Patent Publication Number: US-11648594-B2

Title: Wafer cleaning apparatus and wafer cleaning method using the same

Description:
This application claims priority to Korean Patent Application No. 10-2019-0108585, filed on Sep. 3, 2019, and all the benefits accruing therefrom under 35 U.S.C. § 119, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to wafer cleaning apparatuses and/or wafer cleaning methods using the same. 
     2. Description of the Related Art 
     A wet cleaning process in semiconductor fabrication etches a hard mask or the like on a wafer with liquid chemicals at high temperature. Wet cleaning processes have been conducted by a batch equipment in a related art. The batch equipment indicates a device which wet-cleans a set of wafers while precipitating a plurality of wafers, as one set, in liquid chemicals simultaneously, rather than one wafer. 
     With respect to the batch equipment, a problem may occur such as flow defect, dry fault, degradation in distribution uniformity or the like on the wafer. Accordingly, it is required for conversion into a single wafer equipment in order to solve the above-mentioned problem. A single wafer equipment indicates a device which applies each of wafers to the wet cleaning process one by one. 
     However, in the single wafer equipment, an etch rate (E/R) may become different according to position of a wafer. Accordingly, a method for tuning such an etch rate would be beneficial. 
     SUMMARY 
     At least one embodiment provides wafer cleaning apparatuses improved with etch efficiency by retaining temperature of a wafer within a previously established, or, alternatively, desired temperature range. 
     At least one embodiment provides wafer cleaning methods improved with etch efficiency by retaining temperature of a wafer within a previously established, or, alternatively, desired temperature range. 
     In one embodiment, a wafer cleaning apparatus may comprise a chamber configured to be loaded with a wafer, a nozzle on the wafer and configured to provide liquid chemicals on an upper surface of the wafer, a housing under the wafer, a laser module configured to irradiate laser on the wafer, a transparent window disposed between the wafer and the laser module, and a controller configured to control on/off of the laser module, wherein the controller is configured to control repetition of turning the laser module on and off, and retain a temperature of the wafer within a temperature range, and a ratio of time the laser module is on in one cycle of the on/off state of the laser module is 30% to 50%. 
     In one embodiment, a method for cleaning a wafer may include loading a wafer within a chamber, providing liquid chemicals on an upper surface of the wafer, irradiating laser to a lower surface of the wafer by turning on a laser module, retaining a temperature of the wafer within a temperature range by controlling an on/off state of the laser module, etching the wafer while the temperature of the wafer is retained within the temperature range, turning off the laser module after etching of the wafer completes, and unloading the wafer from the chamber. 
     In one embodiment, a method for cleaning a wafer may include loading a wafer including a first layer and a second layer within a chamber, providing liquid chemicals on an upper surface of the wafer, irradiating laser to a lower surface of the wafer by turning on a laser module, retaining a temperature of the wafer within a temperature range by controlling an on/off state of the laser module, a ratio of time the laser module is on is 30% to 50% in one cycle of the on/off state of the laser module, and etching the second layer of the wafer while the temperature of the wafer is retained within the temperature range. 
     The objectives that are intended to be addressed by the present disclosure are not limited to those mentioned above, and other objectives that are not mentioned above may be clearly understood to those skilled in the art based on the description provided below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of the present disclosure will become more apparent to those of ordinary skill in the art by describing in detail example embodiments thereof with reference to the accompanying drawings, in which: 
         FIG.  1    is a view provided to explain a wafer cleaning apparatus according to some example embodiments; 
         FIG.  2    is a top view provided to explain a wafer cleaning apparatus according to some example embodiments; 
         FIGS.  3  and  4    are graphical representation provided to explain temperature change of a wafer positioned on a wafer cleaning apparatus according to some example embodiments; 
         FIG.  5    is a view provided to explain a wafer cleaning apparatus according to some other example embodiments; 
         FIG.  6    is a view provided to explain a wafer cleaning apparatus according to some other example embodiments; 
         FIG.  7    is a view provided to explain a wafer cleaning apparatus according to some other example embodiments; 
         FIG.  8    is a top view provided to explain a wafer cleaning apparatus according to some other example embodiments; 
         FIG.  9    is a view provided to explain a wafer cleaning apparatus according to some other example embodiments; 
         FIG.  10    is a view provided to explain a wafer cleaning apparatus according to some other example embodiments; 
         FIGS.  11  and  12    are flowcharts provided to explain a method for cleaning a wafer according to some example embodiments; and 
         FIGS.  13  to  15    are views provided to explain a method for etching a wafer in a wafer cleaning method according to some example embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinbelow, a wafer cleaning apparatus according to some example embodiments will be described with reference to  FIGS.  1  to  4   . 
