Apparatus and methods for end point determination in reactive ion etching
First Claim
1. A method, comprising:
- receiving a wafer into an etch tool chamber for performing an RIE etch;
beginning the RIE etch to form vias in the wafer;
receiving in-situ measurements of one or more physical parameters of the etch tool chamber that are correlated to the RIE etch process;
providing a virtual metrology model for the RIE etch in the chamber;
inputting the received in-situ measurements to the virtual metrology model for the RIE etch in the chamber;
executing the virtual metrology model to estimate the current via depth;
comparing the estimated current via depth to a target depth; and
when the comparing indicates the current via depth is within a predetermined threshold of the target depth;
outputting a stop signal.
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Abstract
Methods and apparatus for performing end point determination. A method includes receiving a wafer into an etch tool chamber for performing an RIE etch; beginning the RIE etch to form vias in the wafer; receiving in-situ measurements of one or more physical parameters of the etch tool chamber that are correlated to the RIE etch process; providing a virtual metrology model for the RIE etch in the chamber; inputting the received in-situ measurements to the virtual metrology model for the RIE etch in the chamber; executing the virtual metrology model to estimate the current via depth; comparing the estimated current via depth to a target depth; and when the comparing indicates the current via depth is within a predetermined threshold of the target depth; outputting a stop signal. An apparatus for use with the method embodiment is disclosed.
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Citations
15 Claims
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1. A method, comprising:
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receiving a wafer into an etch tool chamber for performing an RIE etch; beginning the RIE etch to form vias in the wafer; receiving in-situ measurements of one or more physical parameters of the etch tool chamber that are correlated to the RIE etch process; providing a virtual metrology model for the RIE etch in the chamber; inputting the received in-situ measurements to the virtual metrology model for the RIE etch in the chamber; executing the virtual metrology model to estimate the current via depth; comparing the estimated current via depth to a target depth; and when the comparing indicates the current via depth is within a predetermined threshold of the target depth;
outputting a stop signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method, comprising:
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performing a plurality of RIE etch operations in an RIE chamber tool on a plurality of silicon wafers to form vias; during the plurality of RIE etch operations, collecting in-situ measurements of one or more physical parameters of the RIE chamber tool correlated to the resulting via depths; following the plurality of RIE etch operations, measuring the via depths obtained in the plurality of silicon wafers; performing a statistical analysis on the collected in-situ measurements and the measured via depths obtained, forming a virtual metrology model for the RIE etch operation in the RIE chamber tool; receiving a silicon wafer into the RIE chamber tool; beginning the RIE etch to form vias in the wafer; receiving in-situ measurements of one or more physical parameters of the etch tool chamber that are correlated to the depth of the vias in the RIE etch process; inputting the received in-situ measurements to the virtual metrology model for the RIE etch in the chamber; executing the virtual metrology model to estimate the current via depth; comparing the estimated current via depth to a target depth; and when the comparing indicates the current via depth is within a predetermined threshold of the target depth;
outputting a stop signal. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification