A series of new anionic PAGs, as well as PAG-bound polymers designed for use in 193 nm photoresist materials, have been synthesized and characterized. These novel materials provide optical transparency at 193 nm and also good etch resistance. PAG incorporated resists and PAG blended resists were exposed at a wavelength of 193 nm using an ASML 5500/950B optical lithography system with 0.63 NA. Exposed wafers were evaluated using SEM. The fluorine substituted PAG bound polymer and PAG blend resist provided a 110 nm (220 nm pitch) line/ space at 11.5, 13.0 mJ cm 22 , and 80 nm isolated features at 3 and 1 mJ cm 22 , respectively. The LER (3s) results showed that the fluorinated PAG bound polymer has LER values of 6.7 and 6.8 nm for isolated 80 nm and dense 110 nm lines, respectively, while the fluorinated PAG blend resist has LER values of 8.6 and 8.9 nm. The improvement may be due to the direct bonding of PAG into the polymer main-chain, which provides a more uniform distribution, thereby controlling acid diffusion and allowing a higher loading of PAG than the blend sample. The fluorine-free PAG bound or blend resists showed lower photospeed compared to photoresists based on fluorine-substituted PAGs.
Substantially improved photoresist material designs, which can provide higher photosensitivity and precise critical dimension and edge roughness control, will be required to enable the application of next generation lithography technology to the production of future sub-65 nm node IC device generations. The development and characterization of novel material platforms that solve the aforementioned basic problems with chemically amplified resists (CARs) is essential and is already one of the major subjects of modern lithography research. In that regard, we have pursued development of a variety of 193 nm and EUV CARs that contain photoacid generator (PAG) units covalently bonded directly to the resin polymer backbone. However, the detailed structure-property relationships that result from this direct attachment of the PAG functional group to the polymer have previously not yet been rigorously characterized. In this work, the lithographic properties of a polymer-bound PAG CAR (GBLMA-co-EAMA-co-F4-MBS.TPS) and its blended-PAG analog resist (GBLMA-co-EAMA blend F4-IBBS.TPS) were studied and compared. The direct incorporation of PAG functionality into the resist polymer, where the resulting photoacid remains bound to the polymer, showed improved photosensitivity, resolution, and lower LER as compared with the analogous blended-PAG resist. The improved resolution and LER were expected due to the restricted photoacid diffusion and uniform PAG distribution provided by direct incorporation of the PAG into the polymer backbone to make a single-component resist material. The ability to load higher levels of PAG into the resist provided by this PAG incorporation into the polymer, as compared to the low PAG concentrations attainable by traditional blending approaches, overcomes the sensitivity loss that should result from reduction in photoacid diffusivity and concomitant smaller acid-catalytic chain lengths. In fact, the polymer-bound PAG resist achieves a faster photospeed than the blended-PAG analog material under DUV radiation in the case of the materials reported here while still providing all of the aforementioned improvements such as the improved line edge roughness.
A series of new anionic PAGs, as well as PAG bound polymers designed for use in 193 nm photoresist materials have been synthesized and characterized. These novel materials provide optical transparency at 193 nm and also etch resistance. The fluorine substituted PAG bound polymer and PAG blend resist provided 110 nm (220 nm pitch) line/space at 11.5, 13.0 mJ/cm 2 , and 80 nm isolated features at 3, 1 mJ/cm 2 , respectively. The LER (3σ) results showed the fluorinated PAG bound polymer have LER values 6.7 nm and 6.8 nm for isolated 80 nm and dense 110 nm lines respectively, which were lower than the PAG Blend polymers
Previously, we demonstrated an all dry, selective laser ablation development in methyl acetoxy calixarene (MAC6) which produced high resolution (15-25 nm half-pitch), high aspect ratio features not achievable with wet development. In this paper, we investigate the selective laser ablation process as a means to create a block copolymer derived lithographic pattern through the selective removal of one block. Two block copolymer systems were investigated PS-b-PHOST, and P2VP-b-PS-b-P2VP. The selective laser ablations process on block copolymers offers an alternative to plasma etching when plasma etching is not effective.
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