JPS63153268A - Method for controlling partial pressure of gas in continuous dry coating tank - Google Patents

Abstract

PURPOSE:To stably and simply control the partial pressure of reactive gases in a coating tank by setting the ratio between the flow rates of the gases, comparing the detected internal total pressure of the coating tank with the desired pressure and regulating the total flow rate of the gases. CONSTITUTION:The ratio between the flow rates of reactive gases such as N2 and Ar is set at the optimum value. When the internal total pressure of an IP device 2 measured with a vacuum gauge V is lower than the desired degree of vacuum for operation, a PID controller and a proportional amplifier K output a signal for increasing the flow rates of the gases. By the signal, the flow rates of the gases flowing through mass flow controllers 12 are increased so that the internal total pressure of the device 2 is made close to the desired degree of vacuum for operation. When the internal total pressure of the device 2 is higher than the desired degree of vacuum, the PID controller and the amplifier K output a signal for reducing the flow rates of the gases. By the pressure control, the ratio between the amts. of the gases in the device 2 is made nearly uniform and the partial pressures of the gases in a coating tank can be made nearly constant.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for controlling gas partial pressure in a continuous dry coating tank in which ion blating, sputtering, etc. are continuously applied to a strip or the like using a relatively simple device. It is something.

Conventional technology In recent years, coating technologies using dry processes such as ion blating and sputtering have been increasingly used to modify the surface of metal substrates. Titanium and titanium nitride coatings are frequently used. In these processes, multiple types of reactive gases such as nitrogen gas and acetylene and carrier gases such as argon are introduced into a vacuum coating tank, and electrical discharge energy is used to react with metal atoms in the tank to coat the substrate.

Perform the

When a plurality of gases as described below are introduced into a chamber and reacted, the quality of the coating tank, which is a product of the reaction, is greatly influenced by the partial pressure of the reaction gases. Conventionally, these partial pressures have not been actively controlled, and the method has been to change the exhaust volume of the coating tank and the amount of gas introduced through trial and error, and fix the gas volume to a level that provides good coating quality.

Problems to be Solved by the Invention In the prior art described above, it took a lot of time to determine the optimum vapor deposition conditions because a plurality of gas conditions were determined by trial and error.

Furthermore, when changing the operating pressure by changing the displacement amount of the coating tank, there were problems in operability, such as the need to readjust the total number of introduced gases.

In addition, when coating a single coating tank in a batch type tank, it was possible to use the conventional technology described above, but when coating by continuously passing a strip, etc., it is necessary to use another vacuum such as a differential pressure seal. Gas flows into the tank exhaust system, which may disturb the gas pressure in the coating tank and prevent the desired coating from being obtained.

An object of the present invention is to obtain a stable and high-quality coating in continuous dry coating by stably and easily controlling the partial pressure of a reaction gas that influences coating quality.

Means/Function for Solving the Problems The present invention provides a method for coating a material by continuously passing a material through a vacuum coating tank while introducing a plurality of gases into the coating tank. The present invention is characterized in that the flow rate ratio of the gases is determined in advance, the total pressure within the coating tank is detected, and the total flow rate of the plurality of gases is adjusted based on a comparison between the detected value and a target pressure.

Dry coating in the present invention refers to dry coating on the surface of a material using a solid substance that serves as a coating tank and a plurality of gases (a gas that serves as a coating tank and a carrier gas) in a vacuum chamber. ), sputtering (hereinafter referred to as SP
), etc., and the target is one in which each of these coating tanks is continuously arranged singly or in combination.

Control in the present invention is achieved by installing a vacuum gauge for detecting the total pressure inside the tank and a plurality of mass flow controllers for each type of gas in the coating tank to maintain a predetermined operating pressure, thereby configuring a closed-loop control system. , the degree of vacuum in the coating tank is controlled at a constant level. When applying to multiple coating tanks, a closed loop control system is configured for each coating tank.

The method of the present invention will be explained below using an example of the apparatus shown in the drawings.

In Figure 1, an ion brating device 2 (hereinafter referred to as IP device), a differential pressure sealing device 3, and a plasma CVD device 4 (hereinafter referred to as P-CVD device) are installed between two unwinding and winding devices 1.1. The device 2, the differential pressure seal device 3, and the P-CVD device 4 are installed in series in this order, and these devices are housed in a vacuum container 5 in communication with each other, and the strip S, which is the material to be coated, is
This is an example in which the present invention is applied to an IP device 2 of equipment in which a different type of film is coated on the surface of a film while it passes through an IP device 2 and a P-CVD device 4. In Figure 1, 6 is the target, 7 is the preheater, 8 is the gas inlet, and 9 is the IP
An apparatus heater, 10 is a P-CVD apparatus heater, and 11 is a slit.

Horse gas as a reactive gas and Ar gas as a carrier gas are introduced into the IP device 2 via a mass flow controller 12. Further, a vacuum gauge v for detecting the total pressure of gas within the IP device 2 is installed.

The mass flow controller 12 is of a type in which the amount of gas passing through the introduction pipe can be adjusted by an external electric signal. The mass flow controller 12 and the vacuum gauge V are connected to a control system composed of a PID controller PID with proportional, integral, and differential operations and a proportional amplifier K.

