JP2008177386A - Cleaning apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning apparatus that detects a wafer on which failures such as inadequate cleaning occurs and that determines chemical supply time, in a cleaning process where rise time to make flow rate stable accounts for a half or more of the chemical supply time. <P>SOLUTION: The cleaning apparatus includes: a flow meter provided on a supply line for supplying a chemical to an ejecting section for the wafer; a control section for transmitting signals for opening a valve on the supply line; a means for obtaining an integral value of a chemical flow rate in a predetermined period after the signal is transmitted based on the measurement result of the flow meter; and a warning means for warning about the cleaning of the wafer if the obtained integral value is out of a range of a predetermined reference to the integral value of the chemical flow rate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for measuring the flow rate of a fluid such as a chemical solution and evaluating the cleaning performance of a substrate in a process of cleaning a semiconductor wafer or the like using a chemical solution or pure water.

  In a technology for cleaning a substrate such as a semiconductor wafer using a chemical solution or the like, there is a method of monitoring the flow rate of the chemical solution and issuing an alarm when the flow rate decreases or increases.

The method described in Patent Document 1 will be described with reference to FIG. When supplying a chemical solution to a plurality of wet etching apparatuses, a chemical solution supply line 102 is connected to the etching processing tank 101, and supply to the etching processing tank 101 is controlled by a valve 103. The chemical flow rate is measured using the flow meters 104 and 105 installed in the supply line 102, and the data of the respective flow meters 104 and 105 is transferred to the comparison / determination circuit 108 through the signal lines 106 and 107. Data is transferred from the comparison / determination circuit 108, and the monitor 109 displays the chemical flow rate and usage amount of each wet etching apparatus. The flow rate is monitored by the comparison / judgment circuit 108, and the time during which the chemical solution flows is compared with a predetermined standard width and determined. When the chemical solution is flowing beyond the standard width, an alarm is issued. .
Japanese Patent No. 3093519

  However, with the recent miniaturization, it is necessary to shorten the time for supplying the chemical solution due to the thickness of the material to be etched being reduced. In some cases, the ratio of the rising period until the flow rate is stabilized after the chemical solution is charged to the chemical supply time is more than half. In such a case, the variation in the rising profile of the chemical flow rate greatly affects the etching amount and the cleaning performance. Due to the difference in the opening / closing timing of the valve of the chemical liquid line and the fluctuation of the chemical supply pressure, the time until the chemical liquid flow rate is stabilized varies, and there is a concern that this variation may deteriorate the cleaning performance.

  The conventional technology does not take into account the variation in the period until the flow rate is stabilized after the chemical solution is introduced, and the cleaning time is high, and the time until the flow rate becomes stable is high in the chemical solution supply time. In the case of the method, there is a problem that the period during which the flow rate of the chemical solution rises cannot be monitored. Furthermore, in the prior art, it is possible to detect the shortage and waste of the chemical solution, but it is not possible to stabilize the cleaning performance.

  In the present invention, an integrated value of the flow rate in the chemical solution supply time is calculated and monitored by using a cleaning device equipped with a flow meter in the chemical solution supply line and a monitoring tool for collecting the measured values. An error band is set, and an alarm is issued when the error band comes off.

  Furthermore, the instantaneous flow rate may be monitored together and an alarm may be issued if the flow rate error band is not met. This is because only the monitoring of the integral value lowers the detection capability for a temporary increase or drop in the flow rate within a very short time. A temporary increase or drop in the flow rate leads to deterioration in the uniformity of the etching amount on the surface of the wafer to be cleaned, and deteriorates the cleaning performance. This can be detected by monitoring the instantaneous flow rate.

  Further, a differential value is calculated from the measured flow rate value, and the flow rate change amount at the rising and steady state is monitored. Detection at the end of the rising period, detection at the end of the chemical discharge period, and temporary increase or decrease in flow rate when the flow rate is stable can be detected.

