JP2000283036A - Cryopump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exchange only a sheath heater and also make a device compact. SOLUTION: In a cryopump 1 arranged the cold cylinder 17 of a refrigerator 3 as well as a sheath heater 53 in a vacuum chamber 5 and installed the first/ second heaters 55, 56 of this sheath heater to the first/second cold heads 33, 35 of the cold cylinder respectively, the first/second heaters of the sheath heater are installed to the first/second cold heads by using installation bolts 58, 59 respectively and attachably/detachably and also a heater flange 57 on one end of the sheath heater is installed to the cylinder base 23 of the cold cylinder from the outside of the vacuum chamber by using installation bolts 60 attachably/detachably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryopump used for generating a high vacuum pressure in a semiconductor manufacturing process or the like.
In particular, it relates to a cryopump equipped with a regeneration heater.

[0002]

2. Description of the Related Art In order to maintain a processing space in a high vacuum state, various types of processing equipment and the like in a semiconductor manufacturing line are provided with a mechanical vacuum pump (hereinafter referred to as a roughing pump) and a cryopump 100 (FIG. 5). , 200 (FIG. 6). The cryopumps 100 and 200 evacuate the processing space roughly evacuated by the roughing pump to further increase the vacuum pressure.
1, the cold cylinders 102 of the refrigerators 101 and 201,
The apparatus includes a cold panel 203 held by a 202, an activated carbon 204 adhered to the surface of the cold panel 203, vacuum chambers 105 and 205 for accommodating the cold cylinders 102 and 202, the cold panel 203, and the like. The evacuation by the cryopumps 100 and 200 is performed by condensing and solidifying gas molecules on the surface of the cold panel 203 cooled to a very low temperature, or by adsorbing gas molecules on the adsorption surface of the activated carbon 204.
The inside of 205 is set to a high vacuum pressure.

In the cryopumps 100 and 200, when an evacuation operation is performed for a long time, condensation and adsorption of gas molecules on the surface of the cold panel 203 and the adsorption surface of the activated carbon 204 gradually progress, and the evacuation efficiency is reduced. And exhaust can hardly be performed at the end. Therefore, it is necessary to appropriately perform a regeneration operation for releasing the condensed or adsorbed gas molecules. In this case, a regeneration gas (generally, a nitrogen gas) is introduced into the vacuum chambers 105 and 205, and the cold panel 203 and the The temperature of the cold cylinders 102, 202 will be raised to near normal temperature.

By the way, 100, 20 with a cryopump
0, the cold cylinders 102, 202 during the exhaust operation
Temperature is extremely low (about 20K) and normal temperature (25 ° C)
(= About 298 K)) is very large (28
0K). Therefore, when the temperature is raised only by introducing the regeneration gas at normal temperature, it takes a long time from the start of the regeneration operation to the release of the gas molecules, so that the semiconductor production line must be stopped for a long time. And the production efficiency had to be reduced.

Therefore, the cryopumps 100 and 200 have the heaters 106 and the cold cylinders 102 and 202.
The heater 206 is mounted, and the heaters 106 and 206 are connected to a power supply provided outside the vacuum chambers 105 and 205 by electric wires. By supplying power to the heaters 106 and 206 during the regeneration operation, the cold cylinders 102 and 202 are quickly heated to room temperature, and the regeneration operation time is greatly reduced.

[0006]

One end 107 of the heater 106 of the cryopump 100 shown in FIG.
Are fixed to the cylinder base 108 of the cold cylinder 102 by welding. For this reason, when a failure such as disconnection occurs in the heater 106, only the heater 106 cannot be replaced, and the heater 106 must be replaced together with the cold cylinder 102, which increases the cost.

A heater flange 2 fixed to one end of the heater 206 of the cryopump 200 shown in FIG.
Reference numeral 07 is detachably attached to the bottom plate 208 of the vacuum chamber 205 from outside the vacuum chamber 205 by using attachment bolts 209. Therefore, only the heater 206 can be replaced.