A coil of the strip S is attached to either one of the unwinding and winding devices 1.1, one end of the strip S is attached to the other, the inside of the vacuum container 5 is evacuated by the vacuum pump P, and coating is attempted. Raise the vacuum level to a level lower than the operating vacuum level.

Next, the closed-loop control system for the operating vacuum level is operated, and a reactant gas and a carrier gas are introduced via the mass flow controller 12. The amounts of these two types introduced are adjusted as follows.

The flow rate ratio of N and Ar is determined by setting the gain of the proportional amplifier to the optimum flow rate ratio obtained experimentally in a batch coating apparatus.

When the control of the present invention is started, when the total pressure inside the IPP station 2 measured by the vacuum gauge V is lower than the target value of the operating vacuum degree, the output to the PID controller PID and the proportional amplifier will change depending on the increase in the gas amount. A signal is generated, and in response to this signal, the amount of gas flowing through the mass flow controller lz increases, and the vacuum level in the tank approaches the target operating vacuum level.

Conversely, when the pressure inside the IPP unit 2 is higher than the target operating vacuum level, the output to the PID controller PID and the proportional amplifier will issue a signal to reduce the gas amount, and the internal vacuum level will approach the target operating vacuum level. .

While the total pressure is controlled as described above, the ratio between the amount of N gas and the amount of At gas inside the IP equipment remains almost constant, and while the predetermined operating vacuum level is maintained, the gas partial pressure inside the tank also remains almost constant. Constantly adjusted.

In this device, even if the gas in the IPP device 2 is sucked into the differential pressure sealing device 3, the partial pressure of the gas in the IPP device 2 is kept almost constant.
The operating vacuum inside the container is less likely to be disturbed, and stable coating can be obtained in the IPP device 2.

Examples Example 1 Ti is continuously applied to the surface of a stainless steel strip using an IP device.
An example in which the present invention is implemented in a N coating process will be shown.

While passing a 304 series stainless steel strip with a thickness of 0.5 fat and a radius of 30 Gmm at a line speed of 0.1 layer/min, IP
The device uses Ti as the evaporation source, hollow cathode gun method 1 as the evaporation method, horse as the reactive gas, and Ar as the carrier gas.
was used to coat TiN.

At this time, the target value of the operating vacuum level is set to 1O-3Torr, N
2. By using the control method of the present invention with an Ar flow rate ratio of 1:4, the N2 flow rate is 20SCCH, the Ar flow rate is
805 CCN, the operating vacuum was maintained at 1 O-3 Torr, and a TiN film of good quality was obtained.

Example 2 Using an SP device, Ti was continuously applied to the surface of a stainless steel strip.
In the N coating process, the line speed and material to be coated were the same as in Example 1, showing an example in which the present invention was implemented.

Ti is used as the target material of the SP device, and N is used as the reaction gas.
2. Ar was used as a carrier gas.

At this time, the target value of the operating vacuum level is 5XlO-'Torr.
, the flow rate ratio of N2 and Ar was set to 3nea. By using the control method of the present invention, the flow rate is 15SCCH, Ar
Flow rate 35SCCM, operating vacuum level 5XlO-3Torr
A TiN film of good quality was obtained.

Example 3 The IP equipment side of the combined process of the IP equipment and the P-CVD equipment shown in Fig. 1 shows an example in which the present invention is applied.The coating material was Tie in the IP equipment and amorphous 5i02 in the P-CVD equipment. Two layers of TiN and amorphous 5i02 were coated continuously. The line speed and material to be coated were the same as in Example 1 above.

The evaporation source, evaporation method, and gas used in the IP apparatus were the same as in Example 1. In addition, in the P-CVD equipment, a mixed gas of SiH4 and N20 is maintained at a vacuum level of approximately 0.5 Torr.

Amorphous 5i coated with TiN by high frequency discharge
02 was coated.

As a result of applying the present invention with the Ar flow rate ratio of the core of the IP device set to 1:4 and the target value of the operating vacuum level to 1O-3 Torr, the horse flow rate was approximately 25SC:CM, and the Ar flow rate was 11005.
CC, the operating vacuum was maintained at 10-3 Torr.

As a result of applying the present invention, high quality Ti can be deposited on stainless steel.
Amorphous 5i07 coated with N film
A two-layer coating of good quality was obtained.

Effects of the Invention According to the present invention, a continuous dry coating such as ion blasting or sputtering can be stably formed with good quality, and it is possible to manufacture a strip coil product with good coloring properties and corrosion resistance.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of equipment for carrying out the method of the present invention. 1... Unwinding and winding device, 2... Ion brating device, 3... Differential pressure sealing device, 4... Plasma CV
D device, 5... vacuum container, 6... target, 7.
... Preheating heater, 8... Gas inlet, 9... IP device heater, lO... P-CVD device heater, 11...
・Slit, 12...Mass flow controller, P.
...Exhaust % device, S...Strip plate, ■...Vacuum gauge, PID
...PID controller, K...proportional amplifier.

Claims (1)

[Claims] In a method for coating a material by continuously introducing a plurality of gases into a vacuum coating tank and passing the material through the coating tank, the flow rate ratio of the plurality of gases is determined in advance, and 1. A gas partial pressure control method for a continuous dry coating tank, characterized in that the total flow rate of the plurality of gases is adjusted based on a comparison between the detected value and a target pressure.