Dual platform stepper/scanner-based overlay evaluation method

In this work we address the capability of an alternative overlay evaluation method for the entire BEOL-Process of IHP’s standard 0.25 and 0.13 μm SiGe:C BiCMOS technology. A dual lithography platform NIKON® NSR 210D/207D scanners and NIKON® NSR SF-150 i-Line stepper layer crossing and wafer bow related overlay issues will be discussed. Stack alignment marks, which serves the exposure alignment and overlay determination were introduced. A mismatch for overlay (x/y) |mean| + 3σ values below 8 nm between the KLA® ARCHER 100 overlay and both lithography tools could be demonstrated.