Electron and ion optical design software for integrated circuit manufacturing equipment A new concept for high throughput defect detection with multiple parallel electron beams is described. As many as 30 000 beams can be placed on a footprint of a in. 2 , each beam having its own microcolumn and detection system without cross-talk. Based on the International Technology Roadmap for Semiconductors requirements, some high level properties of the implementation of this concept were derived. A projection lens was designed that can both focus the primary beam into a small spot and simultaneously collect 75% of the secondary electrons. Conceptual design studies were performed for three crucial components of the detector chain: the scintillator, the light optics, and the detection array. The throughput of this concept is expected to be at least a factor of 300 higher than standard electron beam based defect detection systems.

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Emission models that form the basis of self-consistent fleld computations make use of the approximatÎon that emitted electrons form a smooth space charge jeily. In reality, electrons are discrete particles that are subject to statistical Coulomb interactions. A Monte Carlo simulation tool is used to evaluate the inftuence of discrete space charge effects on self-consïstent calculations of cathode-ray tube optics. We find that interactions in the space charge cloud affect the electron trajectories such that the velocity distribution is Maxwellian, regardless of the current density. Interactions near the emitter effectivety conserve the Max weflian distribution. The surpdsing resu]t is that the width of the distribution of transversal velocities does not change. The distribuûon of longitudinal velocities does broaden, as expected from existing theories.

Device shrinking combined with material manipulation under various process conditions becomes a difficult task if specific optimization conditions should be met. Nanolithography is limited by effects as line-edge and line-width roughness (LER and LWR respectively) and secondary electron blur (SEB). Simulation studies could show the direction of solving design for manufacturing problems. In the current article a simulation methodology is presented, based on the concept of stochastic modeling of exposure, material, and process aspects of lithography and pattern transfer with plasma etching in order to get information about the evolution of critical dimensions (CD), LER and LWR in the layout. The study reveals that under certain process conditions, the effect of acid diffusion on LER is more important than the one of SEB, although both deal with blurring, because acid diffusion is supposed to extend in longer radius. However, when resists of low degree of polymerization are used, SEB should also be considered explicitly since the deteriorations from blurring on both LER and CD are enhanced due to the graining nature of the material. In any case, etching smoothing effects of high frequency LER components should be considered in terms of CD loss.

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