TW201728766A - Coated flexible component - Google Patents

Abstract

The invention relates to a coated flexible component (1), in particular a coated flexible electronic component, containing a flexible substrate (2) and at least one metallic coating based on refractory metal (3). The coating based on refractory metal (3) contains more than 6 at% and less than 50 at% of Re. The invention additionally relates to a process for producing a coated flexible component (1) via provision of a flexible substrate (2) and deposition of at least one metallic coating which is based on refractory metal (3) and contains more than 6 at% and less than 50 at% of Re.

Description

Coated elastic component

The invention relates to a coated elastomeric component, in particular a coated elastomeric electronic component, comprising an elastomeric substrate and at least one metallic coating based on a refractory metal. The invention is additionally directed to a method of making a coated elastomeric component.

Technological advances in the field of elastomeric components are closely related to advances in the field of thin film materials. In particular, this progress has led to further developments in the field of electronic devices, particularly enabling thin film components such as thin-film transistors (TFTs). Furthermore, advances in the development of new integration processes have also allowed electronic devices to be combined with flexible substrates, making it possible to manufacture elastic electronic components.

The development and optimization of thin film materials that have occurred for decades has now led to many advantageous methods of making film components. Thus, such film components can be produced, for example, on large-area substrates to be extremely inexpensive and of consistent quality. The two most widely used examples of this type of film component are diodes and transistors, which are used in many digital and analog circuits and also as sensor elements and for energy recovery.

In the field of electronic equipment and electronic products, especially consumer electronic equipment, the current development is increasingly determined by the design of the "form follows function". Elastic components have become even more important for implementing this design concept in modern products. The (elastic) form factor is a key parameter. The elasticity of the components and therefore the supplies (also known as bendability, deformability) A large number of areas of use will be opened in the future, for example in the health block, the automotive industry, the human-machine interface (HMI) or the graphical user interface (GUI), new types of computer platforms, Mobile telecommunications, energy management and more.

There are already a large number of prototypes in the field of elastic electronic products. These often use exotic new materials (such as graphene, carbon nanotubes, organic semiconductors...) and precious metals in order to obtain the desired properties. Such prototypes are not very suitable for mass production because of cost factors, and are often only of academic interest. For consumer electronic devices, it is often attempted to transfer the established film process from a rigid substrate (such as glass, germanium) to an elastic substrate (such as a polymer film).

Moreover, the patent literature is also associated with the field of elastic electronic components. Thus, for example, U.S. Patent Publication No. 2014 0170413 A1 discloses various methods of producing an coated body having an elastic substrate. In the described method, various layers of transparent conductive oxide and doped or alloyed silver are deposited on the elastomeric substrate.

This type of elastomeric component (especially elastic electronic components) for displays, wearable and portable devices, medical technology (eg medical devices, sensors, implants), energy generation, energy management and energy storage It has become even more important for applications such as flexible solar cells, thin-film batteries, capacitors, automotive, roofing or building technology (such as in sensors, smart glass). These components must withstand high elastic deformation during operation or installation, for example bending or tensile stress. These stresses are often also cyclic and have stringent requirements on the mechanical properties of the materials used for these components.

The conductive or conductive track structure of such an elastomeric electronic component is often composed of Cu, Al, Ag, Cu-based, Al-based or Ag-based alloys or noble metals (e.g., Pt and Au) due to the need for low electrical resistance. Although alternative materials (such as graphene, carbon nanotubes, conductive polymers) Extremely elastic, but having a conductivity that is worse than the metals or precious metals described above, they are currently only used in simple components.

Although Pt and Au have excellent electrical conductivity and excellent oxidation resistance and corrosion resistance, they are not suitable for large-scale use because of cost.

Cu, Al, Ag, Cu-based, Al-based or Ag-based alloys have high elongation at break. However, they only show a low barrier to resist the diffusion of impurities (inwards). Such diffusion can occur, for example, from the substrate or other layers of the component into the conductive track, but also from the conductive track into the semiconductor. Thus there is a risk that the components of Cu, Al, Ag or Cu, Al or Ag alloys diffuse into the semiconductor and destroy the properties of the semiconductor. Incidentally, Cu, Al, Ag, Cu-based, Al-based or Ag-based alloys have only low corrosion resistance. For components that are also to be used in environments with relatively high atmospheric humidity, these materials can therefore only be used to a limited extent and are electrically conductive consisting of Cu, Al, Ag, Cu-based, Al-based or Ag-based alloys. The rail requires an additional cover layer and/or barrier layer depending on the use of the individual components.

A further important benchmark for the function of the elastomeric component is that one or more layers applied (for example, conductive rails) are properly attached to the substrate. Because of this, an appropriate bonding layer is additionally applied depending on the substrate used.

