JP6808960B2 - Processing liquid supply device - Google Patents

Description

The present invention relates to a processing liquid supply device provided with opposed electrodes to each other to form a flow path of the treatment liquid.

In the photolithography process of forming a resist pattern on a semiconductor wafer (hereinafter referred to as a wafer) which is a substrate, a processing liquid is discharged from a nozzle to the wafer in a processing liquid supply device to perform processing, and a defect is found in the resist pattern. In order to prevent the generation, it is required to collect and remove foreign substances contained in the treatment liquid. In collecting the foreign matter, it is conceivable to provide an electrode in the storage tank of the treatment liquid and attract the foreign matter to the electrode by the electric charge of the foreign matter to collect the dust.

However, since such a storage tank has a relatively large capacity, there is a concern that the manufacturing cost of the device will increase due to the provision of many electrodes or the complicated structure of the electrodes in order to sufficiently collect dust. There is. Further, in order to reliably prevent the supply of foreign matter to the wafer, it is desirable to collect dust at a position close to the nozzle. Therefore, as described in Patent Document 1, an electrostatic precipitator module provided with a pair of electrodes constituting a treatment liquid supply path connecting the storage tank and the nozzle is provided in the apparatus, and the treatment liquid flows through the supply path. In the meantime, it is being studied to apply a DC voltage to the electrode from a DC power supply to collect foreign matter in this supply path.

Japanese Unexamined Patent Publication No. 2012-222238

By the way, as the conductive path connecting the DC power supply and the electrode forming the supply path of the treatment liquid, for example, a metal such as copper having a relatively low resistance is used. However, it is required that the electrode is made of a material different from that of the above-mentioned conductive path so that metal contamination of the treatment liquid does not occur. Due to the different materials, the contact resistance between the electrode and the conductive path becomes relatively high. On the other hand, it is necessary to secure an electric field having sufficient strength between the electrodes so that foreign matter can be sufficiently collected. For this reason, the materials used as electrodes are limited, but in order to reduce the manufacturing cost of the equipment and increase the degree of freedom in design, it is required that various materials can be used as electrodes. ing.

The present invention has been made in view of such circumstances, and an object of the present invention is to collect electrostatic precipitators provided with a first electrode and a second electrode which face each other and are configured as a flow path for a treatment liquid. It is an object of the present invention to provide a technique capable of increasing the degree of freedom in selecting a material of an electrode that can be used in an apparatus.

The processing liquid supply device of the present invention has a processing liquid supply source and
The mounting part on which the board is mounted and
A nozzle for processing the substrate by supplying the processing liquid supplied by circulating the processing liquid supply path from the source to the substrate placed on the mounting portion,
The first electrode and the second electrode, which are opposed to each other and are each composed of a planar body and form a flow path forming a part of the processing liquid supply path between them,
An insulating support member that partitions the flow path together with the first electrode and the second electrode and is interposed between the peripheral edges of the first electrode and the second electrode.
An inflow port and an outflow port for the treatment liquid provided on the support member so as to face the flow path,
A first planar surface that is laminated in contact with the outer surface of the first electrode, is of a material different from that of the first electrode, connects the power supply unit and the first electrode, and forms a first conductive path. With the body
It is laminated in contact with the outer surface of the second electrode, is made of a material different from that of the second electrode, forms a second conductive path connecting the power supply unit and the second electrode, and has an electric field in the flow path. With a second planar body for forming
To be equipped.

According to the present invention, an insulating support member is interposed between the first electrode and the second electrode, which are opposed to each other and are made of planar bodies, and the peripheral portions of the first electrode and the second electrode. A flow path of the treatment liquid is formed by, and is laminated on the outer surface side of the first electrode and the outer surface side of the second electrode, respectively, and electrically connects the power supply unit, the first electrode, and the second electrode, respectively. A planar body for a first conductive path and a planar body for a second conductive path for connection are provided. With such a configuration, the contact area between the electrodes and the conductive path can be made relatively large, so that the contact resistance between these electrodes and the conductive path can be suppressed. As a result, a sufficient electric field can be formed between the electrodes, so that the degree of freedom in selecting the material constituting the electrodes can be increased.

It is a longitudinal side view of the resist coating apparatus which concerns on embodiment of this invention. It is a block diagram of the piping which comprises the resist coating apparatus. It is a perspective view of the electrostatic precipitator module provided in the said pipe. It is an exploded perspective view of the electrostatic precipitator module. It is a longitudinal side view of the electrostatic precipitator module. It is a side view of the electrostatic precipitator module. It is a schematic diagram of the electrode plate which constitutes the electrostatic precipitator module. It is a circuit diagram which shows the electrical equivalent circuit of the electrostatic precipitator module. It is explanatory drawing which shows the state that the foreign matter is collected by the electrode plate. It is explanatory drawing which shows the state that the foreign matter is collected by the electrode plate. It is explanatory drawing which shows the state that the foreign matter is removed from the electrode plate. It is explanatory drawing which shows the state that the foreign matter is removed from the electrode plate. It is a top view of the frame which constitutes the electrostatic precipitator module. It is a circuit diagram which shows the electrical equivalent circuit of the electrostatic precipitator module of another configuration. It is a schematic exploded perspective view of the electrostatic precipitator module of the other configuration. It is a top view of the frame body and the conductive plate which make up the electrostatic precipitator module of another structure. It is a cross-sectional plan view of the electrostatic precipitator module of further other configurations. It is a schematic cross-sectional plan view which shows the electrostatic precipitator module of still another structure. It is a schematic longitudinal side view which shows the electrostatic precipitator module of still another structure. It is a top view for showing the arrangement of the port provided in the electrostatic precipitator module. It is a top view for showing the relationship between the size of the electrode plate and the conductive plate provided in the electrostatic precipitator module. It is explanatory drawing which shows the result of the evaluation test which concerns on this invention. It is explanatory drawing which shows the result of the evaluation test which concerns on this invention.

The resist coating device 1, which is an embodiment of the processing liquid supply device according to the present invention, will be described with reference to the longitudinal side view of FIG. The resist coating apparatus 1 supplies a resist to the surface of the wafer W to be processed to form a resist film. Further, the resist coating apparatus 1 performs a pre-wetting treatment of supplying thinner, which is an organic solvent, as a treatment liquid for improving the wettability of the resist on the surface of the wafer W before supplying the resist. The resist coating device 1 incorporates an electrostatic precipitator that electrically collects foreign matter in the thinner as a module.

