JP2009147038A - Substrate treating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To excellently treat a substrate surface while suppressing the consumption of a treatment liquid. <P>SOLUTION: While a substrate W is rotated at a first rotational speed (for example, 1,000 r.p.m.), hydrofluoric acid is supplied from a chemical discharge nozzle 4 to a substrate surface Wf at a first flow rate of, for example, 2 (L/min). Consequently, a hydrofluoric acid film 27 having a thickness T1 is formed on the entire substrate surface Wf, which becomes well wet with hydrofluoric acid. While the discharge flow rate of the hydrofluoric acid from the chemical discharge nozzle 4 is held at 2 (L/min), the rotational speed of the substrate W is reduced to a second rotational speed of, for example, 10 r.p.m. slower than the first rotational speed (second stage). Thus, the rotational speed is reduced to form a liquid swell 28 having a thickness T2 (>T1) on the substrate surface Wf. In a third stage after the swell formation, the hydrofluoric acid is discharged from the nozzle 4 further continuously to maintain the liquid swell state, thereby always supplying fresh hydrofluoric acid. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a substrate processing method for supplying a processing liquid onto a surface of a substrate and processing the substrate surface. 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 is performed as necessary (see Patent Document 1). In the invention described in Patent Document 1, a hydrofluoric acid solution (treatment liquid) is supplied at a flow rate of, for example, 1000 (mL / min) for 1 minute while rotating the substrate at a high speed (for example, 300 rpm) by a rotation mechanism, and the natural on the substrate is The oxide film is removed. Recently, a so-called hydrophobic substrate is provided in which the contact angle of the substrate surface with respect to the processing liquid exceeds 50 °. However, when performing substrate processing using the processing liquid on such a hydrophobic substrate. The flow rate of the processing liquid is increased to, for example, 1500 (mL / min), and the rotation speed of the substrate is increased to, for example, 800 rpm.

JP-A-9-38595 (paragraph 0025)

  As described above, in the prior art, the substrate is rotated at a relatively high rotational speed, and a relatively large flow rate of processing liquid is supplied to the substrate surface to execute a cleaning process on the substrate. For this reason, the usage-amount of the process liquid has increased. Here, if the flow rate of the processing liquid is reduced in order to reduce the amount used, the processing liquid does not reach the entire surface of the substrate, and the cleaning process or the like becomes uneven. Therefore, in order to process the substrate surface satisfactorily, a large amount of processing liquid is necessary.

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

  A substrate processing method according to the present invention is a substrate processing method for processing a substrate with a processing liquid while supplying the processing liquid toward the surface of the substrate, and the substrate is rotated at a first rotation speed in order to achieve the above object. A first step of supplying the processing liquid to the central portion of the substrate at a first flow rate and spreading the processing liquid over the entire surface of the substrate, and a second rotational speed lower than the first rotational speed after the first step. The second step of forming the liquid volume of the processing liquid on the substrate surface by slowing down to the second flow rate, and after the second step, the flow rate of the processing liquid is reduced to a second flow rate lower than the first flow rate while maintaining the liquid buildup state. And a third step.

  In the invention configured as described above, the liquid volume of the processing liquid is formed on the substrate surface and the substrate surface is processed, but the liquid volume is formed in two stages of the first process and the second process. ing. That is, in the first step, a relatively high flow rate of processing liquid is supplied to the central portion of the surface of the substrate rotating at a relatively high rotation (first rotation speed), so that the entire substrate surface can be processed in a short time. Liquid spreads. Subsequently, the rotation speed of the substrate is reduced to the second rotation speed, and a liquid pile having a thickness suitable for substrate processing is formed on the substrate surface. For this reason, the processing is started almost simultaneously in each part of the substrate surface, and the processing can be made uniform in the substrate surface. This point will be further described in detail later with reference to examples.

  In addition, by forming the liquid volume in this manner, the processing liquid constituting the liquid volume executes processing on the substrate surface, but the present invention sets the flow rate of the processing liquid to a second flow rate that is smaller than the first flow rate. The amount of liquid was reduced and the processing liquid was further supplied to continue the liquid accumulation state. For this reason, a fresh process liquid is always supplied with respect to the liquid puddle, and a substrate process is performed. As a result, good substrate processing can be continuously performed. In addition, since the processing liquid is supplied by reducing the flow rate of the processing liquid to a second flow rate that is smaller than the first flow rate, the processing liquid is processed in comparison with the conventional technique in which the processing liquid is continuously supplied at a relatively high flow rate. The amount of liquid used can be greatly reduced. This point will also be described in detail later with reference to examples.

