JPH10213065A - Variable baffle type cryopump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contrive high speed high evacuation in a cryopump to be used in a vacuum exhaust equipment. SOLUTION: The opening degree (angle) of a first stage baffle 3 is made to have a variable structure in this pump. By always determining an optimum angle in a controller 8 for controlling opening degree from a temperature and a degree of the vacuum within a cryopump and outputting the angle to a first stage baffle driving part 7, the first stage baffle 3 is always varied and controlled to an optimum opening degree. Thus, condensation and adsorption of gas molecule in the first stage baffle 3 and a second stage cryopanel 5 can be efficiently performed, regardless of the state of gas molecule evacuated and exhausted and a pump temperature, and high speed high evacuation becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable baffle type cryopump, and more particularly to a variable baffle type cryopump having a function of increasing an evacuation speed.

[0002]

2. Description of the Related Art As shown in FIG. 4, a conventional cryopump includes a first stage cold head 1, a first stage shield 2 and a first stage baffle 3, a second stage cold head 4, and a first stage cold head 4 connected thereto. , A first stage shield 2 and a first stage baffle composed of an adsorbent attached to the back of the second stage cryopanel 5 and cooled by a He refrigerator 6. 3. Vacuum exhaust is performed by condensing gas in the second stage cryopanel 5.

Next, the operation of vacuum evacuation will be described. H
e The refrigerator 6 cools the first stage cold head 1 and the first stage shield 2 and the first stage baffle 3 connected thereto to 130 K (Kelvin) or less, and connects the second stage cold head 4 to this. The cooled second stage cryopanel 5 is cooled to 20 K (Kelvin) or less. The gas having a low vapor pressure is condensed and solidified in the first stage shield 2 and the first stage baffle 3 among the gas which has jumped from the vacuum chamber to the suction port of the cryopump, and the gas having a high vapor pressure is in the second stage cryopump. Condensed and solidified on the panel 5. Furthermore, the second
Gas molecules that are not condensed even in the stage cryopanel 5 are adsorbed by an adsorbent such as activated carbon attached to the back side of the second stage cryopanel 5. The cryopump is a vacuum pump that evacuates by accumulating gas molecules in the pump as described above.

[0004]

The first problem is that the evacuation speed is reduced depending on the state and type of residual gas molecules in the container to be evacuated. The reason is that since the first stage baffle is fixed, it prevents gas molecules condensed in the second stage cryopanel.

An object of the present invention is to provide a cryopump capable of increasing the evacuation speed.

[0006]

SUMMARY OF THE INVENTION A variable baffle type cryopump according to the present invention comprises a first stage baffle having a variable structure, a first stage baffle opening controller connected to a temperature sensor and a vacuum gauge, and a first baffle opening controller. A first stage baffle drive unit connected to a stage baffle opening control controller and controlled to extend and retract in a circular shape or to have an opening of two-stage switching via a drive shaft.

According to the present invention, since the first stage baffle has a variable control structure, the state of the residual gas molecules,
Regardless of the cryopump temperature, the first stage baffle can be controlled to an optimal opening (angle), and gas molecules can be efficiently condensed and coagulated.

[0008]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a cryopump according to a first embodiment of the present invention. As shown in FIG. 1, the cryopump according to the first embodiment of the present invention includes a first stage baffle 3 having a variable opening degree, a first stage baffle driving unit 7, and a controller for controlling the first stage baffle opening degree. 8 is provided. The first stage baffle opening controller 8 is connected to the cryopump temperature sensor 9, the vacuum gauge 10, and the first stage baffle drive unit 7. The drive shaft 11 operated by the first stage baffle drive unit 7 is connected to the first stage baffle 3, and the opening of the first stage baffle 3 changes according to the movement of the drive shaft 11.

FIGS. 2A and 2B are a plan view and a sectional view, respectively, for explaining the operation of the first embodiment. The operation of the cryopump according to the first embodiment of the present invention is shown in FIG.
As shown in (a) and (b), a controller for controlling the opening degree of the first stage baffle from the startup of the cryopump to the internal temperature of the cryopump measured by the temperature sensor 9 and the degree of vacuum measured by the vacuum gauge 11. At 8, the optimal opening degree of the first stage 3 is always determined and output to the first stage baffle drive unit 7. As shown in FIGS. 2A and 2B, the first stage baffle 3 expands and contracts in a circumferential shape by the operation of the drive shaft 11, and the opening determined by the first stage baffle opening controller 8 is controlled. Controlled every time.

FIGS. 3A and 3B are a plan view and a sectional view, respectively, of a cryopump according to a second embodiment. The cryopump according to the second embodiment of the present invention is shown in FIG.
As shown in (a) and (b), the first stage baffle 3
Of the first stage baffle opening controller 8
And a first stage baffle drive unit 7. The first stage baffle opening degree controller 8 takes in the temperature inside the cryopump from the temperature sensor 9 and outputs it to the first stage baffle drive unit 7.

Next, the operation of the second embodiment of the present invention will be described with reference to FIGS. 3 (a) and 3 (b). The operation of the cryopump according to the second embodiment of the present invention is as follows.
As shown in FIG. 3A, an angle at which the surface area of the first stage baffle 3 is maximized when viewed from the top of the cryopump until a set temperature during startup (cooling down) from a stopped state of the cryopump, Next, as shown in FIG. 3B, gas molecules having a low vapor temperature are efficiently condensed on the first stage baffle 3 before the cryopump is brought to an extremely low temperature state. Thereafter, when the internal temperature of the cryopump becomes equal to or lower than the set temperature, both the first stage baffle 3 and the second stage cryopanel 5 efficiently condense and adsorb gas molecules. In other words, this operation mainly performs the condensation in the first stage baffle 3 in the temperature range where the condensation in the second stage cryopanel 5 is possible during the startup of the cryopump. Is shortened. That is, high-speed and high-vacuum can be achieved by the switching operation of the opening degree of the first stage baffle 3.

[0013]

The first effect is that gas molecules are efficiently condensed in the pump. Thereby, high speed and high vacuum can be achieved. The reason is that the opening of the first stage baffle is always controlled to an optimum state regardless of the state of gas molecules and the state of the pump.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a cryopump according to a first embodiment of the present invention.

FIGS. 2A and 2B are a plan view and a cross-sectional view, respectively, for explaining the operation of the first embodiment.

FIGS. 3A and 3B are a plan view and a cross-sectional view, respectively, of a cryopump according to a second embodiment.

FIG. 4 is a configuration diagram of an example of a conventional cryopump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st stage cold head 2 1st stage shield 3 1st stage baffle 4 2nd stage cold head 5 2nd stage cryopanel 6 He refrigerator 7 1st stage baffle drive part 8 1st stage baffle opening degree controller 9 Temperature sensor 10 Vacuum gauge 11 Drive shaft

Claims (3)

[Claims] 1. A first stage baffle having a variable structure, a controller for controlling a first stage baffle opening connected to a temperature sensor and a vacuum gauge, and a controller connected to the first stage baffle opening control and connected via a drive shaft. A variable baffle type cryopump, comprising: a first stage baffle drive section that drives opening and closing of the first stage baffle of the variable structure. 2. The variable baffle type cryopump according to claim 1, wherein the first stage baffle performs an expansion / contraction operation in a circular shape and is controlled to an opening degree. 3. The variable baffle type cryopump according to claim 1, wherein said first stage baffle is controlled to an opening degree of two-stage switching.