For rigid electronic components, it is customary to use a layer composed of a refractory metal such as Mo, W, Ti, Ta, Cr and alloys thereof as a barrier or bonding layer or as an anti-oxidation or corrosion-resistant coating. Therefore, the molybdenum-niobium alloy layer is used for the contact sensor arrangement, for example, as described in U.S. Patent Publication No. 2011199341 A1. The layer consisting of refractory metals has the added advantage of being applied between the conductive track and the semiconductor layer present to create an ohmic contact between the conductive track and the semiconductor.

However, refractory metals and their alloys often have poor deformability due to their body-centered cubic crystal structure, and have toughness (resistance to crack formation and crack propagation) for the use of elastomeric components. Too low. Because of this, the use of refractory metals in components which must have high elasticity has not yet led to satisfactory results. Cracks in the joint layer can be transferred to the conductor rails, for example. This causes cracking to be induced in the conductor rails and additionally causes cracks to pass through the entire width of the conductor rails. As a result, the resistance is greatly increased; and in extreme cases, the conductive tracks are no longer electrically conductive.

Although bodies or samples (monolithic materials) composed of refractory metal alloys and extending in all three directions in space have been studied, the goal is to increase ductility and impact toughness (for example, refer to the metallurgy of Leichtfried et al. And Materials Newsletter A , Book 37A, October 2006, pp. 2955~2961), but the film has not been studied. However, examples of pure molybdenum may, for example, show that the properties of the film can be substantially different from the properties of the body extending in all three directions in space. Thus, molybdenum typically has an elongation of about 10% at room temperature when fractured, depending on the microstructure, residual stress, and recrystallization state. On the other hand, the molybdenum film has an elongation of only 1 to 2% at the time of fracture.

It is therefore an object of the present invention to provide an elastic component that avoids the aforementioned problems and disadvantages. The composition should have a significantly improved toughness compared to prior art techniques, i.e., increased resistance to crack formation and crack growth. It is a further object of the invention to provide a method of making an elastomeric component.

This object is achieved by providing an elastic component having the features of claim 1 and a manufacturing method as set forth in claim 15 of the patent application. A particular aspect that is advantageous is the subject matter of the patent application scope.

For this purpose, elasticity and "flexible" refer to the property of absorbing or withstanding flexural stress without detrimental effects on the nature of the component concerned. The sufficiently elastic component therefore also has a significantly improved toughness.

For the purposes of the present invention, significantly improved toughness means that the component (one or more layers present in nature) has increased resistance to crack formation and crack growth, and the crack thus does not form a particular strain, but only Formed at higher strains or with modified crack profiles.

To describe toughness and hence resilience, the context of the present invention uses critical strain. The critical strain is defined as the strain ε _k at which the resistance R of one or more layers on the elastic substrate is increased by 20% (R/R ₀ = 1.2) compared to the initial state. In the case where the composition has a sufficiently high elasticity, the critical strain ε _k is significantly increased, so that the electrical conductivity of one or more layers is maintained significantly longer.

According to claim 1 of the patent application, there is provided a coated elastomeric component comprising an elastomeric substrate and at least one metallic coating based on a refractory metal. The refractory metal-based coating contains greater than 6 at% and less than 50 at% bismuth (Re).

For the purposes of the present invention, refractory metal-based expression refers to an alloy based on one or more refractory metals, and the proportion of one or more refractory metals constitutes greater than 50 atomic percent of the total alloy. The refractory metal is a metal such as Mo, W, Ta, Nb, Ti, or Cr.

At a Re (铼) content of up to 6 at%, the elasticity of the metallic coating based on the refractory metal and thus the elasticity of the elastic component have not been sufficiently confirmed.

For the purposes of the present invention, an elastic substrate is one in which one or more layers of strain ε deposited thereon are applied (coated) under application of flexural stress. If one or more layers are much thinner than the substrate, the strain is approximated by ε = d _s /2R (d _s is the thickness of the substrate and R is the radius of curvature). If one or more layers are extremely thin compared to the substrate, the strain in one or more layers can be written to approximate a pure tensile or compressive stress. For example, the elastic substrate can be based on one or more polymeric materials, such as polyamine, polycarbonate, polyethylene terephthalate or polyethyl naphthalate. Most elastomeric substrates based on one or more polymeric materials have an E modulus of less than or equal to 8 billion Pascals (GPa). Thin glass (glasses less than 1 mm thick), metal foils (for example steel sheets having a thickness of less than 1 mm) or mineral materials (such as mica) are also elastic substrates suitable for use in the elastic component according to the invention.

The elastic substrate suitable for the purpose of the present invention may also be composed of one or more layers or one or more materials. Similarly, such a substrate may have been coated, in whole or in part, with one or more layers of other materials.

This component is preferably a coated elastomeric electronic component. The coated elastomeric electronic component has at least one layer that conducts current relative to the coated elastomeric component (eg, an encapsulating film with a metallic gas barrier layer or optical layer). This is exemplified in the case of an elastic circuit, an elastic display, an elastic sensing element, an elastic film capacitor, an elastic thin film battery, or a simple conductive film.

