Rigaku Europe and Fraunhofer IISB partner on x-ray topography for substrate and epilayer characterization

Analytical and industrial instrumentation technology Rigaku Europe SE of Neu-Isenburg and Fraunhofer IISB (Institute for Integrated Systems and Device Technology) in Erlangen, Germany have formed a strategic partnership focusing on the characterization of semiconductor materials by x-ray topography. Rigaku has hence installed its latest-generation x-ray topography tool, the XRTmicron imaging system, at Fraunhofer IISB. “We are proud to join forces with the highly experienced team at IISB for semiconductor substrate and epilayer characterization,” comments Rigaku Europe’s president Dr Michael Hippler.

Enabling the investigation of crystallographic defects with high speed and high resolution on the full wafer scale, the XRTmicron system is suitable for bare wafers, wafers with epilayer structures, partially processed wafers, and bonded wafers. The amount and different types of dislocations, slip lines, dislocation networks, (small-angle) grain boundaries, inclusions, precipitates, pits, scratches, stress level etc can be imaged and quantified on the samples.

Two different x-ray sources – a 40kV/30mA copper source and a 50kV/24 mA molybdenum source in combination with the application of a large-angle goniometer – accommodate a wide range of diffraction conditions. The XRTmicron system can therefore be applied to different kinds of materials including semiconductors (e.g. Si, Ge, diamond, SiC, GaN, AlN, GaAs, InP, CdTe, CdZnTe), oxides (e.g. sapphire, ruby, garnets, vanadates, niobates, quartz) and halides (e.g. fluorides, bromides).

The XRTmicron system can be operated in transmission as well as in reflection mode in order to detect defects in the volume of the sample or to quantify defects close to the surface. Furthermore, it is equipped with a standard and a high-resolution XTOP CCD-camera, yielding spatial resolution of 5.4µm and 2.4µm per pixel, respectively, for a single image size of 18mm x 13.5mm. Full wafer mappings and detailed defect imaging of regions of interest are possible under different diffraction conditions for sample sizes of up to 300mm in diameter. A measurement of a full 150mm SiC wafer under the high-resolution mode, for example, takes only 1 hour.

Additionally, the XRTmicron system is equipped with a special slit-arrangement to perform cross-section topography measurements in high resolution. This gives detailed depth information through the whole thickness of the sample. For example, it is possible to investigate whether the glide plane formation in partly processed wafers starts on the front or back side of the wafer. Furthermore, the defect formation due to epilayer growth on top of a wafer can be quantified by this feature.

“The XRTmicron is the only tool available in Europe so far which fulfills the requirements of highest resolution for complete wafer mappings in shortest possible time scale to analyze single-crystalline materials,” says Dr Christian Reimann, group manager Silicon at Fraunhofer IISB. “It is a revolution for crystallographic defect investigations compared to classical synchrotron-based topography measurements.”

Fraunhofer IISB will act as a demonstration center for the XRTmicron system in Europe. “We already received numerous requests from the European semiconductor industry aiming to improve and better understand their product quality and yields,” says Rigaku Europe’s XRT product manager Uwe Preckwinkel. It is therefore planned to standardize the operation procedures for the different costumers due to their specific needs within the strategic collaboration between Rigaku and Fraunhofer IISB.

The XRTmicron system operated at Fraunhofer IISB is part of the ‘Research Fab Microelectronics Germany (FMD)’, which is funded by Germany’s Federal Ministry of Education and Research (BMBF). Within this Research Fab Microelectronics Germany, the Fraunhofer Group for Microelectronics and two Leibniz institutes (FBH and IHP) are bundling their expertise in order to reach and expand on a new quality in research, development and (pilot) manufacturing of semiconductor-based microsystems and nanosystems.

Tags: Metrology

Visit: www.iisb.fraunhofer.de

Visit: www.rigaku.com/en/products/xrm/xrtmicron