Resist characteristics with direct write electron beam and SCALPEL exposure system

High acceleration voltage electron beam exposure is one of the possible candidates for post-optical lithography. The use of electrons, instead of photons, avoids optical related problems such as the standing wave issues. However, resists must conform to certain needs for the SCALPEL system, such as exposure in a vacuum chamber with 100kV electron beams. Taking into account the challenging requirements of high resolution, high sensitivity, low bake dependency and no outgassing, TOK has been able to develop resists to meet most of the SCALPEL system needs. However, due to the nature of chemical amplification and the FEB dependency, as is the case with DUV resists which varies for different features, we must recommend different resists for multiple features such as dense lines, isolated lines and contact holes. TOK has designed an electron beam negative resist, EN-009, which demonstrates 100nm pattern resolution. The dose to print on the SCALPEL system is 5.0 mu C/cm(2). The electron beam positive resist, EP-004M, has been designed for line and space patterns. The dose to print on the SCALPEL system is 8.25 mu C/cm(2). The processing conditions are standard, using 0.26N developer. These are the lowest exposure energies reported to date for similar resolution on this exposure tools.