JPH1161400A - Sputtering method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of abnormal discharge on a target in dielectric film forming to increase discharge power and to increase the film forming rate. SOLUTION: This sputtering method is the one in which a target 2 and a substrate are oppositely arranged in a vacuum vessel, a rare gas and a reactive gas are introduced into the vacuum vessel from a gas introducing port 13, while plasma is generated, a magnet 7 arranged on the back face of the target is moved, and a compd. of the material in the target 2 and the reactive gas is coating-formed on the substrate. In this case, in accordance with the position of the magnet 7, the position into which the reactive gas is introduced is changed and the reactive gas is locally fed to the vicinity of the plasma 14, by which the compounding of the part not exposed to the plasma 14 with the reactive gas is suppressed, and the facts that the part is dielectrically broken down in the case of being exposed to the plasma to generate abnormal discharge are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering method and apparatus for forming a dielectric film on a large-area substrate by sputtering.

[0002]

2. Description of the Related Art A conventional sputtering apparatus will be described with reference to FIGS. In FIG. 6, a target 2 and a substrate 3 supported by a substrate support (not shown) are arranged opposite to each other in a vacuum vessel 1 connected to a ground potential. DC between target 2 and vacuum vessel 1
The power supply 4 is connected via the abnormal discharge prevention device 5.

The power supply 4 has a cathode connected to the target 2 and an anode connected to the vacuum vessel 1. The target 2 is insulated from the vacuum vessel 1 by an insulator 6. A magnet 7 is provided on the back surface of the target 2 and forms a magnetic force line 8 near the target. The magnet 7 is supported by a ball screw 9 so as to be movable in parallel with the target 2, and the magnet 7 is moved by rotating the ball screw 9 by a magnet moving motor 10. In addition, vacuum vessel 1
An exhaust port 11 for evacuating, a rare gas inlet 12 for introducing a rare gas such as Ar gas, and a reaction gas inlet 13 for introducing a reaction gas such as oxygen gas are provided.

A case where a tantalum oxide film is formed on a large-sized substrate 3 by using the sputtering apparatus having the above structure will be described as an example. The material of the target 2 is tantalum, and the material of the substrate 3 is glass. After the air in the vacuum vessel 1 is evacuated from the exhaust port 11 to make the inside of the vacuum vessel 1 high vacuum, Ar
As a gas, oxygen is introduced from the reaction gas inlet 13, and the gas pressure in the vacuum vessel 1 is set to several mTorr. When a high voltage is applied by the power supply 4 in such a state, plasma 14 is generated near the surface of the target 2.

[0005] Positive argon ions in the plasma 14 are incident on the target 2 at a negative potential, but the surface of the target 2 is oxidized by oxygen to form tantalum oxide.
When argon ions enter the target 2, tantalum oxide and secondary electrons are emitted. The secondary electrons collide with the argon molecules to ionize the argon molecules, and the released tantalum oxide deposits on the substrate 3 to form a thin film.
Here, the secondary electrons cannot travel straight because of the magnetic lines of force 8 and perform helical motion along the magnetic lines of force 8, so that the probability of the secondary electrons colliding with argon molecules is higher than in the case where there are no magnetic lines of force 8, so that the plasma is increased. The density also increases, and the consumption of the target 2 in the vicinity increases.

Therefore, the magnet 14 is moved in parallel to the target 2 by the magnet moving motor 10 and the ball screw 9, so that the plasma 14 is also moved. By the movement of the plasma 14, the entire target 2 can be used, and at the same time, a film can be formed on the large-sized substrate 3. Here, the abnormal discharge preventing device 5 prevents abnormal discharge by instantaneously applying a positive voltage to the target 2 and evacuating the electric charge charged in the tantalum oxide layer generated on the surface of the target 2.

[0007]

However, when a dielectric film is formed with the above-mentioned conventional structure, if the discharge power applied by the power supply 4 is increased in order to increase the film forming speed, abnormalities are left on the target 2. There is a problem that discharge occurs.
That is, as described above, the surface of the target 2 is oxidized to form a tantalum oxide layer. However, in the sputtering method using the entire surface of the target 2 by moving the magnet 7 and moving the plasma 14, the target 2 When the tantalum oxide layer on the surface of the surface 2 not exposed to the plasma 14 becomes too thick, and the portion is exposed to the plasma 14 due to the movement of the plasma 14, a high voltage is applied to both ends of the tantalum oxide layer and the tantalum oxide layer is applied. Dielectric polarization occurs in the layer, and if the voltage is too high, dielectric breakdown occurs and abnormal discharge occurs.

The abnormal discharge preventing device 5 instantaneously applies a positive voltage to the target 2 at a cycle of about several MHz to neutralize the electric charge on the surface of the tantalum oxide layer due to dielectric polarization.
Although the occurrence of abnormal discharge is prevented, its capability is limited, and if sputtering is performed with a discharge power exceeding the limit of the abnormal discharge prevention device 5, abnormal discharge will occur.

As a specific example, FIG. 7 shows a change in the discharge voltage when the discharge power is 3 KW and 6 KW in the above configuration. Here, there is a portion where the discharge voltage in the discharge at 6 KW is momentarily reduced, which is due to the abnormal discharge. It can be seen that the 3 KW discharge allows stable film formation without generating an abnormal discharge, but the 6 KW discharge causes abnormal discharge and does not allow stable film formation.

As described above, in the conventional configuration, the entire surface of the target 2 is oxidized because the reaction gas is supplied to the entire inside of the vacuum vessel 1, so that the tantalum oxide layer on the surface of the target 2 becomes too thick. When the tantalum oxide layer that has become too thick due to the movement of the plasma 14 is exposed to the plasma 14, dielectric breakdown occurs and abnormal discharge occurs. When the discharge voltage is low, abnormal discharge is prevented by the abnormal discharge prevention device 5, but its capability is limited,
When a high power exceeding the capacity of the abnormal discharge prevention device 5 is applied, abnormal discharge occurs, and it is difficult to increase the film forming speed.

The present invention has been made in consideration of the above-described conventional problems, and can prevent abnormal discharge from being generated on a target when a dielectric film is formed, and can increase a discharge power to increase a film forming speed. It is an object of the present invention to provide a sputtering method and apparatus that can perform the sputtering.

[0012]

According to the sputtering method of the present invention, a substrate and a target, each of which is made of a metal element among the elements constituting a dielectric film to be formed, are placed in a vacuum vessel so as to face each other. Then, the inside of the vacuum vessel is evacuated, a rare gas and a reaction gas are introduced, power is applied between the vacuum vessel and the target to generate plasma, a magnet arranged on the back of the target is moved, and the target is placed on the substrate. Is a method of forming a film of a compound of a substance and a reaction gas by changing a position where a reaction gas is introduced in accordance with a position of a magnet and locally supplying the reaction gas near a plasma on a target surface. Things.

As described above, the position where the reactant gas is introduced into the vacuum vessel is changed in accordance with the position of the magnet, and the reactant gas is locally supplied to the vicinity of the plasma on the target surface, thereby being exposed to the plasma. By suppressing the unreacted parts from reacting with the reaction gas and preventing the dielectric layer on the target surface from becoming unnecessarily thick, abnormalities caused by dielectric breakdown when the parts are exposed to the plasma due to the movement of the plasma. Discharge can be prevented. for that reason,
The deposition power can be increased by increasing the discharge power.

Further, the sputtering apparatus of the present invention provides a substrate, a substrate support, and an element constituting a dielectric film to be formed in a vacuum vessel having an exhaust port, a rare gas introduction port, and a reaction gas introduction port. Sputtering by disposing a target composed of metal elements inside to oppose, connecting a power supply between the vacuum vessel and the target, and disposing a movable magnet driven by a magnet moving motor on the back of the target In the apparatus, the reaction gas inlet is movably driven by a reaction gas inlet moving motor, and a magnet moving speed operating means for controlling the magnet moving motor to control the moving speed of the magnet and a reaction gas inlet moving. A reaction gas inlet moving speed operating means for controlling a motor to control a moving speed of the reaction gas inlet; and providing a signal to the magnet moving speed operating means and the reaction gas inlet moving speed operating means. Shin to having thereon a control means for moving the reaction gas inlet so as to correspond to the position of the magnet can exert its effects by implementing the sputtering method.

In addition, instead of moving the reaction gas inlet by means of the reaction gas inlet moving motor, a power transmitting means for transmitting the rotation of the magnet moving motor to the reaction gas inlet moving means may be provided. The effect can be achieved.

Instead of moving the reactant gas inlet, a plurality of reactant gas inlets are provided, and respective reactant gas flow control means are provided, and signals are transmitted to the magnet moving speed control means and the reactant gas flow control means. The same effect can be obtained by providing control means for changing the ratio of the flow rate of the reaction gas introduced from each reaction gas introduction port in accordance with the position of the magnet.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the sputtering apparatus of the present invention will be described with reference to FIGS. The configuration of the present embodiment is the same as that of the conventional sputtering apparatus except for the periphery of the target 2, and the description of the same components as those of the conventional example will be omitted, and only different points will be described.

In FIG. 1, the wall surface of the vacuum vessel 1 is not shown. The present embodiment is different from the conventional example in that the gas inlet 13 is configured to be movable by a gas inlet moving motor 15 and a ball screw 16, and the reaction gas inlet 13 is supplied with a reactive gas by a flexible tube 17. This is a point connected to the means (not shown). Magnet moving motor 10
Is connected to the magnet moving speed operating means 18, and the gas inlet moving motor 15 is connected to the reaction gas inlet moving speed operating means 19, respectively. Corresponding reaction gas inlet 1
3 can be changed.

The reaction gas inlet 13 is provided near one side of the target 2 so as to be movable in parallel with the side.
The exhaust port 11 is provided in the vicinity of a side opposite to the side of the target 2 where the reaction gas inlet 13 is provided. With such a configuration, oxygen introduced from the reaction gas introduction port 13 locally passes through a part of the surface of the target 2 and is exhausted from the exhaust port 11.

A case where a tantalum oxide film is formed on a large-sized glass substrate 3 using the apparatus having the above configuration will be described. The air in the vacuum vessel 1 is evacuated from the exhaust port 11 to make the inside of the vacuum vessel 1 high vacuum.
, An oxygen gas is introduced from the reaction gas inlet 13, and the gas pressure in the vacuum vessel 1 is set to 8 mTorr. A negative voltage is applied to the target 2 by the power supply 4 to generate plasma 14. A signal is transmitted from the arithmetic and control means 20, and the magnet 7 and the reaction gas inlet 13 are moved by the magnet moving motor 10 and the reaction gas inlet moving motor 15, so that the reaction gas inlet 13 is always near the plasma 14. Move to position. After the output from the power supply 4 is fixed at 6 KW and the magnet 7 and the reaction gas inlet 13 are reciprocated 20 times, the power supply from the power supply 4 is stopped, and the film formation is completed.

FIG. 2 shows a change in discharge voltage when a film is formed by the above method. The discharge voltage changes periodically because the impedance periodically changes due to the change in the position of the magnet 7. As shown in FIG. 2, by applying high power without causing abnormal discharge, film formation at a high film formation rate can be performed stably.

That is, in this embodiment, the reaction gas is locally supplied to the vicinity of the plasma 14 on the surface of the target 2, so that the portion not exposed to the plasma 14 is suppressed from being combined with the reaction gas, and By preventing the dielectric layer on the surface from being unnecessarily thick, the portion of the plasma
Abnormal discharge due to dielectric breakdown in the case of exposure to water can be prevented.

