JPH06129352A - Crio-pump safety device - Google Patents

Abstract

PURPOSE:To prevent explosion accident by securing a path for releasing abnormal pressure generated in an enclosure fitted with crio-panel even in case a relief valve goes in clogs in its filter to check biting-in of refuses. CONSTITUTION:A filter 7 is composed of plate-shaped split pieces 7a, 7b in the form of a semi-circular disc to be fixed by spot welding partially to the inside of a relief passage 9, and the adjoining edges of these split pieces 7a, 7b are overlapped so that the pressure acting on the filter 7 at its clogging generates a deformation to produce a crevice 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryopump which freezes and adsorbs gas molecules from the processing chamber side such as a spatter to a cryopanel cooled to an extremely low temperature of several tens of K in absolute temperature and draws a vacuum inside the processing chamber. Safety device.

[0002]

2. Description of the Related Art Conventionally, a cryopump of this type has been disclosed in Japanese Patent Laid-Open No. 252982/1990, and as shown in FIG. 8, an absolute temperature of about 50 to 70K is stored inside an enclosure E having a flange J at its opening. A gas-expansion refrigerator D having a first heat stage F for cooling and a second heat stage S for cooling to about 15 to 20K is provided, and a heat shield panel G having a baffle B at the end is attached to the first heat stage F. The cryopanel P holding the activated carbon C on the back side is attached to the second heat stage S. Thus, during processing such as sputtering, gas molecules such as argon on the processing chamber side are frozen and adsorbed on the cryopanel P, and the processing chamber side is evacuated. Also, during the regeneration process, the opening of the enclosure E is shut off from the process chamber side via the valve, the operation of the refrigerator D is stopped, the gas molecules accumulated on the cryopanel P are vaporized, and a pump-out (not shown) is performed. It is designed to be discharged from the port by a roughing pump or the like.

When an abnormal situation such as a power failure occurs mainly during the above-described regeneration process and the exhaust cannot be performed normally, the internal pressure of the enclosure E abnormally rises, which causes a risk of explosion. The enclosure E is connected with a relief valve L for releasing an abnormal pressure rise to the outside, and normally, when the relief valve L is returned to the operating state, fine powder of the work or fragments of the activated carbon C caused by the spatter on the valve seat etc. A filter K is provided in the front stage of the relief valve L so that there is no such biting.

[0004]

However, in the case where the filter K is interposed in the preceding stage of the relief valve L as described above,
When the filter K itself is clogged with fine particles of the work, the relief passage leading to the relief valve L is blocked, and the path for releasing an abnormal pressure rise is cut off, which causes a problem that it does not function as a safety device. is there.

The main object of the present invention is to secure a path for releasing an abnormal pressure generated in the enclosure even when the filter is clogged, and to prevent an explosion accident. The point is to provide a device.

[0006]

In order to achieve the above main purpose, as shown in FIGS. 1 to 4, firstly, a relief valve that opens due to an abnormal pressure rise in an enclosure 5 that houses a cryopanel 4 therein. A safety device for a cryopump, comprising a filter 7 provided in front of the relief valve 6, and the filter 7 is deformed by pressure applied to the filter 7 when the filter 7 is clogged to open the mouth. A rift 8 was provided for opening.

Secondly, in order to make the interposed portion of the filter 7 compact, as shown in FIGS. 1 to 3, by the first means, the filter 7 connects the enclosure 5 and the relief valve 6 to each other. The relief passage 9 is made up of a plurality of plate-shaped divided pieces 7a and 7b whose outer peripheral portions are fixed, and adjacent sides of the divided pieces 7a and 7b are overlapped with each other.

Thirdly, in order to facilitate the replacement work of the filter 7 and the maintenance work at the time of regeneration, in addition to the above-mentioned first or second means, a mounting portion 57 is provided on the wall portion of the enclosure 5, The relief valve 6 is provided inside the mounting portion 57.
A passage block 91 having a relief passage 9 communicating with the above is detachably attached to hold the filter 7 inside the passage block 91.

Fourthly, in order to secure a large passage area of the filter 7 and reduce the frequency of clogging of the filter 7 by the first means, as shown in FIGS. The filter 7 has a tubular shape facing the internal space of the enclosure 5, and a support body 7c that constitutes the tubular frame, and a plurality of support bodies 7c that are fixed to the support body 7c and that form the tubular outer shape. Comprised of tubular split pieces 7d, 7e,
Adjacent sides of each of the divided pieces 7d and 7e are overlapped with each other.

Fifthly, in order to enable the filter 7 to be reused and to make it economical by each of the above-mentioned first to fourth means, the filter 7 removes the pressure exerted when the filter 7 is clogged. It is formed of a material having an elastic restoring force that closes the mouth of the slit 8.

