JP2010010242A - Substrate processing method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate processing method and apparatus, which sufficiently processes a substrate surface while a usage of chemical is suppressed. <P>SOLUTION: In initial chemical processing, a silicon oxide film is formed on the substrate surface Wf, and the substrate surface Wf is a hydrophilic face. In this initial chemical processing (time until time T1 elapses from time 0), a flow rate of hydrofluoric acid solution is suppressed to 510 (mL/min) and the usage of hydrofluoric acid is suppressed. Since the flow rate of hydrofluoric acid solution is increased to 1,530 (mL/min) and continuous chemical processing is performed at timing when at least part of a silicon layer of the substrate W is exposed by the initial chemical processing, the hydrofluoric acid solution covers the whole substrate surface Wf and etching removal of the silicon oxide film can be continued even if the silicon layer is exposed to part of the substrate surface Wf and a hydrophobic face is formed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a substrate processing method and a substrate processing apparatus for supplying a chemical solution to a surface of a substrate to perform chemical treatment on the substrate. The substrates to be processed include semiconductor wafers, glass substrates for photomasks, glass substrates for liquid crystal displays, glass substrates for plasma displays, FED (Field Emission Display) substrates, optical disk substrates, and magnetic disks. And a magneto-optical disk substrate.

  The manufacturing process of an electronic component such as a semiconductor device or a liquid crystal display device includes a step of repeatedly forming a fine pattern by repeatedly performing processes such as film formation and etching on the surface of the substrate. Here, in order to perform fine processing well, it is necessary to keep the substrate surface clean. Therefore, a substrate cleaning process using a chemical solution is performed as necessary. For example, in the substrate processing technique described in Patent Document 1, after a substrate such as a semiconductor wafer is held almost horizontally on a spin chuck, the spin chuck is rotated and diluted with hydrofluoric acid on the surface of the substrate held by the spin chuck. A chemical solution such as a solution is supplied to remove foreign substances on the substrate surface. That is, when the substrate is a silicon wafer, since the silicon oxide film on the surface is a hydrophilic surface, the chemical solution spreads outward in the radial direction of the substrate by centrifugal force, and a continuous liquid film is formed on the entire surface of the substrate, thereby The silicon oxide film which is the uppermost layer on the surface is removed by etching (chemical solution treatment). Thereafter, the supply of the chemical solution is stopped, and a rinse solution such as pure water or DIW (deionized water) is supplied to the substrate surface, so that the chemical solution on the substrate surface is washed away (rinse process).

  Patent Document 2 describes an etching method for performing an etching process on a substrate. In this etching method, a substrate such as a semiconductor wafer is horizontally placed on the upper end of a rotating system and rotated at a high speed, and an etching solution (chemical solution) is dropped on the surface of the rotating substrate one by one and etched. The rinsing liquid is sprayed to wash away the etching liquid.

  Further, Patent Document 3 discloses a wet etching method in which a hydrophilic film is removed from a substrate by rotating the substrate while spraying a chemical solution such as an etching aqueous solution on a substrate having a hydrophilic film deposited on a water repellent material. Are listed.

JP 2004-319990 A (FIGS. 4 and 13) JP-A-8-279484 (paragraphs 0020, 0021) JP 2002-151462 A

  By the way, when the chemical solution is supplied to the substrate surface as described above to perform the chemical treatment, it is important to form a liquid film of the chemical solution over the entire substrate surface. Therefore, when the substrate surface is hydrophobic, it is necessary to increase the flow rate of the chemical solution supplied to the substrate surface compared to when the substrate surface is hydrophilic. Also, when the substrate surface changes from hydrophilic to hydrophobic during the chemical treatment, the chemical flow rate is set to a flow rate suitable for the hydrophobic surface from the start of the chemical treatment, that is, a relatively large flow rate. For example, as described in Patent Document 1, when a chemical treatment is performed on a silicon substrate, a silicon oxide film is formed on the substrate surface at the initial stage of the chemical treatment, and thus the substrate surface is a hydrophilic surface. However, when the silicon oxide film is etched away by the chemical treatment and the silicon substrate surface is exposed, it becomes a hydrophobic surface. Further, as described in Patent Document 3, the hydrophilic film formed on the water repellent material is removed by etching, so that the water repellent material is exposed and the substrate surface becomes a hydrophobic surface. Thus, when the hydrophobic state of the substrate surface changes during the chemical treatment, even if the substrate surface becomes a hydrophobic surface, the chemical solution supplied to the substrate surface to the extent that it is possible to cover the entire substrate surface with the chemical solution The flow rate of was increased.

  As described above, the chemical solution used for the chemical treatment is often disposable, and suppressing the consumption of the chemical solution is one of important technical problems. However, conventionally, even when the hydrophobic state changes during the chemical treatment as described above, the chemical flow rate is fixed at a relatively high flow rate from the start of the chemical treatment, and this is the reason for the substrate processing running. It was one of the main factors that increased costs.

  This invention is made | formed in view of the said subject, and it aims at providing the substrate processing method and substrate processing apparatus which can process a substrate surface favorably, suppressing the usage-amount of a chemical | medical solution.

  The present invention provides a substrate processing method and a substrate processing apparatus for supplying a chemical solution to the surface of a substrate to perform chemical treatment on the substrate. The substrate processing method is configured as follows to achieve the above object. That is, the substrate processing method according to the present invention is characterized in that the flow rate of the chemical liquid supplied to the substrate surface is controlled according to the hydrophobic state of the substrate surface during the chemical liquid processing. In addition, the substrate processing apparatus according to the present invention includes a nozzle that discharges the chemical toward the substrate surface, a liquid supply unit that supplies the chemical to the nozzle while adjusting the flow rate of the chemical, and a hydrophobic state of the substrate surface during the chemical processing And a control means for controlling the flow rate of the chemical liquid supplied to the substrate surface by controlling the liquid supply unit according to the above.

