Damage Behavior in Simulated Service Environment of Thermal Control Oxidation Film of 2A12 Alloy

In order to obtain the service performance of the black anodic oxidation film of 2A12 aluminum alloy, the influence of humidity and temperature in storage environment and heat on the performance of black oxidation film were studied. And the morphologies were analyzed by using optical microscopy (OM) and scanning electron microscopy (SEM). The results showed that after the black anodic oxidation film is produced, "aging" will occur in the natural environment, which can lead to the structure change of the sealing pore and affect the service performance of the film. The film exfoliates off slightly under the humidity of 90%, and the film exfoliates off more seriously when the humidity over 95%. The temperature has a greater influence on the film cracking, especially when the temperature is above 120°C, it is easy to exfoliate off. The exfoliation model was established and the affection mechanism was discussed.

Mechanics of Periodic Film Cracking in Bilayer Structures Under Stretching

In a bilayer structure consisting of a stiff film bonded to a soft substrate, the stress in the film is much larger when the rigidity of the film is much higher than that of the substrate so that film cracking is a common phenomenon in bilayer structures such as flexible electronics and biological tissues. In this paper, a theoretical model is developed to analyze the normal stress distribution in the structure to explain the mechanism of the formation of periodic crack patterns. The effects of geometrical and material parameters are systematically discussed. The analytical result agrees well with finite element analysis, and the prediction of spacing between cracks agrees with experiments from the literature.

Pre-particle filtration and moisture control by efficient purging in various inlet and outlet of a 450 mm wafer front-opening unified pod

The trend toward narrower line width in semiconductor manufacturing has made contamination control more and more important. The presence of moisture in wafer containers, such as front opening unified pods (FOUP), can lead to the native oxide residues growth, metal corrosion, and thin film cracking on wafer surfaces. Accordingly, decreasing contamination methods and improving factory efficiency are continuously researched. Single or multi-layer particulate shields on top of wafers in FOUPs may be used to prevent pollutant accumulation. In addition, point-of-use (POU) filtration may also been used to control particle contamination in FOUPs during wafer transformation and storage. The demand for stricter filtration led to the usage of 0.10 and 0.20 µm membranes to control the contamination. However, with the introduction of finer membranes end users may have concerns about deleterious remainders on wafers from undergoing filtration. There are a total of 25 pieces of wafers in the FOUP and the arrangement is from the bottom (wafer No. 1) to the top (wafer No. 25) with arising manner. Purging FOUPs to expel moisture vapors with Clean Dry Air (CDA) is one of the most popular methods.There was no previous research for investigating the purge performance on new-generation 450mm FOUPs. This research aims to study main factors influencing the performance of the purge system on 450mm FOUPs, including moisture concentration, CDA flow rate, and filter pressure.

Thermo-Mechanical Coupled and Fracture in Diamond Film under High Strain Rate

According to the special case of high strain rate for diamond film produced by DC plasma jet method, a transient thermo-mechanical coupled model for the cooling process of diamond film and Mo substrate was developed. The direct coupled finite element method was used to simulate the transient thermal stresses in diamond film during the cooling period after the film deposition. The residual thermal stresses of diamond film were calculated and compared respectively under two conditions of real uneven temperature fields and unreal even temperature fields. Based on the simulated results of stresses, the moment and cause of diamond film cracking were analyzed. The conclusions are as the follows: (1) the thermal stresses in diamond film increase with the increase of cooling time, but the maximum first principal tensile stress may reach the fracture strength of common diamond film before the film cools to room temperature; (2) the excessive tensile stress at the film edge causes the film cracking; (3) in order to reduce the thermal (residual ) stresses and increase the finished product ratio of diamond film, it is essential to further improve the temperature uniformity.

Microstructure and Wear-Resistant SiC Film by RF Magnetron Sputtering

A wear-resistant SiC (silicon carbon) film on titanium substrate was prepared by magnetron sputtering technology. The film exhibits low nano-hardness of 12.1 GPa and low Young's modulus of 166.2 GPa together with superior friction/wear properties. As sliding against Si3N4 (silicon nitride) ball (2 mm in radius) at room temperature under Kokubo simulation body fluid condition, the film exhibited the friction coefficient of about 0.215 and the special wear rate in the order of magnitude of 10−5 mm3/ Nm even at the load of 500g without film cracking and interface delaminating. The high film-cracking and interface-delaminating resistance is due to the low hardness of the film and the good film/substrate modulus match caused by the low elastic modulus of the film.