JP2943489B2 - Cold trap for evacuation system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold trap which condenses and exhausts moisture interposed between a vacuum chamber and a vacuum exhaust device.

[0002]

2. Description of the Related Art Heretofore, a cold trap using a helium refrigerator has been known, and this cold trap is used by interposing it in an exhaust path between a vacuum chamber and an air exhaust device. This cold trap condenses and exhausts the moisture in the vacuum chamber on a surface (cryo surface) cooled to an extremely low temperature. By this moisture exhaustion, the vacuum chamber can be efficiently evacuated by the vacuum evacuation device, and the moisture can be removed. A clean vacuum with few impurities can be obtained.

As shown in FIG. 12, a conventionally known cold trap comprises an exhaust port B communicating with a vacuum chamber A and an exhaust port communicating with a vacuum exhaust device C comprising, for example, a cryopump. D with trap body E
In addition, a cold panel K is internally provided while a heat stage H of a helium refrigerator F is inserted, and the cold panel K is thermally connected to the heat stage H.

[0004]

The evacuation of water by a cold trap is performed by cooling the cold panel K to an extremely low temperature and condensing the water in the cold panel K. In the trap, the cold panel K is connected to the heat stage H of the refrigerator F.
The temperature of the cold panel K is determined by taking into consideration the size and heat load of the panel K, the type of process gas, its partial pressure and moisture pressure, and The refrigeration capacity is set.

However, in the above configuration, if the temperature of the cold panel K is too low, the process gas such as argon gas used in the vacuum chamber A is condensed, and the sample gas is re-discharged from the cold panel when the pressure drops thereafter. This causes a problem that pressure control cannot be performed.

SUMMARY OF THE INVENTION It is an object of the present invention to use a refrigerator having a sufficient refrigerating capacity capable of effectively exhausting moisture from a cold panel and maintaining an optimum temperature at which process gas does not condense. Another object of the present invention is to provide a cold trap capable of increasing the overhaul time by increasing the capacity reduction allowance.

Another object of the present invention is to provide a cold trap which can be applied not only to exhaustion of moisture but also to exhaustion of other gases and has improved versatility.

[0008]

According to a first aspect of the present invention, there is provided a trap body having an exhaust inlet connected to a vacuum chamber and an exhaust outlet connected to a vacuum exhaust device.
And the inlet portion 11 of the trap body 10 is provided.
Stage 29 of the refrigerator 13 between the
And a cold panel 14, which is thermally connected to the heat stage 29, and an electric heater 15 is attached to the cold panel 14, while the cold panel 14
And the cylindrical portion 14a and a part of the cylindrical portion 14a are flattened.
And the surface of the flat portion 14b.
The flat part of the heat stage 29 and the electric heater
According to the second aspect of the present invention, the trap body 10 has a heat absorbing portion 35a which is exposed to the outside of the trap body 10 and absorbs heat from the outside air at one end, and at the other end. Further, a heat conductor 35 having a heat radiating portion 35b which protrudes into the inside of the trap body 10 and comes into contact with the cold panel 14 is provided.

In this case, the heat absorbing portion 3 of the heat conductor 35
5a and the heat radiating portion 35b are separately formed, and the heat absorbing portion 3b is formed.
5a includes a heat transfer section 37 which protrudes into the trap body 10 and faces the heat radiating section 35b.
Is a heat conducting portion which is in contact with and supported by the cold panel 14, and which is in contact between the heat radiating portion 35b and the heat transfer portion 37 by thermal deformation when the cold panel 14 is cooled to a predetermined temperature or lower. Preferably, 40 are provided.

A third invention is directed to the heat stage 2
Between the cold panel 9 and the cold panel 14, a spacer 41 made of a material having a low heat transfer coefficient in a low temperature range below a predetermined temperature is interposed.

[0011]

In any case, the temperature of the cold panel 14 can be controlled to a predetermined temperature by raising the temperature of the cold stage 14 to the temperature of the heat stage 29. Therefore, the temperature of the cold panel 14 is optimal for exhausting moisture. Thus, the temperature can be maintained within a suitable temperature range, and therefore, moisture can be effectively exhausted and the process gas can be prevented from being condensed. In addition, a refrigerator having a sufficient refrigerating capacity can be used. Therefore, even if a seal ring provided on a slack piston or a displacer of the refrigerator is worn due to use and the capacity is reduced, the capacity reduction allowable amount is allowed. Therefore, overhaul time such as replacement of the seal ring can be extended.

Further, according to the first aspect of the invention using the heater 15 , heat is applied to the surface of the flat portion of the cold panel 14.
Since the flat part of the cottage 29 is attached, heat transfer is good,
The installation is easy and reliable, and the cold panel 1
Attach the flat part of the electric heater 15 to the back of the flat part of No. 4.
Therefore, the heat transfer is good and the installation is easy and reliable.
You. Moreover, the temperature of the electric heater 15 can be arbitrarily adjusted,
In addition, since the adjustment width can be increased, a refrigerator having a larger refrigerating capacity can be used. Therefore, the capacity reduction allowance can be further increased, and the cool down time can be shortened. The temperature can be arbitrarily adjusted, and the temperature of the cold panel 14 can be raised to room temperature in a short time.
In addition, the regeneration time for removing the water condensed in 4 can be shortened, and the refrigerating capacity of the refrigerator can be increased, and the temperature of the heat stage 29 can be lowered.
By controlling the temperature by the heater 15, not only moisture,
It can also be used to exhaust other gases.

In the second invention using the heat conductor 35, since the outside air temperature is used without specially using a heat source as in the first invention, the structure can be simplified and energy consumption can be reduced. The temperature of the cold panel 14 can be arbitrarily adjusted by selecting the cross-sectional size of the heat conductor 35.

Further, when the heat absorbing portion 35a and the heat radiating portion 35b of the heat conducting member 35 are divided and a heat conducting portion 41 is brought into contact by thermal deformation when the cold panel 14 is cooled below a predetermined temperature. Means that the cooldown time can be shortened while the effect of the second invention is obtained.

In the case where a spacer 41 made of a material whose heat transfer coefficient is reduced in a low temperature range below a predetermined temperature is interposed between the heat stage 29 and the cold panel 14,
The structure can be simplified while the effect of shortening the cool down time is obtained.

[0016]

FIG. 11 shows a cryopump 3 applied to a vacuum chamber 2 used in a vacuum chamber of a semiconductor manufacturing apparatus, which is connected to an argon gas cylinder 1 and sputters a semiconductor wafer. A cold trap 5 according to the present invention, together with a conductance valve unit 4 for adjusting the partial pressure of argon gas, is interposed in a vacuum pumping path of a connected vacuum pumping device so as to discharge moisture in the vacuum chamber 2. In addition, the vacuum trap 2 is evacuated by the cold trap 5 to evacuate the water that occupies most of the impurities in the vacuum chamber 2, so that the vacuum chamber 2 can be efficiently and cleanly evacuated.

Thus, the cold trap 5 according to the present invention is, as shown in FIGS.
And a trap body 10 having an exhaust inlet 11 communicating with the cryopump 3 of the vacuum evacuation apparatus, and a trap body 10 provided between the inlet 11 and the outlet 12 in the trap body 10. , A heat stage 29 of the refrigerator 13 and a cold panel 14 thermally connected to the heat stage 29.
In the first embodiment, an electric heater 15 is mounted on the cold panel 14.

The trap body 10 has a cylindrical shape. The inlet 11 and the outlet 12 have a mounting flange 16 connected to a flange 7 of a vacuum chamber 6 forming the vacuum chamber 2 and a conductance of the vacuum exhaust device. Valve unit 4
Is provided with a mounting flange 17 which is connected to the flange 9 of the valve body 8 at the center.
A mounting section 20 for a power cord 19 to be connected to the heater 15 is provided on the opposite side of the mounting cylindrical section 18.

The refrigerator 13 is a helium refrigerator. As shown in FIG. 3, a main housing 23 having a valve motor 21 and a switching valve 22, a slack piston 24 and a displacer 25 are sealed. Ring 2
And a cylinder 27 slidably mounted through the cylinder 6. The switching valve 22 is operated by driving the valve motor 21, and high-pressure helium gas is supplied to the cylinder 27.
Or by discharging the low-pressure helium gas expanded in the expansion space 28 provided at the distal end side of the displacer 25 to keep the heat stage 29 adjacent to the expansion space 28 at an extremely low temperature. It is.

1 and 11, reference numeral 30 denotes a compressor unit provided with a helium gas compressor. The compressor unit 30 connects a high-pressure helium gas pipe 31 to a high-pressure connection port 32 provided in the main body housing 23 and a low-pressure helium gas pipe 31. Helium gas pipe 3
3 is connected to the low pressure connection port 34.

In the above structure, the cold panel 14 is cooled to an extremely low temperature, and the moisture is condensed on the cryogenic surface cooled at an extremely low temperature. In order to effectively perform the above, for example, in order to keep the vapor pressure of water at 10 ^-10 Torr or less, the temperature of the cold panel 14 needs to be 130 k or less at which the partial pressure of water vapor becomes the vapor pressure.

On the other hand, when the vacuum chamber 2 is set to an argon gas atmosphere, for example, when the partial pressure of the argon gas is 10 ² Torr or less, the argon gas molecules are condensed and exhausted at 80 K or less. Control becomes difficult. Therefore, in order to suppress the evacuation of the argon gas and make the evacuation of the moisture effective, it is necessary to maintain the temperature of the cold panel 14 at 80 to 130K.

In the first embodiment shown in FIGS. 1 to 3, since the electric heater 15 is provided on the cold panel, the refrigerating capacity of the refrigerator 13 depends on the heat stage 29, The ability to cool to a cryogenic temperature lower than the above-mentioned temperature range of the cold panel 14, for example, a cryogenic temperature of 40K can be achieved. Note that FIG. 1 to FIG.
As described above, the cold panel 14 includes a cylindrical portion 14a,
A flat portion 14b is obtained by flattening a part of the cylindrical portion 14a.
A heat stay is formed on the surface of the flat portion 14b.
The flat surface of the electric heater 15
Is installed.

Therefore, in the first embodiment, the heating capacity of the electric motor 15 is set at a value of 1 K from the extremely low temperature of 40 K transferred from the heat stage 29 to the temperature of the cold panel 14.
The refrigerating capacity of the refrigerator 13 is set to a capacity capable of controlling the temperature range of 30 K,
As a capability that can be set to K, the temperature of the cold panel 14 is controlled to the above-mentioned temperature range of 80 K to 130 K by controlling the heating of the heater 15.

Thus, the electric heater 15 is capable of arbitrarily adjusting the heating capacity thereof. A temperature detector for detecting the temperature of the cold panel 14 is used, and the detection result from the temperature detector is used. Accordingly, the heating capacity is controlled so that the cold panel 14 has a predetermined temperature set in advance, for example, 80K. By controlling the temperature by this capacity adjustment, even if the cold panel temperature of the refrigerator 13 is set to 40K, Therefore, even if the performance is reduced, the temperature of the cold panel 14 can be maintained at an optimum temperature at which the evacuation of moisture can be effectively performed.

That is, if the seal ring 26 of the refrigerator 13 is worn due to use and leaks, the refrigerating capacity is reduced. In this case, too, by adjusting the heating capacity to a low level, the cold panel 14 can be used. Can be maintained, and by using the refrigerator 13 having a sufficient refrigerating capacity as described above, the permissible capacity reduction can be increased. Therefore, overhaul such as replacement of the seal ring 26 can be performed. The time can be lengthened, and the operation rate of the entire apparatus can be improved. Further, in a state where the refrigerating capacity is set to a large value,
By adjusting the heating capacity of the cold panel 1
In addition to controlling the temperature in the above-mentioned temperature range (80K to 130K), the temperature can be adjusted to a temperature lower than this temperature range. It can also be used as a cryopump other than as a cryogenic pump, which can broaden the application range and improve versatility.

