JPH0436271B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for monitoring abnormalities in a vacuum pump used in a vacuum device such as a sputtering device or a dry etching device.

(Prior art) Vacuum pumps used in sputtering equipment, dry etching equipment, etc. that process the surface of substrates must be reliable enough to withstand long-term operation, so it is important to maintain the equipment carefully. carried out,
Failures during operation must be avoided.

In particular, for equipment that uses a turbo molecular pump as the main pump, consider the mechanical life of the pump.
In addition to regular inspections, early detection of malfunctions must be carried out.

Therefore, conventionally, the overcurrent k shown in FIG. 2 is detected among the drive current of the turbo molecular pump, and the failure of the device is confirmed by detecting the overcurrent k.

However, this overcurrent k flows especially when the pump load is large, such as when starting a vacuum pump, and it rarely flows during steady operation with a low load. do not have.

(Problems to be Solved by the Present Invention) Therefore, in the conventional device, there was a problem in that an abnormality could only be detected in a specific operating state such as when the vacuum pump was started.

An object of the present invention is to provide a state in which abnormalities in the vacuum pump can be detected at any time simply by closing the valve, so that the abnormalities can be discovered at an early stage.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a vacuum pump for evacuating a vacuum chamber, a drive power source for operating this vacuum pump, and a drive source from this drive power source. A drive current detection means for detecting current; a valve for communicating or cutting off the communication between the vacuum chamber and the vacuum pump; and abnormality detection means for determining whether the vacuum pump is large or small and detecting an abnormality in the vacuum pump.

(Operation of the present invention) With the above structure, by closing the valve, it is possible to artificially create a steady operating state with a low load, and in this state, the abnormality detection means automatically operates to It is possible to detect abnormalities in

(Effects of the Invention) According to the invention described in claim 1, an abnormality in the vacuum pump can be detected at any time by closing the valve, which makes it easier to detect the abnormality at an early stage.

According to the invention recited in claim 2, in addition to artificially creating a steady operating state by closing the valve and detecting the abnormality, the abnormality is always detected even in the actual steady operating state of the vacuum pump. Abnormalities can be detected. Therefore, there are more opportunities to detect an abnormality in the vacuum pump, which is useful for early detection of the abnormality.

(Embodiment of the present invention) In the embodiment shown in FIG. 1, a turbo molecular pump 3 (hereinafter referred to as a vacuum pump) as a main pump is connected to a vacuum chamber 2 to which a vacuum gauge 1 is connected. A valve 4 is connected between the chamber 2 and the vacuum pump 3.

Note that 5 is an oil rotary pump as an auxiliary pump, and 6 is a valve for introducing gas into the vacuum chamber 2.

A drive power source 7 for driving the vacuum pump 3 is connected to the vacuum pump 3 as described above, and a drive current detection means 8 is connected to the drive power source 7.

The drive current detection means 8 is connected to an abnormality detection means 9, which is also connected to the vacuum gauge 1 and the valve 4. The abnormality detection means 9 operates either when the valve 4 is closed or when the pressure within the vacuum chamber 2 falls below the set pressure.

Moreover, the abnormality detection means 9 is stored with an appropriate drive current during steady operation with a low pump load, and when the drive current output from the drive current detection means 8 is larger than the above-mentioned appropriate value, the difference is detected. Judgment is made to detect an abnormality, and the abnormality signal is sent to alarm means 1.
I am trying to transmit it to 0.

Therefore, when the vacuum pump 3 is driven with the valve 4 closed, the suction volume is only the volume of the pipe connecting the valve 4 and the vacuum pump 3.
The vacuum pump 3 is in a state where there is no load on the seat or a state close to that. That is, by closing the valve 4, a steady operating state of the vacuum pump 3 can be artificially created.

Moreover, when the valve 4 is closed, the abnormality detection means 9 operates as described above, so the abnormality detection means 9 measures the drive current output from the drive current detection means 8 and compares the value with the appropriate value. do.

As a result of the comparison by the abnormality detection means 9, if it is determined that the drive current is larger than the appropriate value, it means that the vacuum pump 3 has an abnormality.

In other words, if the drive current is larger than the appropriate value, it is thought that an unnecessarily high load is acting on the pump 3. In this case, bearing wear or lubricating oil abnormality may occur inside the pump 3. Alternatively, there may be an abnormality that leads to performance deterioration, such as the introduction of foreign matter.

The abnormality signal detected in this way is transmitted to the supervisor via the alarm means 10, so that corresponding measures can be taken and maintenance etc. can be carried out reliably.

Further, while driving the vacuum pump 3 to evacuate the inside of the vacuum chamber 2, the pressure inside the vacuum chamber 2 is measured with the vacuum gauge 1, and the pressure signal is transmitted to the abnormality detection means 9.

When the pressure within the vacuum chamber 2 becomes sufficiently low, in other words, when the pump 3 enters steady operation with no load or a state close to it,
The abnormality detection means 9 operates, and the drive current detection means 8
The drive current input from the sensor is measured and compared with the appropriate value.

FIG. 2 shows the relationship between the drive current I and the operation time T after entering steady operation.
Section a closes valve 4 and closes the pump 3.
It is in a state where it is started. In this section a, a large starting current flows, but when the pump 3 reaches its rated rotational speed and enters the starting state, the driving current decreases to g.

Next, in the b section, the drive current decreases as the pressure decreases due to the change in current when the valve 4 is opened to evacuate the vacuum chamber 2, and the current value becomes h at the ultimate pressure state.

C section is the time when gas is introduced to perform work in the vacuum chamber 2, and the pump 3 is
is in a state where a constant load is applied to it.

In the d section, the vacuum chamber 2 is being evacuated again after the work has been completed, but in this example, the pump 3 has begun to deteriorate, and even though the pressure in the vacuum chamber 2 has become sufficiently low, the drive current is is a larger value i than the normal current values g and h.

The e-section is the time when the next step begins and gas is introduced again.

The f section performs the work after introducing the gas, finishes the work, closes the valve 4,
It is now time to return the vacuum chamber 2 to the atmosphere and replace the substrate. During this time period, the performance of the pump 3 has begun to deteriorate as described above, so even though the pump 3 is cut off from the vacuum chamber 2 and is in an unloaded state, the current value j is normal. The drive currents g and h are larger than the drive currents g and h.

From this state, when the valve 4 is opened to evacuate the vacuum chamber 2 in order to repeat the next operation, the drive current I reaches the overcurrent k.

Note that when the drive current I reaches the overcurrent k,
In order to protect the circuit, the drive power supply 7 automatically stops supplying current and stops the operation of the pump 3.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention. Fig. 1 is a circuit diagram of the embodiment, and Fig. 2 shows the correlation between operating time and drive current when a vacuum pump is operated using the device of this embodiment. This is a graph showing 1... Vacuum gauge, 2... Vacuum chamber, 3... Vacuum pump, 4
...Valve, 7... Drive power source, 8... Drive current detection means, 9... Abnormality detection means.

Claims (1)

[Scope of Claims] 1. A vacuum pump for evacuating a vacuum chamber, a drive power source for operating this vacuum pump, a drive current detection means for detecting a drive current from this drive power source, and the vacuum chamber and vacuum pump. An abnormality detection system that detects an abnormality in the vacuum pump by receiving a signal when the valve is closed and determining the amount of current at that time. Vacuum pump monitoring device comprising means. 2 A vacuum gauge is provided to measure the pressure in the vacuum chamber, and when the pressure in the vacuum chamber falls below a set pressure, the abnormality detection means is activated by a signal from the vacuum gauge. Vacuum pump monitoring device as described in Section 1.