PLASMA PROCESSING APPARATUS AND CLEANING METHOD

The chamber is internally provided with a stage on which a substrate is disposed, and an exhaust port connected to an exhaust system around the stage. The baffle is provided around the stage, and divides a space in the chamber into a processing space where plasma processing is performed on the substrate, and an exhaust space connected to the exhaust port. The switching mechanism switches the baffle between a shield state in which the baffle shields a plasma and a transmissive state in which the baffle allows a plasma to pass therethrough. The controller controls the switching mechanism to switch the baffle from the shield state to the transmissive state or from the transmissive state to the shield state.

TECHNICAL FIELD

The present disclosure relates to a plasma processing apparatus and a cleaning method.

BACKGROUND

Patent Document 1 discloses a plasma processing chamber system including a conductance control structure and an exhaust port that is provided around a stage where a substrate of a chamber is disposed and that is connected to a vacuum pump. The conductance control structure is formed with a slit-shaped opening, and exhaust control can be performed by aligning or shifting the exhaust port and the opening.

CITATION LIST

Patent Documents

SUMMARY

The present disclosure provides a technique for efficiently removing deposits in an exhaust space.

A plasma processing apparatus according to an aspect of the present disclosure includes a chamber, a baffle, a switching mechanism, and a controller. The chamber is internally provided with a stage on which a substrate is disposed, and an exhaust port connected to an exhaust system around the stage. The baffle is provided around the stage, and divides a space in the chamber into a processing space where plasma processing is performed on the substrate, and an exhaust space connected to the exhaust port. The switching mechanism switches the baffle between a shield state in which the baffle shields a plasma and a transmissive state in which the baffle allows a plasma to pass therethrough. The controller controls the switching mechanism to switch the baffle from the shield state to the transmissive state or from the transmissive state to the shield state.

According to the present disclosure, deposits in the exhaust space can be efficiently removed.

DETAILED DESCRIPTION

Hereinafter, embodiments of a plasma processing apparatus and a cleaning method disclosed in the present application will be described in detail with reference to the drawings. The present disclosure is not limited to the plasma processing apparatus and the cleaning method.

A plasma processing apparatus for performing plasma processing such as plasma etching on a substrate while reducing a pressure in a chamber is known. In the plasma processing apparatus, a stage on which a substrate is placed is often provided at a center in a chamber, and an exhaust port is often formed near an end of a bottom surface of the chamber in consideration of space limitation and maintainability. In such a plasma processing apparatus, when a pressure in the chamber is reduced by performing exhaust from the exhaust port, a bias of an exhaust property occurs. Therefore, a baffle plate is provided around the stage to make the exhaust property uniform in the plasma processing apparatus.

In the plasma processing apparatus, deposits are deposited in the chamber. For example, in the plasma processing apparatus, deposits are deposited in a processing space where plasma processing is performed in the chamber, and deposits are also deposited in an exhaust space at a side closer to the exhaust port than the baffle plate in the chamber.

Therefore, a technique for efficiently removing deposits in the exhaust space is expected.

First Embodiment

An example of a plasma processing apparatus according to the present disclosure will be described. In the following embodiments, an example will be described in which the plasma processing apparatus according to the present disclosure is a plasma processing system having a system configuration.FIG.1is a view illustrating an example of a schematic configuration of a plasma processing system according to a first embodiment.

Hereinafter, a configuration example of a plasma processing system will be described. The plasma processing system includes a capacitively coupled plasma processing apparatus1and a controller2. The capacitively coupled plasma processing apparatus1includes a plasma processing chamber10, a gas supply20, a power source30, and an exhaust system40. Further, the plasma processing apparatus1includes a substrate support11and a gas introduction unit. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber10. The gas introduction unit includes a shower head13. The substrate support11is disposed in the plasma processing chamber10. The shower head13is disposed above the substrate support11. In one embodiment, the shower head13constitutes at least a part of a ceiling of the plasma processing chamber10. The plasma processing chamber10has a plasma processing space10sdefined by the shower head13, a sidewall10aof the plasma processing chamber10, and the substrate support11. The plasma processing chamber10has at least one gas supply port for supplying at least one processing gas into the plasma processing space10s, and at least one gas exhaust port for exhausting the gas from the plasma processing space. The sidewall10ais grounded. The shower head13and the substrate support11are electrically insulated from a housing of the plasma processing chamber10.

