Rudolph Technologies Inc. has acquired patented illumination, autofocus and image acquisition technology for microelectronics inspection from Stella Alliance LLC of Massachusetts. Terms of the transaction were not disclosed. The technology enables identification of residue-related defects not visible with current techniques, according to Rudolph. These defects can have a significant impact on the interconnect quality, such as incomplete etch of bond or bump pads, faint copper bridging and stringers at the bottom of vias, and high-aspect-ratio trenches in fan-out wafer level packaging, wafer-level chip-scale packaging and embedded die applications. In addition, the technology provides the resolution needed to inspect highly warped rectangular panels larger than 500 mm. With this acquisition, Rudolph expects to add a next-generation, high-resolution inspection system to its product offerings in the second quarter of 2016. Stella Alliance technology is able to handle large rectangular substrates, which Rudolph said will help it serve growing segments of microelectronic device manufacturing. "As interconnect technology becomes increasingly important in back-end 3D and 2.5D applications, we anticipate this inspection technique to be a key component for our customers' process control strategies," said Mike Goodrich, vice president and general manager of Rudolph's Inspection Business Unit. Rudolph Technologies develops products for defect inspection, lithography, process control metrology, and data analysis for semiconductor and advanced packaging device manufacturers worldwide.