However, in this heater 206, since the body 210 of the refrigerator 201 exists outside the vacuum chamber 205, the heater flange 2 of the heater 206
07, the mounting tool is the body 21 of the refrigerator 201.
It is necessary to attach the heater flange 207 of the heater 206 away from the body 210 so as not to interfere with zero. Therefore, the diameter of the vacuum chamber 205 increases, and the size of the cryopump 200 increases.

The object of the present invention has been made in view of the above-mentioned circumstances, and only the heater can be replaced.
An object of the present invention is to provide a cryopump capable of downsizing the device.

[0010]

According to the first aspect of the present invention, a cold cylinder of a refrigerator is provided in a vacuum chamber and a heater is provided, and a heating unit of the heater is provided in the vacuum cylinder. In a cryopump attached to a cooling unit, a heating unit of the heater is detachably attached to the cooling unit, and an end of the heater is detachably attached to a cylinder base of the cold cylinder from outside the vacuum chamber. It is characterized by having been done.

According to a second aspect of the present invention, there is provided a cryo-cooler in which a cold cylinder of a refrigerator is provided in a vacuum chamber and a heater is provided, and a heating section of the heater is attached to a cooling section of the cold cylinder. In the pump, a heating unit of the heater is detachably attached to the cooling unit, and an end of the heater is detachably attached to a cylinder base of the cold cylinder from inside the vacuum chamber. Is what you do.

The first aspect of the invention has the following operation.

The heater of the heater is detachably attached to the cooling unit of the cold cylinder, and the end of the heater is detachably attached to the cylinder base of the cold cylinder. Only one can be replaced, and the cost can be reduced.

Further, since the end of the heater is mounted not on the bottom plate of the vacuum chamber, but on the cylinder base of the cold cylinder, the mounting tool and the refrigerator existing outside the vacuum chamber are attached when the heater end is mounted. Since it is not necessary to increase the diameter of the vacuum chamber in consideration of interference with the body, the cryopump can be made compact.

Further, since the heater end is attached to the cylinder base from outside the vacuum chamber, the attachment of the heater end can be facilitated.

The second aspect of the present invention has the following operation.

Since the heating section of the heater is detachably attached to the cooling section of the cold cylinder and the end of the heater is detachably attached to the cylinder base of the cold cylinder, the heater is detached from the cold cylinder and the heater is removed. Only one can be replaced, and the cost can be reduced.

Further, since the end of the heater is mounted not on the bottom plate of the vacuum chamber but on the cylinder base of the cold cylinder, a tool for mounting the heater at the time of mounting the end of the heater and a refrigerator provided outside the vacuum chamber are provided. Since it is not necessary to increase the diameter of the vacuum chamber in consideration of interference with the body, the cryopump can be made compact.

Further, since the heater end is attached to the cylinder base from inside the vacuum chamber, interference between the mounting tool and the refrigerator body outside the vacuum chamber when attaching the heater end is taken into consideration. Therefore, the heater end can be mounted closer to the center axis of the cold cylinder. As a result, the diameter of the cold cylinder and the vacuum chamber can be reduced, and the size of the cryopump can be further reduced.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

[A] First Embodiment (FIGS. 1 and 2) FIG. 1 is a side view, partially broken away, showing a first embodiment of a cryopump according to the present invention.

As shown in FIG. 1, the cryopump 1 of the present embodiment includes a cryogenic refrigerator 3 using a Gifford-McMahon cycle, a cylindrical body 47A,
47B is composed of a vacuum chamber 5 and the like connected in series,
It is attached to a vacuum processing tank (not shown) of a semiconductor wafer manufacturing line. A gate valve is provided between the body 47B of the vacuum chamber 5 and the vacuum processing tank, and a sliding valve (not shown) of the gate valve communicates the vacuum processing tank with the vacuum chamber 5 of the cryopump 1. Cut off.

The refrigerator 3 incorporates a body 15 disposed outside the vacuum chamber 5, a cold cylinder 17 disposed in a body 47A of the vacuum chamber 5, and a regenerator that slides in the cold cylinder 17 in the axial direction. Displacer 19
(FIG. 2), and is configured by an electric motor 25 for driving the displacer 19 via a crank mechanism (not shown) and the like. The bearing plate 21 of the body 15 is, as shown in FIG.
Is fixed by using a mounting bolt 7.