  In the invention (substrate processing method and substrate processing apparatus) configured as described above, the chemical liquid is supplied to the surface of the substrate and the chemical liquid processing is performed on the substrate. The situation can change. Therefore, in the present invention, the flow rate of the chemical solution supplied to the substrate surface is controlled according to the hydrophobic state. Therefore, even if the hydrophobic state changes during the chemical processing, the chemical processing is executed at a chemical flow rate corresponding to the hydrophobic state.

  Here, the hydrophobic state of the substrate surface may be determined as follows, and the hydrophobic state of the substrate surface can be accurately obtained by using these determination methods. In other words, the chemical treatment is started by supplying the chemical solution to the substrate surface, and the chemical treatment proceeds with time, and the hydrophobic state of the substrate surface also changes. Therefore, the hydrophobic state of the substrate surface can be determined based on the elapsed time from the start of supply of the chemical solution. As another determination method, a method of determining the hydrophobic state of the substrate surface based on an image obtained by imaging the substrate surface may be used, and the hydrophobic state of the substrate surface can be determined directly and in real time. In particular, even if the substrate surface is imaged continuously or intermittently during chemical processing to obtain images, and the hydrophobic status is judged based on image information indicating the substrate surface obtained by applying image processing to each image. In this case, the hydrophobic state of the substrate surface that changes every moment can be judged in real time.

  In the present invention, the chemical flow rate is controlled during the chemical treatment, but the concentration may be controlled so that the chemical concentration during the chemical treatment is constant, thereby causing uneven concentration of the chemical during the chemical treatment. Generation | occurrence | production can be prevented and, as a result, the uniformity of the chemical | medical solution process within a substrate surface can be improved.

  According to the present invention, since the flow rate of the chemical solution supplied to the substrate surface is controlled by controlling the liquid supply unit according to the hydrophobic state of the substrate surface during the chemical treatment, the substrate surface while suppressing the amount of the chemical solution used. Can be processed satisfactorily.

<First Embodiment>
FIG. 1 is a diagram showing a first embodiment of a substrate processing apparatus according to the present invention. FIG. 2 is a block diagram showing an electrical configuration of the apparatus shown in FIG. This substrate processing apparatus is a single-wafer type substrate processing apparatus used for a cleaning process for removing unnecessary substances such as an oxide film adhering to a surface Wf of a substrate W such as a silicon wafer. More specifically, the apparatus is a device that spin-drys the substrate surface Wf after the substrate surface Wf is subjected to a chemical solution treatment with a chemical solution such as a hydrofluoric acid solution or a rinse treatment with a rinse solution such as pure water or DIW.

  The substrate processing apparatus includes a spin chuck 2 that rotates while holding the substrate W in a substantially horizontal position with the substrate surface Wf facing upward, and a chemical solution or the like toward the surface Wf of the substrate W held by the spin chuck 2. And a nozzle 4 for discharging a rinsing liquid.

  The spin chuck 2 has a rotation support shaft 6 connected to a rotation shaft of a chuck rotation mechanism 8 including a motor, and can rotate around a rotation axis J (vertical axis) by driving the chuck rotation mechanism 8. The rotating spindle 6 and the chuck rotating mechanism 8 are accommodated in a cylindrical casing 10. Further, a disc-shaped spin base 12 is integrally connected to the upper end portion of the rotation support shaft 6 by a fastening component such as a screw. Therefore, the spin base 12 rotates about the rotation axis J by driving the chuck rotation mechanism 8 in accordance with an operation command from the control unit 14 that controls the entire apparatus. The control unit 14 also controls the chuck rotation mechanism 8 to adjust the rotation speed of the spin base 12.

  Near the periphery of the spin base 12, a plurality of chuck pins 16 for holding the periphery of the substrate W are provided upright. Three or more chuck pins 16 may be provided in order to securely hold the circular substrate W, and are arranged at equiangular intervals along the peripheral edge of the spin base 12. Each of the chuck pins 16 includes a substrate support portion that supports the peripheral portion of the substrate W from below, and a substrate holding portion that holds the substrate W by pressing the outer peripheral end surface of the substrate W supported by the substrate support portion. Yes. Each chuck pin 16 is configured to be switchable between a pressing state in which the substrate holding portion presses the outer peripheral end surface of the substrate W and a released state in which the substrate holding portion is separated from the outer peripheral end surface of the substrate W.

  When the substrate W is delivered to the spin base 12, the plurality of chuck pins 16 are released, and when the substrate processing described later is performed on the substrate W, the plurality of chuck pins 16 are pressed. State. By setting the pressing state in this way, the plurality of chuck pins 16 can grip the peripheral edge of the substrate W and hold the substrate W in a substantially horizontal posture at a predetermined interval from the spin base 12. As a result, the substrate W is supported with its front surface Wf facing upward and the back surface Wb facing downward. The substrate holding means is not limited to the chuck pins 16, and a vacuum chuck that sucks the substrate back surface Wb and supports the substrate W may be used.

  The nozzle 4 is connected to the liquid supply unit 20 via the valve 18. The liquid supply unit 20 selectively supplies the chemical liquid and the rinse liquid to the nozzle 4 and can adjust the flow rate and concentration of each liquid. That is, the liquid supply unit 20 has a mixing valve 22, and a hydrofluoric acid supply system and a DIW supply system are connected to the mixing valve 22.