Further, at the time of cooling down, the heater 1
By stopping the heating of the cooling panel 5, the cooling down time can be reduced in conjunction with the increase in the refrigerating capacity, and when the refrigerator 13 is stopped, the temperature can be raised to room temperature in a short time. The regeneration time for removing the water condensed in water can be shortened.

Next, a second embodiment shown in FIGS.

In the second embodiment shown in FIGS. 4 and 5, the trap body 10 is provided at one end with a heat absorbing portion 35a which is exposed to the outside of the trap body 10 and absorbs heat from the outside air. A rod-shaped heat conductor 35 having a heat radiating portion 35b that protrudes into the trap body 10 and comes into contact with the cold panel 14 is provided.

In this case, the amount of heat absorbed from the outside air temperature in the heat absorbing portion 35a is radiated from the heat radiating portion 35b to the cold panel 14, and a heat load is applied to the cold panel 14. Even if the refrigerating capacity of 13 is increased, the temperature of the cold panel 14 can be maintained in the above-mentioned temperature range.

Therefore, according to this embodiment, since the cold panel 14 is not excessively cooled, the exhaust of the process gas such as the argon gas can be prevented, and the exhaust of the moisture can be effectively performed while the consumption amount can be reduced. In addition, the refrigerating capacity can be increased as much as possible, and the capacity reduction allowable amount can be increased, and the advantage that the overhaul time can be extended can be obtained.

In this embodiment, the heat conductor 3
5 is detachable, and by changing its diameter, the heat load applied to the cold panel 14 can be adjusted.
Also, as shown in FIGS. 4 and 5, the heat load can be adjusted by attaching a heat absorbing plate 36 to the heat absorbing portion 35a or by changing the size and number of the heat absorbing plate 36. .

Further, in the second embodiment, the structure can be simplified as compared with the first embodiment, and the time for reproduction is longer than in the first embodiment using the heater 15. Since the time required to raise the temperature to room temperature can be reduced as compared with the conventional example, the regeneration time can be shortened accordingly.

In the third embodiment shown in FIGS. 6 and 7, the heat absorbing portion 35a and the heat radiating portion 35b of the heat conductor 35 are separately formed, and the heat absorbing portion 35a is formed in a cylindrical shape. A heat transfer portion 37 which protrudes into the inside of the trap body 10 and faces the heat radiating portion 35b is provided on the inside, and the heat radiating portion 35b is formed in a solid shape by, for example, an iron material which contracts due to a decrease in temperature, and The heat dissipating portion 35b is provided with a head portion 38 having a large diameter at a tip portion thereof, and a receiving portion 39 with which the head portion 38 contacts is provided at a tip portion of the heat transfer portion 37. When the cold panel 14 is cooled to a predetermined temperature or lower, a heat conducting portion 40 is provided in which the heat dissipating portion 35b and the heat transfer portion 37 come into contact with each other by thermal contraction.

As shown in FIG. 8, the heat conducting section 40 takes into consideration the amount of heat shrinkage with respect to the temperature of the heat radiating section 35b, and the temperature of the cold panel 14 is set in advance to, for example, 80.
The gap d between the head 38 and the receiving part 39 is designed so that the head 38 comes into contact with the receiving part 39 due to the heat shrinkage when the temperature becomes lower than K. In the case of 80K or more, the heat conducting part 40 is not in contact, and the heat load from the heat absorbing part 35a is not given.

Therefore, according to the above configuration, the heat conductor 35 can be provided with an automatic heat load adjusting function.
Until the cold panel 14 reaches a preset temperature of 80K, no heat load is applied, so that the cool-down time can be shortened as compared with the second embodiment. Is not applied, the heat loss can be reduced, and if the cold panel 14 is lower than 80K, the heat load is applied by contact with the heat conducting part 40, so that the cold panel 14
Is not too cold, and can be maintained at a preset optimum temperature. Also in this embodiment, since the cold panel 14 can be maintained at the optimum temperature by the above-mentioned heat load even if the cold panel 14 is too cold, the condensation of the process gas such as the argon gas can be prevented, and the refrigerating capacity is also sufficient. Therefore, there is an advantage that the capacity reduction allowable amount can be increased and the overhaul time can be lengthened.

