass spectrometry).

Comprehensive judgment was as follows: ○ → no problem, × → problematic and unsuitable, △ → some problem but practical.

The above results are shown in Table 1.

As shown in Table 1, in the case where the distance L between the circle connecting the points where the perpendicular magnetic field component with respect to the target surface becomes zero and the inner wall surface of the accommodating recess of the target container is set to 10 mm and 15 mm, the target container Spatter marks were found on the inner wall surface.

Moreover, when the formed film was subjected to composition analysis by SIMS, contamination of iron (Fe), nickel (Ni), and chromium (Cr), which are constituent materials of the target container, was detected in the film.

On the other hand, the one in which the distance L between the circle connecting the points where the perpendicular magnetic field component with respect to the target surface becomes zero and the inner wall surface of the accommodating recess of the target container is set to 20 mm is the contamination of iron (Fe) in the film. Was detected.

However, no spatter marks were found on the inner wall of the target container.

Further, those in which the distances L between the circle connecting the points where the perpendicular magnetic field component with respect to the target surface becomes zero and the inner wall surface of the accommodating recess of the target container are set to 25 mm, 30 mm, and 35 mm are contamination in the film. Was not detected, and no spatter marks were found on the inner wall of the target container.

From the above results, a liquid target is used by setting the distance L between the circle connecting the points where the vertical magnetic field component with respect to the target surface becomes zero and the inner wall surface of the accommodating recess of the target container to 20 mm or more. It has been clarified that in a device that performs magnetron sputtering, sputtering on a container containing a target can be prevented.

1 ... Sputter film forming apparatus 2 ... Vacuum tank 6 ... Substrate 7 ... Target container 7a ... Bottom surface 7b ... Side wall 7c ... Inner side wall 8 ... Liquid target 8a ... Target surface 10 ... Magnet device 11 ... Central magnet 12 ... Outer magnet 70 ... Containment recess

Claims (4)

A sputter film forming apparatus that uses a liquid target to form a film on a substrate by magnetron sputtering.
With a vacuum tank
A target container provided as a cathode electrode in the vacuum chamber and having a storage recess for containing the liquid target, and a target container.
A sputtering power supply that supplies a predetermined electric power to the target container, and
It is provided on the back side with respect to the accommodating recess of the target container, and is provided with a magnet device for magnetron discharge having a central magnet and an outer peripheral magnet.
The storage recess of the target container is provided with an inner side wall extending in a direction orthogonal to the target surface of the stored liquid target.
The distance between the line connecting the points in the target surface of the liquid target where the vertical magnetic field component of the magnetic field formed by the magnet device with respect to the target surface becomes zero and the inner wall surface of the accommodating recess of the target container. A sputter film forming apparatus configured so that L is 20 mm or more. In the target surface of the liquid target, among the points where the vertical magnetic field component of the magnetic field formed by the magnet device with respect to the target surface becomes zero, the point closest to the inner wall surface of the target container and the inner wall surface. The spatter film forming apparatus according to claim 1, wherein the distance between the two walls and the height H of the side wall with respect to the bottom surface of the accommodating recess of the target container are configured to satisfy the relationship of L ₁ ≧ 4 H. Claim 1 or claim 1, wherein the inner side wall of the accommodating recess of the target container is formed in a circular shape, the central magnet is formed in a cylindrical shape, and the outer peripheral magnet is formed in a cylindrical shape in the magnet device. 2. The sputter film forming apparatus according to any one of 2. The invention according to any one of claims 1 to 3, wherein the inner diameter D ₁ of the inner side wall of the accommodating recess of the target container is configured to be 10 mm or more larger than the outer diameter D ₂ of the outer peripheral magnet of the magnet device. Sputter film forming equipment.

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