Category: knowledge

Introduction to the Process and Steps of Evaporation Coating

The basic process flow for evaporation coating is:

Preparation before coating→ vacuum→ ion bombardment→ baking→ premelting→ evaporation→ removing parts→ film surface treatment→ finished product

1. Preparation before coating

The process includes vacuum chamber coating part cleaning, evaporation source making and cleaning, installation of evaporation source and evaporation materials.

The amount of bonding between the film layer and the surface of substrate is an important indicator of product quality. It is determined by many factors, and the surface treatment before coating is one of the most basic factors. If there is grease on the surface of the coating part, adsorbing water, dust, etc., it will reduce the bonding force of the film layer and affect the surface roughness. Cleaning is generally done by several methods: chemical degreasing, electrostatic dedusting and primer application.

According to the requirements of the product and the material of the coating parts, selecting the appropriate evaporation material is the basic condition for obtaining a high-quality film layer. For different evaporation materials, the corresponding evaporation source and the evaporation method should be selected.

The basic principle of selecting metal evaporation materials is: good thermal stability and chemical stability, high mechanical strength, low internal stress, and certain toughness, good bonding with primer, high reflectivity, and small gas release in vacuum; the material source is wide, the price is low, and it has a corresponding evaporation source.

2. Vacuum step

Open the cooling water valve, adjust to the required water pressure, turn on the main power supply, close the atmospheric valve leading to the vacuum chamber, close the pipeline valve, start the mechanical pump power supply, and open the pre-vacuum valve; At this time, the vacuum chamber is evacuated using a diffusion pump or a mechanical pump, and baking, pre-melting, and evaporation are performed when the degree of vacuum reaches a certain value.

3. Ion bombardment

In the glow discharge, the ion bombardment electrons obtain a high speed, and the negative charge is rapidly generated around the substrate due to the large mobility of the electron. Under the action of the negative charge attraction, the positive ion bombards the surface of the coating part, and the substrate. There is energy exchange on the surface, and a chemical reaction occurs between the adsorption layer of the coating member and the active gas to achieve the effect of cleaning the surface.
The conditions of ion bombardment are that the residual gas pressure is stable at 0.13~13Pa, the voltage is 1.5~10kV, and the time is 5~60min.

4. Baking

It can accelerate the rapid escape of the gas adsorbed by the coating parts or the clamp, which is beneficial to improve the vacuum degree and the film bonding force. When baking, it should be noted that the non-metal baking temperature is lower than the hot deformation temperature of the coating part by 20~30 °C, and the metal baking is generally not more than 200 °C.

5. Pre-melting

This step can remove the low melting point impurities in the evaporation material and the gas adsorbed in the evaporation source and the evaporation material, which is favorable for the smooth progress of evaporation. The pre-melted vacuum is generally 6.6 x 10-3 Pa. For materials with high hygroscopicity, it should be pre-melted repeatedly. The overall requirement is that the vacuum does not drop as the evaporating material warms to the evaporating temperature.

6. Evaporation

Evaporation technology has a great impact on film quality. There are different requirements for general metals, special metals and compound evaporating pellets. For example, some metal particles need to be evaporated quickly, while others are not suitable. The heating method and the shape of the evaporation source should also be different depending on the evaporation material.

Please visit https://www.sputtertargets.net/by-evaporation-materials.html for more information.

Sputter Coating Advantages vs. Disadvantages

Sputter coating is the core thin film deposition process in the semiconductor, disk drive, CD and optics industries today.

When a suitable gas (usually argon) and a target material (usually metals) are used to form a glow discharge between the cathode and the anode, the sputtering target is bombarded to cause the atoms to be ejected from the target material——the process is referred to as “sputtering”; the atoms of the sputtering target will be deposited on a substrate, such as a silicon wafer, solar panel or optical device, and this process is known as sputter deposition.

Sputter deposition, as a relatively common physical vapor deposition (PVD) method, has its advantages, such as a wide range of deposition materials and high coating quality.

The table below details the advantages and disadvantages of sputter coating. It is provided by Stanford Advanced Materials and is for informational purposes only.

