JPH0681145A - Magnetron sputtering device - Google Patents

Abstract

PURPOSE:To form films having uniform film quality on a substrate by disposing a target so as to incline with the substrate at the time of forming the films by a target material on the substrate by a magnetron sputtering device while moving the substrate. CONSTITUTION:While the substrate 4 for film formation is moved from a position A to a position B C within a vacuum film forming chamber 1 of the magnetron sputtering device, the films of the target 11 material are formed on the substrate 4. The target 11 is disposed to incline with the substrate 4 in such a case and a high-frequency electric power is impressed to a target electrode 3 to generate an electric discharge between the substrate 4 and a grounding plate 6 on the rear surface of the substrate 4, by which a plasma region P is generated. The plasma density on the front surface of the target 11 is increased by the magnetic lines of force (j) by magnets 14, 15 on the rear surface and largely sputtered erosion grooves (g) are formed but the target 11 is inclined with the substrate 4 and, therefore, the sputtered ions of the large kinetic force from near the erosion grooves (g) stick to the substrate 4 from a diagonal direction, thereby decreasing damages. The films uniform in a thickness direction are thus formed.

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 for forming a film while moving a substrate.

[0002]

2. Description of the Related Art There is a moving film forming system in which a substrate is formed while a substrate is moving in a space where a substrate can be sputtered in front of a target electrode.

This film forming method is suitable for forming a film on a large area substrate, and is used, for example, in an apparatus for producing an ITO film used for a thin film transistor for a liquid crystal display. FIG. 2 is a diagram showing a conventional moving film forming type magnetron sputtering apparatus. This sputtering apparatus includes a film forming chamber 1 whose inside is kept in a vacuum, and gate valves 2a and 2b between an inlet / outlet chamber (not shown) for loading and unloading a substrate, a target electrode 3 and a substrate 4 which are moved to form a film. The substrate holder 5 and the ground plate 6 facing the target electrode 3 are mainly configured.

The substrate holder 5 can be moved from a position A before the film formation is started to a position C after the film formation is completed through a position B in the film formation possible region by a transfer mechanism in the film formation chamber 1.

The target electrode 3 includes a target 11 and
A backing plate 12 which is a cooling / heat conducting material from a cooling mechanism (not shown), an electrode box 13 which holds the backing plate 12 and to which electric power is applied, an inner magnet 14 and an outer magnet 15 and a yoke 16 built in the electrode box 13. Composed of and. The inner magnet 14 and the outer magnet 15 are provided so that their polarities are opposite to each other, and the ends of both magnets on the opposite side of the target 11 are connected to a yoke 16. By this magnetic circuit, magnetic force lines j having a component parallel to the target surface are generated near the target surface.

In such a conventional sputtering apparatus,
The substrate holder 5 on which the substrate 4 is placed is transferred from the outside of the apparatus to an inlet chamber (not shown) and is evacuated therein. When the inlet chamber is in a vacuum state, the sluice valve 2a is opened and the substrate holder 5 is transported to the position A before the start of film formation. After closing the sluice valve 2a, the film forming chamber 1 is operated by a gas introduction system and an exhaust system (not shown).
The inside is adjusted to a predetermined pressure. And the target electrode 3
RF power is applied to the target electrode 3
A discharge is generated between the ground plate 6 and the ground plate 6 facing it, and a plasma region p is formed.

In this state, when the substrate holder 5 is moved from the A position to the B position to the C position, the sputtered atoms sputtered from the target 11 adhere to the substrate 4 while passing through the plasma region p on the way to form a film. To be done. Then, when the position C is reached, the RF power is stopped, the discharge is stopped, the gas introduction is stopped, the film forming chamber pressure is evacuated to a predetermined vacuum degree, and then the gate valve 2b is opened to open the substrate holder 5 Is carried out to an exit chamber (not shown). Then, after returning the outlet chamber to the atmospheric pressure, the substrate holder 5 is taken out of the apparatus and a series of film forming processes is completed.

[0008]

In the conventional magnetron sputtering apparatus, the magnetic lines of force j are generated by the magnetic circuit in the target electrode 3. When RF power is applied to generate plasma, a portion having a high plasma density is locally formed near the surface of the target under the influence of the magnetic force lines j. A part of the surface of the target 11 exposed to the high plasma density portion is more strongly sputtered than the other surface. Therefore, an erosion groove g is eventually formed in this portion while the sputter film formation is continued for a while.

Conventionally, the sputtered atoms from the erosion groove g and the sputtered atoms from the surface of the other target have similarly contributed to the film formation. That is, in FIG. 2, there is no distinction between the film formation by the sputter atoms from the erosion groove g shown by b and d parts and the film formation by the sputter atoms from other target surfaces shown in a, c and e parts. It was Therefore, when the film is formed while moving the substrate holder 5 to the A position, B position, and C position,
The films attached in parts b, c, d and e were laminated in this order.

However, it has been found that the film quality of the film formed by the sputtering atoms from the erosion groove g and the film quality of the film formed by the other sputtering atoms from the target surface are considerably different.

FIG. 4 is a view showing the distribution of the specific resistance value when the substrate is stopped at the position B facing the target and the ITO film is formed in the conventional sputtering apparatus.

According to this, I of the b and d portions, which are films formed by the sputtered atoms vertically emitted from the erosion groove g, are formed.
The specific resistance of the TO film is 6 × 10 ⁻³ Ω · cm, whereas the specific resistance of the ITO film of the c portion, which is a film due to the sputtered atoms from the periphery of the erosion groove, is 5 × 10 ⁻⁴ Ω · cm. It was cm, and it was found that the specific resistance value was different by one digit or more. In addition, etching was performed using an ITO etching solution (IS-2 manufactured by Sasaki Chemicals Co., Ltd.) at a liquid temperature of 40 ° C., and the etching rate was examined.
Etching rate of TO film is 40 Å / min
On the other hand, the etching rate of the ITO film by the sputtered atoms from the center of the target was 400 Å / min, which was also found to be very different.

It is considered that this difference in film quality is due to the fact that sputtered atoms and sputtered ions near the erosion groove g have larger kinetic energy than sputtered atoms from other regions. That is, since the sputtered atoms from the vicinity of the erosion groove g are sputtered violently and have a large kinetic energy, they collide violently when they are attached to the substrate, causing damage to the underlying film that has just been attached and degrading the film quality. This is probably because Therefore, there is a problem that the film quality becomes non-uniform in the depth direction when the film is moved and formed by the apparatus of FIG. That is, as shown in FIG. 3, if moving film formation is performed, each point on the substrate 4 is a,
Since it passes through parts b, c, d, and e in order,
After the layer is formed, the second layer by the part b is laminated thereon, and the third layer by the part c and the fourth layer by the part d are formed thereon.
The fifth layer including the layer e and the portion e is stacked. Of these, b
The second and fourth layers by the d part and the first by the a, c, and e parts,
The film quality of the third and fifth layers is different.

A film that is not uniform in the depth direction is difficult to control the film resistance value and the etching time at the time of making a device, which causes a device failure.

An object of the present invention is to provide a sputtering apparatus capable of forming a film having a uniform film quality without causing such unevenness of the film quality in the depth direction.

[0016]

The present invention, which has been made to solve the above problems, provides a moving film forming type magnetron sputtering apparatus which conveys a substrate and performs a film forming process on the substrate by a magnetron sputtering method. It is characterized in that the target is installed so as to be inclined with respect to the substrate, whereby damage caused by adhesion of sputtered atoms or sputtered ions having large kinetic energy from the erosion region formed on the target to the substrate is mitigated.

The operation of the sputtering apparatus having this structure will be described below.

[0018]

In the sputtering apparatus of the present invention, the surface of the target is installed not in parallel to the substrate but in an inclined state. Therefore, sputtered atoms having a large kinetic energy vertically radiated from the vicinity of the erosion groove collide with the substrate in an oblique direction, and damage to the film surface just attached is reduced. For example, when the substrate and the target are installed at an angle X, the mass of sputtered atoms vertically radiated from the target at a velocity V is M, and the component of the velocity of sputtered atoms perpendicular to the substrate is VCOS X. When the sputtered atoms adhere to the substrate, the collision energy UVERT of the formula (1) is given in the direction perpendicular to the substrate.

UVERT = MV ² COS ² X / 2 (1) Comparing the inclination angle (X) of the substrate and the target of 45 degrees with this equation and the case of 0 degrees, that is, parallel, 45
The collision energy UVERT will be halved at the same time. Therefore, as a result of reducing the damage to the underlying film,
The difference in film quality becomes small and uniform film formation becomes possible.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an example of a sputtering apparatus according to the present invention. In the figure, the same parts as those of the conventional device of FIG. In this magnetron sputtering apparatus, the target electrode 3 is arranged so as to be inclined with respect to the substrate holder 4. Then, inside the target electrode 3, an inner magnet 14 and an outer magnet 15 are provided in the same manner as in the conventional device, whereby magnetic force lines j having a component parallel to the surface of the target 11 are generated near the surface of the target 11.

