JPH09310176A - Magnetron sputtering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a uniform distribution of coating quality in coating formation by a magnet moving type magnetron sputtering device generating race track-shaped plasma in which one side is long. SOLUTION: In the case, with the center of race track plasma 23 in the surface of a target as the original point, the longitudinal direction of the race track plasma 23 is defined as the (x)-axis and the direction vertical to the (x)-axis in the surface of the target as the (y)-axis, the relation between the magnet flux density components Bzx vertical to the target in a position at which the magnet flux density components parallel to the target are made zero and the magnet flux density components Bzy vertical to the target in a position at which the magnet flux density components parallel to the target are made zero on the (y)-axis in the side outer than the race track plasma 23 satisfies Bzx<0.8×Bzy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron sputtering apparatus, and more particularly to a magnetron sputtering apparatus having an improved magnetic pole used in a process of manufacturing a liquid crystal display.

[0002]

2. Description of the Related Art Large-screen liquid crystal displays are used in portable personal computers and the like, and the demand thereof is expanding with the spread of personal computers. Generally, in the manufacturing process of a large-screen liquid crystal display, especially in the manufacturing of a liquid crystal display using a TFT (Thin-Film Transistor), sputtering or chemical vapor deposition (CVD) is performed on a glass plate.
A process of repeatedly forming a thin film represented by, for example, and processing of the thin film such as photolithography and etching is used.

The screen size of a liquid crystal display is required to be large from the viewpoint of visibility, and from the viewpoint of cost reduction, there is a demand to manufacture a large number of products from one piece of glass. It is necessary to increase the size of the substrate to be processed such as film formation.

A magnetron sputtering apparatus is often used for forming electrodes on glass. The basic configuration of the magnetron sputtering apparatus is described in, for example, “Spattering Phenomenon” by Yutaka Kanehara (Tokyo University Press), p161.

That is, a sputtering target (hereinafter, simply referred to as a target) which is a thin film base material is placed in a vacuum container, and a tunnel-shaped magnetic field is formed on the target surface by an electromagnet or a permanent magnet. When a negative voltage is applied to the target, an electric field is generated on the target surface, and the electric field causes ions in the plasma to collide with the target. The substance constituting the target is scattered at the atomic level by the impact when the ions collide. A thin film is formed by the scattered particles adhering to the substrate.

Further, secondary electrons are emitted from the target by the impact of ions. Since the target is a negative potential,
Secondary electrons are accelerated by the electric field on the target surface and are emitted into the gas. Secondary electrons are constrained by a tunnel-shaped magnetic field and move along a racetrack in a tunnel of a magnetic field, so that the probability of collision with gas increases. The secondary electrons collide with the gas and ionize the gas. As a result, racetrack-shaped plasma is formed.

In the magnetron sputtering method, high-density plasma can be easily obtained, high-speed film formation can be performed, and a rise in substrate temperature can be suppressed. However, when a magnet is fixed and used, plasma is locally generated. Since it is concentrated on the surface of the target, it is difficult to form a uniform film on a large area and the target is locally worn away. Therefore, move the board,
Alternatively, a uniform film is formed on a large area substrate by moving a magnet or the like.

In manufacturing a liquid crystal display, a single-wafer type magnetron sputtering apparatus for processing substrates one by one is used. As the structure of the electrode, for example,
As described in JP-A 7-233473, by using a magnet assembly for moving a magnetic field to form a magnetic field on the target surface, it is possible to achieve a uniform film thickness within a large-area glass substrate. it can.

Since a computer display is usually quadrangular, when the liquid crystal display is used for a computer, the glass substrate to be handled is also quadrangular. Therefore, the shape of the sputter target is basically a quadrangle, and the magnet has a rectangular shape with one side. By moving the magnet, the film thickness of the film formed on the substrate is made uniform. .

Since a magnet with a long side is used as the magnet, the trajectories of the electrons confined on the target surface are also racetrack-like with a long side. Therefore, the plasma formed on the target surface also has a racetrack shape. This situation is, for example, Brian N. Chapman
Written by Yukio Okamoto in "Basics of Plasma Processing" (Denki Shoin), p.248. When forming a film on a large-area substrate, the magnet is moved in the direction of the short side of the race track to ensure the uniformity of the film thickness.

[0011]

When a racetrack-shaped plasma is formed by a magnet based on a rectangle having a long side, a portion of the racetrack having a large curvature,
The plasma density is different from the straight part of the racetrack. This is because the path taken by the electrons emitted from the target surface to reach the ground electrode is different between the straight portion and the curved portion of the racetrack. The electrons must drift along the racetrack and be absorbed by the ground electrode after ionizing the gas. Since the electrons existing in the straight part of the racetrack have a large distance to the ground electrode, they must be accelerated at a high speed when they are emitted from the target surface. However, as the glass substrate becomes larger, it is necessary to enlarge the long side direction of the race track, which causes a problem that the difference in plasma density between the portion having a large curvature and the straight portion of the race track increases.

