JPS59232268A - Vacuum device - Google Patents

Abstract

PURPOSE:To restore quickly atm. pressure without soar-up of dust in a vacuum vessel by feeding high pressure air into the vessel by using a fluid throttling valve device having a specific construction. CONSTITUTION:Air is fed into a vacuum vessel 601 from a high pressure air source 606 via a fluid throttling valve 607 and a stop valve 605 in the stage of supplying the air to said vessel and restoring the atm. pressure therein after finishing a vacuum deposition treatment with a vacuum deposition device. A pressure detector 609 is installed in the vessel 601, and such a deviation signal 613 at which the deviation between the pressure signal 611 detected with said detector and the signal 612 from a pressure commanding means 610 is made zero. The means 610 emits such a command 612 as to decrease gradually the restrictor of the valve 607 to an optimum condition in order to maintain the required change rate of the pressure in the vessel 601 with time. The above- mentioned deviation signal 613 is converted by a preamplifier 614 to a speed command signal 615 which is amplified by an amplifier 616. A motor 617 for driving the valve 607 is driven by said signal so that the air is fed to the vessel so as to meet the prescribed air feeding characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to the structure of a vacuum apparatus used for vacuum evaporation and the like.

Structure of conventional examples and their problems In recent years, vacuum evaporation technology has become indispensable to the semiconductor and optical industries, and plays a major role in thin film formation technology.

A vacuum evaporation apparatus is composed of two parts: a vacuum apparatus and a heating source for heating and evaporating a evaporation source. As shown in FIG. 1, the vacuum device is composed of a container 101, an exhaust means 102 for evacuating the inside of the container, and an air supply means 103 for supplying gas into a well-vacuumed container and bringing it to atmospheric pressure. There is. Normally, the air supply means 103 is composed of a fluid throttle valve 104 and an air supply on/off valve 105 that are connected in series.The fluid throttle valve 104 regulates the air supply speed in its throttled state, and the air supply The on-off valve 105 determines the start and end of air supply.

Figure 2 is an example of the relationship between pressure and time obtained experimentally when air is supplied to a container in a vacuum state with the throttle state of each fluid throttle valve (flow path resistance R). The rate of change in pressure over time is constant, but as the pressure approaches atmospheric pressure, this rate of change gradually decreases.

In recent years, there has been a trend toward dust-free vacuum deposition, and it is often necessary to perform deposition in a highly clean atmosphere. In vacuum evaporation, the entire evaporated film is the object to be evaporated.

Although there is no problem if the vapor is deposited only on the location to be vapor-deposited, the result is that the vapor-deposited film also adheres to other locations within the container.

As the vapor deposition is repeated, the vapor deposited film deposited inside the container tends to peel off and accumulate at the bottom of the container, or to easily peel off if not peel off. If air is supplied into the container under such conditions, the sudden inflow of gas will cause
Dust from vapor deposits, etc. that has accumulated at the bottom of the container will fly around.
It adheres to the object to be evaporated in the container, resulting in contamination of the object to be evaporated. As a countermeasure against this problem, it is effective to increase the flow path resistance of the fluid throttle valve 104 shown in FIG. On the other hand, the drawback is that it takes a very long time to supply air.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional problems.When air is supplied to a vacuum container such as a vapor deposition apparatus, dust attached to the container or accumulated at the bottom is blown up by the gas flow. In addition to preventing contamination of the material to be deposited in the container,
It is an object of the present invention to provide a vacuum device that can shorten the time required for air supply to reach atmospheric pressure as much as possible.

a gas supply means for supplying gas at a pressure higher than atmospheric pressure; and a fluid whose flow path resistance gradually decreases over time, the gas supply means being inserted between the gas supply means and the container. It consists of a throttle means and an air supply opening/closing valve connected in series to the fluid throttle means, and prevents dust from flying up at the beginning of the air supply.The gas supply means supplies gas at a pressure higher than atmospheric pressure for a short time. This completes the air supply to the container.

