JP3146721B2 - Device for detecting the limit of use of high-frequency electrodes in plasma processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, an FP
D, LCD, CD, etc., a high-frequency power supply (hereinafter referred to as “R
F power supply) to detect a current limit supplied to the high-frequency electrode (hereinafter, referred to as "RF electrode"), thereby detecting the limit of use of the RF electrode. It concerns the device.

[0002]

BACKGROUND OF THE INVENTION Figure 4 a general plasma processing apparatus shown in schematic view. The plasma processing apparatus P is widely used, for example, for forming a thin film on a surface of a semiconductor wafer or etching the surface in a semiconductor device manufacturing process.

[0003] The plasma processing apparatus P includes a chamber 20.
Is provided with an RF electrode comprising an anode electrode 21 and a cathode electrode 22, and a workpiece W is placed on the cathode electrode 22 to evacuate the chamber 20.

[0004] In this state, for example, a 60-phase AC power from the commercial three-phase AC power supply 30 through the power cables 1R, 1S and 1T.
Hz, 200 V three-phase alternating current is supplied to the RF power supply 31, and the RF power supply 31 uses, for example, 100 kHz to 13.56.
A high-frequency current of 0 W to 3 KW in MHz is generated, and this high-frequency current is applied to the anode electrode 21 and the cathode electrode 22 via a capacitor 32 to generate a desired plasma discharge.

In general, the current supplied from the RF power source 31 to the RF electrodes 21 and 22 is large when the plasma discharge is at a high output, and at the same time , the RF power is exposed to the plasma. > The consumption speed of the poles 21 and 22 is also increased. Conversely, when the plasma discharge has a low output, the current decreases, and the consumption rate of the RF electrode also decreases.

It is often the case that different workpieces W are processed by sharing the plasma processing apparatus P, and the intensity of the plasma discharge must be changed depending on the type and processing of the workpiece W. Reference RF power applied to the RF electrodes 21 and 22 (hereinafter, “RF electrode reference output conditions”
For example), for example, at 600 W for 180 hours, for example, at 300 W for 180 hours of RF power or 750
Apply W RF power for 180 hours at W.

In any case, the RF electrodes 21 and 22 deteriorate as they are used for a long time, and accordingly, a predetermined plasma is not generated. Usually this RF electrode
Of the anode electrodes 21 and 22 , the anode electrode 21 is represented by amorphous carbon or hard anodized having many small holes.
Surface-treated aluminum etc. are used, and this is left
If you do, amorphous carbon will fly as dust
Since the small holes are scattered and the small holes are broken and uniform plasma discharge is not performed, and the surface treatment of the workpiece W is difficult to be performed well and uniformly, as a countermeasure,
Only the time during which the RF current is being output from the RF power source 31 is integrated, and when this integrated time reaches a predetermined time, it is determined that the RF electrodes 21 and 22 have reached the usage limit, and The RF electrodes 21 and 22 are replaced with new RF electrodes.

[0008]

However, this method has a disadvantage that the limit of use of the RF electrode cannot be accurately detected. That is, 1. After the replacement of the RF electrode until the next replacement time,
When the RF output higher than the reference output condition of the RF electrode is used in combination, the RF electrode reaches a use limit before the next replacement time, and dust is generated as described above,
Uniform processing cannot be performed on the workpiece. Conversely, if an RF output condition lower than the reference output condition of the RF electrode is used together, the integration time reaches a predetermined time, indicating a replacement time, and the RF electrode that has not yet reached the use limit is discarded. Often happens.

[0009] 2. When changing the RF output condition, it is necessary to change the detection set value every time in order to avoid the above-mentioned problem, but this is a troublesome operation. The present invention aims to eliminate these disadvantages of the prior art.

[0010]

Therefore, an apparatus for detecting the limit of use of an RF electrode in a plasma processing apparatus according to the present invention comprises:
A current converter is coupled to a power supply circuit of a plasma processing apparatus that generates a plasma discharge by supplying a high-frequency current to an RF electrode, and a power integrator and a display for displaying the output are connected to an output side of the current converter. The above problem was solved by integrating and displaying the amount of power supplied to the RF electrode based on the output voltage of the RF electrode.

[0011]

Therefore, the apparatus for detecting the limit of use of an RF electrode according to the present invention can detect an accurate limit of use of an RF electrode.
It can be confirmed accurately using a display.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
The use limit detecting device for the F electrode will be described. FIG. 1 is a block diagram showing a state in which the apparatus for detecting the limit of use of an RF electrode of the present invention is coupled to a conventional plasma processing apparatus, and FIG. 2 is a block diagram of the apparatus for detecting the limit of use of an RF electrode of the present invention. FIG. 3 is a circuit diagram schematically showing each configuration of FIG. The same components as those of the conventional plasma processing apparatus P shown in FIG. 4 are denoted by the same reference numerals, and the description thereof will be omitted.

An apparatus for detecting the limit of use of an RF electrode D according to the present invention
As shown in FIG. 1 and FIG. 2, a current converter A used for plasma generation is connected to a three-phase AC power supply, and a power integrator B is connected to the output side.

Further, the current converter A
Are current detection coils 2R, 2S, as shown in FIG.
2T, a rectifier circuit 3 connected to the output side thereof, and an output terminal 4 connected to the output side.

