Papers by Keyword: Scratch

Abstract: The influence of seed preparation on crystal defect generation is studied by investigating the effect of damage from surface scratches not completely removed during polishing on the seed crystal on the nucleation and evolution of dislocation arrays. Synchrotron X-ray topography is conducted on several wafers sliced from a PVT-grown 4H-SiC boule. Topographic results in conjunction with ray tracing simulation reveal the generation of TSD/TMD and TED arrays associated with the scratches in the newly grown wafer adjacent to the seed. Configuration transformation of those arrays is observed as these opposite-signed dislocation pairs composing the arrays were affected by the overgrowth of macro-steps when propagating into the newly grown crystal.

Abstract: Wafer scratching from handling and processing can impact the performance of devices grown on a substrate. Knowledge of process conditions and modeling of scratches on wafers can be used to elucidate the root cause of scratches so that they can be eliminated.

Abstract: The experiment of cutting mechanical properties of single crystal silicon surface in the micro-nanoscale is researched using nanoindenter and atomic force microscopy. The result of the experiment shows that: in the constant load, the impact of different scratching velocity for single crystal silicon surface scratch groove width and chip accumulation volume are not big; but the cutting force and friction coefficient are not increases with the scratching velocity increases; when the scratching speed is certain, the size of load has a greater impact on the cutting mechanical properties of single crystal silicon surface, with the increase of the load, the cutting force increases, but the cutting force is not linearly growth.

Abstract: This paper is devoted to investigate an estimation methodology of micro hardness and Young’s modulus of reacted passivation layer of deposited copper thin film in dry and wet environment based a tip-grit atomic force microscope (TGAFM) scratch on copper thin film of silicon wafer. The TGAFM is a modification or attachment of a nanoor micron grit on the tip apex or cantilever beam of a closed-loop control AFM instrument. In this study, a diameter 800 nm SiO₂ grit glued on the apex of the tip of AFM is used for experiment. Tip force model has been developed based on Hertzian model and Tresca criterion for stress-strain relationship from the geometries of scratch groove, depth and width to evaluate about microhardness and Young's modulus of copper thin film in regular air and DI-water. Experimental results show that the microhardness (H) is 1.62GPa and the Young's modulus (E) is 160.52GPa of copper thin film in DI-water environment. These mechanical properties of copper thin film is larger than the H= 1.52GPa and E= 126.04GPa for dry environment. Results of this study can be further explored to the grit force reaction on the passivation layer of copper film of chemical mechanical planarization (CMP) process development for semiconductor industry.

Abstract: Titanium alloy structure is an indispensable structure in aviation industry. It has high sensitivities for gap, scratch and other surface defects. Therefore, it is easy to produce various damages, such as crack, scratch and break. This paper describes a new laser rapid repair system which solves the technical problem that modern aviation titanium alloy components can not be repaired by conventional repair techniques. The rapid repair for titanium alloy components can be achieved by means of it. Meanwhile, the repair quality of aviation titanium alloy structure can be improved.

Abstract: In this paper, material removal mechanism of monocrystalline silicon by chemical etching with different solutions were studied to find effective oxidant and stabilizer. Material removal mechanism by mechanical loads was analyzed based on the measured acoustic signals in the scratching processes and the observation on the scratched surfaces of silicon wafers. The chemical mechanical polishing (CMP) processes of monocrystalline silicon wafers were analyzed in detail according to the observation and measurement of the polished surfaces with XRD. The results show that H₂O₂ is effective oxidant and KOH stabilizer. In a certain range, the higher concentration of oxidant, the higher material removal rate; the higher the polishing liquid PH value, the higher material removal rate. The polishing pressure is an important factor to obtain ultra-smooth surface without damage. Experimental results obtained silicon polishing pressure shall not exceed 42.5kPa.

Abstract: Lead-free piezoelectric (Bi_1/2Na_1/2)TiO₃ (BNT) films were deposited on 0.2 mm thick pure titanium (Ti) substrates by a hydrothermal method. Scratch tests were performed to quantitatively assess the adhesion strength between BNT films and Ti substrates. Ti substrates were pretreated by chemical polish and mechanical polish respectively prior to BNT film deposition with a view of investigating the effects of substrate surface pretreatments on the adhesion of BNT film. In the scratch test, the behaviour of BNT film exfoliation was investigated by SEM observation. The scratch test results revealed that the chemical polish pretreatment effectively improved the adhesion of BNT films.

Abstract: The Integrated Evaluation Platform for SiC wafers and epitaxial films is established and provide TDDB reliability data such as Q_bd. Accumulated numerous Q_bd data derived from the platform shows three discrete universal distributions (D1>D2>D3) mainly affected by step bunching. On the fairly flat surface, locally spreading step-bunching area formation is caused by the scratches on the CMP surface. The step-bunching area contains large number of step-bunching lines, which correspond to trapezoid-shape defects, stretching in a low along the scratches. Only the downstream bases of the trapezoid-shape defects degrade the Q_bd into D2 from D1 on the flat surface without step bunching.

Abstract: Scratch tests on (001) face, doubler face and tripler face of KDP crystals are carried out at room temperature. It shows that the friction ceoffcients of different crystal faces are affected seriously by the crystal oritations, their variation periods of (001) face, doubler face and tripler face are 90^o, 180^o and 180^o, their attitudes of relative anisotropy are 50%, 43.8% and 43.8%, and all of them are less than 0.4. The scratch mechanism of KDP crystal consists of four types: elastic and plastic deformation, ploughing, microchip, and surface damage. Differences between elastic and plastic deformation and ploughing are not obvious due to the soft-brittle nature of KDP crystal.

Abstract: In order to improve the detection precision and speed of train wheel image,it is necessary to research digital image processing technology.In this paper,a kind of appropriate image filtering method,combination of smoothing and sharpening,and a kind of appropriate edge detection method,combination directly and by column in binarization,were introduced.A clear image of wheel surface can be obtained.The method of detection of scratch was designed.Non-contact measurement of train wheel surface quality can be realized,it will lead to the detection speed is faster, accuracy is higher.