JP7584735B2 - Sputtering Equipment - Google Patents

Description

The present invention relates to a sputtering device that uses plasma to sputter a target and form a film on a workpiece.

As shown in Patent Document 1, a conventional sputtering device has an antenna placed outside a vacuum vessel, and a high-frequency magnetic field generated from this antenna is transmitted into the vacuum vessel via a dielectric plate attached to the outer wall of the vacuum vessel, thereby generating plasma inside the vacuum vessel, which sputters the target and forms a film on the workpiece.

In this way, a configuration in which the antenna is disposed outside the vacuum vessel allows the target to be closer to the workpiece, improving the film formation speed and processing efficiency, compared to a configuration in which the antenna is disposed inside the vacuum vessel. In addition, by disposing the antenna outside the vacuum vessel, sputtered particles do not adhere to the antenna, which reduces dirt and shortens its lifespan, and further simplifies the antenna mounting structure, providing various other advantageous effects.

However, when the antenna is placed outside the vacuum vessel, as shown in Figure 5 (A), if the antenna is placed behind the sputtering surface of the target, the high-frequency magnetic field extending from the antenna cannot be efficiently guided to the sputtering surface, resulting in poor sputtering efficiency.

The inventors therefore came up with an intermediate configuration midway through the development of the present invention, in order to improve sputtering efficiency while still placing the antenna outside the vacuum vessel, as shown in Figure 5 (B), in which the outer wall of the vacuum vessel is recessed outward, the target is placed at the bottom of this recess, and the antenna is placed so that it faces the dielectric plate on the side wall. With this configuration, the antenna can be positioned forward of the sputtering surface of the target, improving sputtering efficiency.

However, the configuration shown in Figure 5(B) increases the distance from the target to the workpiece, reducing the deposition speed and processing efficiency, and diminishing the benefits of placing the antenna outside the vacuum vessel.

JP 2000-226655 A

The present invention was developed to solve all of the above problems at once, and its main objective is to enable efficient sputtering of the target while improving film formation speed and processing efficiency by shortening the distance from the target to the workpiece by placing an antenna outside the vacuum vessel.

That is, the sputtering apparatus according to the present invention is a sputtering apparatus that uses plasma to sputter a target to form a film on a workpiece, and is equipped with a vacuum vessel that is evacuated to a vacuum, an antenna provided outside the vacuum vessel, a dielectric plate provided on the outer wall of the vacuum vessel in a position facing the antenna, and a target holder that holds the target within the vacuum vessel, characterized in that the target is provided at one or both of the positions that sandwich the dielectric plate, and the sputtering surface extends obliquely toward the opposite side of the antenna relative to the dielectric plate.

In a sputtering apparatus configured in this manner, the sputtering surface of the target extends obliquely toward the opposite side of the antenna with respect to the dielectric plate, so that the high-frequency magnetic field extending from the antenna can be efficiently guided to the sputtering surface.
As a result, in a configuration in which an antenna is provided outside a vacuum vessel, the distance to the workpiece can be shortened, thereby enabling efficient sputtering of the target while improving the film formation rate and processing efficiency.
Furthermore, by slanting the sputtering surface, the spread of sputtered particles onto the workpiece can be suppressed, and the utilization rate of the sputtering source can be increased.

In order to further improve the deposition speed and processing efficiency, it is preferable that the targets are provided at both positions that sandwich the dielectric plate, and that each of the sputtering surfaces of the targets extends obliquely toward the opposite side of the antenna relative to the dielectric plate.

To achieve the above-mentioned effects more significantly, it is preferable that the inclination angle of the sputtering surface of the target with respect to the dielectric plate is 10 degrees or more and 45 degrees or less.

It is preferable that the dielectric plate is placed on a slit plate having a plurality of slits formed therein.
In this configuration, the magnetic field transmission window is formed by overlapping the slit plate and the dielectric plate, so the thickness of the magnetic field transmission window can be made smaller than when only the dielectric plate functions as the magnetic field transmission window. This makes it possible to shorten the distance from the antenna to the inside of the vacuum vessel, and to efficiently supply the high frequency magnetic field generated by the antenna into the vacuum vessel.

According to the present invention configured in this way, by placing an antenna outside the vacuum vessel and shortening the distance from the target to the workpiece, it is possible to efficiently sputter the target while improving the film formation speed and processing efficiency.

FIG. 1 is a schematic diagram showing a configuration of a sputtering apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the arrangement of targets in the sputtering apparatus of the present embodiment. FIG. 13 is a schematic diagram showing the configuration of a sputtering apparatus according to another embodiment. FIG. 13 is a schematic diagram showing the configuration of a sputtering apparatus according to another embodiment. FIG. 1 is a schematic diagram showing a configuration that was intermediately investigated on the way to achieving the present invention.

Below, one embodiment of a sputtering device according to the present invention will be described with reference to the drawings.

<Device Configuration>
The sputtering apparatus 100 of this embodiment sputters a target T by using an inductively coupled plasma P to form a film on a workpiece W such as a substrate. Here, the workpiece W is, for example, a substrate for a flat panel display (FPD) such as a liquid crystal display or an organic electroluminescence display, a flexible substrate for a flexible display, or the like.

