News & Articles

Learn about vacuum sputtering and thin film evaporation technologies.

What is HIPIMS? High Power Impulse Magnetron Sputtering

High Voltage Spark

High Power Impulse Magnetron Sputtering or HIPIMS is a relatively recent advance in sputtering technology used for the physical vapor deposition of thin film coatings based upon Magnetron Sputtering with a high voltage pulsed power source. HIPIMS utilizes a very high voltage, short duration burst of energy focused on the target coating material to generate a high density plasma that results in a high degree of ionization of the coating material in the plasma.

By pulsing the target coating material with bursts of high voltage energy – with a length of ~100 µs on the order of kW·cm-2 but with a relatively short duration or “Duty time” of less than 10% – allows for a large fraction of the sputtered target material to be ionized in the plasma cloud without overheating the target and other components of the system. The target has a chance to cool during the predominant “Off duty” time which results in a low average cathode power of 1–10 kW which helps maintain process stability. …

What is RF Sputtering?

magnetron sputtering source

RF or Radio Frequency Sputtering is the technique involved in alternating the electrical potential of the current in the vacuum environment at radio frequencies to avoid a charge building up on certain types of sputtering target materials, which over time can result in arcing into the plasma that spews droplets creating quality control issues on the thin films – and can even lead to the complete cessation of the sputtering of atoms terminating the process.

Traditional DC Sputtering is a cost effective way of applying metal target coatings that are electrical conductors like gold. However, DC Sputtering is limited when it comes to dielectric target materials – coatings which are non-conducting insulating materials that can take on a polarized charge. Examples of common dielectric coating materials used in the semiconductor industry include Aluminum Oxide, Silicon Oxide and Tantalum Oxide. …

What is E-Beam Evaporation?

Electron-Beam Evaporation Equipment

E-Beam or Electron Beam Evaporation is a form of Physical Vapor Deposition in which the target material to be used as a coating is bombarded with an electron beam from a charged tungsten filament to evaporate and convert it to a gaseous state for deposition on the material to be coated. Taking place in a high vacuum chamber, these atoms or molecules in a vapor phase then precipitate and form a thin film coating on the substrate.

E-Beam Evaporation, which is a Thermal Evaporation process, and Sputtering are the two most common types of Physical Vapor Deposition or PVD. Of these two processes, The E-Beam Deposition technique has several clear advantages for many types of applications. …

What Is Thin Film Deposition?

What is Thin Film DepositionThin Film Deposition is the technology of applying a very thin film of material – between a few nanometers to about 100 micrometers, or the thickness of a few atoms – onto a “substrate” surface to be coated, or onto a previously deposited coating to form layers. Thin Film Deposition manufacturing processes are at the heart of today’s semiconductor industry, solar panels, CDs, disk drives, and optical devices industries.

Thin Film Deposition is usually divided into two broad categories – Chemical Deposition and Physical Vapor Deposition Coating Systems.

Chemical Deposition is when a volatile fluid precursor produces a chemical change on a surface leaving a chemically deposited coating.  One example is Chemical Vapor Deposition or CVD used to produce the highest-purity, highest-performance solid materials in the semiconductor industry today.

Physical Vapor Deposition refers to a wide range of technologies where a material is released from a source and deposited on a substrate using mechanical, electromechanical or thermodynamic processes. The two most common techniques of Physical Vapor Deposition or PVD are Thermal Evaporation and Sputtering. …

Thin Film Deposition By Sputtering: Essential Basics

abstract sputtering glow

There are several methods of Thin Film Deposition which is a vacuum technology for applying coatings of pure materials to the surface of various objects. The coatings are usually in the thickness range of angstroms to microns and can be a single material, or multiple materials in a layered structure.

The object to be coated is referred to as the substrate, and can be any of a wide variety of things such as: semiconductor wafers, solar cells, optical components, or many other possibilities. The materials to be applied can be pure atomic elements including both metals and non metals, or can be molecules such as oxides and nitrides. …

What is Thin Film Deposition By Thermal Evaporation?

Thin Film Semiconductor Wafers

One of the common methods of Physical Vapor Deposition (PVD) is Thermal Evaporation. This is a form of Thin Film Deposition, which is a vacuum technology for applying coatings of pure materials to the surface of various objects. The coatings, also called films, are usually in the thickness range of angstroms to microns and can be a single material, or can be multiple materials in a layered structure.

Diagram of Thermal Evaporation Process

Diagram of
Thermal Evaporation Process

The materials to be applied with Thermal Evaporation techniques can be pure atomic elements including both metals and non metals, or can be molecules such as oxides and nitrides. The object to be coated is referred to as the substrate, and can be any of a wide variety of things such as: semiconductor wafers, solar cells, optical components, or many other possibilities.

Thermal Evaporation involves heating a solid material inside a high vacuum chamber, taking it to a temperature which produces some vapor pressure. Inside the vacuum, even a relatively low vapor pressure is sufficient to raise a vapor cloud inside the chamber. This evaporated material now constitutes a vapor stream, which traverses the chamber and hits the substrate, sticking to it as a coating or film. …

Features of In-Line Sputtering Systems

in-line sputtering system

An “In-Line” PVD Sputtering System is one in which substrates pass linearly beneath one or more Sputter cathodes to acquire their Thin Film coating. Normally the substrates are loaded onto a carrier or pallet in order to facilitate this motion, and some smaller systems handle just one pallet per batch run. Larger systems may have the capability of handling multiple pallets through the use of end station pallet handlers that send and receive one pallet after another in a continuing convoy passing through the transport subsystem, the tip of each following behind the tail of the prior one.

The most common, and least complex, configuration is to have the pallets and cathodes horizontal with cathodes on top and substrates on the bottom in a sputter down orientation. In this mode, gravity is usually the only thing holding the substrates onto the pallets, and also the only thing holding the pallets onto the transport mechanism, which can just be chains running along side rails through the vacuum chamber. …

What is Patterned Thin Film Deposition For Lift Off?

lift offThin Film Coatings are sometimes applied to entire surfaces of substrates, “wall to wall” so to speak, in a continuous unbroken film. But many times the final form of whatever particular material is being applied is patterned so that it is coated in certain specific areas and bare in others.

There are two principal ways to achieve this effect:

1) Subtractive, or Etch Back process – the entire surface is coated, and then select portions are removed, leaving the desired pattern. The pattern generating step normally involves some form of physical masking agent and then an appropriate type of etching to remove what should be removed and not damage anything else.

2) Additive, or Lift Off process – the pattern generating step, which again will normally involve some sort of physical masking agent, comes first. This is followed by the coating process, which is similar to using a stencil. Only the desired pattern gets applied through the openings in the deposition mask onto the actual substrate. The excess ends up on top of the mask and is removed when the deposition mask is lifted off. This type of Thin Film Deposition Lift Off process will be the subject of this article. …

Advanced Thin Film Deposition Control by Quartz Crystal Monitor

wafer patternedPhysical Vapor Deposition (PVD) is a common class of techniques for applying very pure coatings usually in the thickness of angstroms to microns onto substrates, and includes Thermal Evaporation from a heated source. This paper discusses principles of Advanced Thin Film Deposition thickness and rate control by use of quartz crystal monitoring. In particular it will go beyond the basics into topics including co-deposition and multi crystal systems for PVD by Thermal Evaporation.

Key to understanding the basis of how quartz crystals are used to measure and control the deposition rate is that as the thin film is being deposited on the crystal in real time in the vacuum chamber, the crystal’s oscillation frequency drops as the crystal’s mass increases from the material being deposited on it. To complete the monitoring system, an electronic instrument continuously reads the frequency converting that frequency data to Thin Film Deposition thickness data, both the instantaneous rate and cumulated thickness. …

What is Reactive Sputtering?

Reactive Sputtering Equipment

Sputtering is a common technique for Physical Vapor Deposition (PVD), one of the methods of producing Thin Film Coatings. Standard Sputtering uses a target of whatever pure material is desired, and an inert gas, usually argon. If the material is a single pure chemical element, the atoms simply come off the target in that form and deposit in that form.

However, it is also possible to use a non inert gas such as oxygen or nitrogen either in place of, or (more commonly) in addition to the inert gas (argon). When this is done, the ionized non inert gas can react chemically with the target material vapor cloud and produce a molecular compound which then becomes the deposited film. For example, a silicon target reactively sputtered with oxygen gas can produce a silicon oxide film, or with nitrogen gas can produce a silicon nitride film. …