Liquid processing apparatus, liquid processing method, and storage medium

A solvent such as PGMEA is coated on a wafer in advance to easily spread resist liquid onto the wafer on a spin chuck. Before coating, the solvent supplied from a solvent supply source is stored in a distill tank first, the solvent is heated by a heating unit to be evaporated, and the evaporated solvent is cooled by a cooler, thereby performing the purification of the solvent by distillation. Therefore, particles among the solvent are removed. The purified solvent is stored in a storage tank first, and then supplied to a solvent nozzle above the spin chuck from a solvent supplying line. And then, the solvent is coated on the wafer by ejecting the solvent from the solvent nozzle to the wafer. Further, the distill tank is cleaned periodically to suppress the increase of the concentration of the particles in the solvent.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority from Japanese Patent Application No. 2012-013136, filed on Jan. 25, 2012, with the Japanese Patent Office, the disclosure of which is incorporated herein in its entirety by reference.

TECHNICAL FIELD

The present disclosure relates to a liquid processing apparatus that supplies a processing liquid to be coated on a surface of a wafer in manufacture of, for example, a semiconductor wafer.

BACKGROUND

In a photolithography process of manufacturing processes of a semiconductor device, a resist coating processing is performed to form a resist film on the surface of a semiconductor wafer (“wafer”). In general, a spin coating method is adopted as the coating processing. As illustrated inFIG. 9, the spin coating method is a method in which a resist liquid is supplied to a center portion of a wafer W from a nozzle11in a state where wafer W is fixed on a spin chuck10and is rotated in a high speed to spread the resist liquid toward the outside in a diameter direction of wafer W by centrifugal force, thereby coating the resist liquid.

When the resist liquid is coated, it is necessary to coat the resist liquid on wafer W with high in-plane uniformity. Since most of the resist liquid on wafer W is thrown out of the wafer and wasted in the spin coating method, what is required is a method to reduce the amount of the resist liquid supplied onto wafer W.

As a method to save resist, so-called a pre-wet method is known in which a processing liquid to modify a surface of a substrate is coated on a surface of the wafer prior to coating a resist liquid such that the surface of the wafer becomes wet with a solvent thereby facilitating the spread of the resist liquid (see, e.g., Japanese Patent Application Laid-Open Nos. H07-320999 and 2007-299941). When the solvent is coated, a filter with a mesh body is disposed on a flow line from a processing liquid bottle to a solvent nozzle such that foreign matter in of the solvent is filtered in the filter.

Meanwhile, as circuit patterns are being miniaturized, the presence of the foreign matter with an infinitesimal size, which has not been practically a problem until now, is expected to affect the yield. For example, foreign matter (particles) may involve foreign matter derived from a crude liquid of the processing liquid, foreign matter derived from a transporting path which is mixed while the processing liquid is passing through an apparatus from a crude liquid tank, or ionized metal. Various designs have been executed to remove the foreign matter from the processing liquid. However, there is a limit in miniaturizing meshes of filters and it is difficult to remove an ion by an existing filter.

SUMMARY

The present disclosure provides a liquid processing apparatus including: a substrate holding unit configured to hold a substrate horizontally; a processing liquid nozzle configured to perform a liquid processing with respect to the substrate horizontally held by the substrate holding unit by supplying a processing liquid from a processing liquid supply source; an evaporating unit configured to evaporate the processing liquid supplied from the processing liquid supply source to obtain vapor; a cooling unit configured to cool and liquefy the vapor of the processing liquid obtained from the evaporating unit; a storage tank configured to store the processing liquid obtained by the cooling of the cooling unit; and a liquid sending mechanism configured to send the processing liquid within the storage tank to the processing liquid nozzle.

DETAILED DESCRIPTION

The present disclosure has been made in an effort to provide a technology in which the entry of foreign matter from the processing liquid on the substrate is suppressed when the substrate is processed by the processing liquid.

A liquid processing apparatus of the present disclosure includes: a substrate holding unit configured to hold a substrate horizontally; a processing liquid nozzle configured to perform a liquid processing with respect to the substrate horizontally held by the substrate holding unit by supplying a processing liquid from a processing liquid supply source; an evaporating unit configured to evaporate the processing liquid supplied from the processing liquid supply source to obtain vapor; a cooling unit configured to cool and liquefy the vapor of the processing liquid obtained from the evaporating unit; a storage tank configured to store the processing liquid obtained by the cooling of the cooling unit; and a liquid sending mechanism configured to send the processing liquid within the storage tank to the processing liquid nozzle.

The above-described liquid processing apparatus further includes a resist nozzle configured to supply resist liquid with respect to the substrate held by the substrate holding unit. The processing liquid is a solvent that is ejected to the substrate before supplying the resist liquid to the substrate.

In the above-described liquid processing apparatus, the evaporating unit includes a distill tank configured to distill the processing liquid, and a heating unit configured to heat the processing liquid stored within the distill tank.

The above-described liquid processing apparatus further includes a filter unit installed in a flow line between the processing liquid supply source and the distill tank and configured to remove foreign matter.

The above-described liquid processing apparatus further includes: a gas introducing unit configured to introduce carrier gas into the distill tank, and a gas discharging unit configured to discharge the carrier gas within the storage tank.

The above-described liquid processing apparatus further includes a depressurizing exhaust line to depressurize the vapor atmosphere within the storage tank.

A liquid processing method of the present disclosure includes: obtaining vapor by evaporating a processing liquid supplied from a processing liquid supply source by an evaporating unit; obtaining a processing liquid by cooling and liquefying the vapor by a cooling unit installed in a flow line between the evaporating unit and a storage tank; storing the processing liquid obtained by the cooling of the cooling unit in the storage tank; and performing a liquid processing by supplying the processing liquid within the storage tank through a processing liquid nozzle to a substrate horizontally held by a substrate holding unit.

In the above-described liquid processing method, the processing liquid is a solvent, and a resist liquid is supplied to the substrate from a resist nozzle after performing the liquid processing.

In the above-described liquid processing method, the vapor obtaining step includes: storing the processing liquid in a distill tank and heating the processing liquid stored within the distill tank.

The above-described liquid processing method further includes passing the processing liquid through a filter unit installed in a flow line between the processing liquid supply source and the evaporating unit prior to evaporating the processing liquid of the processing liquid supply source.

The present disclosure also provides a non-transitory computer-readable storage medium storing a computer program that, when executed, causes a computer to perform the above-described liquid processing method.

According to the present disclosure, the processing liquid supplied from the processing liquid supply source is evaporated by the evaporating unit to obtain vapor, a processing liquid obtained by cooling and liquefying the vapor is supplied from the nozzle to the substrate, thereby performing the liquid processing. Accordingly, the foreign matter (for example, particles or ionized metals) among the processing liquid may be reduced. As a result, the entry of the foreign matter from the processing liquid on the substrate is suppressed, which is extremely effective for the semiconductor device manufacturing technology in which, for example, the minuteness of a circuit pattern proceeds.

Hereinafter, a first exemplary embodiment will be described in which a liquid processing apparatus of the present disclosure is applied to a resist coating apparatus.

First, the entire configuration of a resist coating apparatus will be described briefly. As illustrated inFIG. 1, the resist coating apparatus includes: a cup module including a spin chuck20configured to hold a wafer W, which is a substrate, horizontally, and a cup body23; a solvent nozzle40configured to supply a solvent to wafer W; and a resist nozzle30configured to supply a resist liquid to wafer W. The cup module is configured to receive and discharge, for example, the solvent scattered from wafer W from a drain line26ain the bottom side, and to exhaust gas from an exhaust line25ain the bottom side, thereby preventing mist from being scattered to the processing atmosphere.

Solvent nozzle40is connected to a solvent supply source42via a solvent supplying line41, and a solvent supplying device4is installed on the way of solvent supplying line41. Resist nozzle30is connected to a resist supply source32via a resist supplying line31, and a resist supplying device33is installed on the way of resist supplying line31.

Solvent supplying device4and resist supplying device33include a supply control mechanism group including, for example, a valve, a filter, and a pump. Hereinafter, solvent supplying device4will be described in detail.

As illustrated inFIG. 2, solvent supplying device4includes a distill tank51, and a solvent supplying port45is formed in the top of distill tank51. One end of a pipe42ais connected to solvent supplying port45, and other end is connected to solvent supply source42. A filter43and a valve44are interposed in pipe42a. A heating unit53to heat the solvent in distill tank51is installed in the bottom side of distill tank51. Therefore, the solvent may be heated up to a constant temperature equal to or higher than the boiling point of the solvent. Distill tank51is provided with a high-level (H) sensor52ato detect a liquid surface at a high-level and a low-level (L) sensor52bto detect a liquid surface at a low-level.

