JPH0639690B2 - Sputtering equipment - Google Patents

Description

The present invention relates to a sputtering apparatus.

(Prior Art) As a device for forming a refractory metal or an alloy film of a silicide of this refractory metal on a substrate to be processed, for example, a semiconductor wafer, generally, an atmosphere of a pressure of about 10 ^-3 to 10 ^-2 Torr is used. An apparatus is used in which a voltage is applied between two electrodes in an argon (Ar) gas to generate an argon plasma, and a target is sputtered by the argon plasma to deposit an alloy film on a semiconductor wafer.

Regarding the above-mentioned sputtering, see, for example,
57-149470 and JP-A-58-136776.

(Problems to be solved by the invention) However, in the above-mentioned disclosed, when a target composed of, for example, tungsten silicide (W Si) is used as a target, sputtered particles, particularly silicon (Si) particles, are generated between the electrodes. There is a possibility that they may be deposited in the gap and cause insulation failure between the electrodes, or that deposits that have adhered to the target other than the sputtering surface may peel off and cause abnormal discharge.

The present invention has been made in consideration of the above-mentioned conventional circumstances, and an object thereof is to provide a sputtering apparatus of high quality and high stability, which is free from insulation failure and abnormal discharge.

(Means for Solving the Problems) The present invention is a sputtering apparatus that performs sputtering by generating plasma in a processing chamber, a cathode provided with a target, an anode arranged in proximity to the cathode, and the cathode. And a gas flow path provided between the anode and the gas flow path, and a gas supply means for supplying at least a gas during sputtering to the gas flow path.

(Operation) In the present invention, the gas is introduced from the gas flow path provided in the gap between the cathode and the anode, so that the sputtered particles can be repelled by the flow of the gas particles.

Therefore, it is possible to prevent the sputtered particles from being deposited in the middle of the first electrode and the second electrode.

(Example) Hereinafter, one example of the sputtering apparatus of the present invention will be described with reference to the drawings.

A sputter gun portion (2) formed in a cylindrical shape, for example, is hermetically attached to the bottom of the processing chamber (1) by welding or other means.

The lower part of this sputter gun section (2) is
Excitation coil wound in an annular shape around the center of (2)
(3) is built in, and this exciting coil (3) is connected to the exciting coil power supply (4).

Next, an annular groove (5) is formed in the upper part of the sputter gun part (2) , and the outer part and inner part of the groove (5) are respectively formed by the magnetic field generated by the exciting coil (3).
(6) It is made of a magnetic material so as to act as the inner magnetic pole (7) and also as the first electrode (8) for plasma generation.

In addition, in the groove (5), the second electrode (10) for plasma generation, which is annularly formed and has the target (9) for supporting the material to be sputtered, is insulated from the first electrode (8). And a gas flow passage having a width of about 1.5 to 3.0 mm, that is, a gas inlet port (11) between the first electrode (8) and the second electrode (10).
Is configured to be formed in an annular shape.

The first electrode (8) and the second electrode (10) are the processing chamber (1)
It is connected to a sputtering power source (12) provided outside.

Next, a large number of small holes (13) are provided near the bottom of the groove (5), and these small holes (13) are used for gas introduction source (14) provided outside the processing chamber (1). Collective communication is established by a gas introduction pipe (16) through an introduction valve (15). Then, the gas introduction source (1
An inert gas such as argon or helium can be introduced from 4) toward the processing chamber (1) through the gas inlet (11).

On the other hand, a heating mechanism (not shown) is provided in the upper portion of the processing chamber (1), and has a disk shape so as to hold a substrate to be processed, for example, a semiconductor wafer (17) facing the sputter gun unit (2) side. Susceptor
(18) is suspended.

Further, a vacuum pump (19) for depressurizing the inside of the processing chamber (1) to a predetermined pressure through the side wall of the processing chamber (1), and a vacuum gauge (20) for displaying the degree of vacuum in the processing chamber (1). ), A main gas introduction source (21) for introducing a gas generating plasma such as argon (Ar) gas into the processing chamber (1) is connected.

Next, the operation will be described.

First, the semiconductor wafer (17) is transferred by a transfer mechanism (not shown) or the like.
Is carried into the processing chamber (1), and the semiconductor wafer (17) is held by the susceptor (18). Next, the vacuum pump (19) is operated to evacuate and the semiconductor wafer (17) is heated to a predetermined temperature. Next, argon gas is introduced from the main gas introduction source (21), and the inside of the processing chamber (1) is kept in a reduced pressure state so that the vacuum gauge (20) displays about 10 ⁻³ to 10 ⁻² Torr.

Then, a current is applied to the exciting coil (3) by the exciting coil power source (4) to magnetize the sputter gun section (2).
The (7) is magnetized so as to be the N pole and the outer magnetic pole (6) is the S pole.

In addition, for example, the first electrode (8) is supplied by the sputtering power source (12).
Is used as an anode and the second electrode (10) provided with the target (9) is used as a cathode, and a DC voltage of about 0.5 to 1 KV is applied to generate a plasma discharge to cause an argon plasma (22) on the upper surface of the target (9). Generate. At the same time, the gas introduction valve (15) is opened to introduce a gas from the gas introduction source (14), for example, argon gas, and the gas inlet port is provided through the gas introduction pipe (16).
From (11), flow into the chamber (1) at a flow rate of about several tens SCCM (SCCM is a flow rate CC per minute under standard conditions).

At this time, as shown in FIG. 2, the outer magnetic pole (6) and the inner magnetic pole are
Target (9) by magnetic field lines (23) formed by (7)
The argon ions (24) of the argon plasma (22) trapped near the top surface collide with the target (9),
From (9) refractory metal or silicide of this refractory metal,
For example, if the target (9) is tungsten silicide (WS
When it is composed of i), tungsten atoms (25), silicon atoms (26), etc. are knocked out as sputtered particles.

The knocked out tungsten atoms (25) are replaced by argon atoms (2
Although it scatters in the chamber (1) where 7) exists, when the tungsten atom (25) and the argon atom (27) collide,
Since the mass of tungsten atom (25) is larger than that of argon atom (27), tungsten atom (25) is an argon atom.
(27) is blown away to proceed and adhere to the semiconductor wafer (17) to form a tungsten film.

On the other hand, since the silicon atom (26) has a smaller mass than the argon atom (27), the silicon atom (26) and the argon atom (27)
In case of collision, silicon atom (26) becomes argon atom (27)
It is thrown away by the target and is not scattered toward the inside of the chamber (1), but around the target (9), that is, in the gap near the middle of the first electrode (8) and the second electrode (10). Deposition and deposition.

Therefore, if the silicon atoms (26) adhere and accumulate in the gap near the middle of the first electrode (8) and the second electrode (10), insulation failure between the electrodes may occur or peeling may occur. If the target material (9) adheres to the target (9), abnormal discharge occurs and the target (9) is largely sputtered locally, and the agglomerated target material (9) becomes foreign matter as a semiconductor wafer (17).
May adhere to.

Therefore, a gas inlet (11) is provided between the first electrode (8) and the second electrode (10) so that the silicon atom (26) or the like is blown away at all times or at least during sputtering. In the chamber, for example, several tens SCCM of argon gas is used.
When it flows into (1), sputtered particles such as the silicon atoms (26) can be repelled. Therefore,
As described above, the silicon atoms (26) do not deposit and accumulate as described above, and it is possible to prevent the occurrence of insulation failure and abnormal discharge.

In the above embodiment, an example of forming a tungsten film has been described, but the present invention changes the material of the target (9) to form a film such as WSi, Mo, Ta, TaSi, Ti, TiSi. It goes without saying that it can also be applied when doing.

Further, in the above embodiment, the case of DC sputtering was explained, but it is also applicable to magnetron sputtering, high frequency sputtering and the like.

Further, the gas inflow from the gas inflow port (11) may be always or at least during the sputtering.

〔The invention's effect〕

As described above, according to the present invention, the sputtered particles deposited in the gap between the cathode and the anode can be repelled, and the defective insulation and the abnormal discharge between the adjacent cathode and anode can be prevented.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining one embodiment of the sputtering method of the present invention, and FIG. 2 is an explanatory diagram of the main part of FIG. 1 ... Processing chamber, 2 ... Sputter gun part, 3 ... Excitation coil, 6 ... Outer magnetic pole, 7 ... Inner magnetic pole, 8 ... First electrode, 9 ... Target, 10 ... Second Electrode, 11 ... Gas inlet, 14 ... Gas inlet, 17 ... Semiconductor wafer, 22 ... Argon plasma, 23 ... Magnetic field line, 25 ... Tungsten atom, 26 ... Silicon atom, 27 ... Argon atom .

Claims (1)

[Claims] 1. A sputtering apparatus for generating plasma in a processing chamber to perform sputtering, a cathode provided with a target, an anode arranged in proximity to the cathode, and provided between the cathode and the anode. A sputtering apparatus comprising a gas flow path and a gas supply means for supplying at least a gas during sputtering to the gas flow path.