This course presents an overview of the DUV lithography utilizing 157-nm light. The course gives an insight of the status of this technology, its limitations, and its applicability to several generations of IC's. A brief review of the physical principles of optical lithography is presented, and components of the manufacturing system are discussed in some detail. Topics to be covered include: 157-nm lithography system requirements; lithography tool modules such as laser illumination system (including source, beam delivery module, and module forming illumination of desired type and spatial coherence), projection optics system; reticles, pellicles, nitrogen ambience and resists. The discussion addresses specificity (birefringence and absorption) of materials used in 157-nm lithography systems: Calcium Fluoride (CaF2) for optical elements and fluorine doped fused silica for reticle substrates and pellicles. Particular emphasis is made on substantial absorption of materials in 157-nm wavelength region and related manufacturing aspects such as fluorinated resists and necessity of nitrogen purge. The existing (and projected) infrastructure, in terms of tool availability is explained. Recent developments in 157-nm technology, and its printing capabilities down to 45 nm are described.
This course presents an overview of the x-ray lithography (XRL) technology. The course provides an understanding of the status of the technology, its basis and limitations, and its applicability to several generations of IC's. After a brief review of the physical principles, the components of the manufacturing system are discussed in detail. Topics to be covered include: sources (with emphasis on synchrotrons), beamlines, masks, aligners, and resists. The discussion addresses manufacturing aspects, exposure control, and sources of overlay error. Particular emphasis is on the x-ray mask and the approach to optimal mask design. The existing (and projected) infrastructure, in terms of tools availability in the US and Japan is explained. The perceived limits and challenges of X-ray technology, recent developments, and its printing capabilities down to 25 nm are described.