JPH0732126B2 - ICB deposition equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ICB vapor deposition apparatus, and more particularly to improvement of an operation sequence when a vapor deposited thin film is formed.

[Conventional technology]

Fig. 1 shows the conventional ICB shown in Japanese Patent Publication No. 54-9592.
It is a sectional view of a (cluster ion beam) type thin film forming apparatus. In the figure, 1 is a crucible, 2 is a vapor deposition substance to be melted in the crucible 1, 3 is at least one nozzle opened in the upper part of the crucible 1, and the molten substance 2 is evaporated from the nozzle 3. Then, the vapor is ejected to form the cluster 4. 5 is a bombard filament for heating the crucible 1, 6 is an AC power source for heating the bombard filament 5 by energization, 7 is a first DC power source for bias,
Reference numeral 8 denotes an ionizing filament, which causes the ionizing electrons emitted therefrom to collide with a part of the cluster 4 to form positively charged cluster ions. Reference numeral 9 is a grid for accelerating the ionizing electrons emitted from the ionizing filament 8 to collide them with the clusters 4 ejected from the crucible 1, 10 is an AC power supply for heating the ionizing filament 8 by electric current, and 11 is for biasing. Second DC power supply, 12 and 13
Is a grid electrode and an acceleration electrode for controlling acceleration of the ionized cluster 4, 14 is a substrate on which a thin film 15 is formed, 16 is a third DC power supply for bias, and 17 is the crucible 1.
Heat shield plate, 18 is a vacuum chamber, 19 is a heat shield plate for the ionized filament 8, 20 is a power supply device in which the DC power sources 7, 11, 16 and AC power sources 6, 10 are stored, and 21 is a vacuum chamber.
An ionization vacuum gauge for measuring the degree of vacuum in 18, a film thickness sensor 22 for measuring the vapor deposition film thickness, a shutter 23 for blocking vapor deposition of a vapor deposition material on the substrate 14, 24, the power source 20, and a shutter 23
Is a control device for controlling the vacuum gauge 21 and the film thickness sensor 22, and 25 is an evacuation device.

First, the function of each bias power supply in the power supply device 20 is as follows. The first DC power supply 7 biases the potential of the crucible 1 positively with respect to the filament 5 so that the thermoelectrons emitted from the crucible heating filament 5 collide with the crucible 1. Next, the second DC power supply 11 biases the ionization filament 8 to a negative potential with respect to the grid 9, and draws out thermoelectrons emitted from the ionization filament 8 into the grid 9. Further, the third DC power supply 16 biases the grid electrode 12 to a positive potential with respect to the acceleration electrode 13 which is the ground potential, and the electric field lens formed between both electrodes causes positively charged cluster ions generated inside the grid to be generated. Control acceleration.

Next, the operation will be described.

The inside of the vacuum chamber 18 was 1.0 × 10 ^-6 Torr by the vacuum exhaust device 25.
After exhausting to a degree of vacuum, a signal is first transmitted from the control device 24 to the AC power supplies 6 and 10 for heating the filaments 5 and 8 in accordance with the vapor deposition operation sequence shown in FIG. Until the filament temperature reaches about 2000 ° C at the start-up speed, that is, the current
It is gradually heated until it reaches 25 to 30 A (Fig. 3, A,
B). After the completion of the energization heating process of the filaments 5 and 8, the controller 24 controls the first DC power source 7 and the second DC power source
A signal is transmitted to the DC power supply 11, and a bombardment voltage is applied by the first DC power supply 7 so that the bombarding current flowing between the crucible 1 and the filament 5 increases by about 0.5 A / min.
It is controlled until a predetermined bombardment input (product of bombarding current and bombarding voltage) is reached (Fig. 3C). At the same time, an ionization voltage is applied by the second DC power supply 11 so that the ionization current flowing between the grid 9 and the filament 8, which is a measure of the rate at which the cluster 4 is ionized, increases by about 0.5 A per minute, and a predetermined voltage is applied. It is controlled until the ionizing current is reached (Fig. 3D). After completing the startup of the ionization section and the bombard section, the control device
A signal is transmitted to the third DC power supply 16 by the 24, and a predetermined acceleration voltage is applied between the acceleration electrode 13 and the grid electrode 12 (FIG. 3E). After the start-up was completed, the degree of vacuum in the vacuum chamber 18 measured by the ionization vacuum gauge 21 was lowered to the extent that the performance of the thin film 15 formed on the surface of the substrate 14 was guaranteed, for example, 3.0 × 10 ⁻⁶ Torr or less. After that, a signal for opening the shutter 23 is transmitted from the control device 24 (FIG. 3F), vapor deposition is started on the surface of the substrate 14 and the thin film 15 is formed. The film thickness of the thin film 15 is measured by the film thickness sensor 22 to form a predetermined film thickness,
A signal for closing the shutter 23 is transmitted by the controller 24 to complete the deposition of the thin film 15 (FIG. 3G). Then the control device
24 from the acceleration voltage, bombardment voltage, and ionization voltage
A signal for turning off is transmitted to the third DC power supply 16, the first DC power supply 7, and the second DC power supply 11 (Fig. 3H), and then a signal for turning off the energization current of the filaments 5 and 8 is the AC power supply 6 and It is transmitted to 10 (FIG. 3I), and the shutdown is completed. After that, the apparatus is cooled while the vacuum exhaust apparatus 25 is operating, and then the substrate 14 is taken out.

