JP2656199B2 - Opening method of vacuum chamber and PVD apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering apparatus and other PVD apparatuses having a vacuum chamber, and more particularly to a means for opening a vacuum chamber to the atmosphere.

[0002]

2. Description of the Related Art Vacuum devices are widely used in industrial fields such as semiconductors and optics. As an example of using an apparatus having such a vacuum process, PVD (physical vapor) is used.
deposition) method. The PVD method is a technique for forming a thin film, mainly a method of physically depositing a metal, and the sputtering method, which is one of the forming methods, is based on the principle of accelerating Ar ^{+ and the} like in a vacuum by a discharge method in principle. This is to collide with an electrode (target) maintained at a negative potential. According to this method, the electrode material is desorbed from the surface receiving the Ar ⁺ energy (this is called a sputtering phenomenon), and the protruding material is deposited on another substrate to form a thin film.

[0003] The above-described sputtering apparatus requires a vacuum chamber for converting thin film materials into high-energy ions in a vacuum. In order to evacuate the gas in the vacuum chamber, a vacuum evacuation device is required. For this vacuum evacuation device, a cryopump or a trap turbo pump is conventionally used. An example of a cryopump system using a helium gas refrigerator will be described with reference to FIG. A cryo pump 3 is connected to the vacuum chamber 1 via a pipe 8 having a main valve (high vacuum valve) 2. The cryopump 3 is connected to a rotary pump (mechanical pump) 5 via a cryov valve 4. A pipe 7 having a chamber rough valve 6 is drawn out of the vacuum chamber 1 separately from the above system. The other end of the pipe 7 is connected to a pipe 8 a connecting the cryo-rough valve 4 and the rotary pump 5. It is connected. Further, another line 9 is led out of the vacuum chamber 1 via a chamber vent valve 10 on the way.

FIG. 5 shows an example of the configuration of the cryopump 3. In the figure, a rotary shaft 11 connected to a small helium gas refrigerator (not shown) has entered into a pump case 12, and a cold blade 13 is provided at a tip of the shaft. A baffle 14 is provided at an intake port of the pump case 12, and a pipe 8 is connected to the intake port.

In the cryopump 3 described above, the baffle 1
4. Among the gas molecules which are cooled to a very low temperature by the cold blades 13 and the like and which enter from the gas phase through the pipe 8, water vapor or a gas having a higher vapor pressure than the vapor
4 and the like. Lower gases such as nitrogen, oxygen and argon are adhered to the cold blade 13,
Gas with lower vapor pressure is cold panel (not shown)
And are respectively captured by the adsorbent.

In order to evacuate the cryopump 3 using the vacuum evacuation system shown in FIG. 4, first, the chamber vent valve 10, the main valve 2, and the cryoplav valve 4 are closed, and the chamber rough valve 6 is opened. The rotary pump 5 is driven to rough the inside of the vacuum chamber 1. Next, the chamber rough valve 6 is closed, and the cryopump 3 is driven to make the inside of the vacuum chamber 1 high vacuum. In the above-described vacuum evacuation system, the main valve 2 and the cryo-rough valve 4 are absolutely necessary in terms of the capacity of the cryopump 3, and the chamber rough valve 6 is also necessary to roughly exhaust the inside of the vacuum chamber 1. Further, the chamber vent valve 10 is required regardless of the type of the vacuum pump.

[0007]

Since the cryopump is a built-in pump, the rise time from the time when the switch is turned on until the start of operation (the time when the cryopump is cooled to a predetermined temperature).
In addition, the fall time (time for raising the temperature to a predetermined temperature) from the switch OFF to the stoppage of the operation takes 1 hour to 2 hours. During that time, when the vacuum chamber is in communication with the cryopump, the work is performed by opening to the atmosphere. Can not do. Therefore, a main valve 2 is always required between the vacuum chamber and the cryopump.

