JP4916956B2 - Substrate processing equipment - Google Patents

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 a treatment such as cleaning and etching with a treatment liquid, and then the substrate is dried with a solvent vapor. The present invention relates to a substrate processing apparatus.

Conventionally, as this type of device, the inside of the chamber is depressurized and a solvent vapor, for example, isopropyl alcohol (IPA) vapor is supplied into the chamber to replace the processing liquid adhering to the substrate with the solvent vapor, and the substrate is dried. (For example, refer to Patent Document 1). Since the solvent concentration is closely related to the degree of drying of the substrate, the concentration of the solvent is measured with a densitometer while the gas in the chamber is sucked into the measuring tube with a small sampling pump.
Japanese Patent Laid-Open No. 9-190997

However, the conventional example having such a configuration has the following problems.
In other words, since the conventional apparatus does not support the measurement under reduced pressure, the pressure inside the chamber cannot be reduced at the timing of concentration measurement. There is a problem that it is not possible to measure the solvent concentration. In addition, since the densitometer cannot measure a high concentration of solvent, it is necessary to perform measurement after diluting the solvent concentration with an inert gas such as nitrogen gas, and it is impossible to measure the exact solvent concentration. There is a problem that excess exhaust increases due to dilution with gas or the like.

  The present invention has been made in view of such circumstances, and by enabling measurement under reduced pressure, it is possible to measure an accurate solvent concentration and suppress excessive exhaust. An object of the present invention is to provide a substrate processing apparatus that can be used.

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 processing apparatus for drying a substrate processed with a processing solution with a solvent vapor, a chamber for storing the substrate, and a solvent vapor supply means for supplying the solvent vapor into the chamber. The decompression means for decompressing the inside of the chamber, the measurement pipe communicating with the chamber, the vacuum-compatible concentration measurement means provided in the measurement pipe, and the gas in the chamber are sucked through the measurement pipe While the inside of the chamber is decompressed by the suction means and the decompression means, the solvent vapor is supplied from the solvent vapor supply means, and the vacuum is performed while the suction pipe sucks the gas in the chamber into the measurement pipe. and a control means for measuring the solvent concentration by the corresponding type concentration measuring means, the vacuum-compatible concentration measurement means includes a cell for circulating the gas Infrared irradiation means for irradiating the cell with infrared rays, detection means for detecting the infrared intensity transmitted through the cell, and the infrared intensity and solvent concentration at the degree of vacuum created in advance according to the degree of pressure reduction by the pressure reduction means Storage means for storing a calibration curve representing the correspondence relationship of, and a calculation means for calculating a solvent concentration based on the infrared intensity and the calibration curve by the detection means, and the measurement pipe has the vacuum-compatible concentration A pressure adjusting valve disposed upstream of the measuring means; and a pressure measuring means disposed between the pressure adjusting valve and the vacuum-compatible concentration measuring means, and is measured by the pressure measuring means. that the measurement pipe pressure is characterized in the this fed back controlled degree of vacuum as the target value in the calibration curve.

[Operation / Effect] According to the first aspect of the present invention, the control means causes the solvent vapor to be supplied from the solvent vapor supply means while the pressure in the chamber is reduced by the pressure reduction means, and the suction pipe supplies the chamber to the measurement pipe. The solvent concentration is measured by a vacuum-compatible concentration measuring means while sucking the gas inside. Since the concentration measurement is a vacuum-compatible type, the concentration of the solvent vapor can be measured under a reduced pressure environment, and the concentration of the solvent vapor under a dry environment can be measured. Therefore, the solvent concentration can be accurately controlled, and the uniformity of the substrate drying process can be improved. Moreover, since it is not necessary to dilute the solvent vapor, it is possible to suppress excessive exhaust.
In addition, the calculation means detects the infrared intensity irradiated from the infrared irradiation means and passes through the cell by the detection means, and calculates the solvent concentration based on the infrared intensity and the calibration curve. Measurement is possible. In addition, by changing the degree of decompression of the calibration curve, measurement is possible regardless of the degree of decompression in the chamber.
Furthermore, since the pressure in the measurement pipe matches the degree of decompression in the calibration curve, the calculation means can accurately determine the concentration based on the calibration curve.

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Further, in the present invention, the measuring pipe is preferably provided with heating means on the upstream side of the vacuum-responsive density measuring device (claim 2). It is possible to prevent the concentration of the solvent vapor from condensing and measuring the concentration until the concentration is measured, thereby improving the accuracy of the concentration measurement.

