JPH06325711A - Spatter type ion source - Google Patents

Abstract

PURPOSE:To realize an automatic regeneration of an arc discharge by providing an arc discharge stabilizing electrode near a spatter target. CONSTITUTION:When an operating gas is led in a plasma chamber 1 as well as a filamant F14 is heated, a current flows from a power source Varc for arc discharge to arc discharge stabilizing electrodes 17 and 18 through a resistor R at the starting so as to operate them as anodes, an arc discharge is generated between the filamant F14 and the electrodes 17 and 18, and a plasma is generated in the chamber 10. Also an arc discharge is generated between an anode 10a and the filamant F14. When the plasma is extinguished in the chamber 10, a current flows from the power source Varc to the electrodes 17 and 18 so as to operate them as anodes, an arc discharge is generated between the filamant F14 and the electrodes 17 and 18, and a plasma is generated in the chamber 10. Consequently, it is not necessary to generate a plasma by an operator at the starting, and since the arc discharge is generated automatically even though the arc discharge is stopped, the plasma can be generated stably constantly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputter type ion source used for surface layer modification, surface layer treatment and thin film forming apparatus.

[0002]

2. Description of the Related Art When an ion beam hits a workpiece, the induced energy of the ion beam changes to thermal energy.
Since it dissolves and evaporates on the surface of the object to be processed, it is used for processing the object to be processed such as induction, polishing, etching, and surface treatment. In recent years, it has been used for manufacturing ICs, implanting impurities into semiconductors, and oxide films. It is used in the surface treatment such as the production of metal and nitride, and in the production of thin films.

An ion source is known as a device for obtaining this ion beam, and the ion source is constructed so that a plasma is generated in a plasma generation chamber, only ions of the plasma are taken out, and accelerated by a high voltage to produce an ion beam. There is an ion source for exclusive use of gas ions and an ion source of a type in which a substance such as a metal in a crucible is evaporated and turned into plasma in a plasma generation chamber.

FIG. 2 is a sectional view showing an example of a currently proposed sputter type ion source.

In the figure, reference numeral 1 denotes a plasma chamber formed by a cylindrical wall 1a which serves as an anode electrode. A beam extraction electrode 2 is provided on the front surface (lower side of the figure) of the plasma chamber and rearward (upper side of the figure). Is provided with a working gas introduction part 3. A filament 4 serving as a cathode is provided behind the plasma chamber 1, and the filament 4 and the beam extraction electrode 2 are provided.
Between them and the sputtering targets 5 and 6 which are perpendicular to the beam extraction electrode 2 and face each other, a negative high voltage (not shown) is applied.

When the working gas is introduced into the plasma chamber 1, the working gas is turned into plasma by arc discharge between the filament 4 and the anode electrode 1a. Further, by applying a negative high voltage to the sputter targets 5 and 6, the sputter material constituent atoms are emitted by the sputtering action. These atoms are ionized in the plasma chamber 1 and extracted as an ion beam from the beam extraction electrode 2. At this time, the atoms 7 that have not been ionized in the plasma chamber 1 adhere to the opposing sputtering targets 5 and 6 and are reused there as sputtering material. Further, when the atoms are knocked out from the sputter targets 5 and 6, secondary electrons 8 are generated, and these secondary electrons 8 are reflected by the potential barriers of the opposing sputter targets 5 and 6 and contribute to ionization. Since the electron beam does not enter the extraction electrode 2, its deformation or the like is prevented.

[0007]

By the way, the above-mentioned ion source is a filament when the electric field with respect to the distance from the anode electrode 1a is linearly applied as shown in FIGS. 3 (a) and 3 (b). Although electrons are easily emitted from _No. 4 and stable arc discharge (L ₁ ) is generated, if the size of the ion source is very small and the distance between the sputter targets 5 and 6 is narrow, the sputter targets 5 and 6 are affected. Due to the high voltage of several KV, the entire space becomes negative, and arc discharge may be difficult to occur.

Therefore, in order to easily generate an arc discharge, plasma is generated before the sputtering voltage is applied to the sputtering targets 5 and 6, so that the sheath (electric field is extinguished) is performed. This utilizes the fact that electrons are easily emitted from the filament 4 if a bias voltage (sputtering voltage) is applied to the sputtering targets 5 and 6 while plasma is being generated.

However, an abnormal discharge (L ₂ ) occurs in the plasma chamber 1 while the sputtering voltage is being applied to the sputtering targets 5 and 6.
May occur. When an abnormal discharge occurs, the electric field is curved L
_As indicated by ₃ , the filament 4 does not emit electrons and the arc discharge is extinguished, which causes a problem that the operator has to restart each time. 3 is an explanatory diagram for explaining the arc discharge and the abnormal arc discharge in the ion source shown in FIG. 2, and FIG. 3 (a) is a schematic diagram of the filament, the sputter target and the anode. FIG. 3B shows the relationship between the distance and the electric field, where the horizontal axis represents the distance from the filament and the vertical axis represents the electric field.

Therefore, an object of the present invention is to solve the above-mentioned problems, and arc discharge is generated even if plasma is not generated at the time of start, and arc discharge is automatically restarted even if arc discharge is extinguished midway. It is to provide a sputter-type ion source that can be generated.

