Magnetron sputtering targets

1) Magnetron sputtering principle.
In the sputtered target pole (cathode) and the anode between the addition of an orthogonal magnetic and electric field, in a high vacuum chamber filled with the required inert gas (usually Ar gas), permanent magnets in the target material surface to form a magnetic field of 250 ~ 350 gauss, with the high voltage electric field to form an orthogonal electromagnetic field. Under the action of the electric field, the Ar gas is ionised into positive ions and electrons, the target is added with a certain negative high voltage, the electrons from the target are subject to the action of the magnetic field and the ionisation of the working gas increases, a high density plasma is formed near the cathode, the Ar ions are accelerated under the action of the Lorentz force and fly towards the target surface, bombarding the target surface with a very high speed, so that the atoms sputtered out of the target follow the principle of momentum conversion with a high The atoms sputtered on the target follow the kinetic energy conversion principle and fly off the target surface towards the substrate to deposit a film. Magnetron sputtering is generally divided into two types: DC sputtering and RF sputtering, where the principle of DC sputtering equipment is simple and the rate is fast when sputtering metals. RF sputtering, on the other hand, can be used in a wider range of applications and can sputter non-conductive materials in addition to electrically conductive materials, as well as reactive sputtering for the preparation of compound materials such as oxides, nitrides and carbides. If the frequency of RF is increased it becomes microwave plasma sputtering, today, commonly used are electron cyclotron resonance (ECR) type microwave plasma sputtering.
2) Types of magnetron sputtering targets.
Metal sputtering coating target, alloy sputtering coating target, ceramic sputtering coating target, boride ceramic sputtering target, carbide ceramic sputtering target, fluoride ceramic sputtering target, nitride ceramic sputtering target, oxide ceramic target, selenide ceramic sputtering target, silicide ceramic sputtering target, sulfide ceramic sputtering target, telluride ceramic sputtering target, other ceramic targets, chromium-doped a silicon oxide ceramic targets (Cr-SiO), indium phosphide targets (InP), lead arsenide targets (PbAs), indium arsenide targets (InAs). [2]
Application Areas Editor Voice
As we all know, the technology development trend of target materials is closely related to the development trend of thin film technology in the downstream application industry, and as the application industry improves the technology in thin film products or components, the target material technology should also change. For example, Ic manufacturers. In recent times dedicated to the development of low resistivity copper wiring, is expected to substantially replace the original aluminum film in the next few years, so that the development of copper targets and their required barrier layer target material will be urgent. In addition, in recent years, the flat panel display (FPD) significantly replaced the original cathode ray tube (CRT) based computer monitor and television market. Will also significantly increase the technology and market demand for ITO targets. In addition, in the storage technology. High-density, high-capacity hard disk, high-density rewritable optical disc demand continues to increase. All of these have led to changes in the application industry demand for target materials. In the following we will introduce the main application areas of target materials, and the trend of target material development in these areas.
Microelectronics
The semiconductor industry has the most demanding quality requirements for target sputtering films of any application industry. Today, silicon wafers of up to 12 inches (300 epitodes) are manufactured. while the width of the interconnects is decreasing. The requirements of silicon wafer manufacturers for large sizes, high purity, low segregation and fine grains require that the targets manufactured have a better microstructure. The crystalline particle diameter and uniformity of the target has been identified as a key factor affecting the deposition rate of the film. In addition, the purity of the film is highly dependent on the purity of the target. In the past, a 99.995% (4N5) pure copper target might be able to meet the needs of semiconductor manufacturers for the 0.35pm process, but it cannot meet the requirements of today’s 0.25um process, while the 0.18um} art or even 0.13m process for the unmetered will require a target purity of 5 or even 6N or more. Copper compared with aluminium, copper has a higher resistance to electromigration and lower resistivity to meet! The conductor process requires sub-micron wiring below 0.25um but brings with it other problems: the adhesion strength of copper to organic dielectric materials is low. And easy to react, resulting in the use of the chip copper interconnection line is corroded and broken. In order to solve these problems, the need to set up a barrier layer between the copper and dielectric layer. Blocking layer materials are generally used high melting point, high resistivity of the metal and its compounds, so the thickness of the blocking layer is less than 50nm, and copper and dielectric material adhesion performance is good. Copper interconnection and aluminium interconnection of the blocking layer material is different. New target materials need to be developed. Copper interconnection of the blocking layer with target materials including Ta, W, TaSi, WSi, etc.. But Ta, W are refractory metals. Production is relatively difficult, now is studying molybdenum, chromium and other Taiwan gold as alternative materials.
For displays
Flat panel displays (FPD) have had a significant impact on the computer monitor and television market over the years, mainly in the form of cathode ray tubes (CRT), which will also drive the technology and market demand for ITO targets. There are two types of iTO targets available today. One is the use of nano-state indium oxide and tin oxide powder mixed and sintered, one is the use of indium tin alloy target. Indium-tin alloy targets can be used for ITO thin films by DC reactive sputtering, but the target surface will oxidise and affect the sputtering rate, and it is not easy to obtain large size of Taiwan gold targets. Nowadays, the first method is generally adopted to produce ITO targets, using L}IRF reactive sputtering coating. It has a fast deposition speed. And can accurately control the thickness of the film, high conductivity, good consistency of the film, and strong adhesion to the substrate, etc. l. But the target material production difficulties, which is because indium oxide and tin oxide is not easy to sinter together. ZrO2, Bi2O3 and CeO are generally used as sintering additives and are able to obtain targets with a density of 93% to 98% of the theoretical value. The performance of ITO films formed in this way is highly dependent on the additives. Japanese scientists use Bizo as an additive, Bi2O3 melts at 820Cr and has volatilised beyond the sintering temperature of l500°C. This enables a relatively pure ITO target to be obtained under liquid phase sintering conditions. Moreover, the oxide raw material required does not necessarily have to be nanoparticles, which simplifies the preliminary process. In 2000, the National Development Planning Commission, the Ministry of Science and Technology Ministry of Science and Technology in the “current priority development of information industry key areas guide”, ITO large target material is also included.
For storage
In storage technology, the development of high-density, high-capacity hard disk requires a large number of giant magnetoresistive film materials, and CoF~Cu multilayer composite film is a widely used giant magnetoresistive film structure today. The TbFeCo alloy target material required for magnetic discs is still being further developed, and the magnetic discs made from it have high storage capacity, long life and can be repeatedly erased without contact. The magnetic discs developed today have a layer composite film structure of TbFeCo/Ta and TbFeCo/Al. The Kerr rotation angle of the TbFeCo/AI structure reaches 58, while TbFeCofFa can be close to 0.8. It has been found that the low magnetic permeability of the target material high AC partial discharge voltage l resists electrical strength.
Germanium antimony telluride based phase change memories (PCM) have shown significant commercial potential as an alternative memory technology for NOR type flash and part of the DRAM market, however, one of the challenges on the road to faster scaling is the lack of fully hermetic cells that can be produced to further reduce the reset current. Lower reset currents can reduce memory power consumption, extend battery life and increase data bandwidth, all important features for today’s data-centric, highly portable consumer