Introduction – Thin Film Deposition
Thin film deposition is a vacuum technique to apply coatings of pure materials onto the surface of many different objects. The coatings are composed of a single material or layers of multiple materials, with a thickness range of angstroms to microns. The object to be coated is called as the substrate, which can be a wide range of things, including semiconductor wafers, optical components, solar cells, and many other possibilities. The coating materials can be either molecules, including nitrides and oxides, or can be pure atomic elements such as both metals and non metals. There are various forms of thin film deposition available, including physical vapor deposition and sputtering. Semicore supplies a suite of high performance thin film deposition sputtering systems that provide coatings on many different materials.
Sputtering is a process wherein a controlled gas, typically chemically inert argon, is introduced into a vacuum chamber and then a cathode is electrically energized to generate a self sustaining plasma. The exposed surface of the cathode, referred as the target, is a piece of the material to be applied over the substrates. The gas atoms become positively charged ions by losing electrons within the plasma and are then accelerated with adequate kinetic energy to hit the target and dislocate atoms or molecules from the target material. This sputtered material now consists of a vapor stream, which passes through the chamber, and strikes and sticks onto the substrate as a film or coating.
The surface of the substrate needs to be kept clean so as to obtain good film adhesion. Suitable cleaning and handling procedures must be used before placing substrates into the vacuum chamber. Moreover, it is common to incorporate in situ cleaning features like sputter etch into the sputter system as an option. Various measures may have to be taken in order to obtain the desired film properties. The sputter system design allows process engineers to adjust a number of parameters to obtain desired results for variables such as grain structure, uniformity, thickness, stress, adhesion strength, optical or electrical properties, and much more. The type of power to be employed on the cathodes must also be taken into account. DC power is ideal for conductive materials. On the other hand, RF power is also capable of sputtering non conductive materials. Pulsed DC is suitable for some techniques such as reactive sputtering.
Reactive sputtering process employs the combination of a non inert gas, such as oxygen, and an elemental target material, such as silicon. This gas chemically reacts with the sputtered atoms within the chamber, generating a new compound which serves as the coating material rather than the original pure target material.
Configuration of Thin Film Deposition Sputter Systems
It is possible to configure thin film deposition sputter systems with many different hardware or software options, which include substrate pre heat stations and sputter etch or ion source capability for in situ cleaning of substrate surfaces. Substrate bias capability, load lock stations and/or substrate handlers, confocal arrangements of cathodes, and multiple cathodes are the other options available. Moreover, accessories like residual gas analyzers and other custom automation and features are also available. Magnetron cathodes are the well known type available in many different shapes and sizes and the most recognized type of high vacuum pump is cryogenic pumps.
Thin film deposition sputtering provides the benefits of good film adhesion strength and better step or via coverage. Concurrent double sided coating can be performed with appropriate mechanical configuration.
About Semicore Equipment
Semicore is a manufacturer and worldwide supplier for the electronics, optical, solar energy, medical, automotive, military and related high technology industries.
Our high-performance production or R&D vacuum sputtering and thin film evaporation systems provide coatings on a variety of materials including plastic films, glass, ceramics, metals and hybrid substrates.
Whether you want to take advantage of our proven industrial solutions for vacuum system automation, process control and supervisory monitoring applications or need to develop some unique new application of your own design you will find Semicore’s staff and facilities to be competent, open-minded and eager to help.
This information has been sourced, reviewed and adapted from materials provided by Semicore Equipment.
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