Enhancement of Abnormal Grain Growth by Surface Quenching Treatment to Eliminate Cu-Cu Bonding Interfaces Using (111)-Oriented Nanotwinned Copper.

Cu-Cu joints have been adopted for ultra-high density of packaging for high-end devices. However, the processing temperature must be kept relatively low, preferably below 300 °C. In this study, a novel surface modification technique, quenching treatment, was applied to achieve Cu-to-Cu direct bonding using (111)-oriented nanotwinned Cu. The quenching treatment enabled grain growth across the Cu-Cu bonding interface at 275 °C. During quenching treatment, strain energy was induced in the Cu film, resulting in a wrinkled surface morphology. To analyze the strain energy, we utilized an electron backscattered diffraction system to obtain crystallographic information and confirmed it using kernel average misorientation analysis.

Enhanced Copper Bonding Interfaces by Quenching to Form Wrinkled Surfaces.

For decades, Moore's Law has been approaching its limits, posing a huge challenge for further downsizing to nanometer dimensions. A promising avenue to replace Moore's Law lies in three-dimensional integrated circuits, where Cu-Cu bonding plays a critical role. However, the atomic diffusion rate is notably low at temperatures below 300 °C, resulting in a distinct weak bonding interface, which leads to reliability issues. In this study, a quenching treatment of the Cu film surface was investigated. During the quenching treatment, strain energy was induced due to the variation in thermal expansion coefficients between the Si substrate and the Cu film, resulting in a wrinkled surface morphology on the Cu film. Grain growth was observed at the Cu-Cu bonding interface following bonding at 300 °C for 2 and 4 h. Remarkably, these procedures effectively eliminated the bonding interface.

Enhanced Nanotwinned Copper Bonding through Epoxy-Induced Copper Surface Modification.

For decades, Moore's Law has neared its limits, posing significant challenges to further scaling it down. A promising avenue for extending Moore's Law lies in three-dimensional integrated circuits (3D ICs), wherein multiple interconnected device layers are vertically bonded using Cu-Cu bonding. The primary bonding mechanism involves Cu solid diffusion bonding. However, the atomic diffusion rate is notably low at temperatures below 300 °C, maintaining a clear and distinct weak bonding interface, which, in turn, gives rise to reliability issues. In this study, a new method of surface modification using epoxy resin to form fine grains on a nanotwinned Cu film was proposed. When bonded at 250 °C, the interfacial grains grew significantly into both sides of the Cu film. When bonded at 300 °C, the interfacial grains extended extensively, eventually eliminating the original bonding interface.

IgM-anticardiolipin antibody and vascular access thrombosis in chronic hemodialysis patients.

AIM: Vascular access failure is a major cause of morbidity in chronic hemodialysis (HD) patients. Elevated immunoglobulin-M anticardiolipin antibody (IgM-aCL) titer is associated with stenosis of vascular access in HD patients. The clinical significance of elevated IgM-aCL titer relative to recurrent vascular access thrombosis (VAT) in patients with HD is less clear. However, little information has been available until now about the clinical influence of elevated IgM-aCL titer with recurrent VAT in HD patients from Western countries, and no report exists for Taiwan. This study attempted to determine whether elevated IgM-aCL titer was associated with recurrent VAT in HD patients. METHODS: This study enrolled 483 patients undergoing HD. IgM-aCL titer and hepatitis C marker were measured for all subjects. RESULTS: Elevated IgM-aCL titer was present in 17.4% (84/483) of patients. There was no association recurrent VAT between elevated and normal IgM-aCL titers (P=0.90). Presence of hepatitis C had significant differences between elevated and normal IgM-aCL titers (P=0.027). CONCLUSIONS: We found no significant differences in recurrent VAT between elevated and normal IgM-aCL titer in chronic HD patients. Our results suggest recurrent VAT of synthetic or native fistula may not be caused by elevated IgM-aCL titer in these patients. Presence of hepatitis C may be a cofactor.

Bilateral renal infarctions and lower limbs artery thrombosis in a patient with nephrotic syndrome.

Thromboembolism is a well-recognized complication in patients with nephrotic syndrome owing to their hypercoagulable status. Usually, the venous system is affected, whereas the very rare occurrence of arterial thrombosis is mainly restricted to pediatric patients. This complication often results in high rates of mortality and limb loss. We report the case of an adult female patient with histologically diagnosed minimal change disease and nephrotic syndrome associated with malignant thymoma, who eventually developed concurrent bilateral kidney and lower limb thrombosis. Conservative systemic anticoagulation was administered and she recovered ample kidney function. In addition, although she underwent an emergent thrombectomy of the left popliteal artery, an amputation was necessary. To the best of our knowledge, this is the first reported arterial thrombosis case involving bilateral kidney and lower limb simultaneously in nephrotic patients. Our experience indicates that arterial thrombosis is a serious complication in nephrotic patients, and early detection and aggressive management are crucial in these patients to improve their outcome.

