JPH06101036A - Ion assist control type sputtering method - Google Patents

Abstract

PURPOSE:To obtain the state of film formation practically free from peeling and increased in hardness. CONSTITUTION:An ion assist control type sputtering device is used, and, at the beginning of the initiation of sputtering, the negative numerical value of the coil exciting current of a magnetic polar body 6 on the rear of a target 2 and/or substrate bias voltage is decreased to decrease the negative numerical value of ionic current density. With the lapse of time, sputtering is done so that the negative numerical value of ionic current density is increased by performing sputtering while increasing the negative numerical value of coil exciting current and/or substrate bias voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion assist control type sputtering method capable of changing a coil exciting current and a substrate bias voltage.

[0002]

2. Description of the Related Art Conventionally, an ion assist control type sputtering apparatus in which a magnetic pole body capable of changing a coil exciting current is arranged on the back surface of a target and a substrate is held by a substrate holder capable of changing a substrate bias voltage facing a target, It is developed by the present applicants.

[0003]

By the way, as a result of various experiments, when the magnitude of the coil exciting current and / or the negative value of the substrate bias voltage is changed, the negative value of the ion current density and the magnitude of the ion flux ratio are changed. It was found that the hardness of the film formed on the substrate changed as a result. Therefore, when using the formed substrate as a material for a cutting tool, the negative value of the ion current density should be increased in order to increase the hardness of the film. It was found that, as a general tendency, the adhesive force of the film was decreased and the film was easily peeled off, as a general tendency. With this, it cannot serve as a cutting tool. Therefore, it was an object to obtain a film formation state in which the film has a strong adhesive force such that it does not come off and the film hardness is also large.

[0004]

In the present invention, an ion assist is provided in which a magnetic pole body capable of changing a coil exciting current is arranged on the back surface of a target, and a substrate is held by a substrate holding portion which can face a target and can change a substrate bias voltage. At the beginning of sputtering, the negative value of the coil exciting current and / or the substrate bias voltage was reduced to decrease the negative value of the ion current density using a controlled sputtering device. The negative value of the voltage was increased and the sputtering was performed so that the negative value of the ion current density was increased.

[0005]

[Operation] At the beginning of sputtering, the negative value of the ion current density is reduced by decreasing the coil exciting current so that the hardness of the film is relatively small but the adhesive force of the film is extremely large. The film is formed in a state where it is hard to peel off. After that, the negative value of the ion current density is gradually increased or gradually increased, and finally, the negative value of the ion current density is kept large, and a film with high hardness is formed on the surface and near the surface. To do.

[0006]

EXAMPLE FIG. 1 shows an ion-assisted control type sputtering apparatus, in which 1 is a vacuum chamber, 2 is a target, and 3 is a target.
Is a target holder, 4 is a substrate facing the target 2, 5 is a substrate holder, 6 is a magnetic pole body provided on the back surface of the target 2, and the magnetic pole body 6 is an inner magnetic pole 7, a yoke 8, an outer magnetic pole. The coil exciting current can be changed appropriately. Reference numeral 10 is a control device that can change the coil exciting current and the substrate bias voltage. Of course, the control device 10 is equipped with a power supply for the coil exciting current and the substrate bias voltage.

When the magnitude of the negative numerical value of the coil exciting current and / or the substrate bias voltage is changed using this apparatus, the magnitude of the negative numerical value of the ion current density changes accordingly.
Also, the hardness of the film changes depending on the negative value of the ion current density. However, the magnitude of the adhesive force of the film changes depending on the hardness of the film. That is, if the negative value of the ion current density is large, the hardness of the film is large and the adhesive force of the film is small. Conversely, if the negative value of the ion current density is small, the hardness of the film is small and the film hardness is small. The adhesive force of is increased.

Next, an experimental example will be shown. First, when the relationship between the coil exciting current and the substrate bias voltage and the ion current density or the ion flux ratio was confirmed, it was found that the result was as shown in FIG. However, in this case, when the coil exciting current is initially set to 0 A, the exciting strengths of the S pole and the N pole of the magnetic pole body 6 are made equal, and the magnetic force lines are all from the N pole to the S pole.
If the coil excitation current is increased to, for example, 10 A after making a closed system that goes to the pole, the excitation strength of the S pole becomes larger than the excitation strength of the N pole, and the weak magnetic field line changes from the N pole to the S pole. An apparatus was used in which all the magnetic field lines went, but the remaining magnetic field lines went from the S pole to the upper side where the substrate 4 was located. It can be seen from FIG. 2 that the negative value of the ion current density increases from about 1 to about 7 when the coil exciting current increases stepwise from 0A to 16A. (Actually, the ion current density decreases from -1 to -7.) Also,
It can be seen that as the negative value of the substrate bias voltage increases, the negative value of the ion current density increases slightly in proportion.

Further, the relationship between the ion current density and the hardness of the film is somewhat different depending on the magnitude of the substrate bias voltage,
For example, it turned out that it is as shown in FIG. It can be seen from FIG. 3 that the hardness of the film increases almost linearly as the negative number of the ion current density increases.

When forming a film, the relationship obtained in FIGS. 2 and 3 is used to form the film, for example, as shown in FIG. That is, at the beginning of the sputtering, the negative value of the ion current density is reduced by decreasing the coil exciting current, and the coil exciting current is gradually or gradually increased over time. The negative number of the ion current density is gradually increased as shown by the three solid lines or gradually increased as shown by the dotted lines. After a certain period of time, sputtering is performed with the coil exciting current kept constant. In this case, since the ion current density is relatively small at the beginning, the strength of the film is slightly decreased, but the adhesive force of the film is increased and the film is less likely to come off. Finally, since the ion current density is increased and the sputtering is performed, the desired hardness is sufficiently obtained on the surface of the formed film. As a result, as a whole, a film-forming state was obtained in which peeling was difficult and the hardness was sufficient.

The control of the coil exciting current and the ion current density is not limited to the state shown by the solid line or the dotted line in FIG. 4, but may be increased by a steep gradient at the beginning, and a gentle gradient from the middle. You can choose. Further, the hardness of the film can be controlled by appropriately changing the flow rates of the sputtering gas such as argon gas and the reactive gas such as nitrogen gas and oxygen gas, which are introduced into the vacuum chamber 1.

[0012]

As described above, in the present invention, the magnetic pole body capable of changing the coil exciting current is arranged on the back surface of the target,
Using an ion-assisted control type sputtering device that holds the substrate in the substrate holding part that can change the substrate bias voltage facing the target, reduce the negative values of the coil exciting current and / or the substrate bias voltage at the beginning of sputtering. Since the negative value of the ion current density is made smaller and the negative value of the coil excitation current and / or the substrate bias voltage is made larger later, the sputtering is performed so that the negative value of the ion current density becomes larger. It is possible to easily and easily obtain a film that has a large adhesion force, is hard to peel off, and has a high hardness on the surface.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view showing one embodiment of an apparatus for carrying out the present invention.

FIG. 2 is a diagram showing an example of a relationship between a substrate bias voltage and an ion current density.

FIG. 3 is a diagram showing an example of the relationship between ion current density and film hardness.

FIG. 4 is a diagram showing an example of the relationship between film formation time, ion current density, and film hardness.

[Explanation of symbols]

 1 vacuum chamber 2 target 4 substrate 5 substrate holder 6 magnetic pole body 7 inner peripheral magnetic pole 9 outer peripheral magnetic pole 10 controller

Claims (1)

[Claims] 1. Sputtering is performed using an ion-assisted control type sputtering apparatus in which a magnetic pole body capable of changing a coil exciting current is arranged on the back surface of a target, and a substrate is held at a substrate holding portion capable of changing a substrate bias voltage facing a target. At the beginning of the operation, the negative values of the coil exciting current and / or the substrate bias voltage were reduced to decrease the negative values of the ion current density, and the negative values of the coil exciting current and / or the substrate bias voltage were increased later. An ion assisted control type sputtering method in which sputtering is performed so that the negative value of the ion current density is increased.