As shown in FIG. 1 and FIG. 2, the electric energy integrator B includes a light-shielding device 6 comprising a DC motor 5, a rotary light-shielding plate 6A coupled to a rotating shaft 5a thereof, and a photosensor 6B. It comprises a digital counter 7 and a display 8.

The current detecting coils 2R, 2S, 2T of the current converter A are connected to respective power cables 1R,
1S, 1T and each power cable 1
A three-phase AC current flowing through R, 1S, and 1T is detected, full-wave rectified by a rectifier circuit 3 connected to the output side, and the DC voltage is output to the output terminal 4.

The output DC voltage is applied to the output terminal 4
To the DC motor 5 connected to the DC motor 5, and drives the DC motor 5. As described above, the rotary shaft 5a of the DC motor 5 is coupled with the rotary light shielding plate 6A,
This rotates together with the rotating shaft 5a. This rotating light shielding plate 6A
Are formed at regular intervals around the periphery of the opening.

The photosensor 6B includes a light emitting diode 6Ba and a light receiving transistor 6Bb, and a peripheral portion of the rotary light shielding plate 6A is interposed between the light emitting diode 6Ba and the light shielding diode 6Ba. It constitutes a so-called rotary encoder 6 that blocks or transmits light.

The digital counter 7 has a power terminal 7A.
, A digital signal input terminal 7B, a ground terminal 7C, an output terminal 7D on the output side, and a display panel 7 on the front.
E is provided. The “limit value of RF electrode use under the reference output condition” is input to the digital counter 7 in advance.

The collector of the light receiving transistor 6Bb is connected to a power supply terminal 7A, and the emitter is connected to the digital signal input terminal 7B. The light emitting diode 6Ba is connected between the power supply terminal 7A and the ground terminal 7C. The pulsed light signal from the light emitting diode 6Ba transmitted through the rotary light shielding plate 6A which rotates according to the rotation speed of the DC motor 5 is converted into an electric digital signal by a light receiving transistor 6Bb, It is supplied to the signal input terminal 7B.

In the digital counter 7, the digital signal is added or subtracted, and whether or not the value has reached the "RF electrode use limit value under the reference output condition" is numerically displayed on the display panel 7E. A display 8 that can be visually and visually confirmed such as a lamp or a buzzer connected to the output terminal 7D.
To display.

That is, the RF current value supplied from the RF power supply to the RF electrode is large when the plasma discharge has a high output,
Conversely, when the plasma discharge has a low output, the current is small, so that the DC output voltage of the rectifier circuit 3 fluctuates, and the rotation speed of the DC motor 5 fluctuates according to the fluctuation.
The frequency of the digital signal generated on the output side of the light receiving transistor 6Bb also varies.

Therefore, the digital counter 7
When the RF current has a high output, a high frequency digital signal is integrated quickly, and when the RF current has a low output, a low frequency digital signal is integrated late. Then, when the integrated value reaches the "RF electrode use limit value under the reference output condition" previously input to the digital counter 7, the display 7E or 8 displays the use limit of the RF electrode. can do. Therefore, by watching this display, the working technician can know the life of the RF electrode currently used.

[0024]

As is apparent from the above description, the apparatus for detecting the limit of use of an RF electrode according to the present invention has a plurality of RF electrodes applied to the RF electrode after the replacement of the RF electrode until the next replacement time.
Even if you use it like applying power under output conditions,
Since the limit of use of the RF electrode can be accurately detected,
An RF electrode that is always in good condition can be used.

Therefore, troubles due to generation of dust and uneven processing can be prevented, and the RF electrodes are not wasted. Furthermore, R
Each time the RF output condition of the F power supply is changed, the detection set value is changed. However, various excellent effects are obtained in that the troublesome work is not required.

[Brief description of the drawings]

FIG. 1 shows a conventional plasma processing apparatus having an RF of the present invention.
FIG. 2 is a configuration diagram showing a state in which an electrode usage limit detection device is coupled.

FIG. 2 is a configuration diagram of an RF electrode usage limit detecting apparatus according to the present invention.

FIG. 3 is a circuit diagram schematically showing each configuration of FIG. 2;

FIG. 4 is a schematic diagram of a general plasma processing apparatus .

[Explanation of symbols]

Reference Signs List A Current converter B Electric power integrator D High-frequency (RF) electrode usage limit detection device P Plasma processing device W Workpiece 1R Power cable 1S Power cable 1T Power cable 2R Current detection coil 2S Current detection coil 2T Current detection coil 3 Rectification Circuit 4 Output terminal 5 DC motor 5a Rotary shaft 6 Rotary encoder 6A Rotary light shielding plate 6B Photo sensor 6Ba Light emitting diode 6Bb Light receiving transistor 7 Digital counter 7A Power supply terminal 7B Digital signal input terminal 7C Ground terminal 7D Output terminal 7E Display panel 8 Display 20 Chamber 21 Anode electrode 22 Cathode electrode 30 Three-phase AC power supply 31 High frequency (RF) power supply 32 Capacitor

Claims (1)

(57) [Claims] In a power supply circuit of a plasma processing apparatus for generating a plasma discharge by supplying a high-frequency current to a high-frequency electrode, a current converter is coupled to the power supply circuit, and a power amount integrator and an output thereof are displayed on an output side thereof. Connected to the display, based on the output voltage of the current converter,
An apparatus for detecting the limit of use of a high-frequency electrode in a plasma processing apparatus, wherein the apparatus is configured to integrate and display an amount of power supplied to the high-frequency electrode.