JP7725361B2 - Discharge pressure evaluation method, discharge pressure evaluation program, recording medium, and substrate processing apparatus - Google Patents

Description

This invention relates to a technology for ejecting a treatment liquid from a nozzle by applying an ejection pressure to the treatment liquid. Note that examples of objects onto which the treatment liquid can be ejected from a nozzle include semiconductor substrates, photomask substrates, liquid crystal display substrates, organic EL display substrates, plasma display substrates, FED (Field Emission Display) substrates, optical disk substrates, magnetic disk substrates, and magneto-optical disk substrates.

As shown in Patent Documents 1 and 2, when processing liquid ejected from a nozzle is applied to a substrate, the ejection pressure applied to the processing liquid significantly affects the thickness of the processing liquid applied to the substrate. Therefore, in Patent Document 1, the waveform of the ejection pressure is divided into multiple sections, and whether the ejection pressure is within an acceptable range is evaluated based on the slope of the waveform in each section. Furthermore, in Patent Document 2, parameters related to the ejection pressure are optimized for each region, such as the rise region and steady ejection region.

JP 2011-005465 A Japanese Patent Application Laid-Open No. 2020-040046

However, the above technology evaluates the period from the start to the end of the discharge of the treatment liquid from the nozzle in divided segments. As a result, the appropriateness of the discharge pressure over the entire period that affects the thickness of the treatment liquid applied to the substrate is not reflected in the evaluation of the discharge pressure, and it may not necessarily be said that the discharge pressure is being evaluated appropriately. In particular, the main period from the start of discharge of the treatment liquid from the nozzle, through the rise in the discharge pressure to a predetermined pressure, to the start of the decrease in the discharge pressure from that predetermined pressure is considered to be important. Therefore, while it is necessary to reflect the evaluation of the discharge pressure over the entire period that includes at least this main period, this technology was insufficient in this respect.

This invention was developed in consideration of the above-mentioned problems, and aims to make it possible to reflect in the evaluation of the discharge pressure the appropriateness of the discharge pressure over the entire period that affects the thickness of the processing liquid applied to the substrate.

The discharge pressure evaluation method according to the present invention includes the steps of measuring the discharge pressure during an evaluation period that includes at least the main period from when a discharge device applies discharge pressure to a treatment liquid and discharges the treatment liquid from a nozzle, through which the discharge pressure rises to a predetermined pressure, until the discharge pressure starts to decrease from the predetermined pressure, by a discharge device that applies discharge pressure to the treatment liquid and discharges the treatment liquid from a nozzle; extracting, as an overall characteristic quantity, a characteristic quantity possessed by the time change in the discharge pressure throughout the evaluation period; and evaluating the time change in the discharge pressure based on the overall characteristic quantity.

The discharge pressure evaluation program of the present invention causes a computer to execute the following steps: a step of measuring the discharge pressure during an evaluation period that includes at least the main period from when a discharge device that applies discharge pressure to a treatment liquid to discharge the treatment liquid from a nozzle starts to when the discharge pressure increases to a predetermined pressure and then starts to decrease from the predetermined pressure; a step of extracting, as an overall characteristic quantity, a characteristic quantity possessed by the time change in the discharge pressure throughout the evaluation period; and a step of evaluating the time change in the discharge pressure based on the overall characteristic quantity.

The recording medium according to the present invention records the above-mentioned discharge pressure evaluation program in a computer-readable manner.

The substrate processing apparatus according to the present invention includes a nozzle, a pressure applying unit that applies a discharge pressure to the processing liquid to cause the nozzle to discharge the processing liquid, a measurement unit that measures the discharge pressure, and a control unit that acquires the discharge pressure measured by the measurement unit during an evaluation period that includes at least the main period from when the processing liquid starts to be discharged from the nozzle, through when the discharge pressure increases to a predetermined pressure, until when the discharge pressure starts to decrease from the predetermined pressure. The control unit extracts a characteristic quantity possessed by the time change in the discharge pressure throughout the evaluation period as an overall characteristic quantity, and evaluates the time change in the discharge pressure based on the overall characteristic quantity.

In the present invention (discharge pressure evaluation method, discharge pressure evaluation program, recording medium, and substrate processing apparatus) configured in this manner, the discharge pressure is measured during an evaluation period that includes at least the main period from when the discharge of processing liquid from the nozzle begins, through the rise in the discharge pressure to a predetermined pressure, to when the discharge pressure begins to decrease from the predetermined pressure. A feature quantity possessed by the time change in the discharge pressure throughout the evaluation period is then extracted as an overall feature quantity, and the time change in the discharge pressure is evaluated based on the overall feature quantity. This makes it possible to reflect in the evaluation of the discharge pressure the appropriateness of the discharge pressure throughout the period that affects the thickness of the processing liquid applied to the substrate (in other words, the evaluation period).

The discharge pressure evaluation method may also be configured so that the evaluation period is a main period, and a main feature quantity, which is a feature quantity possessed by the time change in discharge pressure throughout the main period, is extracted as an overall feature quantity. With this configuration, when the main period has a particularly large impact on the thickness of the processing liquid applied to the substrate (in other words, when the impact of the period after the main period is small), it is possible to reflect the appropriateness of the discharge pressure throughout the main period in the evaluation of the discharge pressure.

The discharge pressure evaluation method may also be configured so that the main characteristic quantity indicates the difference between a main approximate waveform that approximates the time change in discharge pressure over the entire main period and the time change in discharge pressure over the entire main period. With this configuration, the discharge pressure over the entire main period can be appropriately evaluated based on the approximate waveform of the time change in discharge pressure over the entire main period.

The discharge pressure evaluation method may also be configured so that the main approximate waveform includes a rising approximate line that linearly increases over time from the discharge start pressure to a steady-state pressure greater than the discharge start pressure, which is a linear approximation of the time change in discharge pressure that increases over time after discharge of the treatment liquid from the nozzle begins; a start approximate line that is located between the start of discharge of the treatment liquid from the nozzle and the rising approximate line and indicates the discharge start pressure; and a steady-state line that is located between the time when the rising approximate line reaches the steady-state pressure and the end of the main period and indicates the steady-state pressure. With this configuration, the time change in discharge pressure over the entire main period can be approximated, allowing the discharge pressure over the entire period to be appropriately evaluated.

The ejection pressure evaluation method may also be configured so that the evaluation period is a first period from the start of ejection of the treatment liquid from the nozzle to the end of ejection of the treatment liquid from the nozzle, and a first feature quantity, which is a feature quantity possessed by the temporal change in the ejection pressure throughout the first period, is extracted as an overall feature quantity. With this configuration, if the ejection pressure affects the thickness of the treatment liquid applied to the substrate throughout the first period from the start of ejection of the treatment liquid from the nozzle to the end of ejection of the treatment liquid from the nozzle, the appropriateness of the ejection pressure throughout the first period can be reflected in the evaluation of the ejection pressure.

The discharge pressure evaluation method may also be configured so that the first characteristic amount indicates the difference between a first approximate waveform that approximates the change in discharge pressure over time throughout the first period, and the change in discharge pressure over time throughout the first period. With this configuration, the discharge pressure over the entire period from the start to the end of discharge of the treatment liquid from the nozzle can be appropriately evaluated based on the approximate waveform of the change in discharge pressure over time throughout the period.

The discharge pressure evaluation method may also be configured to include: a rising approximation line that linearly increases over time from the discharge start pressure to a steady-state pressure greater than the discharge start pressure by linearly approximating the time change in the discharge pressure that increases over time after the start of discharge of the treatment liquid from the nozzle; a start approximation line that is located between the start of discharge of the treatment liquid from the nozzle and the rising approximation line and indicates the discharge start pressure; a falling approximation line that linearly decreases over time from the steady-state pressure to a discharge end pressure that is smaller than the steady-state pressure by linearly approximating the time change in the discharge pressure that decreases over time before the end of discharge of the treatment liquid from the nozzle; an end approximation line that is located between the falling approximation line and the end of discharge of the treatment liquid from the nozzle and indicates the discharge end pressure; and a steady-state line that connects the rising approximation line and the falling approximation line and indicates the steady-state pressure. With this configuration, the time change in the discharge pressure over the entire period from the start to the end of discharge of the treatment liquid from the nozzle is approximated by a trapezoidal waveform, allowing the discharge pressure over that entire period to be appropriately evaluated.

The discharge pressure evaluation method may also be configured to further include a step of extracting, as a second feature, a feature quantity possessed by the change in discharge pressure over time during a second period of the evaluation period that is shorter than the evaluation period, and to evaluate the change in discharge pressure over time based on the overall feature quantity and the second feature quantity. With this configuration, the discharge pressure can be evaluated with high accuracy based on the change in discharge pressure over time during both the entire period from the start to the end of discharge of the treatment liquid from the nozzle and a period shorter than that period.

The discharge pressure evaluation method may also be configured so that a predetermined initial rise period from the start of discharge of treatment liquid from the nozzle is set as the second period, the discharge pressure increases over time throughout the initial rise period, and a feature value indicating the difference between the regression curve of the time change in discharge pressure during the initial rise period and the time change in discharge pressure during the initial rise period is extracted as the second feature value. With this configuration, the discharge pressure can be evaluated by taking into account the time change in discharge pressure immediately after the start of discharge of treatment liquid from the nozzle.

The discharge pressure evaluation method may also be configured so that the rise period from when the treatment liquid starts to be discharged from the nozzle until the discharge pressure increases to a predetermined pressure is set as the second period. In this configuration, the discharge pressure can be evaluated taking into account the change in discharge pressure over time during the rise period.

Specifically, the discharge pressure evaluation method may be configured so that the length of the rise period is extracted as the second feature. With this configuration, the discharge pressure can be evaluated taking into account the speed at which the discharge pressure rises.

The discharge pressure evaluation method may also be configured so that the number of times the first derivative of the time change in the discharge pressure during the rise period crosses a predetermined threshold is extracted as the second feature. With this configuration, the discharge pressure can be evaluated taking into account the smoothness of the time change in the discharge pressure during the rise period.

The discharge pressure evaluation method may also be configured so that the number of times the absolute value of the second-order derivative of the time change in the discharge pressure during the rise period crosses a predetermined threshold is extracted as the second feature value. With this configuration, the discharge pressure can be evaluated taking into account the smoothness of the time change in the discharge pressure during the rise period.

The discharge pressure evaluation method may also be configured so that the ratio of the time during the rise period during which the second derivative of the time change in the discharge pressure exceeds a predetermined positive threshold to the time during which the second derivative of the time change in the discharge pressure falls below a predetermined negative threshold having the same absolute value as the positive threshold is extracted as the second feature value. With this configuration, the discharge pressure can be evaluated taking into account the difference in the time change in the discharge pressure between the beginning and end of the rise period.

Also, the discharge pressure evaluation method may be configured so that a predetermined rise end period until the discharge pressure increases to a predetermined pressure is set as the second period, and a feature value indicating the difference between a rise end approximation waveform, which approximates the time change in discharge pressure during the rise end period, and the time change in discharge pressure during the rise end period is extracted as the second feature value. The rise end approximation waveform overlaps an approximation curve obtained by linearly approximating the time change in discharge pressure that increases over time in a pressure range smaller than the predetermined pressure, and includes a rise end approximation line that linearly increases over time to a steady pressure, which is the average value of the time change in discharge pressure during the steady period after the rise end period, and an extension line indicating the steady pressure, extending from the rise end approximation line to the end of the rise end period. With this configuration, the discharge pressure can be evaluated taking into account the degree of stall in the discharge pressure at the end of the rise period.

The discharge pressure evaluation method may also be configured so that the initial oscillation period from when the discharge pressure reaches its maximum value to when the second derivative of the time change in the discharge pressure crosses zero twice is set as the second period, and the difference between the maximum discharge pressure and the smaller of the minimum value of the discharge pressure during the initial oscillation period and the average value of the discharge pressure during a predetermined steady period after the initial oscillation period is extracted as the second characteristic amount. With this configuration, the discharge pressure can be evaluated taking into account the overshoot of the discharge pressure.

The discharge pressure evaluation method may also be configured so that a predetermined transition period from the point at which the discharge pressure exceeds the predetermined pressure is set as the second period, and a feature value indicating the difference between the discharge pressure during the transition period and the average value of the discharge pressure during a predetermined steady period after the transition period is extracted as the second feature value. With this configuration, the discharge pressure can be evaluated taking into account the stability of the discharge pressure after it reaches the predetermined pressure.

The discharge pressure evaluation method may also be configured so that the constant pressure period from when the discharge pressure exceeds a predetermined pressure to when the discharge pressure begins to decrease toward the end of discharge of the treatment liquid from the nozzle is set as the second period, and a feature value indicating the difference between the maximum and minimum values of the discharge pressure during the constant pressure period is extracted as the second feature value. With this configuration, the discharge pressure can be evaluated taking into account the stability of the discharge pressure during the constant pressure period.

As described above, according to the present invention, the appropriateness of the ejection pressure throughout the entire period from the start to the end of the ejection of treatment liquid from the nozzle can be reflected in the evaluation of the ejection pressure.

FIG. 1 is a diagram showing a schematic view of the overall configuration of a coating apparatus which is an embodiment of a substrate processing apparatus according to the present invention. FIG. 2 is a diagram showing the configuration of a coating liquid supply mechanism. FIG. 2 is a block diagram showing an example of the configuration of a control unit. 10 is a flowchart showing an example of a discharge pressure evaluation method executed based on a discharge pressure evaluation program. 5A and 5B are diagrams for explaining periods used in evaluating the discharge pressure. FIG. 6 is a diagram showing an example of a calculation performed by a pressure evaluation unit in response to a change in discharge pressure over time. FIG. 10 is a diagram for explaining evaluation items for evaluating the change over time in the discharge pressure based on the feature amount Fv1. FIG. 10 is a diagram for explaining evaluation items for evaluating the change over time in the discharge pressure based on the feature amount Fv2. FIG. 10 is a diagram for explaining evaluation items for evaluating the change over time in the discharge pressure based on the feature amount Fv3. FIG. 10 is a diagram for explaining evaluation items for evaluating the change over time in the discharge pressure based on the feature amount Fv4. FIG. 10 is a diagram showing an example of time change in ejection pressure that is determined to be inappropriate by evaluation based on the feature amount Fv4. FIG. 10 is a diagram for explaining evaluation items for evaluating the change over time in the discharge pressure based on the feature amount Fv5. FIG. 10 is a diagram showing an example of temporal change in ejection pressure that is determined to be inappropriate by evaluation based on the feature amount Fv5. FIG. 10 is a diagram for explaining evaluation items for evaluating the change over time in the discharge pressure based on the feature amount Fv6. FIG. 10 is a diagram for explaining evaluation items for evaluating the change over time in the discharge pressure based on the feature amount Fv7. FIG. 10 is a diagram for explaining evaluation items for evaluating the change over time in the discharge pressure based on the feature amount Fv8. FIG. 10 is a diagram for explaining an evaluation item for evaluating the change over time in the discharge pressure based on the feature amount Fv9. FIG. 10 is a diagram for explaining evaluation items for evaluating the change over time in the discharge pressure based on the feature amount Fv10. 10A and 10B are diagrams for explaining periods used in a modified example of the evaluation item of discharge pressure. 10A and 10B are diagrams for explaining a modified example of an evaluation item for evaluating a change over time in discharge pressure based on a feature amount Fv1_1.

Figure 1 is a schematic diagram showing the overall configuration of a coating apparatus, one embodiment of a substrate processing apparatus according to the present invention. This coating apparatus 1 is a slit coater that applies a coating liquid to the upper surface Sf of a substrate S transported in a horizontal position from the left-hand side to the right-hand side of Figure 1. To clarify the layout of each part of the apparatus in the following figures, the transport direction of the substrate S is referred to as the "X direction," the horizontal direction from the left-hand side to the right-hand side of Figure 1 is referred to as the "+X direction," and the opposite direction is referred to as the "-X direction." Furthermore, in the horizontal direction Y perpendicular to the X direction, the front side of the apparatus is referred to as the "-Y direction," and the rear side of the apparatus is referred to as the "+Y direction." Furthermore, the upward and downward directions in the vertical direction Z are referred to as the "+Z direction" and "-Z direction," respectively.

In the coating device 1, the input conveyor 100, input transfer section 2, floating stage section 3, output transfer section 4, and output conveyor 110 are arranged in close proximity in this order along the transport direction Dt (+X direction) of the substrate S. As described in detail below, these components form a transport path for the substrate S that extends in a substantially horizontal direction. Note that in the following description, when indicating positional relationships in relation to the transport direction Dt of the substrate S, the "upstream side in the transport direction Dt of the substrate S" may be abbreviated simply as the "upstream side," and the "downstream side in the transport direction Dt of the substrate S" may be abbreviated simply as the "downstream side." In this example, the (-X) side corresponds to the "upstream side" and the (+X) side corresponds to the "downstream side" relative to a certain reference position.

The substrate S to be processed is carried into the input conveyor 100 from the left side of Figure 1. The input conveyor 100 comprises a roller conveyor 101 and a rotation drive mechanism 102 that drives it to rotate. As the roller conveyor 101 rotates, the substrate S is transported downstream in a horizontal position, in the (+X) direction. The input transfer unit 2 comprises a roller conveyor 21 and a rotation/elevation drive mechanism 22 that drives it to rotate and elevates it. As the roller conveyor 21 rotates, the substrate S is further transported in the (+X) direction. As the roller conveyor 21 elevates, the position of the substrate S in the vertical direction Z is changed. By the input transfer unit 2 configured in this manner, the substrate S is transferred from the input conveyor 100 to the floating stage unit 3.

The floating stage unit 3 comprises a flat stage divided into three sections along the substrate transport direction Dt. Specifically, the floating stage unit 3 comprises an entrance floating stage 31, a coating stage 32, and an exit floating stage 33, with the upper surfaces of each stage forming part of the same plane. Furthermore, the floating stage unit 3 has a lift pin drive mechanism 34, a floating control mechanism 35, and an elevation drive mechanism 36. The lift pin drive mechanism 34 can raise and lower the lift pins provided on the entrance floating stage 31. The floating control mechanism 35 can supply compressed air to each stage of the floating stage unit 3 to float the substrate S. The elevation drive mechanism 36 can raise and lower the exit floating stage 33.

The upper surfaces of the entrance levitation stage 31 and the exit levitation stage 33 are each provided with a matrix of multiple nozzles that spray compressed air supplied by the levitation control mechanism 35, and the substrate S is levitated by the buoyancy imparted by the sprayed airflow. In this way, the lower surface Sb of the substrate S is supported in a horizontal position with the lower surface Sb spaced apart from the upper surface of the stage. The distance between the lower surface Sb of the substrate S and the upper surface of the stage, i.e., the levitation amount, can be, for example, 10 micrometers to 500 micrometers.

On the other hand, on the upper surface of the coating stage 32, nozzle holes for ejecting compressed air and suction holes for sucking air between the underside Sb of the substrate S and the upper surface of the stage are arranged alternately. The levitation control mechanism 35 controls the amount of compressed air ejected from the nozzle holes and the amount of air sucked from the suction holes, thereby precisely controlling the distance between the underside Sb of the substrate S and the upper surface of the coating stage 32. This controls the vertical direction Z position of the upper surface Sf of the substrate S passing above the coating stage 32 to a specified value. A specific configuration of the levitation stage section 3 can be that described, for example, in Japanese Patent No. 5346643. The amount of levitation on the coating stage 32 is calculated by the control unit 9 based on the detection results from sensors 61 and 62, which will be described in detail later, and can be adjusted with high precision by airflow control.

Substrate S, which is carried into the floating stage section 3 via the input transfer section 2, is imparted with a propulsive force in the (+X) direction by the rotation of the roller conveyor 21 and is transported onto the entrance floating stage 31. The entrance floating stage 31, coating stage 32, and exit floating stage 33 support the substrate S in a floating state, but do not have the function of moving the substrate S horizontally. The transportation of the substrate S in the floating stage section 3 is performed by the substrate transport section 5, which is located below the entrance floating stage 31, coating stage 32, and exit floating stage 33.

The substrate transport unit 5 includes a chuck mechanism 51 that supports the substrate S from below by partially contacting the peripheral edge of the lower surface of the substrate S, and a suction/travel control mechanism 52 that applies negative pressure to a suction pad (not shown) attached to the suction member at the top end of the chuck mechanism 51 to suction-hold the substrate S and travels the chuck mechanism 51 back and forth in the X direction. When the chuck mechanism 51 holds the substrate S, the lower surface Sb of the substrate S is positioned higher than the upper surfaces of the stages of the floating stage unit 3. Therefore, while the peripheral edge of the substrate S is suction-held by the chuck mechanism 51, the buoyancy applied by the floating stage unit 3 maintains the substrate S in an overall horizontal position. A thickness measurement sensor 61 is located near the roller conveyor 21 to detect the vertical Z position of the upper surface of the substrate S when the lower surface Sb of the substrate S is partially held by the chuck mechanism 51. A chuck (not shown) not holding a substrate S is positioned directly below this sensor 61, allowing the sensor 61 to detect the position of the upper surface of the suction member, i.e., the suction surface, in the vertical direction Z.

The chuck mechanism 51 holds the substrate S that has been carried from the input transfer unit 2 to the floating stage unit 3. As the chuck mechanism 51 moves in the (+X) direction in this state, the substrate S is transported from above the entrance floating stage 31, past above the coating stage 32, to above the exit floating stage 33. The transported substrate S is then handed over to the output transfer unit 4, which is located on the (+X) side of the exit floating stage 33.

The output transfer unit 4 includes a roller conveyor 41 and a rotation/elevation drive mechanism 42 that rotates and elevates the roller conveyor 41. As the roller conveyor 41 rotates, a propulsive force is applied to the substrate S in the (+X) direction, and the substrate S is further transported along the transport direction Dt. As the roller conveyor 41 elevates, the position of the substrate S in the vertical direction Z is changed. The output transfer unit 4 transfers the substrate S from above the exit floating stage 33 to the output conveyor 110.

