JP2010067811A - Substrate dryer and concentration calculation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate dryer capable of obtaining the concentration of a treatment gas without using a concentration meter even in the case that a high-concentration treatment gas is used. <P>SOLUTION: A control section 69 calculates, as a calculated concentration, the concentration of an organic solvent in a treatment gas on the basis of temperature-versus-concentrtaion dew point information stored in advance in a memory 71 per pressure based on the saturated vapor pressure curve of an organic solvent, measured pressure obtained from a pressure gauge 56, and a measured temperature obtained from a thermometer 57. This calculated concentration is shown in a display section 73. Therefore, it is possible to obtain the concentration of an isopropyl alcohol in the treatment gas without using a concentration meter, and the information can be sent to an operator of the dryer. Furthermore, the configuration of the dryer can be simplified, because a pump of a strong pressure reduction capacity and a capture section for the treatment gas are not required, thereby reducing the cost of the dryer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  In the present invention, a substrate such as a semiconductor wafer or a glass substrate (hereinafter simply referred to as a substrate) for a liquid crystal display device is subjected to treatment such as cleaning and etching with a treatment liquid, and then reduced pressure to reduce the organic solvent. The present invention relates to a substrate drying apparatus and a concentration calculation method for drying a substrate in an atmosphere of a processing gas containing steam.

  Conventionally, as this type of apparatus, a processing tank for storing a processing liquid and containing a substrate, a chamber surrounding the processing tank, and a vapor of an organic solvent (for example, isopropyl alcohol (IPA)) provided in the chamber A solvent vapor supply nozzle for supplying a sample gas as a processing gas together with a carrier gas, a sampling unit for deriving the processing gas in the chamber as a sample gas to the outside of the chamber, a dilution unit for diluting the sampled sample gas with a diluent gas, Examples include a concentration meter that measures the concentration of the processing gas in the gas, and a calculation unit that calculates the concentration of the processing gas before dilution based on the flow rate and concentration measurement value of the sample gas and the dilution gas (for example, Patent Documents 1 and 2).

In the apparatus having the above configuration, even a high concentration processing gas can be measured with a densitometer, and the substrate can be processed with a high concentration processing gas, so that it is possible to enhance the processing effect such as the drying processing of the substrate. . Recently, in order to supply a higher concentration of processing gas into the chamber, the inside of the chamber is decompressed by a decompression pump, and the interior of the vapor tank storing the organic solvent is also decompressed to enter the chamber. There is an apparatus for supplying a processing gas.
JP 2007-294859 A JP 2007-271090 A

However, the conventional example having such a configuration has the following problems.
That is, in the conventional apparatus, since the degree of decompression in the chamber is large, it is necessary to collect the processing gas from the chamber to the collection unit by suction with a decompression force stronger than that of the decompression pump. It is necessary to provide a densitometer capable of measuring the above, but a densitometer that can be measured particularly under high vacuum is very expensive, leading to an increase in the cost of the apparatus.

  The present invention has been made in view of such circumstances, and a substrate drying apparatus that can determine the concentration of a processing gas without using a densitometer, even when a high-concentration processing gas is used. An object is to provide a concentration calculation method.

In order to achieve such an object, the present invention has the following configuration.
That is, the invention described in claim 1 is a substrate drying apparatus that performs a drying process on a substrate with a processing gas, a chamber that accommodates the substrate, a solvent vapor generation unit that generates an organic solvent vapor, and the solvent vapor. A generating part and the inside of the chamber are connected in communication, a supply pipe for supplying a processing gas containing vapor of an organic solvent into the chamber, a decompression means for decompressing the inside of the chamber, and a pressure for measuring the pressure in the chamber A thermometer for measuring the temperature in the chamber, a storage means for preliminarily storing dew point information of temperature versus concentration for each pressure based on a saturated vapor pressure curve of the organic solvent, and the decompression means for the chamber After reducing the inside and introducing the processing gas from the solvent vapor generating section into the chamber, the measured pressure measured by the pressure gauge, the measured temperature measured by the thermometer, Based on the point information, and is characterized in that it comprises a calculating means for determining the concentration of the organic solvent in the process gas as calculated concentration, and a concentration display means for displaying the calculated concentrations.

