JPH05217549A - Calibration of quadrupole mass spectrometer - Google Patents

Abstract

PURPOSE:To enable measurement and detection of leak of the air, etc., in the chamber of a sputtering device with high reproducibility, by carrying out the sensitivity calibration of a spectrometer by using a calibration gas having prescribed mixing ratios of a plurality of elements as analytical objects. CONSTITUTION:A mass flow controller 4 having a full scale of 100sccm is used for Ar, and a mass flow controller 5 having a full scale of 1sccm is used for calibration gas. When Ar at 40sccm, and the calibration gas of 0.07 with N2/Ar=3% are allowed to flow into a vacuum chamber 1, Ar:N2 becomes 1:5.24X10<-5>, and N2 can be calculated to be 52.4ppm. When the peak of a quadrupole mass spectrometer 2 is taken according to the presence of the calibration gas, and the difference of the peak intensities is taken, the increment corresponds to 52.4ppm of N2, and when a vacuum gauge 10 on the differential exhaust side at this time is read, the total pressure is grasped, and the partial pressure of N2 can be calibrated by the total pressure X (52.4ppm+base).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for calibrating a quadrupole mass spectrometer used as a sensor in a sputtering apparatus used for manufacturing an electrode film of a semiconductor device.

In recent years, with the miniaturization and high integration of semiconductor devices, there is a demand for higher quality and higher precision of the films used in the method of forming various films used in the semiconductor devices.
Therefore, the gas sensor used during film formation also requires accurate analysis.

[0003]

2. Description of the Related Art Conventionally, among equipment used in semiconductor manufacturing processes, a sputtering apparatus is often used for forming an electrode wiring metal film.

This sputtering apparatus sputters argon molecules on a metal target for forming an electrode film in a high vacuum,
This is a device for depositing metal that pops out on a semiconductor substrate. When a metal film is sputtered, if there is a minute leak in the vacuum chamber of the sputtering apparatus, it is clear that foreign molecules enter the metal film deposited on the semiconductor substrate and have a great influence on the quality of the metal film in terms of quality. Is becoming

As an example, it is known that when nitrogen molecules or the like are mixed due to leakage, electromigration of the metal film occurs and the frequency of disconnection of the wiring increases.

Therefore, in some of the sputtering devices, a leak detector such as a quadrupole mass spectrometer is attached to the vacuum device to monitor air leakage from the outside. Then, for the sensitivity calibration of the leak detection of this quadrupole mass spectrometer etc., argon (Ar) gas is caused to flow in the vacuum chamber of the sputtering apparatus, and the quadrupole mass is measured at the peak intensity of the argon isotope (m = 36). The sensitivity of the analyzer was adjusted.

[0007]

However, in the sensing part of the quadrupole mass spectrometer, a decrease in sensitivity due to contamination is unavoidable, and it is difficult to measure the absolute amount of leak with good reproducibility. I couldn't get such an effective means. .

An object of the present invention is to provide a means for measuring and detecting leaks of air or the like in a chamber of a sputtering apparatus with good reproducibility by using a quadrupole mass spectrometer.

[0009]

[Means for Solving the Problems] Conventionally, as described above,
Ar gas was caused to flow into the vacuum chamber of the sputtering system, and the sensitivity of the quadrupole mass spectrometer was adjusted by the peak intensity of Ar isotopes (m = 36).

In the method according to the invention, Ar gas is introduced into the chamber.
_{, And} calibration gas (N ₂ /Ar=0.1 to 100%) or air / Ar = 0.1
(100 to 100%) with an accurate mixing ratio and flowing nitrogen (N ₂ )
Adjust the sensitivity of the quadrupole mass spectrometer with the peak intensity of.

That is, an object of the present invention is to calibrate a quadrupole mass spectrometer used to detect a leak in a vacuum chamber by using a calibration gas having a predetermined mixing ratio of a plurality of elements to be analyzed, It is achieved by calibrating the sensitivity of the polar mass spectrometer.

[0012]

By Ar In accordance with the conventional method, it is performed a sensitivity calibration of the quadrupole sensor, a sensitivity to actually Ar, N ₂
There is some variation in the sensitivity to due to the contamination of the sensor and the sensor.

In the low vacuum region (1x10 ^-4 Torr or less)
Since the sensitivity of Ar is affected by the degree of vacuum, accurate calibration of the mass spectrometer is difficult for these two reasons.
According to the present invention, since the partial pressure of Ar and the partial pressure of N ₂ can be independently and accurately mixed in advance, the sensitivity calibration for the N ₂ partial pressure of the core can be accurately performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of an embodiment of the present invention. In the figure, 1 is a vacuum chamber, 2 is a quadrupole mass spectrometer,
3 is a quadrupole sensor, 4 is a mass flow controller for Ar gas, 5 is a mass flow controller for calibration gas, 6 is an orifice, 7 is a differential exhaust system, 8 is a cryopump,
Reference numeral 9 is a vacuum gauge, and 10 is a vacuum gauge.

As shown in FIG. 1, full scale for Ar 1
The mass flow controller 4 of 00 sccm was used, and the mass flow controller 5 of full scale 1 sccm was used for the calibration gas.

Ar was 40 sccm, calibration gas was N ₂ / Ar = 3%, and 0.07 gas was flown. The ratio of N ₂ to Ar at this time was Ar: N ₂ = 40 + (0.07 × 0.97): 0.07 × 0.03 = 40.068: 2.1 × 10 ^-3 = 1: 5.24 × 10 ^-5 , and N ₂ was 52.4ppm. Can be calculated.

FIG. 2 shows the peak of the quadrupole mass spectrometer 2 with and without the calibration gas. If the difference between the peak intensities of N ₂ when the calibration gas is not added as shown in FIG. 2A and when the calibration gas is added is shown in FIG. 2B, the increment is 52.4. It corresponds to ppm N ₂ , and the total pressure can be found by reading the vacuum gauge on the differential exhaust side at this time, so the partial pressure of N ₂ can be calibrated by (total pressure) × (52.4 ppm + base).

By using this method, it is possible to completely calibrate the difference in sensitivity of the quadrupole sensor 3 due to variations in the sensor and the decrease in sensitivity due to contamination, which contributes to stabilizing the film quality of the film formed by the sputtering apparatus. ..

[0019]

As described above, according to the present invention,
External leaks from vacuum chambers used in semiconductor manufacturing equipment can now be detected with good reproducibility using a quadrupole mass spectrometer.

In particular, it contributed to the stabilization of the film quality in the metal film sputtering apparatus.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

[Fig. 2] Gas peak intensity of quadrupole mass spectrometer with and without calibration gas

[Explanation of symbols]

 1 vacuum chamber 2 quadrupole mass spectrometer 3 quadrupole sensor 4 mass flow controller for Ar gas 5 mass flow controller for calibration gas 6 orifice 7 differential evacuation system 8 cryopump 9 vacuum gauge 10 vacuum gauge

Claims (1)

[Claims] 1. In the calibration of a quadrupole mass spectrometer used for detecting a leak in a vacuum chamber, a calibration gas having a predetermined mixing ratio of a plurality of elements to be analyzed is used, and the sensitivity of the quadrupole mass spectrometer is measured. Calibration method for quadrupole mass spectrometer characterized by calibrating