The bottom portion within distill tank51is curved, and the center portion thereof is provided with a drain line54to discharge the solvent. The control of the discharge of the solvent via drain line54is performed by opening/closing a drain valve55, and the solvent is discharged through a flow rate meter56. Distill tank51is provided with a carrier gas introducing port83at the top thereof to introduce carrier gas into distill tank51. The carrier gas is supplied from a carrier gas supply source81into distill tank51through a gas valve82. In the present exemplary embodiment, distill tank51, heating unit53, and carrier gas introducing port83constitute an evaporating unit to evaporate the solvent.

To the center of the top of distill tank51, a lower end of a recovery pipe61is connected to recover the evaporated solvent. Recovery pipe61extends vertically upright, and the top end thereof is bent with an acute angle to extend downward obliquely in a spirally shaped state. The spirally shaped pipe portion corresponds to an inner pipe of a cooler60, and the inner pipe is accommodated in an outer pipe60aof which both top and bottom surfaces are curved. The bottom portion of outer pipe60ais installed with an injecting port64to inject cooling water as a cooling liquid into the outer pipe, the top portion of outer pipe60ais installed with a discharging port63to discharge the cooling water. That is, the vapor of a chemical liquid recovered by recovery pipe61enters to inner pipe62, and is liquefied as inner tube62is water-cooled within cooler60. In this manner, the solvent within distill tank51is purified.

The solvent purified in cooler60is recovered to a storage tank71from a solvent recovery port65formed on the top of storage tank71via a recovery pipe73that extends from the lower end of inner pipe62. The inside of storage tank71is provided with a high-level (H) sensor72ato detect a liquid surface at a high-level, a low-level (L) sensor72bto detect a liquid surface at a low-level, and a ultra low-level (LL) sensor72cto detect a liquid surface at a ultra low-level. The bottom portion within storage tank71is curved, and a solvent supplying line74is connected to the center of the bottom portion to supply solvent to wafer W through solvent nozzle40. The storage tank71is provided with a carrier gas discharging port84at the top thereof to discharge the carrier gas to the outside through a gas valve85.

Solvent supplying line74is provided with a liquid send pump75, a discharging valve76, and a flow rate meter77which constitute a liquid sending mechanism, and solvent nozzle40is connected to the front end of the solvent supplying line74.

Here, a solvent for pre-wetting which is capable of being processed in the present resist coating apparatus may be, for example, PGMEA, PGME, cyclohexanone, γ-butyl lactone, butyl acetate, or MAK (2-heptanone). An available carrier gas may be, for example, N2gas or helium.

The resist coating apparatus is configured to be controlled by a control unit100, as illustrated inFIG. 1. Control unit100includes, for example, a computer, and is provided with a program, a memory and a CPU. Commands (respective steps) are stored in the program such that a control signal is transmitted from control unit100to execute the operations as described below, thereby performing a predetermined solvent processing. The program is stored in a computer-readable storage medium, for example, a recording unit such as, for example, a flexible disc, a compact disc, a hard disc, and a MO (a magneto-optical disc) and is installed in control unit100. Here, the program installed in control unit100includes a program that controls, for example, spin chuck20, resist nozzle30, resist supply source32, resist supplying device33, solvent nozzle40, solvent supply source42, valve44, heating unit53, H sensor52a, L sensor52b, drain valve55, flow rate meter56, cooler60, H sensor72a, L sensor72b, LL sensor72c, liquid send pump75, discharging valve76, flow rate meter77, carrier gas supply source81, gas valve82, and gas valve85such that each of these components may be controlled based on a program recipe stored in the memory of control unit100in advance.

Next, the operations of the above-mentioned exemplary embodiment will be described. First, the solvent for pre-wetting processing is supplied from solvent supply source42to solvent supplying device4through solvent supplying line41. InFIG. 2, the solvent such as, for example, PGMEA supplied to solvent supplying device4from solvent supply source42is filtered with a filer43for a rough filtration. In this way, particles of which sizes are equal to or more than the mesh of the filter are removed. The filtered solvent is supplied into distill tank51through valve44and solvent supplying port45.

The solvent supplied into distill tank51is heated by heating unit53to be evaporated. Here, the temperature of heating unit53is set to a temperature higher than, for example, the boiling point of PGMEA, for example, 160. The evaporated solvent is sent to recovery pipe61using N2gas as a carrier gas, in which the N2gas is supplied into distill tank51from carrier gas supply source81.

When the solvent is evaporated as described above, the storage of the solvent within distill tank51is performed at the same time. In addition, control is performed in such a manner that when the liquid surface arrives at a level higher than H sensor52a, the supply of the solvent from solvent supply source42is stopped by, for example, closing valve44and when the liquid surface arrives at a level lower than L sensor52b, the supply of the solvent from solvent supply source42is continued again. The solvent is continuously supplied from solvent supply source42when the liquid surface is positioned between H sensor52aand L sensor52b. As described above, the liquid surface of the solvent within distill tank51is normally maintained between H sensor52aand L sensor52b, thereby preventing the heating of empty distill tank51or the oversupplying of the solvent.

Meanwhile, the solvent vapor sent along with N2gas to recovery pipe61enters to inner pipe62of cooler60, and is water-cooled by the cooling water. Then, the solvent vapor is liquefied and dropped to the bottom side of inner pipe62. As described above, particles are removed from the solvent refined by the distillation. The purified and dropped solvent is recovered to storage tank71through recovery pipe73. N2gas including a non-liquefied solvent component flows through storage tank71, and then, is discharged to the outside from carrier gas discharging port84through gas valve85.

Here, when the liquid surface arrives at a level higher than H sensor72a, the supply of N2gas from carrier gas supply source81is stopped, heating unit53is deactivated, and the purification of the solvent is stopped. When the liquid surface arrives at a level lower than L sensor72b, the supply of N2gas from carrier gas supply source81is continued again, heating unit53is activated, and the purification of the solvent is continued again. When the liquid surface is positioned between H sensor72aand L sensor72b, the supply of N2gas and the operation of heating unit53are continued, and thus, the solvent is continuously refined. In this way, the liquid surface of the refined solvent within storage tank71is normally maintained between H sensor72aand L sensor72b.

When the supply amount of solvent purified by distillation to storage tank71is smaller than the amount of the solvent ejected to wafer W and the liquid surface becomes lower than LL sensor72c, the supply of the solvent to solvent nozzle40is stopped. In this way, the shortage of the amount of the solvent to be ejected to wafer W is prevented in advance.

When the purified solvent is stored in storage tank71with an amount sufficient for continuous processing of wafers, the process proceeds to a step of coating purified solvent to wafer W.

Meanwhile, wafer W is transferred onto spin chuck20from a transporting mechanism (not illustrated) in the outside of the resist coating apparatus, then is adsorbed and held by spin chuck20. Then, solvent nozzle40is moved above the center portion of wafer W, and the solvent is supplied in a controlled manner such that a suitable amount of the solvent is ejected to solvent nozzle40from solvent supplying device4.

After the solvent is ejected from solvent nozzle40onto wafer W, rotation driving unit21is controlled to increase the number of revolutions of wafer W, and thus, the solvent is diffused toward the outside by centrifugal force. Accordingly, a process for wetting the entire surface of wafer W by the solvent, that is, pre-wetting is performed. Also, the solvent may be supplied in a state where wafer W is being rotated. After the pre-wetting is completed, solvent nozzle40is retracted from the upper side of the center portion of wafer W, and resist nozzle30is moved to the upper side of the center portion of wafer W instead. The ejection of the resist liquid from resist nozzle30is initiated, and the number of revolutions of wafer W is controlled using, for example, a method disclosed in Japanese Patent Application Laid-Open No. 2007-299941, so that the resist liquid is diffused on wafer W. Since the pre-wetting processing has already been performed for wafer W, the resist liquid is steadily and smoothly diffused and spread in a stripe shape. Therefore, uneven coating is hardly caused.

However, as the above-described solvent supplying device4is continuously operated, the concentration of the particles in the solvent stored in distill tank51will be increased. For that reason, the present resist coating apparatus provides a cycle to refresh the inside of distill tank51by periodically wasting the solvent in the inside of distill tank51from drain line54of the bottom portion of distill tank51.

An example of the cycle, a timing to open drain valve55is determined based on the total count number of processed wafers or integrated flow rate of the solvent, a length of time required for fully discharging the solvent is calculated based on the amount of the solvent within distill tank51at the timing, valve44is closed, the supply of the solvent from solvent supply source42is stopped, and then, drain valve55is opened for the calculated length of time to drain the solvent. After the drain is completed, distill tank51may be cleaned by a cleaning liquid. As cleaning methods, a cleaning by the solvent (that is, a common cleaning) and a cleaning by acid to remove metallic ions attached on the inner wall of distill tank51may be considered. After draining or after cleaning (in case of using an acid, after a common cleaning by the solvent after the cleaning by the acid), drain valve55is closed again, and the supply of the solvent from solvent supply source42to distill tank51is continued again. Further, in the cleaning cycle, when the sufficient liquid amount exists in storage tank71, the cleaning cycle within distill tank51and the supply of the purified solvent from storage tank71to wafer W may be performed at the same time.

According to the exemplary embodiment, in the resist coating processing which is a liquid processing, since the pre-wetting solvent for wetting the surface of wafer W in advance is distilled by the distill tank and the processing liquid obtained thereby is supplied to the substrate from the nozzle to perform the liquid processing, foreign matter (for example, particles or ionized metal) in the processing liquid is reduced. As a result, the entry of the foreign matter to the substrate from the processing liquid is suppressed, which suppresses the decrease of a yield in manufacturing, for example, semiconductor devices, of which the circuit patterns are being miniaturized.

The purified solvent is secured in a dedicated tank by an amount required for a processing after the distillation. As a result, since the refined solvent may be steadily supplied to surfaces of wafers, the surfaces of the wafers may be continuously processed by the solvent containing a suppressed amount of particles in a pre-wetting processing.

MODIFIED EXAMPLES OF PROCESSING LIQUID SUPPLYING DEVICE

Next, modified examples of solvent supplying device4in the liquid processing apparatus of the first exemplary embodiment will be described. Further, the parts corresponding to those of the above-described exemplary embodiment will be denoted by the same reference numerals, and the descriptions thereof will be omitted.

Modified Example 1

In the example as illustrated inFIG. 3, liquid send pump75that was used in the above-described exemplary embodiment is omitted. When the solvent is not supplied to wafer W, after discharging valve76is closed, the carrier gas is supplied from carrier gas supply source81through recovery pipe61, inner pipe62of cooler60and recovery pipe73, and is discharged to the outside of storage tank71through gas valve85. When the solvent is ejected to wafer W, after gas valve85is closed, discharging valve76is opened, and the solvent is ejected to wafer W from solvent nozzle40from simultaneously with discharging the carrier gas.

That is, this example is a configuration where a carrier gas supplying mechanism is used instead of the pump as a liquid sending mechanism that sends the solvent to nozzle40, and the discharging pressure of the carrier gas is used to send the solvent at discharging valve76.

Modified Example 2

In the example as illustrated inFIG. 4, a depressurizing pump86which is a depressurizing mechanism (suction mechanism) is connected to storage tank71through gas valve85, in place of a suction/exhaust device for the carrier gas. Distill tank51and storage tank71are configured as a vacuum insulation tank. At the time of distilling, after valve44is closed to form the vapor phase space as a closed system, depressurizing pump86is driven and the solvent of distill tank51is heated by heating unit53. At that time, since the pressure within the system is lowered, the boiling point of the solvent is also lowered. When the solvent is ejected to wafer W, the solvent is controlled by liquid send pump75and discharging valve76.

In this modified example, since the boiling point of the solvent is lowered, the output of heating unit53that heats the solvent may be decreased. Accordingly, it can be expected that a yield may be improved in addition to enabling energy saving.

Modified Example 3

In the example as illustrated inFIG. 5, a circulation pump87is connected between gas valve82and gas valve85, in place of the suction/exhaust device for the carrier gas. At the time of distilling, valve44and discharging valve76are closed. Therefore, a circulation system is formed where the inner air is circulated from distill tank51through cooler60, and to storage tank71, gas valve85, circulation pump87, gas valve82, and distill tank51. When the solvent is ejected to wafer W, discharging valve76is turned to the opened state and liquid send pump75is driven.

In the modified example, since the solvent vapor not liquefied in cooler60may be returned to distill tank51again, the recovery efficiency of the refined solvent is increased.

Modified Example 4

In the example as illustrated inFIG. 6, a mesh type or porous filter91formed as a size suitable for the transverse cross-section of distill tank51is installed in a vapor phase area within distill tank51. When liquid surface becomes unstable due to, for example, bumping of solvent, a liquid lump containing particles or solvent mist is prevented from being mixedly introduced into recovery pipe61by filter91. A single filter91may be used, but a plurality of filters may be used in combination. As a material of the filter, for example, a fluorinated carbon resin (product name: Teflon (registered trademark)) may be used.

Filter91may be combined with the above-described exemplary embodiment or each of the modified examples.

Modified Example 5

In the example as illustrated inFIG. 7, a vaporizer57is used as the evaporating unit, instead of using distill tank51.

