JPH08210252A - Cryopump and manufacturing device of semiconductor - Google Patents

Abstract

PURPOSE: To conduct diversified control of vacuum exhaust performance of a plurality of gas species. CONSTITUTION: A conductance regulating valve 5 to selectively vacuum exhaust capacity on the secondary stage 6 side independently from a primary stage 3 through control of conductance between the primary stage 3 and the secondary stage 6 is located between the secondary stage 6 at which a cooling temperature is further lower and the primary stage 3 at which a cooling temperature is further higher and which is connected to the treatment chamber 1 of equipment to be exhausted through a main valve 2. By controlling the opening of the valve body 5b of the conductance regulating valve 5 through the valve drive shaft 7a of a conductance regulating valve drive part 7 from the outside, exhaust (pressure control) capacity of a gas specie, such as process gas, by the secondary stage 6 is arbitrarily controlled without operating a main valve 2 in such a state to maintain capacity to adsorb and exhaust and remove a moisture content having a high steam pressure by the primary stage 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryopump and a semiconductor manufacturing technique, and more particularly to a technique effectively applied to a vacuum pumping technique which requires various control of vacuum pumping ability of a plurality of gas species. .

[0002]

2. Description of the Related Art For example, in a semiconductor device manufacturing process, there are many facilities for evacuating a processing space of a semiconductor wafer to a high degree of vacuum, such as an etching, sputter film forming, and CVD film forming device. As a vacuum exhaust device used for such an application, a cryopump having an advantage of maintaining cleanliness of an exhaust space is used.

For example, the Japan Society of Mechanical Engineers, 199
As described in the literature such as the new edition 5 prints issued on September 30, 1st, "Mechanical Engineering Handbook" B5 edition-P160, Fig. 378, etc., the cryopump has a one-stage stage and two stages provided inside. The cold panel of each stage is cooled to an extremely low temperature to condense or adsorb gas molecules to obtain a high vacuum pressure.

In the first stage, water is mainly condensed and adsorbed by a cooling temperature of, for example, about 100 K, and in the second stage, process gas (Ar or nitrogen in the case of a sputtering apparatus is mainly used by a cooling temperature of, for example, about 20 K). Etc.) is condensed and adsorbed to obtain a vacuum pressure.

Taking a sputtering apparatus as an example, after high vacuum exhaustion (reducing residual gas components in the vacuum processing chamber), a process gas (inert gas such as Ar gas) is introduced to increase the pressure in the vacuum processing chamber. A plasma discharge is being generated. At this time, in order to increase the pressure in the vacuum processing chamber, the opening degree of the main valve between the cryopump and the vacuum processing chamber is adjusted,
The vacuum pumping capacity of the cryopump is suppressed and the pressure is raised to a level at which discharge is possible.

[0006]

However, in the conventional vacuum pressure adjustment by adjusting the opening degree of the main valve as described above, the vacuum exhaust capability of both the first stage and the second stage is reduced. Therefore, for example, in the case of a sputtering device,
Exhaust of not only the process gas but also the moisture (water vapor), which has the most adverse effect on the film formation, is suppressed at the same time, and the remaining water vapor in the vacuum processing chamber deteriorates the quality of the sputtered thin film. There are concerns about such problems.

An object of the present invention is to provide a cryopump capable of variously controlling the vacuum evacuation capability of a plurality of gas species.

Another object of the present invention is to variously control the evacuation capability of a plurality of gas species in a semiconductor manufacturing apparatus that requires evacuation.

Still another object of the present invention is to improve the yield of semiconductor devices manufactured by the semiconductor manufacturing apparatus.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0011]

Of the inventions disclosed in the present application, a representative one will be briefly described below.
It is as follows.

