JPH0222145B2 - - Google Patents

Description

[Detailed Description of the Invention] Conventionally, in a sputtering device for forming a thin film,
Depending on the film formation conditions, a high vacuum atmosphere or the use of conventional electrodes may be required.
For this reason, problems such as high discharge impedance between the electrode and the wall of the vacuum vessel (earth potential) can cause problems with discharge, or low current density can cause the discharge to become unstable and often stop. was occurring.

Conventionally, the following solutions (1), (2), and (3) have been used to solve this problem.
The following methods have been adopted.

That is, (1) a discharge trigger electrode is provided separately from the sputter electrode, and a discharge trigger voltage is applied to this electrode. (2)
A thermal filament is placed in a vacuum to generate thermoelectrons, which trigger a discharge. (3) Temporarily supply argon gas or the like into the vacuum container to temporarily increase the gas pressure inside the container to facilitate the initiation of discharge, and after discharge, gradually return the vacuum pressure to the original film forming conditions.

These may be used in combination.

However, these conventional methods have the following drawbacks.

That is, in methods (1) and (2), it is necessary to install a port for the trigger electrode in the vacuum separately from the sputter electrode, and when the discharge stops, the stop of the discharge current is detected and the trigger is automatically triggered. It is necessary to install complex equipment that can apply Since (3) temporarily worsens the vacuum pressure, there is a loss time between the start of discharge and the time when the pressure returns to the required film-forming conditions, and if the discharge stops frequently, the film-forming conditions may be affected. It has the disadvantage of causing changes in conditions.

The scheme of the present invention overcomes these drawbacks.

The present invention will be explained below with reference to Examples.

In FIG. 1, power is supplied to the electrode 7 from the main power source 2 exclusively for sputtering through a diode 4, but this electrode 7 is supplied with a voltage higher than the power source 2 exclusively for sputtering through a high resistance 5 and a diode 3 in parallel with the above. A trigger power source 1 having a voltage slightly higher than the discharge starting voltage of the electrode 7 is provided. When installed in this way, a voltage approximately equal to the voltage of the power supply 2 is applied to the electrode 7 during normal sputter discharge, but a large voltage is applied between the trigger voltage source 1 and the electrode 7 due to the resistor 5. It causes a voltage drop and is in equilibrium in that state.

Now, when this normal sputter discharge stops for some reason, the potential of the electrode 7 instantly rises to the potential of the power source 1. Therefore, the discharge is immediately triggered by the high voltage. The discharge subsequently returns to its original equilibrium state. Therefore, normal and stable discharge can be continued without any problem.

The above describes the case of stopping the discharge during normal discharge, but the same applies when starting the discharge, and the above process is automatically carried out until a normal discharge state is reached.

FIG. 2 shows another embodiment of the present invention, in which a high frequency power source is used as the main dedicated sputtering power source 2 of the sputtering device. The difference from Fig. 1 is to prevent the power sent from this high frequency power supply 2 from flowing into the trigger power supply installed in the present invention, and also to prevent this power from leaking through the trigger power supply to other devices and having an adverse effect. In order to prevent this, filters 9 and 8 are inserted. Note that 40 is a matching circuit. The operating principle of the embodiment shown in FIG. 2 is the same as that of the embodiment shown in FIG. There is a large voltage drop due to the high resistance 5, and this system is in an equilibrium state during normal sputtering.

If the discharge stops for some reason, please contact electrode 7.
As soon as the self-bias disappears, the high voltage of the trigger power source 1 is directly applied to the electrode 6, and re-discharge is easily started.

In the case of the embodiment shown in Fig. 2, it is difficult to overlook that the change in the matching state before and after discharge when used in a high-frequency power source spatter power source, which has been a problem in the past, is reduced, and matching adjustment becomes easier. There are also effects.

Since the method of the present invention is as described above, as is clear from the above explanation, it is sufficient to simply add a trigger power source and some circuits to a normal sputtering device, and the effect is outstanding.

It becomes possible to continuously maintain extremely stable discharge. Therefore, the thin film products manufactured by the method of the present invention have many advantages such as stable quality and improved yield.

The industrial value of the present invention is extremely high.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an embodiment of the method of the present invention in which a DC power source is used as a dedicated sputter power source. FIG. 2 is a schematic diagram of another embodiment in which a high frequency power source is used as the sputter power source. 1...Trigger power supply, 2...Dedicated spatsuta power supply,
3, 4... Diode, 5... High resistance, 6... Electrode shield plate, 7... Sputter electrode, 8 and 9...
...Low-pass filter, 10...Vacuum container, 11...Substrate holder, 40...Impedance matching circuit.

Claims (1)

[Claims] 1. In a sputtering device used to form a thin film, in addition to the main power supply exclusively for sputtering, a high-voltage power supply for a discharge trigger having an output impedance and voltage higher than the output impedance of the dedicated power supply is arranged in parallel. A discharge trigger method for sputtering equipment featuring: