CVD and PVD coating processes

CVD (Chemical Vapor Deposition) and PVD (Physical Vapor Deposition) are coating processes that are often used for the surface treatment of tools and molds.

CVD – how it works

Chemical Vapor Deposition (CVD) is a coating process that produces thicker layers and is subject to comparatively high pressure and temperature. The most important application of CVD is wafer coating.

In CVD, a substrate is heated, on the surface of which a solid component is deposited from the gas phase as a result of a chemical reaction. In order to be able to deposit the solid layer at a specific reaction temperature, volatile compounds of the layer components must be present.

In contrast to physical processes, chemical vapor deposition can also be used to coat surfaces with complex three-dimensional shapes, such as the finest indentations in wafers.

Applications of chemical vapor deposition (CVD)

• Electronics industry (chip manufacture)
• Refining of glass (e.g. heat protection layers on architectural glass or protection against mechanical shock loads in bottling plants)
• optical coatings on glass and plastic
• gas-tight barrier layers
• synthetic diamond layers on tools

 PVD – how it works

PVD is based on physical vapor deposition. These are vacuum-based coating processes or thin-film technologies. In contrast to the CVD process, the layer is formed here directly by condensing a material vapor from the starting material.

Physical vapor deposition involves very low pressure (high vacuum) and comparatively low temperatures, typically resulting in very thin coatings.

PVD processes are characterized by:

• Gas (vapor) generation of the layer-forming particles
• the vapor is transported to the substrate
• and condenses on this, resulting in layer formation

Applications of physical vapor deposition (PVD)

• Industry, especially in the field of machining
• Microelectronics
• Chip Manufacturing
• Tools
• Jewellery
• Glass coating (architectural glass, displays …)
• Food industry
• Entertainment electronics (hard drives, CDs, DVDs)

High vacuum required

Physical vapor deposition only works in high vacuum because an extremely clean environment is essential for the manufacture of microchips, CDs and DVDs. Even the smallest particles are a big problem.

That is why venting a high-vacuum chamber is always a major challenge. It is important to aerate them slowly and in a controlled manner, because venting too quickly creates turbulence that stirs up particles in the chamber.

At SMC you get all the components you need for CVD processes and for ventilation and evacuation of your high-vacuum chamber for PVD processes: a wide variety of valves, temperature control units, sensors, etc.