JP7403362B2 - Substrate processing method and substrate processing apparatus - Google Patents

Description

The present application relates to a substrate processing method and a substrate processing apparatus.

Conventionally, a substrate processing apparatus has been proposed that supplies a processing liquid to a substrate and performs processing on the substrate based on the processing liquid (for example, Patent Document 1). In Patent Document 1, a substrate processing apparatus includes a holding section, a conduction path section, a grounding section, a variable resistance section, and a supply section. The holding portion is electrically conductive and holds the substrate. The conduction path portion is provided between the holding portion and the grounding portion and comes into contact with them. The variable resistance section is provided at the ground section. The supply unit supplies the processing liquid to the substrate held by the holding unit.

In Patent Document 1, the problem is that a large current flows between the processing liquid and the substrate when the processing liquid is electrically charged. Specifically, the problem is that the moment the processing liquid contacts the substrate, a large current flows from the processing liquid to the grounding section via the substrate and the conduction path in this order, causing electrical discharge on the substrate. .

In order to solve this problem, in Patent Document 1, the resistance value of the variable resistance section is made higher for a predetermined period after the supply of processing liquid to the substrate is started than for other periods thereafter. This makes it difficult for current to flow from the processing liquid to the ground portion via the substrate and the conduction path portion for a predetermined period of time, thereby reducing the occurrence of discharge.

Unexamined Japanese Patent Publication No. 2017-183389

As mentioned above, Patent Document 1 considers the relationship between the resistance value of the path between the substrate and the grounding part and the current flowing from the charged processing liquid to the substrate, and by increasing the resistance value for a predetermined period, The current is reduced. However, Patent Document 1 does not consider the relationship between the resistance value and in-plane variations of the substrate due to the processing liquid.

There are various treatments for substrates, one example of which is an etching treatment for etching an oxide film on the substrate. For example, dilute hydrofluoric acid can be used as the chemical solution for etching the oxide film. By supplying this dilute hydrofluoric acid to the main surface of the substrate, the oxide film formed on the main surface of the substrate can be etched.

Here, it is assumed that the substrate is held by a plurality of chuck pins. The plurality of chuck pins are arranged at regular intervals along the periphery of the substrate, and abut against the periphery of the substrate to hold the substrate. The plurality of chuck pins are made of a low resistance material, and the resistance value of the path between the substrate held by the plurality of chuck pins and the ground portion is high. Specifically, the resistance value of the conduction path is lower than when the chuck pin is made of a high resistance material.

In this case, a difference in etching rate was observed between the first region of the main surface of the substrate near the chuck pin and the second region away from the chuck pin (for example, the central region of the substrate). Specifically, the etching rate in the first region was higher than the etching rate in the second region. In other words, the in-plane variation in etching with respect to the main surface of the substrate has increased.

Furthermore, an example of a process for a substrate is a process for forming a chemical oxide film on a silicon substrate. A mixed solution of sulfuric acid and hydrogen peroxide (SPM) may be used as a chemical solution to form a chemical oxide film on silicon. In this case, if the resistance value of the path is low, a difference may occur in the formation rate of the oxide film between the first region and the second region of the main surface of the substrate. Specifically, the formation rate of the oxide film in the first region is higher than the formation rate of the oxide film in the second region, and the thickness of the oxide film in the first region is greater than the thickness of the oxide film in the second region. It gets thicker. In other words, the in-plane variation in film thickness with respect to the main surface of the substrate has increased.

As described above, when the resistance value of the path is low, the in-plane variation in the degree of processing on the main surface of the substrate becomes large. Note that in-plane variations in processing due to the low resistance value of the path may occur not only with the above-mentioned chemical solution but also with other chemical solutions.

Further, after the chemical solution treatment, a rinsing process is performed to wash away the chemical solution. In the rinsing process, a rinsing liquid is supplied to the main surface of the substrate, and the chemical solution on the main surface of the substrate is washed away with the rinsing liquid. After that, the substrate is dried. If the resistance value of the path is high, the substrate may become electrically charged due to friction between the rinsing liquid and the substrate during the rinsing process. If the substrate is charged, there is a possibility that problems may occur in various steps after drying the substrate.

Therefore, the present application provides a technique that can perform a chemical liquid process with high in-plane uniformity while reducing the charge on the substrate in the subsequent rinsing process.

A first aspect of the substrate processing method includes a holding step of holding the peripheral edge of the substrate with a plurality of chuck pins, a potential measuring step of measuring the surface potential of the substrate, and a main surface of the substrate held by the chuck pins. a rotation step of rotating the substrate around a rotation axis perpendicular to the substrate; a chemical solution step of supplying a chemical solution to the main surface of the rotating substrate; and after the chemical solution step, the substrate held by the chuck pin. a resistance value changing step of reducing the resistance value of a conductive path between the substrate and ground; and a rinsing step of supplying a rinsing liquid to the main surface of the rotating substrate while the resistance value of the conductive path is reduced. Equipped with.
A second aspect of the substrate processing method is the substrate processing method according to the first aspect, which is performed when the surface potential measured in the potential measurement step is equal to or higher than a reference value, and is performed when the substrate is rotated. The method further includes a static eliminating step of supplying a static eliminating liquid to the main surface of the device.

A third aspect of the substrate processing method is the substrate processing method according to the first or second aspect, in which the chemical solution contains SPM or hydrofluoric acid.

A fourth aspect of the substrate processing method is the substrate processing method according to any one of the first to third aspects, wherein in the chemical liquid step, a plurality of first chuck pins among the chuck pins are used to treat the substrate. and in the resistance value changing step, the chuck pins that hold the substrate are switched from the first chuck pins to a plurality of second chuck pins having a smaller resistance value than the first chuck pins.

A fifth aspect of the substrate processing method is the substrate processing method according to the fourth aspect, wherein the resistance value of the first chuck pin is 1 MΩ or more, and the resistance value of the second chuck pin is 10Ω or less. .

A sixth aspect of the substrate processing method is the substrate processing method according to any one of the first to fifth aspects, wherein in the chemical liquid step, the resistance value of the variable resistor between the chuck pin and the ground is 1 resistance value, and in the resistance value changing step, the resistance value of the variable resistor is reduced to a second resistance value smaller than the first resistance value.

A seventh aspect of the substrate processing method includes a holding step of holding the peripheral edge of the substrate with a plurality of chuck pins, and rotating the substrate around a rotation axis perpendicular to the main surface of the substrate held by the chuck pins. a rotation step for supplying a chemical solution to the main surface of the rotating substrate; and after the chemical step, a resistance value of a conductive path between the substrate held by the chuck pin and ground is determined. and a rinsing step of supplying a rinsing liquid to the main surface of the rotating substrate in a state where the resistance value of the conduction path is reduced, and before the chemical liquid step, the The method further includes a static eliminating step of supplying static eliminating liquid to the substrate held by the chuck pins.

An eighth aspect of the substrate processing method is the substrate processing method according to the seventh aspect, in which the static electricity removal is performed in a state where the resistance value of the conductive path is higher than the resistance value of the conductive path in the rinsing step. Start the process.

A ninth aspect of the substrate processing method is the substrate processing method according to the eighth aspect, in which the resistance value of the conductive path is reduced during the static elimination step.

A tenth aspect of the substrate processing method is the substrate processing method according to the eighth aspect, further comprising a current measurement step of measuring the current flowing through the conduction path, which is performed in parallel with the static elimination step, and the step of measuring the current flowing through the conduction path. In the static elimination step, when the current falls below a second current reference value, the resistance value of the conduction path is reduced.

An eleventh aspect of the substrate processing method is the substrate processing method according to any one of the seventh to ninth aspects, including a potential measuring step of measuring the surface potential of the substrate before the static elimination step. Further comprising: determining the resistance value of the conduction path in the static elimination step to be a third resistance value when the surface potential is larger than the potential reference value; The method further includes a step of determining a resistance value of the conduction path in the static elimination step to a fourth resistance value lower than the third resistance value.

A twelfth aspect of the substrate processing method is the substrate processing method according to any one of the seventh to ninth aspects, including a potential measuring step of measuring the surface potential of the substrate before the static eliminating step. Further comprising: supplying a first static eliminating liquid as the static eliminating liquid in the static eliminating step when the surface potential is greater than the potential reference value; and supplying a first static eliminating liquid as the static eliminating liquid when the surface potential is smaller than the potential reference value; The method further includes a step of supplying, as the static eliminating liquid, a second static eliminating liquid having a lower specific resistance value than the first static eliminating liquid.

A thirteenth aspect of the substrate processing method is the substrate processing method according to any one of the seventh to ninth and eleventh aspects, wherein in the static eliminating step, after supplying a first static eliminating liquid as the static eliminating liquid. , a second static eliminator having a lower specific resistance value than the first static eliminator is supplied to the substrate as the static eliminator.

A fourteenth aspect of the substrate processing method is the substrate processing method according to the thirteenth aspect, further comprising a current measurement step of measuring the current flowing through the conduction path, which is performed in parallel with the static elimination step, and the step of measuring the current flowing through the conduction path. In the static elimination step, when the current falls below a current reference value, the supply of the first static elimination liquid is stopped, and the supply of the second static elimination liquid is started.

A fifteenth aspect of the substrate processing method is the substrate processing method according to any one of the seventh to ninth and eleventh to thirteenth aspects, wherein the method is performed in parallel with the static elimination step, and the conductive path is The method further includes a current measuring step of measuring a flowing current, and in the static eliminating step, when the current falls below a current reference value, supply of the static eliminating liquid is ended.

A 16th aspect of the substrate processing method is the substrate processing method according to any one of the 7th to 15th aspects, further comprising a dry step of performing dry etching on the substrate before the static elimination step. Be prepared.

A seventeenth aspect of the substrate processing method is the substrate processing method according to any one of the first to sixteenth aspects, in which silicon is exposed on the main surface of the substrate.

A first aspect of the substrate processing apparatus is a substrate processing apparatus, which has a holding position where the substrate is held by contacting the periphery of the substrate, and a release position where the substrate is released from being held by moving away from the periphery of the substrate. a plurality of first chuck pins that move between a plurality of first chuck pins, a holding position that has a resistance value smaller than that of the first chuck pins and holds the substrate by contacting the periphery of the substrate, and a holding position that is separated from the periphery of the substrate. a substrate holder including a plurality of second chuck pins that move between release positions for releasing the holding of the substrate; a rotation mechanism that rotates the substrate holding unit; a chuck driving unit that independently drives the first chuck pin and the second chuck pin; and supplying a chemical solution to the main surface of the substrate held by the substrate holding unit. a chemical liquid nozzle; a rinse nozzle that supplies a rinsing liquid to the main surface of the substrate held by the substrate holder ; a surface potential sensor that measures the surface potential of the substrate; a control unit that determines whether or not to supply the substrate based on the surface potential measured by the surface potential sensor ; The chemical solution is supplied from the chemical solution nozzle to the main surface of the substrate, and the rinse liquid is supplied from the rinse nozzle to the main surface of the substrate while the substrate is held by the second chuck pin.

A second aspect of the substrate processing apparatus is the substrate processing apparatus according to the first aspect, comprising: a static elimination nozzle that supplies a static elimination liquid to the main surface of the substrate held by the substrate holder; The device further includes a current sensor that measures a current flowing through a conductive path between the device and ground.

According to the first to third aspects and the seventeenth aspect of the substrate processing method, the chemical solution is supplied to the main surface of the substrate while the resistance value of the conduction path is high. Therefore, in-plane variations in the chemical liquid process due to the low resistance value of the conduction path can be reduced. Further, the rinsing liquid is supplied to the main surface of the substrate in a state where the resistance value of the conduction path is low. Therefore, charging of the substrate due to friction between the substrate and the rinsing liquid, etc. can be reduced.

According to the fourth and fifth aspects of the substrate processing method, the resistance value between the substrate holder and the ground can be changed with a simple configuration.

According to the sixth aspect of the substrate processing method, since a variable resistor is used, the resistance value of the conduction path can be finely adjusted.

According to the seventh aspect of the substrate processing method, the substrate can be neutralized before the chemical solution is supplied. Therefore, a large current between the chemical solution and the substrate due to charging of the substrate can be reduced or avoided.

