Automated process control using optical metrology and photoresist parameters
First Claim
1. A method of controlling a photolithography cluster using optical metrology, the method comprising:
- a) fabricating a structure on a wafer using a photolithography cluster;
b) obtaining a measured diffraction signal off the structure;
c) comparing the measured diffraction signal to a simulated diffraction signal, wherein the simulated diffraction signal is associated with one or more values of one or more photoresist parameters, wherein the one or more photoresist parameters characterize behavior of photoresist when the photoresist undergoes processing steps in the photolithography cluster, wherein the simulated diffraction signal was generated using one or more values of one or more profile parameters, and wherein the one or more values of the one or more profile parameters used to generate the simulated diffraction signal were derived from the one or more values of the one or more photoresist parameters associated with the simulated diffraction signal;
d) if the measured diffraction signal and the simulated diffraction signal match, then determining one or more values of one or more photoresist parameters used in the photolithography cluster to be the one or more values of the one or more photoresist parameters associated with the matching simulated diffraction signal; and
e) adjusting one or more process parameters or equipment settings of the photolithography cluster based on the one or more values of the one or more photoresist parameters determined in d).
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Abstract
To control a photolithography cluster using optical metrology, a structure is fabricated on a wafer using the photolithography cluster. A measured diffraction signal off the structure is obtained. The measured diffraction signal is compared to a simulated diffraction signal. The simulated diffraction signal is associated with one or more values of one or more photoresist parameters. The one or more photoresist parameters characterize behavior of photoresist when the photoresist undergoes processing steps in the photolithography cluster. The simulated diffraction signal was generated using one or more values of one or more profile parameters. The one or more values of the one or more profile parameters used to generate the simulated diffraction signal were derived from the one or more values of the one or more photoresist parameters associated with the simulated diffraction signal. If the measured diffraction signal and the simulated diffraction signal match, then one or more values of one or more photoresist parameters used in the photolithography cluster are determined to be the one or more values of the one or more photoresist parameters associated with the matching simulated diffraction signal. One or more process parameters or equipment settings of the photolithography cluster are adjusted based on the one or more values of the one or more photoresist parameters.
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Citations
24 Claims
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1. A method of controlling a photolithography cluster using optical metrology, the method comprising:
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a) fabricating a structure on a wafer using a photolithography cluster; b) obtaining a measured diffraction signal off the structure; c) comparing the measured diffraction signal to a simulated diffraction signal, wherein the simulated diffraction signal is associated with one or more values of one or more photoresist parameters, wherein the one or more photoresist parameters characterize behavior of photoresist when the photoresist undergoes processing steps in the photolithography cluster, wherein the simulated diffraction signal was generated using one or more values of one or more profile parameters, and wherein the one or more values of the one or more profile parameters used to generate the simulated diffraction signal were derived from the one or more values of the one or more photoresist parameters associated with the simulated diffraction signal; d) if the measured diffraction signal and the simulated diffraction signal match, then determining one or more values of one or more photoresist parameters used in the photolithography cluster to be the one or more values of the one or more photoresist parameters associated with the matching simulated diffraction signal; and e) adjusting one or more process parameters or equipment settings of the photolithography cluster based on the one or more values of the one or more photoresist parameters determined in d). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A computer-readable storage medium containing computer-executable instructions to control a photolithography cluster using optical metrology, comprising instructions for:
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a) obtaining a measured diffraction signal off a structure fabricated on a wafer using a photolithography cluster; b) comparing the measured diffraction signal to a simulated diffraction signal, wherein the simulated diffraction signal is associated with one or more values of one or more photoresist parameters, wherein the one or more photoresist parameters characterize behavior of photoresist when the photoresist undergoes processing steps in the photolithography cluster, wherein the simulated diffraction signal was generated using one or more values of one or more profile parameters, and wherein the one or more values of the one or more profile parameters used to generate the simulated diffraction signal were derived from the one or more values of the one or more photoresist parameters associated with the simulated diffraction signal; c) if the measured diffraction signal and the simulated diffraction signal match, then determining one or more values of one or more photoresist parameters used in the photolithography cluster to be the one or more values of the one or more photoresist parameters associated with the matching simulated diffraction signal; and d) adjusting one or more process parameters or equipment settings of the photolithography cluster based on the one or more values of the one or more photoresist parameters determined c). - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A system to control a photolithography cluster using optical metrology, the system comprising:
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a photolithography cluster configured to perform a photolithographic process to fabricate a structure on a wafer; an optical metrology system comprising; a beam source and detector configured to measure a diffraction signal off the structure; a processor connected to the beam source and detector, wherein the processor is configured to compare the measured diffraction signal to a simulated diffraction signal, wherein the simulated diffraction signal is associated with one or more values of one or more photoresist parameters, wherein the one or more photoresist parameters characterize behavior of photoresist when the photoresist undergoes processing steps in the photolithography cluster, wherein the simulated diffraction signal was generated using one or more values of one or more profile parameters, and wherein the one or more values of the one or more profile parameters used to generate the simulated diffraction signal were derived from the one or more values of the one or more photoresist parameters associated with the simulated diffraction signal; and a metrology processor coupled to the optical metrology system and the photolithography cluster, wherein the metrology processor is configured to adjust one or more process parameters or equipment settings of the photolithography cluster based on the one or more values of the one or more photoresist parameters determined by the processor of the optical metrology system. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification