US 12,435,964 B2
Contactless capacitive measurement tool with improved throughput and accuracy
Daniel Fulford, Albany, NY (US); Mark I. Gardner, Austin, TX (US); and Henry Jim Fulford, Albany, NY (US)
Assigned to Tokyo Electron Limited, Tokyo (JP)
Filed by Tokyo Electron Limited, Tokyo (JP)
Filed on Nov. 16, 2023, as Appl. No. 18/511,086.
Prior Publication US 2025/0164230 A1, May 22, 2025
Int. Cl. G01B 7/28 (2006.01); G01D 5/24 (2006.01); G01R 27/26 (2006.01); H01L 21/67 (2006.01)
CPC G01B 7/28 (2013.01) [G01D 5/24 (2013.01); G01R 27/2605 (2013.01); H01L 21/67288 (2013.01)] 23 Claims
OG exemplary drawing
 
13. A metrology tool for measuring wafer bow, the metrology tool comprising:
a wafer mount configured to support a semiconductor wafer;
a bar-shaped capacitive sensor unit including:
a sensor housing having a first surface, the first surface facing a surface of the semiconductor wafer when the bar-shaped capacitive sensor unit is in close proximity to the semiconductor wafer; and
a plurality of electrodes provided on the first surface of the sensor housing and arranged in a line along a length of the sensor housing, wherein each electrode works in conjunction with a corresponding opposing area on the surface of the semiconductor wafer to form a capacitor with: (a) the electrode forming a top plate of the capacitor, and (b) the corresponding opposing area on the surface of the semiconductor wafer forming a bottom plate of the capacitor;
a movement device configured to move at least one of the wafer mount and the bar-shaped capacitive sensor unit relative to each other; and
a controller configured to: (a) obtain a plurality of capacitance values from the plurality of electrodes by measuring a capacitance between each electrode and the corresponding opposing area on the surface of the semiconductor wafer, (b) calculate a distance between each electrode and the corresponding opposing area of the surface of the semiconductor wafer based on the capacitance value measured at the electrode, and (c) determine a bow of the semiconductor wafer based on the calculated distances.