What is the working principle of CVD equipment?

The working principle of CVD (Chemical Vapor Deposition) equipment is mainly based on the chemical reaction of gaseous or vapor substances at the gas phase or gas-solid interface, generating solid deposits and depositing them on the substrate surface. The following is a detailed explanation of the working principle of CVD equipment:
1. Basic principles
CVD technology utilizes chemical reactions between gaseous reactants under high temperature conditions to form solid thin films on the surface of the substrate. This process involves the diffusion of reaction gases towards the substrate surface, the adsorption of gases on the substrate surface, the formation of solid deposits through chemical reactions, and the detachment of gas-phase by-products.
2. Core components and their roles
Reaction chamber: As a place where chemical reactions occur, the reaction chamber usually has a high vacuum or low pressure environment to ensure sufficient mixing and uniform deposition of reactants. Its internal materials and design need to be resistant to high temperatures and corrosion, in order to withstand the high temperatures and corrosive gases during the reaction process.
Heating system: used to heat the substrate to the desired temperature to activate surface atoms and promote chemical reactions. The heating methods include resistance heating, induction heating, etc., and the specific choice depends on the material and process requirements.
Gas path system: responsible for transporting reactants and carrier gas to the reaction chamber, and accurately controlling the flow rate and proportion of gases. By precisely controlling the flow rate and proportion of gas, effective control of film quality can be achieved.
Exhaust system: used to eliminate the exhaust gas and by-products generated during the reaction process, in order to maintain the cleanliness and safety of the interior of the reaction chamber. The exhaust system usually includes exhaust pipes, absorption devices, and filters.
Control system: Overall control of equipment, including setting and adjusting parameters such as heating temperature, gas flow rate, pressure, etc. Through the control system, precise control and monitoring of the CVD process can be achieved.
3. Workflow
Pre treatment: Clean and surface activate the substrate before deposition to improve the adhesion and growth quality of the film.
Heating: Start the heating system to heat the substrate to the desired temperature.
Ventilation: Open the gas path system and introduce the reactants and carrier gas into the reaction chamber.
Deposition: Under heating and ventilation conditions, reactants undergo chemical reactions on the surface of the substrate, gradually depositing into a film.
Cooling and removal: After the deposition is completed, turn off the heating system to allow the substrate to cool naturally to room temperature, and then remove the substrate.
4. Advantages and Applications
CVD technology has the advantages of high film quality, controllable composition and thickness, and good process repeatability. It has a wide range of applications in semiconductor manufacturing, microelectronics industry, materials science and other fields. For example, in semiconductor device manufacturing, CVD technology can be used to deposit thin films of metals, oxides, etc., to achieve device interconnection, protection, and functionality; In the microelectronics industry, CVD technology can be used to prepare insulation layers, conductive layers, etc. in microelectronic devices, improving the performance and reliability of the devices.
In summary, CVD equipment achieves material modification, functionalization, or protection by precisely controlling reaction conditions and utilizing chemical reactions between gaseous reactants to deposit solid thin films on the substrate surface. Its working principle is simple and effective, and it has broad application prospects in multiple fields.