Axillary artery to contralateral axillary vein graft fistula in chronic hemodialysis patients.

BACKGROUND: Vascular access failure is a severe and common complication for hemodialysis patients. The possible vascular access sites are limited in dialysis patients. Axillary artery to contralateral axillary vein arteriovenous fistula (AVF) is one of the possibilities. However, the clinical outcome of this procedure is still un-defined. OBJECT: The purpose of this study is to review the clinical outcome of axillary artery to contralateral axillary vein AVF as a hemodialysis vascular access. PATIENTS AND METHODS: We retrospectively reviewed native or graft arteriovenous fistula records for chronic hemodialysis patients at Chang Gung Memorial Hospital in Kaohsiung, Taiwan, from January 1986 to March 2001. Records were reviewed for all chronic hemodialysis patients, with more than 2000 individuals receiving more than 10,000 fistulas. Eight patients received axillary artery to contralateral axillary vein AVF. RESULTS: The mean age for these patients was 61.7 +/- 16.3 year-old at time of surgery. All patients had received multiple native or graft arteriovenous fistula creation. The 2-year and 4-year AVF graft survival is 87.5% and 43.8% respectively. One patients developed brachial plexopathy after operation. Another patient had venous hypertension distal to the AVF site. Both patients were managed conservatively. There is no AVF-related mortality in these patients. CONCLUSION: We conclude that axillary artery to contralateral axillary vein graft fistula may be a feasible alternative choice for chronic hemodialysis access.

Extra-renal abscess in chronic hemodialysis patients.

AIM: Infectious disease represents one of the major causes of morbidity and mortality in hemodialysis patients. Extra-renal abscess constitutes a specific form of infection. The aim of this study was to evaluate and analyze the clinical characteristics of extra-renal abscess in chronic hemodialysis patients. METHODS: We retrospectively studied the extra-renal abscess among chronic hemodialysis patients in Chang Gung Memorial Hospital at Kaohsiung, Taiwan. The records of 2,168 chronic hemodialysis patients from October 1986 to January 2000, were studied. The clinical features were reviewed and analyzed. RESULTS: Sixteen patients who were enrolled during the study period developed extra-renal abscess. Ten of them were male. The mean age was 59.2 +/- 11.8 years old. More than half of the patients had diabetes (53.6%, 9/16). The locations of extra-renal abscess in these patients were liver (8/16), lung (5/16), spleen (1/16), perianal region (1/16), psoas muscle (1/16), and prostate (1/16). One patient had concurrent liver and spleen abscesses. All patients presented with fever and chills. Laboratory studies revealed leukocytosis and thrombocytopenia in 2/3 of the patients. The patients were associated with malnutrition status with lower serum albumin level (2.94 +/- 0.55 gm/dL) and lower nPCR (normalized protein catabolism rate; 0.84 +/- 0.11 gm/Kg/day) comparing to the other hemodialysis patients (albumin: 4.05 +/- 0.47 gm/dL; nPCR: 1.14 +/- 0.31gm/kg/day). There was no significant difference in kt/V between the patients with (1.28 +/- 0.34) or without abscess formation (1.47 +/- 0.36). The major causative pathogen was Klebsiella pnewnoniae. Parenteral antibiotic treatment is sufficient to treat most of the diseases, except 2 patients who needed surgical intervention. Twelve patients recovered after 2-3 weeks of treatment. CONCLUSIONS: The study indicated that extra-renal abscess is rare in chronic hemodialysis patients. The abscesses occurred mostly in liver. Diabetes mellitus and poor nutrition status were the important predisposing factors. Gram-negative bacilli, K. pneumoniae, were the major pathogen. Most of the patients responded to parenteral antibiotics and surgical draining.

Treating hyponatremia in an empty sella syndrome patient complicated with possible myelinolysis.

Hyponatremia as the presenting manifestation of empty sella syndrome is rare. There is little clinical experience in the management of this problem and its possible therapeutic complications. We herein report on a 44-year-old woman with a past history of massive postpartum hemorrhage who was admitted because of hyponatremia and disturbed consciousness. Initial biochemical data suggested the effects of antidiuretic hormone, but fluid restriction alone offered limited benefit. Later, hormonal levels indicated hypopituitarism. Magnetic resonance imaging and cisternography led to a diagnosis of empty sella. Although glucocorticoid substitution was initiated and the clinical condition initially improved, possible myelinolysis subsequently became a complication. With early recognition and immediate replacement of hypotonic fluid, the patient completely recovered. We report this case to illustrate the fact that glucocorticoid substitution and concurrent fluid restriction can probably lead to myelinolysis in empty sella syndrome patients. We suggest that the serum sodium level should be frequently monitored and that much more attention should be paid to the neurologic signs when substituting glucocorticoids in these patients, even though the increment in the serum sodium level is acceptable. Once possible myelinolysis develops, early recognition is critical, and the immediate replacement of hypotonic fluid is suggested.