A substrate processing apparatus includes a holding device that includes a conductive member and holds a substrate, a conduction path structure that includes a conductive material and positioned such that the conduction path structure is in contact with the holding device, a supply device that supplies a processing liquid to the substrate held by the holding device, and a grounding structure including a variable resistance device that changes a resistance such that the grounding structure has a first end portion connected the conduction path structure and a second end portion connected to a ground potential.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is based upon and claims the benefit of priority to Japanese Patent Application No. 2016-065660, filed Mar. 29, 2016, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

An embodiment disclosed herein relates to a substrate processing apparatus and a substrate processing method.

Description of Background Art

Japanese Patent Laid-Open Publication No. 2003-092343 describes a substrate processing apparatus that processes a substrate such as a semiconductor wafer or a glass substrate by supplying a processing liquid to the substrate. The entire contents of this publication are incorporated herein by reference.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a substrate processing apparatus includes a holding device that includes a conductive member and holds a substrate, a conduction path structure that includes a conductive material and positioned such that the conduction path structure is in contact with the holding device, a supply device that supplies a processing liquid to the substrate held by the holding device, and a grounding structure including a variable resistance device that changes a resistance such that the grounding structure has a first end portion connected the conduction path structure and a second end portion connected to a ground potential.

According to another aspect of the present invention, a substrate processing method includes holding a substrate, and supplying a processing liquid to the substrate connected to a ground potential. The supplying of the processing liquid includes changing a resistance between the substrate and the ground potential by a variable resistance device that changes the resistance.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1is a view schematically showing the structure of a substrate processing system according to an embodiment of the present invention. In the following, X, Y and Z axes intersecting each other at right angles are specified to clarify positional relationships, and a positive direction of the Z axis is set as the vertically upward direction.

As shown inFIG. 1, substrate processing system1is provided with loading station2and processing station3. Loading station2and processing station3are positioned to be adjacent to each other.

Loading station2includes carrier mounting zone11and transport zone12. Multiple carriers (C), which horizontally accommodate multiple substrates—semiconductor wafers (hereinafter wafers (W)) in the present embodiment—are mounted in carrier mounting zone11.

Transport zone12is positioned adjacent to carrier mounting zone11, and is provided with substrate transport apparatus13and delivery table14. Substrate transport apparatus13has a wafer holding mechanism for holding a wafer (W). Substrate transport apparatus13is capable of moving horizontally and vertically as well as rotating around the vertical axis, and transports a wafer (W) between a carrier (C) and delivery part14using the wafer holding mechanism.

Processing station3is positioned adjacent to transport zone12. Processing station3includes transport zone15and multiple processing units16. Multiple processing units16are aligned on each side of transport zone15.

Substrate transport device17is provided in transport zone15. Substrate transport device17includes a wafer holding mechanism for holding a wafer (W). In addition, substrate transport device17is capable of moving horizontally and vertically as well as rotating around the vertical axis, and transports a wafer (W) between delivery part14and processing unit16using the wafer holding mechanism.

Processing unit16conducts predetermined treatments on a wafer (W) transported by substrate transport device17.

Substrate processing system1includes control device4. Control device4is a computer, for example, and includes control unit18and memory unit19. Memory unit19stores a program for controlling various treatments carried out in substrate processing system1. Control unit18controls operations to be performed in substrate processing system1by reading out and executing the program stored in memory unit19.

Such a program may be stored in a computer-readable medium and installed from the memory medium onto memory unit19of control device4. Examples of a computer-readable medium are hard disks (HD), flexible disks (FD), compact discs (CD), magneto-optical discs (MO), memory cards and the like.

In substrate processing system1structured as above, first, substrate transport apparatus13of loading station2takes out a wafer (W) from carrier (C) in carrier mounting zone11, and loads the wafer (W) on delivery table14. The wafer (W) loaded on delivery part14is unloaded by substrate transport device17of processing station3to be loaded into processing unit16.

The wafer (W) loaded into processing unit16is treated in processing unit16and is unloaded from processing unit16by substrate transfer device17to be loaded onto delivery table14. Then, the treated wafer (W) loaded on delivery part14is returned by substrate transport apparatus13to carrier (C) in carrier mounting zone11.

A schematic structure of a processing unit16is described with reference toFIG. 2.FIG. 2is a schematic cross-sectional view illustrating the structure of the processing unit16.

As illustrated inFIG. 2, the processing unit16includes a collection cup50, a holding part60, a rotating ring70, a rotation mechanism80, a substrate lift mechanism90, a processing liquid supply part100, a top plate110, a lift mechanism120, and an inert gas supply part130.

The collection cup50, the holding part60and the rotating ring70are accommodated in a chamber (not illustrated in the drawings). An FFU (Fan Filter Unit) (not illustrated in the drawings) is provided in a ceiling part of the chamber. FFU forms a down flow in the chamber.

The holding part60has a base plate61and multiple support pins (61b). The base plate61is horizontally provided and has a circular recess part (61a) at a center. Here, the base plate61is integrally formed with a later-described rotation shaft81. However, it is also possible that the base plate61and the rotation shaft81are formed as separate bodies.

The multiple support pins (61b) are provided at substantially equal intervals along a circumferential direction of the holding part60on an upper surface of the holding part60. The support pins (61b) are each provided protruding from the holding part60with a front end portion facing upward, and support a wafer (W) from below in a state in which the wafer (W) floats from the holding part60.

The rotating ring70is positioned on an outer side of an outer periphery of the wafer (W) that is supported by the holding part60, and is provided so as to surround an entire circumference of a peripheral edge portion of the wafer (W). Further, the rotating ring70is coupled to the holding part60and is provided capable of integrally rotating with the holding part60.

The rotating ring70functions as a liquid receiving part and guides a processing liquid to a drain cup51for drainage, the processing liquid being supplied to a back surface side of the wafer (W) by the processing liquid supply part100(to be described later) and being used for the processing of the wafer (W). Further, the rotating ring70also plays a role of preventing a processing liquid, which is supplied to the back surface side of the wafer (W) and is scattered from the rotating wafer (W) toward an outer peripheral side, from being bounced back and returning to the wafer (W) again, or from coming around to an upper surface side of the wafer (W).

The rotation mechanism80includes the rotation shaft81and an electric motor82. The rotation shaft81rotatably supports the base plate61. Specifically, the rotation shaft81is provided so as to extend downward from the base plate61, and has a cylindrical shape in which a through hole (81a) is provided at a center.

The electric motor82causes the rotation shaft81to rotate about a vertical axis. Due to the rotation of the rotation shaft81, the holding part60and the rotating ring70integrally rotate with each other. A specific structure of the rotation mechanism80will be described later with reference toFIG. 5.

The substrate lift mechanism90has a lift plate91and a lift shaft92that are provided movable up and down in the recess part (61a) of the base plate61and the through hole (81a) of the rotation shaft81. The lift plate91has multiple, for example, five, lift pins (91a) on a peripheral edge thereof.

The lift shaft92extends downward from the lift plate91. A processing liquid supply pipe (100a) is provided at centers of the lift plate91and the lift shaft92. Further, a cylinder mechanism (92a) is connected to the lift shaft92. By raising or lowering the lift shaft92, the lift pins (91a) are raised or lowered between a position lower than a height position at which the wafer (W) is supported by the support pins (61b) and a position higher than the height position. As a result, the wafer (W) is raised or lowered, and loading or unloading of the wafer (W) to or from the holding part60is performed.

The processing liquid supply part100has the processing liquid supply pipe (100a). As described above, the processing liquid supply pipe (100a) is provided so as to extend along an inner space of the lift plate91and the lift shaft92.

The processing liquid supply pipe (100a) guides a processing liquid supplied from pipes of a processing liquid pipe group (100b) to the back surface side of the wafer (W). Thereby, the processing liquid supply part100supplies the processing liquid to the back surface side of the wafer (W). The processing liquid supply pipe (100a) is communicatively connected to a processing liquid supply port (91b) formed on an upper surface of the lift plate91.

The collection cup50has a drain cup51, a drain pipe52, an exhaust cup53and an exhaust pipe54. Further, the collection cup50has an opening55provided in an upper surface thereof. The collection cup50mainly plays a role of recovering a gas and a liquid discharged from a space surrounded by the holding part60and the rotating ring70.

The drain cup51receives a processing liquid guided by the rotating ring70. The drain pipe52is connected to a bottom part of the drain cup51, and discharges the processing liquid received by the drain cup51through a pipe of a drainage pipe group (not illustrated in the drawings).

The exhaust cup53is provided to be communicatively connected to the drain cup51outside or below the drain cup51.FIG. 2illustrates an example in which the exhaust cup53is provided to be communicatively connected to the drain cup51inside and below a peripheral edge of the drain cup51.

The exhaust pipe54is connected to a bottom part of the exhaust cup53, and exhausts a gas such as a nitrogen gas in the exhaust cup53through a pipe of an exhaust pipe group (not illustrated in the drawings).

The top plate110is movable up and down, and is provided so as to close the opening55provided in the upper surface of the collection cup50in a lowered state. Further, the top plate110is provided so as to cover the wafer (W) supported by the support pins (61b) from above when closing the opening55provided in the upper surface of the collection cup50.

A peripheral edge portion of the top plate110facing the peripheral edge portion of the wafer (W) supported by the support pins (61b) is provided projecting downward toward the wafer (W), and a gap (D1) is formed between the peripheral edge portion of the top plate110and the peripheral edge portion of the wafer (W). The gap (D1) is smaller than a distance between a center portion of the wafer (W) supported by the support pins (61b) and the top plate110.

The lift mechanism120includes an arm121and a lift driving part122. The lift driving part122is provided outside the collection cup50and is movable up and down. The arm121is provided to connect the top plate110and the lift driving part122. That is, the lift mechanism120raises or lowers the top plate110via the arm121by the lift driving part122.

The inert gas supply part130includes an inert gas supply pipe131and an inert gas supply source132. The inert gas supply part130supplies an inert gas to the upper surface side of the wafer (W).

The inert gas supply pipe131is provided extending inside the top plate110and the arm121, and one end of the inert gas supply pipe131is connected to the inert gas supply source132that supplies the inert gas at one end. Further, the other end of the inert gas supply pipe131is communicatively connected to an inert gas supply port (110a).