The body 15 of the refrigerator 3 has a refrigerant introduction pipe 27
And a refrigerant discharge pipe 29 connected to a compressor unit (not shown), and helium gas as a refrigerant circulates between the refrigerator 3 and the compressor unit. The vacuum chamber 5 is connected to a roughing pump (not shown) via a roughing pipe (not shown), and the vacuum pump 5 performs roughing of the vacuum chamber 5.

As shown in FIG. 1, the cold cylinder 17
A first cold head 33 as a cooling unit having a relatively large mass is formed at a substantially middle position in the vertical direction, and a second cold head 35 as a cooling unit having a relatively small mass is formed at the upper end. In the second cold head 35,
A radiation shield 37 opened to the side is attached. The radiation shield 37 is formed in a cylindrical shape having a slightly smaller diameter than the body portion 47A of the vacuum chamber 5, and a plurality of baffle rings 4 are provided inside the opening portion 31.
3 is held.

Further, a cold panel holder (not shown) is attached to the second cold head 35, and the cold panel holder comprises a plurality of cold panels (not shown).
Holding. Activated carbon is adhered to the upper surface of the cold panel except for a part.

On the other hand, as described above, the vacuum chamber 5 has a body portion 47A for housing the cold cylinder 17 and a body portion 47B for housing the radiation shield 37 and the like, which are orthogonally connected to each other. The body 47 </ b> A is bolted to the cylinder base 23 of the cold cylinder 17 using the mounting bolt 11. A regeneration gas introduction pipe (not shown) connected to a regeneration gas supply source (not shown) is connected to the vacuum chamber 5 and opened, and a regeneration gas discharge pipe (not shown) connected to an exhaust processing device (not shown) penetrates. ing. The regeneration gas introduction pipe is open inside the radiation shield 37.

In the vacuum chamber 5, a sheath heater 53 as a heater removably attached to the cold cylinder 17 is provided. The sheath heater 53 is used for controlling the temperature of the first cold head 33 and the second cold head 35 of the cold cylinder 17 or for shortening the regeneration time of the cryopump 1.

The sheath heater 53 includes a heater pipe 6
1. It has a heating coil and a heater flange 57 (not shown). The heating coil is installed in the heater pipe 61 at a position corresponding to a first heating unit 55 and a second heating unit 56 described below, and is connected to a power supply device (not shown) via an electric wire 62 (FIG. 2). In addition, heater flange 5
7 is integrated with one end of the heater pipe 61 from which the electric wire 62 is taken out by welding or brazing.

The sheath heater 53 is inserted into the vacuum chamber 5 through an insertion hole 54 formed in the cylinder base 23 of the cold cylinder 17, as shown in FIG. In the sheath heater 53, the first heating unit 55 uses the mounting bolt 58 for the first cold head 33 of the cold cylinder 17, and the second heating unit 56 uses the mounting bolt for the second cold head 35 of the cold cylinder 17. Using 59, each is detachably bolted. further,
The heater flange 57 is detachably bolted to the cylinder base 23 from the outside of the vacuum chamber 5 (that is, from the atmosphere side) using a mounting bolt 60.

A sealing material such as an O-ring is interposed between the heater flange 57 and the cylinder base 23 to keep the inside of the vacuum chamber 5 airtight.
High vacuum pressure inside is ensured. Reference numeral 63 in FIGS. 1 and 2 denotes an electric wire case that accommodates the electric wire 62 drawn out of the sheath heater 53. The electric wire case 63 is bolted to the heater flange 57 using the mounting bolt 60.

The operation of the present embodiment will be described below.

During the sputtering process of the semiconductor wafer or the like, the inside of the vacuum processing tank is kept at a high vacuum pressure in order to prevent unnecessary gas molecules from adhering to the surface of the semiconductor wafer. First, a vacuum pressure of about 10 −2 Torr is obtained by roughly vacuuming the vacuum chamber 5 using a roughing pump. At this point, communication between the vacuum chamber 5 and the vacuum processing tank is interrupted by the gate valve.

Next, the refrigerator 3 of the cryopump 1 is driven to reciprocate the displacer 19 in the cold cylinder 17, and the high-pressure helium gas supplied from the compressor is repeatedly adiabatically expanded in the cold cylinder 17. Then, the cold storage material in the displacer 19 is gradually cooled, and the temperature of the cold cylinder 17 decreases. Then, when the temperature of the first cold head 33 becomes about 80K and the temperature of the second cold head 35 becomes about 15K, the gate valve is opened to connect the vacuum chamber 5 with the vacuum processing tank. At this time, the vacuum processing tank is roughly evacuated to a crossover pressure or lower by a roughing pump (not shown).

When the vacuum chamber 5 is communicated with the vacuum processing tank, gas molecules in the vacuum processing tank are condensed or adsorbed in the radiation shield 37, and a high vacuum pressure is obtained. That is, gas molecules having a high condensation temperature, such as water, condense and solidify in the form of frost on the surface of the baffle ring and the radiation shield 37, and gas molecules such as argon, oxygen, and nitrogen condense in the form of frost on the surface of the cold panel.・ It solidifies. Further, gas molecules such as helium, hydrogen, and neon are adsorbed on activated carbon adhered to the cold panel. This allows
In the vacuum processing tank 7, a high vacuum pressure of about 10-9 Torr can be obtained.

On the other hand, when the evacuation by the cryopump 1 is performed continuously, the surfaces of the baffle ring and the cold panel are covered with the condensed gas molecules, the evacuation efficiency is reduced, and a high vacuum pressure cannot be obtained. Therefore, when the temperature of the second cold head 35 does not drop below a predetermined value or when a predetermined vacuum pressure cannot be obtained, the cryopump 1 is regenerated.

At the time of regeneration, the communication between the vacuum chamber 5 and the vacuum processing tank is cut off by a gate valve.
The heating coil in the sheath heater 53 is energized, and the first,
The second cold head 33 and the second cold head 35 are heated. Then, gas molecules condensed on the baffle ring, the cold panel, and the like are vaporized, and are discharged from the regeneration gas discharge pipe together with the regeneration gas introduced from the regeneration gas introduction pipe.

Therefore, according to the above embodiment, the following effects are obtained.

The first heating section 55 and the second heating section 56 of the sheath heater 53 are detachably attached to the first cold head 33 and the second cold head 35 of the cold cylinder 17 by using mounting bolts 58 and 59, respectively. The sheath heater 53 is detached from the cold cylinder 17 at the time of disconnection of the sheath heater 53 because the heater flange 57 at one end of the sheath heater 53 is detachably attached to the cylinder base 23 of the cold cylinder 17. Therefore, only the sheath heater 53 can be replaced, and the cost can be reduced as compared with the case where the entire cold cylinder 17 is replaced.

Since the heater flange 57 at one end of the sheath heater 53 is attached to the cylinder base 23 of the cold cylinder 17 instead of the bottom plate of the vacuum chamber 5, when the heater flange 57 is attached at one end of the sheath heater 53, The cryopump 1 can be made compact because it is not necessary to increase the diameter of the vacuum chamber 5 in consideration of the interference between the third body 15 existing outside the 5 and the mounting tool.

Since the heater flange 57 at one end of the sheath heater 53 is attached to the cylinder base 23 from outside the vacuum chamber 5, the sheath heater 53
Can easily be attached to the heater flange 57 at one end.

[B] Second Embodiment (FIGS. 3 and 4) FIG. 3 is a side view, partially cut away, of a second embodiment of a cryopump according to the present invention. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The cryopump 7 of the second embodiment
0, the heater flange 57 of the sheath heater 53 is attached to the mounting bolt 60 from the inside of the vacuum chamber 5 (that is, from the vacuum side).
Using the cylinder base 23 of the cold cylinder 17
Bolted to Further, the electric wire 62 drawn out of the heater pipe 61 of the sheath heater 53 is inserted into the insertion hole 54 of the cylinder base 23 and the insertion hole 71 formed in the bearing plate 21 and is accommodated in the electric wire case 63. The electric wire case 63 is fixed to the bearing plate 21 by bolts using mounting bolts 72.