According to such a configuration, abnormal discharge does not occur even when discharging with high power, so that the film forming speed can be improved.

In this embodiment, the magnet 7 and the reaction gas inlet 13 are moved by using different motors 10 and 15, respectively, but the ball screw 9 and the ball screw 16 are moved by using one motor 10. The magnet 7 and the reaction gas inlet 13 may be moved by transmitting power using a power transmission means such as a gear or a belt.

Next, the second embodiment of the sputtering apparatus of the present invention will be described.
The embodiment will be described with reference to FIGS. The configuration of the present embodiment is the same as that of the conventional sputtering apparatus except for the periphery of the target 2, and the description of the same components as those of the conventional example will be omitted, and only different points will be described.

In FIG. 3, the wall surface of the vacuum vessel 1 is not shown. The present embodiment is different from the conventional example in that a plurality of reaction gas inlets 13a, 13b, and 13c are provided, and gas flow operation means 21a, 21b, and 21c are provided for each of them. Means 22
This is the point that can be controlled.

The position of the magnet 7 and the reaction gas inlets 13a, 1
FIG. 4 shows the relationship with the flow rate of oxygen flowing from 3b and 13c. Here, the reaction gas inlet 13a is located at the negative position of the magnet moving axis, the reaction gas inlet 13b is located at the center origin position,
The reaction gas inlet 13c is provided at a positive position of the magnet moving axis. As shown in the figure, the total amount of oxygen introduced from the three inlets is constant at 200 sccm, but a large amount of oxygen is introduced from the reaction gas inlet closest to the position of the magnet 7. Thus, oxidation of the surface of the target 2 that is not exposed to the plasma 14 is suppressed, and abnormal discharge on the surface of the target 2 is prevented.

FIG. 5 shows a change in the discharge voltage when discharging is performed by applying 6 kW of power from the power supply 4 in the manner described above.
Shown in The discharge voltage changes periodically because the impedance periodically changes due to the change in the position of the magnet 7. As shown in FIG. 5, high power can be applied without generating abnormal discharge, and a film can be stably formed at a high film forming speed.

As described above, the reaction gas is locally supplied to the vicinity of the plasma 14 on the surface of the target 2 so that the plasma 1
By suppressing the portion that is not exposed to the reaction gas from being combined with the reaction gas, the dielectric layer on the surface of the target 2 is prevented from being unnecessarily thick, and the portion is prevented from being exposed to the plasma 14.
This prevents abnormal discharge due to dielectric breakdown when exposed to the plasma 14 due to the movement of, and abnormal discharge does not occur even when discharging with high power, so that the film forming speed can be improved.

According to this embodiment, unlike the first embodiment, there is no danger that the film will peel off due to the physical movement of the object inside the vacuum vessel 1, and it will not cause dust generation. There is an advantage.

In this embodiment, the number of reaction gas inlets is three, but it goes without saying that more reaction gas inlets may be provided.

[0032]

According to the sputtering method and apparatus of the present invention, as is apparent from the above description, the magnet arranged on the back surface of the target is moved to form the compound of the target substance and the reactive gas on the substrate. In the sputtering method for forming a film, the position where the reactant gas is introduced is changed according to the position of the magnet, and the reactant gas is locally supplied to the vicinity of the plasma on the target surface, so that the target is not exposed to the plasma. The part can be suppressed from being combined with the reaction gas, and the dielectric layer generated by the combination on the target surface is not unnecessarily thick, so that when the part is exposed to the plasma due to the movement of the plasma. Abnormal discharge due to dielectric breakdown can be prevented, and therefore the effect of increasing the discharge power and increasing the deposition rate can be achieved. That.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration around a target of a sputtering apparatus according to a first embodiment of the present invention.

FIG. 2 is a graph showing a change in discharge voltage in the same embodiment.

FIG. 3 is a perspective view showing a configuration around a target of a sputtering apparatus according to a second embodiment of the present invention.

FIG. 4 is a graph showing a relationship between a magnet position and a reactant gas flow rate from each reactant gas inlet in the embodiment.

FIG. 5 is a graph showing a change in discharge voltage in the same embodiment.

FIG. 6 is a cross-sectional view illustrating a configuration of a conventional sputtering apparatus.

FIG. 7 is a graph showing a change in discharge voltage in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Target 3 Substrate 4 Power supply 7 Magnet 9 Ball screw 10 Magnet moving motor 11 Exhaust port 12 Rare gas inlet 13 Reaction gas inlet 13a, 13b, 13c Reaction gas inlet 15 Reaction gas inlet motor 16 Ball screw 17 Flexible tube 18 Magnet moving speed operating means 19 Reaction gas inlet moving speed operating means 20 Arithmetic control means 21a, 21b, 21c Gas flow rate operating means 22 Arithmetic control means

 ──────────────────────────────────────────────────の Continuing on the front page (72) Munekazu Nishihara, 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Yoichi Imai 1006 Kadoma, Kazuma, Kadoma, Osaka Pref.

Claims (4)

[Claims] 1. A vacuum container comprising: a target formed of a metal element among elements constituting a dielectric film to be formed; and a substrate disposed opposite to each other. And a reaction gas are introduced, power is applied between the vacuum vessel and the target to generate plasma, a magnet arranged on the back of the target is moved, and a compound of the substance in the target and the reaction gas is formed on the substrate. A method of supplying a reactive gas locally near a plasma on a target surface by changing a position for introducing a reactive gas in accordance with a position of a magnet. 2. A vacuum vessel having an exhaust port, a rare gas introduction port, and a reaction gas introduction port, which is composed of a metal element among elements constituting a substrate, a substrate support, and a dielectric film to be formed. Gas supply port is connected between the vacuum vessel and the target, and a movable magnet driven by a magnet moving motor is provided on the back of the target. Is driven by a reaction gas inlet moving motor to control the magnet moving speed by controlling the magnet moving motor and the reaction gas inlet moving motor to control the reaction gas inlet moving motor. Providing reaction gas inlet moving speed operating means for controlling the moving speed of the inlet, transmitting a signal to the magnet moving speed operating means and the reacting gas inlet moving speed operating means, and reacting the reactant gas in accordance with the position of the magnet. A sputtering apparatus provided with control means for moving an inlet. 3. A vacuum vessel having an exhaust port, a rare gas introduction port, and a reaction gas introduction port, which is made of a metal element among elements constituting a substrate, a substrate support, and a dielectric film to be formed. Gas supply port is connected between the vacuum vessel and the target, and a movable magnet driven by a magnet moving motor is provided on the back of the target. Power transfer means for movably supporting the magnet, controlling a magnet movement motor to operate the magnet movement speed and providing magnet movement speed operation means, and transmitting the rotation of the magnet movement motor to the reaction gas inlet movement means. And a control means for transmitting a signal to the magnet moving speed operation means to control the position of the magnet and the position of the reaction gas inlet. 4. A vacuum vessel having an exhaust port, a rare gas introduction port, and a reaction gas introduction port, which is made of a metal element among elements constituting a substrate, a substrate support, and a dielectric film to be formed. In a sputtering apparatus in which a power source is connected between the vacuum vessel and the target and a movable magnet driven by a magnet moving motor is provided on the back surface of the target, a plurality of reactive gases are provided. In addition to providing an inlet, a reaction gas flow rate operation means is provided for each, and a magnet movement speed operation means for controlling a magnet movement motor to operate a magnet movement speed is provided. The magnet movement speed operation means and the reaction gas flow rate operation means are provided. Characterized in that control means is provided for changing the ratio of the flow rate of the reactant gas introduced from each reactant gas inlet in accordance with the position of the magnet by transmitting a signal to the magnet. .