JP2905421B2 - Reactive 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 a reactive gas such as a magnetron sputter or a high-frequency sputter which forms a film of a reactive compound on a processing material by reacting a reaction gas supplied into a chamber with particles struck out of a target. It relates to a sputtering device.

[0002]

2. Description of the Related Art
Various types of reactive sputtering apparatuses have been proposed as reactive sputtering apparatuses that form a film on a substrate by reacting a reaction gas supplied into a chamber with particles struck out of a target. Japanese Patent Laid-Open Publication No. Sho 62-56570 discloses a technique for improving the sputtering efficiency. That is, the discharge gas introduction pipe is arranged near the surface of the target, and the reaction gas introduction pipe is arranged near the surface of the substrate to reduce the concentration of the reaction gas near the surface of the target and suppress the generation of the reaction compound on the surface of the target. By increasing the concentration of the reaction gas near the substrate surface, the film formation reaction can be performed efficiently.

However, the pressure in the chamber during sputtering is about 0.01 to 100 mTorr, and the reaction gas and the discharge gas have molecular flow or intermediate flow characteristics under the above pressure. Even if the discharge gas and the discharge gas are introduced separately, the reaction gas and the discharge gas will interdiffuse, and the atmosphere cannot be isolated in each of the introduction regions. Could not be improved.

Further, in order to isolate the atmosphere between the reaction gas and the discharge gas, a differential pressure plate forming an orifice is provided between the target and the substrate, and the reaction gas and the reaction gas are provided in respective chambers separated by the differential pressure plate. A reactive sputtering apparatus for separating and introducing a gas is disclosed in JP-A-6-41733.

In the reactive sputtering apparatus having the above structure, mutual diffusion of the reaction gas and the discharge gas can be prevented by the differential pressure plate, but abnormal electric discharge occurs frequently due to electric field concentration generated at the opening edge of the differential pressure plate. There is a problem that the sputtering efficiency is reduced.

[0006] Further, there is a problem that the evacuation efficiency is deteriorated with the installation of the differential pressure plate, and in particular, the volume of both chambers separated by the differential pressure plate is large and the evacuation time is long, resulting in poor productivity.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is intended to prevent the mutual diffusion of a reactant gas and a discharge gas to improve the sputtering efficiency, form a good quality film, and improve the vacuum evacuation efficiency. It is an object of the present invention to provide a reactive sputtering apparatus having good productivity and high productivity.

[0008]

In order to achieve the above object, the present invention provides a reactive sputtering apparatus for forming a film on a processing material by reactive sputtering. A cathode chamber in which the target is located with a cross-sectional area smaller than the cross-sectional area. The main chamber is provided with a reaction gas supply unit opened near the substrate and connected to a vacuum exhaust device. The chamber has a discharge gas supply section that opens near the target, a detachable plate near the side wall is detachably provided, and the cathode chamber is attached to the main chamber so that the opening of the main chamber can be opened and closed. And

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2 show a reactive sputtering apparatus 1 according to the present invention. The chamber 2 of the reactive sputtering apparatus 1 is composed of a main chamber 3 in which the substrate 11 is located and a plurality of cathode chambers 4 in which targets 23 are located.

The main chamber 3 comprises a flat rectangular body 3a having a side wall 13 and a lid 9 which can be opened and closed by a hinge 10 at one end of the side wall 13. In the main body 3a, a substrate holder 8 made of a disk is attached to a rotating shaft 7 which is rotated by a driving device (not shown). Installed. An opening 6 is provided at the center of the main body 3a, and is connected to a vacuum exhaust device (not shown). Further, a reaction gas supply pipe 14 that opens above the cathode chamber 4 and near the substrate 11 is provided on the side wall 13 of the main body 3a.

On the other hand, a plurality of (four in the figure) positions of the lid 9 opposed to the rotation locus of the substrate 11 of the substrate holder 8 are shown.
Opening 12 is provided.

The cathode chamber 4 is provided with the opening 12
And a bottomed cylindrical body having an opening 4a in the same manner as that described above. An inner wall near the opening 4a is removably attached with a deposition-preventing plate 17, and has a plurality of permanent magnets 18 at the bottom and a negative DC current 19 Is connected to the electrode 20. The target 2 is placed on the electrode 20.
The discharge gas supply pipe 2 is opened in the vicinity of the target 23 in the cathode chamber 4.
2 are provided. Note that a pulsed heavy DC power supply may be applied to the electrode 20. The cathode chamber 4 is attached to the main chamber 3 by a hinge 16 so that the opening 12 of the lid 9 can be opened and closed.

Here, the conductance (flow resistance) in the chamber 2 will be described. If there is a portion where the cross-sectional area changes abruptly, the value of the conductance C (m ³ / sec) becomes smaller (the flow resistance becomes larger) due to the gas flow resistance due to diffusion contraction caused by the difference in cross-sectional area.
In the chamber 2, the opening 12 corresponds thereto, and the conductance C of the chamber 2 has a small value.

