TY - JOUR AU - Parfeniukas, Karolis AU - Rahomäki, Jussi AU - Giakoumidis, Stylianos AU - Seiboth, Frank AU - Wittwer, Felix AU - Schroer, Christian AU - Vogt, Ulrich TI - Improved tungsten nanofabrication for hard X-ray zone plates JO - Microelectronic engineering VL - 152 SN - 0167-9317 CY - [S.l.] PB - Elsevier M1 - PUBDB-2016-05566 SP - 6 - 9 PY - 2016 AB - We present an improved nanofabrication method of high aspect ratio tungsten structures for use in high efficiency nanofocusing hard X-ray zone plates. A ZEP 7000 electron beam resist layer used for patterning is cured by a second, much larger electron dose after development. The curing step improves pattern transfer fidelity into a chromium hard mask by reactive ion etching using Cl2/O2 chemistry. The pattern can then be transferred into an underlying tungsten layer by another reactive ion etching step using SF6/O2. A 630 nm-thick tungsten zone plate with smallest line width of 30 nm was fabricated using this method and characterized. At 8.2 keV photon energy the device showed an efficiency of 2.2 LB - PUB:(DE-HGF)16 UR - <Go to ISI:>//WOS:000385991400002 DO - DOI:10.1016/j.mee.2015.12.015 UR - https://bib-pubdb1.desy.de/record/315025 ER -