The technology roadmaps for the semiconductor industry aim at constantly shrinking device dimensions to achieve higher level of performance through miniaturization and integration. Furthermore, device geometries become increasingly complex, where 3D scaling is anticipated to introduce new functionalities and to make optimum use of the available space. The trends are such that conventional technologies currently used for production and control are reaching their physical limits. In order to sustain the development sketched above, technological breakthroughs and new disruptive technological platforms are required.

Proposed research

Optical metamaterials emerged in the last years as a disruptive technology platform for the development of innovative optical components and systems. These structures, which offer full simultaneous polarization and phase control, allow not only the replacement of existing bulk optical components with ultra-thin surfaces, but they can allow also the realization of novel components which do not actually have a bulk conventional counterpart.

The main objective of this project is to investigate and develop an optical system, based on innovative metamaterial lenses (meta-lenses). This system will be used as super-resolution optical sensor of a new generation of metrology and inspection instruments (meta-instruments). Such instruments will be capable to provide the level of resolution required by the current trends of the semiconductor industry, but without the typical problems of current systems, based on Scanning Electron Microscopes (SEMs), or Atomic Force Microscopes (AFMs). SEMs have the well-known disadvantages of large measurement times and potential radiation damages of the photo-resist layer. The main issues for AFMs are the frequent damages of the cantilever tips during the scanning, which require an expensive maintenance, but also the possible damages of the surface under inspection, due to undesired contacts between the tip and the surface. The overall instrument concept is the subject of a considerable research and development effort at TNO, in the framework of a new research program named “ERP 3D Nanomanufacturing Instruments”. TNO is also the sponsor of several other related PhD projects at TU/e and TUD supporting this research activity, addressing all the aspects of such an instrument in a multi-disciplinary approach. The PhD candidate of this project will work in thigh cooperation with the other colleagues and share the same ultimate, unifying goal. The novel optical sensor will be a key part of the instrument, therefore requiring an appropriate knowledge of the complete system concept. A schematic representation of the systems is shown in fig. 1. Through the cooperation with the TNO scientists involved in the development of the instrument and the other PhD students addressing all the relevant research aspects, it will be possible to conceive the optical sensor in such a way to guarantee a full operational integration.

Different concepts will be considered (e.g. all dielectric super oscillatory lenses, hyper-lenses based on negative refractive index metamaterials) and assessed with respect to the requirements of the metrology system, manufacturability and material properties.

The ultimate goal, in terms of wavelength of operation, is the one used in Deep Ultra Violet (DUV) lithography (ℵ= 193nm). In terms of resolution, the goal of the project is to achieve direct imaging of 3D structures on the wafer, with feature size in the range from 40nm down to better than 10nm. Nano manufacturing technologies and material properties are also very important aspects considering the extremely small wavelengths and a particular attention will be devoted at establishing co-operations with all the relevant disciplines.

Experts and stakeholders

TNO: The activity on metamaterials at TNO are executed in the Optics department and are coordinated by Prof. dr. G. Gerini (PhD first promotor). TNO will also support the PhD with its expertise on advanced manufacturing technologies and nano-opto-mechatronics aspects, through the participation of Dr. ir. H. Sadeghian.

ASML: ASML will provide experimental support, in terms of know-how on wafer-metrology platforms as is available in the SMC-Research department. In the PhD project, ASML will be directly involved through the participation of Prof. dr. W. Coene.

TU/e: The following TU/e research groups are involved in this project: Electromagnetics (Prof. dr. G. Gerini, Dr. V. Lancellotti), Control Systems (Prof. dr. W. Coene). The PhD first promoter is Prof. dr. G. Gerini.

Applicants can submit their application here.