Advantages Disadvantages
(1) Able to deposit a wide variety of metals, insulators, alloys and composites.

(2) Replication of target composition in the deposited films.

(3) Capable of in-situ cleaning prior to film deposition by reversing the potential on the electrodes .

(4) Better film quality and step coverage than evaporation.

(5) This is partly because adatoms are more  energetic, and film is ‘densified’ by in-situ ion bombardment, and it is easier to heat up to high T than evaporation that is in vacuum.

(6) More reproducible deposition control – same deposition rate for same process parameters (not true for evaporation), so easy film thickness control via time.

(7) Can use large area targets for uniform thickness over large substrates.

(8) Sufficient target material for many depositions.

(9) No x-ray damage.

 (1) Substrate damage due to ion bombardment or UV generated by plasma.

(2) Higher pressures 1 –100 mtorr ( < 10-5 torr in evaporation), more contaminations unless using ultra clean gasses and ultra clean targets.

(3) Deposition rate of some materials quite low.

(4) Some materials (e.g., organics) degrade due to ionic bombardment.

(5) Most of the energy incident on the target becomes heat, which must be removed.

For more information, please visit https://www.sputtertargets.net/sputtering-target-materials.html.

An Overview of Copper Sputtering Target

Copper sputtering targets, as part of vacuum coating materials, are widely applied in tool coating, optics coating, solar coating, and etc.  Copper targets can be put together with metallic copper because they are essentially the same–composed by Cu atoms.

Development of Copper

Copper is one of the earliest metals discovered by mankind and the first metal that humans began to use. Copper beads made of natural copper excavated by archaeologists in northern Iraq are supposed to have been more than 10,000 years old. Methods for refining copper from its ores were discovered around 5000BC and a 1000 or so years later it was being used in pottery in North Africa.

In modern industry, copper was widely used in the power and electronics industries. By the 1960s, copper used in these two industries accounted for 28%. By 1997, these two industries were still the main areas of copper consumption, accounting for Than 25%. Later, copper was widely used in electrical, light industry, machinery manufacturing, construction industry, transportation, and other fields. As far as America is concerned, copper is second only to aluminum in the consumption of non-ferrous materials. Copper has excellent performance and is easy to recycle and recycle. At present, there are already relatively complete recycled copper recycling systems in developed countries. For example, the output of recycled copper in the United States accounts for 60% of the total output, and Germany accounts for 80%.

Copper Sputtering Target Property

Copper is a chemical metal element with the symbol Cu. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement.

Material Type Copper
Symbol Cu
Color/Appearance Copper, Metallic
Melting Point 1,083 ℃
Density 8.96 g/cm3
Sputter DC
Type of Bond Indium, Elastomer
Comments Adhesion poor. Use interlayer (Cr). Evaporates using any source material.

From Metal Copper to Copper Sputter Target

The copper sputtering target is a kind of copper product made of the metal copper, and it is used in the sputter coating to produce copper thin film. Simply speaking, there are two methods to make copper sputtering target from metal copper.

Casting: melt the raw material of a certain distribution ratio, pour the alloy solution into a mold to form an ingot, and finally machine it to become a sputtering target. The method is smelted and cast in a vacuum.

Powder metallurgy: melt the raw material of a certain distribution ratio, cast it into an ingot and then pulverize it, isostatically press the powder, and then sintering it at a high temperature to finally form a target.

 

Powder metallurgy process
Powder metallurgy process

Basic Requirement of Copper SputterTarget

In general, when measuring whether the sputtering target meets the primary requirements, one would consider the following indicators:

Purity: Purity has a great influence on the performance of the film produced by sputter coating. Taking copper target as an example, the higher the purity is, the better the corrosion resistance and electrical and optical properties of the sputtered film are.

Impurity content: The impurities in the solid of the target material and the oxygen and water vapor in the stoma are the main pollution sources of the deposition film. Targets for different applications have different requirements of their impurity contents.

Density: The density of the target not only affects the sputtering rate but also affects the electrical and optical properties of the film. Thus, in order to reduce pores in the solids of the target and improve the properties of the sputtered film, the target is usually required to have a higher density.

