Single wafer cleaning device and wafer surface roughness control method using the same

Abstract

The present invention provides a single-wafer cleaning apparatus and a method for controlling surface roughness of a single-wafer wafer, which can perform different cleaning processes on both sides of a wafer during the cleaning process of the wafer and can vary the roughness of both sides by using different chemicals depending on the wafer side to be cleaned. The single-wafer cleaning apparatus includes a spin chamber, a first chemical supply device, a second chemical supply device, and a third chemical supply device.

Description

[Technical field]

[0001] The present invention relates to a wafer cleaning apparatus, and more particularly to a single-wafer cleaning apparatus and a single-wafer surface roughness control method that can differentiate the roughness of the front surface and the back surface of the wafer. [Background technology]

[0002] The technologies for cleaning the surface of a semiconductor wafer can be roughly divided into wet and dry types. The surface of a semiconductor wafer undergoing a manufacturing process is covered with impurities such as slurry or particles. The cleaning process is similar to the etching process in that it removes materials from the surface of the semiconductor wafer, but it is different in that it removes impurities.

[0003] The wet process can be further divided into a batch method and a spray method.

[0004] FIG. 1 illustrates an example of a conventional batch cleaning process.

[0005] Referring to FIG. 1, the batch method first removes impurities from both sides of the wafers by depositing multiple wafers in a left-side settling tank containing chemicals, and after removing impurities from both sides of the wafers using chemicals, the wafers are deposited in a right-side settling tank to further remove impurities and chemicals remaining on the wafer surfaces, thereby carrying out a cleaning process.

[0006] The spray method is a method of removing impurities by spraying liquid or gaseous chemicals onto a rotating wafer.

[0007] The batch method is advantageous for cleaning multiple wafers at once, while the spray method is advantageous for cleaning wafers one by one. Traditionally, the batch method was used more frequently than the mass immersion method, but recently, the proportion of spray methods (single wafer type, hereafter referred to as single wafer type) has been increasing due to the sophistication of fine processing and changes in the materials used.

[0008] In the semiconductor manufacturing process, impurity particles are often generated due to the back side of the wafer slipping on the stage surface while it is being placed on the process stage, causing problems with the particles being transferred to the front side of the wafer during processing.

[0009] FIG. 2 illustrates the slippage of the wafer on the stage and the particles that are generated during this process.

[0010] Referring to FIG. 2, it can be seen that impurity particles 230 are generated as the backside of the wafer 220 seated on the top of the stage 210 slides on the top surface of the stage 210, and the generated impurity particles 230 move to the top surface of the wafer 220.

[0011] As explained in FIG. 2, in order to solve problems that occur during the semiconductor manufacturing process, a method has been proposed and used in which the surface roughness of the front side and the surface roughness of the back side (u-roughness) of the wafer are made different to minimize the slippage of the wafer during the process stage.

[0012] FIG. 3 illustrates an example of a wafer with different roughness on both sides.

[0013] Referring to FIG. 3, it can be seen that the surface roughness of the front side of a wafer that is actually subjected to a semiconductor manufacturing process is different from the surface roughness of the back side of the wafer. Summary of the Invention [Problem to be solved by the invention]

[0014] The technical problem to be solved by the present invention is to provide a single wafer cleaning apparatus capable of performing different cleaning processes on both sides of a wafer during the wafer cleaning process and using different chemicals depending on the wafer side to be cleaned, thereby making it possible to vary the roughness of both sides.

[0015] Another technical problem to be solved by the present invention is to provide a method for controlling surface roughness of a single wafer, which can make the roughness of both sides of a wafer different from each other by performing different cleaning processes on both sides of the wafer during the wafer cleaning process and using different chemicals depending on the wafer side to be cleaned. [Means for solving the problem]

[0016] To achieve the above technical objective, according to one aspect of the present invention, a single-wafer cleaning apparatus supplies a first chemical substance to an upper portion of a wafer seated on an upper portion of a rotating spindle table to clean the wafer, and supplies the first chemical substance and a second chemical substance different from the first chemical substance to a lower portion of the wafer to clean the wafer, the first chemical substance being ozone water and the second chemical substance being hydrofluoric acid.

