JP2550559B2 - Carbon thin film forming equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to an apparatus for forming a carbon thin film on a substrate by a reactive sputtering method, and in particular, graphite is sputtered with an inert gas, and then graphite particles are subjected to hydrogen plasma. The present invention relates to a carbon thin film forming apparatus for decomposing and forming a film.

B. SUMMARY OF THE INVENTION The present invention provided with a target holder and the counter electrode of the magnetron for holding the target to face to the vacuum chamber, provided with a substrate holder for holding a substrate above the counter electrode, H ₂ gas atmosphere In a device for applying a high-frequency voltage between a target holder and a counter electrode to form a carbon thin film on a substrate arranged on a substrate holder, the vacuum chamber is partitioned by a plate-like electrode having a flow hole.
A section and a second section are provided, the target holder and the counter electrode are arranged in the first section, and an inert gas can be introduced, and the substrate holder is arranged in the second section, and the substrate holder and the plate-like member are arranged. By applying a high-frequency voltage between the electrode and the H ₂ gas in the two compartments, the primary plasma species generated by sputtering in the inert gas atmosphere in the first compartment were treated with hydrogen plasma. By decomposing to form active species, so that a dense thin film containing no excess hydrogen can be formed at a high speed on the substrate.

C. Conventional Technology FIG. 4 shows a conventional carbon thin film forming apparatus. In the figure, 2 is a container made of metal, and this container 2 is provided with a gas inlet 3 on its side and a vacuum suction port 4 on its bottom.
A vacuum chamber 1 is formed inside thereof. Gas inlet 3
Is connected to an external hydrogen gas tank 14 via a mass flow controller 15 by an air supply pipe. A magnetron-type target holder electrode 5 equipped with an electromagnet 9 is provided at a substantially central portion of the vacuum chamber 1, and a disc-shaped graphite target 6 is held above the magnetron-type target holder electrode 5. The target holder electrode 5 is connected to an external high frequency power supply 7 via a matching box 8. 10 is an insulating member. A circular counter electrode 11 is installed above the graphite target 6 so as to concentrically face the graphite target 6, and a high frequency voltage is applied between them. A substrate holder 12 is installed above the counter electrode 11, and a substrate 13 on which a carbon thin film is to be formed is attached to the lower surface of the substrate holder 12.

When a carbon thin film is formed on the substrate 13 using this apparatus, a high-frequency voltage is applied between the target holder electrode 5 and the counter electrode 11 while the vacuum chamber 1 is in a low-pressure hydrogen gas atmosphere. In this case, the graphite target 6 as a carbon source on the target holder electrode 5 is evaporated, diffused by the action of hydrogen plasma and adhered on the substrate 13 to form a carbon thin film.

D. Problems to be Solved by the Invention In the above-described conventional carbon thin film forming apparatus, the film forming rate is about 1/10 as slow as that of the general sputtering method, and the sputtering is active in the hydrogen gas atmosphere. As the reaction with hydrogen is promoted, hydrogen is excessively contained in the film, resulting in a soft film having a mohs hardness of 2-3. Further, since the reaction in the hydrogen plasma is repeated, there is a problem that complicated generated species are taken into the film and an unstable and inhomogeneous thin film is formed.

Therefore, the present invention is intended to solve the above problems and to provide an apparatus capable of improving the film formation rate, eliminating excess hydrogen content, and forming a uniform and dense carbon thin film.

E. Means for Solving the Problems In the apparatus for forming a carbon thin film of the present invention, the first section in the vacuum chamber partitioned by the plate-like electrode is set to an inert gas atmosphere, and is placed between the graphite target and the counter electrode. A high-frequency voltage is applied to generate an inert gas plasma to relatively coarsely evaporate graphite and to scatter primary particles having large particles. Then, this primary generated species is introduced into the second section in the hydrogen gas atmosphere. Here, a high-frequency voltage is applied between the plate electrode and the substrate holder to generate hydrogen plasma, and the primary generated species are exposed to the plasma to react with H ₂ to form a carbon thin film on the substrate. At this time, since the inert gas has a larger mass than the hydrogen gas, a large amount of primary generated species with large particles are generated. Further, when exposed to hydrogen plasma, the primary generated species are decomposed and activated to form a dense and strong thin film at a high speed. Hydrogen contained in the film is reduced by the two-step sputtering as described above.

C. Examples Examples of the present invention are shown in FIGS. FIG. 1 is a schematic vertical sectional front view of an apparatus for forming a carbon thin film, FIG. 2 is a plan view of a plate electrode, and FIG. 3 is a graph showing an infrared absorption spectrum of the formed carbon thin film. It should be noted that the same components as those of the conventional device shown in FIG. 4 in FIG. In FIG. 1, the vacuum chamber 1 is partitioned into first and second compartments A and B by a plate-shaped electrode 16 provided above the counter electrode 11. The plate-shaped electrode 16 is provided with a hole 16a that allows the first and second sections A and B to communicate with each other, and is connected to a high-frequency power source 18 via an external matching box 17. This plate-shaped electrode 16 has an insulating member 19 inside the container 2.
Is attached through. The gas introduction port 3 of the first section A communicates with an external Ar gas tank 22. On the other hand, a gas inlet 20 is opened in the second section B and communicates with the hydrogen gas tank 14 via the mass flow controller 21 by an air supply pipe.

Next, the operation of the above embodiment will be described. First, evacuate the vacuum chamber 1 to adjust the mass flow controllers 15 and 21,
r gas is introduced into the first compartment A side, and hydrogen gas is introduced into the second compartment B side. As a result, the inside of the vacuum chamber 1 becomes a pseudo two-phase system having different atmospheres. After reaching the predetermined pressure in each compartment A, B, the target holder electrode 5 and the counter electrode
A high frequency voltage is applied between 11 and 11 to decompose and scatter the graphite target 6. The decomposed graphite target particles are relatively large because the mass of Ar gas is larger than that of hydrogen gas. The large size of the particles contributes to high-speed film formation.

Next, a high frequency voltage is applied between the plate electrode 16 and the substrate holder 12 to generate hydrogen plasma. Then, the scattered graphite particles pass through the flow holes 16a of the plate electrode 16 and enter the second section B, where they are exposed to hydrogen plasma. Then, it is decomposed by hydrogen plasma, reacts with H ₂ , is activated, and adheres to the substrate 13 densely and firmly. Thus, a uniform and hard (mohs hardness 6-8) thin film is formed.

Due to the presence of the counter electrode 11, the first section A to the second section B
Helps the diffusion of graphite particles into the. That is, when a high frequency voltage is applied between the plate electrode 5 and the counter electrode 11, the first
Main plasma in the area between the graphite target 6 and the counter electrode 11 in the section A (brightly emitting area)
Occurs, Ar plasma and H ₂ plasma are continuously generated around the lead of the counter electrode 11 and around the second partition electrode 11, and flow (diffusion) occurs due to the difference in the concentration balance of the generated particles. Graphite particles generated in the graphite target / counter electrode 11 are generated in the plasma by the counter electrode 11
On the substrate 13 as a diamond-like (transparent) carbon film by diffusing along the lead of, and being decomposed and reacted in the plasma rich in H ₂ gas. Therefore, since the reaction occurs while diffusing in the plasma, a dense film can be obtained.

The infrared absorption spectrum of the carbon thin film formed as described above is compared with that of the carbon thin film formed by the conventional apparatus shown in FIG. 4, as shown in FIG. From this result, it is clear that the excess hydrogen contained in the formed carbon thin film was reduced.

H. Effect of the Invention As described above, the present invention provides a magnetron type target holder and a counter electrode that hold a target in a vacuum chamber facing each other, and a substrate holder that holds a substrate above the counter electrode. In an apparatus for applying a high-frequency voltage between a target holder and a counter electrode in a hydrogen gas atmosphere to form a carbon thin film on a substrate arranged on a substrate holder, the vacuum chamber is partitioned by a plate electrode having a flow hole, A section and a second section are provided, the target holder and the counter electrode are arranged in the first section, and an inert gas can be introduced, and the substrate holder is arranged in the second section, and the substrate holder and the plate-like member are arranged. Since a high frequency voltage can be applied between the electrodes and hydrogen gas can be introduced into the second compartment, the following effects can be obtained.

(1) A surplus hydrogen content is small and a highly humid and uniform carbon thin film can be formed in a short time.

(2) Since the local plasma activity (non-equilibrium) is increased, a denser and more stable film can be formed.

(3) The film thickness distribution is appropriately suppressed.

(4) Since the structure of the device is simple, it is easy to use and easy for maintenance and inspection.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional front view of a carbon thin film forming apparatus of the present invention, FIG. 2 is a plan view of a plate-like electrode, FIG. 3 is a graph showing an infrared absorption spectrum of the formed carbon thin film, and FIG. The figure is a schematic vertical sectional front view of a conventional apparatus. 1 ... vacuum chamber, 2 ... gas inlet, 5 ... plate electrode, 6
...... Graphite target, 11 …… Counter electrode, 12 ……
Substrate holder, 13 ... Substrate, 14 ... Hydrogen gas tank, 15 ...
… Mass flow controller, 16 …… Plate electrode, 20 …… Gas inlet, 21 …… Mass flow controller, 22 …… Inert gas (Ar gas) tank, A …… First compartment, B …… Second
Parcel.

Claims (1)

(57) [Claims] 1. A magnetron type target holder for holding a target and a counter electrode facing each other in a vacuum chamber, a substrate holder for holding a substrate above the counter electrode, and a target holder in an H ₂ gas atmosphere. In a device for forming a carbon thin film on a substrate placed on a substrate holder by applying a high frequency voltage between opposing electrodes, the vacuum chamber is partitioned by a plate electrode having a flow hole to provide a first section and a second section. , The target holder and the counter electrode are arranged in the first compartment and an inert gas can be introduced, the substrate holder is arranged in the second compartment, and a high frequency voltage is applied between the substrate holder and the plate electrode. And a H ₂ gas can be introduced into the second compartment while applying a carbon thin film.