JP2011077135A - Method of determining ultrasonic cleaning condition of substrate, and substrate cleaning device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress damages to a substrate pattern in ultrasonic cleaning. <P>SOLUTION: After determining optimum cleaning conditions where an output of (1/2) f becomes not more than an output value with a treatment liquid as degassed water, a control section 57 operates each section so that the optimum cleaning conditions are attained, thus performing cleaning treatment with respect to a substrate W of a product and hence suppressing a poor influence by subharmonics of (1/2) f and suppressing damages to a pattern of the substrate W at ultrasonic cleaning. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for determining ultrasonic cleaning conditions for a substrate such as a semiconductor wafer or a glass substrate for a liquid crystal display device (hereinafter simply referred to as a substrate) by ultrasonic vibration, and a substrate cleaning apparatus using the same. .

  Conventionally, as this type of apparatus, a treatment tank that stores a treatment liquid in which an inert gas is dissolved, a propagation tank that stores propagation water, and a lower part of the treatment tank is disposed at a position where it is immersed in the propagation water, Examples include an ultrasonic vibrator attached to a tank, and a lifter that supports a substrate and moves up and down over a standby position above the processing tank and a cleaning position inside the processing tank (for example, Patent Documents). 1 and 2).

  In such an apparatus, the ultrasonic vibration is applied to the propagation water from the ultrasonic vibrator while the lifter is lowered to the cleaning position and the substrate is immersed in the processing liquid. Then, ultrasonic vibration is transmitted to the processing liquid in the processing tank, and the substrate immersed in the processing liquid is cleaned.

  In such ultrasonic cleaning, a physical cleaning effect can be obtained by impact energy generated by cavitation in which extremely small bubbles are rapidly formed in the processing liquid or are violently collapsed. Specifically, the bubbles in the treatment liquid are crushed when they grow to the resonant bubble diameter.

JP 2009-032710 A JP 2007-288134 A

However, the conventional example having such a configuration has the following problems.
That is, in recent years, for example, with the increase in capacity of memory chips, the pattern formed on the substrate has been miniaturized. Therefore, there is a problem that damage to the pattern of the substrate becomes obvious during ultrasonic cleaning. Such a problem causes a decrease in the yield of the product, so that there is an urgent need to solve it.

  The present invention has been made in view of such circumstances, and a substrate ultrasonic cleaning condition determination method capable of suppressing damage to a substrate pattern during ultrasonic cleaning and substrate cleaning using the same An object is to provide an apparatus.

As a result of intensive studies to solve the above problems, the present inventor has obtained the following knowledge.
Since an output from an ultrasonic oscillator that can output an arbitrary frequency is given to the ultrasonic vibrator, ultrasonic vibration of an arbitrary frequency can be applied to the treatment liquid. By the way, if bubbles exist in the processing liquid, secondary ultrasonic waves having a frequency of (1 / n) times different from the oscillation frequency f given from the ultrasonic oscillator using the bubbles as a sound source. Is known to be triggered. This is called “sub-harmonic” (subharmonic), and the output of the sub-harmonic is very small compared to the oscillation frequency applied from the ultrasonic transducer. However, as a result of examining the influence of sub-harmonics on the substrate, the inventors have found the following.

  Reference is now made to the graph of FIG. FIG. 2 is a graph showing the results of measuring the intensity of (1/2) f and the number of pattern damage while changing the concentration of IPA (isopropyl alcohol) added to pure water. In the measurement, a substrate on which a fine pattern was formed was used, the substrate was immersed in a processing solution and subjected to a cleaning process for a predetermined time, and then pattern damage on the substrate was counted. Using pure water as the treatment liquid, changing the amount of IPA (isopropyl alcohol) added to the pure water, measuring the output of the subharmonic having a frequency ½ of the oscillation frequency f with an FFT analyzer, The number of pattern damage was measured. Then, a strong correlation was recognized between the output of the (1/2) f subharmonic and the number of damages. Note that, when the IPA concentration is changed, the surface tension of pure water is lowered, so that it is considered that bubbles during processing are suppressed and subharmonics change.

  Furthermore, reference is made to the graph of FIG. FIG. 3 is a graph showing the results of measuring the strength of (1/2) f and pattern damage while changing the concentration of ethylene glycol added to pure water. Also from this result, it was found that there is a strong correlation between the output of the subharmonic of (1/2) f and the number of damages.