  Here, comparing the first step and the second step, the substrate rotates at a relatively high speed (first rotation speed) in the first step, whereas the rotation speed of the substrate in the second step is second. Reduced to rotational speed. Therefore, the movement time until the processing liquid supplied to the substrate surface in the first step reaches the peripheral edge of the substrate is shorter than that in the second step, and if the processing liquid is continuously supplied beyond the movement time. Then, the processing liquid scatters from the substrate, and the amount of processing liquid used increases. Therefore, it is desirable to set the execution time of the first step to be shorter than the execution time of the second step from the viewpoint of reducing the amount of processing liquid used.

  Further, from the viewpoint of reducing the amount of processing liquid used, the total amount of processing liquid supplied to the substrate surface in the third step is less than the total amount of processing liquid supplied to the substrate surface in the first step and second step. It is desirable to set so that

  Further, in the third step, a fresh processing liquid is supplied to the liquid puddle formed in the second step to prevent the processing speed of the substrate from being changed by the processing liquid. As a result of the displacement, the fresh processing liquid is supplied to each part of the liquid pile, and the entire substrate surface can be processed at a uniform processing speed. In particular, in the present invention, since the substrate processing is performed with the processing liquid in a liquid state while rotating the substrate, the supply position of the processing liquid is displaced from the central portion of the surface of the substrate to the peripheral portion of the surface, so that the entire liquid is filled. On the other hand, the processing liquid can be replenished evenly, and the substrate processing can be performed more uniformly.

  According to the present invention, the processing liquid is supplied to the central portion of the surface of the substrate rotating at the first rotational speed at the first flow rate to spread the processing liquid over the entire substrate surface, and then the rotational speed of the substrate is reduced. A puddle of processing liquid is formed on the substrate surface. In addition, after the liquid buildup is formed, the substrate processing is performed by reducing the flow rate of the processing liquid to a second flow rate that is smaller than the first flow rate while maintaining the liquid buildup state. Therefore, the substrate surface can be uniformly processed while suppressing the amount of the treatment liquid used.

  FIG. 1 is a diagram showing an example of a substrate processing apparatus suitable for executing the substrate processing method according to the present invention. This substrate processing apparatus is a single-wafer type substrate processing apparatus used for a cleaning process for removing unnecessary substances adhering to a surface Wf of a substrate W such as a semiconductor wafer. More specifically, the substrate surface Wf is sequentially subjected to chemical treatment with a chemical solution such as hydrofluoric acid and rinse treatment with a rinse solution such as pure water or DIW (deionized water). This is an apparatus for drying the wet substrate surface Wf.

  The substrate processing apparatus includes a spin chuck 2 that rotates while holding the substrate W in a substantially horizontal posture with the substrate surface Wf facing upward, and a chemical solution toward the surface Wf of the substrate W held by the spin chuck 2. A chemical liquid discharge nozzle 4 for discharging, and a rinse discharge nozzle (not shown) for discharging a rinsing liquid onto the substrate W that has been subjected to a chemical liquid treatment with the chemical liquid are provided.

  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. A disc-shaped spin base 12 is integrally connected to the upper end portion of the rotation spindle 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 chemical liquid discharge nozzle 4 is connected to a chemical liquid supply unit 20 via a chemical liquid valve 18. This chemical supply unit 20 not only discharges a chemical suitable for substrate cleaning such as hydrofluoric acid or BHF (Buffered Hydrofluoric acid) to the nozzle 4 side, but also can dynamically change the flow rate. It has become. Then, based on the control command from the control unit 14, when the chemical solution supply unit 20 controls the supply flow rate of the chemical solution and the chemical solution valve 18 is opened, the chemical solution is pumped from the chemical solution supply unit 20 toward the chemical solution discharge nozzle 4. Then, the chemical liquid is discharged from the chemical liquid discharge nozzle 4 at a flow rate set by the control unit 14. Note that a nozzle moving mechanism 22 is connected to the chemical liquid discharge nozzle 4, and the nozzle moving mechanism 22 is driven in accordance with an operation command from the control unit 14, so that the discharge area and the discharge area above the surface of the substrate W are discharged. The nozzle 4 can move between the standby position retracted from the side to the side. Also in the discharge region, the nozzle 4 can reciprocate between the upper portion of the substrate surface Wf and the upper peripheral portion thereof by the nozzle moving mechanism 22.

