JPS61199078A - Surface treating apparatus - Google Patents

Abstract

PURPOSE:To uniformalize density distribution of plasma, by generating a specified magnetic field to one electrode, in the titled apparatus in which high frequency voltage and negative DC voltage are impressed respectively to a pair electrodes covered with insulator excluding opposed surface in a vacuum vessel. CONSTITUTION:A pair of the electrodes 12, 13 are opposed in the vacuum vessel 11 maintaining earth voltage, high frequency voltage and negative DC voltage are impressed by sources 15, 16 respectively, and the parts excluding opposed surface of both electrodes are covered with insulators 17, 18. By providing coils 19, 20 outside the vessel 11 and conducting AC to the coils, an AC mag netic field parallel to the opposed surface of the electrode 12 is generated. The gases of bombs 21-23 are introduced to the vessel 11 at a prescribed mixing ratio, on the other hand, a prescribed pressure is maintained by a vac uum pump 28. By plasma in vacuum generated by discharge, the treatments such as film piling, etching, sputtering, cleaning are applied to the substrate surface mounted on the electrode 12.

Description

Detailed Description of the Invention (Industrial Application Field) This invention generates plasma in a vacuum by electric discharge, and uses this plasma to apply r4M deposits,
This invention relates to a surface treatment device that performs treatments such as etching, sputtering, and cleaning.

(Prior Art) When treating the surface of a workpiece using plasma in a vacuum, the plasma pi degree and the processing speed are proportional. However, in a conventional two-electrode discharge system, when attempting to obtain high-enrichment plasma by increasing the power between the electrodes, the absolute value of the negative voltage of the non-grounded electrode increases, resulting in a decrease in processing efficiency and However, there was a problem in that the ion bombardment became strong and the object to be treated was seriously damaged.

Therefore, in order to obtain high-density plasma without increasing the power between the electrodes, an apparatus shown in FIG. 6 has been conventionally known.

The device shown in FIG. 6 has a pair of electrodes 2 and 3 facing each other in a vacuum container l that holds a ground potential, and one electrode 2 is connected to a high frequency power source 4, and the other electrode 3 is connected to a DC power source 5. Connected to the negative side of

The one electrode 2 has an insulating material 6 covering a portion other than the surface facing the other electrode 3, and generates a magnetic field in the direction indicated by symbol B on this electrode 2. .

Therefore, when a high frequency voltage is applied to the one electrode 2 and a negative DC voltage is applied to the other electrode 3, the electrons emitted from the one electrode 2 are transferred to the other electrode as shown by the motion line 7. Since the electrons are pushed back by the negative voltage of the electrode 3, the probability of ionization of electrons near the electrode 2 is improved. Furthermore, the magnetic field in the direction of symbol B causes the electrons to undergo pseudo-cycloid motion, thereby further improving the probability of their ionization.

Then, due to the action of the insulator 6 and the side wall of the vacuum container l,
This pseudo-cycloid interlocking is restricted or prohibited to generate plasma within a limited range. The reason why plasma is generated in such a limited range is to generate high-density plasma with small power.

(Problems to be Solved by the Present Invention) However, in this conventional device, as shown in FIG. The density distribution becomes uneven.

If the surface of the object to be treated is treated using plasma with non-uniform density distribution, there is a problem that the surface treatment itself becomes non-uniform.

An object of the present invention is to provide an apparatus that generates high-density plasma with small power and that has a uniform density distribution.

(Means for Solving the Problems) In order to achieve the above object, the present invention has a pair of electrodes facing each other in a vacuum container that maintains a ground potential, and a high frequency voltage is applied to one of the electrodes. In the surface treatment apparatus, the other electrode is configured to apply a direct current negative voltage, and a portion of the one electrode other than the surface facing the other electrode is covered with an insulating material. Means for generating an alternating or rotating magnetic field approximately parallel to the electrodes is provided.

(Action of the present invention) Plasma produced by this device is generated by the synergistic effect of the negative voltage of the other electrode and the quasi-cycloid motion caused by the magnetic field, and at the same time, by the action of an alternating magnetic field or a rotating magnetic field, The distribution of the plasma is dispersed.

(Effects of the Present Invention) Since high-density plasma is dispersed as described above, the density distribution of the plasma becomes uniform in terms of one hour.

Therefore, efficient and high-speed surface treatment becomes possible.

In addition, since plasma is generated in a limited range, the power consumption can be reduced, and the reduced power consumption reduces ion bombardment, so that the object to be processed is not damaged.

(Embodiment of the present invention) The apparatus shown in FIG. 1 includes a pair of electrodes 12, !, in a vacuum vessel II that maintains a ground potential. 3 are facing each other.

Then, one electrode 12 is connected to a high frequency power source 15 via an impedance matching circuit 14, and the other electrode 12 is connected to a high frequency power source 15 via an impedance matching circuit 14.
3 is connected to the DC power supply 16 that supplies negative voltage, and both electrodes! The portions other than the opposing surfaces 12a and 13a of 2.13 are covered with an insulator 17.1.

In this embodiment, by grounding the vacuum container 11, the vacuum container 11 ceases to function as a ground electrode.

A coil 19.20 is provided on the outside of the vacuum vessel 11, which has a pair of electrodes inside, and by passing an alternating current through the coil 19.20, an alternating magnetic field parallel to the facing surface 12a of the electrode 12 is generated. I have to.

The vacuum container 11 thus constructed has two gas cylinders connected to each other.
The gases 1 to 23 are introduced at a predetermined mixing ratio through the valve 24, the barrier pull leak 25, and the gas inlet 28, while being evacuated by the vacuum pump 28 through the valve 27, and the inside of the vacuum container 11 is is maintained at a predetermined pressure.

Thus, while placing the substrate 29 on one electrode 12,
A processing gas is introduced into the vacuum container 11. Then, by passing an alternating current through the coils 19 and 20, the facing surface 12a of the electrode 12 is
Create an alternating magnetic field parallel to . With this alternating magnetic field created, an impedance matching circuit! 4, high frequency power from a high frequency power source 15 is supplied to the electrode 12, and the other electrode 13 is supplied with a negative voltage from the DC power source 1B.

In this way, the electrons cause a pseudo-cycloid movement on the electrode 12 due to the negative bias of the electrode 13 and the magnetic field from the coils 19 and 20, but in the forward direction of this movement, the electrons move against the insulator 17. With the side wall of the vacuum container 11,
The pseudo-cycloid movement is prohibited or restricted.

However, in this embodiment, since an alternating magnetic field is generated as described above, the electrons on the electrode 12 are dispersed by the action of this alternating magnetic field. Therefore, the plasma density distribution near the electrode 12 becomes uniform when averaged over time.

Overall, high-density plasma is uniformly generated.

Vacuum container in this state! ! If the 5i02 film is etched by introducing CHF3+5% CO2 gas into the substrate 29, the etching rate becomes almost uniform at each location on the surface of the substrate 29.

Note that a thin film can be deposited on the substrate 28 placed on one of the electrodes 12 by introducing a predetermined gas used for plasma CVD into the vacuum vessel 11, but if the introduced gas and the thin film that can be deposited are An example is as follows.

SiH4+N2 +NH3→5iNa film SiH4 or Si2H6 etc.-+aeSi:H film SiH4+N20
+S +02 film Also, in this embodiment, since the plasma is dispersed, both electrodes 12,! 3 facing surface 12a,
Even if the area of 13a is not made equal, the density distribution of the plasma can be made uniform.

In the apparatus shown in FIG. 1, the plasma was dispersed by the action of an alternating magnetic field, but as shown in FIG.
3 to 5 show a means for generating this rotating magnetic field, which may be rotated in the direction of 1 to disperse the plasma.

Fig. 3 shows an example of generating a rotating magnetic field by passing a 3-way current through three symmetrical coils 31 to 33, and Fig. 4 shows an example in which two sets of coils 34, 35.3B, and 37 have a phase of 90 degrees. This is an example in which a rotating magnetic field is generated by flowing an alternating current at different angles.

Further, in FIG. 5, magnets 38 and 39 are attached to a circular member 40 made of iron, and this circular member 40 constitutes a magnetic circuit. In the case of this FIG. 5, the circular member 40
At the same time, the magnet is rotated or the electrode 12 is rotated to create a rotating magnetic field.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a schematic cross-sectional view of a device using an alternating magnetic field, Fig. 2 is a plan view showing the direction of a rotating magnetic field, and Figs. , a principle diagram showing different means for generating a rotating magnetic field, and FIG. 6 a schematic cross-sectional view of a conventional device. 11... Vacuum container, 12... One electrode, 13...
- Other electrode, 14... High frequency power supply, 16... DC power supply, 17.18... Insulator.

Claims (1)

[Claims] A pair of electrodes are placed opposite each other in a vacuum container holding a ground potential, and a high frequency voltage is applied to one electrode, and a negative direct current voltage is applied to the other electrode. A surface treatment device comprising a surface treatment device in which a portion other than the surface facing the other electrode is covered with an insulating material, the surface treatment comprising a means for generating an alternating magnetic field or a rotating magnetic field substantially parallel to the one electrode. Device.