  Among these supply systems, the hydrofluoric acid supply system includes a hydrofluoric acid supply source 24, a pipe 26 connecting the hydrofluoric acid supply source 24 and the mixing valve 22, and a hydrofluoric acid supplied to the mixing valve 22 through the pipe 26. And a flow rate controller 28 for controlling the flow rate of the acid. The flow rate controller 28 includes a flow rate adjustment valve (electrically operated valve) 30, a flow meter 32, and a flow rate control unit (not shown). The flow rate control unit detects and calculates a flow rate signal measured by the flow meter 32. Then, the flow rate adjusting valve 30 is controlled so that the flow rate of hydrofluoric acid fed to the mixing valve 22 becomes the set flow rate given from the control unit 14.

  The DIW supply system is configured in the same manner as the hydrofluoric acid supply system. That is, the DIW supply system includes a pipe 36 that connects the DIW supply source 34 and the mixing valve 22, and a flow rate controller 38 that is inserted into the pipe 36 and controls the flow rate of DIW supplied to the mixing valve 22. The flow rate controller 38 includes a flow rate adjustment valve (electric valve) 40, a flow meter 42, and a flow rate control unit (not shown). The flow rate control unit detects and calculates a flow rate signal measured by the flow meter 42. The flow rate adjustment valve 40 is controlled so that the DIW flow rate fed to the mixing valve 22 becomes the set flow rate given from the control unit 14. Note that the DIW supply source 34 is not an indispensable component of the above apparatus, and DIW supplied from a DIW supply apparatus that is one of the utilities of the factory where the apparatus is installed may be used.

  As described above, in the present embodiment, the liquid supply unit 20 configured as described above controls the hydrofluoric acid flow rate and DIW flow rate fed to the mixing valve 22, thereby hydrofluoric acid in the hydrofluoric acid solution prepared by the mixing valve 22. The hydrofluoric acid solution can be supplied to the nozzle 4 while directly and dynamically adjusting the concentration and the flow rate of the hydrofluoric acid solution. Further, the liquid supply unit 20 controls the DIW flow rate by the flow rate controller 38 in a state in which the supply of hydrofluoric acid to the mixing valve 22 is stopped, thereby adjusting the DIW flow rate directly and dynamically, and using the DIW as a rinse liquid. It is possible to supply to.

  A receiving member 44 is fixedly attached around the casing 10. Three cylindrical partition members are erected on the receiving member 44. And three spaces are formed as a drainage tank by the combination of these partition members and the casing 10. Above these drainage tanks, a splash guard 46 is provided so as to be movable up and down with respect to the rotation axis J of the spin chuck 2 so as to surround the periphery of the substrate W held in a horizontal posture on the spin chuck 2. ing. The splash guard 46 has a shape that is substantially rotationally symmetric with respect to the rotation axis J, and includes three guards arranged concentrically with the spin chuck 2 from the radially inner side toward the outer side. Then, the splash guard 46 is lifted and lowered stepwise by driving a guard lifting mechanism (not shown), so that the hydrofluoric acid solution and the rinsing liquid scattered from the rotating substrate W can be separated and discharged. Yes.

  In the substrate processing apparatus configured as described above, the control unit 14 controls each part of the apparatus according to a program stored in a memory (not shown) to perform a chemical solution process, a rinse process, and a drying process on the substrate W. . Of these, the hydrofluoric acid solution used in the chemical treatment corresponds to the “chemical solution” of the present invention. In this embodiment, the concentration of DIW and hydrofluoric acid is (50: 1) as shown in FIG. Concentrated hydrofluoric acid solution is used as a chemical solution. By executing the initial chemical treatment and the continuous chemical treatment using the hydrofluoric acid solution, the hydrophilic film such as the silicon oxide film is removed from the silicon substrate surface Wf by etching. Hereinafter, the substrate processing by the substrate processing apparatus will be described with reference to FIG.

  The control unit 14 lowers the splash guard 46 so that the spin chuck 2 protrudes from the upper end portion of the splash guard 46. In this state, an unprocessed substrate W is carried into the apparatus by a substrate transport means (not shown). More specifically, the substrate W is carried into the apparatus with the substrate surface Wf facing upward and is held by the spin chuck 2. Following this, the splash guard 46 is raised and chemical processing is started on the substrate W.

  In the process of executing the chemical process (chemical process), the nozzle 4 is moved above the central portion of the substrate surface Wf, and the substrate W held on the spin chuck 2 by driving the chuck rotating mechanism 8 is within the range of 200 to 1200 rpm. Rotate at a rotation speed determined by (for example, 800 rpm). On the other hand, in the liquid supply unit 20, a hydrofluoric acid solution is prepared as a chemical solution. That is, the initial hydrofluoric acid flow rate value for hydrofluoric acid is given from the control unit 14 to the hydrofluoric acid flow rate controller 28, and hydrofluoric acid is supplied to the mixing valve 22 at the initial hydrofluoric acid flow rate value (10 (mL / min) in this embodiment). It is sent. Further, an initial DIW flow rate value for DIW is given from the control unit 14 to the DIW flow rate controller 38, and DIW is sent to the mixing valve 22 at an initial DIW flow rate value (500 (mL / min) in this embodiment). Thus, DIW and hydrofluoric acid are mixed in the mixing valve 22 to prepare a hydrofluoric acid solution having a desired concentration (50: 1) as a chemical solution. Then, by opening the valve 18, a hydrofluoric acid solution having a desired concentration is supplied from the nozzle 4 to the substrate surface Wf at 510 (mL / min). In this initial chemical treatment, since a hydrophilic film such as a silicon oxide film is formed on the substrate surface Wf as described above, the hydrofluoric acid solution supplied to the substrate surface Wf is relatively low in flow rate. First, the substrate surface Wf is spread over the entire substrate surface Wf while covering the substrate surface Wf, and the etching process (chemical solution process) of the substrate surface Wf with hydrofluoric acid is performed as a whole and almost simultaneously to start a uniform etching process.