[Problems to be solved by the invention]

Since the conventional ICB vapor deposition apparatus using the vapor deposition operation sequence is configured as described above, it has the following problems.

(1) The amount of degassing of the device varies depending on the past operation history, but since filament energization heating, bombarding, and ionization current startup are performed regardless of the degree of vacuum,
When the amount of degassing is large, it takes time to evacuate until the shutter is opened after the start-up is completed, and the vapor deposition substance remains in the device where the vapor deposition substance has already been ejected, which shortens the life of the device, The deposition material is wasted.

(2) After the completion of vapor deposition, the equipment is rapidly cooled by the rapid shutdown of the equipment, so that the vapor deposition material adheres to various parts of the equipment such as shields, and especially in the case of vapor deposition material that corrodes equipment materials. Not only does the life of the device decrease drastically, but thermal deformation due to rapid cooling sometimes causes destruction of parts of the device such as the filament.

(3) The electrons jumping out from the filament jump out toward the crucible and the grid, which are at ground potential, when no accelerating voltage is applied. In this case, however, the substrate is also at ground potential. May cause damage to the substrate.

The present invention has been made to solve the above problems, and obtains an ICB vapor deposition apparatus that operates in a vapor deposition operation sequence that can stably form a high-quality thin film and that can be used for a long life. The purpose is to

[Means for solving problems]

The ICB vapor deposition apparatus according to the present invention comprises a monitoring means for monitoring the degree of vacuum in a vacuum chamber, an acceleration voltage applying means for applying an acceleration voltage for accelerating the electric field of cluster ions, and an acceleration voltage by the acceleration voltage applying means in advance. Is applied to heat the bombarded filament and the ionized filament under a vacuum degree at which the performance of the thin film is ensured by obtaining the output of the monitoring means, and voltage is applied to the filament, and the voltage applied to the filament is gradually lowered. And the vapor deposition operation sequence control means for holding the filament in a heated state until the generation of vapor of the vapor deposition material is reduced after the voltage application is stopped, and then stopping the heating of the filament and cooling the filament. It is equipped with.

[Action]

In the present invention, an acceleration voltage for accelerating the electric field of cluster ions is applied in advance to prevent electrons from colliding with and damaging the substrate, and by raising the filament while monitoring the degree of vacuum, the thin film of Since the vapor of the vapor deposition material is ejected below the degree of vacuum that guarantees performance, a high quality thin film can be formed and the waste of vapor deposition material is reduced, and after the vapor deposition, the voltage applied to the filament is gradually lowered. Then, after the voltage application is stopped, the filament is kept in a heated state until the vapor of the vapor deposition substance is reduced, and then the filament heating is stopped to cool the filament. Adhesion of substances to the device can be reduced, and the life of the device can be extended.

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings. ICB
The vapor deposition apparatus is the same as that shown in FIG. 1 of the conventional example.

In this embodiment, a vacuum chamber is provided by the vacuum exhaust device 25.
After evacuation until the pressure in 18 reaches a vacuum degree of about 1.0 × 10 ^-6 Torr, according to the vapor deposition operation sequence shown in FIG.
Controls ICB deposition equipment.

The details will be described below with reference to the drawings. First of all the control device
From 24, a signal is transmitted to the third DC power supply 16 and a predetermined acceleration voltage is applied between the acceleration electrode 13 and the grid electrode 12 (FIG. 2A).

Next, the filament starting process is started.

A major feature of the present invention is a sequence in which the filament is activated under the application of an acceleration voltage.

A signal is transmitted from the control device 24 to the AC power supplies 6 and 10 for electrically heating the bombarded filament 5 and the ionized filament 8, and the current for heating the filament is gradually increased. At this time, the controller 24 constantly monitors the degree of vacuum in the vacuum chamber 18 measured by the ionization vacuum gauge 21, and the degree of vacuum is a value at which the performance of the thin film is guaranteed or about 1/3 of the value.
Do not send a signal to increase the energizing current of the filament until it becomes less than about (for example, 1.0 to 3.0 × 10 ^-6 Torr),
Wait until the degassed equipment has exhausted. In this way, while constantly checking that the degree of vacuum is equal to or lower than a predetermined value, the filament heating current is controlled to gradually increase the filament temperature to about 2000 ° C. (FIG. 2B). Next, a signal is transmitted from the controller 24 to the first DC power supply 7 and the second DC power supply 11, a bombardment voltage is applied between the crucible 1 and the bombarded filament 5 by the first DC power supply 7, and the crucible 1 is fed from the filament 5. Thermal electrons jump out toward the body and a bombard current flows. At the same time, an ionizing voltage is applied between the grid 9 and the ionizing filament 8 by the second DC power supply 11,
The thermoelectrons jump out toward the grid 9 and an ionization current flows. As with the filament energization heating process, the controller 24 uses the ionization vacuum gauge for the startup sequence of the bombarding current and the ionizing current to the predetermined values.
While constantly monitoring the degree of vacuum in the vacuum chamber 18 measured at 21, checking that the degree of vacuum is below a value that guarantees the performance of the thin film, set the startup speed until the above current reaches the set value. Control (FIG. 2C). When the start-up is completed in this way, the degree of vacuum has already reached the predetermined value, so the control device 24 can immediately transmit a signal to open the shutter 23 and start vapor deposition (second
(Figure D). When the film thickness measured by the film thickness sensor 22 reaches a predetermined value, a signal for closing the shutter 23 is transmitted from the control device 24, and vapor deposition of the thin film 15 is completed (FIG. 2E).