A high vacuum bellows valve or the like is used for the main valve 2. However, the pressure difference between the high vacuum side and the atmospheric pressure side is large, and the main valve structure is generally not complicated because it needs to be hermetically sealed. Not get. However, when the structure of the main valve becomes complicated, the surface area of each member constituting the valve increases accordingly, and since the valve exists in a high vacuum, it causes dust generation due to dust adhering to the surface of each member. There is a problem that a release gas is generated from the material of each member, which flows into the vacuum chamber, and prevents a high vacuum inside the vacuum chamber. In other words, it is most ideal that there is no main valve between the vacuum chamber and the cryopump in order to make the inside of the vacuum chamber a high vacuum, but in the vacuum evacuation system using the cryopump shown in FIG. The valve cannot be removed.

On the other hand, instead of a cryopump, a trap panel is provided at a pump suction port, the trap panel is cooled, water molecules are attached to the trap panel, and a turbo molecular pump with a trap panel for removing the water molecules ( (Not shown) may be used. However, a turbo-molecular pump with this trap panel (hereinafter also referred to as a turbo pump)
However, it takes about one hour to vaporize and remove the water molecules attached to the trap and start operating again. In other words, to vent the inside of the vacuum chamber to atmospheric pressure, the trap panel is operated at a steady temperature (that is, as in the case of a cryopump).
At a temperature at which water molecules can be adsorbed, the temperature must be from about 100K to room temperature (for example, 300K), but it takes about 1 hour.

Therefore, even when a turbo pump with a trap panel is used, a main valve is required between the vacuum chamber and the turbo pump with a trap panel, and dust generation and discharge from the main valve are required as in the case of a cryopump. Problems such as gas occur.

The present invention provides a method for opening a vacuum chamber which can remove a main valve which has been conventionally used when venting or opening the vacuum chamber to the atmosphere, and a PVD apparatus suitable for the method. The purpose is to:

[0012]

According to the first aspect of the present invention, there is provided a PVD evacuated by a turbo-molecular pump having a trap panel at an intake port for freeze-aggregating water molecules.
In a method of opening a vacuum chamber of the apparatus to the atmosphere, the vacuum chamber and the turbo-molecular pump are maintained in communication with each other, and while the turbo-molecular pump is driven, the trap panel is kept at about room temperature. To evaporate water molecules freeze-agglomerated in the trap panel, stop the turbo-molecular pump, close the exhaust port side of the turbo-molecular pump, and open the vacuum chamber to the atmosphere. It is characterized by. According to a second aspect of the present invention, there is provided a PVD apparatus having a vacuum chamber, wherein (a) a turbo-molecular pump and (b) a trap panel disposed at an intake port of the turbo-molecular pump for freeze-aggregating water molecules. And (c) a vacuum exhaust device having a heating device disposed near the trap panel and heating the trap panel to about room temperature, and the vacuum chamber evacuated by the vacuum exhaust device to the atmosphere. When the trap panel is opened, the trap panel is heated to about room temperature while the vacuum chamber and the evacuation device are maintained in communication with each other, and the turbo molecular pump is driven. The water molecules freeze-aggregated on the panel are evaporated, the evacuation device is stopped, the evacuation port side of the evacuation device is closed, and the vacuum chamber is It is characterized in that so as to open to the atmosphere.

[0013]

According to the above construction, water molecules adhering to the trap panel of the turbo pump with the trap panel can be forcibly vaporized in a short time by the heating device, and the turbo pump can be operated to quickly exhaust the water molecules.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 shows a turbo pump 15 with a trap panel according to an embodiment, and FIG. 3 shows a vacuum evacuation system using the pump 15. In FIG. 3, the vacuum chamber 1 and the turbo pump 15 with a trap panel are directly connected via a pipe 16. The turbo pump 15 with a trap panel is connected to the rotary pump 5 via an auxiliary valve 17. A pipe 9 is led out of the vacuum chamber 1 via a chamber vent valve 10.

The turbo pump 15 with a trap panel used in the above-described evacuation system is configured as shown in FIG. FIG. 1B is a cutaway side view, and FIG. 1A is a vertical sectional front view of the trap panel. In each of the drawings, an impeller 20 integral with the main shaft 19 is provided in the pump case 18, an intake port 21 is provided at one end of the pump case 18, and an exhaust port is provided at the other end. ing. A flange 22 for connecting to the pipeline 16 is provided at a peripheral portion of the intake port 21.