  From the above experimental results, the inventors have found that the substrate pattern damage can be suppressed by changing the processing conditions and suppressing subharmonics.

  The present invention based on such knowledge is configured as follows.

  That is, according to the first aspect of the present invention, the substrate is cleaned by immersing the substrate in the processing solution in which the gas is dissolved, and applying ultrasonic vibration of the frequency f to the processing solution by the ultrasonic vibration applying means. In the sonic cleaning condition determination method, the output of the (1/2) f subharmonic generated in the processing liquid is set to be equal to or lower than the output value when the processing liquid is degassed water.

  [Operation / Effect] According to the first aspect of the present invention, the condition that the output of the (1/2) f subharmonic generated in the processing liquid is equal to or lower than the output value when the processing liquid is deaerated water. Perform ultrasonic cleaning of the substrate. Therefore, the adverse effect of (1/2) f subharmonics can be suppressed, and damage to the substrate pattern during ultrasonic cleaning can be suppressed.

  In the present invention, it is preferable to adjust at least one of the frequency f of ultrasonic vibration applied to the treatment liquid, the amount of dissolved gas in the treatment liquid, the kind of treatment liquid, and the solvent mixed in the treatment liquid. (Claim 2). By adjusting these conditions, the output of the (1/2) f subharmonic generated in the treatment liquid can be made equal to or less than the output value when the treatment liquid is degassed water. Therefore, the location to be adjusted can be appropriately selected depending on the configuration of the utility and the apparatus, and the application range can be widened.

In the present invention, in addition to the above conditions, when the treatment liquid contains pure water, the saturation rate corresponding to the temperature of the treatment liquid is 0.5 or more and the watt density of ultrasonic vibration is It is preferable that it is 0.3 W / cm ² or less (Claim 3). If the saturation rate is less than 0.5 and the proportion of dissolved gas is too small, the particle removal rate may decrease, which is inappropriate for cleaning, and the watt density exceeds 0.3 W / cm ² . Even if subharmonics are suppressed, there is a risk of damage to the substrate pattern. Therefore, by adding these conditions, it is possible to suppress damage while performing appropriate cleaning.

  In the present invention, the solvent to be mixed is IPA (isopropyl alcohol), and the concentration is preferably in the range of 1 to 10% by weight. When IPA is mixed, sub-harmonics cannot be suppressed if it is less than 1% by weight, and if it exceeds 10% by weight, there is a risk of damage to the substrate pattern due to bubbles in the IPA. Therefore, appropriate cleaning can be performed by setting the concentration in the range of 1 to 10% by weight.

  The solvent to be mixed is EG (ethylene glycol), and the concentration is preferably in the range of 10 to 30% by weight (Claim 5). When EG is mixed, if it is less than 10% by weight, the sub-harmonics cannot be suppressed, and if it exceeds 30% by weight, there is a possibility that the pattern of the substrate is damaged by bubbles in the EG. Therefore, appropriate cleaning can be performed by setting the concentration in the range of 10 to 30% by weight.

  According to a sixth aspect of the present invention, in the substrate cleaning apparatus for cleaning the substrate by applying ultrasonic vibration, a processing tank for storing the processing liquid, a processing position that holds the substrate and corresponds to the inside of the processing tank, A holding means that moves up and down over a standby position above the treatment tank, a propagation tank that stores propagation water that is a propagation medium of ultrasonic vibration, and that is disposed at a position where the bottom of the treatment tank is immersed in propagation water; , Ultrasonic vibration applying means for applying ultrasonic vibration of frequency f with an arbitrary output to the propagation water disposed in the propagation tank and stored in the propagation tank, and supplying a treatment liquid to the treatment tank A treatment liquid supply means, a gas dissolution means for dissolving a gas in the treatment liquid from the treatment liquid supply means, a solvent mixing means for mixing a solvent in the treatment liquid, and an ultrasonic wave disposed in the treatment tank. Detection means for detecting vibration components The analysis means for analyzing the frequency and output of the ultrasonic vibration based on the output of the detection means, the dissolved amount of the gas by the gas dissolving means, and the mixing amount of the solvent by the solvent mixing means, The frequency f of the ultrasonic vibration applying means is varied within a predetermined range, and the subharmonic output of (1/2) f is less than or equal to the output value when the treatment liquid is deaerated water based on the analysis result by the analyzing means. And a control unit that operates each part under the optimal cleaning condition to perform a cleaning process on the substrate.

