Presentation Information
[23a-P07-19]3D Thin-Film Metrology using Lateral High Aspect Ratio Test Structures with Advanced Optical Techniques
〇Feng Gao1, Mikko Utriainen1, Jussi Kinnunen1, Wataru Momose2 (1.Chipmetrics Ltd., 2.ALD Japan Inc.)
Keywords:
3D,LHAR,Semiconductor
3D vertical scaling is one of the leading megatrends in nanoelectronics. It has made both conformal ultra-thin films and high-aspect ratio (HAR) features as prerequisites in today’s semiconductor industry. The PillarHall LHAR method eliminates the need for destructive cross-sectioning of samples, as the film penetration depth (PD) profile can be measured directly from the surface. In this study, we focus on measuring the PD profile and thickness of ultra-thin ALD Al2O3 films on the PillarHall LHAR structures. We employed both optical and electron microscopy techniques alongside line-scan reflectometry and imaging ellipsometry, discussing the advantages and limitations of each method. Additionally, we explored the uniformity of wafer-level conformality, a critical aspect for tool qualification and process uniformity in manufacturing. By placing and bonding the PillarHall test chips on a silicon pocket wafer, the conformality measurements in a wafer level becomes easily accessible. The novel Front-End of Line (FEOL) compatible integration of the PillarHall test chip with 300 mm pocket wafers showcases a promising test vehicle for 3D thin film characterization. The combination of the PillarHall metrology wafers and the imaging ellipsometer forms a promising new toolset for monitoring thin film conformality for the advanced semiconductor device manufacturing.