As feature dimension of integrated circuits (IC) come into nanometer nodes, yield problems caused by random defects get worse. Even with advanced process techniques, the yield could not achieve 100%. Accurate prediction of yield can point out the direction of process optimization, shorten the production cycle, reduce the production cost, and then increase profits. In this paper, some kinds of random defects which can influence random yield are summarized. Then some widely used yield models are outlined and the drawbacks of these models are analyzed. At last, an improved yield model is proposed with the combination of Poisson model and negative binominal model. This model which takes distributions of random defects into consideration is more flexible and accurate. It can be seen from the simulation results that comparing to those existing models, the improved model indeed has higher fidelity and more flexibility.
Electromagnetic ultrasonic nondestructive testing technology, which it have the advantages of withstand high temperature and without coupling agent,is widely used in Nondestructive Testing (NDT) field. To effectively detect the defects, the dispersion characteristics and multimode of guided waves in the plate are studied by the disperse simulation software, and the variation of dispersion curve is analyzed by the geometric parameters and materials of plate. The results showed that the dispersion characteristics of guided wave in the plate is depended on the thickness and material of plate, and dispersion and the multimode characteristics of plate are better at low frequencies and smaller thickness. This is helpful to selection of Electromagnetic acoustic transducer (EMAT) parameter and detection operating point of guided wave.
This paper chose triadimenol as a corrosion inhibitor of copper in 0.5mol/L sulfuric acid. The properties of corrosion inhibition were investigated by the polarization measurement and electrochemical impedance spectroscopy (EIS). Polarization curves showed that both cathodic and anodic processes of copper corrosion were suppressed. The inhibiting efficiency increased as the increment of the inhibitor concentration and reached 86.7% at 50 mg/L. The results obtained from EIS measurements are in line with that obtained from potentiodynamic polarization. Finally, a mechanism of inhibition is proposed and discussed.
In the process of integrated circuit design and manufacturing, dummy metal fill can improve the planarity of layout after Chemical Mechanical Polishing (CMP). However, it will also cause lithography distortion and Critical Area (CA) variation. This paper compares and analyzes the influences of lithography distortion due to metal fill on CA from the perspectives of different defect particles based on 45nm technology node. The results indicate that dummy metal fill can increase open CA after lithography and the defect particle with the diameter of 0.066um leads to the largest increment percentage of open CA, which will take up almost 10%. This paper is instructive in researching dummy metal fill and CA or related fields in the future.
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