[0011]

By the first means, when the filter 7 is clogged, the crevice 8 opens its mouth, and a pressure relief path connecting the inside of the enclosure 5 and the relief valve 6 is secured, so that the explosion of the enclosure 5 occurs. Can be avoided in advance.

Before the filter 7 is clogged by the second means, as shown in FIG.
Adjacent sides of a and 7b overlap each other, dust such as fine powder of the work can be removed in the preceding stage of the relief valve 6, and after the filter 7 is clogged, as shown in FIG. At the overlapping portion of 7a and 7b, the crevice 8 opens a mouth, and a pressure relief path can be secured. In this way, the filter 7 is composed of a plurality of plate-shaped divided pieces 7a and 7b, and the filter 7 itself is formed in a plate shape to be thin, so that the interposed portion of the filter 7 can be made compact.

By removing the passage block 91 from the mounting portion 57 by the above-mentioned third means, the filter 7 can be easily replaced and regenerated, and the maintenance work of the filter 7 can also be easily carried out.

By the fourth means, since the filter 7 is formed into a cylindrical shape which faces the inner space of the enclosure 5, a large passage area of the filter 7 can be secured and the frequency of clogging in the filter 7 can be reduced. Yes, but at the time of clogging, as shown in FIG.
At the overlapping portion of d and 7e, the crevice 8 opens its mouth and its safety can be secured.

By the fifth means, the original shape can be restored by performing the reproduction for eliminating the clogging condition generated in the filter 7, so that the filter 7 can be reused and the economy can be improved accordingly. Can be achieved.

[0016]

EXAMPLE A cryopump shown in FIG.
~ 70K First Heat Stage 1 and 15 ~ 2
The second heat stage 2 of about 0K is provided, and the refrigerator main body 10 for expanding the helium gas supplied and discharged through the high pressure connection port 11 and the low pressure connection port 12 is provided. The heat shield panel 3 is provided inside the enclosure 5 having the small-diameter tubular portion 52, has a bottomed tubular heat shield panel 3 having a baffle 31 at the end thereof, and is attached to the second heat stage 2. The reverse bottomed tubular cryopanel 4 holding the activated carbon 41 is attached to the back side.

Thus, during processing such as sputtering in the processing chamber connected to the opening flange 50 side of the enclosure 5,
Gas molecules such as argon are frozen and adsorbed on the cryopanel 4, and the processing chamber side is evacuated. During regeneration processing, the opening flange 50 side of the enclosure 5 is blocked from the processing chamber side by the main valve. Then, the operation of the refrigerator 10 is stopped and the heat stages 1 and 2 are heated to vaporize the gas molecules accumulated on the cryopanel 4, and
Nitrogen gas is also injected from the purge port 53,
The water is discharged from the pump out port 54 to the outside via a roughing pump or the like. In FIG. 4, 55 is a vapor pressure thermometer.

The small-diameter cylindrical portion 52 of the enclosure 5
Is provided with a safety device 56 that mainly copes with an abnormal situation at the time of regeneration processing. As shown in FIG. 1, the safety device 56, when the abnormal pressure in the enclosure 5 rises,
A plurality of communication holes 6 are provided in the valve seat block 62, which move against the biasing body 61 formed of a coil spring.
A relief valve 6 for opening the valve 3 to the outside and a filter 7 made of a mesh body made of copper, aluminum, or the like, which is provided in the preceding stage, are provided.

With the above construction, the filter 7 is provided with the crevice 8 which is deformed by the pressure applied to the filter 7 when the filter 7 is clogged to open the mouth. Specifically, FIG. 2 and FIG. As also clearly shown, the filter 7 is connected to the relief passage 9 connecting the enclosure 5 and the relief valve 6.
It is formed by plate-like divided pieces 7a, 7b consisting of two semi-circular plates for fixing the outer peripheral portion inside thereof.
The adjacent sides of b are overlapped with each other.

Further, with the above construction, the flange-shaped mounting portion 57 is provided on the wall portion of the small-diameter cylindrical portion 52 of the enclosure 5.
The passage block 91 having the relief passage 9 provided therein, the valve seat block 62 and the lower flange 64 on the outer side are detachably attached to the attachment portion 57 via attachment bolts 65. In this way, the filter 7 is held inside the passage block 91 which can be freely attached and detached, through the spot welding portion 71 which is partially formed on the outer peripheral portion thereof.

In FIG. 1, 58, 92 and 66 are O-rings for sealing.