The substrate support11includes a main body111and a ring assembly112. The main body111has a central region (substrate support surface)111afor supporting a substrate (wafer) W, and an annular region (ring support surface)111bfor supporting the ring assembly112. The annular region111bof the main body111surrounds the central region111aof the main body111in a plan view. The substrate W is disposed on the central region111aof the main body111and the ring assembly112is disposed on the annular region111bof the main body111to surround the substrate W on the central region111aof the main body111. In one embodiment, the main body111includes a base and an electrostatic chuck. The base includes a conductive member. The conductive member of the base functions as a lower electrode. The electrostatic chuck is disposed on the base. The upper surface of the electrostatic chuck has the substrate support surface111a. The ring assembly112includes one or more annular members. At least one of the one or more annular members is an edge ring. Although not illustrated, the substrate support11may include a temperature control module configured to adjust at least one of the electrostatic chuck, the ring assembly112, and the substrate to a target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path, or a combination thereof. A heat transfer fluid, such as brine or gas, flows through the flow path. Further, the substrate support11may include a heat transfer gas supply configured to supply a heat transfer gas between the rear surface of the substrate W and the substrate support surface111a.

The shower head13is configured to introduce at least one processing gas from the gas supply20into the plasma processing space10s. The shower head13has at least one gas supply port13a, at least one gas diffusion chamber13b, and a plurality of gas introduction ports13c. The processing gas supplied to the gas supply port13apasses through the gas diffusion chamber13band is introduced into the plasma processing space10sfrom the plurality of gas introduction ports13c. Further, the shower head13includes a conductive member. The conductive member of the shower head13functions as an upper electrode. The gas introduction unit may include, in addition to the shower head13, one or a plurality of side gas injectors (SGI) that are attached to one or a plurality of openings formed in the sidewall10a.

The gas supply20may include at least one gas source21and at least one flow rate controller22. In one embodiment, the gas supply20is configured to supply at least one processing gas from the respective corresponding gas sources21to the shower head13via the respective corresponding flow rate controllers22. Each flow rate controller22may include, for example, a mass flow controller or a pressure-controlled flow rate controller. Further, the gas supply20may include one or more flow rate modulation devices that modulate or pulse flow rates of at least one processing gas.

The power source30includes an RF power source31coupled to the plasma processing chamber10via at least one impedance matching circuit. The RF power source31is configured to supply at least one RF signal (RF power), such as a source RF signal and a bias RF signal, to the conductive member of the substrate support11and/or the conductive member of the shower head13. As a result, plasma is formed from at least one processing gas supplied into the plasma processing space10s. Accordingly, the RF power source31may function as at least a portion of a plasma generator configured to generate plasma from one or more processing gases in the plasma processing chamber10. Further, supplying of the bias RF signal to the conductive member of the substrate support11can generate a bias potential in the substrate W to draw an ion component in the formed plasma to the substrate W.

In one embodiment, the RF power source31includes a first RF generator31aand a second RF generator31b. The first RF generator31ais coupled to the conductive member of the substrate support11and/or the conductive member of the shower head13via at least one impedance matching circuit, and configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 13 MHz to 150 MHz. In one embodiment, the first RF generator31amay be configured to generate a plurality of source RF signals having different frequencies. The generated one or a plurality of source RF signals are supplied to the conductive member of the substrate support11and/or the conductive member of the shower head13. The second RF generator31bis coupled to the conductive member of the substrate support11via at least one impedance matching circuit, and configured to generate a bias RF signal (bias RF power). In one embodiment, the bias RF signal has a lower frequency than the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 400 kHz to 13.56 MHz. In one embodiment, the second RF generator31bmay be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to the conductive member of the substrate support11. Further, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

Further, the power source30may include a DC power source32coupled to the plasma processing chamber10. The DC power source32includes a first DC generator32aand a second DC generator32b. In one embodiment, the first DC generator32ais connected to the conductive member of the substrate support11and configured to generate a first DC signal. The generated first bias DC signal is applied to the conductive member of the substrate support11. In one embodiment, the first DC signal may be applied to another electrode, such as an electrode in an electrostatic chuck. In one embodiment, the second DC generator32bis configured to be connected to the conductive member of the shower head13and to generate a second DC signal. The generated second DC signal is applied to the conductive member of the shower head13. In various embodiments, at least one of the first and second DC signals may be pulsed. The first and second DC generators32aand32bmay be provided in addition to the RF power source31, and the first DC generator32amay be provided instead of the second RF generator31b.

The plasma processing chamber10is formed in a cylindrical shape in which a space is formed, and the substrate support11described above is disposed at the center in the plasma processing chamber10. The substrate W having a columnar shape and subjected to plasma processing is placed on the substrate support11. A gas exhaust port10efor exhausting the inside of the plasma processing chamber10is formed at a position lower than the substrate support11around the substrate support11. In the plasma processing apparatus1according to the first embodiment, the gas exhaust port10eis formed at a bottom portion of the plasma processing chamber10.

The exhaust system40may be connected to, for example, the gas exhaust port10edisposed at a bottom portion of the plasma processing chamber10. The exhaust system40may include a pressure adjusting valve and a vacuum pump. The pressure in the plasma processing space10sis adjusted by the pressure adjusting valve. The vacuum pump may include a turbo molecular pump, a dry pump, or a combination thereof.

