JPS61130485A - Vacuum monitor device - Google Patents

Abstract

PURPOSE:To make possible the control of a remaining gas in the stage of film formation regardless of the condition in a vacuum chamber by coupling an analysis chamber having a high vacuum evacuation system via a pressure conversion orifice to the vacuum chamber and disposing a quadrupoll mass spectrometer in the analysis chamber. CONSTITUTION:The analysis chamber 12 is communicated and coupled with the vacuum chamber 1 which is used to monitor the partial pressure of the remaining gas and a sluice valve 13 is provided between the chamber 1 and the chamber 12. The pressure conversion orifice 14 for the purpose of providing a pressure difference is provided between the chamber 1 and the chamber 12. The inside of the chamber 12 is evacuated to a high vacuum state by a high vacuum pump 15 and is provided with the quadrupole mass spectrometer 10. The pressure in the chamber 1 is converted to the pressure measurable with the spectrometer 10 by the orifice 14 and such pressure is introduced into the chamber 12 where the partial pressure of the remaining gas is measured by the spectrometer 10. As a result, the control of the remaining gas during sputtering which heretofore was impossible is made possible and the quality of the formed film is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vacuum monitoring device for monitoring the quality of vacuum during film formation in various vacuum devices used for film formation, particularly in sputtering devices.

[Conventional technology]

A conventional device of this type is shown in Figure 3.
In the figure, 1 is a vacuum chamber, 2 is a sputter target module, 3 is a high vacuum pump, 4 is a pre-evacuation chamber for loading, 5 is a pre-evacuation chamber for unloading, 6 is a transfer system in the vacuum chamber 1, and 7 is a membrane 8 is a high vacuum measurement gauge, 9 is a low vacuum measurement gauge, 1O is a quadrupole device, and the analyzer 11 is an Ar gas flow rate control system.

Next, the operation will be explained. The purity of the film formed by the sputtering device is determined by the residual gas (
(H2O, N2, 02, etc.). Therefore, in order to obtain a good quality film, it is necessary to control this residual gas to a predetermined value or less.

In the conventional sputtering apparatus shown in FIG. 3, the amount of residual gas is controlled using a high vacuum measurement gauge 8 such as an ionization vacuum needle or a quadrupole mass spectrometer 10.

That is, when forming a film in a conventional sputtering apparatus, the inside of the vacuum chamber 1 is first evacuated by a high vacuum pump 3, and the degree of vacuum reached at that time is read by a high vacuum measuring gauge 8, or the quadrupole mass is The residual gas partial pressure is read by the analyzer 10, and it is determined to be a predetermined value (for example, 5
(OTorr) or less.

Next, an Ar gas main for causing a glow discharge is introduced into the vacuum chamber 1, and the pressure inside the chamber 1 is set to a predetermined value using a low vacuum measuring gauge 9 such as a Villany gauge Schulz type ionization vacuum type or Baratron gauge. (e.g. 2~20X
10-3 Torr).

Thereafter, a high voltage is applied to the sputter target 2 for the first time to cause glow discharge, and a film is formed by sputtering.

[Problem that the invention seeks to solve]

In conventional equipment, the vacuum chamber 1 is
Since we are checking the residual gas in the air, we are checking the Ar
It is fine if the gas supply is stopped and the chamber 1 is evacuated to a high vacuum, but as in a continuous type device, Ar gas is continued to flow into the vacuum chamber 1 to maintain the glow discharge. The method in which film formation is carried out while the substrate 7 is taken in and out using the loading preliminary exhaust chamber 4 and the unloading preliminary exhaust chamber 5 has the disadvantage that residual gas during film formation cannot be controlled at all. Ta. This is because in the latter method, Ar gas is constantly flowing inside the vacuum chamber 1 and the pressure is 2 to 20 x 10T orr.
0 cannot be used, and the low vacuum measurement gauge 9 cannot detect residual gas of 5×1 O −7 Torr (corresponding to 25 to 250 ppm+ of the total pressure) in the atmosphere at all.

The present invention was made to eliminate the above-mentioned drawbacks of the conventional devices, and an object of the present invention is to provide a vacuum monitoring device that can accurately monitor residual gas in a vacuum chamber.

[Means for solving problems]

The vacuum monitoring device according to the present invention is such that an analysis chamber having a high vacuum evacuation system is connected to a vacuum chamber via a pressure conversion orifice, and a quadrupole mass spectrometer needle is disposed within this analysis chamber. .

[Effect]

In this invention, residual gas partial pressure in a vacuum chamber is converted by a pressure conversion orifice into a pressure that can be analyzed by a quadrupole mass spectrometer, and introduced into an analysis chamber, where it is analyzed by a quadrupole mass spectrometer needle. It is.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a vacuum monitoring device according to one embodiment of the present invention. In the figure, 51 is a vacuum chamber in which residual gas partial pressure is to be monitored, 12 is an analysis chamber connected to the vacuum chamber 1 in communication, 13 is a gate valve provided between the vacuum chamber 1 and the analysis chamber 13, and 14 15 is a pressure conversion orifice for creating a pressure difference between the vacuum chamber 1 and the analysis chamber 12;
16 is a heater for baking the analysis chamber; 10 is a quadrupole mass spectrometer needle attached to the analysis chamber 12;
17 is an alarm circuit that issues an alarm when the output signal of the quadrupole mass spectrometer 10 exceeds a set value.

Next, the effects will be explained.

Residual gas in vacuum chamber 1 (H2O, N2゜02, etc.)
The upper operating pressure limit of the quadrupole mass spectrometer 10 that can measure partial pressure is approximately 2×10 Torr;
The pressure inside the vacuum chamber 1 during sputtering is 2 to 20
X 10 Torr, quadrupole mass spectrometer 10
The pressure is 100 to 1000 times higher than the upper limit of operating pressure.

For example, consider a case where the internal pressure of the vacuum chamber 1 is 10 mTorr. Quadrupole mass spectrometer 10
; In order to operate at Torr, it is necessary to reduce the internal pressure of the vacuum chamber 1 to 11,500, and for that purpose, an analysis chamber 12 separate from the vacuum chamber 1 is provided, and an orifice 14 for pressure conversion is inserted between them. The interior of the chamber 12 may be evacuated using the high vacuum pump 15.

The orifice 14 has a diameter of about 1.0 to 2.0 mm under a normal sputtering pressure of 2 to 20 X 10 Torr, although it varies depending on the pressure conversion ratio.

In this way, analysis can be performed at approximately 2X10 Torr, which is the operating pressure of the quadrupole mass spectrometer lO, but since the pressure conversion orifice 14 is used, if the pressure conversion ratio is R, the residual gas The pressure is also approximately 1/R. Using the previous example, the residual gas partial pressure of 5X10 Torr is 11500, and lXl0 To
It is detected as rr.

Therefore, the background of the residual gas partial pressure in the analysis chamber 12 is reduced to 1 (l) using the analysis chamber baking heater 16.
It is necessary to lower it to the Torr range.

In this apparatus, even if the pressure inside the vacuum chamber 1 is the same as that during sputtering, the residual gas analysis is performed by the quadrupole mass spectrometer 10, and the output of each residual gas partial pressure is performed by the quadrupole mass spectrometer 10. The signal value is processed in an alarm circuit 17 and compared with a set voltage corresponding to a control limit value, and an alarm is issued if an unexpected leak during sputtering 8 is detected, such as excessive residual gas intrusion from the preliminary exhaust chamber. ,
Further, the power of the sputtering apparatus (not shown) is turned off by the output of the alarm circuit 17.

In the apparatus of this embodiment as described above, the pressure in the vacuum chamber is converted by the pressure conversion orifice into a pressure that can be measured by a quadrupole mass spectrometer, and then introduced into the analysis chamber, where it is measured by the quadrupole mass spectrometer. Since the residual gas partial pressure is measured, it becomes possible to manage the residual gas during sputtering, which was previously impossible, and the quality of the film formed by sputtering can be improved.

In addition, this device uses an alarm circuit to process the output of the quadrupole mass spectrometer needle and issue an alarm, making it easy to manage residual gas.Furthermore, the output of the alarm circuit automatically turns off the power to the device. It becomes possible to perform processing such as turning off the film, thereby guaranteeing the reliability of the device and film quality.

In the above embodiment, only the partial pressure of one residual gas (for example, N20) is monitored, but as shown in FIG. gas (for example, N20.N2.02.
If the partial pressures of Ar, N2) are processed by the time division circuit 18 and an alarm circuit 17 is provided for each residual gas partial pressure, it becomes easy to turn on/off the supply and take countermeasures when troubles related to vacuum occur. For example, in the case of an alarm caused by N2, there may be an air leak, and in the case of N20, there may be a water leak or a large amount of residual gas brought in from the preliminary exhaust chamber. Furthermore, by monitoring the residual gas partial pressure of Ar and feeding it back to the Ar flow rate control system 11, it is also possible to control the Ar pressure, resulting in a total vacuum monitoring system.

〔Effect of the invention〕

As described above, according to the present invention, an analysis chamber is provided that is connected to a vacuum chamber via a pressure conversion orifice and has a high vacuum exhaust system, and residual gas analysis can be performed using a quadrupole mass spectrometer needle in the analysis chamber. This has the effect of making it possible to manage residual gas regardless of the state inside the vacuum chamber.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a vacuum monitoring device according to one embodiment of the present invention, Fig. 2 is a block diagram of a vacuum monitoring device according to another embodiment of the present invention, and Fig. 3 is a residual gas detection method in a conventional sputtering device. FIG. 1... Vacuum chamber, 10... Quadrupole mass spectrometry needle,
12...Analysis chamber, 14...Pressure conversion orifice, 1
5... High vacuum pump for exhausting the analysis room (high vacuum exhaust system). Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A vacuum chamber in which residual gas partial pressure is to be monitored, an analysis chamber connected in communication with the vacuum chamber, a high vacuum evacuation system that maintains the inside of the analysis chamber in a high vacuum state, and a A quadrupole mass spectrometer that analyzes the partial pressure of the residual gas introduced into the analysis chamber, and a quadrupole mass spectrometer that can analyze the partial pressure of the residual gas introduced from the vacuum chamber to the analysis chamber. A vacuum monitoring device characterized by comprising a pressure conversion orifice that converts pressure into pressure.