JPH05226296A - Monitoring method for abnormal discharge of sputter etching apparatus - Google Patents

Abstract

PURPOSE:To improve reliability of processing by monitoring an abnormal discharge in an apparatus by an etch end point detector by plasma light emission analysis during sputter etching process, and using the emission wavelength of Ar in an emitting light spectrum as a wavelength to be monitored. CONSTITUTION:An etch end point detecting system by a plasma light emission analysis is of one wavelength type and a differentiated waveform detecting type. In this system, an emitted light in argon sputter etching process is received by a glass fiber 7 provided out of a processing chamber 1, an intensity of a light emitted through a spectroscope 8 and a filter 9 of 705nm is converted to an electric signal and monitored. Then, an Ar plasma is stabilized at the time of ordinary processing, but the intensity of 705nm at the time of abnormal discharging is extremely weakened. Thus, an abnormal discharge generated during sputter etching can be monitored thereby to improve reliability of the processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for monitoring abnormal discharge in a sputter etching apparatus.

[0002]

2. Description of the Related Art Argon sputter etching (ASE) is a method of flattening a substrate surface in a wiring process. this is,
ASE is used to remove the overhanging portion of the film deposited on the surface of the substrate for flattening. Normally, ASE is performed for a certain period of time when the wiring film is deposited.

However, it is difficult to inspect abnormalities from a wafer or a test piece that has undergone ASE, and
ASE had to rely on the stability of the equipment to carry out the processing without any anomaly monitoring.

In an etching process that normally involves a chemical reaction,
Using the etch end point detector (EPD, End Point Detector),
The end point of etching is detected by reading the emission wavelength from the molecules of the reaction product generated from the film to be etched and the plasma of the reaction gas.

On the other hand, since argon sputter etching works only by physical factors, it is not necessary to use an etch end point detector. Therefore, only the pattern etching process was performed for a fixed time, and the process state was not monitored during that period. Further, as described above, it is difficult to find an abnormality in the wafer after the sputter etching process, so it is necessary to immediately stop the process when the apparatus is abnormal.

[0006]

One of the most dangerous obstacles during the sputter etching process is abnormal discharge in the processing equipment. If the occurrence of abnormal discharge during processing is not monitored,
There is a problem that even if abnormal discharge occurs, it cannot be detected from the processed wafer.

An object of the present invention is to improve the reliability of the process by making it possible to monitor abnormal discharge that occurs during the sputter etching process.

[0008]

[Means for Solving the Problems] To solve the above problems, 1) Monitor an abnormal discharge of a sputter etching apparatus that monitors an abnormal discharge in a processing chamber by monitoring the emission intensity of gas plasma during a sputter etching process on a semiconductor wafer. Method, or 2) a wavelength of 70 in the emission spectrum of the gas plasma
This is achieved by the abnormal discharge monitoring method of the sputter etching apparatus described in 1) above, which monitors the emission intensity of 5 nm.

[0009]

The present invention monitors abnormal discharge in the equipment during the sputter etching process by using the etching end point detector by plasma emission analysis, which was not necessary in the past, and the monitoring wavelength is the emission wavelength of Ar in the emission spectrum. A certain 705 nm was used. The reason for using this wavelength as the monitoring wavelength is that the change in emission intensity between normal processing and occurrence of abnormal discharge is the largest compared to the case of using other wavelengths.

[0010]

1 is a block diagram of an embodiment of the present invention. In the figure, 1 is a processing chamber, 2 is a gas inlet, 3 is an exhaust port, 4
Is a substrate side electrode, 5 is a counter electrode, 6 is an RF power supply, 7 is an optical fiber, 8 is a spectroscope, 9 is a filter, 10 is a recorder, and W
Is a wafer.

As the etching end point detection method by plasma emission analysis, a one-wavelength type differential waveform detection method was used.
The light emitted during the argon sputter etching process is received by the glass fiber provided outside the processing chamber, and the light passing through the spectroscope is emitted.
The emission intensity is converted into an electric signal through a 705 nm filter and monitored.

Ar plasma is stable during normal processing, but the emission intensity at 705 nm becomes extremely weak during abnormal discharge. At this time, any type of argon sputter etching can be used, and the sputter gas may be a mixture of Ar with an inert gas (N ₂ , He, etc.) other than Ar.

[0013]

According to the present invention, it becomes possible to monitor the abnormal discharge that occurs during the sputter etching process, and it is possible to improve the reliability of the process.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

[Explanation of symbols]

 1 Processing Chamber 2 Gas Inlet 3 Exhaust 4 Substrate Side Electrode 5 Counter Electrode 6 RF Power Supply 7 Optical Fiber 8 Spectroscope 9 Filter 10 Recorder W Wafer

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Claims (2)

[Claims] 1. A method for monitoring abnormal discharge in a sputter etching apparatus, which comprises detecting emission intensity of gas plasma during a sputter etching process on a semiconductor wafer to monitor abnormal discharge in a processing chamber. 2. The method for monitoring abnormal discharge of a sputter etching apparatus according to claim 1, wherein the emission intensity at a wavelength of 705 nm is monitored in the emission spectrum of the gas plasma.