Substrate Processing Equipment

Abstract

To position a liquid surface of a processing liquid after a suck-back at a desired position with high accuracy.SOLUTION: In a substrate processing apparatus, a processing liquid is supplied from a processing liquid supply source 71 to a nozzle 51 in a state where a first valve 521 is opened, and a second valve 531 is closed. Also, in the state where the first valve 521 is closed, and the second valve 531 is opened, the processing liquid in a first pipe 52 is exhausted to a second pipe 53, and a sack back of the processing liquid in the nozzle 51 is performed. Then, on the basis of a measurement result by a flow amount sensor 56, an integrated exhaust flow amount as an integration flow amount of the processing liquid exhausted from the first pipe 52 to the second pipe 53 is calculated. A valve control part blocks the second valve 531 when the integrated exhaust flow amount reaches a predetermined sack back threshold value. Thus, a liquid surface of the processing liquid after the sack back can be positioned at high accuracy.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a substrate processing apparatus for processing a substrate. [Background technology]

[0002] Conventionally, in a manufacturing process of a semiconductor substrate (hereinafter simply referred to as a "substrate"), various processes are performed on the substrate. For example, a chemical solution such as an etching solution is supplied to the surface of the substrate held horizontally in a substrate processing apparatus, and chemical processing is performed.

[0003] In such substrate processing apparatuses, nozzles that eject processing liquid, such as chemical liquid, toward a substrate are connected to a processing liquid supply source via piping or the like. Patent Document 1 discloses a substrate processing apparatus that detects whether the processing liquid is flowing through the piping by measuring the electric charge generated by friction between the processing liquid and the inner wall surface of the piping. Patent Document 2 discloses a substrate processing apparatus in which a silicon-containing phosphoric acid aqueous solution is stored as the processing liquid in a supply tank, which is a processing liquid supply source. A new liquid replenishment pipe that connects the supply tank to a new liquid preparation tank for producing new processing liquid is provided with an integrating flow meter that measures the supply amount of the new liquid. Patent Document 3, on the other hand, proposes a substrate processing apparatus that can switch between recovering and draining the chemical liquid after supply to the substrate, and that switches from draining to recovering when the cumulative drainage flow rate (cumulative waste liquid flow rate) reaches a predetermined flow rate.

[0004] Furthermore, in the substrate processing apparatus described above, when the discharge of processing liquid from the nozzle is stopped, an operation (i.e., suck-back) may be performed to suck the processing liquid from the nozzle and return the liquid surface of the processing liquid from the nozzle tip to the piping side in order to prevent dripping from the nozzle (i.e., unintentional dripping of processing liquid from the nozzle tip).

[0005] In the substrate processing apparatus of Patent Document 4, it is proposed to suppress fluctuations in the operating speed of a suck-back valve used for suck-back in order to prevent suck-back defects. In this substrate processing apparatus, the air pressure of the suck-back valve, which sucks back processing liquid from the nozzle, is measured by a pressure gauge. The operating speed of the suck-back valve is then calculated by taking the time between the output of a trigger signal instructing the suck-back valve to operate and the time when the measured air pressure drops to a reference pressure as the actual operating time of the suck-back valve.

[0006] Furthermore, in the substrate processing apparatus of Patent Document 5, in order to suppress variation in the position of the front surface of the processing liquid remaining in the nozzle or piping after suck-back, a liquid level sensor is provided to detect the liquid level at a predetermined position on the piping, and the timing to stop suck-back is determined based on the output from the liquid level sensor. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6899228 [Patent Document 2] Patent No. 6917868 [Patent Document 3] Patent No. 6708508 [Patent Document 4] Patent No. 6932000 [Patent Document 5] Japanese Patent Application Laid-Open No. 2016-72337 Summary of the Invention [Problem to be solved by the invention]

[0008] During the suck-back of a processing liquid in a substrate processing apparatus, the amount of processing liquid sucked varies depending on the viscosity of the processing liquid, causing fluctuations in the liquid level of the processing liquid that has moved from the nozzle tip to the piping. Patent Document 5 proposes suppressing variations in the liquid level using a liquid level sensor, as described above. However, if a liquid shortage occurs during the suck-back (i.e., a phenomenon in which the liquid column of the processing liquid being sucked breaks midway and splits into two liquid columns), the processing liquid may remain closer to the nozzle tip than the liquid level detected by the liquid level sensor. In this case, the processing liquid level that should be detected (i.e., the liquid level of the processing liquid closest to the nozzle tip) cannot be detected, and the processing liquid level may deviate from the desired position. Furthermore, the liquid level sensor must be positioned near the desired liquid level, which reduces the design flexibility of the substrate processing apparatus.

[0009] The present invention has been made in view of the above-mentioned problems, and has as its object to position the liquid level of the processing liquid at a desired position with high accuracy after suck-back. [Means for solving the problem]

[0010] The invention described in claim 1 is a substrate processing apparatus for processing a substrate, comprising: a nozzle that ejects a processing liquid to be supplied to the substrate; a first pipe connecting a processing liquid supply source and the nozzle; a first valve arranged on the first pipe; a second pipe branching from the first pipe between the nozzle and the processing liquid supply source; a second valve arranged on the second pipe; a flow sensor that measures an instantaneous flow rate of the processing liquid discharged from the first pipe to the second pipe; and a valve control unit that controls the first valve and the second valve. When the first valve is open and the second valve is closed, the processing liquid is supplied from the processing liquid supply source to the nozzle. When the first valve is closed and the second valve is open, the processing liquid in the first pipe is discharged to the second pipe, thereby performing suckback of the processing liquid in the nozzle. Based on the measurement result by the flow sensor, an integrated discharge flow rate, which is the integrated flow rate of the processing liquid discharged from the first pipe to the second pipe, is calculated. The valve control unit closes the second valve when the integrated discharge flow rate reaches a predetermined suckback threshold.

[0011] A second aspect of the present invention is the substrate processing apparatus according to the first aspect, wherein the calculation of the integrated discharge flow rate is started in parallel with the closing of the first valve.

