An electron-beam microcolumn with improved resolution, beam current, and stability

Abstract

Articles you may be interested inThree-dimensional electron-beam lithography using an all-dry resist processWe have built and tested a 1 keV electron-beam microcolumn that focuses 1 nA of beam current into a 10 nm full width half-maximum beam diameter at a working distance of 1 mm. The electron source is a miniaturized Zr/O/W Schottky field emitter with 150 A/sr angular emission current density operating at about 1800 K at a distance of only 100 m from a silicon membrane extractor electrode. The actual microcolumn is 3.5 mm long assembled mainly from silicon membrane electrodes. Improved einzel lens design and fabrication allowed the operation of this beam focusing element in the accelerating mode. Spherical and chromatic aberrations were reduced by factors of about 2-3, respectively, as compared to the retarding lens mode. Excellent beam current stability with less than 1% variation over several hours has been observed.

Low-voltage electron beam lithography resist processes: top surface imaging and hydrogen silisesquioxane bilayer

“…In addition, the low voltages within the column make it particularly amenable for use in microcolumn form, allowing the design of multiple beam writing systems. [8][9][10] Charge-induced pattern distortion is a potential issue associated with low-voltage electron beam lithography, [11][12][13] although many ways exist to circumvent this issue by imaging near the crossover energy, or by altering the crossover energy of a resist film through the use of additives.…”

Studies of electron emitters for a miniaturized electron column design

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Effect of the subsidiary electrode in a newly developed source lens structure of the microcolumn

“…We compared two structural types of microcolumn. The first one is the conventional structure that composed of cathode, anode, extractor and limiter as illustrated in many other reports [8][9]. The other is the modified structure that has an additional electrode of subsidiary anode(S2s) between extractor and anode in the source lens.…”