Method for determining cleanliness of cleaning member, method for determining adsorption characteristics of contaminants that contaminate cleaning member, method for determining cleanliness of substrate, program for determining cleanliness of substrate, and program for determining end point of cleaning process

Abstract

To provide a contamination degree evaluation method of a new cleaning member that can be applied to improved break-in processing and improved pre-shipment inspection of a cleaning member.SOLUTION: A method for determining the cleanliness of a cleaning member that is in contact with a substrate and performs scrub cleaning measures oscillation frequency of a crystal oscillator before attaching a contaminant on an electrode and records it to a record medium as initial value S50, performs self-cleaning of the cleaning member by discharging contaminant from the cleaning member into cleaning liquid S51, brings drainage after the self-cleaning into contact with the electrode of the crystal oscillator, measures oscillation frequency response of the crystal oscillator where the contaminant is attached onto the electrode after attaching the contaminant contained in the drainage onto the electrode of the crystal oscillator, determines the cleanliness of the cleaning member S52 on the basis of the measured oscillation frequency response, and removes the contaminant from upon the electrode of the crystal oscillator S53.SELECTED DRAWING: Figure 14

Description

Technical Field

[0001] The present disclosure relates to a method for determining the cleanliness of a cleaning member, a method for determining the adsorption characteristics of contaminants that contaminate the cleaning member, and a method for determining the cleanliness of a substrate.

Background Art

[0002] Conventionally, as a method for cleaning the surface of a substrate such as a semiconductor substrate, there is a scrub cleaning method in which a cleaning member made of a brush, a sponge, or the like is rubbed against the surface of the substrate while supplying pure water to the surface of the substrate.

[0003] Generally, after a CMP process in which a substrate is held against a polishing pad and rotated for polishing under a controlled pressure in a state where a CMP slurry containing an abrasive material and a chemical additive is present on the substrate, a substrate cleaning step is performed to remove contaminant particles (often smaller than 0.3 μm) composed of the polishing slurry, chemicals added to the slurry, and particles of reaction by-products of the polishing slurry. Since some contaminants are chemically inert to the chemical components in the cleaning solution, in the substrate cleaning step after the CMP process, in addition to the cleaning step using a chemical solution, a scrub cleaning step is performed to substantially remove residues and contaminants from the substrate surface using a cleaning member composed of a sponge material (such as PVA) having fine pores and configured to have extremely low self-dust generation properties. By the way, this type of scrub cleaning has a high force for removing contaminants attached to the substrate, but on the other hand, since the cleaning member is brought into direct contact with the substrate for cleaning, the cleaning member itself is contaminated, and there is a problem that the cleaning power decreases due to long-term use.

[0004] In addition, when the contamination of the cleaning member progresses, not only does the cleaning power of the substrate decrease, but there is also a problem that the contaminants deposited on the cleaning member reverse-contaminate the substrate and the cleaning effect disappears.

[0005] To avoid these problems, conventionally, methods have been proposed such as supplying a cleaning liquid to a cleaning member and applying ultrasonic vibration to the cleaning liquid (Japanese Patent Application Laid-Open No. 5-317783), cleaning a substrate with a cleaning brush in a cleaning liquid to which ultrasonic vibration is applied (Japanese Patent Application Laid-Open No. 6-5577), rubbing a cleaning member against a contact member in a cleaning liquid to which ultrasonic vibration is applied (Japanese Patent Application Laid-Open No. 10-109074), etc.

[0006] However, although these methods are effective for removing contaminants deposited on the relatively surface layer part of the cleaning member, in a situation where a higher cleaning effect than before is required due to the progress of miniaturization of semiconductor substrates, it is considered that they are not sufficient methods for achieving higher cleanliness by removing contaminants that have entered inside the cleaning member. For example, a method of discharging the cleaning liquid from inside the cleaning member to reduce internal contamination of the cleaning member can be considered, but even this method has problems in realizing a high-level cleaning process throughout the inside of the cleaning member depending on, for example, the distance from the cleaning liquid supply part.

[0007] Conventionally, the quantitative measurement of these contaminants has been carried out by quantitatively evaluating the number of contaminants remaining on the substrate after performing the substrate cleaning process with the cleaning member using a defect inspection device.

[0008] However, for example, if all the substrates after cleaning are evaluated with a defect inspection device, the throughput cannot be improved, and when the substrates are sampled and inspected every predetermined number, timely evaluation becomes difficult. Also, regarding the evaluation method itself, not all the contaminants released from the cleaning member remain on the substrate and are detected. In reality, more contaminants than the number detected on the substrate are released from the cleaning member. Therefore, the conventional method of obtaining the contamination degree of the cleaning member based only on the data of the number of contaminants remaining on the substrate and determining the usability based on that can no longer be said to be a method for judging and estimating cleanliness that can be a judgment index in the future as the progress of miniaturization has required a higher cleaning effect than before.

[0009] In addition, when starting to use a cleaning member such as a new roll cleaning member or a pen cil cleaning member, typically composed of a porous polyvinyl acetal resin, in a substrate cleaning apparatus, in order to prevent defects from occurring in a substrate such as a wafer, it is not possible to directly use the new cleaning member for substrate cleaning, and a break-in process (conditioning process) needs to be performed. In particular, there are wet-type cleaning members that are packaged (stored) in a wet state and then shipped. In this type of wet cleaning member, contamination by various substances such as organic substances, ionic substances, fine particles, and microorganisms has been a problem. Also, even before the product shipment of the cleaning member, it is necessary to reduce contaminants in the substrate cleaning member. In order to improve the substrate cleaning performance during the substrate cleaning process (actual use), it is preferable to evaluate and reduce contaminants that could not be detected by the conventional contamination degree evaluation at the product shipment stage of the cleaning member. That is, there is a need for a new method for evaluating the contamination degree of a cleaning member that can also be applied to an improved break-in process and an improved pre-shipment inspection of the cleaning member.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

[0011] The inventors of the present invention conducted intensive studies to find an improved technique for evaluating the contamination degree of a cleaning member. As a result, the following findings were obtained. Note that the following findings are merely the triggers for the present invention and do not limit the present invention.

[0012] That is, as a method for evaluating the degree of contamination of a cleaning member, it has been sufficient to play a role even with low sensitivity in the past. Rather, when considering the SN ratio (Signal to Noise ratio), it was not always suitable as a method for evaluating the degree of contamination if the analysis sensitivity was too high. However, with the miniaturization of semiconductor substrates, the required level of particle removal in substrate cleaning has become much higher than in the past. Even in a state determined to be "clean" by the conventional analysis method for evaluating the degree of contamination (a state where it was conventionally determined that contaminants were removed), it has been found by the inventor's study that contaminants are eluted in the cleaning liquid. Note that the "contaminants" used in this specification correspond to particles generated in the process of the substrate manufacturing process, which include, but are not limited to, chemical mechanical polishing, wet etching, plasma etching, ashing, and combinations thereof. Also, contaminants remaining on the substrate after chemical mechanical polishing (CMP process) may include chemical substances (such as corrosion inhibitor compounds) present in the slurry, polishing slurry, reaction by-products, polishing pad particles, debris separated from the cleaning member, and any other substances that are by-products of the CMP process. "Contaminants" may include, for example, complexing agents, surfactants, sulfonic acid-containing hydrocarbons, and dispersants.

[0013] Therefore, it is desired to provide a technique that can more accurately determine the cleanliness of the cleaning member. Also, a technique that can more appropriately and quantitatively evaluate the adsorption characteristics of contaminants adhering to the cleaning member is desired. Furthermore, a new method for evaluating the degree of contamination of a cleaning member that can also be applied to improved break-in processing and improved pre-shipment inspection of cleaning members is desired. Also, it is desired to provide a technique that can more timely and accurately determine the cleanliness of the substrate while suppressing a decrease in throughput during cleaning.

[0014] A method according to one aspect of the present disclosure is a method for determining the cleanliness of a cleaning member that contacts a substrate and performs scrub cleaning, a first step of performing self-cleaning of the cleaning member by releasing contaminants from the cleaning member into the cleaning liquid Contact the self-cleaning drain liquid with the electrodes of the crystal oscillator, attach the contaminants contained in the drain liquid to the electrodes of the crystal oscillator, then measure the frequency response of the crystal oscillator with contaminants attached to the electrodes, and determine the cleanliness of the cleaning member based on the measured frequency response. This includes a second step.

Brief Description of the Drawings

[0015]

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Mode for Carrying Out the Invention

[0016] The method according to the first aspect of the embodiment is a method for determining the cleanliness of a cleaning member that scrub-cleans in contact with a substrate, a first step of performing self-cleaning of the cleaning member by releasing contaminants into the cleaning liquid from the cleaning member, a second step of bringing the drainage of the self-cleaning into contact with the electrode of a crystal oscillator, attaching the contaminants contained in the drainage to the electrode of the crystal oscillator, then measuring the vibration frequency response of the crystal oscillator with contaminants attached to the electrode, and determining the cleanliness of the cleaning member based on the measured vibration frequency response.

[0017] According to such an aspect, since the drainage in the self-cleaning of the cleaning member is brought into contact with the electrode of the crystal oscillator, the contaminants contained in the drainage are attached to the electrode of the crystal oscillator, and then the vibration frequency response of the crystal oscillator with contaminants attached to the electrode is measured, it is possible to detect even very minute contaminants, and by determining the cleanliness of the cleaning member based on the measurement result, it is less likely to misjudge a cleaning member with remaining contaminants as "clean", that is, it becomes possible to accurately determine the cleanliness of the cleaning member.

[0018] The method according to the second aspect of the embodiment is the method according to the first aspect, In the first step, in the housing where the scrub cleaning of the substrate is performed, self-cleaning of the cleaning member is performed by releasing contaminants into the cleaning liquid from the cleaning member. In the second step, in the housing, the drainage of the self-cleaning is brought into contact with the electrode of the crystal oscillator, and after the contaminants contained in the drainage are adhered to the electrode of the crystal oscillator, the frequency response of the crystal oscillator with contaminants adhered to the electrode is measured while the crystal oscillator is disposed in the housing, and based on the measured frequency response, the cleanliness of the cleaning member is determined.

[0019] According to such an aspect, after bringing the drainage of the self-cleaning into contact with the electrode of the crystal oscillator and adhering the contaminants contained in the drainage to the electrode of the crystal oscillator, measuring the frequency response of the crystal oscillator with contaminants adhered to the electrode is performed while the crystal oscillator is disposed in the housing where the scrub cleaning of the substrate is performed. Therefore, it is possible to quickly determine the cleanliness of the cleaning member inline, and it is also possible to confirm the change over time of the cleanliness and predict the deterioration replacement timing of the cleaning member based on this.

[0020] The method according to the third aspect of the embodiment is the method according to the first or second aspect, In the second step, after adhering the drainage of the self-cleaning to the electrode of the crystal oscillator and before drying the drainage adhered to the electrode, (a) measure the frequency response of the crystal oscillator, and based on the measured frequency response, measure the liquid volume of the drainage adhered to the electrode, or (b) measure the contact liquid volume with a metering facility for the volume or weight or contact time of the drainage, and then dry the drainage adhered to the electrode to deposit the contaminants contained in the drainage on the electrode of the crystal oscillator, then measure the frequency response of the crystal oscillator, and based on the measured frequency response, measure the amount of contaminants deposited on the electrode, calculate the contaminant concentration of the drainage based on the measured liquid volume and amount of contaminants of the drainage, and determine the cleanliness of the cleaning member based on the calculated contaminant concentration.