[0012] A third aspect of the present invention provides the substrate processing apparatus according to the first aspect, wherein the calculation of the integrated discharge flow rate is started a predetermined time after the first valve is closed.

[0013] The invention described in claim 4 is the substrate processing apparatus described in claim 1, wherein, when suck-back is performed, the second valve is opened before the first valve is closed, and calculation of the integrated discharge flow rate is started in parallel with the opening of the second valve.

[0014] The invention described in claim 5 is a substrate processing apparatus described in claim 1, further comprising an imaging unit that images the nozzle and an image monitoring unit that determines whether or not processing liquid is being ejected from the nozzle based on the output from the imaging unit, and calculation of the cumulative discharge flow rate is started when the image monitoring unit determines that ejection of processing liquid from the nozzle has stopped.

[0015] A sixth aspect of the present invention provides the substrate processing apparatus according to any one of the first to fifth aspects, wherein the flow rate sensor is disposed on the second pipe.

[0016] According to a seventh aspect of the present invention, in the substrate processing apparatus of any one of the first to fifth aspects, the flow rate sensor is disposed on the first pipe, and when the processing liquid is supplied from the processing liquid supply source to the nozzle, the flow rate sensor to Thus, the supply flow rate of the processing liquid is measured.

[0017] An eighth aspect of the present invention is the substrate processing apparatus according to any one of the first to seventh aspects, further comprising a storage unit that stores a plurality of suck-back thresholds corresponding to a plurality of types of processing liquids, respectively.

[0018] The invention described in claim 9 is the substrate processing apparatus described in claim 8, wherein the suck-back threshold corresponding to the processing liquid supplied at a temperature higher than room temperature is greater than the suck-back threshold corresponding to the processing liquid supplied at room temperature. [Effects of the Invention]

[0019] In the present invention, the liquid level of the processing liquid after suck-back can be positioned at a desired position with high precision. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a plan view of a substrate processing system including a substrate processing apparatus according to a first embodiment. [Figure 2] FIG. 2 is a side view of the substrate processing apparatus. [Figure 3]FIG. 2 is a diagram illustrating a configuration of a control unit. [Figure 4] FIG. 2 is a block diagram showing the functions of a control unit. [Figure 5] FIG. 2 is a block diagram showing a processing liquid supply unit. [Figure 6] FIG. 2 is a side view of the substrate processing apparatus. [Figure 7] FIG. 2 is a block diagram showing the functions of a control unit. [Figure 8] FIG. 10 is a block diagram showing a processing liquid supply unit of a substrate processing apparatus according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] 1 is a schematic plan view showing the layout of a substrate processing system 10 including a substrate processing apparatus according to a first embodiment of the present invention. The substrate processing system 10 processes semiconductor substrates 9 (hereinafter simply referred to as "substrates 9"). The substrate processing system 10 includes an indexer block 101 and a processing block 102 coupled to the indexer block 101.

[0022] The indexer block 101 includes a carrier holding unit 104, an indexer robot 105 (i.e., substrate transport means), and an IR movement mechanism 106. The carrier holding unit 104 holds a plurality of carriers 107, each capable of accommodating a plurality of substrates 9. The plurality of carriers 107 (e.g., FOUPs) are held by the carrier holding unit 104 in a state where they are arranged horizontally in the carrier arrangement direction (i.e., the up-and-down direction in FIG. 1). The IR movement mechanism 106 moves the indexer robot 105 in the carrier arrangement direction. The indexer robot 105 performs an unloading operation to unload the substrates 9 from the carriers 107, and a loading operation to load the substrates 9 into the carriers 107 held by the carrier holding unit 104. The substrates 9 are transported by the indexer robot 105 in a horizontal position.

[0023] On the other hand, the processing block 102 includes a plurality of (e.g., four or more) processing units 108 that process the substrates 9, and a center robot 109 (i.e., substrate transport means). The plurality of processing units 108 are arranged to surround the center robot 109 in a plan view. The plurality of processing units 108 perform various processes on the substrates 9. A substrate processing apparatus, which will be described later, is one of the plurality of processing units 108. The center robot 109 performs a load operation to load the substrates 9 into the processing units 108 and an unload operation to unload the substrates 9 from the processing units 108. Furthermore, the center robot 109 transports the substrates 9 between the plurality of processing units 108. The substrates 9 are transported in a horizontal position by the center robot 109. The center robot 109 receives the substrates 9 from the indexer robot 105 and passes the substrates 9 to the indexer robot 105.

[0024] Fig. 2 is a side view showing the configuration of the substrate processing apparatus 1. The substrate processing apparatus 1 is a single-wafer type apparatus that processes substrates 9 one by one. The substrate processing apparatus 1 performs liquid processing by supplying a processing liquid to the substrates 9. Fig. 2 shows a cross section of part of the configuration of the substrate processing apparatus 1.

[0025] The substrate processing apparatus 1 includes a substrate holding unit 31, a substrate rotation mechanism 33, a cup unit 4, a processing liquid supply unit 5, a control unit 8, and a chamber 11. The substrate holding unit 31, the substrate rotation mechanism 33, the cup unit 4, etc. are housed in the internal space of the chamber 11. An airflow forming unit 12 is provided in the canopy of the chamber 11, and supplies gas to the internal space to form a downward airflow (so-called downflow). For example, an FFU (fan filter unit) is used as the airflow forming unit 12. The control unit 8 is disposed outside the chamber 11 and controls the substrate holding unit 31, the substrate rotation mechanism 33, the processing liquid supply unit 5, etc.

[0026] As shown in FIG. 3 , the control unit 8 is, for example, a typical computer system including a processor 81, a memory 82, an input / output unit 83, and a bus 84. The bus 84 is a signal circuit connecting the processor 81, the memory 82, and the input / output unit 83. The memory 82 stores programs and various information. The processor 81 executes various processes (e.g., numerical calculations) using the memory 82 and other components in accordance with the programs and other components stored in the memory 82. The input / output unit 83 includes a keyboard 85 and a mouse 86 for receiving input from an operator, a display 87 for displaying output and other components from the processor 81, and a transmitter for transmitting output and other components from the processor 81. The control unit 8 may be a programmable logic controller (PLC), a circuit board, or the like. The control unit 8 may include any two or more components of a computer system, a PLC, a circuit board, or the like.

[0027] 4 is a block diagram showing functions realized by the control unit 8. The control unit 8 includes a storage unit 801, a valve control unit 802, and a calculation unit 803. The storage unit 801 is mainly realized by a memory 82 (see FIG. 3), and stores various information related to the substrate processing apparatus 1. The valve control unit 802 is mainly realized by a processor 81 (see FIG. 3), and controls a first valve 521 and a second valve 531 (described later) of the processing liquid supply unit 5. The calculation unit 803 is mainly realized by the processor 81, and performs various calculations related to the substrate processing apparatus 1.

[0028] The substrate holding unit 31 and substrate rotation mechanism 33 shown in FIG. 2 are each part of a spin chuck that holds and rotates the substrate 9. The substrate holding unit 31 holds the substrate 9 in a horizontal position from below. The substrate holding unit 31 is, for example, a mechanical chuck that mechanically supports the substrate 9. The substrate holding unit 31 includes a base unit 311 and a plurality of chucks 312. The base unit 311 is a substantially disk-shaped member centered on a central axis J1 that faces the up-down direction. The substrate 9 is disposed above the base unit 311 at a distance from the base unit 311.

[0029] The multiple chucks 312 are arranged on the outer periphery of the upper surface of the base portion 311 in a circumferential direction (hereinafter simply referred to as the "circumferential direction") centered on the central axis J1. The multiple chucks 312 are arranged, for example, at approximately equal angular intervals in the circumferential direction. In the substrate holding portion 31, the multiple chucks 312 hold the outer edge of the substrate 9. Note that the substrate holding portion 31 may be a chuck with another structure, such as a vacuum chuck.

[0030] The substrate rotation mechanism 33 is disposed below the substrate holding unit 31. The substrate rotation mechanism 33 rotates the substrate 9 together with the substrate holding unit 31 around the central axis J1. The substrate rotation mechanism 33 includes a shaft 331 and a motor 332. The shaft 331 is a substantially columnar or cylindrical member centered on the central axis J1. The shaft 331 extends in the vertical direction and is connected to the center of the lower surface of the base unit 311 of the substrate holding unit 31. The motor 332 is an electric rotary motor that rotates the shaft 331. The substrate rotation mechanism 33 may be a motor having another structure (for example, a hollow motor, etc.).

[0031] The processing liquid supply unit 5 supplies a processing liquid to the substrate 9 to perform liquid processing on the substrate 9. The processing liquid supply unit 5 includes a nozzle 51 and a first pipe 52. The nozzle 51 ejects the processing liquid from above the substrate 9 toward the upper main surface (hereinafter also referred to as the "upper surface 91") of the substrate 9. The processing liquid is, for example, an etching liquid used in etching the substrate 9. The etching liquid is supplied to the upper surface 91 of the substrate 9 at, for example, a temperature higher than room temperature (for example, 25°C). Note that the nozzle 51 may eject a chemical liquid other than the etching liquid, or various types of processing liquids other than chemical liquids (for example, a rinse liquid). These processing liquids may be supplied to the substrate 9 at a temperature higher than room temperature, or at a temperature equal to or lower than room temperature.

[0032] The processing liquid supply unit 5 may include a nozzle movement mechanism that moves the nozzle 51. The nozzle movement mechanism moves the nozzle 51 approximately horizontally, for example, between a supply position above the substrate 9 and a retracted position that is further outward from the outer edge of the substrate 9 in a radial direction (hereinafter simply referred to as the "radial direction") about the central axis J1. The nozzle movement mechanism includes, for example, an electric linear motor, an air cylinder, or a ball screw and an electric rotary motor. Furthermore, in addition to the nozzle 51, the processing liquid supply unit 5 may include another nozzle that ejects onto the substrate 9 a processing liquid of a different type from the processing liquid ejected from the nozzle 51.

[0033] 5 is a block diagram schematically illustrating the configuration of the processing liquid supply unit 5 of the substrate processing apparatus 1. In addition to the nozzle 51 and the first pipe 52 described above, the processing liquid supply unit 5 includes a first valve 521, a second pipe 53, a second valve 531, and a flow rate sensor 56.

[0034] The nozzle 51 is connected to the processing liquid supply source 71 via a first pipe 52. In the example shown in FIG. 5 , the first pipe 52 extends substantially horizontally from the processing liquid supply source 71, turns approximately 90° at a first bent portion 522, extends substantially vertically upward, turns approximately 90° at a second bent portion 523, extends substantially horizontally, and is connected to the nozzle 51. In the following description, a portion of the first pipe 52 between the processing liquid supply source 71 and the first bent portion 522 will be referred to as a “first portion 524,” a portion between the first bent portion 522 and the second bent portion 523 will be referred to as a “second portion 525,” and a portion between the second bent portion 523 and the nozzle 51 will be referred to as a “third portion 526.” The nozzle 51 extends substantially horizontally from the connection portion with the first pipe 52, turns approximately 90° near the tip, and extends substantially vertically downward. The first valve 521 is disposed on the first pipe 52. In the example shown in FIG. 5, the first valve 521 is provided at a first portion 524 of the first pipe 52.

[0035] The second pipe 53 is a pipe for sucking back. The second pipe 53 branches off from the first pipe 52 between the nozzle 51 and the processing liquid supply source 71. In the example shown in FIG. 5 , the second pipe 53 is connected to the first pipe 52 at a first bent portion 522 of the first pipe 52. That is, the second pipe 53 branches off from the first pipe 52 between the first valve 521 and the nozzle 51. The second pipe 53 extends substantially vertically downward from the first bent portion 522. A drain box 55 in which the processing liquid is stored is disposed below the second pipe 53. The lower end of the second pipe 53 is immersed in the processing liquid stored in the drain box 55.

