JPS6342372A - Method for controlling gas flow rate of ion plating device - Google Patents

Abstract

PURPOSE:To permit execution of a stable operation and to improve productivity by adequately introducing a gas for continuing stable discharge and gases for increasing an ionization rate into a vacuum vessel according to the condition at the time of executing ion plating. CONSTITUTION:A reactive gas is supplied from a gas supply source 24 into the vacuum vessel 10 and a film material 14 housed in a crucible 12 is heated and evaporated and is ionized by a discharge electrode 20 by which a thin film is formed on a substrate 16. Provision is made in this operation so that the 1st gas (Ar) for continuing the stable discharge by easily generating the discharge can be supplied from a supply source and the 2nd gases (H2, He) for increasing the ionization rate can be supplied respectively from supply sources 28, 30. These gases are introduced into the vacuum vessel 10 while the flow rates thereof are changed by flow rate controllers 34, 36, 38 according to the operating condition. The control of the controllers 34, 36, 38 is executed by a flow rate control part 42 in accordance with the detected current and voltage of the substrate 16 and the detected current, voltage, etc., of the ionizing electrode 20. The optimum condition meeting the operating condition is thereby created.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is one of the physical steaming methods used for thin film production.
This invention relates to a device for supplying a gas that promotes discharge for ionization to an ion plating device (J3).

(Prior art) An ion plating device evaporates film material (crop and monopole material) from a crucible in a container kept in a substantially vacuum state.
The vapor is ionized by an ionizing electrode, collides with a substrate to which a negative voltage is applied, and forms i[. In an ion plating apparatus, an inert gas such as argon gas (8R) is introduced into a vacuum container to facilitate ionizing discharge (glue discharge).

[Problem that the invention seeks to solve]

However, when only argon gas is introduced into the vacuum volume 2, there is a problem that the discharge load voltage does not increase much, the ionization rate is insufficient, and the quality of the film is not improved.

As a method of increasing the ionization rate by increasing the radiation 1δ voltage, mixing hydrogen gas (H 2 ) or helium gas (He 2 ) into argon gas in an appropriate amount is carried out in an arc gun for plasma melting copper or the like.

However, if it is applied directly to ion plating, the 111 fff starting IM pressure will increase due to the contamination of hydrogen gas or helium gas, and abnormal discharge will occur, causing damage to the substrate being processed or damage to the inside of the crucible. There were problems such as bumping of the membrane material, which made it difficult to start a stable discharge.

In addition, after the start of discharge, the ionization power source and substrate power source were conventionally controlled by constant current control or constant current control, but with constant voltage control the current fluctuates, and with constant current control the voltage changes. Because of the fluctuations, stable operation was not always possible and a homogeneous finished product could not be obtained.

This invention solves the problems in the conventional technology and improves stability and ionization rate at the start of discharge, stability after the start of the market, and improves operational stability and productivity. It is an object of the present invention to provide a gas flow 3 control method for an ion plating apparatus that can be realized.

[Means for solving problems]

This invention provides a method for controlling the flow ω ratio of a first gas, which has the effect of facilitating discharge and continuing stable discharge, and a second gas, which has the effect of increasing the ionization rate, according to the operating conditions. is introduced into the vacuum container by changing the

[For production]

According to the solving means of the present invention, by changing the flow rate ratio of the first gas and the second gas depending on the operating state, it is possible to create an optimal situation depending on the operating state.

That is, for example, at the start of ti1 electric discharge, if the flow rate ratio (first/second) of the first gas and second gas is made large before the start of discharge and small after the start of discharge, the discharge starting voltage can be increased. The ionization rate decreases and stable discharge can be started, and after the discharge starts, the ionization rate increases and productivity can be improved.

Also, after the start of discharge, upstream of the ionization electrode.

By detecting the voltage and the current and voltage of the substrate electrode,
By controlling the flow rate ratio of the first gas and the second gas so that they become predetermined values, it is possible to stabilize the operation after the start of discharge and achieve a homogeneous finish of the product.

〔Example〕

An embodiment of this invention is shown in FIG.

In the figure, a crucible 12 is installed as an evaporation source 11 in the lower part of a vacuum chamber 10, and a membrane material 14 is accommodated therein. This evaporation source 11 includes resistance heating, high frequency heating, 'Fi
The membrane material 14 is heated and evaporated by means such as a subgun.

