JPH05311430A - Magnetron sputtering cathode - Google Patents

Abstract

PURPOSE:To enable the rapid exchange of a consumed magnetic material target and to improve the operating rate of a device by generating a reverse magnetic field and weakening the attraction force of permanent magnets at the time of exchanging the target. CONSTITUTION:A first magnetic pole is constituted of the columnar permanent magnet 1 and a magnetic pole 3 of a columnar soft magnetic material and a second magnetic pole is constituted of the cylindrical permanent magnet 2 and a magnetic pole 4 of a cylindrical soft magnetic material. The magnetic material target 9 is provided via a backing plate 8 made of copper having a groove 8c and is cooled via the groove 8c. Sputtering is executed by maintaining the magnetron sputtering discharge on the front surface side of the target only by the magnetic field generated by the permanent magnets 1, 2. The operation of a cooling system is stopped and reverse magnetic coils 5, 6, 7 are energized to generate the reverse magnetic fields below the coercive force of the permanent magnets 1, 2 and to weaken the attraction force of the permanent magnets 1, 2 at the time of exchanging the consumed target 9. The target 9 is then removed together with a backing plate 8 and thereafter, the currents of the reverse magnetic coils 5, 6, 7 are turned off. The target 9 is, therefore, removable in a short period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering cathode, which is a component of a sputtering apparatus used for manufacturing semiconductors, and more specifically, a flat plate-shaped magnetic substance target on which plasma is generated on the front side, and the target of the target. A first magnetic pole disposed on the back side of the central portion, the magnetization direction of which is perpendicular to the surface of the target; and a second magnetic pole which surrounds the first magnetic pole and has a magnetization direction opposite to the first magnetic pole, The present invention relates to a structure of a magnetron sputtering cathode, which comprises a backing plate which is arranged on the magnetic target side of the first and second magnetic poles and whose targets are fixed by abutting their back surfaces.

[0002]

2. Description of the Related Art FIG. 2 shows a schematic diagram of a conventionally used magnetron sputtering cathode (hereinafter referred to as a cathode or magnetron cathode) having a flat magnetic target. The cathode is a magnetic target 9 in which plasma is generated on the front side (upper side in the figure).
A columnar first magnetic pole 14 arranged on the rear side of the center of the target 9 in the direction perpendicular to the plate surface of the target; a second cylindrical magnetic pole 15 surrounding the first magnetic pole 14; A plate-shaped yoke 16 forming a magnetic path between the lower end surfaces of the second magnetic pole, a first coil 17 surrounding the first magnetic pole 14, and a second magnetic pole 15
Is arranged along the inner side of the second pole in the opposite direction to the first magnetic pole 14.
The second coil 18 that magnetizes the magnetic pole 15 of the second magnetic pole, and the second magnetic pole that surrounds the second magnetic pole 15 from the outside in the same direction as the second coil 18.
Third coil 19 for magnetizing 15 and first and second magnetic poles
Central columnar first backing plate magnetic poles 11 and 1 having lower end surfaces respectively contacting upper end surfaces 14 and 15
A second backing plate magnetic pole 12 surrounding the backing plate 11 and first and second backing plate magnetic poles 11, 12
And a backing plate 13 made of non-magnetic metal, which is integrated with the magnetic target 9 and is adhered and fixed to the upper surface of the backing plate 13. Further, the cooling water circulates inside the cathode by a circulation mechanism (not shown), and the temperature rise of the target 9 due to the ion irradiation from the plasma,
It functions to suppress the temperature rise of the coils due to the current flowing through the first and second coils 17 and 18.

In the sputtering film formation on the sample by the magnetron sputtering apparatus having the cathode thus constructed, the magnetic target 9 is formed in a predetermined gas pressure atmosphere.
A voltage having a positive polarity against the target is applied to the sample or the flat plate electrode located on the back side of the sample, and a current is passed through the first, second, and third coils 17, 18, 19 to target the magnetic material. An annular magnetic field of a predetermined strength is formed on the front side of 9 to form a thin plasma space called an ion sheath just before the magnetic material target 9 and the ions in the plasma are accelerated by the electric field strength of this space. Then, the atoms or molecules are knocked out from the magnetic material target 9 and attached to the sample. Cooling water is of course circulated during film formation. When replacing the target 9 after it has been cut to a specified thickness or more, stop the coil power supply, discharge power supply, cooling water, forcibly discharge the water remaining inside the cathode by air etc., and then remove the target 9 together with the backing plate 13. Is common.

