JP2551204B2 - Cryopump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is suitable for vacuuming the processing chamber of a sputtering apparatus used in the manufacturing sector of semiconductors, magnetic disks, optical disks, etc., and is mainly used for argon gas. The present invention relates to a cryopump suitable for exhausting air.

(Prior Art) Conventionally disclosed in Japanese Patent Application Laid-Open No. 60-13992 and the like
As shown in the figure, this type of cryopump includes a gas expansion type refrigerator body (R) using helium, a first heat stage (X) having an absolute temperature of several tens of K level, and a second heat stage having a temperature lower than this. A first panel (A) that includes a heat stage (Y), covers the second heat stage (Y) on the first heat stage (X), and includes a baffle (W) at a gas intrusion portion.
And a plurality of umbrella-shaped panels (P) having a second heat stage (Y) and a hydrogen adsorption layer (H) such as activated carbon formed on the back surface thereof.
Each of the second panels (B) consisting of (1) and (2) is connected to each other, and the first panel (A) prevents heat from entering from the pump case (C) side and the like, and condenses the argon gas on the surface of the second panel (B). At the same time, hydrogen is adsorbed on the hydrogen adsorption layer (H) on the back surface, and a vacuum is drawn in the processing chamber.

(Problems to be solved by the invention) By the way, using an argon gas in a sputtering apparatus or the like,
In order to exhaust a large amount of used argon gas, it is necessary to simultaneously exhaust the hydrogen gas at the same time so as not to saturate the hydrogen gas mixed with the argon gas (mainly hydrogen gas released from the cathode material). . In the conventional structure described above, since the second panel (B) is composed of a plurality of umbrella-shaped panels (P), compared with the case where the second panel (B) is simply a bottomed tubular panel, It is possible to secure a wide area for adhering hydrogen and an area for adsorbing hydrogen, and at first glance, it seems to be suitable for large-scale exhaust of argon gas.

However, in practice, as shown in the figure, when the deposition of argon (a) progresses, the gap between the upper and lower sides of each umbrella-shaped panel (P) is closed and the hydrogen adsorption layer (H) hidden inside is used. Is not possible, and the hydrogen is exhausted only by the hydrogen adsorption layer (H) at the bottom end, and therefore,
There is a problem that the exhaust amount of hydrogen is suppressed, and accordingly, the exhaust amount of argon is also suppressed.

Also, argon (a) is on the upper surface of the second panel (B),
Since it is deposited in the space between the first panel (A) and the baffle (W) having a high temperature level, the amount of deposition can be increased by increasing the temperature between the first panel (A) and the baffle (W). It is necessary to make the space large, and it is desirable to make the second panel (B) smaller than the first panel (A). However, if the second panel (B) is downsized, the space between the umbrella-shaped panels (P) becomes narrower. Further, in order to compensate for the reduction in the hydrogen adsorption area due to the size reduction, when the number of the umbrella-shaped panels (P) is increased, the interval becomes narrower. Therefore, when the argon (a) is deposited, the hydrogen adsorption layer (H ) Is blocked very easily, it is difficult to downsize the second panel (B), that is, to enlarge the deposition space, and there is a problem that the exhaust amount of argon is limited. In addition, when the first panel (X) is enlarged to enlarge the deposition space without downsizing the second panel (B), there is a problem that the entire apparatus is enlarged.

Therefore, even if the second panel (B) is composed of the umbrella-shaped panel (P) as in the conventional case, there is no remarkable difference from the case where the second panel (B) is simply a bottomed tubular panel. The cumulative displacement of argon is, for example, a standard pump with a gas intrusion part having a diameter of about 300 mm, at most 2000 SL; standard
The liter (0 ° C., 1 atm) is the limit, and there is a problem that performance is insufficient for application to a sputtering device.

In the present invention, by devising the structure of the second panel, the inflow route to the hydrogen adsorption layer is not closed due to the deposition and deposition of argon, and the hydrogen adsorption amount is not reduced, and the hydrogen adsorption area is sufficient. While ensuring and adsorbing hydrogen favorably, the second panel can be downsized and the argon deposition space in the first panel can be expanded.
An object of the present invention is to provide a cryopump that increases the amount of argon deposition and the amount of argon exhaust and hydrogen exhaust.