Therefore, according to the cryopump 70 of the second embodiment, the following effects are obtained.

The first heating unit 55 and the second heating unit 56 of the sheath heater 53 are attached to the first cold head 33 and the second cold head 35 of the cold cylinder 17 by using attachment bolts 58 and 59, respectively. Since the heater flange 57 at one end of the sheath heater 53 is detachably attached to the cylinder base 23 of the cold cylinder 17, when the sheath heater 53 is disconnected, the sheath heater 53 is detached from the cold cylinder 17, and the sheath heater 53 is removed. Only 53 can be replaced, and the cost can be reduced as compared with the case where the entire cold cylinder 17 is replaced.

Since the heater flange 57 at one end of the sheath heater 53 is attached to the cylinder base 23 of the cold cylinder 17 instead of the bottom plate of the vacuum chamber 5, when the heater flange 57 at one end of the sheath heater 53 is attached, the vacuum chamber Since there is no need to increase the diameter of the vacuum chamber 5 in consideration of the interference between the body 15 of the refrigerator 3 and the mounting tool existing outside the vacuum chamber 5,
The cryopump 70 can be compact.

Since the heater flange 57 at one end of the sheath heater 53 is attached to the cylinder base 23 from inside the vacuum chamber 5, the sheath heater 53
When attaching the heater flange 57 at one end of the
The body 15 of the refrigerator 3 existing outside the vacuum chamber 5
It is not necessary to consider the interference between the sheath heater 53 and the mounting flange, so that the heater flange 57 at one end of the sheath heater 53 can be mounted close to the central axis O of the cold cylinder 17. As a result, the diameter of the cold cylinder 17 and the vacuum chamber 5 can be reduced, and the central axis O of the cryopump 70 can be reduced.
M can be made smaller than the distance N between the central axis O of the cryopump 1 and the electric wire case 63 in FIG. 1, so that the cryopump 70 can be made more compact than the cryopump 1.

As described above, the present invention has been described based on the above embodiment, but the present invention is not limited to this.

[0049]

As described above, according to the cryopump according to the present invention, the heating section of the heater is detachably attached to the cooling section, the end of the heater is attached to the cylinder base of the cold cylinder, Since it is detachably attached from the outside, only the heater can be replaced and the device can be made compact.

[Brief description of the drawings]

FIG. 1 is a side view, partially broken away, of a first embodiment of a cryopump according to the present invention.

FIG. 2 is an exploded side view showing a part around a cylinder base in the cryopump shown in FIG.

FIG. 3 is a side view showing a second embodiment of the cryopump according to the present invention, with a part thereof broken away.

FIG. 4 is an exploded side view showing a part around a cylinder base in the cryopump shown in FIG.

FIG. 5 is a side view showing a conventional cryopump.

FIG. 6 is a side view showing another conventional cryopump.

[Explanation of symbols]

 Reference Signs List 1 cryopump 3 refrigerator 5 vacuum chamber 17 cold cylinder 23 cylinder base 33 first cold head (cooling unit) 35 second cold head (cooling unit) 53 sheath heater (heater) 55 first heating unit (heating unit) 56 second Heating part (heating part) 57 Heater flange (one end) 58 Mounting bolt 59 Mounting bolt 60 Mounting bolt 70 Cryopump

Claims (2)

[Claims] 1. A cryopump, wherein a cold cylinder of a refrigerator is provided in a vacuum chamber and a heater is provided, and a heating section of the heater is provided in a cooling section of the cold cylinder. A cryopump, wherein a portion is detachably attached to the cooling unit, and an end of the heater is detachably attached to a cylinder base of the cold cylinder from outside the vacuum chamber. 2. A cryopump in which a cold cylinder of a refrigerator is provided and a heater is provided in a vacuum chamber, and a heating section of the heater is provided in a cooling section of the cold cylinder. A cryopump, wherein a portion is detachably attached to the cooling unit, and an end of the heater is detachably attached to a cylinder base of the cold cylinder from inside the vacuum chamber.