JP2787503B2 - Plasma processing equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a plasma processing apparatus using a DC glow discharge, for example, a plasma processing apparatus such as an ion nitriding apparatus, a gas carburizing apparatus, and an ion plating apparatus.

(Prior Art) As an example of this type of apparatus, an apparatus having an ion nitriding function will be described with reference to FIG. here,
The processing chamber includes three vacuum vessels 41A, 41B, and 41C, and a DC voltage is selectively supplied from one DC power supply 42 to these vacuum vessels.

A vacuum pump 43 for roughing and a vacuum pump 44 for ordinary use are connected to the vacuum vessel 41A via a valve, and an H ₂ gas supply source 45 and an Ar gas are supplied via a valve and a flow rate controller for each supply source. A supply source 46 and an N ₂ gas supply source 47 are connected. The same applies to the vacuum containers 41B and 41C.

When performing the ion nitriding process in the vacuum vessel 41A, as is well known, the material to be processed is accommodated in the vacuum vessel 41A, and then the vacuum pumps 42 and 43 evacuate. After a predetermined reduced pressure state is obtained, H _2, Ar, N ₂ gas was supplied at any ratio from the H ₂ gas supply source 45, Ar gas supply source 46, N ₂ gas supply source 47 to the vacuum chamber 41A, Thereafter, a DC voltage is supplied from the DC power supply 42 to generate a DC glow discharge in an H ₂ , Ar, N ₂ gas atmosphere, and the nitriding process starts.

(Problems to be Solved by the Invention) This device supplies power from the DC power supply 42 to one of the vacuum vessels 41A to 41C by switching a switch, and only one vacuum vessel can be operated at any time. It is.

On the other hand, in the case of an apparatus having a plurality of vacuum vessels, it is desirable that different materials to be processed can be processed in parallel. However, when the materials to be processed are different, not only the processing time but also the heating rate and the driving voltage are different. For example, a light-weight material such as a stainless steel plate is quickly heated and requires a low driving voltage, but a heavy material is slow and requires a high driving voltage. For this reason, parallel processing of different materials to be processed has not been possible with conventional devices.

An object of the present invention is to provide a plasma processing apparatus capable of processing different materials to be processed in a plurality of processing chambers in parallel by improving a power supply means.

(Means for Solving the Problems) The plasma processing apparatus according to the present invention includes a plurality of processing chambers in which processing proceeds simultaneously, and the plurality of processing chambers are supplied from one power source according to the material to be processed in each processing chamber. Control means for supplying a pulsed drive voltage in a divided manner is provided.

(Operation) The control means in the present invention controls the voltage supplied to each processing chamber based on a control pattern predetermined according to the material to be processed in the processing chamber. The voltage is controlled by changing the width, generation cycle, and number of the pulse-like voltages.

(Embodiment) An embodiment of the present invention will be described with reference to FIGS.

In FIG. 1, the case where there are two vacuum chambers as processing chambers will be described here for easy understanding. One DC power supply 2 is provided as a current supply system to the vacuum vessels 1A and 1B, and a pulsed driving voltage is supplied to the vacuum vessels 1A and 1B in a time-division manner via switching circuits 3A and 3B.
The control of the pulse-like drive voltage is performed by a control system including a control unit 4 and a pulse control unit 5 as described later.
The control unit 4 performs control such that a predetermined voltage pattern is drawn in accordance with the material to be processed, and performs voltage control based on signals from the temperature detectors 6A and 6B installed in each of the vacuum vessels 1A and 1B. . Exhaust system of each vacuum vessel 1A, 1B,
The various gas supply systems may be the same as those shown in FIG.

The control unit 4 can set a plurality of types of power supply patterns according to the material to be processed. The control unit 4 controls the pulse control unit 5 based on the set power supply pattern, and controls the output of the switching circuits 3A and 3B. The cycle and the number of the pulse-like drive voltages are controlled. The time range for pulse generation to the vacuum vessel 1A does not overlap with the time range for pulse generation to the vacuum vessel 1B.

FIG. 2 shows an example of a power supply pattern set in the control unit 4. When the material 7B accommodated in the vacuum vessel 1B is larger than the material 7A accommodated in the vacuum vessel 1A, the electric power supply pattern supplied to the vacuum vessel 1A (FIG. 2A) The power supply pattern (FIG. 2b) supplied to the vacuum vessel 1B also becomes large. In FIG. 2, a hatched area indicates a heating or cooling process, and a region parallel to the time axis indicates a soaking process.

 Next, the operation will be described.

The materials 7A and 7B to be processed are accommodated in the vacuum vessels 1A and 1B, respectively, and a power supply pattern is set so that a predetermined evacuation operation is performed.
After performing the gas supply operation, the control unit 4 starts power supply. First, the control unit 4 has the vacuum vessel 1A
In order to draw the rising pattern shown in FIG.
The pulse controller 5 is controlled to supply a pulsed voltage having a large number of pulses per unit time to the vacuum vessel 1A. Vacuum container 1A
Is completed, the control unit 4 supplies a reduced number of pulses per unit time to the vacuum vessel 1A by a predetermined number so as to perform the soaking process.

The control unit 4 also controls the pulse control unit 5 based on a pattern as shown in FIG. 2 (b) in order to start raising the temperature of the vacuum vessel 1B, so that the time does not overlap with the control time range of the switching circuit 3A. Switching circuit 3B is turned on in the
Control off.

FIG. 3 shows the pulse-shaped drive voltage when the vacuum vessel 1A is performing the soaking process (FIG. 3a) and the vacuum vessel 1B is increasing the temperature (FIG. 3b).

The control unit 4 also performs feedback control based on detection signals from the temperature detectors 6A and 6B. That is, when the temperature in the vacuum vessel fluctuates for some reason, the pulse control unit 5 is controlled so as to compensate for this temperature fluctuation. When the temperature fluctuation in the vacuum vessel is small, the above-mentioned feedback system is unnecessary.

Further, the present invention is not limited to the above embodiment, and may be realized by controlling the widths of the pulsed voltages supplied to the respective processing chambers so that they do not overlap with time. In this case, the pulse width control can also be realized by the ignition control means for controlling the conduction angle of the switching circuits 34A and 34B.

(Effects of the Invention) As described above, according to the present invention, since a plurality of processing chambers are provided with control means capable of individually controlling the voltage from one DC power supply, the shape, processing conditions, and the like differ. The material to be treated can be subjected to the surface treatment in parallel and the surface heat treatment step can be greatly shortened.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of one embodiment of the present invention, and FIG.
FIG. 3 shows an example of a power pattern supplied to the vacuum vessel shown in FIG. 3, FIG. 3 shows an example of a pulsed voltage supplied to the vacuum vessel shown in FIG. 1, and FIG. Schematic configuration of conventional plasma heat treatment equipment, where 1A and 1B are vacuum vessels, 2 is a DC power supply, 3A and 3B are switching circuits, 4 is a control unit, 5 is a pulse control unit, and 6A and 6B are temperature detectors. , 7A, 7B are materials to be processed.

Claims (1)

(57) [Claims] 1. A plasma processing apparatus using a DC glow discharge, comprising a plurality of processing chambers in which processing proceeds simultaneously.
A plasma processing apparatus comprising a control unit for supplying a pulsed driving voltage in a time-division manner from one power supply to one of the plurality of processes in accordance with a material to be processed in each processing chamber.