For example, the sectional area S1 of the main chamber 3
Is set to about twice the cross-sectional area S2 (opening 12) of the cathode chamber 4, the conductance C becomes about １ ／ times that of the integrated chamber having the cross-sectional area of only S1, and the reaction supplied to the main chamber 3 Interdiffusion between the gas and the discharge gas supplied to the cathode chamber 4 is prevented,
Each atmosphere is almost completely isolated.

[0015] More specifically, the cross-sectional area S1 of the main chamber 3, 360cm ² ~10,000cm ² mm, the cross-sectional area S2 of the cathode chamber 4, 180cm ² to 500
cm ² is set.

Next, a case where an alumina film is formed on the substrate 11 by the reactive sputtering apparatus 1 will be described. First, the lid 9 of the main chamber 3 is opened downward with the hinge 10 as a fulcrum, and the substrate holder 8 is removed from the rotating shaft 7 of the main chamber 3. After mounting the plurality of substrates 11 on the substrate holder 8, the substrate holder 8 is mounted on the rotating shaft 7, and the target 2 made of aluminum is formed on the cathode electrode 20 of each cathode chamber 4.
3 is placed, and the lid 9 is closed. The substrate 11
The distance between the target and the target 23 is set to 150 to 250 mm.

Next, the main chamber 3 and the cathode chamber 4 are evacuated to 10 mTorr by a vacuum exhaust device (not shown).
After evacuating to a degree, O ₂ (reaction gas) is supplied to the main chamber 3 from the reaction gas supply pipe 14, and Ar (discharge gas) is supplied to the cathode chamber 4 from the discharge gas supply pipe 22.

Thereafter, a voltage of 300 to 500 W is applied to the electrode 20, and the rotating shaft 7 is driven to rotate the substrate holder 8 at a predetermined speed. As a result, when the substrate 11 moves to the position 15 facing the opening 12, the substrate 11 is hit from the target 23, and an alumina film is formed by particles reacted with the reaction gas.

At this time, as described above, since the conductance C of the cathode chamber 4 is small, the reaction gas supplied to the main chamber 3 does not diffuse into the cathode chamber 4. Accordingly, a film of alumina as a reaction compound is not formed on the surface of the target 23, and the sputtering of the target 23 is performed stably.
Similarly, the discharge gas supplied to the cathode chamber 4 does not diffuse into the main chamber 3. Further, since the reaction gas is supplied near the surface of the substrate 11,
Since the discharge gas sucked from the cathode chamber 4 into the main chamber 3 by the vacuum exhaust device does not pass around the substrate 11 and the reaction gas concentration near the surface of the substrate 11 is kept high, The reaction efficiency is very good.

Finally, when the formation of the film is completed, the electrode 20
The supply of the voltage applied to the substrate holder is stopped, and the rotation of the substrate holder 8 and the supply of the discharge gas and the reaction gas are stopped. Then, after the pressure of the chamber 2 is restored by appropriate means, the main chamber 3
The lid 9 is opened to remove the substrate holder 8, and the substrate 11 is removed from the substrate holder 8 to complete the operation. Since a plurality of the substrates 11 are simultaneously processed, additional time other than the actual film formation time per one substrate (time required for evacuation of the chamber 2, pressure recovery, pressure stabilization, and the like) is reduced. Further, a film having a uniform thickness and composition is formed on the substrate 11.

The attachment plate 17 prevents the reactant from adhering to the inner wall of the cathode chamber 4. The attachment plate 17 can be removed from the cathode chamber 4, so that the cathode chamber 4 is hinged. The maintenance can be easily performed by opening the lid 9 from the lid 16.

Further, when forming a Si ₃ N ₄ film on the substrate 11, Si is used for the target 23 and N ₂ gas is used for the reaction gas. The distance between the target 23 and the substrate 11 is set to about 60 mm, a direct current of 3500 W is applied to the electrode 20, and the main chamber 3 and the cathode chamber 4 are evacuated to about 10 mTorr. Under the above-mentioned conditions, the film formation speed was 4000 ° / min, which was significantly improved as compared with the conventional general film formation speed. Under the above conditions, a 1500 ° thick Si ₃
When the N ₄ film was produced, the substrate temperature could be kept at 80 ° C. or less.

The above reactive sputtering apparatus 1
As shown in FIG. 3, a high-frequency power supply 26 may be connected to the rotating shaft 7 via an impedance matching circuit 25, or an induction coil may be provided near the substrate 11 at the processing position 15 as shown in FIG. 28, and a high frequency power supply 26 may be connected to the induction coil 28 via an impedance matching circuit 25. In the configuration shown in FIGS. 3 and 4, the reaction gas is activated by the plasma generated around the substrate 11, so that the reaction efficiency is further improved, and the adhesion force is weak in the film formed on the substrate 11. Since atoms and impurities are knocked out by the plasma, the film is formed only of atoms having strong adhesion. Since a capacitor is built in the impedance matching circuit 25, a DC bias can be obtained even when the substrate 11 is made of a conductive material.

