JPS61145825A - Cleaning end detection for plasma chemical vapor deposition apparatus - Google Patents

Abstract

PURPOSE:To detect the cleaning end point within a deposition chamber by obtaining an output from a wattmeter which measures a reflection power for discharge input power or from a voltmeter which measures a DC bias voltage of discharge electrode and outputting a signal when a voltage reaches the selectively preset value. CONSTITUTION:After starting glow discharge by into reducing etching into the deposition chamber to which deposited film is adhered, inductance and capacitance of matching circuit 3 are adjusted so that the power indicated by a reflection power meter 4 is minimized. Thereafter, when a thin film adhered to the deposition chamber is removed, a reflection power is increased and the cleaning end point can be monitored by detecting that a reflection power reaches a preset value with an end point detector 5. When a thin film adhered to the deposition chamber, change of DC bias voltage of discharge power can be measured with a bias voltmeter 8, it is detected by the end point detector 5 that the DC bias voltage has reached a preset value and thereby the cleaning end point can be monitored.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention uses etching gas and plasma discharge to remove a thin film deposited within the deposition chamber of a plasma chemical vapor deposition apparatus that deposits a semiconductor thin film or an insulating thin film using plasma discharge. The present invention relates to a method for monitoring the end point of the removal process during the removal process.

Conventional technology Conventionally, as a technique for cleaning all end points in the deposition chamber of a plasma chemical vapor deposition apparatus, for example, "Semiconductor Plasma Process Technology" edited by Takuo Kanno (July 10, 1982)
), Sangyo Tosho, Plll, a monitor system applied to dry etching techniques such as mass spectrometry and emission spectroscopy was applied.

Problems to be Solved by the Invention With such a conventional one-monitor system, it is necessary to install an end point detection device, etc., which is not directly required during thin film deposition, in the plasma chemical vapor deposition apparatus, and the detection device is constantly being monitored. Maintenance required.

The present invention was made in view of such problems, and is based on a reflection power meter originally installed in a plasma chemical vapor deposition apparatus.
It is an object of the present invention to provide a method for easily detecting the end point of cleaning in a deposition chamber using a C bias voltmeter.

Means for Solving the Problems In order to solve the above problems, the present invention obtains the output from a wattmeter that measures the reflected power with respect to the discharge input power or a voltmeter that measures the DC bias voltage of the discharge electrode, and It can output a signal when a set value is reached.

According to the above-described structure, the present invention introduces etching gas into the deposition chamber to which the deposited thin film has adhered, starts glow discharge, and then fixes the inductance and capacitance of the matching circuit, thereby removing the thin film adhered to the deposition chamber. The end point of cleaning can be monitored by a signal output when an increase in reflected power with respect to power applied during discharge is detected and reaches an arbitrary set value.

Embodiment FIG. 1 is a block diagram showing an embodiment of a circuit for monitoring the cleaning end point of the present invention. In Figure 1,
1 is a deposition chamber and 2 is a discharge electrode, to which discharge power is applied by a high frequency power source 7. At this time, the input power is input power meter 6
The inductance and capacitance of the matching circuit 3 are adjusted so that the power shown on the reflected power meter 4 is minimized. Thereafter, when the thin film adhering to the deposition chamber is removed, the reflected power increases, and the end point detector 6 detects that the reflected power has reached a set value, thereby making it possible to monitor the end point of cleaning.

Figure 2 shows the change in reflected power and cleaning end point with respect to the cleaning time when the deposition chamber to which amorphous silicon was deposited was etched with CF, +10%02 etching gas, and the discharge input power was 400 W in one embodiment of the present invention. show. As shown in the figure, the reflected power gradually increases from the cleaning time e, and when the reflected power reaches 40 W, it can be seen that the cleaning has been completed. Therefore, by setting the end point detector 5 of FIG. 1 to a set value of 140 W, the cleaning end point can be easily monitored.

FIG. 3 is a block diagram of a circuit for monitoring the cleaning end point in another embodiment of the present invention.

In this embodiment, when the thin film attached to the deposition chamber is removed, the change in the DC bias voltage of the discharge power is measured by the DC bias voltmeter 8, and the end point detector detects that the DC bias voltage has reached the set value. 6 to monitor the cleaning end point.

Figure 4 shows the deposition chamber with amorphous silicon attached.
, discharge input power 1 using etching gas to +1o%
The change in DC bias voltage and the cleaning end point with respect to the cleaning time when the power is 400W are shown. As shown in the figure, the DC bias voltage begins to decrease from cleaning time 6, and when it reaches -42V, it can be seen that the cleaning has been completed. Therefore, by setting the end point detector 6 of FIG. 3 to the set value f-42V, the cleaning end point can be easily monitored.

Effects of the Invention As mentioned above, the present invention is originally based on plasma CVD.
Required for the device. Using a discharge reflection wattmeter or a DC bias voltmeter, the cleaning end point can be easily monitored with a very simple configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a cleaning end point monitor circuit in one embodiment of the present invention, FIG. 2 is a diagram showing changes in reflected power with respect to cleaning time, and FIG. 3 is a cleaning end point monitor circuit in another embodiment of the present invention. FIG. 4 is a block diagram showing changes in DC bias voltage with respect to cleaning time. 1...Deposition chamber, 2...Discharge electrode, 3.
...Matching circuit, 4...Reflected power meter, 5.
... End point detector, 6 ... Power supply meter, 7
...High frequency power supply, 8...DC bias voltmeter. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Cree;

Claims (1)

[Claims] During the process of removing a semiconductor thin film or an insulating thin film deposited in the deposition chamber of a plasma chemical vapor deposition apparatus using an etching gas and plasma discharge such as glow discharge, the reflected power or plasma electrode with respect to the discharge input power is removed. A cleaning end point detection method for a plasma chemical vapor deposition apparatus, characterized in that the end point of a thin film removal process in the deposition chamber is monitored by measuring a bias voltage generated in the deposition chamber.