According to the eighth aspect of the substrate processing method, even if the amount of charge on the substrate is large, the charge on the substrate can be eliminated while reducing the current between the static eliminating liquid and the substrate.

According to the ninth aspect of the substrate processing method, the resistance value of the conductive path is high at the initial stage of the static elimination process. Therefore, it is possible to gradually remove static electricity from the substrate while reducing or avoiding a large current between the substrate and the conduction path. On the other hand, in the latter stage of the static elimination process when the substrate has been neutralized to some extent, even if the resistance value of the conduction path is reduced, as large a current as in the initial stage does not flow. Therefore, in the latter stage of the static elimination process, the resistance value of the conduction path is reduced. Thereby, the speed of charge removal from the substrate can be improved.

According to the tenth aspect of the substrate processing method, the timing for reducing the resistance value of the conduction path is determined based on the current that reflects the amount of charge on the substrate. Therefore, the resistance value of the conduction path can be more reliably reduced in a state where the amount of charge is reduced to such an extent that a large current will not flow even if the resistance value of the conduction path is reduced.

According to the eleventh aspect of the substrate processing method, the amount of charge on the substrate is measured before the chemical step on the substrate, and the resistance value of the conductive path in the charge removal step is determined according to the amount of charge. According to this, when the amount of charge is large, the substrate can be neutralized while the resistance value of the conduction path is high, and damage to the substrate can be more reliably reduced or avoided. On the other hand, when the amount of charge is small, the substrate can be neutralized while the resistance value of the conduction path is low, and damage to the substrate can be more reliably reduced or avoided while the substrate can be neutralized more quickly.

According to the twelfth aspect of the substrate processing method, the amount of charge on the substrate is measured before the step of applying a chemical solution to the substrate, and the charge eliminating liquid used in the step of removing the charge is determined according to the amount of charge. According to this, when the amount of charge is large, the substrate can be neutralized with the first static eliminating liquid having a high specific resistance value, and damage to the substrate can be more reliably reduced or avoided. On the other hand, when the amount of charge is small, the second static eliminator having a low specific resistance value can eliminate static electricity from the substrate, and damage to the substrate can be more reliably reduced or avoided while static electricity can be removed from the substrate more quickly.

According to the thirteenth aspect of the substrate processing method, the first static eliminating liquid having a high specific resistance value is supplied at the initial stage of the static eliminating process. Therefore, it is possible to gradually eliminate static electricity from the substrate while reducing or avoiding a large current between the processing liquid and the substrate. On the other hand, in the latter stage of the static elimination process when the substrate has been neutralized to some extent, even if the second static elimination liquid with a low specific resistance value is supplied, as large a current as in the initial stage does not flow. Therefore, in the latter stage of the static elimination process, the second static elimination liquid is supplied. Thereby, the speed of charge removal from the substrate can be improved.

According to the fourteenth aspect of the substrate processing method, the timing of switching the static eliminating liquid is determined based on the current that reflects the amount of charge on the substrate. Therefore, the static eliminator can be switched to the second static eliminator more reliably in a state where the amount of charge is reduced to such an extent that a large current does not occur even if the second static eliminator having a small specific resistance value is supplied.

According to the fifteenth aspect of the substrate processing method, the timing to end the static elimination process is determined based on the current that reflects the amount of charge on the substrate. Therefore, the static elimination step can be completed more reliably in a state where the amount of charge is reduced.

According to the sixteenth aspect of the substrate processing method, the substrate is charged.

According to the first aspect of the substrate processing apparatus, the resistance value between the chuck pins that hold the substrate and the ground can be switched.

According to the second aspect of the substrate processing apparatus, the amount of charge on the substrate can be indirectly measured by current measurement.

Objects, features, aspects, and advantages of the technology disclosed herein will become more apparent from the detailed description and accompanying drawings set forth below.

FIG. 1 is a plan view schematically showing an example of the configuration of a substrate processing system. 1 is a diagram schematically showing an example of the configuration of a substrate processing apparatus. FIG. 2 is a plan view schematically showing an example of the configuration of a substrate holding section. FIG. 2 is a plan view schematically showing an example of the configuration of a substrate holding section. FIG. 2 is a functional block diagram schematically showing an example of the configuration of a control section. 2 is a flowchart showing an example of the operation of the substrate processing apparatus (first substrate processing). It is a graph which shows an example of the resistance value of the conduction path according to each process. FIG. 3 is a diagram schematically showing another example of the configuration of the substrate processing apparatus. FIG. 3 is a diagram schematically showing another example of the configuration of the substrate processing apparatus. It is a flowchart which shows another example (2nd substrate processing) of operation|movement of a substrate processing apparatus. It is a graph which shows an example of the resistance value of the conduction path according to each process. It is a flowchart which shows another example (3rd substrate processing) of operation of a substrate processing apparatus. It is a graph which shows an example of the resistance value of the conduction path according to each process. FIG. 3 is a diagram schematically showing another example of the configuration of the substrate processing apparatus. It is a flowchart which shows roughly an example of a static elimination process. It is a flowchart which shows another example of operation of a substrate processing apparatus. It is a flowchart which shows another example of operation|movement of a 4th board|substrate process. It is a graph which shows an example of the resistance value of the conduction path according to each process.

Embodiments will be described below with reference to the accompanying drawings. Note that the drawings are shown schematically, and for convenience of explanation, structures are omitted or simplified as appropriate. Further, the sizes and positional relationships of the structures shown in the drawings are not necessarily accurately described and may be changed as appropriate.

In addition, in the following description, similar components are shown with the same reference numerals, and their names and functions are also the same. Therefore, detailed descriptions thereof may be omitted to avoid duplication.

In addition, in the description below, even if ordinal numbers such as "first" or "second" are used, these terms are used to make it easier to understand the content of the embodiments. They are used for convenience and are not limited to the order that can occur based on these ordinal numbers.

Expressions indicating relative or absolute positional relationships (e.g., "in one direction," "along one direction," "parallel," "perpendicular," "centered," "concentric," "coaxial," etc.) are used unless otherwise specified. It does not only strictly represent the positional relationship, but also represents the state of relative displacement in terms of angle or distance within a range where tolerance or the same level of function can be obtained. Unless otherwise specified, expressions indicating equal states (e.g., "same," "equal," "homogeneous," etc.) do not only mean quantitatively strictly equal states, but also mean that tolerances or functions of the same degree can be obtained. It also represents a state in which a difference exists. Unless otherwise specified, expressions that indicate a shape (e.g., "quadrangular shape" or "cylindrical shape") do not only strictly represent the shape geometrically, but also include, to the extent that the same degree of effect can be obtained, e.g. Shapes with irregularities, chamfers, etc. are also represented. The expressions "comprising," "comprising," "comprising," "containing," or "having" one component are not exclusive expressions that exclude the presence of other components. The expression "at least one of A, B, and C" includes only A, only B, only C, any two of A, B, and C, and all of A, B, and C.

<Schematic configuration of substrate processing system>
FIG. 1 is a plan view schematically showing an example of the configuration of a substrate processing system 100 that functions as a substrate cleaning apparatus. As shown in FIG. 1, the substrate processing system 100 is a single-wafer type device that can be used, for example, to remove organic dust attached to the surface of a semiconductor substrate (wafer) 9, which is an example of a substrate. It is. Examples of organic waste include, for example, unnecessary resist remaining on the surface of the substrate 9 after an ion implantation process for implanting impurities into the surface of the substrate 9, or resist on the outer periphery of the surface of the substrate 9. This includes organic dust and the like originating from resists adhering to the vicinity.

The substrate processing system 100 includes a load port LP as a container holding mechanism that holds a plurality of carriers C as containers, and a plurality of (12 in this embodiment) processing units 110 that process the substrates 9. include. Specifically, for example, three sets of processing units 110, each consisting of four processing units 110 arranged in a plane, are arranged so as to be stacked in the vertical direction.

The substrate processing system 100 further includes, for example, an indexer robot IR, a center robot CR, and a control unit 6. The indexer robot IR can, for example, transport the substrate 9 between the load port LP and the center robot CR. The center robot CR can transport the substrate 9 between the indexer robot IR and each processing unit 110, for example. The control unit 6 can control, for example, the operation of each unit included in the substrate processing system 100 and the opening and closing of valves.

Here, as shown in FIG. 1, the load port LP and each processing unit 110 are arranged at intervals in the horizontal direction. In the load port LP, a plurality of carriers C that accommodate a plurality of substrates 9 are arranged along a horizontal arrangement direction D when viewed from above. The load port LP functions as a loading section into which the substrate 9 is loaded. Here, the indexer robot IR can, for example, transport a plurality of substrates 9 one by one from the carrier C to the substrate platform PASS, and also transport a plurality of substrates 9 from the substrate platform PASS to the carrier C. Can be transported one by one. The substrate platform PASS includes a platform on which the substrate 9 is placed.

For example, the central robot CR can transport a plurality of substrates 9 one by one from the substrate platform PASS to each processing unit 110, and can also transport a plurality of substrates 9 from each processing unit 110 to the substrate platform PASS. can be transported one by one. Further, for example, the central robot CR can transport the substrate 9 between the plurality of processing units 110 as necessary. The indexer robot IR, the substrate platform PASS, and the center robot CR function as a substrate transfer section that receives the substrate 9 from the loading section (load port LP) and transfers it to the processing unit 110.

In the example of FIG. 1, the indexer robot IR has a hand H that is U-shaped in plan view. Here, the indexer robot IR has two hands H. The two hands H are placed at different heights. Each hand H can support the substrate 9 in a horizontal position. The indexer robot IR can move the hand H in the horizontal and vertical directions. Furthermore, the indexer robot IR can change the direction of the hand H by rotating (rotating) about an axis along the vertical direction. The indexer robot IR moves along the arrangement direction D on a path passing through the delivery position (the position where the indexer robot IR is drawn in FIG. 1). The delivery position is a position where the indexer robot IR and the substrate platform PASS face each other in a direction perpendicular to the arrangement direction D when viewed from above. The indexer robot IR can have a hand H facing each of an arbitrary carrier C and a substrate platform PASS. Here, for example, by moving the hand H, the indexer robot IR can perform a carry-in operation of carrying the substrate 9 into the carrier C and a carry-out operation of carrying the substrate 9 out of the carrier C. Further, for example, by moving the hand H at the delivery position, the indexer robot IR performs a carry-in operation of carrying the substrate 9 into the substrate platform PASS, and a carrying-out operation of carrying out the substrate 9 from the substrate platform PASS. be able to.

In the example of FIG. 1, the center robot CR has a U-shaped hand H in plan view, similar to the indexer robot IR. Here, the central robot CR has two hands H. The two hands H are placed at different heights. Each hand H can support the substrate 9 in a horizontal position. The central robot CR can move each hand H in the horizontal and vertical directions. Furthermore, the central robot CR can change the direction of the hand H by rotating (rotating) about an axis along the vertical direction. The center robot CR is surrounded by a plurality of processing units 110 when viewed from above. The central robot CR can have the hand H facing any one of the processing units 110 and the substrate platform PASS. Here, for example, by moving the hand H, the central robot CR can perform a carry-in operation of carrying the substrate 9 into each processing unit 110 and a carry-out operation of carrying the substrate 9 out of each processing unit 110. Further, for example, by moving the hand H, the central robot CR can carry out a carry-in operation of carrying the substrate 9 into the substrate platform PASS, and a carrying-out operation of carrying out the substrate 9 from the substrate platform PASS. .

The unprocessed substrate 9 is taken out from the carrier C by the indexer robot IR and delivered to the center robot CR via the substrate platform PASS. The central robot CR carries this unprocessed substrate 9 into the processing unit 110. The processing unit 110 processes the substrate 9 . The processed substrate 9 is taken out from the processing unit 110 by the center robot CR, passes through other processing units 110 as necessary, and is delivered to the indexer robot IR via the substrate platform PASS. The indexer robot IR carries the processed substrate 9 into the carrier C. Through the above steps, the substrate 9 is processed.

