WO2014041656A1

WO2014041656A1 - Vacuum processing device

Info

Publication number: WO2014041656A1
Application number: PCT/JP2012/073450
Authority: WO
Inventors: 満知明小林; 近藤　英明; 僚一磯村; 田内　勤
Original assignee: 株式会社日立ハイテクノロジーズ
Priority date: 2012-09-13
Filing date: 2012-09-13
Publication date: 2014-03-20

Abstract

In order to provide a vacuum processing device in which generation of foreign matter in the lock chamber is minimized and processing efficiency is improved, this vacuum processing device is provided with the functions of: opening a gate valve (120) that airtightly seals the interior of the lock chamber (105) linked to an atmospheric transportation unit (106) and provided so that the interior pressure can be adjusted, the sealing being conducted in a state in which the pressure in the lock chamber (105) is higher than the pressure in the atmospheric transportation unit (106) when a wafer (150) is transported to the lock chamber (105); and then introducing an inert gas from the rear part of the interior of the lock chamber (105) to the interior of the atmospheric transportation unit (106) in the direction of arrows (401).

Description

Vacuum processing equipment

The present invention relates to a vacuum processing apparatus for processing a substrate to be processed, such as a semiconductor wafer, in a processing chamber disposed inside a vacuum vessel, and includes a transfer container connected to the vacuum vessel and to which the substrate to be processed is transferred. About things.

In the above-described apparatus, particularly a vacuum processing apparatus for processing a substrate such as a semiconductor wafer (hereinafter referred to as “wafer”) which is a sample to be processed in a processing chamber disposed in a vacuum vessel and decompressed, In addition to the miniaturization and refinement of wafers, it has been demanded to improve the processing efficiency of wafers to be processed. For this reason, in recent years, a multi-chamber apparatus has been developed in which a plurality of vacuum vessels are connected to one apparatus and wafers can be processed in parallel in a plurality of processing chambers. Increasing efficiency has been done.

Further, in such an apparatus that includes a plurality of processing chambers or chambers for processing, each processing chamber or chamber has an exhaust means such as a means for supplying an electric field or a magnetic field thereto, an exhaust pump for exhausting the inside, or a processing chamber. Each processing unit is configured together with means for adjusting the supply of processing gas supplied to the inside, and this processing unit has a robot arm etc. for transporting the substrate by adjusting the internal gas and its pressure so that the pressure can be reduced. A transfer unit including a transfer chamber (transfer chamber) provided is detachably connected to a transfer unit in which a wafer is transferred and temporarily held. More specifically, the side wall of the vacuum chamber in which the processing chamber or chamber in which each processing unit is depressurized is arranged has a transport unit in which a wafer before or after processing is transported in the interior in which the pressure is reduced to the same extent. The inside of the vacuum transfer container is detachably connected so that the inside can be connected and closed.

The lock chamber, which is a part of such a device configuration, is a vacuum vessel that switches between atmospheric pressure and vacuum pressure, and the switching time between atmospheric pressure and vacuum pressure has a great influence on the productivity of the device.

Conventionally, when switching the lock chamber from vacuum pressure to atmospheric pressure, if rapid exhaust is performed, moisture in the internal gas is rapidly condensed to generate ice, and the adhered foreign matter is caused by the ice adhering to the wafer as a foreign matter. This may cause a pattern defect that cannot form an accurate electric circuit as a mask. In order to suppress the formation of such foreign matter, an inert gas such as nitrogen (N2) with sufficiently reduced moisture is supplied to the inside of the lock chamber, and gas such as air containing moisture and moisture enters inside. It has been considered to prevent this.

For example, as disclosed in Japanese Patent Application Laid-Open No. 11-063604 (Patent Document 1), the air flow from the upper side to the lower side in the room is caused by the rotation of the blower fan arranged at the upper part of the clean room to which the load lock chamber is connected. It is known that the air flow suppresses the causative substances of foreign matters such as particles from adhering to the wafer or flowing into the load lock chamber due to this air flow. Japanese Patent Application Laid-Open No. 2007-165644 (Patent Document 2) arranges a belt-shaped airflow forming device between a gate valve and a loader module at a loading / unloading port communicating the load lock module and the loader module. There has been disclosed a technique for removing foreign substances adhering to a wafer by carrying the wafer through the inside of the carry-in / out port while being exposed to a belt-like airflow formed from the top to the bottom of the carry-in / out port.

On the other hand, when exhausting the inside of the lock chamber, conventionally, it has been necessary to exhaust so that no foreign matter is formed due to the moisture, and the generation of ice due to rapid condensation of moisture in the atmosphere. Exhaust was performed at a flow rate within a range that could be prevented.

Japanese Patent Application Laid-Open No. 11-063604 JP 2007-165644 A

In the above prior art, when exhausting to depressurize the inside of the lock chamber as described above, the exhaust gas flow rate is set sufficiently high in order to suppress generation of foreign matter due to moisture icing and condensation. It takes a long time for a substrate-like sample such as a semiconductor wafer to be returned to its original position after being taken out of a cassette or the like and processed. It was hanging. For this reason, the problem that the productivity and efficiency of sample processing have been impaired has not been sufficiently considered in the above-described conventional technology.

The present invention has been made to solve the above problems. An object of the present invention is to provide a vacuum processing apparatus in which the generation of foreign matters in the lock chamber is suppressed and the processing efficiency is improved.

Moisture in the atmosphere becomes a foreign substance due to sudden exhaust when switching from vacuum pressure to atmospheric pressure in the lock chamber, and if atmospheric components are not present in the lock chamber when switching from vacuum pressure to atmospheric pressure Foreign matter due to condensation does not occur.

Therefore, in order to achieve the above object, the present invention forms a gas flow from the lock chamber side to the atmospheric transfer unit side when the lock chamber is opened, and the atmospheric gas in the atmospheric transfer unit containing moisture is locked. Reduces entry into the room.

According to the above configuration of the present invention, it is possible to prevent the gas containing moisture such as the atmosphere inside the atmospheric transfer unit from flowing into the lock chamber and exhaust the lock chamber to change from atmospheric pressure to vacuum pressure. It is possible to reduce the occurrence of foreign matter inside when the pressure is reduced. For this reason, the inside of the lock chamber can be exhausted at high speed, and the productivity and processing efficiency of the vacuum processing apparatus can be improved.

It is a top view explaining the outline of the whole structure of the vacuum processing apparatus which concerns on the Example of this invention. It is a cross-sectional view which expands and shows the vacuum conveyance chamber of the Example shown in FIG. It is a top view which expands and shows the vacuum conveyance chamber air | atmosphere conveyance unit and lock chamber of the Example shown in FIG.

Hereinafter, embodiments of the vacuum processing apparatus according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a top view for explaining an outline of the entire configuration of a vacuum processing apparatus according to an embodiment of the present invention.

A vacuum processing apparatus 100 including a vacuum processing chamber according to an embodiment of the present invention shown in FIG. 1 is roughly composed of an atmosphere side block 101 and a vacuum side block 102. The atmosphere-side block 101 is a part for carrying, storing and positioning a substrate-like sample such as a semiconductor wafer as a processing object under atmospheric pressure, and the vacuum-side block 102 is under a pressure reduced from the atmospheric pressure. A block that transports a substrate-like sample such as a wafer and performs processing in a predetermined vacuum processing chamber. The vacuum side block 102 is connected to the atmosphere side block 101 between the location of the vacuum side block 102 that performs the above-described transport and processing, and the pressure is set to atmospheric pressure with the sample inside. And a portion to be moved up and down between the vacuum pressure.

The atmosphere-side block 101 has a substantially rectangular parallelepiped housing 106 (hereinafter referred to as “atmosphere transfer unit”) having an atmosphere-side transfer robot 109 inside, and the atmosphere transfer unit 106 for preventing foreign matter from entering from the outside. Inside, the pressure is adjusted to the positive pressure side from the atmospheric pressure by the fan 301. A plurality of cassettes mounted on the front side of the atmospheric transfer unit 106 and on which a substrate-like sample (hereinafter referred to as a wafer) such as a semiconductor wafer to be processed for processing or cleaning is stored are placed thereon. The cassette stand 107 is provided.

The vacuum side block 102 is disposed between the first vacuum transfer chamber 104 and the back surface of the atmospheric transfer unit 106 of the atmospheric side block 101, and has a wafer exchanged between the atmospheric side and the vacuum side inside. One or more lock chambers 105 for exchanging pressure between atmospheric pressure and vacuum pressure are provided. The lock chamber 105 is a vacuum container whose internal space can be adjusted to the above pressure, and includes a first vacuum transfer chamber 104 on the rear side (upper side in FIG. 1) and an atmospheric transfer unit on the front side (lower side in FIG. 1). A gate valve 120 including a passage through which the wafer passes through the inside and a valve body that can be hermetically sealed by opening and closing the wafer is disposed at a position connected to each of 106. There is an airtight division between the atmosphere side and the vacuum side.

The space inside the lock chamber 105 is provided with a storage unit capable of storing and holding a plurality of wafers with a gap in the vertical direction, and the gate valve 120 is closed while the wafers are stored, so that the first It is hermetically sealed with respect to the transfer space inside the vacuum transfer chamber 104 or the atmospheric transfer unit 106. The lock chamber 105 is connected to an exhaust line including a dry pump 121, a valve 122, and an exhaust pipe 123 so that the inside can be exhausted.

Furthermore, a pressure gauge 124 capable of monitoring the pressure in the room and a purge line 125 capable of introducing a purge gas such as an inert gas into the transfer chamber while controlling the flow rate are provided. The exhaust line and the purge line 125 are controlled in response to a command from a control device (not shown), and the pressure in the lock chamber 105 is adjusted to the first vacuum by the balance between the amount rate of the introduced gas and the amount rate of the exhaust gas. The pressure is adjusted to a predetermined pressure including a value equivalent to or slightly higher than the inside of the transfer chamber 104 and a value equivalent to or slightly higher than the atmospheric pressure inside the atmospheric transfer unit 106.

The first vacuum transfer chamber 104 and the second vacuum transfer chamber 110 are units each including a vacuum vessel having a substantially rectangular shape in plan view, and these are structural differences that can be regarded as substantially the same. Are three units. Each of these vacuum transfer chambers is provided with an exhaust line constituted by a dry pump 121, a valve 122, and an exhaust pipe 123. Further, a pressure gauge 124 capable of monitoring the pressure in the vacuum transfer chamber and a purge line 125 capable of introducing a purge gas such as an inert gas into the transfer chamber while controlling the flow rate are provided. Each vacuum transfer chamber receives a command from a control device (not shown), and the exhaust line and the purge line 125 are controlled to adjust the pressure in each vacuum transfer chamber to a predetermined pressure.

The vacuum transfer intermediate chamber 111 is a vacuum container that can be depressurized to the same degree of vacuum as other vacuum transfer chambers or vacuum processing chambers. The vacuum transfer chambers are connected to each other and the internal chambers are communicated with each other. . Between the vacuum transfer chambers, there are arranged gate valves 120 that communicate with the internal chambers and open and shut off the passage through which the wafers are transferred inside, and the gate valves 120 are closed. Thus, the space between the vacuum transfer intermediate chamber 111 and the vacuum transfer chamber is hermetically sealed.

The chamber inside the vacuum transfer intermediate chamber 111 is provided with a storage unit that holds a plurality of wafers with a gap between these surfaces and holds them horizontally. When a wafer is transferred between the

transfer chambers

104 and 110, it has a function of a relay chamber that is accommodated at one end. That is, the wafers loaded by the vacuum transfer robot 108 in one vacuum transfer chamber and placed on the storage unit are unloaded by the vacuum transfer robot 108 in the other vacuum transfer chamber and connected to the vacuum transfer chamber 103. Alternatively, it is transferred to the lock chamber 105.

A vacuum transfer intermediate chamber 111 is arranged between the side walls corresponding to one surface facing the first vacuum transfer chamber 104 and the second vacuum transfer chamber 110 to connect the two. Further, the vacuum processing chamber 103 for processing the wafer is connected to the other surface by reducing the pressure inside and transferring the wafer to the inside. In this embodiment, the vacuum processing chamber 103 is an entire unit including an electric field and magnetic field generating unit configured to include a vacuum vessel, and an exhaust unit including a vacuum pump for exhausting a space to be decompressed inside the vessel. In the internal processing chamber, an etching process, an ashing process, or a process applied to another semiconductor wafer is performed. In addition, each vacuum processing chamber 103 is connected to a pipeline through which a processing gas supplied in accordance with the processing to be performed flows.

The first vacuum transfer chamber 104 is configured so that two vacuum processing chambers 103 can be connected. In this embodiment, two vacuum processing chambers are also connected, but one vacuum processing chamber 103 is connected. It may be connected. On the other hand, the second vacuum transfer chamber 111 is configured so that three vacuum processing chambers 103 can be connected, but in this embodiment, up to two vacuum processing chambers 103 are connected.

The inside of the first vacuum transfer chamber 104 and the second vacuum transfer chamber 110 is a transfer chamber, and the first vacuum transfer chamber 104 includes a lock chamber 105 and a vacuum processing chamber 103 or a vacuum under vacuum. A vacuum transfer robot 108 for transferring a wafer to / from any one of the transfer intermediate chambers 111 is disposed in the central portion of the internal space. Similarly to the second vacuum transfer chamber 110, the vacuum transfer robot 108 is arranged at the center of the inside, and the wafer is transferred between the vacuum processing chamber 103 and the vacuum transfer intermediate chamber 111.

The configuration of each of these vacuum transfer robots 108 is the same. The vacuum transfer robot 108 has a wafer placed on its arm, and in the first vacuum transfer chamber 104, the wafer is placed on the wafer stage disposed in the vacuum processing chamber 103 and either the lock chamber 105 or the vacuum transfer intermediate chamber 111. Wafer loading and unloading. Between these vacuum processing chambers 103, lock chambers 105, vacuum transfer intermediate chambers 111, first vacuum transfer chambers 104 and second vacuum transfer chambers 110, gate valves that can be closed and opened in an airtight manner, respectively. A passage communicating with 120 is provided, and this passage is opened and closed by the gate valve 120.

In addition, the vacuum processing apparatus of the present embodiment includes a plurality of gate valves 120, all of which have a structure and a configuration that are similar to each other so that they can be regarded as the same or the same. Is a unit. The gate valve 120 includes a passage having an opening that forms part of a gate through which a wafer passes and a wall surface surrounding the passage, a valve body that moves upward or downward with respect to the opening, And a drive unit such as an actuator for driving the valve body. Further, the valve body moves upward or downward to contact a wall surface of the passage around the opening and seal the seal member arranged in a ring shape so that the inside and outside of the passage are hermetically sealed. It is provided on a sheet surface having a curved surface.

In this embodiment, the wafer placed on the wafer support portion at the tip of the arm of the atmosphere-side transfer robot 109 is sucked and held on the wafer support portion by the suction device disposed on the wafer contact surface of the wafer support portion. The movement of the arm prevents the wafer from being displaced on the support portion. In particular, a configuration is provided in which the wafer is adsorbed on the contact surface by reducing the pressure by sucking ambient gas from openings arranged on the contact surface of the wafer support portion.

On the other hand, the wafer support part at the tip of the arm on which the vacuum transfer robot 108 places the wafer is not provided with suction by suction, but is provided with convex parts, protrusions, and pins on the support part that contact the wafer and suppress positional deviation. The movement of the arm prevents the wafer from shifting. In addition, in order to suppress such positional deviation, the speed of the arm operation or the rate of change (acceleration) of the speed is suppressed. As a result, compared with the atmospheric transfer robot 109 for transferring wafers of the same distance. Thus, the vacuum transfer robot 108 requires more time, and the transfer efficiency of the vacuum block 102 is lower.

Hereinafter, in this embodiment, an example in which moisture condensation in the atmosphere is reduced when the lock chamber is switched from the atmospheric pressure to the vacuum pressure will be described.

Next, the operation of processing the wafer in the vacuum processing apparatus 100 will be described below.

A plurality of wafers housed in a cassette placed on any of the cassette tables 107 are connected to the vacuum processing apparatus 100 by some communication means for adjusting the operation of the vacuum processing apparatus 100, and a control device (not shown). The processing is started in response to a command from the control unit or a command from a control device or the like of the production line where the vacuum processing apparatus 100 is installed. Upon receiving the command from the control device, the atmosphere-side transfer robot 109 takes out a specific wafer in the cassette from the cassette and transfers the taken-out wafer to the lock chamber 105.

In the lock chamber 105, since the wafer is loaded from the atmosphere side transfer robot 109, the pressure in the lock chamber 105 is increased by introducing N2. At that time, when the gate valve 120 is opened, if the pressure in the lock chamber is lower than the pressure in the atmospheric transfer unit 106, the atmosphere flows into the lock chamber, so the pressure in the lock chamber 105 is increased to a pressure higher than that in the atmospheric transfer unit 106. Then, the gate valve 120 is opened.

After the gate valve 120 is opened, the wafer is loaded into the lock chamber 105 from the atmosphere-side transfer robot 109, but there is a possibility that the atmosphere flows into the lock chamber while the atmosphere is involved by the wafer loading operation. In order to prevent such inflow of air, purging from the opening placed on the ceiling of the lock chamber 105 or on the wall surface of the side wall above the mounting position in the height direction of the wafer at the same time or just before the gate valve 120 is opened. N2 gas from line 125 is introduced.

In the present embodiment, in particular, the N2 is purged from an opening disposed near the opening on the first vacuum transfer chamber 104 side of the lock chamber 105, so that the inside of the lock chamber 105 is directed downward and toward the atmospheric transfer unit 106. N2 purge along the N2 purge direction 401 shown in FIG. Thus, by forming a gas flow in the N2 purge direction 401 from the back side of the lock chamber 105 (side where the first vacuum transfer chamber 104 is disposed) to the front side (side where the atmospheric transfer unit 106 is disposed). Further, the atmosphere containing the gas inside the atmospheric transfer unit 106, for example, the atmosphere containing water vapor, is prevented from flowing into the lock chamber 105. Note that the N2 purge from the lock chamber 105 to the atmospheric transfer unit 106 is performed from an opening disposed on the side wall surface of the lock chamber in order to prevent turbulent flow from being formed in the vicinity of the wafer accommodated therein. It is desirable.

When the pressure in the lock chamber 105 is increased from the vacuum pressure to the atmospheric pressure, N2 gas introduced from the purge line 125 and N2 gas introduced to prevent the atmosphere from flowing into the lock chamber 105 are necessary. The flow rate is different and the former is significantly larger. For this reason, the lock chamber 105 of this embodiment is provided with an air inflow line 302 for supplying a relatively small flow rate of N 2 gas separately from the purge line 125. The opening for introducing the gas may be common, but the gas source or the flow rate controller and the pipe connected to these are arranged separately.

In order to increase the pressure inside the lock chamber 105 from the vacuum pressure to the atmospheric pressure or a pressure value slightly higher than this, N 2 gas from the purge line 125 is introduced from the upper opening in the lock chamber 105. When it is detected by the output from the pressure gauge 124 that the pressure in the lock chamber 105 has increased to a predetermined value, the valve on the purge line 125 is closed and the introduction of N 2 gas from the purge line 125 is stopped. . Thereafter, the gate valve 120 on the atmosphere transfer unit 106 side of the lock chamber 105 is opened, and immediately after that, the valve on the air inflow line 302 is opened, and a relatively small flow rate of N 2 gas from the line is opened. Is supplied into the lock chamber 105 along the N2 purge direction 401 from the inlet to the atmospheric transfer unit 106. With such a configuration, when the pressure in the lock chamber 105 is increased from the vacuum pressure to the atmospheric pressure, the N2 line 125 and the N2 line 302 for preventing air inflow are used in combination to achieve both air inflow prevention and productivity improvement.

As shown in FIG. 3, when N2 purge is performed in the N2 purge direction 401 from the lock chamber 105 toward the atmospheric transfer unit 106 to prevent air flow into the lock chamber, the front and rear gate valves 120 are shielded. While the interior is partitioned, the pressure in the lock chamber 105 rises to the N2 supply pressure, and there is a concern that the lock chamber pressure becomes too high. In order to avoid the above-mentioned problem, it is necessary to stop the supply of N2 purge performed in the N2 purge direction 401 shown in FIG. 3 from the lock chamber 105 toward the atmospheric transfer unit 106 simultaneously with the timing of shielding the gate valve 120. There is.

The time lag between the gate valve 120 and the N2 supply stoppage is very small, but there is a concern of air contamination at that time. As shown in FIG. 3, the problem is that the gate valve 120 on the atmospheric transfer unit 106 side is closed in the valve body, and the wall of the upper side wall above the wafer 150 or the ceiling of the passage on the atmospheric transfer unit 106 side. The N2 gas inlet is disposed in the air unit, and N2 gas is supplied along the N2 purge direction 402 inside the atmospheric unit. In such a configuration, the N2 purge can be continuously performed regardless of the timing of shielding the gate valve 120, and the above-described purge is performed at least until the gate valve 120 is closed from the open state. The problem can be avoided.

According to the embodiment described above, when a gas containing moisture such as the atmosphere in the atmospheric transfer unit 106 flows into the lock chamber 105 and exhausts the lock chamber 105 to reduce the pressure from the atmospheric pressure to the vacuum pressure. In addition, it is possible to exhaust the inside at a high speed without generating foreign matter inside, and it is possible to provide a vacuum processing apparatus with high productivity.

In addition, this invention is not limited to the above-mentioned Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of a certain embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

101 ... Atmosphere side block,
102 ... Vacuum side block,
103 ... vacuum processing chamber,
104 ... first vacuum transfer chamber,
105 ... Lock room,
106 ... atmospheric transfer unit,
107 ... cassette stand,
108 ... Vacuum transfer robot,
109 ... atmospheric transfer robot,
110 ... second vacuum transfer chamber,
111 ... Vacuum transfer intermediate chamber,
120 ... Gate valve,
121 ... Dry pump,
122 ... Valve,
123 ... Exhaust piping,
124 ... Pressure gauge,
125 ... Purge line,
150 ... wafer,
301 ... Fan,
302 ... Air inflow line,
401 ... N2 purge direction,
402 ... N2 purge direction.

Claims

An atmospheric transfer unit having a table on which a cassette containing wafers is placed on the front surface, a vacuum transfer chamber in which the wafer is transferred inside the vacuum transfer unit disposed at the rear of the atmospheric transfer unit, and a predetermined vacuum pressure; A vacuum processing chamber having a processing chamber for processing the wafer, which is connected to the vacuum transfer chamber and disposed in the reduced pressure, and is disposed between the vacuum transfer chamber and the atmospheric transfer unit. And a lock chamber that is connected to the inside and can be variably adjusted between atmospheric pressure and the vacuum pressure, and is disposed between the lock chamber and the atmospheric transfer unit and between the vacuum transfer chamber and closed. A gate valve for hermetically sealing the lock chamber, wherein the lock chamber pressure is higher than the pressure in the atmospheric transfer unit when the wafer is loaded into the lock chamber. Opening the gate valve in state, the vacuum processing apparatus characterized by having a function of introducing toward the inside of the atmospheric transfer unit with an inert gas after opening the gate valve from the rear of the lock chamber.
2. The vacuum processing apparatus according to claim 1, wherein a large flow rate supply line that supplies gas to raise the lock chamber pressure from the vacuum pressure to atmospheric pressure, and the inert gas after the gate valve is opened. 3. And a small flow line for supplying a vacuum.
3. The vacuum processing apparatus according to claim 1, wherein the large flow rate line is used until the pressure in the lock chamber is increased to an atmospheric pressure or a value slightly higher than the atmospheric pressure, and the small valve is opened after the gate valve is opened. A vacuum processing apparatus for introducing the inert gas from a flow line into the lock chamber.
4. The vacuum processing apparatus according to claim 1, wherein the inert gas is directed toward an inside of the atmospheric transfer unit from an opening disposed at a rear upper portion of the lock chamber after the gate valve is opened. A vacuum processing apparatus that is characterized by introducing the above.