Grain size and grain size distribution: For the same target, the sputtering rate of the fine-grained target is faster than that of the coarse-grained target; and the thickness of the target sputter-deposited film with a smaller difference in grain size (distributed uniformly) is more uniform.

Information provided by SAM Sputter Targets.

Introduction to Two Important Vacuum Coating Methods

In today’s electronics industry, many electronic components are manufactured using a vacuum coating process. Vacuum coating has become an indispensable technology for the manufacture of electronic components. The current vacuum coating technology is to evaporate and sputter a metal or alloy in a vacuum to deposit it on a substrate. Vacuum evaporation and magnetron sputtering coating are two main vacuum coating technologies.

Vacuum evaporation

History

In 1857, Michael Faraday first proposed the basic principle of vacuum evaporation. Later, in the 1930s, the oil diffusion vacuum pump was put into practical use, and it was mainly used to make the lens anti-reflection film. During the Second World War, the demand for materials from other optical machines increased, and vacuum evaporation also developed rapidly.

Principle

In a vacuum state, the evaporation pellets in the evaporation vessel is heated to cause atoms or molecules to escape and deposit on the surface of the evaporation material to form a solid film. Depending on the type of vapor deposition material or substrate, it can be classified into heating methods such as resistance heating, electron beam, high-cycle induction, and laser. The vapor deposition materials include metal evaporation materials such as aluminum, lead, gold, silver, platinum, and nickel, and materials capable of producing optical properties, and oxides and fluorides such as SiO2, TiO2, ZrO2, and MgF2 are mainly used. In addition to metal, vapor deposition can be used for resin and glass, and in recent years, continuous paper has also become vapor-depositable.

Advantages

The device is simple and easy to operate; the film formation rate is fast and the efficiency is high.

Disadvantages

The thickness uniformity of the film is not easy to control, the evaporation container has hidden dangers, the process repeatability is not good, and the adhesion is not high.

Magnetron sputtering coating

History

As a very effective thin film deposition method, magnetron sputtering technology has been widely and successfully applied in many fields, especially in the fields of microelectronics, optical films and material surface treatment, for thin film deposition and surface coating preparation. In 1852, Grove first described the physical phenomenon of sputtering. In the 1940s, sputtering technology began to be applied and developed as a deposition coating method. With the rapid rise of the semiconductor industry in the 1960s, this technology was widely used and widely used in the integrated circuit production process for depositing metal electrode layers of transistors in integrated circuits. The emergence and development of magnetron sputtering technology, and the use of reflective layers for CD production in the 1980s, the field of application of magnetron sputtering technology has been greatly expanded, and gradually become a common means of manufacturing many products, and in the last ten years, a series of new sputtering techniques were developed.

Principle

Electrons accelerate to the substrate under the action of an electric field. In this process, electrons collide with argon atoms to ionize a large amount of argon ions and electrons. Under the action of an electric field, argon ions accelerate the bombardment of the sputtering target, and sputter a large number of target atoms, and the target atoms are deposited on the surface of the substrate to form a film.

Advantages

The process repeatability is good, the film has high purity, uniform film thickness and good adhesion.

Disadvantages

The structure of the device is complicated, and once the sputtering target penetrates, the entire target is scrapped, so the utilization rate of the target is low. Using rotatory sputtering target can increase the utilization of the target.

Please visit https://www.sputtertargets.net/ for more information.

How to Correctly Use the Sputter Coater Target (Precautions During The Sputtering Process)

Sputter coater targets have high requirements during use, requiring not only purity, size, and even grain size uniformity. These high requirements make us pay more attention when using sputtering targets. Let’s take a look at the five points of use of the sputtering coater target during use.

  1. Sputter preparation

It is very important to keep the vacuum chamber and the sputtering system clean. Any residue formed by lubricating oil and dust, as well as pre-coating, will accumulate moisture and other contaminants, directly increasing the possibility of film failure. Apart from it, the unclean sputtering chambers, sputter guns, and sputtering targets will also cause system short circuits, target arcing and rough surface formation.

In order to maintain the composition characteristics of the coating, the sputtering gas (argon or oxygen) must be cleaned and dried. After the substrate is placed in the sputtering chamber, the air needs to be extracted to achieve the vacuum level required by the process.

