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This paper presents a novel method of FIB (FIB: focused ion beam) sample preparation to accurately evaluate critical dimensions and profiles of ArF photo resist patterns without the use of a protective coating on the photo resist. In order to accomplish this, the FIB micro-sampling method [1] that is one of effective FIB milling and fabrication method was employed. First a Si cap is picked up from a silicon wafer and fixed to ArF photo resist patterns to protect against ion beam irradiation. Then, a micro-sample, a piece of Si-capped ArF photo resist, was extracted from the bulk ArF photo resist. In this procedure, this silicon cap always protects ArF photo resist patterns against ion beam irradiation. For the next step, the micro-sample is fixed to a needle stub of the FIB-STEM (STEM: scanning transmission electron microscopy) compatible rotation holder. This sample on the needle stub was rotated 180 degrees and milled from the side of Si substrate. Lastly, the sample is milled to the thickness of 2 µm. In this process, the ion beam is irradiating from the silicon substrate side to minimize the ion beam irradiation damages on the ArF photo resist patterns. EDX (EDX: Energy dispersive X-ray spectroscopy) analysis proved that no gallium ions were detected on the surface of the ArF photo resist patterns. The feasibility of high accelerating voltage observation of STEM to observe line edge roughness of a thick sample like 2 µm without shrinkage has been demonstrated.

As the feature size of semiconductor technology shrinks, cross-section metrology becomes more and more challenging. The generation of cross section metrology data is important for the introduction of new advanced integration schemes, rapid yield learning, and continuous process control for stable manufacturing. In this paper an automated way of TEM cross-section preparation by FIB is described to ensure fast cycle time for preparation and analysis. A dual column FIB/SEM system is used to prepare TEM samples from multiple locations of a 300 mm wafer batch. Subsequently, the TEM lamella is transferred to a grid using an ex-situ lift-out station. Two dedicated applications are shown, a Focus Exposure Matrix (FEM) on patterned photo resist and a process control case study on an etched poly-silicon transistor gate.