Charles Bishop

Loughborough University | Lough · Department of Chemistry

Roll to roll metallizing is an important process for improving packaging applications by enhancing barrier properties to water, oxygen, light and chemicals such as; aromas, package flush gases etc. There are other applications such as; decorative coatings, functional coatings and security applications. This chapter looks at these applications and d...

There has been an interest in using polymer films as an alternative to glass substrates. Polymer substrates have the potential to reduce manufacturing costs by using roll-to-roll processing. Polymers also have improved flexibility and can reduce the weight of the final product. Many touch screens are constructions where two transparent conducting c...

There are three main problems relating to reactive sputtering—target poisoning, which leads to arcing; the disappearing anode; and the hysteresis of the reactive process that is particularly bad with underpumped systems. There are two types of preconditioning. First, there is the preconditioning of alloy targets. Initially, targets have to sputtere...

Adhesion is one of the core requirements for most vacuum deposited coatings, but is one of the more difficult properties to test. There are many possible tests, but few are easy to carry out and may be testing an applied adhesive or the operator carrying out the test. The best test is the fragmentation test, but this requires a microtensile testing...

To keep the polymer web reasonably cool, plasma chemical vapor deposition (CVD) tends is used. The basic process comprises feeding a precursor gas into a vacuum plasma. The plasma has energetic particles and the precursor gas is fragmented. Some of the molecules hit and condense on the substrate surface. Raising the substrate temperature increases...

This chapter focuses on several factors that need to be considered when making a decision to buy magnetron. One of the factors considered is the single or dual magnetron sputtering source. When sputtering from a target, there will be parts of the surface that are not sputtered or sputtered at a very slow rate. There will be backscattered material t...

The technique of atomic layer deposition (ALD) has evolved significantly in the recent years. It can be regarded as a special type of chemical vapor deposition (CVD). The process that consists of introducing a precursor gas that will attach to all surfaces, as a monolayer, is known as chemisorption. Once the whole surface is covered by a monolayer...

Most of the vacuum coating done is thin metal coating for packaging applications covering many aspects of packaging. The metal coatings can be bright and highly reflective providing more advertising impact than metallic inks, which are duller. The metalized polymer webs can be used directly by heat sealing, laminated to other webs, or have the meta...

Several things can be achieved by the treatment of webs and foils such as cleaning, sealing, physical etching, or functionalization. The choice of treatment method will depend on the web/foil to be treated and the effect that is required as well as cost and availability of pretreatment winding machines. In treating the surface, which includes bomba...

This chapter provides an introduction to the number of gauges available in the market. One of the types of gauges is capsule gauge, which uses a tube that is sealed at one end and open to the vacuum. As the system is evacuated, the tube distorts. This movement is converted via levers and gears into a dial movement. This gauge is aimed at checking t...

Coating processes are aimed at transferring a liquid onto a web. The simplest forms of coating process rely on the viscosity of the liquid to control the thickness and uniformity. Coatings applied at atmospheric pressure have solvents added to reduce the viscosity and so assisting flow and leveling. There are many coating options; however, some can...

A vacuum is described as where within an enclosed volume there is less gas per unit volume than is present in a similar volume in the atmosphere surrounding the enclosed volume. Many materials, particularly when raised in temperature to the boiling point, are prone to oxidation. Thus, an advantage of operating in a vacuum is that materials that wou...

The design of metalizers has evolved significantly in the recent years. The winding speeds have increased and are currently around 1000 m/min. If the winding speed increases, there has been a requirement for increases in roll length. This allows the proportion of machine uptime to downtime to remain constant as the winding speed increases further g...

Polymer webs can be manufactured by a number of different processes. The most widely used are the bubble process and the stenter process for the biaxial orientation of an extruded polymer. A minority of polymer is made using the casting process where the monomer or solution is cast onto a moving belt. The polymer web manufacturers should be encoura...

Several hazards fall into many different categories that include mechanical, electrical, thermal, chemical, and ergonomic. All vacuum systems have a method of opening the system. Large vacuum coaters often have a large door to the system that presents some hazards. If the door moves back on a track, there is the possibility of a trapping hazard if...

The drum surface roughness determines the number of contact points per unit area. It is relatively easy to manufacture polymer webs with a high-quality smooth finish. However, if both sides of the polymer are equally smooth, the polymer will block when wound in vacuum. The deposition rate and the winding speed are often linked. For a coating of the...

This chapter presents several issues that need to be considered in any system design. When presented with a proof-of-principle process, which has to be scaled up, it is required to look at all the design options, listing the pros and cons of each option, and iterating toward a design. This will include choosing between continuous and batch process,...

Several techniques have to be employed before a machine is built in order to reduce the risks. Chemometrics is a technique of analyzing data, looking at the natural excursions of parameters during a normal operation of the system. Using mathematical techniques such as principal component analysis (PCA), hierarchical cluster analysis (HCA), known ne...

