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.

Image Gallery of SAM Evaporation Materials

High purity evaporation materials play a huge role in deposition processes to ensure high quality deposited film. Stanford Advanced Materials provides various evaporation materials for both thermal and e-beam evaporation, including metal and ceramic boats, filaments, crucibles and heaters, and e-beam crucible liners.

Image Gallery of SAM Sputter Targets

Stanford Advanced Materials (SAM) Corporation is a global supplier of various sputter targets such as metals, alloys, oxides, ceramic materials. We provide sputtering targets for a wide range of applications from ferromagnetic, complex oxides, and semiconducting films.

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.

History and Development of Copper

Sorry for that we have not updated the “Metal History” column for a long time. For previous posts of this column, please search the keyword “history”. Today, let us unveil the history 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.

Part of the reason for it being used so early is simply that it is relatively easy to shape. However, it is somewhat too soft for many tools and around 5000 years ago it was discovered that when copper is mixed with other metals the resulting alloys are harder than the copper itself. As examples, brass is a mixture of copper and zinc while bronze is a mixture of copper and tin. For many centuries, bronze reigned supreme, being used for plows, tools of all kinds, weapons, armor, and decorative objects.

Mesopotamia, circa 4500 BC

Pure Metal is ineffective as a weapon and tool because of its softness. But early metallurgy experimentation by the Mesopotamians resulted in a solution to this problem: bronze, an alloy of copper and tin, was not only harder but also could be treated by forging (shaping and hardening through hammering) and casting (poured and molded as a liquid).

Mesopotamia copper

The ability to extract copper from ore bodies has been well developed. In today’s Armenia, bronze and copper alloy tools, including chisels, razors, harpoons, arrows and spearheads, have been traced back to the third millennium BC. A chemical analysis of bronze from the region indicates that common alloys of the time contained approximately 87 percent copper, 10 to 11 percent tin, and small amounts of iron, nickel, lead, arsenic, and antimony.

Egypt, circa 3500 BC

The use of copper in Egypt developed almost at the same time as Mesopotamia. The copper pipe used to transport water was used in the King Sa’Hu-Re temple in Abusir, 2750 BC. These tubes are made of thin copper plate with a diameter of 2.95 inches (75 mm) and a pipe length of nearly 328 feet (100 m). The Egyptians also used copper and bronze as mirrors, razors, utensils, weights and balances, as well as obelisks and ornaments on temples. According to biblical references, the Egyptians used a large number of bronze pillars on the porch of the Solomon Palace in Jerusalem (circa 9th century BC), which were 6 feet (1.83 meters) in diameter and 25 feet (7.62 meters) high.

Egypt copper

China, circa 2800 BC

By the year 2000 BC, bronzes were produced in large quantities in China. Bronze castings found in Henan and Shaanxi provinces and surrounding areas are considered to be the beginnings of Chinese bronzes, although some copper and bronze artifacts used by the Majiayao have been dated as early as 3000 BC.

China copper

Relevant literature shows the direction of metallurgy in China, and discusses in detail the exact proportions of copper and tin used to produce different alloy grades for casting different items such as cymbals and bells, axes, spears, swords, arrows and mirrors.

Modern Development

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%.

Information provided by SAM Sputter Targets.

Related Copper Products: Copper Sputtering Target

Guide Book: Sputtering Targets Preparation, Cleaning, Installation and Packing

Preparation before using the target

It is very important to keep the vacuum chamber clean. Residues formed during target sputtering collect moisture and other contaminants, directly affecting the success rate of vacuum coating. If the sputtering chamber is not clean enough, the sputter gun and the sputtering target will often short-circuit or exceed the target arc to discharge, filming surface roughness and chemical impurities. In addition to the vacuum chamber, the dark area shield, cavity walls and adjacent surfaces need to be kept clean. When cleaning the vacuum chamber, we recommend using a glass ball to blast the dirty parts, while using compressed air to remove spilled residue from the periphery of the cavity, and then gently polishing the surface with alumina impregnated sandpaper. After polishing, wash with alcohol, acetone and deionized water. It is recommended to use an industrial vacuum cleaner for auxiliary cleaning.

In addition, in order to ensure coating characteristics, it is also necessary to wash and dry the sputtering gas (argon or oxygen). After the substrate is placed in the sputtering chamber, air needs to be extracted to achieve the vacuum state required for the process.

When using the target, wear clean protective gloves and avoid direct contact with the target.

Target cleaning

The purpose of cleaning the sputtering target is to remove any dust or dirt that may be present on the target surface. Metal sputtering targets can be cleaned in four steps:

In the first step, the target is wiped with a soft, lint-free cloth soaked in acetone;

The second step is to clean the target with alcohol;

The third step is to wash the target with deionized water;

In the fourth step, the target was placed in an oven and dried at 100 degrees Celsius for 30 minutes.

For oxide ceramic sputtering targets, it is recommended to use a “langue-free cloth” for cleaning. After removing the contaminated area, the target is flushed with high pressure, low moisture argon to remove any contaminating particles that may create an arc in the sputtering system.

Target cleaning

Target installation

During target installation, it is important to ensure a good thermal connection between the target and the stabilizing wall of the sputter gun. If the degree of warpage of the stave or backing plate is severe, the thermal conductivity of the target will be greatly affected, resulting in heat not being dissipated during the sputtering process, eventually leading to cracking of the target.

Target packaging and transportation

All targets should be packaged in a vacuum-sealed plastic bag with a moisture barrier. The outer packaging is usually a wooden box with an anti-collision layer around it to protect the target and rear targets from damage during transportation and storage.

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

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.