The plasma processing chamber10includes a baffle plate14around the substrate support11. The baffle plate14has a flat annular shape. Flat planes are formed on an inner peripheral side and an outer peripheral side of the baffle plate14according to the first embodiment, and a stepped portion is formed such that the outer peripheral side is higher than the inner peripheral side. The baffle plate14may be formed of a plane having no stepped portion. The baffle plate14is disposed in a manner of surrounding a periphery of the substrate support11. The inner peripheral side of the baffle plate14is fixed to the substrate support11, and the outer peripheral side of the baffle plate14is fixed to an inner sidewall of the plasma processing chamber10. The baffle plate14is formed to be conductive. For example, the baffle plate14is made of a conductive material such as a conductive metal. The baffle plate14is electrically connected to the sidewall10aof the plasma processing chamber10and is grounded through the sidewall10a. A large number of slits are formed in the baffle plate14, and a gas can pass through the baffle plate14. The inside of the plasma processing chamber10is divided by the baffle plate14into the plasma processing space10sthat is a processing space where plasma processing is performed on the substrate W and an exhaust space10tthat includes the gas exhaust port10e. The plasma processing space10sis a space upstream of the baffle plate14relative to a flow of an exhaust gas toward the gas exhaust port10e. The exhaust space10tis a space downstream of the baffle plate14relative to a flow of the exhaust gas toward the gas exhaust port10e.

The controller2processes computer-executable instructions for instructing the plasma processing apparatus1to execute various steps described herein below. The controller2may be configured to control the respective components of the plasma processing apparatus1to execute the various steps described herein below. In an embodiment, part or all of the controller2may be included in the plasma processing apparatus1. The controller2may include, for example, a computer2a. For example, the computer2amay include a processor (central processing unit (CPU))2a1, a storage unit2a2, and a communication interface2a3. The processor2a1may be configured to perform various control operations based on a program stored in the storage unit2a2. The storage unit2a2may include a random access memory (RAM), a read only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface2a3may communicate with the plasma processing apparatus1via a communication line such as a local area network (LAN).

Next, a flow of performing plasma processing such as plasma etching on the substrate W by the plasma processing system according to the embodiment will be described briefly. The substrate W is placed on the substrate support11by a conveyance device such as a conveyance arm (not illustrated). When the plasma processing is performed, the plasma processing apparatus1reduces a pressure in the plasma processing chamber10using the exhaust system40. The plasma processing apparatus1supplies a processing gas from the gas supply20and introduces the processing gas through the shower head13into the plasma processing chamber10. Then, the plasma processing apparatus1supplies at least one RF signal from the RF power source31to generate a plasma in the plasma processing space10s, and performs the plasma processing on the substrate W.

When the plasma processing is performed, deposits are deposited in the plasma processing chamber10. The deposits are deposited in the plasma processing space10s, and the deposits are likely to be deposited in the exhaust space10tat a side close to the gas exhaust port10eof the baffle plate14in the plasma processing chamber10. The deposits include products generated by the plasma processing, ash generated by heat, and the like.

When the plasma processing is performed, deposits are deposited in the plasma processing space10sand the exhaust space10tin the plasma processing apparatus1. Therefore, the plasma processing apparatus1performs cleaning processing for removing the deposits. When the cleaning processing is performed, the plasma processing apparatus1reduces a pressure in the plasma processing chamber10using the exhaust system40. The plasma processing apparatus1supplies a cleaning gas from the gas supply20, and introduces the cleaning gas through the shower head13into the plasma processing chamber10. Then, the plasma processing apparatus1supplies at least one RF signal from the RF power source31to generate a plasma in the plasma processing space10s, and performs plasma cleaning. Dry cleaning may be performed after placing a dummy substrate on the substrate support11in order to protect a surface of the substrate support11.

The cleaning gas may be any type of gas as long as deposits can be removed. For example, when the deposits are organic products generated from an etching gas during an etching process on the substrate W, examples of the cleaning gas include an oxygen-containing gas such as O2, O3, CO, and CO2. In addition, when the deposits are organic films containing a metal such as tungsten (W) and titanium (Ti), examples of the cleaning gas include an oxygen-containing gas such as O2, CO, O3, and CO2, a gas obtained by adding a halogen-containing gas such as CF4, Cl2to the oxygen-containing gas, a F2gas, and a ClF3gas. Further, when the deposits are deposits obtained by metal etching such as ruthenium (Ru), cobalt (Co), and iron (Fe), examples of the cleaning gas include a methanol (CH3OH) gas. Further, a plurality of types of gases may be switched and supplied as the cleaning gas. When the deposits are stacked films of a plurality of products or organic films, a gas type may be selected and supplied as the cleaning gas according to a type of a film exposed on an outermost surface of the stacked films. When the cleaning processing is performed at the same time with the plasma processing including a plurality of pieces of step processing in which reaction products serving as deposits are different, the cleaning gas may be switched for each step processing.

Here, in order to improve processing efficiency of the plasma processing and improve uniformity on the substrate W, the baffle plate14shields a plasma such that a plasma generated in the plasma processing space10sdoes not flow into the exhaust space10tin the plasma processing apparatus1in the related art.

However, since a plasma of the cleaning gas during plasma cleaning is also shielded by the baffle plate14, a cleaning rate of deposits in the exhaust space10tis low and the deposits cannot be completely separated in the plasma processing apparatus1in the related art.

FIG.2is a view illustrating deposition of deposits in the exhaust space10taccording to the first embodiment.FIG.2is an enlarged view illustrating the vicinity of a side surface of the substrate support11of the plasma processing chamber10. InFIG.2, a plasma is shielded by the baffle plate14. Therefore, when a cumulative time in the plasma processing is long, for example, deposits50are deposited on wall surfaces of the substrate support11and the sidewall10abelow the baffle plate14in the plasma processing apparatus1in the related art. When the deposits50are deposited in the exhaust space10t, for example, the following problems occur. The deposits50in the exhaust space10tbecome a dust source of particles. Further, the deposits50in the exhaust space10tmay fall to a pressure adjusting valve of the exhaust system40to change an opening degree of the pressure adjusting valve, and a pressure in the plasma processing chamber10may be changed. In the plasma processing apparatus1in the related art, it is necessary to manually remove the deposits50every maintenance cycle, which takes time for the maintenance.

Therefore, in the plasma processing apparatus1according to the embodiment, the baffle plate14can be switched between a shield state in which the baffle plate14shields a plasma and a transmissive state in which the baffle plate14allows a plasma to pass therethrough. For example, a plurality of slits are formed in the baffle plate14according to the first embodiment, and the baffle plate14can be switched between the shield state and the transmissive state by changing widths of the slits. The baffle plate14has an opening formed along a circumferential direction of the substrate support11. The baffle plate14according to the first embodiment has an opening formed in a flat plane on an inner peripheral side. The baffle plate14may have an opening14bor blades15to be described later on a flat plane or a stepped surface on an outer peripheral side.

FIG.3is a view illustrating an example of a configuration of the baffle plate14according to the first embodiment.FIG.3shows a flat plane14aon the inner peripheral side of the baffle plate14. The opening14bis formed in the plane14aalong a circumferential direction of the baffle plate14. A plurality of blades15are disposed side by side in the opening14b. Each blade15is fixed to a rod-shaped shaft15a, and is rotatable around the shaft15aserving as a rotation axis. Gaps that function as slits16are formed between the blades15. The shaft15aof each blade15is supported in a rotatable manner by the plane14asandwiching the opening14bof the baffle plate14. The shaft15aof each blade15is rotated by a switching mechanism. The plane14aof the baffle plate14is provided with a shaft17serving as the switching mechanism. The shaft15aof each blade15is provided with a worm gear, and rotation of the shaft17is transmitted to the shaft15athrough the worm gear to rotate the shaft15a. The shaft17is rotated by a drive force of a power source such as a servo motor (not illustrated). The controller2can control the power source to control the rotation of the shaft17, thereby controlling a rotation angle of each blade15. The switching mechanism according to the first embodiment may have any configuration as long as each blade15can be rotated around the shaft15aserving as a rotation axis.

FIG.4is a view illustrating an example of the blades15according to the first embodiment. As described above, each blade15is rotatable around the shaft15aserving as a rotation axis. The baffle plate14changes a width of the slit16(the gap) between the blades15by changing a rotation angle of each blade15.FIG.5is a view illustrating an example of a change of the slit16according to the first embodiment. For example, the width of the slit16is narrowed by placing a plane of each blade15in a horizontal state, and the width of the slit16is widened by placing a plane of each blade15in a vertical state in the baffle plate14.

The baffle plate14according to the first embodiment can be switched between the shield state in which the baffle plate14shields a plasma and the transmissive state in which the baffle plate14allows a plasma to pass therethrough by controlling a rotation angle of each blade15to change the width of the slit16.FIG.6is a view illustrating the shield state and the transmissive state of the baffle plate14according to the first embodiment. When the width of the slit16is smaller than twice a sheath width of the plasma, the baffle plate14does not allow the plasma to pass through the slit16and shields the plasma. When the width of the slit16is twice or more the sheath width of the plasma, the baffle plate14allows the plasma to pass through the slit16, and transmits the plasma. The baffle plate14is configured such that when the plane of each blade15is horizontal, a width d1of the slit16is smaller than twice a sheath width dshof the plasma, and when the plane of each blade15is vertical, a width d2of the slit16is twice or more the sheath width dsh.

The controller2controls the baffle plate14to be in the shield state when the plasma processing is performed on the substrate W, and controls the baffle plate14to be in the transmissive state when the plasma cleaning is performed in the plasma processing chamber10.

