Etching characteristics of si wafer thinning in HF/H2O binary solution for microelectronic and nanopackaging applications

The wet etching of silicon surfaces by the use of acidic or fluoride solutions is of both technological and fundamental significance, which is essentially to be applied to produce a reliable silicon chip at desired thickness for microelectronic packaging. In this work, we have investigated the wet etching effect on thickness dissipation, weight loss, etching rate, surface morphology and crystalline nature of Si wafer immersed in the 48 % HF/water solution. The etch rate was ascertained from the variation of weight loss and depth etched against time. The results show that the thickness reduction and weight loss of silicon increases as the etching time increases. Roughened surface is observed on the etched Si wafer surface under the high-resolution optical microscope. From the XRD analysis, it shows that the crystalline peak intensity of silicon becomes weaker after etching, implying the reduced light scattering from the formed amorphous structure surface on the Si substrate. After all, this finding can be valuably referred to produce a reliable Si thin wafer, which is crucial in thinner microelectronic devices fabrication and nanopackaging, and in turn reduces environmental pollution and energy consumption for future sustainability.