[0011]

In order to achieve the above object, the present invention provides a sputtering type ion source in which a sputtering target is provided in a plasma chamber for generating plasma so as to face each other with a filament interposed therebetween. It is provided with an arc discharge stabilizing electrode.

[0012]

According to the above structure, at the time of start, a current flows through the arc discharge stabilizing electrode to function as an anode, and an arc discharge is generated between the filament and the arc discharge stabilizing electrode. At the same time as the arc discharge is generated, no current flows through the arc discharge stabilizing electrode, and plasma is generated in the plasma chamber. When the abnormal arc discharge occurs in the plasma chamber and the plasma is extinguished, a current again flows through the arc discharge stabilization electrode and functions as an anode, and arc discharge occurs between the filament and the arc discharge stabilization electrode, causing plasma in the plasma chamber. Occurs.

[0013]

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1A is a constitutional view showing an embodiment of the sputter type ion source of the present invention, and FIG.
FIG.

In the figure, reference numeral 10 denotes a plasma chamber formed by a cylindrical wall 10a serving as an anode. Periphery of the plasma chamber 10 is surrounded by S poles and N poles alternately so as to surround the plasma chamber 10. The magnet 11 is arranged. These permanent magnets 11 are arranged so that adjacent magnets form magnetic force lines 12 as shown in the figure, and the magnetic force lines 12 improve the plasma confinement efficiency.

A beam extraction electrode (plasma grid) 13 for extracting plasmatized atoms as an ion beam is provided on the front surface of the plasma chamber 10 (the lower side of the drawing), and a working gas for introducing a working gas such as Ar is provided behind it. An introduction part (not shown) is provided.

A filament 14 serving as a cathode is provided behind the plasma chamber 10, and the filament 14 is connected to a filament power source V _f .

In the plasma chamber 10, sputter targets 15 and 16 which are substantially perpendicular to the beam extraction electrode 13 and face each other are arranged on both sides of the filament 14, and a negative DC high voltage (or DC high voltage) is provided. (Voltage + high frequency) power supply V _s is applied.

Between the sputter targets 15 and 16,
A pair of rod-shaped arc discharge stabilizing electrodes 17 and 18 are arranged on both sides of the filament 14 substantially perpendicularly to the beam extraction electrode 13, and are connected to the anode electrode via a high resistance resistor R. A power source V _arc for arc discharge is connected between the anode electrode 10 a and the filament 14. The resistance value of the resistor R is preferably several KΩ.

Next, the operation of the embodiment will be described.

When the filament 14 is heated and a working gas such as Ar is introduced into the plasma chamber 10 from the working gas inlet, the arc discharge power source V _arc is started at the time of start.
From the arc discharge stabilizing electrodes 17 and 18 via the resistor R
Current flows into the filament and functions as an anode, and the filament 1
4 and arc discharge stabilizing electrodes 17 and 18, arc discharge is generated, and plasma is generated in the plasma chamber 10.
When arc discharge is generated in the plasma chamber 10, arc discharge is generated between the anode electrode 10a and the filament 14. At this time, due to the resistor R, the current flowing through the arc discharge stabilizing electrodes 17 and 18 is sufficiently smaller than the discharge current flowing through the anode electrode.

When an abnormal arc discharge occurs in the plasma chamber 10 and the plasma is extinguished, the arc discharge power supply V is again supplied.
_arc discharge stabilizing electrode 17 from _arc through resistor R,
A current flows through 18 to function as an anode, arc discharge is generated between the filament 14 and the arc discharge stabilizing electrodes 17 and 18, and plasma is generated in the plasma chamber 10 as described above. This eliminates the need for the operator to generate plasma at the time of start, and since arc discharge is automatically generated even when arc discharge is stopped, plasma is always generated stably.

As described above, according to this embodiment, since the arc discharge stabilizing electrode connected to the anode electrode through the resistor is provided near the filament, the arc discharge can be generated without generating plasma at the start. Even if the arc discharge is generated and disappears on the way, the arc discharge can be automatically regenerated.

[0024]

In summary, according to the present invention, the following excellent effects are exhibited.

It is possible to realize a sputter type ion source capable of generating arc discharge without generating plasma at the start and automatically regenerating arc discharge even if the arc discharge is extinguished on the way. it can.

[Brief description of drawings]

FIG. 1A is a configuration diagram showing an embodiment of a sputtering type ion source of the present invention, and FIG. 1B is a plan view taken along the line AA.

FIG. 2 is a sectional view showing an example of a currently proposed sputtering type ion source.

FIG. 3 is an explanatory diagram for explaining arc discharge and abnormal arc discharge in the ion source shown in FIG.

[Explanation of symbols]

 10 Plasma Chamber 14 Filament 15 and 16 Sputter Target 17 and 18 Arc Discharge Stabilizing Electrode

Claims (1)

[Claims] 1. A plasma chamber for generating plasma,
A sputter type ion source in which a sputter target is provided so as to face each other with a filament in between, and an arc discharge stabilizing electrode is provided in the vicinity of the sputter target.