Negative-tone Imaging with EUV Exposure

Abstract

Manipulation of dissolution properties by changing organic solvent developer and rinse material provides a novel technology to obtain fine pattern beyond the limitation of imaging system based on alkaline developer. QCM study showed no swelling character in negative-tone imaging (NTI) process even for current developer of n-butyl acetate (nBA). Actually, NTI process has shown advantages on resolution and line-width roughness (LWR) in loose pitch around 30 ~ 45 nm hp as a consequence of its non-swelling character. On the other hand, bridge and collapse limited its resolution below 20 nm hp, indicating that non-negligible amount of swelling still exists for tight pitch resolution. We investigated effects of solubility parameter of organic solvents on resolution below 20 nm hp. A bridge was reduced with a decrease in the solubility parameter p from nBA. On the other hand, much lower p caused film remaining due to its extremely slow Rmax. Based on these results, we newly developed FN-DP301 containing organic solvent with smaller p than nBA. Although rinse solvent gave negligible effects on bridge, there is a clear improvement on pattern collapse only in case of using new rinse solvent of FN-RP311.Lithographic performances of NTI process using nBA and FN-DP301 together with the other organic solvents were described in this paper under exposures with an E-beam and a EUV light. It is emphasized that 14 nm hp resolution was obtained only using FN-DP301 as a developer and FN-RP311 as a rinse under E-beam exposure. NTI showed 43% faster photospeed in comparison with PTI at 16 nm hp, indicating that NTI is applicable to obtain high throughput with maintaining resolution. In addition, sub-20 nm trench was obtained using NTI without bridge under EUV exposure, all of which are attributed to the low swelling character of NTI process. Similarly, NTI was able to print 20 nm dots using NXE:3100 with only a little peeling. Conversely CH patterning was significantly worse with NTI compared to PTI, that is, only 36 nm contacts with 60 nm pitch was resolved under EUV exposure.

Pattern collapse mitigation by controlling atmosphere during development process for semiconductor lithography

“…19,20) The effects of the developer on the pattern collapse have also been reported. 21,22) In this study, we focused on the differential pressure for the mitigation of pattern collapse. The differential pressure is proportional to σ as expressed by Eq.…”

Study on Preparation and Photolithography of Negative-work Photosensitive Polyester Acrylate

“…Furthermore, it is important to pattern the micro-circuit on the photosensitive material by photolithography process [7]. Generally, there are some factors like acid value of oligomer, exposure time, UV light intensity, type of developers, development time, hard baking temperature and so on, to influence the resolution of pattern [8][9][10]. In this study, we attempt to explore the pattern resolution of negative-work photosensitive polymer by regulating the solid content of polyester acrylate.…”

Analysis of stochastic effects in chemically amplified poly(4-hydroxystyrene-co-t-butyl methacrylate) resist

“…[7][8][9][10] A typical chemically amplified resist consists of a partially protected polymer, an acid generator, and a quencher. 11,12) In chemically amplified resists, an acid image is generated upon exposure to radiations. The deprotection of the partially protected polymer is induced by heating wafers after the exposure [ postexposure baking (PEB)].…”