JPS62287073A - Cathode device for magnetron sputtering - Google Patents

Abstract

PURPOSE:To inhibit rise of temp. of a substrate by placing a prescribed electron capturing shield so as to capture electrons emitted from the central part of a target toward the substrate and to reduce the amount of electrons flowing into the substrate. CONSTITUTION:This cathode device for magnetron sputtering is composed essentially of a flat plate-shaped cathode 11 acting as a target, magnets 12a, 12b arranged at the central part of the cathode and along the peripheral part and an electron capturing shield 20. This shield 20 is placed opposite to the central magnet 12a with the cathode 11 in-between and is supported mechanically and electrically by a bent support part on the outside of an earth electrode 30.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a cathode device used in magnetron sputtering, and more specifically to a cathode device used for magnetron sputtering. This relates to how to install the shield.

[Summary of the invention]

The present invention provides a cathode device consisting of a flat cathode serving as a target and a magnet placed at the center and outer periphery of the cathode. By arranging an electron capture shield that is mechanically and electrically supported on the outer circumferential side of the cathode by a curved support part at a position where it This is to realize the following.

[Conventional technology]

Magnetron sputtering is known as a low-temperature, high-speed deposition method compared to Goiot sputtering, etc.
Generally, a magnetron spankling device equipped with a planar type (flat plate type) cathode device is used. This planar type sputtering apparatus has great practical advantages because the electrode arrangement is the same as that of DC bipolar, high frequency, etc. apparatuses, and a flat electrode can be used as the cathode.

However, even with this magnetron sputtering, it has been pointed out that in a sputtering apparatus equipped with the above-mentioned planar type cathode device, the substrate is considerably heated due to the electron impact on the substrate. Heating of this substrate has a great effect on the properties of the obtained thin film. For example, when the substrate is heated when producing a two-layer perpendicular magnetic recording medium, the permalloy film, which is an in-plane magnetization layer, and the perpendicular anisotropy layer of Co
- This is not preferable because the magnetic properties of the Cr film are deteriorated and a curved deformation called curl occurs.

Other problems also arise when forming a somewhat thick film by sputtering or when depositing a material that easily reacts when heated.

In order to improve this problem, an incident-type cathode device has been proposed in which an electron capture shield is provided at the center of a ring-shaped target.

[Problem that the invention seeks to solve]

However, the above-mentioned insent-type cathode device
Although the temperature rise can be reduced, the structure of the target is donut-shaped and an electron capture shield is provided in the center. ■) The target structure is more complex than a planar cathode device, making it difficult to manufacture the target and its surrounding equipment. 2) After sputtering, cleaning work or target replacement work becomes complicated.

The present invention was proposed in view of the above circumstances, and it is possible to easily install an electron capture shield without changing the target of a planar type cathode device with a simple structure, thereby reducing the rise in substrate temperature. The purpose is to provide fewer cathode devices.

[Means for solving problems]

In order to achieve the above object, the cathode device for magnetron sputtering of the present invention includes a flat cathode serving as a target, a magnet placed at the center and outer periphery of this cathode, and a magnet placed at the center. It consists of a magnet and an electron capture shield disposed opposite to each other across the cathode, and the electron capture shield is mechanically and electrically supported on the cathode outer peripheral side by a curved support part. It is said that

[Effect]

When the cathode device of the present invention is used, electrons that fly out from the center of the target toward the substrate due to the direction of the magnetic field at the center of the target, which is the cathode, are captured by the electron capture shield.

Therefore, the amount of electrons flowing into the substrate is greatly reduced, and the rise in temperature of the substrate is suppressed.

On the other hand, the discharge plasma on the cathode is confined around the donut-shaped magnetic field tunnel of the magnet arranged at the center and outer periphery of the cathode. Here, the support portion of the electron capture shield is curved to avoid the donut-shaped discharge plasma, so the support portion does not cross the discharge plasma. Therefore, sputtering efficiency does not decrease.

〔Example〕

The present invention will be explained below based on specific examples.
It goes without saying that the present invention is not limited to this embodiment.

A continuous magnetron sputtering device that continuously sputters a long substrate film has a can roll (
2), an unwinding roll (3), a means for continuously moving the substrate film (5) such as a take-up roll (4), a mask (6) having a predetermined opening angle, and further a target (11),
Cathode (10) composed of magnet (12) etc.
The substrate film (5) such as a polymer film supplied from the unwinding roll (3) is transferred to the can roll (2).
) while moving in the direction of the arrow X, sputter atoms from the cathode (10) connected to the sputtering power source, that is, the target (11), are deposited through the mask (6) to form a thin film. and is configured to be wound onto a take-up roll (4).

In a planar type magnetron sputtering device, the cathode (1o) is a flat target (11
) (It is installed as a cathode, and during sputtering, constituent atoms are knocked out by argon ions and becomes an evaporation source.), a magnet (12) for restraining high-density discharge plasma on the target (11), and the magnet ( 12) and a yoke (13) to secure a magnetic path on the bank side, so that ions created near the target (11) efficiently collide with the target (11) to cause sputtering. There is.