The manufacturer building the vacuum system will design the appropriate winding system. The vacuum system will often be separated into two separate zones, the winding zone and the deposition zone. One aim tends to be to minimize the chamber volume and so the winding system will be made as compact as possible. In many cases, the winding zone volume...

The bulk of aluminum evaporation is done by passing a current through an intermetallic boat, thus heating it up and simultaneously feeding a wire of aluminum against the hot surface of the boat. The aluminum is supplied as a wire that is directed to feed into the boat at a shallow angle touching the boat surface toward the middle of the boat. Ideal...

This chapter provides an introduction to several methods for patterning that include both atmospheric processing and in vacuum patterning techniques. There are different options with the atmospheric patterning process. One of which produces a positive pattern and the other a negative of the same pattern. In order to reduce costs it is preferable to...

It is not always possible or convenient to use a resistance-heated boat. Some materials interact with the source boat and others are not suitable for wire feeding. This chapter presents several alternative methods of heating that may used. One of the sources is radiant-heated sources in which the material to be deposited sits in a crucible and the...

There are elaborate shields and source designs made to aid across-the-web uniformity, but little may have been done with respect to the pumping performance and uniformity. This chapter looks at these two aspects of the process. High pumping offers several benefits such as the high gas throughput means that the reactive gas partial pressure excess c...

There can be as many threats to the business as there are opportunities. Currently, there are developments in conducting polymers, printing technology, atmospheric processing, and, more recently, atmospheric atomic layer deposition that will be a threat to some vacuum web coating processes in future. An instance of taking a global view could be for...

This chapter provides an overview of two types of leaks—real and imaginary. The system pressure in a vacuum system that is pumped down and sealed off would rise and continue rising until it reaches the atmospheric pressure if there is a real leak. The pressure would rise initially in a system that is pumped down and then sealed off in case of imagi...

Polymer webs have a limited heat capacity before the heat relaxes the bonds such that the polymer will shrink, so it is common to aim to balance the heat load with an equal amount of cooling. The most common form of cooling is done using a liquid-cooled deposition drum. This can be extended by using pre or postdeposition cooled rolls. Although it i...

If a tube containing a cathode and an anode, which are positioned some distance apart, is evacuated and an inert gas is introduced, it is possible, when a potential is applied to the electrodes, to stimulate the system and for it then to become luminous. This emission of light is referred to as a glow discharge or plasma. The basic is that when eno...

Roll-to-roll vacuum deposition is the technology that applies an even coating to a flexible material that can be held on a roll and provides a much faster and cheaper method of bulk coating than deposition onto single pieces or non-flexible surfaces, such as glass. This technology has been used in industrial-scale applications for some time, includ...

This chapter focuses on vacuum metallizing used in flexible packages. Metallizing is still the most dominant process in packaging and its four main areas of use are decorative or aesthetic, barrier, functional, and security coatings. Decorative coatings for packaging began with the simple metallization of polymer films and papers, which gave the we...

Physical Vapour Deposition (PVD)Plasma Enhanced Chemical Vapour Deposition (PECVD)Electron Beam Evaporation SourcesInduction Heated Evaporation SourceMagnetron Sputter Deposition SourcesAtomic Layer Deposition (ALD)Other Deposition Processes

This chapter explores the aspects of the design and building of the magnetron sputter sources to understand how the source operates and which features can affect the sputter source deposition systems. Three different configurations of magnetrons are discussed to present how changing the position and strength of the magnetic pole pieces can affect t...

In troubleshooting, one of the real dangers is in trying to solve the wrong problem. While troubleshooting process, first one needs to verify the given information and define the problem. Then, it is required to systematically go through the process and question what has changed between a good process cycle and the problem process cycle. Included i...

A filament can be raised in temperature to become white-hot using a low-voltage and high-current power supply. The power to the filament can be either AC or DC. With such high currents being used, a magnetic field is created by the current flowing through the wire, and this will affect the electron emission. The quantity of electrons emitted depend...

There are three main problems relating to reactive sputtering, target poisoning that leads to arcing, the problem of the disappearing anode, and the hysteresis of the reactive process that is particularly bad with underpumped systems. Different strategies have been adopted to reduce the effects of these problems. This has included separating the in...

It is critical to have some form of monitoring in order to control the deposition process. There are various measurement options and it depends on the deposition process and the coating deposited as to which technique is used. For conducting coatings and using a calibration of the conductivity to the coating thickness, it is possible to monitor the...

This chapter discusses the available options to design planar magnetron. There are number of options on which a decision needs to be taken, such as single or dual magnetron, including an anode or not; balanced or unbalanced magnetic confinement; fixed or variable magnetic performance; and internal or external mounting for the source. The cost of th...