(Means for Solving the Problem) Therefore, in the present invention, in order to achieve the above object, the refrigerator main body (10) is provided with the first and second heat stages (1, 2), and the second heat stage ( The first panel (5) which covers the second part (2) and has a baffle (4) at the gas intrusion part is coupled to the first heat stage (1), and is also installed in the first panel (5) to provide a hydrogen adsorption layer. In a cryopump in which a second panel (6) having (7) is coupled to the second heat stage (2), a bottom wall (which couples the second panel (6) to the second heat stage (2) ( 61a) and a bottomed cylindrical outer panel (61) having a cylindrical wall (61b) extending from the outer peripheral portion of the bottom wall (61a) to the side opposite the baffle, and radially arranged inside the outer panel (61). And extends from the back part of the bottom wall (61a) to the hem part of the cylindrical wall (61b). An inner panel (62) composed of a plurality of radial plates (62a), the hydrogen adsorption layer (7) is formed on the inner panel (62), and the adjacent radial plates (62)
Between a), from the back of the bottom wall (61a) to the cylindrical wall (61b)
The radial space (63) is formed continuously over the hem of the.

In the above structure, the outer panel (61) is attached to the cylindrical wall (61b).
We decided to make the outer diameter of the top of the bottom wall (61a) smaller than that of the bottom.

(Operation) From a plurality of radial plates (62a) radially arranged inside the outer panel (61) and extending from the back of the bottom wall (61a) of the outer panel (61) to the hem of the tubular wall (61b) A hydrogen adsorbing layer (7) is formed on the inner panel (62), and between the adjacent radial plates (62a), from the back of the bottom wall (61a) to the hem of the cylindrical wall (61b). Since the continuously formed radial space (63) is provided, the entire hydrogen adsorbing layer (7) is covered from the entire hem opening of the outer panel (61) to the inside of the first panel (5), that is, the gas. It is opened to the invasion route of.

Therefore, while a large amount of argon is being deposited on the surface of the outer panel (61), uncondensed hydrogen is irrelevant from the entire bottom opening of the outer panel (61) regardless of the amount of the deposited argon. Since it can be taken into the outer panel (61) at all times, the probability that hydrogen will enter the inside of the second panel (6) can be maximized, and the hydrogen that enters the second panel (6) will be the panel. The entire hydrogen adsorption layer (7) that allows hydrogen to reach the entire inner panel (61) uniformly by the radial space (63) and not to concentrate on the local adsorption surface inside, and to provide hydrogen to the inner panel (61). Therefore, the exhaust amount of hydrogen and the exhaust amount of argon can be increased.

Further, regardless of the amount of accumulated argon, uncondensed hydrogen is always taken into the outer panel (61) through the entire skirt opening of the outer panel (61) to adsorb hydrogen. Since the hydrogen adsorption layer (7) is not blocked by the deposition and deposition of argon, the size of the second panel (6) can be arbitrarily adjusted to the desired exhaust amount of argon while adsorbing hydrogen favorably. And the size of the second panel (6) can be reduced so that sufficient deposition can be achieved in the space between the baffle (4) and the first panel (5) and the outer panel (61). Since the space can be secured, the deposition amount of argon can be increased and the exhaust amount can be increased.

Moreover, the plurality of radial plates (62) of the inner panel (62) are
a) are radially arranged in the outer panel (61), and these radial plates (62a) are opened into the first panel (5) from the entire hem opening of the outer panel (61). Therefore, it is possible to satisfactorily adsorb hydrogen while sufficiently securing the area of the hydrogen adsorption layer (7) in the limited inner space of the outer panel (61). Second panel (6)
Even if the area of the hydrogen adsorption layer (7) per radial plate (62a) is reduced due to the miniaturization of the above, the area of the hydrogen adsorption layer (7) can be secured sufficiently by increasing the number of the radial plates (62a). can do.

In addition, by making the outer diameter of the top panel smaller than the skirt of the outer panel (61), it is possible to prevent the argon from being unevenly attached to the top portion of the outer panel (61) located upstream of the invasion route, and to prevent the argon from being attached. The outer panel (61) can be satisfactorily cylindrically attached to the outer periphery of the outer panel (61), and the amount of deposition can be further increased.