Here, the magnet (12) is the target (11)
A cylindrical magnet (1, 2a) placed in the center of
and a ring-shaped magnet (12b) arranged along the outer periphery of the target saw 1-(11,), and the magnetic poles are arranged such that the north pole is at the center and the south pole is at the outer periphery. Therefore, the above magneso) (12a), (1
The magnetic field lines due to 2b) are closed as shown by the dashed line M in the first leap, and a toroidal type day
- Nara type) magnetic field tunnel is created, and the discharge plasma is almost confined around this L/N-F. However, the magnet y placed at the center of the target (1) above
) In the center of (12a), the direction of the magnetic field lines is perpendicular to the target plane (11) toward the substrate film (5), and the electrons generated by the discharge collide with the substrate film (5), causing heating. It becomes every.

Therefore, in the present invention, an electron capture shield (20) is mounted on the target (11) to collect electrons without flying out from the center.

As shown in FIGS. 2 and 3, the electron capture seal F (20) has an elliptical shielding portion ( 21) and a ring-shaped attachment part (22) to be attached to the shielding part (11).
21) is a pair of curved, substantially arc-shaped support portions (23).
), (23) mechanically and electrically connect the attachment part (2
2) is connected and supported. Here, "two-part support part (2
The reason why the support part (23) is curved into a substantially arc shape is to avoid the discharge plasma being restrained in the tunnel of the I-roidal type magnetic field. It does not cross the discharge plasma, and there is no possibility of affecting the generated discharge plasma. The shape of the support portion (23) is not limited to the above-mentioned arc shape, but may be any shape as long as it can avoid discharge plasma.

In addition, the external dimensions of the mounting portion (22) are as follows:
(11), and a claw portion (22a) is provided at the center of each side on the lower side [target (11)].
) in the mounting direction).

Therefore, the electron capture shield (2o) is easily attached to the cathode (10) by locking the claw part (22a) of the attachment part (22) to the target (11).

By attaching the electron capture shield (20) having such a structure, the flow of electrons flying out from the center of the target film (11) toward the substrate film (5) can be controlled by the shielding part (20).
1), and the supporting part (23) and the mounting part (22
) through which the cathode is quickly targeted (1-(1,1)
be led to. As a result, the flow of electrons that cause heat generation in the substrate is removed, and the substrate film (5) is not heated.

Next, an explanation will be given based on experimental results by the present inventors.

First, a Mo-permalloy film was exploded using the continuous Magne-I Ron spackling device shown in FIG. The sputtering conditions are as follows.

λet Tsuttering condition target MO-permalloy (Ni 80.5X, Fe 15X, Mo 4.5
X) 15 (inX 250mm x 15mm Substrate Polyethylene terecrate film (thickness 50μm) Argon pressure I X 10-3Torr input power
1 kW Can roll temperature 40゛c Substrate-target distance 65
5) A thermocouple (14) installed nearby was used to investigate the temperature rise during sputtering depending on the presence or absence of an electron capture shield. The results are shown in Figure 4. Note that the same applies to the following drawings, but in the drawings, the curve a shows the case where the electron capture shield (20) is provided, and the curve a shows the case where the electron capture shield (20) is not provided.

As is clear from this Figure 4, the electron capture shield (2
0) has a large temperature rise suppressing effect. In addition, the self-bias voltage of the board when power is applied to -1 kW is -4,0 when the electron capture shield (20) is installed.
As can be seen from the fact that V is -18.4 V when not installed, the flow of electrons to the substrate film (5) is small.Then, the film formation efficiency for the same input power under this condition is The reduction was approximately 5%, making the reduction in sputter deposition rate virtually negligible.

Next, using the same equipment, the equilibrium temperature for the input power,
In addition, the current-voltage characteristics were investigated. Note that the conditions other than the input power were the same as the previous sputtering conditions. The results are shown in FIGS. 5 and 6.

From Figure 5, we can see that the electron capture shield (2
0) temperature suppression effect was confirmed.

On the other hand, as shown in Figure 6, an electron capture shield (20
), an increase in impedance can be seen, but
Impedance increase for the same current is 15-18%
It was not large enough to be a problem.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, there is no need to make the target into a special shape, and an electron capture shield for suppressing the temperature rise of the substrate can be easily added to the conventional planar target. can be installed. Therefore, it is possible to provide a cathode device in which a thin film with excellent properties can be produced without any adverse effects caused by a rise in temperature of the substrate.

Further, the cathode device of the present invention has an extremely simple structure, and in particular, the electron capture shield can be easily attached and removed, so that cleaning and target replacement after sputtering are easily performed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration example of a continuous magnetron sputtering device using the cathode device of the present invention, and FIG. 2 is an external view showing an example of an electron capture shield attached to the cathode device of the present invention. The perspective view and FIG. 3 are cross-sectional views taken along the line AA in FIG. 2. Figure 4 is a characteristic diagram that compares the temperature rise due to sputtering with and without an electron capture shield, and Figure 5 shows input power and equilibrium temperature when an electron capture shield is attached. FIG. 6 is a characteristic diagram showing the difference in current-voltage characteristics depending on the presence or absence of an electron capture shield. 10... Cathode 11... Target (cathode) 12'... Magnet 20... Electron capture shield 21... Shielding part 22... Mounting part 23... Supporting part

Claims (1)

[Scope of Claims] A flat cathode serving as a target, a magnet disposed at the center and outer periphery of the cathode, and a magnet disposed at a position facing the magnet disposed at the center with the cathode in between. A cathode device for magnetron sputtering, characterized in that the electron capture shield is mechanically and electrically supported on the cathode outer peripheral side by a curved support portion.