       FIG.  1    is a view provided to explain a wafer cleaning apparatus according to some example embodiments.  FIG.  2    is a top view provided to explain a wafer cleaning apparatus according to some example embodiments.  FIGS.  3  and  4    are graphical representation provided to explain temperature change of a wafer positioned on a wafer cleaning apparatus according to some example embodiments. 
     Referring to  FIGS.  1  to  4   , the wafer cleaning apparatus according to some example embodiments may include a chamber  10 , a bowl  20 , a housing  100 , a transparent window  105 , a laser module  110 , an aspherical lens  115 , a controller  120 , a laser supply unit  125 , an optical intensity detector  130 , a temperature sensor  140 , a spinner  150 , and/or a nozzle  160 . 
     A first direction X may be any one direction among horizontal directions. A second direction Y may be any one direction among horizontal directions different from the first direction X. The second direction Y may intersect the first direction X. For example, the second direction Y may be orthogonal to the first direction X. A third direction Z may intersect the first direction X and the second direction Y. The third direction Z may be orthogonal to both of the first direction X and the second direction Y, for example. The third direction Z may be, for example, an orthogonal direction. Accordingly, the first direction X, the second direction Y and the third direction Z may be orthogonal from one another. 
     A wet etching process and a cleaning process may be performed within the chamber  10 . The wafer W may be loaded within the chamber  10 . 
     The housing  100  may be positioned under the wafer W. That is, the housing  100  and the wafer W may be disposed sequentially in the third direction Z. The housing  100  may heat a lower surface of the wafer W. An upper surface of the housing  100  may be adjacent to a lower surface of the wafer W. However, the housing  100  and the wafer W may be spaced apart from each other. 
     The housing  100  may include the transparent window  105 , the laser module  110 , the aspherical lens  115 , the optical intensity detector  130 , and/or the temperature sensor  140  therewithin. The housing  100  may function to fix and support each position of the transparent window  105 , the laser module  110 , the aspherical lens  115 , the optical intensity detector  130 , and/or the temperature sensor  140 . 
     The housing  100  may be fixed under the wafer W. Accordingly, even though the wafer W rotates on a horizontal surface in parallel with an upper surface of the housing  100 , the housing  100  may not rotate. However, the present disclosure is not limited thereto. That is, according to some other example embodiments, the housing  100  may rotate with the wafer W or rotate separately from the wafer W. 
     The spinner  150  may be in contact with a side surface of the wafer W. The spinner  150  may rotate the wafer W by holding the wafer W on a side surface of the wafer W. As the spinner  150  rotates on a horizontal surface in parallel with an upper surface of the housing  100 , the wafer W may rotate in a same direction. However, the present disclosure is not limited thereto. 
     When the wafer W rotates with the spinner  150 , liquid chemicals  161  supplied to an upper surface of the wafer W may be uniformly distributed on an upper surface of the wafer W. Rotation of the wafer W with the spinner  150  may encourage an etch rate of an upper surface of the wafer W to be uniform. 
     The spinner  150  may include a grip portion  151  and a support portion  152 . The grip portion  151  may be a part which is in contact with a side surface of the wafer W. The grip portion  151  may be fixed to the wafer W by being in direct contact with a side surface of the wafer W. Accordingly, the grip portion  151  may rotate simultaneously with the wafer W on a horizontal surface in parallel with an upper surface of the housing  100 . 
     The grip portion  151  may include an insulating material. The wafer W is warmed to heated with several constituent elements within the housing  100 , e.g., the laser module  110 , and thus the grip portion  151  may block heat transfer so that another portion within the chamber  10  is prevented from being damaged. 
     The support portion  152  may be connected with the grip portion  151 . The support portion  152  may extend to a downside of the grip portion  151 . The support portion  152  may support the grip portion  151 . The support portion  152  may surround an outer side surface of the housing  100 . 
     The support portion  152  may rotate on a horizontal surface in parallel with an upper surface of the housing  100 , together with the grip portion  151 . For example, the entire support portion  152  may rotate, or only a portion of the support portion  152  may rotate. When only a portion of the support portion  152  rotates, a rotating portion among the support portion  152  may be connected with the grip portion  151 . Through the above, the wafer W may rotate on a horizontal surface in parallel with an upper surface of the housing  100 . 
     The spinner  150  may rotate the wafer W on a horizontal surface in parallel with an upper surface of the housing  100 , but at proper speed. When rotation speed of the spinner  150  is too fast, an edge portion of the wafer W may be cooled down differently from other portions of the wafer W, and temperature may not be distributed uniformly. For example, an etch rate may be different in a center portion and an edge portion of the wafer W. 
     Accordingly, rotation speed of the spinner  150  may be limited, for example, to 100-300 rpm. However, the present disclosure is not limited thereto. 
     The nozzle  160  may be positioned on the wafer W and the spinner  150 . The nozzle  160  may supply the liquid chemicals  161  to an upper surface of the wafer W. The nozzle  160  may drop the liquid chemicals  161  to a center portion of the wafer W. The wafer W may expand the dropping liquid chemicals  161  to an entire upper surface of the wafer W while rotating. Flow may be applied in a down direction for fixation of the wafer W and regular distribution of the liquid chemicals  161 . Through the above, the liquid chemicals  161  may be moved from a center of an upper surface of the wafer W to a surrounded region. 
     Although it is illustrated in  FIG.  1    that the nozzle  160  sprays the liquid chemicals  161  in a down direction from an upper surface of the wafer W, the present disclosure is not limited thereto. That is, according to some other example embodiments, the nozzle  160  may be disposed on a side surface of the wafer W at a point higher than an upper surface of the wafer W. Further, according to some other example embodiments, the nozzle  160  may discharge the liquid chemicals  161  in a side surface direction, and supply the liquid chemicals  161  to an upper surface of the wafer W. 
     The liquid chemicals  161  may be solution which etches an upper surface of the wafer W. For example, a silicon nitride layer (SiN) and/or polysilicon within the wafer W may become an etched object. However, the present disclosure is not limited thereto. 
     The liquid chemicals  161  may be different according to an etched object material. The liquid chemicals  161  may include, for example, at least one of phosphoric acid, ammonia solution, and tetramethylammonium hydroxide (TMAH). However, the present disclosure is not limited thereto. 
     The liquid chemicals  161  may be supplied by the nozzle  160 . The nozzle  160  may discharge the liquid chemicals  161  to an upper surface of the wafer W, and provide the liquid chemicals  161  at proper amount and speed. When the liquid chemicals  161  are supplied too much or too fast, elevation of temperature of the wafer W may become uneven. Accordingly, for example, the nozzle  160  may provide the liquid chemicals  161  on the wafer W at 0.1 L/min˜1 L/min of speed. However, the present disclosure is not limited thereto. 
     When the terms “about” or “substantially” are used in this specification in connection with a numerical value, it is intended that the associated numerical value includes a manufacturing or operational tolerance (e.g., ±10%) around the stated numerical value. Moreover, when the words “generally” and “substantially” are used in connection with geometric shapes, it is intended that precision of the geometric shape is not required but that latitude for the shape is within the scope of the disclosure. Further, regardless of whether numerical values or shapes are modified as “about” or “substantially,” it will be understood that these values and shapes should be construed as including a manufacturing or operational tolerance (e.g., ±10%) around the stated numerical values or shapes. 
     The bowl  20  may be disposed on an outer portion of the wafer W, the spinner  150  and the housing  100 . The bowl  20  may extend in the third direction Z to be higher than an upper surface of the wafer W. The bowl  20  may block outer discharge of the liquid chemicals  161  and fume in which the liquid chemicals  161  are evaporated. The bowl  20  may block another portion within the chamber  10  from being damaged. 
     The laser module  110  may be positioned within the housing  100 . The laser module  110  may irradiate the laser entirely on a lower surface of the wafer W. The laser module  110  may be disposed under the transparent window  105 . The laser L 1  irradiated by the laser module  110  may reach to a lower surface of the wafer W as passing through the transparent window  105 . 
     The wavelength of the laser provided from the laser module  110  may be, for example, 300 nm to 1,100 nm. However, the present disclosure is not limited thereto. 
     The transparent window  105  may be positioned on an upper surface of the housing  100 . The transparent window  105  may be a transparent material in which the laser L may penetrate through. For example, the transparent window  105  may include Quartz. However, the present disclosure is not limited thereto. 
     The transparent window  105  and the wafer W may be disposed to be closely adjacent to each other. Accordingly, the laser L penetrating through the transparent window  105  may not be discharged to another place than a lower surface of the wafer W. However, the present disclosure is not limited thereto. 
     The transparent window  105  and the wafer W may be spaced apart from each other. The above may be exemplified because the wafer W should rotate by the spinner  150  but the housing  100  installed with the transparent window  105  may not necessarily rotate. 
     As a lower surface of the wafer W may be heated entirely, a lower surface of the wafer W and an interfacial surface of the transparent window  105  may correspond to each other. That is, an edge portion of the wafer W may be exposed to the laser L by the transparent window  105 . 
     The aspherical lens  115  may be disposed within the housing  100 . The aspherical lens  115  may be connected with the laser module  110 . 
     The aspherical lens  115  may process the laser. Specifically, the laser L supplied with the laser module  110  may have Gaussian profile. The aspherical lens  115  may process the profile of the laser into a necessary, or, alternatively, desired shape. 
     Although it is illustrated in  FIG.  1    that the aspherical lens  115  is formed as one lens, this is only for convenience of explanation, and thus, the present disclosure is not limited thereto. That is, according to some other example embodiments, the aspherical lens  115  may include a plurality of lenses. 
     The laser supply unit  125  may supply the laser L to the laser module  110 . Although it is illustrated in  FIG.  1    that the laser supply unit  125  is connected with the controller  120 , this is only for convenience of explanation, and the present disclosure is not limited thereto. That is, according to some other example embodiments, the laser supply unit  125  may be directly connected with the laser module  110 . 
     The laser supply unit  125  may form a path where the laser L is supplied, as being connected externally. The laser supply unit  125  may include, for example, an optical fiber. However, the present disclosure is not limited thereto. 
     The controller  120  may control on/off of the laser module  110 . In other words, the control  120  may control turning the laser module  110  on and off, or, alternatively, the on/off state of the laser module  110 . Although it is illustrated in  FIG.  1    that the controller  120  is disposed between the housing  100  and the spinner  150 , the present disclosure is not limited thereto. 
     The controller  120  (and other circuitry) may include processing circuitry such as hardware including logic circuits; a hardware/software combination such as a processor executing software; or a combination thereof. For example, the processing circuitry more specifically may include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, application-specific integrated circuit (ASIC), etc. 
     Further, although it is illustrated in  FIG.  1    that the controller  120  is in contact with the laser module  110 , the present disclosure is not limited thereto. That is, in some other example embodiments, the controller  120  may be spaced apart from the laser module  110 . 
     Referring to  FIGS.  3  and  4   , as the controller  120  may control the laser module  110  repeatedly being on/off, the temperature Tp of the wafer W may be retained within a previously established, or, alternatively desired, temperature range. That is, the controller  120  may control the laser module  110  to turn on and off repeatedly, and thus control the temperature Tp of the wafer W to be within a temperature range. 
     Referring to  FIG.  3   , the controller  120  may control on/off of the laser module  110  to be performed repeatedly. Respective one on and one off of the laser module  110  may be defined as one cycle. The laser module  110  may repeat a cycle of off and on after being initially turned on. 
     For example, within one cycle of the laser module  110 , a ratio of time when the laser module  110  is on may be 30% to 50%. According to some example embodiments, within one cycle of the laser module  110 , a ratio of time when the laser module  110  is on may be 30%, and a ratio of time when the laser module  110  is off may be 70%. That is, t 2  (time when the laser module  110  is on):t 1  (time when the laser module  110  is off) may be 3:7. 
     Referring to  FIG.  4   , according to some other example embodiments, within one cycle of the laser module  110 , a ratio of time when the laser module  110  is on may be 50%, and a ratio of time when the laser module  110  is off may be 50%. That is, t 4  (time when the laser module  110  is on):t 3  (time when the laser module  110  is off) may be 5:5. 
     Time t 1  when the laser module  110  is on may be, for example, 0.5 to 3 seconds. However, the present disclosure is not limited thereto. 
     Power P of the laser L 2  irradiated from the laser module  110  may be uniformly retained in respective cases in which the laser module  110  is on/off. 
     For example, when the laser module  110  is on, second power P 2  of the laser L irradiated from the laser module  110  may be 0.1 kW to 100 kW. For example, when the laser module  110  is off, first power P 1  of the laser L irradiated from the laser module  110  may be 0 kW. However, the present disclosure is not limited thereto. That is, according to some other example embodiments, the first power P 1  of the laser L may be more than 0 kW. 
     Referring to  FIG.  3   , the controller  120  may retain the temperature Tp of the wafer W between the first temperature Tp 1  and the second temperature Tp 2  which is more than the first temperature Tp 1 . For example, each of the first temperature Tp 1  and the second temperature Tp 2  may be 170° C. to 250° C. For example, the first temperature Tp 1  may be 170° C., and the second temperature Tp 2  may be 250° C. However, the present disclosure is not limited thereto. 
     Temperature Tp of the wafer W may be elevated after the laser module  110  is initially on. Next, while on/off of the laser module  110  is performed repeatedly, temperature Tp of the wafer W may be retained between the first temperature Tp 1  and the second temperature Tp 2 . 
     While the temperature Tp of the wafer W is retained between the first temperature Tp 1  and the second temperature Tp 2 , which ranges within a previously established, or, alternatively, desired temperature range, an etch process of the wafer W (e.g., wet etching) may be performed. After an etching process of the wafer W completes, the laser module  110  may be off, and temperature of the wafer W may be lower than the first temperature Tp 1 . 
     Referring to  FIG.  4   , the controller  120  may retain the temperature Tp of the wafer W between third temperature Tp 3  and fourth temperature Tp 4  which is higher than the third temperature Tp 3 . For example, each of the third temperature Tp 3  and the fourth temperature Tp 4  may be 170° C. to 250° C. For example, the third temperature Tp 3  may be 170° C., and the fourth temperature Tp 4  may be 250° C. However, the present disclosure is not limited thereto. 
     Temperature Tp of the wafer W may be elevated after the laser module  110  is initially on. Subsequently, while on/off of the laser module  110  is performed repeatedly, the temperature Tp of the wafer W may be retained between the third temperature Tp 3  and the fourth temperature Tp 4 . 
     While an etching process with respect to the wafer W (e.g., wet etching) is performed, the temperature Tp of the wafer W may be retained between the third temperature Tp 3  and the fourth temperature Tp 4 , which ranges within a previously established, or, alternatively, desired temperature range. After an etching process with respect to the wafer W completes, the laser module  110  may be off, and the temperature of the wafer W may be lowered compared to the third temperature Tp 3 . 
     An etch rate of a layer formed in the wafer W may be mainly influenced by the temperature and concentration of an etchant. In the wafer cleaning apparatus according to some example embodiments, for example, the wafer W may include a silicon nitride layer (SiN) and a silicon oxide layer (SiO2), and a silicon nitride layer (SiN) may be selectively wet-etched. 
     When the etch temperature increases in order to increase an etch rate, a problem may occur such that a silicon oxide layer (SiO2) may be etched in addition to a silicon nitride layer (SiN). In the wafer cleaning apparatus according to some example embodiments, etch efficiency of a silicon nitride layer (SiN) may be enhanced by retaining the temperature Tp of the wafer W within a previously established, or, alternatively, desired temperature range while a silicon nitride layer (SiN) is selectively wet-etched. 
     The optical intensity detector  130  may be disposed inside the housing  100 . However, the present disclosure is not limited thereto. 
     The optical intensity detector  130  may detect the laser L reflecting from a lower surface of the wafer W and sense on/off of the laser module  110 . The controller  120  may control the laser module  110  by using on/off information of the laser module  110  detected by the optical intensity detector  130 . 
     The temperature sensor  140  may be disposed inside the housing  100 . However, the present disclosure is not limited thereto. 
     The temperature sensor  140  may sense the temperature of the wafer W. The controller  120  may control the laser module  110  by using the temperature information of the wafer W sensed by the temperature sensor  140 . 
     Hereinbelow, a wafer cleaning apparatus according to some other example embodiments will be described with reference to  FIG.  5   . The difference from the wafer cleaning apparatus illustrated in  FIG.  1    will be highlighted. 
       FIG.  5    is a view provided to explain a wafer cleaning apparatus according to some other example embodiments. 
     Referring to  FIG.  5   , the wafer cleaning apparatus according to some other example embodiments may include a reflecting plate  270  and a hollow region  280 . 
     The hollow region  280  may be disposed between the transparent window  205  and the laser module  110  within the housing  100 . The hollow region  280  may be empty space on an inner portion of the housing  100 . The hollow region  280  may be defined by the transparent window  205 , the reflecting plate  270  and/or a portion of the aspherical lens  115 . The hollow region  280  may be a region where the first laser L 1  irradiated from the laser module  110  goes toward a lower surface of the wafer W. 
     An upper surface of the hollow region  280  may be covered by the transparent window  205 . Accordingly, the hollow region  280  may be completely isolated from an external portion by the housing  100  and the transparent window  205 . The above may be performed for blocking pollution due to the liquid chemicals  161  of the laser module  110  and the hollow region  280  and fume which is generated by the liquid chemicals  161 . 
     The hollow region  280  may be vacuum in an inner portion. As a result, the first laser L 1  may go through easily. However, the present disclosure is not limited thereto. An inner portion of the hollow region  280  may be filled with gas medium, for example, which is not an obstacle for the first laser L 1  to go through. 
     The hollow region  280  may be a hemispheric shape. The hollow region  280  may be formed in a hemispheric shape because it should reflect the laser, which reflects with a lower surface of the wafer W, with the reflecting plate  270  again. However, the present disclosure is not limited thereto, for example, the hollow region  280  may be a polygonal shape which reflects the laser as above. Accordingly, the first laser L 1  may sequentially reflect with the wafer W and the reflecting plate  270 , and again, reach to a lower surface of the wafer W efficiently. 
     The reflecting plate  270  may be disposed along a lower surface of the hollow region  280 . The first laser L 1  irradiated from the laser module  110  may sequentially reflect with a lower surface of the wafer W and the reflecting plate  270  and may generate second laser L 2 . The second laser L 2  reflecting with the reflecting plate  270  may be provided to a lower surface of the wafer W again. 
     The laser generated as the first laser L 1  reflects with a lower surface of the wafer W may cause generation of damage in a device when reaching to another portion within the chamber  10 . Accordingly, the reflecting plate  270  may play a role of blocking the reflecting laser so as not to be in contact with another portion of the chamber  10 . Simultaneously, the second laser L 2  generated as the reflecting laser reflects again may reach to a lower surface of the wafer W and enhance efficiency of wafer W heating. 
