JP2011029455A - Apparatus and method for processing substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a processing apparatus capable of determining a concentration of a processing liquid for processing a substrate. <P>SOLUTION: The apparatus processes the substrate by the processing liquid obtained by diluting the chemical with a dilution liquid. The apparatus has an imaging camera 7 for measuring the thickness of the processing liquid supplied to the substrate and a controller 8 for determining a concentration of the chemical contained in the processing liquid from a relation between a measured thickness of the processing liquid and the processing time. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a substrate processing apparatus and a processing method for processing with a processing liquid while rotating the substrate.

  When a substrate such as a semiconductor wafer or a glass substrate of a liquid crystal display panel is treated with a treatment liquid, the treatment liquid is, for example, an organic solvent chemical such as ethanol, isopropyl alcohol, or hydrofluoric acid. A treatment solution diluted to a concentration may be used.

  When processing a substrate with such a processing solution, the concentration of the chemical solution forming the processing solution may affect the processing accuracy of the substrate. For example, if the concentration of the chemical solution in the processing liquid decreases, the substrate may not be cleaned to a desired cleanliness level. Conversely, if the concentration of the chemical solution increases, the processing on the substrate proceeds excessively and becomes fine. In some cases, the pattern is damaged to cause defective products.

  Conventionally, the various processing liquids described above are sprayed from a nozzle or the like toward a substrate that is rotationally driven in a cup body of a spin processing apparatus, for example, when a chemical liquid and a diluting liquid are mixed at a desired concentration. The substrate is supplied and processed.

  The used processing solution may be discarded, but may be collected and used repeatedly. If the processing liquid is collected and used repeatedly, there is an advantage that the running cost for processing the substrate can be reduced when the processing liquid is expensive.

  For example, Patent Document 1 discloses a substrate processing apparatus that repeatedly uses a processing solution.

JP 2003-297801 A

  By the way, when the treatment liquid is used repeatedly, the concentration of the chemical liquid contained in the treatment liquid, that is, the treatment liquid concentration changes over time due to various causes such as a decrease in the chemical liquid contained in the treatment liquid and an increase / decrease in the dilution liquid. Inevitable.

  However, conventionally, when processing a substrate with a processing liquid, it has not been performed to measure the chemical concentration in the processing liquid supplied to the substrate. For this reason, there is a possibility that the substrate may be processed with a processing solution having a concentration different from the initial concentration, and the substrate may not be cleaned with a desired cleaning accuracy, or the substrate may be damaged.

  In the present invention, when the substrate is processed with the processing liquid, the concentration of the processing liquid can be known so that the substrate can be processed with the processing liquid having a desired concentration. To provide a processing apparatus and a processing method.

This invention is a substrate processing apparatus for processing a substrate with a processing liquid obtained by diluting a chemical with a diluent,
Measuring means for measuring the thickness of the processing solution supplied to the substrate;
A substrate processing apparatus comprising: determination means for determining the concentration of the chemical contained in the processing liquid from the relationship between the thickness of the processing liquid measured by the measuring means and the processing time.

  It is preferable that the determination means obtains the concentration of the chemical solution based on the relationship between the thickness of the processing solution measured in advance and the concentration of the chemical solution.

A chemical supply section for supplying the chemical liquid;
A diluent supply section for supplying the diluent,
Based on the determination of the determination means, the chemical concentration of the treatment liquid is set by controlling the supply amount of at least one of the chemical liquid supplied from the chemical liquid supply unit and the dilution liquid supplied from the dilution liquid supply unit. And a concentration setting means.

The measuring means is
Detecting means for detecting a color gradation change of interference fringes generated by the processing liquid remaining on the substrate;
2. A calculating means for calculating the thickness of the processing solution on the substrate from the color gradation change detected by the detecting means using a light diffraction formula (2nd cos θ = mλ). The substrate processing apparatus as described.

(In the above formula, n is the refractive index of the treatment liquid, d is the thickness of the liquid film, θ is the incident angle of light to the treatment liquid, m is an integer, and λ is the wavelength of light.)
The present invention is a substrate processing method for processing a substrate with a processing solution obtained by diluting a chemical solution with a diluent,
Supplying a treatment liquid to the substrate;
Measuring the thickness of the processing solution supplied to the substrate;
And a step of determining the concentration of the chemical contained in the treatment liquid from the relationship between the measured thickness of the treatment liquid and the treatment time.

