The MetaPULSE® system has long been established as the market leader for metals metrology in the semiconductor industry. The success of Picosecond Ultrasonic Laser Sonar (PULSE) technology has been built on its unique ability to provide non-contact, non-destructive, on-product metrology for FEOL, BEOL, and C4 applications. In the past year, Rudolph’s Metrology Business Unit has been working with major manufacturers and process tool providers from the flat panel display (FPD) and LED markets to offer PULSE -based solutions suited to meet the specific needs of these very different markets.

Today, most large FPDs use an active matrix technology in the manufacturing process. Active matrix technology employs the use of thin-film transistors (TFT) of either amorphous or polycrystalline silicon applied to the rear FPD glass. The TFT formation is very similar to that used in semiconductor manufacturing. The process includes PECVD for deposition of a-Si and the gate dielectric insulation layer, deposition of gate metals, and sputtered metal data and scan lines. A typical process includes the deposition of a series of gate metals such as Cr, Ta, Al, MoTa as well as deposition of Ti and/or Al source and data lines. The TFTs cover a small fraction of the area of each pixel in the display. The remaining area of the silicon film is etched away to allow light to pass through. Applications studies for traditional and advanced FPD manufacturing processes have proven that PULSE is a unique technology that can provide non-contact, non-destructive measurements of these metals individually or in a stack with gauge capability. Process control of these layers is directly related to panel performance and yield. Rudolph’s current activity is centered on a repackaging of the PULSE measurement head with large substrate handling to accommodate the wide range of FPD sizes being manufactured. A challenge in itself, but solutions are being engineered. The goal is to provide this critical metal metrology for all generations of FPD manufacturing. Initial systems are targeted to ship in Q2 2012 for R&D lines.