For example, the controller2controls the rotation angle of each blade15by controlling the power source to control the width of the slit16of the baffle plate14. When the plasma processing is performed, the controller2controls the baffle plate14to be in the shield state by setting the width of the slit16of the baffle plate14to be smaller than twice the sheath width of the plasma. For example, when the plasma processing is performed, the controller2controls the rotation angle such that the plane of each blade15is horizontal to set the baffle plate14to the shield state. Accordingly, since the plasma generated in the plasma processing space10sduring the plasma processing performed on the substrate W is shielded by the baffle plate14and remains in the plasma processing space10s, processing efficiency of the plasma processing is improved in the plasma processing apparatus1. The plasma processing apparatus1can perform the plasma processing with high uniformity on the substrate W.

When the plasma cleaning is performed, the controller2controls the baffle plate14to be in the transmissive state by setting the width of the slit16of the baffle plate14to be twice or more the sheath width of the plasma. For example, when the plasma processing is performed, the controller2controls the rotation angle such that the plane of each blade15is vertical to set the baffle plate14to the transmissive state. Accordingly, the plasma generated in the plasma processing space10sduring the plasma cleaning is transmitted through the baffle plate14and flows into the exhaust space10t, and thus the plasma processing apparatus1can efficiently remove deposits in the exhaust space10t.

Next, a flow of processing of a cleaning method performed by the plasma processing apparatus1according to the embodiment will be described.FIG.7is a view illustrating an example of a processing sequence of a cleaning method according to the embodiment. The processing of the cleaning method shown inFIG.7is performed when the plasma processing is performed on the substrate W or the plasma cleaning is performed.

The controller2determines whether processing to be performed is the plasma processing (S10). When the processing to be performed is the plasma processing (S10: Yes), the controller2controls the baffle plate14to the shield state (S11), and ends the processing. For example, the controller2controls the rotation angle of each blade15by controlling the power source, and sets the width of the slit16of the baffle plate14to be smaller than twice the sheath width of the plasma to set the baffle plate14to the shield state.

On the other hand, when the processing to be performed is the plasma cleaning and is not the plasma processing (S10: No), the controller2controls the baffle plate14to be in the transmissive state (S12), and ends the processing. For example, the controller2controls the rotation angle of each blade15by controlling the power source, and sets the width of the slit16of the baffle plate14to be twice or more the sheath width of the plasma to set the baffle plate14to be in the transmissive state.

Although an example is described in the first embodiment in which the entire periphery of the baffle plate14can be uniformly switched between the shield state and the transmissive state, the present disclosure is not limited thereto. The baffle plate14may be divided into a plurality of regions along the circumferential direction of the substrate support11, and the regions may be individually switched between the shield state and the transmissive state.FIG.8is a view illustrating another example of the configuration of the baffle plate14according to the first embodiment. The baffle plate14has a flat annular shape. The baffle plate14is divided into, for example, four regions18(18ato18d) along the circumferential direction. The four regions18each have an opening19, and a plurality of blades15are disposed side by side in the opening19. The baffle plate14is configured such that the rotation angle of the blade15of each region18can be controlled by a switching mechanism.

When the plasma processing is performed on the substrate W, the controller2controls all of the regions18of the baffle plate14to be in the shield state, and when the plasma cleaning is performed in the plasma processing chamber10, the controller2controls a part or all of the regions18of the baffle plate14to be in the transmissive state. For example, when the plasma cleaning is performed in the plasma processing chamber10, the controller2controls the four regions18of the baffle plate14to be in the transmissive state sequentially.FIG.9is a view illustrating an example of switching regions18set to the transmissive state during plasma cleaning according to the first embodiment. InFIG.9, a diagonal-line pattern is given to the region18in the shield state, and a dot pattern is given to the region18in the transmissive state. In (A) ofFIG.9, all of the regions18ato18dare in the shield state. In (B) ofFIG.9, the regions18bto18dare set to the shield state, and shielding is set to OFF in the region18aand the region8ais set to the transmissive state. In (C) ofFIG.9, the regions18are sequentially controlled to be in the transmissive state, and the region18bis switched to the transmissive state and the region18ais switched to the shield state from the states shown in (B) ofFIG.9. Accordingly, the plasma processing apparatus1can locally and intensively causes a plasma of a cleaning gas to flow into the exhaust space10tthrough the region18set to the transmissive state during the plasma cleaning. Accordingly, the plasma processing apparatus1can efficiently remove, at a high rate, deposits in the exhaust space10tthrough the region18set to the transmissive state. Further, the plasma processing apparatus1controls the regions18of the baffle plate14to be in the transmissive state sequentially, thereby sequentially switching the regions18in the transmissive state, and the entire exhaust space10tcan be cleaned.

When the baffle plate14is configured as shown inFIG.8, the plasma processing apparatus1can partially adjust a pressure in the plasma processing chamber10by adjusting an inclination of the blade15in each region18. For example, since a pressure on a surface of the substrate W can be partially adjusted in the circumferential direction during the plasma processing, the plasma processing apparatus1can also be used to eliminate a bias of an etching rate. Further, since a plasma density on the baffle plate14is reduced when a part of the baffle plate14is set to the transmissive state during the plasma processing, a plasma density on the surface of the substrate W can be partially adjusted in the circumferential direction, and the plasma processing apparatus1can also be used to eliminate a bias of an etching rate.

Although the region18is divided into four regions inFIG.8, the present disclosure is not limited thereto. For example, the region18may be divided into two or more regions. Deposits in the exhaust space10tcan be further efficiently removed through the region18set to the transmissive state at a high rate by dividing the region18into further more regions such as 8 regions and 12 regions. Further, finer partial adjustment can be performed for the pressure or the plasma density in the circumferential direction during the plasma processing, and the plasma processing apparatus1can also be used to eliminate a bias of an etching rate.

As described above, the plasma processing apparatus1according to the first embodiment includes the plasma processing chamber10(a chamber), the baffle plate14, the switching mechanism (the shaft17, a motor that rotationally drives the shaft17, and the like), and the controller2. The plasma processing chamber10is internally provided with the substrate support11(a stage) on which the substrate W is disposed, and the gas exhaust port10e(an exhaust port) connected to an exhaust system around the substrate support11. The baffle plate14is provided around the substrate support11, and divides a space in the plasma processing chamber10into the plasma processing space10swhere the plasma processing is performed on the substrate W and the exhaust space10tconnected to the gas exhaust port10e. The switching mechanism switches the baffle plate14between the shield state in which the baffle plate14shields a plasma and the transmissive state in which the baffle plate14allows a plasma to pass therethrough. When a plasma is generated in the plasma processing chamber10and the plasma processing is performed on the substrate W, the controller2controls the switching mechanism to set the baffle plate14to the shield state. Further, when the plasma cleaning is performed in the plasma processing chamber10, the controller2controls the switching mechanism to set the baffle plate14to the transmissive state. Accordingly, the plasma processing apparatus1can efficiently remove deposits in the exhaust space10t.

Further, the baffle plate14is formed with a plurality of slits16. The switching mechanism switches the baffle plate14between the shield state and the transmissive state by changing widths of the slits16. In this manner, the plasma processing apparatus1can switch the baffle plate14between the shield state and the transmissive state by changing the widths of the slits16of the baffle plate14.

The baffle plate14has the opening14bformed along a periphery of the substrate support11, a plurality of blades15fixed to the shafts15aare disposed side by side in the opening14b, and the slits16are formed between the blades15. The switching mechanism switches the baffle plate14between the shield state and the transmissive state by rotating the shafts15aof the blades15to change the widths of the slits16. Accordingly, the plasma processing apparatus1can switch the baffle plate14between the shield state and the transmissive state by rotating the blades15disposed in the opening14b.

The switching mechanism switches the baffle plate14to the shield state by setting the width of the slit16to be smaller than twice the sheath width of the plasma, and switches the baffle plate14to the transmissive state by setting the width of the slit16to be twice or more the sheath width. Accordingly, the plasma processing apparatus1can switch the baffle plate14between the shield state and the transmissive state.

Further, the baffle plate14is divided into a plurality of regions18along the circumferential direction of the substrate support11, and the regions18can be individually switched between the shield state and the transmissive state. The switching mechanism individually switches the regions18between the shield state and the transmissive state. Accordingly, the plasma processing apparatus1can locally and intensively causes a plasma of a cleaning gas to flow into the exhaust space10t, and can locally perform cleaning.

When the plasma processing is performed on the substrate W, the controller2controls the switching mechanism to set the regions18of the baffle plate14to the shield state. Further, when the plasma cleaning is performed in the plasma processing chamber10, the controller2controls the switching mechanism to set a part of or all of the regions18of the baffle plate14to the transmissive state. Accordingly, the plasma processing apparatus1can cause a plasma of a cleaning gas flow into the exhaust space10tthrough the region18set to the transmissive state, and can locally or entirely clean a part of the exhaust space10t.

When the plasma cleaning is performed in the plasma processing chamber10, the controller2controls the switching mechanism to sequentially set the regions18of the baffle plate14to the transmissive state. Accordingly, the plasma processing apparatus1can locally and intensively cause a plasma of a cleaning gas to flow into the exhaust space10tthrough the region18set to the transmissive state, and thus deposits in the exhaust space10tcan be efficiently removed through the region18set to the transmissive state at a high rate. Further, the plasma processing apparatus1controls the regions18of the baffle plate14to be in the transmissive state sequentially, thereby sequentially switching the regions18in the transmissive state, and the entire exhaust space10tcan be cleaned.

Second Embodiment

Next, a second embodiment will be described. Since the plasma processing system, the plasma processing apparatus1, and the controller2according to the second embodiment have the same configurations as those in the first embodiment, descriptions of the same portions will be omitted, and differences will be mainly described.

FIG.10is a view illustrating a configuration of a plasma processing apparatus1according to a second embodiment.FIG.10is an enlarged view illustrating the vicinity of a side surface of the substrate support11of the plasma processing chamber10.

Similar to the first embodiment, the baffle plate14is provided around the substrate support11. A large number of slits are formed in the baffle plate14, and a gas can pass through the baffle plate14. Each slit is formed to have a width smaller than twice the sheath width of the plasma.

The baffle plate14can be switched between the shield state in which the baffle plate14shields a plasma and the transmissive state in which the baffle plate14allows a plasma to pass therethrough. For example, the baffle plate14according to the second embodiment can be switched between a ground potential and a floating state. The baffle plate14is provided with an insulating member such as a dielectric at an inner peripheral portion in contact with the substrate support11and at an outer peripheral portion in contact with the sidewall10a, and is insulated from the substrate support11and the sidewall10a. Further, switches60(60a,60b) that switch the substrate support11, the sidewall10a, and the baffle plate14between a conductive state and a non-conductive state are provided at one or more locations along the circumferential direction of the baffle plate14. The controller2switches the baffle plate14between the ground potential and the floating state by controlling ON and OFF of the switches60.

When the switch60is turned on, the baffle plate14is electrically connected to the sidewall10aswitched to the ground potential and is switched to the ground potential, thereby to the shield state, and when the switch60is turned off, the baffle plate14is switched to the floating state, thereby to the transmissive state.

The controller2controls the baffle plate14to be in the shield state when the plasma processing is performed on the substrate W, and controls the baffle plate14to be in the transmissive state when the plasma cleaning is performed in the plasma processing chamber10. For example, the controller2controls the switch60to be turned on to set the baffle plate14to the shield state. Accordingly, since the plasma generated in the plasma processing space10sduring the plasma processing performed on the substrate W is shielded by the baffle plate14and remains in the plasma processing space10s, processing efficiency of the plasma processing is improved in the plasma processing apparatus1. The plasma processing apparatus1can perform the plasma processing with high uniformity on the substrate W. When the plasma cleaning is performed, the controller2controls the switch60to be turned off to set the baffle plate14to the transmissive state. Accordingly, the plasma generated in the plasma processing space10sduring the plasma cleaning is transmitted through the baffle plate14and flows into the exhaust space10t, and thus the plasma processing apparatus1can efficiently remove deposits in the exhaust space10t.

Although an example is described in the second embodiment in which the entire periphery of the baffle plate14can be uniformly switched between the shield state and the transmissive state, the present disclosure is not limited thereto. In the second embodiment, the baffle plate14may also be divided into a plurality of regions along the circumferential direction of the substrate support11, and the regions may be individually switched between the shield state and the transmissive state. The baffle plate14is divided into a plurality of regions along the circumferential direction of the substrate support11, and is configured such that the regions can be individually switched between the ground potential and the floating state, so that the regions can be individually switched between the shield state and the transmissive state.

Although the switch60includes two switches of the switch60abetween the substrate support11and the baffle plate14and the switch60bbetween the sidewall10aand the baffle plate14, the present disclosure is not limited thereto. For example, the switch60may include only one of the switch60aand the switch60b, and the other one that is not a switch may be fixed by an insulator. The substrate support11and the baffle plate14, and the sidewall10aand the baffle plate14may both be fixed by an insulator, may be connected to another ground potential location via another switch by a lead wire from the baffle plate14, and the baffle plate14may be switched between the shield state and the transmissive state by turning on and turning off the switch.

As described above, the plasma processing apparatus1according to the second embodiment includes the switching mechanism. The switching mechanism can switch the baffle plate14between the ground potential and the floating state. The switching mechanism switches the baffle plate14to the shield state by switching the baffle plate14to the ground potential and switches the baffle plate14to the transmissive state by switching the baffle plate14to the floating state. In this manner, the plasma processing apparatus1can switch the baffle plate14between the shield state and the transmissive state by switching the baffle plate14between the ground potential and the floating state.

The switching mechanism is provided at a connection location between a conductive member set to a ground potential and the baffle plate14, and is implemented as the switch60that switches the conductive member and the baffle plate14between a conductive state and a non-conductive state. Accordingly, the plasma processing apparatus1can easily switch the baffle plate14between the ground potential and the floating state by using the switch60.

Hitherto, the embodiment has been described above. The embodiment disclosed herein is illustrative and should not be construed as limiting in all aspects. The embodiment described above may be embodied in various forms. The embodiment described above may be omitted, replaced, or modified in various forms without departing from the scope and spirit of the claims.

For example, although an example is described in the above embodiments in which the plasma processing is performed on a semiconductor wafer serving as the substrate W, the present disclosure is not limited thereto. The substrate W may be any substrate.