For example, when an SiO ₂ film is formed on the substrate 11 by the reactive sputtering apparatus 1 shown in FIGS. 1 and ₂ , Si is used for the target 23 and the reaction gas (O ₂ ) and the discharge gas (Ar) are mixed. The flow rate ratio was 0.3: 1.0, and the electrode 2
A direct current of 2000 W is applied to 0, and the main chamber 3 and the cathode chamber 4 are evacuated to about 10 mTorr. The refractive index of the film formed under these conditions was 1.9. However, using the reactive sputtering apparatus 1 having the configuration shown in FIGS.
When the voltage was set to 200 W and the film was formed in a state where plasma was generated around the substrate 11, the refractive index of the film was 1.5, and the transparency of the film could be improved. Thereby, it can be understood that the impurities are beaten out of the substrate 11.

The reactive sputtering apparatus for processing a plurality of substrates 11 may have the configuration shown in FIG. The reactive sputtering apparatus 30 is configured such that a plurality of cathode chambers 32 are detachably attached to an outer periphery of a main chamber 31 formed of a cylindrical body by hinges 33. The inside of the main chamber 31 is connected to a motor (not shown). A substrate holder 34 composed of a hollow octagonal prism provided rotatably in the direction of the arrow is disposed.

FIG. 1 shows other components and operation procedures.
The same parts as in the reactive sputtering apparatus 1 shown in FIG. Needless to say, even in this reactive sputtering apparatus 30,
The cross-sectional area of each cathode chamber 32 is provided to be smaller than the cross-sectional area of the main chamber 31. Since the gas does not diffuse into the main chamber 31, a good quality film is efficiently formed on the substrate 11.

In the above description, the substrate holder 8 that is driven to rotate
A plurality of cathode chambers 4 (32) are arranged while a plurality of substrates 11 are attached to the substrate. However, the substrate holder 8 is fixed, and the cathode chamber 4 may be provided to face the substrate 11. The number of the substrate 11 and the number of the cathode chambers 4 may be one each.

As shown in FIGS. 6 and 7, the reactive sputtering apparatus can be used by being incorporated in a continuous sputtering apparatus 40. The above continuous sputtering apparatus 40
In this case, a film is formed on the substrate 11 that has been transferred in the direction of the arrow by the substrate holder 8 through a pretreatment or the like. In this case, as in the case of the sputtering apparatus 1, the main chamber 41 also serving as a transfer path is cut off. The cross-sectional area S4 of the cathode chamber 42 is provided to be smaller than the area S3. In addition, about the structure and operation | movement of the reactive sputtering apparatus 40, the same code | symbol is attached | subjected to the same part as the reactive sputtering apparatus 1, and description is abbreviate | omitted.

[0029]

As is apparent from the above description, in the reactive sputtering apparatus according to the first aspect, the cathode chamber is attached to the opening formed in the main chamber, that is, in the communicating portion between the two chambers. The cross-sectional area has a shape that changes rapidly, and the conductance of the chamber can be reduced. This allows
The reaction gas supplied to the main chamber is prevented from diffusing into the cathode chamber, and the discharge gas supplied to the cathode chamber is prevented from diffusing into the main chamber (interdiffusion). To be isolated. Therefore, since the surface of the target and the reactive gas do not react with each other to generate a compound, the sputtering efficiency can be improved, and a high-quality film is formed as a processing material.

Further, since the reactive sputtering apparatus is not provided with a differential pressure plate, abnormal discharge does not occur, a film can be stably formed on the substrate, and the volume of the cathode chamber is smaller than that of the main chamber. Therefore, the evacuation efficiency of the entire chamber is good.

Further, since the cathode chamber can be cleaned or replaced with the main chamber removed from the main chamber, and the deposition-preventing plate can be removed or replaced from the cathode chamber, maintenance can be easily performed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a reactive sputtering apparatus according to the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a partial cross-sectional view of a reactive sputtering apparatus in which a high-frequency power source is connected to a shaft.

FIG. 4 is a partial sectional view of a reactive sputtering apparatus provided with an induction coil.

FIG. 5 is a sectional view of a reactive sputtering apparatus according to another embodiment.

FIG. 6 is a sectional view of a continuous sputtering apparatus incorporating the reactive sputtering apparatus according to the present invention.

FIG. 7 is a sectional view taken along the line III-III of FIG. 6;

[Explanation of symbols]

1, 30: reactive sputtering apparatus, 2: chamber, 3, 31, 41: main chamber, 4, 32, 4
2 ... Cathode chamber, 11 ... Substrate, 14, 22 ... Supply pipe, 17 ... Prevention plate, 20 ... Electrode, 40 ... Continuous sputtering device.

Claims (1)

(57) [Claims] 1. A reactive sputtering apparatus for forming a film on a processing material by reactive sputtering, comprising: a main chamber in which a substrate is located; and a cathode in which a target has a sectional area smaller than that of the main chamber. The main chamber is provided with a reaction gas supply unit opened near the substrate and connected to a vacuum exhaust device, while the cathode chamber is provided with a discharge gas supply unit opened near the target. A reactive sputtering apparatus characterized in that an attachment plate is detachably provided near a side wall, and a cathode chamber is attached to the main chamber so that an opening of the main chamber can be opened and closed.