The directed self-assembly (DSA) of block copolymers (BCP) is an emerging resolution enhancement tool that can multiply or subdivide the pitch of a lithographically defined chemical or topological pattern and is a resolution enhancement candidate to augment conventional lithography for patterning sub-20 nm features. Continuing the development of this technology will require an improved understanding of the polymer physics involved as well as experimental confirmation of the simulations used to guide the design process. Both of these endeavors would be greatly facilitated by a metrology, which is capable of probing the internal morphology of a DSA film. We have developed a new measurement technique, resonant critical-dimension small-angle X-ray scattering (res-CDSAXS), to evaluate the 3D buried features inside the film. This is an X-ray scattering measurement where the sample angle is varied to probe the 3D structure of the film, while resonant soft X-rays are used to enhance the scattering contrast. By measuring the same sample with both res-CDSAXS and traditional CDSAXS (with hard X-rays), we are able to demonstrate the dramatic improvement in scattering obtained through the use of resonant soft X-rays. Analysis of the reciprocal space map constructed from the res-CDSAXS measurements allowed us to reconstruct the complex buried features in DSA BCP films. We studied a series of DSA BCP films with varying template widths, and the internal morphologies for these samples were compared to the results of single chain in mean-field simulations. The measurements revealed a range of morphologies that occur with changing template width, including results that suggest the presence of mixed morphologies composed of both whole and necking lamella. The development of res-CDSAXS will enable a better understanding of the fundamental physics behind the formation of buried features in DSA BCP films.
Nanogel star polymers are developed as a new route for the formation of dual‐mode nanoparticle systems for applications in the areas of synergistic therapeutic delivery, imaged therapeutic delivery, and dual‐mode bioimaging agents. These extremely uniform, structurally versatile, water‐soluble, unimolecular organic nanoparticles with tunable polyvalency and functionality are preprogrammed to spontaneously upload different types of complex functional macromolecules.
A photomask design flow for generating guiding patterns used in graphoepitaxial DSA processes is proposed and tested. In this flow, a new fast DSA model is employed for DSA structure verification. The execution speed and accuracy of the fast model were benchmarked with our previously reported Monte Carlo method. We demonstrated the process window verification using the OPC/DSA flow with the fast DSA model and compared this with experimental results in the guiding patterns simulated by e-beam lithography.
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