Evaluation of the impact of solder die attach versus epoxy die attach in a state of the art power package

Subject of this paper is the thermal investigation of epoxy (EDA) and solder (SDA) die attaches by a comparison of an ASIC with multiple heat sources in different package assemblies. Static and transient thermal measurements and simulations were performed to investigate the thermal behavior of two samples in a state of the art QFP power package differing only in the die attach material (EDA and SDA).Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

Model Reduction for Power Electronics Systems with Multiple Heat Sources

Fast transient analysis of electronic systems thermal behavior is a vital tool for the examination of integrated circuits during the development. In an operational as well as in failure mode, this kind of analysis is needed to verify that operation conditions will remain safe for complex mixed signal electronic systems. Many of the questions, which have to be evaluated, are coming up in the last stages of the development, when the time to take a decision has to be short, and the designers need fast and accurate answers. A formal model reduction approach allows us to take a high dimensional finite element model and generate its low-dimensional approximation formally. As such, it is an ideal candidate for the goal above. Several research groups have already documented its successful application to a thermal problem with a single heat source. In the paper, we present the application of model reduction to a thermal problem with many independent heat sources. We demonstrate that the block Arnoldi process allows us to automatically build accurate compact dynamic thermal models while preserving independent heat sources in the reduced model. We discuss computational time necessary to perform model reduction. We show that a simple approach based on local error indicators allows us to choose automatically the dimension of the reduced system. We present the complete flow of using the method in engineering environment : Modeling in ANSYS the original problem, Model reduction with MOR for ANSYS, Evaluation of results using Mathematica

High-K metal gate stacks with ultra-thin interfacial layers formed by low temperature microwave-based plasma oxidation

Ultra-thin interfacial silicon oxide layers are grown by microwave-based plasma oxidation at temperatures below 200 °C. The influence of plasma gas composition and plasma pulsing on layer properties is tested. The oxides are compared to standard thermally grown oxide and wet chemical oxide. Layer properties are evaluated by x-ray photo electron spectroscopy and are electrically characterized by means of TiN/HfO2/SiO2 high-k metal gate stacks

Low-temperature microwave-based plasma oxidation of Ge and oxidation of silicon followed by plasma nitridation

In the semiconductor industry Germanium is expected as the promising channel material for future high-mobility CMOS transistors because of its highest hole mobility among common elemental and compound semiconductors, and an electron mobility that is two times larger than that of Si. This article shows that oxides can be grown and/or in a subsequent process step nitridized for planar Ge and Si devices at very low temperatures (T < 460°C). The stable oxide growth on Germanium through plasma processing is studied as a function of relevant processing parameters like time, gaseous ambient etc. For Silicon the bonding structure of pure and nitridized low-temperature grown SiO2 is analyzed, followed by an electrical characterization of 0.8 to 1.2 nm interfacial layers on Si

Model Reduction for Power Electronics Systems with Multiple Heat Sources

Abstract — The paper demonstrates the model order reduction procedures applied to semiconductor devices with multiple heat sources. The approach is demonstrated for a device with nine heat sources where some of them are permanently active and other work under switching conditions. For the order reduction the software package MOR for ANSYS is used, which is based on the Krylov subspace method via the Arnoldi algorithm. I

Reliability improvements of TiN/Al2O3/TiN for linear high voltage metal-insulator-metal capacitors using an optimized thermal treatment

Metal–insulator–metal (MIM) capacitors with TiN and high thickness of Al2O3 above 50 nm were fabricated to address high voltage (>30 V) and linear capacitor applications. Atomic layer deposition is used to deposit both TiN and Al2O3 to guarantee a good composition and thickness control. The impact of the deposition process and post-treatment condition on the MIM capacitor's breakdown voltage is studied and correlated with time of flight-secondary ion mass spectrometry (ToF-SIMS). Higher deposition temperature and thermal treatment of TiN and Al2O3 after deposition increase breakdown voltage and improve uniformity. ToF-SIMS demonstrates that Al2O3 higher deposition temperature or rapid thermal processing annealing reduce the diffusion of TiN in Al2O3 leading to thinner TiN/Al2O3 interface layers that influence breakdown voltage and uniformity

Electrocaloric temperature change in ferroelectric Si-doped hafnium oxide (HfO2) thin films: Presentation held at 37th Spring Meeting of the European Materials Research Society, E-MRS 2019, 27-31 May 2019, Nizza

Ferroelectric HfO2-based thin films receive extensive research interest due to their large spontaneous polarization, scalability, and CMOS compatible manufacturing. As in ferroelectrics, the remnant polarization exhibits a temperature dependence, one can observe a strong pyroelectric response in such films. Recently, the pyroelectric effect of doped HfO2 films has been observed [1]. The electrocaloric effect is closely related to it, as describing a temperature change of the material due to the application of an electric field. First published results indicate rather large electrocaloric coefficients, making doped HfO2 a promising candidate for on-chip solid-state cooling [2]. In this work, a specialized test structure is used to directly assess the strength of the electrocaloric effect in a 20 nm Si-doped HfO2 nano-laminate. A thin-film temperature sensor is formed on the metal-ferroelectric-metal structure, enabling excitation frequencies of up to 60 kHz. Measurement with respect to an electric bias field provides insight into the nature of thermal-electric energy conversion in HfO2 thin films. Additionally, bias dependent pyroelectric measurements are employed to assess the role of defect dipoles, which may have important implications for electrocaloric applications