Patent Publication Number: US-11389922-B2

Title: Polishing measurement device and abrasion time controlling method thereof, and polishing control system including same

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application is a U.S. National Stage Application under 35 U.S.C. § 371 of PCT Application No. PCT/KR2017/000357, filed Jan. 11, 2017, which claims priority to Korean Patent Application No. 10-2016-0097788, filed Aug. 1, 2016, whose entire disclosures are hereby incorporated by reference. 
     TECHNICAL FIELD 
     The present embodiments relate to a polishing measurement device and a abrasion time controlling method thereof, and a polishing control system including same, and more particularly to a polishing measurement device and a abrasion time controlling method thereof for enhancing the polishing precision (flatness) of a wafer surface, and a polishing control system including same. 
     BACKGROUND ART 
     A wafer, which becomes a substrate during fabricating a semiconductor is fabricated through an ingot growing process for growing an ingot used as a raw material, a slicing process for slicing an ingot into a wafer shape, a lapping process for uniformizing and planarizing a thickness of a wafer, an etching process for removing and mitigating an occurred damage, a polishing process for mirror-polishing a surface of a wafer, and a cleaning process for cleaning a wafer and removing foreign substances adhered to a surface. 
     During the above-described process, a defect may occur on a surface and subsurface of a wafer. Types of defects include particles, scratches, crystal defects, subsurface roughness, and the like. 
     Nowadays, restrictions on the above-described surface defects of a wafer are rapidly strengthened, and in particular, as the wafer has a large-scale diameter, it is required to implement a high-quality defect-free wafer due to a processing characteristic of the wafer of a large-scale diameter. 
     However, a conventional polishing apparatus cannot precisely apply a polishing time, and surface defects of the wafer still occurred. 
     For example, a thickness measuring apparatus of a wafer surface disclosed in Japanese Patent Application Laid-Open No. 2008-227393 is disposed in a support frame away from an upper surface plate of a polishing apparatus, measures a thickness of a wafer surface without being influenced by vibration of rotation of the upper surface plate, and applies a polishing time to the polishing apparatus according to the measured thickness of the wafer surface to polish the wafer surface. 
     However, in the related art, since one polishing apparatus is controlled by each controller for controlling the above-described thickness measuring apparatus, installation cost of the controller and the like is increased, and measurement accuracy of a thickness is lowered due to limitation of the number of measurements of the wafer and a processing environment of a slurry. 
     DISCLOSURE 
     Technical Problem 
     The present embodiments are directed to providing a polishing measurement device and a abrasion time controlling method thereof for computing a correction value according to a surface shape of a wafer and reflecting the correction value on a polishing end point time, and a polishing control system including same. 
     In addition, the present embodiments are directed to providing a polishing measurement device and a abrasion time controlling method thereof for applying a polishing end point time to a controller for each polishing apparatus, and a polishing control system including same. 
     Technical Solution 
     According to an embodiment, there is provided a polishing measurement device, including: a shape scan unit configured to scan a wafer shape provided from at least one controller controlling a polishing time of each wafer; a profile determination unit configured to compute a thickness of the scanned wafer shape to determine at least one profile for a wafer type; an end point time computation unit configured to compute a PV value by the determined profile and compute a delta correction value and a polishing end point time by using the computed PV value and a set predicted PV value; and a polishing time change unit configured to transmit the computed polishing end point time to the at least one controller to change a polishing time of each of the wafers which is under polishing. 
     The wafer shape may be a result generated according to the polishing time. 
     The profile determination unit may compute a thickness by location located on the same line of each of the wafers. 
     The thickness may include at least one of a maximum thickness, a minimum thickness, an average thickness, a ¼ thickness, a 2/4 thickness and a ¾ thickness of each of the wafers by location. 
     The at least one profile may include convex shape, W shape, M shape and concave shape distinguished on the basis of the computed thickness of the wafer shape. 
     The delta correction value may be the predicted PV value−the PV value, and the polishing end point time may be a control time according to the PV value+/−the delta correction value. 
     The predicted PV value may be a predicted value based on a predicted polishing time by the at least one profile or environmental factors affecting the polishing time. 