  1. Target cleaning

The purpose of target cleaning is the same as the first point in order to remove dust or dirt that may be present on the surface of the target and keep it clean.

  1. Target installation

The most important precaution during target installation is to ensure a good thermal connection between the target and the stabilizing wall of the sputter gun. If the warp of the cooling stave or backing plate is severe, it may cause cracking or bending of the target during installation. In this way, the thermal conductivity of the backing plate to the target is greatly affected, resulting in the inability to dissipate heat during the sputtering process, which eventually causes the target to crack or off.

  1. Short circuit and seal check

After the target is installed in the sputtering machine, it is necessary to inspect the circuit condition and seal of the cathode. It is recommended to judge whether there is a short circuit in the cathode by observing the way the resistance meter shakes. After determining that there is no short circuit in the cathode, water can be passed to the cathode to determine if there is water leakage.

  1. Target pre-sputtering

It is recommended to use pure argon for target pre-sputtering, which can help clean the surface of the target. When the sputter coating target is pre-sputtered, it is recommended to increase the sputtering power slowly. The power-increasing rate of the ceramic target is recommended to be 1.5 Wh/cm2, and the pre-sputtering speed of the metal sputter coater target materials can be 1.8 Wh/cm2 with a reasonable power increase rate compared to the ceramic target block.

For more information, please visit https://www.sputtertargets.net/.

Indium: Stable Demand in Thin Film Solar Industry

With the full arrival of the mobile energy era, the thin film solar industry grows explosively. Thin-film solar chips are light, thin, and flexible. They can be embedded in various types of carriers like Intel chips, from urban skyscrapers to neighborhood roofs, or parasols on the street, and cars running on the road. They have turned traditional products into “power generation bodies”, enabling energy sharing and free use.

Indium

Indium is one of the basic raw materials for the manufacture of thin film solar cells. Indium, atomic number 49, was discovered in 1863 by the German chemist H. Richter in zinc concentrate. Indium is silvery white and has a light blue color. The texture is very soft and can be scored with nails. In nature, indium minerals are dispersed in trace amounts in other minerals. The distribution of indium in the earth’s crust is relatively small, 1/8 of gold and 1/50 of silver. So far, no single or indium-based natural indium deposit has been found. Therefore, indium resources, in people’s impression, are scarce and difficult to mine, so that there is concern about whether there will be shortages and unstable prices of the precious metal.

Luckily, it is optimistic that the industry has said that with the improvement of mining technology, drilling technology, purification technology and recycling technology, more and more indium resources can be used. Therefore, even if the output of copper indium gallium selenide (CIGS) increases explosively in the next few years, it is difficult to affect the supply and demand of indium.

CIGS solar cell

CIGS solar cellIn the future, the copper indium gallium selenide film industry will enter a period of low-cost and high-speed development, and the thin-film solar market will be fully opened. As the photovoltaic industry continues to evolve, reducing power generation costs is a continuing goal. In this context, reducing the amount of precious indium through technical routes is a cost-reduction method that many companies are actively exploring.

At present, some companies have developed a more reliable solution to reduce the amount of indium used in copper-indium-gallium-selenide modules: developing new plasma-spray target technology, reducing the loss in sputtering target coating, reclaiming indium on residual targets, and etc. In addition, by appropriately increasing the composition of gallium or thinning the battery film layer in the copper indium gallium selenide battery, the amount of indium can also be effectively reduced.

The industry produces metal indium by purifying waste zinc and waste tin, and the recovery rate is about 60-70%. From this calculation, based on the proven reserves, the increase in recoverable amount and the indium recovery rate, the currently available indium is about 15,000 tons to 18,000 tons. If all of these indiums are used to produce copper indium gallium selenide batteries, it can produce 1,800 GW, and even if only one-tenth of the amount is used, it can produce 180 GW. In conclusion, in terms of current copper indium gallium selenide production capacity, indium resources are still very rich.

For more information about thin film coating, please visit https://www.sputtertargets.net/.