  The differential value of the chemical liquid flow rate may be monitored in accordance with the monitoring of the integral value described above, or the instantaneous flow rate may be monitored when the flow rate is stabilized in addition to the differential value monitoring.

  Furthermore, using the integrated value of the chemical flow rate as an end point for determining the chemical supply time, and supplying the chemical solution until the integrated value reaches a certain set value, the chemical solution is introduced and the rising period until the flow rate becomes stable Even in a situation where variations occur, the same amount of chemical solution is always discharged to the wafer, so that the cleaning performance can be stabilized.

  As in the present invention, by calculating the integral value or differential value of the chemical flow rate value and using it for monitoring, even when the cleaning time during which the chemical solution is discharged to the wafer is short, the rising period of the chemical flow rate is included. The flow rate can be monitored. In addition, even with respect to variations such as rising timing, the same amount of chemical solution is discharged onto the wafer by taking the end point with an integral value, so that a stable cleaning effect is always obtained.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described. In the present embodiment, the flow rate of the chemical solution discharged to the substrate to be cleaned is measured and constantly monitored.

  A cleaning mechanism in the present embodiment is shown in FIG. In this cleaning mechanism, a chemical solution is discharged onto the front surface and the back surface of the substrate 11 through the chemical solution line 12 with respect to the rotated substrate 11. Flow lines 13 and 14 are provided on the lines discharged to the front and back surfaces of the base 11, respectively, and the flow rate value measured by the monitoring tool 16 connected to the flow meters 13 and 14 is constantly monitored. The chemical liquid line 12 is provided with a valve 15 to control the discharge timing of the chemical liquid to the base 11. The time for opening the valve 15 is set in advance under the condition for cleaning the substrate 11, and a signal is given from the control unit 17 to the valve 15 according to the set time, and the chemical solution is discharged from the discharge units 18 and 19 to the substrate 11.

  FIG. 2 shows an example of data acquired by the flow meter 13 when the base 11 is washed with the configuration of FIG. In the flow rate profile 21 with respect to the elapsed time, a rising period 23, a steady period 24, and a falling period 25 continue after a period 22 from when the signal for opening the valve 15 of the chemical liquid line 12 is issued until the chemical liquid actually flows out. The flow rate becomes zero. The rising period 23 is the time required for the chemical liquid to flow and reach the set flow rate, and the steady period 24 is the period from the chemical liquid flow rate reaching the set flow rate until the valve 15 is closed, and the falling period Reference numeral 25 denotes a period from when the valve 15 is closed until the flow rate of the chemical solution decreases to 0.

  The lengths of these periods 22 to 25 vary depending on the supply status of the chemical solution. The length of the period 22 from when the valve 15 is opened to when the chemical solution flows out varies depending on the timing at which the valve 15 is opened and the supply pressure of the chemical solution varies. The length of the rising period 23 changes due to variations in the opening of the valve 15 and fluctuations in the supply pressure of the chemical solution. The steady period 24 changes as the rising period 23 changes. If the rising period 23 becomes longer, it becomes shorter, and if the rising period 23 becomes shorter, it becomes longer. The falling period 25 changes due to variations in timing at which the valve 15 is closed.

  With the recent miniaturization in the semiconductor manufacturing process, it is necessary to reduce the etching amount and ensure reproducibility in the technique of cleaning the base surface and back surface oxide films with a chemical solution such as HF. Furthermore, the thickness of the oxide film formed on the front surface or the back surface is becoming thinner, and there is a concern about damage to the non-etched film during the conventional etching time. For this reason, there is a need to shorten the etching time, that is, the chemical treatment time. The chemical treatment time that has been about 30 seconds or more in the past is about 10 seconds. As shown in FIG. It accounts for about half of the processing time.

  Furthermore, as described above, the rising period 23 changes due to variations in the opening of the valve 15 or fluctuations in the supply pressure of the chemical solution. FIG. 3 shows three flow rate profiles 31 to 33 having different rising periods. In contrast to the normal flow rate profile 31, the flow rate profile 32 has an early rise because the timing at which the valve 15 opens is early or the supply pressure of the chemical solution is high. In the flow rate profile 33, the rise of the valve 15 is delayed because the opening timing of the valve 15 is late or the supply pressure of the chemical solution is low.

