KR100828120B1 - Method of cleaning a substrate - Google Patents

Abstract

A method for cleaning a substrate is provided to decrease a process time by moving a spray unit for spraying chemicals on the substrate to a region close to a center portion of the substrate. A substrate is divided into a first region including an edge portion and a second region including a region adjacent to a center thereof. The substrate is rotated(S100). A cleaning solution is sprayed on the substrate to remove pollutants from the substrate(S200). Deionized water is sprayed on the substrate to rinse off the cleaning solution. A spray unit for spraying chemicals moves to a predetermined position in the second region(S300). While the spray unit moves from the predetermined position to an edge region of the first region through the center of the substrate, at least one of a rotation speed of the substrate, a moving speed of the spray unit, and the spray time is variably changed during a chemical spraying process(S400).

Description

Substrate Cleaning Method {METHOD OF CLEANING A SUBSTRATE}

1 is a flowchart illustrating a substrate cleaning method according to embodiments of the present invention.

2 to 8 are plan views illustrating the operation of the substrate cleaning apparatus according to the substrate cleaning method of FIG. 1.

FIG. 9 is a perspective view illustrating the third injection unit of FIGS. 2 to 8.

<Description of the symbols for the main parts of the drawings>

1000 substrate cleaning apparatus 100 first injection unit

200: second injection unit 300: third injection unit

310: chemical injection unit 320: dry gas injection unit

R1, R2, R3, R4: Rotational Speed M1, M2, M3: Movement Speed

The present invention relates to a substrate cleaning method, and more particularly, to a substrate cleaning method for removing impurities remaining on the substrate.

In general, the manufacturing process of an integrated circuit device such as a semiconductor device is a cleaning process that removes not only particles generated during the process but also impurities generated by various contaminants such as contamination from equipment, contamination by reactants or products during the process. Include. In particular, as the integrated circuits become smaller and the devices are highly integrated, even very small pollutants, such as 0.1 µm, which were not considered important in the past, have a great effect on the performance of the product. Doing.

Therefore, the cleaning process is performed in the pre- and / or post-step of each process in order to keep the surface of the substrate undergoing a plurality of processes clean. In order to complete the integrated circuit device, the cleaning process is repeatedly performed, and the cleaning process occupies about 30 to 40 percent of the entire manufacturing process. In addition, as the design rule becomes smaller, the ratio of the cleaning process to the overall process is increasing.

Meanwhile, the cleaning apparatus used in the cleaning process injects chemicals having a low surface tension to remove impurities remaining on the substrate and to dry the chemicals by spraying dry gas to remove the used chemicals.

At this time, the cleaning device sprays chemical and dry gas while moving at a constant speed on the substrate. The substrate is then rotated at a constant speed so that the injected chemical and dry gas are provided to the entire substrate. Therefore, when the substrate is rotated at a uniform speed irrespective of the region on the substrate and the chemicals and dry gas are injected while the cleaning apparatus is moved at a uniform speed, the cleaning efficiency is different for each region on the substrate.

An object of the present invention is to provide a substrate cleaning method for efficiently removing impurities remaining on a substrate.

In the substrate cleaning method according to the embodiments of the present invention for achieving the above object, first, a substrate divided into a first section including the edge and a second section including a portion adjacent to the center portion is rotated. The cleaning solution is sprayed onto the substrate to remove impurities remaining on the substrate. Subsequently, deionized water is sprayed onto the substrate to rinse the cleaning liquid, and at the same time, a spray unit for spraying chemical onto the substrate is moved to a predetermined point of the second section. The rotational speed of the substrate, the moving speed of the jetting part, and the jetting time of the jetting part are moved for each of the sections when the jetting part is moved from a predetermined point of the second section to the edge of the first section past the center of the substrate. Chemically is sprayed onto the substrate through the sprayer while varying at least one of the impurities to remove the impurities and the remaining cleaning liquid.

According to an embodiment of the present disclosure, the removing of the impurities and the remaining cleaning liquid may include: forming a first injection portion between the jetting portion and a first position located inside the edge of the first portion; Spraying the chemical onto the substrate rotating at a first rotational speed while repeatedly moving at a moving speed, and the spraying portion is moved from a predetermined point of the second section to a second position located between the central portion of the substrate and the first position Injecting a dry gas for drying the chemical and the chemical onto the substrate while moving at a second movement speed lower than the first movement speed, wherein the injection portion is moved from the second position to the first position direction; Injecting the chemical and the dry gas onto the substrate while moving at a third movement speed lower than the movement speed, and And a substrate spinning at a higher second rotational speed greater than the first rotation speed from the second position to the ejection portion groups the edge direction of the first section comprises the step of injecting the chemicals and the drying gas.

According to an embodiment of the present invention, the spraying part stops at a predetermined point of the second section for a predetermined time in the step of spraying the chemical while moving between the predetermined point and the first position of the second section. The chemicals may be sprayed to remove impurities remaining in the center portion of the substrate. At this time, the predetermined time may be about 1/60 to 80/1 of the total time required for the step of injecting the chemical while moving between the injection point and the first position of the second section. Can be.

According to an embodiment of the present invention, in the step of injecting the chemical and the dry gas while the injector moves in the edge direction of the first section from the second position, the injector is the edge of the first section It is possible to remove impurities remaining at the edge of the substrate by spraying the chemical and the drying gas by stopping for a predetermined time. In this case, the predetermined time may be four to six times the total time required for the step of injecting the chemical and the dry gas while the injection unit moves in the edge direction of the first section from the second position. .

According to an embodiment of the present invention, the jetting part injects onto the substrate using a material having a lower surface tension than the cleaning liquid as the chemical.

According to an embodiment of the present invention, the injection unit injects the chemical and the dry gas at different angles.

According to an embodiment of the present invention, after spraying the chemical and the dry gas on the substrate to rotate at the second rotational speed, the dry gas to the substrate to rotate at a third rotational speed higher than the second rotational speed And spraying the washing solution and the chemical.

In the substrate cleaning method according to the embodiment of the present invention, by dividing the substrate into sections and changing the conditions of the cleaning process for each section, impurities remaining in the substrate and the remaining cleaning liquid can be efficiently removed.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the drawings, similar reference numerals are used for similar components. In the accompanying drawings, the dimensions of the structures are shown in an enlarged scale than actual for clarity of the invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described in the specification, and that one or more other features It should be understood that it does not exclude in advance the possibility of the presence or addition of numbers, steps, actions, components, parts or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

1 is a flowchart illustrating a substrate cleaning method according to embodiments of the present invention.

Referring to FIG. 1, in a substrate cleaning method according to embodiments of the present invention, a substrate divided into a first section including an edge of a substrate and a second section including a portion adjacent to a central portion of the substrate are rotated ( S100). The cleaning solution is sprayed onto the substrate to remove impurities remaining on the substrate (S200). Then, deionized water is sprayed onto the substrate to rinse the cleaning liquid and simultaneously move the spray unit for spraying the chemical onto the substrate to a predetermined point of the second section (S300). Subsequently, when the spraying unit is moved from the predetermined point of the second section to the edge of the first section beyond the center of the substrate, at least one of the rotational speed of the substrate and the moving speed of the spraying unit is variably changed for each section. Chemical injection (S400).

As such, while performing the rinse process, the spray unit is moved to a predetermined point of the second section of the substrate. The substrate is divided into predetermined sections, and the rotational speed of the substrate, the moving speed of the injection unit, and / or the injection time are variably changed for each section. Therefore, the injection unit can efficiently remove impurities remaining on the substrate corresponding to the region of the section.

Hereinafter, a substrate cleaning method according to embodiments of the present invention will be described in detail.

2 to 8 are plan views illustrating the operation of the substrate cleaning apparatus according to the substrate cleaning method of FIG. 1.

2 to 8, the substrate cleaning apparatus 1000 includes a first spraying unit 100, a second spraying unit 200, and a third spraying unit 300.

The first injection unit 100 injects deionized water and / or dry gas to the rotating substrate W. In embodiments of the present invention, the first injection unit 100 is fixedly disposed outside the chamber (not shown). In other embodiments of the present invention, the first injection unit 100 may move to spray deionized water and / or dry gas.

