In order to truly represent photolithography through simulation, the exposure, bake and development models and model parameters must be accurate. Models for the pre-bake, exposure, post-exposure/pre-development bake, and the development have been developed and are available with most commercial simulators.15 The extraction of the exposure parameters has been established.13 However, the extraction of the bake and development model parameters have been subject to question'3 given the immersion type development that has been required for the measurement of the development rate and henceforth the extraction of these parameters. Using the approach for the measurement of the in-situ development rate, developed in the first paper of this two paper series, the model parameters were extracted for Shipley 812 resist with Shipley MF312 developer. Development rates for exposures of 66, 90 and ll4rnJ/cm2 were measured. It was discovered that the set of Kim model parameters, R1 through R, were highly correlated with the combination of the Dill exposure parameters. Thus, for A=O.581pin', B=O.O82im1, C=O.013cm2/mJ, the parameters R1=25.559micrometers/min, R2=1O.45lmicrometersm/min, R3=1.879, R4=O.1l2, R5=1.586, R,=0.000micrometers, and a=O.OO16im were extracted. A comparison of simulated data using the extracted model parameters with the measured data demonstrated the quality of the fit.
Date of creation, presentation, or exhibit
Department, Program, or Center
Microelectronic Engineering (KGCOE)
Patrick G. Drennan, Bruce W. Smith, "Extraction of process specific photolithography model parameters", Proc. SPIE 2196, Integrated Circuit Metrology, Inspection, and Process Control VIII, (1 May 1994); doi: 10.1117/12.174146; https://doi.org/10.1117/12.174146
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