In the figure, reference numeral 11 denotes a spin chuck forming a processing portion, which attracts the central portion of the back surface of the wafer W to hold the wafer W horizontally. Reference numeral 12 denotes a rotation mechanism, which rotates the wafer W held by the spin chuck 11 around a vertical axis. Three elevating pins 13 (only two are shown in the figure) are provided to elevate and lower the wafer W between the spin chuck 11 and a transfer mechanism (not shown).

In the figure, reference numeral 14 denotes a cup, which is provided so as to surround the wafer W held by the spin chuck 11. A drainage port 15 is opened on the bottom surface of the cup 14, and resist and thinner spilled from the wafer W into the cup 14 are removed from the drainage port 15. Further, the exhaust pipe 16 is provided so as to project upward from the bottom surface of the cup, and exhausts the inside of the cup 14.

Reference numeral 17 in the figure is a resist discharge nozzle, which discharges the resist vertically downward. Reference numeral 18 in the figure is a thinner discharge nozzle, which discharges thinner vertically downward. The resist discharge nozzle 17 and the thinner discharge nozzle 18 are configured to be movable between a center portion of the wafer W arranged in the cup 14 and a standby area provided outside the plan view of the cup 14 by a drive mechanism (not shown). Has been done. The resist discharge nozzle 17 is connected to a resist supply mechanism 19 for supplying a resist to the nozzle 17. Further, the thinner discharge nozzle 18 is connected to a thinner supply mechanism 2 for supplying thinner to the nozzle 18.

Hereinafter, the thinner supply mechanism 2 will be described with reference to FIG. The thinner supply mechanism 2 includes a thinner storage tank 21 which is a supply source of a treatment liquid in which thinner is stored. The upstream end of the thinner supply pipe 22 forming the thinner supply path is connected to the storage tank 21, and the downstream end of the thinner supply pipe 22 is connected to the thinner discharge nozzle 18. An intermediate tank 23, a pump 24, a filter 25, a valve V1, an electrostatic precipitator module 3, and a valve V2 are interposed in the thinner supply pipe 22 from the thinner storage tank 21 toward the downstream side in this order. Further, the thinner supply pipe 22 will be further described. It is branched into two on the downstream side of the valve V1 and connected to the electrostatic precipitator module 3, and two branched pipes are branched on the downstream side of the electrostatic precipitator module 3. It merges and is connected to valve V2.

The intermediate tank 23 has a role as a buffer tank for temporarily storing thinner supplied from the thinner storage tank 21 to the downstream side, and even when the thinner supplied from the thinner storage tank 21 is exhausted, the intermediate tank 23 has a role. The thinner stored in the thinner can be supplied to the thinner discharge nozzle 18. In the figure, 26 is an exhaust pipe for venting provided in the upper part of the intermediate tank 23 in order to exhaust the atmosphere in the intermediate tank 23.

The pump 24 pumps thinner from the thinner storage tank 21 to the thinner discharge nozzle 18 or the waste liquid pipe 27 described later. The filter 25 removes foreign matter from the thinner by filtering the thinner flowing from the upstream side to the downstream side of the filter 25. The electrostatic precipitator module 3 electrically removes foreign matter contained in thinner toward the downstream side. That is, the foreign matter that cannot be completely removed by the filter 25 is collected by the electrostatic precipitator module 3 and is removed from the thinner flowing through the supply pipe 22.

The upstream end of the waste liquid pipe 27 is connected to the thinner supply pipe 22 which is merged into one in the front stage of the valve V1 as described above. The downstream end of the waste liquid pipe 27 opens to the waste liquid portion 28, and a valve V3 is interposed in the waste liquid pipe 27. Foreign matter collected by the electrostatic precipitator module 3 during the processing of the wafer W is flowed from the waste liquid pipe 27 to the waste liquid portion 28 and removed. The resist supply mechanism 19 will also be described supplementarily. The electrostatic precipitator module 3 and the waste liquid pipe 27 are not provided, and the resist is stored in the storage tank 21 instead of thinner. It is configured in the same manner as the thinner supply mechanism 2 except that the thinner supply mechanism 2 is used.

Subsequently, the configuration of the electrostatic precipitator module 3 will be described with reference to a perspective view of FIG. 3, an exploded perspective view of FIG. 4, a longitudinal side view of FIG. 5, and a schematic longitudinal side view of FIG. In FIGS. 3, 5 and 6, the flow direction of thinner is indicated by an arrow. The electrostatic precipitator module 3 includes an upright rectangular frame 31 that is elongated in the lateral direction. The frame 31 is made of an insulator, and specifically, for example, PTFE (polytetrafluoroethylene) or the like. It is composed of resin. Further, the frame 31 is vertically symmetrical and symmetrical when the length direction is the left-right direction.

The peripheral edge of the opening surrounded by the frame 31 is formed so as to substantially follow the outer edge of the frame 31. Therefore, this opening is formed in a horizontally long and substantially rectangular shape. This opening is partitioned from the outside of the frame 31 by a pair of electrode plates 52, which will be described later, and is a flow path through which thinner flows, and a flat collection in which foreign matter is collected by forming an electric field. It is configured as a dust region 30.

The one-sided side and the other-sided side of the frame body 31 in the thickness direction (opening direction of the opening) are configured in the same manner as each other, and a reference numeral 32 is attached to the opening edge portion surrounding the opening. The outside of the opening edge portion 32 is configured as a connection region 33 for surrounding the opening edge portion 32 and for attaching a reinforcing plate 56 described later. The opening edge portion 32 and the connecting region 33 are partitioned by a step, and the opening edge portion 32 is formed lower than the connecting region 33. The connection area 33 is provided with a through hole 34 formed in the thickness direction of the frame body 31. A large number of through holes 34 are arranged along the dust collecting region 30.

Two openings are formed on one side end surface of the frame 31 in the length direction so as to be separated from each other in the vertical direction. Each opening is perforated along the length direction of the frame body 31 and faces the dust collecting region 30. These openings are configured as thinner inflow ports 35 and are connected to the thinner supply pipe 22 described with reference to FIG. 2 via a joint 36 provided on the outside of the frame 31.

Two openings corresponding to the inflow port 35 are provided on the side end surface on the other side in the length direction of the frame 31 so as to be separated from each other in the vertical direction, and are configured as thinner outflow port 37. Since the frame 31 has the symmetry as described above, the outflow port 37 is perforated along the length direction of the frame 31 like the inflow port 35 to face the dust collection region 30, and the inflow port 35 and the inflow port 35. They are arranged so as to face each other. Further, since the inflow port 35 and the outflow port 37 are provided at one end and the other end of the frame 31 in the length direction in this way, the length direction of the frame 31, that is, the length direction of the dust collection region 30 However, it becomes the flow direction of thinner. The outflow port 37 is connected to the thinner supply pipe 22 via a joint 38 like the inflow port 35.

The reason why two inflow ports 35 are provided in the vertical direction orthogonal to the length direction of the flow path and the arrangement direction of the electrode plates 52 (opening direction of the frame 31) will be described. Since the dust collecting region 30 is relatively large in the vertical direction when viewed from the inflow port 35, the flow path is expanded when viewed in the flow direction of thinner. Therefore, a pressure loss occurs between the inflow port 35 and the dust collecting region 30. If the expansion of the flow path seen from the inflow port 35 is too large, the above pressure loss becomes large, and a thinner vortex is formed in the vicinity of the inflow port 35 in the dust collection region 30. When a vortex is formed, a region where thinner does not easily flow is generated, and the dust collecting effect of foreign matter in the dust collecting region 30 may be reduced. Therefore, two inflow ports 35 are provided in the vertical direction so as to suppress the thinner region extending in the vertical direction from one inflow port 35. That is, the formation of the eddy current is suppressed by suppressing the expansion of the flow path seen from the inflow port 35. In addition, three or more inflow ports 35 may be provided.

Further, when the outflow port 37 is viewed from the dust collecting region 30, the degree of reduction of the flow path in the vertical direction is relatively large. Since the flow path is reduced in this way, a pressure loss also occurs between the outflow port 37 and the dust collection area 30, and if the degree of reduction is too large, the outflow occurs in the dust collection area 30. A thinner vortex is formed near the port 37. Therefore, a plurality of outflow ports 37 are provided in the vertical direction, and the upper and lower ranges of the dust collection area 30 through which thinner flowing into one outflow port 37 flows are suppressed to be small, that is, the reduction of the flow path as seen from the dust collection area 30 is suppressed. This suppresses the formation of eddy currents. In addition, three or more outflow ports 37 can be provided.

A hole 41 for venting gas is drilled in the upper part of the frame 31 in the vertical direction so as to open near one end side (the side where the inflow port 35 is provided) of the dust collecting region 30 in the length direction. A vent pipe 43 is connected to 41 via a joint 42 provided on the upper side of the frame 31. A valve V4 is provided in the pipe 43. The valve V4 is closed when the wafer W is processed, but is opened at an appropriate timing when the wafer W is not processed, and the valves V1 and V1 shown in FIG. 2 are closed in the dust collecting region 30. Thinner is supplied and venting is performed. Further, in order to efficiently perform this venting, the frame 31 is placed on the horizontal floor surface 44 shown in FIG. 6 so that one end side of the dust collecting region 30 in the length direction is the other end of the dust collecting region 30 in the length direction. It is installed at an angle so that it is higher than the side.

A sealing member 51, an electrode plate 52, a conductive plate 53, a conductive plate 54, an insulating sheet 55, and a reinforcing plate 56 are provided on one side and the other side of the frame 31 from the lower side (the side closer to the frame 31). The frame 31 is provided so as to be laminated in this order toward the upper side. That is, assuming that the seal member 51, the electrode plate 52, the conductive plate 53, the conductive plate 54, the insulating sheet 55, and the reinforcing plate 56 are a set of one member, the frame 31 is sandwiched between the two sets. Further, the plates 52, 53, 54, 56 on one side of the frame 31 and the plates 52, 53, 54, 56 on the other side are provided on the frame 31 so as to face each other and be parallel to each other. ing.

Explaining each of the above-mentioned members provided on the frame body 31, the seal member 51 is a square ring-shaped elastic body, and is provided so as to overlap the above-mentioned opening edge portion 32 and surround the dust collecting region 30. The seal member 51 is in close contact with the frame 31 and the electrode plate 52, and has a role of preventing liquid leakage from the dust collecting region 30.

The peripheral portion of the electrode plate 52, which is a planar body, is formed in a rectangular shape so as to follow the opening edge portion 32 of the frame body 31, and is provided on the opening edge portion 32. That is, the frame body 31 is interposed between the peripheral edge portion of one electrode plate 52 (first electrode) and the peripheral edge portion of the other electrode plate 52 (second electrode), and these two electrode plates 52. Is configured as a support member that supports them in a state of being separated from each other. As will be described later, a DC voltage is applied to the electrode plate 52, one electrode plate 52 serves as a positive electrode, the other electrode plate 52 serves as a negative electrode, and these electrode plates 52 function as parallel plate electrodes to cover the dust collection region 30. An electric field is formed. Since the opening of the frame 31 is closed by the electrode plate 52 and the dust collecting region 30 is formed, the electrode plate 52 and the frame 31 also serve as a flow path forming member for forming a thinner flow path. Have. The electrode plate 52 is made of a conductor such as silicon, which has no risk of metal contamination of thinner.

For example, the electrode plate 52 is washed with an alkaline cleaning solution containing ammonia water or the like before being attached to the frame 31, so that the surface facing the dust collecting region 30 becomes uneven as shown in the schematic side view of FIG. It is formed. Explaining the reason why such unevenness formation processing is performed, the electrode plate 52 constitutes a capacitor, and the capacitance of this capacitor, that is, the magnitude of the electric field between the two electrode plates 52 is the surface area of the electrode plate 52. The larger the value, the larger the value. That is, by forming the unevenness as described above and increasing the surface area of the electrode, it is possible to increase the amount of foreign matter that can be adsorbed and reduce the frequency of removing the foreign matter from the electrode plate 52, which will be described later. .. If the surface of the electrode plate 52 can be roughened to form irregularities, the surface area can be increased. Therefore, a treatment such as sandblasting may be performed instead of the above cleaning treatment.

Subsequently, the conductive plate 53 will be described. The conductive plate 53 is configured to have the same shape as the electrode plate 52 in a plan view, for example. Then, the conductive plate 53 is provided on the opening edge portion 32 of the frame body 31 so that the peripheral edge portion thereof overlaps the peripheral edge portion of the electrode plate 52. The conductive plate 54 is also configured to have substantially the same shape as the electrode plate 52, for example, and is provided so that its peripheral edge portion overlaps the peripheral edge portion of the conductive plate 53. The difference between the conductive plate 54 and the conductive plate 53 is that a part of the upper side surface of the conductive plate 54 extends upward so as to form a connecting portion 57 connected to the DC power supply 64 described later. It can be mentioned that. To further explain the connection portion 57, the conductive plate 54 laminated on the conductive plate 53 as described above is located at a position higher than the step between the opening edge portion 32 and the connection region 33, and the connection portion 57 is described. Can be connected to the DC power supply 64 via the connecting portion 57 because the electrode plate 52 projects to the outside of the frame body 31.

In this way, the conductive plates 53 and 54 are laminated on the electrode plate 52 from the outer surface side of the dust collection region 30, and are planar for a conductive path that electrically connects the DC power supply 64 and the electrode plate 52. It is configured as a body, and the conductive plates 53 and 54 on one side of the frame 31 form the first conductive path, and the conductive plates 53 and 54 on the other side form the second conductive path. Further, the conductive plates 53 and 54 are made of a material different from the material constituting the electrode plate 52, for example, copper. The conductive plates 53 and 54 may be made of a conductor other than copper, for example, a metal such as aluminum. In addition to serving as a conductive path, the conductive plates 53 and 54 also have a role of suppressing damage or deformation of the electrode plate 52 due to the stress of thinner flowing through the dust collecting region 30 when in contact with the electrode plate 52.

The insulating sheet 55 has a role of insulating the conductive plate 54 and the reinforcing plate 56, and is made of, for example, PTFE (polytetrafluoroethylene). The peripheral edge of the insulating sheet 55 is rectangular so as to follow the connection region 33 of the frame body 31, and is provided on the connection region 33. The reinforcing plate 56 is configured to have the same shape as the insulating sheet 55 in a plan view, and a peripheral edge portion thereof is provided on the connection region 33. The reinforcing plate 56 is made of, for example, SUS (stainless steel), and the thinner plate 52 and the conductive plates 53, 54 are pressed and deformed by the thinner flowing through the dust collecting region 30, so that the thinner is in the dust collecting region. It has a role of preventing leakage from 30.

By the way, although the display is omitted in FIG. 4, through holes are formed in the insulating sheet 55 and the reinforcing plate 56 at positions corresponding to the through holes 34 of the frame body 31, and the through holes are formed, for example. A male screw 61 made of metal is inserted. For example, a female screw corresponding to the male screw 61 is formed on the inner circumference of the through hole of the reinforcing plate 56, and the two reinforcing plates 56 are fixed to the frame 31 by screwing these screws. Further, when the reinforcing plate 56 is fixed in this way, the seal member 51 is in a crushed state on one surface side and the other surface side of the frame body 31, and the electrode plate 52, the conductive plates 53, and 54 are subjected to the restoring force. And the insulating sheet 55 is pressed toward the reinforcing plate 56 that is crushing the sealing member 51. As a result, the seal member 51 is brought into close contact with the electrode plate 52 and the frame body 31, and the positions of the electrode plate 52, the conductive plates 53, 54 and the insulating sheet 55 are fixed.

When such fixing is performed, the positions of the electrode plate 52 and the conductive plate 53 are restricted by being surrounded by a step between the opening edge portion 32 of the frame body 31 and the connection region 33. Therefore, the position shift of the reinforcing plate 56 in the plane does not occur. Further, the conductive plates 53 and 54, the insulating sheet 55, and the reinforcing plate 56 are provided with through holes at positions corresponding to each other, and from the outside of the reinforcing plate 56 (the side opposite to the side facing the dust collecting region 30), By inserting a screw 62 made of a resin such as PEEK (polyetheretherketone) into these through holes, the conductive plates 53 and 54 and the insulating sheet 55 are displaced in the plane of the reinforcing plate 56. It is designed not to be. That is, the structure is such that the contact with the male screw 61 due to the misalignment of the electrode plate 52 and the conductive plates 53 and 54 and the accompanying energization of the male screw 61 do not occur.

Subsequently, the dimensions of each part of the dust collecting region 30 will be described. In FIG. 6, the length of the thinner in the dust collecting region 30 along the flow direction is L1, and in FIG. 5, the separation distance between the two electrode plates 52 (width of the dust collecting region 30) is shown as L2. With respect to the length L1 along the flow direction, the region where the electric field is formed along the flow direction of the thinner is increased so that the thinner can surely collect foreign matter during the flow in the dust collection region 30. The larger the value, the more preferable.

Further, the separation distance L2 between the two electrode plates 52 is preferably reduced within a range that does not interfere with the flow of thinner in order to increase the electric field in the dust collecting region 30. Further, as described above, the frame body 31 is made of resin and is more likely to be deteriorated than the silicon constituting the electrode plate 52. Therefore, the frame body is larger than the area where the two electrode plates 52 are in contact with the dust collecting region 30. It is preferable to reduce the area where 31 contacts the dust collecting region 30. From these viewpoints, it is preferable that the length L1 along the flow direction of thinner> the separation distance L2 between the two electrode plates 52.

Further, the height of the dust collecting region 30 along the direction orthogonal to the thinner flow direction in the dust collecting region 30 is shown as L3 in FIG. The larger the height L3, the larger the distance between the positions of the male screws 61 arranged along the thinner flow direction, that is, the position where the reinforcing plate 56 is fastened and the upper and lower center positions of the dust collecting region 30, and the reinforcing plate The stress received from the thinner on each part of 56, the electrode plate 52, the conductive plate 53, 54, etc. becomes large, and each of these members tends to bend.

In this way, from the viewpoint of ensuring the strength of each member, it is preferable to reduce the height L3, but as described above, it is necessary to make the separation distance L2 between the two electrode plates 52 relatively small. From the viewpoint of ensuring a sufficient flow rate of thinner flowing through the dust region 30, it is preferable to increase the height L3. For this reason, it is preferable to configure the dimensions so that L1> L3> L2. Specifically, L1 is, for example, 260 mm, L2 is, for example, 5 mm, and L3 is, for example, 80 mm.

