Technologies for 3D Heterogeneous Integration

3D-Integration is a promising technology towards higher interconnect densities and shorter wiring lengths between multiple chip stacks, thus achieving a very high performance level combined with low power consumption. This technology also offers the possibility to build up systems with high complexity just by combining devices of different technologies. For ultra thin silicon is the base of this integration technology, the fundamental processing steps will be described, as well as appropriate handling concepts. Three main concepts for 3D integration have been developed at IZM. The approach with the greatest flexibility called Inter Chip Via - Solid Liquid Interdiffusion (ICV-SLID) is introduced. This is a chip-to-wafer stacking technology which combines the advantages of the Inter Chip Via (ICV) process and the solid-liquid-interdiffusion technique (SLID) of copper and tin. The fully modular ICV-SLID concept allows the formation of multiple device stacks. A test chip was designed and the total process sequence of the ICV-SLID technology for the realization of a three-layer chip-to-wafer stack was demonstrated. The proposed wafer-level 3D integration concept has the potential for low cost fabrication of multi-layer high-performance 3D-SoCs and is well suited as a replacement for embedded technologies based on monolithic integration. To address yield issues a wafer-level chip-scale handling is presented as well, to select known-good dies and work on them with wafer-level process sequences before joining them to integrated stacks.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/16838

Cathodic Arc Evaporation of MCrALY Coatings

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phenoPET: A dedicated PET Scanner for Plant Research based on digital SiPMs

In the frame of the German Plant Phenotyping Project (DPPN) we developed a novel PET scanner. In contrary to a clinical or preclinical PET scanner the detector rings of the Plant System are oriented in a horizontal plane. The final system will be equipped with three rings covering a Field of View (FOV) of 18 cm diameter and 20 cm axial height. One detector ring is formed by 12 modules. Each module contains four 8×8 pixel digital SiPM devices DPC-3200-22-44 (Philips Digital Photon Counting) connected to a PCB and four scintillator matrices with 16×16 individual LYSO scintillators. Crystal size is 1.85×1.85×10 mm3. The matrices are composed with both reflective and transparent contact faces between the crystals in order to optimize crystal identification. A cooling system keeps the detectors below 5°C and limits the dark count rate. Data are already preprocessed by the Cyclone FPGA (Altera) in the module and transmitted from there at 50MiB/s to the base board. The base board collects the data from all modules and allows coincidence detection performed on a Kintex-7 FPGA (Xilinx). Finally the data link to the computer system for image reconstruction is realized via an USB 3.0 connection. Due to the fast photodetectors the system is dedicated to work with rather high activities. Preliminary measurements showed a coincidence peak of 250 ps FWHM between two detector elements and an energy resolution ΔE/E = 12%. This paper will present first results from a one ring system with a FOV of 18 cm diameter and 6.5 cm axial height

Low energy plasma processing (LEPP) for SiGe applications

AbstractMotivated by the need to grow fast high quality virtual substrates (VS) for strained Si / SiGe channels or for Ge/GaAs applications, Unaxis Semiconductors has developed low energy plasma processes (LEPP) which are running on a new LEPP 300 cluster tool. The system combines the utilisation of plasma for pre-epi clean and for epitaxial growth in a production system. It consists of two new processes both applicable for 300 mm wafers: the LEPC (low energy plasma cleaning) process, a dry low temperature (unkeyable???150 °C) process for wafer cleaning before epitaxial growth (pre-epi clean), and the LEPECVD (low energy plasma enhanced CVD), a deposition process which allows deposition rates in the range between 0.01 nm/s and several nm /s at 550°C

Triggering the phase evolution within (Al,Cr)2O3-based coatings by alloying and microstructural concepts

The final publication is available at Springer via https://doi.org/10.1007/s00501-016-0506-2.Bei der Synthese von Al2O3 und (Al,Cr)2O3 Schutzschichten mittels physikalischer Dampfphasenabscheidung treten neben der thermisch stabilen hexagonalen Struktur auch metastabile kubische Phasen auf. Durch die thermisch initiierte Umwandung können Rissnetzwerke entstehen und somit zu einer drastischen Reduktion der Schichtfunktionalität führen. Durch gezieltes Hinzulegieren von geringen Mengen an Eisen ist es möglich, die Gefüge-Anteile zugunsten der bevorzugten hexagonalen Phase zu verschieben. In detaillierten Transmissionselektronmikroskopie-Studien wurde dargelegt, dass dieser Entwicklung ein Nukleationsmechanismus an Cr- und Fe-reichen Teilchen (Droplets) zugrunde liegt, die durch selektives Aufschmelzen der Target-Oberfläche entstehen und während des Wachstumsprozesses in die Schicht eingebaut werden. Um den beobachteten Effekt besser zu verstehen und in weiterer Folge zur Steuerung der Synthese gewünschter Schichtstrukturen in Form von Target-Entwicklung zu nutzen, wurden weitreichende Elektronenmikroskopie-Studien am Target-Material und gezielt hergestellten intermetallischen Droplets durchgeführt.The synthesis of (Al,Cr)2O3 coatings by PVD frequently results in metastable cubic structures next to the thermodynamically stable and mechanically favourable hexagonal corundum phase. By alloying small amounts of Fe to powder-metallurgically produced Al0.7Cr0.3 targets – used to synthesise (Al,Cr)2O3 films by cathodic arc evaporation – a considerable increase of the hexagonal phase fraction is observed. Detailed transmission electron microscopy studies show that the growth of hexagonal crystallites of a solid solution (Al,Cr,Fe)2O3 can be triggered by small Cr- and Fe-enriched spherical particles, so-called droplets. In contrast, larger spherical or flat-shaped Al-rich droplets induce re-nucleation of undesired cubic film growth. Extending these studies to additional (Al,Cr)2O3 coating systems revealed similar mechanisms, albeit by far less frequent than in the case of Fe-alloyed films. Modifications of the chemical composition of the target by small amounts of dopants may reduce droplet generation and contribute to controlled coating nucleation. Therefore, the cathode surface used is compared with particles, intentionally selected from the plasma stream

Silicon etch with chromium ions generated by a filtered or non-filtered cathodic arc discharge

The pre-treatment of substrate surfaces prior to deposition is important for the adhesion of physical vapour deposition coatings. This work investigates Si surfaces after the bombardment by energetic Cr ions which are created in cathodic arc discharges. The effect of the pre-treatment is analysed by X-ray diffraction, Rutherford backscattering spectroscopy, scanning electron microscopy and in-depth X-ray photoemission spectroscopy and compared for Cr vapour produced from a filtered and non-filtered cathodic arc discharge. Cr coverage as a function of ion energy was also predicted by TRIDYN Monte Carlo calculations. Discrepancies between measured and simulated values in the transition regime between layer growth and surface removal can be explained by the chemical reactions between Cr ions and the Si substrate or between the substrate surface and the residual gases. Simulations help to find optimum and more stable parameters for specific film and substrate combinations faster than trial-and-error procedure.ISSN:1468-6996ISSN:1878-551