Description of examples Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a diagram showing the principle of this, and shows a container 301 in a vacuum state.
When supplying air to atmospheric pressure, a gas supply means 306 that supplies gas at a pressure higher than atmospheric pressure is connected to the container 301 via an air supply opening/closing valve 305 and a fluid restriction means 304 connected in series. FIG. 4 shows the fluid restricting means 304 in FIG.
The pressure and time when a container in a vacuum state is inflated by fixing the flow path resistance and supplying gas at atmospheric pressure and gas at a higher pressure than atmospheric pressure, for example, 2 atmospheres, as the gas supply means 306. This is a comparison of the relationship between

In FIG. 4, A indicates a case where the pressure of the gas in the gas supply means is atmospheric pressure, and B indicates a case where the pressure is 2 atmospheres.

When gas is supplied at atmospheric pressure, as it approaches atmospheric pressure,
The rate of change in pressure over time becomes smaller and the time required to supply air to reach atmospheric pressure becomes longer, but if 2 atm gas is supplied, the rate of change in pressure over time becomes almost uniform at the same atmospheric pressure. This allows the air supply time to be shortened. By supplying gas at a pressure higher than atmospheric pressure in this manner, it is possible to improve the phenomenon in which the rate of change in pressure over time decreases as the pressure approaches atmospheric pressure, and the air supply time can be shortened.

FIG. 4 is an explanatory diagram when the flow path resistance of the fluid restricting means is fixed as described above, and the rate of change of the pressure at the beginning of air supply with respect to time is relatively large. Therefore, at the beginning of air supply, due to the rapid inflow of gas, the container 301
The dust inside will fly up, resulting in contamination of the object to be deposited. As a countermeasure against this problem, as shown in FIG. 3, the fluid restricting means 304 is constituted by a fluid restricting valve 307 and a restricting valve driving means 308 that opens the restricting valve of the restricting valve 307 at a predetermined speed to reduce the flow path resistance of the fluid restricting valve 307. It was gradually reduced over time. In other words, at the beginning of the air supply, the fluid restrictor or valve is sufficiently throttled to increase the flow path resistance so as to ensure that dust does not fly up, and then the flow path resistance is gradually decreased.
The relationship between pressure and time shown in FIG. 6 is realized. As a result, in addition to preventing dust from flying up, the synergistic effect with the gas supply means having a pressure higher than atmospheric pressure shortens the air supply time until atmospheric pressure is reached. Note that when the inside of the container 301 reaches the atmosphere during air supply, the air supply on/off valve 305
By providing a means for closing the air pressure supply means, it is possible to effectively utilize the supplied gas in the atmospheric pressure supply means.

A sixth throttle valve driving means opens the throttle of the throttle valve between the container and the gas supply means having a pressure higher than atmospheric pressure at a required speed.
The device shown in the figure is very effective.

A pressure detection means 609 for detecting the pressure inside the container 601 and a pressure command means 610 for instructing the throttle of the fluid throttle valve 607 to be gradually reduced under optimum conditions in order to obtain a desired rate of change of the pressure inside the container with respect to time are provided. , pressure detection means 609
A pressure deviation signal 613 is extracted that makes the deviation between the pressure signal 611 from the pressure command means 610 and the pressure command signal 612 from the pressure command means 610 zero. This pressure deviation signal 613 is converted into a speed command signal 615 via a preamplifier 614 and further amplified by a motor drive amplifier 616 to drive a motor 617 directly connected to the throttle of the fluid throttle valve 607.
This method gradually reduces the flow path resistance of
Predetermined air supply characteristics can be obtained with high precision.

