In order to meet the growing demand of the electronics industry for smaller, higher resolution features much recent attention has focused on next generation lithographic techniques, such as Extreme Ultraviolet (EUV) or e-beam lithography. Complementary to this field of research is the design of the next generation of photoresists to produce sub 50 nm feature sizes. Chemically amplified molecular glass resists are among the most promising alternatives to traditional polymeric materials. These materials are monodisperse, amorphous organic molecules which lead to high resolution patterns with low line edge roughness owing to their small size and lack of chain entanglement. In this submission, we describe our work in the development of molecular glass resists. The materials are designed with rigid cores, to ensure high T<sub>g</sub>, and with bulky side groups to inhibit crystallization. We show that these materials are capable of producing high resolution feature sizes and show great promise in meeting the demands of emerging next-generation lithographic techniques.
The demands for high resolution and issues of line edge roughness require a reconsideration of current resist design strategies. In particular, EUV lithography will provide an opportunity to examine new resist concepts including new elemental compositions and low molar mass resists or molecular resists. In the former case, resist compositions incorporating elements such as silicon and boron have been explored for EUV resists and will be described. In an example of the latter case, molecular glass resists have been designed using synthetic architectures in globular and core-arm forms ranging from one to multiple arms. Moreover, our studies include a series of ring and irregularly shaped small molecules modified to give imaging performance. These materials have been explored to improve line edge roughness (LER) compared to common polymer resists. Several examples of polymeric and molecular glass resists will be described. Several compositions showed high glass transition temperatures (T<sub>g</sub>) of ~ 120°C and possessed no crystallinity as seen from XRD studies. Negative-tone molecular glass resists with a T-shaped phenolic core structure, 4-[4-[1,1-Bis(4-hydroxyphenyl)ethyl]]-α,α-dimethylbenzylphenol, have demonstrated feature sizes as small as 50mn. Similarly, negative-tone images made using spiro-based compounds showed feature size as small as 60nm in lines/space patterns using e-beam lithography. Most recently we have demonstrated that fully and partially <i>tert</i>-butoxycarbonyl (<i>t</i>-Boc) protected calixresorcinarene derivatives can be successfully studied as a positive-tone resist using EUV and E-beam lithography. Resolution as low as 35nm was obtained by EUV exposure.