[0021] The method according to the fourth aspect of the embodiment is the method according to the first or second aspect, wherein In the second step, a predetermined amount of the drainage of the self-cleaning is attached to the electrode of the crystal oscillator and dried, so that the contaminants contained in the drainage are deposited on the electrode of the crystal oscillator. Then, the frequency response of the crystal oscillator is measured, and based on the measured frequency response, the amount of contaminants deposited on the electrode is measured. Based on the measured amount of contaminants, the cleanliness of the cleaning member is determined.

[0022] The method according to the fifth aspect of the embodiment is the method according to the first or second aspect, wherein In the second step, a crystal oscillator having an adsorption film that adsorbs contaminants by one or both of chemisorption and physisorption fixed on the electrode is immersed in the drainage of the self-cleaning, and after the contaminants contained in the drainage are adsorbed on the adsorption film, the frequency response of the crystal oscillator is measured. Based on the measured frequency response, the amount of contaminants adsorbed on the adsorption film is measured, and based on the measured amount of contaminants, the cleanliness of the cleaning member is determined.

[0023] The method according to the sixth aspect of the embodiment is the method according to the third or fourth aspect, wherein Further includes a third step of immersing a crystal oscillator having contaminants deposited on the electrode in a liquid, measuring the time change of the frequency response of the crystal oscillator, and measuring the mass of the liquid-soluble contaminants based on the difference between the frequency when the time change reaches saturation and the frequency response immediately after immersion in the liquid.

[0024] The method according to the seventh aspect of the embodiment is the method according to the second aspect, wherein Further includes a step of calculating the mass of the liquid-insoluble contaminants based on the difference between the mass of the contaminants deposited on the electrode and the mass of the liquid-soluble contaminants.

[0025] The method according to the eighth aspect of the embodiment is the method according to the sixth or seventh aspect, wherein The liquid is pure water, aqueous ammonia, or an aqueous solution containing a cleaning liquid.

[0026] The method according to the ninth aspect of the embodiment is the method according to any one of the first to eighth aspects, and in the first step, the cleaning member is immersed in the cleaning liquid to release contaminants from the cleaning member into the cleaning liquid.

[0027] The method according to the tenth aspect of the embodiment is the method according to any one of the first to eighth aspects, and in the first step, the cleaning liquid is sprayed toward the surface of the cleaning member to release contaminants from the cleaning member into the cleaning liquid.

[0028] The method according to the eleventh aspect of the embodiment is the method according to any one of the first to eighth aspects, and in the first step, the cleaning liquid flows into the cleaning member and flows out from the surface of the cleaning member, thereby releasing contaminants from the cleaning member into the cleaning liquid.

[0029] The apparatus according to the twelfth aspect of the embodiment is an apparatus for determining the cleanliness of a cleaning member that performs scrub cleaning in contact with a substrate, and a measuring unit that measures the vibration frequency response of a crystal oscillator with contaminants attached to the electrode after contaminants are released from the cleaning member into the cleaning liquid, the cleaning liquid containing the contaminants is brought into contact with the electrode of the crystal oscillator, and the contaminants contained in the cleaning liquid are attached to the electrode of the crystal oscillator; and a determination unit that determines the cleanliness of the cleaning member based on the measured vibration frequency response.

[0030] The computer-readable storage medium according to the thirteenth aspect of the embodiment stores the following control program non-transitorily: The program is a program for determining the cleanliness of a cleaning member that performs scrub cleaning in contact with a substrate, and causes the computer to A step of releasing contaminants from a cleaning member into a cleaning liquid, bringing the cleaning liquid containing the contaminants into contact with the electrodes of a crystal oscillator, attaching the contaminants contained in the cleaning liquid to the electrodes of the crystal oscillator, and then measuring the frequency response of the crystal oscillator with the contaminants attached to the electrodes; Based on the measured frequency response, a step of determining the cleanliness of the cleaning member is executed.

[0031] The substrate cleaning apparatus according to the 14th aspect of the embodiment is A cleaning member disposed in the housing and scrubbing the substrate in contact therewith; A self-cleaning device disposed in the housing for releasing contaminants from the cleaning member into the cleaning liquid; A crystal oscillator disposed in the housing; After the drainage of the self-cleaning device is brought into contact with the electrodes of the crystal oscillator and the contaminants contained in the drainage are attached to the electrodes of the crystal oscillator, the frequency response of the crystal oscillator with the contaminants attached to the electrodes is measured, and based on the measured frequency response, a determination device for determining the cleanliness of the cleaning member is provided.

[0032] The method according to the 15th aspect of the embodiment is A method for determining the adsorption characteristics of contaminants that contaminate a cleaning member that scrub-cleans in contact with a substrate, A step of immersing the cleaning member in pure water and releasing contaminants from the cleaning member into the pure water; Immersing a first crystal oscillator having a first substance with a first zeta potential formed on an electrode and a second crystal oscillator having a second substance with a second zeta potential different from the first zeta potential formed on an electrode in pure water containing contaminants, measuring the frequency responses of the first crystal oscillator and the second crystal oscillator, and determining the adsorption characteristics of the contaminants based on the difference in the time change of the frequency responses.

[0033] The method according to the 16th aspect of the embodiment is A method for determining the cleanliness of a substrate that scrub-cleans by bringing a cleaning member into contact with the substrate, A step of washing the substrate by bringing a cleaning member into contact with the substrate while supplying a chemical solution, and then washing the substrate with water; A step of sampling a part of the drainage water used for washing the substrate with water at a first timing, supplying the sampled drainage water onto the electrodes of a crystal oscillator, and then drying it to measure the frequency response of the crystal oscillator as a first frequency measurement value; A step of sampling a part of the drainage water used for washing the substrate with water at a second timing different from the first timing, supplying the sampled drainage water onto the electrodes of a crystal oscillator, and then drying it to measure the frequency response of the crystal oscillator as a second frequency measurement value; A step of determining the cleanliness of the drainage water based on the first frequency measurement value and the second frequency measurement value; A step of determining the cleanliness of the substrate based on the cleanliness of the drainage water, and includes.

[0034] The method according to the seventeenth aspect of the embodiment is the method according to the sixteenth aspect, The measurement of the frequency of the crystal oscillator is performed by sampling a part of the drainage water used for washing the substrate with water from a branch pipe branched from a drainage pipe, supplying the sampled drainage liquid onto the electrodes of the crystal oscillator, and then drying it.

[0035] The apparatus according to the eighteenth aspect of the embodiment is An apparatus for determining the cleanliness of a substrate that is scrubbed by bringing a cleaning member into contact with the substrate, After cleaning the substrate by bringing the cleaning member into contact with the substrate while supplying a chemical solution, when the substrate is washed with water, a part of the drainage used for washing the substrate at a first timing is sampled, and after the sampled drainage is supplied onto the electrode of the crystal oscillator and dried, the vibration frequency response of the crystal oscillator on which contaminants contained in the drainage are deposited on the electrode is measured as a first vibration frequency measurement value. Also, a part of the drainage used for washing the substrate at a second timing different from the first timing is sampled, and after the sampled drainage is supplied onto the electrode of the crystal oscillator and dried, the vibration frequency response of the crystal oscillator on which contaminants contained in the drainage are deposited on the electrode is measured as a second vibration frequency measurement value. Means for determining the cleanliness of the drainage based on the first vibration frequency measurement value and the second vibration frequency measurement value. Means for determining the cleanliness of the substrate based on the cleanliness of the drainage.

[0036] The computer-readable storage medium according to the 19th aspect of the embodiment stores the following control program non-temporarily: The program Is a program for determining the cleanliness of a substrate when scrubbing and cleaning the substrate by bringing a cleaning member into contact with the substrate using a substrate cleaning device. To the computer, After cleaning the substrate by bringing the cleaning member into contact with the substrate while supplying a chemical solution, when the substrate is washed with water, a part of the drainage used for washing the substrate at a first timing is sampled, and after the sampled drainage is supplied onto the electrode of the crystal oscillator and dried, the vibration frequency response of the crystal oscillator on which contaminants contained in the drainage are deposited on the electrode is measured as a first vibration frequency measurement value. A step of sampling a part of the drainage used for washing the substrate at a second timing different from the first timing, and after the sampled drainage is supplied onto the electrode of the crystal oscillator and dried, measuring the vibration frequency response of the crystal oscillator on which contaminants contained in the drainage are deposited on the electrode as a second vibration frequency measurement value. A step of determining the cleanliness of the drainage based on the first vibration frequency measurement value and the second vibration frequency measurement value. Execute a step of determining the cleanliness of the substrate based on the cleanliness of the drainage water.

[0037] A computer-readable storage medium according to the 20th aspect of the embodiment stores the following control program non-temporarily: The program is a program for determining the end point of a cleaning process of a substrate cleaning apparatus that continuously cleans a plurality of substrates, for a computer, After supplying a chemical solution and bringing a cleaning member into contact with a first substrate to clean the first substrate, when the first substrate is washed with water, a part of the drainage water used for washing the first substrate is sampled, and after the sampled drainage water is supplied onto the electrode of a crystal oscillator and dried, the vibration frequency response of the crystal oscillator on which contaminants contained in the drainage water are deposited on the electrode is measured as a first vibration frequency measurement value, and the number of defects on the first substrate evaluated by a defect inspection apparatus after the washed first substrate is dried is acquired from the defect inspection apparatus. When the number of defects is less than a predetermined reference value, recording the first vibration frequency measurement value as the end point of the cleaning process on a recording medium; After supplying a chemical solution and bringing a cleaning member into contact with a second substrate to clean the second substrate, when the second substrate is washed with water, a part of the drainage water used for washing the second substrate is sampled, and after the sampled drainage water is supplied onto the electrode of a crystal oscillator and dried, measuring the vibration frequency response of the crystal oscillator on which contaminants contained in the drainage water are deposited on the electrode as a second vibration frequency measurement value; Comparing the recorded first vibration frequency measurement value with the measured second vibration frequency measurement value, and when the second vibration frequency measurement value is greater than or equal to the first vibration frequency measurement value, determining that the end point of the cleaning process has been reached, and when the second vibration frequency measurement value is less than the first vibration frequency measurement value, determining that the end point of the cleaning process has not been reached; If it is determined that the end point has been reached, a first control signal for stopping the cleaning process of the second substrate is sent to the substrate cleaning apparatus, and if it is determined that the end point has not been reached, a second control signal for continuing the cleaning process of the second substrate is sent to the substrate cleaning apparatus.

[0038] The method according to the twenty-first aspect of the embodiment comprises: A method for determining the cleanliness of a cleaning member that contacts and scrubs a substrate, comprising: measuring the frequency of the quartz crystal oscillator before depositing the contaminant on the electrode and recording the frequency as an initial value in a recording medium; A step of immersing a cleaning member in pure water and releasing contaminants from the cleaning member into the pure water; A step of starting stirring the pure water containing the contaminants and then sampling the pure water as a sample liquid; A step of dropping a predetermined amount of the sample liquid onto the electrodes of the quartz crystal oscillator and drying the sample liquid to cause contaminants contained in the sample liquid to precipitate on the electrodes of the quartz crystal oscillator; A step of measuring the frequency of the quartz crystal resonator on which the contaminant has been deposited on the electrode, receiving a signal relating to the measured frequency in a control unit, calculating a difference between the measured value and the initial value while referring to the initial value in the control unit, and measuring the amount of the contaminant deposited on the electrode based on the calculated difference; and determining the cleanliness of the cleaning member based on the amount of contaminants deposited on the electrode.

[0039] According to this embodiment, since the amount of contaminants is measured based on measuring the frequency of the quartz oscillator, it is possible to detect even very small amounts of contaminants. By determining the cleanliness of the cleaning member based on the measurement results, it becomes less likely that a cleaning member containing remaining contaminants will be erroneously determined to be "clean." In other words, it becomes possible to accurately determine the cleanliness of the cleaning member.

