JPH0977144A - Vacuum container leak flow controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow rate controller for leak of vacuum container which prevents particles from stirring up and achieves a high throughput, on opening the vacuum container to the open air. SOLUTION: This controller is provided with a flow rate detector 11 installed in a leak line of a vacuum container and a flow rate controller 12 controlling the flow rate detector to vary the leak stepwise. The controlled leak is made small at the start of leak and the leak is increased in accordance with the pressure of vacuum container.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum container leak flow controller for controlling the leak flow rate when a vacuum container is leaked and opened to the atmosphere.

[0002]

2. Description of the Related Art In a vacuum container such as an LCD plasma CVD apparatus, particularly a load lock chamber, an object to be processed is carried in,
When being carried out, the vacuum container is always opened to the atmosphere.
In order to perform the opening to the atmosphere, the vacuum container is provided with a leak line for leaking gas to open to the atmosphere, and a flow rate control device is provided on the leak line. FIG. 3 shows a conventional example of this type of vacuum vessel leak flow control device. FIG.
FIG. 3 is a system diagram of an example of a flow rate control device.

An object to be processed is carried into the vacuum container 2, the vacuum container 2 is evacuated through the vacuum line 4, and the object to be processed is processed under vacuum in the previous period. A leak line 7 is communicated with the vacuum container 2, and a flow rate detector 11 that is opened by an electric signal is provided in the leak line 7. After processing the object to be processed, when the vacuum container 2 is opened to the atmosphere, the main exhaust valve 5 of the vacuum line 4 is closed and the flow rate detector 1
1 is opened, leak gas is flown into the vacuum container 2 through the leak line 7, and the vacuum container 2 is leak-pressurized. In this case, a flow rate setting signal is input to the flow rate detector 11, a leaking flow rate is set to a predetermined constant value, and a gas whose flow rate is controlled to be constant by the flow rate detector 11 flows into the vacuum container 2. The vacuum container 2 is then opened to the atmosphere. In the figure, 3 is a pressure detector, and 6 is an exhaust device including a vacuum pump and the like.

[0004]

However, in the above-mentioned prior art, since the vacuum container leaks to the atmosphere by constant flow rate control and is opened to the atmosphere, the control is facilitated, but the following problems occur. There is. That is, in order to realize high throughput as the entire apparatus, it is preferable that the time required for opening to the atmosphere is as short as possible, and for that purpose, a large flow rate of gas may be passed through the vacuum container. However, when the flow rate is set to be large, the particles in the vacuum container are rolled up, and the object to be processed is contaminated with the particles. Further, if the flow rate is narrowed and set to a small value, the time required for opening to the atmosphere becomes long and the throughput is lowered.

In view of the above situation, it is an object of the present invention to provide a vacuum container leak flow rate control device capable of suppressing winding of particles when the vacuum container is opened to the atmosphere and achieving high throughput.

[0006]

The present invention comprises a flow rate detector provided in a vacuum vessel leak line, and a flow rate control section for controlling the flow rate detector to change the leak rate stepwise. The leak amount to be controlled is a small flow rate at the start of the leak, and the leak amount is increased corresponding to the increase of the vacuum container pressure value. Further, the flow rate control unit has the leak amount for the vacuum container pressure value as table data. That is
At the start of the leak, the control flow rate of the flow rate detector is set small, and the control flow rate of the flow rate detector increases stepwise as the pressure of the vacuum vessel increases, and a large amount of gas flows into the vacuum vessel. To quickly open the atmosphere to high throughput.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram showing an embodiment of a flow control device for vacuum container leak according to the present invention, and FIG. 2 is a diagram showing a pressure-flow rate table. Vacuum processing device 1
Is a vacuum container 2 in which an object to be processed is loaded and processed under vacuum.
A pressure detector 3 for detecting the pressure p, a vacuum line 4 for exhausting, and a leak line 7 for opening to the atmosphere are connected to the vacuum container 2. The vacuum line 4
A main exhaust valve 5 and an exhaust device 6 are provided in the.

The leak line 7 is provided with a flow rate detector 11 which is opened and closed by an electric signal.
A flow rate control unit 12 for setting a leaking flow rate is connected to the so as to automatically control the flow rate.

