The removal rate of slurry is the key factor in chemical mechanical planarization (CMP) for through-silicon vias copper film. Currently, in the study of slurry, the synergistic effect of some additives can produce the effect of “1+1>2”. It is widely used in semiconductor and microelectronics industries to develop novel slurry. Here, ammonium citrates served as a crucial chemical additive in through silicon via Cu film slurries. Through electrochemical measurements, X-ray photoelectron spectroscopy, ultraviolet-visible, and LSCM tests, it was revealed that ammonium citrates could react with cupric ions to form a stable water-soluble Cu-ammonium citrates complex, which can accelerate the chemical dissolution of Cu surface during the CMP process, and it was also found that the complexing effect was weaker than glycine. Moreover, various tests on Cu wafers showed that a high Cu removal rate and ideal surface quality could be realized when ammonium citrates were used as an auxiliary complexing agent in glycine-based Cu film slurries. The purpose of the study is to find an auxiliary chemical additive that can improve the performance of slurry in the manufacturing process of Cu film and other materials used in integrated circuits.
Thermodynamic simulation of a two-stage expansion air-powered engine was established and working process simulation was conducted based on this model. The effects of inlet pressure (0.8Mpa-3.0Mpa), intake duration angle of second-stage (100°CA-160°CA) and cylinder diameter of second-stage (120mm-200mm) on the gas temperature, pressure and output torque were analyzed. The results show that effective power and output torque both increase with the increase of above three parameters, meanwhile effective gas consumption rate decreases.
A reduced chemical kinetic model (103species and 468 reactions) for new low-RON(research octane number) gasoline surrogate fuels has been proposed. Simulations explored for ignition delay time have been compared with experimental data in shock tubes at pressure of 10atm-55 atm and temperatue of 600-1400 K (fuel/air equivalence ratio=0.5,1.0,2.0 and EGR rate=0, 20%). The simulation data presented 15% enlargement compared with experiments showed applicability of the new kinetic mode in this work. A combustion simulation model has been build for HCCI(homogeneous charge compression ignition) engine with Chemkin-pro. The effects of different air inlet temperature, inlet pressure, engine speed and the fuel air equivalence ratio on the combustion characteristics of the fuel were researched. The results indicated the combustion in an HCCI engine worked sufficiently with lean mixtures and low speed. Meanwhile the material strength could be influenced when the inlet conditions changed. This helps to promote the low-RON gasoline surrogate fuel application in the HCCI engine.
Copper(Cu) has been an interconnect material widely used in giant-large scale integrated circuits (GLSI). Corrosion inhibition is a key factor to ensure global planarization of Cu in the chemical mechanical planarization slurry. Here, three selected inhibitors BTA(Benzotriazole), TAZ(1,2,4-triazole), and MBO( 2-Benzoxazolethione) were investigated for their inhibition behaviors and synergy on the Cu surface. The results show that they are all effective Cu inhibitors in alkaline solutions. MBO loses its inhibition ability in H2O2, but BTA and TAZ do not. The calculated synergistic parameters of BTA/TAZ is 0.1763, X-ray photoelectron spectroscopy, and UV-Via experiments show that the antagonism between them is caused by two competitive reactions due to the similar adsorption mechanism: one is the competition for the adsorption site on the surface, and the other is the competition of copper ions that affects the formation of Cu(I)-BTA. The calculated synergistic parameter of BTA/MBO is 1.7763, the synergy between them is obvious.
The simulation method was used to study the fuel supply and injection characteristics of diesel top clearance plunger pump. The results show that the top clearance plunger pump relative advance of fuel supply is larger than that of the traditional plunger, and it can achieve the purpose of injection advance when the oil pump operate at 600~1000rpm. Through optimizing the structure of top clearance plunger, the amount of the injection advance can become larger and the advanced range of speed is increased. After optimized, the BSFC (Brake Specific Fuel Consumption) is 4.3% lower than that before when the diesel engine matched the top clearance plunger, which shows its advantage especially in working at high-speed.
The simulation results shows that pilot injection, intake preheating, main injection advance angle have a big impact on ignition performance of diesel engine. After using pilot injection, the average cylinder pressure and temperature, and the accumulated heat release increased, ultimately the fuel efficiency had been improved. By using the intake preheating, combustion efficiency had been improved for combustible mixture gas formed easily and combustion conditions significantly improved in cylinder. Besides, an appropriate main injection advance angle could improve the combustion of ignition delay period and increased the engine power and fuel efficiency.
Three-dimensional modeling and finite element analysis on the diesel engine piston is carried out in the paper. The distribution of temperature, stress and strain within piston at the rated conditions of the engine are obtained from the simulation. The calculated temperature is consistent with the results of the piston surface temperature which is obtained by hardness plug method, thus confirming the model's validity. The calculated maximum temperature is 374 °C and the minimum temperature is 144 °C. The maximum stress is 118MPa located between the piston skirt above the pin hole and the third ring groove. The maximum thermal strain appears at the piston top with the value of 6.29×10-3. Finally, the temperature simulation of the piston adopted oil-splashing cooling is implemented. It is proved that thermal load can be further reduced through cooling measure.
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