 

Reliable Sputtering Target Manufacturer: Stanford Advanced Materials

Part of SAM

Stanford Advanced Materials (SAM) is a global supplier of a series of pure metals, alloys, ceramics and minerals such as oxides, chlorides, sulfides, oxysalts, etc. SAM Sputter Targets is a division of Stanford Advanced Materials, which specializes in manufacturing vacuum coating materials such as sputtering targets and evaporating pellets.

History of SAM

Stanford Advanced Materials was founded in 1994 and now has a history of 25 years.

SAM initially began supplying high-quality rare earth products to assist our customers in research and development (R&D). To meet the growing demand for rare earth products and other materials, SAM now offers sputtering materials not only for our R&D customers but also for manufacturers in the ceramics, metallurgical and electronics industries.

SAM supplies technology-grade materials to the industry and provides research institutions with high-purity chemicals (up to 99.99999%).

Products of SAM

SAM Sputter Targets is your reliable sputtering target manufacturer. SAM has long been committed to providing customers with high quality and reliable sputtering targets at very competitive prices.

Because we understand the importance of reliable and consistent materials to our customers’ R&D and production needs, we have established a strong relationship with our manufacturers.

By regularly visiting our manufacturers and talking to their management, production and quality control engineers and workers on the production line about the quality we seek, we have created truly effective partnerships. These valuable friendships built over the years have enabled us to deliver consistently high quality products to our global customers.

SAM’s motto is “We not only provide products, we also provide satisfactory service.” We believe that you will find SAM one of your favorite sputtering target suppliers.

What SAM Sells:

Alloy Sputtering Targets

Pure Metal Sputtering Targets

Oxide Ceramic Sputtering Targets

Planar Sputtering Targets

Rotatory Sputtering Targets

Click to see our full Product Categories.

For more information, you can contact us by email at target@samaterials.com or by calling (949) 407-8904. You can also visit our website at www.sputtertargets.net for information about our products, services, pricing and news.

Introduction to the Use and Application of Chromium

Chromium is a hard metal that is resistant to corrosion. It is widely used in metallurgy, chemical, cast iron, fire-resistant, and high-end technology. The specific application ratio is shown in the following figure:

specific application ratio of Chromium

Chromium in the Metallurgical Industry

Chromium is a hard metal, and is often incorporated into steel to make hard and corrosion-resistant alloys. Those alloys are mainly used to refine stainless steel, heat-resistant steel and various electric heating materials. When stainless steel encounters corrosive substances, its surface will form a fine and solid chrome oxide film, which protects the internal metal from corrosion. Some stainless steel can maintain its excellent performance even at high temperature of 800 °C. Chrome steel is a good material for manufacturing machinery, tanks and armored vehicles.

Chromium tank

Chromium in the Chemical Industry

Chromium salt is one of the main varieties of inorganic salts and is the main raw material in the chemical industry. It is widely used in daily life, including electroplating, tanning, printing and dyeing, medicine, fuel, catalyst, oxidant, match and metal corrosion inhibitor.

At the same time, metallic chromium has been listed as one of the most important coating metals–chromium sputtering targets for sputter deposition and chromium evaporation materials for evaporation coating. In most cases, the chrome layer is specifically used as the outermost coating for the parts. When chrome is applied, the thinner the chrome layer, the closer it is to the surface of the metal. The chrome layer on the inner walls of some is only five thousandths of a millimeter thick, but after firing thousands of rounds and bullets, the chrome layer still exists. If the surface is not chrome-plated, the service life of most parts will be greatly shortened due to wear and corrosion, and must be replaced or repaired frequently. Therefore, chrome plating is widely used in many industrial manufacturing.

Chromium for Refractory and Cast Iron

Chromite has a high melting point of 1900 °C – 2050 °C, and it can maintain the volume at high temperature and does not react with any slag, so it is used as a lining for refractory materials, steelmaking furnaces and non-ferrous metal smelting furnaces.

chrome brick
Chrome brick

Chromite can be used to make chrome bricks, chrome-magnesia bricks and other special refractory materials. In addition, chromium is also used in cast iron, such as chromium cast ductile iron, which has high strength, high elongation, high impact value and low hardness.

For more information, please visit https://www.sputtertargets.net/.