<First embodiment>
<Substrate processing equipment>
FIG. 2 is a diagram schematically showing an example of the configuration of the substrate processing apparatus 1, which corresponds to one of the processing units 110. The substrate processing apparatus 1 is a single-wafer type apparatus that processes substrates 9 one by one. The substrate 9 is, for example, a silicon substrate and has a disk shape. The substrate processing apparatus 1 holds a substrate 9, sequentially supplies various processing liquids to the substrate 9, and performs processing on the substrate 9 according to the processing liquid.

The substrate processing apparatus 1 includes a substrate holding section 2, a substrate rotation mechanism 3, a processing liquid supply section 4, and a resistance value changing mechanism 5. The substrate holder 2, the substrate rotation mechanism 3, and the resistance value changing mechanism 5 are housed in a box-shaped chamber. The chamber defines a substantially sealed interior space.

The substrate holder 2 holds the substrate 9 in a horizontal position. The horizontal position here is a position in which the thickness direction of the substrate 9 is along the vertical direction. Hereinafter, of both main surfaces of the substrate 9, the main surface facing upward while being held by the substrate holder 2 will also be referred to as the upper surface, and the main surface facing downward will also be referred to as the lower surface.

The substrate rotation mechanism 3 rotates the substrate holder 2 around the rotation axis J1. The rotation axis J1 is an axis that passes through the center of the substrate 9 held by the substrate holder 2 and extends in the vertical direction. When the substrate rotation mechanism 3 rotates the substrate holder 2, the substrate 9 held by the substrate holder 2 also rotates around the rotation axis J1.

The processing liquid supply section 4 supplies a processing liquid to the main surface of the rotating substrate 9. For example, the processing liquid supply unit 4 supplies the processing liquid toward the center of the substrate 9 . The processing liquid that has landed on the center of the substrate 9 is subjected to centrifugal force due to the rotation of the substrate 9, spreads over the entire main surface of the substrate 9, and scatters outward from the periphery of the substrate 9. Thereby, the processing liquid acts on the main surface of the substrate 9, and processing based on the type of processing liquid can be performed on the substrate 9. For example, when the processing liquid is a static eliminating liquid, the substrate 9 can be neutralized, and when the processing liquid is an etching liquid, the main surface of the substrate 9 can be etched.

The resistance value changing mechanism 5 is a mechanism that changes the electrical resistance value between the substrate holder 2 and a grounding member (not shown). When the resistance value is low, the electric charge generated on the substrate 9 easily flows to the ground member via the substrate holding part 2. On the other hand, when the resistance value is high, the electric charge generated in the substrate 9 is difficult to flow to the grounding member.

<Substrate holding part 2>
The substrate holder 2 includes a plurality of chuck pins 22. The plurality of chuck pins 22 are arranged along the periphery of the substrate 9 in plan view, and are arranged, for example, at equal intervals. Each chuck pin 22 moves between a holding position where it contacts the periphery of the substrate 9 and a release position where it is away from the periphery of the substrate 9. The plurality of chuck pins 22 hold the peripheral edge of the substrate 9 in a horizontal position by stopping at respective holding positions. The plurality of chuck pins 22 release the holding of the substrate 9 by moving from the respective holding positions to the release positions.

In the example of FIG. 2, the substrate holding section 2 includes a facing plate section 21. As shown in FIG. The opposing plate portion 21 has, for example, a disk shape centered on the rotation axis J1. The substrate holding section 2 holds the substrate 9 above the opposing plate section 21 , and the surface facing upward of the opposing plate section 21 is an opposing surface 211 that faces the lower surface of the substrate 9 . The opposing surface 211 extends in a direction perpendicular to the rotation axis J1. The outer peripheral edge of the opposing surface 211 is located outside the substrate 9. In other words, the diameter of the opposing surface 211 is larger than the diameter of the substrate 9.

The plurality of chuck pins 22 are arranged side by side along the periphery of the substrate 9. Specifically, the plurality of chuck pins 22 are arranged at approximately equal intervals along a reference circle having a slightly larger diameter than the substrate 9 . For example, six chuck pins 22 are arranged at 60 degree intervals.

A plurality of holes 213 are provided in the opposing surface 211 . The cross-sectional shape of the hole 213 perpendicular to the vertical direction is circular. As a specific example, six holes 213 are arranged at 60 degree intervals. The plurality of chuck pins 22 are inserted into the plurality of holes 213, respectively. A bearing 214 is provided in the hole 213, and the chuck pin 22 is rotatably supported by the bearing 214 with respect to the opposing plate 21 about a rotation axis J2 of the hole 213. In the following description, the rotation axis J2 will be referred to as a "chuck rotation axis J2." In one example of the substrate holding section 2, a locking member (not shown) provided in the hole 213 allows the chuck pin 22 to rotate within a predetermined angular range (an angular range including a holding position and a release position, which will be described later). ) is limited to.

Each chuck pin 22 includes a protrusion 221 and a support 222. The support body 222 is connected to the bearing 214 inside the hole 213. Specifically, the support body 222 is fixed to the inner ring of the bearing 214, and the outer ring of the bearing 214 is fixed to the opposing plate part 21 inside the hole part 213. The protrusion 221 is provided on the upper surface of the support 222 and protrudes upward. The protrusion 221 is arranged at a position offset from the chuck rotation axis J2 in plan view. Therefore, as the chuck pin 22 rotates around the chuck rotation axis J2, the protrusion 221 moves along the circumferential direction around the chuck rotation axis J2. As the chuck pin 22 rotates, the protrusion 221 reciprocates between a holding position in which it contacts the periphery of the substrate 9 and a release position away from the periphery of the substrate 9 .

The protrusion 221 has a chuck contact surface, and the chuck contact surface contacts the peripheral edge of the substrate 9 . The chuck contact surface has a V-shape, for example, and can grip the substrate 9 by sandwiching it in its thickness direction.

The substrate holding section 2 is provided with a chuck driving section 23 . The chuck drive unit 23 drives the chuck pin 22 to rotate the chuck pin 22 between a holding position and a release position. In other words, the chuck drive unit 23 applies a driving force to the chuck pin 22 to rotate the chuck pin 22 . The chuck drive unit 23 may include, for example, a motor.

Alternatively, the chuck drive unit 23 includes a first magnet connected to the lower end of the support body 222 of the chuck pin 22, a second magnet, and a movement mechanism that changes the distance between the first magnet and the second magnet. It's okay to stay. The moving mechanism includes, for example, a ball screw mechanism or an air cylinder, and moves the second magnet along the vertical direction. When the moving mechanism brings the second magnet closer to the first magnet, the chuck pin 22 can be rotated to one of the holding position and the release position due to the magnetic action between the first magnet and the second magnet. Conversely, when the moving mechanism moves the second magnet away from the first magnet, the magnetic action between the first magnet and the second magnet disappears, and the chuck pin 22 can be rotated to the other of the holding position and the release position. can.

<Substrate rotation mechanism>
The substrate rotation mechanism 3 rotates the substrate holder 2 around the rotation axis J1. In the example of FIG. 2, the substrate rotation mechanism 3 includes a shaft portion 31 and a motor 32. The shaft portion 31 has a cylindrical shape centered on the rotation axis J1, and its upper end is fixed to the center of the lower surface of the substrate holding portion 2 (specifically, the lower surface 212 of the opposing plate portion 21). be done. The shaft portion 31 is rotatably connected to a motor 32. The motor 32 rotates the shaft portion 31 to rotate the substrate holding portion 2 around the rotation axis J1. As a result, the substrate 9 held by the substrate holder 2 also rotates around the rotation axis J1.

In the example of FIG. 2, the motor 32 is fixed to the floor member 10 of the chamber via a fixing member 33. The fixing member 33 extends vertically upward from the floor member 10 of the chamber. In the example of FIG. 2, the fixing member 33 is fixed to the motor case of the motor 32 and supports the motor 32 in a state separated from the floor member 10.

<Processing liquid supply section>
The processing liquid supply unit 4 supplies a processing liquid (including a chemical solution and a rinsing liquid) to the main surface of the substrate 9 held by the substrate holding unit 2 . The processing liquid supply section 4 includes a chemical solution supply section 41 . The chemical supply unit 41 supplies a chemical to the main surface of the substrate 9 held by the substrate holding unit 2 . As the chemical solution, for example, a chemical solution containing hydrofluoric acid or a mixed solution of sulfuric acid and hydrogen peroxide (SPM) can be used. As the chemical solution containing hydrofluoric acid, for example, dilute hydrofluoric acid (DHF) can be used.

The chemical liquid supply unit 41 includes a chemical liquid nozzle 411 , a supply pipe 412 , a valve 413 , and a chemical liquid supply source 415 . The chemical liquid nozzle 411 is supported by a nozzle arm 414 within the chamber. The nozzle arm 414 is connected to a nozzle moving mechanism (not shown). The nozzle moving mechanism moves the chemical liquid nozzle 411 between the discharge position and the standby position. The discharge position is, for example, a position that faces the center of the upper surface of the substrate 9 in the vertical direction, and the standby position is, for example, a position that does not face the substrate 9 in the vertical direction. The chemical liquid nozzle 411 is connected to a chemical liquid supply source 415 via a supply pipe 412. By supplying the chemical liquid from the chemical liquid supply source 415 to the chemical liquid nozzle 411 via the supply pipe 412, the chemical liquid is discharged from the chemical liquid nozzle 411 toward the center of the upper surface of the substrate 9.

The chemical liquid supply unit 41 supplies a chemical liquid to the upper surface of the rotating substrate 9. As a result, the chemical liquid that has landed on the upper surface of the substrate 9 flows toward the periphery of the substrate 9 under the influence of centrifugal force caused by the rotation of the substrate 9, and is scattered outward from the periphery of the substrate 9. By acting on the upper surface of the substrate 9 with the chemical liquid, the substrate 9 can be subjected to processing depending on the type of chemical liquid.

The processing liquid supply section 4 also includes a rinsing liquid supply section 42 . The rinsing liquid supply section 42 supplies a rinsing liquid to the main surface of the substrate 9 held by the substrate holding section 2 . For example, pure water (DIW) can be used as the rinsing liquid.

The rinse liquid supply section 42 includes a rinse nozzle 421, a supply pipe 422, a valve 423, and a rinse liquid supply source 425. Rinse nozzle 421 is supported within the chamber by nozzle arm 424 . The nozzle arm 424 is connected to a nozzle moving mechanism (not shown). The nozzle moving mechanism moves the rinse nozzle 421 between the discharge position and the standby position. The discharge position is, for example, a position that faces the center of the upper surface of the substrate 9 in the vertical direction, and the standby position is, for example, a position that does not face the substrate 9 in the vertical direction. The rinse nozzle 421 is connected to a rinse liquid supply source 425 via a supply pipe 422 . By supplying the rinsing liquid from the rinsing liquid supply source 425 to the rinsing nozzle 421 via the supply pipe 422, the rinsing liquid is discharged from the rinsing nozzle 421 toward the center of the upper surface of the substrate 9.

In the above example, the chemical solution nozzle 411 and the rinse nozzle 421 are connected to different nozzle arms 414 and 424, respectively, and move independently of each other, but this is not necessarily the case. For example, the chemical solution nozzle 411 and the rinse nozzle 421 may be connected to the same nozzle arm and move together. Furthermore, a single nozzle may be used as the chemical liquid nozzle 411 and the rinse nozzle 421.

The rinsing liquid supply section 42 supplies a rinsing liquid to the upper surface of the rotating substrate 9. As a result, the rinsing liquid that has landed on the upper surface of the substrate 9 flows toward the periphery of the substrate 9 due to the centrifugal force caused by the rotation of the substrate 9, and is scattered outward from the periphery of the substrate 9. The rinsing liquid can wash away the chemical solution on the upper surface of the substrate 9.

<Cup part>
In the example of FIG. 2, a cup portion 7 is provided. The cup portion 7 has a cylindrical shape and surrounds the substrate holding portion 2 . The upper end of the cup portion 7 is located above the upper surface of the substrate 9 held by the substrate holding portion 2. The processing liquid supplied to the upper surface of the rotating substrate 9 and scattered from the periphery of the substrate 9 comes into contact with the inner circumferential surface of the cup portion 7 and is recovered by a recovery mechanism (not shown).

