Chen-Tai Liu

Characteristics performance of production-worthy multiple e-beam maskless lithography

E-beam direct write (EBDW) is one of the potential solutions for technology nodes of 28-nm half-pitch (HP) and beyond. Throughput limitation confined its development mostly to small-volume prototyping. Recently, proposals have been made to achieve throughput greater than 10 wafers per hour (WPH) on a single column with >10,000 beams writing in parallel (MEBDW), or even greater than 100 WPH by further clustering multiple columns within a typical production-tool footprint. The MAPPER concept contains a CMOS-MEMS blanker array driven by high-speed optical data path architecture to simultaneously control >10,000 beams, switching them on and off independently. The MAPPER Pre-Alpha Tool with a 110-beam, 5-keV column and a 300-mm wafer stage has been installed in a semiconductor manufacturing cleanroom environment and is ready for imaging test. In this paper, the resist imaging results of 110-beam parallel raster-scan writing for 30-nm half-pitch (HP) dense hole on 300-mm wafer is shown. The challenges of implementing multiple e-beam maskless lithography (MEBML2) in mass production environment, including resolution, local variation, focusing, energy latitude, proximity effect correction and electron scattering model fitting of hole patterning are discussed. Similar to mask-error-enhanced-factor (MEEF), the new writing-error-enhanced-factor (WEEF) to describe the impact of writing error, is introduced.