  As described above, when the chemical solution processing time is shortened and the rising period 23 occupies about half of the rising time 23, the change in the rising period 23 leads to the fluctuation of the total amount of the chemical discharged to the base 11, and the oxidation of the front and back surfaces of the base 11 The etching amount of the film fluctuates and the cleaning performance varies.

  Therefore, it is impossible to detect when the cleaning performance is deteriorated only by monitoring the flow rate value after the chemical flow rate has reached the set flow rate as in the prior art. To solve this problem, there are a method in which the chemical solution concentration is reduced to increase the chemical solution processing time, and a method in which the chemical solution flow rate is decreased to increase the chemical solution processing time.

  However, if the chemical solution processing time is lengthened, it affects the processing capability of the cleaning apparatus itself, and cannot meet the recent demands for shortening the processing time and product lead time. Moreover, about the method of reducing a chemical | medical solution flow rate, there exists a possibility that a chemical | drug | medicine cannot be uniformly supplied to the surface of the base | substrate 11 or the whole back surface, and there exists a possibility that cleaning performance may fall as a result. In order to achieve both product lead time and cleaning performance, a chemical supply time of a certain time or less, a chemical concentration and a chemical flow rate of a certain value or more are required.

  In this embodiment, when the rising period 23 has a large influence on the cleaning result of the base 11 such as when the rising period 23 occupies about half of the chemical solution processing time, the integrated value of the chemical flow rate is calculated and the integrated value is calculated. On the other hand, when the preset upper limit of the reference value is exceeded or falls below the lower limit of the reference value, the cleaned substrate is identified and an alarm is issued. The calculation of the integral value and the warning are performed by the monitoring tool 16 in FIG. You may install the unit for that separately. The alarm may be output on the display screen or may be output as a notification sound.

  As the period for calculating the integral value, the period 41 in FIG. 4 or the period 51 in FIG. 5 can be employed. The period 41 is a period for supplying a chemical solution set in advance under the condition for cleaning the base 11, and the valve is open during this period. The monitoring tool 16 can specify this period 41 from the control signal for opening and closing the valve 15. Further, the period 51 is a period from when the chemical liquid actually flows out until the flow rate of the chemical liquid becomes zero. The monitoring tool 16 can determine the period 51 from the value of the chemical flow rate obtained by the flow meters 13 and 14. In order to accurately grasp and monitor the total amount of the chemical liquid discharged to the base 11, it is better to integrate the chemical liquid flow rate for the period 51.

As described above, in this embodiment, by using the integral value of the chemical liquid flow rate, monitoring including the rising period of the chemical liquid flow rate is possible, and the base when the base cleaning performance is reduced can be extracted with high accuracy.
(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described. Also in this embodiment, the cleaning mechanism of FIG. 1 can be used.

  FIG. 6 shows an example of a chemical flow rate profile when a problem occurs during chemical supply. In the first embodiment described above, the flow rate may be suddenly disturbed during a steady period in which a set amount of the chemical solution flows, for example, due to some trouble that occurred during the supply of the chemical solution. When such a chemical flow rate profile is obtained, even if the calculated integral value is within the preset reference range, the cleaning performance cannot be ensured because the discharge state of the chemical to the base is different from normal. there is a possibility.

  In the present embodiment, the monitoring tool 16 calculates an integrated value of the chemical flow rate, and identifies the substrate that has been cleaned when the integrated value exceeds a preset reference value upper limit or falls below the reference value lower limit. In addition to alarming, in the preset period, the washed base is also used when the flow rate value obtained by the flow meters 13 and 14 exceeds the preset reference value upper limit 61 or falls below the reference value lower limit 62. Identify and issue an alarm.