     Hereinbelow, a wafer cleaning apparatus according to some other example embodiments will be described with reference to  FIG.  6   . The difference from the wafer cleaning apparatuses illustrated in  FIGS.  1  and  5    will be highlighted. 
       FIG.  6    is a view provided to explain a wafer cleaning apparatus according to some other example embodiments. 
     Referring to  FIG.  6   , in the wafer cleaning apparatus according to some other example embodiments, a reflecting plate  370  may be disposed along a sidewall and a bottom surface of a housing  100 . A hollow region  380  may be disposed between a transparent window  105  and the reflecting plate  370  within the housing  100 . 
     Hereinbelow, a wafer cleaning apparatus according to some other example embodiments will be described with reference to  FIGS.  7  and  8   . The difference from the wafer cleaning apparatus illustrated in  FIGS.  1  and  2    will be highlighted. 
       FIG.  7    is a view provided to explain a wafer cleaning apparatus according to some other example embodiments.  FIG.  8    is a top view provided to explain a wafer cleaning apparatus according to some other example embodiments. 
     Referring to  FIGS.  7  and  8   , the wafer cleaning apparatus according to some other example embodiments may include a spinner  450  and a fixation rotor module  490 . 
     The spinner  450  may include a grip portion  451 , a chemical drain guide  453 , an insulation block  454 , a first rotor  455 , a sidewall  458 , a bearing  456 , and a fixation portion  457 . 
     The spinner  450  may rotate the wafer W on a horizontal surface in parallel with an upper surface of the housing  100 . 
     The grip portion  451  may be a part which is in contact with a side surface of the wafer W. The grip portion  451  may be fixed to the wafer W as being in direct contact with a side surface of the wafer W. Accordingly, the grip portion  451  may rotate on a horizontal surface in parallel with an upper surface of the housing  100 . 
     The chemical drain guide  453  may guide a drain path of the liquid chemicals  161 . The chemical drain guide  453  may be connected with the grip portion  451 . The liquid chemicals  161  may be used in an etching process on an upper surface of the wafer W, and then, may be pushed away in a side surface of the wafer W with the flow. 
     Subsequently, the liquid chemicals  161  may reach to the chemical drain guide  453  after passing through the grip portion  451  of a side surface of the wafer W, and may be discharged. The liquid chemicals  161  may be discharged externally along the chemical drain guide  453 . 
     Because the chemical drain guide  453  is present on a lower position compared to the bowl  20 , it may prevent the liquid chemicals  161  from being discharged externally from the bowl  20 . Further, the chemical drain guide  453  may be disposed farther from the other constituent elements of the spinner  450 , e.g., the insulation block  454 , the first rotor  455 , the sidewall  458 , the bearing  456 , and the fixation portion  457  based on the wafer W. Accordingly, it may prevent the liquid chemicals  161  from damaging the insulation block  454 , the first rotor  455 , the sidewall  458 , the bearing  456 , and the fixation portion  457 . 
     The insulation block  454  may be disposed to constitute a sidewall of the spinner  450  between the grip portion  451  and the chemical drain guide  453 . The insulation block  454  may include an insulation material. The insulation block  454  may play a role of blocking without delivering the heat received by the grip portion  451  and the chemical drain guide  453  to the other constituent elements of the spinner  450 . 
     Although it is illustrated in  FIG.  1    that the insulation block  454  is in contact with the grip portion  451  and the chemical drain guide  453 , the present disclosure is not limited thereto. That is, according to some other example embodiments, position of the insulation block  454  may be modified. 
     Although it is illustrated in  FIG.  1    that the insulation block  454  is a single constituent element, the present disclosure is not limited thereto. That is, in some other example embodiments, the insulation block  454  may include a plurality of constituent elements. 
     The first rotor  455  may rotate the spinner  450  with a magnetic levitation method. The first rotor  455  may include a magnetic body. 
     Because the first rotor  455  may be fixed to the insulation block  454 , the sidewall  458  and the grip portion  451  of the spinner  450 , the spinner  450  may entirely rotate with rotation of the first rotor  455 . As a result, the wafer W may rotate together with the spinner  450 . 
     The sidewall  458  may be in contact with the first rotor  455  and may constitute a sidewall of the spinner  450 . Although it is illustrated in  FIG.  1    that the sidewall  458  is disposed between the first rotor  455  and the bearing  456 , the present disclosure is not limited thereto. The sidewall  458  may include every portion constituting a sidewall of the spinner  450 . Accordingly, the sidewall  458  may include a single constituent element as illustrated in  FIG.  1   , but may also include a plurality of constituent elements. 
     The bearing  456  may be disposed between the sidewall  458  and the fixation portion  457 . However, position of the bearing  456  may not be limited thereto. The bearing  456  may be disposed anywhere when being positioned between the fixed fixation portion  457  and the rotating first rotor  455 . 
