JP2984746B2 - Ion beam sputtering equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion beam sputtering apparatus and, more particularly, to a technique for preventing an inert gas that has not been ionized by discharge or the like from leaking from an ion source.

[0002]

2. Description of the Related Art A typical conventional ion beam sputtering apparatus 21 is shown in FIG. A sputtering ion source 1 usually called a Kauffman-type ion source capable of obtaining a large current is arranged opposite to the target 22, and inert gas ions (usually Ar ⁺ ions) accelerated to about 1 KeV are applied to the target 22 to produce a sputtering effect. At this time, the atoms 23 constituting the target 22 are knocked out, and a film 25 is deposited on the substrate 24 arranged to face the target 22.

At this time, the film forming chamber 26 is evacuated by a vacuum pump, but the inert gas which has not been ionized leaks into the chamber 26 through the grit of the ion source 1 and the like, and usually, about 10 ⁻³ Pa (Pascal). It was difficult to get a high vacuum. The target 22 is held by a target holder 27, and the substrate 24 is held by a substrate holder 28.

Next, a conventional Kauffman-type ion source 1 will be described with reference to FIG. Upper plate 2a in cylindrical housing 2
The anode 3 and the hot cathode 4 are arranged on the bottom plate 2b side, respectively, and a voltage of several tens of volts is applied from the discharge power supply 5 between them. A current is supplied to the hot cathode 4 from a heater power supply 6 of several volts. An inert gas such as Ar is supplied from the upper plate 2a side through a gas introduction pipe 7 to a region (referred to as a plasma generation region) 10 between the anode 3 and the hot cathode 4 facing each other.
Will be introduced. The anode 3 is held at a high potential by a high-voltage power supply HP of 1000 to 2000 V. The housing 2 is connected to a high-voltage power supply HP through a resistor R, and has a slightly lower voltage than the anode during operation. A grid-like grit 12 a is attached to the opening 2 c on the side surface of the housing 2, and is maintained at substantially the same potential as the housing 2. A grid-like drawer grit 12b is arranged near the outside of the grit 12a,
It is kept at 100 to -500V.

The electrons e ⁻ generated from the hot cathode 4 are accelerated by the electric field applied between the hot cathode 4 and the anode 3, collide with, for example, Ar gas introduced from the gas introduction pipe 7, and a part of the gas is ionized. At this time, the magnetic field 9 increases the ionization efficiency. Gas ions (Ar ^{+ in} this example) generated in the plasma generation region 10 are sucked and accelerated by the grid-like extraction grit 12 b and incident on the substance in the process region 13, that is, the target 22. However, the gas ionized in the ion source 1 is only 20% or more of the supply gas, and most of the gas leaks from the extraction grit 12b to the process region 13 as a gas.

[0006] A well-known ECR (Electron Cyclotron) which is excited by microwaves to be ionized.
Resonance method or a well-known RF (Radio Frequency) which is excited by an RF wave and ionized.
In the case of the ion source using the cy) method, the ionization efficiency is the same as that of the above-mentioned Kauffman-type ion source.

[0007]

SUMMARY OF THE INVENTION Conventionally used ion sources having good ionization efficiency (Kauffman-type ion source, ECR
Ion source, RF ion source, etc.).
At about a few percent, most of the gas was flowing into the process atmosphere without being ionized. That is, if a large amount of ions are to be extracted from the ion source 1 in order to increase the sputtering rate (film forming rate), a gas that has not been ionized necessarily flows into the process atmosphere. Therefore, these gases are taken in during the film formation and deteriorate the characteristics of the film. Alternatively, when attempting to deposit a compound while introducing a reactive gas into the chamber, there has been a problem in that the unnecessary gas mixed in the chamber may change the stoichiometric value.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent the unnecessary gas that has not been ionized from leaking from an ion source and to increase the purity of a substance formed by ion beam sputtering.

[0009]

According to the present invention, as shown in FIG. 1, an ion source equipped with a mechanism for eliminating gas which does not become ions present in the ion source is provided in place of the conventional ion source. As a result, the degree of vacuum during the process is improved, unnecessary gas molecules and the like mixed into the grown film are reduced, and a high-quality film with few impurities is formed.

According to the present invention, the gas supply port of the gas introduction pipe for introducing an inert gas into the ion source casing from outside the film forming chamber is generated between the anode and the cathode in the ion source casing.
Raw gases ion passage grayed plasma generation region and the ion source
An inert gas in which the anode and the cathode travel straight between the side surface of the housing supporting the lid and the plasma generation region.
It is provided so as not to block . On the other hand, a discharge port for the inert gas that has not been ionized is provided near the side of the ion source housing facing the gas supply port. An exhaust pipe connected to an exhaust pump provided outside the film forming chamber is attached to the exhaust port, and an exhaust speed adjusting valve is provided in the exhaust pipe as necessary.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. Reference numeral 7 denotes a pipe for supplying an inert gas 8 such as argon for producing ions, which is introduced into the ion source 1. Reference numeral 24 denotes a substrate for applying a film, which is usually provided with a mechanism for heating, cooling , or rotating. Reference numeral 25 denotes a deposited film, reference numeral 23 denotes atoms sputtered out of the target 22, reference numeral 22 denotes a target serving as a raw material of a desired film, and reference numeral 26 denotes a film forming chamber, which is evacuated by a pump. Conventionally, ion source 1
A part of the Ar gas 8 introduced into the plasma is ionized by ionization in the plasma of 10, and is extracted and accelerated by the extraction grid 12b to sputter the target 22 to generate sputtered atoms 23. 24.

In the present invention, a Kauffman-type ion source, ECR
Gas supply port 7a of the gas introduction pipe 7 based on the ion source, the RF ion source and other ion sources.
Is provided between the plasma generation region 10 and the side surface of the housing around the grit 12a so as to face the plasma generation region 10, and an exhaust port 2f for gas not ionized in the plasma generation region 10 is provided with a gas supply port. It is provided near the side of the ion source housing facing the opening 7a. Also, in the exhaust port 2f,
An exhaust pipe 13 for connecting to an exhaust pump provided outside the film forming chamber 26 is attached, and the exhaust pipe is provided with an exhaust speed adjusting valve 14 as necessary.

Accordingly, a gas pressure gradient is created between the gas supply port 7a and the exhaust port 2f, and the gas that is not ionized flows into the exhaust pipe 13 along this gradient. The ionized gas is accelerated by being attracted by the electric field of the extraction grit 12b, hits the target 22, and sputters the target material as in the related art. Therefore, unnecessary gas is grit 1
The amount flowing into the film formation chamber 26 through 2b is greatly reduced, the degree of vacuum during the film formation is improved, and the amount of unnecessary gas molecules mixed into the film 25 can be reduced.

[0014]

According to the present invention, unnecessary gas partial pressure during ion beam sputtering can be reduced by providing an ion source having a mechanism for exhausting unnecessary gas that has not been ionized. As a result, impurities mixed into the film can be reduced, and a high-quality film can be formed.

When a reactive gas is introduced during film formation to deposit a compound, unnecessary gas atoms and the like mixed in the deposit can be similarly reduced, and a deposit having a correct stoichiometric value can be obtained. Can be formed.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a basic configuration diagram showing an embodiment of the ion source 1 of FIG.

FIG. 3 is a diagram showing the basic configuration of a conventional ion beam sputtering apparatus.

FIG. 4 is a diagram showing the basic configuration of the ion source 1 of FIG. 3;

Claims (2)

(57) [Claims] An ion source, a target, and a substrate are arranged in an evacuated film forming chamber, and inert gas ions from the ion source are made incident on the target to strike out atoms constituting the target, In the ion beam sputtering apparatus for depositing a film on the substrate, a gas supply port of a gas introduction pipe for introducing an inert gas into the ion source housing from outside the film forming chamber, and an anode in the ion source housing. Between the plasma generation region generated between the cathode and the housing side plate supporting the gas ion passage grid of the ion source, an inert gas that is opposed to the plasma generation region, and in which the anode and the cathode travel straight. An exhaust port of an inert gas which is provided so as not to be blocked and which is not ionized in the plasma generation region is provided on the side of the ion source housing facing the gas supply port. Provided in the vicinity of, its outlet, characterized in that the exhaust pipe for connection to an exhaust pump provided outside of the deposition chamber is mounted, an ion beam sputtering apparatus. 2. A claim in first ion beam sputtering apparatus according, the ion beam sputtering apparatus exhaust speed adjusting valve, characterized in Tei Rukoto provided in the exhaust pipe.