  Although not shown, a rinse liquid discharge nozzle and a rinse liquid supply unit are provided in the same manner as the nozzle 4 and the chemical liquid supply unit 20 described above, and the rinse liquid is directed toward the substrate W that has been subjected to the chemical liquid treatment. The rinsing process can be executed by discharging.

  A receiving member 24 is fixedly attached around the casing 10. Three cylindrical partition members are erected on the receiving member 24. And three spaces are formed as a drainage tank by the combination of these partition members and the casing 10. A splash guard 26 is provided above these drainage tanks 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 26 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 26 is lifted and lowered stepwise by driving a guard lifting mechanism (not shown), whereby the chemical liquid and the rinsing liquid scattered from the rotating substrate W can be separated and drained.

  Next, an embodiment of the substrate processing method according to the present invention will be described in detail with reference to FIG. In the figure, the uppermost stage is a graph showing the rotation speed of the substrate W held by the spin chuck 2, and the middle stage is a graph showing the flow rate of the chemical liquid discharged from the chemical liquid discharge nozzle 4 toward the substrate surface Wf. The lowermost stage is a diagram schematically showing a liquid film and a liquid pile formed on the surface Wf of the substrate W. In this embodiment, the control unit 14 controls each part of the apparatus according to a program stored in a memory (not shown) to perform a chemical treatment, a rinsing process, and a drying process on the substrate W. Among these, the chemical treatment corresponds to the “treatment” of the present invention, and is largely composed of three steps. A chemical solution such as hydrofluoric acid used in the chemical solution treatment corresponds to the “treatment solution” of the present invention.

  The control unit 14 lowers the splash guard 26 and causes the spin chuck 2 to protrude from the upper end portion of the splash guard 26. 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 26 is raised by one step and the chemical treatment for the substrate W is started.

  In the first step of the chemical treatment, that is, the first step, the chemical discharge nozzle 4 is moved above the center of the substrate surface Wf, and the substrate W held on the spin chuck 2 by driving the chuck rotating mechanism 8 is 200 to 1200 rpm. Rotate at a first rotation speed (for example, 1000 rpm) determined within the range. On the other hand, in the chemical solution supply unit 20, hydrofluoric acid is prepared as a chemical solution, and its flow rate is adjusted to a first flow rate, for example, 2 liters per minute. Then, by opening the chemical liquid valve 18, hydrofluoric acid is supplied to the substrate surface Wf from the chemical liquid discharge nozzle 4 to the substrate surface Wf at 2 (L / min). In this first step, since the substrate W is rotating at a relatively high rotational speed as described above, the hydrofluoric acid supplied to the central portion of the substrate surface Wf is instantly spread by centrifugal force, and the substrate made of hydrofluoric acid. The etching process (chemical solution process) of the surface Wf is performed as a whole and almost simultaneously, and a uniform etching process is started.

  In addition, a very thin hydrofluoric acid liquid film 27 having a thickness T1 is formed on the entire substrate surface Wf, and the entire substrate surface Wf is in a state of being familiar with hydrofluoric acid (chemical solution). In the present embodiment, the first step is intended not only to increase the uniformity of etching by instantaneously spreading hydrofluoric acid over the entire substrate surface Wf, but also to blend in with hydrofluoric acid. Therefore, it is desirable to end the first step when the entire substrate surface Wf is covered with hydrofluoric acid. Even if hydrofluoric acid is further supplied after the entire substrate surface Wf is covered with hydrofluoric acid, the thickness of the hydrofluoric acid thin film 27 does not increase, and hydrofluoric acid is shaken off as an excess from the substrate W. This is because the amount of hydrofluoric acid used increases. For example, when the chemical treatment is set to 1 minute as in the prior art or later examples, it is desirable to set it within 5 seconds. That is, by setting the execution time of the first step to about 1 to 5 seconds, the effect of allowing the entire substrate surface Wf to become familiar with hydrofluoric acid while reducing the amount of hydrofluoric acid used can be obtained.

