October 20, 2006, Rochester, NY--Navitar has developed a deep-ultraviolet (DUV) zoom lens that is designed to work with microscope objectives; its 4X zoom range is well-suited for inspection applications.
Over the years, feature sizes on semiconductor wafers, data-storage devices, and microelectronic components have continued to shrink well below the wavelength of visible light. Navitar's response to this increasing need to extend resolution limits for optical inspection is the company's NanoVue 248 nm zoom lens. The DUV operating wavelength effectively doubles the resolution ability of conventional visible-light microscopes.
The lens is designed to work with 248 nm DUV infinity-corrected microscope objectives to enable optical inspection to under 0.1 micron; the lens has a zoom range of 0.75X to 3X. When combined with a 100X objective corrected at a 200 mm tube length, a zoom range of 75X to 300X is possible. A field of view of 0.14 to 0.37 mm can be achieved when using a 100X infinity-corrected DUV objective with a 2/3" format sensor. A motorized version is available to speed the observation process and automation of critical image data acquisition.
The small and flexible optical footprint of the lens enables a broad range of inspection and defect-review tasks, including DUV reticle and photomask inspection, thin-film measurement, wafer inspection, CD (critical dimension) metrology, failure analysis, and process control. Using the zoom lens coupled with a single objective, an instrument operator can zoom in on particular details of interest and achieve the exact field of view required while still resolving the important details.