JPH074515B2 - Operating method of vacuum processing equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vacuum evacuation device, and in particular, to vacuum evacuation while adsorbing and removing a high-temperature boiling point fluid, and operation of a vacuum processing device suitable for vacuum processing of a sputtering device. It is about the method.

[Conventional technology]

Conventional devices are described in U.S. Pat.
It consists of a rotary pump, an oil diffusion pump, and a liquid nitrogen trap. The liquid nitrogen trap holds liquid nitrogen inside and exposes its cooling surface to the exhaust pipe that connects the exhaust chamber and the oil diffusion pump. Moisture or CO ₂ or other high boiling point gas that cannot be exhausted sufficiently by the diffusion pump, or a substance that deteriorates the performance of the oil diffusion pump, such as chlorine gas or organic solvent vapor, is condensed and solidified on the cooling surface. It was supposed to trap. Further, since the liquid nitrogen in the liquid nitrogen trap constantly evaporates by the amount of heat intrusion, the liquid nitrogen is replenished periodically to keep the liquid nitrogen trap at a low temperature all the time.

[Problems to be solved by the invention]

The above-mentioned prior art does not take into consideration maintainability and controllability. If liquid nitrogen replenishment work is neglected, the trap temperature rises and exhaust performance deteriorates, or trapped gas rises and the exhaust chamber is exhausted. However, since liquid nitrogen was used to cool the trap, the cooling temperature was almost constant at 77K, and the gas to be trapped could not be selected.

An object of the present invention is to keep the cooling plate at a low temperature all the time to maintain the exhaust performance and prevent the trapped gas from rising,
It is an object of the present invention to provide a method for operating a vacuum processing apparatus that can reduce the consumption of argon gas.

[Means for solving problems]

The above-mentioned object is a temperature controllable cooling plate which is provided in the middle of an exhaust pipe connecting a vacuum processing chamber to which an argon gas is supplied as a processing gas and a vacuum pump, and which is cooled by a refrigerator.
It is provided with a gate valve provided between the exhaust pipe and the vacuum pump for adjusting the exhaust flow rate of the vacuum processing chamber, and after evacuation to a predetermined high vacuum region, the temperature of the cooling plate is controlled to about 32K by the refrigerator, This is achieved by adsorbing and removing the gas having a boiling point higher than the temperature of the cooling plate by the cooling plate, and then adjusting the exhaust amount of the remaining gas by controlling the opening degree of the gate valve.

[Action]

Since the cooling plate is always kept at a low temperature during the freezing operation of the refrigerator, there is no need to use liquid nitrogen, so there is no problem due to forgetting to supply it, and the exhaust performance is maintained to prevent the trapped gas from rising. You can

Also, by controlling the temperature of the cooling plate to about 32K,
Except for argon in the exhausted chamber (vacuum processing chamber), that is,
It is possible to reduce the consumption of argon gas by adsorbing and removing the high-boiling-point gas having a temperature of 30 K or higher, and squeezing the gate valve in this state.

〔Example〕

 An embodiment of the present invention will be described below with reference to FIG.

The exhausted chamber 1 has an exhaust port 2, and the exhaust port 2 is an exhaust pipe. In this case, a T-shaped vacuum duct 3 is attached. In the drawing, an oil diffusion pump 5 is connected to the lower portion of the vacuum duct 3 via a gate valve 4, and a rotary pump 6 is connected downstream of the oil diffusion pump 5.

On the other hand, a lid 7, to which a refrigerator, in this case, a helium refrigerator 8 is attached, is attached to the upper part of the vacuum duct 3. The helium refrigerator 8 has a cold station 9 arranged in the vacuum duct 3 penetrating the lid 7, and a cold plate 10 of a cylindrical shape is attached to the cold station 9 in this case. The cooling plate 10 is arranged corresponding to the exhaust port 2.

The helium refrigerator 8 is connected to the compressor 11 via pipes 12 and 13 that circulate helium gas that is a refrigerant. A power source 15 is connected to the compressor 11 via an inverter 14. A controller 17 is connected to the inverter 14, and
The heat loader 16 attached to the cold station 9 is connected to the controller 17.

In this case, the heat loader 16 is of a temperature element built-in type, and is adapted to input the temperature of the cold station 9 to the controller 17. The controller 17 inputs the temperature information from the heat loader 16 and compares it with the control value.If the input value is lower than the control value, the heat loader 16 issues an instruction to output the heat load, In order to minimize the heat load output of the loader 16, the inverter 12 is controlled to control the amount of cold generation in the helium refrigerator 8. Further, when the temperature input value from the heat loader 16 is higher than the control value, the controller 17 does not output the heat load from the heat loader 16, and the inverter
14 is controlled to increase the amount of cold generation in the helium refrigerator 8.