  Next, the rotation speed of the substrate W is reduced to a second rotation speed lower than the first rotation speed, for example, 10 rpm, while maintaining the discharge flow rate of hydrofluoric acid from the chemical solution discharge nozzle 4 at 2 (L / min). (Second step). By decelerating the rotational speed in this way, a liquid pile 28 having a thickness T2 (> T1) is formed on the substrate surface Wf. The thickness T2 of the liquid deposit 28 can be adjusted by controlling the rotation speed of the substrate W, and is preferably adjusted according to the concentration of hydrofluoric acid, the state of the substrate surface Wf, and the like. By forming the liquid deposit 28 in this way, even if the hydrofluoric acid discharge from the nozzle 4 is stopped, the etching process proceeds. However, as will be described later, when the etching process (chemical solution process) proceeds while the supply of hydrofluoric acid is stopped, the concentration of reactive species that contribute to the etching reaction contained in the liquid deposit 28 decreases as the etching process proceeds. On the other hand, the etching reaction product remains on the substrate surface Wf, and there arises a problem that the etching process does not proceed even after a lapse of time.

  Therefore, in the present embodiment, when the liquid deposit 28 is formed as described above, the third step is executed following the second step. In this third step, the chemical solution supply unit 20 reduces the flow rate of hydrofluoric acid to a second flow rate lower than the first flow rate, for example, 0.5 liters per minute while keeping the rotation speed of the substrate W at the second rotation speed. After adjusting, hydrofluoric acid is supplied from the nozzle 4 to the liquid puddle 28. Since fresh hydrofluoric acid is replenished during the etching process in this way, it is possible to prevent the concentration of reactive species contributing to the etching reaction from being lowered while maintaining the liquid accumulation state, and the substrate W due to hydrofluoric acid. The etching rate (processing rate) can be stabilized. In addition, the supply of a new solution of hydrofluoric acid pushes out the reaction product from the etching process from the substrate surface Wf and prevents it from remaining on the substrate surface Wf. Therefore, the etching process can be performed satisfactorily.

  In the third step of the present embodiment, the nozzle moving mechanism 22 drives the nozzle 4 to cause the nozzle 4 to reciprocate between the position above the center of the substrate surface Wf and the position above the peripheral edge. In this way, by scanning the nozzle 4 while discharging the hydrofluoric acid from the nozzle 4, fresh hydrofluoric acid is supplied to each part of the liquid pool 28, and the entire substrate surface Wf can be processed at a more uniform processing speed. Etching can be performed.

  When the above-described third step is continued for a predetermined time and the desired etching process is completed, the chemical solution discharge nozzle 4 is moved to the standby position. Then, the rinsing process and the drying process are performed on the substrate W in a state where the splash guard 26 is disposed at the height position for the rinsing process. In this embodiment, those rinse treatments and drying treatments that have been conventionally used are employed, and the details of the treatments are well known in the art, and thus the description thereof is omitted here.

  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 26 is lowered to cause the spin chuck 2 to protrude from above the splash guard 26. 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 this embodiment, the hydrofluoric acid liquid deposit 28 is formed on the substrate surface Wf and the substrate surface Wf is subjected to the etching process. A thin hydrofluoric acid liquid film 27 is formed over the entire substrate surface Wf over time, and after the entire substrate surface Wf is made acclimatized with hydrofluoric acid, the liquid puddle 28 is formed. Therefore, the etching process is started almost simultaneously on each part of the substrate surface Wf, and the etching process (chemical solution process) in the substrate surface Wf is made uniform.

  In addition, in the third step after the liquid formation, the hydrofluoric acid is further continuously discharged from the nozzle 4 and the liquid accumulation state is continued, so that fresh hydrofluoric acid is always supplied to the liquid accumulation 28. An etching process is performed. As a result, a good etching process can be continuously performed. In addition, in this third step, the hydrofluoric acid is continuously supplied while the flow rate of hydrofluoric acid is reduced to a second flow rate that is smaller than the first flow rate, so that the hydrofluoric acid is continuously supplied at a relatively high flow rate. The amount of hydrofluoric acid used can be greatly reduced as compared with the conventional technology supplied to the company.