The second spray unit 200 sprays the cleaning liquid onto the rotating substrate W. As shown in FIG. In embodiments of the present invention, the second injection unit 200 is disposed outside the chamber, and sprays the cleaning liquid while moving in a predetermined direction. For example, the second injection unit 200 may move linearly in the left and right directions. Alternatively, the second injection unit 200 may spray the cleaning liquid while moving while drawing various trajectories.

The third injection unit 300 injects chemical and dry gas to the rotating substrate (W). In embodiments of the present invention, the third injection unit 300 is disposed outside the chamber, and injects chemical and dry gas while moving in a predetermined direction. For example, the third injection unit 300 may move while having a curved trajectory. Alternatively, the third injection unit 300 may inject chemical and dry gas while linearly moving the linear trajectory.

According to an embodiment of the present invention, the substrate W is partitioned into a predetermined section. For example, the substrate W may be divided into a first section including an edge and a second section including a portion adjacent to the central portion C of the substrate W. For example, as illustrated in FIG. In this way, the substrate W partitioned in a predetermined section is rotated at a set rotation speed. Herein, although the claims are described as dividing the substrate W into two sections, the first section and the second section, it will be apparent to those skilled in the art that the substrate W may be divided into n sections (n is a natural number of 3 or more). I will say. Hereinafter, the substrate W is divided into a plurality of sections based on the movement path of the third injection unit 300 to variably change the rotational speed of the substrate W, the movement speed of the third injection unit 300, or the injection speed. It will be described as changing.

Although not shown, deionized water is sprayed onto the substrate W having a series of processes completed. Therefore, the substrate W can be kept in a wet state by spraying deionized water onto the substrate W at the initial stage of the cleaning process using the cleaning liquid and / or chemicals. On the other hand, the substrate W is rotated at a constant first rotational speed R1 in order to distribute the injected deionized water uniformly throughout the substrate W. FIG. For example, the first rotational speed R1 may be 400 RPM (revolution per minute) to 600 RPM. For example, when the first rotational speed R1 exceeds 600 RPM, deionized water may be scattered out of the substrate W by centrifugal force generated by the rotation of the substrate W. In addition, when the first rotational speed R1 is less than 400 RPM, deionized water may not be uniformly distributed throughout the substrate W. FIG. Therefore, it is preferable that the 1st rotational speed R1 of the board | substrate W becomes 500 RPM.

Referring to FIG. 2, the first spraying unit 100 sprays the cleaning liquid onto the substrate W to which deionized water is sprayed. The cleaning liquid contains, for example, hydrogen fluoride. In contrast, the cleaning liquid may include various materials as long as the impurities remaining in the substrate W may be removed. In embodiments of the present invention, the first injection unit 100 is linearly moved from a position spaced apart from the substrate W and is positioned in a predetermined area on the substrate W. FIG. In addition, the first spraying unit 100 sprays the cleaning liquid for a period of 60 seconds to remove impurities remaining on the substrate W. On the other hand, as in the case of deionized water, when the cleaning liquid is injected, the substrate W rotates at the first rotational speed R1 of 400 to 600 RPM. Therefore, since the first spraying unit 100 sprays the cleaning liquid onto the substrate W for a relatively long time and the substrate W rotates at the first rotational speed R1, the cleaning liquid is uniformly spread over the entire substrate W. FIG. Impurities can be efficiently removed. As mentioned, it will be said that the substrate W is preferably rotated at a first rotational speed R1 of 500 RPM.

Referring to FIG. 3, a rinse process for rinsing the cleaning liquid is performed to sufficiently remove the cleaning liquid from the substrate W. Referring to FIG. In embodiments of the present invention, the deionized water is sprayed on the substrate W to which the second spray unit 200 rotates. Here, the substrate W rotates at a first rotational speed R1 of 400 RPM to 600 RPM. Accordingly, deionized water may be uniformly provided to the entire substrate W rotating at the first rotational speed R1. Therefore, deionized water may be sprayed onto the substrate W on which the second spray unit 200 rotates to wash off the cleaning liquid remaining on the substrate W. FIG.

In embodiments of the present invention, when the second injection unit 200 injects deionized water, the third injection unit 300 for injecting the chemical and / or dry gas to a point adjacent to the central portion (C) Move it. That is, while spraying deionized water, the third spraying unit 300 is positioned adjacent to the central portion C of the substrate W. In embodiments of the present invention, the third spray unit 300 is moved from the edge of the substrate W in the direction of the center portion C. For example, the third injection unit 300 moves while drawing a curve trajectory. In particular, the third spray unit 300 is positioned at the first position P1 adjacent to the central portion C of the substrate W and opposite to the edge. For example, the first position P1 becomes a predetermined point of the second section described in the claims. Here, positioning the third injection unit 300 past the central portion C of the substrate W may include a chemical injection unit (not shown) and a dry gas injection unit (not shown) included in the third injection unit 300. Not inclined at an angle from the surface of the substrate W to inject chemical and dry gas. That is, the third injection unit 300 is positioned at the first position P1 after passing through the central portion C of the substrate W in consideration of the injection angles of the chemical injection portion and the dry gas injection rain. Therefore, the third injection unit 300 is provided in a state for injecting the chemical and / or dry gas.

As described above, the second spraying unit 200 sprays the deionized water onto the substrate W and simultaneously moves the third spraying unit 300 to the first position P1. Therefore, by omitting an additional step of moving the third injection unit 300, the process time may be shortened to improve overall process efficiency.

Hereinafter, a division between the first position P1 and the second position P2 corresponding to the edge of the substrate W is divided into at least one or more sections, and the rotational speed and / or the third speed of the substrate W is divided into sections. Chemical and / or dry gas is injected onto the substrate W while changing the moving speed of the injection unit 300. For example, the chemical consists of a material having a lower surface tension than the cleaning liquid. This is to easily remove the cleaning liquid having a relatively high surface tension from the substrate (W). In embodiments of the present invention, the chemical may be IPA (Isopropyl Alcohol). In addition, the dry gas may include N2.

Referring to FIG. 4, first, the third spray unit 300 sprays the chemical while repeatedly moving between the first position P1 and the third position P3 adjacent to the edge of the substrate W. FIG. For example, the third spraying unit 300 may spray the chemical while repeatedly moving the section at least two times. At this time, the substrate W is rotated at a second rotational speed R2 of 250 RPM to 350 RPM. Then, the third injection unit 300 injects the chemical for a time of about 6 to 8 seconds. In addition, the third injection unit 300 moves in the section at a first moving speed M1 of 100 mm / s. Therefore, the third spraying unit 300 may remove impurities remaining on the substrate W by spraying the chemical while moving at a relatively fast first moving speed M1 for a relatively short time. Alternatively, the second rotational speed R2, the first moving speed M1, and / or the process time may be variously changed according to the cleaning liquid, the amount of the chemical, and / or the kind of impurities. Here, the third spraying unit 300 sprays only the chemical without a drying process in order to preferentially remove impurities and / or cleaning liquid remaining on the substrate (W).

In embodiments of the present invention, the third injection unit 300 injects the chemical in a state where it is stopped for a predetermined time at the first position (P1). For example, the third injection unit 300 injects the chemical in a state where the third injection unit 300 is stopped for about 0.1 second at the first position P1. The time of 0.1 second is about 1/80 to about one-eighth of the total time when the third injection unit 300 injects the chemical while repeatedly moving between the first position P1 and the third position P3. This is to sufficiently remove impurities remaining in the central portion C of the substrate W for a relatively short time. In contrast, the third spray unit 300 may spray the chemical for a relatively long time at the first position P1 or the central portion C of the substrate W. FIG.

Referring to FIG. 5, the third injection unit 300 injects chemical and dry gas while moving from the first position P1 to the fourth position P4. For example, the fourth position P4 is located between the central portion C of the substrate W and the third position P3. At this time, the substrate W is rotated at a second rotational speed R2 of 250 RPM to 350 RPM. Then, the third injection unit 300 injects the chemical and dry gas for a time of 20 seconds. In addition, the third injection unit 300 moves the section at a second moving speed M2 of 5 mm / s, for example. Therefore, the third spraying unit 300 moves at the second moving speed M2 for a relatively long time to remove impurities remaining on the substrate W rotating at the second rotational speed R2, and thus impurities Etc. can be removed.

