Research Network for Advanced Lithography

The primary task of this Network is to identify, evaluate, characterize, and advance promising (potentially production worthy) approaches to lithography for the generations requiring feature sizes at or below 100nm. The research aims to work on the most difficult technological challenges facing every candidate lithography approach and investigate various approaches to overcome these challenges.

A major focus of the Network is to research maskless lithography. Whereas the technical challenges are huge, the potential payoff is enormous, compelling a broad, open-minded effort. Radical new approaches to lithography, offer significant cost savings or throughput increase because of simplicity and parallelism. Projects are underway on scanning proximal probes, parallel arrays of e-beams, and arrays of x-ray spots focused by zone plates. Several other approaches are at an earlier stage of investigation.

The Research Network

Lithography is recognized as the key technology pacing the evolution of microelectronics and the introduction of nanoelectronics. Projection optical lithography has provided many generations of improvements in feature size, overlay accuracy, throughput, and will continue to do so for several more generations. Whereas there is no consensus whether optical lithography (as we know it) will reach 150, 130, or 100nm, there is a reasonable agreement that extensions of existing technology are not capable of meeting the lithography requirements of the 100nm generation and beyond, needed beginning in the middle of the next decade. The Network for Advanced Lithography thus brings together 4 University teams to research possible approaches to lithography at 100nm and beyond.

The primary task of this Network is to identify, evaluate, characterize, and advance promising (potentially production worthy) approaches to lithography for the generations requiring feature sizes at or below 100nm. The research aims to work on the most difficult technological challenges facing every candidate lithography approach and investigate various approaches to overcome these challenges. For example in EUV lithography the Network research is concerned with ultimate resolution limits inherent in the technology, with the very challenging metrology requirements in optic characterization, and with the problem of verification of defect levels in EUV masks. In E-beam lithography, the concerns are fundamental limits in overlay capability, and throughput limits, both stemming directly from the use of charged particles. There is no significant effort within the Network on x-ray lithography, owing to the large industrial and university programs already in place on that technology.

A major focus of the Network is to research maskless lithography. Whereas the technical challenges are huge, the potential payoff is enormous, compelling a broad, open-minded effort. Radical new approaches to lithography, offer significant cost savings or throughput increase because of simplicity and parallelism. Projects are underway on scanning proximal probes, parallel arrays of e-beams, and arrays of x-ray spots focused by zone plates. Several other approaches are at an earlier stage of investigation.

The success of any of the future lithography technologies depends on the supporting technology infrastructure. Thus the Network also includes research which deals with key elements of this infrastructure. The first is metrology. One goal of this effort is to determine the capabilities of wavefront metrologies needed for the manufacture of precise optical surfaces. Another addresses overlay. The research has the goal of developing and characterizing novel approaches to the increasingly difficult job of aligning lithographic layers. Both a fundamental, global, alignment method (IBBI) and various approaches to improve local alignment are included. The second major infrastructure area is resist technology. The resist work has the very broad goals of inventing and synthesizing new resist systems, modeling the exposure, processing, and development of the resists, and exploring radically different pattern transfer techniques such as embossing and image-catalyzed growth of polymers. A third important infrastructure area deals with the tools needed to design and analyze the advanced technologies under investigation for candidate lithography approaches. Defined broadly as research on CAD and simulation tools, it deals with the computational infrastructure needed for advanced lithography. The first of two main thrusts has the goal of finding efficient codes for pre-compensating pattern data in order that the final wafer pattern is least subject to the bandwidth and distortion limitations of the writing instrument. The second thrust is concerned with the continued evolution of electromagnetic simulation codes so that the design of state-of-the art tools and structures can respond to the limits posed by the very small geometries of the sub-100nm era.