CHARPAN

Charged Particle Nanotech

Project

Achievements in Tool Development

The PMLP proof-of-concept (POC) tool achieved “beam-on” in February 2007 and achieved resolution target of 25nm lines and spaces.

A PMLP (Projection Mask-Less Patterning) proof-of-concept (POC) tool has been built in the second project year (April 2006 – March 2007). Operating the system with Argon ions, “beam-on” has been achieved in February 2007: For the first time an electrostatic charged-particle projection optics with 200x reduction has been realized and is meeting specifications. First experiments were done using stencil masks in HSQ resist and then with resist-less direct patterning on Si, GaAs and glass surfaces and in Cr and MoSi layers.

Experiments showed that the resolution target of less than 25nm lines and spaces was achieved. As an example exposure results are shown in 20nm thick HSQ resist as obtained with 10keV Ar+ ions at an exposure dose of 5.6 µC/cm2.

Further, 22nm half pitch resolution was demonstrated with resistless direct patterning of 25nm MoSi hardmask layers on 70nm Cr covering a quartz mask blank using 10keV Ar+ ions at a sputtering dose of 9.34 mC/cm2. The ion beam patterned MoSi hardmask layer was found to be suitable for RIE pattern transfer into the 70nm Cr layer. Smaller patterns of 16nm and 11nm hp were structured within the 25nm MoSi layer.

Further resistless patterning experiments involving more complex patterns were carried out on silicon (left) and chromium surfaces (right image). A beam of 10keV Ar+ions at an exposure dose of 100 mC/cm2 was used for silicon, the exposure dose used for chromium was 39 mC/cm2. A 6nm singe line was realised in chromium.

Apart from the impressive resolution achieved, the 3D patterns realized on Si and GaAs surfaces showed nonometer depth precision. On top smoothness was outstanding.

An “APS Demo Unit” providing 4,000 beams with 22.5nm spot size was developed by FhG ISIT. A variety of resist patterns was realised. The example shows 45nm hp horizontal lines ending to the right in 30° and 60° lines, respectively. It was achieved in 20nm HSQ resist exposed with 10 keV Argon ions at 5.4 µC/cm2 exposure dose. [IMS, HSQ resist provided by IMS-CHIPS].

Complex patterns have been realised with resistless nanopattering on Si and GaAs surfaces using multipole induced positioning [IMS, AFM metrology: VTU]^[1] .

^[1]Elmar Platzgummer, Hans Loeschner and Gerhard Gross: "Projection Mask-Less Patterning (PMLP) for the fabrication of Leading Edge Complex Masks and Nanoimprint Templates", Oral Presentation: SPIE Photomask Technology (BACUS) Conference, Monterey, CA, USA, 2007 Sep 17-21.