As shown in FIG. 3, one end of an electric wire 63 made of a metal such as copper is connected to the connection portion 57 of each of the conductive plates 54 as in the conductive plate 54, and the other end of the electric wire 63 is connected to the DC power supply 64. It is connected. The DC power supply 64 applies a DC voltage to the electrode plate 52 via the electric wire 63 and the conductive plates 54 and 53. Further, the direction of the current supplied from the DC power supply 64 to the electrode plate 52 can be switched. Therefore, the polarity of each electrode plate 52 can be reversed.

Here, the reason why the electrode plate 52 and the DC power supply 64 are connected via the conductive plates 53 and 54 will be described with reference to FIG. 8 showing an electrically equivalent circuit of the electrostatic precipitator module 3. R _Si is the resistance due to the electrode plate 52, Rc is the resistance of the conductive path connecting the DC power supply 64 and the electrode plate 52, and R _lq is the resistance due to thinner. This R _Si can be expressed by the following equation 1. A in the formula is the distance (cm) from the connection point with the conductive path in the electrode plate 52 to the thinner in the collection region 30, that is, the length in the direction in which the current flows in the electrode plate 52. Reference numeral B is a contact area (cm ² ) between the electrode plate 52 and the conductive path.
R _Si (Ω) = Electrical resistivity of silicon constituting the electrode plate 52 ρ (Ω · cm) × (A / B) ... Equation 1

Since the electrode plate 52 overlaps and is laminated on the conductive plates 53 and 54 which are conductive paths as described above, the current flows in the thickness direction of the electrode plate 52, so that A in Equation 1 is It corresponds to the thickness of the electrode plate 52. Assuming that the thickness of the electrode plate 52 is 0.1 cm and the contact area between the electrode plate 52 and the conductive plate 53 is 100 cm ² , the A / B of the above formula 1 is (0.1 cm / 100 cm ^2). ). Further, for comparison, instead of providing the conductive plates 53 and 54 in the electrostatic precipitator module 3, the electrode plate 52 is pulled out to the outside of the frame 31 to provide a connecting portion corresponding to the connecting portion 57 of the conductive plate 54. , It is assumed that a configuration in which this connecting portion and the end portion of the electric wire 63 are connected is considered. In such a configuration, A is the length from this connection to the dust collecting region 30, and B is the cross-sectional area of the end of the electric wire 63. Assuming that the length from the connection portion to the dust collecting region 30 is 10 cm and the cross-sectional area of the end portion of the electric wire 63 is 0.1 cm ² , the A / B is (10 cm / 0.1 cm ² ), so that the conductive plate When 53 and 54 are provided, the resistance R _Si (Ω) of the electrode plate 52 is theoretically {(0.1 cm / 100 cm ² ) / (10 cm / 0.) As compared with the case where the conductive plates 53 and 54 are not provided. 1 cm ² )} = 1/10 ⁵

That is, by providing the conductive plates 53 and 54 as described above and connecting the DC power supply 64 and the electrode plate 52, R _Si becomes very small. When R _Si is reduced in this way, the contact resistance between the electrode plate 52 and the conductive plates 53 and 54 is reduced, and the voltage loss between the electrode plate 52 and the conductive plates 53 and 54 is reduced. .. The numerical values of 0.1 cm for the thickness of the electrode plate 52 and 100 cm ^{2 for} the contact area between the electrode plate 52 and the conductive plate 53 are exemplified for convenience in order to explain the effects of the conductive plates 53 and 54. The thickness of the electrode plate 52 and the contact area are not limited to these numerical values.

By reducing the resistance R _Si of the electrode plate 52 as described above, it is possible to increase the number of materials that can be selected as the electrode plate 52 while ensuring an electric field having sufficient strength to adsorb foreign matter in the dust collecting region 30. .. The electrode plate 52 can be made of a material that is conductive and does not contaminate the treatment liquid flowing through the dust collecting region 30 with metal. Specifically, as the material, in addition to Si (silicon), for example, a metal plate whose surface is gold-plated, glassy carbon, conductive glass, a conductive resin, or the like can be used. Further, as the silicon, for example, solar grade silicon can be used.

As shown in FIG. 2, the resist coating device 1 is provided with a control unit 10 composed of a computer, and the control unit 10 stores a program. Regarding this program, control signals are transmitted to each part of the resist coating device 1 to control the operation of each part, and pre-wet processing, resist film film forming processing, foreign matter removal processing in thinner, and collection of dust collected foreign matter are performed. A group of steps is set up so that the removal process from the dust region 30 is executed. Specifically, each operation such as opening / closing each valve V, applying a voltage from the DC power supply 64 to the electrode plate 52 and reversing the direction of the current, moving each nozzle, and rotating the wafer W by the spin chuck 11 Controlled by the program. This program is installed in the control unit 10 from a storage medium such as a hard disk, a compact disk, a magneto-optical disk, or a memory card.

Next, the operation of the resist coating device 1 will be described with reference to FIGS. 9 to 12 which schematically show the state of the electrode plate 52 and the state of the foreign matter P in the thinner. A direct current is supplied to the electrode plates 52 by the DC power supply 64 via the conductive plates 53 and 54, and one of the two electrode plates 52 becomes the positive electrode and the other becomes the negative electrode, and the dust collection region of the electrostatic dust collection module 3 A voltage is applied to the 30 thinners to form an electric current. The valves V1 and V2 of the thinner supply pipe 22 and the valves V3 of the waste liquid pipe 27 described with reference to FIG. 2 are closed.

Then, the wafer W is placed on the spin chuck 11 and rotates, and the thinner discharge nozzle 18 moves from the standby region outside the cup 14 onto the center of the wafer W. On the other hand, suction is performed by the pump 24, and the thinner stored in the thinner storage tank 21 passes through the intermediate tank 23 and heads for the pump 24. After that, the valves V1 and V2 of the thinner supply pipe 22 are opened, and the thinner is pumped to the downstream side by the pump 24. The pumped thinner flows into the dust collection region 30 of the electrostatic precipitator module 3 through the filter 25 (FIG. 9), and the positively charged foreign matter P contained in the thinner enters the electrode plate 52 which is the negative electrode. Foreign matter P having a negative charge is attracted by electrostatic force to the electrode plate 52 which is a positive electrode and is collected as dust (FIG. 10).

