TALD deposits thin films layer by layer by inducing self limiting chemical reactions on the substrate surface by alternately introducing two or more precursor gases. Each complete sedimentary cycle consists of four steps:
Introduce the first precursor gas: causing it to undergo chemical adsorption with the substrate surface, forming a monolayer adsorption.
Inert gas purging: Remove excess precursors and by-products to avoid gas-phase reactions.
Introduce the second precursor gas: react with the adsorbed first precursor to generate a single atomic layer thin film.
Inert gas purge again: remove unreacted precursors and by-products, prepare for the next cycle.
Thermal atomic layer deposition involves the alternating introduction of two precursor gases (such as trimethylaluminum and water vapor), which undergo chemical adsorption and surface reactions on the substrate surface, forming a single atomic layer. After each reaction, it is necessary to clean the unreacted precursor with inert gas (such as nitrogen) to ensure the self limitation of the deposition process and avoid excessive reaction.
Cleaning and Pollution Prevention of Reaction Rooms
Immediately clean the reaction chamber after each use, wipe the inner wall with a dust-free cloth and specialized cleaning agent, and focus on cleaning areas such as nozzles and substrate tables that are prone to scale buildup to avoid precursor residue or particle deposition affecting film performance.
When not in use for a long time, the pipeline should be emptied and purged with inert gas to prevent residual corrosion of the pipeline.
Maintenance focus
Precursor management: Precursors are prone to hydrolysis/oxidation and need to be stored in a sealed manner. They should be replaced regularly to avoid a decrease in purity;
Cleaning of reaction chamber: After deposition, residual precursors are prone to form deposits, which need to be cleaned regularly with plasma (such as O ₂ plasma) or chemical cleaning solution;
Pipeline leak detection: Ensure that the gas pipeline is leak free to avoid blockage caused by precursor mixing reaction;
Vacuum system maintenance: Regularly replace the vacuum pump oil, clean the vacuum gauge, and ensure stable vacuum degree.