JPH01139762A - Sputtering apparatus - Google Patents

Abstract

PURPOSE:To stably operate a microwave radiating means even when a sputtered material is deposited by providing a magnetic field impressing means and the microwave radiating means in a vacuum vessel, and using a helical coil connected to a microwave source as the radiating means. CONSTITUTION:Gaseous Ar is introduced into the vacuum vessel 1 from an inlet 2, a microwave is led to the helical coil 9 from a microwave power source 11, and a bias voltage at about +200V is impressed on the helical coil 9 from a bias voltage impressing device 10. At this time, the magnetic field of a permanent magnet 12 is set to cause electron cyclotron resonance on the helical coil 9, and hence a high-density plasma is produced in the helical coil 9. When a high-frequency power is impressed on a target 4 under such conditions, the ion generated by the microwave electron cyclotron resonance discharge hits the target 4, hence the target is sputtered, the sputtered material is deposited and accumulated on a substrate 7, and a thin film is formed. At this time, the plasma diffusing toward the substrate 7 from a multicusp magnetic field is confined by the parallel magnetic field of a permanent magnet 13, and the film forming rate is increased.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a sputtering apparatus for forming a thin film on a substrate by sputtering in semiconductor processing technology, surface treatment technology, etc., and particularly for realizing high-speed thin film formation. This invention relates to a sputtering device.

BACKGROUND OF THE INVENTION At present, thin films sputtered by magnetron sputtering are widely used industrially. In particular, high-frequency magnetron sputtering using high-frequency discharge is common in forming dielectric films. However, as the demand for dielectric films such as optical thin films and ferroelectric films is rapidly increasing, efforts are required to improve productivity by increasing the thin film forming speed of high-frequency magnetology battering, which has a slow thin film forming speed. There is.

Therefore, in order to improve the sputtering film formation speed,
One possible method is to cover the target surface with high-density plasma using a magnetic field application device and microwave oscillation, increase the ion bombardment current density on the target, and increase the number of particles sputtered from the target.

An example of a technology that adopts this idea is JP-A-61-6
There is one described in Publication No. 0881. The outline of this sputtering apparatus will be explained with reference to FIG. 2. The vacuum chamber 16 can be evacuated and has a gas inlet 1γ for introducing discharge sustaining gas, and a gas inlet 1γ on the opposite side from the gas inlet 1γ. A microwave source 20 (for example, a magnetron with a frequency of 2.45 GHz) is supplied through a plasma generation chamber 18 provided therein.
is connected, and microwave power is supplied from this microwave source 2o through a micro window 19 made of S z O2 glass. A sputtering target 22 is attached to a target holder 21 provided in the vacuum chamber 16, and these are separated from the vacuum chamber 16 by an insulating insulator 2.
3 and is electrically insulated. Also, inside the target holder 21, there is a magnet coil 25 for obtaining a magnetic field that causes electron cyclotron resonance for microwaves.
is installed. High frequency power can be applied to the target holder 21 and the sputtering target 22 from a high frequency power supply 26 . 27 is target holder 21
A substrate 28 to be sputtered is mounted 9 on a substrate holder disposed opposite to the substrate holder. Still, board holder 2
Inside of 7, a magnetic carp 1V29 is installed.

In such a structure, a discharge sustaining gas such as argon is introduced through the gas inlet 17.

Microwave power is supplied from the microwave source 2o to the plasma generation chamber 18 through the microwave window 19. At this time, the directions of the magnetic lines of force formed by the magnet coil/L/25.29 placed on the back surface of the sputtering target 22 and the substrate 28 are opposite to each other, and the magnetic field strength is set so that electron cyclotron resonance occurs (for example, 2 ．．
876 Gauss for a frequency of 45GH2) Then,
A high-density plasma is generated.

When high frequency power is supplied to the sputtering target 22 from the high frequency power supply 26, ions generated by microwave electron cyclotron resonance strike the sputtering target 22, and the material is sputtered. The target material released by sputtering adheres and deposits on the substrate 28 to form a thin film.

Problems to be Solved by the Invention However, the above configuration has the disadvantage that when a conductive sputtering target is used, sputtered matter adheres to the microwave window, making it impossible to supply microwave power to the plasma generation chamber. have. Furthermore, since a magnet coil inside the vacuum container is used as the magnetic field applying means, there is also a drawback that the vacuum container apparatus becomes large and complicated.

