Olaf Fortagne

Large-field particle beam optics for projection and proximity printing and for maskless lithography

Recent studies have shown the utility of ion projection lithography (IPL) for the manufacturing of integrated circuits. In addition, ion projection direct structuring (IPDS) can be used for resistless, noncontact modification of materials. In cooperation with IBM Storage Technology Division, ion projection patterning of magnetic media layers has been demonstrated. With masked ion beam proximity techniques, unique capabilities for lithography on nonplanar (curved) surfaces are outlined. Designs are presented for a masked ion beam proximity lithography (MIBL) and masked ion beam direct structuring (MIBS) tool with sub-20-nm resolution capability within 88-mm□ exposure fields. The possibility of extremely high reduction ratios (200:1) for high-volume projection maskless lithography (projection-ML2) is discussed. In the case of projection-ML2 there are advantages of using electrons instead of ions. Including gray scaling, an improved concept for a ⩽50-nm projection-ML2 system is presented with the potential to meet a throughput of 20 wafers per hour (300 mm).

Projection maskless lithography

Recent studies have shown the feasibility of Projection Mask-Less Lithography (PML2) for small and medium volume device production (2-5 WPH) for the 45nm technology node. This PML2 tool concept comprises a combined electrostatic-magnetic electron optical column with 200x de-magnification factor. Instead of a mask there is a programmable aperture plate enabling dynamic beam structuring. Wafer exposure is done stripe-by-stripe with a scanning 300mm wafer stage. Detailed calculations of the PML2 optical column (2-step demagnification) including Monte-Carlo simulations of Coulomb interactions are presented. The extendibility of PML2 technology for the 32nm node will be discussed.

Shaped beam technology for nano-imprint mask lithography

the Leica SB350MW 50keV shaped-beam e-beam lithography tool was used to write large-area 1X templates applicable in Step and Flash Imprint Lithography (S-FIL). This paper describes how information from the pattern analysis can be used to define the ZEP7000 resist exposure optimization technique for the SB350 MW tool together with the Motorola template pattern transfer process to obtain final template images in the transparent template. As a result of the complete process, well-resolved trenches measuring 33 nm and contacts as small as 44nm were obtained. Further improvements in the resist patterning will be possible by an adaptation of our standard proximity corrector (currently used in the 90 nm node maskmaking) with a high resolution upgrade.

ZBA31: an advanced mask writer meeting the demands of the 1-gigabit DRAM generation

It is now widely accepted that variable shaped beam ( VSB ) writers have some significant advantages compared to the gaussian principle systems, especially when throughput is considered. The ZBA variable shaped beam system introduced in this paper is the most advanced mask generator from Jenoptik Germany. We have utilized the VSB electron optical concept from the very beginning of designing e-beam systems of the ZBA-series more than 20 years ago. The unique combination of this longstanding experience, more than 120 systems were constructed and comissioned, with some very recent developments in the software and operation logistics of the system, allow the ZBA31H maskwriter system to provide the complete performance that is required to satisfy the demands of the 1 G-DRAM generation masks.