[0017] In order to achieve the above technical object, a single wafer cleaning apparatus according to another aspect of the present invention includes a spin chamber, a first chemical supply device, a second chemical supply device, and a third chemical supply device. The spin chamber incorporates a spindle table on which a wafer is seated and which rotates during a cleaning process. The first chemical supply device supplies a cleaning chemical I to the upper part of the rotating wafer while the cleaning process is being performed. The second chemical supply device supplies a cleaning chemical II to the lower part of the rotating wafer while the cleaning process is being performed. The third chemical supply device supplies a cleaning chemical III to the lower part of the rotating wafer while the cleaning process is being performed. Here, the cleaning chemical I and the cleaning chemical II are ozone water, and the cleaning chemical III is hydrofluoric acid.

[0018] In order to achieve the other technical object, a single-wafer surface roughness control method according to one aspect of the present invention includes a spindle table rotation step of rotating a spindle table on which a wafer is seated, a first chemical supply step of supplying a cleaning chemical I to an upper portion of the wafer rotating together with the spindle table, and a second and third chemical simultaneous supply step of supplying a cleaning chemical II and a cleaning chemical III to a lower portion of the wafer rotating together with the spindle table.

[0019] In order to achieve the other technical object, a single-wafer surface roughness control method according to another aspect of the present invention includes a spindle table rotating step of rotating a spindle table on which a wafer is seated, a first chemical supplying step of supplying a cleaning chemical I to an upper portion of the wafer rotating together with the spindle table, and a second and third chemical alternate supplying step of alternately supplying a cleaning chemical II and a cleaning chemical III to a lower portion of the wafer rotating together with the spindle table.

[0020] In order to achieve the other technical object, according to still another aspect of the present invention, a single-wafer surface roughness control method includes a spindle table rotation step of rotating a spindle table on which a wafer is seated, and a first to third chemical substance simultaneous supply step of supplying a first chemical substance to an upper part of the wafer rotating together with the spindle table and simultaneously supplying a second chemical substance and a third chemical substance to a lower part of the wafer. Effect of the Invention

[0021] As described above, the single wafer cleaning apparatus and single wafer surface roughness control method according to the present invention can make the back surface of the wafer rougher than the front surface of the wafer by using different cleaning chemicals for the front and back surfaces of the wafer during the wafer cleaning process, which has the advantage of minimizing problems such as the generation of impurity particles due to wafer slippage and the transfer of impurity particles to the front surface of the wafer during the wafer and semiconductor manufacturing process. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a diagram illustrating an example of a conventional batch-type cleaning process.

[0023] [Diagram 2] 1A and 1B are diagrams for explaining slippage of a wafer occurring on a stage and particles generated at this time.

[0024] [Diagram 3] FIG. 1 is a diagram illustrating an example of a wafer having two surfaces with different roughnesses.

[0025] [Figure 4] 1 is a diagram for explaining an embodiment of a single wafer cleaning apparatus according to the present invention;

[0026] [Diagram 5] 1A to 1C are diagrams showing an embodiment of a single-wafer surface roughness control method according to the present invention.

[0027] [Figure 6] 6 is a diagram for explaining an example of the time, concentration, and flow rate of a chemical substance supplied and the rotation speed of a spindle table in the embodiment of the single-wafer surface roughness control method shown in FIG. 5.

[0028] [Figure 7] FIG. 11 is a diagram showing another embodiment of the single-wafer surface roughness control method according to the present invention.

[0029] [Figure 8] 8 is a diagram for explaining an example of the time, concentration, and flow rate of a chemical substance supplied and the rotation speed of a spindle table in another embodiment of the single-wafer surface roughness control method shown in FIG. 7.

[0030] [Figure 9] FIG. 11 is a diagram showing yet another embodiment of the single-wafer surface roughness control method according to the present invention.

[0031] [Figure 10] 10 is a diagram for explaining an example of the time, concentration, and flow rate of chemicals supplied and the rotation speed of the spindle table in still another embodiment of the single-wafer surface roughness control method shown in FIG. 9.

[0032] [Figure 11] FIG. 13 shows the degree of roughness on both sides of a wafer when the top and bottom of the wafer are cleaned simultaneously or at different times. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] For a fuller understanding of the invention, its operating advantages, and the objects attained by its practice, reference should be made to the accompanying drawings which illustrate an illustrative embodiment of the invention and the contents thereof which are set forth in the accompanying drawings.

[0034] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below by describing preferred embodiments thereof with reference to the accompanying drawings, in which the same reference numerals as used in the drawings denote the same elements.

[0035] The core idea of ​​the present invention is to selectively control the surface roughness of the upper (or front) and lower (or back) sides of the wafer by cleaning the upper and lower sides of the wafer at different times and by using different cleaning agents for the upper and lower sides of the wafer when cleaning the wafer. Through this process, the surface roughness of the lower side of the wafer will be higher than that of the upper side.

[0036] For example, the surface roughness of the top of the wafer is controlled using a first chemical, i.e., ozone water (O3), and the surface roughness of the bottom of the wafer is controlled using both the first chemical and a second chemical, i.e., hydrofluoric acid (HF).

[0037] After cleaning the top and bottom of a wafer using the method proposed in this invention, the experimental results showed that the surface roughness per 1 μm×1 μm of the top of the wafer, which was cleaned using ozone water, was 0.9 Å to 1.0 Å, while the surface roughness of the bottom of the wafer, which was cleaned using ozone water and hydrofluoric acid, was 1.5 Å or more.

[0038] In particular, when comparing the case where ozone water and hydrofluoric acid are simultaneously supplied to the bottom of the wafer with the case where ozone water and hydrofluoric acid are supplied at different times, the experimental result showed that the surface roughness of the bottom of the wafer when ozone water and hydrofluoric acid are simultaneously supplied is rougher than when ozone water and hydrofluoric acid are supplied alternately (alternate supply).

[0039] In addition, when ozone water and hydrofluoric acid are alternately introduced, it is possible to carry out the cleaning process of the upper part of the wafer and the cleaning process of the lower part of the wafer separately, and it is also possible to introduce ozone water into the upper part and the lower part of the wafer at the same time, and introduce hydrofluoric acid into only the lower part of the wafer.

[0040] As a result of the experiment, it was confirmed that the surface roughness of the top of the wafer produced by the above method was 0.9 Å to 1.0 Å, and therefore the thickness of the pad can be adjusted during the pad process.

[0041] The following explanation is based on the experimental results described above.

[0042] FIG. 4 illustrates an embodiment of a single wafer cleaning apparatus according to the present invention.

[0043] Referring to FIG. 4, a single wafer cleaning apparatus 400 according to the present invention includes a spin chamber 410, a spindle table 420, a first chemical supply device 430, a second chemical supply device 440, and a third chemical supply device 450.

[0044] The spin chamber 410 incorporates a spindle table 420 on which the wafer 460 sits and which rotates during the cleaning process. The spin chamber 410 maintains a vacuum state inside during the cleaning process. The first chemical supply device 430 supplies cleaning chemical I to the top of the rotating wafer 460 while the cleaning process is being performed. The second chemical supply device 440 supplies cleaning chemical II to the bottom of the rotating wafer 460 while the cleaning process is being performed. The third chemical supply device 450 supplies cleaning chemical III to the bottom of the rotating wafer 460 while the cleaning process is being performed.

[0045] In some embodiments, the supply of cleaning chemistry I and the supply of cleaning chemistry II and cleaning chemistry III may occur at different times, although in other embodiments they may be supplied simultaneously.

[0046] In the present invention, it is proposed to use ozone (O3) or ozone water as cleaning chemical I and cleaning chemical II, and hydrofluoric acid (HF) as cleaning chemical III.

[0047] FIG. 5 shows an embodiment of a method for controlling surface roughness of a single wafer according to the present invention.

[0048] Referring to FIG. 5, a method 500 for controlling surface roughness of a single wafer according to the present invention includes a spindle table rotating step 510, a first chemical supplying step 520, and a second and third chemical supplying step 530.

[0049] In step 510 of rotating the spindle table, the spindle table on which the wafer is seated is rotated.

[0050] In the first chemical supply step 520, a first chemical, i.e., de-ionized ozone water, which is chemical I, is supplied to the upper part of the wafer rotating together with the spindle table. At this time, no cleaning chemical is supplied to the lower part of the wafer.

[0051] In the step of simultaneously supplying the second and third chemicals 530, the second and third chemicals, i.e., the second chemicals, cleaning chemical II and cleaning chemical III, are supplied to the bottom of the wafer rotating together with the spindle table. As described above, cleaning chemical II and cleaning chemical III are ozone water and hydrofluoric acid. At this time, no cleaning chemical is supplied to the top of the wafer.

[0052] It does not matter which step of supplying the first chemical substance 520 and the second and third chemical substances 530 is performed first, but when cleaning one side (e.g., the top) of the wafer, the cleaning process should not be performed on the opposite side (e.g., the bottom) of the wafer.