Means for Solving the Problems The first aspect of the present invention is to solve the above-mentioned problems of the conventional art. In a sputtering apparatus that performs sputtering processing by having a cathode to be placed, a power source for applying a voltage to the cathode, and a substrate to be processed facing the target at a predetermined distance, a vacuum container is placed in the vacuum container. It is characterized by comprising a magnetic field applying means for applying a magnetic field from the outside and a microwave emitting means for emitting microwaves into the vacuum container, and a helical coil connected to a microwave source is used as the microwave emitting means. It is something to do.

Moreover, the second aspect of the present invention. Each of the third inventions aims to solve the above-mentioned conventional problems and to make it possible to form a thin film more advantageously. Sputtering is performed using a target as a film formation source, a cathode on which the target is placed, a power source that applies voltage to the cathode, and a substrate to be processed that faces the target at a predetermined distance. The sputtering apparatus includes a magnetic field applying means for applying a magnetic field into the vacuum container from outside the vacuum container, and a microwave radiation means for radiating microwaves into the vacuum container using a helical coil connected to a microwave source. , the magnetic field applying means is applied to the front surface of the substrate to be processed in a direction parallel to the substrate.
It is characterized in that it forms a magnetic field of less than Gauss.

Still, a third invention includes a target as a film forming source made of a material to be sputtered in a vacuum container, a cathode on which the target is placed, a power source for applying a voltage to the cathode, and a target separated from the target by a predetermined distance. In a sputtering apparatus that performs sputtering processing by having a substrate to be processed facing each other,
A magnetic field applying means for applying a magnetic field into the vacuum container from outside the vacuum container, and a microwave emitting means for emitting microwaves into the vacuum container using a helical coil connected to a microwave source, +2 to wave radiation means
It is characterized in that a bias voltage of 00V or less is applied.

Operation According to the first aspect of the present invention, due to the above-mentioned configuration, the microwave radiating means is operated by a helical coil located in the vacuum chamber, so that it operates stably even if sputtered matter is attached. Since the multi-cusp magnetic field used for plasma confinement is composed of permanent magnets, etc. outside the vacuum vessel, the vacuum vessel apparatus becomes smaller.

The second aspect of the present invention is that, due to the above structure, electrons flowing into the substrate to be processed are exposed to a parallel magnetic field of 200 Gauss or less parallel to the front side of the substrate, which is formed by a magnetic field applying means such as a permanent magnet outside the vacuum container. It is trapped and prevented from flowing into the substrate, thereby preventing temperature rise and damage to the substrate to be processed. Also,
The plasma confinement efficiency increases, and the plasma density, that is, the sputtering film formation rate increases.

In the third aspect of the present invention, since a bias voltage of +200 V or less is applied to the microwave emitting means due to the above-mentioned configuration, there is no spatter from the helical coil provided in the vacuum container which is the action part of the microwave emitting means. Continuous operation for a long time is possible, and impurities are not mixed into the thin film formed on the substrate to be processed.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIG.

In FIG. 1, a gas inlet for introducing discharge sustaining gas into a vacuum chamber 1 that can be evacuated is provided on one side, a target holder 3 is located at the bottom, and a substrate holder 6 is located at the top, facing each other vertically. A sputtering target 4 is attached to the target holder 3, and the sputtering target 4 is electrically insulated from the vacuum chamber 1 by an insulating insulator 5 between the target holder 3 and the vacuum chamber 1. A substrate 7 to be sputtered is attached to the substrate holder 6 .

There is a microwave inlet 8 on the bottom side of the vacuum chamber 1, a helical coil 9 is connected to the inside thereof, and a microwave source 11 is connected to the outer core through a bias voltage applying device 10 via a coaxial line. 1 and 4 are connected.

Further, a permanent magnet 12 is installed around the outer periphery of the vacuum chamber 1 to generate an electron cyclotron resonance with microwaves and to obtain a multi-cusp magnetic field to confine plasma. Further, a permanent magnet 13 is installed in parallel with the substrate 7 on the front surface of the substrate holder 6 to generate a magnetic field of 200 Gauss or less.

In such a structure, first, a discharge sustaining gas such as argon is introduced into the vacuum chamber 1 through the gas inlet 2. Then microwave source 10 (e.g. frequency 2, 4
Microwaves from a 5 GHz magnetron are guided to the helical coil IV9 through the coaxial line 14 and the microwave inlet 8 in sequence. Also, in Herikarkoi/L/9,
A bias voltage of +200V is applied by the bias voltage application device 10. At this time, if the magnetic field of the permanent magnet 12 is set to create electron cyclotron resonance on the helical coil 9 (for example, 876 Gauss for a frequency of 2.45 GHz), high-density plasma is generated within the helical coil e. be done.

