Articles you may be interested inLowdistortion electronbeam lithography for fabrication of highresolution germanium and tantalum zone plates J. Vac. Sci. Technol. B 13, 2762 (1995); 10.1116/1.588261Highperformance multilevel blazed xray microscopy Fresnel zone plates: Fabricated using xray lithography Soft Xray nano lithography of semitransparent masks for the generation of highresolution high contrast zone plates AIP Conf.

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Summary:We present a three-dimensional simulation of scanning electron microscope (SEM) images and surface charging. First, the field above the sample is calculated using Laplace's equation with the proper boundary conditions; then, the simulation algorithm starts following the electron trajectory outside the sample by using electron ray tracing. When the electron collides with the specimen, the algorithm keeps track of the electron inside the sample by simulating the electron scattering history with a Monte Carlo code. During this phase, secondary and backscattered electrons are emitted to form an image and primary electrons are absorbed; therefore, a charge density is formed in the material. This charge density is used to recalculate the field above and inside the sample by solving the Poisson equation with the proper boundary conditions. Field equation, Monte Carlo scattering simulation, and electron ray tracing are therefore integrated in a self-consistent fashion to form an algorithm capable of simulating charging and imaging of insulating structures. To maintain generality, this algorithm has been implemented in three dimensions. We shall apply the so-defined simulation to calculate both the global surface voltage and local microfields induced by the scanning beam. Furthermore, we shall show how charging affects resolution and image formation in general and how its characteristics change when imaging parameters are changed. We shall address magnification, scanning strategy, and applied field. The results, compared with experiments, clearly indicate that charging and the proper boundary conditions must be included in order to simulate images of insulating features. Furthermore, we shall show that a three-dimensional implementation is mandatory for understanding local field formation.

A hard x-ray imaging microscope based on a phase zone plate has been developed and tested. The zone plate, with a 5 cm focal length and a 0.2 pm smallest linewidth, was used to image 8 keV x rays from the samples. The imaging microscope can be used to obtain nearly diffraction-limited resolution over the entire imaging field, and its resolution is almost independent of source size and source motions. We have tested such an imaging microscope, and a resolution of about 0.4 pm was obtained. The images were obtained with an exposure time of less than 1 min, for a magnification factor of 30 in the x rays. The x rays were then converted into visible light, and another 7 times magnification were obtained by using a lens system coupled to a charge coupled device camera. The results from the imaging microscope, and possible applications, will be discussed. 0 1995 American Institute of Physics.-1NTRODUCTlON

The system concepts used in a novel approach for a high throughput maskless lithography system called reflective electron beam lithography (REBL) are described. The system is specifically targeting five to seven wafer levels per hour throughput on average at the 45nm node, with extendibility to the 32nm node and beyond. REBL incorporates a number of novel technologies to generate and expose lithographic patterns at estimated throughputs considerably higher than electron beam lithography has been able to achieve as yet. A patented reflective electron optic concept enables the unique approach utilized for the digital pattern generator (DPG). The DPG is a complementary metal oxide semiconductor application specific integrated circuit chip with an array of small, independently controllable metallic cells or pixels, which act as an array of electron mirrors. In this way, the system is capable of generating the pattern to be written using massively parallel exposure by ∼1×106 beams at extremely high data rates (∼1Tbit∕s compressed data). A rotary stage concept using a rotating platen carrying multiple wafers optimizes the writing strategy of the DPG.

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Multiaxis and multibeam technology for high throughput maskless E-beam lithography J. Vac. Sci. Technol. B 30, 06FC01 (2012); 10.1116/1.4767275 High-current electron optical design for reflective electron beam lithography direct write lithography J. Vac. Sci. Technol. B 28, C6C1 (2010); 10.1116/1.3505130 REBL: A novel approach to high speed maskless electron beam direct write lithographyReflective electron beam litography ͑REBL͒ utilizes several novel technologies to generate and expose lithographic patterns at throughputs that could make ebeam maskless lithography feasible for high volume manufacturing. The REBL program was described in a previous article ͓P. Petric et al., J. Vac. Sci. Technol. B 27, 161 ͑2009͔͒ 2 years ago. This article will review the system architecture and the progress of REBL in the past 2 years. The main technologies making REBL unique are the reflective electron optics, the rotary stage, and the dynamic pattern generator ͑DPG͒. Changes in how these concepts have been implemented in a new design will be discussed. The main disadvantage of today's electron beam direct write is low throughput; it takes many tens of hours to expose a 300 mm wafer today using ebeam lithography. The projected system throughput performance with the integrated technology of the reflective optics, DPG, and a multiple wafer rotary stage will be shown incorporating the performance data for the new column design. C6C10 Petric et al.: Reflective electron beam lithography: A maskless ebeam direct write lithography C6C10 J.

Electron beam lithography is used to fabricate two-metal electrode tip-shaped structures. The distance between the tips is continuously controlled to be between 5 and 70 nm. The electron beam lithography process is robust and the tip separation is well controlled in the sense that the smallest distance between the tips is a consequence of the design and not a consequence of randomly distributed metal spots around the tip area. Interest in these structures is due to the fact that they can be used to fabricate rectifiers, working with single molecule, designed to exhibit semiconductor properties.