<Resistance value changing mechanism>
The resistance value changing mechanism 5 changes the resistance value of the conduction path R1 between the substrate 9 and the grounding member while the substrate 9 is held by the substrate holder 2. Below, an example of the conduction path R1 will be described first. The conduction path R1 is, for example, from the chuck pin 22 that holds the substrate 9, through the bearing 214, the opposing plate part 21, the shaft part 31, the motor 32, the fixing member 33, and the chamber floor member 10 in this order to the ground member (non-conductor). (as shown). A ground potential is applied to the ground member.

The bearing 214, the opposing plate portion 21, the shaft portion 31, the fixing member 33, and the floor member 10 are electrically conductive and are each made of, for example, metal. For example, the inner ring and outer ring of the bearing 214 and the rolling elements between them are formed of metal. The shaft portion 31 is made of metal, for example, and is connected to the motor 32 via a bearing (not shown). The bearing is also electrically conductive and is made of metal, for example. The bearing is connected to the stator of the motor 32 (including the motor case). The stator is also conductive and is made of metal, for example. The fixing member 33 is connected to the stator of the motor 32 and also to the floor member 10 of the chamber. The fixing member 33 and the floor member 10 are also made of metal, for example. The chamber floor member 10 is electrically connected to a ground member.

Note that the various members constituting the conduction path R1 do not necessarily need to be composed only of conductive members. Various members may include an insulating member as long as the conduction path R1 is not obstructed. For example, a portion of the various members other than the portion that constitutes the conduction path R1 may be made of an insulating member.

For example, the resistance value of the conduction path R1 can be changed as follows. For example, the chuck pins 22 include a first chuck pin group made of a high-resistance material with a high specific resistance value, and a second chuck pin group made of a low-resistance material with a lower specific resistance value than the first chuck pin group. The chuck pins 22 holding the substrate 9 are switched between the first chuck pin group and the second chuck pin group. Thereby, the resistance value of the conduction path R1 can be changed.

3 and 4 are plan views schematically showing an example of the configuration of the substrate holding section 2. FIG. In the examples of FIGS. 3 and 4, the shape of the chuck pin 22 is shown in a simplified manner for the sake of simplicity. In the examples of FIGS. 3 and 4, six chuck pins 22 are shown, and these are classified into three chuck pins 22a and three chuck pins 22b.

The three chuck pins 22a are arranged at equal intervals along the periphery of the substrate 9, specifically, at intervals of 120 degrees. The three chuck pins 22b are also arranged at equal intervals along the periphery of the substrate 9, specifically, at intervals of 120 degrees. The chuck pins 22a, 22b are arranged on one virtual circle centered on the rotation axis J1. Note that the number of chuck pins 22a constituting the first chuck pin group and the number of chuck pins 22b constituting the second chuck pin group can be changed as appropriate. The numbers of chuck pins 22a and chuck pins 22b may be different from each other.

All of the chuck pins 22 do not need to be made of the same material, and the chuck pins 22 may be made of a combination of a plurality of members made of different materials. In short, it is sufficient that the resistance value of the path from the chuck contact surface to the bearing 214 is high in the chuck pin 22a and low in the chuck pin 22b.

Furthermore, the chuck pins 22a and 22b may be made of a composite material. The composite material is, for example, a material containing a conductive material and a synthetic resin. The conductive material is dispersed within the synthetic resin, and the composite material has electrical conductivity that depends on the amount of the conductive material. By adjusting the proportion of the conductive material contained in this composite material, the specific resistance value of the composite material can be adjusted. Specifically, the chuck pin 22a is made of a composite material (high resistance material) with a high proportion of conductive material, and the chuck pin 22b is made of a composite material (low resistance material) with a low proportion of conductive material. .

The conductive material includes, for example, at least one of carbon fiber, carbon powder, and particles. Nanocarbon materials such as carbon nanotubes, fullerene, and graphene may be employed as the conductive material. The synthetic resin includes, for example, at least one of PFA (tetrafluoro ethylene-perfluoro alkylvinyl ether copolymer), PCTFE (poly chlorotrifuruoro ethylene), PTFE (polytetrafluoroethylene), and PEEK (polyetheretherketone).

The chuck drive unit 23 drives the first chuck pin group and the second chuck pin group independently of each other. The chuck drive unit 23 switches the chuck pins 22 that hold the substrate 9 between the first chuck pin group and the second chuck pin group. In FIGS. 3 and 4, the protrusion 221 is shown as a rectangle. In FIGS. 3 and 4, the protrusion 221 having a long axis parallel to the radial direction centered on the rotation axis J1 indicates that the chuck pin 22 is stopped at the holding position, and the protrusion 221 has a long axis parallel to the rotation axis J1. The protruding portion 221 having a long axis parallel to the circumferential direction around the center indicates that the chuck pin 22 is stopped at the release position.

The chuck driving unit 23 causes the plurality of chuck pins 22a to hold the peripheral edge of the substrate 9 by moving the chuck pins 22a to their respective holding positions and moving the chuck pins 22b to their respective release positions (FIG. 3). As a result, the chuck pins 22a made of a high-resistance material hold the substrate 9. Therefore, the resistance value of the conduction path R1 can be increased.

On the other hand, the chuck driving unit 23 causes the plurality of chuck pins 22b to hold the periphery of the substrate 9 by moving the chuck pins 22a to their respective release positions and moving the chuck pins 22b to their respective holding positions (see FIG. 4). Thereby, the chuck pin 22b made of a low resistance material holds the substrate 9. Therefore, the resistance value of the conduction path R1 can be lowered.

According to such a configuration, the resistance value changing mechanism 5 is configured by the substrate holding section 2 including the first chuck pin group, the second chuck pin group, and the chuck driving section 23.

<Control unit>
The control unit 6 can, for example, control the operation of each unit included in the substrate processing system 100. FIG. 5 is a diagram schematically showing an example of the electrical configuration of the substrate processing system 100. The control unit 6 is an electronic circuit, and may include, for example, a data processing device 61 and a storage medium 62. In the example of FIG. 5, the data processing device 61 and the storage medium 62 are interconnected via a bus 63. The data processing device 61 may be, for example, an arithmetic processing device such as a CPU (Central Processor Unit). The storage medium 62 may include a non-temporary storage medium (for example, a ROM (Read Only Memory) or a hard disk) 621 and a temporary storage medium (for example, a RAM (Random Access Memory)) 622. The non-temporary storage medium 621 may store, for example, a program that defines the processing that the control unit 6 executes. When the data processing device 61 executes this program, the control unit 6 can execute the processing specified in the program. Of course, part or all of the processing executed by the control unit 6 may be executed by hardware.

In FIG. 5, an example is schematically shown in which the indexer robot IR, center robot CR, substrate holding section 2, substrate rotation mechanism 3, processing liquid supply section 4, and resistance value changing mechanism 5 are connected to the bus 63. There is.

<Process flow of substrate processing equipment>
FIG. 6 is a flowchart showing an example of the flow of substrate processing. Here, it is assumed that an oxide film, which is an example of a film to be etched, is formed on the upper surface of the substrate 9. During substrate processing, dilute hydrofluoric acid, which is an example of a chemical solution, is supplied to the upper surface of the substrate 9 to remove the oxide film. Remove by etching. The oxide film may be exposed on a part of the upper surface of the substrate 9, or may be exposed on the entire upper surface of the substrate 9.

First, the central robot CR carries an unprocessed substrate 9 into the substrate processing apparatus 1, and the substrate holding section 2 holds the substrate 9 in a horizontal position (step S1: holding step).

FIG. 7 is a graph showing an example of the resistance value of the conduction path R1 according to each process. In the example of FIG. 7, the substrate holder 2 holds the substrate 9 in a state where the resistance value of the conduction path R1 is high. As a specific example, the chuck drive unit 23 moves the first chuck pin group to the holding position and moves the second chuck pin group to the release position. Thereby, the substrate 9 is held by the plurality of chuck pins 22a. Since the plurality of chuck pins 22a are made of a high resistance material, the resistance value of the conduction path R1 is high.

Next, the substrate rotation mechanism 3 rotates the substrate 9 (step S2: rotation step). Specifically, the motor 32 rotates the shaft section 31 and the substrate holding section 2 . As a result, the substrate 9 held by the substrate holder 2 rotates around the rotation axis J1.

Next, the chemical liquid supply unit 41 supplies a chemical liquid (dilute hydrofluoric acid) to the upper surface of the rotating substrate 9 (step S3: chemical liquid process). Specifically, the nozzle moving mechanism moves the chemical liquid nozzle 411 to the discharge position, and the valve 413 opens the internal flow path of the supply pipe 412. As a result, the chemical liquid from the chemical liquid supply source 415 flows through the internal flow path of the supply pipe 412 toward the chemical liquid nozzle 411, and is discharged from the discharge port of the chemical liquid nozzle 411 toward the center of the upper surface of the substrate 9.

The chemical liquid that has landed on the center of the substrate 9 is subjected to centrifugal force as the substrate 9 rotates, spreads over the entire upper surface of the substrate 9, and scatters outward from the periphery of the substrate 9. As a result, the chemical solution acts on the film to be etched on the upper surface of the substrate 9, thereby etching the film to be etched.

For example, when the chemical liquid processing time has elapsed from the start of the chemical liquid supply, the valve 413 closes the internal flow path of the supply pipe 412. As a result, the discharge of the chemical liquid from the chemical liquid nozzle 411 is stopped. The chemical processing time is a time for completing the processing on the substrate 9, and is set in advance, for example. The nozzle moving mechanism moves the chemical liquid nozzle 411 to the standby position.

Next, the resistance value changing mechanism 5 reduces the resistance value of the conduction path R1 (step S4: resistance value changing step). Specifically, the chuck drive unit 23 switches the chuck pins 22 that hold the substrate 9 from the first chuck pin group to the second chuck pin group. For example, the chuck drive unit 23 moves the second chuck pin group to the holding position, and then moves the first chuck pin group to the release position. Thereby, the plurality of chuck pins 22b hold the peripheral edge of the substrate 9. Since the chuck pin 22b is made of a low resistance material, the resistance value of the conduction path R1 is reduced (see also FIG. 7).

Next, the rinsing liquid supply unit 42 supplies the rinsing liquid to the upper surface of the rotating substrate 9 (step S5: rinsing process). Specifically, the nozzle moving mechanism moves the rinse nozzle 421 to the discharge position, and the valve 423 opens the internal flow path of the supply pipe 422. As a result, the rinsing liquid (for example, pure water) from the rinsing liquid supply source 425 flows through the internal flow path of the supply pipe 422 toward the rinsing nozzle 421, and from the discharge port of the rinsing nozzle 421 toward the center of the upper surface of the substrate 9. is discharged.

The rinsing liquid that has landed on the center of the substrate 9 is subjected to centrifugal force caused by the rotation of the substrate 9, spreads over the entire upper surface of the substrate 9, and scatters outward from the periphery of the substrate 9. As a result, the chemical solution remaining on the upper surface of the substrate 9 is washed away by the rinsing liquid. In other words, the chemical liquid on the upper surface of the substrate 9 is replaced with the rinsing liquid.

For example, when the rinsing processing time has elapsed from the start of supply of the rinsing liquid, the valve 423 closes the internal flow path of the supply pipe 422. As a result, the discharge of the rinse liquid from the rinse nozzle 421 is stopped. The rinsing processing time is a time sufficient to complete the replacement of the chemical solution with the rinsing liquid, and is set in advance, for example. The nozzle moving mechanism moves the rinse nozzle 421 to the standby position.

Next, the substrate 9 is dried (step S6: drying process). For example, the substrate rotation mechanism 3 increases the rotation speed of the substrate 9 (so-called spin drying). This dries the substrate 9. When the substrate 9 is sufficiently dried, the substrate rotation mechanism 3 stops rotating the substrate 9.

Next, the center robot CR carries out the processed substrate 9 from the substrate processing apparatus 1 (step S7).

In the manner described above, processing (etching processing in the above example) can be performed on the substrate 9.