(Embodiment) In FIG. 1, (10) is a gas expansion type refrigerator main body using helium as a working fluid, and its first freezing cylinder (11)
Is equipped with a first heat stage (1) having an absolute temperature of about 40 to 70K, and a second heat stage (2) having a temperature of about 10 to 20K on the end surface of the second freezing cylinder (12). (3)
Is a cylindrical pump case, and is provided with an intake port flange (8) attached to the processing chamber of the sputtering apparatus on the upper part.

The first heat stage (1) covers the second heat stage (2) and has a plurality of fins (41) at the gas intrusion part.
A first panel (5) having a bottom and having a bottom and having a baffle (4) concentrically provided therein is coupled to block or reduce heat intrusion from the pump case (3) or the processing chamber side. ing.

Then, the second provided on the second heat stage (2)
The panel (6) has a bottomed tubular shape having a bottom wall (61a) for coupling to the second heat stage (2) and a tubular wall (61b) extending from the outer peripheral portion of the bottom wall (61a) to the side opposite to the baffle. An outer panel (61) and a plurality of radially arranged inside the outer panel (61), as shown in FIG. 2, extending from the back of the bottom wall (61a) to the hem of the tubular wall (61b). And an inner panel (62) composed of a radial plate (62a). Then, each radial plate (62) that constitutes the inner panel (62) is
In a), a hydrogen adsorption layer (7) using activated carbon is formed.

Further, a radial space (63) formed continuously from the back of the bottom wall (61a) to the hem of the tubular wall (61b) is provided between the adjacent radial plates (62a).

According to the above configuration, a plurality of radial plates radially arranged inside the outer panel (61) and extending from the back portion of the bottom wall (61a) of the outer panel (61) to the hem portion of the cylindrical wall (61b). A hydrogen adsorption layer (7) is formed on an inner panel (62) made of (62a), and the adjacent radial plates (62) are formed.
Between a), from the back of the bottom wall (61a) to the cylindrical wall (61b)
Since the radial space (63) is formed continuously over the hem of the first panel (5), the entire hydrogen adsorption layer (7) is extended from the entire hem opening of the outer panel (61) to the first panel (5). It is opened to the inside of, that is, the passage of gas.

Therefore, while a large amount of argon is being deposited on the surface of the outer panel (61), uncondensed hydrogen is irrelevant from the entire bottom opening of the outer panel (61) regardless of the amount of the deposited argon. Since it can be taken into the outer panel (61) at all times, the probability that hydrogen will enter the inside of the second panel (6) can be maximized, and the hydrogen that enters the second panel (6) will be the panel. The entire hydrogen adsorption layer (7) that allows hydrogen to reach the entire inner panel (61) uniformly by the radial space (63) and not to concentrate on the local adsorption surface inside, and to provide hydrogen to the inner panel (61). Since the hydrogen adsorption layer is not blocked as in the conventional case, hydrogen can be adsorbed well at all times, and the exhaust amount of hydrogen and the exhaust amount of argon can be increased.

Further, regardless of the amount of accumulated argon, uncondensed hydrogen is always taken into the outer panel (61) through the entire skirt opening of the outer panel (61) to adsorb hydrogen. Since the hydrogen adsorption layer (7) is not blocked by the deposition and deposition of argon, the size of the second panel (6) can be arbitrarily adjusted to the desired exhaust amount of argon while adsorbing hydrogen favorably. Of the baffle (4) and the space between the first panel (5) and the outer panel (61) by reducing the size of the second panel (6). Since the space can be secured, the deposition amount of argon can be increased and the exhaust amount can be increased.

Moreover, the plurality of radial plates (62) of the inner panel (62) are
a) are radially arranged in the outer panel (61), and these radial plates (62a) are opened into the first panel (5) from the entire hem opening of the outer panel (61). Therefore, it is possible to satisfactorily adsorb hydrogen while sufficiently securing the area of the hydrogen adsorption layer (7) in the limited inner space of the outer panel (61). Second panel (6)
Even if the area of the hydrogen adsorption layer (7) per radial plate (62a) is reduced due to the downsizing, the area of the hydrogen adsorption layer (7) will be sufficient by increasing the number of radial plates (62a). Can be secured.