Referring to FIG. 6, the third injection unit 300 injects chemical and dry gas while moving in a direction from the fourth position P4 to the third position P3. At this time, the substrate W is rotated at a second rotational speed R2 of 150 RPM to 350 RPM. Then, the third injection unit 300 injects chemical and dry gas for a time of 25 seconds. In addition, the third injection unit 300 moves, for example, the section at a third moving speed M3 of 2 mm / s. Accordingly, the third spray unit 300 may perform a relatively slow third movement speed M3 for a relatively long time in order to sufficiently remove impurities remaining on the substrate W rotating at the second rotation speed R2. To remove impurities.

Here, the section between the third position P3 and the fourth position P4 is smaller than the section between the first position P1 and the fourth position P4. Since the section between the third position P3 and the fourth position P4 corresponds to the edge of the substrate W having a circular shape, the section between the first position P1 and the fourth position P4 This is because they have a relatively large area and / or area in comparison with the other. Therefore, since the third injection unit 300 injects chemical and / or dry gas while moving at a relatively slow third moving speed M3 for a relatively long time, impurities remaining in the section can be sufficiently removed. .

Referring to FIG. 7, the third injection unit 300 injects chemical and dry gas while moving in a direction from the third position P3 to the second position P2. At this time, the substrate W is rotated at a third rotational speed R3 of 800 RPM to 1200 RPM. In addition, the third injection unit 300 injects chemical and dry gas while moving the section at a third moving speed M3 of 2 mm / s for a time of 1 second. Here, the third injection unit 300 injects the chemical and dry gas for a relatively short time, but because the substrate W rotates at a relatively high third rotational speed R3, the edge region of the substrate W Impurities remaining in the substrate W may be removed from the substrate W by centrifugal force generated by the rotation of the substrate W. FIG.

In embodiments of the present invention, the third injection unit 300 injects the chemical and dry gas in a state in which the third injection unit 300 is stopped for a predetermined time. For example, the third injection unit 300 injects the chemical and dry gas in a state where the third injection unit 300 is stopped for a time of 5 seconds at the second position P2. This is about 4 to 6 times the total time for the third injection unit 300 to spray the chemical and dry gas while moving from the third position (P3) to the second position (P2). This is to sufficiently remove impurities remaining at the edge of the substrate W for a relatively long time. In this case, when the third injection unit 300 sprays for less than four times the total time, impurities are not sufficiently removed, and if the third spray unit 300 sprays for more than six times, the overall process time may increase. Can be. However, according to the amount and type of impurities, the third injection unit 300 may inject chemical and dry gas in a state where the third injection unit 300 is stopped for various periods of time.

Referring to FIG. 8, in the embodiments of the present invention, the second spraying unit 200 further sprays the drying gas to finally dry the cleaning liquid and / or the chemical remaining on the substrate W. FIG. At this time, the substrate W rotates at the fourth rotational speed R4 at a high speed of, for example, 1500 RPM. Therefore, the 2nd injection unit 200 can spray dry gas sequentially, and can dry efficiently the washing | cleaning liquid and / or chemical which remain | survive on the board | substrate W. FIG.

In this manner, the substrate W is divided into predetermined sections, and the rotation speed of the substrate W, the moving speed of the third injection unit 300, and / or the processing time are variably changed for each of the sections. Residual impurities can be removed efficiently.

9 is a perspective view illustrating an example of the third injection unit 300 of FIGS. 2 to 8.

Referring to FIG. 9, the third injection unit 300 includes a chemical injection unit 310 for injecting chemicals and a dry gas injection unit 320 for injecting dry gas. For example, the chemical injection unit 310 and the dry gas injection unit 320 are integrally formed in the third injection unit 300.

In the embodiments of the present invention, the chemical injection unit 310 and the dry gas injection unit 320 injects the chemical and dry gas at different angles. Specifically, since the third injection unit 300 moves a predetermined section on the substrate W, the chemical injection unit 310 and the dry gas injection unit 320 fixed to the third injection unit 300 also move while the chemical And spray dry gas. Therefore, since the chemical injection unit 310 moves while injecting the chemical, the dry gas injection unit 320 may inject dry gas at a different angle from the chemical injection unit 310 to sufficiently dry the injected chemical. Therefore, the chemical injected from the chemical injection unit 310 can be efficiently removed by the dry gas injected from the dry gas injection unit 320 at a different angle from the chemical injection angle.