[0040] A method according to a twenty-second aspect of the embodiment is the method according to the twenty-first aspect, A step of immersing a crystal oscillator with contaminants deposited on an electrode in a liquid, measuring the time change of the oscillation frequency of the crystal oscillator, and measuring the mass of the liquid-soluble contaminants based on the difference between the oscillation frequency when the time change reaches saturation and the oscillation frequency immediately after immersion in the liquid further comprises.

[0041] According to such an aspect, it is possible to determine whether the contaminants of the cleaning member contain a liquid-soluble substance, and it is possible to classify and measure the chemical characteristics (liquid solubility) of the contaminants.

[0042] The method according to the 23rd aspect of the embodiment is the method according to the 22nd aspect, a step of calculating the mass of the liquid-insoluble contaminants based on the difference between the mass of the contaminants deposited on the electrode and the mass of the liquid-soluble contaminants further comprises.

[0043] According to such an aspect, it is possible to determine whether the contaminants of the cleaning member contain a liquid-insoluble substance, and it is possible to classify and measure the chemical characteristics (liquid insolubility) of the contaminants.

[0044] The method according to the 24th aspect of the embodiment is the method according to the 22nd or 23rd aspect, wherein the liquid is pure water.

[0045] According to such an aspect, it becomes possible to determine whether the contaminants of the cleaning member contain a water-soluble substance (or a water-insoluble substance).

[0046] The method according to the 25th aspect of the embodiment is a method for determining the adsorption characteristics of contaminants that contaminate a cleaning member that performs scrub cleaning in contact with a substrate, immersing the cleaning member in pure water and releasing the contaminants from the cleaning member into the pure water, A first crystal oscillator having a first substance with a first zeta potential formed on an electrode and a second crystal oscillator having a second substance with a second zeta potential different from the first zeta potential formed on an electrode are immersed in pure water containing a pollutant, the oscillation frequencies of the first crystal oscillator and the second crystal oscillator are measured, and based on the difference in the time change of the oscillation frequencies, a step of determining the adsorption characteristics of the pollutant; including.

[0047] According to such an aspect, in order to determine the adsorption characteristics of the pollutant based on the measurement of the oscillation frequencies of the first crystal oscillator and the second crystal oscillator, it is possible to determine the adsorption characteristics even for a very small amount of pollutant, that is, it is possible to quantitatively evaluate the adsorption characteristics of the pollutant that contaminates the cleaning member.

[0048] The apparatus according to the 26th aspect of the embodiment is an apparatus for determining the cleanliness of a cleaning member that scrub-cleans in contact with a substrate, means for measuring the oscillation frequency of the crystal oscillator before depositing the pollutant on the electrode and recording it on a recording medium as an initial value; After the cleaning member is immersed in pure water, the pollutant is released from the cleaning member into the pure water, and after the stirring of the pure water containing the pollutant is started, it is sampled as a sample solution, and a predetermined amount of the sample solution sampled on the electrode of the crystal oscillator is dropped and dried, so that the oscillation frequency of the crystal oscillator on which the pollutant contained in the sample solution is deposited is measured, the difference between the measured value and the initial value is calculated while referring to the initial value, and based on the calculated difference, means for measuring the amount of the pollutant deposited on the electrode; means for determining the cleanliness of the cleaning member based on the amount of the pollutant deposited on the electrode; comprising.

[0049] The computer-readable storage medium according to the 27th aspect of the embodiment stores the following control program non-temporarily: The program is a program for determining the cleanliness of a cleaning member that scrub-cleans in contact with a substrate, to the computer, Measuring the vibration frequency of the crystal oscillator before depositing contaminants on the electrode and recording it on a recording medium as an initial value; After the cleaning member is immersed in pure water, contaminants are released from the cleaning member into the pure water, and after stirring of the pure water containing the contaminants is started, it is sampled as a sample solution, and a predetermined amount of the sampled sample solution is dropped onto the electrode of the crystal oscillator and dried, thereby measuring the vibration frequency of the crystal oscillator on which the contaminants contained in the sample solution are deposited on the electrode, calculating the difference between the measured value and the initial value while referring to the initial value, and measuring the amount of contaminants deposited on the electrode based on the calculated difference; Determining the cleanliness of the cleaning member based on the amount of contaminants deposited on the electrode.

[0050] The method according to the 28th aspect of the embodiment is A method for determining the cleanliness of a substrate by scrub cleaning with a cleaning member in contact with the substrate, After cleaning the substrate by bringing the cleaning member into contact with the substrate while supplying a chemical solution, washing the substrate with water; Sampling a part of the drainage water used for washing the substrate at a first timing, supplying the sampled drainage water onto the electrode of the crystal oscillator, and drying it to measure the vibration frequency of the crystal oscillator as a first vibration frequency measurement value; Sampling a part of the drainage water used for washing the substrate at a second timing different from the first timing, supplying the sampled drainage water onto the electrode of the crystal oscillator, and drying it to measure the vibration frequency of the crystal oscillator as a second vibration frequency measurement value; Determining the cleanliness of the drainage water based on the first vibration frequency measurement value and the second vibration measurement value; Determining the cleanliness of the substrate based on the cleanliness of the drainage water. Including.

[0051] According to such an aspect, since the amount of contaminants is measured based on the measurement of the oscillation frequency of the crystal oscillator, it is possible to detect even very trace amounts of contaminants. Based on the measurement result, the cleanliness of the wastewater is determined, and based on the determination result, the cleanliness of the substrate is determined. As a result, it is less likely to misjudge a substrate with remaining contaminants as "clean", that is, it becomes possible to accurately determine the cleanliness of the substrate.

[0052] The method according to the 29th aspect of the embodiment is the method according to the 8th aspect, and the measurement of the oscillation frequency of the crystal oscillator is performed by sampling a part of the wastewater used for washing the substrate from a branch pipe branched from the wastewater pipe, supplying the sampled drained liquid onto the electrodes of the crystal oscillator, and then drying it to measure the oscillation frequency of the crystal oscillator.

[0053] The apparatus according to the 30th aspect of the embodiment is an apparatus for determining the cleanliness of a substrate by scrubbing and cleaning by bringing a cleaning member into contact with the substrate, after supplying a chemical solution and bringing the cleaning member into contact with the substrate to clean the substrate, when the substrate is washed with water, a part of the wastewater used for washing the substrate is sampled at a first timing, and after the sampled wastewater is supplied onto the electrodes of the crystal oscillator and dried, the oscillation frequency of the crystal oscillator on which contaminants contained in the wastewater are deposited on the electrodes is measured as a first oscillation frequency measurement value. Also, a part of the wastewater used for washing the substrate is sampled at a second timing different from the first timing, and after the sampled wastewater is supplied onto the electrodes of the crystal oscillator and dried, the oscillation frequency of the crystal oscillator on which contaminants contained in the wastewater are deposited on the electrodes is measured as a second oscillation frequency measurement value; means for determining the cleanliness of the wastewater based on the first oscillation frequency measurement value and the second oscillation frequency measurement value; means for determining the cleanliness of the substrate based on the cleanliness of the wastewater; and is provided with.

[0054] A computer-readable storage medium according to the 31st aspect of the embodiment non-temporarily stores the following control program: The program is A program for determining the cleanliness of a substrate when scrubbing and cleaning a cleaning member against the substrate using a substrate cleaning device, to cause a computer After supplying a chemical solution and bringing a cleaning member into contact with the substrate to clean the substrate, when the substrate is washed with water, a part of the drainage water used for washing the substrate at a first timing is sampled, and after the sampled drainage water is supplied onto the electrodes of a crystal oscillator and dried, the frequency of the crystal oscillator on which contaminants contained in the drainage water are deposited on the electrodes is measured as a first frequency measurement value; A part of the drainage water used for washing the substrate at a second timing different from the first timing is sampled, and after the sampled drainage water is supplied onto the electrodes of a crystal oscillator and dried, the frequency of the crystal oscillator on which contaminants contained in the drainage water are deposited on the electrodes is measured as a second frequency measurement value; Based on the first frequency measurement value and the second frequency measurement value, determining the cleanliness of the drainage water; Based on the cleanliness of the drainage water, determining the cleanliness of the substrate; to execute.

[0055] A computer-readable storage medium according to the 32nd aspect of the embodiment non-temporarily stores the following control program: The program is A program for determining the end point of the cleaning process of a substrate cleaning device that continuously cleans a plurality of substrates, to cause a computer After cleaning the first substrate by bringing a cleaning member into contact with the first substrate while supplying a chemical solution, when the first substrate is washed with water, a part of the wastewater used for washing the first substrate is sampled. After the sampled wastewater is supplied onto the electrodes of the crystal oscillator and dried, the frequency of the crystal oscillator on which contaminants contained in the wastewater are deposited on the electrodes is measured as a first frequency measurement value. At the same time, the number of defects on the first substrate that has been washed with water and dried and evaluated by a defect inspection device is obtained from the defect inspection device. When the number of defects is less than a predetermined reference value, a step of recording the first frequency measurement value as the end point of the cleaning process on a recording medium; After cleaning the second substrate by bringing a cleaning member into contact with the second substrate while supplying a chemical solution, when the second substrate is washed with water, a part of the wastewater used for washing the second substrate is sampled. After the sampled wastewater is supplied onto the electrodes of the crystal oscillator and dried, a step of measuring the frequency of the crystal oscillator on which contaminants contained in the wastewater are deposited on the electrodes as a second frequency measurement value; A step of comparing the recorded first frequency measurement value with the measured second frequency measurement value, and determining that the end point of the cleaning process has been reached when the second frequency measurement value is greater than or equal to the first frequency measurement value, and determining that the end point of the cleaning process has not been reached when the second frequency measurement value is less than the first frequency measurement value; When it is determined that the end point has been reached, a first control signal for stopping the cleaning process and starting the drying process of the second substrate is transmitted to the substrate cleaning device. When it is determined that the end point has not been reached, a second control signal for continuing the cleaning process of the second substrate is transmitted to the substrate cleaning device; To execute.

[0056] Hereinafter, specific examples of embodiments will be described in detail with reference to the accompanying drawings. In the following description and the drawings used in the following description, the same reference numerals are used for parts that can be configured identically, and duplicate descriptions are omitted.

[0057] (First Embodiment) FIG. 1 is a block diagram showing the configuration of the determination device 10 according to the first embodiment. The determination device 10 according to the first embodiment is a device that determines the cleanliness of a cleaning member that comes into contact with a substrate and performs scrub cleaning. The determination device 10 is configured by one or more computers.

[0058] As shown in FIG. 1, the determination device 10 includes an input unit 11, a control unit 12, a storage unit 13, and an output unit 14. Each unit is communicably connected to each other via a bus.

[0059] Among these, the input unit 11 is a communication interface between the QCM (Quartz Crystal Microbalance) sensor 50 and the determination device 10. The input unit 11 receives data on the vibration frequency of the crystal oscillator output from the QCM sensor 50.

[0060] The output unit 14 is an interface that outputs various information from the determination device 10 to the user, and is, for example, a video display means such as a liquid crystal display or an audio output means such as a speaker. The determination result by the cleanliness determination unit 12c described later is output to the user via the output unit 14.

[0061] The storage unit 13 is a non-volatile data storage such as a flash memory, for example. Various data handled by the control unit 12 are stored in the storage unit 13. Further, an initial value 13a of the vibration frequency of the crystal oscillator measured by the initial value measurement unit 12a described later is recorded in the storage unit 13.

[0062] The control unit 12 is control means for performing various processes of the determination device 10. As shown in FIG. 1, the control unit 12 includes an initial value measurement unit 12a, a contaminant amount measurement unit 12b, and a cleanliness determination unit 12c. Each of these units may be realized by a processor in the determination device 10 executing a predetermined program, or may be implemented in hardware.

[0063] The initial value measurement unit 12a measures the vibration frequency of the crystal oscillator of the QCM sensor 50 before depositing contaminants on the electrode, and records it in the storage unit 13 (recording medium) as the initial value 13a.

[0064] The contaminant amount measurement unit 12b samples the sample liquid after the cleaning member is immersed in pure water, contaminants are released from the cleaning member into the pure water, and stirring of the pure water containing the contaminants is started. After a predetermined amount of the sampled sample liquid is dropped onto the electrode of the crystal oscillator of the QCM sensor 50 and dried, the contaminant amount measurement unit 12b measures the vibration frequency of the crystal oscillator on which the contaminants contained in the sample liquid are deposited on the electrode. Then, while referring to the initial value 13a, the contaminant amount measurement unit 12b calculates the difference between the measured value and the initial value 13a, and measures the amount of contaminants deposited on the electrode based on the calculated difference.

[0065] The cleanliness determination unit 12c determines the cleanliness of the cleaning member based on the amount of contaminants deposited on the electrode measured by the contaminant amount measurement unit 12b. For example, the cleanliness determination unit 12c compares the amount of contaminants deposited on the electrode with a predetermined threshold value. If the amount of contaminants deposited on the electrode is equal to or less than the threshold value, it is determined that the cleaning member is "clean", and if it is greater than the threshold value, it is determined that the cleaning member is "contaminated" (contaminants remain on the cleaning member).

[0066] The contaminant amount measurement unit 12b may measure the mass of the liquid-soluble contaminants based on the difference between the vibration frequency when the time change of the vibration frequency of the crystal oscillator of the QCM sensor 50 on which contaminants are deposited is saturated and the vibration frequency immediately after being immersed in the liquid (for example, pure water) with the crystal oscillator immersed in the liquid.

[0067] The contaminant amount measurement unit 12b may calculate the mass of the liquid-insoluble contaminants based on the difference between the mass of the contaminants deposited on the electrode and the mass of the liquid-soluble contaminants.

[0068] Next, a determination method according to the first embodiment will be described. FIGS. 2A and 2B are flowcharts showing the determination method according to the first embodiment.

[0069] As shown in FIG. 2A, first, the initial value measurement unit 12a measures the vibration frequency of the crystal oscillator of the QCM sensor 50 before depositing contaminants on the electrode, and records it as the initial value 13a in the storage unit 13 (recording medium) (step S11).

[0070] Next, the user immerses the cleaning member in pure water and releases contaminants from the cleaning member into the pure water (step S13). At this time, ultrasonic waves may be applied to the pure water to vibrate it, or the cleaning member may be kneaded and washed.

[0071] Next, after the user starts stirring the pure water containing contaminants, the user samples it as a sample solution using a pipette or the like in a uniform state (step S13).

[0072] Next, the user drops a predetermined amount (for example, several microliters) of the sampled sample solution onto the electrode of the crystal oscillator of the QCM sensor 50 and dries it, thereby depositing the contaminants contained in the sample solution on the electrode of the crystal oscillator (step S14).

[0073] Next, the contaminant amount measurement unit 12b measures the vibration frequency of the crystal oscillator of the QCM sensor 50 on which contaminants are deposited, receives a signal regarding the measured vibration frequency, calculates the difference between the measured value and the initial value 13a while referring to the initial value 13a, and measures the amount of contaminants deposited on the electrode based on the calculated difference (step S15).

[0074] More specifically, in the QCM sensor 50, electrodes are provided on both the front and back surfaces of the crystal oscillator, and the crystal oscillator vibrates by applying a voltage to the electrodes. The vibration frequency of this crystal oscillator changes depending on the mass of the electrodes. In the case of this embodiment, after contaminants are deposited on the electrodes, the vibration frequency of the crystal oscillator decreases. If the initial value 13a is A0 and the measured value in the state where contaminants are deposited on the electrodes is A1, the absolute value of the numerical value (A0 - A1) obtained by multiplying the difference A0 - A1 between the measured value A1 and the initial value A0 by the mass / vibration frequency ratio B specific to this crystal oscillator is the mass of the contaminants (contaminant amount).

[0075] Next, the cleanliness determination unit 12c determines the cleanliness of the cleaning member based on the amount of contaminants deposited on the electrodes (step S16). For example, the cleanliness determination unit 12c compares the amount of contaminants deposited on the electrodes with a predetermined threshold value. If the amount of contaminants deposited on the electrodes is equal to or less than the threshold value, it determines that the cleaning member is "clean", and if it is greater than the threshold value, it determines that it is "contaminated" (contaminants remain on the cleaning member). The determination result by the cleanliness determination unit 12c is output to the user via the output unit 14.

[0076] Next, the user immerses the crystal oscillator of the QCM sensor 50 on which contaminants are deposited in a liquid (for example, pure water) (step S17).

[0077] Then, the contaminant amount measurement unit 12b measures the time change in the vibration frequency of the crystal oscillator immersed in the liquid, and measures the mass of the liquid-soluble contaminants based on the difference between the vibration frequency when the time change has saturated and the vibration frequency immediately after immersion in the liquid (step S18).

[0078] Also, the contaminant amount measurement unit 12b calculates the mass of the liquid-insoluble contaminants based on the difference between the mass of the contaminants deposited on the electrodes and the mass of the liquid-soluble contaminants (step S19).

[0079] Next, an example of the first embodiment will be described with reference to Fig. 3. Fig. 3 is a graph showing the time change in the frequency of a quartz crystal resonator immersed in a liquid. In this example, pure water was used as the liquid, and quantitative measurements were made to determine whether or not contaminants released from a polyvinyl formal brush, which is often used as a cleaning member, were water-soluble.

[0080] In the graph of Figure 3, C1 indicates the vibration frequency measured when the initial quartz crystal unit, before any contaminants were deposited on the electrodes, was immersed in liquid. C2 indicates the vibration frequency immediately after the quartz crystal unit with contaminants deposited on the electrodes was immersed in pure water. (C1-C2) x B is the mass of the contaminants.

[0081] As shown in Figure 3, the vibration frequency of the quartz crystal unit with the contaminants deposited on the electrode gradually increased over time immediately after the quartz crystal unit was immersed in pure water, and gradually saturated. C3 shows this saturated vibration frequency.

[0082] This change in frequency represents the phenomenon of the contaminant dissolving in pure water. In other words, it indicates that the contaminant contains a water-soluble component, whose mass is (C2-C3)×B.

[0083] In this embodiment, a polyvinyl formal brush was used as the cleaning member, and since its raw material, polyvinyl alcohol, is water-soluble, it can be assumed that polyvinyl alcohol is included in the contaminants of the cleaning member as a water-soluble contaminant.

[0084] On the other hand, from the graph in Figure 3, it can be seen that the mass of the water-insoluble contaminants was (C1-C3) x B. This shows that the contaminants adhering to the cleaning member were not of one type, but were composed of different substances, and that water-soluble substances were also included among them.

[0085] In addition, in this embodiment, pure water is used as the liquid. However, the present invention is not limited to this, and by using other solvents as the liquid, it is possible to more finely classify the chemical properties of the contaminants on the cleaning member.

[0086] According to the above-described embodiment, since the amount of contaminants is measured based on the measurement of the vibration frequency of the crystal oscillator, it is possible to detect even very minute amounts of contaminants. By determining the cleanliness of the cleaning member based on the measurement result, it is less likely to misjudge a cleaning member with remaining contaminants as "clean", that is, it becomes possible to accurately determine the cleanliness of the cleaning member.

[0087] Also, according to this embodiment, a crystal oscillator with contaminants deposited on the electrodes is immersed in a liquid, and the mass of the liquid-soluble contaminants is measured based on the time change of the vibration frequency of the crystal oscillator. Thus, it can be determined whether the contaminants on the cleaning member contain liquid-soluble substances, and classification measurement of the chemical properties (liquid solubility) of the contaminants becomes possible.

[0088] Also, according to this embodiment, the mass of the liquid-insoluble contaminants is calculated based on the difference between the mass of the contaminants deposited on the electrodes and the mass of the liquid-soluble contaminants. Thus, it can be determined whether the contaminants on the cleaning member contain liquid-insoluble substances, and classification measurement of the chemical properties (liquid insolubility) of the contaminants becomes possible.

[0089] (Second Embodiment) Next, the second embodiment will be described. The determination method according to the second embodiment is a method for determining the adsorption characteristics of contaminants that contaminate a cleaning member that scrub-cleans in contact with a substrate.

[0090] When the substrate to which the cleaning member is to be brought into contact has a high adsorbability of contaminants, it is conceivable that the contaminants released from the cleaning member may reverse-contaminate the substrate. Therefore, it is important to grasp the adsorption characteristics of contaminants with respect to the substrate. As a parameter indicating this adsorption characteristic, a measured value called zeta potential is often used. It is judged that substances with the same sign of zeta potential are less likely to adsorb, while substances with opposite signs of zeta potential are more likely to adsorb. This characteristic of zeta potential generally has pH dependence, and data on the pH dependence of the zeta potential of various substances are publicly available.

[0091] Therefore, in the present embodiment, a thin film of a substance with known zeta potential is prepared by forming it on the Au electrode of the crystal oscillator of the QCM sensor. It is desirable to prepare two or more crystal oscillators with different substances having different zeta potentials formed on the electrodes respectively. Furthermore, it is more desirable to prepare a crystal oscillator with the same substance as the substrate to be cleaned formed on the electrode of the crystal oscillator. By forming a thin film of another substance on the Au electrode of the crystal oscillator, it is possible to determine the adsorption characteristics of contaminants as described below.

[0092] FIG. 4 is a flowchart showing a determination method according to the second embodiment.

[0093] In the determination method according to the second embodiment, first, as shown in FIG. 5, the cleaning member 31 is immersed in pure water 20 to release contaminants from the cleaning member 31 into the pure water (step S21). At this time, ultrasonic waves may be applied to the pure water 20 to vibrate it, or the cleaning member 31 may be rubbed and washed.

[0094] Next, as shown in FIG. 5, in the pure water 20 containing contaminants, the first crystal oscillator 21 with the first substance having the first zeta potential formed on the electrode and the second crystal oscillator 22 with the second substance having the second zeta potential different from the first zeta potential formed on the electrode are immersed (step S22). Although not shown, a third crystal oscillator with the same substance as the substrate to be cleaned formed on the electrode may be further immersed in the pure water 20.

[0095] Contaminants contained in the pure water 20 approach the vicinity of the electrodes of the quartz crystal oscillators 21, 22 immersed in the pure water 20. At this time, if the contaminants and the substances formed on the electrodes of the quartz crystal oscillators 21, 22 have zeta potentials of opposite signs, a strong electrostatic attraction acts between them, the contaminants are adsorbed onto the electrodes, and the vibration frequency of the quartz crystal oscillators 21, 22 changes. On the other hand, if the contaminants and the substances formed on the electrodes of the quartz crystal oscillators 21, 22 have the same zeta potential characteristics, an electrostatic repulsion acts conversely, the contaminants are not adsorbed onto the electrodes, and the vibration frequency of the quartz crystal oscillators 21, 22 does not change.

[0096] Therefore, the vibration frequencies of the first and second quartz crystal oscillators 21 and 22 are measured, and the adsorption characteristics of the contaminants are determined based on the difference in the time change of the vibration frequencies (step S23). This makes it possible to qualitatively estimate not only the adsorption characteristics and adsorption amount of the contaminants released from the cleaning member onto the substrate to be cleaned, but also the zeta potential characteristics of the contaminants.

[0097] According to the present embodiment as described above, the adsorption characteristics of the contaminant are determined based on measuring the vibration frequencies of the first quartz crystal oscillator 21 and the second quartz crystal oscillator 22, so that it is possible to determine the adsorption characteristics even of very small amounts of contaminant. In other words, it is possible to quantitatively evaluate the adsorption characteristics of the contaminant that contaminates the cleaning member.

[0098] (Third embodiment) Next, a third embodiment will be described. Fig. 6 is a block diagram showing the configuration of a determination device 100 according to the third embodiment. The determination device 100 according to the third embodiment is an apparatus for determining the cleanliness of a substrate W that is scrubbed by bringing a cleaning member 31 into contact with the substrate W, as shown in Figs. 8 and 9.

[0099] 6, the determination device 100 includes an input unit 111, a control unit 112, a storage unit 113, and an output unit 114. Each unit is connected to each other via a bus so as to be able to communicate with each other.

[0100] Among these, the input unit 111 is a communication interface between the QCM (Quartz Crystal Microbalance) sensor 50 and the determination device 100. The input unit 111 receives the data of the oscillation frequency of the crystal oscillator output from the QCM sensor 50.

[0101] The output unit 114 is an interface that outputs various information to the user from the determination device 100, and is, for example, video display means such as a liquid crystal display or audio output means such as a speaker. The determination result by the substrate cleanliness determination unit 112c described later is output to the user via the output unit 114.

[0102] The storage unit 113 is a non-volatile data storage such as a flash memory, for example. Various data handled by the control unit 112 are stored in the storage unit 113. Further, a measurement value 113a of the oscillation frequency of the crystal oscillator measured by the oscillation frequency measurement unit 112a described later is recorded in the storage unit 113.

[0103] The control unit 112 is control means for performing various processes of the determination device 100. As shown in FIG. 6, the control unit 112 includes an oscillation frequency measurement unit 112a, a drainage cleanliness determination unit 112b, and a substrate cleanliness determination unit 112c. Each of these units may be realized by a processor in the determination device 100 executing a predetermined program, or may be implemented in hardware.

[0104] While supplying the chemical solution, the vibration frequency measurement unit 112a brings the cleaning member 31 into contact with the substrate W to clean the substrate. Then, when the substrate W is washed with water, a part of the drained water 40 used for washing the substrate W at the first timing is sampled. After the sampled drained water 40 is supplied onto the electrodes of the crystal oscillator of the QCM sensor 50 and then dried, the vibration frequency of the crystal oscillator on which contaminants contained in the drained water 40 are deposited on the electrodes is measured as the first vibration frequency measurement value. Further, the vibration frequency measurement unit 112a samples a part of the drained water 40 used for washing the substrate W at a second timing different from the first timing. After the sampled drained water 40 is supplied onto the electrodes of the crystal oscillator of the QCM sensor 50 and then dried, the vibration frequency of the crystal oscillator on which contaminants contained in the drained water are deposited on the electrodes is measured as the second vibration frequency measurement value. The first vibration frequency measurement value and the second vibration frequency measurement value are stored in the storage unit 113 as the vibration frequency measurement value 113a.

[0105] Based on the first vibration frequency measurement value and the second vibration frequency measurement value measured by the vibration frequency measurement unit 112a, the drained water cleanliness determination unit 112b determines the cleanliness of the drained water 40. For example, the drained water cleanliness determination unit 112b compares the first vibration frequency measurement value with the second vibration frequency measurement value. If the second vibration frequency measurement value is smaller than the first vibration frequency measurement value, it is determined that the drained water 40 is "clean". If the second vibration frequency measurement value is greater than or equal to the first vibration frequency measurement value, it is determined that the drained water is "contaminated" (contaminants remain in the drained water 40).

[0106] Based on the cleanliness of the drained water 40 determined by the drained water cleanliness determination unit 112b, the substrate cleanliness determination unit 113b determines the cleanliness of the substrate W. For example, when the drained water 40 is "clean", the substrate cleanliness determination unit 113b determines that the substrate W is also "clean". When the drained water 40 is "contaminated", the substrate cleanliness determination unit 113b determines that the substrate W is also "contaminated" (contaminants remain on the substrate).

[0107] Next, the determination method according to the third embodiment will be described. FIG. 7 is a flowchart showing the determination method according to the third embodiment.

[0108] As shown in FIGS. 7 and 8, first, while supplying a chemical solution onto the substrate W, the cleaning member 31 is brought into contact with the substrate W to clean the substrate W. Then, the cleaning member 31 is separated from the substrate W. Next, pure water is supplied onto the substrate W to wash away contaminants on the substrate W (water-wash the substrate W) (step S31).

[0109] Next, the user samples a part of the drainage 40 used for water-washing the substrate W at the first timing. Here, as shown in FIG. 8, a part of the drainage 40 may be sampled from the drainage pipe 41, or as shown in FIG. 9, it may be sampled from the branch pipe 42 branched from the drainage pipe 41. Then, after the user supplies the sampled drainage onto the electrode of the crystal oscillator and dries it, contaminants are deposited on the electrode. Then, the vibration frequency measurement unit 112a measures the vibration frequency of the crystal oscillator with contaminants deposited on the electrode as the first vibration frequency measurement value (step S32).

[0110] Next, the user samples a part of the drainage 40 used for water-washing the substrate W from the drainage pipe 41 or the branch pipe 42 at a second timing different from the first timing. After supplying the sampled drainage onto the electrode of the crystal oscillator and drying it, contaminants are deposited on the electrode. Then, the vibration frequency measurement unit 112a measures the vibration frequency of the crystal oscillator with contaminants deposited on the electrode as the second vibration frequency measurement value (step S33).

[0111] Next, the drainage cleanliness determination unit 112b determines the cleanliness of the drainage 40 based on the first vibration frequency measurement value and the second vibration frequency measurement value measured by the vibration frequency measurement unit 112a (step S34). For example, the drainage cleanliness determination unit 112b compares the first vibration frequency measurement value with the second vibration frequency measurement value. If the second vibration frequency measurement value is smaller than the first vibration frequency measurement value, it is determined that the drainage 40 is "clean", and if the second vibration frequency measurement value is equal to or greater than the first vibration frequency measurement value, it is determined that the drainage is "contaminated" (contaminants remain in the drainage 40).

[0112] Then, the substrate cleanliness determination unit 113b determines the cleanliness of the substrate W based on the cleanliness of the drained water 40 determined by the drained water cleanliness determination unit 112b (step S35). For example, when the drained water 40 is "clean", the substrate cleanliness determination unit 113b determines that the substrate W is also "clean", and when the drained water 40 is "contaminated", the substrate cleanliness determination unit 113b determines that the substrate W is also "contaminated" (contaminant substances remain on the substrate). The determination result by the substrate cleanliness determination unit 113b is output to the user via the output unit 114.

[0113] According to the present embodiment as described above, since the amount of contaminant substances is measured based on the measurement of the vibration frequency of the crystal oscillator, it is possible to detect even very minute contaminant substances. Based on the measurement result, the cleanliness of the drained water 40 is determined, and based on the determination result, the cleanliness of the substrate W is determined. As a result, it becomes less likely to erroneously determine a substrate W with remaining contaminant substances as "clean", that is, it becomes possible to accurately determine the cleanliness of the substrate W.

[0114] (Fourth Embodiment) Next, the fourth embodiment will be described. FIG. 10 is a block diagram showing the configuration of a determination device 200 according to the fourth embodiment. The determination device 200 according to the fourth embodiment is a device that determines the end point of a cleaning process in a substrate cleaning device 70 that continuously cleans a plurality of substrates W.

[0115] As shown in FIG. 10, the determination device 200 includes an input unit 211, a control unit 212, a storage unit 213, and an output unit 214. Each unit is connected to communicate with each other via a bus.

[0116] Among these, the input unit 211 is a communication interface between the QCM (Quartz Crystal Microbalance) sensor 50 and the determination device 200. The input unit 211 receives data on the vibration frequency of the crystal oscillator output from the QCM sensor 50.

[0117] The output unit 214 is a communication interface between the control unit of the substrate cleaning apparatus 70 and the determination apparatus 200. The control signal generated by the control signal transmission unit 212d described later is output to the control unit of the substrate cleaning apparatus 70 via the output unit 214.

[0118] The storage unit 213 is a non-volatile data storage such as a flash memory, etc. Various data handled by the control unit 212 are stored in the storage unit 213. Further, the storage unit 213 stores the first vibration frequency measurement value 213a evaluated as the end point of the cleaning process by the cleaning process end point recording unit 212a described later.

[0119] The control unit 212 is a control means for performing various processes of the determination apparatus 200. As shown in FIG. 10, the control unit 212 includes a cleaning process end point recording unit 212a, a vibration frequency measurement unit 212b, an end point determination unit 212c, and a control signal transmission unit 212d. Each of these units may be realized by a processor in the determination apparatus 200 executing a predetermined program, or may be implemented by hardware.

[0120] After the cleaning member is brought into contact with the first substrate W1 while supplying a chemical solution in the substrate cleaning apparatus 70 to clean the first substrate W1, and then the first substrate W1 is washed with water, a part of the drainage water used for washing the first substrate W1 with water is sampled. After the sampled drainage water is supplied onto the electrode of the crystal oscillator of the QCM sensor 50 and dried, the vibration frequency of the crystal oscillator on which contaminants contained in the drainage water are deposited on the electrode is measured as the first vibration frequency measurement value. Further, the cleaning process end point recording unit 212a acquires the number of defects on the first substrate W1 evaluated by the defect inspection apparatus 60 after the washed first substrate W1 is dried from the defect inspection apparatus 60. Then, when the number of defects acquired from the defect inspection apparatus 60 is less than a predetermined reference value, the cleaning process end point recording unit 212a records the first vibration frequency measurement value 213a in the recording unit 213 as the end point of the cleaning process.

[0121] While supplying a chemical solution in the substrate cleaning apparatus 70, the cleaning member is brought into contact with the second substrate W2 to clean the second substrate W2. After that, when the second substrate W2 is rinsed with water, a part of the drained water 40 used for rinsing the second substrate W2 is sampled. After the sampled drained water 40 is supplied onto the electrodes of the crystal oscillator of the QCM sensor 50 and then dried, the frequency of the crystal oscillator on which contaminants contained in the drained water are deposited on the electrodes is measured as a second frequency measurement value.

[0122] The end point determination unit 212c compares the first frequency measurement value 213a recorded in the recording unit 213 with the second frequency measurement value measured by the frequency measurement unit 212b. When the second frequency measurement value is equal to or greater than the first frequency measurement value, it is determined that the end point of the cleaning process has been reached. When the second frequency measurement value is less than the first frequency measurement value, it is determined that the end point of the cleaning process has not been reached.

[0123] When the end point determination unit 212c determines that the end point has been reached, the control signal transmission unit 212d transmits a first control signal for stopping the cleaning process and starting the drying process of the second substrate W2 to the control unit of the substrate cleaning apparatus 70 via the output unit 214. Further, when the end point determination unit 212c determines that the end point has not been reached, the control signal transmission unit 212d transmits a second control signal for continuing the cleaning process of the second substrate W2 to the control unit of the substrate cleaning apparatus 70 via the output unit 214.

[0124] Next, a determination method according to the fourth embodiment will be described. FIGS. 11A and 11B are flowcharts showing the determination method according to the fourth embodiment.

[0125] As shown in FIG. 11A, first, while supplying a chemical solution onto the first substrate W1 in the substrate cleaning apparatus 70, the cleaning member is brought into contact with the first substrate W1 to clean the first substrate W1. After that, the cleaning member is separated from the first substrate W1. Then, pure water is supplied onto the first substrate W1 to wash away the contaminants on the first substrate W1 (rinsing the first substrate W1 with water) (step S41).

[0126] Next, a part of the wastewater used for the water washing of the first substrate W1 is sampled by the user, and after the sampled wastewater is supplied onto the electrode of the crystal oscillator of the QCM sensor 50 and then dried, contaminants are deposited on the electrode. Then, the cleaning process end recording unit 212a measures the vibration frequency of the crystal oscillator on which contaminants are deposited as the first vibration frequency measurement value (step S42).

[0127] Next, after the washed first substrate W1 is dried, the number of defects on the first substrate W1 is evaluated by the defect inspection device 60 (step S43). Then, the cleaning process end recording unit 212a acquires the number of defects on the first substrate W1 from the defect inspection device 60, compares the acquired number of defects with a predetermined reference value, and when the acquired number of defects is less than the predetermined reference value, records the first vibration frequency measurement value 213a measured in step S42 as the end point of the cleaning process in the recording unit 213 (step S44).

[0128] Next, as shown in FIG. 12B, in the substrate cleaning device 70, while supplying a chemical solution onto a second substrate W2 different from the first substrate W1, the cleaning member is brought into contact with the second substrate W2 to clean the second substrate W2, then the cleaning member is separated from the second substrate W2, and then pure water is supplied onto the second substrate W2 to wash away the contaminants on the second substrate W2 (water wash the second substrate W2) (step S51).

[0129] Next, a part of the wastewater used for the water washing of the second substrate W2 is sampled by the user, and after the sampled wastewater is supplied onto the electrode of the crystal oscillator of the QCM sensor 50 and then dried, contaminants are deposited on the electrode. Then, the vibration frequency measurement unit 212b measures the vibration frequency of the crystal oscillator on which contaminants are deposited as the second vibration frequency measurement value (step S52).

[0130] Next, the end point determination unit 212c compares the first vibration frequency measurement value 213a recorded in the recording unit 213 in step S44 with the second vibration frequency measurement value measured by the vibration frequency measurement unit 212b in step S52 (step 53).

[0131] When the second vibration frequency measurement value is equal to or greater than the first vibration frequency measurement value 213a (step S54: YES), the end point determination unit 212c determines that the end point of the cleaning process has been reached (step S55). Then, the control signal transmission unit 212d transmits a first control signal for stopping the cleaning process and starting the drying process of the second substrate W2 to the control unit of the substrate cleaning apparatus 70 via the output unit 214 (step S56).

[0132] On the other hand, when the second vibration frequency measurement value is less than the first vibration frequency measurement value 213a (step S54: NO), it is determined that the end point of the cleaning process has not been reached (step S57). Then, the control signal transmission unit 212d transmits a second control signal for continuing the cleaning process of the second substrate W2 to the control unit of the substrate cleaning apparatus 70 via the output unit 214 (step S58).

[0133] According to the present embodiment as described above, for the substrates after the second substrate W2, it is possible to determine the cleanliness for any number of substrates to be processed (including all substrates) that are continuously introduced into the scrub cleaning process without the need for evaluation by the defect inspection apparatus 70 after cleaning. Moreover, since the amount of contaminants is measured based on the measurement of the vibration frequency of the crystal oscillator, it is possible to detect even very small amounts of contaminants. By determining the cleanliness of the drain 40 based on the measurement result and determining the cleanliness of the substrate W based on the determination result, it is less likely to misjudge a substrate W with remaining contaminants as "clean". As a result, for the substrates after the second substrate W2, it is possible to more timely and accurately determine the cleanliness of the substrate W while suppressing a decrease in throughput during cleaning without requiring evaluation by the defect inspection apparatus for all substrates after cleaning.

[0134] (Fifth Embodiment) FIG. 12A is a schematic diagram showing the configuration of a substrate cleaning apparatus 70 according to a fifth embodiment. As shown in FIG. 12A, the substrate cleaning apparatus 70 includes a housing 71, a rotary holding unit 72, cleaning members 73 and 74, cleaning liquid nozzles 78 and 79, a self-cleaning device 80, a QCM sensor 84, a pump 83, and a determination device 75.

[0135] Among these, the housing 71 houses the substrate W to be cleaned inside and prevents the cleaning liquid from scattering outside during the cleaning of the substrate W. The rotary holding unit 72 is, for example, a rotary roller, holds the outer edge portion of the substrate W in the housing 71, and rotates the substrate W around its central axis. The cleaning liquid nozzles 78 and 79 are disposed in the housing 71 and supply the cleaning liquid for substrate cleaning to the front and back surfaces of the substrate W held by the rotary holding unit 72, respectively.

[0136] The cleaning members 73 and 74 have a roll shape, are disposed in the housing 71, and contact and scrub-clean the front and back surfaces of the substrate W held by the rotary holding unit 72, respectively. As the cleaning members 73 and 74, for example, PVA (polyvinyl alcohol) brushes are used.

[0137] The self-cleaning device 80 is disposed in the housing 71 and performs self-cleaning of the cleaning members 73 and 74 by releasing contaminants from the cleaning members 73 and 74 into the cleaning liquid for self-cleaning during the break-in process (conditioning process) of the cleaning members 73 and 74 or after the scrub cleaning of the substrate W. As the cleaning liquid for self-cleaning, for example, pure water, ammonia water, an aqueous solution containing a cleaning liquid, etc. are used.

[0138] In the example shown in FIG. 12A, the self-cleaning device 80 has a water tank 81 that stores a cleaning liquid for self-cleaning, and a plate-shaped self-cleaning member 82 disposed in the cleaning liquid in the water tank 81. During the break-in process (conditioning process) of the cleaning members 73 and 74, or after the scrub cleaning of the substrate W, the cleaning members 73 and 74 are immersed in the cleaning liquid in the water tank 81, and while the cleaning members 73 and 74 are rotated about their central axes, the self-cleaning member 82 is pressed against the surfaces of the cleaning members 73 and 74, so that the contaminants adhering to the surfaces of the cleaning members 73 and 74 are released into the cleaning liquid.

[0139] As a modified example, as shown in FIG. 13B, the self-cleaning device 80 has an injection nozzle 85 that injects a cleaning liquid for self-cleaning and a self-cleaning member 82. While the cleaning member 73 is rotated about its central axis, the cleaning liquid is injected from the injection nozzle 85 toward the surface of the cleaning member 73, and the self-cleaning member 82 is pressed against the surface of the cleaning member 73, so that the contaminants adhering to the surface of the cleaning member 73 may be released into the cleaning liquid. In this case, the drainage containing the contaminants is stored in the drainage drain 86.

[0140] As another modified example, as shown in FIG. 13C, the self-cleaning device 80 has an inner rinse means 86 that supplies a cleaning liquid for self-cleaning to the inside of the cleaning member 73 and a self-cleaning member 82. While the cleaning member 73 is rotated about its central axis, the cleaning liquid flows into the inside of the cleaning member 73 from the inner rinse means 86, the cleaning liquid flows out from the surface of the cleaning member, and the self-cleaning member 82 is pressed against the surface of the cleaning member 73, so that the contaminants that have entered the inside of the cleaning member 73 and the contaminants adhering to the surface of the cleaning member 73 may be released into the cleaning liquid. Also in this case, the drainage containing the contaminants is stored in the drainage drain 86.

[0141] The QCM sensor 84 is disposed within the housing 71 and positioned adjacent to the self-cleaning device 80. In the examples shown in FIGS. 12A, 13B, and 13C, the QCM sensor 84 is disposed in the atmosphere with the electrodes of the crystal oscillator oriented horizontally upward, but is not limited thereto. As shown in FIGS. 13A and 13D, it may be disposed with the electrodes oriented vertically sideways. Although not shown, it may also be disposed with the electrodes oriented horizontally downward. The horizontally downward orientation is preferred because it can prevent the drained liquid scattered during self-cleaning from adhering to the electrodes. In the case of the vertically sideways orientation, it is preferably oriented outward with respect to the cleaning tank 71 so that the drained liquid scattered during self-cleaning does not adhere to the electrodes. When it is oriented horizontally upward or vertically sideways and inward with respect to the cleaning device 71, it is preferably provided with an openable and closable shutter (not shown) to cover the electrodes so that the drained liquid scattered during self-cleaning does not adhere to the electrodes.

[0142] The pump 83 sucks the cleaning liquid (the drained liquid after self-cleaning) in the water tank 71 or the drained liquid in the drain 86 and discharges and contacts it onto the electrodes of the crystal oscillator of the QCM sensor 84. As the pump 83, for example, a liquid feed pump may be used, or a syringe pump may be used. As a modified example, instead of the pump 83, lifting means (not shown) may be provided, and the lifting means may contact the drained liquid onto the electrodes of the crystal oscillator by immersing the QCM sensor 84 in the cleaning liquid (the drained liquid after self-cleaning) in the water tank 71 or the drained liquid in the drain 86 and then pulling it up into the atmosphere.

[0143] In the examples shown in FIGS. 12A and 13A to 13D, the QCM sensor 84 was disposed in the atmosphere, but is not limited thereto. As shown in FIGS. 13E to 13K, the QCM sensor 84 may be disposed in the drain liquid for self-cleaning. For example, when the self-cleaning device 80 has a water tank 81 for storing the cleaning liquid for self-cleaning, the QCM sensor 84 may be disposed at a position lower than the liquid level of the cleaning liquid in the water tank 81 as shown in FIG. 13E. Further, when the self-cleaning device 80 has an injection nozzle 85 for injecting the cleaning liquid for self-cleaning, the QCM sensor 84 may be disposed in the drain 86 as shown in FIG. 13F, or may be disposed below the cleaning member 73 on the self-cleaning member 82 as shown in FIG. 13G, or may be disposed on the bottom plate 87 between the self-cleaning member 73 and the drain 76 as shown in FIG. 13H. Further, when the self-cleaning device 80 has an inner rinse means 86 for supplying the cleaning liquid for self-cleaning to the inside of the cleaning member 73, the QCM sensor 84 may be disposed in the drain 86 as shown in FIG. 13I, or may be disposed below the cleaning member 73 on the self-cleaning member 82 as shown in FIG. 13J, or may be disposed on the bottom plate 87 between the self-cleaning member 73 and the drain 76 as shown in FIG. 13K.

[0144] As shown in FIGS. 13E to 13K, when the QCM sensor 84 is disposed in the drain liquid for self-cleaning, an adsorption film that adsorbs by the action of one or both of chemisorption (adsorption by hydrogen bonding) and physical adsorption (adsorption by van der Waals force) of contaminants may be fixed on the electrode of the crystal oscillator of the QCM sensor 84.

[0145] Incidentally, the manufacturing method of the PVA brush is generally as follows. That is, first, polyvinyl alcohol is dissolved in warm water to prepare an aqueous polyvinyl alcohol solution of about 5 to 15% by weight. Then, a solution in which starch, which is a pore-forming material, is dispersed in water is added thereto. After heating this solution to around the gelatinization temperature of starch, an aqueous solution of sulfuric acid and formaldehyde is further added, and then it is thoroughly stirred and mixed to form a uniform slurry-like stock solution. A certain amount of this stock solution is poured into a predetermined mold. It is allowed to react at about 60 °C for 10 hours or more. After the reaction is completed, it is pressed and washed with water, whereby unreacted aldehydes, acids, and fine starch powders are removed, and it peels off to obtain a sponge sheet (PVA brush) made of a polyvinyl acetal-based porous body. The saponification degree of polyvinyl alcohol is 97% or more, the polymerization degree of polyvinyl alcohol is 300 to 2000, and the acetalization degree is 50 to 80%. When the acetalization degree exceeds 80%, it is hard even when wetted with water and is not suitable for use. In the PVA brush thus obtained, finally, 50 to 80% of acetal groups and 20 to 50% of OH groups (hydroxy groups) are present. The surface physical properties of the PVA brush are greatly affected by the action of this OH group (hydroxy group).

[0146] The contaminants released from the cleaning member (PVA brush) include: (1) those resulting from the cleaning member cleaning process, (2) those due to contamination from the equipment, and (3) those released after wafer cleaning. Among these, more specifically, for (1) those resulting from the cleaning member cleaning process, there are pore-forming materials (such as starch fine powder), sponge sheet materials made of resin porous bodies (cross-linked molecules and uncross-linked molecules of polyvinyl acetal, etc.), and other raw materials (such as polyvinyl alcohol and aldehyde). Also, for (2) those due to contamination from the equipment, more specifically, there are housing metals, paints, structural resins, etc. Further, for (3) those released after wafer cleaning, more specifically, there are wafer polishing pieces (such as silica oxide, wiring metal / barrier metal, compounds of metal and chemical solution, etc.), those derived from polishing chemicals (such as corrosion inhibitors and cleaning agents), and those derived from the deterioration of the cleaning member (sponge sheet materials made of resin porous bodies (cross-linked molecules and uncross-linked molecules of polyvinyl acetal, etc.)). Among these, the pore-forming materials (such as starch fine powder) and the sponge sheet materials made of resin porous bodies (cross-linked molecules and uncross-linked molecules of polyvinyl acetal, etc.) become substances for judging the completion of the break-in process of the cleaning member and the timing of deterioration replacement.

[0147] Therefore, as the adsorption film, for example, a film that selectively adsorbs starch or polyvinyl acetal from among the above contaminants may be used. Specifically, for example, the adsorption film may be any one or two or more of the following: (a) a molecular film composed of an alkyl chain of an appropriate length (for example, C = 6 to 40) or an alkyl chain having a functional group (hydroxy group, carboxyl group, etc.); (b) a molecular film in which the functional group is located at the end or middle of the alkyl chain or at the end or middle of a branched alkyl chain; (c) a film in which a transition metal (Au, Pt, etc.), an oxide (SiO2), or a semiconductor is coated on the electrode surface of a QCM sensor, and a molecular chain is fixed on the surface by a thiol reaction or a silane coupling reaction. Here, in the case of an adsorption film that adsorbs with a functional group, both chemical adsorption and physical adsorption generally contribute at a certain ratio. On the other hand, when the molecular film consists only of an alkyl chain, physical adsorption occurs because the influence of van der Waals forces (physical forces) and hydrophobicity is large. Since the alkyl chain has a hydrophobic (difficult to form hydrogen bonds) property, water molecules do not adsorb. The contaminants released during cleaning at the time of brush raising become starch and the molecular chains of the PVA brush (including cross-linked and uncross-linked ones), and these are more likely to bind to the alkyl chain than water molecules. Also, during brush cleaning after use for polishing, inorganic substances such as abrasive grains and metal enter the contaminants, but the inorganic substances are also difficult to bind to the alkyl chain. Therefore, it is possible to selectively adsorb specific substances such as starch and polyvinyl alcohol from among the contaminants by using only physical action without using chemical reactions.

[0148] Returning to FIG. 12A, the determination device 75 is a device that determines the cleanliness of the cleaning members 74 and 75 that scrub and clean while contacting the substrate W. The determination device 75 is configured by one or more computers.

[0149] FIG. 12B is a block diagram showing the configuration of the determination device 75. As shown in FIG. 12B, the determination device 75 includes an input unit 751, a control unit 752, a storage unit 753, and an output unit 754. Each unit is connected to communicate with each other via a bus.

[0150] Among these, the input unit 751 is a communication interface between the QCM sensor 84 and the determination device 75. The input unit 751 receives data on the vibration frequency response (i.e., the vibration frequency or the phase (delay) of the vibration frequency) of the crystal oscillator output from the QCM sensor 84.

[0151] The output unit 754 is an interface that outputs various information to the user from the determination device 75, and is, for example, a video display means such as a liquid crystal display or an audio output means such as a speaker. The determination result by the cleanliness determination unit 752c described later is output to the user via the output unit 754.

[0152] The storage unit 753 is a non-volatile data storage such as a flash memory, for example. Various data handled by the control unit 752 are stored in the storage unit 753. Further, an initial value 753a of the vibration frequency response of the crystal oscillator measured by the initial value measurement unit 752a described later is recorded in the storage unit 753.

[0153] The control unit 752 is a control means for performing various processes of the determination device 75. As shown in FIG. 12B, the control unit 752 includes an initial value measurement unit 752a, a vibration frequency response measurement unit 752b, and a cleanliness determination unit 752c. Each of these units may be realized by a processor in the determination device 75 executing a predetermined program, or may be implemented in hardware.

[0154] The initial value measurement unit 752a measures the vibration frequency response of the crystal oscillator of the QCM sensor 50 before contaminants are attached to the electrodes, and records it in the storage unit 753 (recording medium) as the initial value 753a.

[0155] The vibration frequency response measurement unit 752b measures the vibration frequency response of the crystal oscillator with contaminants attached to the electrodes after the drainage of the self-cleaning device 80 comes into contact with the electrodes of the crystal oscillator of the QCM sensor 84 and the contaminants contained in the drainage are attached to the electrodes of the crystal oscillator.

[0156] The cleanliness determination unit 752c determines the cleanliness of the cleaning members 74 and 75 based on the frequency response measured by the frequency response measurement unit 752b. For example, while referring to the initial value 753a, the cleanliness determination unit 752c calculates the difference between the frequency response measured by the frequency response measurement unit 752b and the initial value 753a, and measures the amount of the object to be measured (for example, contaminants) adhering to the electrode based on the calculated difference. Then, the cleanliness determination unit 752c compares the amount of contaminants adhering to the electrode with a predetermined threshold value. When the amount of contaminants adhering to the electrode is equal to or less than the threshold value, it determines that the cleaning member is "clean", and when it is greater than the threshold value, it determines that the cleaning member is "contaminated" (contaminants remain on the cleaning member).

[0157] As a first embodiment, before the drain liquid of the self-cleaning device 80 adheres to the electrode of the crystal oscillator of the QCM sensor 84 and the drain liquid adhering to the electrode is dried, the vibration frequency response measurement unit 752b measures (a) the vibration frequency response of the crystal oscillator, and the cleaning degree determination unit 752c measures the liquid volume (X1) of the drain liquid adhering to the electrode based on the measured vibration frequency response. Alternatively, the cleaning degree determination unit 752c measures (b) the contact liquid volume (X2) by a metering facility for the volume, weight, or contact time of the drain liquid. Then, the vibration frequency response measurement unit 752b dries the drain liquid adhering to the electrode to deposit the contaminants contained in the drain liquid on the electrode of the crystal oscillator, and then measures the vibration frequency response of the crystal oscillator. The cleaning degree determination unit 752c measures the amount of contaminants (Y) deposited on the electrode based on the measured vibration frequency response, calculates the contaminant concentration (Z) of the drain liquid based on the measured drain liquid volume (X1 or X2) and the amount of contaminants (Y), and may determine the cleaning degree of the cleaning member based on the calculated contaminant concentration (Z). Here, the method of drying the drain liquid adhering to the electrode may be, for example, heating the electrode surface or constantly maintaining a temperature higher than room temperature, or spraying dry air or gas. Also, the metering facility for the volume of the drain liquid may be, for example, a volumetric liquid delivery mechanism such as a syringe pump or a peristaltic pump, or a camera that observes the shape of the liquid droplet from the side of the electrode surface. The metering facility for the weight of the drain liquid may be, for example, a mechanism that delivers liquid when a certain weight is reached by a weighing scale type mechanism. The metering facility for the contact time of the drain liquid is, for example, a timer. Since the flow rate of the liquid can be known from the volume of the liquid supplied during brush cleaning, the contact liquid volume may be measured from the flow rate of the liquid and the immersion time due to the vertical movement of the electrode surface or the immersion time due to the opening and closing of the shutter.

[0158] As a second embodiment, the frequency response measurement unit 752b measures the frequency response of the crystal oscillator after contaminants contained in the drain liquid are deposited on the electrodes of the crystal oscillator of the QCM sensor 84 and dried by allowing a predetermined amount of the drain liquid of the self-cleaning device 80 to adhere to the electrodes of the crystal oscillator. The cleanliness determination unit 752c may measure the amount of contaminants deposited on the electrodes based on the measured frequency response, and determine the cleanliness of the cleaning member based on the measured amount of contaminants.

[0159] As a third embodiment, the frequency response measurement unit 752b measures the frequency response of a crystal oscillator in which an adsorption film that adsorbs contaminants by one or both of chemisorption and physisorption is fixed on the electrodes, after the contaminants contained in the drain liquid of the self-cleaning device 80 are adsorbed on the adsorption film by immersing the crystal oscillator in the drain liquid. The cleanliness determination unit 752c may measure the amount of contaminants adsorbed on the adsorption film based on the measured frequency response, and determine the cleanliness of the cleaning member based on the measured amount of contaminants.

[0160] In the first and second embodiments, the frequency response measurement unit 752b measures the time change of the frequency response of the crystal oscillator in a state where the crystal oscillator of the QCM sensor 50 with contaminants deposited on the electrodes is immersed in a liquid (for example, pure water). The cleanliness determination unit 752c may measure the mass of the liquid-soluble contaminants based on the difference between the frequency response when the time change has saturated and the frequency response immediately after immersion in the liquid. The cleanliness determination unit 752c may calculate the mass of the liquid-insoluble contaminants based on the difference between the mass of the contaminants deposited on the electrodes and the mass of the liquid-soluble contaminants.

[0161] Next, a determination method according to the fifth embodiment will be described. FIG. 14 is a flowchart showing the determination method according to the fifth embodiment.

[0162] As shown in FIG. 14, first, the initial value measurement unit 752a measures the frequency of the crystal oscillator of the QCM sensor 50 before attaching contaminants to the electrodes, and records it in the storage unit 753 (recording medium) as the initial value 753a (step S50).

[0163] Next, during the break-in process of the cleaning members 73 and 74 or after the scrub cleaning of the substrate W, the self-cleaning device 80 discharges contaminants from the cleaning members 73 and 74 into the cleaning liquid for self-cleaning, thereby performing self-cleaning of the cleaning members 73 and 74 (step S51).

[0164] Next, the drainage of the self-cleaning device 80 is brought into contact with the electrodes of the crystal oscillator of the QCM sensor 84. After the contaminants contained in the drainage adhere to the electrodes of the crystal oscillator, the vibration frequency response measurement unit 752b measures the vibration frequency response of the crystal oscillator with contaminants adhering to the electrodes, and the cleanliness determination unit 752c determines the cleanliness of the cleaning members 73 and 74 based on the vibration frequency response measured by the vibration frequency response measurement unit 752b (step S52).