[0004]

However, the cathode has the following problems. First, in order to cool both the target and the coil, the entire first pole is
In addition, the inner surface of the second magnetic pole comes into contact with water, the cooling system is clogged due to rust, and the magnetic field distribution on the front side of the target changes due to rust adhering to the abutting surface of each magnetic pole and backing plate Is likely to occur. Secondly, the coil
Since the first and second coils are submerged in water, the coils and the terminals are required to be more waterproof than usual for electrical insulation. Thirdly, when the target is replaced, the surrounding members are contaminated with water, and the water remaining in the cathode cannot be completely removed, and the water remains inside the cathode. Therefore, it takes time to start up the device after the replacement. It takes.

An object of the present invention is to provide, as a magnetron cathode having the structure described at the beginning, a structure of the cathode which solves the problems caused by the cooling water and does not require a lot of time to start up the apparatus. Is.

[0006]

In order to solve the above-mentioned problems, in the present invention, a magnetron cathode having the structure intended by the present invention, that is, a flat plate-shaped magnetic substance target on which plasma is generated on the front side is provided. A first magnetic pole having a magnetization direction perpendicular to the surface of the target and a second magnetic pole surrounding the first magnetic pole and having a magnetization direction opposite to the first magnetic pole, And a backing plate which is disposed on the magnetic target side of the first and second magnetic poles and which is fixed by bringing the targets into contact with the back surfaces of the magnetron sputtering cathodes. At least a part of the cathode includes a permanent magnet in series and a backing plate is a cathode formed so that the target can be cooled.

According to the concrete structure based on this basic structure, the first and second magnetic poles including a permanent magnet in series at least in a part thereof respectively connect the permanent magnet and the soft magnetic material magnetic pole in series. The soft magnetic material magnetic poles are positioned so as to be separably contacted with each other, and each soft magnetic material magnetic pole is located on the target side. It is extremely suitable to have such a configuration.

The backing plate formed so that the target can be cooled is preferably formed so that the refrigerant can flow through the inside thereof.

[0009]

When the magnetron cathode is constructed as described above, the coil for forming the annular magnetic field on the front side of the magnetic material target is not required, so that cooling of the coil is not required and the backing plate itself is made of the magnetic material. Since it will have the cooling function of the target, the coil and magnetic pole will not be immersed in water or come into contact with water as in the conventional case, so that clogging of the cooling system and contamination of peripheral members due to rust will not occur. In addition, water is not left in the cathode after the target is replaced, and the device starts up quickly.

Therefore, based on the above-mentioned basic structure of the magnetron cathode, the first and second magnetic poles are formed by respectively contacting the permanent magnet and the magnetic pole of the soft magnetic material in series and in a separable manner, and If all magnetic material magnetic poles are located on the target side and a solenoid coil for magnetizing the soft magnetic material magnetic poles in the opposite direction to the permanent magnets in series is added to each soft magnetic material magnetic pole, the solenoid coil will be replaced when the target is replaced. The target can be replaced very easily by exciting the magnet to weaken the attractive force of the permanent magnet to the target, and since the energization time to the solenoid coil at this time is short, it is necessary to cool the coil. In addition, the above-mentioned problems do not occur again.

In addition, the backing plate formed so that the target can be cooled can allow the refrigerant to flow through it.
By forming a cavity or a flow channel in the interior so as to send the refrigerant into the cavity or the flow channel, the target can be cooled without complicating the cooling system including the backing plate.

[0012]

FIG. 1 shows an embodiment of the magnetron cathode structure according to the present invention. The first magnetic pole is a columnar permanent magnet 1
And a columnar soft magnetic material magnetic pole 3 which is in contact with and separated from the end face of the columnar permanent magnet 1 on the target 9 side, and the second magnetic pole is a cylindrical permanent magnet 2 and the cylinder. The permanent magnet 2 has a cylindrical soft magnetic material magnetic pole 4 abutting on the end surface of the permanent magnet 2 on the target 9 side so as to be separable. A backing plate 8 made of a non-magnetic metal, here a copper material, is adhered and fixed to the upper end surfaces of the soft magnetic material magnetic poles 3 and 4, and the soft magnetic material magnetic poles 3 and 4 are integrated via the backing plate 8. To be done. The backing plate 8 is one thick plate 8a.
And another thin plate 8b, a thick plate 8a has a groove 8c formed in one surface thereof to form a flow path for the refrigerant, and the upper surface side of the flow path is closed by the thin plate 8b. Although the flow path pattern can be various, the target 9 is formed so as to be cooled to a uniform temperature during the sputtering. Cooling water as a refrigerant sent from the outside to this flow path is circulated in a circulation path including the backing plate 8 by a circulation pump 21 which constitutes a cooling system, and is cooled by a cooler 22 in the middle of circulation.