[0053] However, in order to maximize the cleaning effect, it is suggested that the steps of rotating the spindle table 510, supplying the first chemical substance 520, and simultaneously supplying the second and third chemical substances 530 be repeated at least 12 times and up to 18 times.

[0054] FIG. 6 illustrates an example of the time, concentration, and flow rate of the chemicals supplied and the rotation speed of the spindle table in one embodiment of the single-wafer surface roughness control method shown in FIG.

[0055] 6, in the first chemical supply step 520, ozone water in an amount of 0.5-1.5 lpm (liters per minute) having a concentration of 5-20 ppm (parts per million) is supplied for 1-5 seconds to the upper part of the wafer rotating at a speed of 500-1,500 rpm (revolutions per minute) (left part of FIG. 6), and in the second and third chemical supply steps 530, ozone water in an amount of 0.5-1.5 lpm having a concentration of 5-20 ppm and hydrofluoric acid in an amount of 0.5-1.5 lpm having a concentration of 0.2-1.0 wt% are supplied for 1-5 seconds to the lower part of the wafer rotating at a speed of 500-1,500 rpm (right part of FIG. 6).

[0056] As mentioned above, it is preferred to perform the process of alternately cleaning the top and bottom of the wafer at least 12 times and up to 18 times.

[0057] FIG. 7 shows another embodiment of the method for controlling surface roughness of a single wafer according to the present invention.

[0058] Referring to FIG. 7, a method 700 for controlling surface roughness of a single wafer according to the present invention includes a spindle table rotating step 710, a first chemical supplying step 720, and an alternate supplying step 730 of second and third chemicals.

[0059] In step 710 of rotating the spindle table, the spindle table with the wafer seated thereon is rotated. In step 720 of supplying a first chemical, a first chemical is supplied to an upper portion of the wafer rotating together with the spindle table. In step 730 of supplying second and third chemicals alternately, a second chemical and a third chemical are alternately supplied to a lower portion of the wafer rotating together with the spindle table.

[0060] The single-wafer surface roughness control method 700 shown in FIG. 7 is the same as the single-wafer surface roughness control method 500 shown in FIG. 5 in that cleaning of the upper and lower surfaces of the wafer is performed at different times. However, the single-wafer surface roughness control method 700 differs from the single-wafer surface roughness control method 500 shown in FIG. 5 in that when cleaning the lower surface of the wafer, the second and third chemicals are not added simultaneously but are added alternately.

[0061] FIG. 8 illustrates an example of the time, concentration, and flow rate of the chemicals supplied and the rotation speed of the spindle table in another embodiment of the single-wafer surface roughness control method shown in FIG.

[0062] 8, in the first chemical supply step 720, ozone water having a concentration of 5-20 ppm is supplied for 1-5 seconds at 0.5-1.5 lpm to the top of the wafer rotating at a speed of 500-1,500 rpm (left part of FIG. 8). In the second and third chemical alternate supply step 730, ozone water having a concentration of 5-20 ppm at 0.5-1.5 lpm and hydrofluoric acid having a concentration of 0.2-1.0 wt% at 0.5-1.5 lpm are supplied for 1-5 seconds to the bottom of the wafer rotating at a speed of 500-1,500 rpm (right part of FIG. 8).

[0063] It is preferred that the process of alternately cleaning the top and bottom of the wafer is performed at least 12 times and up to 18 times.

[0064] The embodiment shown in FIG. 7 is the same as the embodiment shown in FIG. 5 in that the time for cleaning the upper part of the wafer is different from the time for cleaning the lower part of the wafer. However, it differs from the embodiment shown in FIG. 5 in that when cleaning the lower part, the second and third chemicals are not used simultaneously but are used alternately.

[0065] FIG. 9 shows yet another embodiment of the method for controlling surface roughness of a single wafer according to the present invention.

[0066] Referring to FIG. 9, a method 900 for controlling surface roughness of a single wafer according to the present invention includes a step 910 of rotating a spindle table and a step 920 of simultaneously supplying first, second and third chemical substances.

[0067] In step 910 of rotating the spindle table, the spindle table on which the wafer is seated is rotated.

[0068] In the first to third chemical substance simultaneous supply step 920, the first chemical substance is supplied to the upper part of the wafer rotating together with the spindle table, while the second and third chemical substances are simultaneously supplied to the lower part of the wafer.

[0069] FIG. 10 illustrates an example of the time, concentration, and flow rate of the chemicals supplied and the rotation speed of the spindle table in yet another embodiment of the single-wafer surface roughness control method shown in FIG.

[0070] Referring to FIG. 10, in the first to third chemical substance simultaneous supply step 920, ozone water having a concentration of 5 to 20 ppm is supplied for 6 to 120 seconds at a rate of 0.5 to 1.5 lpm onto the wafer rotating at a speed of 500 to 1,500 rpm.

[0071] It can be seen that the embodiment of FIG. 9 differs from the embodiments shown in FIGS. 5 and 7 in that a single cleaning operation lasts from 6 to 120 seconds.

[0072] FIG. 11 shows the degree of roughness on both sides of a wafer when the top and bottom of the wafer are cleaned simultaneously or at different times.

[0073] FIG. 11 shows the results of carrying out the embodiment shown in FIGS. 5 to 7, and shows measurements of the roughness at the center and at a point a certain distance away from the center on the front side and back side of the wafer.

[0074] The roughness of the front surface of the wafer is the same at about 0.9 Å (Angstrom), but it can be seen that the roughness of the back surface of the wafer is about 0.9 Å rougher in the simultaneous supply example than in the alternate supply example.

[0075] The surface roughness of the back side of the wafer by the alternate supply shown on the left side of FIG. 11 is 1.5 Å at the center, and the roughness at points 50 mm, 100 mm, and 140 mm away from the center is 1.6 Å, 1.7 Å, and 1.6 Å, respectively, which shows that all of the roughnesses are 1.5 Å or more.

[0076] The surface roughness of the back surface of the wafer obtained by simultaneous supply, shown on the right side of Figure 11, is 2.4 Å at the center, and the roughness at points 50 mm, 100 mm, and 140 mm away from the center is 2.5 Å, 2.6 Å, and 2.5 Å, respectively, which shows that all of the roughnesses are 2.4 Å or greater.

[0077] Comparing the left side (an example of alternating supply) and the right side (an example of simultaneous supply) of FIG. 11, it can be seen that when the second and third chemicals, ozone and hydrofluoric acid, are supplied simultaneously to the bottom of the wafer, the backside of the wafer is rougher than the frontside of the wafer than when they are supplied alternately.

[0078] In conclusion, whether cleaning is performed in an alternating supply manner or in a simultaneous supply manner according to the present invention, it can be seen that when different cleaning chemicals are used on the front and back surfaces of the wafer, the back surface of the wafer is rougher than the front surface of the wafer.

[0079] Therefore, by cleaning the front and back surfaces of the wafer in the manner according to the present invention, the back surface of the wafer can be made rougher than the front surface of the wafer, minimizing slippage of the wafer when it is seated on a stage in a subsequent process, thereby minimizing the generation of impurity particles due to wafer slippage as in the conventional case.

[0080] Conventionally, the batch cleaning method, which has been used frequently, has been limited to making the roughness of the front and back surfaces of the wafer the same, and it is not easy to control the degree of roughness. [Industrial Applicability]

[0081] The present invention relates to a wafer cleaning apparatus, which can solve the problem of impurity particles transferring to the front surface of a wafer during the wafer manufacturing process, thereby improving the manufacturing yield of the semiconductor industry.

Claims

1. A method of cleaning a wafer comprising: a spin chamber having a spindle table on which a wafer sits and which rotates during the cleaning process; a first chemical supply device for supplying a cleaning chemical I onto the top of the rotating wafer while a cleaning process is being performed; a second chemical supply device that supplies cleaning chemical II to the bottom of the rotating wafer while a cleaning process is being performed; a third chemical supply device for supplying a cleaning chemical III to the bottom of the rotating wafer while a cleaning process is being performed; The cleaning chemical I and the cleaning chemical II are ozone water, and the cleaning chemical III is hydrofluoric acid; the second chemical supply device and the third chemical supply device do not supply the cleaning chemical II and the cleaning chemical III to the lower part of the wafer while the first chemical supply device supplies the cleaning chemical I to the upper part of the wafer; the first chemical supply device does not supply the cleaning chemical I to the top of the wafer while the second chemical supply device and the third chemical supply device are supplying the cleaning chemical II and the cleaning chemical III to the bottom of the wafer.

2. A single-wafer cleaning apparatus as described in claim 1, wherein when the second chemical supply device and the third chemical supply device supply the cleaning chemical II and the cleaning chemical III to the underside of the wafer, the cleaning chemical II and the cleaning chemical III are supplied to the underside of the wafer simultaneously.

3. A single-wafer cleaning apparatus as described in claim 1, wherein when the second chemical supply device and the third chemical supply device supply the cleaning chemical II and the cleaning chemical III to the underside of the wafer, the cleaning chemical II and the cleaning chemical III are alternately supplied to the underside of the wafer.

4. A spin chamber having a built-in spindle table on which a wafer sits and which rotates during a cleaning process; a first chemical supply device for supplying a cleaning chemical I onto the top of the rotating wafer while a cleaning process is being performed; a second chemical supply device that supplies cleaning chemical II to the bottom of the rotating wafer while a cleaning process is being performed; a third chemical supply device for supplying a cleaning chemical III to the bottom of the rotating wafer while a cleaning process is being performed; The cleaning chemical I and the cleaning chemical II are ozone water, and the cleaning chemical III is hydrofluoric acid; A single wafer cleaning apparatus that supplies the cleaning chemical I to the top of the wafer while simultaneously supplying the cleaning chemical II and the cleaning chemical III to the bottom of the wafer.

5. A spindle table rotating step of rotating a spindle table on which a wafer is seated; a first chemical supply step of supplying a cleaning chemical I onto the wafer rotating with the spindle table; and a second and third chemical simultaneous supply step of supplying cleaning chemicals II and III to the bottom of the wafer rotating with the spindle table; The method for controlling surface roughness of a single wafer, wherein the spindle table rotating step, the first chemical substance supplying step, and the second and third chemical substance simultaneous supplying steps are repeated at least 12 times to at most 18 times.

6. In the first chemical supply step, ozone water having a concentration of 5 to 20 ppm is supplied for 1 to 5 seconds in an amount of 0.5 to 1.5 lpm to an upper portion of the wafer rotating at a speed of 500 to 1,500 rpm; 6. The method of claim 5, wherein in the second and third chemical supplying steps, ozone water having a concentration of 5 to 20 ppm in an amount of 0.5 to 1.5 lpm and hydrofluoric acid having a concentration of 0.2 to 1.0 wt % in an amount of 0.5 to 1.5 lpm are supplied for 1 to 5 seconds under the wafer rotating at a speed of 500 to 1,500 rpm.

7. A spindle table rotating step of rotating a spindle table on which a wafer is seated; a first chemical supply step of supplying a cleaning chemical I onto the wafer rotating with the spindle table; and a second and third chemical alternate supply step of alternately supplying cleaning chemicals II and III to the bottom of the wafer rotating with the spindle table; The method for controlling surface roughness of a single wafer, wherein the spindle table rotating step, the first chemical supplying step, and the second and third chemical supplying steps are repeated at least 12 times to at most 18 times.

8. In the first chemical supply step, ozone water having a concentration of 5 to 20 ppm is supplied for 1 to 5 seconds at an amount of 0.5 to 1.5 lpm to an upper portion of the wafer rotating at a speed of 500 to 1,500 rpm; 8. The method of claim 7, wherein in the second and third chemical supplying steps, ozone water having a concentration of 5 to 20 ppm in an amount of 0.5 to 1.5 lpm and hydrofluoric acid having a concentration of 0.2 to 1.0 wt % in an amount of 0.5 to 1.5 lpm are supplied for 1 to 5 seconds under the wafer rotating at a speed of 500 to 1,500 rpm.

9. A spindle table rotating step of rotating a spindle table on which a wafer is seated; and a simultaneous supplying step of first to third chemical substances of supplying a first chemical substance to an upper portion of the wafer rotating together with the spindle table and simultaneously supplying a second chemical substance and a third chemical substance to a lower portion of the wafer.

10. A single-wafer surface roughness control method as described in claim 9, wherein, in the first to third chemical substance simultaneous supply step, ozone water in an amount of 0.5 to 1.5 lpm having a concentration of 5 to 20 ppm is supplied for 6 to 120 seconds to the upper part of the wafer rotating at a speed of 500 to 1,500 rpm, and at the same time, ozone water in an amount of 0.5 to 1.5 lpm having a concentration of 5 to 20 ppm and hydrofluoric acid in an amount of 0.5 to 1.5 lpm having a concentration of 0.2 to 1.0 wt % are supplied for 6 to 120 seconds to the lower part of the wafer.

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