Furthermore, in the above example, in the chemical liquid step (step S3), dilute hydrofluoric acid is supplied to the upper surface of the substrate 9 while the resistance value of the conduction path R1 is high. For comparison, a case will be described in which dilute hydrofluoric acid is supplied to the upper surface of the substrate 9 while the resistance value of the conduction path R1 is low. In this case, the etching rate is higher in the first region of the upper surface of the substrate 9 near the chuck pin 22 than in the region away from the chuck pin 22 (for example, the central region). As a result, the oxide film is etched to a greater extent in the first region of the upper surface of the substrate 9 than in the second region, resulting in greater in-plane variation in etching.

On the other hand, in the above example, dilute hydrofluoric acid is supplied to the upper surface of the substrate 9 while the resistance value of the conduction path R1 is high. Therefore, in-plane variations in etching caused by the low resistance value of the conduction path R1 can be reduced.

On the other hand, in the rinsing step (step S5), the rinsing liquid is supplied to the upper surface of the substrate 9 while the resistance value of the conduction path R1 is small. The specific resistance value of this rinsing liquid is higher than that of the chemical solution (diluted hydrofluoric acid). Therefore, charges are likely to be generated on the substrate 9 due to friction between the rinsing liquid and the substrate 9. In other words, the substrate 9 is easily charged. If the substrate 9 is charged, problems may occur in subsequent steps (for example, a drying step, a carrying out step, or a step after the substrate processing apparatus 1). However, in the rinsing process, the resistance value of the conduction path R1 is small. Therefore, the electric charge generated on the substrate 9 easily flows from the chuck pin 22b to the grounding member via the conduction path R1. Therefore, charging generated on the substrate 9 during the rinsing process can be reduced or avoided. As a result, the occurrence of defects in subsequent steps can be reduced or avoided.

<Type of chemical solution>
In the above example, the case where the oxide film of the substrate 9 was etched was described. However, this embodiment is not necessarily limited to etching processing. For example, when silicon is exposed on the main surface of the substrate 9, when a mixed solution of sulfuric acid and hydrogen peroxide (SPM) is supplied to the main surface of the substrate 9, the chemical It is possible to form a target oxide film.

In this case, when the resistance value of the conduction path R1 is high, the oxide film is formed at a higher rate in the first region of the upper surface of the substrate 9 near the chuck pin 22 than in the second region. As a result, the thickness of the oxide film in the first region of the upper surface of the substrate 9 becomes larger than that in the second region. In other words, the in-plane variation in the thickness of the oxide film increases.

Therefore, when SPM is employed as the chemical liquid to be supplied in the chemical liquid process, it is preferable to perform the same process as in FIG. 6 . However, silicon, for example, is exposed on the upper surface of the substrate 9. Further, in the chemical liquid process (step S3), the chemical liquid supply unit 41 supplies SPM as a chemical liquid to the upper surface of the substrate 9. Thereby, a chemical oxide film (silicon oxide film) can be formed on the upper surface of the substrate 9. Note that it is preferable that the chemical liquid supply unit 41 generates SPM by mixing sulfuric acid and hydrogen peroxide in or immediately before the chemical liquid nozzle 411, and discharges the SPM from the discharge port of the chemical liquid nozzle 411. This is because the activation power of SPM can only be ensured for a short time after SPM generation.

Also in this substrate processing, SPM is supplied to the upper surface of the substrate 9 in the chemical liquid step (step S3) while the resistance value of the conduction path R1 is high. Therefore, in-plane variations in the thickness of the oxide film caused by the low resistance value of the conduction path R1 can be reduced.

Note that the chemical liquid is not limited to a chemical liquid containing hydrofluoric acid and SPM. In short, the substrate processing method of this embodiment can be applied to any chemical solution that causes in-plane variations in processing due to the small resistance value of the conduction path R1 between the substrate 9 and the grounding member. Other examples of chemical solutions include ozone water and the like. In the following, a case will be described in which dilute hydrofluoric acid is typically used as the chemical solution.

<Other examples of resistance value changing mechanism>
FIG. 8 is a diagram schematically showing an example of the configuration of the substrate processing apparatus 1A. The substrate processing apparatus 1A has the same configuration as the substrate processing apparatus 1 except for the configuration of the resistance value changing mechanism 5.

The resistance value changing mechanism 5 includes a variable resistor 51. This variable resistor 51 is provided on the conduction path R1. For example, the variable resistor 51 may be connected in series with other members forming the conduction path R1. As a more specific example, the variable resistor 51 may be provided between the motor case of the motor 32 and the fixed member 33. The resistance value of the variable resistor 51 is controlled by the control section 6. By changing the resistance value of the variable resistor 51 by the control unit 6, the resistance value of the conduction path R1 can be changed.

In the substrate processing apparatus 1A, since the resistance value of the conduction path R1 can be changed by the variable resistor 51, the resistance values of all the chuck pins 22 may be substantially the same. In this case, the chuck drive unit 23 may drive all the chuck pins 22 in one piece.

The flow of substrate processing in the substrate processing apparatus 1A is similar to that shown in FIG. However, it is not necessary to switch the chuck pins 22 that hold the substrate 9 in order to change the resistance value of the conduction path R1, and the resistance value of the conduction path R1 may be changed only by the variable resistor 51. Alternatively, in addition to changing the variable resistor 51, the chuck pins 22a and 22b may be switched. An example in which the resistance value of the conduction path R1 is changed by the variable resistor 51 will be described below. The control unit 6 sets the resistance value of the variable resistor 51 to a high resistance value immediately before the chemical liquid process, for example, so that the resistance value of the conduction path R1 becomes high in the chemical liquid process (step S3). Thereby, the chemical liquid process can be performed in a state where the resistance value of the conduction path R1 is high. Furthermore, in the resistance value changing step (step S4), the control unit 6 reduces the resistance value of the variable resistor 51 from a high resistance value to a low resistance value. Thereby, the rinsing process (step S5) can be performed in a state where the resistance value of the conduction path R1 is low.

This also makes it possible to reduce in-plane variations in etching and also to reduce charging of the substrate 9 due to the rinsing process. Further, by using the variable resistor 51, the resistance value of the conduction path R1 can be adjusted more finely. On the other hand, by using the chuck pins 22a and 22b having different resistance values, the resistance value of the conduction path R1 can be changed with a simple configuration.

In addition, below, the case where the board holding part 2 containing the 1st chuck pin group and the 2nd chuck pin group is typically employ|adopted as the resistance value changing mechanism 5 will be described.

<Second embodiment>
When a processing liquid with a low specific resistance value is supplied to the charged substrate 9, a large current flows from the substrate 9 to the processing liquid, which may cause damage to the substrate 9. Therefore, in the second embodiment, a technique that can eliminate static electricity from the substrate 9 will be described.

FIG. 9 is a diagram schematically showing an example of the configuration of the substrate processing apparatus 1B. The substrate processing apparatus 1B has the same structure as the substrate processing apparatus 1 except for the structure of the processing liquid supply section 4. In the second embodiment, the processing liquid supply section 4 further includes a static eliminating liquid supply section 43. The static eliminating liquid supply unit 43 can supply static eliminating liquid to the main surface of the substrate 9 . By supplying the static eliminating liquid to the main surface of the rotating substrate 9, the static eliminating liquid can eliminate static electricity from the substrate 9. As the static eliminating liquid, for example, pure water or carbon water (CO ₂ water) can be used.

The static eliminating liquid supply section 43 includes a static eliminating nozzle 431, a supply pipe 432, a valve 433, and a static eliminating liquid supply source 435. The static elimination nozzle 431 is supported by a nozzle arm 434 within the chamber. The nozzle arm 434 is connected to a nozzle moving mechanism (not shown). The nozzle moving mechanism moves the static elimination nozzle 431 between the discharge position and the standby position. The discharge position is, for example, a position that faces the center of the upper surface of the substrate 9 in the vertical direction, and the standby position is, for example, a position that does not face the substrate 9 in the vertical direction. The static eliminating nozzle 431 is connected to a static eliminating liquid supply source 435 via a supply pipe 432. By supplying the static eliminating liquid from the static eliminating liquid supply source 435 to the static eliminating nozzle 431 via the supply pipe 432, the static eliminating liquid is discharged from the static eliminating nozzle 431 toward the center of the upper surface of the substrate 9.

Note that the static elimination nozzle 431 may be connected to a nozzle arm that is connected to at least one of the chemical liquid nozzle 411 and the rinse nozzle 421, and may move together with at least one of them. Furthermore, the static elimination nozzle 431 may also be used as at least one of the chemical solution nozzle 411 and the rinse nozzle 421.

Furthermore, when pure water is used as both the rinsing liquid and the static eliminating liquid, the static eliminating liquid supply section 43 is also used as the rinsing liquid supply section 42 . In this case, the static eliminating nozzle 431, the supply pipe 432, the valve 433, and the static eliminating liquid supply source 435 are not provided, and the rinse nozzle 421 functions as a static eliminating nozzle.

<Substrate processing flow>
FIG. 10 is a flowchart showing an example of the flow of substrate processing. First, the central robot CR carries the substrate 9 into the substrate processing apparatus 1, and the substrate holding section 2 holds the substrate 9 (step S11: holding process). Note that here, the substrate 9 is electrically charged in a previous process before being carried into the substrate processing apparatus 1. For example, in the pre-process, a dry process such as dry etching (for example, ion etching) is performed on the substrate 9. When dry etching is performed on the substrate 9, the substrate 9 becomes highly charged. The surface potential of the substrate 9 can be used as an index indicating the amount of charge on the substrate 9. The surface potential of the substrate 9 here is, for example, a potential based on the ground potential of the grounding member. The larger the absolute value of the surface potential, the larger the amount of charge.

FIG. 11 is a graph showing an example of the resistance value of the conduction path R1 according to each process. In step S1, the substrate holding section 2 holds the substrate 9 in a state where the resistance value of the conduction path R1 becomes high. As a specific example, the chuck drive unit 23 moves a first chuck pin group made of a high-resistance material to a holding position, and moves a second chuck pin group to a release position. Thereby, the resistance value of the conduction path R1 can be increased. According to this, even if the substrate 9 is charged, the current flowing from the substrate 9 to the chuck pins 22b can be reduced, and damage to the substrate 9 can be reduced or avoided.

Next, the substrate rotation mechanism 3 rotates the substrate 9 (step S12: rotation step). Specifically, the motor 32 rotates the shaft portion 31 and the substrate holding portion 2 around the rotation axis J1. As a result, the substrate 9 held by the substrate holder 2 rotates around the rotation axis J1.

Next, the static eliminating liquid supply unit 43 supplies static eliminating liquid to the upper surface of the rotating substrate 9 (step S13: static eliminating process). Specifically, the nozzle moving mechanism moves the static elimination nozzle 431 to the discharge position, and the valve 433 opens the internal flow path of the supply pipe 432. As a result, the static eliminating liquid from the static eliminating liquid supply source 435 flows through the internal flow path of the supply pipe 432 toward the static eliminating nozzle 431, and is discharged from the discharge port of the static eliminating nozzle 431 toward the center of the upper surface of the substrate 9.

The static eliminating liquid that has landed on the center of the substrate 9 is subjected to centrifugal force as the substrate 9 rotates, spreads over the entire upper surface of the substrate 9, and scatters outward from the periphery of the substrate 9. The specific resistance value of this static eliminating liquid is larger than the specific resistance value of the chemical solution. The static eliminating liquid is, for example, pure water, and its specific resistance value is, for example, several MΩ·cm or more. Therefore, even if the static eliminating liquid begins to be discharged from the discharge port of the static eliminating nozzle 431 and the liquid column-shaped tip of the static eliminating liquid descends and approaches the charged substrate 9, the tip of the static eliminating liquid does not reach the charged substrate 9. A large current (discharge) is unlikely to occur between the substrate 9 and the substrate 9.

Further, since the specific resistance value of the static eliminating liquid is relatively high, the static eliminating liquid gradually eliminates static electricity from the substrate 9 over time. In other words, the amount of charge (current) transferred from the substrate 9 to the static eliminator per unit time is not so large, and the static electricity is removed from the substrate 9 over a relatively long period of time. Therefore, damage to the substrate 9 caused by a large current flowing from the substrate 9 to the static eliminator can be reduced or avoided.

Further, in the static elimination process (step S13), the substrate 9 is held by the first chuck pin group, and the resistance value of the conduction path R1 is high (see also FIG. 11). Therefore, the charges on the substrate 9 are less likely to flow to the grounding member via the conduction path R1. Therefore, damage to the substrate 9 caused by a large current flowing from the substrate 9 to the first chuck pin group can also be reduced or avoided.