As such, the chemical injection unit 310 and the dry gas injection unit 320 of the third injection unit 300 may efficiently dry the injected chemical by injecting the chemical and the dry gas at different angles. Thus, the efficiency of the overall cleaning process is improved.

According to the present invention, the spraying unit for rinsing the cleaning liquid provided on the substrate while simultaneously spraying the chemical on the substrate is moved to an area adjacent to the center of the substrate. Therefore, it is possible to reduce the process time by omitting a separate step to improve the overall process efficiency.

In addition, in order to remove impurities remaining on the substrate, the substrate is divided into predetermined sections, and cleaning conditions are different for each section. Therefore, impurities and residues remaining on the substrate can be efficiently removed and dried.

As described above, although described with reference to preferred embodiments of the present invention, those skilled in the art will be variously modified without departing from the spirit and scope of the invention described in the claims below. And can be changed.

Claims (9)

Rotating the substrate divided into a first section including an edge and a second section including a portion adjacent to the center portion; Spraying a cleaning solution onto the substrate to remove impurities remaining on the substrate; Spraying deionized water onto the substrate to rinse the cleaning liquid and simultaneously move a spraying unit for spraying chemical onto the substrate to a predetermined point of the second section; And When the sprayer is moved from the predetermined point of the second section to the edge of the first section beyond the center of the substrate, the rotation speed of the substrate, the moving speed of the sprayer, and the chemical spraying time of the sprayer for each section. And chemically spraying the substrate through the sprayer to variably change at least one to remove the impurities and the remaining cleaning liquid. The method of claim 1, wherein the removing of the impurities and the remaining cleaning liquid comprises: Spraying the chemical onto the substrate rotating at a first rotational speed while repeatedly moving the injection unit at a first moving speed between a predetermined point of the second section and a first position located inside the edge of the first section at a first moving speed; ; The chemical and the chemical on the substrate while moving the jetting portion at a second movement speed lower than the first movement speed in a second position direction located between the central portion of the substrate and the first position from a predetermined point of the second section. Injecting a dry gas to dry the water; Spraying the chemical and the dry gas onto the substrate while moving the spraying unit from the second position to the first position direction at a third movement speed lower than the second movement speed; And And spraying the chemicals and the dry gas onto the substrate rotating the spraying unit at a second rotational speed higher than the first rotational speed in the edge direction of the first section from the second position. The method of claim 2, wherein the spraying of the chemical while moving between the predetermined point of the second section and the first position comprises: And removing impurities remaining in the center portion of the substrate by spraying the chemical by stopping the spraying portion at a predetermined point of the second section for a predetermined time. The method of claim 3, wherein the predetermined time is 1/60 to 80/80 of the total time required for the step of injecting the chemical while the injection unit moves between the predetermined point of the second section and the first position. The substrate cleaning method characterized by the above-mentioned. 3. The method of claim 2, wherein the spraying of the chemical and the dry gas while moving from the second position toward the edge of the first section comprises: And removing the impurities remaining at the edge of the substrate by injecting the chemical and the dry gas by stopping the injection unit at the edge of the first section for a predetermined time. The method of claim 5, wherein the predetermined time is four to six times the total time required for the step of injecting the chemical and the dry gas while the injection unit moves from the second position to the edge of the first section. Substrate cleaning method, characterized in that. The substrate cleaning method of claim 2, wherein the jetting unit sprays the substrate using a material having a lower surface tension than the cleaning liquid as the chemical. The substrate cleaning method of claim 2, wherein the injection unit injects the chemical and the dry gas at different angles from each other. 3. The method of claim 2, wherein after spraying the chemical and the dry gas onto the substrate rotating at the second rotational speed, the drying gas is sprayed onto the substrate rotating at a third rotational speed higher than the second rotational speed. And drying the cleaning solution and the chemical.

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