S.E. Huq

Sub10nm silicon field emitters produced by electron beam lithography and isotropic plasma etching

There is a growing interest in the fabrication of nanometer scale silicon tips for use as field emitters for that panel displays. Advantages include brightness, efficiency and spatial resolution. Additionally, field emission devices offer an alternative technology for high speed, radiation-resistant microcircuits operating over wide temperature ranges. This paper reports on a new fabrication route for producing arrays of silicon nanotips with precise control of tip size and geometry without any oxidation sharpening step.

Fabrication and characterisation of ultra sharp silicon field emitters

Abstract Ultra sharp single crystal 〈100〉 silicon emitters have been fabricated in gated configuration using a combination of high resolution electron beam lithography and plasma dry etching. High and stable emission currents have been obtained from individual and multi-tip arrays. Critical requirements of the microfabrication technique include etching of the silicon dioxide mask with near vertical walls and a high degree of control over the isotropic etching of the silicon to produce precise undercut profiles.

Electron beam lithography using chemically-amplified resist: resolution and profile control

The effect of post exposure bake and softbake conditions on the sensitivity of AZPN114 has been investigated experimentally. A bilayer system for undercut structures has been achieved using two layers of AZPN114 with different softbake temperatures. A single layer of AZPN114 has also been used to produce undercut and tailored resist profiles by two different multiple exposure strategies at different beam energies.

Design and fabrication of a micro optical system for x-ray analysis of biological cells

X-ray technology provides a number of powerful tools used in many different areas of science and industry. The ability to focus x-rays is the key to a wide range of applications including medicine (diagnosis and therapy), industrial applications (lithography and inspection), astronomy (space telescopes) and x-ray imaging (microscopy and analysis). This work presents the design and microfabrication of a novel x-ray micro optical system for use in an x-ray microprobe for analysis of biological cells. A reflective micro-optical system capable of focusing a wide range of wavelengths is at an advanced stage of development. The lens system consists of a pair of microfabricated optical elements, one of which has variable curvature providing a unique mechanically-actuated zoom focusing capability. Experiments have been carried out to measure the changes of the focal length (lens curvature) and sensor calibration.

Deep, three dimensional lithography with a laser-plasma x-ray source at 1nm wavelength

Abstract Soft x-rays with 1nm wavelength are used to print 48μm deep structures in chemically amplified resist. A multiple exposure/development technique reduces the x-ray exposure time to a total of 10min when using a compact, laser-plasma x-ray source. The use of an embedded mask generates a true three dimensional structure. Only 2μm thick x-ray masks are used with such soft x-rays. A 2.5THz waveguide cavity is fabricated using this novel process.

A systematic characterization of AZPN114 electron beam resist

Abstract Electron beam resists having high sensitivity and high resistance to dry etching are being investigated for sub-half micron device production using 5x reticle masks. Novolac based chemically amplified AZPN114 resist has been characterised at 20keV exposure under a range of dose, post-exposure bake, development and plasma etch conditions. A low voltage SEM metrology scheme based on the linear approximation technique for linewidth measurement has been adopted to monitor the in-process CD variability. Linewidth deviation of +/- 0.03um for 1.5um line features has been achieved for a dose of 2 . For high throughput mask production, 10keV exposures are being explored. Preliminary experimental results suggest that a dose ∼ 2uC/cm 2 is adequate without loss of CD controlability.

Chemically amplified AZPN114 electron beam resist for advanced photomask fabrication

Abstract Electron beam resists having high sensitivity and high resistance to dry etching are of interest generally for sub-half micron device production and in particular for e-beam fabrication of 5× masks and reticles. Novolac based chemically amplified AZPN114 resist has been characterised at 20 keV exposure using an EBMF 10.5 lithography system under a range of dose, post-exposure bake, development, wet chemical etch and plasma etch conditions. A low voltage SEM metrology scheme based on the linear approximation technique for linewidth measurement has been used to monitor the in-process CD variability. Linewidth deviation of +/- 0.03 μ for 1.5 μm line features has been achieved for a dose of 2 . For high throughput mask production, 10 keV exposures have been explored. Preliminary experimental results suggest that a dose ∼2 μC/cm 2 is adequate without loss of CD controllability.