JP2595454B2 - 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 plasma processing apparatus, and more particularly to a plasma processing apparatus capable of performing a thin film forming process or an etching process on a substrate.

[0002]

2. Description of the Related Art In a conventional plasma processing apparatus in which either a cathode coupling or an anode coupling can be arbitrarily selected as a connection method of a power supply system (high-frequency power supply system), a connection is provided between each electrode and a high-frequency power supply. For example, when the switched circuit is operated to connect the cathode electrode and the power supply, the connection between the anode electrode disposed opposite to the cathode electrode and the ground is manually performed using a metal member such as a conductive wire. Had to do.

Further, in a conventional plasma processing apparatus, a variable coil or a variable capacitor is provided for an anode electrode disposed opposite to a cathode electrode to which high frequency power is supplied, in order to adjust the high frequency power flowing through the anode electrode. Are connected. The literature on the connection of a variable coil includes Appl. Phys. Lett 44 (11), 1 Jun
e 1984, and Japanese Patent Application Laid-Open (JP-A) No. 61-204938 is a document in which a variable capacitor is connected. Further, as a modified example of the variable coil, Japanese Unexamined Patent Publication (Kokai) No. 62-111431 discloses a configuration example in which a fixed coil having a switching switch is connected to an anode electrode. These variable coils, fixed coils, or variable capacitors function as a tuning circuit that adjusts the amount of high-frequency power passing therethrough.

[0004]

According to the configuration of the conventional plasma processing apparatus having the high frequency power supply path switching circuit, when the anode electrode is grounded by a conductor, a reactance element is generated in an equivalent circuit. This reactance element is determined according to the dimensional conditions of the conductor and the like, and is generated in a state unintended by the manufacturer, so that the reactance value cannot be controlled. In addition, when the grounding is performed using a metal member such as a conductive wire, the connection between the electrode and the ground is inevitably manually performed, so that the demand for automation or the like cannot be satisfied.

Further, a circuit having a fixed coil or a variable coil or a variable capacitor connected as a grounding circuit for the anode electrode is a circuit having a complete capacitance characteristic from the viewpoint of a high-frequency reactance circuit for adjusting a passing amount of high-frequency power, or It can be configured only as a circuit having perfect inductive characteristics, and has a problem that it does not function as a matching circuit when connected to a high-frequency power supply.

An object of the present invention is to provide a power supply system capable of selectively supplying high-frequency power to one of two opposing electrodes, and desirably selecting an electrode for supplying high-frequency power easily by automatic switching. To provide a plasma processing apparatus.

[0007]

A plasma processing apparatus according to the present invention has, as a basic configuration, a container and an inside of the container.
And second electrodes arranged in a positional relationship facing each other
A gas supply mechanism for supplying gas to the inside of the container;
High frequency power supply for providing high frequency power between the electrode and the second electrode
And a substrate provided on the second electrode, wherein the first electrode
Plasma is generated between the second electrodes to process the substrate. So
The characteristic configuration is that the high frequency power supply has a matching circuit on the first electrode.
Fixedly connected via the first electrode and the second electrode.
Choke carp through a switch between each and the ground
A second electrode is provided between the second electrode and the ground.
Variable reactance to prevent DC from being grounded DC
A circuit was provided. The variable reactance circuit
Includes an inductance element and a variable capacitor.
By adjusting the capacitor, the characteristics ranging from capacitive to inductive
It was configured to have the property. With this configuration, the first
The switch on the pole side is connected and the switch on the second electrode side is connected.
The switch is disconnected so that the cathode coupling
Powering schemes are created, and conversely,
The switch on the first electrode side is disconnected and the switch on the second electrode side is disconnected.
By connecting the above switches, the anode
A pulling power supply configuration is created. Therefore,
In the plasma processing apparatus according to the present invention, a high-frequency power supply is connected to a matching circuit.
(More precisely, the coupling coil described later
Fixedly connected to the first electrode and the substrate is placed
A variable reactance circuit is connected between the second electrode and ground.
The power supply system for flowing high-frequency power was fixed
In the state, each of the first electrode and the second electrode is connected to the ground.
Switch that can be selectively connected as a DC circuit (high frequency
In terms of an AC circuit, a choke coil is added in series.
The connection between the first electrode and the second electrode is disabled.
Switch to switch the potential of each electrode
By setting it to earth potential or floating potential,
Configuration of the coupling or anode coupling
It can be realized.

In the above configuration, preferably, the ground circuit is a choke coil.

