JP3617056B2 - Ion plating equipment - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an ion plating apparatus, and more particularly to a plasma gun counter electrode used in an ion plating apparatus for forming an insulating film.
[0002]
[Prior art]
Ion plating is a film forming method in which evaporated atoms and / or reactive atoms heated and evaporated are ionized and collide with a negatively applied substrate to be solidified. A conventional ion plating apparatus for performing such ion plating generates, for example, as shown in FIG. 3, a vacuum chamber 1 having a crucible 5 therein, an electron gun 3 for irradiating the crucible with an electron beam 4, and a plasma 15. A plasma gun 14, a counter electrode 16 for attracting electrons in the plasma, a reaction gas introduction nozzle 13 for introducing a reaction gas 21, and the like are provided. The substrate 8 is applied negatively, and the electron beam 4 is irradiated to the crucible 5 by the electron gun 3. Then, the film material 6 in the crucible is dissolved and evaporated to form an evaporation flow 7 of the film material 6, a plasma 15 is generated by the plasma gun 14, electrons are attracted by the counter electrode 16, and the evaporation flow 7 and the reaction gas 21 are generated. The insulating film was formed on the substrate by positively ionizing and colliding the ionized vaporized flow 7 and the reaction gas 21 against the negatively applied substrate 8 to be solidified.
[0003]
[Problems to be solved by the invention]
However, in such a conventional ion plating apparatus, the insulating film formed on the substrate is also formed on the surface of the counter electrode 16 in addition to the substrate, whereby the conductivity of the counter electrode 16 decreases as the film formation proceeds. There was a problem to do. For this reason, there is a problem that the plasma 15 is unstable or cannot be maintained, and the evaporation flow and the ionization of the reaction gas due to the plasma are extremely reduced. As a result, the ion plating is not substantially performed and it is merely vapor deposition, and the film quality of the insulating film formed on the substrate is deteriorated (becomes porous rather than dense, crystallization becomes insufficient, hardness decreases, Etc.) and the adhesion between the insulating film and the substrate is reduced. Furthermore, since such a phenomenon occurs in a very short time, for example, several minutes to several tens of minutes, there is a problem that a stable operation of the plasma gun is practically impossible.
[0004]
The present invention has been made to solve the various problems described above. That is, according to the present invention, it is difficult to form an insulating film on the surface of the counter electrode, the electrons in the plasma can be attracted stably for a long time, and a high-quality insulating film can be stably formed on the substrate for a long time. An object of the present invention is to provide an ion plating apparatus capable of forming a film.
[0005]
[Means for Solving the Problems]
According to the present invention, a vacuum chamber in which the inside is evacuated and maintained at a vacuum pressure suitable for ion plating, and a reaction gas is introduced into the interior, and an electron beam is irradiated into the crucible in the vacuum chamber. Then, the evaporation material is dissolved and evaporated, and an electron gun that forms an evaporation flow toward the substrate by the evaporated evaporation material, a plasma gun that generates a plasma that intersects the evaporation flow almost at right angles, and substantially opposite to the plasma gun A counter electrode that attracts electrons in the plasma and passes through the plasma to positively ionize the reaction gas and an electrode surface of the counter electrode that is higher than the pressure of the vacuum degree by 10 ⁻³ torr or more. comprising a said electrode surface such that the pressure and the gas membrane device covering with an inert gas, the gas film device, the counter electrode with an inert gas is provided on the electrode surface of the counter electrode It comprises a plurality of gas blowing holes that are blown into the electrode surface in a shower form, and a gas supply device that supplies an inert gas to the gas blowing holes through the inside of the counter electrode. There is provided an ion plating apparatus characterized in that an insulating film is formed on the substrate by colliding and solidifying the substrate applied to the substrate.
[0007]
[Action]
In the present invention, the average moving distance (mean free path) of atoms or molecules until the vapor or reactive gas atoms or molecules collide with each other in the vacuum chamber is determined by the pressure in the normal ion plating apparatus (for example, 5 × At 10 ⁻⁴ torr, it is long (for example, 500 mm), and at pressures of 10 ⁻³ torr or more, it is short (for example, 50 mm or less).