For example, when the static elimination processing time has elapsed from the start of supply of the static eliminating liquid, the valve 433 closes the internal flow path of the supply pipe 432. The static elimination processing time is the time required to sufficiently eliminate static from the substrate 9, and is set, for example, in advance. As a result, discharge of the static eliminating liquid from the static eliminating nozzle 431 is stopped. The nozzle moving mechanism moves the static elimination nozzle 431 to the standby position.

Next, the chemical liquid supply unit 41 supplies a chemical liquid (dilute hydrofluoric acid) to the upper surface of the rotating substrate 9 (step S14: chemical liquid process). As a result, the chemical solution acts on the film to be etched on the upper surface of the substrate 9, thereby etching the film to be etched. Even in this chemical process, since the resistance value of the conduction path R1 is high (see also FIG. 11), in-plane variations in etching can be reduced.

For example, when the chemical liquid processing time has elapsed from the start of the chemical liquid supply, the valve 413 closes the internal flow path of the supply pipe 412. As a result, the discharge of the chemical liquid from the chemical liquid nozzle 411 is stopped.

Next, the resistance value changing mechanism 5 reduces the resistance value of the conduction path R1 (step S15: resistance value changing step). Specifically, the chuck drive unit 23 switches the chuck pins 22 that hold the substrate 9 from the first chuck pin group to the second chuck pin group. This reduces the resistance value of the conduction path R1.

Next, the rinsing liquid supply unit 42 supplies the rinsing liquid to the upper surface of the rotating substrate 9 (step S16: rinsing process). As a result, the chemical liquid on the upper surface of the substrate 9 is replaced with the rinsing liquid. In this rinsing step, since the resistance value of the conduction path R1 is low (see also FIG. 11), charging of the substrate 9 caused by friction between the rinsing liquid and the substrate 9, etc. can be reduced.

For example, when the rinsing processing time has elapsed from the start of supply of the rinsing liquid, the valve 423 closes the internal flow path of the supply pipe 422. As a result, the discharge of the rinse liquid from the rinse nozzle 421 is stopped.

Next, a drying process is performed on the substrate 9 (step S17), and the center robot CR carries out the processed substrate 9 from the substrate processing apparatus 1 (step S18).

As described above, according to the substrate processing apparatus 1B, the static eliminating liquid having a high specific resistance value is supplied to the substrate 9 while the resistance value of the conduction path R1 is high. Therefore, the substrate 9 can be slowly and gradually neutralized. In other words, it is possible to eliminate electricity from the substrate 9 while avoiding a large current generated in the substrate 9 and reducing or avoiding damage to the substrate 9.

Further, according to the substrate processing apparatus 1B, the chemical liquid process is performed after the substrate 9 is neutralized. Therefore, in this chemical liquid process, even if a chemical liquid with a low specific resistance value is supplied to the substrate 9, a large current between the chemical liquid and the substrate 9 due to charging can be reduced or avoided. Therefore, damage to the substrate 9 during the chemical process can also be reduced or avoided.

Note that in the chemical liquid process, when an oxide film is formed using SPM as the chemical liquid, silicon is exposed on the main surface of the substrate 9 by, for example, dry etching in the previous process. In the chemical process, an oxide film is formed on this silicon.

<Multiple static eliminators>
In the above example, the substrate 9 is charged by a pre-process such as dry etching, and is carried into the substrate processing apparatus 1 in a charged state. Since the amount of charge on the substrate 9 caused by dry etching is relatively large, the substrate processing apparatus 1 eliminates the charge on the substrate 9 using a static eliminator having a large specific resistance value. Thereby, the amount of charge on the substrate 9 can be gradually reduced while reducing or avoiding damage to the substrate 9. However, the substrate 9 may not be fully charged when static electricity is removed using a static eliminator having a large specific resistance value. This is because when a static eliminator having a large specific resistance value is supplied to the substrate 9, the substrate 9 becomes charged due to friction between the static eliminator and the substrate 9, although not as much as dry etching. Further, in the static elimination process using a static eliminating liquid with a large specific resistance value, the time required for static elimination becomes long.

Therefore, the static eliminator supply unit 43 may sequentially supply the first static eliminator and the second static eliminator having a smaller specific resistance value than the first static eliminator to the substrate 9. That is, after the first static eliminator liquid removes static electricity from the substrate 9 slowly to a certain amount of charge, the second static eliminator liquid removes static electricity from the substrate 9 more quickly and to a smaller amount.

For example, pure water can be used as the first static eliminating liquid. As the second static eliminating liquid, for example, CO ₂ water can be used. The static eliminating liquid supply unit 43 may include a nozzle for the first static eliminating liquid and a nozzle for the second static eliminating liquid, or the static eliminating nozzle 431 may be used for both the first static eliminating liquid and the second static eliminating liquid. Moreover, when the rinse liquid supply part 42 supplies pure water as a rinse liquid, the rinse liquid supply part 42 may function as the static elimination liquid supply part 43 which supplies the 1st static elimination liquid (pure water). Below, the case where pure water is used as the first static eliminating liquid and the rinsing liquid will be described as an example.

<Substrate processing flow>
FIG. 12 is a flowchart showing an example of the flow of substrate processing. First, the central robot CR carries the substrate 9 into the substrate processing apparatus 1, and the substrate holding section 2 holds the substrate 9 (step S21). Note that here, the substrate 9 has been charged in the previous process.

FIG. 13 is a graph showing an example of the resistance value of the conduction path R1 according to each process. In the example of FIG. 13, the substrate holder 2 holds the substrate 9 in a state where the resistance value of the conduction path R1 is high. As a specific example, the chuck drive unit 23 moves the first chuck pin group to the holding position and moves the second chuck pin group to the release position.

Next, the substrate rotation mechanism 3 rotates the substrate 9 (step S22: rotation step). Specifically, the motor 32 rotates the shaft portion 31 and the substrate holding portion 2 around the rotation axis J1. As a result, the substrate 9 held by the substrate holder 2 rotates around the rotation axis J1.

Next, the static eliminating liquid supply section 43 (rinsing liquid supply section 42) supplies a first static eliminating liquid (pure water) to the upper surface of the rotating substrate 9 (step S23: first static eliminating step). Specifically, when the valve 423 opens the internal flow path of the supply pipe 422, the first static eliminating liquid (pure water) is discharged from the rinse nozzle 421 toward the center of the upper surface of the substrate 9. The first static eliminating liquid that has landed on the center of the substrate 9 is subjected to centrifugal force caused by the rotation of the substrate 9, spreads over the entire upper surface of the substrate 9, and scatters outward from the periphery of the substrate 9. Thereby, the substrate 9 is slowly neutralized by the first static eliminating liquid. Therefore, the amount of charge on the substrate 9 slowly decreases over time.

Further, in the first static elimination step (step S23), the substrate 9 is held by the first chuck pin group, and the resistance value of the conduction path R1 is high (see also FIG. 13). Therefore, the charges on the substrate 9 are less likely to flow to the grounding member via the conduction path R1. Therefore, damage to the substrate 9 caused by a large current flowing from the substrate 9 to the first chuck pin group can also be reduced or avoided.

For example, when the first static elimination processing time has elapsed from the start of supply of the first static eliminating liquid, the resistance value changing mechanism 5 reduces the resistance value of the conduction path R1 (step S24: resistance value changing step). As a specific example, the chuck drive unit 23 switches the chuck pins 22 that hold the substrate 9 from the first chuck pin group to the second chuck pin group. This reduces the resistance value of the conduction path R1.

Further, the static eliminating liquid supply unit 43 (rinsing liquid supply unit 42) stops supplying the first static eliminating liquid and supplies a second static eliminating liquid (for example, CO ₂ water) to the upper surface of the rotating substrate 9 (step S25). : 2nd static elimination step). Specifically, the valve 423 closes the internal flow path of the supply pipe 422, and the valve 433 opens the internal flow path of the supply pipe 432. As a result, the second static eliminating liquid (for example, CO ₂ water) is discharged from the static eliminating nozzle 431 to the center of the upper surface of the substrate 9 . The second static eliminating liquid that has landed on the center of the substrate 9 is subjected to centrifugal force caused by the rotation of the substrate 9, spreads over the entire upper surface of the substrate 9, and scatters outward from the periphery of the substrate 9. Thereby, the substrate 9 is neutralized by the second static eliminating liquid.

Note that the first static elimination processing time is such that even if the substrate 9 is held by the second chuck pin group, a large current does not flow from the substrate 9 to the second chuck pin group, and the second static elimination liquid is supplied to the substrate 9. This is a sufficient time for the substrate 9 to be neutralized to the extent that no large current flows from the substrate 9 to the second static eliminating liquid, and is set in advance, for example.

Since the chuck pin 22 holding the substrate 9 is switched to the chuck pin 22b having a smaller resistance value, the resistance value of the conduction path R1 is reduced (see also FIG. 13). Therefore, the electric charge on the substrate 9 easily flows to the grounding member via the conduction path R1, and the electric charge on the substrate 9 can be neutralized more quickly. Furthermore, since the static eliminator supplied to the substrate 9 is switched to the second static eliminator having a small specific resistance value, the charge on the substrate 9 is easily transferred to the second static eliminator, and the substrate 9 can be neutralized more quickly.

Moreover, since the specific resistance value of the second static eliminator is small, the substrate 9 is hardly charged even by friction between the second static eliminator and the substrate 9, and the amount of charge (surface potential) of the substrate 9 can be further reduced. .

For example, when the second static elimination processing time has elapsed from the start of supply of the second static elimination liquid, the valve 433 closes the internal flow path of the supply pipe 432. As a result, the supply of the second static eliminating liquid is stopped.

Next, the resistance value changing mechanism 5 increases the resistance value of the conduction path R1 again (step S26: resistance value changing step). As a specific example, the chuck drive unit 23 switches the chuck pins 22 that hold the substrate 9 from the second chuck pin group to the first chuck pin group.

Next, the chemical liquid supply unit 41 supplies a chemical liquid (diluted hydrofluoric acid) to the upper surface of the rotating substrate 9 (step S27: chemical liquid process). As a result, the chemical solution acts on the film to be etched on the upper surface of the substrate 9, thereby etching the film to be etched. In this chemical liquid process, since the resistance value of the conductive path R1 is high (see also FIG. 13), in-plane variations in etching can be reduced.

For example, when the chemical liquid processing time has elapsed from the start of the chemical liquid supply, the valve 413 closes the internal flow path of the supply pipe 412. As a result, the discharge of the chemical liquid from the chemical liquid nozzle 411 is stopped.

Next, the resistance value changing mechanism 5 reduces the resistance value of the conduction path R1 again (step S28: resistance value changing step). As a specific example, the chuck drive unit 23 switches the chuck pins 22 that hold the substrate 9 from the first chuck pin group to the second chuck pin group.

Next, the rinsing liquid supply unit 42 supplies a rinsing liquid (pure water) to the main surface of the rotating substrate 9 (step S29: rinsing process). As a result, the chemical liquid on the upper surface of the substrate 9 is replaced with the rinsing liquid. In this rinsing step, since the resistance value of the conduction path R1 is low (see also FIG. 13), charging of the substrate 9 due to friction between the rinsing liquid and the substrate 9, etc. can be reduced.

For example, when the rinsing processing time has elapsed from the start of supply of the rinsing liquid, the valve 423 closes the internal flow path of the supply pipe 422. As a result, the discharge of the rinse liquid from the rinse nozzle 421 is stopped.

Next, a drying process is performed on the substrate 9 (step S30), and the center robot CR carries out the processed substrate 9 from the substrate processing apparatus 1 (step S31).

