87 research outputs found
Helium ion beam lithography on fullerene molecular resists for sub-10 nm patterning
Get PDFHelium ion beam lithography (HIBL) is an emerging technique that uses a sub-nanometre focused beam of helium ions generated in the helium ion microscope to expose resist. It benefits from high resolution, high sensitivity and a low proximity effect. Here we present an investigation into HIBL on a novel, negative tone fullerene-derivative molecular resist. Analysis of large area exposures reveals a sensitivity of ~40 µC/cm2 with a 30 keV helium beam which is almost three orders of magnitude higher than the sensitivity of this resist to a 30 keV electron beam. Sparse line features with line widths of 7.3 nm are achieved on the ~10 nm thick resist. The fabrication of 8.5 half-pitched lines with good feature separation and 6 nm half-pitched lines with inferior but still resolvable separation is also shown in this study. Thus, sub-10 nm patterning with small proximity effect is demonstrated using HIBL using standard processing conditions, establishing its potential as an alternative to EBL for rapid prototyping of beyond CMOS devices
Charged particle single nanometre manufacturing
Get PDFFollowing a brief historical summary of the way in which electron beam lithography developed out of the scanning electron microscope,three state-of-the-art charged-particle beam nanopatterning technologies are considered. All three have been the subject of arecently completed European Union Project entitled “Single Nanometre Manufacturing: Beyond CMOS”. Scanning helium ionbeam lithography has the advantages of virtually zero proximity effect, nanoscale patterning capability and high sensitivity in combinationwith a novel fullerene resist based on the sub-nanometre C60 molecule. The shot noise-limited minimum linewidthachieved to date is 6 nm. The second technology, focused electron induced processing (FEBIP), uses a nozzle-dispensed precursorgas either to etch or to deposit patterns on the nanometre scale without the need for resist. The process has potential for highthroughput enhancement using multiple electron beams and a system employing up to 196 beams is under development based on acommercial SEM platform. Among its potential applications is the manufacture of templates for nanoimprint lithography, NIL. Thisis also a target application for the third and final charged particle technology, viz. field emission electron scanning probe lithography,FE-eSPL. This has been developed out of scanning tunneling microscopy using lower-energy electrons (tens of electronvoltsrather than the tens of kiloelectronvolts of the other techniques). It has the considerable advantage of being employed without theneed for a vacuum system, in ambient air and is capable of sub-10 nm patterning using either developable resists or a self-developingmode applicable for many polymeric resists, which is preferred. Like FEBIP it is potentially capable of massive parallelizationfor applications requiring high throughput
Spin-on-carbon hard masks utilising fullerene derivatives
Get PDFSpin-on-Carbon (SoC) hardmasks are an increasingly key component of the microchip fabrication process. Progress in lithographic resolution has made the adoption of extremely thin photoresist films necessary for the fabrication of “1x nanometre” linewidth structures to prevent issues such as resist collapse during development. While there are resists with high etch durability [1], ultimately etch depth is limited by resist thickness. A possible solution is the use of a multilayer etch stack. This allows for considerable increase in aspect ratio. For the organic hard mask base layer, a carbon-rich material is preferred as carbon possesses a high etch resistance in silicon plasma etch processes. A thin silicon topcoat deposited on the carbon film can be patterned with a thin photoresist film without feature collapse, and the pattern transferred to the underlying carbon film by oxygen plasma. This produces high aspect ratio carbon structures suitable for substrate etching. In terms of manufacturability it is beneficial to spin coat the carbon layer instead of using chemical vapor deposition [2], but the presence of carbon-hydrogen bonds in typical spin-on-carbon leads to line wiggling during the etch (a significant problem at smaller feature sizes). We have previously introduced a fullerene based SoC and reported on material characterization [3,4,5]. The materials low Ohnishi number provides high etch durability and the low hydrogen level allows for high resolution etching without wiggling. The use of the materials in such etch stacks is demonstrated (figures 1-3). A 20nm thin silicon film was sputtered on top of the carbon layers. Resist patterns are defined by e-beam, and in the case of figure 2, EUV lithography and transferred to the silicon thin film using SF6/CHF3 etch chemistry. The carbon layer was then etched by O2 plasma using the silicon mask and finally the pattern was transferred into the silicon substrate using the same process used to etch the topcoat. Recent advances in material development and work towards commercialization of the materials will be reported. Some results from external evaluations of the original 100 series will be presented, together with recent developments with the newer 200 and 300 series formulations (offering improved thermal stability and etch durability).
[1] J. Manyam, M. Manickam, J.A. Preece, R.E. Palmer, and A.P.G. Robinson, Proc. SPIE 7972 (2011) 79722N.
[2] C.Y. Ho, X.J. Lin, H.R. Chien, C. Lien, Thin Solid Films 518 (2010) 6076
[3] A. Frommhold, J. Manyam, R.E. Palmer, and A.P.G. Robinson, Proc. SPIE 8328 (2012) 83280U
[4] A. Frommhold, R.E. Palmer, and A.P.G. Robinson, J. Micro/Nanolith. MEMS MOEMS. 12 (3), 033003 (2013)
[5] A Frommhold, A G. Brown, T Lada, A P. G. Robinson, Proc SPIE 9421-21 (2015
A Fullerene-platinum Complex for Direct Functional Patterning of Single Metal Atom-embedded Carbon Nanostructures
Get PDFThe development of patterning materials (“resists”) at the nanoscale involves two distinct trends: one is toward high sensitivity and resolution for miniaturization, the other aims at functionalization of the resists to realize bottom-up construction of distinct nanoarchitectures. Patterning of carbon nanostructures, a seemingly ideal application for organic functional resists, has been highly reliant on complicated pattern transfer processes because of a lack of patternable precursors. Herein, we present a fullerene–metal coordination complex as a fabrication material for direct functional patterning of sub-10 nm metal-containing carbon structures. The attachment of one platinum atom per fullerene molecule not only leads to significant improvement of sensitivity and resolution but also enables stable atomic dispersion of the platinum ions within the carbon matrix, which may gain fundamentally new interest in functional patterning of hierarchical carbon nanostructures
Alternative resist approaches
No full textAs the challenges of next generation lithography have increased it has become increasingly difficult to maintain progress with traditional photoresists. A substantial research effort in to nonconventional approaches for extreme ultraviolet (EUV) resist materials is now underway. In this chapter a variety of approaches including resists with low, or with high, EUV absorbance, and resists formulated from organic-metal oxides and organic-nanoparticle composites are examined.</p
Overview of Materials and Processes for Lithgography
No full textComputers and other electronic devices are an integral and ubiquitous part of the modern world. One of the key drivers for the development, power, cost, and availability of these devices is the procedure known as lithography where the circuit pattern is written on the chip at the micrometer and nanometer length scale. This chapter provides an overview of the materials and processes that are involved in lithography. The various different lithographic exposure tools are reviewed and their capabilities are discussed along with comparisons of the advantages and disadvantages of each. The key material in lithography is the resist or photoresist. Resist figures of merit are defined and their importance is elaborated. The array of different resist families and types used historically, currently, and those under development are reviewed along with their benefits and weaknesses. Finally, some of the specific challenges and difficulties facing future resist materials and processes are discussed
Negative-tone organic molecular resists
No full textNegative-tone molecular resists are organic small molecule resists that can be lithographically patterned in the negative tone. This chapter examines a wide variety of different resists of this type that have been developed and investigated including fullerene, triphenylene, calixarene, noria, and polyphenol-based resists along with other unique compounds. A review of the chemistry and physics of cationic polymerization and cross-linking of functional groups such as epoxides and oxetanes is also included, as this approach is used in many different resist designs. Resolution below 20 nm has been reported in a number of different designs in extreme ultraviolet and electron beam, and isolated lines of 10 nm and below are seen in some resists with electron beam patterning. Negative-tone molecular resists have shown good combinations of resolution, sensitivity, and line-edge roughness and continue to hold promise for use in the next generation lithography.</p
- …
