SBIR-STTR Award

This Small Business Innovation Research (SBIR) Phase I project is for the construction of an ultra-high-resolution, high-precision phase-shift measurement tool suitable for metrology of advanced phase-shifting photomasks. A number of semiconductor manufacturers now expect to progress from the 90 nm through the 45 nm nodes using an exposure wavelength of 193 nm. Advanced photolithographic techniques are necessary to print these sub-wavelength features. Phase-shift photomasks, i.e., those in which the optical thickness, as well as the opacity is controlled, are a key reticle enhancement technology. Fast and accurate metrology of critical-layer phase-shift masks is becoming necessary, both for process control and repair validation, but the enabling tools do not yet exist. The goal of this SBIR Phase I project is to develop a new, solid-state, high-repetition-rate actinic 193.4 nm laser with high spatial coherence and stability. This illumination source will be integrated into an existing prototype microscope tool to demonstrate high-speed, highly precise phase metrology suitable for use in the 90, 65, and 45 nm node device generations. The project involves the design and construction of a novel optical-parametric-oscillator and a number of associated nonlinear frequency conversion elements. The commercial application of this project will be in the semiconductor lithography industry. The semiconductor industry roadmap for the 90 nm mode and beyond requires measurements of photomask optical path difference with sub-0.4 degrees precision. This metrology must be performed at resolution scales consistent with feature sizes of the respective technology nodes, and for both isolated and densely packed structures. No commercial devices yet exist which satisfy these demands. The high-repetition-rate actinic laser source described in this proposal is a key enabling technology for a new high-precision metrology tool. Further, as a high-power stand-alone source, the ultra-violet (UV) laser will meet the associated optical demands of advanced photolithography, including imaging, bulk material and coating analyses, and damage tests

This Small Business Innovation Research (SBIR) Phase II project aims to design and construct an ultra-high-resolution, high-precision phase-shift integrated measurement system suitable for metrology of advanced phase-shifting photomasks. A number of semiconductor manufacturers now expect to progress from the 90 nm through the 45 nm nodes using an exposure wavelength of 193 nm. Advanced photolithographic techniques are necessary to print these sub-wavelength features. Phase-shifting photomasks, i.e. those in which the optical thickness, as well as the opacity is controlled, are a key reticle enhancement technology. Fast and accurate metrology of critical-layer phase-shift masks is becoming necessary both for process control and repair validation, but the enabling tools do not yet exist. The goal of this Phase II program is to integrate the actinic high-repetition rate laser built in Phase I into an interferometric laser microscope involving the design, construction, and integration of a stable phase-shifting interferometer and laser microscope, and the incorporation and optimization of phase-shifting interferometry signal processing algorithms. The integrated optical system will enable phase metrology on advanced photomasks, with the measurement precision and spatial resolution required by the International Technology Roadmap for Semiconductors (ITRS), mask makers and mask users. Commercially, the primary beneficiary of the Phase II photomask phase metrology system is the semiconductor optical lithography industry. The ITRS 'roadmap' for the 90-nm node and beyond requires measurements of photomask optical path difference with sub-0.4 degree precision. This metrology must be performed at spatial resolution scales consistent with feature sizes of the respective technology nodes, and for both isolated and densely-packed structures. No commercial metrology tools yet exist which satisfy these demands. The Phase II high-precision metrology system will enable manufactures to characterize, predict, and control mask-loading effects and other repair and process control issues essential to the reliable fabrication of phaseshifting masks. It is also likely that the integrated phase metrology system will find utility in the area of nano-MEMS testing and other nano-scale interferometry.