There are several characteristic steps to the initial growth of coatings. These are nucleation, coalescence, network, percolation threshold, holes, continuous, and film growth. In sequence of nucleation, the atoms arrive at the surface where they can stay or leave. The atoms that stay are absorbed on the surface and those that leave are desorbed or...

Substrates are an important variable in vacuum deposition processes. Polyethylene terephthalate (PET) film without any treatment has very smooth surfaces and these, when wound up, would have many contact points with high friction between the surfaces. This would prevent the surfaces slipping over each other, a problem known as blocking, which produ...

The need to determine the gas composition within commercial vacuum processes, led the development of mass spectrometer systems that are known as residual gas analyzers (RGAs), which are used for partial pressure-analysis. The helium leak detector is a specialized mass spectrometer. The design and electronics are all designed to optimize the sensiti...

This chapter presents the various examples of vacuum-coated products. It starts with the metallized films. In a Metallized coating aluminum is deposited using an aluminum wire-fed resistance heated evaporation source. Optical data storage is included in this group as it is based on an aluminum coating and can be deposited by a high-quality metalliz...

A vacuum could be described as the space within an enclosed volume where there is less gas per unit volume than is present in a similar volume in the atmosphere surrounding the enclosed volume. This can be used to one's advantage as one can reduce the boiling point of materials when under vacuum. Many materials, particularly when their temperature...

There are many pump types available and many different combinations of pumps that can be used to pump a system for any particular process. One of the types of pumps is the rotary pump that can be made with two different chambers so that the exhaust of one chamber is further increased in pressure by going through a second stage of compression. Roots...

Linear, uniform, high density plasma sources can be realized using linear microwave field applicators. Such systems can be applied to process large surfaces of materials that can be made to move transversely across the plasma source. This paper details the design and operating characteristics of appropriate linear applicators that are of the leaky-...

The compound metal TiN shows solar selective properties both in bulk and thin film form. It has previously been suggested that thin films of TiN, when anti-reflected by TiO2 layers, would form a hard and durable solar selective coating. We have made such multi-layer films and report on their properties. This paper also describes a new sputter coate...

The influence of the magnetic field strength and distribution on the operating characteristics of a planar magnetron has been investigated with permanent and electro-magnet units. The electro-magnetron will give variable magnetic fields of 0–30 mT at the centre of the race track. Increasing the field up to around 25 mT (250 Gauss) gives sharp impro...

Tungsten oxide can be produced as a thin film with a variety of compositions and doping to give coloured films which can be electrochromic. Electrochromic films are of interest in large areas as solar control devices and as alternatives to liquid crystal display panels. The preparation of such films by reactive planar magnetron sputtering is descri...

The appearance of optical filters on large scale as heat reflecting coatings on domestic windows, heralds the advent of techniques and materials for a range of applications which are far removed from the ultra-high performance, and cost, of multilayer filters used hitherto. These new coatings use interference anti-reflection layers on either side o...

Any system for the utilisation of solar energy requires to be of large area because of the low energy density of the radiation. It also requires to be highly thermally insulating to prevent the loss of low temperature heat that is gained. To be cost-effective in any application requires that a coating made to improve a system has to be made in larg...

The properties of metal filters with tin oxide dielectric matching layers is reported here when they are made by planar magnetron sputtering onto a flexible polyester sheet. Comparison with theoretical predictions indicate the point at which the structural effects in the film dominate the properties obtained.Silver films give visible transmittances...

Oxide films were made in a continuous process onto plastic sheet would from reel to reel over a drum exposed to the sputtering material and residual active gas. Single and double coaxial magnetron sources were used to create conducting elemental oxides of indium, cadmium, tin and zinc and alloy oxides of a combination of these materials. Optimum st...

The use for coatings in the fields of the utilization of solar energy and the provision of highly thermally insulated enclosures will depend on their performance, cost and availability on a large scale to allow their significant use. Filters utilizing highly doped large band gap oxide semiconductors and thin metals are described, when made by a dc...

TiO2 films have been produced from a variety of sources utilising various ion assisted techniques to provide surface energy. It was found that reactive rf bias ion plating using electron beam evaporated titanium metal could give films of refractive index of close to 2.5 and equivalent to those made by conventional reactive evaporation onto substrat...

A technique of vacuum deposition is described for producing heat reflecting films onto sheet plastic for application in domestic windows. Thin metal films of copper, silver, gold and titanium nitride sandwiched between dielectric films and electrically conducting oxide coatings of indium, indium doped with tin and cadmium/tin are shown to have the...

The provision of coatings to utilise solar radiation and to Prevent heat radiation loss creates many Problems in their design and creation. They must be simple and be able to be manufactured in very large areas to meet the cost and application requirements. The use of optical Properties given to materials by their free carrier concentration is cons...

