High Sensitivity Resists for EUV Lithography: A Review of Material Design Strategies and Performance Results

Abstract

The need for decreasing semiconductor device critical dimensions at feature sizes below the 20 nm resolution limit has led the semiconductor industry to adopt extreme ultra violet (EUV) lithography with exposure at 13.5 nm as the main next generation lithographic technology. The broad consensus on this direction has triggered a dramatic increase of interest on resist materials of high sensitivity especially designed for use in the EUV spectral region in order to meet the strict requirements needed for overcoming the source brightness issues and securing the cost efficiency of the technology. To this direction both fundamental studies on the radiation induced chemistry in this spectral area and a plethora of new ideas targeting at the design of new highly sensitive and top performing resists have been proposed. Besides the traditional areas of acid-catalyzed chemically amplified resists and the resists based on polymer backbone breaking new unconventional ideas have been proposed based on the insertion of metal compounds or compounds of other highly absorbing at EUV atoms in the resist formulations. These last developments are reviewed here. Since the effort targets to a new understanding of electron-induced chemical reactions that dominate the resist performance in this region these last developments may lead to unprecedented changes in lithographic technology but can also strongly affect other scientific areas where electron-induced chemistry plays a critical role.

UV and VUV-induced fragmentation of tin-oxo cage ions

“…In particular, the photoresist is a potential issue, since high resolution patterning places tight restrictions on its lithographic performance. [1][2][3][4][5] The parameters resolution (minimum feature size that can be obtained), line edge roughness (average deviation of printed lines from a straight line), and sensitivity (light dose per unit of area that is required for pattern formation) are especially important. It is difficult to improve one of the resist parameters without simultaneously worsening at least one of the others, a problem that is known as the ''RLS trade-off''.…”

Line-Edge Roughness from Extreme Ultraviolet Lithography to Fin-Field-Effect-Transistor: Computational Study

“…and T are diffusion constant of acid, diffusion constant of base quenchers, rate constants of neutralization, rate constant of acid loss, rate constant of deprotection, concentration of base quenchers, concentration of protected unit, activation energy of acids, activation energy of quenches, activation energy of deprotection, ideal gas constant, time, and temperature, respectively [13,33]. For PEB process, equations (8-10) of acid and base quencher diffusion, deprotection reaction, and neutralization can reproduce experimental results [34,35]. When f LER is proportionality constant and m is normalized protected unit concentration, LER (≈ f LER /(dm/dx)) is proportional to protected unit fluctuation [36,37].…”

Multilayer Reflective Coatings for BEUV Lithography: A Review

“…X-ray optics is one of the key technologies in various scientific, engineering, and industrial applications. This technology has attracted intensive attention worldwide due to its importance [1][2][3][4]. Developing a local technological chain to design and manufacture high-reflective X-ray optical components is crucial for national economics and security.…”