  Moreover, in the above embodiment, the nozzle 4 is reciprocally scanned between the upper portion of the substrate surface Wf and the upper peripheral portion while rotating the substrate W, so that the supply position of hydrofluoric acid is changed from the central portion of the surface of the substrate W to the peripheral portion of the surface. Therefore, the hydrofluoric acid can be replenished evenly to the entire liquid pile 28, and the etching process can be performed more uniformly.

  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-described embodiment, the chemical solution supply unit 20 is configured to be able to dynamically change the flow rate of the chemical solution, and discharges the chemical solutions having different flow rates from one nozzle 4, but may be configured as follows. Good. FIG. 3 is a view showing another embodiment of the substrate processing method according to the present invention. In this embodiment, the chemical solution supply unit 20 is configured to be capable of pumping the chemical solution at two different flow rates in advance, and is provided with two nozzles 4A and 4B correspondingly. From the chemical solution supply unit 20, a pipe 30A for pumping the chemical solution at a first flow rate (2 liters per minute) and a pipe 30B for pumping the chemical solution at a second flow rate (0.5 liters per minute) are extended. The pipes 30A and 30B are connected to the nozzles 4A and 4B, respectively. In addition, a chemical valve 18A is inserted in the pipe 30A, while a chemical valve 18B is inserted in the pipe 30B. Then, the chemical liquid valves 18A and 18B are independently opened and closed in accordance with an opening / closing command from the control unit 14, whereby the chemical liquid can be discharged toward the substrate surface Wf at a desired flow rate.

  In the above embodiment, the substrate surface Wf is etched using hydrofluoric acid as the “treatment liquid” of the present invention. However, the application target of the present invention is not limited to this, and the treatment liquid is The present invention can be applied to all substrate processing methods for supplying a substrate W and performing a predetermined process on the substrate W.

  In the above embodiment, the nozzle 4 is reciprocally scanned in the third step. However, even when the third step is executed with the nozzle 4 fixedly disposed above the center of the substrate surface Wf, the nozzle 4 is compared with the prior art. As a result, the effect of reducing the amount used and the improvement of the uniformity of treatment were recognized.

  Next, examples of the present invention will be shown. However, the present invention is not limited by the following examples as a matter of course, and it is needless to say that the present invention can be implemented with appropriate modifications within a range that can meet the gist of the preceding and following descriptions. These are all included in the technical scope of the present invention.

  Here, in order to clarify the technical significance of the above-described embodiment, a substrate in which a thermal oxide film of about 100 nm is formed on a silicon substrate is prepared, and a sheet made by Dainippon Screen Mfg. Co., Ltd. Cleaning processing (chemical solution processing + rinsing processing + drying processing) was performed using the leaf cleaning device SU-3100. The chemical treatment at that time uses hydrofluoric acid as the treatment solution, and the treatment conditions are shown in “Examples” in Table 1. The concentration of hydrofluoric acid was about 1% (0.96%) in which 49% hydrofluoric acid was mixed with pure water (1:50).

The substrate rotation speed and the chemical flow rate in the “first step”, “second step”, and “third step” in the processing conditions in the table are the following values as in the above embodiment. First step : Rotational speed = 1000 rpm, flow rate = 2 (L / min)
Second step: rotational speed = 10 rpm, flow rate = 2 (L / min)
Third step: rotational speed = 10 rpm, flow rate = 0.5 (L / min)
Is set. Further, before and after the above-described cleaning process was performed, the thickness of the thermal oxide film was measured with an ellipsometer FX-200 manufactured by KLA-Tencor at 49 locations on the entire surface of the substrate. And the usage-amount of the chemical | medical solution used by the etching process (chemical | medical solution process), the uniformity of an etching process, and an etching rate are evaluated, and the result is put together in the same table. The “use amount” is calculated based on the flow rate of the chemical solution and the processing conditions (discharge time). “Uniformity” is obtained by calculating the etching amount from the film thickness measurement values for each of the 49 locations described above, and then calculating the maximum etching amount Max, the minimum etching amount Min, and the average etching amount Average as follows: Uniformity) = (Max−Min) / (2 × Average)
The value obtained by substituting for. Furthermore, the “etching rate” was calculated based on the etching amount and processing time for a plurality of substrates, and qualitatively evaluated based on the variation in the calculation results.