[0008]
That is, according to the configuration of the present invention, the electrode surface of the counter electrode is covered with an inert gas so that the pressure on the electrode surface of the counter electrode is 10 ⁻³ torr or higher, which is higher than the pressure in the vacuum chamber. Therefore, the vapor or reactive gas atoms or molecules passing through a pressure close to a vacuum (for example, 5 × 10 ⁻⁴ torr) and approaching the counter electrode immediately become inert gas atoms in the inert gas. Collides with (molecule) and bounces back. Therefore, the evaporation flow and the atoms or molecules of the reactive gas that form the insulating film hardly reach the surface of the counter electrode, and the insulating film is hardly formed on the surface of the counter electrode. Thereby, the conductivity of the counter electrode can be maintained for a long time, the plasma by the plasma gun is stable for a long time, the evaporation flow by the plasma and the ionization of the reaction gas are also stably performed, and the crystallization is dense. A high-quality insulating film that is sufficient, has high hardness, and high adhesion to the substrate can be formed over the substrate for a long time.
[0009]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an overall configuration diagram of an ion plating apparatus according to the present invention, and FIG. 2 is another overall configuration diagram of an ion plating apparatus according to the present invention. In FIG. 1 to FIG. 3, common parts are used with the same reference numerals.
[0010]
1 and 2, an ion plating apparatus according to the present invention dissolves and evaporates a film material 6 in a vacuum chamber 1 to form an evaporating flow 7 toward a substrate 8. A reactive gas 21 is introduced into the vacuum chamber 1. Then, a plasma 15 intersecting with the evaporation flow 7 is generated by the plasma gun 14, and electrons in the plasma 15 are attracted by the counter electrode 16 to positively ionize and ionize the evaporation flow 7 and the reaction gas 21. An insulating film is formed on the substrate 8 by colliding and solidifying the vaporized flow 7 and the reaction gas 21 against the substrate 8 to which negative is applied.
[0011]
That is, in FIGS. 1 and 2, the vacuum chamber 1 is evacuated 2 by a vacuum pump (not shown), and the inside of the chamber is maintained at a pressure suitable for ion plating, for example, 5 × 10 ⁻⁴ torr.
The ion plating apparatus according to the present invention includes an electron gun 3, which generates an electron beam 4 and irradiates the crucible 5 to dissolve and evaporate the evaporation material 6. An evaporation flow 7 is formed.
[0012]
Furthermore, the ion plating apparatus according to the present invention includes a plasma gun 14, a focusing coil 17, a counter electrode 16, a focusing coil 18, an insulating portion 19, and a counter electrode power supply 20 as means for ionizing the vaporized flow 7 and the reaction gas 21. I have.
The plasma gun 14 generates a plasma 15 in which positive ions and electrons coexist. The counter electrode 16 is installed at a position substantially opposite to the plasma gun 14, and is insulated from the vacuum chamber 1 through the insulating portion 19. The counter electrode 16 is applied with a relatively positive (plus) voltage from the vacuum chamber 1 by the counter electrode power source 20, attracts electrons in the plasma 15 to the counter electrode 16, and passes through the plasma. The reaction gas 21 is ionized into positive ions.
[0013]
The focusing coils 17 and 18 generate a magnetic field for converging the plasma so that the plasma does not spread. The converging coils 17 and 18 are preferably provided on both the plasma gun side and the counter electrode side as shown. The converging coil 18 on the counter electrode side may be provided inside the counter electrode (not shown).
When the plasma 15 emitted from the plasma gun 14 is irradiated onto the evaporation flow 7 with the above-described configuration, when the electrons of the plasma 15 mainly collide with the evaporation flow 7 and the reaction gas 21, the evaporation flow 7 and the reaction gas 21 are positive ions. To ionize.
[0014]
A high frequency (for example, 13.56 MHz) is applied to the substrate 8 via a high frequency matching device 10 from a high frequency power supply 11. The substrate 8 itself may be an insulator or a conductor, but since the insulator is formed on the substrate 8, a high frequency is applied so that a negative voltage can be applied to the surface of the insulator. The high-frequency matching device 10 is a matching device that matches the impedance on the load side so that a negative voltage can be effectively applied to the surface of the insulator. Note that a heater 12 is preferably provided in order to maintain the substrate 8 at a constant temperature and to stabilize the film forming conditions.