Next, a fourth embodiment shown in FIGS. 9 and 10 will be described.

In the fourth embodiment shown in FIGS. 9 and 10, between the heat stage 29 and the cold panel 14, a spacer 41 made of a material whose heat transfer coefficient is reduced in a low temperature range below a predetermined temperature is provided. It was dressed.

When the lower limit control temperature of the cold panel 14 is set to, for example, the above-mentioned 80K, the material of the spacer 41 increases the heat transfer coefficient as the temperature decreases up to the above-mentioned 80K. For example, sapphire or the like, whose heat transfer coefficient decreases sharply when it reaches, is selected.

Therefore, the spacer 41 is interposed between the heat stage 29 and the cold panel 14, and the heat stage 29 and the cold panel 14 are thermally connected to each other by the spacer 41. Stage 29
Is transmitted to the cold panel 14 with a good heat transfer coefficient until the temperature reaches a preset 80K.
Is reached, the heat is transferred to the cold panel 14 with a poor heat transfer coefficient, so that the temperature of the cold panel 14 can be suppressed from lower than 80 K, and the exhaust of process gas such as argon gas due to excessive cooling can be suppressed. In addition, since the heat transfer from the heat stage 29 to the cold panel 14 can be adjusted by the spacer 41, it is possible to use the refrigerator 13 having a sufficient refrigerating capacity. It is possible to expect an effect that the capacity reduction allowance can be increased and the overhaul time can be lengthened, and the cool down time can be shortened.

Although the above embodiment has been described with reference to the case where the present invention is applied to a vacuum pump using a cryopump, the present invention can also be applied to a vacuum pump using a vacuum pump such as a molecular pump other than the cryopump.

[0042]

As described above, in any case, the present invention raises the temperature of the cold panel 14 with respect to the temperature of the heat stage 29, and controls the temperature to a predetermined temperature.
Therefore, the temperature of the cold panel 14 can be effectively exhausted, and the temperature of the cold panel 14 can be maintained in an optimum temperature range in which the process gas does not condense. In addition to this, it is possible to prevent the process gas from being exhausted due to the temperature of the cold panel 14 being too low.

Further, since it is not necessary to control the temperature of the cold panel 14 by adjusting the capacity on the refrigerator side, a refrigerator having a sufficient refrigerating capacity can be used.
The capacity reduction allowance can be increased, and the overhaul time can be extended.

Further, according to the first aspect of the present invention using the electric heater 15 while obtaining the above-described functions and effects, the cold
A flat surface of the heat stage 29 on the surface of the flat portion of the panel 14
The heat transfer is good because the parts are attached.
It is easy and reliable, and the back of the flat part of the cold panel 14
Since the flat part of the electric heater 15 is attached to the
Well, the installation is easy and reliable. In addition, since the temperature of the electric heater 15 can be arbitrarily adjusted and the adjustment range can be increased, a refrigerator having a larger refrigerating capacity can be used, and therefore, the permissible capacity decrease can be increased. As a result, the cool down time can be further shortened, and the temperature of the cold panel 14 can be arbitrarily adjusted. Therefore, the temperature of the cold panel 14 can be raised to room temperature in a short time. The regeneration time for removing water can also be reduced.

Further, since the refrigerating capacity of the refrigerator can be increased and the temperature of the heat stage 29 can be lowered, the temperature can be controlled by the heater 15 so that not only moisture but also other gases can be exhausted. Its application range can be expanded, and versatility can be improved.

Further, in the second invention using the heat conductor 35, since the outside air temperature is utilized without using a special heat source as in the first invention, the structure can be simplified and energy consumption can be reduced. However, it has the advantage that the above-mentioned effects can be obtained.

The heat absorbing portion 35a and the heat radiating portion 35b of the heat conductor 35 are divided so that the cold panel 14 is cooled between the heat absorbing portion 35a and the heat radiating portion 35b below a predetermined temperature. When the heat conducting portion 40 to be contacted is provided, the cool-down time can be shortened while the operation and effect of the second invention are obtained, and a heat load is not applied at a predetermined temperature, so that heat loss is correspondingly reduced. The advantage is that it can be reduced.