Vaporizer57includes a flat cylindrical housing, a volatizing member92installed in a transverse direction within the housing, and a heating unit53that heats volatizing member92. To the top of the housing, the upstream end of recovery pipe61is connected, and the carrier gas supplying line is also connected through carrier gas introducing port83. The surface of volatizing member92is formed as a volatizing surface of the solvent, and, for example, is configured such that an outlet of the downstream end of pipe42is connected to the center portion of the volatizing surface and the solvent is supplied to the volatizing surface from the outlet.

An example of the volatizing surface may be a structure configured such a plurality of elongated recesses are formed to extend radially from the center portion and the solvent from the outlet is spread to the entire volatizing surface by capillary phenomenon. For example, a porous structure may be used as volatile member92, and the outlet may be opened within the porous structure, so that the solvent from the outflow port may be absorbed into the porous structure, and volatilized from the top surface of the porous structure (volatizing surface).

In this example, the solvent maintained in volatizing member92is heated by heating unit53, and the solvent vapor is sent to recovery pipe61along with the carrier gas. Although the carrier gas within the system is flown by the carrier gas mechanism in this example, the pressure within the system may be controlled using the gas control mechanism by the vacuum suction of modified example 2.

Since the solvent is supplied to volatizing member92and continuously evaporated, vaporizer57has no liquid layer when viewed macroscopically. As a result, the mixed introduction of liquid lump or solvent mist to recovery pipe61is prevented.

Modified Example 6

In the example as illustrated inFIG. 8, a first storage tank71aand a second storage tank71bare installed as storage tank71. A liquid level sensor mechanism and a carrier gas discharging mechanism installed in each of the tanks are the same as those provided in storage tank71in the above-described exemplary embodiment. The purified solvent recovered from recovery pipe73is distributed to storage tanks71a,71bfrom solvent recovery ports65a,65bthrough a flow rate meter66based on a situation of, for example, the storage amount of the tank. Valves79a,79bare provided in the discharging ports for the purified solvent from tanks71a,71b, respectively, thereby controlling discharge of the solvent. Storage tanks71a,71bcooperate based on the situation of, for example, the storage amount of the tank to perform the storage of the refined solvent and the supply of the solvent to wafer W.

Three or more storage tanks may be used. Since the plural storage tanks are used, the discharge of the purified solvent may be continued stably.

In the solvent supplying device as described above, the solvent is filtered with filter43attached to the outside. Even though filter43is a filter accommodated in the pipe, the same configuration of the apparatus is possible. In addition, filter43is not always necessarily required.

Although cooler60as described above has is configured such that inner pipe62is water-cooled in the inside of outer pipe60ato perform distillation, it is not limited thereto if cooler60is configured such that solvent vapor is distilled by cooling and purified solvent obtained thereby is recovered to storage tank71. For example, a Peltier element may be provided in the cooling unit, the both ends of the inner pipe may be installed in the top portion, and the body of the inner pipe may be cooled by a flask type cooling mechanism.

Further, it may be also considered that a temperature sensor is installed in distill tank51, the temperature of the liquid within distill tank51, which is detected by a sensor unit, always be monitored, and the output of heating unit53is controlled based on the monitored temperature of the liquid to control the temperature of the liquid in real time. In this case, distill tank51may be prevented from being overheated even in a case where, for example, the liquid surface within distill tank51is extremely lowered.

Meanwhile, a temperature controlling function may be provided to storage tank71to maintain the purified solvent within storage tank71to, for example, a room temperature at all time. The reason why the solvent is maintained to the room temperature is that, because wafer W and resist liquid are normally maintained to the room temperature at the time of processing, the in-plane uniformity in the resist film coating processing may be improved by decreasing the temperature difference between the solvent and the substrate.

A mechanism configured to reduce the pressure within the system by discharging the gas within the system from gas valve85may be used in place of the suction/discharge device of the carrier gas. When the pressure within the system is increased, gas valve85is opened and discharging valve76is closed. At that time, the discharge of the solvent is stopped. Meanwhile, when the solvent is ejected to wafer W, the solvent is controlled by closing gas valve85and opening discharging valve76. When the solvent before distilling is in a great quantity and it is expected that purified solvent will also be obtained in a great quantity, the suction/discharging device using, for example, a carrier gas may be omitted by controlling the discharge of the solvent by discharging valve76and gas valve85.

The examples of the processing liquids which may be handled in the present apparatus other than the solvent for pre-wetting processing may include, for example, MIBC used in a pre-wetting processing after forming a resist protective film, isopropyl alcohol used in cleaning a wafer, water used in rinsing a wafer, and a solvent used as so-called edge-remover to remove a resist film in a circumference edge of a wafer.