How to etch of single crystal aluminium?5 answersTo etch single crystal aluminum, various methods can be employed based on different research findings. One method involves ultrasonic and immersion cleaning with organic solvents, followed by chemical etching at 300 to 400°C, rinsing with deionized water, and drying the wafer. Another approach includes forming an aluminum layer on a silicon wafer, using a photoresist mask, and etching the aluminum layer with plasmas of specific gases, followed by a second gas treatment to remove the mask. Additionally, a method utilizes a photoetching adhesive layer to create a T-shaped pattern for etching aluminum, reducing corrosion by increasing polymer generation during the process. These methods offer efficient and controlled ways to etch single crystal aluminum while minimizing corrosion and enhancing process controllability.
When etch AZO(ZnO:Al), what is the best solution?5 answersThe best solution for etching AZO (ZnO:Al) thin films depends on the specific requirements of the application. Different etching solutions offer varying advantages. For controlled vertical and lateral etching of ZnO, new buffer solutions have been developed, providing uniform and reproducible etching results. On the other hand, an AZO film etching solution with excellent performance characteristics has been introduced, offering low cost, safety, and environmental friendliness while effectively controlling properties like etching rate and CD loss. Additionally, chemical etching using Molybdenum etch solution has shown promising results for patterning AZO thin films for MEMS applications, with low undercut etching and high effectiveness in lateral and vertical etching, making it a viable option for specific patterning needs.
How does the chemical etch rate vary with changes in temperature?4 answersThe chemical etch rate of silicon can vary with changes in temperature. In the wet chemical etching of silicon using concentrated HF-HNO3 and HF-HNO3-H2SiF6 mixtures, a significant temperature increase during the etching process can lead to an increase in the etch rate. This increase in temperature also changes the concentrations of dissolved nitrogen oxides and intermediary species, resulting in a change in the overall reaction process. Similarly, in the high-rate etching of Si by narrow-gap microwave hydrogen plasma, the etch rate strongly depends on the surface temperature. The optimum temperature for high-rate etching is about 70 °C, and an increase in temperature above this value leads to a decrease in etch rate. Additionally, in the etching of silicon dioxide using chlorine trifluoride gas, the etch rate tends to approach a constant value at temperatures exceeding 1173 K. Therefore, the etch rate of silicon can be influenced by temperature changes in different etching processes.
How to etch Mo with ALE method?4 answersAtomic layer etching (ALE) of Mo can be achieved using a two-step process. In the first step, the Mo surface is fluorinated using CHF3 or C4F8 plasmas, resulting in the formation of a fluorine-rich fluorocarbon layer. This fluorinated Mo surface is then etched using Ar plasma. Another approach involves a sequential plasma oxidation and chlorination process. In the oxidation step, Mo is oxidized with oxygen plasma to form molybdenum oxide, and in the chlorination step, the molybdenum oxide is removed by forming molybdenum oxychloride in chlorine plasma. Additionally, a novel sequential etching method involving an oxidation step in ozone followed by selective oxide dissolution has been proposed for Mo etching. These methods offer improved etch-rate control, reduced surface roughness, and the ability to etch Mo in small dimensions.
What is the current status of plasma etching?5 answersPlasma etching is a widely used technology in the semiconductor industry for transferring patterns defined by lithography onto materials. It has been instrumental in achieving smaller dimensions, reducing sidewall roughness, and enabling multiple patterning. Plasma-chemical etching is the primary method for transferring integrated circuit patterns onto substrates, and the requirements for plasma technology are becoming more stringent. Plasma etching processes involve alternating etching and protective film forming steps, and there is a need to reduce greenhouse gas emissions without compromising etching processing characteristics. A plasma etching method using iodine heptafluoride as the etching gas has been developed to achieve a high etching rate of silicon nitride films. Plasma etching has revolutionized integrated circuit manufacturing by allowing anisotropic etching of various materials, such as silicon, aluminum, and silicon dioxide, in plasmas. The field of plasma etching continues to evolve, with ongoing research and advancements in reactor design, etching mechanisms, and applications in silicon integrated circuit fabrication.
What are the drawbacks of etching the MAX phase with HF acid?5 answersEtching the MAX phase with HF acid has several drawbacks. Firstly, HF acid is hazardous to humans and the environment, making it a safety concern. Secondly, the etching process using HF acid can result in the loss of certain species, such as aluminum, from the material being etched. This loss of species can affect the properties and composition of the material. Additionally, the etching rate of HF acid can vary depending on the orientation of the material, with etching through the edges being isotropic and more pronounced than etching through the basal planes. Lastly, HF etching can lead to the restructuring of the surface of the material being etched, which can affect subsequent processes, such as oxidation, and result in the formation of different compounds.