  If the concentration of the chemical liquid is determined, it is preferable to include a step of setting the concentration of the chemical liquid in the processing liquid based on the determination.

  According to the present invention, the thickness of the processing liquid supplied to the substrate is measured, and the concentration of the chemical liquid contained in the processing liquid can be determined from the relationship between the thickness and the processing time.

  Therefore, it is possible to know whether or not the concentration of the processing liquid for processing the substrate is appropriate.

1 is a side sectional view showing a schematic configuration of a spin processing apparatus according to a first embodiment of the present invention. The flowchart explaining the calculation procedure of the liquid film thickness on the board | substrate by a processing apparatus. The figure which shows the relationship between the color gradation change of the light of each wavelength of red, green, and blue which the imaging camera measured, and the processing time of a board | substrate. The figure which shows the relationship between a liquid film thickness and the theoretical waveform of the color gradation change of the light of each wavelength of red, green, and blue. The figure which shows the relationship between the liquid film thickness calculated | required from FIG. 3, FIG. 4, and [Table 1], and the process time of a board | substrate. The graph which shows the relationship between the processing time when processing a board | substrate using the processing liquid from which chemical | medical solution density | concentration differs, and the liquid film thickness on a board | substrate. The block diagram which shows the internal structure of a control apparatus. The sectional side view which shows schematic structure of the spin processing apparatus which measures a liquid film thickness together with the laser displacement meter which shows 2nd Embodiment of this invention. A graph of the relationship between the liquid film thickness measured up to several μm measured by a laser displacement meter and the processing time of the substrate, and a liquid film obtained by assuming a plurality of m values in order to obtain a liquid film thickness of a thickness less than that The figure which shows the some graph which shows the relationship between thickness and the process time of a board | substrate. The figure which shows the relationship between the liquid amount (mass) which remains on the board | substrate which shows the 3rd Embodiment of this invention, and the processing time of a board | substrate. The sectional side view which shows schematic structure of the spin processing apparatus which shows 4th Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
1 to 7 show a first embodiment of the present invention. FIG. 1 shows a spin processing apparatus 1 as a processing apparatus for processing a substrate W with a processing liquid L. FIG. The spin processing apparatus 1 includes a cup body 2. A rotating table 3 is provided in the cup body 2. The rotary table 3 is rotated by a drive source 4.

  A substrate W is supplied and held on the upper surface of the rotary table 3, and the processing liquid L is jetted and supplied to the substrate W by the nozzle body 5.

  Above the substrate W, from a fixed imaging device as a detecting means for detecting a color change of interference fringes on the upper surface of the substrate W caused by the processing liquid L remaining on the upper surface of the substrate W processed by the processing liquid L. The color type imaging camera 7 is arranged so that the optical axis O is vertical and coincides with the rotation center of the substrate W.

  The imaging camera 7 is set at a height H so that the entire top surface of the substrate W is within the field of view. Thereby, the imaging camera 7 can detect the change in the color tone of the interference fringe at any position on the substrate W.

  The imaging signal of the imaging camera 7 is output to the control device 8 as calculation control means, and the analog signal is converted into a digital signal. The control device 8 first sets an arbitrary measurement position indicated by A in FIG. 1 on the substrate W as a calculation point based on the converted digital signal, and an axis of light incident on the imaging camera 7 from the measurement position A An angle θ formed by O1 and the optical axis O of the imaging camera 7 is determined from the imaging signal.

  That is, the angle θ can be obtained from the height H from the upper surface of the substrate W to the light receiving surface of the imaging camera 7 and the distance D from the optical axis O of the imaging camera 7 to the measurement position A. The height H is known, and the distance D can be obtained from the imaging signal of the imaging camera 7. Therefore, the control device 8 can calculate the angle θ from these data.

  When the processing of the substrate W by the processing liquid L is completed and the supply of the processing liquid L to the substrate W is stopped, the control device that receives the imaging signal from the imaging camera 7 while the substrate W is rotating. Reference numeral 8 denotes a plurality of wavelengths of light at an arbitrary measurement position A on the substrate W as shown in FIG. 3, that is, interference of red (R), green (G), and blue (B) by a built-in arithmetic processing unit (not shown). The change in the color tone of the stripe is measured and the result is stored. In FIG. 3, a graph X indicates a relationship between color gradation change and time of red (R), Y is green (G), and Z is blue (B). In the figure, time 0 is when supply of the processing liquid L to the substrate W is stopped.

