Method for determining thickness of metal film of wafer, polishing device, and medium

A chemical mechanical polishing device, comprising:

• a polishing platen;
• a carrier head;
• a slurry supply apparatus;
• an eddy current sensor;
• and
• a controller, wherein:
• the carrier head is configured to load a to-be-polished wafer and press the wafer against a polishing pad arranged on the polishing platen;
• the slurry supply apparatus is configured to supply slurry between the polishing pad and the wafer;
• the eddy current sensor is configured to measure a reference thickness of a metal film on the wafer;
• and
• the controller is configured to execute a method for measuring a thickness of the metal film, the method comprising:
• determining the reference thickness of the metal film based on measurement signals collected by the eddy current sensor, wherein the measurement signals are indicative of measured thicknesses of different positions on the metal film;
• determining an adjustment parameter based on the reference thickness, wherein the adjustment parameter comprises sub-adjustment parameters respectively corresponding to a flat edge topography, a topography of an upwardly bending edge, and a topography of a downwardly bending edge;
• adjusting, based on the sub-adjustment parameters included in the adjustment parameter, a coordinate value of a sampling point in a to-be-processed area of the metal film;
• processing, based on an intermediate coordinate value obtained after adjustment of the coordinate value of the sampling point, an amplitude of the signal corresponding to the sampling point in the measurement signals;
• and
• determining the thickness of the metal film based on the processed signal amplitude,
• wherein the coordinate value of the sampling point is adjusted using the following formula:
• G(p)=k*(p+b)
• where, in the formula, p is the coordinate value of the sampling point in the to-be-processed area of the metal film, G(p) is the intermediate coordinate value corresponding to the sampling point, and k and b are two parameter values included in the sub-adjustment parameters;
• and
• wherein the processing, based on the intermediate coordinate value obtained after adjustment of the coordinate value of the sampling point, the amplitude of the signal corresponding to the sampling point in the measurement signals comprises:
• determining, based on the intermediate coordinate value corresponding to the sampling point in the to-be-processed area, an attenuation recovery coefficient corresponding to the sampling point;
• normalizing the attenuation recovery coefficient corresponding to the sampling point, to obtain an attenuation coefficient corresponding to the sampling point;
• and
• dividing the amplitude of the signal corresponding to the sampling point by the attenuation coefficient to obtain the processed signal amplitude.

A non-transitory computer storage medium storing instructions which, when executed by a processor, cause the processor to perform a method for measuring a thickness of a metal film of a wafer, the method comprises:

• determining a reference thickness of the metal film based on measurement signals collected by an eddy current sensor, the measurement signals being indicative of measured thicknesses of different positions on the metal film;
• determining an adjustment parameter based on the reference thickness, wherein the adjustment parameter comprises sub-adjustment parameters respectively corresponding to a flat edge topography, a topography of an upwardly bending edge, and a topography of a downwardly bending edge;
• adjusting, based on the sub-adjustment parameters included in the adjustment parameter, a coordinate value of a sampling point in a to-be-processed area of the metal film;
• processing, based on an intermediate coordinate value obtained after adjustment of the coordinate value of the sampling point, an amplitude of the signal corresponding to the sampling point in the measurement signals;
• and
• determining the thickness of the metal film based on the processed signal amplitude,
• wherein the coordinate value of the sampling point is adjusted using the following formula:
• G(p)=k*(p+b)
• where, in the formula, p is the coordinate value of the sampling point in the to-be-processed area of the metal film, G(p) is the intermediate coordinate value corresponding to the sampling point, and k and b are two parameter values included in the sub-adjustment parameters;
• and
• wherein the processing, based on the intermediate coordinate value obtained after adjustment of the coordinate value of the sampling point, the amplitude of the signal corresponding to the sampling point in the measurement signals, comprises:
• determining, based on the intermediate coordinate value corresponding to the sampling point in the to-be-processed area, an attenuation recovery coefficient corresponding to the sampling point;
• normalizing the attenuation recovery coefficient corresponding to the sampling point, to obtain an attenuation coefficient corresponding to the sampling point;
• and
• dividing the amplitude of the signal corresponding to the sampling point by the attenuation coefficient to obtain the processed signal amplitude.