JPH0499268A - Sputtering system - Google Patents

Abstract

PURPOSE:To prevent the intrusion of impurities into the deposited film on the surface of a substrate and to improve the quality of the film by setting an exhaust chamber communicating with a vacuum vessel and providing a cathode formed by a getter in the chamber. CONSTITUTION:A substrate is mounted on a substrate holder 3, a vacuum vessel 1 is filled with a specified atmosphere, a DC power source 12 is turned on to impress a voltage on a target 2, hence the target 2 is sputtered, and the thin film of the sputtered particles is formed on the substrate. A DC power source 17 connected to the cathode 16 is also turned on at the same time that the power source 12 is turned on to impress a voltage on the cathode 16. Since the exhaust chamber 13 contains the same atmosphere as that in the vessel 1, an electric discharge is generated between the cathode 16 and the opposed wall of the chamber 13, the cathode 16 is sputtered in the chamber 13, and an active film 18 is formed on the wall opposed to the cathode 16 having the active particles of the getter constituting the cathode 16. Since the active gas remaining in the chamber 13 and vessel 1 is evacuated by the active film 18, an impurity gas (active harmful to the thin film formed on the substrate is collected and removed, and the intrusion of the impurity into the substrate side is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a sputtering apparatus that also has the ability to exhaust impurity gas.

(Prior Art) A typical conventional sputter link device has the configuration shown in FIG. That is, the target 22 and the substrate holder 23 were disposed facing each other in the vacuum container 21, and the vacuum container 21 was connected to the V[quick 24 and the waste introduction system 25]. The exhaust system 24 is composed of a roughing pump (for example, an oil rotary pump) 26 and a main pump (for example, a cryopump) 27 as exhaust means, and is composed of piping 28, a valve 29, and a main valve 30, while the gas introduction system 25 is It was common to have a barrier pull leak valve 30 and an inert gas (for example, argon gas) cylinder 3]. Further, a negative high voltage was applied to the target 22 by a DC power supply 32.

In such a device, the substrate (
When sputtering the material of the target 22 to form a thin film on the surface of the target (not shown), the following procedure was used.

That is, first, the valve 29 of the exhaust system 24 is operated to evacuate the inside of the vacuum container 2 to a low vacuum region using the roughing pump 26, and then the two valves and the main valve 33 are operated to switch the evacuation means to the main pump 27. Switch to evacuate to high vacuum area.

Next, an inert gas is introduced into the vacuum container 21 from the gas introduction system 25, and a negative high voltage is applied to the target holder 22 to cause a discharge between the target holder 22 and the substrate holder 23. 22 is sputtered, and the sputtered target material is deposited on the surface of the substrate supported by the substrate holder 23 to form a thin film.

(Problems to be Solved by the Invention) Sputtering apparatuses as described above are used in various fields including, for example, the manufacturing process of semiconductor devices. As the pattern of the formed thin film becomes finer,
There is also a growing demand for improved properties of films formed by sputtering. Therefore, it has become necessary to remove impurity gases during sputtering as much as possible, which have a large effect on film quality.

For example, in the manufacture of semiconductor devices, when forming films for aluminum wiring using sputter links, it has been pointed out that if a large amount of impurity gas components (N2, H, O) are mixed in, the life of the wiring will be shortened. There is.

However, the above-mentioned sputter link apparatus has a problem in that the impurity gas cannot be effectively exhausted due to the exhaust system. That is, during sputtering, that is, during the introduction of an inert gas, a pumping action is required to improve the ability to exhaust impurity gas, but due to the characteristics of the crystal vacuum pump used as the main pump 27, when the operating pressure is high. (
During sputtering, when the vacuum is low (usually around 10 mTorr), the pumping speed decreases and the pump is down, so it is recommended to reduce the conductance of the main valve 33 between the vacuum chamber 21 and the main pump 27 while allowing the sputtering to proceed. It was normal. For this reason, the ability to exhaust impurity gas is also reduced by throttling the main valve 33, causing the impurity gas to become a residual gas and to be mixed into the thin film.

The present invention has been made in view of the above-mentioned problems in exhausting impurity gases, and an object of the present invention is to provide a sputtering apparatus that can exhaust impurity gases during sputtering.

(Means for Solving the Problems) A sputtering apparatus of the present invention that achieves the above object includes a target and a substrate holder installed in a vacuum container, and an exhaust system and a gas introduction system connected to the vacuum container. The sputtering apparatus is characterized in that an exhaust chamber communicating with the vacuum chamber is installed, and a cathode made of a getter material is installed in the exhaust chamber.

It is sufficient that the vacuum container and the exhaust chamber communicate with each other so that the impurity gas can flow therethrough, but in order to increase the conductance of gas flow, they are communicated through an opening provided in the wall of the vacuum container, It is desirable that an anti-adhesive shield be placed opposite the opening.