  In FIG. 3, the change in the color tone of the interference fringes at an arbitrary measurement position A is measured, but the change in the color tone of the interference fringes at a plurality of locations along the radial direction of the substrate W can be continuously measured. For example, if the change in the color tone of the interference fringes over the entire length in the radial direction of the substrate W can be measured, the change in the color tone of the interference fringes on the entire surface of the substrate W can be measured because the substrate W is rotating.

  Based on the flowchart shown in FIG. 2, the control device 8 measures changes in the wavelengths of a plurality of light and interference fringes, and at the same time uses red (R), green (G), The liquid film thickness for an arbitrary m value at each wavelength of blue (B) is calculated, and the calculation result is stored.

The above optical diffraction equation is
2nd cos θ = mλ (1) In the above formula (1), n is the refractive index of the processing liquid, d is the thickness of the liquid film, θ is the incident angle of light to the processing liquid, m is an integer, and λ is the wavelength of light.

The following [Table 1] shows the liquid at each m value when m values are sequentially changed from 0 to 10 at intervals of 0.5 with respect to the wavelengths of red (R), green (G), and blue (B). The calculation result of the film thickness is shown. That is, in the above equation (1), the refractive index n, the angle θ, and the wavelength λ are known. Therefore, if the m value is set from 0 to 10 at intervals of 0.5, the wavelength λ of each light for each m value. The thickness of the liquid film of the treatment liquid L measured every time can be calculated.

  FIG. 4 shows waveforms of theoretical color gradations with respect to the liquid film thickness of light of each wavelength of red (R), green (G), and blue (B) created based on the calculation results of [Table 1]. From this theoretical color gradation waveform, the m value that matches the peak value of the light of each wavelength is determined. In FIG. 4, the lower limit peak values of light of red (R), green (G), and blue (B) wavelengths match at the position where the liquid film thickness is 0. Therefore, the m value at the position where the liquid film thickness is 0 is 0. In other words, it means that the processing liquid L on the substrate W decreases sequentially until the thickness of the processing liquid L on the rotating substrate W becomes zero.

  Next, the theoretical color gradation waveform of FIG. 4 is compared with the actually measured gradation change of the color of each wavelength at the time of FIG. 3. In FIG. 3, the liquid film thickness of FIG. The time for obtaining the closest state to the state where the lower limit peaks of the light of each wavelength of R, G, and B at the 0 position coincide is obtained. In FIG. 3, it is determined that the state of the waveform of light of each wavelength of R, G, B is closest to the waveform when the liquid film thickness is 0 in FIG.

  Therefore, in the measured waveform in FIG. 3, the m value at time 50 sec is zero. If it is found that the m value of the last lower limit peak at time 50 sec of the actually measured waveform in FIG. 3 is 0, for example, the m value in the actually measured waveform of wavelength red (R) is one of the last lower limit peaks. Since the m value of the previous lower limit peak is 1, the previous value is 2,..., The time when the m value is 0, 1, 2, 3,.

  Furthermore, since the relationship between the m value at the wavelength red (R) and the liquid film can be obtained from [Table 1], the supply of the processing liquid L is stopped as shown in FIG. 3 and [Table 1] to FIG. Then, the relationship between the time and the liquid film on the rotating substrate W can be obtained. Similarly, the relationship between the time and the liquid film from when the supply of the processing liquid L to the substrate W at the wavelengths of green (G) and blue (B) is stopped can be obtained. In the case of green (G) and blue (B), the same result as that obtained when the wavelength red (R) is used is obtained.

  That is, in the drying process after the supply of the processing liquid L onto the rotationally driven substrate W is stopped, the relationship between the processing time and the liquid film thickness at an arbitrary measurement position A of the substrate W set by the control device 8 is shown. The control device 8 can instantaneously calculate the graph shown in FIG.

  Although the control device 8 obtains the relationship between the processing time and the liquid film thickness at an arbitrary measurement position A on the substrate W, if the position set by the control device 8 is set over the entire length of the radius of the substrate W, the substrate W Is rotating, the relationship between the processing time and the liquid film thickness on the entire surface of the substrate W can be obtained.