The flow rate control unit 12 comprises a controller 13, a comparator 14, a changeover switch 15 and a data manipulator 16. The controller 13 is connected to the comparator 14, and the comparator 14 is switched. The flow rate detector 11 and the data operation unit 16 are connected via the switch 15, and the changeover switch 15 changes the connection state of the comparator 14, the flow rate detector 11 and the data operation unit 16. A feedback signal f is input to the controller 13 from the data manipulator 16, and a signal p from the pressure detector 3 is input to the comparator 14.
Is input.

A pressure-flow rate table is preset and input to the data manipulator 16. In the pressure-flow rate table, for example, the flow rate is increased stepwise with an increase in pressure as shown in FIG. It is set to increase the amount of increase in Q.

Next, the operation will be described. During vacuum processing, the vacuum container 2 into which the object to be processed is carried is closed.
When the flow rate detector 11 is closed, the main exhaust valve 5 is opened, and the exhaust device 6 is operated, the vacuum container 2 is evacuated by the exhaust device 6. The vacuum container 2 is set to a predetermined degree of vacuum, and in the vacuum atmosphere, the object to be processed is subjected to various kinds of processing under vacuum.

When the vacuum container 2 is opened to the atmosphere when the object to be processed is carried out after the vacuum processing, the main exhaust valve 5 is closed and the controller 13 of the flow rate controller 12 is opened to the atmosphere signal s. Enter. When the air open signal s is input, the controller 13 presets the initial flow rate value and the initial pressure value in the comparator 14. The comparator 14 outputs a drive signal to the flow rate detector 11 according to the preset value to operate the flow rate detector 11. The initial flow rate value is a flow rate value that is sufficiently small so that the particles are not rolled up in the vacuum container 2 when the leak gas flows in. At this time, the changeover switch 15 connects the comparator 14 to the flow rate detector 1 through the a contact.
Connected to 1.

The pressure inside the vacuum container 2 rises as the leak gas flows in. The pressure value P is detected by the pressure detector 3 and input to the comparator 14. A preset value is compared with the pressure value P in the comparator 14, and when the pressure value P matches the preset value, a coincidence signal is output to the controller 13. The controller 13 switches the changeover switch 15 to the b contact, and reads the leak flow rate setting value and target pressure value in the next step from the data operating device 16. The flow rate set value and the target pressure value are determined by the pressure-flow rate table as described above.

The read flow rate setting value and target pressure value are input to the comparator 14, the preset value is updated, and the changeover switch 15 is changed to the a contact side. The comparator 1
4 controls the flow rate of the flow rate detector 11 according to the updated set value.

Thus, each time the pressure in the vacuum container 2 reaches the target pressure value, the above-described operation is repeated to open the atmosphere.

Thus, in the initial stage when the pressure p of the vacuum container 2 is low, the flow rate controlled by the flow rate detector 11 is small,
The gas is suppressed from flowing into the vacuum container 2 and the pressure gradually rises to prevent particles from being wound up. As the pressure p of the vacuum container 2 increases, the flow velocity for the same inflow flow rate decreases, so the control flow rate is gradually increased. Since a large amount of gas flows into the vacuum container 2, the rate of pressure increase increases, the vacuum container 2 is quickly opened to the atmosphere, and high throughput is achieved.

Although the embodiment of the present invention has been described above, the contents of the pressure-flow rate table are not limited to the embodiment. Other control elements can be added to the table.

[0018]

As described above, according to the present invention, the leak flow rate is small at the start of the leak, and after the leak starts, the leak flow rate is increased stepwise in accordance with the increase of the pressure in the vacuum container. It is possible to suppress winding of particles and achieve high throughput.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a vacuum container leak flow rate control device according to the present invention.

FIG. 2 is a diagram showing a pressure-flow rate table.

FIG. 3 is a system diagram showing an example of a conventional flow rate control device.

[Explanation of symbols]

 2 Vacuum container 3 Pressure detector 7 Leak line 11 Flow rate detector 12 Flow rate control unit

Claims (3)

[Claims] 1. A flow rate for a vacuum vessel leak, comprising: a flow rate detector provided in a vacuum vessel leak line; and a flow rate control unit for controlling the flow rate detector to change the leak rate stepwise. Control device. 2. The flow control device for a vacuum container leak according to claim 1, wherein the controlled leak amount is a small flow amount at the start of the leak, and the leak amount is increased corresponding to the increase of the vacuum container pressure value. 3. The vacuum vessel leak flow rate control device according to claim 1, wherein the flow rate control unit includes a leak amount for the vacuum vessel pressure value as table data.