  [Operation / Effect] According to the invention described in claim 6, the frequency of the ultrasonic vibration applying means is changed by the discriminating means while changing the dissolved amount of the gas by the gas dissolving means and the mixed amount of the solvent by the solvent mixing means. f is varied within a predetermined range, and the optimum cleaning condition is determined based on the analysis result by the analysis means so that the output of (1/2) f sub-harmonics is equal to or less than the output value when the treatment liquid is degassed water. . Then, each control means operates each part under the optimum cleaning conditions to perform the cleaning process on the substrate, thereby suppressing the adverse effect due to (1/2) f sub-harmonics, and at the time of ultrasonic cleaning. Damage to the pattern of the substrate can be suppressed.

  Moreover, in this invention, it has the deaeration means which removes gas from the propagation water supplied to the said propagation tank, The said process liquid supply means supplies the propagation water deaerated by the said deaeration means as said process liquid (Claim 7). Since the propagation water deaerated by the deaeration means is used as the treatment liquid, the amount of dissolved gas in the treatment liquid can be adjusted with high accuracy.

  According to the ultrasonic cleaning condition determination method for a substrate according to the present invention, the condition that the output of the (1/2) f subharmonic generated in the processing liquid is equal to or less than the output value when the processing liquid is deaerated water. Perform ultrasonic cleaning of the substrate. Therefore, the adverse effect of (1/2) f subharmonics can be suppressed, and damage to the substrate pattern during ultrasonic cleaning can be suppressed.

It is a graph which shows the frequency of the sound in the beaker which has stored IPA of various concentrations in pure water. It is a graph which shows the result of having measured the intensity | strength of (1/2) f and pattern damage, changing the density | concentration of the isopropyl alcohol added to the pure water. It is a graph which shows the result of having measured the intensity | strength of (1/2) f and pattern damage, changing the density | concentration of the ethylene glycol added to the pure water. It is a map which shows the generation | occurrence | production defect point, (a) is a case where it is only dissolved gas, (b) is a case where IPA is mixed with dissolved gas. It is a schematic block diagram of the board | substrate cleaning apparatus which concerns on an Example.

<Method>
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a graph showing the frequency of sound in a beaker storing various concentrations of IPA in pure water.

  The inventor measured the frequency of sound in the beaker with an FFT analyzer while storing the treatment liquid in the beaker and applying ultrasonic vibration with a frequency of 730 kHz to the beaker. The treatment liquid is a mixture of pure water that has been degassed, pure water in which nitrogen gas has been dissolved, and IPA in which nitrogen gas has been dissolved and 1 to 50% by weight (hereinafter referred to as wt%). And those in which nitrogen gas is dissolved and only IPA. In FIG. 1, pure water only is expressed as Background, deaerated water is expressed as 0 wt%, and IPA dissolved is 1 wt%, 5 wt%, 10 wt%, 20 wt%, 30 wt%, 50 wt%. And only IPA is indicated as 100 wt%.

  With degassed water, the (1/2) f subharmonic peak could not be clearly confirmed. On the other hand, when nitrogen gas is dissolved, the peak of the (1/2) f subharmonic using bubbles as a sound source can be clearly confirmed. In addition, it can be confirmed that the intensity of the peak value varies according to the concentration of IPA. In particular, when the IPA concentration is in the range of 1 wt% to 10 wt%, it was found that the (1/2) f subharmonic output value can be suppressed more than the background output value. That is, it was found that the peak output value of (1/2) f can be suppressed below the output value of (1/2) f in the case of deaerated water.

  In addition, when the influence of subharmonics on the substrate was examined, the following results were obtained.

  Reference is now made to FIG. FIG. 2 is a graph showing the results of measuring the intensity of (1/2) f and the number of pattern damage while changing the concentration of isopropyl alcohol added to pure water.

