Bruker Corp has introduced its LumiMap electroluminescence system for high-brightness light-emitting diode (HB-LED) epi wafer process metrology. Joining a suite of other Bruker HB-LED epi metrology tools, LumiMap incorporates many of the advanced features of Bruker’s flagship metrology products. Proprietary, patent-pending features of the new system include the durable conducting probe, a unique wafer edge contact solution, and advanced I-V curve modeling for accurate and repeatable forward voltage value measurement. These features enable LumiMap to deliver the most accurate and repeatable forward and reverse IV characteristics, spectral intensity, wavelength and spectral width measurements on 2- to 6-inch epi wafers, with a wide range of current settings, says the firm.
“LumiMap provides more accurate and reliable electrical and optical epi wafer measurements than the traditional indium dot method,” said Dr. Ryan Lee, executive VP and CTO of Foshan Nationstar Optoelectronics Co Ltd. “A reliable electro-luminescence quality check immediately after MOCVD will help us further improve epi wafer yield and reduce costs.”
LumiMap is an alternative to conventional, multistep, operator-dependent indium dot methods of epitaxial wafer characterization. The system features rapid, non-destructive, no post measurement chemical cleaning, software-controlled measurement locations, and repeatable optical and electrical measurement capabilities through forming a temporary LED device on an epi wafer. The results obtained by LumiMap are well correlated with those on the final HB-LED device, providing an early warning of process shifts, which in turn reduces the risk of expensive scrap events and improves yields. Simple wafer exchange and intuitive software provides an easy to use interface for production quality control, as well as epi process development. The long measurement lifetime of the proprietary conducting probe meets the strictest industry cost of ownership requirements.
“Bruker is pleased to bring a new technology solution to HB-LED manufacturing, rounding out our other HB-LED metrology technologies in 3D optical microscopy, atomic force microscopy and XRD/XRF for PSS wafers and epi wafer multi-quantum layer characterization,” said Dr. Xiaomei Li, vice president of Segment Marketing of the Bruker Nano Surfaces division. “LumiMap ideally serves stringent HB-LED manufacturing cost reduction goals at a time when the industry is poised for unprecedented growth.”
“LumiMap electroluminescence technology fills the current lack of fast, non-destructive, reliable and repeatable optical and electrical measurement solutions to improve epi wafer yield and LED device quality at the epi wafer stage,” added Robert M. Loiterman, executive vice president and general manager of Bruker’s Stylus and Optical Metrology Business. “With LumiMap, the HB-LED industry can now get accurate electrical and optical feedback in minutes rather than days, reducing scrap events and operating costs.”