Methods of deposition were developed which are adapted for the vacuum roll-to-roll coating of plastic with optical thin films. Planar magnetron sputtering and low pressure plasma assisted CAD are shown to be peculiarly fitted for this application. The construction of such an apparatus is described and examples of indium and indium-tin oxide films m...

A plasma-aided deposition technique was used to prepare thin oxide coatings by the reaction of volatile chlorides with oxygen. A 13.56 MHz r.f. supply was connected to a circular electrode on which the substrates were supported. A glow discharge was set up at pressures between 5 and 100 m Torr, and a self-bias on the electrode of between − 100 and...

Ion plating onto plastic substrates was demonstrated to give considerable advantages in that adhesion is increased and properties can be obtained which would normally require higher temperatures than the substrate is capable of withstanding. In order to coat large areas of sheet plastic it is necessary to achieve high deposition rates without creat...

In general there are two ways of producing a highly transparent film which is also electrically conducting: (1) the use of a highly degenerate semiconductor film which has a sufficiently high energy gap to be transparent in the visible region; (2) the use of a very thin metal film with the onset of the high reflection suppresed by interference supp...

Silver films were deposited under the ion-plating conditions of an r.f. plasma directed towards the plastic substrate. The plastic polyethylene terephthalate was plasma etched and for some experiments was coated with 20 nm of titanium oxide. Both planar-magnetron-sputtered material and electron-beam-evaporated material were investigated when ion pl...

Carrier concentrations and mobilities of vacuum‐prepared indium–tin oxide films have been measured to determine the effects of annealing. The apparent variation of electron mobility with temperature in these films is interpreted in terms of a grain‐boundary barrier model. No grain growth was observed in the films studied; all changes in electron de...

Transparent conducting oxide films were produced by the reactive ion plating of indium onto glass and plastic substrates at room temperature. The electrical properties of these films were sufficient, with high values of electrical mobility and carrier density, to give a sharp plasma reflectance edge in the near infrared. These properties are ideall...

The variation of structure with bias voltage, created by an r.f. discharge directed towards the substrate, of magnetron-sputtered films of indium oxide was determined by transmission electron diffraction techniques and showed a preferred (222) orientation parallel to the substrate. A technique for the reliable separation of thin films from a polyes...

Indium and indium 10% tin oxide films have been produced on room-temperature insulating substrates and have exhibited high conductivities which compare with the best reported for films made at substrate temperatures of 450 °C and higher. They were made by the evaporation and sputtering of the metals in an atmosphere of argon and oxygen onto...

The term “ion plating” is applied to atomistic deposition processes in which the substrate is subjected to a flux of high energy ions, energetic neutrals, and active species sufficient to cause sputtering before and during film deposition. The ion bombardment can be done in an inert, reactive or mixed gas radio-frequency discharge system where the...

SnO2 and In2O3 films were produced by evaporation and by magnetron sputtering of the elements in an atmosphere containing oxygen. The insulating substrate of glass or plastic was water cooled and made one electrode of an r.f. discharge in the gas. The optical and electrical properties of the films indicated that the energy of the bombarding ions, m...

Transparent conducting oxide films have been produced by the reactive ion plating of indium onto glass and plastic substrates at room temperature. The electrical properties of these films were sufficient, with high values of electrical mobility and carrier density, to give a sharp plasma reflectance edge in the near infrared. These properties are i...

A planar magnetron sputtering source, having plasma confinement by a magnetic field provided by an arrangement of permanent magnets, has been used in a conventional vacuum system to prepare transparent conducting films of the oxides of indium and indium-tin alloys. During deposition, the substrates were subjected to an r. f. discharge - the ion-pla...

Aluminium metallizers have a row of resistance heated evaporation boats sited beneath a chilled deposition drum. Each boat has aluminium wire fed into it that forms a molten pool from which the aluminium evaporates. This process has low material efficiency and there is a significant ongoing cost in replacing the evaporation boats after every 12 - 1...

In the future metallizers, to remain competitive, will have to offer something more than they currently do. Inevitably one of the pressures exerted by the markets will always be price. To compete on price either the same coating has to be offered at a lower price, or something else has to be given to maintain or possibly even increase the price. To...

Planar magnetron sputtering using metal targets and dc power has been shown to be a very suitable source for the reactive preparation of oxide films. It is very stable, and capable of fine control and may be operated in a residual atmosphere containing oxygen. It provides a high energy depositing species which allows the preparation of films at roo...

A double magnetron, with a divided field to give two concentric 'race-tracks' and with independent power supplies, is described. This allows the composition of film alloys to be varied without the considerable trouble and uncertainty of creating the alloy target material, which is not always possible. A design using a central hole has allowed us to...