If high frequency power is applied from the high frequency power source 16 to the sputtering target 4 attached to the target holder 3 in this state, ions generated by the microwave electron cyclotron resonance discharge will strike the sputtering target 4 and sputter the material. let The target material released by sputtering adheres and deposits on the substrate 7 to form a thin film.

The parallel magnetic field formed by the permanent magnet 13 confines plasma that diffuses toward the substrate 7 from the multicusp magnetic field by the permanent magnet 12, prevents electrons from flowing into the substrate 7, and prevents substrate temperature rise and element damage. Furthermore, the plasma confinement efficiency is improved, the plasma density of the plasma confined by the multicusp magnetic field and the parallel magnetic field is increased, and the sputtering film formation rate is improved.

In addition, a voltage of 9+2 ooV is applied to the helical coil L'9 by a bias voltage application device to prevent sputtering of the helical coil 9 by ions in the plasma.
Enables continuous operation for long periods of time.

In addition, contamination of the helical coil material by sputtering into the formed thin film on the substrate γ is eliminated, and the purity of the formed thin film is improved.

Further, in this embodiment, instead of using the coaxial line 14, a waveguide may be used to achieve the same effect.

Effects of the Invention As described above, each of the first, second, and third inventions of the present invention has the above-described configuration and operation. According to the first invention, the helical coil for microwave radiation is Since it is located inside a chamber, it operates stably even if sputtered matter adheres to it, and the use of permanent magnets allows the device to be miniaturized, which has great effects.

Further, according to the second aspect of the invention, it is possible to prevent electrons from flowing into the substrate to be processed, thereby preventing a rise in substrate temperature and damage to elements.

Furthermore, according to the third aspect of the present invention, sputtering of the helical coil for microwave radiation is eliminated, allowing continuous operation for a long time, and contamination of impurities into the thin film formed on the substrate to be processed can be eliminated. can.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a sputtering apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional sputtering apparatus. 1... Vacuum chamber, 3... Target holder, 4... Sputtering target,
6... Board holder, 7... Board, 8...
...Microwave inlet, 9...Helical coil, 1o...Bias voltage application device, 11
......Microwave source, 12.13...Permanent magnet. Name of agent: Patent attorney Toshio Nakao and 1 other person 4-
-°Suhazotaringe target 1 r---4 extraction + rt router 1 7---

Claims (1)

[Claims] (1) A target as a film forming source made of a material to be sputtered in a vacuum container, and a cathode on which this target is placed;
In a sputtering apparatus that performs sputtering by having a power supply that applies voltage to the cathode and a substrate to be processed facing the target at a predetermined distance, a magnetic field is applied into the vacuum container from outside the vacuum container. a magnetic field applying means;
A sputtering apparatus comprising a microwave radiating means for radiating microwaves into the vacuum container, and using a helical coil connected to a microwave source as the microwave radiating means. (2) The sputtering apparatus according to claim 1, wherein the magnetic field applying means supplies a magnetic field satisfying electron cyclotron resonance to the microwave emitting means. (3) The sputtering apparatus according to claim 1, wherein the helical coil is disposed in front of the target, and the magnetic field formed by the magnetic field applying means forms a cusp magnetic field. (4) a target as a film forming source made of a material to be sputtered in a vacuum container, and a cathode on which this target is placed;
In a sputtering apparatus that performs sputtering and has a power supply that applies voltage to the cathode and a substrate to be processed that faces the target at a predetermined distance, a magnetic field is applied into the vacuum container from outside the vacuum container. a magnetic field applying means;
microwave radiating means for radiating microwaves into a vacuum container using a helical coil connected to a microwave source; Sputtering equipment for forming. (5) a target as a film forming source made of a material to be sputtered in a vacuum container, and a cathode on which this target is placed;
In a sputtering apparatus that performs sputtering and has a power supply that applies voltage to the cathode and a substrate to be processed that faces the target at a predetermined distance, a magnetic field is applied into the vacuum container from outside the vacuum container. a magnetic field applying means;
A sputtering apparatus comprising a microwave radiating means in the vacuum container using a helical coil connected to a microwave source, and applying a bias voltage of +200V or less to the microwave radiating means.