Physical Vapor Deposition: Sputter Coating & Evaporation

Physical vapor deposition processes use vacuum technology to create a sub-atmospheric pressure environment and an atomic or molecular condensable vapor source (from a solid or liquid surface) to deposit thin films and coatings. Sputtering deposition and vacuum evaporation are among the more well known.

physical vapor deposition sputtering evaporation

Sputtering deposition

The sputtering deposition is an etching process that alters the physical properties of a surface. In this process, a gas plasma discharge is set up between two electrodes: a cathode plating material (the sputter coater targets) and an anode material (the substrate). The film made by sputter coating are thin, ranging from 0.00005 – 0.01 mm. Chromium, titanium, aluminum, copper, molybdenum, tungsten, gold, and silver are typical sputter coating targets.

Sputter coated films are used routinely in decorative applications such as watchbands, eyeglasses, and jewelry. Also, the electronics industry relies on heavily sputtered coatings and films, such as thin film wiring on chips and recording heads as well as magnetic and magneto-optic recording media. Companies also use sputter deposition to produce reflective films for large pieces of architectural glass used in the automotive industry. Compared to other deposition processes, sputter deposition is relatively inexpensive.

vacuum coating

Vacuum Evaporation

The vacuum evaporation is a process of reducing the wastewater volume through a method that consists of concentrating a solution by eliminating the solvent by boiling. In this case, it is performed at a pressure lower than atmospheric pressure. Thus, the boiling temperature is much lower than that at atmospheric pressure, thereby resulting in notable energy savings. The basic components of this process consist of: evaporation pellets,  heat-exchanger, vacuum, vapor separator, and condenser.

Vacuum evaporation is used in the semiconductor, microelectronics, and optical industries and in this context is a process of depositing thin films of material onto surfaces. High-purity films can be obtained from a source evaporation material with high purity. The source of the material that is going to be vaporized onto the substrate can be a solid in any shape or form (usually pellets). The versatility of this method trumps other deposition processes. Also, when the deposition is not desired, masks are utilized to define the areas on the substrate for control purposes.

Information from Stanford Advanced Materials. Please visit https://www.sputtertargets.net/ for more information.

Smelting Technology of Metal Titanium and Titanium Alloy

In the industrial production of titainum and titanium alloys, the most commonly used techniques are vacuum arc remelting (VAR) and cold hearth melting.

Vacuum Arc Remelting

VAR technology can refine the ingot structure in titanium alloy smelting and improve the purity of the product. The main developments of this technology in recent years are as follows:

  • Fully-automatic VAR re-dissolution process

Advanced computer technologies are applied to VAR processes. For example, automated electronic control box data collection systems can establish excellent smelting modes for specific ingots and alloys. In addition, it can analyze the problems in the smelting process and improve the metal yield.

  • Ingot size enlargement

Large VAR furnaces can smelt titanium ingots with a mass of 30t. At present, the tonnage of vacuum self-consumption arc furnaces for molten titanium is mostly 8-15t.

  • Different power supply methods

The power supply mode adopts a coaxial power supply mode, which can cancel the magnetic field and prevent segregation.

  • Development of numerical simulation technology

Domestic and foreign scholars have made some progress in using the numerical simulation method to study the VAR process. The distribution law of the ingot temperature field has been successfully explored and a model for predicting the solidification microstructure, ingot composition and defect distribution has been established.

Cold hearth Melting

Cold hearth melting uses a plasma (Plasma Arc) or an electron beam (Electron Beam) as a heat source, and can be divided into two processes of plasma cold bed furnace and electron beam cold bed furnace smelting. Electron beam cold-hearth melting has many advantages over vacuum arc melting:

1 Various forms of raw materials such as residual materials, loose titanium sponge and titanium shavings, and economical raw materials can be used;

2 It can remove high-density impurities such as molybdenum (Mo), tungsten (W) and tantalum (Ta), low-density impurities such as cyanide and volatile impurities, and is an important technology for pure titanium alloy materials;

3 Improve the yield of metals by producing ingots of various cross-sections.

Information from Stanford Advanced Materials (SAM) Corporation, a global sputtering target manufacturing company.