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According to the substrate processing apparatus of the present invention, the control means causes the solvent vapor to be supplied from the solvent vapor supply means while the pressure in the chamber is reduced by the pressure reducing means, and the gas in the chamber is sucked into the measurement pipe by the suction means. The solvent concentration is measured by vacuum-compatible concentration measuring means. Since the concentration measurement is a vacuum-compatible type, the solvent concentration can be measured in a reduced pressure environment, and the concentration of the solvent vapor in a dry environment can be measured. Therefore, the solvent concentration can be accurately controlled, and the uniformity of the substrate drying process can be improved. Further, since it is not necessary to dilute the solvent vapor for the measurement, it is possible to suppress excessive exhaust.
In addition, the calculation means detects the infrared intensity irradiated from the infrared irradiation means and passes through the cell by the detection means, and calculates the solvent concentration based on the infrared intensity and the calibration curve. Measurement is possible. In addition, by changing the degree of decompression of the calibration curve, measurement is possible regardless of the degree of decompression in the chamber.
Furthermore, since the pressure in the measurement pipe matches the degree of decompression in the calibration curve, the calculation means can accurately determine the concentration based on the calibration curve.

An embodiment 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 processing apparatus according to an embodiment.

The substrate processing apparatus includes a processing tank 1 for storing a processing liquid. The processing tank 1 is configured to store a processing liquid and accommodate a plurality of substrates W in an upright posture. Two ejection pipes 7 for supplying a processing liquid into the processing tank 1 have a long axis at the bottom of the processing tank 1 along the direction (paper surface direction) in which a plurality of substrates W are aligned. Is arranged. The ejection pipe 7 is connected to a processing liquid supply source 15 through a supply pipe 11, and the flow rate thereof is controlled by a processing liquid valve 17 provided in the supply pipe 11. The processing liquid supply source 15 supplies chemical liquid such as hydrofluoric acid (HF), sulfuric acid / hydrogen peroxide solution (H ₂ SO ₄ / H ₂ O ₂ ), or pure water as a processing liquid. .

  The processing tank 1 is surrounded by a chamber 27. The chamber 27 includes an upper cover 29 that can be opened and closed. The lifter 31 that holds the plurality of substrates W in a standing posture is configured to be movable between a “standby position” that is above the processing tank 1 and a “processing position” that is inside the processing tank 1.

  A pair of solvent nozzles 33 is disposed below the upper cover 29 and on the upper inner wall of the chamber 27. One end side of a supply pipe 35 is connected to the solvent nozzle 33 in communication. The other end side of the supply pipe 35 is connected in communication with a solvent vapor supply source 37. The supply pipe 35 is provided with a steam valve 39 for adjusting the flow rate of the solvent vapor. Examples of the solvent supplied from the solvent vapor supply source 37 include isopropyl alcohol (IPA).

  The solvent nozzle 33 described above corresponds to the solvent vapor supply means in the present invention.

  A vacuum pump 49 is disposed in the chamber 27 via an exhaust valve 51. The decompression pump 49 corresponding to the decompression means in the present invention is for exhausting the gas inside the chamber 27. The degree of pressure reduction is, for example, 10 to 20 kPa (absolute pressure reference). Incidentally, in the absolute pressure standard, the complete vacuum is 0 kPa and the atmospheric pressure is 101 kPa.

  A discharge port 53 is formed at the bottom of the processing tank 1. A QDR valve 55 is attached to the discharge port 53. When the processing liquid in the processing tank 1 is discharged from the QDR valve 55, the processing liquid is once discharged to the bottom of the chamber 27. A discharge pipe 57 is attached to the bottom of the chamber 27, and a drain valve 59 is attached to the discharge pipe 57.

  A measurement pipe 61 is disposed at one part of the chamber 27. In the measurement pipe 61, an in-line heater 62, a pressure adjustment valve 63, a pressure gauge 65, a vacuum-compatible concentration meter 67, and a sampling pump 69 are arranged in this order from the chamber 27 side. Since the measuring pipe 61 is provided with an in-line heater 62 on the most upstream side, the concentration of the solvent vapor changes until the solvent vapor is condensed inside the measuring pipe 61 and the concentration is measured by the vacuum-compatible concentration meter 67. Can be prevented, and the accuracy of concentration measurement can be improved.

  Note that the pressure gauge 65 corresponds to the pressure measuring means in the present invention.

  The vacuum-compatible densitometer 67, which will be described in detail later, is configured to be able to measure the solvent concentration in the gas under reduced pressure in the chamber 27, and a typical example is an infrared absorption method. Further, it is preferable that the sampling pump 69 can reduce the pressure to a degree of pressure lower than that of the vacuum pump 49 described above, for example, about 5 kPa (absolute pressure reference). However, the absolute amount discharged at that time does not reach the vacuum pump 49.