A trap panel 23 is provided inside the intake port 21 of the pump case 18. The trap panel 23 has an annular trap panel 24 as shown in an enlarged view in FIG. 2, and has an inner peripheral surface provided with support members arranged in a substantially cross shape as viewed from the front so as to intersect at the center of the intake port 21. The outer end of the frame 25 is fixed.

A central trap panel 26 is provided on a central side surface of the support frame 25. The center trap panel 26 has the same disk shape as the cross-sectional shape of the main shaft 19 of the impeller 20 and is provided with substantially the same size as the diameter of the main shaft 19. The central trap panel 26 and the main shaft 19 are provided on the same axis. The annular trap panel 24, the support frame 25, and the central trap panel 26 are all cold panels, which can trap only water molecules, and can reduce the evacuation time by rapid evacuation of water molecules. Things. Further, other gas molecules are forcibly exhausted by the impeller 20 of the turbo pump.

In the present embodiment, a heating device 27 composed of, for example, a heating coil is disposed between the trap panel 23 and the intake port 21 of the pump case 18. The heating device 27 is for quickly and forcibly evaporating water molecules adsorbed on the trap panel 23 in a short time. Therefore, the specific configuration and the arrangement position of the heating device 27 are not limited to the illustrated example.

A heat conductor 28 made of copper or the like having a high heat conductivity is connected to the annular trap panel 24, and an end of the heat conductor 28 is connected to a freezing section 30 of a refrigerator 29. ing. Then, the low-temperature heat source generated in the refrigerator 29 is guided to the trap panel 23 by the heat conductor 28,
Cool it. The cooling temperature of the trap panel 23 is determined by the balance between the heat load on the trap panel 23 and the cooling capacity. In addition, the refrigerator 29 is a pump case 1
The cooling unit 30 of the refrigerator 29 and the heat conductor 28 are accommodated in the holding case 31.

The operation of this embodiment will be described.

In order to evacuate using the evacuation system shown in FIG. 3, the chamber vent valve 10 is closed and the auxiliary valve 17 is used.
Is opened, the rotary pump 5 is driven, and the inside of the vacuum chamber 1 is roughly evacuated. At the same time, the turbo pump 15 with the trap panel and the refrigerator 29 of the trap panel 23
Drive. The turbo pump is turned into a steady state in a few minutes, exhausts the inside of the vacuum chamber 1, and the trap panel 23 reaches a steady temperature in about one hour, so that the inside of the vacuum chamber 1 can be made high vacuum.

When the turbo pump 15 with a trap panel is driven, the gas molecules in the vacuum chamber 1 are sucked into the pump case 18 from the suction port 21 by the rotation of the impeller 20 as shown in FIG. It is exhausted from. At this time, of the gas molecules, water molecules occupying a prominent portion are freeze-agglomerated by the annular trap panel 24, the support frame 25, and the central trap panel 26 at the inlet of the pump case 18, so that efficient exhaust is performed.

After the operation under vacuum in the vacuum chamber 1 is completed, for example, in order to exclude the inside of the vacuum chamber 1,
The chamber vent valve 10 may be opened to vent the vacuum chamber 1 to atmospheric pressure. In this case, turbo pump 1
5 is a steady temperature (for example, 100K).
And the temperature must be normal temperature (300 K), and when communicating with the atmosphere at a steady temperature, water molecules adsorbed as ice on the trap panel 23 rapidly vaporize or liquefy and flow back to the vacuum chamber 1. Such a trouble occurs. Therefore, conventionally, it took about one hour to raise the temperature of the trap panel 23 from the steady temperature to the normal temperature. However, according to the present embodiment, the heating device 27 is provided near the intake port 21 of the turbo pump 15. Therefore, the temperature of the trap panel 23 can be raised from a steady temperature to a normal temperature in several minutes. When the temperature of the trap panel 23 reaches room temperature, the auxiliary valve 17 is closed and the turbo pump 15 is turned off.
Is closed, the chamber vent valve 10 is opened, and the vacuum chamber 1 is vented to atmospheric pressure.

In the case of this embodiment, it takes about 10 minutes as described above to bring the vacuum chamber 1 to a state where it can be vented. With a main valve as in the past, this waiting time of 10 minutes is not necessary. However, by waiting for this 10 minutes, the main valve can be omitted, the configuration is simplified, and the main valve is omitted. The benefits are greater. In particular, if the vacuum performance, particles, and the like are included, the effect of omitting the main valve cannot be measured.

The structure of each part of this embodiment may be changed in design as needed.

[0027]

As described above, according to the vacuum evacuation apparatus of the present invention, gas molecules can be forcibly exhausted by the turbo molecular pump, and the trap panel occupies a prominent portion of the gas molecules to be exhausted. Water molecules can be exhausted. In addition, the heating device provided at the intake port allows the water molecules condensed on the trap panel to be quickly vaporized and exhausted, so that the start-up and shut-down time of the turbo molecular pump can be shortened, and the working efficiency can be improved. it can. In addition, as the turbo molecular pump is started up and the down time is shortened, the turbo molecular pump can be directly connected to the vacuum chamber, and there is no problem even if the conventional main valve is omitted. Therefore, the structure can be simplified. Further, by eliminating the need for the main valve, it is possible to reduce dust generation and discharge gas generated by the main valve in a vacuum, and clean vacuum exhaust of the vacuum chamber can be obtained.
Further, since the main valve is eliminated, the conductance of the exhaust port portion is increased, so that the vacuum performance is improved.

[Brief description of the drawings]

FIG. 1 (a) is a longitudinal sectional front view of a trap panel of FIG. 1 (b), and FIG. 1 (b) is a cutaway side view of a turbo pump with a trap panel according to an embodiment.

FIG. 2A is an enlarged perspective view of the trap panel, and FIG. 2B is a cross-sectional view taken along the line II-II of FIG.

FIG. 3 is an explanatory diagram of an evacuation system according to the embodiment.

FIG. 4 is an explanatory diagram of a vacuum evacuation system using a conventional cryopump.

FIG. 5 is an explanatory sectional view of a cryopump.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vacuum chamber, 2 ... Main valve, 5 ... Rotary pump, 10 ... Chamber vent valve, 15 ... Turbo pump with trap panel, 16 ... Pipe line, 17 ... Auxiliary valve, 18 ... Pump case, 20 ... Impeller, 23 ... trap panel, 24 ... annular trap panel, 25 ... support frame, 26 ... central trap panel, 27 ... heating device,
28: heat conductor, 29: refrigerator.

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-5792 (JP, A) JP-A-4-175475 (JP, A) JP-A-2-294575 (JP, A)

Claims (2)

(57) [Claims] 1. A method for opening a vacuum chamber of a PVD apparatus evacuated by a turbo molecular pump having a trap panel for freezing and aggregating water molecules at an intake port to the atmosphere, wherein the vacuum chamber and the turbo molecular pump are opened. With the turbo-molecular pump being driven, the trap panel is heated to about room temperature to evaporate water molecules frozen and aggregated in the trap panel, A method for opening a vacuum chamber, comprising: stopping a pump; closing an exhaust port side of the turbo-molecular pump; and opening the vacuum chamber to the atmosphere. 2. A PVD apparatus having a vacuum chamber, comprising: (a) a turbo molecular pump; (b) a trap panel disposed at an inlet of the turbo molecular pump for freeze-aggregating water molecules; Providing a vacuum exhaust device having a heating device disposed near the trap panel and heating the trap panel to about room temperature, wherein the vacuum chamber evacuated by the vacuum exhaust device is opened to the atmosphere. In the state where the vacuum chamber and the vacuum exhaust device are kept in communication with each other, and the turbo molecular pump is driven, the trap panel is heated to about room temperature by the heating device, and the trap panel is heated. The water molecules freeze-agglomerated are evaporated, the evacuation device is stopped, and the evacuation port side of the evacuation device is closed. PVD apparatus being characterized in that so as to open to the atmosphere.