Although an example is described in which the controller2controls the switching mechanism to switch the baffle plate14to the shield state during the plasma processing and to switch the baffle plate14to the transmissive state during the cleaning processing, the present disclosure is not limited thereto. For example, when the deposits50on the substrate W, on the substrate support11, and on a wall surface of the sidewall10aof the plasma processing space10sare mainly cleaned, the baffle plate14may also be switched to the shield state even during the same cleaning processing. That is, the controller2may control the switching mechanism to switch the baffle plate14to the shield state during the cleaning processing. For example, when ashing is performed to remove a mask on the substrate W during the plasma processing, the wall surface of the sidewall10aof the exhaust space10tcan also be cleaned at the same time by switching the baffle plate14to the transmissive state, and throughput can be improved. Further, since a plasma density on the baffle plate14is reduced when a part of the baffle plate14is set to the transmissive state during the plasma processing, a plasma density on the surface of the substrate W can be partially adjusted in the circumferential direction, and the plasma processing apparatus1can also be used to eliminate a bias of an etching rate. That is, the controller2may control the switching mechanism to switch the baffle plate14to the transmissive state during the plasma processing.

Although an example is described in the above embodiments in which the plasma processing apparatus performs plasma etching as the plasma processing, the present disclosure is not limited thereto. The plasma processing apparatus may be any apparatus as long as the apparatus performs plasma processing on the substrate W. For example, the plasma processing apparatus may be a film forming apparatus or the like that generates a plasma to form a film.

It shall be understood that the embodiments disclosed herein are illustrative and are not restrictive in all aspects. Indeed, the above-described embodiments can be implemented in various forms. The embodiments described above may be omitted, replaced, or modified in various forms without departing from the scope and spirit of the appended claims.

With respect to the above-described embodiments, the following appendixes will be further disclosed.

A plasma processing apparatus including:a chamber internally provided with a stage on which a substrate is disposed and provided with an exhaust port connected to an exhaust system around the stage;a baffle provided around the stage and configured to divide a space in the chamber into a processing space where plasma processing is performed on the substrate and an exhaust space connected to the exhaust port;a switching mechanism configured to switch the baffle between a shield state in which the baffle shields a plasma and a transmissive state in which the baffle allows a plasma to pass therethrough; anda controller configured to control the switching mechanism to switch the baffle from the shield state to the transmissive state or from the transmissive state to the shield state.

The plasma processing apparatus according to Appendix 1, in which the controller controls the switching mechanism to switch the baffle to the shield state when a plasma is generated in the chamber and the plasma processing is performed on the substrate, and to switch the baffle to the transmissive state when plasma cleaning is performed in the chamber.

The plasma processing apparatus according to Appendix 1 or 2, in which

the baffle has a plurality of slits, and

the switching mechanism switches the baffle between the shield state and the transmissive state by changing widths of the slits.

The plasma processing apparatus according to any one of Appendices 1 to 3, in which

the baffle has an opening formed along a periphery of the stage, a plurality of blades fixed to axes are disposed side by side in the opening, and slits are formed between the blades, and

the switching mechanism switches the baffle between the shield state and the transmissive state by rotating the axes of the blades to change widths of the slits.

The plasma processing apparatus according to Appendix 3 or 4, in which

the switching mechanism switches the baffle to the shield state by setting the widths of the slits to be smaller than twice a sheath width of the plasma, and switches the baffle to the transmissive state by setting the widths of the slits to twice or more the sheath width.

The plasma processing apparatus according to Appendix 1 or 2, in which

the switching mechanism is configured to switch the baffle between a ground potential and a floating state, switch the baffle to the shield state by switching the baffle to the ground potential, and switch the baffle to the transmissive state by switching the baffle to the floating state.

The plasma processing apparatus according to Appendix 6, in which the switching mechanism is provided at a connection location between a conductive member set to a ground potential and the baffle, and is implemented as a switch configured to switch the conductive member and the baffle between a conductive state and a non-conductive state.

The plasma processing apparatus according to any one of Appendices 1 to 7, in which

the baffle is divided into a plurality of regions along a circumferential direction of the stage,

the regions are individually switchable between the shield state and the transmissive state, and

the switching mechanism individually switches the regions between the shield state and the transmissive state.

The plasma processing apparatus according to Appendix 8, in which

the controller controls the switching mechanism to switch the regions of the baffle to the shield state when the plasma processing is performed on the substrate, and switch a part or all of the regions of the baffle to the transmissive state when the plasma cleaning is performed in the chamber.

The plasma processing apparatus according to Appendix 9, in which

the controller controls the switching mechanism to sequentially switch the regions of the baffle to the transmissive state when the plasma cleaning is performed in the chamber.

A cleaning method for a plasma processing apparatus includinga chamber internally provided with a stage on which a substrate is disposed and provided with an exhaust port connected to an exhaust system around the stage,a baffle provided around the stage and configured to divide a space in the chamber into a processing space where plasma processing is performed on the substrate and an exhaust space connected to the exhaust port, anda switching mechanism configured to switch the baffle between a shield state in which the baffle shields a plasma and a transmissive state in which the baffle allows a plasma to pass therethrough,the cleaning method including:controlling the switching mechanism to switch the baffle from the shield state to the transmissive state or from the transmissive state to the shield state.