The thinner from which the foreign matter P is collected and removed in this way is directed from the dust collecting region 30 to the discharge nozzle 18, and is supplied from the discharge nozzle 18 to the central portion of the wafer W. This thinner spreads from the central portion to the peripheral portion of the wafer W by the centrifugal force of the rotation of the wafer W and is supplied to the entire surface of the wafer W to perform prewetting. After that, the pressure feeding of thinner by the pump 24 is stopped, the valves V1 and V2 are closed, and the supply of thinner to the wafer W is stopped. After that, the resist is supplied from the discharge nozzle 17 to the central portion of the pre-wet wafer W, spreads to the peripheral portion of the wafer W by the centrifugal force of rotation of the wafer W, and is supplied to the entire surface of the wafer W. Therefore, a resist film is formed on the entire surface of the wafer W.

For example, after the pre-wet and the resist film are formed on a predetermined number of wafers W, the polarities of the electrode plates 52 are reversed with the valves V1 and V2 closed. That is, of the two electrode plates 52, the other is the positive electrode and one is the negative electrode. As a result, the foreign matter P adsorbed on the electrode plate 52 repels the electrode plate 52 that has been adsorbed until then, and is released into the thinner of the dust collecting region 30 (FIG. 11). Subsequently, as in the case of supplying thinner to the nozzle 18, the thinner is pumped to the dust collecting region 30 by the pump 24 and the valve V3 is opened. As a result, the foreign matter P released from the electrode plate 52 is washed away from the dust collecting region 30 together with the thinner (FIG. 12), flows into the waste liquid portion 28, and is removed.

According to the electrostatic dust collecting module 3 constituting the resist coating device 1, the conductive plates 53 and 54 forming a conductive path provided so as to be laminated on the electrode plate 52 between the DC power supply 64 and the electrode plate 52. The contact resistance between the electrode plate 52 and the conductive plates 53 and 54 can be made relatively small. Thereby, the electric field in the dust collecting region 30 between the electrode plates 52 can be made strong enough to collect the foreign matter P, and the degree of freedom in selecting the material of the electrode plate 52 can be increased.

Further, the electrostatic precipitator module 3 is provided in the supply pipe 22 so as to remove foreign matter in the thinner each time the thinner flows to the discharge nozzle 18. Therefore, since foreign matter is removed from thinner having a relatively small volume, the number of electrodes provided can be reduced and the structure of the electrodes can be avoided as compared with the case where dust is collected in the storage tank 21, so that the module can be used. The manufacturing cost can be suppressed.

By the way, the frame is not limited to being configured to form the dust collecting region 30 having the above-mentioned shape. FIG. 13 shows a vertical sectional plan view of the frame body 71 forming the dust collecting region 30 having a shape different from that of the frame body 31. Hereinafter, the frame body 71 will be described focusing on the differences from the frame body 31. The upstream side (inflow port 35 side) of the dust collection region 30 of the frame body 71 is formed as two plan-view wedge-shaped flow paths that are gradually expanded from the two inflow ports 35 toward the downstream side (outflow port 37 side). It is configured. This wedge-shaped flow path is enlarged and shown in the circle of the chain line at the tip of the arrow of the chain line. By making the flow path wedge-shaped in this way, the rapid expansion of the flow path seen from the inflow port 35 is suppressed, and the formation of the above-mentioned eddy current in the vicinity of the inflow port 35 is prevented. In order to reliably prevent such a vortex, the smaller the angle of the tip of the wedge shown by θ1 in the figure, the more preferable, for example, 15 ° or less. These two wedge-shaped flow paths are expanded in the vertical direction in a plan view on the way toward the downstream side of the dust collection region 30, and merge with each other toward the downstream side.

Further, the frame body 71 also has symmetry in its shape vertically and horizontally as in the frame body 31. Therefore, the downstream side (outflow port 37 side) of the dust collection region 30 of the frame body 71 is configured as two plan-view wedge-shaped flow paths that are gradually reduced toward the two outflow ports 37. The two wedge-shaped channels are expanded in the vertical direction when viewed toward the upstream side, and merge with each other when viewed toward the upstream side. The reason why the flow path forming the dust collection region 30 is wedge-shaped even in the vicinity of the outflow port 37 is that a vortex is formed when the flow path is sharply narrowed as described above. This is to prevent it.

A spare DC power supply 72 different from the DC power supply 64 may be connected in parallel with the DC power supply 64 to the connection portion 57 of the two conductive plates 54. FIG. 14 shows the electrostatic precipitator module 3 to which the DC power supplies 64 and 72 are connected as an equivalent circuit in the same manner as in FIG. The direct current power supply 72 is composed of an uninterruptible power supply (UPS). For example, when there is no abnormality in the DC power supply 64, a current is supplied from the DC power supply 64 to the conductive plate 54, and no current is supplied from the DC power supply 72 to the conductive plate 54.

However, when a trouble such as a power failure occurs and the DC power supply 64 becomes unusable, a current is supplied from the DC power supply 72 to the conductive plate 54. As a result, it is possible to prevent the foreign matter P collected on the electrode plate 52 from being discharged to the thinner in the dust collecting region 30. Therefore, a power failure occurs in the resist coating device 1 during the processing by the resist coating device 1, and the foreign matter P remains adsorbed on the electrode plate 52 when the processing of the wafer W is restarted after the power failure is restored. Therefore, it is possible to prevent the foreign matter P from being supplied to the wafer W from the thinner discharge nozzle 18. The state of the power supply device that supplies power to each part of the resist coating device 1 may be monitored to monitor the presence or absence of a power failure, or an ammeter is provided on the electric wire 63 that connects the DC power supply 64 and the electrode plate 52. , The presence or absence of a power failure may be monitored by the detected value of this ammeter.

FIG. 15 shows an exploded perspective view of the electrostatic precipitator module 7, which is a modified example of the electrostatic precipitator module 3. Hereinafter, the differences between the electrostatic precipitator module 7 and the electrostatic precipitator module 3 will be mainly shown. Explain to. Unlike the above-mentioned frame body 31, the frame body 73 constituting the electrostatic precipitator module 7 does not have a step for partitioning the opening edge portion 32 and the connection area 33 on one side and the other side. Further, at one end and the other end in the flow path direction, the upper and lower central portions of the frame body 31 form projecting portions 74 and 75 protruding outward of the frame body 31 along the length direction, and the projecting portions Inflow ports 35 and outflow ports 37 are provided in 74 and 75, respectively. The protrusion 74 is enlarged and shown in the frame of the dotted line indicated by the dotted arrow. Note that the outflow port 37 is not shown in FIG. Further, in order to facilitate identification in the drawing, the seal member 51 is displayed in gray scale.