After the conventional cryopump has been used to evacuate to an arbitrary ultimate vacuum pressure and then to raise the pressure to the processing pressure, the opening of the main valve between the cryopump and the processing chamber is reduced to reduce the processing pressure. Was getting

In this method, the vacuum evacuation capacity of the first and second stages is both reduced, and especially when a film is formed by the sputtering method, the decrease in the water evacuation capacity affects the quality of the film formed. This will reduce the reliability of the product.

Therefore, in the present invention, a mechanism for controlling the conductance between the two stages is arranged between the two stages so that only the vacuum evacuation capability of the second stage can be controlled without lowering the evacuation capability of the first stage. To do.

As a mechanism for controlling conductance,
For example, a variable conductance control valve arranged above the second stage can be used.

[0016]

In the present invention, a variable conductance valve is attached between the first stage and the second stage in the cryopump, for example. At the time of normal vacuum exhaust (obtaining the ultimate vacuum pressure), the variable conductance valve is fully opened so that the vacuum exhaust capability of the first and second stages can be fully exhibited.

Next, for example, when performing a sputtering process, the opening of the variable conductance control valve is narrowed in order to control the amount of gas that is evacuated (condensed or adsorbed) in the two-stage stage, and an arbitrary processing vacuum pressure is set. To get

As a result, 1 connected to the vacuum processing chamber side
Moisture that is evacuated in the multi-stage can arbitrarily change the vacuum pressure of the process gas for sputtering without lowering its evacuation capability, and is caused by, for example, residual moisture in the vacuum processing chamber. As a result, the quality of the thin film formed by sputtering can be prevented, and the yield of the semiconductor device including the sputtering film forming step as a part of the manufacturing process can be improved.

[0019]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an example of a cryopump which is an embodiment of the present invention, and FIG. 2 is a conceptual view showing an example of a semiconductor manufacturing apparatus equipped with this cryopump as a vacuum exhaust device. is there. In this embodiment, as an example of a semiconductor manufacturing apparatus, a case of applying it to a sputtering film forming apparatus will be described.

The cryopump of this embodiment has a structure as shown in FIG. In FIG. 1, reference numeral 1 is a processing chamber as an equipment to be evacuated, and is, for example, a sputtering film forming apparatus described later. 2 is a main valve that separates the cryopump from the processing chamber, 3 is a one-stage stage that evacuates water having a relatively high vapor pressure, and 6 is a relatively low vapor pressure A
This is a two-stage stage that evacuates the processing gas such as r.

The two-stage stage 6 is connected to a refrigerator 8 capable of generating an extremely low temperature by using, for example, helium gas as a working fluid. The first stage 3 is connected to the refrigerator 8 via the heat conducting member 3 a and the second stage 6.

The cooling temperatures of both are 1 on the side close to the processing chamber 1.
The stage 3 is, for example, 80K, and the second stage 6 far from the processing chamber 1 is, for example, 15K.

In this case, by controlling the conductance between the second stage 6 and the first stage 3 by controlling the conductance between the first stage 3 and the second stage 6, the second stage 6 is independent of the second stage 6. A conductance adjustment valve 5 for selectively adjusting the vacuum exhaust capacity on the stage 6 side is provided. This conductance adjustment valve 5
It is held by a heat insulating material 4 which insulates the conductance adjusting valve 5 and the cryopump inner surface cooled to an extremely low temperature.

The conductance adjusting valve 5 has a plurality of swing shafts 5 parallel to each other at a position surrounding the heat conducting member 3a.
It is composed of a plurality of valve elements 5b supported and arranged on each of a.

Outside the conductance adjusting valve 5,
A conductance adjustment valve drive unit 7 for controlling the opening degree by collectively swinging these valve bodies 5b from the outside.
Is provided. That is, the conductance adjustment valve drive unit 7 is inserted into the conductance adjustment valve 5, engages with the plurality of valve bodies 5b and swings around the swing shaft 5a, and the valve body drive shaft 7a. The operation shaft 7a includes a bellows 7b that airtightly covers the outer end portion of the drive shaft 7a to keep the insertion portion of the valve body drive shaft 7a with respect to the cryopump body airtight, and an operation knob 7c.