[0165] As a first embodiment of step S52, as shown in FIG. 15A, the cleanliness determination unit 752c may measure the liquid volume (X) of the drainage liquid adhering to the electrode of the crystal oscillator of the QCM sensor 84 in the self-cleaning device 80 before drying the drainage liquid adhering to the electrode (step S520). In step S520, the vibration frequency response measurement unit 752b may (a) measure the vibration frequency response of the crystal oscillator, and the cleanliness determination unit 752c may measure the liquid volume (X) of the drainage liquid adhering to the electrode based on the measured vibration frequency response. Alternatively, the cleanliness determination unit 752c may (b) measure the contact liquid volume (X) using a metering facility for the volume, weight, or contact time of the drainage liquid. Next, the vibration frequency response measurement unit 752b dries the drainage liquid adhering to the electrode to deposit the contaminants contained in the drainage liquid on the electrode of the crystal oscillator, and then measures the vibration frequency response of the crystal oscillator. The cleanliness determination unit 752c may measure the amount of contaminants (Y) deposited on the electrode based on the measured vibration frequency response (step S521). Then, the cleanliness determination unit 752c calculates the contaminant concentration (Z = Y / X) of the drainage liquid based on the measured liquid volume (X) and amount of contaminants (Y) of the drainage liquid (step S522), and may determine the cleanliness of the cleaning members 73 and 74 based on the calculated contaminant concentration (Z) (step S523).

[0166] As a second embodiment of step S52, as shown in FIG. 15B, the vibration frequency response measurement unit 752b may measure the vibration frequency response of the crystal oscillator after a predetermined amount of the drainage liquid of the self-cleaning device 80 adheres to the electrode of the crystal oscillator of the QCM sensor 84 and is dried, so that the contaminants contained in the drainage liquid are deposited on the electrode of the crystal oscillator (step S524). Next, the cleanliness determination unit 752c measures the amount of contaminants deposited on the electrode based on the measured vibration frequency response (step S525), and may determine the cleanliness of the cleaning members 73 and 74 based on the measured amount of contaminants (step S526).

[0167] As a third embodiment of step S52, as shown in FIG. 15C, a crystal oscillator with an adsorption film that adsorbs contaminants by one or both of chemical adsorption and physical adsorption fixed on an electrode is immersed in the drain liquid of the self-cleaning device 80, and after the contaminants contained in the drain liquid are adsorbed onto the adsorption film, the frequency response of the crystal oscillator may be measured (step S527). Next, the cleanliness determination unit 752c may measure the amount of contaminants adsorbed on the adsorption film based on the measured frequency response (step S528), and may determine the cleanliness of the cleaning members 73 and 74 based on the measured amount of contaminants (step S529).

[0168] In the first or second embodiment, after step S523 or S526, the frequency response measurement unit 752b measures the time change of the frequency response of the crystal oscillator of the QCM sensor 50 with contaminants deposited on the electrode while the crystal oscillator is immersed in a liquid (e.g., pure water), and the cleanliness determination unit 752c may measure the mass of the liquid-soluble contaminants based on the difference between the frequency response when the time change has saturated and the frequency response immediately after immersion in the liquid. The cleanliness determination unit 752c may calculate the mass of the liquid-insoluble contaminants based on the difference between the mass of the contaminants deposited on the electrode and the mass of the liquid-soluble contaminants.

[0169] Thereafter, as shown in FIG. 14, the contaminants are removed (reset) from the electrode of the crystal oscillator of the QCM sensor 84, and preparations for the next measurement are made (step S53). The method for removing the contaminants may be, for example, water washing or chemical solution washing, or the contaminants may be evaporated by heating.

[0170] According to the present embodiment as described above, the drainage liquid in the self-cleaning of the cleaning members 73 and 74 is brought into contact with the electrodes of the crystal oscillator, and after the contaminants contained in the drainage liquid are adhered to the electrodes of the crystal oscillator, in order to measure the frequency response of the crystal oscillator with contaminants adhered to the electrodes, it is possible to detect even very minute contaminants, and by determining the cleanliness of the cleaning members 73 and 74 based on the measurement results, it becomes less likely that the cleaning members 73 and 74 with contaminants remaining are misjudged as "clean", that is, it becomes possible to accurately determine the cleanliness of the cleaning members 73 and 74.

[0171] Also, according to the present embodiment, after bringing the drainage liquid of the self-cleaning into contact with the electrodes of the crystal oscillator and adhering the contaminants contained in the drainage liquid to the electrodes of the crystal oscillator, measuring the frequency response of the crystal oscillator with contaminants adhered to the electrodes is performed while the crystal oscillator is disposed in the housing 71 where the scrub cleaning of the substrate W is performed. Therefore, it is possible to quickly determine the cleanliness of the cleaning members 73 and 74 in-line, and it is also possible to confirm the change over time of the cleanliness and predict the deterioration replacement timing of the cleaning members 73 and 74 based on that.

[0172] As described above, the embodiments and modified examples have been explained by way of illustration, but the scope of the present technology is not limited to these, and it is possible to make changes and modifications according to the purpose within the scope described in the claims. For example, the method for evaluating the contamination degree of the cleaning member according to one embodiment can also be applied to an improved break-in process and an improved pre-shipment inspection of the cleaning member. Also, each embodiment and modified example can be appropriately combined within a range where the processing contents do not conflict.

[0173] Also, the determination device 10 according to the present embodiment can be configured by one or more computers, but a program for realizing the determination device 10 on one or more computers and a recording medium that non-temporarily records the program are also the protection objects of this case.

Explanation of Reference Numerals

[0174] 10 Determination device 11 Input unit 12 Control unit 12a Initial value measurement unit 12b Pollutant mass measurement unit 12c Cleanliness determination unit 13 Memory unit 13a Initial value 14 Output unit 20 Liquid 21 First crystal oscillator 22 Second crystal oscillator 31 Cleaning member 40 Drainage 41 Drainage pipe 42 Branch pipe 50 QCM sensor 60 Defect inspection device 70 Substrate cleaning device 100 Determination device 111 Input unit 112 Control unit 112a Vibration frequency measurement unit 112b Drainage cleanliness determination unit 112c Substrate cleanliness determination unit 113 Memory unit 113a Vibration frequency measurement value 114 Output unit 200 Determination device 211 Input unit 212 Control unit 212a Cleaning process end recording unit 212b Vibration frequency measurement unit 212c End point determination unit 212d Control signal transmission unit 213 Memory unit 213a Vibration frequency measurement value 214 Output unit W Substrate

Claims

A method for determining the cleanliness of a cleaning member that scrub-cleans in contact with a substrate, comprising: A first step of performing self-cleaning of the cleaning member by releasing contaminants from the cleaning member into the cleaning liquid; A second step of bringing the drainage of the self-cleaning into contact with the electrode of a crystal oscillator, attaching the contaminants contained in the drainage to the electrode of the crystal oscillator, then measuring the vibration frequency response of the crystal oscillator with contaminants attached to the electrode, and determining the cleanliness of the cleaning member based on the measured vibration frequency response; and In the second step, before the drainage of the self-cleaning is attached to the electrode of the crystal oscillator and the drainage attached to the electrode is dried, (a) the vibration frequency response of the crystal oscillator is measured, and based on the measured vibration frequency response, the liquid volume of the drainage attached to the electrode is measured, or (b) the contact liquid volume is measured by a metering facility for the volume or weight or contact time of the drainage, and then the drainage attached to the electrode is dried to deposit the contaminants contained in the drainage on the electrode of the crystal oscillator, then the vibration frequency response of the crystal oscillator is measured, and based on the measured vibration frequency response, the amount of contaminants deposited on the electrode is measured, and based on the measured liquid volume and amount of contaminants of the drainage, the contaminant concentration of the drainage is calculated, and based on the calculated contaminant concentration, the cleanliness of the cleaning member is determined. A method characterized by the above. A method for determining the cleanliness of a cleaning member that scrub-cleans in contact with a substrate, comprising: A first step of performing self-cleaning of the cleaning member by releasing contaminants from the cleaning member into the cleaning liquid; A second step of bringing the drainage of the self-cleaning into contact with the electrode of a crystal oscillator, attaching the contaminants contained in the drainage to the electrode of the crystal oscillator, then measuring the vibration frequency response of the crystal oscillator with contaminants attached to the electrode, and determining the cleanliness of the cleaning member based on the measured vibration frequency response; including, in the second step, depositing a predetermined amount of the drainage of self-cleaning on the electrode of the crystal oscillator and drying it to deposit contaminants contained in the drainage on the electrode of the crystal oscillator, then measuring the frequency response of the crystal oscillator, measuring the amount of contaminants deposited on the electrode based on the measured frequency response, and determining the cleanliness of the cleaning member based on the measured amount of contaminants. A method characterized by the above.

3. A method for determining the cleanliness of a cleaning member that scrub-cleans in contact with a substrate, including a first step of performing self-cleaning of the cleaning member by releasing contaminants into the cleaning liquid from the cleaning member, contacting the drainage of self-cleaning on the electrode of the crystal oscillator, attaching contaminants contained in the drainage to the electrode of the crystal oscillator, then measuring the frequency response of the crystal oscillator with contaminants attached to the electrode, and a second step of determining the cleanliness of the cleaning member based on the measured frequency response. including, in the second step, immersing a crystal oscillator with an adsorption film fixed on the electrode that adsorbs contaminants by one or both of chemisorption and physisorption in the drainage of self-cleaning, adsorbing contaminants contained in the drainage on the adsorption film, then measuring the frequency response of the crystal oscillator, measuring the amount of contaminants adsorbed on the adsorption film based on the measured frequency response, and determining the cleanliness of the cleaning member based on the measured amount of contaminants. A method characterized by the above.

4. A third step of immersing a crystal oscillator with contaminants deposited on the electrode in a liquid, measuring the time change of the frequency response of the crystal oscillator, and measuring the mass of the liquid-soluble contaminants based on the difference between the frequency when the time change reaches saturation and the frequency response immediately after immersion in the liquid. The method according to claim 1 or 2, further comprising the above.

5. A step of calculating the mass of the liquid-insoluble contaminants based on the difference between the mass of the contaminants deposited on the electrode and the mass of the liquid-soluble contaminants. The method according to claim 4, further comprising **Claim 6** wherein the liquid is pure water, aqueous ammonia, or an aqueous solution containing a cleaning liquid, characterizing the method according to claim 4 or 5. **Claim 7** In the first step, in the housing where the scrub cleaning of the substrate is performed, the cleaning member is self-cleaned by releasing contaminants into the cleaning liquid from the cleaning member, in the second step, in the housing, the drainage of the self-cleaning is brought into contact with the electrode of the crystal oscillator, and after the contaminants contained in the drainage are adhered to the electrode of the crystal oscillator, the frequency response of the crystal oscillator with contaminants adhered to the electrode is measured while the crystal oscillator is disposed in the housing, and based on the measured frequency response, the cleanliness of the cleaning member is determined. characterizing the method according to any one of claims 1 to 6. **Claim 8** In the first step, the cleaning member is immersed in the cleaning liquid, and contaminants are released from the cleaning member into the cleaning liquid characterizing the method according to any one of claims 1 to 7. **Claim 9** In the first step, the cleaning liquid is sprayed toward the surface of the cleaning member, and contaminants are released from the cleaning member into the cleaning liquid characterizing the method according to any one of claims 1 to 7. **Claim 10** In the first step, the cleaning liquid flows into the inside of the cleaning member, and the cleaning liquid flows out from the surface of the cleaning member, thereby releasing contaminants from the cleaning member into the cleaning liquid characterizing the method according to any one of claims 1 to 7. **Claim 11** A method for determining the adsorption characteristics of contaminants that contaminate a cleaning member that scrub-cleans in contact with a substrate, immersing the cleaning member in pure water and releasing contaminants from the cleaning member into the pure water, A first crystal oscillator having a first substance with a first zeta potential formed on an electrode and a second crystal oscillator having a second substance with a second zeta potential different from the first zeta potential formed on an electrode are immersed in pure water containing a pollutant, the frequency responses of the first crystal oscillator and the second crystal oscillator are measured, and based on the difference in the time change of the frequency responses, a step of determining the adsorption characteristics of the pollutant; A method characterized by including the above.

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