  The period during which the flow rate value is monitored can be set arbitrarily during the chemical processing, but it is necessary to set it after providing a delay time that takes into account the rising period of the chemical flow rate. For example, it is monitored whether or not the flow rate value is within the range of the reference value after the delay time from the opening of the valve 15 until the estimated rise period elapses.

By monitoring the flow rate value in addition to the chemical flow rate integral value, it is possible to detect sudden flow fluctuations that do not appear in the difference in the integral value, thereby more reliably reducing the base cleaning performance. Can be extracted.
(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described. Also in this embodiment, the cleaning mechanism of FIG. 1 can be used. In this embodiment, the monitoring tool 16 calculates the differential value of the chemical flow rate instead of or in addition to the integral value of the chemical flow rate. A separate unit may be installed to calculate the differential value.

  FIG. 7 shows an example of the profile of the differential value of the chemical liquid flow rate. This profile corresponds to the chemical flow rate profile shown in FIG. The time point 71 at which the chemical solution flows out is a time point when the differential value profile first steeply rises. At the time 72 when the chemical flow rate reaches the set flow rate and the rising period ends, the differential value of the chemical flow rate returns to zero. From the time point 73 when the valve 15 is closed, the differential value of the chemical flow rate rapidly decreases. At the time point 74 when the chemical liquid flow rate disappears and the falling period ends, the differential value of the chemical liquid flow rate returns to 0 again.

  That is, in the rising period 75 from when the chemical solution starts to reach the set flow rate, the differential value of the chemical solution flow rate shows a positive value, and the steady period 76 from when the chemical solution flow rate reaches the set flow rate until the valve 15 is closed. Then, the differential value of the chemical liquid flow rate becomes almost zero, and the value of the chemical liquid flow rate shows a negative value in the falling period 77 from when the valve 15 is closed until the chemical liquid flow rate becomes zero.

  In this embodiment, the monitoring tool 16 calculates a time differential value of the chemical liquid flow rate for a period from when the valve 15 is opened until the chemical flow rate becomes zero, and based on the calculated differential value, a rising period 75, A steady period 76 and a falling period 77 are determined. The monitoring tool 16 compares the reference value upper limit and the reference value lower limit set in advance for each of these periods with the determined lengths of the periods 75 to 77, and the length of the periods 75 to 77 exceeds the reference value upper limit. When the value falls below the lower limit of the reference value, the washed base is identified and an alarm is issued. The periods 75 to 77 can be determined by a threshold with respect to the differential value of the chemical liquid flow rate, or can be determined by obtaining a secondary differential value.

  When the length of the rising period 75 of the chemical liquid flow rate exceeds the preset reference value upper limit, the rising of the chemical liquid flow rate is slow. On the other hand, when the length of the rising period 75 falls below the preset reference value lower limit, the rising of the chemical flow rate is quick. In either case, there is a concern that the cleaning performance of the base cannot be secured because the total amount of the chemical solution with respect to the base changes.

  In addition, when the length of the steady period 76 in which the chemical liquid at the set flow rate exceeds the preset reference value upper limit, the discharge time of the chemical liquid at the set flow rate is long. Conversely, when the length of the steady period 76 is less than the preset reference value lower limit, the discharge time of the chemical solution at the set flow rate is short. In either case, there is a concern that the cleaning performance of the base cannot be secured because the total amount of the chemical solution with respect to the base changes.

  Further, when the length of the falling period 77 of the chemical liquid flow rate exceeds the preset reference value upper limit, the falling of the chemical liquid flow rate is delayed. Conversely, when the length of the falling period 77 falls below a preset reference value lower limit, the falling of the chemical liquid flow rate is quick. In either case, there is a concern that the cleaning performance of the base cannot be secured because the total amount of the chemical solution with respect to the base changes.