  For the measurement, a substrate on which a fine pattern was formed was used, the substrate was immersed in a processing solution, washed for a predetermined time, and then the pattern damage of the substrate was counted. Pure water in which nitrogen gas is dissolved is used as the treatment liquid, and the output of the subharmonic having a frequency ½ of the oscillation frequency f is changed to an FFT analyzer while changing the amount of IPA (isopropyl alcohol) added to the pure water. The number of substrate damages was measured. The result is a graph shown in FIG. 2, and a strong correlation is recognized between the output of (1/2) f and the damage. Moreover, it can be seen that it depends on the concentration of IPA. That is, the strength of (1/2) f can be suppressed by setting the IPA concentration in the range of 1 wt% to 10 wt%. The degree of this suppression is below the output value of (1/2) f in deaerated water.

  Further, in the same experiment as described above, FIG. 3 shows the result when EG (ethylene glycol) is used instead of IPA as the solvent.

  As is clear from this graph, a strong correlation is recognized between the output of (1/2) f and the damage. Further, as described above, it depends on the EG concentration. In other words, it can be seen that by setting the EG concentration in the range of 10 wt% to 30 wt%, the output of (1/2) f can be suppressed below the output value of (1/2) f in the deaerated water.

  From the above experimental results, the surface tension of pure water is reduced by adding a solvent such as isopropyl alcohol or ethylene glycol to the pure water. As a result, it is presumed that bubbles during the process are suppressed and the output of (1/2) f is suppressed.

Next, the inventor conducted an experiment using a 300 mm diameter wafer on which a 37 nm pattern was formed in order to confirm the relationship between the particle removal rate, pattern damage, and (1/2) f. The wafer was cleaned by SC1 cleaning and then contaminated with 78 nm SiO ₂ particles by a spin coater. Thereafter, ultrasonic cleaning was performed with pure water in which nitrogen gas (17 ppm) was dissolved. IPA was not added to one, and 1 wt% IPA was added to the other. After cleaning for the same time, the result of measuring the particle removal rate with a light scattering defect inspection apparatus was as follows.

Particle removal rate (%) Number of damage (months)
No IPA 79.9 3096
IPA mixing 66.8 24

  Thus, it was found that by mixing IPA with pure water, damage can be suppressed without reducing the particle removal rate.

  Note that FIG. 4 compares the defect occurrence states of the wafers at that time. FIG. 4 is a map showing the generated defect points, where (a) shows the case of only dissolved gas, and (b) shows the case of mixing dissolved gas with IPA. The generated defect points are classified as damage or particles.

  From both maps, adding IPA to pure water shows the possibility of dramatically reducing damage while maintaining the particle removal rate.

  In order to make the output of (1/2) f equal to or less than the output value of (1/2) f of deaerated water, as described above, a solvent such as IPA or EG is added to pure water as the treatment liquid. In addition to mixing, it is possible to adjust any one of the frequency f of the ultrasonic vibration, the dissolved gas amount of the processing liquid, and the type of the processing liquid. That is, the same result as described above can be obtained by adjusting at least one of these parameters.

Also, from the viewpoint of clean cleaning of the substrate, when the treatment liquid contains pure water, the saturation rate corresponding to the temperature of the treatment liquid is 0.5 or more and the watt density of ultrasonic vibration is It is preferably 0.3 W / cm ² or less. If the saturation rate of pure water is less than 0.5, the proportion of dissolved gas is too small, and the particle removal rate may decrease, which is inappropriate for cleaning. If the watt density exceeds 0.3 W / cm ² , the substrate pattern may be damaged by the output of the ultrasonic wave even if the subharmonics are suppressed. Therefore, by adding these conditions, it is possible to suppress damage while performing appropriate cleaning.

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

  (1) In the above-described embodiments, IPA and EG are exemplified as the solvent. However, the solvent is not limited to these as long as it can be used for cleaning the substrate. For example, HFE (hydrofluoroether) can also be used.

  (2) In the above-described embodiment, parameters such as the frequency f and the amount of dissolved gas are adjusted so that the output of (1/2) f is less than the background output value. You may make it adjust.

<Device>
An apparatus suitable for carrying out the above-described method according to the present invention will be described with reference to the drawings. FIG. 5 is a schematic configuration diagram of the substrate cleaning apparatus according to the embodiment.

  The substrate cleaning apparatus according to the embodiment is a so-called batch type apparatus that collectively cleans a plurality of substrates W. In the following description, the plurality of substrates W are simply referred to as substrates W.

