JPH03166367A - Method and device for sputtering - Google Patents

Abstract

PURPOSE:To coat a substrate with a film at a stable and high rate by allowing a target material sputtered by the inert gas ion generated by the specified first process to react with the reactive gas ion generated by the second process. CONSTITUTION:The electron generated in a first accelerated beam source 6a is drawn into a vacuum vessel 1, and allowed to collide with an inert gas to produce plasma 15 contg. the inert gas ion in the vicinity of the surface of a target material 3. The inert gas ion is accelerated by a sputtering cathode 2 and allowed to collide with the material 3 which is sputtered. As the second process in succession to the first process, the electron generated in the second accelerated plasma electron beam source 6b is allowed to collide with a reactive gas 14 to produce the second plasma 16. The sputtered material 3 is passed through the plasma 16 and subjected to a reaction to coat the substrate 20 with the compd. of the material 3.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a film coated on a transparent glass substrate of heat-reflecting glass or heat insulating glass used for architecture, automobiles, etc.
In particular, the present invention relates to a method and apparatus for stably coating a large-area substrate with a film having electrical insulation properties at a high coating rate.

[Conventional technology]

As disclosed in Japanese Patent Laid-Open No. 63-223171, a method of coating a substrate with a film using the Suba Notaring method involves performing arc discharge along a magnetic field independently of the target material, and There is a method of sputtering a target material by applying a negative bias voltage to the target and causing gas ions to collide with the target. In this method, the discharge current can be controlled independently of the negative bias voltage applied to the target, making it possible to discharge a large current by taking advantage of the characteristics of arc discharge, and the incident ion current density to the target is also lower than that of the conventional magnetron sputtering method. It is possible to significantly increase the
As a result, sputtering speed is significantly improved. Also,
Since it is a hot cathode discharge, the discharge gas pressure is also 1.3 3
It is also possible to lower the pressure to as low as 10-''Pa, which makes it possible to reduce scattering caused by collisions with atmospheric gases that occur during the flight of the sputtered target material to the substrate.

[Problem to be solved by the invention]

However, in the conventional sputtering method using arc discharge plasma, there is a problem in that when forming a dielectric film by reactive sputtering, the sputtering speed, that is, the film deposition speed on the substrate is significantly reduced.

That is, when forming a dielectric film by the conventional method,
Usually, a metal with a dielectric coating is placed as a target on the Svanter cathode, and the target is generated near the target by an arc discharge consisting of a mixed gas of an inert gas and a reactive gas such as oxygen or nitrogen. By forming a sheet plasma and colliding the inert gas ions and reactive gas ions present in this sheet plasma with the target material to which a negative bias voltage is applied independently of the plasma, the atoms of the target material are is sputtered, and the atoms of the target material ejected from the target material react with the reactive gas in the plasma, thereby forming a dielectric film of oxide, nitride, or the like of the target material on the substrate. However, since this method generates plasma containing reactive gas near the sputtering target, there are many flanks of neutral reactive gas and reactive gas ions that are incident on the target surface, and the interaction between the target material and the reactive gas increases. A compound layer formed on the target surface is formed. Typically,
Comparing the sputtering speeds of metals and metal compounds,
Since the sputtering rate of the metal compound is significantly lower, this results in a reduction in the total amount of material sputtered from the target and a reduction in the rate of film deposition on the substrate. Furthermore, the formation of an insulating layer on the target surface causes the target surface to become electrically charged, and sometimes arcing occurs on the target surface, making it difficult to perform sputtering stably.

[Means to solve the problem]

The present invention has been made to solve the above problems, and provides a method and apparatus for coating a large-area substrate with a uniform film while having a high film-forming rate. .

The method of the present invention is a method in which a substrate is coated by sputtering with a target material placed on a sputtering cathode in a vacuum chamber where a reduced pressure atmosphere can be adjusted. 1 and subsequent to the first process, the sputtered target material passes through a plasma containing a reactive gas generated between the substrate and the target material, or a reactive gas and an inert gas. a second process in which the first process
The electrons generated in the accelerated plasma electron beam source and then electrically accelerated and extracted into the vacuum chamber collide with mainly inert gas in the atmospheric gas, so that an inert gas is generated near the surface of the target material. A sputtering process in which a plasma containing ions is generated, and inert ions in the plasma are accelerated by a negative voltage applied to the sputtering cathode and collide with the target material,
The second process combines electrons generated in a second accelerated plasma electron beam source and then electrically accelerated and extracted into the vacuum chamber with a reactive gas in the atmosphere or with a reactive gas. A process of generating a second plasma through collision with an active gas and causing the sputtered material to react with the reactive gas by passing the sputtered material through the second plasma. .

The plasma generated by the first plasma electron beam source for sputtering the target material is preferably an arc discharge plasma that can obtain a large discharge current, in order to increase the sputtering rate. The cathode for generating electrons in the source is
A hot cathode that can emit a large amount of electrons in a high vacuum is preferable. Furthermore, in order to efficiently react the sputtered target material with the reactive gas, a second
The plasma generated by the plasma electron beam source is
Similarly, it is preferable to use an arc discharge plasma that can obtain a large discharge current, and the cathode for generating electrons in the second plasma electron beam source is a hot cathode like the first plasma electron beam source. is preferred.

In addition, when a large area target material is used to coat a large area substrate with a film, the plasma generated by the first plasma electron beam source covers the entire surface of the target material and at the same time does not sputter. It is preferable that most of the target material passes through the plasma generated by the second plasma electron beam source. Therefore, the shape of the plasma is sheet-like, that is, flat, and the sheet surface is close to the target surface. and is preferably substantially parallel to the substrate surface.

In order to obtain plasma with the shape described above, what is the example? It is possible to use the method disclosed in Japanese Patent Application Laid-Open No. 59-27499, in which an electromagnet or permanent magnet can be placed inside or outside the tank.

The sputtering apparatus of the present invention includes a vacuum chamber in which the surrounding gas can be adjusted, and a sputtering cathode electrically connected to the vacuum chamber, and a sputtering cathode having a width opposite to the sputtering cathode. means for holding the substrate to be coated with a coating; A first plasma generating device comprising a plasma electron beam source and a first anode for drawing out the electrons generated by the first plasma electron beam source into the vacuum chamber; and the vacuum chamber. A second plasma electron beam source, which is electrically insulated and provided so as to generate a plasma near the surface of the substrate, and draws electrons generated by the second plasma electron beam drift into a vacuum chamber. a second plasma generator comprising 42 anodes; means for externally supplying electric power to the first and second plasma electron beam sources and the first and second anodes; The sputtering apparatus includes means for introducing gas into the sputtering apparatus and exhaust means.

In addition, in order to coat a large-area substrate with a homogeneous film, it is necessary to
The shape of the two plasmas is a sheet, and in order to make the sheet surface almost parallel to the target surface of the sputtering cathode, a magnetic field is formed in a direction from the plasma electron beam source to an anode placed opposite to the sputtering cathode. It is preferable to provide a core coil and a pair of permanent magnets that have a magnetic field in a direction perpendicular to the direction of the magnetic field and are arranged so that their north poles face each other.

Further, in the apparatus according to the present invention, the inside of the vacuum chamber is separated into a space in which plasma is generated by the first plasma electron beam source and a space in which plasma is generated by the second plasma electron beam source, and Providing a partition with an opening so that the sputtered target material adheres to the substrate is effective in preventing the reactive gas of the second plasma from diffusing and flowing into the surface of the target material. It is preferable.

Furthermore, a known vacuum pump can be used to exhaust the entire atmosphere within the vacuum chamber. The exhaust port of the vacuum exhaust bomb is preferably provided in a vacuum wall closer to the second plasma space than the first plasma space.

Further, the power source used for the sputtering cathode used in the present invention is not particularly limited, but a DC power source is preferably used in order to perform stable sub-notering.

[Effect]

Inert gas ions in the plasma generated near the target surface by the first plasma electron beam source collide with the target material due to the negative voltage applied to the sputter cathode, thereby sputtering the target material. The reactive gas and reactive gas ions in the plasma generated near the substrate surface by the second plasma electron beam source react efficiently with the sputtered target material to create a reactive substance. At this time, the reactive gas is introduced near the substrate surface, which is farther from the target surface, so that it is inhibited from reaching the target material surface, and the formation of a compound between the target material and the reactive gas on the target surface is inhibited. The sputtering speed of the target material can be increased.

By shaping the first plasma into a sheet whose sheet surface is substantially parallel to the target surface, the entire target surface can be sputtered.

By shaping the second plasma into a sheet whose sheet surface is substantially parallel to the substrate, it is possible to increase the flow east cross-sectional area of the target material that reacts with the reactive gas and flies toward the substrate.

Further, the partition wall in the vacuum chamber according to the apparatus of the present invention functions to reduce the conductance when the reactive gas diffuses to the target surface.

[Examples] The present invention will be described below based on Examples. FIG. 1 is a schematic cross-sectional view of one embodiment of an apparatus for carrying out the sputtering method of the present invention.

In a vacuum chamber 22, a target material is placed as a sputtering target on a sputtering cathode 2 electrically insulated from the vacuum chamber 1. The vacuum chamber 1 is evacuated from an exhaust port 2l connected to a vacuum pump (not shown). First and second plasma electron beam sources 6 a + 6 b for generating a sheet-like plasma spread horizontally above the Yuichi target material 3
and anode 13a. 13b is arranged to be electrically insulated from the vacuum chamber 1 via the electrical insulator 4. In order to generate plasma, gas supply pipes 8a, 3 are connected to the hot cathodes 7a, 7b of the first and second plasma electron beam sources.
An inert gas such as ^r is introduced from b, and the cathode? a,
7b, a discharge power source 11a. Supplies direct current from 1 lb. The generated plasma is transferred to plasma electron beam sources 6a and 5b.
The air-core coil 12 for plasma induction placed near the anodes 13a and 13b, which are placed opposite to this, generates magnetic fields directed from the plasma electron beam sources 6a and 6b toward the anodes 13a and 13b, respectively. anode 13
a. Pull it out to 13b. Further, electrons are extracted into the vacuum chamber 22 by the intermediate electrodes 9a and 9b, and a sheet plasma 15, 16 is formed by the permanent magnet 10 for plasma compression. Further, the sheet plasma 16 becomes a plasma containing a reactive gas by supplying a reactive gas from the reactive gas supply pipe 14.

On the opposite side of the sheet plasma l5 from the target material 3,
A partition wall 18 having an opening l7 is provided. The substrate 20 to be coated is held by a substrate holding jig 19 at the upper part of the vacuum chamber 1, facing the target material 3.

In order to perform sputtering, a negative bias is applied to the sputtering cathode 2 by a DC power supply 5. When a negative bias voltage is applied to the sputtering cathode 2,
Among the inert gas ions generated in the sheet plasma 15 by the inert gas, the ions that have reached the vicinity of the target surface by thermal diffusion are accelerated by a negative bias voltage.
It collides with the target with high energy and the target material 3 is sputtered at that time. After passing through the opening 17, the sputtered substance passes through a certain sheet plasma 16 from the reactive gas near the substrate, by reacting with ions or excited species of the reactive gas present in the plasma. A compound of the target material and the reactive gas is generated, and a thin film of the compound of the target material 3 is coated on the substrate.

A specific example is shown below. The target size at this time is 8 inches in diameter and 5fi in thickness, the distance between the base and the target material is 500 m, the distance between the sheet plasma 15 and the target material is about 3 Q mm, the distance between the sheet plasma 16 and the base 20 is about 50 mm, The distance between the partition wall 18 and the sheet plasma 15 was approximately 25 mm, and the area of the opening 17 was approximately the same as that of the target material 3.

A dielectric film was coated on a glass substrate using the apparatus described above.

Example 1 First, conductive Si was placed on the upper surface of the sputtering cathode 3 as a sputtering target material. Then,
A glass plate 20 on which a coating is to be formed was held by a substrate holding jig 19. Thereafter, the pressure in the vacuum chamber 22 was reduced to about 10<-3>Pa using a vacuum pump (not shown). Then,
an inert gas supply pipe 8a within the plasma electron beam source;
30 scca+ of Ar gas was introduced as an inert gas from 8b. In this state, a current of 20 A is applied to the air-core coil 12 to form a magnetic field in the direction from the plasma electron beam source toward the anode, and then the plasma electron beam source 6a. A current of about 50 A is supplied to the anode 6b, and a large current of about 60 A/cd is taken out by heating the hot cathodes 7a and 7b.
Plasma was generated between the two. The strength of the magnetic field produced by the air-core coil was measured separately with a Gaussmeter and was approximately 105 Gauss at the center of the vacuum chamber. The plasma generated between the plasma electron beam source and the anode is turned into a sheet-like plasma by the square permanent magnet 10 for plasma compression (made of Sm-Co, approximately 2.5 k Gauss at the surface), and the size of the plasma is approximately 2.5 k Gauss wide. 40COl, length approximately 60CI1
, thickness approx. It was a sheet plasma of 5cII1. Next, about 605 ccffl of oxygen gas was supplied as a reaction gas from the reaction gas supply pipe 14 to the sheet plasma, forming a sheet plasma 16 containing the reaction gas.

In this state, the DC power supply 5 is connected to the sputtering cathode 3.
By applying a negative bias voltage of about 200 V, St
Target sputtering was performed. After continuing sputtering for about 150 seconds, the sputtering is stopped by turning off the DC power supply 5, and further, the discharge is stopped by turning off the DC power supplies 11a and 11b for sheet plasma, and a certain film process is completed. did. During this time, no abnormal discharge (arcing) was observed on the target surface. In this way, a silicon oxide film was formed on the glass plate 20. Next, the vacuum chamber 22 was returned to the atmosphere, and the glass plate coated with silicon oxide was taken out. The thickness of the coated thin film was measured using a surface roughness meter and found to be 1,950. In addition, when the optical constants of the thin film were measured using an ellipsometer, the refractive index was 1.4 at a wavelength of 630 nn+.
64. It was a transparent film with no absorption and an extinction coefficient of 0.00. Example 2 The same operation as in Example 1 was performed except that the reaction gas was a mixed gas of 25 sec of oxygen gas and 50 sccm of nitrogen gas, and an attempt was made to form a silicon nitride oxide film. After sputtering for 150 seconds, the coating was completed, the vacuum chamber was brought to the atmosphere, and the glass plate and Si wafer coated with the silicon nitride oxide film were taken out. While sputtering was being performed, no arcing was observed on the target surface as in Example 1. S
When the infrared absorption spectrum of the film on the i-wafer was measured, absorption peaks due to St-N and Si-0 bonds were observed near 850 cn-' and 1060-' cm, respectively, indicating that the obtained film was a silicon nitride oxide film. It was confirmed that.

Furthermore, the thickness of the coated thin film was measured using a surface roughness meter and found to be 1,780 people. Furthermore, when the optical constants were measured using an ellipsometer, the film was found to be a transparent thin film with no absorption and a refractive index of 1.62 and an extinction coefficient of 0.00 at a wavelength of 633 nm.

〔Effect of the invention〕

According to the present invention, it is possible to coat a substrate with a dielectric film extremely stably and at a high deposition rate. In addition, when using a large-area target to coat a large-area substrate with a film, a uniformly spread sheet plasma is used as the ion source for sputtering.
Since the entire surface of the target is sputtered, the target separation efficiency is high.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a sputtering apparatus used in carrying out the present invention. 1... Vacuum chamber 2... Sputtering cathode 3... Target material 5... Twisting power source 6... Plasma electron beam source 7 ... Hot cathode 8 ... Inert gas supply pipe 10 ... Permanent magnet for plasma compression 11 ... Discharge power source 2 ... Air core coil for plasma induction 3 ... Anode 4... Reactive gas supply pipe 5.16... Sheet plasma 6... Reactive gas sheet plasma 7... Opening 8... Partition wall 9... Substrate holding jig O... Substrate 1 ···exhaust port

Claims (1)

[Claims] 1) A method of coating a substrate by sputtering with a target material placed on a sputtering cathode in a vacuum chamber in which a reduced pressure atmosphere can be controlled, the method comprising sputtering the target material mainly with inert gas ions. 1 and subsequent to the first process, passing the sputtered target material through a plasma containing a reactive gas generated between the substrate and the target material, or a reactive gas and an inert gas. and a second process in which the first process generates electrons in the first accelerated plasma electron beam source and then electrically accelerates and extracts them into the vacuum chamber. , a plasma containing inert gas ions is generated near the surface of the target material by collision with mainly an inert gas in the atmospheric gas, and the inert gas ions in the plasma are accelerated by a negative voltage applied to the sputtering cathode. The sputtering process is a sputtering process in which electrons are generated in a second accelerated plasma electron beam source and then electrically accelerated and extracted into the vacuum chamber. , generating a second plasma by collision of a reactive gas in the atmosphere or a reactive gas and an inert gas, and passing the sputtered material through the second plasma; A method characterized in that it is a process of causing a reaction between a sputtered substance and a reactive gas. 2) The method of claim 1, wherein the electrons in the plasma electron beam source are generated by a hot cathode and the first and second plasmas are arc discharge plasmas. 3) The method according to claim 1 or 2, wherein the shape of the plasma in the first and second processes is sheet-like, and the sheet surface is parallel to the surface of the target. . 4) A vacuum chamber in which a reduced pressure atmosphere can be adjusted, and a means for placing a target material in the vacuum chamber. A first means for holding the substrate to be overturned and the vacuum chamber are electrically insulated and are provided so that plasma is generated near the surface of the sputtering cathode.
a first plasma generation device comprising a plasma electron beam source and a first anode for extracting electrons generated by the first plasma electron beam source into the vacuum chamber; a second plasma electron beam source, which is insulated from the substrate and is provided so that plasma is generated near the surface of the substrate; and a second plasma electron beam source for extracting electrons generated by the second plasma electron beam source into the vacuum chamber. a second plasma generator comprising two anodes, a means for externally supplying electric power to the first and second plasma electron beam sources and the first and second anodes, and a means for supplying gas into the vacuum chamber. and means for introducing and discharging. 5) The shape of the plasma generated near the surfaces of the sputter cathode and the base body is sheet-like, and the plasma is directed from the plasma electron beam source toward the anode so that the sheet surface is parallel to the target installation surface of the sputter cathode. an air-core coil that forms a magnetic field; and 1 that has a magnetic field in a direction perpendicular to the direction of the magnetic field and that are arranged so that their north poles face each other.
5. The device according to claim 4, further comprising a pair of permanent magnets. 6) Separating the inside of the vacuum chamber into a space where plasma is generated by the first plasma generator and a space where plasma is generated by the second plasma generator; 6. The device according to claim 4 or 5, characterized in that a partition wall with an opening is provided in the vacuum chamber so that the material adheres to the substrate. 7) The apparatus according to claim 6, wherein the opening is located almost directly above the sputtering cathode, and the area of the opening is approximately equal to the area of the sputtering cathode.