On the other hand, the sputtering film forming apparatus of this embodiment is provided with a processing chamber 1 connected to a cryopump via a main valve 2 as illustrated in FIG. Processing room 1
A process gas 14a made of, for example, an inert gas such as argon gas is supplied to the via a gas supply pipe 14. Inside the processing chamber 1, a sputtering stage 11 on which a substrate 10 such as a semiconductor wafer is placed, and a sputtering stage 11 arranged so as to face the sputtering stage 11,
A target 12 made of a desired substance forming a thin film to be formed is provided. A glow discharge is generated between the sputtering stage 11 and the target 12 by applying a voltage between the sputtering stage 11 and the target 12, and a plasma 14b of the process gas 14a is formed between the target 12 and the substrate 10. The power supply 13 is connected. The ions of the process gas 14a contained in the plasma 14b have a function of bombarding the target 12 and knocking out the atoms of the substance forming the target 12 to deposit them on the substrate 10, thereby forming a film by sputtering. To do.

An example of the operation of this embodiment will be described below.

First, with the gas supply pipe 14 closed, the main valve 2 and the conductance adjusting valve 5
Fully open, and the inside of the processing chamber 1 is, for example, 10 ⁻⁸ to
A cleaning operation of evacuating to a high vacuum of about 10 ⁻⁹ Torr is performed. This is to remove as much water as possible that is harmful to the sputtering film formation.

Next, the operation of introducing the process gas 14a into the process chamber 1 by opening the gas supply pipe 14 is started. For example, when performing the sputtering process, the pressure of the process gas 14a is used to form the plasma 14b. Is required to be increased to, for example, about 10 ⁻³ Torr, it is necessary to control the vacuum pumping capacity by the cryopump.

Conventionally, the pressure in the processing chamber 1 was controlled by controlling the opening and closing of the main valve 2. However, in that case, as described above, the removal of water vapor having a high vapor pressure by the first stage 3 is performed. The action is also impaired.

Therefore, in the case of the present embodiment, the opening of the conductance adjusting valve 5 is controlled via the conductance adjusting valve drive unit 7 while the main valve 2 is kept open, and the vacuum exhaust (condensing) is performed in the second stage 6. Or the amount of process gas to be adsorbed) is adjusted to obtain an arbitrary processing vacuum pressure.

As a result, the capability of removing water and the like in the processing chamber 1 is reduced while maintaining the vacuum exhaust capability in the first stage 3 for capturing water vapor and the like having a relatively high cooling temperature and a high vapor pressure. Without controlling the exhaust gas capacity of the process gas 14a having a lower vapor pressure in the second stage 6 having a lower cooling temperature, the pressure of the process gas 14a is optionally set to the vacuum pressure for sputtering film formation. Therefore, it is possible to reliably prevent the film quality of the thin film formed by sputtering on the substrate 10 from being deteriorated by residual moisture in the processing chamber 1. As a result,
It is possible to improve the quality and yield of semiconductor devices formed on the substrate 10.

In the above description, for the sake of simplicity, the cryopump is directly connected to the sputtering film forming apparatus to evacuate the vacuum. However, although the ultimate vacuum is lower than that of the cryopump, the unit time is reduced. The present invention also includes a configuration in which a preliminary evacuation operation or the like is performed by interposing a vacuum pump or the like having a large exhaust capacity per hit.

Although the invention made by the present inventor has been specifically described based on the embodiments, the invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, the semiconductor manufacturing apparatus to which the cryopump is connected is not limited to the sputtering film forming apparatus, but is widely applied to the etching apparatus, the CVD apparatus, the ion implantation apparatus, and the like, which require high vacuum control. be able to.

[0037]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It is as follows.

That is, according to the cryopump of the present invention, it is possible to obtain the effect that the vacuum pumping ability of a plurality of gas species can be variously controlled.

According to the semiconductor manufacturing apparatus of the present invention,
In a semiconductor manufacturing apparatus that requires vacuum exhaust, it is possible to variously control the vacuum exhaust capability of a plurality of gas species,
The effect is obtained.

According to the semiconductor manufacturing apparatus of the present invention,
The yield of semiconductor devices manufactured by the semiconductor manufacturing apparatus can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a cryopump that is an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing an example of a semiconductor manufacturing apparatus equipped with a cryopump as an evacuation device which is an embodiment of the present invention.

[Explanation of symbols]

 1 Processing Chamber 2 Main Valve 3 1st Stage (1st Stage) 3a Heat Conducting Member 4 Heat Insulating Material 5 Conductance Control Valve (Valve Mechanism) 5a Swing Shaft 5b Valve Body 6 2nd Stage (2nd Stage) 7 Conductance Adjustment valve drive unit (valve mechanism) 7a Valve body drive shaft 7b Bellows 7c Operation knob 8 Refrigerator (cold heat source) 10 Substrate 11 Sputter stage 12 Target 13 Power supply 14 Gas supply pipe 14a Process gas 14b Plasma

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Koichi Koyanagi, 3-3 Fujibashi, Ome, Tokyo 2-3 Hitachi Hitachi Electronics Co., Ltd. (72) Inventor Jiro Sakaguchi 3-3, Fujibashi, Ome, Tokyo 2 Hitachi Inside Tokyo Electronics Co., Ltd. (72) Inventor Tadao Sakamoto 3-3 Fujibashi, Ome City, Tokyo 2 Inside Hitachi Tokyo Electronics Co., Ltd.

Claims (6)

[Claims] 1. At least two first cooling devices having different cooling temperatures
And a second stage, a cold heat source for cooling the first and second stages, and a conductance arranged between the first and second stages and between the first and second stages. A cryopump that includes a valve mechanism that controls the cryopump. 2. The first stage side is connected to equipment to be exhausted, and the second stage is cooled to a temperature lower than that of the first stage, and the conductance of the valve mechanism is reduced. The cryopump according to claim 1, wherein the exhaust capacity for a plurality of gas species having different vapor pressures is independently controlled by the control. 3. The equipment to be evacuated is a sputtering film-forming apparatus, wherein an inert gas forming plasma for sputtering is adsorbed and evacuated in the second stage, and water vapor in the sputtering atmosphere is evacuated in the first stage. 3. The cryopump according to claim 2, wherein the exhaust capability of the inert gas is controlled while the exhaust capability of the water vapor is maintained by adsorbing and exhausting and controlling the conductance by the valve mechanism. 4. A semiconductor manufacturing apparatus comprising: a vacuum processing chamber in which a semiconductor wafer is housed; and a cryopump for exhausting the vacuum processing chamber, wherein the cryopump has at least two first and second cooling temperatures different from each other. A second stage, a cold heat source that cools the first and second stages, and a conductance between the first and second stages that is disposed between the first and second stages. A semiconductor manufacturing apparatus comprising a valve mechanism for controlling. 5. The second stage is connected to the vacuum processing chamber while the second stage is connected to the first stage.
The stage is cooled to a temperature lower than that of the stage, and the conductance is controlled by the valve mechanism to independently control the exhaust capacity for a plurality of gas species having different vapor pressures in the vacuum processing chamber. Item 4. The semiconductor manufacturing apparatus according to item 4. 6. The semiconductor manufacturing apparatus is a sputtering film forming apparatus, wherein an inert gas forming plasma for sputtering is adsorbed and exhausted in the second stage, and water vapor in the sputtering atmosphere is discharged in the first stage. 6. The semiconductor manufacturing apparatus according to claim 5, wherein the exhaust capability of the inert gas is controlled while the exhaust capability of the water vapor is maintained by adsorbing and exhausting, and controlling the conductance by the valve mechanism.