The electrostatic precipitator module 7 is not provided with the conductive plate 54, but is provided with only the conductive plate 53. The size of the conductive plate 53 in the length direction is longer than the size of the electrode plate 52 in the length direction, and when the conductive plate 53 is attached to the frame body 73, the end portion of the conductive plate 53 in the length direction. Is located outside the frame 31, so that the end of the electric wire 63 can be connected to the end. Even in this electrostatic precipitator module 7, each part is fixed by the female screw and the male screw 61 of the through hole of the reinforcing plate 56 being screwed together and the restoring force of the sealing member 51. In this example, the male screw 61 is the frame body 73. Is screwed on the outside of the frame body 73 without penetrating. As for the electrostatic precipitator module 7, various materials can be selected as the electrode plate 52 as in the electrostatic precipitator module 3.

Subsequently, the electrostatic precipitator module 8 configured to be applicable to the three resist coating devices 1 will be described with reference to the cross-sectional plan view of FIG. The electrostatic precipitator module 8 is provided with three frame bodies 73 arranged so that their openings overlap each other, and the three frame bodies 73 are shown as frame bodies 73A, 73B, and 73C in the order of arrangement. ing. Further, the dust collecting regions formed by these frame bodies 73A, 73B and 73C are shown as 30A, 30B and 30C. Further, in FIG. 17, the flow direction of thinner is indicated by an arrow.

On one side of the frame 73A (opposite to the frame 73C), an electrode plate 52, a conductive plate 53 (referred to as 53A for convenience), and an insulating sheet that form a dust collection region 30A like the electrostatic precipitator module 7. 55 and the reinforcing plate 56 are laminated in this order toward the side opposite to the frame body 73C. On the other surface side of the frame 73A, an electrode plate 52 forming a dust collecting region 30A toward the frame 73B, a conductive plate 53 (referred to as 53B for convenience), and an electrode plate 52 forming a dust collecting region 30B are formed therein. They are stacked and provided in order. On the other side of the frame 73B, an electrode plate 52 forming a dust collecting region 30B, a conductive plate 53 (referred to as 53C for convenience), and an electrode plate 52 forming a dust collecting region 30C are located on the other surface side of the frame 73B toward the frame 73C. They are stacked and provided in order. On the other side of the frame body 73C, an electrode plate 52, a conductive plate 53 (referred to as 53D for convenience), an insulating sheet 55, and a reinforcing plate 56 forming a dust collecting region 30C are formed toward the opposite side of the frame body 73B. They are stacked and provided in this order. The conductive plates 53A and 53C are connected in parallel to the positive terminal of the DC power supply 64 via the electric wire 63, and the conductive plates 53B and 53D are connected in parallel to the negative terminal of the DC power supply 64 via the electric wire 63. Has been done.

As described above, in the electrostatic precipitator module 8, the two reinforcing plates 56 and the two insulating sheets 55 are shared in the three dust collecting regions 30. Further, the conductive plate 53B is shared with respect to the dust collection area 30A (first supply path) and the dust collection area 30B (second supply path), and the conductive plate 53C is shared with the dust collection areas 30B and 30C. Has been done. Therefore, there is an advantage that the space occupied by the module in the device can be reduced by providing the electrostatic precipitator module 8 having a reduced number of components, as compared with the provision of the three electrostatic precipitators 3 described above.

By the way, according to the verification by the present inventor, it has been confirmed that a large amount of foreign matter P is contained in the liquid passing through the dust collection region 30 immediately after the start of use of the electrostatic precipitator module 3. This is because foreign matter is attached to the electrode plate 52 in the manufacturing process for forming the electrode plate 52, and among the foreign matters attached to the electrode plate 52, the foreign matter having a positive charge is positively electrodeed by the electrode plate 52 to which the foreign matter is attached. It is considered that the foreign matter having a negative charge is discharged to the dust collecting region 30 when the foreign matter becomes a negative electrode plate to which the foreign matter is attached becomes a negative electrode. Therefore, after the electrode plate 52 is manufactured and before it is used, a DC voltage or an AC voltage is applied to the electrode plate 52 to release the adhering foreign matter. That is, the electrode plate 52 is aged. After performing this aging for an appropriate time, the electrostatic precipitator module 3 to which the electrode plate 52 is attached is used to collect the dust of foreign matter as described above. As a result, it is possible to prevent thinner containing foreign matter from being supplied to the thinner discharge nozzle 18.

When the electrode plate 52 is made of silicon as described above, SC1 (mixed solution of ammonia water, hydrogen peroxide and water) and DHF (mixed solution of hydrofluoric acid and water) used as a cleaning solution for a silicon wafer. , SC2 (mixed solution of hydrochloric acid, hydrogen peroxide and water), SPM (mixed solution of sulfuric acid, hydrogen peroxide and water), SPS (mixed solution of sulfuric acid and hydrogen peroxide), etc. It is also effective to remove foreign matter adhering to the electrode plate 52 before using the electrode plate 52. One of such cleaning treatment and the above-mentioned aging may be performed, or both may be performed.

The electrostatic precipitator module 3 may be provided on the upstream side and the downstream side of the thinner supply pipe 22, respectively, so that foreign matter can be collected more reliably. That is, a plurality of electrostatic precipitators 3 may be provided in the thinner supply pipe 22. Further, the position where the electrostatic precipitator module 3 is provided is not limited to the position shown in FIG. 2, and may be provided on the upstream side of the filter 25. However, in such an arrangement, a large amount of foreign matter adheres to the electrode plate 52 in one pre-wet treatment. When the amount of foreign matter adhering to the electrode plate 52 increases, the adsorption force for the foreign matter flowing through the dust collecting region 30 together with the thinner decreases, so that the frequency of removing the foreign matter P from the electrode plate 52 described with reference to FIGS. 11 and 12 is performed. Will be higher. That is, since the processing of the wafer W is interrupted more frequently, it is preferable to provide the electrostatic precipitator module 3 on the downstream side of the filter 25 as shown in FIG. As shown in FIG. 2, the filter 25 and the electrostatic precipitator module 3 are provided in this order toward the downstream side of the supply pipe 22, and the filter 25 is further provided on the downstream side of the electrostatic precipitator module 3. May be good.