The output conveyor 110 comprises a roller conveyor 111 and a rotation drive mechanism 112 that drives it to rotate. The rotation of the roller conveyor 111 further transports the substrate S in the (+X) direction, and it is finally dispensed outside the coating apparatus 1. The input conveyor 100 and output conveyor 110 may be provided as part of the coating apparatus 1 configuration, or may be separate from the coating apparatus 1. For example, a substrate dispensing mechanism that is a separate unit provided upstream of the coating apparatus 1 may be used as the input conveyor 100. Furthermore, a substrate receiving mechanism that is a separate unit provided downstream of the coating apparatus 1 may be used as the output conveyor 110.

A coating mechanism 7 for coating the upper surface Sf of the substrate S is disposed on the transport path of the substrate S transported in this manner. The coating mechanism 7 has a slit nozzle (hereinafter simply referred to as "nozzle") 71 with a slit-shaped discharge outlet. Although not shown, a positioning mechanism is connected to the nozzle 71, which positions the nozzle 71 at a coating position above the coating stage 32 (the position indicated by the solid line in Figure 1) or at a maintenance position, which will be described later. Furthermore, a coating liquid supply mechanism 8 is connected to the nozzle 71, and the coating liquid is supplied from the coating liquid supply mechanism 8 and discharged from a discharge outlet that opens downward at the bottom of the nozzle.

Figure 2 shows the configuration of the coating liquid supply mechanism. As shown in Figure 2, the coating liquid supply mechanism 8 uses a pump 81 that supplies the coating liquid by changing its volume as a supply source for supplying the coating liquid to the nozzle 71. The pump 81 may be, for example, a bellows-type pump as described in Japanese Patent Application Laid-Open No. 10-61558. This pump 81 has a flexible tube 811 that is elastically expandable and contractible in the radial direction. One end of this flexible tube 811 is connected to a coating liquid refill unit 83 via piping 82, and the other end is connected to the nozzle 71 via piping 84.

A bellows 812, which is elastically deformable in the axial direction, is arranged on the outside of the flexible tube 811. This bellows 812 has a small bellows section 813 and a large bellows section 814, and a non-compressible medium is sealed in a pump chamber 815 between the flexible tube 811 and the bellows 812. An operating disk section 816 is provided between the small bellows section 813 and the large bellows section 814. A drive section 817 is connected to the operating disk section 816. When the drive section 817 operates in response to a command from the control unit 9, the operating disk section 816 is displaced axially according to a predetermined movement pattern (a pattern indicating changes in the speed of the operating disk section 816 over time), changing the volume inside the bellows 812. This causes the flexible tube 13 to expand and contract radially, performing a pumping operation and supplying the coating liquid, which is appropriately replenished from the coating liquid refill unit 83, toward the nozzle 71. For this reason, the movement pattern of the actuation disk portion 816 is closely related to the discharge characteristics (time-dependent changes in discharge pressure) of the coating liquid discharged from the nozzle 71, and predetermined discharge characteristics can be obtained depending on the movement pattern.

The coating liquid replenishment unit 83 has a storage tank 831 that stores the coating liquid. This storage tank 831 is connected to the pump 81 by a pipe 82. An on-off valve 833 is also inserted in the pipe 82. This on-off valve 833 opens in response to a replenishment command from the control unit 9, allowing the coating liquid in the storage tank 831 to be replenished into the flexible tube 811 of the pump 81. Conversely, it closes in response to a replenishment stop command from the control unit 9, restricting the replenishment of coating liquid from the storage tank 831 to the flexible tube 811 of the pump 81.

An on-off valve 85 is inserted in the pipe 84 connected to the output side (left hand side in the figure) of the pump 81, and opens and closes in response to an on-off command from the control unit 9. This allows the supply of coating liquid to the nozzle 71 to be switched on and off. A pressure gauge 86 is also attached to the pipe 84, which detects the pressure (discharge pressure) of the coating liquid being supplied to the nozzle 71 and outputs the detection result (pressure value) to the control unit 9.

As shown in FIG. 2, the nozzle 71 to which the coating liquid is supplied from the coating liquid supply mechanism 8 is equipped with a floating height detection sensor 62 for non-contact detection of the floating height of the substrate S. This sensor 62 can measure the distance between the floating substrate S and the upper surface of the stage surface of the coating stage 32, and the control unit 9 controls a positioning mechanism (not shown) based on the detected value to adjust the position to which the nozzle 71 descends. Note that the sensor 62 can be an optical sensor, an ultrasonic sensor, or the like.

As shown in Figure 1, the coating mechanism 7 is provided with a nozzle cleaning standby unit 72 to perform prescribed maintenance on the nozzle 71. The nozzle cleaning standby unit 72 mainly includes a roller 721, a cleaning section 722, and a roller butt 723. These are used to clean the nozzle and form a liquid pool, preparing the nozzle 71's discharge port for the next coating process. In addition, the nozzle 71 is positioned at the position where the nozzle cleaning standby unit 72 is provided, i.e., the maintenance position, and a simulated discharge is performed in which the coating liquid is discharged from the nozzle 71 to evaluate the discharge pressure applied to the coating liquid.

The coating apparatus 1 further includes a control unit 9 (Figure 3) for controlling the operation of each component of the apparatus. Figure 3 is a block diagram showing an example of the control unit's configuration. As shown in Figure 3, the control unit 9 is a computer equipped with a calculation unit 91, a memory unit 93, and a UI (User Interface) 95. The calculation unit 91 is a processor including a CPU (Central Processing Unit) and executes a discharge pressure evaluation program 97 to implement a measurement execution unit 911 that measures the discharge pressure and a pressure evaluation unit 913 that evaluates the measured discharge pressure. The memory unit 93 is a storage device such as an HDD (Hard Disk Drive) or SSD (Solid State Drive), and stores the discharge pressure evaluation program 97 and discharge pressure measurement data 99 measured in conjunction with the execution of the discharge pressure evaluation program 97. The discharge pressure evaluation program 97 is provided, for example, by a recording medium M provided separately from the control unit 9. The recording medium M records the discharge pressure evaluation program 97 in a manner readable by the computer (control unit 9). Examples of such recording media M include a USB (Universal Serial Bus) memory, a memory card, or a storage device of an external server computer. The UI 95 also includes a display that displays information to the user and an input device that accepts input operations by the user. Various types of computers, such as desktop, laptop, or tablet computers, can be used as the control unit 9 with this configuration.

Figure 4 is a flowchart showing an example of a discharge pressure evaluation method executed based on a discharge pressure evaluation program. In step 101, the measurement execution unit 911 moves the actuating disk unit 816 based on a movement pattern defined in the discharge pressure evaluation program 97, thereby discharging the coating liquid from the nozzle 71 (simulated discharge). As a result, the actuating disk unit 816 accelerates from a zero speed to a predetermined target speed, moves at a constant speed at the target speed, and then decelerates from the target speed to a zero speed. However, as shown in Patent Document 2, during the local period from when the speed of the actuating disk unit 816 reaches its maximum speed until it stabilizes at the target speed, the speed (parameter) of the actuating disk unit 816 is adjusted to set the movement pattern.

Specifically, the movement pattern of the operating disk portion 816 is defined in the discharge pressure evaluation program 97 so that the discharge pressure changes in the following order: the discharge pressure increases from the initial pressure Pi to a target pressure Pt that is greater than the initial pressure Pi; the discharge pressure stabilizes at the target pressure Pt; and the discharge pressure decreases from the target pressure Pt to the initial pressure Pi.

Furthermore, in step S101, the measurement execution unit 911 periodically acquires the measured value of the discharge pressure from the pressure gauge 86 at a predetermined sampling period in parallel with the discharge of the coating liquid from the nozzle 71 accompanying the movement of the actuation disk unit 816. In this way, the measurement result of the discharge pressure applied to the coating liquid during the discharge period Tt (Figure 5) when the coating liquid is discharged from the nozzle 71 is acquired and stored in the memory unit 93 as discharge pressure measurement data 99. This discharge pressure measurement data 99 indicates the time and the value of the discharge pressure measured at that time in association with each other.

In step S102, the pressure evaluation unit 913 evaluates the time change in the discharge pressure indicated by the discharge pressure measurement data 99 according to predetermined evaluation items. As described below, these evaluation items extract predetermined feature quantities from the time change in the discharge pressure indicated by the discharge pressure measurement data 99 and evaluate the time change in the discharge pressure based on these feature quantities. Next, each evaluation item used to evaluate the time change in the discharge pressure indicated by the discharge pressure measurement data 99 will be described in detail.

Figure 5 is a diagram illustrating each period used in evaluating the discharge pressure. Figure 5 shows a graph in which the horizontal axis represents time and the vertical axis represents discharge pressure, schematically illustrating the change in discharge pressure over time. This graph notation is also used in the figures shown later. In the example of Figure 5, discharge pressure measurement data 99 is acquired from before discharge of the coating liquid from the nozzle 71 begins until after discharge of the coating liquid from the nozzle 71 ends (i.e., over the discharge period Tt). In this example, the discharge pressure at time ta when discharge of the coating liquid from the nozzle 71 begins and the discharge pressure at time te when discharge of the coating liquid from the nozzle 71 ends are the initial pressure Pi. However, the pressures at the start and end of discharge do not always match the initial pressure Pi.

As shown in Figure 5, the discharge period Tt can be divided into four periods Ta, Tb, Tc, and Td. Details of the rise period Ta, transition period Tb, steady-state period Tc, and fall period Td are as follows:

The rise period Ta is the period from time ta when the coating liquid supply mechanism 8 starts discharging the coating liquid from the nozzle 71 (i.e., time ta when the coating liquid supply mechanism 8 starts moving the operating disk portion 816) to time tb when the discharge pressure reaches the target pressure Pt. In other words, when the discharge of the coating liquid from the nozzle 71 starts at time ta, the discharge pressure increases from the initial pressure Pi to the target pressure Pt between time ta and time tb.

The transition period Tb is the period from time tb to time tc, when a predetermined vibration damping period has elapsed. This vibration damping period is the period required for the time change in the discharge pressure to stabilize, and is set, for example, by a user through an input operation on the UI 95 and stored in the memory unit 93.

The steady-state period Tc is the period from time tc to time td when the coating liquid supply mechanism 8 begins to reduce the discharge pressure (i.e., time td when the coating liquid supply mechanism 8 begins to decelerate the operating disc portion 816 from the target speed). In other words, the coating liquid supply mechanism 8 moves the operating disc portion 816 at a constant speed from time tc to time td, and begins to decelerate the operating disc portion 816 at time td. During the steady-state period Tc, the discharge pressure basically stabilizes at the target pressure Pt. However, even during the steady-state period Tc, the change in the discharge pressure over time includes slight vibrations, and the discharge pressure may be greater or less than the target pressure Pt.

Furthermore, the transition period Tb and the steady-state period Tc constitute the constant pressure period Tbc. In other words, the constant pressure period Tbc is the period between time tb and time td.

The fall period Td is the period from time td to time te when the coating liquid supply mechanism 8 stops discharging the coating liquid from the nozzle 71 (i.e., time te when the coating liquid supply mechanism 8 stops the operating disk portion 816). In other words, the discharge pressure decreases to the initial pressure Pi between time td and time te, and at time te, discharging of the coating liquid from the nozzle 71 stops.

6 is a diagram schematically showing an example of a calculation performed by the pressure evaluation unit with respect to the time change in the discharge pressure. As shown in FIG. 6, the pressure evaluation unit 913 calculates a first derivative D1 of the time change in the discharge pressure by differentiating the time change in the discharge pressure. Furthermore, the pressure evaluation unit 913 calculates a second derivative D2 of the time change in the discharge pressure by differentiating the first derivative D1 of the time change in the discharge pressure by time. Furthermore, the pressure evaluation unit 913 calculates each of the following equations: MAE(α, β)=(1/n)·(Σ|α-β|)
RMSE (α, β) = ((1/n)・(Σ(α−β) ² )) ^1/2
Based on n = number of data, the mean absolute error (MAE) and the root mean square error (RMSE) are calculated.

Figure 7 is a diagram illustrating an evaluation item for evaluating the time change in discharge pressure based on the feature value Fv1. The evaluation item in Figure 7 evaluates the time change in discharge pressure indicated by the discharge pressure measurement data 99 based on the error (ideal trapezoid absolute error) between a trapezoidal waveform having an amplitude equivalent to the difference between the average value of the discharge pressure during the steady period Tc (i.e., steady pressure Pm) and the initial pressure Pi and the discharge pressure measurement data 99.

Specifically, during the rise period Ta, a linear regression analysis is performed on the change in discharge pressure over time between a predetermined lower reference pressure and a predetermined upper reference pressure that is greater than the lower reference pressure, and the rise regression line Lr_R is calculated. This rise regression line Lr_R linearly increases from the initial pressure Pi to the steady-state pressure Pm between time t11 and time t12.

Similarly, during the fall period Td, a linear regression analysis is performed on the time change in discharge pressure between the upper and lower reference pressures to calculate the fall regression line Lr_F. This fall regression line Lr_F linearly decreases from the steady pressure Pm to the initial pressure Pi between time t13 and time t14.

The lower reference pressure and upper reference pressure are pressures that are greater than the initial pressure Pi and less than the target pressure Pt, and are set, for example, by a user through input operations on the UI 95 and stored in the memory unit 93. In this example, the lower reference pressure is a pressure obtained by adding 20% of the absolute value of the difference between the initial pressure Pi and the target pressure Pt to the initial pressure Pi, and the upper reference pressure is a pressure obtained by adding 80% of the absolute value of the difference between the initial pressure Pi and the target pressure Pt to the initial pressure Pi.

In addition, a start-time approximated line Lr_s is set for the section from time ta to time t11. This start-time approximated line Lr_s is a line with a slope of zero that indicates the initial pressure Pi. In other words, the start-time approximated line Lr_s is a line that connects the time (time ta) when the application liquid starts to be ejected from the nozzle 71 to the start time of the rising regression line Lr_R. Note that, depending on the state (slope) of the regression line, time t11 may be before time ta, and time t12 may be after time tb. As a result, if t11 < ta, the start-time approximated line Lr_s is omitted.

In addition, an end-time approximated line Lr_e is set for the section from time t14 to time te. This end-time approximated line Lr_e is a line with a zero slope that indicates the initial pressure Pi. In other words, the end-time approximated line Lr_e is a line that connects the end point of the falling regression line Lr_F to the end point (time te) of the ejection of the application liquid from the nozzle 71. Note that if te<t14, the end-time approximated line Lr_e is omitted.

Furthermore, a steady line Lr_m is set for the section from time t12 to time t13. This steady line Lr_m is a line with a zero slope that indicates the steady pressure Pm. In other words, the steady line Lr_m is a line that indicates the steady pressure Pm, connecting the end point (time t12) of the rising regression line Lr_R and the start point (time t13) of the falling regression line Lr_F.

In this way, an approximate waveform WF1 is calculated, which is composed of the start approximate line Lr_s, the rising regression line Lr_R, the steady line Lr_m, the falling regression line Lr_F, and the end approximate line Lr_e, all arranged in chronological order. The pressure evaluation unit 913 then calculates the mean absolute error MAE (ideal trapezoid absolute error) between the discharge pressure measurement data 99 and the approximate waveform WF1 over the entire discharge period Tt from time ta to time te, as a feature value Fv1. The pressure evaluation unit 913 also normalizes the feature value Fv1 to a range of 0 to 2, based on a predetermined threshold value Th1 (e.g., 0.05). Specifically, if Fv1<Th1, then Fv1=0.
If Fv1≧Th1, Fv1=(Fv1+1−Th1)×c1
The feature Fv1 is converted into a normalized feature Fv1 (i.e., evaluation value V1) based on the above equation (2). Here, coefficient c1 is a normalization coefficient, and is set in advance to a value (e.g., 15) that causes the feature Fv1 to fall within a range of 2 or less.

According to the evaluation based on the feature Fv1 in Figure 7, if the change in the discharge pressure over time throughout the entire discharge period Tt deviates significantly from the ideal shape (i.e., a trapezoidal shape), a high score (i.e., a poor evaluation) can be given to this discharge pressure.

Figure 8 is a diagram illustrating evaluation items for evaluating temporal changes in discharge pressure based on the feature value Fv2. The evaluation items in Figure 8 evaluate the smoothness of the rise in discharge pressure. Specifically, during the rise period Ta, a curve regression analysis is performed on the temporal change in discharge pressure between the lower reference pressure P2_l and the upper reference pressure P2_u, which is greater than the lower reference pressure P2_l, to calculate the rise regression curve Nr. This curve regression analysis is performed using a quadratic curve.

The lower reference pressure P2_l is set to the initial pressure Pi. On the other hand, the upper reference pressure P2_u is a pressure that is greater than the lower reference pressure P2_l and less than the target pressure Pt, and is set, for example, by a user through input operations on the UI 95 and stored in the memory unit 93. In this example, the upper reference pressure P2_u is a pressure obtained by adding 20% of the absolute value of the difference between the initial pressure Pi and the target pressure Pt to the initial pressure Pi. This rising regression curve Nr increases from the lower reference pressure P2_l (initial pressure Pi) to the upper reference pressure P2_u between time t21 and time t22. Note that time t21 coincides with time ta, and time t22 is after time ta and before time tb.

In this way, the waveform WF2 configured by the rising regression curve Nr is calculated. Then, the pressure evaluation unit 913 calculates the root mean square error RMSE between the discharge pressure measurement data 99 and the waveform WF2 during the initial rising period Ta_s from time t21 to time t22 as the feature amount Fv2. Furthermore, the pressure evaluation unit 913 normalizes the feature amount Fv2 to a range of 0 to 2 based on a predetermined threshold value Th2 (e.g., 0.05). Specifically, if Fv2<Th2, then Fv2=0.
If Fv2≧Th2, Fv2=2
Based on this, the feature value Fv2 is converted into a normalized feature value Fv2 (i.e., evaluation value V2).

According to the evaluation based on the feature Fv2 in Figure 8, if an abnormality occurs in the discharge pressure immediately after the start of discharge due to the influence of the state before the start of discharge of the coating liquid from the nozzle 71, a large score (i.e., a poor evaluation) can be given to this discharge pressure. Note that the curves that can be used in the curve regression analysis are not limited to quadratic curves, and other curves such as exponential functions can also be used.

FIG. 9 is a diagram illustrating an evaluation item for evaluating the change over time in the discharge pressure based on the characteristic amount Fv3. The evaluation item in FIG. 9 evaluates whether the rise period Ta is within a certain period. Specifically, the pressure evaluation unit 913 calculates the length of the rise period Ta (=tb-ta) from time ta to time tb required for the discharge pressure to increase from the initial pressure Pi to the target pressure Pt as the characteristic amount Fv3. Furthermore, the pressure evaluation unit 913 normalizes the characteristic amount Fv3 to a range of 0 to 1 based on a predetermined threshold value Th3 (e.g., 350 ms). Specifically, if Fv3<Th3, then Fv3=0.
If Fv3≧Th3, then Fv2=1
Based on this, the feature value Fv3 is converted into a normalized feature value Fv3 (i.e., evaluation value V3).

According to the evaluation based on the feature Fv3 in Figure 9, a high score (i.e., a poor evaluation) can be given to a discharge pressure that takes time to rise to the target pressure Pt.

Figure 10A is a diagram illustrating an evaluation item for evaluating the time change in discharge pressure based on the feature quantity Fv4, and Figure 10B is a diagram showing an example of time change in discharge pressure that is determined to be inappropriate by evaluation based on the feature quantity Fv4. The evaluation item in Figure 10A evaluates whether or not there is an abnormality in the rise of the discharge pressure. Specifically, the pressure evaluation unit 913 calculates the first-order derivative D1 of the time change in discharge pressure for the rise period Ta from time ta to time tb, to obtain the first-order derivative waveform WF4.

The pressure evaluation unit 913 then determines the number of times the first-order differential waveform WF4 crosses a predetermined threshold value Th4 during the rising period Ta as the feature value Fv4. In the example of FIG. 10A, the first-order differential waveform WF4 crosses the threshold value Th4 (e.g., 0.002) at both time t41 and time t42, and the number of crossings (feature value Fv4) is two. The pressure evaluation unit 913 also normalizes the feature value Fv4 to a range of 0 to 1. Specifically, if Fv4≦2, then Fv4=0.
If Fv4>2, then Fv4=1
Based on this, the feature value Fv4 is converted into a normalized feature value Fv4 (i.e., evaluation value V4).

According to the evaluation based on the feature Fv4 in Figure 10A, if a step occurs in the time change of the discharge pressure during the rise period Ta (for example, as shown in Figure 10B), a high score (i.e., a poor evaluation) can be given to this discharge pressure.

Figure 11A is a diagram illustrating an evaluation item for evaluating the time change in discharge pressure based on the feature quantity Fv5, and Figure 11B is a diagram showing an example of time change in discharge pressure that is determined to be inappropriate by evaluation based on the feature quantity Fv5. The evaluation item in Figure 11A evaluates whether or not there is an abnormality in the rise of the discharge pressure. Specifically, the pressure evaluation unit 913 calculates the second-order derivative D2 of the time change in discharge pressure for the rise period Ta from time ta to time tb, to obtain the second-order derivative waveform WF5.

The pressure evaluation unit 913 then determines the number of times that the absolute value of the twice-differentiated waveform WF5 intersects with a predetermined threshold value Th5 during the rising period Ta as the feature value Fv5. In the example of FIG. 11A, the absolute value of the twice-differentiated waveform WF5 intersects with the threshold value Th5 (e.g., 0.0002) at times t51, t52, t53, and t54, respectively, and the number of intersections (feature value Fv5) is four. The pressure evaluation unit 913 also normalizes the feature value Fv5 to a range of 0 to 1. Specifically, if Fv5=4 in the following equation, then Fv5=0
If Fv5≠4, then Fv5=1
Based on this, the feature value Fv5 is converted into a normalized feature value Fv5 (i.e., evaluation value V5).

According to the evaluation based on the feature Fv5 in Figure 11A, if a step occurs in the time change of the discharge pressure during the rise period Ta (for example, as shown in Figure 11B), a high score (i.e., a poor evaluation) can be given to this discharge pressure.

Figure 12 is a diagram illustrating an evaluation item for evaluating the time change in discharge pressure based on the feature quantity Fv6. The evaluation item in Figure 12 evaluates whether the rise in discharge pressure stalls in the latter half. Specifically, the pressure evaluation unit 913 calculates the second-order derivative D2 of the time change in discharge pressure for the rise period Ta from time ta to time tb to obtain the second-order derivative waveform WF6.

The pressure evaluation unit 913 then calculates, during the rising period Ta, the time T_1st at which the second-order differential waveform WF6 exceeds a predetermined positive threshold (Th5) and the time T_2nd at which the second-order differential waveform WF6 falls below a predetermined negative threshold (-Th5). Here, the positive threshold and the negative threshold have the same absolute value (Th5) but different signs. The absolute values (Th5) of the positive and negative thresholds are equal to the threshold Th5 used in the evaluation using the feature Fv5. The pressure evaluation unit 913 then calculates the ratio of these times (=T_1st/T_2nd) as the feature Fv6. Furthermore, the pressure evaluation unit 913 calculates the feature Fv6 using the following equation: Fv6=|1-Fv6|
The feature Fv6 is converted based on the above.

Furthermore, the pressure evaluation unit 913 normalizes the converted feature quantity Fv6 to a range of 0 to 2 using a predetermined threshold value Th6 (for example, 0.2). Specifically, if Fv6<Th6, then Fv6=0.
If Fv6≧Th6, then Fv6=f(Fv6)
f(γ)=4×γ-0.8
The feature value Fv6 is converted into a normalized feature value Fv6 (i.e., evaluation value V6) based on the above. Note that the function f(γ) with γ as a variable is not limited to the example given here, and can be changed arbitrarily.

The transport speed of the substrate S to be coated with the coating liquid reaches the target speed without stalling, even in the latter half of the acceleration period. Therefore, it is preferable that the discharge pressure applied to the coating liquid also reaches the target pressure Pt without stalling during the rise period Ta. In contrast, according to the evaluation based on the feature Fv6 in Figure 12, if the discharge pressure stalls during the rise period Ta, a high score (i.e., a poor evaluation) can be given to this discharge pressure.

Figure 13 is a diagram illustrating evaluation items for evaluating temporal changes in discharge pressure based on the feature Fv7. The evaluation items in Figure 13 evaluate the sharpness of temporal changes in discharge pressure at the end of the rise. Specifically, during the rise period Ta, linear regression analysis is performed on the temporal change in discharge pressure between the lower reference pressure P7_l and the upper reference pressure P7_u, which is greater than the lower reference pressure P7_l, to calculate the rise end regression line Lr. Here, the lower reference pressure P7_l is the pressure obtained by adding 80% of the absolute value of the difference between the initial pressure Pi and the target pressure Pt to the initial pressure Pi. The upper reference pressure P7_u is the pressure obtained by adding 90% of the absolute value of the difference between the initial pressure Pi and the target pressure Pt to the initial pressure Pi. The discharge pressure increases from the lower reference pressure P7_l to the upper reference pressure P7_u between time t71 and time t72.

This rise end regression line Lr increases over time and reaches steady-state pressure Pm (the average value of the discharge pressure during the steady-state period Tc) at time t73. In this way, the rise end regression line Lr is set for the section from time t71 to time t73. Furthermore, the pressure evaluation unit 913 sets an extension line Lm with a zero slope that indicates the steady-state pressure Pm between time t73 and time tb. As described above, time tb is the time when the discharge pressure reaches the target pressure Pt, and corresponds to the end of the rise period Ta. In other words, this extension line Lm is set to extend from (the end point of) the rise end regression line Lr to the end point of the rise period Ta. Note that if tb < t73, the extension line Lm is omitted.

In this way, an approximate waveform WF7 is calculated that is composed of the rise end regression line Lr and the extension line Lm arranged in chronological order. Then, the pressure evaluation unit 913 calculates, as a feature quantity Fv7, a value that indicates the difference between the discharge pressure measurement data 99 and the approximate waveform WF7 during a rise end period Ta_e from time t72, when the discharge pressure reaches 90% of the target pressure Pt, to time tb, when the discharge pressure reaches 100%. Specifically, a weighted reference time width Tw=t73-t72 is set. Then, the weighted root-mean-square error sum is calculated using the following equation: Fv7=(Σ(P_measure-WF7) ² ×W) ^1/2
P_measure = discharge pressure measurement data 99
W=1 in the range of time tb≦t73+2×Tw
In the range of time tb>t73+2×Tw, W=w
w is a weighting factor greater than 1, for example 10, calculated based on the

Furthermore, the pressure evaluation unit 913 normalizes the feature amount Fv7 to a range of 0 to 2 based on a predetermined threshold value Th7 (for example, 0.6). Specifically, if Fv7<Th7, then Fv7=0.
If Fv7≧Th7, Fv7=Fv7/c7
c7 is an arbitrary positive constant, for example, 1.1, and based on this, the feature value Fv7 is converted into a normalized feature value Fv7 (i.e., evaluation value V7).

According to the evaluation based on the feature Fv7 in Figure 13, if the change in the discharge pressure over time shows a rounded waveform with a weak rising momentum, a high score (i.e., a poor evaluation) can be given to this discharge pressure.

Figure 14 is a diagram illustrating evaluation items for evaluating temporal changes in discharge pressure based on the feature quantity Fv8. The evaluation items in Figure 14 evaluate the degree of overshoot that occurs when the discharge pressure rises. Specifically, the pressure evaluation unit 913 calculates the sign (positive/negative) of the second-order derivative D2 of the discharge pressure at time t81, when the discharge pressure reaches its maximum value Pmax. The pressure evaluation unit 913 then calculates time t82, when the sign of the second-order derivative D2 of the discharge pressure switches twice from the sign at time t81. The time change in discharge pressure during the initial vibration period Tb_s from time t81 to time t82 is then evaluated.

Specifically, the minimum value P8min of the time change of the discharge pressure during this initial vibration period Tb_s is obtained, and the smaller of the steady pressure Pm and the pressure P8min is selected as the target pressure Pg. Then, the difference between the maximum pressure Pmax and the target pressure Pg, that is, the following equation, Fv8=Pmax-Pg
The feature value Fv8 is calculated based on the above.

Furthermore, the pressure evaluation unit 913 normalizes the feature quantity Fv8 to a range of 0 to 2 using a predetermined threshold value Th8 (for example, 0.035). Specifically, if Fv8<Th8, then Fv8=0
If Fv8≧Th8, Fv8=Fv8/c8
c8 is an arbitrary positive constant, for example, 0.12, and based on this, the feature value Fv8 is converted into a normalized feature value Fv8 (i.e., evaluation value V8).

According to the evaluation based on the feature Fv8 in Figure 14, if the change in discharge pressure over time shows a strong rise and a large overshoot, a high score (i.e., a poor evaluation) can be given to this discharge pressure.

15 is a diagram illustrating an evaluation item for evaluating the time change of the discharge pressure based on the feature amount Fv9. The evaluation item in FIG. 15 evaluates the stability of the time change of the discharge pressure in the transition period Tb. Specifically, the pressure evaluation unit 913 calculates the stability of the time change of the discharge pressure in the transition period Tb and the steady pressure Pm, which is the average value of the discharge pressure in the steady period Tc, using the following equation: Fv9=RMSE(P_measure, Pm)
P_measure = discharge pressure measurement data 99
Based on this, the root mean square error RMSE(P_measure, Pm) is calculated as the feature Fv9.

Furthermore, the pressure evaluation unit 913 normalizes the feature amount Fv9 to a range of 0 to 2. Specifically, Fv9=Fv9/c9
c9 is an arbitrary positive constant, for example, 0.04, and based on this, the feature value Fv9 is converted into a normalized feature value Fv9 (i.e., evaluation value V9).

According to the evaluation based on the feature Fv9 in Figure 15, if the change in discharge pressure over time indicates ringing during the transition period Tb, a high score (i.e., a poor evaluation) can be given to this discharge pressure.

FIG. 16 is a diagram illustrating an evaluation item for evaluating the time change of the discharge pressure based on the feature amount Fv10. The evaluation item in FIG. 16 evaluates the stability of the time change of the discharge pressure during the constant pressure period Tbc. Specifically, the pressure evaluation unit 913 obtains the maximum value Pmax and the minimum value P10min of the discharge pressure during the constant pressure period Tbc. Then, the pressure evaluation unit 913 calculates the difference between the maximum pressure Pmax and the minimum pressure P10min during the constant pressure period Tbc, that is, the following equation: Fv10=Pmax-P10min
The feature value Fv10 is calculated based on the above.

Furthermore, the pressure evaluation unit 913 normalizes the feature quantity Fv10 to a range of 0 to 2 using a threshold value Th10 (for example, 0.12). Specifically, if Fv10<Th10, then Fv10=0.
If Fv10≧Th10, Fv10=Fv10/Th10
Based on this, the feature value Fv10 is converted into a normalized feature value Fv10 (i.e., evaluation value V10).

According to the evaluation based on the feature Fv10 in Figure 16, if the change in ejection pressure over time shows large variations during the steady period Tc, which has a large impact on the film thickness of the coating liquid, a large score (i.e., a poor evaluation) can be given to this ejection pressure.

In this way, the pressure evaluation unit 913 calculates evaluation values V1 to V10 based on the results of extracting each of the feature quantities Fv1 to Fv10 from the discharge pressure measurement data 99. The pressure evaluation unit 913 then calculates the sum of these evaluation values V1 to V10 as the final evaluation value for the change over time in the discharge pressure indicated by the discharge pressure measurement data 99 (step S102).

In the embodiment described above, the discharge pressure is measured during the discharge period Tt (first period, evaluation period) from the start of discharge of the application liquid (treatment liquid) from the nozzle 71 to the end of discharge of the application liquid from the nozzle 71 (step S101). Then, the ideal trapezoid absolute error of the time change in the discharge pressure during the entire discharge period Tt is extracted as a feature quantity Fv1 (first feature quantity, overall feature quantity), and the time change in the discharge pressure is evaluated based on this feature quantity Fv1 (step S102). This makes it possible to reflect the appropriateness of the discharge pressure during the entire discharge period Tt, from the start to the end of discharge of the application liquid from the nozzle 71, in the evaluation of the discharge pressure.

Furthermore, as shown in FIG. 7, the feature value Fv1 indicates the difference between the approximate waveform WF1 (first approximate waveform) that approximates the change in the discharge pressure over time during the entire discharge period Tt, and the change in the discharge pressure over time during the entire discharge period Tt. With this configuration, the discharge pressure over the entire discharge period Tt can be appropriately evaluated based on the approximate waveform WF1 of the change in the discharge pressure over time during the entire discharge period Tt, from the start to the end of the discharge of the application liquid from the nozzle 71.

In particular, the approximate waveform WF1 is
a rising regression line Lr_R (rising approximation line) that linearly increases over time from an initial pressure Pi (discharge start pressure) to a steady-state pressure Pm that is greater than the initial pressure Pi, by linearly approximating the time change in the discharge pressure that increases over time after the start of discharge of the coating liquid from the nozzle 71;
a start-time approximation line Lr_s that indicates the initial pressure Pi and is provided between the start time (time ta) of the discharge of the application liquid from the nozzle 71 and the rising regression line Lr_R;
a falling regression line Lr_F (falling approximation line) that linearly decreases over time from the steady pressure Pm to an initial pressure Pi (discharge end pressure) that is smaller than the steady pressure Pm, by linearly approximating the time change in the discharge pressure that decreases over time before the discharge of the coating liquid from the nozzle 71 is completed;
an end-time approximation line Lr_e that is provided between the falling regression line Lr_F and the end point (time te) of the discharge of the application liquid from the nozzle 71 and indicates the initial pressure Pi (discharge end pressure);
A steady line Lr_m indicating the steady pressure Pm is provided by connecting the rising regression line Lr_R and the falling regression line Lr_F. With this configuration, the time change in the discharge pressure during the entire discharge period Tt, from the start to the end of the discharge of the coating liquid from the nozzle 71, is approximated by a trapezoidal waveform, and the discharge pressure during the entire discharge period Tt can be appropriately evaluated.

Furthermore, feature quantities Fv2 to Fv10 (second feature quantities) possessed by the change in the discharge pressure over time during a period (second period) shorter than the discharge period Tt are extracted, and the change in the discharge pressure over time is evaluated based on the feature quantities Fv2 to Fv10 (step S102). With this configuration, the discharge pressure can be evaluated with high accuracy based on the change in the discharge pressure over time during both the entire discharge period Tt, from the start to the end of discharge of the coating liquid from the nozzle 71, and during periods shorter than the discharge period Tt.

Furthermore, the evaluation items shown in Figure 8 evaluate the discharge pressure during a predetermined initial rise period Ta_s (second period) from the start of discharge of the application liquid from the nozzle 71. Throughout this initial rise period Ta_s, the discharge pressure increases over time, and a feature value Fv2 (second feature value) is extracted that indicates the difference between the rise regression curve Nr of the time change in the discharge pressure during the initial rise period Ta_s and the time change in the discharge pressure during the initial rise period Ta_s. With this configuration, the discharge pressure can be evaluated by taking into account the time change in the discharge pressure immediately after the start of discharge of the application liquid from the nozzle 71.

In addition, the discharge pressure is evaluated during the rise period Ta (second period) from the start of discharge of the coating liquid from the nozzle 71 until the discharge pressure increases to the target pressure Pt (predetermined pressure). With this configuration, the discharge pressure can be evaluated taking into account the change in the discharge pressure over time during the rise period Ta.

Specifically, for the evaluation items shown in Figure 9, the length of the rise period Ta is extracted as feature value Fv2 (second feature value). With this configuration, the discharge pressure can be evaluated taking into account the speed at which the discharge pressure rises.

Furthermore, for the evaluation items shown in Figures 10A and 10B, the number of times that the first-order differential D1 of the time change in the discharge pressure intersects with a predetermined threshold Th4 during the rise period Ta is extracted as the feature Fv4 (second feature). With this configuration, the discharge pressure can be evaluated taking into account the smoothness of the time change in the discharge pressure during the rise period.

Furthermore, in the evaluation items shown in Figure 11, the number of times the absolute value of the second derivative D2 of the time change in the discharge pressure during the rise period Ta intersects with a predetermined threshold value Th5 is extracted as the feature Fv5 (second feature). With this configuration, the discharge pressure can be evaluated taking into account the smoothness of the time change in the discharge pressure during the rise period Ta.

Furthermore, for the evaluation items shown in Figure 12, the ratio of the time T_1st at which the second derivative D2 of the time change in the discharge pressure becomes greater than a predetermined positive threshold (Th5) during the rise period Ta to the time T_2nd at which the second derivative D2 of the time change in the discharge pressure becomes smaller than a negative threshold (-Th5) having the same absolute value as the positive threshold is extracted as feature Fv6 (second feature). With this configuration, the discharge pressure can be evaluated by taking into account the difference in the time change in the discharge pressure between the beginning and end of the rise period Ta.

Furthermore, the evaluation items shown in Figure 13 evaluate the discharge pressure during the final rise period Ta_e (second period) until the discharge pressure increases to the target pressure Pt (predetermined pressure). That is, an approximate waveform WF7 (final rise approximate waveform) that approximates the time change in the discharge pressure during the final rise period Ta_e is extracted, and a feature value Fv7 (second feature value) that indicates the difference between the time change in the discharge pressure during the final rise period Ta_e. This approximate waveform WF7 is composed of a final rise regression line Lr (final rise approximate line) and an extension line Lm. The final rise regression line Lr overlaps with an approximate curve obtained by linearly approximating the time change in the discharge pressure that increases over time in a pressure range (P7_l to P7_u) smaller than the target pressure Pt, and linearly increases over time to a steady-state pressure Pm. The extended line Lm extends from (the end point of) the rise end regression line Lr to the end point of the rise end period Ta_e, indicating the steady-state pressure Pm. With this configuration, the discharge pressure can be evaluated taking into account the degree of stall in the discharge pressure at the end of the rise period Ta.

Furthermore, the evaluation items shown in Figure 14 evaluate the discharge pressure during the initial oscillation period Tb_s (second period), from the point in time when the discharge pressure reaches its maximum value Pmax (time t81) to the point in time when the second derivative D2 of the time change in the discharge pressure crosses zero twice (time t82). Specifically, the minimum value P8min of the discharge pressure during the initial oscillation period Tb_s is determined, and the difference between the smaller of this minimum value P8min and the steady-state pressure Pm and the maximum value Pmax of the discharge pressure is extracted as the feature value Fv8 (second feature value). With this configuration, the discharge pressure can be evaluated taking into account the overshoot of the discharge pressure.

Furthermore, the evaluation items shown in Figure 15 evaluate the discharge pressure during a predetermined transition period Tb (second period) from the point (time tb) when the discharge pressure exceeds the target pressure Pt (predetermined pressure). Specifically, a feature quantity Fv9 (second feature quantity) indicating the difference between the discharge pressure during the rise period Ta and the steady-state pressure Pm is extracted. With this configuration, the discharge pressure can be evaluated taking into account the stability of the discharge pressure after it reaches the target pressure Pt.

Furthermore, the evaluation items shown in Figure 16 evaluate the discharge pressure during the constant pressure period Tbc, from the time (tb) when the discharge pressure exceeds the target pressure Pt (predetermined pressure) to the time (td) when the discharge pressure begins to decrease toward the end of discharge of the coating liquid from the nozzle 71. Specifically, a feature quantity Fv10 indicating the difference between the maximum value Pmax and minimum value P10min of the discharge pressure during the constant pressure period Tbc is extracted. With this configuration, the discharge pressure can be evaluated taking into account the stability of the discharge pressure during the constant pressure period Tbc.

As described above, in the above embodiment, the coating apparatus 1 corresponds to an example of a "substrate processing apparatus" of the present invention, the nozzle 71 corresponds to an example of a "nozzle" of the present invention, the coating liquid supply mechanism 8 corresponds to an example of a "pressure applying unit" of the present invention, the nozzle 71 and the coating liquid supply mechanism 8 cooperate to form an example of a "discharge apparatus" of the present invention, the pressure gauge 86 corresponds to an example of a "measurement unit" of the present invention, the control unit 9 corresponds to an example of a "computer" and "controller" of the present invention, the discharge pressure evaluation program 97 corresponds to an example of a discharge pressure evaluation program of the present invention, the recording medium M corresponds to an example of a "recording medium" of the present invention, the coating liquid corresponds to an example of a "treatment liquid" of the present invention, and the pressure measured by the pressure gauge 86 corresponds to an example of a "discharge pressure" of the present invention.

The discharge period Tt corresponds to an example of the "first period" of the present invention, the feature Fv1 corresponds to an example of the "first feature" of the present invention, the approximate waveform WF1 corresponds to an example of the "first approximate waveform" of the present invention, the initial pressure Pi corresponds to an example of the "discharge start pressure" and "discharge end pressure" of the present invention, the rising regression line Lr_R corresponds to an example of the "rising approximate line" of the present invention, the start approximate line Lr_s corresponds to an example of the "start approximate line" of the present invention, the falling regression line Lr_F corresponds to an example of the "falling approximate line" of the present invention, the end approximate line Lr_e corresponds to an example of the "end approximate line" of the present invention, and the steady line Lr_m corresponds to an example of the "steady line" of the present invention.

Furthermore, the initial rise period Ta_s, the rise period Ta, the final rise period Ta_e, the initial vibration period Tb_s, the transition period Tb, and the constant pressure period Tbc correspond to examples of the "second period" of the present invention, the feature quantities Fv2 to Fv10 correspond to examples of the "second feature quantities" of the present invention, the initial period Ta_s corresponds to an example of the "initial rise period" of the present invention, the regression curve Nr corresponds to an example of the "regression curve" of the present invention, the rise period Ta corresponds to an example of the "rise period" of the present invention, and the final rise period Ta_e corresponds to an example of the "second feature quantity" of the present invention. The approximate waveform WF7 corresponds to an example of a "rise end period" of the present invention, the approximate waveform WF7 corresponds to an example of a "rise end approximate waveform" of the present invention, the rise end regression line Lr corresponds to an example of a "rise end approximate line" of the present invention, the extended line Lm corresponds to an example of an "extended line" of the present invention, the initial vibration period Tb_s corresponds to an example of an "initial vibration period" of the present invention, the steady period Tc corresponds to an example of a "steady period" of the present invention, the transition period Tb corresponds to an example of a "transition period" of the present invention, and the constant pressure period Tbc corresponds to an example of a "constant pressure period" of the present invention.

The present invention is not limited to the above-described embodiment, and various modifications other than those described above are possible without departing from the spirit of the invention. For example, in the above embodiment, the discharge characteristics are measured based on the pressure value detected by the pressure gauge 86 attached to the pipe 82, but the installation position of the pressure gauge 86 is not limited to this; it can be installed in any position as long as it can detect the pressure of the coating liquid supplied to the nozzle 71.

Furthermore, in the above embodiment, a bellows-type pump 81 is used, but the type of pump is not limited to this. For example, a syringe-type pump using a piston (e.g., JP 2008-101510 A) may also be used.

In addition, in the above embodiment, the present invention is applied to a coating device 1 that supplies a coating liquid to the surface Sf of the substrate S while the substrate S is in a floating state, but the application of the present invention is not limited to this. The present invention can be applied to any substrate processing technology that supplies a processing liquid to a nozzle, and then supplies the processing liquid from the nozzle to the upper surface of the substrate to perform a predetermined process.

Furthermore, it is not necessary to evaluate the discharge pressure based on all of the above feature quantities Fv2 to Fv10; the discharge pressure may be evaluated based on only some of these. Alternatively, the discharge pressure may be evaluated based on only feature quantity Fv1.

Furthermore, when calculating the approximate waveform WF1 in Figure 7, a straight line with a zero slope indicating the target pressure Pt may be used instead of the steady line Lr_m.

Furthermore, instead of the feature quantity Fv1 shown in FIG. 7, a feature quantity Fv1_1, which will be described in the following modification, may be calculated, and the change in discharge pressure over time may be evaluated based on this feature quantity Fv1_1. FIG. 17 is a diagram illustrating the time periods used in a modification of the evaluation item for discharge pressure, and FIG. 18 is a diagram illustrating a modification of the evaluation item for evaluating the change in discharge pressure over time based on the feature quantity Fv1_1. Here, the differences between FIG. 17 and the above-mentioned FIG. 5 will be mainly described, and the common points will be denoted by equivalent reference numerals and their explanations will be omitted where appropriate. Similarly, the differences between FIG. 18 and the above-mentioned FIG. 7 will be mainly described, and the common points will be denoted by equivalent reference numerals and their explanations will be omitted where appropriate.

As shown in Figure 17, a modified evaluation item uses a period of interest Troi. This period of interest Troi is the period from time ta to time td. That is, the period of interest Troi is composed of a rise period Ta, a transition period Tb, and a steady period Tc; in other words, it is composed of a rise period Ta and a constant pressure period Tbc. In this way, the period of interest Troi corresponds to an example of "the main period from the start of ejection of treatment liquid from the nozzle, through the increase in the ejection pressure to a predetermined pressure, to the start of the decrease in the ejection pressure from the predetermined pressure" in this invention, and the target pressure Pt corresponds to an example of "predetermined pressure" in this invention.

As shown in FIG. 18, in this modified example, the rising regression line Lr_R is calculated and the start-time approximation line Lr_s is set in the same manner as in the case of the feature Fv1 described above. Furthermore, for the period from time t12 to time td, a steady line Lr_m_1 is set, which is a line with zero slope that indicates the steady pressure Pm (i.e., the average of the measured discharge pressure values during the steady period Tc).

In this way, an approximate waveform WF1_1 is calculated, which is composed of the start approximate line Lr_s, the rising regression line Lr_R, and the steady line Lr_m_1 arranged in chronological order. Then, the pressure evaluation unit 913 calculates the mean absolute error MAE between the discharge pressure measurement data 99 and the approximate waveform WF1_1 over the entire period of interest Troi from time ta to time td as the feature value Fv1_1. Furthermore, the pressure evaluation unit 913 normalizes the feature value Fv1_1 to a predetermined range based on a predetermined threshold value Th1_1 (e.g., 0.05). Specifically, if Fv1_1<Th1_1, then Fv1_1=0.
If Fv1_1≧Th1_1, Fv1_1=(Fv1_1+1-Th1_1)×c1_1
The feature Fv1_1 is converted into a normalized feature Fv1_1 (i.e., evaluation value V1_1) based on the above. Here, the upper limit of Fv1_1 is 2×c1_1, and the coefficient c1_1 is a normalization coefficient and is an arbitrary positive constant. Note that the specific method for normalizing the feature Fv1_1 is not limited to this example and may be changed as appropriate.

According to the evaluation based on the feature Fv1_1 in Figure 18, if the change in the discharge pressure over time throughout the period of interest Troi deviates significantly from the ideal shape, a high score (i.e., a poor evaluation) can be given to this discharge pressure.

In this modified example, in the measurement result evaluation (step S102) of the discharge pressure evaluation shown in FIG. 4, the pressure evaluation unit 913 calculates the evaluation value V1_1 based on the result of extracting the feature quantity Fv1_1 from the discharge pressure, rather than the feature quantity Fv1. Furthermore, in the same manner as described above, the pressure evaluation unit 913 calculates the evaluation values V2 to V10 based on the result of extracting the feature quantities Fv2 to Fv10 from the discharge pressure. The pressure evaluation unit 913 then calculates the sum of these evaluation values V1_1 and V2 to V10 as the final evaluation value for the time change in the discharge pressure indicated by the discharge pressure measurement data 99 (step S102).

In the modified example described above, the discharge pressure is measured during the period of interest Troi (main period, period to be evaluated) from the start of discharge of processing liquid from the nozzle 71, through the increase in the discharge pressure up to the target pressure Pt (predetermined pressure), until the discharge pressure starts to decrease from the target pressure Pt. Then, a feature quantity Fv1_1 (overall feature quantity) possessed by the change in the discharge pressure over time during the entire period of interest Troi is extracted, and the change in the discharge pressure over time is evaluated based on the feature quantity Fv1_1. This makes it possible to reflect the appropriateness of the discharge pressure over the entire period of interest Troi, which affects the thickness of the processing liquid applied to the substrate S, in the evaluation of the discharge pressure.

Furthermore, in this modified example, when the period of interest Troi has a particularly large effect on the thickness of the processing liquid applied to the substrate S (in other words, when the effect of the period after the period of interest Troi is small), it is possible to reflect the appropriateness of the discharge pressure throughout the entire period of interest Troi in the evaluation of the discharge pressure.

Furthermore, the feature Fv1_1 (main feature) indicates the difference between the approximate waveform WF1_1 (main approximate waveform) that approximates the time change in the discharge pressure throughout the period of interest Troi (main period), and the time change in the discharge pressure throughout the period of interest Troi. With this configuration, the discharge pressure throughout the period of interest Troi can be appropriately evaluated based on the approximate waveform WF1_1 of the time change in the discharge pressure throughout the period of interest Troi.

In particular, the approximate waveform WF1_1 is
a rising regression line Lr_R (rising approximation line) that linearly increases over time from an initial pressure Pi (discharge start pressure) to a steady-state pressure Pm that is greater than the initial pressure Pi, which is a linear approximation of the time change in the discharge pressure that increases over time after the start of discharge of the coating liquid from the nozzle 71; and
a start-time approximation line Lr_s that indicates the initial pressure Pi and is provided between the start time (time ta) of the discharge of the application liquid from the nozzle 71 and the rising regression line Lr_R;
The rising regression line Lr_R has a steady line Lr_m_1 that indicates the steady pressure Pm and is provided from the time when the rising regression line Lr_R reaches the steady pressure Pm until the end of the period of interest Troi (between time t12 and time td). With this configuration, the change in the discharge pressure over time during the entire period of interest Troi can be approximated, and the discharge pressure during the entire period of interest Troi can be appropriately evaluated.

Incidentally, when evaluating the discharge pressure using the feature Fv1_1 shown in Figure 18, there is no need to measure the discharge pressure in step S101 during the period after the period of interest Troi has elapsed (i.e., the falling period Td).

The UI 95 may also be configured to allow the user to select which of the two feature quantities Fv1 and Fv1_1 described above will be used to evaluate the discharge pressure. In this case, in step S102, the discharge pressure is evaluated using one of the feature quantities Fv1 and Fv1_1 selected by the user through an input operation on the UI 95.

This invention is applicable to general substrate processing technologies that supply processing liquid to a nozzle, which then ejects and supplies the processing liquid to a substrate with target characteristics.

1... Coating device (substrate processing device)
71...Nozzle (discharge device)
8... Coating liquid supply mechanism (pressure applying unit, ejection device)
86... Pressure gauge (measurement part)
9...Control unit (computer, control unit)
97... Discharge pressure evaluation program M... Recording medium Tt... Discharge period (first period)
Fv1: feature amount (first feature amount)
WF1...Approximate waveform (first approximate waveform)
Pi: Initial pressure (discharge start pressure, discharge end pressure)
Lr_R...rising regression line (rising approximation line)
Lr_s... Approximate line at start Lr_F... Falling regression line Lr_e... Approximate line at end Lr_m... Steady line Ta_s... Initial rise period (second period)
Ta: rising period (second period)
Ta_e... rising end period (second period)
Tb_s: Initial vibration period (second period)
Tb...Transition period (second period)
Tbc: constant pressure period (second period)
Fv2 to Fv10... feature amount (second feature amount)
Nr...Regression curve WF7...Approximate waveform (approximate waveform at the end of the rising edge)
Lr... rising end regression line (rising end approximation line)
Lm: Extension line Tc: Steady period

Claims (20)

