Analysis of the plastic deformation in aluminium metallizations of Al2O3 - based DAB substrates

DAB are a new kind of substrates in which the copper layer was replaced by an aluminum layer. In [1] a increase of the roughness of these aluminum layer was observed during thermal cycling tests. A similar effect was observed during power cycling tests in [2, 3]. This paper will discuss this effect with experimental results and Finite Element (FEM) simulations

High resolution failure analysis of silver-sintered contact interfaces for power electronics

In this paper, results of failure analysis on silver-sintered chip backside and substrate contacts for power electronics modules using non-destructive Scanning Acoustic Microscopy (SAM), high resolution Scanning and Transmission Electron Microscopy (SEM, TEM) as well as Time-of-Flight Secondary Ion Mass Spectrometry (ToF SIMS) are presented. Specific attention is given to the microstructure of both contact interfaces, chip metallization to silver-sinter layer and silver-sinter layer to substrate metallization. In general, silver-sinter joints show an excellent bonding quality for most of the investigated chip and substrate metallization systems. Critical failure sites identified in this study are the formation of silver sulfide (Ag2S) at Ag-metallization/ Ag-sinter interfaces and contaminations on top of chip and substrate metallizations. Beside the interface issues, micro cracks and void like defects were detected within some specific chip and substrate metallization systems, respectively. Such defects can affect the strength properties and form a risk for both bonding quality and reliability

Failure mechanisms and mechanical characterization of reactive bonded interfaces

This study presents results of microstructure diagnostics and mechanical strength investigations for reactive bonded components. For this purpose silicon (Si) test specimen were bonded by using commercially available 40 µm thick nickel/aluminum (Ni/Al) NanoFoils{copyright} with a 10 µm thick tin (Sn) solder layer on both sides. Scanning electron (SEM) and high resolution transmission electron microscopy (HRTEM) in combination with energy dispersive X-ray spectroscopy (EDXS) at the bond interface showed the formation of silver-copper-tin (Ag-Cu-Sn) and tin-silver (Sn-Ag) intermetallics within the Sn solder matrix. The hardness and modulus of the solder layer were characterized by Berkovich nanoindentation testing. Results from strength investigations using tensile and micro chevron testing revealed a strong bonding strength of the interface. SEM analyses of the fracture surfaces showed both, cohesive failure through the solder layer and adhesive failure between the silicon substrate and the gold-chrome coating layer

Laparoscopic radical nephrectomy with inferior vena cava thrombectomy: highlight of key surgical steps

ABSTRACT Objective: Vascular involvement in the form of renal vein (RV) or inferior vena cava (IVC) thrombus can be seen in 4-10% of patients presented with RCC. In patients without presence of metastasis, surgical treatment in the form of radical nephrectomy remains the treatment of choice with 5-year survival rates of 45-70%. Open surgery is still the first treatment option of choice at the moment for RCC patients with IVC thrombus. Materials and Methods: In our study, we are reporting a case of patient with RCC and level I IVC thrombus treated with laparoscopy. Our patient is a 72 years old man with underlying co-morbidity of hypertension and chronic kidney disease (CKD) presented with right-sided RCC. The CT scan done showed a large right renal upper pole tumor measuring 8.4x5.2cm with level I IVC thrombus (Figure-1). There were no regional lymphadenopathy and the staging scans were negative. Results: The operative time was 124 minutes and blood loss was minimal. The patient was progressed to diet on POD 1 with bowel movement on POD 2. There was no significant change in the pre and post-operative glomerular filtration rate (GFR). The surgical drain was removed on POD2. The patient was discharged well on POD 5. There were no perioperative complications. The pathology was pT3bN0M0 Fuhrman grade II clear cell RCC. Conclusions: As a conclusion, laparoscopic radical nephrectomy and IVC thrombectomy is a complex and technically demanding surgery. With advancement of surgical skills as well as technology, more cases of minimally invasive laparoscopic radical nephrectomy and IVC thrombectomy can performed to improve the perioperative outcomes of carefully selected patients in a high volume center

Laparoscopic radical nephrectomy with inferior vena cava thrombectomy: highlight of key surgical steps

ABSTRACT Objective: Vascular involvement in the form of renal vein (RV) or inferior vena cava (IVC) thrombus can be seen in 4-10% of patients presented with RCC. In patients without presence of metastasis, surgical treatment in the form of radical nephrectomy remains the treatment of choice with 5-year survival rates of 45-70%. Open surgery is still the first treatment option of choice at the moment for RCC patients with IVC thrombus. Materials and Methods: In our study, we are reporting a case of patient with RCC and level I IVC thrombus treated with laparoscopy. Our patient is a 72 years old man with underlying co-morbidity of hypertension and chronic kidney disease (CKD) presented with right-sided RCC. The CT scan done showed a large right renal upper pole tumor measuring 8.4x5.2cm with level I IVC thrombus (Figure-1). There were no regional lymphadenopathy and the staging scans were negative. Results: The operative time was 124 minutes and blood loss was minimal. The patient was progressed to diet on POD 1 with bowel movement on POD 2. There was no significant change in the pre and post-operative glomerular filtration rate (GFR). The surgical drain was removed on POD2. The patient was discharged well on POD 5. There were no perioperative complications. The pathology was pT3bN0M0 Fuhrman grade II clear cell RCC. Conclusions: As a conclusion, laparoscopic radical nephrectomy and IVC thrombectomy is a complex and technically demanding surgery. With advancement of surgical skills as well as technology, more cases of minimally invasive laparoscopic radical nephrectomy and IVC thrombectomy can performed to improve the perioperative outcomes of carefully selected patients in a high volume center