In this way, it is possible to detect the change in the total amount of chemical liquid discharged to the base by monitoring the length of the rising, steady, and falling periods of the chemical flow from the differential value of the chemical flow. It is possible to accurately extract the base when the cleaning performance is deteriorated.
(Fourth embodiment)
Hereinafter, a fourth embodiment of the present invention will be described. Also in this embodiment, the cleaning mechanism of FIG. 1 can be used. In the fourth embodiment, similarly to the third embodiment, the monitoring tool 16 calculates a differential value of the chemical liquid flow rate instead of or in addition to the integral value of the chemical liquid flow rate. A separate unit may be installed to calculate the differential value.

  In this embodiment, the monitoring tool 16 determines the rising period 75 and the falling period 77 according to the differential value of the chemical liquid flow rate, as in the third embodiment. And the monitoring tool 16 calculates the maximum value 78 of the differential value of the chemical | medical solution flow rate in the rising period 75, and the base | substrate cleaned when the maximum value 78 exceeded the reference value upper limit set beforehand, or fell below the reference value minimum. Is identified and a warning is issued. When the maximum value 78 falls below the reference value lower limit, it is considered that the rising gradient of the chemical liquid flow rate is small, that is, the rising is slow. Conversely, when the maximum value 78 exceeds the upper limit of the reference value, it is considered that the rising gradient of the chemical liquid flow rate is large, that is, the rising is fast. In any case, there is a concern that the cleaning performance of the base cannot be secured because the total amount of the chemical solution with respect to the base changes.

  Similarly, the monitoring tool 16 calculates the minimum value 79 of the differential value in the falling period 77 of the chemical liquid flow rate, and the cleaning is performed when the minimum value 79 exceeds the set reference value upper limit in advance or falls below the reference value lower limit. Can be identified and alarms can be issued. When the minimum value 79 exceeds the upper limit of the reference value, it is considered that the falling gradient of the chemical liquid flow rate is small, that is, the falling is slow. Conversely, when the minimum value 79 falls below the lower limit of the reference value, it is considered that the falling gradient of the chemical liquid flow rate is large, that is, the falling is fast. In either case, there is a concern that the cleaning performance of the base cannot be secured because the total amount of the chemical solution with respect to the base changes.

In this way, by monitoring the base cleaning performance using the differential value of the chemical flow rate, it is possible to detect changes in the total amount of chemical liquid discharged to the base, and the base when the base cleaning performance is reduced can be detected. It can be extracted with high accuracy.
(Fifth embodiment)
Hereinafter, a fifth embodiment of the present invention will be described. Also in this embodiment, the cleaning mechanism of FIG. 1 can be used. In the fifth embodiment, similarly to the third and fourth embodiments, the monitoring tool 16 calculates a differential value of the chemical liquid flow rate instead of or in addition to the integral value of the chemical liquid flow rate. A separate unit may be installed to calculate the differential value.

  In this embodiment, the monitoring tool 16 determines the rising period, the steady period, and the falling period of the chemical liquid flow rate based on the differential value of the chemical liquid flow rate, as in the third embodiment. These periods may be determined by, for example, a zero cross method using a secondary differential value. Further, the monitoring tool 16 can issue an alarm for the rising period and the falling period in the same manner as in the third embodiment or the fourth embodiment. For the steady period, the monitoring tool 16 identifies the washed base when the value of the chemical flow rate obtained by the flow meters 13 and 14 exceeds the preset reference value or falls below the reference value lower limit, Raise an alarm.

  FIG. 8 shows a reference width set for a chemical flow rate profile and a chemical flow rate value. In the conventional monitoring only of the chemical liquid flow rate, it is necessary to shorten the time for monitoring the flow rate or widen the reference width due to variations in the timing at which the valve of the chemical liquid line opens and variations in the rising period 81 of the chemical liquid flow rate. . In this embodiment, since the rising end of the chemical flow rate can be accurately extracted based on the differential value of the chemical flow rate, it is necessary to consider such variation in the reference width 84 of the chemical flow rate set for the steady period 82. Absent. For this reason, it is possible to monitor the entire period in which the set flow rate is discharged to the substrate, and the monitoring width 84 can be narrowed to a level that can ensure a desired cleaning performance.