Sputtering by the magnetron cathode thus constructed is carried out as follows. During sputtering, no current is applied to the reverse excitation solenoid coils (hereinafter also referred to as reverse magnetic coils) 5, 6 and 7, and the magnetron discharge on the front side of the target is maintained only by the magnetic fields generated by the permanent magnets 1 and 2. Cooling water circulates in the backing plate 8 to cool the target 9.

When the target 9 is consumed more than a predetermined depth due to sputtering and the target is replaced, the cooling system is stopped and the reverse magnet coils 5, 6 and 7 are energized to hold the permanent magnet. Generate the following reverse magnetic field,
The attracting force of the permanent magnet is weakened and the target 9 is removed together with the backing plate 8, and then the currents of the reverse magnetic coils 5, 6, 7 are cut off. Usually, the coil current for canceling the holding force of the permanent magnet is considerably large, but the energization time is short while the target is removed, so that it is not necessary to circulate cooling water to cool the coil.

[0015]

As described above, according to the present invention, the magnetron cathode having the structure described at the beginning, that is, the flat plate-like magnetic target on which plasma is generated on the front side, and the rear side of the central portion of the target is formed. Placed On,
A first magnetic pole whose magnetization direction is perpendicular to the surface of the target, a second magnetic pole that surrounds the first magnetic pole and has a magnetization direction opposite to the first magnetic pole, and magnetism of the first and second magnetic poles. A magnetron sputtering cathode having a backing plate disposed on the side of the body target and fixed with the back surface abutting against the back side; and a backing with the first and second magnetic poles including permanent magnets in series at least at a part thereof. As the plate is formed so that the target can be cooled, the permanent magnet is used to form the annular magnetic field on the front side of the target even in the case of the magnetic target, so the coil required when the permanent magnet is not used. No cooling is required, and no rust occurs when the cooling water comes into contact with the magnetic poles, preventing contamination of surrounding materials and replacing the target. No water remaining in the cathode internally, reduces the startup time of the apparatus after Tagetsuto replacement, improved operation rate of the apparatus. Further, the cooling during sputtering may be performed only by the target, and the cooling function is also given to the backing plate, so that the structure of the cathode is simplified.

The first and second magnetic poles are formed by contacting a permanent magnet and a soft magnetic material magnetic pole in series so that they can come into contact with and separate from each other, and both the soft magnetic material magnetic poles are on the target side. By locating and adding a solenoid coil to each soft magnetic material magnetic pole to magnetize the soft magnetic material magnetic pole in the direction opposite to that of the permanent magnet in series, the target can be easily removed from the permanent magnet simply by exciting the solenoid coil when replacing the target. It is possible to separate it and it becomes easy to replace it.

Further, since the target cooling function of the backing plate is provided by configuring the backing plate so that the refrigerant flows through the inside of the backing plate, the structure of the backing plate and the configuration of the cooling system are complicated. The target can be cooled without doing so, and the need for the first and second magnetic pole coils is eliminated,
There is an advantage that the cooling system is inexpensive.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a magnetron cathode configuration according to the present invention.

FIG. 2 is a schematic configuration diagram showing an example of a conventional magnetron cathode configuration.

[Explanation of symbols]

 1 permanent magnet 2 permanent magnet 3 soft magnetic material magnetic pole 4 soft magnetic material magnetic pole 5 reverse magnetic coil 6 reverse magnetic coil 7 reverse magnetic coil 8 backing plate 9 magnetic material target

Claims (3)

[Claims] 1. A flat plate-shaped magnetic target, on the front side of which plasma is generated, a first magnetic pole, which is arranged on the rear side of the center of the target, and has a magnetization direction perpendicular to the surface of the target. A second magnetic pole, which surrounds the first magnetic pole and has a magnetization direction opposite to the first magnetic pole, is arranged on the magnetic target sides of the first and second magnetic poles, and the targets are fixed with their back surfaces in contact. A magnetron sputtering cathode comprising a backing plate, wherein the first and second magnetic poles include a permanent magnet in series at least in a part thereof and the backing plate is formed so as to cool the target. Sputtering cathode. 2. The magnetron sputtering cathode according to claim 1, wherein the first and second magnetic poles each including a permanent magnet in series in at least a part thereof are respectively
The permanent magnet and the soft magnetic material magnetic pole are contacted in series so that they can be contacted and separated from each other, and the soft magnetic material magnetic poles are all located on the target side. A magnetron sputtering cathode characterized in that an inverse magnetic coil for magnetizing a magnetic pole of a soft magnetic material is added. 3. The magnetron sputtering cathode according to claim 1, wherein the backing plate formed so that the target can be cooled is formed so that a refrigerant can flow through the inside thereof.