[0015]
A reaction gas 21 is introduced into the vacuum chamber 1 through a reaction gas introduction nozzle 13. The reactive gas 21 is oxygen (O ₂ ) when, for example, alumina Al ₂ O ₃ is formed on the substrate 8. The evaporation material 6 is aluminum (Al) or alumina (Al ₂ O ₃ ), and oxygen O ₂ is introduced as the reaction gas 21 to form alumina (Al ₂ O ₃ ) on the substrate. Note that the ratio of aluminum and oxygen of alumina formed on the substrate is not necessarily 2: 3, and strictly speaking, it should be expressed as Al _x O _y , but here it is simply expressed as Al ₂ O ₃ .
[0016]
The ion plating apparatus of the present invention further includes a gas film apparatus 30 that covers the electrode surface of the counter electrode 16 with an inert gas 22 of 10 ⁻³ torr or more.
In FIG. 1, a gas membrane device 30 includes a plurality of gas blowing holes 23 provided on the electrode surface of the counter electrode 16, and a gas supply device that supplies an inert gas to the gas blowing holes 23 through the inside of the counter electrode 16, that is, a gas supply device. And an active gas introduction nozzle 24. Thus, the inert gas 22 can be blown out from the front surface of the counter electrode 16 to the electrode surface through the gas blowing hole 23 from the inside of the counter electrode.
[0017]
In FIG. 2, the gas film device 30 includes a gas nozzle 25 provided so as to flow an inert gas along the electrode surface of the counter electrode 16, and a gas supply device that supplies the inert gas 22 to the gas nozzle 25, that is, a gas supply device. And an active gas introduction nozzle 24. Thereby, the inert gas 22 can be sprayed along the electrode surface of the counter electrode 16.
[0018]
The pressure of the inert gas 22 is preferably 10 ⁻³ torr or more, and particularly preferably 10 ⁻² torr or more. The movement distance of the gas molecules until the gas molecules collide with each other in the vacuum chamber is about 500 mm at a pressure in a normal ion plating apparatus, that is, about 5 × 10 ⁻⁴ torr, and about 50 mm at 10 ⁻³ torr. It is about 5 mm at 10 ⁻² torr and about 0.5 mm at 10 ⁻¹ torr. Therefore, by making the pressure of the inert gas 22 in the gas film device 30 at least 10 ⁻³ torr or more, the gas molecules that are close to the counter electrode collide with the gas molecules of the high-pressure inert gas and bounce off. Can do.
[0019]
The inert gas 22 is a gas such as helium (He), neon (Ne), or argon (Ar), and an argon gas having a large molecular weight and a low price is particularly preferable. As a result, the gas molecules approaching the counter electrode can be reliably rebounded by the collision with the gas molecules of the inert gas having a large molecular weight.
Note that the reactive gas 21 may be used directly instead of the inert gas 22, but the effect is weaker than that of the inert gas.
[0020]
Using the apparatus shown in FIG. 1, an ion plating test was performed using Al ₂ O ₃ (aluminum oxide) as the evaporation material 6 and oxygen (O ₂ ) as the reaction gas 21. At the time of only the first vacuum evacuation, the gas is evacuated to the order of 10 ⁻⁶ torr, then the evaporation material 6 is evaporated by the electron gun 3, oxygen (O ₂ ) is introduced from the reaction gas introduction nozzle 13, and 5 × 10 ^{− The} film was formed under a pressure of ⁴ torr. The output of the plasma gun 14 was 60 V × 150 A, and the counter electrode power source 20 was several V (volts). The electron gun 3 was about 6 kW, and the voltage applied to the substrate 8 was −100 to −200V. Further, the substrate 8 was heated to 500 ° C. by the heater 12.