According to this operation, in the initial stage of the static elimination process (first static elimination process), the substrate 9 is neutralized by the first static elimination liquid having a high specific resistance value while the resistance value of the conduction path R1 is high (see FIG. 13). reference). That is, in the initial stage when the amount of charge on the substrate 9 is large, the charge on the substrate 9 is gradually removed in order to reduce damage to the substrate 9 caused by the large current. Then, in the middle of the static elimination process, the resistance value of the conduction path R1 is reduced, and the static eliminating liquid is further switched to the second static eliminating liquid having a low specific resistance value (see also FIG. 13). In other words, in the latter stage of the static elimination process (second static elimination process) after the substrate 9 has been neutralized to some extent, even if the resistance value of the conduction path R1 and the specific resistance value of the static elimination liquid are lowered, a large current will not flow, so that conduction will not occur. While lowering the resistance value of the path R1, the second static eliminator is used to quickly eliminate static electricity from the substrate 9 (steps S24 and S25). Thereby, the time required for static elimination can be shortened. Furthermore, the amount of charge on the substrate 9 can be further reduced.

In the above example, when the first static elimination processing time has elapsed from the start of supply of the first static eliminating liquid, the static eliminating liquid to be supplied to the substrate 9 is switched from the first static eliminating liquid to the second static eliminating liquid, and the conduction path R1 The resistance value was reduced from a high resistance value to a low resistance value. However, only one of these may be performed. Specifically, the resistance value of the conduction path R1 may be maintained at a high resistance value also in the second static elimination step. By using the second static eliminator having a small specific resistance value, the substrate 9 can be neutralized more quickly, and the amount of charge on the substrate 9 can be further reduced. Alternatively, the first static eliminating liquid may be continuously supplied while the resistance value of the conduction path R1 is set to a low resistance value. In other words, it is not necessary to use the second static eliminator. By setting the conduction path R1 to a low resistance value, the substrate 9 can be neutralized more quickly, and the amount of charge on the substrate 9 can be further reduced.

Further, in the above example, the switching of the static eliminating liquid and the switching of the resistance value of the conduction path R1 are performed almost simultaneously, but these may be performed at different timings.

<Current measurement>
FIG. 14 is a diagram schematically showing an example of the configuration of the substrate processing apparatus 1C. The substrate processing apparatus 1C has the same configuration as the substrate processing apparatus 1B except for the presence or absence of the current sensor 8. The current sensor 8 measures the value of the current flowing through the conduction path R1, and outputs an electrical signal indicating the measurement result to the control unit 6.

As described above, when the substrate 9 is charged, the charge on the substrate 9 moves to the ground potential via the conduction path R1. That is, current i flows through the conduction path R1. It is considered that as the amount of charge on the substrate 9 decreases, the current i flowing through the conduction path R1 decreases.

Therefore, the control unit 6 determines the timing to stop supplying the static eliminating liquid based on the current i measured by the current sensor 8. Specifically, the control unit 6 determines whether the current i is less than the current reference value iref, for example, at predetermined time intervals. The control unit 6 causes the static eliminating liquid supply unit 43 to stop supplying the static eliminating liquid when the current i becomes less than the current reference value iref.

FIG. 15 is a flowchart showing an example of the static elimination process. This flow corresponds to a specific example of the static elimination step of step S13, for example. First, the static eliminating liquid supply unit 43 starts supplying the static eliminating liquid to the rotating substrate 9 (step S131). Next, the current sensor 8 measures the current i and outputs an electric signal indicating the measurement result to the control unit 6 (step S132: current measurement step). In this way, the measurement process using the current sensor 8 is performed in parallel with the static elimination process.

Next, the control unit 6 determines whether the current i measured by the current sensor 8 is less than the current reference value iref (step S133). The current reference value iref is a current value when it can be said that the amount of charge on the substrate 9 has become sufficiently small, and is set in advance, for example.

When the current i is greater than or equal to the current reference value iref, step S132 is executed again. When the current i is less than the current reference value iref, the static eliminating liquid supply unit 43 ends supplying the static eliminating liquid (step S134).

According to this, since the amount of charge on the substrate 9 is indirectly measured by the current i, it is possible to finish the static elimination process more reliably in a state where the amount of charge on the substrate 9 is sufficiently reduced.

In addition, when supplying the first static eliminator and the second static eliminator in this order, the timing of switching from the first static eliminator to the second static eliminator and the timing of ending the supply of the second static eliminator are also It may also be determined based on the current i. Specifically, a first current reference value and a second current reference value smaller than the first current reference value are set, and when the current i becomes less than the first current reference value, the supply of the first static eliminator is stopped. The supply of the second static eliminator may be started when the current i is lower than the second current reference value, and the supply of the second static eliminator may be ended.

According to this, the amount of charge on the substrate 9 is indirectly measured by the current i, and the timing to end the supply of the first static eliminating liquid and the timing to start the supply of the second static eliminating liquid are determined. In other words, the timing of switching the static eliminating liquid is determined based on the amount of charge on the substrate 9. Therefore, the static eliminating liquid can be switched to the second static eliminating liquid more reliably in a state in which the amount of charge on the substrate 9 is reduced to such an extent that a large current is not generated even if the second static eliminating liquid is supplied. Therefore, a large current generated in the substrate 9 can be more reliably avoided.

Even when adopting a timing different from the timing of switching the static eliminating liquid (start of step S25) as the timing of switching the resistance value of the conduction path R1 during static elimination (step S24), the resistance value is changed based on the current i. The switching timing may be determined. More specifically, a third current reference value larger than the second current reference value is set, and when the current i falls below the third current reference value, the resistance value of the conduction path R1 is changed from a high resistance value to a low resistance value. May be reduced to a value. According to this, it is possible to more reliably reduce the resistance value of the conduction path R1 while the amount of charge on the substrate 9 is reduced to the extent that a large current does not occur even if the resistance value of the conduction path R1 is lowered. . Therefore, a large current generated in the substrate 9 can be more reliably avoided.

<Measurement of carry-in charge amount>
In the example of FIG. 1, the substrate processing system 100 is provided with a surface potential sensor 52. This surface potential sensor 52 measures the surface potential of the substrate 9 before the substrate 9 is carried into the substrate processing apparatus 1 . In the example of FIG. 1, the surface potential sensor 52 is provided on the substrate platform PASS. The surface potential sensor 52 is provided at a position facing the main surface of the substrate 9 placed on the substrate platform PASS. The surface potential sensor 52 measures the surface potential of the substrate 9 and outputs an electrical signal indicating the measurement result to the control unit 6. Note that the surface potential sensor 52 may be provided in the indexer robot IR or the center robot CR.

The surface potential sensor 52 may measure the surface potential at one location on the main surface of the substrate 9. Alternatively, the surface potential sensor 52 may measure the surface potential at multiple locations within the main surface of the substrate 9. Specifically, a displacement mechanism that changes the relative positional relationship between the surface potential sensor 52 and the substrate 9 is provided, and by moving the surface potential sensor 52 with respect to the substrate 9, the displacement mechanism within the main surface of the substrate 9 is Surface potential can be measured at multiple locations.

The control unit 6 determines whether a static elimination process is necessary based on the surface potential measured by the surface potential sensor 52. Note that when the surface potential sensor 52 measures the surface potential at a plurality of locations, it may be determined whether or not the static elimination step is necessary based on the statistical value (maximum value, minimum value, average value, etc.). As a specific example, the control unit 6 determines whether the surface potential (for example, the maximum value) is less than the first potential reference value Vref1. The first potential reference value Vref1 is a very small value, and is set in advance, for example. The control unit 6 determines that the static elimination process is unnecessary when the surface potential is less than the first potential reference value Vref1, and determines that the static elimination process is necessary when the surface potential is greater than or equal to the first potential reference value Vref1. It may be determined that there is.

Alternatively, when the control unit 6 determines that the static elimination process is necessary, it determines the type of static elimination liquid used in the static elimination process and the resistance value of the conduction path R1 in the static elimination process based on the surface potential. Good too. For example, the control unit 6 determines whether the surface potential is less than the second potential reference value Vref2. The second potential reference value Vref2 is set larger than the first potential reference value Vref1. More specifically, the second potential reference value Vref2 is such that even if the second static eliminator having a small specific resistance value is supplied to the substrate 9 when the surface potential is less than the second potential reference value Vref2, the conduction path R1 For example, it is set in advance so that a large current does not occur in the substrate 9 even if the resistance value is low.

The control unit 6 sets the resistance value of the conduction path R1 to a high resistance value while using the first static eliminating liquid having a high specific resistance value in the static eliminating process when the surface potential is equal to or higher than the second potential reference value Vref2. decided on. On the other hand, when the surface potential is less than the second potential reference value Vref2, in the static elimination step, the control unit 6 changes the resistance value of the conduction path R1 to a low resistance value while using the second static eliminating liquid having a low specific resistance value. It is decided that

FIG. 16 is a flowchart schematically showing an example of the above processing. First, the surface potential sensor 52 measures the surface potential V of the substrate 9 (step S41: potential measurement step). For example, the substrate 9 is transported to the substrate platform PASS by the indexer robot IR. The surface potential sensor 52 measures the surface potential V of the substrate 9 carried into the substrate platform PASS, and outputs an electric signal indicating the measurement result to the control unit 6. The substrate 9 after measurement is carried out from the substrate platform PASS by the center robot CR.

Next, the control unit 6 determines whether the surface potential V (for example, the maximum value) measured by the surface potential sensor 52 is less than the first potential reference value Vref1 (step S42). When the surface potential V is less than the first potential reference value Vref1, the control unit 6 executes the first substrate processing shown in FIG. 6 (step S43). That is, when the surface potential V is less than the first potential reference value Vref1, the substrate 9 is hardly charged, so the control unit 6 determines that the static elimination step is unnecessary, and executes the first substrate treatment. In the first substrate treatment, the static elimination process for the substrate 9 is not performed, and the chemical solution process (step S3) in a state where the resistance value of the conduction path R1 is high and the rinsing process (step S5) in a state where the resistance value of the conduction path R1 is low. are performed in this order.

When the surface potential V is greater than or equal to the first potential reference value Vref1, the control unit 6 determines whether the surface potential is less than the second potential reference value Vref2. When the surface potential V is equal to or higher than the second potential reference value Vref2, the control unit 6 determines that the substrate 9 is charged with a relatively large amount of charge, and performs the second substrate treatment in FIG. 10 or the third substrate treatment in FIG. Substrate processing is performed (step S45). In both the second substrate processing and the third substrate processing, the substrate holding section 2 receives the substrate 9 from the center robot CR in a state where the resistance value of the conduction path R1 is high (steps S11, S21), and the static eliminating liquid supply section 43 supplies a static eliminating liquid (first static eliminating liquid) with a high specific resistance value to the substrate 9 to perform a static eliminating process (first static eliminating process) (steps S13, S23). This allows the substrate 9 to be slowly neutralized while reducing or avoiding large currents generated in the substrate 9.

When performing the third substrate treatment (FIG. 12), after the first static elimination step (step S23), the resistance value of the conduction path R1 is reduced (step S24), and a second static elimination liquid with a small specific resistance value is used. A second static elimination step (step S25) is performed. Thereby, the amount of charge can be further reduced while neutralizing the charge on the substrate 9 more quickly.

After the static elimination step, in both the second substrate treatment and the third substrate treatment, a chemical solution step (steps S14, S27) is performed in a state where the resistance value of the conduction path R1 is high, and a chemical solution step is performed in a state where the resistance value of the conduction path R1 is low. The rinsing steps (steps S16 and S29) are performed in this order.

Referring again to FIG. 16, when the surface potential V is less than the second potential reference value Vref2, the control unit 6 determines that the substrate 9 is charged with a relatively small amount of charge, and performs the fourth substrate processing step. (Step S46). FIG. 17 is a flowchart schematically showing an example of the fourth substrate processing step. First, the central robot CR carries the substrate 9 into the substrate processing apparatus 1, and the substrate holding section 2 holds the substrate 9 (step S51: holding step). Note that here, the substrate 9 is charged with a small amount of charge in a previous process before being carried into the substrate processing apparatus 1.

FIG. 18 is a graph showing an example of the resistance value of the conduction path R1 according to each process. In the example of FIG. 18, the substrate holder 2 holds the substrate 9 in a state where the resistance value of the conduction path R1 is low. As a specific example, the chuck drive unit 23 moves a first chuck pin group made of a low-resistance material to a release position, and moves a second chuck pin group to a holding position. Thereby, the resistance value of the conduction path R1 can be lowered. Here, since the amount of charge on the substrate 9 is small, even if the resistance value of the conduction path R1 is reduced, a large current will not be generated from the substrate 9 to the chuck pin 22b.