  If the relationship between the processing time and the liquid film thickness is obtained as described above and the data is taught to the control device 8 in advance, the substrate W is subsequently subjected to the same conditions, that is, the rotation speed, the type of the processing liquid L, and the nozzle. If the injection amount and the injection direction of the processing liquid L from the body 5 are set to be the same, it can be known in advance that the relationship between the liquid film thickness on the substrate W and the processing time becomes the graph shown in FIG. .

  Therefore, it is possible to set, for example, how thin the liquid film is to be finished by the data taught based on the calculation of FIG. In the case of a chemical solution such as a liquid or a stripping solution, the effect of the chemical solution on the substrate after the drying process can be controlled by the amount of the chemical solution remaining on the substrate W. When the processing solution L is a cleaning solution, the substrate W is dried. The state can be controlled.

  Since the measurable thickness of the liquid film at this time is several μm or less as apparent from [Table 1], the thickness that cannot be measured by the conventional measuring method using laser light should be measured. In addition, by using the color gradation change of the interference fringes, there is no restriction on the measurement location. That is, if the entire surface of the substrate W can be imaged by the imaging camera 7, the change in the liquid film thickness on the entire surface can be measured simultaneously.

  The nozzle body 5 is configured to eject two types of mixed liquids, and the treatment liquid L supplied to the nozzle body 5 is obtained by setting a chemical solution to a predetermined concentration with a diluent. That is, a mixer 9 is connected to the nozzle body 5 via a temperature control unit 9a. A chemical solution supply unit 10 and a diluent supply unit 11 are connected to the mixer 9 by pipes 10a and 11a, respectively.

  The pipe 10a is provided with a first flow control valve 12, and the pipe 11a is provided with a second flow control valve 13.

The flow rate control valves 12 and 13 each have an opening degree according to a control signal from an output unit 8e (shown in FIG. 7) provided in the control device 8, that is, supply amounts of a chemical solution and a diluent to the mixer 9 described later. To be controlled. Thereby, the concentration of the chemical liquid contained in the processing liquid L supplied to the nozzle body 5, that is, the concentration of the processing liquid L is set.
The temperature control unit 9a is configured to keep the temperature of the processing liquid L supplied to the nozzle body 5 constant.

  The processing liquid L is for cleaning the substrate W. For example, isopropyl alcohol is used as the chemical liquid and pure water is used as the diluting liquid. The chemical liquid used as the treatment liquid L may be ozone water, hydrofluoric acid, ammonia hydrogen peroxide water, or the like. When these chemical liquids are used, a diluting liquid suitable for diluting the chemical liquid is used. It is done.

  FIG. 6 is a graph in which the relationship between the processing time and the thickness of the liquid film on the substrate W is measured by experiments when the substrate W is processed with the processing liquid L using isopropyl alcohol as the chemical liquid and pure water as the diluent. It is. In the figure, the curve S1 has a chemical concentration of 100%, the curve S2 is 80%, S3 is 40%, S4 is 10%, and S5 is 0%.

  As can be seen from FIG. 6, when the concentration of isopropyl alcohol, which is a chemical solution contained in the processing liquid L, is different, how the thickness of the liquid film of the processing liquid L on the substrate W changes as the processing time elapses. Were confirmed to be different. That is, the shapes of the curves S1 to S5 are different.

  Therefore, if the processing liquid L is supplied to the substrate W and the processing is started, the thickness of the liquid film of the processing liquid L on the substrate W is measured, and the shape of the change state is shown in FIG. Compared with the curves S1 to S5, the concentration of the chemical liquid contained in the processing liquid L at that time can be known.

  As shown in FIG. 7, the control device 8 is provided with a storage unit 8a. In this storage unit 8a, the relationship between the processing time and the change in the thickness of the liquid film for each processing liquid L having different concentrations, in this embodiment, data of the shapes of the curves S1 to S5 shown in FIG. 6 is stored in advance. . Then, when the processing liquid L is supplied to the substrate W and the processing is started, the arithmetic processing unit 8b of the control device 8 determines the thickness of the processing liquid L on the substrate W with respect to the processing time based on the imaging of the imaging camera 7. Are sequentially calculated.

  Thus, the curves obtained from the relationship between the processing time and the thickness of the liquid film of the processing liquid L are curves S1 to S5 stored in advance in the storage unit 8a by the comparison unit 8c provided in the control device 8. Compared with Accordingly, the concentration of the processing liquid L that is processing the substrate W can be known. While being clogged and processing the substrate W with the processing liquid L, the concentration of the chemical liquid contained in the processing liquid L used at that time can be known.

  When the concentration of the processing liquid L that is processing the substrate W is obtained, the determination unit 8d provided in the control device 8 determines whether or not the concentration of the processing liquid L is a preset optimum concentration. Is done. As a result of determination by the determination unit 8d, when the concentration of the chemical liquid contained in the processing liquid L has decreased, the first flow rate control valve 12 is driven in the opening direction from the output unit 8e of the control device 8 described above. A control signal is output.

  As a result, the amount of the chemical liquid supplied from the chemical liquid supply unit 10 to the mixer 9 increases, so that the concentration of the chemical liquid contained in the processing liquid L increases, and the concentration can be set to a preset concentration.

  In this case, instead of the first flow rate control valve 12, the second flow rate control valve 13 is operated in the closing direction to decrease the supply amount of the diluent and increase the chemical concentration of the processing liquid L. May be. Furthermore, the chemical concentration of the processing liquid L may be set by controlling the opening degree of both the first and second flow control valves 10a and 11a.

  Conversely, when the chemical concentration of the processing liquid L is high, a control signal for driving the first flow control valve 12 in the closing direction is output from the control device 8. As a result, the amount of the chemical liquid supplied from the chemical liquid supply unit 10 to the mixer 9 is reduced, so that the chemical concentration of the processing liquid L is lowered, and the concentration can be set to a preset concentration.

  In this case, the second flow rate control valve 13 may be actuated in the opening direction to increase the supply amount of the diluting liquid to decrease the chemical concentration of the processing liquid L. You may set the chemical | medical solution density | concentration of the process liquid L by controlling the opening degree of both the 2 flow control valves 10a and 11a.

  That is, the chemical solution supply unit 10, the diluent supply unit 11, and the first and second flow rate control valves 12 and 13 constitute a concentration setting unit that sets the chemical concentration of the processing liquid L.

  In this way, while the substrate is being processed with the processing liquid L, the chemical concentration of the processing liquid L is obtained, and if the chemical concentration is deviated from a preset value, the concentration is adjusted to the set concentration. Can do. Therefore, since the substrate W can be processed with the processing liquid L having the chemical concentration most suitable for the cleaning process, for example, the processing of the substrate W is reliably and quickly performed with the processing liquid L having an excessively high chemical concentration. Can be prevented from being damaged.

  FIG. 8 and FIG. 9 show a second embodiment of the present invention showing a modification for measuring the film thickness of the treatment liquid L. FIG. In this embodiment, the laser displacement meter 15 and the imaging camera 7 as the detection means are used together to obtain the relationship between the time after the supply of the processing liquid L is stopped and the thickness of the liquid film.

  That is, when the laser displacement meter 15 detects the first laser beam B1 emitted from the laser displacement meter 15 and reflected by the upper surface of the substrate W and the second laser beam B2 reflected by the liquid surface, the laser displacement meter 15 detects up to several μm. The thickness of the liquid film is measured, and a thickness less than that is obtained by a color gradation change due to interference fringes.

  The laser displacement meter 15 is installed side by side with the imaging camera 7 above the substrate W held on the turntable 3 as shown in FIG. After stopping the supply of the processing liquid L to the substrate W, a signal based on the substrate W detected by the laser displacement meter 15 and the laser beams B1 and B2 reflected from the liquid surface is output to the control device 8 and processed. Thereby, the control device 8 detects the relationship between the time at an arbitrary measurement position A on the substrate W and the thickness of the liquid film up to a thickness of several μm as shown by a graph G0 in FIG.

  Then, since it is difficult to measure a film thickness thinner than that with the laser displacement meter 15, measurement is performed using the imaging camera 7.

  That is, in parallel with the measurement by the laser displacement meter 15, the control device 8 detects the color gradation change of the interference fringes at the measurement position A on the substrate W after the supply of the processing liquid L is stopped by the imaging signal from the imaging camera 7. To do. The detection result is as shown in FIG. 3 as in the first embodiment.

  At the same time, the control device 8 changes red (R), green (G), blue when the m value is changed from 0 to 10 at intervals of 0.5 based on the equation of light diffraction shown as equation (1). The liquid film thickness at the wavelength of (B) is calculated and stored. The calculation table at this time is [Table 1].

  Next, the control device 8 assumes that the m value of the lower limit peak of the measurement wavelength at the time of 50 sec in FIG. 3 is 0, 6, or 12, and shows a graph of the relationship between the time and the liquid film thickness at that time. Based on [Table 1] and FIG. 3, it is created by the same method as in the first embodiment. The graph of each m value is shown by G1-G3 in FIG. In FIG. 8, graph G1 is when m value is 0, G2 is when m value is 6, and G3 is when m value is 12.

  Thus, if the graphs G1 to G3 indicating the relationship between time and the liquid film thickness are obtained, the graph G1 obtained by the laser displacement meter 15 out of the graphs G1 to G3, that is, fitting with the graph G0. The control device 8 selects a graph to be selected from G1 to G3 by the following method.

  That is, in the graph G3 in which the m value is 12, the liquid film thickness at the start of measurement is thicker than the final liquid film thickness of the graph G0 obtained by the laser displacement meter 15. That is, since the liquid film thickness does not increase as the measurement time elapses, it is determined that the graph G3 with an m value of 12 does not match the graph G0.

  Similarly to the graph G3, the graph G2 having an m value of 6 is also thicker than the final liquid thickness of the graph G0 obtained by the laser displacement meter 15 at the start of measurement. Therefore, it is determined that the graph G3 is not compatible with the graph G0.

  Compared to these graphs G3 and G2, the graph G1 is compatible with the graph G0 because the liquid film thickness at the start of measurement is thinner than the final liquid film thickness of the graph G0 obtained by the laser displacement meter 15. It is determined.

  Therefore, since the m value at the last lower limit peak of the actually measured waveform in FIG. 3 can be determined to be 0, the relationship between the processing time on the substrate W and the liquid film thickness based on the determination is a graph that fits the graph G0. This is indicated by G1. That is, a graph that matches the extension destination of the graph G0 obtained by the laser displacement meter 15 may be selected.

  In other words, if the thickness of the liquid film is measured to a thickness of several μm by the laser displacement meter 15, the thickness of the liquid film on the substrate W below that is shown by the graph G1 shown in FIG. Can be obtained as

  Therefore, if the data of the graph G1 is taught to the control device 8, then when the substrate W is processed under the same conditions, the relationship between the time and the thickness of the liquid film shown in the graph G1 in FIG. 9 is applied. Thus, the thickness of the liquid film on the substrate W can be controlled.

  In the second embodiment, the laser displacement meter 15 is provided above the substrate W so as to be driven along the radial direction of the substrate W, and the thickness of the liquid film at an arbitrary position in the radial direction of the substrate W is set. It may be possible to measure.

  FIG. 10 shows a third embodiment of the present invention. In this embodiment, after the supply of the processing liquid L to the substrate W is stopped, the mass of the substrate W is measured to determine the m value in the optical diffraction equation.

  That is, FIG. 10 is a diagram showing a graph measured for each time with the amount of liquid [mg] remaining on the substrate W after the supply of the processing liquid L to the substrate W stopped as a mass. If the liquid amount can be obtained, the film thickness of the processing liquid L on the upper surface of the substrate W can be calculated from [Table 1] from the relationship between the liquid amount and the area of the substrate W. That is, the relationship between an arbitrary m value and the liquid amount can be obtained from [Table 1] and FIG.

  Therefore, the liquid amount (liquid film thickness) when the m value is 0 to 4 at the time of 20 sec and 30 sec is obtained from [Table 1]. In FIG. 9, the white circle has an m value of 0, the black rhombus has an m value of 1, the black square has an m value of 2, the black triangle has an m value of 3, and the black circle has an m value of 4.

  As a result, since a black rhombus having an m value of 1 is positioned on the graph at 20 sec, it can be determined that the m value of the graph is 1. That is, in the graph of FIG. 3, the m value of the last lower limit peak is 1. As can be seen from [Table 1], for example, in the case of measurement using the wavelength of red (R), the final liquid film thickness on the substrate W is not 23, but 237.3174 nm. This means that the film disappears from the substrate.

  Therefore, if the m value is obtained in this way, a graph showing the relationship between the processing time and the liquid film thickness as shown in FIG. 5 can be obtained based on [Table 1] and FIG. The liquid film thickness during the processing of the substrate W can be controlled by the graph as in the first and second embodiments.

  FIG. 11 shows a fourth embodiment which is a modification of the first embodiment of the present invention. In this embodiment, a half mirror 21 is disposed between the imaging camera 7 and the substrate W held on the turntable 3. As a result, it is possible to prevent the imaging camera 7 from appearing in the processing liquid L remaining on the plate surface of the substrate W, so that the imaging of the substrate W by the imaging camera 7 can be performed with high accuracy.

The half mirror 21 is sized so as to cover the entire surface of the substrate W, but may be sized so long as at least the shadow of the imaging camera 7 is not reflected on the substrate W.
Needless to say, the fourth embodiment can be applied to the second and third embodiments.

  In each of the above embodiments, the imaging camera 7 is arranged above the substrate W with the optical axis perpendicular, but the optical axis of the imaging camera 7 is inclined at an angle θ, for example, 45 degrees. It may be. If the imaging camera 7 is arranged with its optical axis inclined, the measurement range by the imaging camera 7 can be (1 / cos θ) times. That is, the measurement accuracy by the imaging camera 7 can be increased.

  When the imaging camera 7 is arranged with its optical axis inclined at an angle of, for example, 45 degrees, a light source that irradiates the plate surface of the substrate W symmetrically with the imaging camera 7 about the vertical axis may be arranged. Good.

  In this way, as in the fourth embodiment, the measurement range by the imaging camera 7 can be increased by (1 / cos θ), and the imaging region by the imaging camera 7 is illuminated. Further, the measurement accuracy can be further improved.

  When the substrate is illuminated with a light source, it is preferable that light reaching the substrate is only light from the light source. For this purpose, for example, the cup body is formed of an opaque material that blocks external light so that external light does not enter the cup body provided with the turntable on which the substrate W is placed, What is necessary is just to cover the circumference | surroundings with a light-shielding member so that external light may not enter into this cup body. By doing so, it is possible to measure the thickness of the liquid film on the substrate with high accuracy.

  Further, although the case where the substrate is processed by the spin processing apparatus has been described as an example, the present invention can be applied even when the substrate is horizontally transported by the transport roller.

  Further, in each of the above-described embodiments, the chemical liquid and the dilution liquid of the processing liquid to be supplied to the nozzle body may be heated and supplied to a predetermined temperature by heating means such as a heater.

  DESCRIPTION OF SYMBOLS 2 ... Cup body, 3 ... Rotary table, 5 ... Nozzle body, 7 ... Imaging camera (detection means), 8 ... Processing apparatus (calculation control means), 21 ... Half camera.

Claims (6)

A substrate processing apparatus for processing a substrate with a processing solution obtained by diluting a chemical solution with a diluent,
Measuring means for measuring the thickness of the processing solution supplied to the substrate;
A substrate processing apparatus comprising: determination means for determining the concentration of the chemical contained in the processing liquid from the relationship between the thickness of the processing liquid measured by the measuring means and the processing time.   The substrate processing apparatus according to claim 1, wherein the determination unit obtains the concentration of the chemical solution based on a relationship between the thickness of the processing solution measured in advance and the concentration of the chemical solution. A chemical supply section for supplying the chemical liquid;
A diluent supply section for supplying the diluent,
Based on the determination of the determination means, the chemical concentration of the treatment liquid is set by controlling the supply amount of at least one of the chemical liquid supplied from the chemical liquid supply unit and the dilution liquid supplied from the dilution liquid supply unit. The substrate processing apparatus according to claim 1, further comprising: a concentration setting unit. The measuring means is
Detecting means for detecting a color gradation change of interference fringes generated by the processing liquid remaining on the substrate;
2. A calculating means for calculating the thickness of the processing solution on the substrate from the color gradation change detected by the detecting means using a light diffraction formula (2nd cos θ = mλ). The substrate processing apparatus as described.
(In the above formula, n is the refractive index of the treatment liquid, d is the thickness of the liquid film, θ is the incident angle of light to the treatment liquid, m is an integer, and λ is the wavelength of light.) A substrate processing method of processing a substrate with a processing solution obtained by diluting a chemical solution with a diluent,
Supplying a processing solution to the substrate;
Measuring the thickness of the processing liquid supplied to the substrate;
And a step of determining the concentration of the chemical contained in the treatment liquid from the relationship between the measured thickness of the treatment liquid and the treatment time.   6. The substrate processing method according to claim 5, further comprising a step of setting the concentration of the chemical in the processing liquid based on the determination when the concentration of the chemical is determined.

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