     According to an embodiment, there is provided a polishing control system, including: a polishing measurement device configured to compute a thickness of a scanned wafer shape to determine at least one profile for a wafer type, and compute a delta correction value and a polishing end point time by using a computed PV value by the determined profile and a set predicted PV value; at least one controller configured to apply a polishing time of each of the wafers to a following polishing apparatus to obtain a shape of the wafer which is under polishing, and change the polishing time to the computed polishing end point time; and the polishing apparatus configured to primarily polish a surface of each of the wafers according to the polishing time and secondarily polish the surface of each of the wafers according to the changed polishing end point time. 
     The polishing apparatus may compute a thickness by location of each of the wafers located on the same line. 
     The thickness may include at least one of a maximum thickness, a minimum thickness, an average thickness, a ¼ thickness, a 2/4 thickness and a ¾ thickness of each of the wafers by location. 
     The at least one profile may include convex shape, W shape, M shape and concave shape distinguished on the basis of the computed thickness of the wafer shape. 
     The delta correction value may be the predicted PV value−the PV value, and the polishing end point time may be a control time according to the PV value+/−the delta correction value. 
     The predicted PV value may be a predicted value based on a predicted polishing time by the at least one profile or environmental factors affecting the polishing time. 
     According to an embodiment, there is provided a abrasion time controlling method, as a method for controlling a polishing end point time for each wafer of a plurality of controllers by a polishing measurement device, including: scanning a wafer shape provided from at least one controller; computing a thickness by location located on the same line of each of the wafers based on the scanned wafer shape; determining at least one profile for a wafer type based on the computed thickness by location; computing a PV value by the determined profile, and computing a delta correction value and a polishing end point time by using the computed PV value and a set predicted PV value; and changing the polishing time of each of the wafers which is under polishing by transmitting the computed polishing end point time to the at least one controller. 
     The thickness may include at least one of a maximum thickness, a minimum thickness, an average thickness, a ¼ thickness, a 2/4 thickness and a ¾ thickness of each of the wafers by location. 
     The at least one profile may include convex shape, W shape, M shape and concave shape distinguished on the basis of the computed thickness of the wafer shape. 
     The delta correction value may be the predicted PV value−the PV value, and the polishing end point time may be a control time according to the PV value+/−the delta correction value. 
     The predicted PV value may be a predicted value based on a predicted polishing time by the at least one profile or environmental factors affecting the polishing time. 
     Advantageous Effects 
     As described above, in the present embodiments, a correction value for each profile of a wafer type may be computed and a polishing time may be changed, and thus excellent flatness of a wafer surface without defects on the wafer surface can be achieved. 
     In addition, in the present embodiments, a plurality of controllers may be controlled by one polishing measurement device, and thus equipment cost can be significantly reduced. 
     The advantageous effects are not limited thereto, and other effects not described may be clearly understood by those skilled in the art from the description below. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block configuration diagram illustrating a connection relationship of a polishing measurement device according to an embodiment. 
         FIG. 2  is a block configuration diagram exemplarily illustrating an example of a polishing measurement device according to an embodiment. 
         FIG. 3  is a configuration diagram illustrating an example of an operation of a shape scan unit disclosed in the polishing measurement device of  FIG. 2 . 
         FIG. 4  is a configuration diagram illustrating an example of a profile obtained by a profile determination unit of the polishing measurement apparatus of FIG. 
         FIG. 5  is a block configuration diagram exemplarily illustrating an example of a polishing control system according to an embodiment. 
         FIG. 6  is a block configuration diagram exemplarily illustrating an example of a polishing measurement device according to an embodiment. 
         FIG. 7  is a flowchart exemplarily illustrating an example of a abrasion time controlling method according to an embodiment. 
         FIG. 8  is a diagram schematically illustrating a correlation between a wafer shape and a gap according to an embodiment. 
         FIG. 9  is a graph schematically illustrating a correlation between a wafer-like profile shape and a gap. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, a method and controllers disclosed in the following embodiments of the present invention will be described in detail with reference to the drawings. Terms used herein is for the purpose of describing a specific embodiment only and is not intended to limit embodiments of the invention. 
     Also, terms such as “including”, “having” or “configuring” described herein mean that components are present, unless specifically stated to the contrary, and thus should not be construed to exclude other components but to further include the other components. 
     Also, it is also to be understood that the singular form “the” used in the description of the embodiments disclosed in the following embodiments and claims are inclusive of plural expressions unless otherwise specified in the upper and lower contexts, and “and/or” should be understood to include any and all possible combinations of one or more of the related items listed. 
     In the following description of the embodiment, when it is described that each layer (film), region, pattern, or structure is formed “above/on” or “below/under” a substrate, each layer (film), region, pad or patterns, the description includes being formed both “directly” and “indirectly (by interposing another layer)” “above/on” or “below/under”. Also, a standard of above/on or below/under of each layer will be described based on the drawings. 
     Hereinafter, a polishing measurement device and a control method for a polishing time thereof, and a polishing control system including same will be described in detail based on the above-described viewpoints. 
     Embodiment of Connection of Polishing Measurement Device 
       FIG. 1  is a block configuration diagram illustrating a connection relationship of a polishing measurement device according to an embodiment. 
     Referring to  FIG. 1 , a polishing measurement device  100  according to an embodiment controls at least one controller  200  by internal communication or external communication. 
     For example, the polishing measurement device  100  may control each controller  200  simultaneously by transmitting control commands related to a computed computation algorithm to each controller  200 . 
     The above-described at least one controller  200  substantially applies the control commands related to the obtained computation algorithm to each of polishing apparatuses  300  connected by internal communication or external communication, and a wafer surface (a front surface and/or a rear surface) is polished in each polishing apparatus  300 . 
     Such at least one controller  200  may be separately connected to each polishing apparatus  300 , but may be disposed at inner portion of each polishing apparatus  300 . 
     Hereinafter, the polishing measurement device  100  for deriving the above-described computation algorithm will be described in more detail. 
     Embodiment of Polishing Measurement Device 
       FIG. 2  is a block configuration diagram exemplarily illustrating an example of a polishing measurement device according to an embodiment. 
     In addition,  FIG. 3  is a configuration diagram illustrating an example of an operation of a shape scan unit disclosed in the polishing measurement device of  FIG. 2 ,  FIG. 4  is a configuration diagram illustrating an example of a profile obtained by a profile determination unit of the polishing measurement apparatus of  FIG. 2 , and  FIGS. 3 and 4  will be supplementarily referred to in describing  FIG. 2 . 
     Referring to  FIG. 2 , the polishing measurement device  100  according to an embodiment includes a shape scan unit  110 , a profile determination unit  120 , an end point time computation unit  130 , and a polishing time change unit  140 . 
     In an embodiment, the shape scan unit  110  may receive a wafer shape (wafer shape information) from at least one controller controlling a polishing time of each wafer, and may scan the received wafer shape. 
     Preferably, the shape scan unit  110  may perform a scan on a front surface and/or a rear surface of a wafer. For example, as shown in  FIG. 3 , the shape scan unit  110  may scan an entire front surface of the wafer when the shape scan unit  110  passes from a location corresponding to a center of the front surface of the wafer through the center of the front surface of the wafer toward an end. The above-described shape scan unit  110  may be provided in a polishing apparatus  300 . 
     In an embodiment, the profile determination unit  120  may compute a thickness by each location for the wafer shape scanned by the shape scan unit  110 . For example, the shape scan unit  110  may compute a thickness by each location point located on the same line of the wafer. 
     Since a wafer surface by location located on the same line has an arbitrary shape like a bumpy shape, it is possible to compute the thickness. 
     Here, the above-described thickness may include at least one of a maximum thickness, a minimum thickness, an average thickness, a ¼ thickness, a 2/4 thickness and a ¾ thickness of a wafer surface of the wafer by location. 
     For example, when the arbitrary shape is bumpy, a highest height may be recognized and computed by the profile determination unit  120  as a maximum thickness, and a lowest height may be recognized by the profile determination unit  120  as a minimum thickness, and an average height therebetween may be recognized and computed by the profile determination unit  120  as an average thickness. 
     Likewise, when a ¼ thickness, a 2/4 thickness and a ¾ thickness, which are the remaining thickness elements, are also divided into ¼, 2/4 and ¾ from the center of the wafer surface, the thickness for each height may be computed by the profile determination unit  120 . 
     Furthermore, the profile determination unit  120  according to an embodiment may determine at least one profile, which is profile information, related to a wafer type based on at least one computed thickness, which is thickness information. 
     In other words, when the profile determination unit  120  recognizes at least one thickness element by location of the wafer surface on the same line, the shape may be easily predicted, and based on this, it is possible to sufficiently recognize at least one profile shape for the wafer type by location of the wafer surface. 
     The above-described at least one profile may include convex shape, W shape, M shape and concave shape distinguished on the basis of at least one computed thickness of the wafer shape. 
     Such at least one profile shape may be illustrated as in  FIG. 4 . The convex shape shown in  FIG. 4  requires a longer polishing time than the other types for planarization of the wafer surface, and then the polishing time may be shortened in the order of W shape, M shape and concave shape. However, the present invention is not limited to the above-described four types of the profile shape. 
     In an embodiment, the end point time computation unit  130  may compute a peak-to-valley value (PV value) by profile related to the four wafer shapes determined by the profile determination unit  120 . 
     When the PV value is computed, it is possible to recognize an actual polishable time by each profile as shown in  FIG. 4 . However, even though a primary polishing time is computed and applied to the polishing of the actual wafer surface, the flatness of the wafer surface may not be easily implemented due to occurring errors. 
     In order to prevent this, the end point time computation unit  130  may set a predicted PV value in advance and utilize the PV value for planarization of the wafer surface. The above-described predicted PV value may be a predicted value based on a predicted polishing time by each of at least one profile and/or environmental factors affecting the polishing time. 
     Accordingly, the end point time computation unit  130  according to an embodiment may compute a delta correction value capable of reducing an error by using the computed PV value and the set predictive PV value, and may compute the polishing end point time to be applied to the polishing of the wafer surface by each profile by using the computed delta correction value. 
     For example, a delta correction value D may be obtained by an operation of the following Equation 1, and a polishing end point time T may be computed by using the delta correction value D that has already been obtained and a control time t computed according to each PV value. 
     That is, the end point time computation unit  130  may compute the polishing end point time T by the following Equation 2. As the above-described PV value is lower, the flatness (global flatness values (GBIR)) of the wafer surface is better, so that the control time t may be determined according to the PV value.
 
Delta correction value  D =Predicted  PV  value− PV  value  [Equation 1]
 
The polishing end point time  T  is the control time  t  according to the  PV  value±the delta correction value  D   [Equation 2]
 
     Finally, in an embodiment, the polishing time change unit  140  may transmit the polishing end point time T computed by the end point time computation unit  130  to at least one controller  200  connected by internal communication or external communication. 
     As described above, since the computed polishing end point time T is transmitted to each controller  200 , the polishing end point time T obtained by each controller  200  may be different. Accordingly, the polishing measurement device  100  according to an embodiment may simultaneously control at least one controller  200  by transmitting an algorithm computed for each controller  200  to a corresponding controller  200 . 
     However, the conventional apparatus neither applies the above-described computation algorithm, nor provides a mechanism for controlling each controller  200  simultaneously. 
     The at least one controller  200  receiving the polishing end point time T may change the polishing time of each wafer which is under primary polishing according to the obtained polishing end point time. 
     That is, the at least one controller  200  may change the primary polishing time to the polishing end point time which is a secondary polishing time, and apply to each polishing apparatus  300 . Accordingly, each polishing apparatus  300  perform the polishing of the wafer surface according to the changed secondary polishing end point time. 
     As described above, in the present embodiment, the correction value by each profile of the wafer type is computed and the polishing time is changed and applied, so that excellent flatness may be implemented on the surface of the wafer without defects on the wafer surface and a plurality of controllers may be simultaneously controlled, and thus equipment cost can be significantly reduced. 
     Embodiment of Polishing Control System 
       FIG. 5  is a block configuration diagram exemplarily illustrating an example of a polishing control system according to an embodiment. 
     Referring to  FIG. 5 , a polishing control system  400  according to an embodiment includes a polishing measurement device  410 , a controller  420 , and a polishing apparatus  430 . 
     In an embodiment, the polishing measurement device  410  is connected to a plurality of controllers  420  by internal communication or external communication, respectively, and performs each algorithm for planarizing a surface of a wafer to apply to each controller  420 . 
     The internal communication or the external communication is a generally known connection, and thus a description thereof will be omitted. 
     In an embodiment, the controller  420  is disposed one by one for each polishing apparatus  430  and substantially controls the polishing apparatus  430 , and each polishing apparatus  430  may be controlled according to a control command (control command by the computation algorithm) of the polishing measurement device  410 . 