With the vacuum exhaust device configured in this way, the inverter
By controlling the compressor 14 and operating the compressor 11 to supply and circulate the helium gas to the helium refrigerator 8, the helium refrigerator 8 generates cold without replenishing the helium gas as the refrigerant, and the cold station 9 is operated. Cooling. Cold plate of cold station 9 cooled
The cooling plate 10 is transmitted to the cooling plate 10 and cooled. In this case, since the refrigerator uses a helium refrigerator, the cooling plate 10 is about 20K.
It can be cooled down to.

Accordingly, when the gate valve 4 is opened and the exhaust chamber 1 is vacuum-exhausted by the rotary pump 6 and the oil diffusion pump 5, the gas in the exhaust chamber 1 is exhausted from the exhaust port through the vacuum duct 3 to the oil diffusion pump. 5, The rotary pump 6 is sequentially sucked and exhausted. At this time, the gas entering the vacuum duct 3 from the exhaust port 2 hits the cooling plate 10 provided in the vacuum duct 3 corresponding to the exhaust port 2, and the temperature of the gas is higher than that of the cooling plate 10. The gas having the boiling point of the temperature is cooled by the cooling plate 10, condensed or solidified and adsorbed on the cooling plate 10, and the remaining gas except the gas adsorbed and removed on the cooling plate 10 flows to the oil diffusion pump 5 side. Is exhausted.

For example, if the temperature of the cooling plate 10 is cooled to about 150K, water, gas such as iodine can be trapped by the cooling plate 10, and if the cooling plate 10 is cooled to about 100K, ammonia can be further trapped. Carbon dioxide can be further trapped by cooling to about 85K, xenon can be trapped by cooling the cooling plate 10 to about 55K, and methane can be further trapped by cooling the cooling plate 10 to about 35K. If cooled to about 30K, more argon can be trapped.

In this way, by compressing and circulating the helium gas in the compressor 11, it is possible to continuously obtain cold from the helium refrigerator 8 without replenishing the helium gas, and to constantly cool the cooling plate 10.
Can be cooled. Further, the controller 17 controls the inverter 14 to control the amount of helium gas supplied to the compressor 11 and the amount of cold generation of the helium refrigerator 8 to select and trap the gas species.

Vacuum pumping equipment (vacuum processing equipment) with such characteristics
Will be described, for example, when it is used in a sputtering apparatus which is a semiconductor manufacturing apparatus. First, set the temperature of the cooling plate 10 to 30K.
After cooling to the following and starting the vacuum exhaust, all the above-mentioned gases are trapped immediately after the start of the vacuum exhaust, and the inside of the exhausted chamber (vacuum processing chamber) 1 is exhausted to a high vacuum within a short time. After evacuation to a predetermined high vacuum area, the gate valve 4
And the temperature of the cooling plate 10 is raised to about 32K, and only the high boiling point gas other than the argon gas is trapped. The temperature rise of the cooling plate 10 at this time is controlled by the controller 17 to output the heat load from the heat loader 16, and the inverter 14 is controlled to slightly reduce the supply amount of the helium gas from the compressor 11 to cool the cooling plate 10. Helium refrigerator 8 when operating at a temperature of 10 at 32K
Then, the cooling plate 10 is quickly heated.

Next, argon gas is supplied into the exhaust chamber 1 by a device (not shown), and in this state, the pressure inside the exhaust chamber 1 is adjusted to, for example, 10 ⁻³ to 10 ⁻⁴ mmHg, and the inside of the exhaust chamber 1 is adjusted. Under the sputtering conditions. At this time, except for argon in the exhaust chamber 1,
That is, the partial pressure of the high boiling point gas having a temperature of 30 K or higher needs to be suppressed as low as possible, and this can be done by controlling the temperature of the cooling plate 10 to about 32 K. Further, by squeezing the gate valve 4 in this state, the consumption of argon gas can be reduced.

As described above, according to the present embodiment, since the cooling plate 10 is cooled by the helium refrigerator 8, it is not necessary to replenish a cryogen such as liquid nitrogen for cooling the trap as in the conventional case.
The cooling plate can be constantly kept at a low temperature to maintain the exhaust performance and prevent the trapped gas from rising.

Further, the controller 17 controls the inverter 14 to control the compressor 11
Since the amount of cold generation of the helium refrigerator 8 can be controlled by adjusting the supply amount of the refrigerant, the temperature of the cooling plate 10 can be controlled to an arbitrary value, and the gas to be trapped can be selected.

