Advanced Packaging: Ball Grid Array
Ball grid array (BGA) is a surface-mount packaging technology consisting of an array of solder balls on the underside of a chip package. BGA has been developed in response to the trend in the semiconductor industry towards the miniaturisation of ICs, and in pursuit of higher integration, higher density, and improved functionality. TESCAN systems offer a wide range of possibilities for inspection and failure analysis of BGA packaging. The TESCAN BSE detector provides high contrast which makes intermetallic compounds and under-bump metallurgy layers clearly visible. TESCAN Plasma FIB-SEM systems (FERA3, XEIA3) allow solder balls, which can have diameters of up to hundreds of microns, to be effortlessly and seamlessly cross-sectioned in an unrivalled short time frame. Fast 3D microanalysis (3D EDX, 3D EBSD) of whole solder balls is possible with the ultra-high sputtering rates that only the Xe plasma FIB can offer.
Circuit edit (CE) is a common technique used in the design-debug phase of integrated circuits. Most CE activities are performed by means of FIB systems equipped with a Gas Injection System (GIS). Such systems allow site-specific and precise material etching as well as the deposition of conductive contacts or insulation. Any TESCAN FIB-SEM system can be equipped with a GIS for enhanced and optimise a wide range of FIB applications including circuit edit. Two options for GIS configuration are available: a 5-nozzle motorised GIS or multiple MonoGIS units. In either option the following precursors are available: Tungsten for metal deposition, SiOx for insulator deposition, H2O for enhanced etching Cu and XeF2 for selective etching of Si, SiOx, and Si3N4. TESCAN LYRA and GAIA FIB-SEM systems are equipped with the DrawBeam lithography module, dedicated, user-friendly and effective software for precise etching, deposition and end-point detection required for advanced circuit editing applications.
The development of displays has progressed rapidly in recent years, and this has resulted in high quality displays which deliver sharp and bright images, wide viewing angles, vivid colours, all in a touch-sensitive layer. TESCAN offers a series of instruments well-suited for the display industry. Displays are delicate structures which can be easily damaged by an electron beam. The TESCAN MAIA3 FEG-SEM provides superb resolution even at low beam energies, ideal for damage-free imaging and resolving the beam-sensitive small structures in displays without the need of using protective coatings. GAIA3 is ideally suited to perform small area cross-sectioning of a couple of tens of microns wide in TFT. The XEIA3 system – a Xe plasma ion source FIB – is the solution for preparing large-scale cross-sections in TFT displays, and for the characterisation of defects.
Rocking Stage for Curtaining-Free Polishing
For successful failure analysis, the semiconductor industry relies on high quality surfaces on cross-sections and lamellae. The surface of the cross-sections or that of lamellae need to be smooth and artefact-free, otherwise, the task of finding or identifying possible failures is very difficult as they can easily hide among surface defects. The TESCAN Rocking Stage, a stage which allows multi-directional milling by tilting the sample during FIB milling. Such a technique has proven not only to be effective in eliminating curtaining but also in optimising cross-sectioning tasks and lamellae final polishing. Furthermore, the Rocking Stage allows a simultaneous SEM imaging during FIB milling, hence, the quality of the surface can be monitored at all times without the need to interrupt the milling process.