A method for processing semiconductor wafers, the method comprising: providing a first semiconductor wafer processed by a front-end process tool; obtaining measurement data from scan lines along a surface of the first semiconductor wafer, the measurement data of each scan line including a thickness profile and a surface profile, wherein the thickness profile includes thickness values of the first semiconductor wafer, and the surface profile includes surface heights of the first semiconductor wafer, the method characterized in that the method comprises: determining a center plane of the wafer based on the measurement data of the scan lines; generating, for each scan line, a raw shape profile based on the measurement data of the scan line and the center plane of the wafer; generating, for each scan line, an ideal shape profile based on polynomial regression of the raw shape profile; generating, for each scan line, a Gapi profile by: generating, for each scan line, a delta shape profile by comparing the raw shape profile and the ideal shape profile of the scan line; and generating, for each scan line, a weighting profile based on variations in the delta shape profile along a direction of the scan line; calculating a Gapi value of the first semiconductor wafer as a root-mean-square value of the Gapi profiles of the scan lines; comparing the Gapi value of the first semiconductor wafer to a predetermined threshold; if the Gapi value of the first semiconductor wafer is greater than the predetermined threshold: tuning the front-end process tool based on at least one of the Gapi profiles of the scan lines of the first semiconductor wafer; and processing a second semiconductor wafer with the tuned front-end process tool; and if the Gapi value of the first semiconductor wafer is less than or equal to the predetermined threshold, sorting the first semiconductor wafer for polishing. providing a first semiconductor wafer processed by a front-end process tool; obtaining measurement data from scan lines along a surface of the first semiconductor wafer, the measurement data of each scan line including a thickness profile and a surface profile, wherein the thickness profile includes thickness values of the first semiconductor wafer, and the surface profile includes surface heights of the first semiconductor wafer, the method characterized in that the method comprises: determining a center plane of the wafer based on the measurement data of the scan lines; generating, for each scan line, a raw shape profile based on the measurement data of the scan line and the center plane of the wafer; generating, for each scan line, an ideal shape profile based on polynomial regression of the raw shape profile; generating, for each scan line, a Gapi profile by: generating, for each scan line, a delta shape profile by comparing the raw shape profile and the ideal shape profile of the scan line; and generating, for each scan line, a weighting profile based on variations in the delta shape profile along a direction of the scan line; calculating a Gapi value of the first semiconductor wafer as a root-mean-square value of the Gapi profiles of the scan lines; comparing the Gapi value of the first semiconductor wafer to a predetermined threshold; if the Gapi value of the first semiconductor wafer is greater than the predetermined threshold: tuning the front-end process tool based on at least one of the Gapi profiles of the scan lines of the first semiconductor wafer; and processing a second semiconductor wafer with the tuned front-end process tool; and if the Gapi value of the first semiconductor wafer is less than or equal to the predetermined threshold, sorting the first semiconductor wafer for polishing. determining a center plane of the wafer based on the measurement data of the scan lines; generating, for each scan line, a raw shape profile based on the measurement data of the scan line and the center plane of the wafer; generating, for each scan line, an ideal shape profile based on polynomial regression of the raw shape profile; generating, for each scan line, a Gapi profile by: generating, for each scan line, a delta shape profile by comparing the raw shape profile and the ideal shape profile of the scan line; and generating, for each scan line, a weighting profile based on variations in the delta shape profile along a direction of the scan line; generating, for each scan line, a delta shape profile by comparing the raw shape profile and the ideal shape profile of the scan line; and generating, for each scan line, a weighting profile based on variations in the delta shape profile along a direction of the scan line; calculating a Gapi value of the first semiconductor wafer as a root-mean-square value of the Gapi profiles of the scan lines; comparing the Gapi value of the first semiconductor wafer to a predetermined threshold; if the Gapi value of the first semiconductor wafer is greater than the predetermined threshold: tuning the front-end process tool based on at least one of the Gapi profiles of the scan lines of the first semiconductor wafer; and processing a second semiconductor wafer with the tuned front-end process tool; and tuning the front-end process tool based on at least one of the Gapi profiles of the scan lines of the first semiconductor wafer; and processing a second semiconductor wafer with the tuned front-end process tool; and if the Gapi value of the first semiconductor wafer is less than or equal to the predetermined threshold, sorting the first semiconductor wafer for polishing.