The electrode for forming the dust collecting region 30 may be provided with a planar body facing the dust collecting region 30, and is not limited to a plate shape. The schematic cross-sectional plan view of FIG. 18 shows an example of an electrostatic precipitator module 3 in which a dust collecting region 30 is formed by a block-shaped electrode 76 having a relatively large thickness instead of the electrode plate 52. The conductive plates 53 and 54 can also be changed to a block-shaped conductor such as the electrode 76. Further, as shown in FIG. 19, the two rod-shaped bodies 77 formed along the two sides in the length direction of the elongated electrode plate 52 have the peripheral edge portion of the electrode plate 52 and the peripheral edges of the conductive plates 53 and 54. A portion may be attached to form a dust collecting region 30. In this case, one end and the other end of the space between the two rod-shaped bodies 77 become the inflow port 35 and the outflow port 37. As described above, the support member that supports the two electrodes facing each other is not limited to the frame body.

Further, the inflow port 35 and the outflow port 37 are not limited to being provided in the frame body 31, that is, being provided between the two electrode plates 52. In FIG. 20, in the electrostatic precipitator module 3, the inflow port 35 and the outflow port 37 penetrate the electrode plates 52, the conductive plates 53, and 54 provided on one surface side of the frame 31, and face the dust collection region 30. An example of forming as a hole is shown. When the ports 35 and 37 are formed in this way, the insulating sheet 55 and the reinforcing plate 56 on one side of the frame 31 are also reinforced by providing through holes at positions corresponding to the inflow port 35 and the outflow port 37. The treatment liquid can be supplied to the dust collecting region 30 and discharged from the outside of the plate 56.

By the way, in the above-mentioned electrostatic precipitator module 3, the conductive plate 53 is configured to have the same size as the electrode plate 52 when viewed in a plane, and the region where the conductive plate 53 and the electrode plate 52 overlap (hereinafter, referred to as an overlapping region). Is configured to be equal to the area of the electrode plate 52 viewed in a plane (hereinafter, simply referred to as the area of the electrode plate 52), but as shown in FIG. 21, the area of the overlapping region is the electrode plate 52. The conductive plate 53 may be formed so as to be smaller than the area of. As the area of the overlapping region becomes larger than the area of the electrode plate 52, it is not necessary for the current to flow in the electrode plate 52 in the in-plane direction, and the current flows through the electrode plate 52 in the thickness direction. That is, in the electrode plate 52 described by the above-mentioned equation 1, the length in the direction in which the current flows is shortened. Therefore, the resistance in the electrode plate 52 becomes small. Therefore, it is preferable that the ratio of the area of the overlapping region to the area of the electrode plate 52 on one surface side and the other surface side of the frame body 31, for example, 70% or more.

Further, the present invention is not limited to being used only for thinner as a treatment liquid, but is preferably used for a material in which ionization is unlikely to occur in the collection region 30. In addition to thinner, it is preferable to use, for example, a developer composed of an organic solvent for developing a negative resist, or a cleaning solution composed of pure water for cleaning the wafer W after development, as a treatment solution. .. In addition, each of the above-mentioned configuration examples can be combined or changed as appropriate. Specifically, for example, the dust collecting region 30 of the frame body 73 of FIG. 15 may be configured to include a wedge-shaped flow path as shown in FIG.

(Evaluation test)
The evaluation test 1 conducted in connection with the present invention will be described. As the evaluation test 1-1, the wafer W made of silicon was aged by applying a DC voltage of 100 V for 1 hour. Then, the degree of adhesion of foreign matter having a diameter of 20 nm or more was examined on the surface of the wafer W. The result is a photograph of FIG. 22, and in the photograph, the foreign matter is shown by dots brighter than the region where the foreign matter is not attached. As shown in this photograph, in the evaluation test 1-1, a large amount of foreign matter remained on the surface of the wafer W. As the evaluation test 1-2, after aging in the same manner as in the evaluation test 1-1, the surface of the wafer W was washed with the above SC1, and then the degree of adhesion of foreign matter having a diameter of 20 nm or more was examined. The result is a photograph shown in FIG. There were very few foreign substances adhering in this way. Therefore, it can be seen that it is effective to clean the electrode plate 52 with the above-mentioned cleaning liquid and then use the electrode plate 52 in order to prevent foreign matter from adhering to the wafer W to be pre-wet-treated.

1 Resist coating device 10 Control unit 18 Thinner discharge nozzle 2 Thinner supply mechanism 21 Thinner storage tank 30 Dust collection area 31 Frame body 52 Electrode plate 53, 54 Conductive plate 64 DC power supply

Claims (4)

The source of the treatment liquid and
The mounting part on which the board is mounted and
A nozzle for processing the substrate by supplying the treatment liquid supplied through the treatment liquid supply path from the supply source to the substrate mounted on the above-described mounting portion.
The first electrode and the second electrode, which are opposed to each other and are each composed of a planar body and form a flow path forming a part of the processing liquid supply path between them,
An insulating support member that partitions the flow path together with the first electrode and the second electrode and is interposed between the peripheral edges of the first electrode and the second electrode.
An inflow port and an outflow port for the treatment liquid provided on the support member so as to face the flow path,
A first planar surface that is laminated in contact with the outer surface of the first electrode, is of a material different from that of the first electrode, connects the power supply unit and the first electrode, and forms a first conductive path. With the body
It is laminated in contact with the outer surface of the second electrode, is made of a material different from that of the second electrode, forms a second conductive path connecting the power supply unit and the second electrode, and has an electric field in the flow path. With a second planar body for forming
A processing liquid supply device including. The first electrode and the second electrode, the silicon surface is gold-plated metal plate, glassy carbon, the process liquid supply apparatus according to claim 1, wherein a conductive glass or conductive resin. The treatment liquid supply device according to claim 1 or 2 , wherein the treatment liquid is any one of a cleaning liquid for the substrate containing an organic solvent, a developing liquid, and pure water. A filter for filtering and removing foreign matter is provided in the treatment liquid supply path.
The treatment liquid supply device according to any one of claims 1 to 3 , wherein the first electrode and the second electrode are provided on the downstream side of the filter.

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