Line edge roughness

When the minimum dimensions of a resist pattern are 100 nm, their dimensional tolerances approach the scale of the molecular components of the film. At this level, LER, random fluctuation in the width of a resist feature, may limit the advancement of lithography. Possible contribution to LER include polymer molecular weight, molecular weight distribution, molecular structure of resist components, inhomogeneity in component distribution within the film, statistical effects influencing film dissolution, intrinsic properties of the imaging, chemistry, image contrasts of irradiation, etc. 

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Linear-variable-differential-transformer (LVDT) transducers, 20 652-653 Linear velocity, exponents of dimensions in absolute, gravitational, and engineering systems, 8 584t Lineatin, 24 473 Line-block coders, 7 691 Line-edge roughness (LER), 15 181 Line exposures, in photography, 19 209-210 Linen... 

From these observations, a photooxidative scheme has been developed in which a hydrophobic resist becomes hydrophilic upon oxidation induced by deep UV (248 and 193 nm) radiation. Subsequent treatment with TiCLi followed by oxygen reactive ion etching then affords high-resolution, negative-tone patterns. Studies are currently underway to minimize the line edge roughness and background residue present in such patterns. 

Florinated norbomane ester monomers, (V), prepared by Harada et aL (2) were effective in resist compositions when processed by ArF lithography with advantages that included improved resolution, transparency, minimal line edge roughness, and etch resistance. 

Research Focus Synthesis of lactone containing positive resist copolymer compositions having improved line edge roughness resolution. 

Entry Postexposure Baked Temperature (°C) Optimum Exposure (mj / cm2) Maximum Resolution (nm) Mask Fidelity (nm) Line Edge Roughness (nm)... 

Laser ablation microprobe mass spectroscopy Low energy electron beam projection lithography Line edge roughness Maleic anhydride Methacrylic acid... 

Diaz, H. J. Tao, Y. C. Ku, A. Yen, and K. Young, An experimentally validated analytical model for gate line edge roughness (LER) effects on technology scaling, IEEE Electron Device Lett. 22(6), 287 (2001). 

Figure 14.24 Resolution capability of XP6627 EUV resist from Rohm and Haas, showing 25-nm and 30-nm dense (1 1) line/space features, with less than 2.5-nm line edge roughness and 3.5-nm line width roughness. Imaging was done on an EUV interferometric tool at Paul Scherrer Institute in Switzerland. (Courtesy of J. Thackeray.)...

Another type of balance that is struck in resist design for these advanced technology nodes concerns the trade-off between resolution, line edge roughness, and sensitivity. Empirical evidence shows that it is extremely difficult to... 

The spacer technique is unique in that with one lithographic exposure, the pitch can be reduced by a factor of two indefinitely, just with the application of a succession of spacer-formation and pattern-transfer processes. Furthermore, because spacer materials are mostly drawn from HM materials, their postetch pattern quality tends to be superior, especially in terms of line edge roughness and CD control, when compared to corresponding resist profiles after etch. It is also not sensitive to interlayer alignment. 

W. Lawrence, Spatial frequency analysis of line edge roughness in nine chemically related photo resists, Proc. SPIE 5039, 713 724 (2003) R. Brainard, P. Trefonas, J.H. Lammers, C.A. Cutler, J.F. Mackevich, A. Trefonas, and S.A. Robertson, Shot noise, LER and quantum efficiency of EUV photoresists, Proc. SPIE 5374, 74 85 (2004). 

T. Yamaguchi, H. Namatsu, M. Nagase, K. Kurihara, and Y. Kawai, Line edge roughness charac terized by polymer aggregates in photoresists, Proc. SPIE 3678, 617 (1999). 

Resolution - line edge roughness - sensitivity trade-off... 

The continuous miniaturization of devices in semiconductor industry emerges the need of lithographic materials that are sensitive and have low line-edge roughness (LER). To overcome... 

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