High Resolution Negative Electron Research Articles

Functionalization dependence of the electron beam sensitivity for a conformationally immobile calix[6]arene resist

Calixarenes form a group of compounds that have been studied as high resolution negative electron beam resists. In this work, resists based on a conformationally immobile calix[6]arene molecule were synthesized and their sensitivities measured while the number of attached functional groups was systematically varied. This provided a direct test of the effect of the degree of functionalization on the electron beam resist sensitivity. The synthesis produced two basic molecular conformations: a cone conformer and a 1,2,3-alternate conformer. The number of attached allyl groups was deliberately varied from 0 to 8 allyls in steps of 2 allyls per synthesis. The resulting nine different resists were exposed and contrast curves were measured by atomic force microscopy. The least sensitive were the unfunctionalized calix[6]arenes with threshold doses of about 2 mC/cm2. The fully functionalized conformers had threshold doses around 0.1 mC/cm2. The sensitivities of both conformers were found to scale directly with th...

Poly(ether sulfone) as a negative resist for electron beam lithography

The sulfone containing polymer poly(butene sulfone) has long been used as positive electron beam resist due to the high scission rate of sulfone under electron irradiation. The authors demonstrate that poly(ether sulfone) acts as a high resolution negative electron beam resist which displays good chemical and dry-etch resistance. The electron beam exposure sensitivity at 10kV was found to be approximately 230μC∕cm2 for poly(ether sulfone), roughly 2.3 times that of poly(methyl methacrylate). As poly(ether sulfone) is a robust engineering polymer that can withstand etching this polymer is a suitable mask material and has properties of interest for direct incorporation in devices.

Comparison of high resolution negative electron beam resists

Four high resolution negative electron beam resists are compared: TEBN-1 from Tokuyama Corp. Japan, ma-N 2401XP and mr-L 6000.1XP from microresist technology GmbH Germany, and SU-8 2000 series from MicroChem Corp., USA. Narrow linewidth high density patterns are defined by 100kV electron beam lithography, and the pattern is transferred into silicon by a highly anisotropic SF6∕O2∕CHF3 based reactive ion etch process with a selectivity between silicon and the investigated resists of approximately 2. 20nm half-pitch lines and 10nm lines with a pitch down to 60nm are written and transferred into silicon.

Nanometer Electron Beam Lithography with Azide-Phenolic Resin Resist Systems

High resolution negative electron beam (EB) resists consisting of an aromatic azide and a phenolic resin have been developed for nanometer lithography. Bisazides which crosslink phenolic resins are more suitable for fine pattern fabrication than monoazides. Several phenolic resins such as novolak resin and polyhydroxystyrene were evaluated as resist matrix resins, and poly( p-hyroxystyrene) was selected as the best resin for nanofabrication. A resist composed of 3,3′-dimethoxy-4,4′-diazidobiphenyl and poly( p-hyroxystyrene) enables the definition of a 50 nm line-and-space pattern with an EB dose of 170 µ C/cm2 under optimum process conditions. The fine resist pattern obtained has sufficient dry etching resistance and can be applied to Si nanofabrication with good critical dimension control.

Fabrication of silicon nanostructures with a poly(methylmethacrylate) single-layer process

Poly(methylmethacrylate) has been found to act as a high resolution negative electron beam resist with sufficient dry-etch durability if acetone is used as a developer. We fabricated 10 nm silicon structures using the poly(methylmethacrylate) single-layer process and low temperature electron cyclotron resonance-type microwave-plasma etching without any additional complex processes.

Corrections to "A high resolution negative electron resist by image reversal"

A corrected figure 3 is presented for the above-named work (ibid., Vol. EDL-I, No. 10, October 1980).

A high resolution negative electron resist by image reversal

The use of AZ 1350 family photoresists as negative electron resists is described. Conventional photolithographic technology is used to coat and process the resist, with the exception of an e-beam exposure for patterning. A flood UV exposure is used for image reversal. Using 1.5 µm initial thickness, the exposure threshold for 6 s development in 1 : 1 AZ : H 2 O developer is 7 µC/cm2. The resist contrast under these conditions is 1.3; and the sensitivity is about 25 µC/cm2(70% thickness remaining). Useful resolution on SiO 2 /Si and Al/SiO 2 /Si substrates is demonstrated to be at least 0.5 µm, and the resist is shown to mask the plasma etching of Al.