Also, with the above configuration, the outer panel (61) is
The outer diameter of the top part close to the bottom wall (61a) is made smaller than the bottom part of b) to form a taper shape. With this structure, the outer panel (61) in which argon (a) is located upstream of its entry path is ) It is possible to avoid unevenly adhering to the top part of) and become a top-heavy state, and it is possible to satisfactorily adhere the argon (a) to the outer periphery of the outer panel (61) in a cylindrical shape. Can be increased even better.

By the way, with the structure described above, the diameter is about 300 mm
In the case of about 4 to 4, the total argon exhaust capacity is 4000 to 4500
It has been possible to double the SL, which is almost double that of the conventional model.

(Effects of the Invention) As described above, according to the present invention, the bottom panel (61a) coupling the second panel (6) to the second heat stage (2) and the outer circumference of the bottom wall (61a). Bottomed tubular outer panel (6b) having a tubular wall (61b) extending from the section to the side opposite the baffle (6b)
1) and an inner panel (62a) radially arranged inside the outer panel (61) and extending from the back portion of the bottom wall (61a) to the hem portion of the cylindrical wall (61b). 62) to form the hydrogen adsorption layer (7) on the inner panel (62), and between the adjacent radial plates (62a) from the back portion of the bottom wall (61a) to the cylindrical wall. Since the radial space (63) formed continuously over the skirt of (61b) is provided, it is possible to avoid the situation where the inflow path to the hydrogen adsorption layer (7) is blocked by the deposition and deposition of argon, and Since the deposition space of argon can be expanded by downsizing the panel (6) and the adsorption area of the hydrogen adsorption layer (7) can be sufficiently secured, the exhaust amount of argon and the exhaust amount of hydrogen can be increased. It is possible to use a large exhaust port for argon such as for sputtering equipment. It's becomes suitable as a flop.

In this case, if the outer diameter of the outer panel (61) is smaller than that of the bottom of the bottom wall (61a) with respect to the bottom of the tubular wall (61b),
An outer panel (6 with argon located upstream of its entry path)
It is possible to avoid unevenly adhering to the top of 1), and it is possible to favorably adhere argon to the outer periphery of the outer panel (61) in a cylindrical shape, and to further increase the deposition amount. .

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a cryopump according to the present invention, FIG. 2 is a bottom view of the same second panel, and FIG. 3 is a sectional view of a conventional example. (1) …… First heat stage (2) …… Second heat stage (4) …… Baffle (5) …… First panel (6) …… Second panel (7) …… Hydrogen adsorption layer (10) ) …… Refrigerator body (61) …… Outer panel (62) …… Inner panel (61a) …… Bottom wall (61b) …… Cylinder wall (62a) …… Radial plate

Claims (2)

(57) [Claims] 1. A refrigerator main body (10) is provided with first and second heat stages (1, 2), and the second heat stage (2).
And a first panel (5) having a baffle (4) at a gas intrusion part is coupled to the first heat stage (1), and the first panel (5) is internally provided with a hydrogen adsorption layer (7). In a cryopump in which a second panel (6) having (1) is coupled to the second heat stage (2), a bottom wall (61a) coupling the second panel (6) to the second heat stage (2). And a bottomed cylindrical outer panel (61) having a cylindrical wall (61b) extending from the outer peripheral portion of the bottom wall (61a) to the side opposite to the baffle, and arranged radially inside the outer panel (61), A plurality of radial plates (62) extending from the back of the bottom wall (61a) to the hem of the cylindrical wall (61b).
a) and an inner panel (62) made of a), the hydrogen adsorption layer (7) is formed on the inner panel (62), and the bottom wall (61a) is provided between the adjacent radial plates (62a). ), And a radial space (63) formed continuously from the back portion to the hem of the cylindrical wall (61b) is provided. 2. The cryopump according to claim 1, wherein the outer panel (61) has a smaller outer diameter at the bottom wall (61a) side top than the skirt of the cylindrical wall (61b).