JPH0511223B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cryopump that can be used in a vacuum device that introduces a large amount of gas, such as a sputter device.

[Conventional technology]

An example of this type of cryopump is shown in FIG. 2 of the accompanying drawings, and in the illustrated device, the condensing surface is comprised of a baffle A, a cryopanel B, and a shield c. The buffer A and the shield c are thermally connected to the stage part of the first stage cylinder D of the refrigerator, and the cryopanel B is thermally connected to the stage part of the second stage cylinder E, and they are 130K or less and 20K, respectively. It is cooled below.

In the conventional cryopump as described above, the buffer A and shield C, which are thermally connected to the stage of the first stage cylinder D of the refrigerator, are 130K.
Water, carbon dioxide, etc. are condensed and exhausted. The cryopanel B, which is thermally connected to the stage of the two-stage cylinder E of the refrigerator, is cooled to below 20K and exhausts argon, nitrogen, oxygen, carbon monoxide, etc. In addition, a sorbent is attached to the back side of the cryopanel B, and it is configured to be cooled to below 20K to adsorb and exhaust hydrogen, helium, and neon.

[Problem that the invention seeks to solve]

By the way, in conventional cryopumps,
Argon, nitrogen, etc. condensed on the cryopanel may fall due to vibration or large radiant heat input.
Falling argon and other deposits fall onto the shield where the temperature is higher and are re-evaporated. This causes pressure instability and pressure rise. This is extremely inconvenient when using the device.

Therefore, this invention solves the above-mentioned problems with conventional cryopumps and makes it possible to prevent deposits such as argon from falling onto the same temperature surface, thereby preventing pressure instability and pressure rise. The purpose is to provide cryopumps.

[Means for Solving the Problems] In order to achieve the above object, the cryopump according to the present invention has a cryopump that receives deposits such as argon that condense on the cryopanel, flake off, and fall. The feature is that this saucer is placed at the bottom and is kept at approximately the same temperature as the cryopanel.

According to another feature of the present invention, if argon or the like condenses on the underside or side surface of the saucer itself, the phenomenon of flaking and falling is likely to occur, so in order to prevent argon gas from entering the underside of the saucer as much as possible, An L-shaped ring that is thermally connected to the shield and cooled to a temperature similar to that of the shield is provided between the peripheral edge of the saucer and the shield.

The gap between the saucer and the L-shaped ring is made as small as possible,
Avoid condensation of argon on the edges or back side of the ring. Further, the L-shaped ring can preferably be installed at a distance sufficient to prevent argon or the like falling from the cryopanel from falling onto the L-shaped ring.

[Effect]

In the cryopump of this invention, the saucer provided at the bottom of the cryopanel is cooled to a temperature similar to that of the cryopanel, for example, 20K or less, so even if deposits such as argon fall, it will remain cooled to the same temperature of 20K or less. Because the liquid falls into the saucer, instability in the pressure and rise in pressure can be suppressed as much as possible.

Further, the L-shaped ring provided between the saucer and the shield acts to prevent argon and the like from condensing on the lower surface and side surfaces of the saucer itself.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIG. 1 of the accompanying drawings.

FIG. 1 shows an embodiment of the present invention. Reference numeral 1 denotes a pump case, and inside this pump case there are provided a buttful 2, a cryopanel 3, and a shield 4, which constitute a condensing surface. 4 is thermally connected to the stage of the single stage cylinder 5 of the refrigerator and cooled to below 130k, water,
It condenses and exhausts carbon dioxide, etc. The cryopanel 3 is thermally connected to the stage of a two-stage cylinder 6 of a refrigerator, and is cooled to below 20K, and is designed to exhaust argon, nitrogen, oxygen, carbon monoxide, etc. In addition, a sorbent is attached to the back side of the cryopanel 3 as usual, and when the cryopanel 3 is cooled to below 20K, hydrogen, helium, and neon are absorbed and removed.

In addition, the lower part of the cryopanel 3 is thermally connected to the stage of the two-stage cylinder 6 of the refrigerator.
A saucer 7 cooled to 20K or less is provided, and even if argon or the like falls, the saucer 7 remains cooled to 20K or less, so pressure instability and pressure rise can be suppressed as much as possible. Furthermore, if argon condenses on the underside or side surface of the saucer 7 itself, it may fall onto the shield 4 due to vibrations, etc., causing pressure instability or pressure rise. Like shield 4 and saucer 7
An L-shaped ring 8 is provided between the shield 4 and the peripheral edge thereof, and this L-shaped ring 8 is thermally connected to the shield 4.
And it is cooled below 130k. saucer 7 and L
The gap between the mold ring 8 and the mold ring 8 is made as small as possible to prevent argon, etc. from condensing on the edge or back surface of the ring.The L-shaped ring 8 also prevents argon, etc., falling from the cryopanel from condensing on the L-shaped ring 8. It is positioned far enough away that it will not fall.

In addition, in FIG. 1, 9 is a hydrogen vapor pressure thermometer,
10 is a chromel-alumel thermocouple thermometer.

〔Effect of the invention〕

As explained above, the cryopump according to the present invention has a saucer maintained at the same temperature as the cryopanel at the bottom.
Falling deposits such as argon do not evaporate again, and pressure instability and rise no longer occur. As a result, the degree of vacuum recovers quickly after sputtering or other work is completed, and unstable pressure phenomena do not occur, resulting in improved work efficiency and a longer regeneration cycle of the cryopump.

[Brief explanation of the drawing]

FIG. 1 shows a sectional view showing an embodiment of the invention. FIG. 2 shows a cross-sectional view of a conventional cryopump. In the diagram, 1: pump case, 2: full, 3:
Cryopanel, 4: shield, 5: single-stage cylinder, 6: two-stage cylinder, 7: saucer, 8: L-shaped ring, 9: hydrogen vapor pressure thermometer, 10: chromel-alumel thermocouple thermometer.

Claims (1)

[Claims] 1. An extremely low-temperature tray is provided at the bottom of the cryopanel to catch deposits such as argon that condense on the cryopanel, flake off, and fall, and this tray is kept at approximately the same temperature as the cryopanel. A cryopump featuring: 2. A cryogenic tray is provided at the bottom of the cryopanel to catch deposits such as argon that condense on the cryopanel, flake off, and fall, and this tray is kept at approximately the same temperature as the cryopanel, and is kept at a temperature similar to that of the shield. A cryopump characterized in that an L-shaped ring that is cooled by the temperature is provided between the peripheral edge of the saucer and the shield.