Patent ID: 11862523
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 8:
9. An apparatus for detecting an endpoint of a grinding process, comprising:
a sensor, configured to periodically sense an interface of a reconstructed wafer formed by encapsulating a plurality of dies of at least two types placed on a carrier with an insulating layer to calculate a plurality of thicknesses from a surface of an insulating layer of the reconstructed wafer to the interface of the reconstructed wafer sensed by the sensor and generate a thickness signal comprising the thicknesses, wherein the thicknesses in the thickness signal comprise thicknesses from the surface of the insulating layer to interfaces of the dies of a first type and thicknesses from the surface of the insulating layer to interfaces of the dies of a second type different from the thicknesses from the surface of the insulating layer to the interfaces of the dies of the first type;
a timer, configured to generate a clock signal having a plurality of pulses with a time interval smaller than a time length of the thickness signal; and
a controller, coupled to the sensor and the timer, and configured to filter the thickness signal according to the clock signal to output a thickness maximum or a thickness minimum among the thicknesses in the thickness signal generated within each time interval according to an average thickness of a target die among the dies of the first type and the second type, wherein the thickness signal after the filtering is used to determine the endpoint of the grinding process being performed on the reconstructed wafer.