Further, since the controller 17 controls the heat loader 16 to output the heat load to heat the cooling plate 10, it is possible to quickly control the temperature of the cooling plate 10 and, similarly to the above, to trap the gas to be trapped. The effect is that you can choose. Further, by performing the control in combination with the control of the amount of cold generation, it is possible to perform efficient control.

Furthermore, when applied to a sputtering device, etc., the conventional technology was able to cool the temperature of the cooling plate to only about 77K and could not trap the gas having a boiling point temperature of 77K or less, so the vacuum exhaust was started. It took a long time to exhaust the exhausted chamber to a high vacuum region, but according to the present embodiment, the cooling plate 10 can be cooled to about 30 K to adsorb and remove all gas species, so that a high vacuum can be obtained. There is an effect that it is possible to shorten the time for exhausting to the region.

In this embodiment, the cooling plate 10 has a cylindrical shape and the exhaust port 2
However, it may be arranged as shown in FIGS. 2 and 3.

FIG. 2 shows that a cooling plate 10a having a plurality of V-shaped cross-section plates provided circumferentially is arranged in a vacuum duct 3a provided so as to face the exhaust port 2, and the cooling plate 10a is connected to the helium refrigerator 8. It is attached to the cold station 9 so that of the gases exhausted from the exhaust port 2, the gas having a boiling point higher than the temperature of the cooling plate 10a is adsorbed and removed by the cooling plate 10a. The operation of the helium refrigerator 8 is the same as that of the one embodiment.

In FIG. 3, the vacuum throttle valve 19 is connected through the vacuum duct 3b which is continuous with the exhaust port 2 and changes the direction of the exhaust path, and further the oil diffusion pump 5 is connected. In this case, a cooling plate 10b similar to that shown in FIG. 2 is arranged on the upstream side of the vacuum throttle valve 19, the cooling plate 10b is attached to the cold station 9 of the helium refrigerator 8, and the gas exhausted from the exhaust port 2 is removed. Of which, cooling plate
A gas having a boiling point higher than the temperature of 10b is adsorbed and removed by the cooling plate 10b. Further, the valve 18 is arranged on the downstream side of the vacuum throttle valve 19 to adjust the exhaust flow rate of the remaining gas adsorbed and removed by the cooling plate 10b.

Further, in the present embodiment, a combination of the oil diffusion pump 5 and the rotary pump 6 is used as the vacuum exhaust pump, but another vacuum pump such as a turbo molecular pump is used instead of the oil diffusion pump. Is also good.

Further, although the cooling plate is used to trap the exhaust gas in this embodiment, the adsorbent is attached to the cooling plate to cool the adsorbent, and the exhaust gas is adsorbed and removed by the cooled adsorbent. You may do it.

〔The invention's effect〕

According to the present invention, the cooling plate can be always kept at a low temperature to maintain the exhaust performance, and the trapped gas can be prevented from rising. That is, the amount of exhaust gas may be adjusted by controlling the gate valve so that the vacuum pump can exhaust the argon gas that has not been adsorbed and removed by the cooling plate. For this reason, the amount of argon gas supplied to the vacuum processing chamber can be reduced, which has the effect of reducing the amount of argon gas consumed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a vacuum exhaust device which is an embodiment of the present invention, and FIGS. 2 and 3 are partial cross-sectional views showing another embodiment of the present invention. 1 ... Exhaust chamber, 3, 3a ... Vacuum duct, 5 ... Oil diffusion pump, 6 ... Rotary pump, 8 ... Helium refrigerator,
10,10a, 10b …… Cooling plate, 19 …… Vacuum throttle valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadashi Takada 794 Azuma Higashitoyo, Shimomatsu City, Yamaguchi Prefecture Inside the Kasado Plant, Hitachi Ltd. (56) References JP-A-55-33059 (JP, A)

Claims (1)

[Claims] 1. A temperature controllable cooling plate which is provided in the middle of an exhaust pipe connecting a vacuum processing chamber to which argon gas is supplied as a processing gas and a vacuum pump and which is cooled by a refrigerator.
It is provided with a gate valve provided between the exhaust pipe and the vacuum pump for adjusting the exhaust flow rate of the vacuum processing chamber, and after evacuation to a predetermined high vacuum region, the temperature of the cooling plate is controlled to about 32K by the refrigerator, A method for operating a vacuum processing apparatus, comprising: adsorbing and removing a gas having a boiling point higher than the temperature of a cooling plate by the cooling plate, and adjusting the exhaust amount of the remaining gas by controlling the opening of a gate valve.