Above the evaporation source 11, a substrate 16 (the object to be processed,
or the object to be processed is supported on a support plate) is installed. The substrate 16 is set to a negative potential with respect to the evaporation source 11 by the substrate power supply 18 .

A discharge electrode (ionization electrode) 20 for ionization is installed between the evaporation source 11 and the substrate 16. The ionization electrode 20 is set to a positive potential with respect to the evaporation source 14 by ionization ff1ffQ22.

The symbols 24, 26, 28, and 30 indicate gas supply sources (
For example, from the gas supply source 24, T
Nitride and carbide such as iN and TiC.

Nitrogen and hydrocarbons to form films such as oxides.

A chemically reactive gas such as oxygen is supplied. In addition, gas supply a
Argon gas is supplied from 26 as a gas having the effect of easily causing discharge and continuing stable discharge. Also, the gas supply source 28°30 has the effect of increasing the ionization rate. ! Helium gas and hydrogen gas are supplied as gases.

Each gas supply tl! 24, 26, 28, 30 Kara (Jt) Each gas to be G is controlled by gas flow rate control aD2532
．． The gas flows m are respectively controlled at 34.degree.

The flow rate control unit 42 controls the gas flow rate controllers 32, 34, 36, 38 based on the detection of the current and voltage of the long plate 16 and the current and voltage of the ionization source 20 to control the flow rate of each gas. and controls the flow rate ratio of each gas and the total flow rate of all gases.

An example of control in the flow rate control section 42 will be explained.

(1) Example of control at the start of discharge Before the start of discharge, the flow rate of argon gas is increased (for example, the same flow rate as the reaction gas), and the flow rate of hydrogen gas and helium gas is reduced to zero (each flow rate value is determined by the ratio between the total flow rate to be supplied and the flow rate to be set.By a), the discharge starting voltage is lowered (to about 40 V, for example), and the discharge can easily be started at 1".

After the start of discharge, reduce the flow of argon gas (for example, 50% reaction gas + 35% Ar←1 215%), and increase the amount of hydrogen gas or helium gas (in the case of hydrogen gas, usually up to about 30% of the total discharge gas). (In the case of helium gas, the appropriate amount control range is about several percent of the total discharge gas). As a result, the discharge voltage increases to about 90V, and the ionization rate improves. Note that the reaction gas flow m is, for example, a vacuum vessel 1.
Vl tit is set to keep the degree of vacuum within 0 constant.

Detection before or after the start of discharge can be performed, for example, based on the current value of the ionization power source 22.

That is, the current value of the ionization power source 22 is almost zero before the start of discharge due to only dark current, and increases after discharge, so this current value becomes large! Detect one thing and run it
There is a port for switching. Furthermore, regardless of the current value, it is also possible to simply switch the flow rate after a predetermined period of time has elapsed since the operation start command (when it is assumed that the discharge has already started).

(2) Control example after the start of discharge After the start of discharge, a high ionization rate can be obtained even if the flow J is fixed after the switching.

However, the current h4 depends on the discharge state, vapor deposition state, etc.
By adjusting this, it is possible to achieve stable high-quality operation over the entire range of steady-state operation from the start of discharge.

The state of discharge is, for example, ion stationary! The detection length can be determined by the voltage and current of 22. Further, the state of vapor deposition can be detected, for example, by the voltage and current of the substrate power supply 18.

That is, when the ion fixing devices 11 and 22 are subjected to constant voltage control, the flow rate of each gas is controlled by detecting the current. That is, for example, if the current value becomes larger than a set value, argon gas is decreased and hydrogen gas or helium gas is increased. Conversely, if it becomes smaller than the set value,
Increase argon gas and avoid decreasing hydrogen and helium gas.

Further, when the ionization source 22 is controlled by constant current, the voltage is detected to control the flow rate of each gas. For example, if the voltage value becomes larger than the set value, argon gas is increased and hydrogen gas or helium gas is decreased. Conversely, if the value becomes smaller than the set value, argon gas is decreased and hydrogen gas or helium gas is increased.