As illustrated inFIG. 2, by connecting the arm121at substantially a center of an upper surface of the top plate110, the inert gas supply port (110a) is formed at a center portion of a lower surface of the top plate110. Therefore, an inert gas can be supplied downward from a center of the top plate110, and a flow rate of the inert gas supplied to the wafer (W) can be uniformized along a circumferential direction.

The processing unit16includes a grounding part150and a variable resistance part160. One end part of the grounding part150is connected to the rotation mechanism, and the other end part of the grounding part150is connected to a ground potential. The variable resistance part160is a resistor provided in the grounding part150, and has a variable resistance.

Structure of Conduction Path

In the processing unit16according to the present embodiment, electricity generated in the wafer (W) is conducted to the ground potential via the holding part60, the rotation mechanism80, and the grounding part150, and thereby, the wafer (W) can be neutralized. Here, a structure of a conduction path for the electricity generated in the wafer (W) is specifically described.

A conduction path from the wafer (W) to the rotation shaft81is described with reference toFIGS. 3 and 4.FIG. 3is a plan view of the base plate61and the rotating ring70. Further,FIG. 4illustrates a structure of the conduction path from the wafer (W) to the rotation shaft81.

As illustrated inFIG. 3, the support pins (61b), for example, are formed of resin, and include two types of support pins: first support pins (61ba) and second support pins (61bb). When the first support pins (61ba) and the second support pins (61bb) are compared to each other, the first support pins (61ba) are formed of a material having higher conductivity than the second support pins (61bb).

The second support pins (61bb) are formed of a material having higher durability against chemicals than the first support pins (61ba). It is also possible that the second support pins (61bb) are formed of a non-conductive material for reasons such as that durability is regarded as important.

As illustrated by closed curves of broken lines inFIG. 3, for examples, three first support pins (61ba) are provided, and these first support pins (61ba) are positioned at substantially equal intervals, that is, at intervals of substantially 120 degrees, along a circumferential direction on a periphery edge of the base plate61.

Between each adjacent two of the first support pins (61ba), for example, three second support pins (61bb) are provided at substantially equal intervals along the circumferential direction on the peripheral edge of the base plate61. Therefore, a total of twelve support pins (61b) are positioned at intervals of substantially 30 degrees.

As indicated by arrows inFIG. 4, the electricity generated in the wafer (W) is conducted from the first support pins (61ba) that are formed of a conductive material to inside of the base plate61.

A conductive member (61f) is provided inside the base plate61. The conductive member (61f) is in contact with the first support pins (61ba). As a result, the electricity from the first support pins (61ba) is conducted to the conductive member (61f).

The conductive member (61f) extends to a vicinity of the rotation shaft81, and the electricity conducted to the conductive member (61f) is conducted to the rotation shaft81. The rotation shaft81is formed of a conductive material.

In the present embodiment, a conduction path from the first support pins (61ba) through the conductive member (61f) is formed, and the electricity generated in the wafer (W) is conducted from the first support pins (61ba) via the conductive member (61f) of the base plate61to the rotation shaft81.

In the present embodiment, three of the twelve support pins (61b) are the first support pins (61ba). However, the number or a ratio or the like of the first support pins (61ba) is not limited. The number of the first support pins (61ba) can be appropriately adjusted depending on whether or not the wafer (W) is appropriately neutralized.

A structure of a conduction path from the rotation shaft81to the ground potential is described with reference toFIG. 5.FIG. 5illustrates the structure of the conduction path from the rotation shaft81to the ground potential.

As illustrated inFIG. 5, the rotation mechanism80includes the rotation shaft81, the electric motor82, and a bearing83. Further, the electric motor82includes a housing (82a), a stator (82b) and a rotor (82c).

The housing (82a) is formed, for example, in a cylindrical shape and accommodates the stator (82b) and the rotor (82c) therein. The housing (82a) is formed of a conductive material. The stator (82b) is provided on an inner peripheral surface of the housing (82a). The rotor (82c) is positioned on an inner peripheral side of the stator (82b) and opposes the stator (82b) across a gap. The rotor (82c) is provided on an outer peripheral surface of the rotation shaft81, and opposes the stator (82b).

The bearing83is provided between the housing (82a) and the rotation shaft81and rotatably supports the rotation shaft81. The bearing83, for example, is a ball bearing and is formed of a conductive material.

The grounding part150, for example, is a ground wire. One end part of the grounding part150is connected to the housing (82a), and the other end part of the grounding part150is connected to the ground potential.

In the present embodiment, a conduction path from the rotation shaft81through the bearing83, the housing (82a) and the grounding part150is formed. Therefore, the electricity generated in the wafer (W), first, as illustrated inFIG. 4, is conducted from the first support pins (61ba) via the conductive member (61f) of the base plate61to the rotation shaft81, and thereafter, as illustrated inFIG. 5, is conducted from the rotation shaft81via the bearing83, the housing (82a) and the grounding part150to the ground potential. As a result, the wafer (W) can be neutralized.

In the present embodiment, the rotation mechanism80corresponds to an example of a “conduction path part”. However, the conduction path part is not necessarily required to be the rotation mechanism, but can be any object that is in contact with the holding part60and is formed of a conductive material. Therefore, the substrate processing apparatus and the substrate processing method disclosed in the present application can also be applied to a substrate processing apparatus that does not have a rotation mechanism.