  By performing this initial chemical treatment, etching removal of the silicon oxide film proceeds, and when a predetermined time T1 has passed from the start of the chemical treatment, most of the silicon oxide film is removed by etching and at least one of the silicon layers of the substrate W is removed. The part is exposed. Since the exposed portion becomes a hydrophobic surface, coverage with the chemical solution becomes difficult when the flow rate of the hydrofluoric acid solution is low. Therefore, in the present embodiment, the time (low flow time) T1 during which at least a part of the silicon layer of the substrate W is exposed by the initial chemical solution processing is stored in advance in a memory (not shown), and the initial chemical solution processing is performed. The hydrophobic state of the substrate surface Wf is determined based on the elapsed time from the start. That is, it is determined that the substrate surface Wf has become a hydrophobic surface when the time T1 has elapsed from the start of the initial chemical treatment, and the flow rate of the hydrofluoric acid solution is increased as shown in FIG. That is, the control unit 14 increases the flow rate of hydrofluoric acid applied to the flow rate controller 28 for hydrofluoric acid to 30 (mL / min)) and feeds hydrofluoric acid to the mixing valve 22 at 30 (mL / min)). 14 increases the DIW flow rate value applied to the DIW flow rate controller 38 to 1500 (mL / min)) and feeds DIW to the mixing valve 22 at 1500 (mL / min)). As a result, the hydrofluoric acid solution is supplied to the substrate surface Wf in a state in which only the flow rate is increased three times as compared with the initial chemical treatment without changing the chemical concentration. For this reason, even if a silicon layer is exposed on a part of the substrate surface Wf and a hydrophobic surface is formed, a relatively large flow of hydrofluoric acid solution is supplied to the substrate surface Wf, so that the entire substrate surface Wf is covered with a chemical solution. However, the etching removal of the silicon oxide film can be continued. Thus, the chemical treatment (continuous chemical treatment) using the hydrofluoric acid solution with a large flow rate is performed for a predetermined time following the initial chemical treatment, and all the silicon oxide film remaining on the substrate surface Wf is removed by etching.

  When the above-described chemical process (initial chemical process + continuous chemical process) is executed and the desired etching process is completed, the set flow rate for hydrofluoric acid is set to zero and the supply of hydrofluoric acid to the mixing valve 22 is stopped. Then, the flow rate controller 38 adjusts the DIW flow rate to, for example, 2000 (mL / min) in response to a command from the control unit 14 in a state where the splash guard 46 is disposed at the height position for the rinsing process. Supply DIW. Thereby, DIW is pumped from the liquid supply unit 20 toward the nozzle 4 as a rinse liquid. Thus, the rinsing liquid supplied to the central portion of the substrate surface Wf receives centrifugal force to push out the hydrofluoric acid solution on the substrate surface Wf from the substrate surface Wf (rinsing process).

  When the rinsing process is completed, the control unit 14 closes the valve 18 to stop the discharge of the rinsing liquid from the nozzle 4, and at the same time or subsequently, the nozzle 4 is moved away from the space above the substrate W (not shown). ). Further, the control unit 14 controls the chuck rotation mechanism 8 to increase the rotation speed of the substrate W and perform spin drying.

  Finally, when the drying process of the substrate W is completed, the control unit 14 controls the chuck rotating mechanism 8 to stop the rotation of the substrate W. Then, the splash guard 46 is lowered to cause the spin chuck 2 to protrude from above the splash guard 46. Thereafter, the substrate transfer means carries out the processed substrate W from the apparatus, and a series of substrate processing for one substrate W is completed. Then, the same processing as described above is performed for the next substrate W.

  As described above, according to the present embodiment, the hydrofluoric acid solution (chemical solution) is supplied to the substrate surface Wf and the silicon oxide film adhering to the surface of the silicon substrate W is removed by etching (chemical solution process). In the chemical liquid process, after the initial chemical liquid processing is executed, the continuous chemical liquid processing is subsequently executed. In this initial chemical treatment, a silicon oxide film is formed on the substrate surface Wf, and the substrate surface Wf is a hydrophilic surface. Therefore, in the present embodiment, in the initial chemical solution treatment (from time 0 until time T1 elapses), the flow rate of the hydrofluoric acid solution is suppressed to 510 (mL / min) to suppress the usage amount of hydrofluoric acid. . On the other hand, the flow rate of the hydrofluoric acid solution is increased to 1530 (mL / min) at the timing when at least a part of the silicon layer of the substrate W is exposed by the initial chemical treatment, that is, at the timing when the time T1 has elapsed from the start of the chemical treatment. In this case, even if a silicon layer is exposed on a part of the substrate surface Wf and a hydrophobic surface is formed, the hydrofluoric acid solution covers the entire substrate surface Wf and removes the silicon oxide film by etching. Can be continued. In this way, while the substrate surface Wf is hydrophilic, the flow rate of the hydrofluoric acid solution (chemical solution) supplied to the substrate surface Wf is reduced, while the substrate surface Wf becomes hydrophobic as the chemical solution treatment proceeds. When it has, the flow rate of the hydrofluoric acid solution (chemical solution) is increased to cover the entire substrate surface Wf with the hydrofluoric acid solution. For this reason, it is possible to satisfactorily treat the substrate surface Wf while suppressing the amount of the hydrofluoric acid solution used.

