CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from Japan Patent Application No. 2019-084707, filed on Apr. 25, 2019, and Japan Patent Application No. 2020-062178, filed on Mar. 31, 2020, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present disclosure relates to a film formation apparatus and film formation method.

BACKGROUND

Silicon (Si) films applied for optical films, etc., should be made as Si—H films (referred to as hydrogenated silicon films below) having undergone hydrogen termination by coupling hydrogen (H) atoms to dangling bonds for achieving a stabilized state since it becomes electrically and optically unstable if an dangling bond is present in a silicon atom in a film. An example film formation apparatus that forms silicon films is an apparatus that deposits silicon particles on a substrate by sputtering. The silicon to be deposited by sputtering is an amorphous material (amorphous) which has more dangling bonds than crystalline silicon, can be stabilized by performing hydrogen termination.

According to such a film formation apparatus, the substrate is supported and fixed to a position facing the target of a silicon material within a chamber that is a gas-tightly sealed container. Next, a sputter gas to which a hydrogen gas is added is introduced in the chamber, and high-frequency power is applied to the target to produce a plasma sputter gas. Active species produced by plasma beat out the silicon particles from the target, and such particles are deposited on the substrate. At this time, coupling of the dangling bonds of the silicon atoms to the hydrogen atoms contained in the sputter gas causes a hydrogen termination.

When the hydrogen termination is performed together with the film formation as described above, a coupling efficiency between silicon and hydrogen is not excellent. Hence, it is necessary to increase the ratio of the hydrogen gas (a hydrogen concentration) in the sputter gas. When, however, the hydrogen concentration is increased, a possibility of explosion when high-concentration hydrogen reacts with oxygen in the film formation apparatus and due to heat increases. Accordingly, when the hydrogen concentration is to be increased, explosion-proof structures are added to a building and to an apparatus so as to ensure the safety. Consequently, the costs of facilities increase. Moreover, the silicon atoms in the surface layer of the silicon film formed on the substrate is likely to be hydrogen terminated when a film formation is performed with a sputter gas that contains a hydrogen gas within a chamber. However, the hydrogen atoms is difficult to reach inside of the silicon film, so some dangling bonds of the silicon atoms inside the silicon film are likely to be left. That is, it is difficult to perform hydrogen termination efficiently on the entire silicon film including the inside thereof.

The present disclosure has been proposed in order to address the above-described technical problems, and an objective is to provide a film formation apparatus and a film formation method capable of forming a hydrogenated silicon film efficiently at low costs.

SUMMARY OF THE INVENTION

In order to accomplish the above objective, a film formation apparatus according to the present disclosure includes:

a carrying unit that includes a rotation table which circulates and carries a workpiece;

a film formation process unit which includes a target formed of a silicon material, and a plasma producer that produces plasma of a sputter gas introduced between the target and the rotation table, and which forms a silicon film on the workpiece by sputtering; and

a hydrogenation process unit which includes a process gas introducing unit that introduces a process gas containing a hydrogen gas, and a plasma producer that produces plasma of the process gas, and which performs hydrogenation on the silicon film formed on the workpiece,

in which the carrying unit carries the workpiece so as to alternately pass through the film formation process unit and through the hydrogenation process unit.

A film formation method according to the present disclosure comprising:

a circulating and carrying process in which a carrying unit including a rotation table circulates and carries a workpiece;

a film formation process in which a film formation process unit comprising a target formed of a silicon material, and a plasma producer that produces plasma of a sputter gas introduced between the target and the rotation table, forms a silicon film on the workpiece by sputtering; and

a hydrogenation process in which a hydrogenation process unit comprising a process gas introducing unit that introduces a process gas containing a hydrogen gas, and a plasma producer that produces plasma of the process gas, performs hydrogenation on the silicon film formed on the workpiece,

wherein the carrying unit carries the workpiece so as to alternately pass through the film formation process unit and through the hydrogenation process unit.

According to the present disclosure, efficient formation of hydrogenated silicon films at low costs is enabled.

