Assessment of the critical dimension prediction accuracy for the lumped parameter model for resist lithography

David Fuard (1) , Patrick Schiavone (1)

1 LTM - Laboratoire des technologies de la microélectronique

Lithography modelling is widely used to predict the critical dimensions (CD) of patterned features after lithographic processing. A lot of full and simplified resist models are available. Previous works on full resist models have shown that the numerous model parameters are very difficult to set and often have a poor range of validity outside the dataset that have been used to generate them [Proc. SPIE 3678 (1999) 877; Proc. SPIE 4404 (2001) 99]. Simplified resist models are an alternative solution, easier to set, and they often provide a good simulation accuracy [Proc. SPIE 4691 (2002) 1266; Proc. SPIE 5040 (2003) 1536]. Among simplified models, lumped parameter model (LPM) is widely used for CD predictions. In this paper, we study the CD prediction accuracy of the LPM, using a comparison between experimental and simulated data. A systematic method is applied for LPM parameters extraction (contrast γ and effective thickness Deff). This assessment shows that a single parameter set giving reasonable accuracy is not found. Moreover, the critical analysis of the model parameters shows that these LPM parameters have a poor physical meaning. We also point out that there is a fundamental disagreement between the LPM theory and experiments.

Mots clés: Lumped parameter model; Simplified resist models; Bossung; Focus exposure matrix; Critical dimension; CD prediction; Simulation; Lithography

Domaines: Micro et nanotechnologies/Microélectronique

David Fuard, Patrick Schiavone. Assessment of the critical dimension prediction accuracy for the lumped parameter model for resist lithography. Microelectronic Engineering, 2004, 73-74, pp.53-58. ⟨10.1016/j.mee.2004.02.015⟩. ⟨hal-00021022⟩