  The processing tank 1 includes an inner tank 3 and an outer tank 5. The inner tank 3 stores the processing liquid and accommodates the substrate W. The outer tank 5 is disposed outside the inner tank 3 and collects the processing liquid overflowing from the inner tank 3. The inner tank 3 includes a pair of ejection pipes 7 at the bottom. The pair of ejection pipes 7 are arranged in a posture in which the long axis is directed in the depth direction of the paper surface, and a plurality of ejection ports (not shown) are formed on the outer periphery. The pair of ejection pipes 7 supplies the processing liquid from the ejection port to the inner tank 3.

  A lifter 9 is disposed in the inner tank 3. The lifter 9 holds the substrate W in an upright posture. The lifter 9 is configured to be movable up and down over a “standby position” that is above the inner tank 3 and a “processing position” that is inside the inner tank 3.

  The lifter 9 corresponds to the “holding means” in the present invention.

  A propagation tank 11 is disposed below the inner tank 3. The propagation tank 11 stores propagation water serving as a propagation medium for ultrasonic vibration. The propagation tank 11 is provided at a position where the bottom of the inner tank 3 is immersed in the stored propagation water. An ultrasonic transducer 13 is attached to the bottom of the propagation tank 11. The ultrasonic vibrator 13 applies ultrasonic vibrations to the propagation water stored in the propagation tank 11. An ultrasonic signal having a frequency f is applied to the ultrasonic transducer 13 from the ultrasonic oscillator 14. The ultrasonic transducer 13 is preferably configured to vibrate at various ultrasonic frequencies.

  The ultrasonic transducer 13 and the ultrasonic oscillator 14 correspond to “ultrasonic vibration applying means” in the present invention.

  One end side of the supply pipe 15 is connected to the pair of ejection pipes 7 described above. The other end of the supply pipe 15 is connected to a pure water supply source 17. The supply pipe 15 includes, in order from the upstream side, a deaeration unit 19, a three-way valve 21, a dissolution unit 23, a concentration meter 25, an in-line heater 27, a flow control valve 29, a mixing valve 31, and a solvent concentration meter. 32.

  One end side of two injection pipes 33 and 35 is connected to the mixing valve 31 in communication. A chemical solution supply source 37 is connected to the other end of the injection tube 33, and a solvent supply source 39 is connected to the other end of the injection tube 35. The chemical supply source 37 supplies, for example, ammonia / hydrogen peroxide solution, and the solvent supply source 39 supplies, for example, IPA (isopropyl alcohol). In addition, a flow control valve 41 is attached to the injection pipe 33, and a flow control valve 43 is attached to the injection pipe 35.

  The mixing valve 31 described above corresponds to the “solvent mixing unit” in the present invention.

  The concentration meter 25 described above measures the concentration of the gas dissolved in the pure water by the dissolved unit 23. Further, the in-line heater 27 heats the processing liquid flowing through the supply pipe 15. The processing liquid supplied from the supply pipe 15 is supplied to the inner tank 3 from the pair of ejection pipes 7, and the overflowing processing liquid is collected in the outer tank 5 and discharged through the discharge pipe 45.

  One end side of the branch pipe 47 communicates with the three-way valve 21 described above, and the other end side of the branch pipe 47 communicates with the propagation tank 11. An opening / closing valve 49 is attached to the branch pipe 47. When the three-way valve 21 is switched to the branch pipe 47 and the on-off valve 49 is opened, pure water from the pure water supply source 17 is supplied to the propagation tank 11 as propagation water. The propagation water in the propagation tank 11 is discharged through the discharge pipe 45 as necessary.

  The deaeration unit 19 performs a deaeration process on the pure water supplied from the pure water supply source 17. Specifically, the inside of the deaeration unit 19 is decompressed to remove the gas dissolved in the pure water. The dissolved unit 23 performs the reverse process of the degassing unit 19. Specifically, a predetermined amount of gas (for example, nitrogen gas) is supplied from the dissolved amount adjustment unit 51, and the gas is dissolved in pure water flowing through the supply pipe 15.

  The dissolved unit 23 and the dissolved amount adjusting unit 51 described above correspond to the “gas dissolved means” in the present invention.

  A quartz probe 53 is attached to the inner tank 3. The quartz probe 53 has a function of detecting an ultrasonic component in the processing liquid stored in the inner tank 3. The quartz probe 53 is connected to an FFT analyzer 55 (fast Fourie transform analyzer). The FFT analyzer 55 analyzes the frequency and output intensity of the ultrasonic wave based on the output of the quartz probe 55. Each part mentioned above is controlled by the control part 57 centralizedly.