     Further, when the controller  420  applies a polishing time provided from the polishing measurement device  410  to each polishing apparatus  430 , each polishing apparatus  430  may primarily polish the surface of each wafer (including the front and rear surfaces of the wafer) according to the polishing time. 
     Furthermore, the controller  420  obtains the shape (shape information) of each polished wafer according to the primary polishing time from each polishing apparatus  430 , and may transmit to one polishing measurement device  410  by the internal communication or the external communication. 
     The internal communication or the external communication, which is a means of connection between each of the above-described components, is a generally known connection, and thus a description thereof will be omitted. 
     Accordingly, the polishing measurement device  410  according to an embodiment may generate the above-described computation algorithm based on the shape of each wafer received from the plurality of controllers  420 , and transmit the polishing end point time included in the generated computation algorithm to each controller  420 . 
     Each controller  420  may apply the obtained polishing end point time to each polishing apparatus  430  to change the polishing time which is under polishing, and each polishing apparatus  430  may perform secondary polishing for the wafer surface based on the changed polishing end point time. 
     Meanwhile, one controller  420  may be connected to each polishing apparatus  300  by the internal or the external communication, but may be disposed inside thereof as one component of each of the polishing apparatuses  300 . 
     Hereinafter, the polishing measurement device  410  for generating the above-described computation algorithm will be described in more detail. 
     Detailed Embodiment of Polishing Measurement Device 
       FIG. 6  is a block configuration diagram exemplarily illustrating an example of a polishing measurement device according to an embodiment. The above-described  FIGS. 3 and 4  will be supplementarily referred to in describing  FIG. 6 . 
     Referring to  FIG. 6 , the polishing measurement device  410  according to an embodiment may receive a wafer shape (wafer shape information) from at least one controller controlling a polishing time of each wafer, and may scan the received wafer shape. 
     Preferably, the polishing measurement device  410  may perform a scan on a front surface and/or a rear surface of the wafer. For example, as shown in  FIG. 3 , the polishing measurement device  410  may scan an entire front surface of the wafer when passing from a location corresponding to a center of the front surface of the wafer through the center of the front surface of the wafer toward an end. 
     Furthermore, the polishing measurement device  410  may compute a thickness by each location for the wafer shape that has already been scanned. The polishing measurement device  410  may compute a thickness by each location point located on the same line of the wafer. 
     Since the wafer surface by location located on the same line has an arbitrary shape like a bumpy shape, it is possible to compute the thickness. 
     Here, the above-described thickness may include at least one of a maximum thickness, a minimum thickness, an average thickness, a ¼ thickness, a 2/4 thickness and a ¾ thickness of a wafer surface of the wafer by location. 
     For example, when an arbitrary shape is bumpy, a highest height in the arbitrary shape may be used as a maximum thickness, and a lowest height may be used as a minimum thickness, and an average height therebetween may be used as an average thickness. 
     Likewise, when dividing into ¼, 2/4, and ¾ from the center of the arbitrary shape, each height may be used in ¼, 2/4, and ¾ thicknesses. 
     Furthermore, the polishing measurement device  410  may determine at least one profile (profile information) related to a wafer type based on at least one computed thickness (thickness information). 
     More specifically, when the polishing measurement device  410  recognizes at least one thickness element by location of the wafer surface on the same line, the shape may be easily predicted, and based on this, it is possible to sufficiently recognize at least one profile shape for the wafer type by location of the wafer surface. 
     The above-described at least one profile may include convex shape, W shape, M shape and concave shape distinguished on the basis of at least one computed thickness of the wafer shape as shown in  FIG. 3 . 
     Such at least one profile shape may be illustrated as in  FIG. 4 . The convex shape shown in  FIG. 4  requires a longer polishing time than the other types for planarization of the wafer surface, and then the polishing time may be shortened in the order of W shape, M shape and concave shape. However, the present invention is not limited to the above-described four types of the profile shape. 
     In an embodiment, the polishing measurement device  410  may compute a peak-to-valley value (PV value) by profile related to the four determined wafer shapes. 
     When the PV value is computed, it is possible to recognize an actual polishable time by each profile as shown in  FIG. 4 . However, even though a primary polishing time is computed and applied to the polishing of the actual wafer surface, the flatness of the wafer surface may not be easily implemented due to occurring errors. 
     In order to prevent this, the polishing measurement device  410  may set a predicted PV value in advance and utilize the PV value for planarization of the wafer surface. The above-described predicted PV value may be a predicted value based on a predicted polishing time by each of at least one profile and/or environmental factors affecting the polishing time. 
     Accordingly, the polishing measurement device  410  may compute a delta correction value capable of reducing an error by using the computed PV value and the set predictive PV value, and may compute the polishing end point time to be applied to the polishing of the wafer surface by each profile by using the computed delta correction value. 
     For example, a delta correction value D may be obtained by an operation of the following Equation 3, and a polishing end point time T may be computed by using the delta correction value D that has already been obtained and a control time t computed according to each PV value. 
     That is, the polishing measurement device  410  may compute the polishing end point time T by the following Equation 4. As the above-described PV value is lower, the flatness (global flatness values (GBIR)) of the wafer surface is better, so that the control time t may be determined according to the PV value.
 
Delta correction value  D =Predicted  PV  value− PV  value  [Equation 3]
 
The polishing end point time  T  is the control time  t  according to the  PV  value±the delta correction value  D   [Equation 4]
 
     In an embodiment, the polishing measurement device  410  may transmit the polishing end point time T that has been already computed to at least one controller  420  connected by the internal communication or the external communication. 
     As described above, since the computed polishing end point time T is transmitted to each controller  420 , the polishing end point time T obtained by each controller  420  may be different. Accordingly, the polishing measurement device  410  according to an embodiment may simultaneously control at least one controller  420  by transmitting the algorithm computed for each controller  420  to a corresponding controller  420 . 
     However, the conventional apparatus neither applies the above-described computation algorithm, nor provides a mechanism for controlling each controller  420  simultaneously. 
     The at least one controller  420  receiving the polishing end point time T may change the polishing time of each wafer which is under primary polishing according to the polishing end point time that has already been obtained. 
     That is, the at least one controller  420  may change the primary polishing time to the polishing end point time which is a secondary polishing time, and apply to each polishing apparatus  430 . Accordingly, each polishing apparatus  430  performs the polishing for the wafer surface according to the changed secondary polishing end point time. 
     As described above, in the present embodiment, the correction value by each profile of the wafer type is computed and the polishing time is changed and applied, so that excellent flatness may be implemented on the surface of the wafer without defects on the wafer surface and a plurality of controllers may be simultaneously controlled, and thus equipment cost can be significantly reduced. 
     Embodiment of Control Method for Polishing Time 
       FIG. 7  is a flowchart exemplarily illustrating an example of a abrasion time controlling method according to an embodiment. 
     The abrasion time controlling method  500  according to an embodiment controls a primary polishing time and a secondary polishing time for each wafer of a plurality of controllers by a polishing measurement device. 
     Here, the primary polishing time refers to a time for primary polishing of each wafer surface (for example, including the front and rear surfaces), and the above-described secondary polishing time is a time for which the primary polishing time is corrected, which may refer to a time for polishing again for each wafer surface polished once. 
     Since the above-described polishing measurement device has been described in  FIGS. 1 to 6 , a description thereof will be omitted, but is also applied in the present embodiment. However, in the present embodiment, only an entire configuration or a part of the configuration of the polishing measurement device of  FIGS. 1 to 6  may be implemented. 
     The method for controlling the polishing time  500  implemented by the above-described polishing measurement device is as follows. 
     Referring to  FIG. 7 , the method for controlling the polishing time  500  according to an embodiment includes steps  510  to  550  for performing planarization of a wafer surface by the polishing measurement device. 
     Firstly, in an exemplary step  510 , the polishing measurement device may scan a wafer shape (shape information of a wafer) provided from at least one controller. The wafer shape may be shape information of the primarily processed wafer. 
     In an exemplary step  520 , the polishing measurement device may compute a thickness by location located on the same line of each wafer based on the wafer shape that has already been scanned. 
     The thickness used in the computation may include at least one of a maximum thickness, a minimum thickness, an average thickness, a ¼ thickness, a 2/4 thickness and a ¾ thickness of each of the wafers by location located on the same line. Such an example has been fully discussed in  FIG. 3  and may also be applied to the present embodiment. 
     In an exemplary step  530 , the polishing measurement device may determine at least one profile related to a wafer type based on the thickness by location of the wafer surface that has been already computed. 
     For example, the above-described at least one profile may include convex shape, W shape, M shape and concave shape distinguished on the basis of the computed thickness of the wafer shape. Such an example has been fully discussed in  FIG. 4  and may also be applied to the present embodiment. 