Structure and Operation of Variable Resistance Part

Basically, it is preferable that a conduction path for neutralizing a substrate have a low resistance. However, in a series of substrate processing processes, it is also possible that, in some cases, it is not preferable to always keep the resistance of the conduction path low.

For example, in a case where a processing liquid supplied from the processing liquid supply port (91b) (seeFIG. 2) is itself charged, when the resistance of the conduction path is low (for example, is 0), an electric current flows at once to the wafer (W) and electric discharge occurs. As a result, it is possible that a pattern on the substrate is damaged. Although the wafer (W) has been subjected to an insulation treatment, the wafer (W) is slightly conductive. Therefore, an electric current flows at the moment when the processing liquid arrives at the wafer (W).

Therefore, in the processing unit16according to the present embodiment, the variable resistance part160is provided in the grounding part150, and the resistance of the conduction path can be varied by the variable resistance part160. Specifically, for a predetermined period of time from the start of supplying the processing liquid to the wafer (W), the resistance of the conduction path is increased to be higher than that in other periods of time by the variable resistance part160. Thereby, occurrence of the above-described electric discharge is suppressed.

An example of a structure of the variable resistance part160is described with reference toFIG. 6.FIG. 6illustrates an example of the structure of the variable resistance part160.

As illustrated inFIG. 6, the other end part of the grounding part150is branched to a first path (150a) and a second path (150b), which are each connected to the ground potential.

The variable resistance part160includes a first resistor161, a second resistor162, a first switch (SW1), and a second switch (SW2).

The first resistor161and the second resistor162, for example, are each a resistor having a certain resistance. The first resistor161is provided in the first path (150a), and the second resistor162is provided in the second path (150b). The resistance (second resistance) of the second resistor162is higher than the resistance (first resistance) of the first resistor161.

The first switch (SW1) and the second switch (SW2) switch a resistor connected to the grounding part150between the first resistor161and the second resistor162. The first switch (SW1) is provided in the first path (150a), and the second switch (SW2) is provided in the second path (150b). The first switch (SW1) and the second switch (SW2) are each turned on or off based on a control signal from the control unit18.

Timing for changing the resistance of the variable resistance part160is described with reference toFIG. 7.FIG. 7is a timing chart for describing an example of a resistance change process.

As illustrated inFIG. 7, after the wafer (W) is supported on the support pins (61b) of the holding part60, the control unit18controls the rotation mechanism80to rotate the wafer (W) at a first rotation speed (R1). Thereafter, the control unit18starts supplying a processing liquid from the processing liquid supply port (91b) to the back surface side of the wafer (W). The supplying of the processing liquid is continued for a processing liquid supply period (T).

Subsequently, when the processing liquid supply period (T) ends, the control unit18stops supplying the processing liquid from the processing liquid supply port (91b). Thereafter, the control unit18subjects the wafer (W) to shake-off drying (drying treatment) by increasing the rotation speed of the wafer (W) from R1to R2. When the drying treatment is finished, the control unit18stops the rotation of the wafer (W).

In such a series of substrate processing processes, the control unit18controls the variable resistance part160such that, during the processing liquid supply period (T), the resistance of the variable resistance part160in a first period (T1) immediately after the start is higher than the resistance of the variable resistance part160in a subsequent second period (T2).

Specifically, in the first period (T1), the control unit18connects the second resistor162having a relatively high resistance to the grounding part150. Then, when the first period (T1) ends, the control unit18connects the first resistor161having a lower resistance than the second resistor162to the grounding part150by bringing the second switch (SW2) to an open state and the first switch (SW1) to a closed state.

As a result, the resistance of the conduction path in the first period (T1) immediately after the supply of the processing liquid to the wafer (W) is started can be increased to be higher than that in the subsequent second period (T2). Therefore, even when a charged processing liquid arrives at the wafer (W), an electric current hardly flows in the wafer (W) and the electric discharge phenomenon is unlikely to occur. Therefore, a damage to a pattern due to the electric discharge can be prevented.

As described above, the support pins (61b) (seeFIG. 2) of the holding part60are formed using a conductive resin. For such a conductive resin, variation in resistance is large. Therefore, it is preferable that the second resistor162be a resistor having such a resistance that a sum of a predetermined value (such as an average value) as a resistance of each of the support pins (61b) and the resistance of the second resistor162is within a predetermined management value.

It is preferable that, even when power is turned off, one of the first path (150a) and the second path (150b) be connected to the ground potential. Here, basically, it is preferable that the resistance of the conduction path be as low as possible. Therefore, it is preferable that a contact point (b) be used for the first switch (SW1), and a contact point (a) be used for the second switch (SW2). The contact point (b) is a contact point that is usually in a closed state and is in an open state when an electrical signal is input. The contact point (a) is a contact point that is usually in an open state and is in a closed state when an electrical signal is input. Without being limited to this, it is also possible that the contact point (a) is used for the first switch (SW1), and the contact point (b) is used for the second switch (SW2).

Another structural example of the variable resistance part160and timing for changing the resistance of such a variable resistance part160are described with reference toFIGS. 8 and 9.FIG. 8illustrates another example of a structure of the variable resistance part160.FIG. 9is a timing chart for describing another example of a resistance change process.

As illustrated inFIG. 8, the variable resistance part160may be a variable resistor that changes a resistance according to a signal input from the control unit18.

As illustrated inFIG. 9, when the variable resistance part160is a variable resistor, the control unit18sets the resistance of the variable resistance part160to a relatively high first resistance before the start of a processing liquid supply process, and, after the supply of the processing liquid to the wafer (W) is started, gently decreases the resistance of the variable resistance part160during the processing liquid supply period (T). Even in such a case, it can be prevented that electric current flows at once to the wafer (W) immediately after the processing liquid arrives at the wafer (W). Therefore, a damage of a pattern due to electric discharge can be prevented.

First Modified Embodiment

In the above-described embodiment, electricity generated in the wafer (W) is released to the ground potential via the support pins (61b), the conductive member (61f), the rotation shaft81, the bearing83, the housing (82a) and the grounding part150.

However, a resistance of the bearing83increases as the rotation speed increases. This is because as the rotation speed increases, an oil film is formed stretching around balls of the bearing83so that the balls float from an orbital surface, and thereby, the balls are in a nearly insulated state. In this way, when the bearing83having a resistance that varies depending on the rotation speed is included in the conduction path, the resistance of the conduction path may become unstable.

Therefore, in a first modified embodiment, a structure of a conduction path that does not include the bearing83is described with reference toFIG. 10.FIG. 10illustrates the structure of the conduction path according to the first modified embodiment.

As illustrated inFIG. 10, the rotation mechanism80further includes a conductive container84, a conductive connection member85and an insulating support member86, and one end part of the grounding part150is connected to the container84.

A conductive liquid (L) is stored in the container84. As the liquid (L), an ionic liquid or a liquid metal can be used. The connection member85, for example, is formed of metal. One end part of the connection member85is in electrical contact with a circumferential surface of the rotation shaft81via a brush (85a), and the other end part of the connection member85is immersed in the liquid (L). The support member86supports the container84.

The conduction path according to the first modified embodiment is structured as described above. Electricity generated in the wafer (W) conducts to the ground potential via the support pins (61b), the conductive member (61f), the rotation shaft81, the connection member85, the liquid (L), the container84and the grounding part150.

The processing unit16according to the first modified embodiment is provided with an insulating bearing (83A) in place of the conductive bearing83.

In this way, by structuring a path that does not include the bearing (83A) as the conduction path for the electricity generated in the wafer (W), the resistance of the conduction path can be stabilized. Further, by using the insulating bearing (83A), conduction via an unintended path can be prevented.

Second Modified Embodiment

In the above-described first modified embodiment, the connection member85is brought into contact with the circumferential surface of the rotation shaft81. However, it is also possible that the connection member is connected to an end on an opposite side of a load side of the rotation shaft81. Such a second modified embodiment is described with reference toFIG. 11.FIG. 11illustrates a structure of a conduction path according to the second modified embodiment.

As illustrated inFIG. 11, a rotation shaft (81A) according to the second modified embodiment is a solid member. A connection member (85A) according to the second modified embodiment has a rod shape extending in a longitudinal direction, and is connected coaxially with the rotation shaft to an end on an opposite side of a load side of the rotation shaft (81A).

Even in the case of such a structure, similar to the first modified embodiment, the resistance of the conduction path can be stabilized.

Third Modified Embodiment

In the case where the connection member (85A) is coaxially rotated with the rotation shaft (81A) as in the above-described second modified embodiment, it is also possible that a conductive bearing is used in place of the container84. Such a third modified embodiment is described with reference toFIG. 12.FIG. 12illustrates a structure of a conduction path according to the third modified embodiment.

As illustrated inFIG. 12, the other end part of the connection member (85A) is rotatably supported by a conductive bearing87. The bearing87is supported by the support member86. The grounding part150is connected to the bearing87.

In this way, it is also possible that the electricity generated in the wafer (W) is conducted from the connection member (85A) to the grounding part150via the bearing87.

Fourth Modified Embodiment

The base plate61(seeFIG. 2) is formed of a resin. The resin tends to generate static electricity, and the generated static electricity may adversely affect the wafer (W). Therefore, it is preferable, for example, to periodically check whether or not the base plate61is not excessively charged.

Here, it is conceivable that, for example, a worker opens a panel (not illustrated in the drawings) and enters the processing unit16, and measures a charge amount of the base plate61by hand. However, an error involved in manual measurement is large. Further, by opening the panel, there is also a risk that foreign substance may enter the processing unit16. Further, depending on a size of the processing unit16, manual measurement itself may be difficult in some cases. On the other hand, it is also conceivable to provide a surface electrometer in the processing unit16, but it is not preferable due to problems such as chemical resistance.

Therefore, in a fourth modified embodiment, a method that allows the charge amount of the base plate61to be easily measured is described with reference toFIGS. 13-16.FIGS. 13 and 14are diagrams for describing content of a charge amount estimation process. Further,FIG. 15illustrates a structure of a measurement substrate; andFIG. 16illustrates a structure of a measurement part.

As illustrated inFIG. 13, in the charge amount estimation process according to the fourth modified embodiment, a measurement substrate (Wm) is used. The measurement substrate (Wm) is an insulating substrate. A conductive sheet (S) is affixed to a bottom surface of the measurement substrate (Wm).