By the way, in the above, the filter 7 is formed in a plate shape, and this is used as the small-diameter cylindrical portion 5 of the enclosure 5.
It is held by a passage block 91 which is detachably attached to the side portion of the enclosure 2. However, as shown in FIG. 5, the filter 7 has a tubular shape facing the internal space of the large diameter portion 51 of the enclosure 5, and FIG. As shown in FIG. 7 and FIG. 7, the tubular frame is formed, and the relief passage pipe 93 is provided via the lower claw portion 72.
The support 7c to be engaged with the inlet recess 94 of the, and fixed to the support 7c via a partial spot weld 73,
A plurality of tubular divided pieces 7d and 7e that form the tubular outer shape
The divided sides 7d and 7e may be formed by superposing adjacent sides of each other. In this case, a large passage area of the filter 7 can be ensured and the clogging itself of the filter 7 itself can be ensured. The frequency of occurrence of can be reduced.

Further, in each of the above embodiments, the filter 7 is formed of copper, aluminum or the like, and is made of spring steel or the like having an elastic restoring force that closes the mouth of the crevice 8 when the pressure applied when the filter 7 is clogged is removed. The filter 7 may be made of the same material, and in this case, the filter 7 can be recycled.

[0024]

According to the invention described in claim 1, even if the filter 7 is clogged, a pressure relief path connecting the inside of the enclosure 5 and the relief valve 6 can be secured, and an explosion accident of the enclosure 5 occurs. Can be avoided in advance.

According to the second aspect of the invention, since the filter 7 is composed of the plurality of plate-shaped divided pieces 7a and 7b, the filter 7 can be made thin, and the interposed portion of the filter 7 can be made compact.

According to the third aspect of the present invention, the filter 7 can be easily replaced or regenerated by removing the passage block 91, and maintenance work can be easily performed.

According to the fourth aspect of the present invention, the tubular filter 7 makes it possible to reduce the frequency of occurrence of clogging of the filter 7, and at the same time, ensure safety at the time of clogging.

According to the invention described in claim 5, the filter 7
Can be recycled and can be made economical.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a cryopump safety device according to the present invention.

FIG. 2 is a perspective view of an essential part of a filter portion showing a normal state in the first embodiment.

FIG. 3 is a perspective view of a main part of a filter portion showing a state at the time of clogging in the first embodiment.

FIG. 4 is a perspective view of the entire cryopump including the safety device according to the first embodiment.

FIG. 5 is a perspective view of the entire cryopump including the safety device according to the second embodiment.

FIG. 6 is a perspective view of a main part of a filter portion showing a normal state in the second embodiment.

FIG. 7 is a perspective view of an essential part of a filter portion showing a state at the time of clogging in the second embodiment.

FIG. 8 is a cross-sectional view showing a conventional safety device for a cryopump.

[Explanation of symbols]

4; Cryopanel, 5; Enclosure, 57; Mounting part, 6; Relief valve, 7; Filter, 7a, 7b; Plate-shaped divided piece, 7c; Support, 7d, 7e; Cylindrical divided piece, 8;
Rift, 9; relief passage, 91; passage block

Claims (5)

[Claims] 1. A safety device for a cryopump, comprising: a relief valve (6) that opens when an abnormal pressure rises in an enclosure (5) containing a cryopanel (4), and a filter (7) in front of the relief valve (6). 7. A safety device for a cryopump, characterized in that a rift 8 is provided in 7 to deform and open the mouth by the pressure applied to the filter 7 when the filter 7 is clogged. 2. A filter 7 comprises a plurality of plate-shaped divided pieces 7a, 7b for fixing the outer peripheral portion inside a relief passage 9 connecting the enclosure 5 and the relief valve 6, and each of these divided pieces 7a, 7b. The cryopump safety device according to claim 1, wherein adjacent sides are overlapped with each other. 3. A mounting portion 57 is provided on a wall portion of the enclosure 5, and a passage block 91 having a relief passage 9 communicating with the relief valve 6 therein is detachably attached to the mounting portion 57 so that the passage block 91 can be attached. The cryopump safety device according to claim 1 or 2, further comprising a filter 7 held therein. 4. A filter 7 has a tubular shape facing the internal space of the enclosure 5 and is fixed to the supporting body 7c which constitutes the tubular frame and the supporting body 7c. It is composed of a plurality of cylindrical divided pieces 7d and 7e,
2. The cryopump safety device according to claim 1, wherein adjacent sides of each of the divided pieces 7d and 7e are overlapped with each other. 5. The filter 7 according to claim 1, wherein the filter 7 is made of a material having an elastic restoring force that closes the mouth of the crevice 8 when the pressure exerted when the filter 7 is clogged is removed. Cryopump safety device.