Further, when a spacer 41 made of a material having a low heat transfer coefficient in a low temperature range below a predetermined temperature is interposed between the heat stage 29 and the cold panel 14,
This has the advantage that the structure can be simplified and the cool down time can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an enlarged cross-sectional view in which only a refrigerator is enlarged.

FIG. 4 is a plan view showing a second embodiment.

FIG. 5 is a sectional view taken along line BB in FIG. 4;

FIG. 6 is a plan view showing a third embodiment.

FIG. 7 is a sectional view taken along line CC of FIG. 5;

FIG. 8 is a partially enlarged cross-sectional view showing the operation of a heat conducting unit.

FIG. 9 is a plan view showing a fourth embodiment.

FIG. 10 is a sectional view taken along line DD in FIG. 7;

FIG. 11 is a schematic view showing an example of a vacuum evacuation apparatus to which the cold drip of the present invention is applied.

FIG. 12 is a sectional view showing a conventional example.

[Explanation of symbols]

 2 Vacuum chamber 3 Cryopump 10 Trap body 11 Exhaust inlet 12 Exhaust outlet 13 Refrigerator 14 Cold panel 15 Electric heater 35 Heat conductor 35a Heat absorbing part 35b Heat radiating part 37 Heat transmitting part 40 Heat conductive part 41 Spacing

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B01D 8/00

Claims (4)

(57) [Claims] 1. A cold trap interposed in an evacuation path of an evacuation device for a vacuum chamber 2, wherein the evacuation inlet portion 11 communicating with the vacuum chamber 2 and the evacuation outlet portion 12 communicating with the evacuation device are provided. A trap body 10 provided with the inlet 11 and the outlet 1 of the trap body 10.
2, a heat stage 29 of the refrigerator 13 and a cold panel 14 thermally connected to the heat stage 29 are provided therein, and the cold panel 14 is provided with an electric heater.
15 while the cold panel 14 is
14a and a flat portion obtained by flattening a part of the cylindrical portion 14a.
14b, and a heat sink is formed on the surface of the flat portion 14b.
Place the flat part of the stage 29 on the back side of the electric heater 15.
A cold trap for a vacuum evacuation device having a surface attached . 2. A cold trap interposed in an evacuation path of an evacuation device for the vacuum chamber 2, wherein the evacuation inlet portion 11 communicating with the vacuum chamber 2 and the evacuation outlet portion 12 communicating with the evacuation device are provided. A trap body 10 provided with the inlet 11 and the outlet 1 of the trap body 10.
2, a heat stage 29 of the refrigerator 13 and a cold panel 14 which is thermally connected to the heat stage 29 are provided therein, and the trap body 10 is exposed to the outside of the trap body 10 from outside air. Endothermic part 35 that absorbs heat
a vacuum conductor having a heat conductor 35b at one end and a heat radiating portion 35b protruding into the inside of the trap body 10 and contacting the cold panel 14 at the other end. Cold trap. 3. The heat absorbing portion 35a of the heat conductor 35 and the heat radiating portion 3
5b are separately formed, and the heat absorbing portion 35a includes a heat transfer portion 37 that protrudes into the trap body 10 and faces the heat radiating portion 35b, and the heat radiating portion 35b contacts and supports the cold panel 14. 3. A heat conducting portion 40 is provided between the heat dissipating portion 35b and the heat transfer portion 37, the heat conducting portion 40 contacting by thermal deformation when the cold panel 14 is cooled below a predetermined temperature. Cold trap of vacuum pumping equipment. 4. A cold trap interposed in an evacuation path of an evacuation device for the vacuum chamber 2, wherein the evacuation inlet portion 11 communicating with the evacuation chamber 2 and the evacuation outlet portion 12 communicating with the evacuation device are provided. A trap body 10 provided with the inlet 11 and the outlet 1 of the trap body 10.
In addition, a heat stage 29 of the refrigerator 13 and a cold panel 14 thermally connected to the heat stage 29 are provided between the heat stage 29 and the heat stage 29. A cold trap for an evacuation apparatus, comprising a spacer 41 made of a material having a low heat transfer coefficient in a region.