In the sputtering apparatus having the above structure,
The substrate holder 5 on which the substrate 4 is placed is transferred from the outside of the apparatus to an inlet chamber (not shown) and is evacuated therein. When the inlet chamber is in a vacuum state, the sluice valve 2a is opened and the substrate holder 5 is transported to the position A before the start of film formation. After closing the sluice valve 2a, the film forming chamber 1 is operated by a gas introduction system and an exhaust system (not shown).
The inside is adjusted to a predetermined pressure. And the target electrode 3
RF power is applied to the target electrode 3
And a ground plate 6 generate a discharge, and the plasma region p
Is formed. A portion having a high plasma density is locally formed near the surface of the target 11 under the influence of the magnetic force line j. A part of the surface of the target 11 exposed to the high plasma density portion is more strongly sputtered than the other surface. Therefore, an erosion groove g is eventually formed in this portion while the sputter film formation is continued for a while. The sputtered atoms from the erosion groove g are sputtered violently and have a large kinetic energy.

In this state, when the substrate holder 5 is moved from the position A to the position B to the position C, the sputtered atoms adhere to the surface of the substrate 4 while the substrate 4 is passing through the plasma region p.

At this time, since the sputtered atoms are obliquely attached to the substrate, the damage to the film just attached is small. Therefore, even if sputtered atoms or sputtered ions having large kinetic energy emitted from the vicinity of the erosion groove g are attached to the substrate, damage is reduced,
There is no difference between the film quality and the film quality due to the attachment of sputtered atoms from other regions. That is, the erosion groove g shown in FIG.
B, d due to sputtered atoms or sputtered ions from the vicinity
The film quality of the film in the area is a, c, due to sputtered atoms or sputtered ions from other regions due to the reduction of damage.
There is no difference from the film quality of the film in the part e.

Therefore, even when the moving film is formed, a uniform film is formed in the depth direction.

Regarding the tilt angle X between the substrate and the target, the larger the tilt angle is, the more the damage due to the collision of the sputtered atoms is reduced, but at the same time, the film forming speed is also decreased. The angle is preferably around 45 degrees.

In this embodiment, the target is a target which is inclined in one direction with respect to the substrate, but the target is not limited to this shape. For example, the target may be provided in a V shape as shown in FIG. In short, sputtered atoms or sputtered ions having a large kinetic energy radiated from the vicinity of the erosion groove g may hit the substrate obliquely.

Although the present invention has been described with respect to the film quality of the ITO film, other types of films can be considered in the same manner, and it is possible to form a uniform film by reducing damage due to sputtered atoms from the vicinity of the erosion groove. it can.

The power source of the sputtering apparatus according to the present invention is not limited to the RF power source, but may be a DC power source.

[0030]

As described above, according to the present invention,
By arranging the target so as to be inclined with respect to the substrate, sputtered atoms or sputtered ions having large kinetic energy from the vicinity of the erosion groove are obliquely attached to the substrate to reduce damage. As a result, even when the transfer film formation is performed, layers having different film qualities are not formed, and uniform film formation is possible. Moreover, since the damage is reduced, the film quality is also improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a film forming chamber of a sputtering apparatus that is an embodiment of the present invention.

FIG. 2 is a sectional view of a film forming chamber of a conventional sputtering apparatus.

FIG. 3 is a cross-sectional view in the depth direction of a film formed by moving and forming by a conventional sputtering device.

FIG. 4 is a diagram showing a distribution of specific resistance values when an ITO film is formed by stopping a substrate at a position facing a target in a conventional sputtering apparatus.

FIG. 5 is a sectional view of a film forming chamber of a sputtering apparatus that is another embodiment of the present invention.

[Explanation of symbols]

 1: Film forming chamber 3: Target electrode 4: Substrate 5: Substrate holder 6: Earth plate 11: Target 14: Inner magnet 15: Outer magnet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichiro Ishida 1 Nishinokyo Kuwabara-cho, Nakagyo-ku, Kyoto City, Kyoto Prefecture Shimadzu Corporation Sanjo Factory

Claims (1)

[Claims] 1. In a magnetron sputtering apparatus of a moving film forming system for carrying out a film formation process by a magnetron sputtering method on a substrate while transporting the substrate, the target is formed by tilting the target with respect to the substrate. The magnetron sputtering apparatus is characterized in that damage caused by adhesion of sputtered atoms or sputtered ions having a large kinetic energy from the erosion region to the substrate to be absorbed is reduced.