Contrast improvement with balanced diffusion control of PAG and PDB

Abstract

For semiconductor manufacturing of k 1 <0.3 half pitch, immersion lithography is still indispensable for process development and production. As the minimum feature size reaches the resolution limit, many resolution enhancement techniques and processes are developed to meet the stringent imaging requirements. Since the optical contrast is not sufficient for low-k 1 application, the optimizing conditions for DOF, MEEF, LWR, 2D features, top-view profile, and defect become more challenging than ever for manufacturing. The low-k 1 induced poor ADI (after development inspection) end-to-end profile is deleterious to pattern fidelity that may further impact the AEI (after etching inspection).From a previous study, the photo-decomposed base (PDB) has been proven effective in enhancing the resist contrast and improving the DOF from conventional quenchers. In this paper, we study its further improvement on litho performance by controlling the diffusion lengths of the PAG and the PDB. We split the polarity and size of the PAG and PDB to control the diffusion length. The top view profile is improved from rounding to vertical if a longer diffusion length of the PDB is selected. The scattering bar printing window can also be improved in such a condition. If the PAG and the PDB have better matching controls, the MEEF, LWR, CDU, and end-to-end top view profile are improved as shown in Fig.1. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/21/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspxFig. 1. SEM top view profile is improved from left to right with optimum PAG and PDB diffusion lengths. (From Resist 2 to Resist 9 in our article)

Progress in resolution, sensitivity, and critical dimensional uniformity of EUV chemically amplified resists

“…9 The addition of PDB to the resist formulation improves the photoacid gradient at the image line edge leading to higher contrast resist material. With the combination of low acid diffusion coupled with higher contrast, large improvement in resolution, LWR and contact hole CDU can be seen.…”