21 July 2000 Overview of the ion projection lithography European MEDEA and international program
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Ion Projection Lithography (IPL) follows the same principle as optical wafer steppers when using hydrogen or helium ions for the reduction printing of stencil mask patterns to wafer substrates: (1) DUV resists can be used with ion beam exposure; (2) well established optical wafer alignment techniques are used; (3) the mask is stable during exposure. IPL is the only NGL technique where the mask is not scanned during exposure. Because of the very small particle wavelength (5 * 10-5 nm for 100 keV He+ ions there is the possibility of using electrostatic ion-optics with very small numerical aperture (NA approximately equals 10-5). The ion-optics is based on aluminum lens electrode and standard insulator materials. Mechanical tolerances on lens electrode manufacturing and adjustment are in the micrometer range because of in-situ electronic column fine adjustment possibilities. Wafer stage movements with micrometer precision is sufficient through feedback from precise laser interferometer stage position measurements to electronic image placement of the ion image projected to the wafer with on-line 'pattern lock' control. As part of the MEDEA project an IPL process development tool (PDT) is being integrated by IMS with the target to achieve 50 nm resolution within a 12.5 mm exposure field. The IPL production stepper will be based on a similar but more compact ion-optical column, exposing large (e.g. 25 mm) chip fields by stitching of 12.5 mm fields. A 300 mm wafer throughput of 30 WPH is feasible also for the 50 nm node. IPL has the potential of achieving the lowest NGL cost of ownership with the longest multi-generational life time. The practical resolution limit of the IPL technique is below 35 nm.
© (2000) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Rainer Kaesmaier, Rainer Kaesmaier, Hans Loeschner, Hans Loeschner, } "Overview of the ion projection lithography European MEDEA and international program", Proc. SPIE 3997, Emerging Lithographic Technologies IV, (21 July 2000); doi: 10.1117/12.390063; https://doi.org/10.1117/12.390063


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