  In this embodiment, the chemical flow rate is controlled during the chemical treatment, but the liquid supply unit 20 adjusts the concentration of the hydrofluoric acid solution so that the chemical concentration during the chemical treatment is always constant. For this reason, although the flow rate of the hydrofluoric acid solution supplied to the substrate surface Wf varies during the chemical treatment, the concentration of the hydrofluoric acid solution during the chemical treatment is kept constant, and the concentration unevenness on the substrate surface Wf is uneven. Generation | occurrence | production can be prevented effectively. In addition, it is the same also in other embodiment about the point which maintains the density | concentration of the hydrofluoric acid solution in this way during chemical | medical solution processing constant.

Second Embodiment
By the way, in the said 1st Embodiment, the hydrophobic condition of the substrate surface Wf is judged based on the elapsed time from the supply start of a hydrofluoric acid solution (chemical | medical solution). That is, the chemical treatment is started by supplying a hydrofluoric acid solution (chemical solution) to the substrate surface Wf, and the chemical treatment proceeds with time, and the hydrophobic state of the substrate surface Wf also changes. The time T1 at which at least a part of the silicon layer is exposed is stored in advance in a memory (not shown), and the flow rate switching timing of the hydrofluoric acid solution is controlled using this time T1. In order to obtain the time T1 with high accuracy, for example, a configuration for measuring the contact angle θ is added to the substrate processing apparatus as shown in FIGS. 4 and 5, and the flow rate switching timing shown in FIG. The derivation process may be executed. Hereinafter, a second embodiment of the present invention will be described with reference to FIGS.

  FIG. 4 is a diagram showing a second embodiment of the substrate processing apparatus according to the present invention. FIG. 5 is a schematic diagram showing the positional relationship between the droplet imaging camera and the substrate. Furthermore, FIG. 6 is a flowchart showing a flow rate switching timing derivation process in the second embodiment. The second embodiment is greatly different from the first embodiment in that a droplet forming nozzle 50 that discharges DIW droplets onto the substrate surface Wf and a droplet forming nozzle 50 to measure the contact angle. A liquid supply unit 52 that supplies DIW and drops liquid droplets from the nozzle 50 and a liquid droplet imaging camera 54 that images liquid droplets formed on the substrate surface Wf are provided. That is, in the second embodiment, when the droplet supply unit 52 sends DIW toward the nozzle 50, about 1 to 100 (μL) of droplets from the droplet forming nozzle 50 is stopped at the periphery of the substrate surface Wf. It is dripped at the part. Then, the droplet 56 formed on the substrate surface Wf is imaged by a droplet imaging camera 54 that is horizontally arranged at almost the same height as the substrate W as shown in FIG. Is sent to an image processing unit 58 provided in. In the control unit 14, predetermined image processing is performed by the image processing unit 58, and the contact angle θ of DIW with respect to the substrate surface Wf is obtained from the droplet image to determine whether the substrate surface Wf is hydrophilic or hydrophobic. It is possible. Since the other configuration is basically the same as that of the first embodiment, the description of the configuration is omitted here.

  Next, the derivation of the time T1 by the apparatus configured as described above will be described with reference to FIG. In the second embodiment, the control unit 14 lowers the splash guard 46 so that the spin chuck 2 protrudes from the upper end portion of the splash guard 46. In this state, the dummy substrate W is carried into the apparatus by the substrate carrying means (not shown). The “dummy substrate” has the same configuration as the substrate W to be processed, and the thickness of the silicon oxide film formed on the silicon layer of the substrate W is substantially the same as the substrate W to be processed. It has become. Then, the dummy substrate W is carried into the apparatus with the substrate surface Wf facing upward, and is held by the spin chuck 2. Subsequently, after the splash guard 46 is raised and the rotating substrate W is subjected to chemical processing for 570 seconds (step S1), rinsing processing and drying processing are performed (step S2). Note that the droplet forming nozzle 50 stands by at a position away from the substrate W while the chemical processing, the rinsing processing, and the drying processing are executed.

  In the next step S3, the count value N is set to zero. Then, after the droplet forming nozzle 50 is moved above the substrate surface Wf in the stopped state, a small amount of DIW is sent from the droplet supply unit 52 toward the nozzle 50 and is subjected to the chemical treatment for 570 seconds. A droplet 56 is formed on the surface Wf (step S4). When the droplet formation is completed in this way, the droplet forming nozzle 50 moves to the original standby position, while the droplet imaging camera 54 images the droplet 56.

  The image data of the droplet 56 sent from the droplet imaging camera 54 is subjected to image processing by the image processing unit 58 of the control unit 14, and then the control unit 14 determines the contact angle of the DIW with respect to the substrate surface Wf based on the droplet image. θ is measured (step S5). If the measured contact angle θ is 50 ° or more, it is determined that the substrate surface Wf is a hydrophobic surface, whereas if it is less than 50 °, it is determined that the substrate surface Wf remains a hydrophilic surface ( Step S6).

  While it is determined in step S6 that the substrate surface Wf remains a hydrophilic surface, steps S7 to S9 are executed, and then the process returns to step S4. That is, after the count value N is incremented by 1 in step S7, the chemical process is additionally performed for 15 seconds (step S8), and the rinsing process and the drying process are executed on the dummy substrate that has been subjected to the chemical process (step S8). S9). As a result, the chemical treatment is further added for 15 seconds, and the etching removal of the silicon oxide film proceeds by an amount corresponding to the “15 seconds”. As described above, while the silicon oxide film remains on the entire surface of the substrate, the chemical treatment is additionally performed in units of 15 seconds on the dummy substrate that has been subjected to the chemical treatment for 570 seconds.

