Physical Vapour Deposition (PVD) technology means that under vacuum conditions, physical methods are used to vaporize the material source-solid or liquid surface into gaseous atoms, molecules or part of ionization into ions, and pass low-pressure gas (or plasma) ) Process, a technology of depositing a thin film with a certain special function on the surface of the substrate. The main methods of physical vapor deposition include vacuum evaporation, sputtering coating, arc plasma coating, ion coating, and molecular beam epitaxy. Up to now, physical vapor deposition technology can not only deposit metal films, alloy films, but also compounds, ceramics, semiconductors, and polymer films.
In order to create the environments for PVD process, a vacuum chamber is required. The chamber's main frame and shell is usually build by stainless steel. Vast amount of electric insulators required in the equipment as well. Most of these insulators are ceramics, e.g. boron nitride and it's composite material (check the blog here for more about boron nitride), to withstand the potential high temperature.
In the process of movement, it continuously collides with argon atoms and ionizes a large number of argon ions to bombard the target. After multiple collisions, the energy of the electrons gradually decreases, getting rid of the constraints of the magnetic lines of force, away from the target, and finally deposited on the substrate. Magnetron sputtering is to confine and extend the movement path of electrons with a magnetic field, change the direction of movement of electrons, increase the ionization rate of the working gas and effectively use the energy of electrons. The fate of electrons is not only the substrate, but also the inner wall of the vacuum chamber and the anode of the target source. But generally the substrate, the vacuum chamber and the anode are at the same potential. The interaction between the magnetic field and the electric field (E X B drift) makes the trajectory of a single electron appear a three-dimensional spiral instead of just moving in a circle on the target surface. As for the circumferential sputtering profile of the target surface, the magnetic field lines of the target source are distributed in a circumferential shape. The different distribution directions of the magnetic field lines have a great influence on film formation. In addition to magnetron sputtering that works under the E X B shift mechanism, there are also multi-arc plating target sources, ion sources, and plasma sources that all work under this principle. The difference is the direction of the electric field, the magnitude of voltage and current and other factors.
The basic principle of magnetron sputtering is to use the plasma in the Ar-O2 mixed gas under the action of an electric field and an alternating magnetic field to bombard the surface of the target by accelerated high-energy particles. After the energy exchange, the atoms on the sputtering target surface are separated from the original crystal. The grid escapes and transfers to the surface of the substrate to form a film.
Magnetron sputtering is characterized by high film forming rate, low substrate temperature, good film adhesion, and large area coating can be achieved. The technology can be divided into DC magnetron sputtering method and radio frequency magnetron sputtering method.
Magnetron sputtering (magnetron-sputtering) is a kind of "high-speed low-temperature sputtering technology" that developed rapidly in the 1970s. Magnetron sputtering forms an orthogonal electromagnetic field above the surface of the cathode target. When the secondary electrons generated by sputtering are accelerated into high-energy electrons in the cathode drop zone, they do not fly directly to the anode, but make a cycloidal motion that oscillates back and forth under the action of an orthogonal electromagnetic field. High-energy electrons constantly collide with gas molecules and transfer energy to the latter, ionizing them and turning themselves into low-energy electrons. These low-energy electrons eventually drift to the auxiliary anode near the cathode along the lines of magnetic force and are absorbed, avoiding the strong bombardment of the high-energy electrons on the electrode plate, and eliminating the damage caused by the bombardment heating and the electron irradiation of the electrode plate in the two-pole sputtering. The "low temperature" characteristics of the pole plate in magnetron sputtering. Due to the presence of an external magnetic field, the complex movement of electrons increases the ionization rate and achieves high-speed sputtering. The technical feature of magnetron sputtering is to generate a magnetic field perpendicular to the direction of the electric field in the vicinity of the cathode target surface, which is generally realized by permanent magnets.
On July 15th 2021, QSAM delivered a super large lanthanum boride sputter target to customer. This new target has 15" diameter and has to be packed in wooden crate to insure safety. So far this is the largest single tile flat LaB6 sputter target in commercial market.
A. Applied Materials Corporation
AM is the top manufacturer of semiconductors and display devices. Applied Materials Corporation was established in 1967, with annual revenue of 4.6 billion in fiscal year 2019,
B. Kurt J Lesker
KJ is a reputable supplier of vacuum equipments including PVD chamber, ion source, crucibles and sputter targets
C.QS Advanced Materials
QSAM is a company foucsing on making sputtering targets and custom materials of all kinds of shape and composition.
The industry chain of sputtering targets mainly includes metal purification, target manufacturing, sputtering coating and terminal applications. Among them, target manufacturing and sputtering coating are the key links in the entire sputtering target industry chain. According to chemical composition, sputtering targets can be divided into:
(1) Metal targets (pure metal aluminum, titanium, copper, tantalum, etc.)
(2) Alloy targets (nickel-chromium alloy, nickel-cobalt alloy, etc.)
(3) Ceramic compound targets (oxide, silicide, carbide, sulfide, etc.)
The biggest applications are various integrated circuits, very large scale integrated circuits, and semiconductor chips! These fields are closely related to the recently mentioned replacement of domestic semiconductor chips and the 5G communications industry! The field of VLSI chip manufacturing is the most high-end application of sputtering targets. It has the highest requirements for the metal purity of the sputtering target, which usually requires 99.9995% (5N5) or more. The metal purity of aluminum targets for flat panel displays and solar cells is slightly Low, it is required to reach 99.999% (5N) and 99.995% (4N5) respectively. Up to 99.999 (and the purity of general metal is also 99.8). The sputtering target is made of copper, aluminum, tantalum, titanium and other materials with a purity of 99.999%. The chip manufacturer uses advanced equipment to uniformly bombard the sputtering target onto the substrate. After a similar light and shadow fixing technology, a variety of Conductive lines. It is precisely because the integrated circuit of 1 square centimeter is equipped with ultra-fine metal wires with a length of tens of thousands of meters that we have smart electronic products that are getting smaller and smaller and more powerful today. At present, ultra-high-purity metal materials and sputtering targets are used in VLSI and chip manufacturing in the world.