  The quartz probe 53 corresponds to “detection means” in the present invention, and the FFT analyzer 55 corresponds to “analysis means” in the present invention.

  The control unit 57 operates the dissolved amount adjusting unit 51 based on the concentration signal of the concentration meter 25 to arbitrarily adjust the amount of gas dissolved in the processing liquid, and the flow control valve based on the concentration signal of the solvent concentration meter 32. 43 is operated to arbitrarily adjust the solvent concentration of the treatment liquid. In addition, the control unit 57 operates the ultrasonic oscillator 14 to adjust the frequency f and output to be applied to the ultrasonic transducer 13. In addition, a storage unit 59 is connected to the control unit 57. The control unit 57 performs measurement under various cleaning conditions according to the procedure described below, determines the optimal cleaning condition, and stores the condition in the storage unit 59. And the control part 57 implements an actual cleaning process on optimal cleaning conditions.

  The control unit 57 corresponds to the “discriminating unit” and “control unit” in the present invention.

  Next, the procedure for determining the optimum condition in the above-described apparatus will be described. Note that the background output value described above is stored in the storage unit 59 in advance.

  The control unit 57 switches the three-way valve 21 to the supply pipe 15 side, and supplies the pure water as it is to the inner tank 3 as a processing liquid. Further, the dissolved amount adjusting unit 51 is operated while referring to the output of the concentration meter 25, a predetermined amount of gas is dissolved from the dissolved unit 23, and the flow control valve 41 is operated while referring to the output of the solvent concentration meter 32. The concentration of the solvent in the pure water flowing through the supply pipe 15 is set to a predetermined value. Then, after the pure water starts to be discharged from the inner tank 3, the lifter 9 is lowered from the standby position to the processing position while holding the dummy substrate W on the lifter 9. Next, the control unit 57 operates the ultrasonic oscillator 14 to apply an ultrasonic signal having a frequency f to the ultrasonic transducer 13 with a predetermined output.

The control unit 57 adjusts parameters such as the frequency f output from the ultrasonic oscillator 14, its output, and the dissolved gas amount by the dissolved amount adjusting unit 51 while collecting the analysis results from the FFT analyzer 55. The analysis result from the FFT analyzer 55 collected at that time is referred to, and the background output value of the storage unit 59 is compared with the output value of (1/2) f in the analysis result. As a result, a condition in which (1/2) f is equal to or lower than the background output value is determined, and the condition is stored in the storage unit 59 as the optimum cleaning condition. Note that a plurality of solvent supply sources 37 may be provided, the above procedure may be executed while switching the solvent type, and the solvent type may be included as a parameter. Further, the processing liquid temperature may be included in the parameter by operating the inline heater 27. Further, when the treatment liquid contains pure water, the condition that the saturation rate corresponding to the temperature of the treatment liquid is 0.5 or more and the watt density of ultrasonic vibration is 0.3 W / cm ² or less. Is preferably added.

  Based on the optimum cleaning conditions determined in the above procedure and stored in the storage unit 59, the control unit 57 controls each unit to perform a cleaning process on the substrate W of the product. In this case, it is preferable to perform an ultrasonic cleaning process after supplying a chemical solution from the chemical solution supply source 37 and performing, for example, SC1 cleaning.

  According to the above apparatus, after determining the optimal cleaning condition that the output of (1/2) f is equal to or less than the output value when the treatment liquid is deaerated water, the control unit 57 is set to the optimal cleaning condition. Each part is operated to perform a cleaning process on the substrate W of the product. Therefore, it is possible to suppress the adverse effect due to the subharmonic of (1/2) f, and it is possible to suppress damage to the pattern of the substrate W during ultrasonic cleaning.

  Further, since the above apparatus uses the pure water degassed by the degassing unit 19 as a processing liquid, the dissolved unit 23 can accurately adjust the amount of dissolved gas in the processing liquid.

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

  (1) In the above-described embodiment, a method of supplying the processing liquid to the processing tank 1 and sequentially discharging the processing liquid is employed, but a system of circulating the processing liquid supplied to the processing tank 1 may be employed.