  In addition, every time the chemical solution process is performed in units of 15 seconds, the process returns to step S4 to perform droplet formation, and after the contact angle θ is measured (step S5), the chemical solution process is additionally performed again. It is determined whether or not the processed substrate surface Wf is a hydrophobic surface (step S6).

When it is determined in step S6 that the contact angle θ is 50 ° or more and the substrate surface Wf is a hydrophobic surface, the following equation is given: Time T1 = 570 + 15 × N (seconds)
Based on the above, the time T1, that is, the time during which at least a part of the silicon layer of the substrate W is exposed by the chemical treatment is obtained and stored in the memory (step S10). Then, the dummy substrate is unloaded from the apparatus.

  As described above, according to the second embodiment of the present invention, the time T1 is measured using a dummy substrate that is substantially the same as the substrate W to be processed, so that the time T1 can be accurately obtained. The chemical liquid flow rate can be appropriately switched. In the second embodiment, the time T1 is measured using a dummy substrate. However, the time T1 may be measured using the first substrate W among a plurality of substrates to be processed. . However, in this case, after obtaining the time T1 (step S10), it is necessary to continuously execute the continuous chemical solution process, the rinse process, and the drying process.

  Moreover, in the said 2nd Embodiment, although the structure for measuring contact angle (theta) with respect to a substrate processing apparatus is added, you may measure contact angle (theta) with another apparatus. That is, the substrate subjected to the rinse treatment and the drying treatment after the chemical treatment for 570 seconds is taken out from the substrate processing apparatus, and the contact angle θ is set using, for example, a wafer cleaning / processing evaluation apparatus “MR700R” manufactured by Kyowa Interface Chemical Co., Ltd. Measured, while the contact angle θ is less than 50 ° and the substrate surface is determined to be hydrophilic, every time (15 seconds of chemical treatment + rinse treatment + drying treatment) is performed using the substrate treatment apparatus, The contact angle may be measured by the wafer cleaning / processing evaluation apparatus.

<Third Embodiment>
Further, as a method for determining the hydrophobic state of the substrate surface Wf, in addition to the method based on the elapsed time from the start of the supply of the hydrofluoric acid solution (chemical solution), the hydrophobicity of the substrate surface based on the image obtained by imaging the substrate surface Wf. You may judge the situation. Hereinafter, a third embodiment of the present invention will be described with reference to FIGS.

  FIG. 7 is a view showing a third embodiment of the substrate processing apparatus according to the present invention. FIG. 8 is a schematic diagram showing the positional relationship between the substrate and the surface imaging camera that images the substrate surface. FIG. 9 is a flowchart showing a reference value acquisition process for obtaining a reference value for determining the hydrophobic state. FIG. 10 is a flowchart showing the operation of the third embodiment. The third embodiment is greatly different from the first embodiment in that a surface imaging camera 60 for capturing an image of the substrate surface is disposed above the substrate W. Then, the surface of the substrate is imaged by the surface imaging camera 60, and the image data is sent to the image processing unit 62 provided in the control unit 14. In the control unit 14, the image processing unit 62 performs a filtering process using, for example, a Sobel filter on the image data to enhance the edge. Therefore, when at least a part of the silicon layer of the substrate W is exposed and a streak pattern is generated during the chemical treatment, the edge-enhanced substrate surface image becomes relatively bright by the amount of the streak pattern. ing. On the other hand, the generation of the streak pattern is not recognized while the chemical treatment is being performed well, and the edge-enhanced substrate surface image is darker than the image having the streak pattern. In this way, it is possible to determine the hydrophobic state of the substrate surface Wf based on image information obtained by applying appropriate image processing to the image of the substrate surface. Note that the edge enhancement processing is not limited to the filtering processing, and conventionally known image processing can be used. Further, since the other configuration is basically the same as that of the first embodiment, the description of the configuration is omitted here.

  Next, the substrate processing by the apparatus configured as described above will be described. In the third embodiment, since the hydrophobic state of the substrate surface Wf is determined based on the image of the substrate surface, the two types of dummy substrates, that is, the hydrophobic substrate and the hydrophilic substrate are used prior to the substrate processing. The value is derived. Specifically, a silicon substrate on which no silicon oxide film is formed is prepared as a hydrophobic substrate, and a substrate on which a silicon oxide film is formed on the substrate surface is prepared as a hydrophilic substrate. Then, as shown in FIG. 9, steps S21 to S29 are executed to derive the reference value μ3 for the above determination.

  When the hydrophobic substrate W is carried into the apparatus with the substrate surface Wf facing upward and is held by the spin chuck 2 (step S21), the splash guard 46 is raised and steps S22 to S24 are executed. . That is, the hydrophobic substrate W held on the spin chuck 2 is rotated by driving the chuck rotating mechanism 8. On the other hand, in the liquid supply unit 20, a hydrofluoric acid solution having a desired concentration (50: 1) and a desired flow rate (510 (mL / min) in this embodiment) is used as a chemical solution as in the first embodiment. Prepared. Then, by opening the valve 18, a hydrofluoric acid solution having a desired concentration is supplied from the nozzle 4 to the substrate surface Wf at 510 (mL / min). Further, after the hydrofluoric acid solution (chemical solution) spreads over the entire substrate surface Wf, a plurality of, for example, five images of the substrate surface Wf are captured by the surface imaging camera 60 (step S22). Each image data obtained in this way is sent to the image processing unit 62 of the control unit 14, and edge enhancement processing is executed by filtering processing using a Sobel filter (Step S23). The average brightness μ1 of the image of the substrate surface Wf that has been subjected to the edge enhancement processing is obtained and temporarily stored in a memory (not shown) (step S24). When the derivation of the average brightness μ1 is completed, the supply of the hydrofluoric acid solution is stopped, the rinse treatment and the drying treatment are performed, and then the hydrophobic dummy substrate is carried out.