(Function) According to the sputtering apparatus of the present invention, when a negative voltage is applied to the cathode made of the getter material in the exhaust chamber during sputtering, an inert gas discharge can also be caused in the exhaust chamber. As a result, the gettaki 4 that made up the cathode
is sputtered to form an active film of getter material on the inner wall of the exhaust chamber, and the active film captures impurity gas (active gas).
Can be removed. Since the active film does not have an exhaust effect on the inert gas introduced for sputtering, the exhaust ability is improved only for impurity gases.

(Example) The present invention will be explained below based on examples.

FIG. 1 is a diagram showing a sputtering apparatus according to an embodiment. Similar to the conventional apparatus shown in FIG. An exhaust system 4 and a gas introduction system 5 are connected to. The exhaust system 4 is composed of a roughing pump 6 and a main pump 7 as exhaust means, and a pipe 8, a valve 9, and a main valve 9.

Further, the gas introduction system 5 includes a barrier pull leak valve 10 and an inert gas cylinder 11. Further, a DC power source 12 is connected to the receiver 2.

Furthermore, an evacuation chamber] 3 is installed on the side wall of the vacuum container 1, and the evacuation chamber 13 and the vacuum container l are communicated with each other through an opening 14 on the wall side.
On the side, an anti-adhesion shield plate 15 is installed to maintain a predetermined distance from the opening 14 and to cover the opening 4. A titanium cathode 16 is installed in the exhaust chamber 13, and a DC power supply 7 for applying a negative high voltage is connected to the cathode cord 6.

When performing sputtering using the sputtering apparatus of the above embodiment, after mounting the substrate on the substrate holder 3,
The vacuum container] is evacuated to a vacuum by the exhaust system 4, and then the inert gas (for example, argon gas) from the inert gas cylinder]1 is introduced into the vacuum container 1 by the gas introduction system 5, and the main valve of the exhaust system 4 is 19 to adjust the pressure inside the vacuum container 1 to a predetermined pressure (for example, OmTorr).

After that, the DC power supply 12 is turned on and a negative high voltage is applied to the target 2 (the substrate holder 3 is at ground potential) to generate a discharge between the target 2 and the substrate holder 3, and the target 2 is As a result, a thin film is obtained by depositing sputtered particles on the surface of the substrate mounted on the substrate holter 3.

At the same time as the DC power supply 12 is turned on, in the apparatus of this embodiment, the DC power supply 17 connected to the cathode 6 is also turned on, and a high negative voltage is applied to the cathode 16. Since the exhaust chamber] 3 in which the cathode] 6 is installed has the same atmosphere as the inside of the vacuum container 1-, when a high voltage is applied to the cathode 16, discharge occurs between the cathode] 6 and the opposite wall of the exhaust chamber 13. happens.

As a result, the cathode 6 is sputtered in the exhaust chamber 3, and the titanium active particles forming the cathode 16 are formed as an active film 8 on the wall facing the cathode 16.

The active film 18 has an exhaust effect on the active residue remaining in the exhaust chamber 13 and the vacuum container 1, so it captures impurity gas (active gas) that is harmful to the thin film formed on the substrate. , can be removed to prevent contamination on the substrate side. Furthermore, since this active film 18 does not have an exhaust effect on the inert gas that is the sputtering gas, the necessary exhaust operation can be performed without affecting the sputter link conditions within the vacuum chamber 1. . Cathode] 6
Sputtered particles may also fly toward the opening 14, or because the opening 14 is provided with an anti-adhesion shield plate 5, they may fly toward the vacuum chamber 1 and enter the thin film on the surface of the substrate. There is no risk of contamination.

Although the embodiments have been explained using a two-pole DC type sputtering apparatus, other sputtering methods can be used such as two-pole or quadrupole sputtering link, magnetron sputtering, etc.
It is also possible to implement the present invention using other sputtering methods.

(Effects of the Invention) As described above, according to the present invention, an active film is formed in the exhaust chamber to exhaust impurity gas in the sputtering atmosphere, so that impurity gases in the thin film formed on the surface of the substrate can be removed. This has the effect of preventing impurities from entering the film and improving film quality.

Furthermore, if the vacuum container and the exhaust chamber are configured to communicate through the opening, the conductance for the flow of waste between the vacuum container and the U1' air chamber can be increased, and therefore the pumping speed for impurity gas can be increased. effective.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional device. 1. Vacuum container 2. Target 3. Substrate holter 4. Exhaust system 5. Gas introduction system ] 3 Exhaust chamber

Claims (1)

[Claims] 1. A sputtering apparatus in which a target and a substrate holder are installed in a vacuum chamber, and an exhaust system and a gas introduction system are connected to the vacuum chamber, and an exhaust chamber communicating with the vacuum chamber is installed. A sputtering apparatus 2 characterized in that a cathode made of a getter material is installed in the evacuation chamber.The vacuum chamber and the evacuation chamber communicate through an opening provided in the wall of the vacuum chamber, and the opening 2. The sputtering apparatus according to claim 1, wherein an anti-adhesive shield is installed opposite to the part.