Fundamental limits to EUV photoresist

Abstract

Recent experimental results indicate that current resists lack the ability to simultaneously meet the 2005 International Roadmap for Semiconductors (ITRS) goals for Resolution, Line Edge Roughness (LER) and Sensitivity (RLS). This RLS tradeoff has also been demonstrated through modeling work. Here we use a model to explore the impact on the RLS tradeoff of anisotropic acid diffusion and increased quantum yield. We show that both these effects can significantly improve the RLS tradeoff.

Understanding Extreme Stochastic Events in EUV Resists

“…If we simply assume the dose noise to go as the square root of the mean dose, a 25% reduction in noise would require a 56% increase in dose. This arguably represents the "shot noise limit" [8][9][10][11][12][13][14][15][16][17][18][19]], yet we find that by biasing the CD by 2 nm we significantly outperform this "limit". Figure 11 shows the corresponding PDFs for the original case in Fig.…”

“…Before directly using this new error propagation function we must also determine the new effective dose noise. Based on the fact that we decreased the resist blur one should expect the effective dose noise to increase in accordance to the well documented tradeoff between resolution and noise [9][10][11]. Repeating the stochastic modeling and analysis processes described above for this new case yields the PDF results in Fig.…”

Recent Progress in EUV Resist Outgas Research at EIDEC

“…The trade-off relationship among resolution, line width roughness (LWR), and sensitivity is a problem in the development of EUV resists [1]. Resist outgassing is one more major challenge in realizing EUVL, because it probably contributes to the contamination of the EUV mirror optics, resulting in reflectivity loss.…”

Progress Towards Production Worthy EUV Photoresists: Balancing Litho, Outgassing and OOB Performance

“…[7] The RLS tradeoff for L/S patterns has been known for several years and continues to be challenging. [7] Recently, the corresponding RCS relationship for contact holes (C/H) where LWR is replaced with the critical dimension uniformity (CDU) term has received a lot of attention. [8,9] The next materials related issue is outgassing.…”