JP2001049429A - Reactive sputtering method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactive sputtering apparatus and a method thereof capable of forming a thin film in which a target atom and a reactive gas have sufficiently reacted on a surface of a substrate without lowering a film forming rate. I do. SOLUTION: While introducing a discharge gas into a vacuum chamber 1, a voltage is applied between both electrodes of a target 3 and a substrate 2 to generate a glow discharge. Is ionized and supplied from the vicinity of the substrate 2 to react with target atoms to form a thin film on the surface of the substrate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for producing a glow discharge by applying a voltage between both electrodes of a target and a substrate while introducing a discharge gas into a vacuum chamber, and repelling target atoms from the target. The present invention relates to a reactive sputtering method for forming a thin film on the surface of a substrate by reacting target atoms with a reactive gas introduced from the outside, and an apparatus therefor.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional reactive sputtering apparatus. A substrate 2 for forming a thin film serving as an electrode is disposed inside the vacuum chamber 1, and a target 3 serving as an electrode is disposed above the vacuum chamber 1 facing the surface of the substrate 2. A discharge gas inlet 4 for introducing a discharge gas from the outside is formed on one wall of the vacuum chamber 1 with the substrate 2 interposed therebetween, and on the lower side of the opposite wall, A reactive gas inlet 5 for introducing a reactive gas is provided. 6 is an exhaust port.

[0003] As the reactive gas, such as oxygen or nitrogen is used as the target material, such as metal or Al ₂ 0 ₃ derivatives such as such as Al or Cu is used,
Ar or the like is used as the discharge gas. When the discharge gas is introduced into the vacuum chamber 1, power is supplied to the target 3 by a high-voltage power supply 7 for glow discharge provided outside the vacuum chamber 1, and high-density plasma for sputtering is generated. At this time, if a magnetron magnet 8 that generates lines of magnetic force that closes on the front surface of the target 3 is disposed on the back surface of the target 3, higher-density plasma can be generated to form a film at high speed.

When the ions in the generated plasma hit the surface of the target 3, the target atoms are sputtered and adhere to the surface of the substrate 2. At the same time, a reactive gas is introduced from the reactive gas inlet 5, and the reactive gas reacts with target atoms to form a thin film made of a compound on the surface of the substrate 2. Note that the composition ratio of the compound formed on the surface of the substrate 2 is determined by the flow rate of the reactive gas.

[0005] The target atoms sputtered are
Not only the surface of the substrate 2 and the surface of the target 3 but also the vacuum chamber 1
Is dispersed everywhere inside and reacts with the reactive gas to form a compound.

[0006]

In the reactive sputtering apparatus as described above, when a compound in which a target atom and a reactive gas have sufficiently reacted with each other is grown on the surface of the substrate 2, the flow rate of the reactive gas is reduced. More is needed.
However, the reaction between the reactive gas and the target atom is
As described above, since the reaction occurs everywhere in the vacuum chamber 1, if the flow rate of the reactive gas is increased, the reaction between the reactive gas and the target atoms proceeds on the surface of the target 3. In addition, since the compound after the reaction generally has a lower sputtering rate, the film formation rate on the surface of the substrate 2 is rapidly reduced as the reaction on the surface of the target 3 proceeds.

The present invention solves the above problems and provides a reactive sputtering method capable of forming a thin film in which target atoms and a reactive gas have sufficiently reacted on the surface of a substrate without reducing a film forming rate. It is intended to provide the device.

[0008]

The reactive sputtering apparatus according to the present invention is characterized in that the reactive gas supply means is special. According to this invention, since the target atoms and the reactive gas can be sufficiently reacted only on the substrate side, the compound of the target atoms and the reactive gas can be formed on the surface of the substrate without lowering the film forming rate. A thin film can be formed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a reactive sputtering apparatus according to the present invention, a glow discharge is generated by applying a voltage between both electrodes of a target and a substrate while introducing a discharge gas into a vacuum chamber. A reactive sputtering apparatus for repelling target atoms from the target and reacting the target atoms with a reactive gas introduced from the outside to form a thin film on the surface of the substrate, wherein the reactive gas is ionized to form a thin film. It is characterized in that a means for supplying from the vicinity of the substrate and reacting with the target atoms is provided.

According to this structure, since the reactive gas is ionized, the reaction with the target atoms on the substrate surface is promoted, and the reactive gas is supplied from the vicinity of the substrate so that the reactive gas is ionized. Since the reaction with the reactive gas can be suppressed, a thin film that has sufficiently reacted can be formed on the surface of the substrate without lowering the deposition rate.

A reactive sputtering apparatus according to a second aspect of the present invention is characterized in that, in the first aspect, means for changing a potential of the substrate is provided. According to this configuration,
By changing the potential of the substrate, the ionized reactive gas is easily attracted to the substrate, and the rate of incidence of the reactive gas on the substrate can be adjusted, so that the reaction on the surface of the substrate can be more effectively performed. Can be promoted.

In the reactive sputtering method according to a third aspect of the present invention, a glow discharge is generated by applying a voltage between both electrodes of a target and a substrate while introducing a discharge gas into a vacuum chamber. In addition to repelling target atoms, a reactive gas is ionized and supplied from the vicinity of the substrate to react with the target atoms to form a thin film on the surface of the substrate.

[0013] According to this configuration, since the reactive gas ionized and the target atom can be reacted in the vicinity of the substrate, the target atom and the reactive gas can be efficiently reacted, and the film forming speed can be reduced. A thin film can be formed on the surface of the substrate without lowering. Hereinafter, a reactive sputtering method using the reactive sputtering apparatus of the present invention will be described based on specific embodiments.

The same components as those shown in FIG. 5 showing the conventional example are denoted by the same reference numerals. FIG.
Shows a sputtering apparatus of the present invention. This embodiment is different from the conventional reactive sputtering apparatus in that the reactive gas supply means is specially controlled in order to suppress a decrease in the film formation rate. This is the same as FIG.

An Al target 3 and a substrate 2 are arranged inside a vacuum chamber 1 so as to face each other. On both sides of the substrate 2, reactive gas introduction ports 5a and 5b extending from the lower side of the vacuum chamber 1 are provided as means for ionizing the reactive gas and supplying it from the vicinity of the substrate to react with target atoms. Waveguides 9a and 9b for extending microwaves from the outside of the vacuum chamber 1 connected to the outlets of the reactive gas introduction pipes 5a and 5b and having outlets extending to the vicinity of the substrate 2, and waveguides 9a and 9b.
A pair of ECR electromagnets 12a to 12d are provided at the outlet of 9b.

Using the reactive sputtering apparatus configured as described above, oxygen is used as a reactive gas, Al is used as a target, and Ar is used as a discharge gas.
Glow discharge occurs when a voltage is applied between the substrate 2 and the target 3 by applying power to the Al target 3 by the high voltage power supply 7 while introducing Ar gas from the discharge gas inlet 4 into the vacuum chamber 1. Is generated and plasma is generated.

Ar ions in the plasma are accelerated and collide with the target 3, and Al atoms fly out and adhere to the surface of the substrate 2. At the same time, when a current is supplied to the ECR electromagnets 12a to 12d to generate a magnetic field and a microwave is supplied to the waveguides 9a and 9b, ECR plasma is generated and oxygen gas is ionized.

Since the reaction efficiency of the ionized oxygen gas with the target atoms is improved, the surface of the substrate 2 is made of Al ₂ gas.
A thin film made of O ₃ is formed efficiently. Further, since the gas is supplied from the outlet extending to the vicinity of the substrate 2 as described above, the ionized oxygen gas hardly reaches the vicinity of the surface of the target 3 than before, and the compound is formed on the surface of the target 3. Substrate 2 by being done
Of the film forming rate on the surface of the substrate can be reduced.

As a result, without increasing the flow rate of oxygen,
In addition, an Al ₂ O ₃ thin film can be formed on the surface of the substrate 2 without lowering the film forming speed. In addition to the above configuration, a means for changing the potential of the substrate 2 may be provided. Here, a bias power source 10 is connected to the substrate 2 to change the potential applied to the substrate 2 when the ionized oxygen reacts with the target atoms.

With such a configuration, the ionized oxygen gas is easily attracted to the substrate 2 and the incident angle of the oxygen gas to the substrate 2 can be adjusted.
The oxidation reaction on the surface of the substrate 2 can be more effectively promoted.
In the above-described embodiment, the discharge ports of the waveguides 9a and 9b and the ECR electromagnets 12a to 12d that generate a magnetic field are disposed so as to be parallel to the substrate 2, respectively. As described above, the same effect can be obtained by disposing the discharge ports of the waveguides 9a and 9b and the ECR electromagnets 12a to 12d which generate the magnetic field so as to be perpendicular to the substrate 2, respectively.

However, in such a configuration, the waveguides 9a, 9a,
Since the outlet of 9b is open on the side of the target 3, it is preferable to dispose the deposition prevention plate 11 above the inlets 9a and 9b in order to prevent the deposition of sputtered target atoms. Further, in the above embodiment, when the reactive gas is ionized, the ionization is performed by the ECR method. However, the present invention is not limited to this. For example, as shown in FIG. , 5f, and inductive coupling coils 13a, 13b arranged in parallel on both sides of the substrate 2 and coil power supplies 14a,
14b may be arranged, and high-frequency application inductively coupled to the introduced reactive gas may be applied for ionization. Alternatively, as shown in FIG. 4, inductive coupling coils 13c and 13d vertically arranged on both sides of the substrate 2 and coil power sources 14c and 14c connected to the reactive gas introduction ports 5g and 5h near the exhaust ports.
14d may be arranged, and high-frequency application inductively coupled to the introduced reactive gas may be applied to perform ionization.

In addition, it can be realized by various methods such as a method of generating a helicon wave to ionize a reactive gas. In the above description, an example is shown in which a pair of ECR electromagnets 12a to 12e, inductive coupling coils 13a to 13d, and the like are arranged at the exhaust ports of the reactive gas introduction ports 5a to 5h.
The present invention is not limited to this, and the ECR electromagnets 12a to 12e, the inductive coupling coils 13a to 13d, and the like may be arranged around the substrate 2, and the installation places may be arranged at one or more places. May be. More preferably, it is preferable to provide a plurality of them around the substrate 2 so that the angles are evenly distributed.

In each of the above embodiments, the gas supplied from the reactive gas inlets 5a to 5h may be only oxygen, but when the oxygen flow rate is small, the discharge gas inlet 4
The flow rate of Ar introduced from the gas is increased, or the flow rate of Ar introduced from the discharge gas introduction port 4 is reduced, and the Ar gas is simultaneously supplied with oxygen gas from the reactive gas introduction ports 5a to 5h by the reduced amount. , The discharge is easily maintained.

In the above description, a high-frequency power supply is used as the high-voltage power supply 7 for supplying power to the back surface of the target 3, but a DC power supply may be used. Further, in the above description,
Although an example in which oxygen is used as a reactive gas, Al is used as a target, and Ar is used as a discharge gas, the present invention is not limited to this. What is used is used.

[0025]

As described above, according to the reactive sputtering apparatus of the present invention, a means for ionizing a reactive gas and supplying the ionized gas from the vicinity of the substrate to react with target atoms is provided. Since only the reaction between the target atoms and the reactive gas in the step is promoted, a thin film can be formed on the surface of the substrate without lowering the film formation rate.

Further, by providing a means for changing the potential of the substrate, the ionized reactive gas is easily attracted to the substrate, and the rate of incidence of the reactive gas on the substrate can be adjusted. The reaction on the surface can be promoted.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a reactive sputtering apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a reactive sputtering device in which coils arranged in the opposite direction to the embodiment of the present invention are arranged.

FIG. 3 is a configuration diagram of a reactive sputtering apparatus provided with a high-frequency device as another ionization means different from the embodiment of the present invention.

FIG. 4 is a configuration diagram of a reactive sputtering apparatus provided with a device for generating a helicon wave as another ionization means different from the embodiment of the present invention.

FIG. 5 is a configuration diagram of a conventional reactive sputtering apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum tank 2 Substrate 3 Target 4 Discharge gas introduction port 5a-5h Reactive gas introduction port 9a-9d Waveguide 10 Power supply for bias 11 Deposition plate 12a-12d Electromagnet for ECR 13a-13d Inductive coupling coil 14a-14d Coil Power supply

Claims (3)

[Claims] A glow discharge is generated by applying a voltage between both electrodes of a target and a substrate while introducing a discharge gas into a vacuum chamber, and repels target atoms from the target to introduce the target atoms from the outside. A reactive sputtering apparatus for forming a thin film on the surface of the substrate by reacting with the reactive gas, wherein a means for ionizing the reactive gas and supplying it from the vicinity of the substrate to react with target atoms is provided. Reactive sputtering equipment. 2. The reactive sputtering apparatus according to claim 1, further comprising means for changing a potential of the substrate. 3. A glow discharge is generated by applying a voltage between both electrodes of a target and a substrate while introducing a discharge gas into a vacuum chamber, thereby repelling target atoms from the target and ionizing a reactive gas. Reactive sputtering method for forming a thin film on the surface of the substrate by supplying from the vicinity of the substrate and reacting with target atoms.