[0036] 5, the second valve 531 is provided on the second pipe 53. In the example shown in Fig. 5, the second valve 531 is provided between the first bent portion 522 and the drain box 55. In addition, the second pipe 53 is provided with an orifice 532 at a position adjacent to the second valve 531 above the second valve 531 (i.e., between the second valve 531 and the first bent portion 522).

[0037] By controlling the valve control unit 802 (see FIG. 4), the second valve 531 is closed and the first valve 521 is opened, whereby the processing liquid used to process the substrate 9 is supplied from the processing liquid supply source 71 to the nozzle 51 via the first pipe 52 and is discharged from the tip of the nozzle 51 (i.e., the lower end of the nozzle 51) onto the upper surface 91 of the substrate 9. Then, by closing the first valve 521 by the valve control unit 802, the discharge of the processing liquid from the nozzle 51 is stopped.

[0038] Furthermore, by controlling the valve control unit 802 (see FIG. 4 ), the first valve 521 is closed and the second valve 531 is opened, whereby the processing liquid in the second pipe 53 flows toward the drain box 55 due to a siphon effect caused by the difference in height between the orifice 532 and the tip of the nozzle 51. As a result, the processing liquid in the first pipe 52 is discharged from the first bent portion 522 to the second pipe 53, and the processing liquid in the nozzle 51 is sucked back. When the suck back starts, the liquid level of the processing liquid in the nozzle 51 (i.e., the interface between the processing liquid and the surrounding atmosphere) moves from the tip of the nozzle 51 toward the first pipe 52. Note that when the suck back starts, the second valve 531 may be opened after the first valve 521 is closed, or may be opened slightly before the first valve 521 is closed, or may be opened approximately simultaneously with the closing of the first valve 521.

[0039] In the processing liquid supply unit 5, the valve control unit 802 closes the second valve 531, thereby stopping the suck-back of the processing liquid. In the processing liquid supply unit 5, the second pipe 53, the second valve 531, and the orifice 532 constitute a siphon-type (also called gravity-type) suck-back mechanism 50 that sucks back the processing liquid in the nozzle 51. Note that the drain box 55 may also be included in the suck-back mechanism.

[0040] The above-described suck-back occurs, for example, when a plurality of substrates 9 are continuously processed in the substrate processing apparatus 1, at the time when the supply of the processing liquid from the nozzle 51 to one substrate 9 is completed. As a result, the liquid level of the processing liquid located at the tip of the nozzle 51 at the time when the supply of the processing liquid to the substrate 9 is completed moves away from the tip toward the processing liquid supply source 71 and is located at a predetermined position within the nozzle 51 or the first pipe 52. The above-described suck-back also occurs, for example, when the supply of the processing liquid from the nozzle 51 is resumed after being stopped for a relatively long period of time, after the processing liquid has been pre-dispensed from the nozzle 51. In this case as well, the liquid level of the processing liquid located at the tip of the nozzle 51 at the time when the pre-dispensing is completed moves away from the tip toward the processing liquid supply source 71 and is located at a predetermined position within the nozzle 51 or the first pipe 52.

[0041] The flow rate sensor 56 measures the instantaneous flow rate (i.e., suck-back speed) of the processing liquid discharged from the first pipe 52 to the second pipe 53 when the suck-back is performed by the suck-back mechanism 50. In the example shown in FIG. 5 , the flow rate sensor 56 is disposed on the second pipe 53 between the first bent portion 522 and the orifice 532. The flow rate sensor 56 measures the instantaneous flow rate of the processing liquid flowing downward through the second pipe 53. For example, an ultrasonic flow rate sensor is used as the flow rate sensor 56.

[0042] The flow rate sensor 56 is, for example, an integrated flow rate sensor capable of measuring the instantaneous flow rate and integrated flow rate of the treatment liquid. The flow rate sensor 56 measures the instantaneous flow rate of the treatment liquid at its installation position, and based on the measurement result (i.e., by integrating the measurement result of the instantaneous flow rate), determines the integrated flow rate of the treatment liquid that has passed through the installation position since a predetermined measurement start timing (i.e., the integrated flow rate of the treatment liquid discharged from the first pipe 52 to the second pipe 53; hereinafter, also referred to as the "integrated discharge flow rate").

[0043] The timing for starting measurement of the integrated discharge flow rate is the timing at which the suck-back of the processing liquid is considered to have substantially started, and is appropriately set by the user of the substrate processing apparatus 1, etc. For example, the calculation of the integrated discharge flow rate is performed in parallel with the closing of the first valve 521. Here, "closing the first valve 521" may mean, for example, "transmission of a close command signal from the control unit 8 to the first valve 521," or, if an opening / closing sensor is provided to monitor the opening / closing operation of the first valve 521, may mean "receiving a closing start signal or a closing completion signal for the first valve 521 from the opening / closing sensor." Alternatively, "closing the first valve 521" may mean another state in which the first valve 521 is considered to be substantially closed.

[0044] In addition, in cases where the discharge of the processing liquid from the first pipe 52 to the second pipe 53 during suckback begins a short time after the above-mentioned "closing of the first valve 521," the calculation of the cumulative discharge flow rate may begin a predetermined time after the "closing of the first valve 521."

[0045] Alternatively, when suck back is performed and second valve 531 is opened before first valve 521 is closed, calculation of the integrated discharge flow rate may be started in parallel with the opening of second valve 531. Here, "opening of second valve 531" may mean, for example, "transmission of an open command signal from control unit 8 to second valve 531," or, if an open / close sensor that monitors the opening and closing operation of second valve 531 is provided, may mean "receiving an opening start signal or an opening completion signal for second valve 531 from the open / close sensor." Alternatively, "opening of second valve 531" may mean another state in which second valve 531 is considered to be substantially open.

[0046] The instantaneous flow rate and the integrated discharge flow rate acquired by the flow sensor 56 are transmitted to the control unit 8 (see FIG. 4). The flow sensor 56 continuously acquires and transmits the instantaneous flow rate and the integrated discharge flow rate while the suck-back is being performed. The control unit 8 compares the integrated discharge flow rate with a predetermined suck-back threshold pre-stored in the memory unit 801. When the integrated discharge flow rate gradually increases and reaches the suck-back threshold, the valve control unit 802 closes the second valve 531 to stop the suck-back. As a result, a predetermined volume of the processing liquid is sucked back, and the liquid level of the processing liquid is positioned at a predetermined position in the nozzle 51 or the first pipe 52. In addition, in parallel with the stop of the suck-back, the acquisition of the integrated discharge flow rate by the flow sensor 56 is also stopped. In other words, the timing when the integrated discharge flow rate reaches the suck-back threshold is the timing when measurement of the integrated discharge flow rate ends. The flow sensor 56 resets the measured value of the integrated discharge flow rate to zero.

[0047] The flow rate sensor 56 may be disposed on the second pipe 53 between the orifice 532 and the second valve 531, or between the second valve 531 and the drain box 55.

[0048] Alternatively, the flow rate sensor 56 may be disposed on the first pipe 52 between the nozzle 51 and the first bent portion 522. In this case, the flow rate sensor 56 may be used to measure the instantaneous flow rate of the processing liquid when it is supplied to the substrate 9, in addition to measuring the instantaneous flow rate and the integrated discharge flow rate of the processing liquid during suckback. Specifically, while the processing liquid is being supplied from the processing liquid supply source 71 to the nozzle 51 and the substrate 9 is being processed (i.e., while the first valve 521 is open and the second valve 531 is closed), the flow rate sensor 56 continuously measures the instantaneous flow rate of the processing liquid being discharged from the nozzle 51 toward the substrate 9. Then, the valve control unit 802 (see FIG. 4 ) controls the opening degree of the first valve 521 and the like based on the measured instantaneous flow rate, thereby suitably maintaining the instantaneous flow rate of the processing liquid being discharged to the substrate 9 at a desired target flow rate. The suck-back state and the supply state of the processing liquid to the nozzle 51 are distinguished based on, for example, the open / close states of the first valve 521 and the second valve 531 controlled by the valve control unit 802.

[0049] Furthermore, if the flow rate sensor 56 disposed on the first pipe 52 between the nozzle 51 and the first bent portion 522 can detect not only the flow rate but also the flow direction of the treatment liquid, the suck-back period and the supply of the treatment liquid to the nozzle 51 may be distinguished from each other by the flow direction of the treatment liquid detected by the flow rate sensor 56. In this case, the timing at which the flow direction of the treatment liquid detected by the flow rate sensor 56 changes from the direction from the first bent portion 522 to the nozzle 51 to the direction from the nozzle 51 to the first bent portion 522 marks the transition from the supply of the treatment liquid to the nozzle 51 to the suck-back period. Therefore, calculation of the integrated discharge flow rate is started in parallel with the change in the flow direction of the treatment liquid detected by the flow rate sensor 56.

[0050] The flow rate sensor 56 only needs to be able to measure the instantaneous flow rate of the processing liquid, and does not necessarily have to have the function of calculating the cumulative flow rate of the processing liquid. When the flow rate sensor 56 measures only the instantaneous flow rate, the measured instantaneous flow rate is continuously transmitted to the control unit 8 (see FIG. 4) and stored in the memory unit 801. Then, the measurement values ​​of the instantaneous flow rate stored in the memory unit 801 are integrated by the calculation unit 803 from the measurement start timing described above, thereby calculating the cumulative discharge flow rate.

[0051] As described above, the substrate processing apparatus 1 may be capable of supplying a plurality of types of processing liquid to the substrate 9. In this case, the storage unit 801 stores a plurality of suck-back thresholds corresponding to the plurality of types of processing liquid. The plurality of suck-back thresholds may be different from one another depending on the type of processing liquid, or may include the same value. This allows suck-back to be performed at a suck-back amount (i.e., the volume of processing liquid to be sucked back) appropriate for each processing liquid.

[0052] For example, the suck-back threshold corresponding to a processing liquid (e.g., an etching liquid such as SC-1) supplied to the nozzle 51 at a temperature higher than room temperature is higher than the suck-back threshold corresponding to a processing liquid supplied to the nozzle 51 at room temperature. In this way, for a high-temperature processing liquid, increasing the suck-back amount can reduce the amount of processing liquid (hereinafter also referred to as "residual processing liquid") remaining in the nozzle 51 and the first pipe 52, or only in the first pipe 52, after suck-back. Since the temperature of the residual processing liquid decreases over time, when processing the substrate 9 after suck-back, the residual processing liquid may mix with the high-temperature processing liquid delivered from the processing liquid supply source 71, causing the temperature of the processing liquid supplied to the substrate 9 to drop below the predetermined processing temperature. Therefore, by reducing the amount of residual processing liquid, the temperature drop of the processing liquid supplied to the substrate 9 after suck-back is suppressed.

[0053] As shown in FIGS. 6 and 7 , the substrate processing apparatus 1 may be provided with an imaging unit 6 that captures an image of the nozzle 51, and the control unit 8 may include an image monitoring unit 804. The imaging unit 6 captures an image of the tip of the nozzle 51 (i.e., the vicinity of the discharge port) and sends the captured image to the control unit 8. The imaging unit 6 is, for example, a charge-coupled device (CCD) camera or a complementary metal oxide semiconductor (CMOS) camera. The image monitoring unit 804 determines whether the nozzle 51 is discharging the processing liquid based on the image of the tip of the nozzle 51 captured by the imaging unit 6 (i.e., the output from the imaging unit 6). In the control unit 8, for example, images of the nozzle 51 discharging the processing liquid and images of the nozzle 51 when the discharge of the processing liquid has stopped are stored in advance in the storage unit 801 as a reference image group, and the image monitoring unit 804 compares the output from the imaging unit 6 with the reference image group using a known image analysis method to determine whether the nozzle 51 is discharging the processing liquid. In this case, calculation of the integrated discharge flow rate by the flow rate sensor 56 (see FIG. 5) starts, for example, when the image monitoring unit 804 determines that the discharge of the processing liquid from the nozzle 51 has stopped.

[0054] Next, a substrate processing apparatus 1a according to a second embodiment of the present invention will be described. Fig. 8 is a block diagram showing a processing liquid supply unit 5a of the substrate processing apparatus 1a, and corresponds to Fig. 5 described above. The configuration of the substrate processing apparatus 1a is the same as that of the substrate processing apparatus 1 shown in Fig. 1, except that the processing liquid supply unit 5 shown in Fig. 5 is replaced with a processing liquid supply unit 5a having a structure different from that of the processing liquid supply unit 5. In the following description, the same components of the substrate processing apparatus 1a as those of the substrate processing apparatus 1 will be denoted by the same reference numerals.

[0055] As shown in FIG. 8, the processing liquid supply unit 5a includes the nozzle 51 described above, a first pipe 52a, and a first valve 521a. As described above, the nozzle 51 ejects the processing liquid toward the substrate 9. The first pipe 52a connects the processing liquid supply source 71 and the nozzle 51. In the example shown in FIG. 8, the first pipe 52a has a slightly different shape from the first pipe 52 shown in FIG. 5. The first valve 521a is disposed on the first pipe 52a and is controlled by the valve control unit 802 (see FIG. 4). The processing liquid supply unit 5a also includes the flow rate sensor 56 described above.

[0056] In the processing liquid supply unit 5a, a suck-back mechanism 50a, which has a different structure from the above-described suck-back mechanism 50, is connected to the first pipe 52a between the nozzle 51 and the first valve 521a. The suck-back mechanism 50a is an ejector-type suck-back mechanism. The suck-back mechanism 50a includes a second pipe 53a, a second valve 531a, a needle valve 533a, a third pipe 54a, a third valve 541a, and a check valve 542a. The second pipe 53a branches off from the first pipe 52a between the nozzle 51 and the first valve 521 and processing liquid supply source 71. The end of the second pipe 53a opposite to the first pipe 52a side is connected to the third pipe 54a. The second valve 531a and the needle valve 533a are disposed on the second pipe 53a. The second valve 531a is controlled by a valve control unit 802.

[0057] One end of the third pipe 54a is connected to the gas supply source 72, and the other end is connected to the drain box 55a. The third valve 541a and the check valve 542a are disposed on the third pipe 54a. The third valve 541a is controlled by the valve control unit 802. The second pipe 53a is connected to the third pipe 54a downstream of the third valve 541a (i.e., between the third valve 541a and the drain box 55a).

[0058] In the processing liquid supply unit 5a, the second valve 531a and the third valve 541a are closed and the first valve 521a is opened under the control of the valve control unit 802, whereby the processing liquid used to process the substrate 9 is supplied from the processing liquid supply source 71 to the nozzle 51 via the first pipe 52a and is discharged from the tip of the nozzle 51 (i.e., the lower end of the nozzle 51) onto the upper surface 91 of the substrate 9. Then, the valve control unit 802 closes the first valve 521a, whereby the discharge of the processing liquid from the nozzle 51 is stopped.

[0059] In the processing liquid supply unit 5a, the third valve 541a is opened under the control of the valve control unit 802, whereby gas (e.g., compressed air) is supplied from the gas supply source 72 to the third pipe 54a and flows at a relatively high speed into the drain box 55a. As a result, negative pressure is generated in the second pipe 53a near the connection 535a between the second pipe 53a and the third pipe 54a. Then, under the control of the valve control unit 802, the first valve 521a is closed and the second valve 531a is opened, whereby the processing liquid in the second pipe 53a flows into the third pipe 54a due to the negative pressure and flows into the drain box 55a together with the gas. As a result, the processing liquid in the first pipe 52a is discharged into the second pipe 53a, and the processing liquid in the nozzle 51 is sucked back.

[0060] When suck-back is performed, the liquid level of the processing liquid (i.e., the interface between the processing liquid and the surrounding atmosphere) moves from the tip of the nozzle 51 toward the first pipe 52a. When suck-back is started, the second valve 531a may be opened after the first valve 521a is closed, or the second valve 531a may be opened slightly before the first valve 521a is closed, or the second valve 531a may be opened approximately simultaneously with the closure of the first valve 521a. Thereafter, the valve control unit 802 closes the second valve 531a and the third valve 541a, thereby stopping the suck-back of the processing liquid.

[0061] The flow rate sensor 56 measures the instantaneous flow rate (i.e., suck-back speed) of the treatment liquid discharged from the first pipe 52 to the second pipe 53 when the suck-back mechanism 50a performs suck-back. In the example shown in FIG. 8 , the flow rate sensor 56 is disposed on the second pipe 53a, between the second valve 531a and the connection 534a between the second pipe 53a and the first pipe 52a. The flow rate sensor 56 measures the instantaneous flow rate of the treatment liquid flowing through the second pipe 53a toward the third pipe 54a. As described above, the flow rate sensor 56 can be an ultrasonic integrated flow rate sensor capable of measuring the instantaneous flow rate and integrated discharge flow rate of the treatment liquid (i.e., the integrated flow rate of the treatment liquid discharged from the first pipe 52a to the second pipe 53a).

[0062] The flow rate sensor 56 may be disposed on the second pipe 53a between the second valve 531a and a connection 535a between the second pipe 53a and the third pipe 54a. The flow rate sensor 56 may be disposed on the third pipe 54a between the drain box 55a and a connection 535a between the second pipe 53a and the third pipe 54a.

[0063] Alternatively, the flow rate sensor 56 may be disposed on the first pipe 52a between the nozzle 51 and a connection portion 534a between the first pipe 52a and the second pipe 53a. In this case, the flow rate sensor 56 may be used to measure the instantaneous flow rate of the processing liquid when it is supplied to the substrate 9, in addition to measuring the instantaneous flow rate and the integrated discharge flow rate of the processing liquid during suckback. Specifically, while the processing liquid is being supplied from the processing liquid supply source 71 to the nozzle 51 to process the substrate 9 (i.e., while the first valve 521a is open and the second valve 531a is closed), the flow rate sensor 56 continuously measures the instantaneous flow rate of the processing liquid discharged from the nozzle 51 toward the substrate 9. Then, the valve control unit 802 (see FIG. 4) controls the opening degree of the first valve 521a and the like based on the measured instantaneous flow rate, thereby suitably maintaining the instantaneous flow rate of the processing liquid discharged to the substrate 9 at a desired target flow rate. The suck-back state and the supply state of the processing liquid to the nozzle 51 are distinguished based on, for example, the open / close states of the first valve 521a, the second valve 531a, and the third valve 541a controlled by the valve control unit 802.

[0064] The timing at which the flow rate sensor 56 starts calculating the integrated discharge flow rate (i.e., the measurement start timing) may be set in various ways to correspond to the timing at which the suck-back of the processing liquid is considered to have substantially started, as described above. The flow rate sensor 56 continuously acquires the instantaneous flow rate and the integrated discharge flow rate and transmits the measured values ​​to the control unit 8 while the suck-back is being performed. The control unit 8 compares the integrated discharge flow rate with a suck-back threshold. When the integrated discharge flow rate reaches the suck-back threshold, the valve control unit 802 closes the second valve 531a and the third valve 541a to stop the suck-back. As a result, a predetermined volume of the processing liquid is sucked back, and the liquid level of the processing liquid is positioned at a predetermined position in the nozzle 51 or the first pipe 52a. The integrated discharge flow rate may be calculated by the calculation unit 803 (see FIG. 4 ) of the control unit 8 based on the instantaneous flow rate measured by the flow rate sensor 56, as described above.

[0065] As described above, the substrate processing apparatus 1, 1a for processing a substrate 9 includes the nozzle 51, the first pipes 52, 52a, the first valves 521, 521a, the second pipes 53, 53a, the second valves 531, 531a, the flow rate sensor 56, and the valve control unit 802. The nozzle 51 discharges a processing liquid to be supplied to the substrate 9. The first pipes 52, 52a connect the processing liquid supply source 71 to the nozzle 51. The first valves 521, 521a are disposed on the first pipes 52, 52a. The second pipes 53, 53a branch off from the first pipes 52, 52a between the nozzle 51 and the processing liquid supply source 71. The second valves 531, 531a are disposed on the second pipes 53, 53a. The flow rate sensor 56 measures the instantaneous flow rate of the processing liquid discharged from the first pipes 52, 52a to the second pipes 53, 53a. The valve control unit 802 controls the first valves 521 and 521a and the second valves 531 and 531a.

[0066] In the substrate processing apparatus 1, 1a, the processing liquid is supplied from the processing liquid supply source 71 to the nozzle 51 with the first valves 521, 521a open and the second valves 531, 531a closed. Furthermore, with the first valves 521, 521a closed and the second valves 531, 531a open, the processing liquid in the first pipes 52, 52a is discharged to the second pipes 53, 53a, thereby sucking back the processing liquid from the nozzle 51. Then, based on the measurement results of the flow rate sensor 56, an integrated discharge flow rate, which is the integrated flow rate of the processing liquid discharged from the first pipes 52, 52a to the second pipes 53, 53a, is calculated. The valve control unit 802 closes the second valves 531, 531a when the integrated discharge flow rate reaches a predetermined suckback threshold.

[0067] In this way, in the substrate processing apparatus 1, 1a, the integrated discharge flow rate of the processing liquid from the start of suck-back is measured, and an amount of processing liquid equal to a predetermined suck-back threshold is sucked back, thereby enabling the liquid level of the processing liquid after suck-back to be accurately positioned at a desired position. As a result, the amount of processing liquid supplied to the substrate 9 after suck-back (e.g., the amount of processing liquid supplied to the next substrate 9) can be accurately adjusted to a desired amount. Therefore, the quality of processing of the substrate 9 can be improved.

[0068] As described above, it is preferable that the calculation of the integrated discharge flow rate be started in parallel with the closing of the first valves 521 and 521a. This allows the start of the calculation of the integrated discharge flow rate to coincide with the actual start timing of the suck-back. As a result, the integrated discharge flow rate can be calculated with high accuracy.

[0069] As described above, it is also preferable that the calculation of the integrated discharge flow rate be started a predetermined time after the first valves 521, 521 a are closed. This makes it possible to accurately calculate the integrated discharge flow rate even if the movement of the processing liquid (i.e., movement in the direction away from the tip of the nozzle 51) starts a little later than the closure of the first valves 521, 521 a.

[0070] As described above, when sucking back, it is also preferable to open the second valves 531, 531a before closing the first valves 521, 521a. This makes it possible to effectively prevent the occurrence of the water hammer phenomenon. In this case, it is also preferable to start calculating the integrated discharge flow rate in parallel with the opening of the second valves 531, 531a. This makes it possible to accurately calculate the integrated discharge flow rate.

[0071] As described above, it is preferable that the substrate processing apparatus 1 further includes the imaging unit 6 and the image monitoring unit 804. The imaging unit 6 captures an image of the nozzle 51. The image monitoring unit 804 determines whether or not the processing liquid is being discharged from the nozzle 51 based on the output from the imaging unit 6. It is preferable that the calculation of the integrated discharge flow rate is started when the image monitoring unit 804 determines that the processing liquid has stopped being discharged from the nozzle 51. This allows the start of calculation of the integrated discharge flow rate to be synchronized with the actual start timing of the suck-back. As a result, the integrated discharge flow rate can be calculated with high accuracy. The same applies to the substrate processing apparatus 1a.

[0072] As described above, the flow rate sensor 56 is preferably disposed on the second pipe 53, 53a. In the second pipe 53, 53a, substantially no flow of the processing liquid occurs when the processing liquid is supplied to the substrate 9, but a flow of the processing liquid occurs only during suck-back. Therefore, by disposing the flow rate sensor 56 on the second pipe 53, 53a, the integrated discharge flow rate during suck-back can be calculated with high accuracy. Note that in the substrate processing apparatus 1a, a flow of the processing liquid also occurs in the third pipe 54a only during suck-back. However, because a mixed fluid of the processing liquid and a gas such as compressed air flows in the third pipe 54a, it is more preferable to dispose the flow rate sensor 56 on the second pipe 53a from the viewpoint of accurately calculating the integrated discharge flow rate.

[0073] As described above, it is also preferable that flow rate sensor 56 be disposed on first pipe 52, 52a. In this case, it is preferable that flow rate sensor 56 measure the supply flow rate of the processing liquid when the processing liquid is supplied from processing liquid supply source 71 to nozzle 51. In this way, flow rate sensor 56, which is used to measure the instantaneous flow rate and integrated discharge flow rate of the processing liquid during suck-back, is also used to measure the flow rate when the processing liquid is supplied to nozzle 51 (i.e., when the processing liquid is supplied to substrate 9), thereby simplifying the structure of substrate processing apparatus 1, 1a compared to when separate flow rate sensors are provided for each measurement.

[0074] As described above, the substrate processing apparatus 1, 1a preferably further includes a storage unit 801 that stores a plurality of suck-back thresholds corresponding to a plurality of types of processing liquid, respectively, so that suck-back can be performed with an appropriate suck-back amount according to the type of processing liquid.

[0075] More preferably, the suck-back threshold corresponding to the processing liquid supplied at a temperature higher than room temperature is greater than the suck-back threshold corresponding to the processing liquid supplied at room temperature. In this way, when the processing liquid is supplied at a temperature higher than room temperature, by increasing the suck-back amount (i.e., reducing the amount of residual processing liquid), it is possible to prevent the cooled residual processing liquid from mixing with the high-temperature processing liquid when processing the substrate 9 after the suck-back. As a result, it is possible to prevent an unintended decrease in temperature of the processing liquid supplied to the substrate 9.

[0076] The above-described substrate processing apparatus 1, 1a can be modified in various ways.

[0077] For example, in the substrate processing apparatus 1, 1a, the timing at which calculation of the cumulative discharge flow rate begins is not necessarily limited to that described above, and may be any timing as long as it is considered that the suck-back of the processing liquid has essentially begun.

[0078] The flow rate sensor 56 is not limited to an ultrasonic flow rate sensor, and may be another type of flow rate sensor (for example, an electromagnetic flow rate sensor). Furthermore, the flow rate sensor 56 does not necessarily have to be a type that can detect the flow direction of the processing liquid.

[0079] In the substrate processing apparatuses 1 and 1a, instead of the siphon-type suck-back mechanism 50 and the ejector-type suck-back mechanism 50a, a suck-back mechanism having another structure may be provided.

[0080] The above-described substrate processing apparatus 1, 1a may be used to process glass substrates used in flat panel displays such as liquid crystal displays or organic EL (Electro Luminescence) displays, or glass substrates used in other displays, in addition to semiconductor substrates. The above-described substrate processing apparatus 1, 1a may also be used to process substrates for optical disks, magnetic disks, magneto-optical disks, photomasks, ceramic substrates, solar cell substrates, etc.

[0081] The configurations in the above-described embodiment and each modification may be combined as appropriate as long as they are not mutually contradictory. [Explanation of symbols]

[0082] 1, 1a Substrate processing equipment 6. Imaging unit 9 Substrate 51 nozzles 52,52a First piping 53,53a Second piping 56 Flow sensor 71 Processing liquid supply source 521,521a First valve 531,531a Second valve 801 Storage section 802 Valve control section 804 Image Monitoring Department

Claims

1. A substrate processing apparatus for processing a substrate, a nozzle that discharges a processing liquid to be supplied to the substrate; a first pipe connecting a processing liquid supply source and the nozzle; a first valve disposed on the first pipe; a second pipe branching from the first pipe between the nozzle and the processing liquid supply source; a second valve disposed on the second pipe; a flow rate sensor for measuring an instantaneous flow rate of the treatment liquid discharged from the first pipe to the second pipe; a valve control unit that controls the first valve and the second valve; Equipped with supplying a processing liquid from the processing liquid supply source to the nozzle while the first valve is open and the second valve is closed; with the first valve closed and the second valve open, the processing liquid in the first pipe is discharged to the second pipe, thereby sucking back the processing liquid in the nozzle; an integrated discharge flow rate, which is an integrated flow rate of the treatment liquid discharged from the first pipe to the second pipe, is calculated based on the measurement result by the flow rate sensor; The substrate processing apparatus, wherein the valve control unit closes the second valve when the integrated discharge flow rate reaches a predetermined suck-back threshold value.

2. The substrate processing apparatus according to claim 1 , The substrate processing apparatus according to claim 1, wherein the calculation of the integrated discharge flow rate is started in parallel with the closing of the first valve.

3. The substrate processing apparatus according to claim 1 , The substrate processing apparatus according to claim 1, wherein the calculation of the integrated discharge flow rate is started a predetermined time after the first valve is closed.

4. The substrate processing apparatus according to claim 1 , When sucking back, the second valve is opened before the first valve is closed, The substrate processing apparatus according to claim 1, wherein the calculation of the integrated discharge flow rate is started in parallel with the opening of the second valve.

5. The substrate processing apparatus according to claim 1 , an imaging unit that images the nozzle; an image monitoring unit that determines whether or not the processing liquid is being ejected from the nozzle based on an output from the imaging unit; Furthermore, The substrate processing apparatus according to claim 1, wherein the calculation of the integrated discharge flow rate is started when the image monitoring unit determines that the discharge of the processing liquid from the nozzle has stopped.

6. 6. The substrate processing apparatus according to claim 1, The substrate processing apparatus is characterized in that the flow rate sensor is disposed on the second pipe.

7. 6. The substrate processing apparatus according to claim 1, the flow rate sensor is disposed on the first pipe; a flow rate sensor for measuring a supply flow rate of the processing liquid when the processing liquid is supplied from the processing liquid supply source to the nozzle;

8. 8. The substrate processing apparatus according to claim 1, The substrate processing apparatus further comprises a storage unit that stores a plurality of suck-back thresholds corresponding to a plurality of types of processing liquids.

9. 9. The substrate processing apparatus according to claim 8, 10. A substrate processing apparatus, wherein the suck-back threshold value corresponding to a processing liquid supplied at a temperature higher than room temperature is greater than the suck-back threshold value corresponding to a processing liquid supplied at room temperature.

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