The production of silicon wafers usually includes the following main processes:
1. Single crystal silicon growth: through chemical vapor deposition (CVD) or single crystal silicon floating zone method. Silicon materials are grown in the form of single crystals at high temperatures. The single-crystal silicon block produced by this step is called a silicon ingot.
2. Silicon ingot cutting: Cut the silicon ingot into thin and flat disk-shaped silicon wafers using cutting machinery or cutting technology. Common wafer diameters include 2 inches (50.8 mm), 4 inches (101.6 mm), 6 inches (152.4 mm), 8 inches (203.2 mm), and 12 inches (304.8 mm).
3. Substrate cleaning and leveling: Clean the silicon wafer to remove surface contaminants and impurities. Then perform leveling treatment to make the surface flatness of the silicon wafer meet the requirements.
4. Oxide layer formation: By placing the silicon wafer in a high-temperature oxidation furnace, it reacts with oxygen to form a silicon oxide (SiO2) film. The oxide layer can be used to protect the surface of the silicon wafer and perform functions such as insulation.
5. Photolithography: Using photolithography technology, photoresist is coated on the surface of the silicon wafer, and a specific pattern of light is projected onto the photoresist through a photolithography machine. Subsequently, a development process is performed to remove the unexposed areas of the photoresist to form a photoresist pattern.
6. Corrosion and etching: Use chemical corrosion or physical etching technology to etch or etch the surface portion of the silicon wafer that is not protected by photoresist to form specific structures and devices.
7. Doping and diffusion: Doping is done on the surface of the silicon wafer or in a specific area, and impurities are introduced through methods such as ion implantation or diffusion to adjust the conductive properties and device characteristics of the silicon wafer.
8. Metal thin film deposition: Depositing a metal thin film on the surface of a silicon wafer is usually achieved through techniques such as physical vapor deposition (PVD) or chemical vapor deposition (CVD). Metal films can be used in device structures such as electrodes, wires, and connectors.
9. Cracking: Through a specific process, silicon wafers are cracked or divided, and large-sized silicon wafers are cut into smaller silicon wafers or wafers for subsequent device preparation.
10. Cleaning and inspection: Clean the silicon wafer to remove residual impurities and contaminants. Conduct quality inspections to ensure that the quality and performance of silicon wafers meet requirements.
11. Packaging and encapsulation: Properly package and encapsulate the silicon wafer to protect the surface and structure of the silicon wafer and facilitate subsequent storage and transportation.