In this way, the rising end time and the falling start time of the chemical liquid flow rate are extracted with high accuracy from the differential value of the chemical liquid flow rate, the steady period during which the set flow rate is discharged is determined, and the chemical liquid flow rate is monitored during the steady period. As a result, the base when the cleaning performance is reduced can be extracted with high accuracy.
(Sixth embodiment)
Hereinafter, a sixth embodiment of the present invention will be described. Also in this embodiment, the cleaning mechanism of FIG. 1 can be used. In the sixth embodiment, the monitoring tool 16 obtains an integrated value of the chemical flow rate and calculates a differential value of the chemical flow rate. A separate unit may be installed for calculating the integral value and the differential value.

  In the first embodiment, the integration period for calculating the integral value of the chemical liquid flow rate is obtained from the value of the chemical liquid flow rate. In the sixth embodiment, the monitoring tool 16 calculates a differential value of the chemical liquid flow rate as in the third embodiment, and based on the differential value, the time point 71 at which the chemical liquid flows out in FIG. The end point 74 is extracted. Then, the monitoring tool 16 determines a period from the time point 71 when the chemical solution flows out to the end point 74 of the fall as a calculation period of the integral value of the chemical solution flow rate, and obtains the integrated value of the chemical solution flow rate. In accordance with the integrated value of the chemical flow rate, an alarm is issued in the same manner as in the first embodiment.

By using the differential value of the chemical liquid flow rate in this way, it is possible to accurately detect the period during which the chemical liquid is actually discharged to the base, and the accuracy of calculating the total amount of chemical discharged to the base is improved. . As a result, it is possible to more reliably extract the base when the base cleaning performance is deteriorated.
(Seventh embodiment)
The seventh embodiment of the present invention will be described below. Also in this embodiment, the cleaning mechanism of FIG. 1 can be used. In the seventh embodiment, the monitoring tool 16 calculates the integral value of the chemical liquid flow rate as in the first embodiment and the sixth embodiment. The integral value is calculated every time the sampling time elapses after the valve 15 is opened, for example. Further, the control unit 17 gives a signal for closing the valve 15 based on the integrated value of the chemical flow rate obtained by the monitoring tool 16 and a reference value predetermined for the integrated value of the chemical flow rate. The integration value and the reference value are also compared at each sampling time. And the control part 17 discharges a chemical | medical solution until the integral value of a chemical | medical solution flow volume reaches the reference value. When the integral value of the chemical flow rate calculated sequentially reaches the reference value, the valve 15 is closed.

  FIG. 9 shows the profile of the chemical flow rate and the timing for closing the valve. If the normal chemical solution rises, the valve 15 is closed at a point 91 when the reference value is reached. Even when the rise of the valve 15 is delayed due to a delay in the opening timing, the chemical solution is discharged to the base until the reference value is reached, and the valve 15 is closed when the reference value is reached 92.

  In this way, by using the integrated value of the chemical flow rate as the end point of the chemical solution supply time and discharging the chemical solution up to a preset reference value, a constant amount of chemical solution is always supplied regardless of variations in the rise timing of the chemical flow rate. The substrate can be discharged and the same cleaning result can always be ensured.

  Furthermore, by using the method for determining the chemical solution supply time of the present invention as an end point program and a recording medium, the end point can be detected according to the type and process.

  The cleaning apparatus according to the present invention measures the flow rate of the chemical solution and evaluates the result of the cleaning process using the integral value or differential value of the flow rate. This is useful as an endpoint function that determines the detection time and chemical solution supply time.

Configuration diagram of cleaning equipment Diagram showing an example of chemical flow rate profile The figure which shows the example of the chemical | medical solution flow rate profile when dispersion | variation generate | occur | produces in the rising of a chemical | medical solution flow rate The figure which shows an example of the chemical | medical solution flow rate profile at the time of setting the period which supplies the chemical | medical solution set beforehand as the integration period of chemical | medical solution flow rate The figure which shows an example of a chemical | medical solution flow rate profile at the time of setting it as the integration period of a flow volume from the rising start time of a chemical | medical solution flow rate to the end point of falling of a chemical | medical solution The figure which shows an example of the chemical | medical solution flow rate profile when sudden fluctuation | variation generate | occur | produces in a chemical | medical solution flow rate The figure which shows an example of the differential value profile of a chemical | medical solution flow rate Diagram showing an example of chemical flow profile and flow error band setting The figure which shows the example of the chemical | medical solution flow rate profile at the time of supplying a chemical | medical solution until the integral value of a chemical | medical solution flow rate reaches | attains a reference value Configuration diagram of conventional cleaning equipment

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Base 12 Chemical solution supply line 13 Chemical solution line flow meter 14 supplied to the substrate surface Chemical solution line flow meter 15 supplied to the substrate back surface Valve 16 Monitoring tool 17 Control unit 18 Discharge unit 19 for the chemical solution to the substrate surface Discharge part

Claims (7)

A flow meter provided in the supply line for supplying the chemical to the discharge part to the base,
A control unit for providing a signal for opening a valve on the supply line;
Based on the measurement result of the flow meter, means for obtaining an integral value of the chemical liquid flow rate for a predetermined period after giving the signal;
A cleaning apparatus comprising: a warning unit that issues a warning about cleaning of the base when there is an obtained integrated value outside a predetermined reference range with respect to the integrated value of the chemical liquid flow rate.   2. The cleaning apparatus according to claim 1, wherein the warning means issues the warning even when the chemical flow rate obtained by the flow meter is outside a reference range predetermined for the chemical flow rate. Based on the measurement result of the flow meter, means for obtaining a differential value of the chemical flow rate;
The cleaning apparatus according to claim 1, further comprising: means for determining a start and an end of the predetermined period based on the obtained differential value of the chemical flow rate. A flow meter provided in the supply line for supplying the chemical to the discharge part to the base,
A control unit for providing a signal for opening a valve on the supply line;
Based on the measurement result of the flow meter, means for obtaining a differential value of the chemical flow rate;
Means for determining a rising period, a steady period, and a falling period of the chemical flow rate generated by opening and closing the valve based on the obtained differential value of the chemical flow rate;
If the length of the determined rising period, steady period, or falling period is outside the predetermined reference range with respect to the rising period, steady period, and falling period, a warning is given about cleaning the base. And a cleaning device. A flow meter provided in the supply line for supplying the chemical to the discharge part to the base,
A control unit for providing a signal for opening a valve on the supply line;
Based on the measurement result of the flow meter, means for obtaining a differential value of the chemical flow rate;
Means for determining a rising period and a falling period of the chemical flow rate generated by opening and closing the valve based on the calculated differential value of the chemical flow rate;
When the minimum value or the maximum value of the obtained differential value in the determined rising period or falling period exceeds the reference value determined in advance for the differential value of the liquid flow rate in the rising period and the falling period, A cleaning device comprising means for warning about cleaning of the substrate. A flow meter provided in the supply line for supplying the chemical to the discharge part to the base,
A control unit for providing a signal for opening a valve on the supply line;
Based on the measurement result of the flow meter, means for obtaining a differential value of the chemical flow rate;
Means for determining a steady period from the elapse of the rising period of the chemical flow rate generated by opening and closing of the valve to the start of the falling period, based on the obtained differential value of the chemical flow rate;
A cleaning device comprising: means for giving a warning about cleaning of the base when there is a chemical flow rate obtained by the flow meter outside the reference range predetermined for the chemical flow rate, in a determined steady period. A flow meter provided in the supply line for supplying the chemical to the discharge part to the base,
A control unit for providing a signal for opening a valve on the supply line;
A means for obtaining an integrated value of the chemical flow rate after giving the signal based on the measurement result of the flow meter,
A cleaning device in which the control unit gives a signal for closing the valve based on a reference value predetermined with respect to an integral value of the chemical liquid flow rate and a calculated integral value of the chemical liquid flow rate.

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