  The processing liquid valve 17, the upper cover 29, the lifter 31, the steam valve 39, the vacuum pump 49, the exhaust valve 51, the QDR valve 55, the drain valve 59, the in-line heater 62, the pressure adjustment valve 63, and the vacuum-compatible concentration meter. 67. The operations of the sampling pump 69 and the like are comprehensively controlled by the control unit 71.

  For example, the control unit 71 operates each unit as follows to perform processing on the substrate W by a series of operations. First, the lifter 31 is moved to a processing position in the processing tank 1 to perform processing with a chemical solution, and subsequently to cleaning with pure water. After the pure water cleaning is completed, the QDR valve 55 and the drainage valve 59 are opened in this order to rapidly drain the pure water in the treatment tank 1, and then the vacuum is maintained with the QDR valve 55 and the drainage valve 59 closed. The inside of the chamber 27 is reduced to a predetermined pressure by the pump 49. Thereafter, the solvent vapor is supplied from the solvent nozzle 33 into the chamber 27, and the solvent vapor is supplied around the substrate W at the processing position. After the predetermined time has elapsed, the supply of the solvent vapor is stopped, and then the lifter 31 at the processing position is raised and moved to the standby position. As a result, the substrate W is cleaned and dried. Among the operations described above, “concentration measurement” described later is always performed when the solvent vapor is supplied.

  The vacuum-compatible densitometer 67 corresponds to the vacuum-compatible concentration measuring means in the present invention, the sampling pump 69 corresponds to the suction means in the present invention, and the control unit 71 corresponds to the control means in the present invention.

  Reference is now made to FIG. FIG. 2 is a diagram showing a schematic configuration of a vacuum-compatible densitometer.

  The vacuum-compatible densitometer 67 includes a cell 73 at one part of the measurement pipe 61. The cell 73 includes a pair of transmitting members 75 that transmit infrared light and are provided at positions facing each other across the gas flowing through the measurement pipe 61. On one side of the cell 73, a light source 77 for irradiating infrared rays and a detector 79 for detecting the intensity of infrared rays transmitted through the cell 73 are disposed. The detector 79 includes a reference detector 81 and a reference detector 83, and includes an optical filter (not shown) that removes infrared rays having unnecessary wavelengths on the light incident side. The infrared intensity signals detected by each are supplied to a calculation unit 85 provided with a preamplifier (not shown) in the previous stage. The calculation unit 85 calculates the solvent concentration based on the light amount difference based on the Lambert-Beer law. At this time, a calibration curve (described later) stored in the storage unit 87 is referred to. Then, the calculated solvent concentration is output to the control unit 71. The calculation unit 85 automatically corrects the signal of the reference detector 83 based on the standard signal from the standard detector 81, and can accurately calculate the solvent concentration even if the light intensity of the light source 77 changes. ing.

  The light source 77 described above corresponds to the infrared irradiation unit in the present invention, the detector 79 corresponds to the detection unit in the present invention, the calculation unit 85 corresponds to the calculation unit in the present invention, and the storage unit 87 in the present invention. It corresponds to storage means.

The calibration curve is, for example, as shown in FIG.
That is, the data represents the correspondence between the infrared intensity (absorbance) and the solvent concentration, and is created in advance at a predetermined pressure reduction degree. In FIG. 3, the calibration curve is represented by a linear function, but this is an example, and data such as a quadratic function may be obtained.

  The control unit 71 feedback-controls the pressure adjustment valve 63 so that the pressure of the pressure gauge 65 matches the target value with the degree of pressure reduction in the calibration curve as the target value. Thereby, the gas in the chamber 27 can be guided to the vacuum-compatible concentration meter 67 in a state where the degree of decompression in the calibration curve is obtained, and the concentration can be measured with high accuracy.

  Reference is now made to FIG. FIG. 4 is a flowchart showing processing related to density measurement. This flowchart shows the operation from the time when the supply of the solvent vapor is performed during the series of operations described above.

Steps S1-S3
The controller 71 opens the vapor valve 39 at a predetermined opening and starts supplying solvent vapor from the solvent nozzle 33 into the chamber 27. At this time, the sampling pump 69 is operated, and a part of the gas in the chamber 27 is sucked into the measurement pipe 61. Further, the pressure adjustment valve 63 is operated so that the pressure detected by the pressure gauge 65 matches the degree of pressure reduction in the calibration curve.

Steps S4 to S7
When the pressure matches the degree of pressure reduction in the calibration curve, the vacuum-compatible concentration meter 67 measures the concentration of the solvent vapor, and the control unit 71 determines whether or not the measured concentration value matches the predetermined solvent concentration target value. The process branches depending on whether That is, as a result of the concentration measurement, if the solvent concentration target value does not match, the steam valve 39 is operated to adjust the supply amount of the solvent vapor to the solvent nozzle 33. On the other hand, when it matches with the solvent concentration target value, the process is repeatedly executed from step S1 described above until the supply time of the solvent vapor elapses.

  As described above, the control unit 71 supplies the solvent vapor from the solvent nozzle 33 in a state where the pressure in the chamber 27 is reduced by the vacuum pump 49, and causes the sampling pipe 69 to suck the gas in the chamber 27 into the measurement pipe 61. However, the solvent concentration is measured by the vacuum-compatible densitometer 67. Since the concentration measurement is a vacuum-compatible type, the concentration measurement can be performed under a reduced pressure environment, and the concentration of the solvent vapor can be measured under a dry environment. Therefore, the solvent concentration can be accurately controlled, and the uniformity of the substrate drying process can be improved. Moreover, since it is not necessary to dilute the solvent vapor, it is possible to suppress excessive exhaust.

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

  (1) Although the processing tank 1 is provided in the chamber 27 in the above-described embodiment, only the chamber 27 that accommodates the substrate W may be used. In that case, it is only necessary to provide a support portion in the chamber 27 that only supports the plurality of substrates W in a standing posture.

  (2) In the embodiment described above, the measurement pipe 61 is provided with the in-line heater 62. However, the in-line heater 62 may be omitted when the concentration of the solvent vapor does not cause condensation.

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( 3 ) In the above-described embodiment, the sampling pump 69 is employed as the suction means. However, instead of this, an ejector that sucks the gas in the chamber 27 by supplying the gas for the suction operation may be used. Good. Examples of the gas for suction operation include inert gases such as nitrogen, air, and the like.

It is the block diagram which showed schematic structure of the substrate processing apparatus which concerns on an Example. It is the figure which showed schematic structure of the vacuum-type densitometer. It is the schematic diagram which showed an example of the calibration curve. It is the flowchart which showed the process which concerns on a density | concentration measurement.

Explanation of symbols

W ... Substrate 1 ... Processing tank 7 ... Jet pipe 33 ... Solvent nozzle 49 ... Vacuum pump 65 ... Pressure gauge 67 ... Vacuum-compatible densitometer 69 ... Sampling pump 71 ... Control part 77 ... Light source 79 ... Detector 85 ... Calculation part 87 … Storage

Claims (2)

In a substrate processing apparatus for drying a substrate processed with a processing liquid by solvent vapor,
A chamber for receiving a substrate;
Solvent vapor supply means for supplying solvent vapor into the chamber;
Pressure reducing means for reducing the pressure in the chamber;
A measurement pipe communicating with the chamber;
A vacuum-compatible concentration measuring means provided in the measurement pipe;
Suction means for sucking the gas in the chamber through the measurement pipe;
While the pressure inside the chamber is reduced by the pressure reducing means, the solvent vapor is supplied from the solvent vapor supply means, and the vacuum-compatible concentration measurement is performed while the gas in the chamber is sucked into the measurement pipe by the suction means. Control means for measuring the solvent concentration by means;
With
The vacuum-compatible concentration measuring means includes:
The reduced pressure created in advance according to the degree of pressure reduction by the pressure reducing means by the cell through which the gas flows, the infrared irradiation means for irradiating the cell with infrared rays, the detecting means for detecting the infrared intensity transmitted through the cell, and the pressure reducing means Storage means storing a calibration curve representing the correspondence between infrared intensity and solvent concentration in degrees, calculation means for calculating the solvent concentration based on the infrared intensity and the calibration curve by the detection means,
With
The measurement pipe includes a pressure regulating valve disposed upstream of the vacuum-compatible concentration measuring unit, and a pressure measuring unit disposed between the pressure regulating valve and the vacuum-compatible concentration measuring unit. And the pressure in the measurement pipe measured by the pressure measuring means is feedback controlled using the degree of pressure reduction in the calibration curve as a target value.
The substrate processing apparatus according to claim and this. The substrate processing apparatus according to claim 1 ,
The substrate processing apparatus, wherein the measurement pipe includes a heating means upstream of the vacuum-compatible concentration measuring means.

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