a step of measuring a discharge pressure of a discharge device that applies a discharge pressure to a treatment liquid to discharge the treatment liquid from a nozzle during an evaluation period that includes at least a main period from when the discharge pressure starts to increase to a predetermined pressure until when the discharge pressure starts to decrease from the predetermined pressure;
extracting a feature quantity of the change in the discharge pressure over time throughout the evaluation period as an overall feature quantity;
evaluating a time change of the ejection pressure based on the overall characteristic amount ,
the evaluation period is the main period,
a main feature quantity, which is a feature quantity possessed by the time change of the discharge pressure throughout the main period, is extracted as the overall feature quantity;
the main characteristic amount indicates a difference between a main approximate waveform that approximates the time change of the discharge pressure over the entire main period and the time change of the discharge pressure over the entire main period;
The main approximation waveform is
a rising approximation line that linearly approximates a time change in the ejection pressure that increases with time after the start of ejection of the treatment liquid from the nozzle, and that linearly increases with time from the ejection start pressure to a steady pressure that is greater than the ejection start pressure;
a start approximation line that indicates the ejection start pressure and is provided between the start point of ejection of the treatment liquid from the nozzle and the rising approximation line;
a steady line indicating the steady pressure, which is provided between the time when the rising approximation line reaches the steady pressure and the end of the main period;
A discharge pressure evaluation method comprising : a step of measuring a discharge pressure of a discharge device that applies a discharge pressure to a treatment liquid to discharge the treatment liquid from a nozzle during an evaluation period that includes at least a main period from when the discharge pressure starts to increase to a predetermined pressure until when the discharge pressure starts to decrease from the predetermined pressure;
extracting a feature quantity of the change in the discharge pressure over time throughout the evaluation period as an overall feature quantity;
evaluating a time change of the ejection pressure based on the overall characteristic amount ,
the evaluation period is a first period from when the discharge of the treatment liquid from the nozzle starts to when the discharge of the treatment liquid from the nozzle ends,
a first feature quantity that is a feature quantity possessed by the time change of the discharge pressure throughout the first period is extracted as the overall feature quantity;
the first characteristic amount indicates a difference between a first approximate waveform that approximates the time change of the discharge pressure over the entire first period and the time change of the discharge pressure over the entire first period;
The first approximate waveform is
a rising approximation line that linearly increases with time from the ejection start pressure to a steady pressure that is greater than the ejection start pressure by linearly approximating the time change of the ejection pressure that increases with time after the ejection of the treatment liquid from the nozzle starts;
a start approximation line that indicates the ejection start pressure and is provided between the start point of ejection of the treatment liquid from the nozzle and the rising approximation line;
a falling approximation line that linearly approximates a time change in the discharge pressure that decreases over time before the discharge of the treatment liquid from the nozzle is completed, and that linearly decreases over time from the steady pressure to a discharge completion pressure that is smaller than the steady pressure;
an end-time approximation line that is provided between the falling approximation line and the end point of the discharge of the treatment liquid from the nozzle and indicates the discharge end pressure;
A steady line indicating the steady pressure is formed by connecting the rising approximation line and the falling approximation line.
A discharge pressure evaluation method comprising : a step of measuring a discharge pressure of a discharge device that applies a discharge pressure to a treatment liquid to discharge the treatment liquid from a nozzle during an evaluation period that includes at least a main period from when the discharge pressure starts to increase to a predetermined pressure until when the discharge pressure starts to decrease from the predetermined pressure;
extracting a feature quantity of the change in the discharge pressure over time throughout the evaluation period as an overall feature quantity;
evaluating a time change of the ejection pressure based on the overall characteristic amount ;
extracting, as a second feature amount, a feature amount possessed by a time change of the discharge pressure during a second period shorter than the evaluation period within the evaluation period;
Equipped with
a discharge pressure evaluation method for evaluating a change in the discharge pressure over time based on the overall characteristic amount and the second characteristic amount ; a predetermined initial rise period from the start of ejection of the treatment liquid from the nozzle is set as the second period;
During the initial rise period, the discharge pressure increases over time,
The discharge pressure evaluation method according to claim 3 , wherein a feature value indicating a difference between a regression curve of the time change of the discharge pressure in the initial rise period and the time change of the discharge pressure in the initial rise period is extracted as the second feature value. 5. The discharge pressure evaluation method according to claim 3, wherein a rise period from when the discharge of the treatment liquid from the nozzle starts until the discharge pressure increases to the predetermined pressure is set as the second period. The discharge pressure evaluation method according to claim 5 , wherein the length of the rise period is extracted as the second characteristic amount. 7. The discharge pressure evaluation method according to claim 5 , wherein the number of times that a first-order differential of the change in the discharge pressure with respect to time crosses a predetermined threshold value during the rise period is extracted as the second characteristic amount. The discharge pressure evaluation method according to claim 5 , wherein the number of times that an absolute value of a second-order differential of the time change of the discharge pressure crosses a predetermined threshold during the rise period is extracted as the second characteristic amount. 9. The discharge pressure evaluation method according to claim 5, wherein the ratio of the time during the rise period during which the second derivative of the time change of the discharge pressure becomes greater than a predetermined positive threshold to the time during which the second derivative of the time change of the discharge pressure becomes smaller than a predetermined negative threshold having the same absolute value as the positive threshold is extracted as the second characteristic quantity. a predetermined rise end period until the discharge pressure increases to the predetermined pressure is set as the second period,
a feature quantity indicating a difference between a rise end approximation waveform that approximates the time change of the discharge pressure in the rise end period and the time change of the discharge pressure in the rise end period is extracted as the second feature quantity;
The rising end approximation waveform is
a rise end approximation line that overlaps with an approximation curve obtained by linearly approximating the time change of the discharge pressure that increases with time in a pressure range smaller than the predetermined pressure, and that linearly increases with time to a steady pressure that is an average value of the time change of the discharge pressure in a steady period after the rise end period;
The discharge pressure evaluation method according to claim 3 , further comprising an extended line indicating the steady-state pressure, the extended line extending from the rise end approximation line to an end point of the rise end period. an initial vibration period from when the discharge pressure reaches a maximum value to when the second derivative of the time change of the discharge pressure crosses zero twice is set as the second period;
A discharge pressure evaluation method according to any one of claims 3 to 10, wherein the difference between the smaller of the minimum value of the discharge pressure during the initial vibration period and the average value of the discharge pressure during a predetermined steady period after the initial vibration period and the maximum value of the discharge pressure is extracted as the second characteristic. a predetermined transition period from the time when the discharge pressure exceeds the predetermined pressure is set as the second period;
A discharge pressure evaluation method according to any one of claims 3 to 11 , wherein a feature indicating the difference between the discharge pressure during the transition period and the average value of the discharge pressure during a predetermined steady period after the transition period is extracted as the second feature. a constant pressure period from when the discharge pressure exceeds the predetermined pressure to when the discharge pressure starts to decrease toward the end of discharge of the treatment liquid from the nozzle is set as the second period;
The discharge pressure evaluation method according to claim 3 , wherein a feature value indicating a difference between a maximum value and a minimum value of the discharge pressure during the constant pressure period is extracted as the second feature value. a step of measuring a discharge pressure of a discharge device that applies a discharge pressure to a treatment liquid to discharge the treatment liquid from a nozzle during an evaluation period that includes at least a main period from when the discharge pressure starts to increase to a predetermined pressure until when the discharge pressure starts to decrease from the predetermined pressure;
extracting a feature quantity of the change in the discharge pressure over time throughout the evaluation period as an overall feature quantity;
evaluating a time change of the ejection pressure based on the overall characteristic amount ;
the evaluation period is the main period,
a main feature quantity, which is a feature quantity possessed by the time change of the discharge pressure throughout the main period, is extracted as the overall feature quantity;
the main characteristic amount indicates a difference between a main approximate waveform that approximates the time change of the discharge pressure over the entire main period and the time change of the discharge pressure over the entire main period;
The main approximation waveform is
a rising approximation line that linearly approximates a time change in the ejection pressure that increases with time after the start of ejection of the treatment liquid from the nozzle, and that linearly increases with time from the ejection start pressure to a steady pressure that is greater than the ejection start pressure;
a start approximation line that indicates the ejection start pressure and is provided between the start point of ejection of the treatment liquid from the nozzle and the rising approximation line;
a steady line indicating the steady pressure, which is provided between the time when the rising approximation line reaches the steady pressure and the end of the main period;
A discharge pressure evaluation program having : a step of measuring a discharge pressure of a discharge device that applies a discharge pressure to a treatment liquid to discharge the treatment liquid from a nozzle during an evaluation period that includes at least a main period from when the discharge pressure starts to increase up to a predetermined pressure until when the discharge pressure starts to decrease from the predetermined pressure;
extracting a feature quantity of the change in the discharge pressure over time throughout the evaluation period as an overall feature quantity;
evaluating a time change of the ejection pressure based on the overall characteristic amount ;
the evaluation period is a first period from when the discharge of the treatment liquid from the nozzle starts to when the discharge of the treatment liquid from the nozzle ends,
a first feature quantity that is a feature quantity possessed by the time change of the discharge pressure throughout the first period is extracted as the overall feature quantity;
the first characteristic amount indicates a difference between a first approximate waveform that approximates the time change of the discharge pressure over the entire first period and the time change of the discharge pressure over the entire first period;
The first approximate waveform is
a rising approximation line that linearly increases with time from the ejection start pressure to a steady pressure that is greater than the ejection start pressure by linearly approximating the time change of the ejection pressure that increases with time after the ejection of the treatment liquid from the nozzle starts;
a start approximation line that indicates the ejection start pressure and is provided between the start point of ejection of the treatment liquid from the nozzle and the rising approximation line;
a falling approximation line that linearly approximates a time change in the discharge pressure that decreases over time before the discharge of the treatment liquid from the nozzle is completed, and that linearly decreases over time from the steady pressure to a discharge completion pressure that is smaller than the steady pressure;
an end-time approximation line that is provided between the falling approximation line and the end point of the discharge of the treatment liquid from the nozzle and indicates the discharge end pressure;
A steady line indicating the steady pressure is formed by connecting the rising approximation line and the falling approximation line.
A discharge pressure evaluation program having : a step of measuring a discharge pressure of a discharge device that applies a discharge pressure to a treatment liquid to discharge the treatment liquid from a nozzle during an evaluation period that includes at least a main period from when the discharge pressure starts to increase to a predetermined pressure until when the discharge pressure starts to decrease from the predetermined pressure;
extracting a feature quantity of the change in the discharge pressure over time throughout the evaluation period as an overall feature quantity;
evaluating a time change of the ejection pressure based on the overall characteristic amount ;
extracting, as a second feature amount, a feature amount possessed by a time change of the discharge pressure during a second period shorter than the evaluation period within the evaluation period;
on the computer ,
a discharge pressure evaluation program for evaluating a change over time in the discharge pressure based on the overall characteristic amount and the second characteristic amount ; A recording medium for recording the discharge pressure evaluation program according to any one of claims 14 to 16 in a computer-readable manner. A nozzle;
a pressure applying unit that applies a discharge pressure to the treatment liquid to discharge the treatment liquid from the nozzle;
a measurement unit for measuring the discharge pressure;
a control unit that acquires the discharge pressure measured by the measurement unit during an evaluation period that includes at least a main period from when the discharge of the treatment liquid from the nozzle starts, through when the discharge pressure increases to a predetermined pressure, until when the discharge pressure starts to decrease from the predetermined pressure,
the control unit extracts a feature quantity possessed by the time change of the discharge pressure throughout the entire evaluation period as an overall feature quantity, and evaluates the time change of the discharge pressure based on the overall feature quantity;
the evaluation period is the main period,
a main feature quantity, which is a feature quantity possessed by the time change of the discharge pressure throughout the main period, is extracted as the overall feature quantity;
the main characteristic amount indicates a difference between a main approximate waveform that approximates the time change of the discharge pressure over the entire main period and the time change of the discharge pressure over the entire main period;
The main approximation waveform is
a rising approximation line that linearly approximates the time change of the discharge pressure that increases with time after the start of discharge of the treatment liquid from the nozzle, and that linearly increases with time from the discharge start pressure to a steady pressure that is greater than the discharge start pressure;
a start approximation line that indicates the ejection start pressure and is provided between the start point of ejection of the treatment liquid from the nozzle and the rising approximation line;
a steady line indicating the steady pressure, which is provided between the time when the rising approximation line reaches the steady pressure and the end of the main period;
A substrate processing apparatus having : A nozzle;
a pressure applying unit that applies a discharge pressure to the treatment liquid to discharge the treatment liquid from the nozzle;
a measurement unit for measuring the discharge pressure;
a control unit that acquires the discharge pressure measured by the measurement unit during an evaluation period that includes at least a main period from when the discharge of the treatment liquid from the nozzle starts, through when the discharge pressure increases to a predetermined pressure, until when the discharge pressure starts to decrease from the predetermined pressure,
the control unit extracts a feature quantity possessed by the time change of the discharge pressure throughout the entire evaluation period as an overall feature quantity, and evaluates the time change of the discharge pressure based on the overall feature quantity;
the evaluation period is a first period from when the discharge of the treatment liquid from the nozzle starts to when the discharge of the treatment liquid from the nozzle ends,
a first feature quantity that is a feature quantity possessed by the time change of the discharge pressure throughout the first period is extracted as the overall feature quantity;
the first characteristic amount indicates a difference between a first approximate waveform that approximates the time change of the discharge pressure over the entire first period and the time change of the discharge pressure over the entire first period;
The first approximate waveform is
a rising approximation line that linearly increases with time from the ejection start pressure to a steady pressure that is greater than the ejection start pressure by linearly approximating the time change of the ejection pressure that increases with time after the ejection of the treatment liquid from the nozzle starts;
a start approximation line that indicates the ejection start pressure and is provided between the start point of ejection of the treatment liquid from the nozzle and the rising approximation line;
a falling approximation line that linearly approximates a time change in the discharge pressure that decreases over time before the discharge of the treatment liquid from the nozzle is completed, and that linearly decreases over time from the steady pressure to a discharge completion pressure that is smaller than the steady pressure;
an end-time approximation line that is provided between the falling approximation line and the end point of the discharge of the treatment liquid from the nozzle and indicates the discharge end pressure;
A steady line indicating the steady pressure is formed by connecting the rising approximation line and the falling approximation line.
A substrate processing apparatus having : A nozzle;
a pressure applying unit that applies a discharge pressure to the treatment liquid to discharge the treatment liquid from the nozzle;
a measurement unit for measuring the discharge pressure;
a control unit that acquires the discharge pressure measured by the measurement unit during an evaluation period that includes at least a main period from when the discharge of the treatment liquid from the nozzle starts, through when the discharge pressure increases to a predetermined pressure, until when the discharge pressure starts to decrease from the predetermined pressure,
The control unit extracts a characteristic quantity possessed by the time change of the discharge pressure throughout the entire evaluation period as an overall characteristic quantity, extracts a characteristic quantity possessed by the time change of the discharge pressure during a second period of the evaluation period that is shorter than the evaluation period as a second characteristic quantity, and evaluates the time change of the discharge pressure based on the overall characteristic quantity and the second characteristic quantity .