In the above configuration, preferably, the variable capacitor of the variable reactance circuit comprises a coarse adjustment capacitor and a fine adjustment capacitor.

In the above configuration, preferably, a coupling capacitor is connected between the first electrode and the matching circuit.

[0011]

According to the present invention, a series circuit of a switch and a choke coil is arranged between each of the two electrodes and the ground, and the first and second switches are turned on and off as appropriate. Can be arbitrarily held at the ground potential as a DC circuit, can be cut off against high frequency, and is disposed at a position facing the first electrode to which high frequency power is applied. Since a reactance variable circuit including a series circuit including a coil and a variable capacitor is connected between the second electrode and the ground, the reactance between the electrode and the ground can be reduced to zero.

That is, in the same configuration as the high-frequency circuit, each electrode can be set to either the ground potential or the floating potential. As a result, with respect to the substrate mounted on the second electrode, a cathode coupling configuration in which the first electrode is set to the ground potential and the second electrode is set to the floating potential, and conversely, the second electrode is set to the ground potential, The configuration of the anode coupling with the electrode at the floating potential can be arbitrarily and easily switched.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows the configuration of a parallel plate type plasma processing apparatus. In this figure, reference numeral 1 denotes a container forming a processing chamber. When performing the plasma processing inside the container 1, a required vacuum state is created. The container 1 is formed of a conductive member. Inside the container 1, a first electrode (for example, a cathode electrode) 2 is disposed on the upper side, and a second electrode (for example, an anode electrode) 3 is disposed on the lower side. The container 1 is electrically connected to the ground and is kept at the ground potential (zero potential). The electrode 2 and the electrode 3 are arranged in a positional relationship facing each other in the container 1.

A predetermined internal space is formed in the electrode 2, and this space is connected to the gas introducing section 4. Gas inlet 4
Is provided with a gas supply mechanism for accommodating a required source gas. On the processing chamber side of the electrode 2, a wall 2a having a large number of pores 2b is provided, and the source gas introduced through these pores 2b is supplied into the processing chamber. The source gas is blown out into the space between the electrode 2 and the electrode 3 in a uniform state. In FIG. 1, an arrow A indicates the state of blowing of the source gas.

On the electrode 3, a substrate 5 to be processed is placed. The electrode 3 is provided with a cooling mechanism 6 for circulating cooling water in the internal space.

A high frequency power supply 9 is connected to the electrode 2 via a matching circuit 7 and a coupling capacitor 8. The matching circuit 7, the coupling capacitor 8, and the high frequency power supply 9 are provided outside the container 1. The other connection end of the high frequency power supply 9 is connected to the ground. Further, a choke coil 11a is connected between the electrode 2 and the ground via a switch 10a. The high-frequency power supply 9 supplies high-frequency power, which is the output thereof, to the processing chamber in the container 1 and generates plasma in the processing chamber using the high-frequency power.

A variable reactance circuit 12 is connected between the electrode 3 and the ground. This reactance variable circuit 1
2 includes a variable element that makes it possible to change the magnitude of its reactance. Specifically, the variable reactance circuit 12 is configured as a series circuit of a coil 13 and a variable capacitor 14. The coil 13 can be actually connected as a coil as an electric circuit element, or can be equivalently formed as an inductance element using a member such as a copper plate. In short, it is only necessary that the inductance element exists in the electric circuit. Coil 13, the value of the respective circuit elements of the variable capacitor 1 4 is optionally determined corresponding to each of the various plasma processing apparatus. Further, a choke coil 11b is connected between the electrode 3 and the ground via a switch 10b as in the case of the electrode 2.

The switches 10a and 10b and the choke coils 11a and 11 connected to the electrodes 2 and 3, respectively.
b is used when each electrode is grounded as a DC circuit, and a grounding circuit for DC is formed by turning on the switches 10a and 11b.

As shown in FIG. 2, the variable capacitor 14 includes a coarse adjustment capacitor 14a and a fine adjustment capacitor 14b as an example of a specific configuration.

As shown in FIG. 1, an insulator 15 is disposed at a required position in the container 1 to provide electrical insulation.

In the plasma processing apparatus, as described above, the reactance variable circuit 12, the choke coils 11a and 11b, and the switches 10a and 10b are provided at predetermined locations, so that either the anode coupling or the cathode coupling can be selected. They can be set and can be switched arbitrarily. Next, an operation relating to switching of the anode coupling or the cathode coupling will be described with reference to FIG.

The high-frequency power supplied from the electrode 2 usually passes through the plasma generated between the electrodes 2 and 3 and flows to the ground through both the electrode 3 and the wall of the container 1.
At this time, the plasma 16 is applied to the electrodes 2 and 3 in the vessel 1.
And the inner surface of the wall of the container 1. In this state,
By adjusting the high-frequency reactance value of the reactance variable circuit 12 and setting the impedance to an appropriate value with respect to the high frequency supplied from the high-frequency power supply 9, the high-frequency power can be appropriately distributed to the electrode 3 and the wall of the container 1. it can. In this case, the potential of the electrode which is in contact with the plasma 16 and has a floating potential in a DC circuit is determined by the ratio of the area of the portion holding the floating potential to the area of the portion holding the ground potential. The floating potential becomes a positive potential when its area is larger than the area of the ground potential part, and becomes a negative potential when it is smaller. In FIG. 1 or FIG.
When the switch 10a connected to the electrode 3 is turned on and the switch 10b connected to the electrode 3 is turned off, as shown in FIG. 4, the potential of the electrode 3 on which the substrate 5 is mounted becomes negative, and the potential of the electrode 2 becomes 0 (cathode coupling). Conversely, when the switch 10a connected to the electrode 2 is turned off and the switch 10b connected to the electrode 3 is turned on, the potential of the electrode 3 on which the substrate 5 is mounted becomes 0 as shown in FIG. The electrode 2 has a negative potential (anode coupling). Thus, by switching the connection state of the switches 10a and 10b, the anode coupling and the cathode coupling can be arbitrarily switched in the power supply system of the plasma processing apparatus. In this manner, the anode coupling and the cathode coupling can be switched by turning on / off the switches 10a and 10b attached to the respective electrodes 2 and 3, so that automation can be supported.

In the above operation, the bias voltage generated at the floating electrode is determined depending on various conditions of the used plasma processing apparatus.

The plasma processing apparatus having the power supply system described above can be applied to, for example, a thin film forming apparatus and an etching apparatus.

[0026]

As is apparent from the above description, according to the present invention, a switch enabling grounding via a choke coil to each of two plate electrodes provided in parallel in a plasma processing apparatus, and A variable reactance circuit is provided between the other electrode facing the high-frequency application electrode and the earth, so that the electrode to be grounded can be arbitrarily switched as a DC circuit, and the anode coupling and the cathode coupling can be easily changed arbitrarily. Can be switched. In addition, since the configuration can cope with automation, the switching operation can be automatically performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a plasma processing apparatus according to the present invention.

FIG. 2 is a circuit diagram showing another embodiment of the variable reactance circuit.

FIG. 3 is a circuit configuration diagram of a power supply system when plasma is generated in the plasma processing apparatus.

FIG. 4 is a distribution diagram showing a first distribution state of plasma.

FIG. 5 is a distribution diagram showing a second distribution state of plasma.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Container 2, 3 electrode 5 Substrate 7 Matching circuit 8 Coupling coil 9 High frequency power supply 10a, 10b Switch 11a, 11b Choke coil 12 Reactance variable circuit

Claims (3)

(57) [Claims] 1. A container, first and second electrodes arranged in a positional relationship facing each other inside the container, a gas supply mechanism for supplying a gas into the container, and the first electrode
A high-frequency power supply that supplies high-frequency power between the second electrodes ;
And a board installed on the second electrode, the first
In a plasma processing apparatus for processing a substrate by generating plasma between an electrode and the second electrode , the high-frequency power source is fixed to the first electrode via a matching circuit.
A choke coil is provided between each of the first electrode and the second electrode and the ground via a switch, and a second electrode is further provided between the second electrode and the ground.
Reactance is possible to prevent the pole from being DC grounded
A variable circuit, and this reactance variable circuit
And a variable capacitor.
Characteristics from capacitive to inductive by adjusting the sensor
And the switch on the first electrode side is connected and
Disconnecting the switch on the second electrode side
And the first electrode side
In a non-connected state and the second electrode side
By connecting the switch, the anode coupling
A plasma processing apparatus characterized in that the plasma processing apparatus uses a plasma processing method . 2. The plasma device according to claim 1, wherein
The variable capacitor of the reactance variable circuit is
A plasma processing apparatus comprising an adjustment capacitor and a fine adjustment capacitor . 3. The plasma processing apparatus according to claim 1 , wherein a coupling is provided between the first electrode and the matching circuit.
A plasma processing apparatus to which a capacitor is connected .