The present invention has been made in view of the above points,
An object of the invention is to provide a magnetron sputtering apparatus capable of generating a uniform film quality distribution even when a racetrack-shaped plasma having a long side is generated and a film is formed on a large glass substrate, for example. is there.

[0013]

In order to solve the above problems, according to the present invention, the maximum value of the vertical magnetic field at the end of the magnet in the long-side direction is defined as the maximum value of the target surface magnetic field generated by a magnet whose base is long. It is characterized in that the maximum value of the vertical magnetic field in the short side direction of the magnet is 0.8 times or less.

With such a structure of the present invention, the electrons existing in the racetrack curve portion can easily reach the anode, so that the electrons emitted from the center of the target also need a large kinetic energy. You can reach the anode without doing. As a result, the plasma density distribution on the race track can be made uniform, so that the film obtained on the substrate also has good uniformity.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on the illustrated embodiments. The present invention is particularly effective when a compound thin film such as a tin-doped indium oxide thin film (hereinafter referred to as an ITO film) is formed by sputtering.
An example in which the present invention is applied to sputter deposition of an O thin film will be described.

FIG. 1 is a diagram showing a position where a magnetic field should be adjusted in the present invention, and FIG. 2 is a diagram showing a positional relationship between a magnetic pole and a target. FIG. 1 is a view of the magnet assembly viewed from the positive direction of the z axis in FIG. Also, FIG.
Also, the x-axis and the y-axis in FIG.
It should be on the surface of 1.

The magnet assembly used in this embodiment comprises an inner circumference magnet 22, an outer circumference magnet 21, and a yoke plate 25, and a tunnel-shaped magnetic field 24 is formed on the surface of the target 31. . Racetrack-shaped plasma 23 is generated on the surface of the target 31. The secondary electrons emitted from the target 31 are
After drifting along the plasma 23, it is absorbed by the anode.

The target horizontal magnetic field 13 on the y-axis and the target vertical magnetic field 11, x on the x-axis shown in FIGS. 1 and 2.
The values of the target horizontal magnetic field 14 on the axis and the target vertical magnetic field 12 on the x-axis are shown in FIG.

The present invention is characterized in that, among the magnetic field intensities shown in FIG. 3, the target horizontal magnetic field 14 on the x-axis and the target vertical magnetic field 12 on the x-axis are smaller than those in the prior art. The ITO film was formed under the conditions shown in FIG. In order to realize the conditions shown in FIG.
The width w1 of the outer peripheral magnet 21 shown in FIG. 4 is made smaller than w2. Further, as shown in FIG.
A similar magnetic field can be realized by sticking the to the outer peripheral magnet 21.

The present inventors have found that the sputter power is 1.5 kW,
Sputtering gas Ar + 0.5% O ₂ , sputtering pressure 0.5P
a, the substrate heating temperature is 200 ° C., 370 mm × 470 mm
A film was formed on the glass substrate of No. 170 for 170 seconds. During film formation, the magnet assembly oscillated in the y-axis direction. In order to examine the uniformity of the film quality of the ITO film, the resistivity distribution was obtained from the film thickness distribution and the sheet resistance distribution for comparison.

FIG. 6 shows the resistivity distribution when the magnetic field strength is changed to. In particular, and are the target vertical magnetic field 12 on the x-axis and the target vertical magnetic field 11 on the y-axis.
When it is less than 0.8 times, the resistivity distribution is remarkably improved. In the longitudinal direction of the magnet assembly, conventionally, the resistivity of the central portion of the substrate was higher than that of the end portion of the substrate, whereas by weakening the magnetic field at the end portion of the magnet assembly,
We found that the resistivity of the central part of the substrate decreased. This improves the uniformity of resistivity in the plane of the substrate,
The permeability is also improved, and a uniform film quality distribution can be obtained.

[0022]

According to the magnetron sputtering apparatus of the present invention described above, the maximum value of the vertical magnetic field at the end of the magnet in the long side of the target surface magnetic field generated by a magnet having a rectangular shape with one side being the short side is defined as Since the maximum vertical magnetic field in the side direction is 0.8 times or less, the electrons existing in the racetrack curve can easily reach the anode. It is possible to reach the anode without requiring a large amount of kinetic energy, and as a result, the plasma density distribution on the racetrack can be made uniform, so that the film obtained on the substrate also has good uniformity. To be

[Brief description of drawings]

FIG. 1 is a diagram showing a position where a magnetic field should be adjusted in a magnet assembly used in a magnetron sputtering apparatus of the present invention.

