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Cu-to-Cu direct bonding is one of the key technologies for 3D (three-dimensional) chip stacking. This research proposes a new concept to enhance Cu-Cu direct bonding through the control of residual stresses on bonding surface. Compressive residual stress induced by near-infrared radiation (NIR) enhances the diffusion of copper atoms and thus direct bonding. Subjected to thermal compression bonding...
It has been proposed that Cu-Ag alloys exhibit longer eletromigration life time than Cu as well as superior electrochemical migration resistance than Ag. Our group developed a new kind of Cu-Ag composite paste which is capable of achieving bonding at low processing temperatures under low bonding pressure. It comprises carboxylate-coated Ag nanoparticles, spary-pyrolyz ed Ag submicron particles and...
An innovative pre-treatment to enhance Cu-to-Cu bonding through the exposure of electromagnetic radiations including flash light and near infrared rays is first proposed in this study. Short period of electromagnetic radiation exposure can significantly improve the bonding strength. It can be ascribed to the sudden heating/cooling and thus compressive residual stresses which enhance the diffusion...
The sealing and contact bonding of IMU (inertial measurement unit) are important procedures in the MEMS device fabrication. Conventional process is Al-Ge eutectic bonding developed by InvenSense, for which the process temperature is above 450°C and the bonding time is longer than 1 hr. This study proposes an innovative and efficient process combined with an air plasma bombardment and a following catalyzed...
One of the trends in microelectronics fabrication is to manufacture highly conductive interconnections at a low processing temperature using metallic nanoparticles. In order to obtain excellent electrical conductivity, the surfactants have to be removed and the particles should be well linked. With the assistance of chemical reductants and radiations of flash UV light and near IR, carboxylated-protected...
Schizophrenia has been considered as a dysconneciton syndrome, which means the disintegration, or over interaction between brain regions may underlie the pathophysiology of this disease. Noninvasive techniques like functional magnetic resonance imaging (fMRI) were utilized to test this hypothesis. However, there is no consensus on which brain areas and which functional network is related with it,...
The combination of excellent electrical conductivity (only 6% less than Ag) and low cost makes copper a good selection for interconnect materials. However, rapid oxidation of Cu nano particles is a fatal demerit. In order to improve the oxidation resistance, Cu-Ag composite particles are developed for the bonding and interconnect applications in this study. To cut the cost and realized mass production,...
Taking the advantage of high specific surface area, fine silver particles were recently attract much attention since they can be sintered as conductive circuits or joints at relatively low processing temperatures. Although various methods have been applied to produce silver particles, the spray pyrolysis (SP) process has an advantage in its low cost and feasibility for mass production. In this study,...
In this study, silver acetate was used as the precursor to synthesize submicron-sized Ag particles using thermal-spary pyrolysis method at relatively low processing temperatures. Pastes mixed with submicron particles thus produced were sintered at 100°C or 250°C to form conductive circuits. Critical current to fuse was measured to evaluate the interconnect reliability under high electric current stressing...
A method is presented to segment brain tumors in multi-parametric MR images via robustly propagating reliable statistical tumor information which is extracted from training tumor images using a support vector machine (SVM) classification method. The propagation of reliable statistical tumor information is implemented using a graph theoretic approach to achieve tumor segmentation with local and global...
This study investigated the effect of pretreatments including annealing and air plasma irradiation, on the surface roughness and mechanical properties in the subsurface region of Cu blocks, as well as joint strength of directly-bonded samples. Remarkably, high temperature annealing caused a significant reduction in joint strength, which could mainly attributed to rugged bonding surface. Rather than...
This study developed a low temperature soild-state direct bonding process for dissimilar metals. Experimental results show that Cu/Zn can be bonded successfully at 200°C under the loading of 10MPa for 30 minutes. The joints thus formed exhibited a shear strength up to 20MPa. If the thermal compression was performed at 300°C, the shear strength of bonded Cu/Zn and Cu/Ni/Zn joints exceeded 50MPa, especially...
Taking the advantage of low sintering temperature and high processing flexibility, metallic nanoparticles (NPs) have been widely used to fabricate interconnections. To obtain excellent electrical conductivity, the surfactants protecting the nanoparticles have to be removed thermally and thus the particles can be well linked. Considering the interconnect fabrication on flexible substrates (usually...
Eletrochemical corrosion properties of Cu and Ag in the aqueous solutions of reducing agents of formic acid, glycol and ascorbic acid with various concentrations were examined respectively. Experimental results show that there exists no passivation stage on the polarization curves of Cu and Ag in those reductive solutions. Ascorbic acid corrodes Ag faster than the otherss, while formic acid is most...
As functional magnetic resonance imaging (fMRI) studies have yielded increasing amounts of information about the brain’s spontaneous activity, they have revealed fMRI’s potential to locate changes in brain hemodynamics in neuropsychiatric disorders. In this paper, we review studies that support the notion that changes in spontaneous low-frequency fluctuation (SLFF) observed by fMRI can be used as...
We discuss the prompt emission of gamma-ray bursts (GRBs), allowing for γγ pair production and synchrotron self-absorption. The observed hard spectra suggest heavy pair-loading in GRBs. The re-emission of the generated pairs results in the energy transmission from high-energy gamma-rays to long-wavelength radiation. Due to strong self-absorption, the synchrotron radiation by pairs is in optically...
This paper introduces intelligent control of LED lighting by using the Doppler circuit to detect the moving people and vehicles. Visible light communication (VLC) is activated by the opening of LED. STM32 can process Doppler signals and judge the necessity of communication according to the time of day or night to guarantee the intelligent switch of LED and green communication. The paper describes...
In this paper, we mainly study the key technical issues of Network-on-Chip (NoC), focusing on the analysis of typical NoC mapping problems, and making further research on the fault-aware NoC task mapping. Firstly, we study some critical problems in the design of NoC task mapping, then summarized a fault model, and finally, verified the related issues of NoC on verification platform and Field Programmable...
The principle of the lever type anti-resonant inertial resonant machine was analyzed, and the expression of the upper and lower mass body under anti-resonant inertial resonant machine was derived. Based on the anti-resonance theory, the anti-resonant frequency and dynamic load transmit rate of the resonant vibration isolation system have been obtained, meanwhile the parameters of the system was analyzed...
This paper explores the retailer's optimal strategies and the manufacturer's warranty period decision from a three-stage game theoretic perspective. The market demand is related to the warranty period and the price of the product. The Stackelberg game is modeled with the retailer as the game leader. Assuming that the warranty cost is private information of the manufacture, the retailer uses a menu...
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