     The bearing  456  may allow rotation of the spinner  450 . That is, the bearing  456  may be minimum constituent element for feasible rotation when the spinner  450  includes the fixed fixation portion  457 . 
     The bearing  456  may rotate together as the first rotor  455  rotates. The bearing  456  may simultaneously connect the fixation portion  457  with the sidewall  458 , the first rotor  455 , the insulation block  454 , the grip portion  451 , and the chemical drain guide  453 . Accordingly, the spinner  450  may rotate simultaneously while being fixed. 
     The fixation portion  457  may fix the spinner  450  under of the spinner  450 , and support. The fixation portion  457  may not rotate. Instead, the fixation portion  457  may be connected with the bearing  456 , so that a portion of the spinner  450  rotates. As a result, the spinner  450  may rotate the wafer W as several constituent elements, except for the fixation portion  457 , rotate. 
     The fixation rotor module  490  may be spaced apart from the spinner  450 . The fixation rotor module  490  may surround the spinner  450 . Specifically, the fixation rotor module  490  may be disposed between the chemical drain guide  453  and the first rotor  455 . However, the present disclosure is not limited thereto. 
     The fixation rotor module  490  may include a second rotor  491  and a rotor supporter  492 . The second rotor  491  may rotate the spinner  450  with a magnetic levitation method likewise in the first rotor  455  described above. The second rotor  491  may be spaced apart from the insulation block  454 , the sidewall  458  and the grip portion  451  of the spinner  450 . Further, the second rotor  491  may be connected with the rotor supporter  492 . 
     The second rotor  491  may include a magnetic body. The second rotor  491  may generate the rotation force through the magnetic force with the first rotor  455 . 
     Hereinbelow, a wafer cleaning apparatus according to some other example embodiments will be described with reference to  FIG.  9   . The difference from the wafer cleaning apparatus illustrated in  FIG.  7    will be highlighted. 
       FIG.  9    is a view provided to explain a wafer cleaning apparatus according to some other example embodiments. 
     Referring to  FIG.  9   , the wafer cleaning apparatus according to some other example embodiments may include a reflecting plate  570  and a hollow region  580 . 
     The hollow region  580  may be disposed between a transparent window  505  and a laser module  110  within a housing  100 . An upper surface of the hollow region  580  may be covered by the transparent window  505 . As a result, the hollow region  580  may be completely isolated from an external portion with the housing  100  and the transparent window  505 . The hollow region  580  may be a hemispheric shape. 
     The reflecting plate  570  may be disposed along a lower surface of the hollow region  580 . The first laser L 1  of  FIG.  5    irradiated from the laser module  110  may generate the second laser L 2  of  FIG.  5    as sequentially reflecting with a lower surface of the wafer W and the reflecting plate  570 . The second laser L 2  of  FIG.  5    reflecting with the reflecting plate  570  may be provided to a lower surface of the wafer W again. 
     Hereinbelow, a wafer cleaning apparatus according to some other example embodiments will be described with reference to  FIG.  10   . The difference from the wafer cleaning apparatuses illustrated in  FIGS.  7  and  9    will be highlighted. 
       FIG.  10    is a view provided to explain a wafer cleaning apparatus according to some other example embodiments. 
     Referring to  FIG.  10   , in the wafer cleaning apparatus according to some other example embodiments, the reflecting plate  670  may be disposed along a sidewall and a bottom surface of the housing  100 . The hollow region  680  may be disposed between the transparent window  105  and the reflecting plate  670  within the housing  100 . 
     Hereinbelow, a method for cleaning a wafer according to some example embodiments will be described with reference to  FIGS.  1  to  4    and  FIGS.  11  to  15   . 
       FIGS.  11  and  12    are flowcharts provided to explain a method for cleaning a wafer according to some example embodiments.  FIGS.  13  to  15    are views provided to explain a method for etching a wafer in a wafer cleaning method according to some example embodiments. 
     Referring to  FIGS.  1  to  4  and  11   , the wafer W may be loaded within the chamber  10  at S 110 . The wafer W may be loaded on the transparent window  105 . The wafer W may be held by the grip portion  151  of the spinner  150 . 
     Subsequently, the liquid chemicals  161  may be provided on an upper surface of the wafer W at S 120 . The liquid chemicals  161  may be provided on an upper surface of the wafer W through the nozzle  160 . 
     Subsequently, the controller  120  may irradiate the laser L to a lower surface of the wafer W by turning on the laser module  110  at S 130 . 
     For example, for example, as illustrated in  FIG.  3   , the laser L may be irradiated at second power P 2 . While the laser L is irradiated at the second power P 2 , temperature Tp of the wafer W may be elevated at more than the second temperature Tp 2 . 