[0021]
As a result of the above test, the plasma from the plasma gun can be stably maintained for a long time (2 hours or more), the ionization of the evaporation flow 7 and the reaction gas 21 can be maintained for a long time, the film quality is good, and the adhesion with the substrate 8 is also good. An alumina insulating film could be formed. In addition, the counter electrode is easily exposed to plasma and thus easily reaches a high temperature. However, as a result of the above test, an accompanying effect that cooling is performed together with blowing / blowing of an inert gas was obtained. Furthermore, even if the ion plating apparatus according to the present invention is used without applying a negative voltage to the substrate, the ionized evaporation flow and the reaction gas are formed on the substrate, so that there is no simple means of “evaporation” without means for ionization. Compared with, very good film quality was obtained.
[0022]
【The invention's effect】
As described above, in the present invention, the moving distance of gas molecules until gas molecules collide with each other in a vacuum chamber is long (for example, 500 mm) at a pressure (for example, 5 × 10 ⁻⁴ torr) in a normal ion plating apparatus. This is based on a novel approach that utilizes the fact that it is short (for example, 50 mm) at a pressure of 10 ⁻³ torr or more .
[0023]
That is, according to the present invention, since the electrode surface of the counter electrode is covered with an inert gas of 10 ⁻³ torr or more by the gas film device, it passes through a pressure close to vacuum (for example, 5 × 10 ⁻⁴ torr). The vapor or reactive gas atoms or molecules approaching the counter electrode immediately collide with the gas atoms (molecules) of the inert gas and bounce off in the inert gas. Therefore, the evaporation flow and the atoms or molecules of the reactive gas that form the insulating film hardly reach the surface of the counter electrode, and the insulating film is hardly formed on the surface of the counter electrode. Thereby, the conductivity of the counter electrode can be maintained for a long time, the plasma by the plasma gun is stable for a long time, the evaporation flow by the plasma and the ionization of the reaction gas are also stably performed, and the crystallization is dense and A high-quality insulating film that is sufficient, has high hardness, and high adhesion to the substrate can be formed over the substrate for a long time.
[0024]
Therefore, in summary, according to the present invention, it is difficult to form an insulating film on the surface of the counter electrode, the electrons in the plasma can be attracted stably for a long time, and a high-quality insulating film can be stably formed for a long time. A film can be formed thereon.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an ion plating apparatus according to the present invention.
FIG. 2 is another partial configuration diagram of the ion plating apparatus according to the present invention.
FIG. 3 is an overall configuration diagram of a conventional ion plating apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Vacuum exhaust 3 Electron gun 4 Electron beam 5 Crucible 6 Evaporating material 7 Evaporating flow 8 Substrate 9 Insulating part 10 High-frequency matching device 11 High-frequency power source 12 Substrate heater 13 Reactive gas introduction nozzle 14 Plasma gun 15 Plasma 16 Counter electrode 17 Converging coil 18 Converging coil 19 Insulating part 20 Counter electrode power source 21 Reactive gas 22 Inert gas 23 Blowout hole 24 Inert gas introducing nozzle 25 Gas nozzle

Claims (1)

A vacuum chamber in which the inside is evacuated and maintained at a vacuum level suitable for ion plating, and a reaction gas is introduced into the interior;
An electron gun that irradiates an electron beam into the crucible in the vacuum chamber to dissolve and evaporate the evaporation material, and forms an evaporation flow toward the substrate by the evaporated evaporation material;
A plasma gun that generates a plasma that intersects the evaporative flow substantially perpendicularly;
A counter electrode that is installed at a position substantially opposite to the plasma gun and positively ionizes the evaporating flow and reaction gas that have passed through the plasma by attracting electrons in the plasma;
A gas film device that covers the electrode surface with an inert gas so that the electrode surface of the counter electrode has a pressure of 10 ⁻³ torr or higher, which is higher than the pressure of the vacuum degree,
The gas membrane device includes a plurality of gas blowing holes provided on the electrode surface of the counter electrode for blowing an inert gas to the electrode surface of the counter electrode in a shower shape, and an inert gas in the gas blowing hole through the inside of the counter electrode. A gas supply device for supplying
An ion plating apparatus characterized in that an insulating film is formed on a substrate by colliding and solidifying the ionized evaporative flow and reaction gas against the substrate to which negative is applied.

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