Here, when the base plate61is charged, a positive charge is generated in the measurement substrate (Wm). In this state, as illustrated inFIG. 14, when the lift pins (91a) are raised and the measurement substrate (Wm) is separated from the support pins (61b), the measurement substrate (Wm) is positively charged. This charge amount, in principle, has the same value as an electrostatic induction potential received from the base plate61when the measurement substrate (Wm) is supported by the support pins (61b), and has an opposite polarity.

In a charge amount measurement process according to the fourth modified embodiment, after the lift pins (91a) are raised and the measurement substrate (Wm) is separated from the support pins (61b), the measurement substrate (Wm) is carried to a measurement part (to be described later) using the substrate transport device17(seeFIG. 1). The lift pins (91a) are insulating, and an end effector171and support parts (171a) are conductive.

As illustrated inFIG. 15, the substrate transport device17has, for example, the bifurcated end effector171. Multiple, for example, four support parts (171a) are provided on an upper surface of the end effector171, and the measurement substrate (Wm) is placed on the support parts (171a).

The conductive sheet (S) affixed to the lower surface of the measurement substrate (Wm) is affixed to a place other than places corresponding to the support parts (171a) of the end effector171. That is, the places that the support parts (171a) of the end effector171are in contact with are insulating. Therefore, a change in the charge amount of the measurement substrate (Wm) during carrying of the measurement substrate (Wm) can be suppressed.

Here, the charge amount estimation process is performed using the measurement substrate (Wm) that is obtained by affixing the conductive sheet (S) to the insulating substrate. However, in a case where a substrate itself is conductive, it is not necessary to use such a measurement substrate (Wm), and a charge amount measurement process may be performed, for example, using a product substrate. In this case, it is preferable that the support parts (171a) of the end effector171be insulating.

As illustrated inFIG. 16, the substrate processing system1has a measurement part190that measures the charge amount of the measurement substrate (Wm). The measurement part190is positioned, for example, in the delivery part14(seeFIG. 1). However, the positioning place of the measurement part190is not limited to the delivery part14. For example, it is also possible that a dedicated positioning place is provided in the processing station3, and the measurement part190is positioned in such a place.

The measurement part190includes, for example, support members191that support the measurement substrate (Wm) from below, a surface electrometer192that measures a surface potential of the measurement substrate (Wm) supported by the support members191, and a switch (SW3) for discharging. The switch (SW3) is in a closed state during measurement/ When the measurement is completed, the switch (SW3) is in an open state according to a control signal from the control unit18. When the switch (SW3) is in the open state, the measurement substrate (Wm) is neutralized.

When a measurement result is acquired from the measurement part190, the control unit18(seeFIG. 1) estimates the charge amount of the base plate61based on the acquired measurement result.

Specifically, as described above, in principle, the charge amount of the measurement substrate (Wm) measured by the measurement part190has the same value as and opposite polarity to the charge amount of the base plate61. Therefore, the control unit18estimates a charge amount having an opposite polarity to the acquired measurement result as the charge amount of the base plate61.

In this way, by estimating the charge amount of the base plate61based on the measurement result of the measurement part190, the charge amount of the base plate61can be measured using a simple method without depending on a manual operation of a worker and without having problems such as chemical resistance.

The charge amount of the measurement substrate (Wm) is actually smaller than the charge amount of the base plate61by an amount corresponding to a distance away from the support pins (61b). Therefore, the control unit18may estimate the charge amount of the base plate61by taking into account the decrease in the charge amount due to that the measurement substrate (Wm) is separated away from the support pins (61b). As a result, estimation accuracy of the charge amount of the base plate61can be improved.

For example, when the base plate61is charged to −6 kV, in principle, the measurement substrate (Wm) is charged to +6 kV. However, the charge amount of the measurement substrate (Wm) decreases by an amount corresponding to a rising distance of the measurement substrate (Wm) from the support pins (61b). In a case that the measurement substrate (Wm) is charged to +5 kV, the control unit18adds +1 kV, which is a correction amount corresponding to the rising distance of the measurement substrate (Wm) from the support pins (61b), to +5 kV, which is the measurement result of the measurement part190, to obtain a total of +6 kV, and thereby, the control unit18can estimate the charge amount of the base plate61to be −6 kV.

The correction amount, for example, can be stored in the memory19in association with the rising distance of the measurement substrate (Wm) from the support pins (61b). The control unit18can acquire from the memory19the correction amount corresponding to the rising distance of the measurement substrate (Wm) from the support pins (61b) in the charge amount estimation process, and can correct the measurement result using the acquired correction amount. It is also possible that the control unit18obtains the correction amount corresponding to the rising distance of the measurement substrate (Wm) from the support pins (61b) by calculation.

When the estimated charge amount of the base plate61exceeds a predetermined threshold, the control unit18may perform a predetermined abnormality handling process. For example, as an abnormal handling process, the control unit18can notify that the charge amount of the base plate61exceeds the threshold by using a lamp or a speaker (not illustrated in the drawings) or can stop the substrate processing.