  [Operation / Effect] According to the invention described in claim 1, the calculating means stores the dew point information of the temperature versus the concentration for each pressure based on the saturated vapor pressure curve of the organic solvent (predetermined pressure) stored in the storage means in advance. Based on the information representing the theoretical dew point below), the measured pressure, and the measured temperature, the concentration of the organic solvent in the processing gas is calculated as the calculated concentration. This calculated concentration is displayed on the concentration display means. Therefore, the concentration of the organic solvent in the processing gas can be obtained without using a densitometer, and the operator of the apparatus can be notified. In addition, since a pump with a strong decompression force and a processing gas sampling unit are not required, the configuration can be simplified and the apparatus cost can be reduced.

  The saturated vapor pressure curve is a curve showing the saturated vapor pressure at each temperature. For example, the saturated vapor pressure at atmospheric pressure is set to 100% with reference to atmospheric pressure (101.3 [kPa]). For example, a saturated vapor pressure curve can be converted to a temperature versus concentration dew point curve. If this is performed for various pressures, dew point information of temperature versus concentration for each pressure can be obtained. Therefore, the concentration of the organic solvent in the process gas can be calculated based on the measurement pressure, the measurement temperature, and the dew point information.

  In the present invention, it further comprises condensation detection means for detecting that the organic solvent in the processing gas has condensed in the chamber, and the calculation means obtains the calculated concentration after the condensation detection means detects condensation. (Claim 2). The dew point information is obtained based on the saturated vapor pressure curve of the organic solvent. Therefore, the concentration of the organic solvent in the processing gas can be accurately calculated by calculating the concentration after the condensation detecting means detects that the organic solvent contained in the processing gas has condensed.

  In the present invention, the dew condensation detection unit includes a reflection member attached in the chamber and having an arbitrary reflectance, and a reflected light detection unit that detects reflected light of the reflection member, and the calculation unit includes: It is preferable to determine that condensation has occurred when the detected reflected light intensity has decreased to a predetermined value. When the organic solvent is condensed on the reflecting member, the reflectance of the reflecting member is lowered. Therefore, when the reflected light intensity detected by the reflected light detecting means is lowered to a predetermined value, it can be determined that the organic solvent is condensed. Therefore, it is possible to determine the dew point at a relatively simple configuration.

  Further, in the present invention, a processing tank for storing a substrate and storing a processing liquid is provided in the chamber, and a nozzle to which the supply pipe is connected is provided above the inside of the chamber. (Claim 4). After the substrate is immersed in the treatment liquid in the treatment tank and the treatment is performed, the treatment gas can be supplied from the nozzle into the chamber to continue the drying treatment.

  According to a fifth aspect of the present invention, in the concentration calculation method for calculating the concentration of the organic solvent in the processing gas, the process of introducing the processing gas containing the vapor of the organic solvent into the decompressed chamber and the substrate are accommodated. Based on the process of measuring the pressure in the chamber as the measurement pressure and measuring the temperature in the chamber containing the substrate as the measurement temperature and the saturated vapor pressure curve of the organic solvent, A step of obtaining the concentration of the organic solvent in the processing gas as a calculated concentration based on the dew point information of the concentration, the measurement pressure, and the measurement temperature; and a step of displaying the calculated concentration. It is what.

  [Operation / Effect] According to the invention described in claim 5, after the processing gas is introduced into the decompressed chamber, the pressure in the chamber is measured as the measurement pressure, and the temperature in the chamber is measured as the measurement temperature. Based on the measurement pressure, the measurement temperature, and dew point information obtained in advance, the concentration of the organic solvent in the processing gas can be calculated. Therefore, the concentration of the organic solvent in the processing gas can be obtained without using a concentration meter.

  In the present invention, it is preferable that the process of obtaining the calculated concentration is performed after the organic solvent in the processing gas has condensed in the chamber.

  According to the substrate drying apparatus of the present invention, the calculation means stores the dew point information of the temperature versus the concentration for each pressure based on the saturated vapor pressure curve of the organic solvent, the measurement pressure, and the measurement temperature, which are stored in advance in the storage means. Based on the above, the concentration of the organic solvent in the processing gas is calculated as the calculated concentration. This calculated concentration is displayed on the concentration display means. Therefore, the concentration of the organic solvent in the processing gas can be obtained without using a densitometer, and the operator of the apparatus can be notified. In addition, since a pump with a strong decompression force and a processing gas sampling unit are not required, the configuration can be simplified and the apparatus cost can be reduced.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram illustrating a schematic configuration of a substrate drying apparatus according to an embodiment.

  The substrate drying apparatus according to the present embodiment includes a processing tank 1 that stores a processing liquid. The processing tank 1 stores a processing liquid and can accommodate a plurality of substrates W in an upright posture. Two supply / exhaust pipes 3 are provided at the bottom of the processing tank 1 and have a long axis along a direction (paper surface direction) in which a plurality of substrates W are aligned. Has been. One end of a pipe 5 is connected to each supply / exhaust pipe 3 in communication, and the other end of the pipe 5 is branched into a supply pipe 7 and a suction pipe 9. The supply pipe 7 is connected in communication with a processing liquid supply source 11, and the flow rate thereof is controlled by a processing liquid valve 13 provided in the supply pipe 7. The suction pipe 9 is connected to a vacuum exhaust pump 15 and is opened and closed by an exhaust valve 17 provided in the suction pipe 9. The processing liquid supply source 11 supplies hydrofluoric acid (HF), a mixed liquid of sulfuric acid / hydrogen peroxide water, pure water, or the like to the supply pipe 7 as a processing liquid.

  The processing tank 1 is surrounded by a chamber 19. The chamber 19 includes an upper cover 21 that can be freely opened and closed. The lifter 22 that holds the plurality of substrates W in a standing posture is moved between a “standby position” above the chamber 19, a “processing position” inside the processing tank 1, and the processing tank 1 by a driving mechanism (not shown). Therefore, it can be moved over a “drying position” corresponding to the inside of the chamber 19.

  A pair of solvent nozzles 23 and a pair of inert gas nozzles 25 corresponding to the “nozzles” of the present invention are disposed below the upper cover 21 and on the upper inner wall of the chamber 19. One end side of a supply pipe 27 for supplying a processing gas containing an organic solvent vapor is connected to the solvent nozzle 23 in communication. The other end side of the supply pipe 27 is connected to the solvent vapor generation unit 29 in communication. A steam valve 31 for adjusting the flow rate of the solvent vapor and an in-line heater 33 for heating the processing gas containing the organic solvent vapor are disposed in the supply pipe 27 in order from the upstream side. Since the supply pipe 27 includes the in-line heater 33, it is possible to reduce the condensation of the organic solvent in the processing gas in the supply pipe 27, and it is possible to prevent the organic solvent concentration in the processing gas from being lowered.

  The solvent vapor generator 29 is provided with a heater 35 for heating the stored organic solvent. In the solvent vapor generation unit 29, for example, isopropyl alcohol (IPA) is stored in the internal space as an organic solvent. Note that hydrofluoroether (HFE) or the like may be used as the organic solvent instead of isopropyl alcohol. In addition, a solvent supply source 41 for supplying an organic solvent is connected to the solvent vapor generating section 29 in communication.

One end of a supply pipe 43 is connected to the inert gas nozzle 25 in communication. The other end side of the supply pipe 43 is connected in communication with an inert gas supply source 45 that supplies an inert gas. The inert gas, for example, nitrogen gas (N _2). The amount of inert gas supplied from the inert gas supply source 45 is adjusted by an inert gas valve 47. An in-line heater 49 is attached to the supply pipe 43 on the downstream side of the inert gas valve 47. The in-line heater 49 heats the inert gas from the inert gas supply source 45 to a predetermined temperature.

  The chamber 19 is connected to an exhaust pipe 51 that can discharge the gas inside the chamber 19. The exhaust pipe 51 is provided with an opening / closing valve 52 and an exhaust pump 53. The chamber 19 is provided with a breathing valve 55 for eliminating the reduced pressure state. Furthermore, a pressure gauge 56 for detecting internal pressure, a thermometer 57 for detecting internal temperature, and a dew condensation sensor 58 for detecting internal dew condensation are attached to the chamber 19. .

  The vacuum exhaust pump 15 and the exhaust pump 53 described above correspond to the “pressure reducing means” in the present invention. Further, the dew condensation sensor 58 corresponds to the “dew condensation detection means” in the present invention.

  A discharge port 59 is disposed at the bottom of the processing tank 1. A QDR valve 61 is attached to the discharge port 59. When the processing liquid in the processing tank 1 is discharged from the QDR valve 61, the processing liquid is temporarily discharged to the bottom of the chamber 19. A discharge pipe 65 connected to the gas-liquid separator 63 is attached to the bottom of the chamber 19. A drain valve 67 is attached to the drain pipe 65. The gas-liquid separator 63 has a function of taking in gas and liquid from the exhaust pipe 51 and the exhaust pipe 65 and separating and discharging them.

  The above-described processing liquid valve 13, vacuum exhaust pump 15, exhaust valve 17, upper cover 21, lifter 22, solvent vapor generator 29, steam valve 31, inline heater 33, heater 35, inert gas valve 47, inline heater 49 The on-off valve 52, the exhaust pump 53, the breathing valve 55, the QDR valve 61, the drainage valve 67, and the like are comprehensively controlled by a control unit 69 corresponding to “calculation means” in the present invention. The control unit 69 has a storage unit 71 corresponding to the “storage unit” in the present invention and a display corresponding to the “concentration display unit” in the present invention, which is used for notifying the operator of the measurement pressure and the measured concentration. The unit 73 is connected. Further, the control unit 69 determines whether or not the pressure in the chamber 19 has reached the saturated vapor pressure of isopropyl alcohol based on the measurement pressure of the pressure gauge 56 and the heating temperature of the heater 35 of the solvent vapor generation unit 29. Then, processing is performed as described later. Further, as will be described later, the control unit 69 obtains the concentration of isopropyl alcohol based on the measured pressure of the pressure gauge 56, the measured temperature of the thermometer 57, and the dew point information of the storage unit 71, and the concentration is Processing is performed by determining whether or not the processing is appropriate. Whether or not the process is appropriate is determined based on an allowable value (for example, 3%) stored in the storage unit 71 in advance.

  The storage unit 71 includes a control program executed by the control unit 69, a recipe that defines the processing procedure, dew point information (described later in detail) and a saturated vapor pressure curve according to the organic solvent stored in the solvent vapor generation unit 29. Data is stored.

  Next, dew point information will be described with reference to FIGS. 2 is a graph showing a saturated vapor pressure curve of isopropyl alcohol, FIG. 3 is a graph showing a theoretical dew point at atmospheric pressure, and FIG. 4 is a graph showing a theoretical dew point at each pressure.

  The solvent vapor generation unit 29 stores, for example, isopropyl alcohol (IPA), and the saturated vapor pressure curve data is, for example, as shown in FIG. This indicates that, for example, when the temperature in the chamber 19 is 82 ° C., the saturated vapor pressure is atmospheric pressure (101.3 [kPa]). In other words, it indicates that the temperature in the chamber 19 needs to be 82 ° C. or higher in order to maintain the isopropyl alcohol concentration in the processing gas in the chamber 19 at 100% under atmospheric pressure. Strictly speaking, the boiling point of isopropyl alcohol is 82.7 ° C., but is 82 ° C. for convenience of explanation.

  Based on the above saturated vapor pressure curve data, assuming that the isopropyl alcohol concentration in the processing gas at atmospheric pressure is 100% and the pressure in the chamber 19 is fixed, each vapor pressure is divided by atmospheric pressure. The volume concentration of isopropyl alcohol in the processing gas at atmospheric pressure can be calculated. This is a graph showing the theoretical dew point at atmospheric pressure shown in FIG.

  The above theoretical dew point is at atmospheric pressure, but the theoretical dew point obtained for various pressures is a graph showing the theoretical dew point at each pressure in FIG. In the present invention, since the inside of the chamber 19 is decompressed and processed, in FIG. 4, as an example, a pressure half the atmospheric pressure (50.65 [kPa]), 30 [kPa], 20 [kPa], 15 [kPa] is exemplified. For example, when the measurement pressure in the chamber 19 is 50.65 [kPa] and the measurement temperature is 60 [° C.], the concentration of isopropyl alcohol in the process gas is 75 [%]. The graph showing the theoretical dew point shown in FIG. 4 corresponds to “dew point information” in the present invention. The dew point information is stored in advance in the storage unit 71 as described above, and is appropriately referred to by the control unit 69.

  Next, the dew condensation sensor 58 will be described with reference to FIGS. 5 is a plan view showing a schematic configuration of the dew condensation sensor, and FIG. 6 is a graph schematically showing an example of an output signal of the dew condensation sensor.

  The condensation sensor 58 includes, for example, a reflection type optical sensor 75 and a reflection member 77. The reflection type optical sensor 75 includes a light projecting unit 79 and a light receiving unit 81, and a signal indicating the light intensity received by the light receiving unit 81 is output from the signal processing unit 83. The reflection member 77 is configured by a plate-like member whose reflection surface 85 has an arbitrary reflectance. The reflection type optical sensor 75 and the reflection member 77 are attached in the chamber 19 with a predetermined interval, and the processing gas can flow within the interval. Accordingly, when isopropyl alcohol in the processing gas is condensed in the chamber 19, isopropyl alcohol is also condensed on the reflecting surface 85. Then, since the reflectance of the reflecting surface 85 is lowered, the light intensity signal output from the signal processing unit 83 is lowered. This is, for example, as shown in FIG. That is, as the isopropyl alcohol concentration in the processing gas approaches 100%, the signal intensity begins to decrease, and when it reaches 100%, the signal intensity decreases rapidly. Therefore, by detecting this time point, it can be determined that isopropyl alcohol in the processing gas has condensed in the chamber 19. Therefore, based on the output signal from the signal processing unit 83, the control unit 69 can determine whether isopropyl alcohol has condensed. When it is determined that the isopropyl alcohol has condensed, the control unit 69 refers to the measured pressure of the pressure gauge 56, the measured temperature of the thermometer 57, and the dew point information, and isopropyl in the processing gas in the chamber 19 Determine the alcohol concentration.

  As described above, the dew point information (FIG. 4) is detected when the isopropyl alcohol in the processing gas is condensed. The processing gas is supplied into the chamber 19, and the isopropyl alcohol in the processing gas is detected in the chamber 19. This is because it is assumed that it is saturated.

  Next, an operation example of the substrate drying apparatus having the above-described configuration will be described with reference to FIG. FIG. 7 is a flowchart showing the operation of the substrate drying apparatus.

First, main operations will be described.
The control unit 69 opens the upper cover 21 and loads the lifter 22 holding a plurality of unprocessed substrates W from the “standby position” to the “drying position”. At this time, the drainage valve 67 remains open. Next, the control unit 69 performs an oxygen concentration reduction process in the chamber 19. Specifically, the upper cover 21 is closed, the inert gas valve 47 is opened, and the inert gas is supplied into the chamber 19 from the inert gas supply source 45 through the supply pipe 43 and the inert gas nozzle 25. . Thereby, the air in the chamber 19 is purged by the inert gas, and as a result, the oxygen concentration in the chamber 19 is reduced. Further, the control unit 69 lowers the lifter 22 from the “drying position” to the “processing position”.

  When the oxygen concentration in the processing tank 1 and the chamber 19 is reduced, the control unit 69 opens the processing liquid valve 13. Thereby, the processing liquid (for example, room temperature pure water) is supplied from the processing liquid supply source 11 to the processing tank 1, and the processing liquid overflowing from the upper part of the processing tank 1 is collected at the bottom of the chamber 19. The collected processing liquid is collected by the gas-liquid separator 63 through the discharge pipe 65. After the processing liquid is supplied to the processing tank 1 in this way, the control unit 69 performs the processing with the processing liquid on the substrate W while maintaining the lifter 22 at the “processing position” for a predetermined time.

  When a predetermined time elapses after the processing with the processing liquid is started, the control unit 69 operates the exhaust pump 53 while discharging the gas in the chamber 19 while maintaining the lifter 22 at the “processing position”. The QDR valve 61 is opened and the processing liquid is quickly discharged into the chamber 19. After the processing liquid in the processing tank 1 is completely discharged, the inert gas valve 47 is closed and the breathing valve 55 is closed to completely close the inside of the chamber 19. As a result, the substrate W processed with the processing liquid is exposed to the surroundings in the processing tank 1.

Step S1
The control unit 69 makes preparations for generating steam in the solvent vapor generating unit 29. Specifically, the power supplied to the heater 35 is controlled at a heating temperature (for example, 72 ° C.) in order to heat isopropyl alcohol. At this time, the steam valve 31 remains closed. Note that step S1 may be started during the operation before the main operation described above.

Step S2
Depressurization in the chamber 19 is started. Specifically, the drain valve 67 is closed, the exhaust valve 17 and the open / close valve 52 are opened, and the decompression of the chamber 19 by the exhaust pump 53 and the vacuum exhaust pump 15 is started. At this time, the pressure in the chamber 19 is sequentially measured by the pressure gauge 56, and the measured pressure is output to the control unit 69. In addition, a pressure value based on the measured pressure is output to the display unit 73 via the control unit 69, and is used to determine whether or not the decompression process is normally performed.

Step S3
The controller 69 reduces the pressure by the exhaust pump 53 and the vacuum drain pump 15 until the saturated vapor pressure of isopropyl alcohol at the heating temperature of the solvent vapor generating unit 29 becomes lower than the saturated vapor pressure.

  Note that step S3 may be omitted only for the determination in the following step S5.

Step S4
The control unit 69 opens the steam valve 31. Then, the solvent vapor generation unit 29 communicates with the chamber 19, and the isopropyl alcohol boils in the solvent vapor generation unit 29 to generate a large amount of isopropyl alcohol vapor. Furthermore, since the pressure in the chamber 19 is lower than the pressure in the solvent vapor generation unit 29, isopropyl alcohol vapor flows into the chamber 19 from the solvent vapor generation unit 29 according to the pressure difference. And the inside of the chamber 19 is made into a solvent vapor atmosphere by the solvent vapor | steam which flowed in in the chamber 19 by the pressure difference. At this time, the isopropyl alcohol condenses on the entire surface of the substrate W that is exposed from the processing solution at room temperature and has a very low temperature compared to the vapor of isopropyl alcohol. Then, the droplets of the processing liquid adhering to the entire surface of the substrate W are replaced with isopropyl alcohol. Further, at this time, the substrate W is subjected to the drying process while being accommodated in the processing tank 1 having a smaller volume than the chamber 19, so that the drying process is efficiently performed.

Step S5
Based on the output signal of the dew condensation sensor 58, the control unit 69 determines whether or not isopropyl alcohol vapor has dewed in the chamber 19. If there is no condensation, the determination process is repeated until it is determined that condensation has occurred. If it is determined that condensation has occurred, the process proceeds to the next step S6.

Step S6
The control unit 69 refers to the storage unit 71 and calculates the isopropyl alcohol concentration based on the measurement pressure, the measurement temperature, and the dew point information, and causes the display unit 73 to display the calculated concentration. By displaying on the display unit 73 together with the density calculation, the operator of the apparatus can know the current density value.

Step S7
The control unit 69 determines whether the calculated concentration is within the normal range based on the allowable value and branches the process. If the calculated concentration is not within the normal range, the process proceeds to step S8. In this step S8, for example, a display such as “density error occurrence!” Is displayed on the display unit 73 to notify the operator of the apparatus of the occurrence of abnormality, and the processing is temporarily stopped to wait for the operator's treatment. To do. On the other hand, if the calculated concentration is within the normal range, the process proceeds to step S9.

Step S9
The control unit 69 closes the exhaust valve 17 and the on-off valve 52 and stops the vacuum exhaust pump 15 and the exhaust pump 53. Thereby, the pressure in the chamber 19 is maintained in a state where the pressure has been reduced so far.

Steps S10 and S11
The control unit 69 lifts the lifter 22 from the “processing position” to the “drying position” after processing the solvent vapor for a predetermined time. Then, while maintaining this state, it is maintained for a predetermined time to finish the drying process.

Step S12
The controller 69 opens the breathing valve 55 and opens the inert gas valve 47 when a predetermined time has elapsed, and introduces the inert gas into the chamber 19. Then, the pressure in the chamber 19 is returned to atmospheric pressure. As a result, the pressure difference with the solvent vapor generating section 29 is eliminated, and the generation of isopropyl alcohol vapor is stopped. Thereafter, the steam valve 31 is closed.

  After the processing described above, the control unit 69 opens the upper cover 21 and moves the lifter 22 from the “drying position” to the “standby position”.

  As described above, according to the present embodiment, the control unit 69 stores the dew point information of the temperature versus the concentration for each pressure based on the saturated vapor pressure curve of isopropyl alcohol, which is stored in the storage unit 71 in advance, and from the pressure gauge 56. Based on the measured pressure and the measured temperature from the thermometer 57, the concentration of isopropyl alcohol in the processing gas is calculated as the calculated concentration. This calculated concentration is displayed on the display unit 73. Therefore, the concentration of isopropyl alcohol in the processing gas can be obtained without using a densitometer, and the operator of the apparatus can be notified. In addition, since a pump with a strong decompression force and a processing gas sampling unit are not required, the configuration can be simplified and the apparatus cost can be reduced.

  The dew point information is obtained based on the saturated vapor pressure curve of isopropyl alcohol. Therefore, the concentration of isopropyl alcohol in the processing gas can be accurately calculated by calculating the concentration after the condensation sensor 58 detects that the isopropyl alcohol contained in the processing gas has condensed.

  Further, a reflection member 77 is provided as the dew condensation sensor 58, and the characteristic that the reflectance of the reflection member 77 is reduced when the organic solvent is condensed on the reflection member 77 is utilized. be able to. Therefore, the concentration calculation timing can be made appropriate.

  The present invention is not limited to the above embodiment, and can be modified as follows.

  (1) In the embodiment described above, the condensation sensor 58 is provided, and the concentration calculation timing is determined based on the output of the condensation sensor 58. For example, after the supply of isopropyl alcohol vapor is started (the steam valve 31 is opened). After that, the time may be measured with a timer or the like provided in the control unit 69, and the concentration may be measured after a predetermined time has elapsed. Thereby, the dew condensation sensor 58 becomes unnecessary, and the apparatus cost can be reduced.

  (2) In the above-described embodiment, a configuration in which the processing tank 1 is provided in the chamber 19 is employed. However, for example, an apparatus configuration in which only the drying process is performed in the chamber 19 without including the processing tank 1 is employed. May be.

  (3) In the embodiment described above, the processing liquid is discharged from the processing tank 1 in order to expose the substrate W from the processing liquid. For example, the lifter 22 is processed while the processing liquid is stored in the processing tank 1. You may make it raise above the tank 1. FIG.

  (4) In the above-described embodiment, the dew condensation sensor 58 is constituted by the reflective optical sensor 75 and the reflective member 77. For example, an optical fiber having a distal end opened to the light projecting portion 79 of the reflective sensor 75 is used. A configuration may be adopted in which an optical fiber having a distal end opened in the same manner is attached to the light receiving unit 81 and the outer peripheral surfaces of both optical fibers are bonded to each other and the respective distal ends are suspended. Thus, in the non-condensing state, only light is emitted from the tip of the optical fiber and does not go to the light receiving unit 81. However, if condensation occurs, the organic solvent adheres as droplets to the tip of both optical fibers. The light is detected toward the light receiving unit 81. Condensation can also be detected by such a configuration.

