Markus Mengel

The impact of projection lens polarization properties on lithographic process at hyper-NA

The continuous implementation of novel technological advances in optical lithography is pushing the technology to ever smaller feature sizes. For instance, it is now well recognized that the 45nm node will be executed using state-of-the-art ArF (193nm) hyper-NA immersion-lithography. Nevertheless, a substantial effort will be necessary to make imaging enhancement techniques like hyper-NA immersion technology, polarized illumination or sophisticated illumination modes routinely available for production environments. In order to support these trends, more stringent demands need to be placed on the lithographic optics. Although this holds for both the illumination unit and the projection lens, this paper will focus on the latter module. Today, projection lens aberrations are well controlled and their lithographic impact is understood. With the advent of imaging enhancement techniques such as hyper-NA immersion lithography and the implementation of polarized illumination, a clear description and control of the state of polarization throughout the complete optical system is required. Before polarization was used to enhance imaging, the imaging properties at each field position of the lens could be fully characterized by 2 pupil maps: a phase map and a transmission map. For polarized imaging, these two maps are replaced by a 2x2 complex Jones matrix for each point in the pupil. Although such a pupil of Jones matrices (short: Jones pupil) allows for a full and accurate description of the physical imaging, it seems to lack transparency towards direct visualization and lithographic imaging relevance. In this paper we will present a comprehensive method to decompose the Jones pupils into quantities that represent a clear physical interpretation and we will study the relevance of these quantities for the imaging properties of lithography lenses.

Update on the SEMATECH 0.5 NA Extreme-Ultraviolet Lithography (EUVL) Microfield Exposure Tool (MET)

In support of the Extreme Ultraviolet Lithography (EUVL) roadmap, a SEMATECH/CNSE joint program is underway to produce multiple EUVL (wavelength of 13.5 nm) R&D photolithography tools. The 0.5 NA projection optic magnification (5X), track length and mechanical interfaces match the currently installed 0.3 NA micro-field exposure tools (MET) projection optic [1] [2] [3]. Therefore, significant changes to the current tool platforms and other adjacent modules are not necessary. However, many of the existing systems do need upgrades to achieve the anticipated smaller exposure feature sizes [4]. To date we have made considerable progress in the production of the first of the two-mirror 0.5 NA projection optics for EUVL [5]. With a measured transmitted wave front error of less than 1 nm root mean square (RMS) over its 30 μm × 200 μm image field, lithography modeling shows that a predicted resolution of ≤12 nm and an ultimate resolution of 8 nm (with extreme dipole illumination) will be possible. This paper will present an update from the 0.5 NA EUVL program. We will detail the more significant activities that are being undertaken to upgrade the MET and discuss expected performance.

Controllable bumps and holes fabrication on the surface of fused silica by processing bulk material with ultrashort laser pulses

Processing of bulk transparent dielectrics with ultrashort laser pulses is widely used for direct writing of waveguides, gratings, couplers and other photonics devices inside the volume of material [1]. This technique is based on the modification of bulk glass material or voids formation, which depends on processing conditions.