In semiconductor manufacturing, thin films of aluminum are typically deposited onto chip surfaces using metal sputtering (sputtering) technology. Sputtering is a physical vapor deposition (PVD) process, which strikes a metal target by using the ionization and acceleration of inert gases such as ** argon (Ar)**, causing the atoms on the target to splash out and deposit onto the surface of the wafer to be processed.
1. Basic principle of sputtering
The core of the sputtering process is the use of argon ions (Ar +) accelerated at high voltage, hitting the surface of the aluminum target. When the argon ions hit the aluminum target, the aluminum atoms are stripped from the surface of the target and sputtered onto the surface of the wafer. The thickness, uniformity and quality of the aluminum film can be controlled by adjusting parameters such as the gas flow rate, the voltage of the target and the deposition time.
2. Advantages of the sputtering process
High precision: Sputtering technology can precisely control the thickness and deposition rate of aluminum films, which is suitable for fine semiconductor manufacturing.
Low-temperature deposition: The sputtering process has a lower deposition temperature compared to chemical vapor deposition (CVD) and therefore avoids high temperature damage to the material, making it particularly suitable for temperature-sensitive processes.
Good film quality: By optimizing the sputtering conditions, the aluminum film can have good adhesion and flatness for subsequent processing.