Next, the process of shutting down the device is started.

First, the controller 24 sends the first DC power supply 7 and the third DC power supply 11
Signal is transmitted, and the bombarding voltage and the ionization current are reduced and turned off so that the bombarding current and the ionization current decrease at a rate of about 0.1 to 0.5 A / min (FIG. 2F). By gradually reducing the bombardment voltage and the ionization voltage in this way, the vapor deposition material in the crucible is gradually cooled, and the above-mentioned generation from the crucible is gradually reduced. Next, signals are transmitted to the AC power supplies 6 and 10 to decrease the current value for heating the bombarded filament 5 and the ionized filament 8 by heating at a rate of about 2 A per minute.
F (Fig. 2G). In this way, by cooling the ion source by holding the filament in a heated state until the generation of vapor of the vapor deposition material is reduced after the voltage application is stopped, and then heating the filament is stopped. This can be performed after the amount of vapor generated from the crucible is reduced, whereby the amount of vapor adhering to the ion source can be reduced and the life of the device can be extended. After the termination sequence is completed in this way, a signal is transmitted from the control device 24 to the third DC power supply 16 to turn off the acceleration voltage (FIG. 2H). After that, the apparatus is cooled while the vacuum exhaust apparatus 25 is operating, and then the substrate 14 is taken out.

Although the acceleration voltage, the bombardment voltage, and the ionization voltage are constant after being set in the above embodiment, the values may be changed depending on the film forming conditions.

〔The invention's effect〕

As described above, according to the present invention, the acceleration voltage is first applied before the thermoelectrons are emitted from the filament, so that the filament potential is kept higher than the substrate potential (earth potential). , The substrate and the thin film on the substrate are not damaged by thermoelectrons, and the filament is spun up while monitoring the degree of vacuum, so vapor is ejected below the degree of vacuum that guarantees the performance of the thin film. As a result, not only is the amount of deposition material wasted less, and a highly accurate thin film can be formed with less waiting time required for evacuation until the shutter is opened, and the life of the device is extended. Further, after the vapor deposition, the voltage application to the filament is stopped by gradually lowering the applied voltage, and after the voltage application is stopped, the filament is kept in a heated state until the vapor of the vapor deposition substance is reduced. After that, since the heating of the filament is stopped and the filament is cooled, the amount of the vapor deposition substance attached to each part of the device such as shields is reduced,
There is an effect that the life of the device can be extended.

[Brief description of drawings]

FIG. 1 is a cross-sectional side view showing the present invention and a conventional ICB vapor deposition device, FIG. 2 is a diagram showing a vapor deposition operation sequence of the ICB vapor deposition device according to the present invention, and FIG. 3 is a diagram showing a conventional vapor deposition operation sequence. . In FIG. 1, 1 is a crucible, 5 is a bombarded filament, 8 is an ionized filament,
9 is a grid, 12 is a grid electrode, 13 is an acceleration electrode, 14 is a substrate, 18 is a vacuum chamber, 20 is a DC power supply 7, 11, 16 and AC power supply.
A power supply device for housing 6, 10 is an ionization vacuum gauge, 22 is a film thickness sensor, 23 is a shutter, 24 is a control device for the entire ICB vapor deposition device, and 25 is an exhaust device.

Claims (1)

[Claims] 1. An ICB vapor deposition apparatus having an automatic control operation function, comprising: a monitor means for monitoring the degree of vacuum in a vacuum chamber; and an accelerating voltage applying means for applying an accelerating voltage for accelerating the cluster ions by an electric field. The acceleration voltage is applied by the acceleration voltage applying means, the output of the monitoring means is obtained, and heating and voltage application of the bombarded filament and the ionized filament are performed at a vacuum degree or less at which the performance of the thin film is guaranteed. The application is stopped by gradually lowering the applied voltage, and after the application of the voltage is stopped, the filament is held in a heated state until the vapor of the vapor deposition material is reduced, and then the heating of the filament is stopped. An ICB vapor deposition apparatus comprising a vapor deposition operation sequence control means for cooling by means of cooling.