Wafer flatness evaluation method, wafer flatness evaluation apparatus carrying out the evaluation method, wafer manufacturing method using the evaluation method, wafer quality assurance method using the evaluation method, semiconductor device manufacturing method using the evaluation method and semiconductor device manufacturing method using a wafer evaluated by the evaluation method
View Patent ↗There is disclosed a wafer flatness evaluation method includes measuring front and rear surface shapes of a wafer. The wafer front surface measured is divided into sites. Then, a flatness calculating method is selected according to a position of the site to be evaluated and flatness in the wafer surface is acquired.
1. A wafer flatness evaluation method comprising:
measuring a thickness variation of a wafer in a free standing state;
deriving local flatness on a reference of a wafer rear surface on the assumption that the wafer rear surface is corrected to a flat plane based on the result of the measurement;
deriving a flatness transfer constant corresponding to magnitude of the local flatness on the reference of the wafer rear surface; and
calculating local flatness of the wafer front surface at the wafer holder chucking time based on a value of the flatness transfer constant and the local flatness on the reference of the wafer rear surface.
2. A wafer flatness evaluation method comprising:
measuring a thickness variation of a wafer in a free standing state;
deriving local flatness on a reference of a wafer rear surface on the assumption that the wafer rear surface is corrected to a flat plane based on the result of the measurement;
dealing with the local flatness on the reference of the wafer rear surface as a final result when magnitude of the local flatness on the reference of the wafer rear surface does not exceed a preset value and doing a simulation for chucking the wafer on a wafer holder when the magnitude of the local flatness on the reference of the wafer rear surface exceeds the preset value; and
calculating local flatness of the wafer front surface when the wafer is chucked on the wafer holder based on the result of simulation.
3. A wafer flatness evaluation method comprising:
measuring a thickness variation of a wafer in a free standing state;
deriving local flatness on a reference of a wafer rear surface on the assumption that the wafer rear surface is corrected to a flat plane based on the result of the measurement;
dealing with the local flatness on the reference of the wafer rear surface as a final result when magnitude of the local flatness on the reference of the wafer rear surface does not exceed a preset value and chucking the wafer on a wafer holder when the magnitude of the local flatness on the reference of the wafer rear surface exceeds the preset value; and
calculating local flatness based on the wafer front surface shape in the chucking state.
4. A wafer flatness evaluation apparatus comprising:
a measuring section which measures a thickness variation of a wafer in a free standing state;
a local flatness acquiring section which acquires local flatness on a reference of a wafer rear surface on the assumption that the rear surface of the wafer is corrected to a flat plane based on the result of the measurement;
a flatness transfer constant acquiring section which acquires a flatness transfer constant corresponding to magnitude of the local flatness on the reference of the wafer rear surface; and
a calculating section which calculates local flatness of the wafer front surface at the time of chucking on the wafer holder based on a value of the flatness transfer constant and the local flatness on the reference of the wafer rear surface.
5. A wafer flatness evaluation apparatus comprising:
a measuring section which measures a thickness variation of a wafer in a free standing state;
a local flatness acquiring section which acquires local flatness on a reference of a wafer rear surface on the assumption that the rear surface of the wafer is corrected to a flat plane based on the result of the measurement;
a simulation performing section which deals with the local flatness on the reference of the wafer rear surface as a final result when magnitude of the local flatness on the reference of the wafer rear surface does not exceed a preset value and performs a simulation for chucking the wafer on a wafer holder when the magnitude of the local flatness on the reference of the wafer rear surface exceeds the preset value; and
a calculating section which calculates local flatness of the wafer front surface when the wafer is chucked on the wafer holder based on the result of simulation.
6. A wafer flatness evaluation apparatus comprising:
a measuring section which measures a thickness variation of a wafer in a free standing state;
a local flatness acquiring section which acquires local flatness on a reference of a wafer rear surface on the assumption that the rear surface of the wafer is corrected to a flat plane based on the result of the measurement;
a chucking section which deals with the local flatness on the reference of the wafer rear surface as a final result when magnitude of the local flatness on the reference of the wafer rear surface does not exceed a preset value and chucks the wafer on a wafer holder when the magnitude of the local flatness on the reference of the wafer rear surface exceeds the preset value; and
a calculating section which calculates local flatness based on the wafer front surface shape in the chucking state.