Also, in order to verify the technical significance of the first to third steps, the processing conditions in the etching process are as follows: Conventional example (only the first step),
-Comparative example 1 (3rd process only),
-Comparative example 2 (2nd process + 3rd process),
-Comparative example 3 (1st process + 2nd process) However, in the 2nd process of the comparative example 3, a chemical supply is stopped after liquid accumulation formation,
The same verification as in the above embodiment was performed, and the verification results are summarized in Table 1.

  As can be seen by comparing the example and the conventional example, according to the example, the uniformity equal to or higher than that of the conventional example can be obtained while greatly reducing the amount of use.

  In Comparative Examples 1 and 2, since the chemical solution is supplied to the entire surface of the substrate while omitting the first step and rotating the substrate at a low speed (10 rpm), when the supplied chemical solution spreads on the substrate surface, First, the central part of the surface comes into contact with the liquid first, and then the chemical spreads to the peripheral part of the substrate. . In particular, by comparing Example and Comparative Example 2, it is technically important to improve uniformity and to form a liquid film of a chemical solution over the entire substrate surface in a short period of time so that the entire substrate surface becomes compatible with the chemical solution. It turns out that it has significance.

  Furthermore, in Comparative Example 3, since the liquid process is formed on the substrate surface by performing the first process and the second process, the etching process is performed without replenishing the chemical solution. It was confirmed that the problem remained on the substrate surface and etching did not proceed with time. The graph of FIG. 4 shows this qualitatively. On the other hand, since the fresh chemical solution is replenished with respect to the liquid deposit in the embodiment, the etching process is performed with the fresh chemical solution that is replenished one after another while removing the etching reaction product from the substrate surface. As shown in Table 1, the etching rate can be kept constant and the process can be performed with excellent uniformity as shown in Table 1.

  This invention is applied to all substrates including semiconductor wafers, glass substrates for photomasks, glass substrates for liquid crystal displays, glass substrates for plasma displays, FED substrates, optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, etc. The present invention can be applied to a substrate processing method for processing a substrate by supplying a liquid.

It is a figure which shows an example of the substrate processing apparatus suitable for execution of the substrate processing method concerning this invention. It is a figure which shows one Embodiment of the substrate processing method concerning this invention. It is a figure which shows other embodiment of the substrate processing method concerning this invention. It is a graph which shows an etching characteristic.

Explanation of symbols

4, 4A, 4B ... Chemical liquid discharge nozzle 6 ... Rotating spindle 8 ... Chuck rotating mechanism 12 ... Spin base 20 ... Chemical liquid supply unit 22 ... Nozzle moving mechanism 27 ... Hydrofluoric acid liquid film 28 ... Liquid pile Wf ... Substrate surface W ... Substrate

Claims (6)

A substrate processing method for processing the substrate with the processing liquid while supplying the processing liquid toward the surface of the substrate,
A first step of supplying the processing liquid at a first flow rate to the central portion of the surface of the substrate rotating at a first rotational speed to spread the processing liquid over the entire substrate surface;
After the first step, a second step of reducing the rotation speed of the substrate to a second rotation speed that is slower than the first rotation speed to form a liquid volume of the processing liquid on the substrate surface;
A substrate processing method comprising: a third step of reducing the flow rate of the processing liquid to a second flow rate lower than the first flow rate while maintaining a liquid accumulation state after the second step.   The substrate processing method according to claim 1, wherein an execution time of the first step is shorter than an execution time of the second step.   The substrate processing according to claim 1, wherein a total amount of the processing liquid supplied to the substrate surface in the third step is smaller than a total amount of the processing liquid supplied to the substrate surface in the first step and the second step. Method.   The substrate processing method according to claim 1, wherein the third step is a step of displacing the supply position of the processing liquid with time.   5. The substrate processing method according to claim 4, wherein the third step is a step of displacing a supply position of the processing liquid from a central portion of the surface of the substrate to a peripheral portion of the surface.   The substrate processing method according to claim 1, wherein the processing liquid is an etching liquid.

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