How PVD works
Physical vapor deposition (PVD) is a thin film deposition technique used to create coatings or thin films on substrates in a variety of industries, including semiconductor, optics, aerospace, and automotive. In PVD, material is transferred from a solid (target/source) to a substrate in a vacuum environment, without going through a liquid phase.
Basics of PVD
PVD takes place in a vacuum chamber to eliminate the presence of air and other contaminants, ensuring the purity and quality of the deposited films. There are two main methods used in PVD: evaporation and sputtering.
Evaporation: In this method, the material to be deposited is heated until it reaches its vaporization temperature, causing atoms or molecules to be released into the vacuum chamber. These vaporized particles then condense onto the substrate, forming a thin film.
Sputtering: Sputtering involves bombarding a solid target material with energetic ions, typically from a plasma, causing atoms from the target to be ejected. These ejected atoms deposit onto the substrate, forming a thin film. Magnetron sputtering is a common variant of this process, which uses a magnetic field to enhance efficiency and control the deposition.
The substrate onto which the thin film is deposited is carefully prepared to ensure good adhesion and desired properties of the thin film. This may involve cleaning, preheating, or applying a seed layer. During deposition, the film thickness, composition, and other properties can be controlled by adjusting parameters such as power, substrate temperature, and pressure. PVD is used to deposit a wide range of materials, including metals, semiconductors, ceramics, and polymers, onto various substrates such as glass, silicon, metals, and plastics. It finds applications in diverse fields such as electronics, optics, packaging, automotive, medical devices, and decorative coatings. PVD offers several advantages over other deposition techniques, including high purity, precise control over film thickness and composition, excellent adhesion, uniformity, and the ability to coat complex shapes and small features. Despite its versatility, PVD also has limitations, such as restricted deposition rates compared to some other techniques and limitations on the types of materials that can be deposited.