If the substrate power supply 18 is controlled by a constant voltage, the current is detected to control each gas flow h). That is, for example, if the current value is set (1 (I),
This means that ionization is occurring intensely, so increase argon gas and decrease hydrogen gas or helium gas3.Also, if the current value becomes smaller than the set value, ionization will be less, but argon gas decrease,
Increase hydrogen gas or helium gas.

The above flow control after the start of discharge can be performed by correcting the flow rate set value for switching as described in (1) above using the detected current (1f1) or voltage value. It is also possible to perform the process using only the current value or voltage value detected regardless of the current value or voltage value.

Through the flow mother control described above, the ionization power source 22. Board power supply 1
8 can perform up to constant voltage control if constant current control is performed, and can perform up to constant current control if constant voltage control is performed. As a result, stable operation with high ionization efficiency is realized.

J7, the above flow m811riU is the ionization power source 22.
This can be done based on either or both of the substrate power supplies 18. Ionization? If there is no [, it is performed based on the board power supply.

By the way, the entire apparatus shown in FIG. 1 operates as follows.

■ After evacuating the vacuum ¥ff1Ti1Q and cleaning the normal substrate 16 with ions, ion plating is started.

■ Evaporation [When power is applied to 11 and evaporation starts, 11
At 1 o'clock or a little later, the reaction gas is introduced at a preset flow rate. Furthermore, argon gas is introduced in substantially the same flow M as the reaction gas. At this time, the flow rate of hydrogen gas or helium gas is set to O or 9.

■ Ionization power supply 22 J3 J by giving discharge start command
: Then turn on the board power supply 18 and start discharging. Since the flow rate of argon gas is large, discharge starts at a low voltage.

■ When the start of discharge is detected from the current value, etc. (=) of the ionization power source 22, or when the time from the discharge start command that is assumed to have already started has elapsed,
Decrease argon gas and increase hydrogen gas and helium gas.

(2) After the start of discharge, the gas flow Bl ratio is controlled based on the current value or voltage value of one or both of the ionization power source and the substrate power source 18 so as to maintain a constant voltage and constant current. This achieves efficient and stable operation.

[Example of change]

In the embodiments described above, the gas flow rate is controlled based on the pressure of the power source, the current, or the elapse of a set time, but it can also be controlled based on detection elements such as the temperature of the electrodes or the substrate.

Furthermore, although the above embodiments have shown the case where the present invention is applied to ion plating using a reactive gas, the present invention can also be applied to ion plating that does not use a reactive gas.

〔Effect of the invention〕

As explained above, according to the present invention, the first
This gas and a second gas that has the effect of increasing the ionization rate are introduced into the vacuum vessel by changing their flow rates according to the operating conditions. You can create situations.

For example, at the time of starting discharge, if the flow rates (first/second) of the first gas and second gas are set high before the start of the fit telegram and small before the beginning of the discharge [1i1], then the The voltage is lowered and a stable discharge can be started, and after the discharge starts, the ionization rate increases and productivity can be improved.

Also, after the start of discharge, the current of the ion electrode.

Detect the voltage and the current and voltage of the curtain electrode, respectively.
By setting the flow M ratio of the first gas and the second gas to υJl so that they become predetermined values, it is possible to stabilize the operation after the start of discharge and achieve a homogeneous finish of the product. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. 10... Vacuum container, 11... Evaporation source, 12... Crucible, 14... Membrane material, 20... Ion electrode, 16...
·substrate.

Claims (3)

[Claims] (1) Change the flow rate ratio of the first gas, which has the effect of facilitating discharge and continuing stable discharge, and the second gas, which has the effect of increasing the ionization rate, depending on the operating conditions. 1. A gas flow rate control method for an ion plating apparatus, characterized in that the gas is introduced into a vacuum container. (2) At the time of starting the discharge, the flow rate ratio (first/second) of the first gas and the second gas is increased before the start of the discharge and is decreased after the start of the discharge. A gas flow rate control method for an ion plating apparatus according to item 1. (3) After the discharge starts, the current and voltage of the ion electrode and the current and voltage of the substrate electrode are respectively detected, and the flow rate ratio of the first gas and the second gas is controlled so that they become predetermined values. A gas flow rate control method for an ion plating apparatus according to claim 1, characterized in that: