Programmable Aperture Plate System Research Articles

Projection Charged Particle Nanolithography and Nanopatterning

The projection charged particle multi-beam techniques of IMS Nanofabrication are based on illuminating a programmable aperture plate system [APS; consisting of an aperture plate and a blanking plate with integrated complementary metal–oxide–semiconductor (CMOS) electronics] with a telecentric broad beam, to separate this beam into thousands of micrometer sized beams and to demagnify the beamlets thus formed to nanometer dimensions, using a projection charged particle optics with 200× reduction. Only beams which are unaffected by the blanking plate are projected to the substrate whereas beams which are slightly deflected are filtered out at a contrast aperture at the second cross-over of the projection optics. Proof-of-concept test systems were realized for these techniques. Inserting a 43k-APS providing 43 thousand programmable 12.5 nm sized beams complex patterns were realized in 20 ×20 µm2 exposure fields when using 10 keV H3+ ions. For the electron multi-beam test system the beam at the APS was limited to 2 mm diameter, thus realizing 2500 programmable electron beams of 12.5 nm size and 50 keV energy within an exposure field of ca. 7 ×7 µm2. Application fields of projection charged particle multi-beam techniques are CHARPAN (Charged Particle Nanopatterning, with ion multi-beams), PML2 (Projection Mask-Less Lithography), and eMET (electron Mask Exposure Tool).

Charged Particle Nanopatterning (CHARPAN) of 2D and 3D masters for flexible replication in Substrate Conformal Imprint Lithography (SCIL)

Recently, the first generation programmable Aperture Plate System with integrated CMOS electronics (CMOS-APS) featuring 43 thousand switchable beams has been inserted into a Charged Particle Nanopatterning (CHARPAN) tool. Using this configuration, the first (2D) exposure results in Hydrogen Silsesquioxane (HSQ) resist, employing 10 keV Hydrogen ion ( H 3 + ) parallel beams of 12.5 nm spot size, show that (at least) a 20 nm resolution is feasible in this system. These CHARPAN patterns have been used as masters for PDMS stamp casting. The flexible PDMS stamps have been implemented in Substrate Conformal Imprint Lithography (SCIL™). The original 20 nm resolution features have also been observed in the imprinted sol–gel material. The CHARPAN tool can be operated with heavier ions (Ar +, Xe +) as well, enabling maskless and resistless 3D nanopatterning. Here again, a flexible PDMS stamp has been cast and these deep 3D structures have been successfully applied in SCIL. The combination of CHARPAN and SCIL opens up new possibilities for low cost, fast and flexible 2D and 3D manufacturing of nano-devices.

Projection maskless patterning for nanotechnology applications

Projection maskless patterning (PMLP) is based on a programmable aperture plate system and on charged particle projection optics with 200× reduction, providing thousands of electron or ion (H+, He+, Ar+, Xe+, C60−) beams working in parallel on the substrate. As part of the European CHARPAN project a PMLP proof-of-concept tool has been realized. Using resolution templates, with 10keV H+ multibeams a resolution of 16nm lines and spaces was achieved in HSQ resist across the proof-of-concept tool 25×25μm2 exposure field at an exposure dose of 25μC∕cm2. Enhancing the dose by 10% there was <1nm increase in linewidth. With 10keV Ar+ multibeams resistless nanopatterning of various materials was accomplished. Inserting a wired programmable aperture plate system providing ∼4000 beams, first HSQ resist exposure and patterning results have been accomplished, implementing gray scale exposure techniques. The system is being upgraded to a PMLP engineering tool integrating an aperture plate system with complementary metal oxide semiconductor electronics providing ∼40000 programmable beams, a precursor gas injection system for in situ ion multibeam induced etching and deposition, and a laser-interferometer controlled high-precision vacuum stage. Industrial PMLP nanotechnology applications are discussed.