Specifically, as shown in Figures 1 and 2, the sputtering device 100 includes a vacuum vessel 1 forming a processing chamber S that is evacuated and into which gas is introduced, a substrate holder 2 that holds a workpiece W in the processing chamber S, a target holder 3 that holds a target T in the processing chamber S, a target bias power supply 4 that applies a bias voltage to the target T, an antenna 5 provided outside the vacuum vessel 1, a dielectric plate 6 provided on the outer wall of the vacuum vessel 1 at a position facing the antenna, and a high-frequency power supply 7 that applies high-frequency waves to the antenna 5. With this configuration, high-frequency current flows through the multiple antennas 5 by applying high-frequency waves from the high-frequency power supply 7 to the antenna 5, generating an induced electric field in the vacuum vessel 1 and generating an inductively coupled plasma P.

The vacuum vessel 1 is, for example, a metal vessel, and its interior is evacuated to a vacuum by a vacuum exhaust device 8. In this example, the vacuum vessel 1 is electrically grounded.

A sputtering gas or a reactive gas is introduced into the vacuum vessel 1 from a gas supply mechanism 9 having, for example, a flow rate regulator (not shown) through a gas inlet 10. The sputtering gas and the reactive gas may be selected according to the processing to be performed on the workpiece W. The sputtering gas is, for example, an inert gas such as argon (Ar), and the reactive gas is, for example, oxygen ( _O2 ) or nitrogen ( _N2 ).

The substrate holder 2 is a holder that holds the flat workpiece W in the vacuum chamber 1, for example in a horizontal position. In this example, the holder is electrically grounded.

The target holder 3 holds the target T facing the workpiece W held by the substrate holder 2. In this embodiment, the target T is a flat plate having a rectangular shape in a plan view. The target holder 3 is provided on the outer wall (e.g., the upper wall) 1a that forms the vacuum vessel 1. In addition, an insulating part 31 having a vacuum sealing function is provided between the target holder 3 and the upper wall 1a of the vacuum vessel 1.

In this embodiment, multiple target holders 3 are provided, specifically a pair of target holders 3 positioned to sandwich the antenna 5 described below.

The target bias power supply 4 is connected to the target T via the target holder 3, and applies a bias voltage to the target T. This bias voltage is a voltage that attracts ions in the plasma P to the target T and causes sputtering. Note that here, a common target bias power supply 4 is connected to a pair of targets T, but separate target bias power supplies 4 may be connected to each target T.

The antenna 5 is for generating plasma P in the processing chamber S, and is linear, for example, having a length of several tens of centimeters or more. In this embodiment, as shown in FIG. 1, one antenna 5 is disposed between a pair of targets T. Here, the longitudinal direction of the antenna 5 and the longitudinal direction of each target T are in the same direction, and the antenna 5 is disposed so as to be equidistant from each target T.

The material of each antenna 5 is, for example, copper, aluminum, alloys thereof, stainless steel, etc., but is not limited to these. The antenna 5 may be hollow and a refrigerant such as cooling water may be run through it to cool the antenna 5.

A high-frequency power source 7 is connected to one longitudinal end of the antenna 5 via a matching circuit 71, and the other longitudinal end is directly grounded. An impedance adjustment circuit such as a variable capacitor or variable reactor may be provided at one or the other end of the antenna 5 to adjust the impedance of each antenna 5. By adjusting the impedance of each antenna 5 in this manner, the density distribution of the plasma P in the longitudinal direction of the antenna 5 can be made uniform, and the film thickness in the longitudinal direction of the antenna 5 can be made uniform.

The above configuration allows a high-frequency current to flow from the high-frequency power source 7 to the antenna 5 via the matching circuit 71. The frequency of the high-frequency current is, for example, a typical 13.56 MHz, but is not limited to this.

The dielectric plate 6 constitutes a magnetic field transmission window that allows the high-frequency magnetic field generated by the antenna 5 to pass into the processing chamber S, and is arranged to cover an opening formed in the outer wall (here, the upper wall) 1a of the vacuum vessel 1.

The dielectric plate 6 here is rectangular when viewed from the antenna 5 side, and is arranged so that its longitudinal direction is the same as the longitudinal direction of each target T. Materials constituting the dielectric plate 6 include ceramics such as alumina, silicon carbide, and silicon nitride, inorganic materials such as quartz glass and non-alkali glass, and resin materials such as fluororesin (e.g., Teflon).

The sputtering device 100 of this embodiment is characterized in that the sputtering surface Ta of the target T extends obliquely toward the opposite side of the antenna 5 with respect to the dielectric plate 6, as shown in Figures 1 and 2.

To explain in more detail, the sputtering surface Ta of the target T is inclined so as to approach the workpiece W held by the substrate holder 2 as it moves away from the dielectric plate 6. Specifically, as shown in FIG. 2, the inclination angle θ of the sputtering surface Ta of the target T with respect to the dielectric plate 6 is 10 degrees or more and 45 degrees or less. Note that the inclination angle θ here is the acute angle of the intersection angle between the sputtering surface Ta and the surface 61 of the dielectric plate 6 facing the workpiece W in a configuration in which the sputtering surface Ta moves closer to the workpiece W as it moves away from the dielectric plate 6.

In this embodiment, each of the sputtering surfaces Ta of the pair of targets T extends obliquely toward the opposite side of the antenna 5 with respect to the dielectric plate 6. The pair of targets T are arranged linearly symmetrically with respect to the dielectric plate 6, and more specifically, are arranged in a V-shape expanding from the dielectric plate 6 side toward the workpiece W side. In other words, the pair of targets T are arranged so that their sputtering surfaces Ta are inclined toward each other, and face the surface of the workpiece W.

<Effects of this embodiment>
According to the sputtering apparatus 100 of this embodiment configured in this manner, the sputtering surface Ta of the target T extends obliquely toward the opposite side of the antenna 5 relative to the dielectric plate 6, so that the high-frequency magnetic field extending from the antenna 5 can be efficiently guided to the sputtering surface Ta.
As a result, in a configuration in which the antenna 5 is provided outside the vacuum vessel 1, the distance to the workpiece W can be shortened, thereby enabling the target T to be sputtered efficiently while improving the film formation speed and processing efficiency.
Furthermore, by inclining the sputtering surface Ta, the spread of sputtered particles onto the workpiece W can be suppressed, and the utilization rate of the sputtering source can be increased.

In addition, targets T are held on both sides of the dielectric plate 6, which further improves the film formation speed and processing efficiency.

<Other Modified Embodiments>
The present invention is not limited to the above-described embodiment.

For example, in the above embodiment, targets T were provided at both positions where the dielectric plate 6 is sandwiched, but targets T may be provided at only one of the positions where the dielectric plate 6 is sandwiched.

In addition, the sputtering device 100 in the above embodiment is equipped with one antenna 5 and a pair of targets T, but it may be equipped with multiple antennas 5 arranged in parallel to each other, or multiple pairs of targets T corresponding to these antennas 5.

Furthermore, in the above embodiment, the magnetic field transmission window was formed by the dielectric plate 6, but as shown in Figure 3, the magnetic field transmission window may be formed by placing the dielectric plate 6 on a slit plate 11 having a plurality of slits 11s formed therein, and the slit plate 11 and the dielectric plate 6 may form a magnetic field transmission window.
In this configuration, the magnetic field transmission window is formed by overlapping the slit plate 11 and the dielectric plate 6, so that the thickness of the magnetic field transmission window can be made smaller than when the magnetic field transmission window is performed only by the dielectric plate 6. This makes it possible to shorten the distance from the antenna 5 to the inside of the vacuum vessel 1, and to efficiently supply the high frequency magnetic field generated by the antenna 5 into the vacuum vessel 1.

In addition, the sputtering apparatus 100 may be equipped with a moving mechanism for transporting the workpiece W into the vacuum vessel 1 or for swinging the workpiece W within the vacuum vessel 1.

In addition, the sputtering apparatus 100 may be, for example, a cylindrical vacuum vessel 1 as shown in FIG. 4, and may include a moving mechanism 12 that rotates and moves the workpiece W being processed around an axis parallel to the axial direction of the vacuum vessel 1.
With such a configuration, the workpiece W can be, for example, a tool, and by forming a film on the surface of the tool, etc., it is possible to improve the tool's lifespan, etc.

It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the invention.

Reference Signs List 100: sputtering device W: workpiece T: target Ta: sputtering surface 1: vacuum vessel 3: target holder 5: antenna 6: dielectric plate θ: inclination angle S: slit 11: slit plate

Claims (3)

A sputtering apparatus that sputters a target using plasma to form a film on a workpiece, comprising:
a vacuum vessel that is evacuated;
an antenna provided outside the vacuum vessel;
a dielectric plate provided on an outer wall of the vacuum vessel at a position facing the antenna;
a target holder that holds the target in the vacuum vessel;
a workpiece holder that holds the workpiece in the vacuum chamber so as to face the dielectric plate ,
the dielectric plate is formed along a direction perpendicular to a direction in which the antenna and the workpiece face each other,
the target is disposed between the dielectric plate and the workpiece in the facing direction, and is provided at one or both of the positions sandwiching the dielectric plate in the orthogonal direction , the sputtering surface of the target extends obliquely toward the opposite side to the antenna with respect to the dielectric plate, and is inclined so as to approach the workpiece in the facing direction as it moves away from the dielectric plate in the orthogonal direction ,
A sputtering apparatus, wherein an inclination angle of the sputtering surface of the target with respect to the dielectric plate is 10 degrees or more and 45 degrees or less . The sputtering device according to claim 1, wherein the targets are provided at both positions that sandwich the dielectric plate, and the sputtering surfaces of the targets each extend obliquely toward the opposite side of the antenna relative to the dielectric plate. 3. The sputtering apparatus according to claim 1, wherein the dielectric plate is placed on a slit plate having a plurality of slits formed therein.