Here, an example of a case is described where, after the measurement substrate (Wm) held by the holding part60is raised by the lift pins (91a), the substrate transport device17receives the measurement substrate (Wm) from the lift pins (91a) and carries the measurement substrate (Wm) to the measurement part190. However, without being limited to this, it is also possible that the substrate transport device17directly receives the measurement substrate (Wm) from the holding part60and carries the measurement substrate (Wm) to the measurement part190. Also in this case, the charge amount of the base plate61can be estimated in the same way as described above.

Fifth Modified Embodiment

As illustrated inFIG. 2, the peripheral edge portion of the top plate110facing the peripheral edge portion of the wafer (W) supported by the support pins (61b) is provided projecting downward toward the wafer (W), and the gap (D1) is formed between the peripheral edge portion of the top plate110and the peripheral edge portion of the wafer (W).

The gap (D1) is smaller than the distance between the center portion of the wafer (W) supported by the support pins (61b) and the top plate110. Therefore, a flow velocity of an airflow flowing from the center portion of the wafer (W) to the peripheral edge portion may decrease in the gap (D1). Further, frictional resistance due to viscosity of the airflow is also likely to occur.

Therefore, in a fifth modified embodiment, a structure for suppressing turbulence of the airflow in the gap (D1) is described with reference toFIGS. 17 and 18.FIG. 17is an enlarged schematic view of a rectifier.FIG. 18is a schematic cross-sectional view of the rectifier.FIG. 17is an enlarged schematic view of a portion corresponding to an H portion inFIG. 2.

As illustrated inFIG. 17, the top plate110has a rectifier180in a portion corresponding to the gap (D1).

The rectifier180has multiple recesses181on a lower surface, that is, a surface facing the peripheral edge portion of the wafer (W). In this way, since the lower surface of the rectifier180has a so-called dimple shape, the frictional resistance in the gap (D1) can be reduced.

Here, the airflow from the central portion of the wafer (W) to the peripheral edge portion varies, for example, depending on a displacement of processing unit16or the rotation speed of the wafer (W). Therefore, the rectifier180is structured to be able to adjust strength of a rectification effect according to variation of the airflow.

Specifically, as illustrated inFIG. 18, the rectifier180has a hollow main body182. A fluid supply part184is connected to the main body182via a supply pipe183. The fluid supply part184supplies a fluid to an inner space of the main body182. Further, the fluid supply part184can also suck the fluid supplied to the inner space of the main body182. The fluid supplied from the fluid supply part184is, for example, an inert gas such as a nitrogen gas or an argon gas. However, it is also possible that the fluid is a liquid such as pure water.

The above-described recesses181each include an opening (181a) formed on a lower surface of the main body182and a stretchable film (181b) affixed to the opening (181a).

The rectifier180is structured as described above, and can adjust concavity or convexity of the films (181b) of the recesses181by varying a pressure in the inner space of the main body182by supplying a fluid from the fluid supply part184to the inner space of the main body182or sucking the fluid from the inner space of the main body192according to the control unit18.

As a result, by adjusting depths of the recesses181according to situations where the airflow changes such as the displacement and the rotation speed, the airflow flowing through the gap (D1) can be appropriately rectified.

In the processing unit16, when the processing liquid supply process is completed and the processing proceeds to the drying treatment, the rotation speed of the wafer (W) is increased (seeFIG. 7). Therefore, when the processing proceeds to the drying treatment, the control unit18controls the fluid supply part184to suck the fluid from the inner space of the main body182to deepen the recesses181. As a result, the airflow flowing through the gap (D1) during the drying treatment can be appropriately rectified.

When multiple processing liquids are used, there are cases where the displacement is switched for each processing liquid. Therefore, the control unit18may control the fluid supply part184to adjust the depths of the recesses181when switching of processing liquids. For example, in a case where a rinse treatment using pure water is performed after a processing liquid is supplied and thereafter a replacement process using IPA (isopropyl alcohol) is performed, when the processing proceeds from the rinse treatment to the replacement process, the displacement may be reduced. In this case, when the processing proceeds from the rinse process to the replacement process, the control unit18controls the fluid supply part184to supply a fluid to the inner space of the main body182to shallow the recesses181. As a result, the airflow flowing through the gap (D1) during the replacement process can be appropriately rectified.

The processing unit16(an example of a substrate processing apparatus) according to the present embodiment includes the conductive holding part60, the conductive rotation mechanism80(an example of a conduction path part), the processing liquid supply part100(an example of a supply part), the grounding part150, and the variable resistance part160. The holding part60holds the wafer (W) (an example of a substrate). The rotation mechanism80is in contact with the holding part60, and is formed of a conductive material. The processing liquid supply part100supplies a processing liquid to the wafer (W) held by the holding part60. One end part of the grounding part150is connected to the rotation mechanism80, and the other end part of the grounding part150is connected to a ground potential. The variable resistance part160is provided in the grounding part150, and has a variable resistance.

Therefore, according to the processing unit16of the present embodiment, the resistance of the conduction path for the electricity generated in the wafer (W) can be varied according to a substrate processing situation. Therefore, in a series of substrate processing processes, the wafer (W) can be properly protected from an electrical damage.

The processing unit16has the control unit18that controls the variable resistance part160. The control unit18controls the variable resistance part160such that, during the processing liquid supply period (T), which is a period from when the supply of the processing liquid to the wafer (W) is started to when the supply of the processing liquid to the wafer (W) is finished, the resistance of the variable resistance part160immediately after the start of this period is higher than the resistance of the variable resistance part160thereafter.