     The laser L irradiated from the laser module  110  may be irradiated entirely to a lower surface of the wafer W as penetrating through the transparent window  105 . 
     Subsequently, the controller  120  may control on/off of the laser module  110 , and retain the temperature Tp of the wafer W within a previously established, or, alternatively, desired temperature range at S 140 . That is, the controller  120  may control on/off of the laser module  110 , and retain the temperature Tp of the wafer W between the first temperature Tp 1  to the second temperature Tp 2 . 
     Each of the first temperature Tp 1  and the second temperature Tp 2  may be 170° C. to 250° C. For example, the first temperature Tp 1  may be 170° C., and the second temperature Tp 2  may be 250° C. 
     Respective one on and one off of the laser module  110  may be defined as one cycle. For example, within one cycle of the laser module  110 , a ratio of time when the laser module  110  is on may be 30% to 50%. Time t 1  when the laser module  110  is on may be, for example, 0.5 to 3 seconds. 
     While the temperature Tp of the wafer W is retained between the first temperature Tp 1  to the second temperature Tp 2 , an etch process (e.g., wet etching) of the wafer W may be performed. 
     Specifically, referring to  FIG.  13   , the wafer W may include a first layer  1  and a second layer  2 . For example, the wafer W may include a first layer  1  and a second layer  2  which are alternately stacked from each other. The first layer  1  may be, for example, a silicon oxide layer (SiO2), and the second layer  2  may be, for example, a silicon nitride layer (SiN). The wafer W may include a trench R which penetrates through the first layer  1  and the second layer  2  in the third direction Z, for example. 
     The controller  120  may turn off the laser module  110  after the temperature Tp of the wafer W is elevated at more than the second temperature Tp 2 . 
     Referring to  FIGS.  12  and  14   , when the temperature Tp of the wafer W is declined to be close to the first temperature Tp 1 , the controller  120  may turn on the laser module  110 . 
     While the laser module  110  is on, the first layer  1  and the second layer  2  of the wafer W may be etched as an etchant is injected through a trench R formed on the wafer W at S 141 . For example, the second layer  2  may be further etched compared to the first layer  1 . That is, with respect to the first layer  1 , a portion corresponding to a first etch region E 1  exposed to the trench R may be etched, and with respect to the second layer  2 , a portion corresponding to a second etch region E 2  exposed to the trench R may be etched. The second etch region E 2  may be formed to be indented between the first layer  1 . 
     A formula, in which the first layer  1  (e.g., silicon oxide layer (SiO2)) is etched, is as follows (1).
 
SiO2+2H2O→Si(OH)4  (1)
 
     A formula, in which the second layer  2  (e.g., silicon nitride layer (SiN)) is etched, is as follows (2).
 
3Si3N4+27H2O+4H3PO4→4(NH4)3PO4+9H2SiO3  (2)
 
     A difference in etching amount between the first layer  1  and the second layer  2  may be caused from etch selectivity of the first layer  1  and the second layer  2  with respect to an etchant. 
     Referring to  FIGS.  12  and  15   , when the temperature Tp of the wafer W is elevated at the second temperature Tp 2 , the controller  120  may turn off the laser module  110 . 
     While the laser module  110  is off, the first layer  1  of the etched wafer W may be regenerated at S 142 . The first layer  1  may be regenerated on a portion corresponding to the first etch region E 1  of  FIG.  14   . For example, the first layer  1  may be regenerated until the temperature Tp of the wafer W falls down to the first temperature Tp 1 . 
     A formula, in which the first layer  1  (e.g., silicon oxide layer (SiO2)) is regenerated, is as follows (3).
 
Si(OH)4→SiO2+2H2O  (3)
 
     Until etching of the second layer  2  completes, the etching of the first layer  1  and the second layer  2  and regenerating of the first layer  1  may repeat. 
     When etching of the second layer  2  is etched as many as a previously established, or, alternatively, desired etching amount, an etching process with respect to the wafer W may complete at S 143 . 
     Referring to  FIGS.  1  to  4  and  11    again, after an etching process with respect to the wafer W completes, the controller  120  may turn off the laser module  110  at S 150 . After the laser module  110  is off, the temperature Tp of the wafer W may fall down under the first temperature Tp 1 . 
     Subsequently, a cleaning process with respect to the wafer W may be performed at S 160 . After a cleaning process with respect to the wafer W completes, the wafer W may be unloaded from the chamber  10  at S 170 . 
     Example embodiments according to the present disclosure were explained hereinabove with reference to the drawings attached, but it should be understood that the present disclosure is not limited to the aforementioned example embodiments, but may be fabricated in various different forms, and may be implemented by a person skilled in the art in other specific forms without altering the technical concept or essential characteristics of the present disclosure. Accordingly, it will be understood that the example embodiments described above are only illustrative, and should not be construed as limiting.