     In an exemplary step  540 , the polishing measurement device may compute a PV value by each profile that has already been determined, and may compute a delta correction value and a polishing end point time by using the computed PV value and a set predicted PV value. 
     The above-described delta correction value may refer to the predicted PV value−the PV value, the polishing end point time may refer to a control time according to the PV value that has already been computed±the delta correction value, and the predicted PV value may be a predicted value based on a predicted polishing time by each of at least one profile or environmental factors affecting the polishing time. 
     Finally, in an exemplary step  550 , the polishing measurement device may transfer the polishing end point time that has already been computed to at least one controller to change the polishing time of each wafer which is under polishing. 
     For example, at least one controller may change the primary polishing time to the polishing end point time which is the secondary polishing time, and apply to each polishing apparatus. Accordingly, each polishing apparatus performs the polishing for the wafer surface according to the changed secondary polishing end point time. 
     As described above, in the present embodiment, the correction value by each profile of the wafer type is computed and the polishing time is changed and applied, so that excellent flatness may be implemented on the surface of the wafer without defects on the wafer surface and a plurality of controllers may be simultaneously controlled, and thus equipment cost can be significantly reduced. 
     Meanwhile, the above-described predicted PV value, the delta correction value, and/or the polishing end point time may be a value set according to, for example, the profile shape of four wafer types, but a computation result may vary. Hereinafter, it will be described in more detail. 
     Embodiment of Correlation Between Gap and Wafer Thickness/Profile 
       FIG. 8  is a diagram schematically illustrating a correlation between a wafer shape and a gap according to an embodiment, and  FIG. 9  is a graph schematically illustrating a correlation between a wafer-like profile shape and a gap. 
     The polishing measurement device described in  FIGS. 1 to 7  may set a predicted PV value so as to increase or decrease a polishing time according to a profile shape (shape of a wafer surface) of, for example, four types of wafers for planarization of the wafer surface, and may compute a polishing end point time. 
     For example, a wafer-like dotted line shown in  FIG. 8  is the wafer shape when the polishing time is short, and as a gap between the height of wafer shape of the dotted line and the carrier is large, the edge shape of the wafer is also highly roll-off, so that it may have a convex shape profile shape. 
     In the case of the convex shape profile shape, when the polishing time is increased, the convex shape profile shape becomes a wafer shape of a solid line, the gap between the height of the wafer shape of the solid line and the carrier is reduced correspondingly, and the roll-off of the edge shape of the wafer also decreases. When a correlation of such a gap is applied to a profile type, it can be expressed as shown in  FIG. 9 . 
     The convex shape profile type shown in  FIG. 9  has the largest difference in gap, and the difference in gap is smaller in the order of in the profile shapes of the W shape, M shape and concave shape. 
     Accordingly, in the polishing measurement device described in  FIGS. 1 to 7 , when the profile shape of the wafer is a convex shape, the polishing end point time is increased so as to be a concave shape, and as the center polishing amount of the wafer surface increases, a predicted PV value etc. may be set in a direction approaching to flatness, and the profile shape of the rest of W shape, M shape and concave shape may also set the predicted PV value etc. in the direction approaching to the flatness in consideration of the gap difference in  FIG. 8 . 
     Accordingly, in the embodiments of  FIGS. 1 to 7 , the delta correction value and the polishing end point time reflecting the predicted PV value etc. described above may contribute greatly to achieve the flatness of the wafer surface. 
     It will be obvious to those skilled in the art that the present embodiments disclosed above may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. 
     Accordingly, the above detailed description should not be construed restrictively in all aspects and should be regarded as illustrative. The scope of the present embodiment should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present embodiment are included in the scope of the present embodiment. 
     MODES OF THE INVENTION 
     The mode for carrying out the invention has been fully described in the foregoing “Best Mode for Carrying out the Invention”. 
     INDUSTRIAL APPLICABILITY 
     The above-described polishing measurement device and the method for controlling the polishing time thereof, and the polishing control system including same may compute a correction value according to a surface shape of a wafer and reflect the same on the polishing end point time, and apply the polishing end point time to a controller for each polishing apparatus. Therefore, it is possible to apply to a wafer fabricating apparatus capable of fabricating a wafer having excellent flatness without defects on a wafer surface.