As the fluid throttling means for gradually reducing the flow path resistance over time, the method described above uses a throttling valve drive means that opens the throttling valve at a required speed, but the following method is also effective. This includes a plurality of air supply on/off valves 7 as shown in FIG.
0.5a, 7otsb...705n and different fluid restrictors 707a connected in series to each of these air supply on/off valves 705a, 705b...705n.
, To'''rb-707n are connected in parallel, from the fluid restrictor with large flow path resistance to the fluid restrictor with small flow path resistance.
By means of an on-off valve operation means 708 that sequentially opens the air supply on-off valves connected thereto, the flow path resistance of the entire fluid restriction system is gradually reduced over time.

Note that in FIGS. 3, 6, and 7, which are explanatory diagrams of the present invention, the air supply means are all arranged in the second part of the container.
This is very effective in making it difficult for dust accumulated in the container to be blown up in the air supply.

Effects of the Invention As described above, the vacuum device of the present invention, when supplying air to atmospheric pressure in a container in a vacuum state, connects the gas supply means for supplying gas at a pressure higher than atmospheric pressure to the air supply opening/closing system connected in series. Since the valve is connected to the container through a fluid restricting means whose flow path resistance gradually decreases over time, it is possible to prevent dust from flying up due to the large flow of gas at the beginning of air supply, and to prevent Tll staining on the material to be evaporated. At the same time, the time required for air supply to reach atmospheric pressure is also greatly shortened, and its industrial value is extremely large.

[Brief explanation of drawings]

Fig. 1 is a principle diagram of a conventional vacuum device, Fig. 2 is a characteristic diagram showing the relationship between the pressure inside the container and air supply time when the flow path resistance of the throttle valve of the same device is constant, and Fig. 3 is a diagram showing the relationship between the pressure inside the container and the air supply time. FIG. 4 is a principle diagram showing the outline of a vacuum device according to an embodiment of the present invention, and FIG. A characteristic diagram showing the relationship between internal pressure and air supply time, Fig. 5 is a diagram showing the relationship between the internal pressure of the container and air supply time of the same device, and Fig. 6 is a blow diagram of a more specific embodiment of the present invention. , FIG. 7 is a block diagram showing an embodiment of the same. 301.601.701 ・-・・=container, 307,6
07゜70了1,7072...707n...
Fluid throttle valve, 305°605.6051.6052-・
・605n-・-Air supply opening/closing valve, 306. θ○6.706
. . . Gas supply means, 308 . . . Throttle valve driving means, 708 . . . Air supply opening/closing valve operation means. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 2 Haruyoshi Yarihisa Figure 3 Figure 4 # Long time L Figure 5 Endurance time Figure 6 Figure 7

Claims (5)

[Claims] (1) A container, and an air supply means for supplying gas into the container in a vacuum state to bring the inside of the container to atmospheric pressure, and the air supply means is provided with a gas having a pressure higher than atmospheric pressure. Consisting of a gas supply means, a fluid throttle means inserted between the gas supply means and the container and whose flow path resistance gradually decreases over time, and an air supply opening/closing valve connected in series to the fluid throttle means, A vacuum device configured to close the air supply opening/closing valve when the inside of the container reaches atmospheric pressure. (2) The vacuum device according to claim 1, wherein the fluid restricting means is constituted by a variable restricting valve and a restricting valve driving means that opens the restricting valve at a required speed. (3) A pressure detection means for detecting the pressure inside the container, a pressure command means for commanding the pressure inside the container to gradually decrease at a required speed, and a pressure signal from the pressure detection means for controlling the throttle valve driving means. 3. The vacuum apparatus according to claim 2, further comprising throttle valve control means for driving said throttle valve so that the deviation of the pressure command signal from said pressure command means is zero. (4) The fluid control means is a fluid having a large flow path resistance between a plurality of air supply on-off valves and a fluid restrictor having a mutually different flow path resistance and connected in series to each of the plurality of air supply on-off valves. 2. The vacuum device according to claim 1, further comprising an on-off valve operating means that sequentially opens on-off valves connected to the fluid throttle having a small flow path resistance, starting with the on-off valves connected to the throttle. (5) The vacuum device according to claim 1, wherein the connection portion between the air supply means and the container is arranged in the second part of the container.