As a result, it is possible to suppress occurrence of the electric discharge phenomenon caused by that a charged processing liquid arrives at the wafer (W) when the resistance of the conduction path is low. Therefore, in a series of substrate processing processes, the wafer (W) can be properly protected from an electrical damage.

The variable resistance part160includes the first resistor161, the second resistor162, the first switch (SW1), and the second switch (SW2) (an example of a switching part). The first resistor161has the first resistance. The second resistor162has the second resistance that is higher than the first resistance. The first switch (SW1) and the second switch (SW2) switch the resistor connected to the grounding part150between the first resistor161and the second resistor162. Further, the control unit18controls the first switch (SW1) and the second switch (SW2) to connect the second resistor162to the grounding part150immediately after the start of the processing liquid supply period (T), and thereafter, connect the first resistor161to the grounding part150.

As a result, the resistance of the conduction path in the period immediately after the supply of the processing liquid to the wafer (W) is started can be increased to be higher than that in the subsequent period. Therefore, even when a charged processing liquid arrives at the wafer (W), an electric current hardly flows in the wafer (W) and the electric discharge phenomenon is unlikely to occur. Therefore, damage to a pattern due to the electric discharge can be prevented. Therefore, in a series of substrate processing processes, the wafer (W) can be properly protected from an electrical damage.

The variable resistance part160may be a variable resistor that changes a resistance according to a signal input from the control unit18. Even in such a case, in a series of substrate processing processes, the wafer (W) can be properly protected from an electrical damage.

The rotation mechanism80includes the conductive rotation shaft (81,81A), the electric motor82, the conductive container84, and the conductive connection member (85,85A). The rotation shaft (81,81A) is in electrical contact with the holding part60and rotatably supports the holding part60. The electric motor82rotates the rotation shaft (81,81A). The conductive liquid (L) is stored in the container84. One end part of the connection member (85,85A) is in electrical contact with the rotation shaft (81,81A), and the other end part of the connection member (85,85A) is immersed in the liquid (L). Further, one end part of the grounding part150is connected to the container84in the rotation mechanism80.

The connection member (85A) has a rod shape extending in the longitudinal direction, and is connected coaxially with the rotation shaft to an end on an opposite side of a load side of the rotation shaft (81A).

In this way, by structuring a path that does not include the bearing as the conduction path for the electricity generated in the wafer (W), the resistance of the conduction path can be stabilized.

The rotation mechanism80includes the insulating bearing (83A) that is provided between the electric motor82and the rotation shaft (81,81A) and rotatably supports the rotation shaft (81,81A). In this way, by using the insulating bearing (83A), conduction via an unintended path can be prevented.

The processing unit16includes the measurement part190, the substrate transport device17(an example of a substrate transport part, and the control unit18(an example of an estimation part). The measurement part190measures a charge amount of the wafer (W). The substrate transport device17passes the wafer (W) held by the holding part60to the measurement part190. The control unit18estimates a charge amount of the holding part60based on a measurement result of the measurement part190.

In this way, by estimating the charge amount of the holding part60based on the measurement result of the measurement part190, the charge amount of the holding part60can be measured using a simple method without depending on a manual operation of a worker and without having problems such as chemical resistance.

The control unit18estimates the charge amount of the holding part60using the measurement result of the measurement part190and a correction amount that corresponds to an amount of displacement of the measurement substrate (Wm) from the holding part60due to the cylinder mechanism (92a) when the measurement substrate (Wm) is passed to the substrate transport device17. As a result, estimation accuracy of the charge amount of the holding part60can be improved.

A substrate processing apparatus processes a substrate such as a semiconductor wafer or a glass substrate by supplying a processing liquid to the substrate.

In a substrate processing apparatus of this kind, for example, when a processing liquid flows on a surface of a substrate, static electricity may be generated due to frictional charging or the like. Therefore, in the substrate processing apparatus described in Japanese Patent Laid-Open Publication No. 2003-092343, by structuring at least a portion of a holding part using a conductive material, static electricity is prevented from staying in the holding part, and a substrate held by the holding part is prevented from being affected by the static electricity.

Basically, it is preferable that a conduction path for neutralizing a substrate have low a resistance. However, depending on a situation of a series of substrate processing processes, in some cases it is not preferable for the conduction path to have a low resistance. For example, when the resistance of the conduction path is too low, electric current flows to the substrate at once, and a pattern on the substrate may be damaged.

A substrate processing apparatus and a substrate processing method according to embodiments of the present invention can properly protect a substrate from an electrical damage.

A substrate processing apparatus according to an embodiment of the present invention includes a conductive holding part, a conduction path part, a supply part, a grounding part, and a variable resistance part. The holding part holds a substrate. The conduction path part is in contact with the holding part and is formed of a conductive material. The supply part supplies a processing liquid to the substrate held by the holding part. One end part of the grounding part is connected to the conduction path part, and the other end part of the grounding part is connected to a ground potential. The variable resistance part is provided in the grounding part, and has a variable resistance.

According to an embodiment of the present invention, the substrate can be properly protected from an electrical damage.