  (5) In the above-described embodiments, the processing gas is described as including only isopropyl alcohol. However, the processing gas may include a small amount of inert gas.

It is a block diagram which shows schematic structure of the board | substrate drying apparatus which concerns on an Example. It is a graph which shows the saturated vapor pressure curve of isopropyl alcohol. It is a graph which shows the theoretical dew point at the time of atmospheric pressure. It is a graph which shows the theoretical dew point at each pressure. It is a top view which shows schematic structure of a dew condensation sensor. It is the graph which showed an example of the output signal of a dew condensation sensor typically. It is a flowchart which shows operation | movement of a board | substrate drying apparatus.

Explanation of symbols

W ... Substrate 1 ... Processing tank 3 ... Supply / exhaust pipe 7 ... Supply pipe 9 ... Suction pipe 11 ... Process liquid supply source 13 ... Process liquid valve 15 ... Vacuum exhaust pump 17 ... Exhaust valve 19 ... Chamber 21 ... Upper cover 22 ... Lifter 23 ... Solvent nozzle 31 ... Steam valve 35 ... Heater 41 ... Solvent supply source 43 ... Supply pipe 47 ... Inert gas valve 53 ... Exhaust pump 56 ... Pressure gauge 57 ... Thermometer 58 ... Condensation sensor 61 ... QDR valve 69 ... Control unit 71 ... Storage unit 73 ... Display unit 75 ... Reflective sensor 77 ... Reflective member

Claims (6)

In a substrate drying apparatus that performs a drying process on a substrate with a processing gas
A chamber for receiving a substrate;
A solvent vapor generating section for generating an organic solvent vapor;
A supply pipe for connecting the solvent vapor generation section and the chamber, and supplying a processing gas containing an organic solvent vapor to the chamber;
Pressure reducing means for reducing the pressure in the chamber;
A pressure gauge for measuring the pressure in the chamber;
A thermometer for measuring the temperature in the chamber;
Based on the saturated vapor pressure curve of the organic solvent, storage means for storing in advance dew point information of temperature versus concentration for each pressure;
After reducing the pressure in the chamber by the pressure reducing means and introducing the processing gas from the solvent vapor generation section into the chamber, the measured pressure measured by the pressure gauge, the measured temperature measured by the thermometer, Calculating means for determining the concentration of the organic solvent in the processing gas as a calculated concentration based on the dew point information;
Density display means for displaying the calculated density;
A substrate drying apparatus comprising: The substrate drying apparatus according to claim 1,
Condensation detection means for detecting that the organic solvent in the processing gas has condensed in the chamber,
The substrate drying apparatus, wherein the calculation means obtains a calculated concentration after the condensation detection means detects condensation. The substrate drying apparatus according to claim 2,
The dew condensation detection means
A reflective member mounted in the chamber and having an arbitrary reflectivity;
A reflected light detecting means for detecting reflected light of the reflecting member,
The substrate drying apparatus, wherein the calculating means determines that condensation has occurred when the detected reflected light intensity is reduced to a predetermined value. In the board | substrate drying apparatus in any one of Claim 1 to 3,
A chamber capable of accommodating a substrate and storing a processing solution in the chamber;
A substrate drying apparatus characterized by comprising a nozzle connected to the supply pipe in an upper part inside the chamber. In the concentration calculation method for calculating the concentration of the organic solvent in the processing gas,
Introducing a process gas containing an organic solvent vapor into the decompressed chamber;
Measuring the pressure in the chamber containing the substrate as the measurement pressure, and measuring the temperature in the chamber containing the substrate as the measurement temperature;
Based on the saturated vapor pressure curve of the organic solvent, the concentration of the organic solvent in the process gas is calculated based on the dew point information of the temperature versus concentration for each pressure, the measured pressure, and the measured temperature. The process of determining the concentration,
A process of displaying the calculated concentration;
A density calculation method comprising: In the density | concentration calculation method of Claim 5,
The process of obtaining the calculated concentration is performed after the organic solvent in the processing gas has condensed in the chamber.

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