  In addition, processing similar to that for the hydrophobic dummy substrate (steps S25 to S28) is performed on the hydrophilic dummy substrate. That is, when the hydrophilic substrate W is carried into the apparatus with the substrate surface Wf facing upward and is held by the spin chuck 2 (step S25), the splash guard 46 is raised and the chuck rotating mechanism 8 is driven. Thus, the hydrophilic substrate W held on the spin chuck 2 is rotated. Then, by opening the valve 18, a hydrofluoric acid solution having a desired concentration is supplied from the nozzle 4 to the substrate surface Wf at 510 (mL / min). Further, after the hydrofluoric acid solution (chemical solution) spreads over the entire substrate surface Wf, a plurality of, for example, five images of the substrate surface Wf are captured by the surface imaging camera 60 (step S26). Edge enhancement processing is executed for each image data obtained in this way (step S27). Further, the average brightness μ2 of the image of the substrate surface Wf that has been subjected to the edge enhancement processing is obtained and temporarily stored in a memory (not shown) (step S28). When the derivation of the average brightness μ2 is completed, the supply of the hydrofluoric acid solution is stopped, the rinse treatment and the drying treatment are performed, and then the hydrophilic dummy substrate is carried out.

  When the average brightness μ1 on the hydrophobic substrate W thus determined and the average brightness μ2 on the hydrophilic substrate W are compared, the former shows a higher value than the latter. The reason is as follows. When the hydrofluoric acid solution is supplied to the hydrophilic substrate W, the hydrofluoric acid solution is uniform even if the flow rate of the hydrofluoric acid solution is relatively low (510 (mL / min) in this embodiment). Spread over the entire substrate surface Wf. On the other hand, when the hydrofluoric acid solution is supplied to the hydrophobic substrate W at a relatively low flow rate, the hydrofluoric acid solution does not spread uniformly over the entire substrate surface Wf, and a streak pattern is generated to enhance the edge. This is because the image of the substrate surface Wf becomes brighter than the image of the hydrophilic substrate W by the amount of the streak pattern. Therefore, in the present embodiment, the average value of the two types of brightness μ1 and μ2 obtained in this way is calculated and stored in the memory as a reference value μ3 (step S29). That is, when the brightness μ4 obtained from the image of the substrate surface Wf is the reference value μ3 or more, the substrate surface Wf is a hydrophobic surface, whereas when the brightness μ4 is less than the reference value μ3. It can be determined that the substrate surface Wf is a hydrophilic surface. In this embodiment, the average value of the two types of brightness μ1 and μ2 is used as the reference value μ3. However, the calculation method of the reference value μ3 is not limited to this, and for example, the two brightnesses μ1 and μ2 are used. The reference value μ3 may be set after weighting.

  When the reference value μ3 is obtained as described above, the substrate processing is performed as shown in FIG. That is, in the substrate processing apparatus according to the third embodiment, the control unit 14 controls each part of the apparatus according to a program stored in a memory (not shown) to observe the hydrophobic state of the substrate surface Wf with respect to the substrate W. Then, after performing the chemical treatment, rinse treatment and drying treatment are performed.

  The control unit 14 lowers the splash guard 46 so that the spin chuck 2 protrudes from the upper end portion of the splash guard 46. In this state, an unprocessed substrate W is carried into the apparatus by the substrate transport means (not shown) (step S31). Then, the nozzle 4 is moved above the central portion of the substrate surface Wf, and the substrate W held on the spin chuck 2 by driving the chuck rotating mechanism 8 is rotated at a rotation speed (for example, 800 rpm) determined within a range of 200 to 1200 rpm. Rotate. On the other hand, in the liquid supply unit 20, as in the first embodiment, a hydrofluoric acid solution having a desired concentration (50: 1) and a desired flow rate (510 (mL / min) in this embodiment) is prepared as a chemical solution. Then, by opening the valve 18, a hydrofluoric acid solution having a desired concentration is supplied from the nozzle 4 to the substrate surface Wf at 510 (mL / min) (step S32), and chemical processing is started. This chemical processing is executed until “YES” is determined in step S33, and a plurality of images of the substrate surface are taken during the chemical processing in the same manner as the reference value acquisition processing (step S34). After performing the edge enhancement process (step S35), the average image brightness μ4 is obtained (step S36).

  Further, the image average brightness μ4 obtained in this way is compared with the reference value μ3, and it is determined whether the substrate surface Wf at the present time during the chemical treatment is a hydrophilic surface or a hydrophobic surface (step S37). More specifically, when the average image brightness μ4 is less than the reference value μ3, it is determined that the substrate surface Wf is a hydrophilic surface, and the process returns to step S33 and the chemical treatment is continued with the low flow rate. On the other hand, when the image average brightness μ4 is equal to or larger than the reference value μ3, it is determined that the hydrofluoric acid solution does not spread over the entire substrate surface Wf at the current chemical flow rate, and it is difficult to perform the chemical treatment well. To do. Therefore, after increasing the chemical flow rate (step S38), the process returns to step S33 to continue the chemical processing. Here, the increase in the chemical flow rate in step S38 may be increased from 510 (mL / min) to 1530 (mL / min) at a stretch as in the first and second embodiments, but in this embodiment, Since the hydrophobic state of the substrate surface Wf can be detected in real time, the increase in the chemical flow rate is set to several tens or several hundreds (mL / min), and the chemical flow rate is gradually increased as the chemical treatment progresses. You may let them.

  When the initial chemical process performed at the flow rate of 510 (mL / min) and the continuous chemical process performed by increasing the chemical flow rate are executed to complete the chemical process, that is, when “YES” is determined in step S33, The rinse process and the drying process are executed in the same manner as in the embodiment (step S39). Finally, the control unit 14 controls the chuck rotating mechanism 8 to stop the rotation of the substrate W, and then the substrate transport means unloads the processed substrate W from the apparatus (step S40).

  As described above, according to the third embodiment, since the hydrophobic state of the substrate surface Wf is determined based on the image obtained by imaging the substrate surface Wf, the chemical liquid flow rate is switched at a more accurate timing. The amount of the chemical solution used can be more effectively suppressed, and the substrate surface can be treated better. In the present embodiment, the substrate surface Wf is imaged continuously or intermittently during the chemical treatment to obtain images, and based on image information indicating the substrate surface Wf obtained by performing image processing on each image. Since the hydrophobic state is also determined, the hydrophobic state of the substrate surface Wf, which changes every moment, can be determined directly and in real time.

<Others>
The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above embodiment, the substrate surface Wf is etched using the hydrofluoric acid solution as the “chemical solution” of the present invention, but the application target of the present invention is not limited to this, and the chemical solution is applied to the substrate W. The present invention can be applied to all substrate processing methods and apparatuses for supplying chemical substances to the substrate W and performing chemical treatment on the substrate W.

  The present invention generally relates to substrates including semiconductor wafers, photomask glass substrates, liquid crystal display glass substrates, plasma display glass substrates, FED substrates, optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, and the like. The present invention can be applied to a substrate processing method and a substrate processing apparatus in which a chemical solution is supplied to the surface of the substrate to perform a chemical treatment on the substrate.

1 is a diagram showing a first embodiment of a substrate processing apparatus according to the present invention. It is a block diagram which shows the electric constitution of the apparatus shown in FIG. It is a figure which shows the chemical | medical solution process in the apparatus shown in FIG. It is a figure which shows 2nd Embodiment of the substrate processing apparatus concerning this invention. It is a schematic diagram which shows the positional relationship of a droplet imaging camera and a board | substrate. It is a flowchart which shows the derivation | leading-out process of the flow volume switching timing in 2nd Embodiment. It is a figure which shows 3rd Embodiment of the substrate processing apparatus concerning this invention. It is a schematic diagram which shows the positional relationship of the surface imaging camera which images the surface of a board | substrate, and a board | substrate. It is a flowchart which shows the reference value acquisition process which calculates | requires the reference value for judging a hydrophobic condition. It is a flowchart which shows operation | movement of 3rd Embodiment.

Explanation of symbols

14 ... Control unit (control means)
DESCRIPTION OF SYMBOLS 20 ... Liquid supply unit 24 ... Hydrofluoric acid supply source 34 ... DIW supply source 38 ... Flow controller for DIW 40 ... Flow control valve 42 ... Flow meter 48 ... DIW supply unit 50 ... Nozzle for droplet formation 52 ... Droplet supply unit 54 ... Droplet imaging camera 56 ... Droplet 58, 62 ... Image processing unit 60 ... Surface imaging camera (imaging means)
T1 ... (low flow) time Wf ... substrate surface W ... substrate

Claims (9)

In the substrate processing method of supplying a chemical solution to the surface of the substrate and performing a chemical solution treatment on the substrate,
A substrate processing method, comprising: controlling a flow rate of the chemical solution supplied to the substrate surface according to a hydrophobic state of the substrate surface during the chemical treatment.   The substrate processing method according to claim 1, wherein the flow rate of the chemical solution is controlled by determining a hydrophobic state of the substrate surface based on an elapsed time from the start of supply of the chemical solution.   The substrate processing method according to claim 1, wherein the flow rate of the chemical solution is controlled by determining a hydrophobic state of the substrate surface based on an image obtained by imaging the substrate surface.   Claims: The substrate surface is imaged continuously or intermittently during the chemical treatment to obtain images, and the hydrophobic state is determined based on image information indicating the substrate surface obtained by performing image processing on each image. Item 4. A substrate processing method according to Item 3.   The substrate processing method according to claim 1, wherein a concentration of the chemical solution during the chemical treatment is constant. In a substrate processing apparatus for supplying a chemical solution to the surface of a substrate and performing a chemical treatment on the substrate,
A nozzle for discharging a chemical toward the substrate surface;
A liquid supply unit that supplies the chemical liquid to the nozzle while adjusting the flow rate of the chemical liquid;
A substrate processing apparatus comprising: control means for controlling the flow rate of the chemical liquid supplied to the substrate surface by controlling the liquid supply unit according to a hydrophobic state of the substrate surface during the chemical liquid processing. .   The substrate processing apparatus according to claim 6, wherein the control unit measures an elapsed time from the start of supply of the chemical solution, determines a hydrophobic state of the substrate surface based on the elapsed time, and controls the flow rate of the chemical solution. It further comprises imaging means for imaging the substrate surface,
The substrate processing apparatus according to claim 6, wherein the control unit determines a hydrophobic state of the substrate surface based on an image of the substrate surface imaged by the imaging unit and controls the flow rate of the chemical solution.   The substrate processing apparatus according to claim 6, wherein the liquid supply unit maintains a constant chemical concentration during the chemical processing.

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