JPH02254161A - Ecr sputtering device - Google Patents

Abstract

PURPOSE:To obtain ion assistant effect without connecting the other bias power source to a base plate by providing both a third electrode placed in the position brought into contact with plasma and a power source connected thereto and changing the voltage of the third electrode. CONSTITUTION:This ECR sputtering device is formed of a cavity 2, the magnetic field generating sources 3 for an electron cyclotron provided around it, a vacuum chamber 6, a first electrode 7, a second electrode 5, a third electrode 8 and a power source 9 connected to the third electrode 8. The above-mentioned cavity 2 is provided to the introduction port of a micro semiconductor waveguide 1. Further a base plate is fitted to the first electrode 7 and a target is fitted to the second electrode 5. Furthermore the third electrode 8 is provided in the position brought into contact with plasma. Then the electric potential of this plasma is regulated.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is directed to an ECR (ECR) equipped with an ion assist function (forming a film by hitting deposited particles with ions) that can form a dense, high-quality thin film. This invention relates to an electron cyclotron resonance type (electronic cyclotron resonance type) spackling device.

[Conventional technology]

In film formation by sputtering, the purpose is to apply a bias voltage to the coated substrate to form a film in the micropores of the coated substrate, and to increase the adhesion of the film on the coated substrate -1-. There is some biased battering going on.

Recently, attempts have also been made to form a special functional film using the ion auxiliary effect of a substrate using argon (A1) or the like.

In conventional ECR sputtering, 1. Argon ions in the plasma generated by microwaves, magnetic fields, and argon gas are accelerated by applying a negative high voltage to the target layer (second electrode) and collide with the target.
The sputtered particles reach and deposit on the grounded substrate (first electrode). At this time, if the substrate and the target material are conductive and the substrate is at ground potential, the ions will not reach the substrate and the ion assist effect will hit the deposited particles. I can't wait for IJ. Therefore, in order to obtain the ion assist effect, the substrate (first electrode) must be at a negative potential. This is called a bias potential.

On the other hand, if the substrate or target is a dielectric, the electrons reaching the substrate generate a negative potential (self-bias) at 4tL, producing the same effect as when a bias is applied to the substrate.

[Problem to be solved by the invention]

However, the self-bias in conventional ECR spackle has the disadvantage that it is difficult to adjust it from the outside and the acceleration energy of the assisting ions cannot be controlled.

In addition, if the substrate is in the form of a film or if the structure is complicated such as substrate rotation or substrate lifting, a high frequency shield, etc. is required to apply a bias potential to the substrate, such as a slip ring or when using an insulated RF bias power supply. , and structurally 1. There were some drawbacks.

The present invention was made to solve the drawbacks listed in item L, and by controlling the plasma potential without connecting a bias power source to the substrate, it can exhibit the same effect as when applying a bias. The object of the present invention is to obtain an ECR sputtering apparatus that can form a high-quality thin film by ion assisting.

[Failure to solve the problem]

The ECR sputtering apparatus according to the present invention includes a third electrode provided at a position in contact with plasma, and a power source connected to the third electrode.

[For production]

By changing the voltage of the third electrode, the potential of the plasma can be adjusted.

〔Example〕

Next, before describing embodiments of the present invention, the basic knowledge of the present invention will be explained.

FIGS. 2(a) and 2(b) are explanatory diagrams showing the relationship between the substrate high-atomization level and the plasma potential. Here, the same figure (
a) shows a conventional ECR sputtering device;
b) shows the ECR sputtering apparatus of the present invention.

In the figure, ■, is the ground potential, ■, is the substrate potential, VT
is the target potential, ■ is the plasma potential, EA is the assist energy, and E is the sputtering energy.

Now, in FIG. 2(a), since the plasma potential is approximately the ground potential, the argon ion (A ) is the acceleration energy. Therefore, when a bias voltage is applied to the substrate (first electrode), the difference between the substrate potential V and the plasma potential (earth potential Vt) becomes the energy EA for hitting the substrate (ion assist).

On the other hand, in FIG. 2(b), a third electrode is provided at a position in contact with the plasma generated in the cavity, a positive potential is applied to this electrode, and the substrate is brought to the ground potential (2). shall be. As a result, since plasma can be regarded as a conductor, the plasma potential (2) rises to the positive potential given by the third electrode.

In addition, in the case of constant current discharge, the discharge impedance is constant and the sputtering energy does not change, but the apparent discharge impedance (earth potential V
, and the target potential V□) decreases. Same figure (b)
indicates this relationship.

Therefore, even if the substrate potential is left as the ground electrode, the plasma potential, that is, the potential of the third electrode becomes the acceleration energy of the ions hitting the substrate (ion assist 1 - energy EA), which is equivalent to applying a bias voltage to the substrate. This will have the effect of

That is, the substrate (first electrode) is not connected to a bias power source and is kept at ground potential, and the third electrode can be adjusted to provide an ion assist function, thereby simplifying the apparatus.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an ECP sputtering apparatus showing an embodiment of the present invention.

In the figure, 1 is a microwave (e.g. 2.45 G
Hz) waveguide, 2 a cavity for ionization, 2 a the opening of the cavity 2, 3 a solenoid coil for electronic zaik provided around the cavity 2, 4 the cavity and the vacuum chamber. 5 is a truncated conical cylindrical target (second electrode) provided near the outer periphery of the open ID portion 2a.
, 6 is a vacuum chamber, 7 is a coating substrate (first electrode), 8 is a third electrode according to the present invention, and 9 is provided so that the third electrode 8 has a positive potential with respect to the ground. A plasma drawing power supply, 10, a DC (direct current) power supply provided so that the target has a negative potential with respect to the ground;
11 is an argon gas supply pipe, 12 is a cooling water supply pipe,
13 is a cooling water drain pipe, and 14 is an exhaust port connected to a vacuum pump (not shown).

Next, the film forming operation of the ECR sputtering apparatus will be explained. First, argon (Ar) gas is supplied into the cavity 2 from the supply pipe 11 . Next, by applying microwaves (frequency 2.45 GH2) through the waveguide, the electrons e within the cavity begin circular motion within the cavity 2 due to the electromagnetic field caused by the solenoid coil 3 and the microwave.

By these electrons, argon is excited to Ar'' and e-.At this time, if the rotation period of the electron is Wc, then Wc=Z
It can be expressed as eB/mc. However, Ze is the electric charge of the electron, B is the magnetic flux density, m is the mass, and C is the speed of light. As a result, plasma is generated within the cavity 2.

Next, a positive voltage is applied to the third electrode 8 by the power source 9. This increases the plasma potential to the positive side,
Plasma is emitted from the opening 2a connected to the chamber 6, which is at ground potential.

Then, some of the positive ions are accelerated by the negative voltage of the power source 10 applied to the target 5 and sputter the target 5. At this time, the energy for sputtering the target 5 can be adjusted by the power source 10.

On the other hand, the remaining positive ions (Ar") that did not sputter Kugeso 1-5 reach the chamber 6 where they hit the substrate 7 as assist effect ions. At this time, the energy of the positive ions hitting the substrate 7 is equal to the plasma potential. It is determined by the difference from the ground potential, that is, the voltage of the plasma extraction power source 9 applied to the third electrode 8.

In this manner, the ECR sputtering apparatus of this embodiment can sputter the target 5 with some of the positive ions emitted from the cavity 2, and can prevent excess positive ions from reaching the substrate 7 for assisting purposes.

In addition, since each power source can be adjusted independently, the energy of sputtered ions, energy, and assist ions
The number of sputter ion particles and the number of assist ion particles can be controlled independently.

Another method of using the ECR sputtering apparatus in this embodiment is active sputtering of a TiN film or the like. This is a method in which an active gas is introduced into plasma to react with sputtered atoms to form a thin film of a compound different from the material of the target 5. The requirement for this compound thin film to be made is that the positive ions in the plasma are excited to the highest energy among the excited states. In some cases, one electron in the outermost shell is removed and an atomic or molecular orbital with a stronger combining force is taken.

In the above embodiment, the third electrode was provided at a position in contact with the plasma, but the cavity itself may be insulated from others and used instead of the third electrode.

In addition, in the above embodiment, the power supply 10 is powered by DC (direct current).
Although a power source is used, an RF (radio frequency) power source may also be used.

Further, in the above embodiment, the target 5 has a truncated conical cylinder shape, but it may have a flat plate or a cylindrical shape.

〔Effect of the invention〕

As explained above, the present invention has excellent effects including the following.

(1) Since the plasma potential is controlled by the voltage applied to the third electrode to obtain assist efficiency,
It is possible to obtain the ion assist effect using a bias power supply and ivy with a simple device without connecting a separate bias power supply to the substrate.

(2) Even if the substrate is a dielectric, the assist effect can be obtained with a DC (direct current) power source. However, if charge-up of the substrate becomes a problem, it is necessary to install a neutralizer near the substrate to neutralize ions.

(3) Some of the positive ions emitted from the cavity can sputter the target, and the remaining positive ions can reach the substrate as assisting ions.

Therefore, the energy of sputtered ions, the energy of assist ions, the number of sputtered particles, and the number of assist particles can be independently controlled.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an ECR sputtering apparatus showing an embodiment of the present invention, and FIGS. 2(a) and 2(b) are explanatory diagrams showing the relationship between substrate bias potential and plasma potential. DESCRIPTION OF SYMBOLS 1... Waveguide, 2... Cavity, 2a... Opening, 3... Soled coil for electron cyclotron, 4...
... Insulator, 5... Teru (second electrode), 6...
Vacuum chamber, substrate (first electrode), 8... third
Electricity...Plasma drawing power supply, 10. (DC) power supply. Noino I・7・・Koku, 9 DC

Claims (1)

[Claims] A cavity provided at an inlet of a micro semiconductor waveguide, a magnetic field generation source for an electron cyclotron provided around the cavity, and a vacuum chamber provided in communication with the cavity. In an ECR sputtering apparatus that is composed of a first electrode to which a substrate is attached and a second electrode to which a target is attached, a third electrode is provided at a position in contact with the plasma, and a third electrode is connected to the third electrode. 1. An ECR sputtering apparatus characterized in that an ECR sputtering apparatus is provided with a power source, and the potential of the plasma can be adjusted.