Kuo, Bo-ChenBo-ChenKuoYang, Fu-ShengFu-ShengYangDas, SurajitSurajitDasLin, Yuan-CiYuan-CiLinChou, Wei-XiangWei-XiangChouHuang, Ting-HuiTing-HuiHuangNajera, LuisLuisNajeraLIANG-CHIA CHEN2026-01-082026-01-082025-08-0897815106904240277786Xhttps://www.scopus.com/record/display.uri?eid=2-s2.0-105022978038&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/735142Advancements in 3D integrated circuits (3DIC) and Chip-on-Wafer-on-Substrate (CoWoS) packaging demand precise metrology of high aspect ratio (HAR) microstructures, challenging conventional inline measurement techniques. Traditional back focal plane (BFP) scatterometry offers high sensitivity to lateral critical dimensions (CDs) but lacks depth resolution. To address this, we present a hybrid visible-to-shortwave infrared (SWIR) spectroscopic scatterometry system that combines BFP scatterometry with spectroscopic reflectometry. A low numerical aperture (NA) normal incidence configuration and angle-scanning module are employed to enhance depth sensitivity and lateral CD accuracy, respectively. The SWIR range improves bottom CD and sidewall angle assessment due to deeper penetration. Global sensitivity analysis (GSA) guides system optimization, and BFP imaging supports lateral CD extraction. Experimental validation demonstrates CD measurement errors under 1.95%, confirming the system's precision for HAR metrology.falseBack Focal PlaneGlobal Sensitivity AnalysisHigh Aspect Ratio StructureHybrid MetrologyScatterometryconference paper10.1117/12.30665102-s2.0-105022978038