  (2) In the above-described embodiment, pure water from the pure water supply source 17 is supplied to the mixing valve 31 through the deaeration unit 19, and the pure water supply source 17 is shared by the propagation water and the processing liquid. You may comprise so that the piping 15 may be equipped with another pure water supply source.

W ... Substrate 1 ... Processing tank 3 ... Inner tank 5 ... Outer tank 7 ... Jet pipe 9 ... Lifter 11 ... Propagation tank 13 ... Ultrasonic vibrator 15 ... Ultrasonic oscillator 15 ... Supply piping 17 ... Pure water supply source 19 ... Desorption Gas unit 23 ... Dissolved unit 25 ... Concentration meter 31 ... Mixing valve 32 ... Solvent concentration meter 51 ... Dissolved amount adjusting unit 53 ... Quartz probe 55 ... FFT analyzer 57 ... Control unit 59 ... Storage unit

Claims (7)

In the ultrasonic cleaning condition determination method for a substrate, the substrate is immersed in a processing solution in which a gas is dissolved, and the substrate is cleaned by applying ultrasonic vibration of frequency f to the processing solution by an ultrasonic vibration applying unit.
An ultrasonic cleaning condition determination method for a substrate, characterized in that an output of (1/2) f sub-harmonic generated in the processing liquid is set to an output value or less when the processing liquid is deaerated water. The method for determining ultrasonic cleaning conditions for a substrate according to claim 1,
The ultrasonic wave of the substrate characterized by adjusting at least one of a frequency f of ultrasonic vibration applied to the processing liquid, a dissolved gas amount of the processing liquid, a type of the processing liquid, and a solvent mixed with the processing liquid. Cleaning condition determination method. In the ultrasonic cleaning condition determination method for a substrate according to claim 2,
In addition to the above conditions, when the treatment liquid contains pure water, the saturation rate corresponding to the temperature of the treatment liquid is 0.5 or more and the watt density of ultrasonic vibration is 0.3 W / cm ^2. A method for determining ultrasonic cleaning conditions for a substrate, characterized in that: In the method for determining ultrasonic cleaning conditions for a substrate according to claim 2 or 3,
The method for determining ultrasonic cleaning conditions for a substrate, wherein the solvent to be mixed is IPA (isopropyl alcohol) and the concentration is in the range of 1 to 10% by weight. In the method for determining ultrasonic cleaning conditions for a substrate according to claim 2 or 3,
The method for determining ultrasonic cleaning conditions for a substrate, wherein the solvent to be mixed is EG (ethylene glycol) and the concentration is in the range of 10 to 30% by weight. In a substrate cleaning apparatus that cleans a substrate by applying ultrasonic vibrations,
A treatment tank for storing the treatment liquid;
Holding means for holding the substrate and moving up and down over a processing position corresponding to the inside of the processing tank and a standby position corresponding to the upper side of the processing tank;
Propagation water stored as a propagation medium of ultrasonic vibration, the propagation tank disposed at a position where the bottom of the treatment tank is immersed in the propagation water,
Ultrasonic vibration applying means for applying ultrasonic vibration of frequency f to the propagation water disposed in the propagation tank and stored in the propagation tank at an arbitrary output;
Treatment liquid supply means for supplying a treatment liquid to the treatment tank;
Gas dissolving means for dissolving gas in the processing liquid from the processing liquid supply means;
Solvent mixing means for mixing a solvent with the treatment liquid;
A detecting means disposed in the processing tank for detecting a component of ultrasonic vibration;
Analysis means for analyzing the frequency and output of the ultrasonic vibration based on the output of the detection means;
While changing the dissolved amount of gas by the gas dissolving means and the mixing amount of the solvent by the solvent mixing means, the frequency f of the ultrasonic vibration applying means is varied within a predetermined range, and according to the analysis result by the analyzing means, (1/2) a discriminating means for discriminating an optimum cleaning condition in which the output of the sub-harmonic of f is equal to or less than an output value when the treatment liquid is degassed water;
Control means for operating each part under the optimum cleaning conditions to perform a cleaning process on the substrate;
A substrate cleaning apparatus comprising: The substrate cleaning apparatus according to claim 6, wherein
Comprising degassing means for removing gas from the propagation water supplied to the propagation tank;
The substrate cleaning apparatus, wherein the processing liquid supply means supplies the propagation water degassed by the degassing means as the processing liquid.

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