Next, the substrate rotation mechanism 3 rotates the substrate 9 (step S52: rotation step). Specifically, the motor 32 rotates the shaft portion 31 and the substrate holding portion 2 around the rotation axis J1. As a result, the substrate 9 held by the substrate holder 2 rotates around the rotation axis J1.

Next, the static eliminating liquid supply unit 43 supplies a second static eliminating liquid (for example, CO ₂ water) with a low specific resistance value to the upper surface of the rotating substrate 9 (step S53: static eliminating process). Thereby, the charge on the substrate 9 can be removed more quickly and to a smaller amount.

For example, when the static elimination processing time has elapsed from the start of supply of the static eliminating liquid, the valve 433 closes the internal flow path of the supply pipe 432. As a result, discharge of the static eliminating liquid from the static eliminating nozzle 431 is stopped.

Next, the resistance value changing mechanism 5 increases the resistance value of the conduction path R1 (step S54: resistance value changing step). Specifically, the chuck drive unit 23 switches the chuck pins 22 that hold the substrate 9 from the second chuck pin group to the first chuck pin group. This increases the resistance value of the conduction path R1.

Next, the chemical liquid supply unit 41 supplies a chemical liquid (dilute hydrofluoric acid) to the upper surface of the rotating substrate 9 (step S55: chemical liquid process). As a result, the chemical solution acts on the film to be etched on the upper surface of the substrate 9, thereby etching the film to be etched. Even in this chemical process, since the resistance value of the conductive path R1 is high (see also FIG. 18), in-plane variations in etching can be reduced.

For example, when the chemical liquid processing time has elapsed from the start of the chemical liquid supply, the valve 413 closes the internal flow path of the supply pipe 412. As a result, the discharge of the chemical liquid from the chemical liquid nozzle 411 is stopped.

Next, the resistance value changing mechanism 5 reduces the resistance value of the conduction path R1 (step S56: resistance value changing step). Specifically, the chuck drive unit 23 switches the chuck pins 22 that hold the substrate 9 from the first chuck pin group to the second chuck pin group. This reduces the resistance value of the conduction path R1.

Next, the rinsing liquid supply unit 42 supplies the rinsing liquid to the upper surface of the rotating substrate 9 (step S57: rinsing step). As a result, the chemical liquid on the upper surface of the substrate 9 is replaced with the rinsing liquid. In this rinsing step, since the resistance value of the conduction path R1 is low (see also FIG. 18), charging of the substrate 9 due to friction between the rinsing liquid and the substrate 9, etc. can be reduced.

For example, when the rinsing processing time has elapsed from the start of supply of the rinsing liquid, the valve 423 closes the internal flow path of the supply pipe 422. As a result, the discharge of the rinse liquid from the rinse nozzle 421 is stopped.

Next, a drying process is performed on the substrate 9 (step S58), and the center robot CR carries out the processed substrate 9 from the substrate processing apparatus 1 (step S59).

According to this operation, since the amount of charge on the substrate 9 is small, in the static elimination process (step S53), the resistance value of the conduction path R1 is made low while using the second static eliminating liquid having a small specific resistance value. Therefore, the charge on the substrate 9 can be removed more quickly and to a smaller amount.

In addition, in the static elimination step (step S53), a static elimination liquid having a small specific resistance value was used, and the resistance value of the conduction path R1 was set to a low resistance value. However, only one of these may be performed. Specifically, the resistance value of the conduction path R1 may be maintained at a high resistance value also in the static elimination process (step S53). By using the second static eliminator having a small specific resistance value, the substrate 9 can be neutralized more quickly, and the amount of charge on the substrate 9 can be further reduced. Alternatively, in the static eliminating step (step S53), the first static eliminating liquid having a large specific resistance value may be supplied while the resistance value of the conduction path R1 is set to a low resistance value. This also allows the conduction path R1 to have a low resistance value, thereby allowing the substrate 9 to be neutralized more quickly, and further reducing the amount of charge on the substrate 9.

As described above, the substrate processing apparatuses 1, 1A to 1C have been described in detail, but the above description is an example in all aspects, and the substrate processing apparatus is not limited thereto. It is understood that countless variations not illustrated can be envisioned without departing from the scope of this disclosure. The configurations described in each of the above embodiments and modifications can be appropriately combined or omitted as long as they do not contradict each other.

For example, in the above example, the processing liquid supply section 4 supplies the processing liquid (including the static eliminating liquid, the chemical solution, and the rinsing liquid) to the upper surface of the substrate 9 , but it may also supply the processing liquid to the lower surface of the substrate 9 . Further, in the above example, the processing liquid supply unit 4 supplies the processing liquid to the center of the substrate 9, but it may also supply the processing liquid only to the peripheral portion of the substrate 9.

Further, in the above example, the amount of charge on the substrate 9 before being carried in is detected by the surface potential sensor 52, but this is not necessarily the case. The control unit 6 may acquire information that reflects the amount of charge on the substrate 9. The acquisition source may be, for example, an upstream processing device or a central control center. Alternatively, a worker may input the information to an input device (not shown), and the input device may output the information to the control unit 6.

1,1A to 1C Substrate processing apparatus 2 Substrate holder 22 Chuck pin 22a First chuck pin (chuck pin)
22b Second chuck pin (chuck pin)
23 Chuck drive unit 3 Rotation mechanism (substrate rotation mechanism)
411 Chemical liquid nozzle 421 Rinse nozzle 431 Static elimination nozzle 8 Current sensor

Claims (19)

a holding step of holding the periphery of the substrate with multiple chuck pins;
a potential measuring step of measuring the surface potential of the substrate;
a rotation step of rotating the substrate around a rotation axis perpendicular to the main surface of the substrate held by the chuck pin;
a chemical liquid step of supplying a chemical liquid to the main surface of the rotating substrate;
After the chemical solution step, a resistance value changing step of reducing the resistance value of a conductive path between the substrate held by the chuck pin and ground;
A rinsing step of supplying a rinsing liquid to the main surface of the rotating substrate in a state where the resistance value of the conductive path is reduced. The substrate processing method according to claim 1,
A substrate processing method, further comprising a static eliminating step that is executed when the surface potential measured in the potential measuring step is equal to or higher than a reference value, and supplies a static eliminating liquid to the main surface of the rotating substrate. The substrate processing method according to claim 1 or 2 ,
The substrate processing method, wherein the chemical solution contains SPM or hydrofluoric acid. The substrate processing method according to any one of claims 1 to 3 ,
In the chemical liquid step, holding the substrate with a plurality of first chuck pins among the chuck pins,
In the resistance value changing step, the chuck pins that hold the substrate are switched from the first chuck pins to a plurality of second chuck pins having a smaller resistance value than the first chuck pins. 5. The substrate processing method according to claim 4 ,
A substrate processing method, wherein the first chuck pin has a resistance value of 1 MΩ or more, and the second chuck pin has a resistance value of 10Ω or less. The substrate processing method according to any one of claims 1 to 5 ,
In the chemical liquid step, a resistance value of a variable resistor between the chuck pin and the ground is set as a first resistance value,
The substrate processing method includes reducing the resistance value of the variable resistor to a second resistance value smaller than the first resistance value in the resistance value changing step. a holding step of holding the periphery of the substrate with multiple chuck pins;
a rotation step of rotating the substrate around a rotation axis perpendicular to the main surface of the substrate held by the chuck pin;
a chemical liquid step of supplying a chemical liquid to the main surface of the rotating substrate;
After the chemical solution step, a resistance value changing step of reducing the resistance value of a conductive path between the substrate held by the chuck pin and ground;
a rinsing step of supplying a rinsing liquid to the main surface of the rotating substrate in a state where the resistance value of the conduction path is reduced;
Equipped with
A substrate processing method further comprising, before the chemical solution step, a static eliminating step of supplying a static eliminating liquid to the substrate held by the chuck pin. 8. The substrate processing method according to claim 7 ,
A substrate processing method, wherein the static elimination step is started in a state where the resistance value of the conduction path is higher than the resistance value of the conduction path in the rinsing step. 9. The substrate processing method according to claim 8 ,
A substrate processing method, wherein the resistance value of the conductive path is reduced during the static elimination step. 9. The substrate processing method according to claim 8 ,
Further comprising a current measurement step that is executed in parallel with the static elimination step and measures the current flowing through the conduction path,
A substrate processing method, in which the resistance value of the conduction path is reduced when the current falls below a second current reference value in the static elimination step. The substrate processing method according to any one of claims 7 to 9 ,
Further comprising a potential measuring step of measuring the surface potential of the substrate before the static eliminating step,
When the surface potential is larger than the potential reference value, the resistance value of the conduction path in the static elimination step is determined to be a third resistance value, and when the surface potential is smaller than the potential reference value, the resistance value in the static elimination step is determined. A substrate processing method, further comprising the step of determining a resistance value of the conductive path to a fourth resistance value lower than the third resistance value. The substrate processing method according to any one of claims 7 to 9 ,
Further comprising a potential measuring step of measuring the surface potential of the substrate before the static eliminating step,
When the surface potential is larger than the potential reference value, a first static eliminating liquid is supplied as the static eliminating liquid in the static eliminating process, and when the surface potential is smaller than the potential reference value, the static eliminating liquid is supplied in the static eliminating process. A substrate processing method further comprising the step of supplying, as a liquid, a second static eliminator having a lower specific resistance value than the first static eliminator. The substrate processing method according to any one of claims 7 to 9 and 11 ,
In the static eliminating step, after supplying a first static eliminating liquid as the static eliminating liquid, a second static eliminating liquid having a lower specific resistance value than the first static eliminating liquid is supplied to the substrate as the static eliminating liquid. 14. The substrate processing method according to claim 13 ,
Further comprising a current measurement step that is executed in parallel with the static elimination step and measures the current flowing through the conduction path,
In the static eliminating step, when the current falls below a current reference value, the supply of the first static eliminating liquid is stopped and the supply of the second static eliminating liquid is started. The substrate processing method according to any one of claims 7 to 9 and claims 11 to 13 ,
Further comprising a current measurement step that is executed in parallel with the static elimination step and measures the current flowing through the conduction path,
A substrate processing method, wherein, in the static eliminating step, supply of the static eliminating liquid is terminated when the current falls below a current reference value. The substrate processing method according to any one of claims 7 to 15 ,
A substrate processing method further comprising a drying step of performing dry etching on the substrate before the static elimination step. The substrate processing method according to any one of claims 1 to 16 ,
A substrate processing method, wherein silicon is exposed on the main surface of the substrate. A substrate processing device,
a plurality of first chuck pins that move between a holding position in which the substrate is held by contacting the periphery of the substrate, and a release position in which the holding position of the substrate is released by moving away from the periphery of the substrate; and the first chuck pins. has a resistance value smaller than , and moves between a holding position in which the substrate is held by contacting the periphery of the substrate, and a release position in which the holding position of the substrate is released by moving away from the periphery of the substrate. a substrate holder including a second chuck pin;
a rotation mechanism that rotates the substrate holder around a rotation axis perpendicular to a main surface of the substrate held by the substrate holder;
a chuck drive unit that independently drives the first chuck pin and the second chuck pin;
a chemical liquid nozzle that supplies a chemical liquid to the main surface of the substrate held by the substrate holding unit;
a rinsing nozzle that supplies a rinsing liquid to the main surface of the substrate held by the substrate holder ;
a surface potential sensor that measures the surface potential of the substrate;
a control unit that determines whether to supply a static eliminating liquid to the main surface of the substrate based on the surface potential measured by the surface potential sensor;
Equipped with
The control unit causes the chemical solution to be supplied from the chemical solution nozzle to the main surface of the substrate while the substrate is held by the first chuck pin, and causes the rinse to be performed while the substrate is held by the second chuck pin. A substrate processing apparatus that supplies the rinsing liquid to the main surface of the substrate from a nozzle . The substrate processing apparatus according to claim 18 ,
a static eliminating nozzle that supplies static eliminating liquid to the main surface of the substrate held by the substrate holding unit;
A substrate processing apparatus further comprising: a current sensor that measures a current flowing through a conduction path between the substrate holder and ground.

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