JP2017022215A - Vacuum processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum processing apparatus capable of improving yield of a semiconductor device and improving throughput compatibly by reducing influences caused by dew condensation or fine particles generated by rapid pressure reduction within a load lock that switches a vacuum atmosphere and an air atmosphere.SOLUTION: The vacuum processing apparatus comprises lock chambers (105-1 and 105-2) in which a wafer is accommodated and which is capable of increasing/decreasing a pressure between a reduced pressure and an atmospheric pressure by exhausting the inside and supplying a gas. The gas within the lock chamber is sucked into a storage part 211 that is disposed on an exhaust path 204 of the lock chamber, the pressure within the lock chamber is reduced to a predetermined vacuum degree, the gas within the lock chamber is then exhausted through the storage part to the outside, and the pressure in the lock chamber is reduced.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vacuum processing apparatus.

  2. Description of the Related Art Conventionally, a vacuum processing apparatus that processes a wafer in a vacuum vessel, particularly a vacuum processing apparatus that includes a load lock that adjusts the pressure between the atmosphere and vacuum of the wafer has been known as follows. That is, Patent Document 1 shows that in a chamber that switches between a vacuum atmosphere and an air atmosphere, when the inside of the chamber is evacuated, the valve is slowly opened to suppress sudden decompression in the chamber.

  Further, Patent Document 2 is provided with an exhaust line in which a plurality of pressure reserve tanks are connected in series, and separately provided with an exhaust line connected only via a load lock and a vacuum pump. It has been shown that the evacuation operation in the load lock can be speeded up by evacuating the volume several times.

JP-A-5-237361 JP-A-9-306972

  By the way, in a vacuum processing apparatus such as a plasma processing apparatus, a multi-chamber is progressing. The multi-chamber is a system in which a plurality of processing chambers (chambers) are connected to a set of transfer systems for transferring wafers. The advantage of using a multi-chamber is that, for example, the number of wafers that can be processed per manufacturing apparatus increases. Therefore, when the number of processing chambers connected to the transfer chamber is increased from one to 2 → 3 → 4, the number of wafers processed per unit time is also double → 3 × → 4 compared to the case of one processing chamber. It is desirable to double. However, in reality, the number of processable sheets per unit time does not increase as expected even if the number of processing chambers is increased. One factor is that it is difficult to improve the load lock throughput.

  In the load lock, evacuation when reducing pressure from atmospheric pressure to vacuum and purging (supplying) when pressurizing from vacuum to the atmosphere are performed. As for evacuation, since the gas temperature rapidly decreases in the early stage of the exhaust stage, the residual gas existing in the load lock is condensed, and condensation and liquid fine particles are generated. In particular, since a reaction product is generated from a wafer immediately after plasma processing, condensation and liquid fine particles are more likely to occur. Since such condensation and fine particles reduce the yield of semiconductor devices, it is necessary to reduce foreign matters in the load lock.

  The above prior art has a problem because the following points are not sufficiently considered. That is, Patent Document 1 describes a method for suppressing sudden decompression, but does not consider the point of throughput.

  Further, Patent Document 2 describes a method for improving the throughput, but does not take into consideration that dew condensation due to rapid decompression or fine particles reduce the yield of semiconductor devices.

  The object of the present invention is made in view of these problems, and reduces the influence of condensation and fine particles generated by sudden decompression in a load lock that switches between a vacuum atmosphere and an air atmosphere, thereby improving the yield of semiconductor devices and throughput. An object of the present invention is to provide a vacuum processing apparatus that can achieve both improvement.

As an embodiment for achieving the above object, a processing unit for processing a wafer to be processed, which is disposed in a processing chamber inside a decompressed vacuum vessel, using plasma formed in the processing chamber, and the wafer A lock chamber that is housed inside and capable of increasing or decreasing the pressure between the pressure reduced by the supply of exhaust and gas inside and the atmospheric pressure,
After the gas in the lock chamber is sucked into a storage section disposed on the exhaust path of the lock chamber to reduce the pressure in the lock chamber to a predetermined vacuum level, the gas in the lock chamber is passed through the storage section. The vacuum processing apparatus is characterized in that the lock chamber is decompressed by exhausting the outside.

In addition, the atmosphere side block including the atmosphere transfer chamber,
A lock chamber connected to the atmospheric transfer chamber via a first gate valve; a vacuum pump for exhausting the lock chamber; a vacuum transfer chamber connected to the lock chamber via a second gate valve; and the vacuum transfer In a vacuum processing apparatus comprising a vacuum side block including a processing unit connected to the chamber via a third gate valve,
A storage section disposed on an exhaust path between the lock chamber and the vacuum pump, connected to the lock chamber via a first exhaust valve, and connected to the vacuum pump via a second exhaust valve; Have
The storage unit is configured such that after the first exhaust valve is closed and the second exhaust valve is open, the interior of the storage unit is exhausted and depressurized to a predetermined pressure, and then the second exhaust valve is closed. A vacuum processing apparatus characterized in that the lock chamber is decompressed by opening the first exhaust valve while the second exhaust valve, the first gate valve, and the second gate valve are closed. .

  According to the present invention, it is possible to reduce the influence of dew condensation and fine particles generated by rapid pressure reduction in a load lock that adjusts the pressure between the atmosphere and vacuum, and achieve both improvement in yield of semiconductor devices and improvement in throughput.

1 is a schematic overall top view (partially perspective view) of a vacuum processing apparatus (plasma etching processing apparatus) according to an embodiment of the present invention. It is sectional drawing which shows the detailed structure of the load lock provided in the plasma etching processing apparatus shown in FIG. It is a perspective view (partly permeation | transmission figure) which shows the detailed structure of the deposition trap tank provided in the exhaust line of the load lock. It is sectional drawing which shows the detailed structure of the deposition trap tank shown to FIG. 3A. It is a flowchart which shows an example of the pressure control at the time of pressure reduction exhaust_gas | exhaustion in the load lock shown in FIG. It is a graph which shows the pressure transition at the time of pressure reduction exhaust_gas | exhaustion in the load lock shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol shows the same component.

  A vacuum processing apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic overall top view (partially perspective view) of a plasma etching processing apparatus 100 which is one of vacuum processing apparatuses. The plasma etching processing apparatus 100 is roughly divided into an atmosphere side block 101 and a vacuum side block 102.

  The atmosphere side block 101 includes a hoop 107, an alignment 108, and an atmosphere transfer chamber 109. The hoop 107 is a part for storing wafers before and after the plasma processing. The alignment 108 is a part for positioning the wafer before the plasma processing. An atmospheric transfer unit 119 is provided in the atmospheric transfer chamber 109, and is a part that moves the wafers before and after the plasma processing one by one.

  The vacuum block 102 includes a load lock (lock chamber) 105, a vacuum transfer chamber 104, an intermediate chamber 111, and a plasma processing unit 103. The load lock 105 is a part that switches between atmospheric and vacuum conditions. The vacuum transfer chamber 104 has a vacuum transfer unit, and the vacuum side block 102 moves the wafer. The plasma processing unit 103 is a part that supplies a gas into the room, generates a magnetic field, and performs plasma processing on the wafer. A gate valve 120 is installed at each part of the vacuum side block 102, and each part can be completely isolated.

  In the atmosphere-side block 101, the atmosphere transfer unit 119 takes out the unprocessed wafer from the FOUP 107, and then moves the wafer to the alignment 108 to position the wafer. After the positioning is completed, the wafer is moved to the load lock 105 that is in the atmospheric pressure state. When the unprocessed wafer is moved to the load lock 105, the load lock 105 is depressurized to be in a vacuum state. After the pressure reduction of the load lock 105 is completed, the wafer is moved to the plasma processing unit 103 by the vacuum transfer unit, and plasma processing is performed in the plasma processing unit 103. After the processing is completed, the wafer is moved again to the load lock 105, and the load lock 105 is returned from the vacuum state to the atmospheric pressure state. After completion of the pressure increase of the load lock 105, the processed wafer is moved to a predetermined FOUP 107 by the atmospheric transfer unit 119.

  FIG. 2 is a sectional view showing a detailed configuration of the load lock 105 provided in the plasma etching apparatus 100 shown in FIG. The load lock 105 includes a load lock 105-1 (or 105-2), a purge line 203, and an exhaust line 204. The load lock 105-1 (or 105-2) has a gate valve 120 at the connection between the atmosphere side block 101 and the vacuum side block 102. A stage 201 for temporarily placing a wafer is installed in the load lock 105-1 (or 105-2), and is configured to hold a plurality of wafers regardless of the presence or absence of plasma processing. The exhaust line 204 includes an exhaust valve 202 and a vacuum pump 209. The exhaust valve 202 is disposed in the load lock 105-1 (or 105-2), and the vacuum pump 209 is installed under the floor.

  The unprocessed wafer transferred from the atmospheric transfer chamber 109 is placed on the stage 201 of the load lock 105-1 (or 105-2). Dry gas is supplied from the purge line 203 to the load lock 105-1 (or 105-2) to prevent foreign matter and moisture from entering the load lock 105-1 (or 105-2) from the atmospheric transfer chamber 109. ing.

  When switching to the vacuum state, first, the gate valve 120 between the atmospheric transfer chamber 109 and the gate lock 105-1 (or 105-2) is closed to make the load lock 105-1 (or 105-2) a sealed space. Subsequently, the exhaust valve 202 is opened, and the load lock 105-1 (or 105-2) is decompressed by the vacuum pump 209. After completion of the pressure reduction, the gate valve 120 between the gate lock 105-1 (or 105-2) and the vacuum transfer chamber 104 is opened, and the wafer is moved to the plasma processing unit 103 by the vacuum transfer unit 114. The wafer after the plasma processing is transferred again to the stage 201 of the load lock 105-1 (or 105-2).

  When returning to the atmospheric pressure state, dry gas is supplied from the purge line 203 to return the load lock 105-1 (or 105-2) to atmospheric pressure. After completion of the pressure increase, the gate valve 120 on the atmospheric transfer chamber side is opened, and the wafer is transferred from the load lock 105-1 (or 105-2) (hereinafter simply referred to as 105) to a predetermined position of the FOUP 107 using the atmospheric transfer unit 119. Moving.

  Thus, since the wafer always passes through the load lock 105, the throughput decreases when the exhaust time of the load lock 105 becomes longer. However, if the evacuation time is shortened, the gas temperature rapidly decreases and condensation and liquid fine particles are generated. Therefore, the yield of semiconductor devices decreases due to the condensation and fine particles generated by rapid decompression. For this reason, it is difficult to improve both yield and throughput.

  In this embodiment, in order to solve the above problems, a backflow prevention valve 213, a depot trap tank (reservoir) 211 and an exhaust valve 212 are added between the load lock 105 and the vacuum pump 209.

  3A is a perspective view of a deposition trap tank 211 provided in the exhaust line 204, and FIG. 3B is a cross-sectional view. The depot trap tank 211 includes partition plates 301-1 and 301-2, a pressure gauge 302, and a purge line 303. The partition plates 301-1 and 301-2 have a plurality of holes at different positions. The partition plates 301-1 and 301-2 are alternately arranged in the depot trap tank 211 so that the surface area is increased and the foreign matter can be effectively removed by meandering the flow in the tank. Further, by using the pressure gauge 302 and the purge line 303, the inside of the depot trap tank 211 can be set to a predetermined pressure. In order to effectively remove the reaction product after the plasma treatment and the foreign matter entering from the atmospheric transfer chamber 109, the depot trap tank 211 is a load installed between the vacuum transfer chamber 104 and the atmospheric transfer chamber 109. It is desirable to arrange in the vicinity of the lock 105.

  In this embodiment, the tank capacity is about 10 times the exhaust line capacity between the load lock 105 and the depot trap tank 211. In addition, when the load lock 105 is in an atmospheric pressure state (101.3 kPa), the pressure in the tank is set to 100 Pa so that condensation and fine particles are not generated due to sudden pressure reduction when changing from atmospheric pressure to a vacuum state. The pressure change rate was improved to improve the yield and throughput of semiconductor devices.

  Next, an explanation will be given of the operation when evacuating at a high speed to such an extent that condensation and fine particles are not generated at the time of decompression according to the present embodiment. FIG. 4 is a flowchart showing an example of pressure control during decompression exhaust in the load lock 105. First, the pressure in the deposition trap tank 211 is adjusted to 100 Pa (step S401). Specifically, the exhaust valve 202 on the load lock 105 side is closed, the exhaust valve 212 on the downstream side of the deposition trap tank 211 is opened, and the pressure in the deposition trap tank 211 is once reduced to 100 Pa or less by the vacuum pump 209. Next, the exhaust valve 212 is closed, and a dry gas is supplied from the purge line 303 to bring the pressure in the deposition trap tank 211 to 100 Pa.

  When the unprocessed wafer is transferred from the atmosphere side block 101 to the vacuum side block 102, the purge line 203 is opened for a predetermined time, and the load lock 105 is filled with dry gas in advance (step S402). Next, the purge line 203 is closed, the gate valve 120 of the atmosphere side block 101 is opened (step S403), and an unprocessed wafer is moved from the atmosphere side block 101 onto the stage 201 of the load lock 105 (step S404). Thereafter, the gate valve 120 of the atmosphere side block 101 is closed (step S405), and the load lock 105 is sealed. When the exhaust valve 202 in the load lock 105 is opened in this state (step S406), the pressure of the load lock 105 decreases until the pressure in the load lock 105 and the deposit trap tank 211 becomes the same pressure (step S407). Finally, the exhaust valve 212 is opened (step S408), and the load lock 105 is reduced to a predetermined vacuum pressure by the vacuum pump 209 (step S409). Thereafter, the exhaust valve 202 on the load lock 105 side is closed (step S410). The above steps can be executed by a control device that controls each component (exhaust valves 202 and 212, gate valve 120, purge line valve, etc.) of the vacuum processing apparatus.

  FIG. 5 is a diagram showing the pressure transition during decompression exhaust in the load lock 105, FIG. 5 (a) is a conventional method without sudden decompression, and FIG. 5 (b) is a depot trap tank according to this embodiment. FIG. 5C shows the pressure transition when using 211, and FIG. 5B shows the pressure transition when exhausted by the vacuum pump after FIG. 5B.

  In FIG. 5A, the load lock 105 is gradually exhausted so as not to generate dew condensation or fine particles due to rapid decompression, so that the exhaust time until reaching a predetermined vacuum pressure becomes longer, and the throughput decreases.

  In (b) of FIG. 5, first, the depot trap tank 211 is opened and suddenly depressurized to such an extent that no dew condensation or fine particles are generated. Finally, in FIG. 5 (c), the vacuum pump 209 is depressurized to a predetermined vacuum pressure. Therefore, the exhaust can be completed in a shorter time than the conventional exhaust time in FIG.

  By disposing the depot trap tank 211 having a constant capacity and pressure between the load lock 105 and the vacuum pump 209 in this way, the pressure change speed at which condensation and particulates due to rapid decompression do not occur without complicated valve control. In this way, vacuum exhaust can be performed in a short time. In addition, by providing the partition plate 301 in the depot trap tank 211, it is possible to effectively remove the initial reaction product after the plasma treatment that can be a nucleus of condensation and foreign matter that has entered from the atmosphere side block. Generation can be suppressed. Further, since the exhaust line 204 is structurally formed in this method, the pressure change speed is always stable regardless of the exhaust performance of the vacuum pump 209 and the distance (exhaust capacity) from the load lock 105 to the vacuum pump 209. There is also an effect that can be obtained.

  As a result of performing the plasma etching process by carrying the sample according to the procedure shown in FIG. 4 using the vacuum processing apparatus shown in FIG. 1, it became possible to improve the yield and throughput of the plasma process over a long period of time.

  As described above, according to this embodiment, there is provided a vacuum processing apparatus capable of reducing the influence of dew condensation and fine particles generated by sudden decompression in a load lock for switching between a vacuum atmosphere and an air atmosphere, and at the same time improving the yield of semiconductor devices and improving the throughput. can do.

  In addition, this invention is not limited to an above-described 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. Moreover, it is possible to add / delete / replace other configurations for a part of each configuration.

DESCRIPTION OF SYMBOLS 100 ... Plasma etching processing apparatus (vacuum processing apparatus), 101 ... Air | atmosphere side block, 102 ... Vacuum side block, 103 ... Plasma processing unit, 104 ... Vacuum transfer chamber, 105, 105-1, 105-2 ... Load lock (lock) Chamber), 107 ... hoop, 108 ... alignment, 109 ... atmospheric transfer chamber, 111 ... intermediate chamber, 114 ... vacuum transfer unit, 119 ... atmospheric transfer unit, 120 ... gate valve, 201 ... stage, 202 ... exhaust valve, 203 ... Purge line, 204 ... exhaust line, 209 ... vacuum pump, 211 ... depot trap tank (reservoir), 212 ... exhaust valve, 213 ... backflow prevention valve, 301, 301-1, 301-2 ... partition plate, 302 ... pressure Total 303 ... Purge line.

Claims (7)

A processing unit for processing a wafer to be processed disposed in a processing chamber inside the vacuum chamber having a reduced pressure by using plasma formed in the processing chamber, and storing the wafer in the interior to store exhaust and gas inside the processing chamber. A lock chamber capable of increasing or decreasing the pressure between the pressure reduced by the supply and the atmospheric pressure,
After the gas in the lock chamber is sucked into a storage section disposed on the exhaust path of the lock chamber to reduce the pressure in the lock chamber to a predetermined vacuum level, the gas in the lock chamber is passed through the storage section. A vacuum processing apparatus characterized in that the lock chamber is decompressed by exhausting to the outside.   2. The vacuum processing apparatus according to claim 1, further comprising a member that is disposed in the storage unit and attaches and captures particles contained in a gas sucked from the lock chamber.   3. The vacuum processing apparatus according to claim 1, wherein the storage unit sucks the gas in the lock chamber into the storage unit that has been decompressed in a state in which a path for exhausting the inside thereof is closed. .   The storage section opens the exhaust path after the pressure inside the storage section is reduced to a predetermined value with the exhaust path communicating with the storage section and the lock chamber closed. The vacuum processing apparatus according to claim 3, wherein the vacuum chamber is connected to the lock chamber and sucks the gas in the lock chamber. An atmospheric block including an atmospheric transfer chamber;
A lock chamber connected to the atmospheric transfer chamber via a first gate valve; a vacuum pump for exhausting the lock chamber; a vacuum transfer chamber connected to the lock chamber via a second gate valve; and the vacuum transfer In a vacuum processing apparatus comprising a vacuum side block including a processing unit connected to the chamber via a third gate valve,
A storage section disposed on an exhaust path between the lock chamber and the vacuum pump, connected to the lock chamber via a first exhaust valve, and connected to the vacuum pump via a second exhaust valve; Have
The storage unit is configured such that after the first exhaust valve is closed and the second exhaust valve is open, the interior of the storage unit is exhausted and depressurized to a predetermined pressure, and then the second exhaust valve is closed. A vacuum processing apparatus, wherein the lock chamber is decompressed by opening the first exhaust valve while the second exhaust valve, the first gate valve, and the second gate valve are closed.   The storage unit includes a first partition plate having a plurality of openings including a first opening, and a second partition plate having a plurality of openings including a second opening disposed at a position different from the first opening. 6. The vacuum processing apparatus according to claim 5, wherein the flow of exhaust gas is meandering.   The vacuum processing apparatus according to claim 5 or 6, wherein the predetermined pressure is a pressure that provides a pressure change rate at which dew condensation and generation of fine particles in the lock chamber are suppressed.

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