FIG. 2 is a diagram showing a positional relationship between magnetic poles and a target in the magnet assembly shown in FIG.

FIG. 3 is a table showing respective values of a target horizontal magnetic field on the y axis, a target vertical magnetic field on the y axis, a target horizontal magnetic field on the x axis, and a target vertical magnetic field on the x axis shown in FIGS. 1 and 2. Is.

FIG. 4 is a diagram showing an outline of a magnet assembly adopted in the magnetron sputtering apparatus of the present invention.

FIG. 5 is a partial perspective view showing a magnet assembly used in the magnetron sputtering apparatus of the present invention.

FIG. 6 is a characteristic diagram showing a resistivity distribution when the magnetic field strength is changed.

[Explanation of symbols]

11 ... y-axis target vertical magnetic field, 12 ... x-axis target vertical magnetic field, 13 ... y-axis target horizontal magnetic field, 14
… Target horizontal magnetic field on x-axis, 21… Perimeter magnet,
22 ... Inner circumference magnet, 23 ... Plasma, 24 ... Tunnel magnetic field, 25 ... Yoke plate, 26 ... Magnetic material, 31 ... Target, 32 ... Backing plate.

Continuation of the front page (72) Inventor Mitsuhiro Kamei 1-1-1, Kokubuncho, Hitachi City, Ibaraki Prefecture Inside the Kokubu Plant of Hitachi, Ltd.

Claims (3)

[Claims] 1. A sputter target in a vacuum container, and a mechanism for disposing a substrate to which a film is to be attached at a position facing the sputter target, wherein a magnetron magnetic field is formed on a surface of the sputter target. A magnetic field generating means that is movable parallel to the sputter target surface is provided inside or outside the vacuum container, and a DC voltage or an AC voltage is applied to the sputter target to form a geometrical pattern on the sputter target surface. In a magnetron sputtering apparatus for generating a racetrack-shaped plasma that is point-symmetrical and long in one direction to deposit a film on the substrate, the racetrack-shaped plasma is formed with the center of the racetrack-shaped plasma on the sputter target surface as the origin. With the longitudinal direction of the plasma as the x-axis, the sputter target Vertical to the sputter target at a position where the magnetic flux density component parallel to the sputter target on the x axis outside the racetrack-shaped plasma is 0 when the direction perpendicular to the x axis on the surface of the gut is the y axis. Of the magnetic flux density component Bzx and the magnetic flux density component Bzy perpendicular to the sputter target at a position on the y axis outside the racetrack-shaped plasma where the magnetic flux density component parallel to the sputter target is zero. , Bzx
A magnetron sputtering apparatus characterized in that <0.8 × Bzy. 2. A vacuum container having a sputter target and a mechanism for disposing a substrate on which a film is to be deposited at a position facing the sputter target, wherein the magnetron magnetic field is formed on the surface of the sputter target. A magnetic field generating means by a permanent magnet movable parallel to the sputter target surface is provided inside the vacuum container or outside the vacuum container, and a DC voltage or an AC voltage is applied to the sputter target to the sputter target surface, In a magnetron sputtering apparatus for generating a racetrack-shaped plasma that is geometrically point-symmetrical and long in one direction to deposit a film on the substrate, the racetrack-shaped plasma on the surface of the sputter target is used as an origin point of the race. With the longitudinal direction of the track-shaped plasma as the x-axis, When the direction perpendicular to the x-axis on the surface of the magnetic target is the y-axis, the x-axis length of the magnetic field generating means differs from the x-axis length of the magnetic field generating means in the y-axis direction. A magnetron sputtering apparatus, wherein the magnetic field according to claim 1 is obtained by using a solid body. 3. A sputter target in a vacuum container, and a mechanism for disposing a substrate on which a film is to be deposited at a position facing the sputter target, wherein the magnetron magnetic field is formed on the surface of the sputter target. A magnetic field generating means by a permanent magnet movable parallel to the sputter target surface is provided in the vacuum container or outside the vacuum container, and a DC voltage or an AC voltage is applied to the sputter target to thereby form the sputter target surface. In a magnetron sputtering apparatus for generating a racetrack-shaped plasma that is geometrically point-symmetrical and long in one direction to deposit a film on the substrate, the racetrack-shaped plasma on the surface of the sputter target is used as an origin point of the race. With the longitudinal direction of the track-shaped plasma as the x-axis, The magnetic field according to claim 1, wherein a magnetic body is attached to a surface of the outer peripheral portion of the magnetic field generating means that intersects perpendicularly to the x-axis when the direction perpendicular to the x-axis on the target surface is the y-axis. A magnetron sputtering device characterized by.