In accordance with the present invention, the refractory metal based coating of the coated elastomeric component preferably comprises greater than 6 atomic percent and less than 35 atomic percent Re. At levels greater than 35 atomic percent, it is possible to form an intermetallic phase between one or more refractory metal or refractory metal substrates and Re. The formation of such intermetallic phases can result in reduced toughness in certain alloys. Furthermore, too high a Re content is no longer sensible in many cases because of the high cost of raw materials.

According to the invention, the refractory metal-based coating of the coated component particularly preferably comprises 10 atomic % or more of Re. At a Re content higher than 10 at%, it is observed that the critical strain ε _{k is} particularly significantly increased (in the case of 20% pure MoRe coating).

According to the invention, the refractory metal based coating of the coated elastomeric component preferably has a thickness of less than 1 micron. The refractory metal based coating preferably has a minimum thickness of 5 nanometers, more preferably a thickness of at least 10 nanometers. It is also preferred to have a thickness of from 5 to 300 nm, and even more preferably from 5 to 100 nm. Such layer thickness is particularly advantageous when refractory metal based coating is used as the bonding layer. In the alternative, the preferred thickness ranges from 150 to 400 nm. A layer thickness of from 150 to 400 nm is particularly suitable for use in a display according to the coated elastomeric component of the invention, for example as a gate electrode layer.

According to the invention, the refractory metal based coating of the coated elastomeric component is also preferably a molybdenum based coating. This means that the proportion (atomic %) of refractory metal molybdenum is often present in refractory metal based coatings. The molybdenum-based coating may be, by way of example, Mo-Re coating, Mo-Nb-Re coating, Mo-Ta-Re coating, Mo-W-Re coating, Mo-Ti-Re coating. Cloth or Mo-Cr-Re coating. However, further coating based on molybdenum, for example a quaternary type of coating, is also possible. An example of this type would be Mo-W-Nb-Re coating.

Molybdenum-based coatings are preferred, especially because they have good adhesion to many substrate materials and they are well suited as diffusion barriers. A further cause is the formation of ohmic contacts with many semiconductor materials, particularly with germanium.

Alternatively, in accordance with the present invention, the refractory metal based coating of the coated elastomeric component is preferably based on tungsten coating, such as W-Re coating or WX-Re coating, Wherein X = Cr, Nb, Ta, Ti, Mo. Tungsten-based coating has a slightly improved barrier effect compared to molybdenum-based coating.

The elastic substrate of the coated elastomeric component according to the invention is preferably transparent. Transparent means light about part of the electromagnetic spectrum of the application (for example, visible light, near red) External light, ultraviolet light) are not absorbed by the elastic substrate or have only a small degree of absorption.

The elastic substrate of the coated elastic component according to the present invention preferably also includes at least one material from the group consisting of a polymer, a thin glass, a metal foil, and a mineral material. Combinations of the materials are also possible specific aspects. An elastic substrate composed of a polymer is particularly preferred based on cost and weight.

The thickness of the coated elastomeric component according to the invention is preferably less than 10 mm, particularly preferably less than 5 mm, and particularly preferably less than 2 mm. The coated elastomeric component according to the invention preferably has a minimum thickness of 10 microns, more preferably a thickness of at least 50 microns.

According to the invention, the refractory metal based coating of the coated elastomeric component preferably also has a critical strain ε _k which is 25% higher than the reference coating based on refractory metal without Re. The critical strain is determined as follows and gives information about the elasticity and toughness of the refractory metal based coating, which in turn affects the elasticity and toughness of the components.

By using MTS uniaxial stretching test Tyron 250 ^® universal testing machine, and in the sample coated on a substrate of a refractory metal-based decision up ratio R / R _0. Here, the sample (substrate and coating) was elastically deformed to a maximum strain ε of 15%. During the tensile test, a four-point method was used to continuously record the applied resistance R. The resistance of the initial state is specified as R ₀ . In the case of the measurement settings used, the sample length in the initial state (free length between the clamps) is 20 mm and the width is 5 mm. The measurement settings used are shown schematically in Figure 1. L is _constant indicating the length of the fixed clamp in which elongation does not occur.

The critical strain is defined as the strain ε _k at which the applied resistance R on the elastic substrate is increased by 20% (ie, R/R ₀ = 1.2) compared to the initial state.

In particular, it is preferred that the ratio R/R ₀ of the resistance (R ₀ ) of the resistance R to the start of measurement based on the refractory metal coating at 2% elastic strain ε is less than 1.2.

In the case of the coated elastic component according to the present invention, the cracked structure having a reduced proportion of parallel cracks perpendicular to the stress direction preferably occurs in the experimental arrangement as described above and shown in FIG. In particularly good cases, greater than 50% of the crack length is not perpendicular to the stress direction.

The coated elastomeric component according to the invention preferably has at least one electrically conductive track structure. For this purpose, the expression of a conductive track structure or a simple conductive track refers to a structure that conducts current and is often similarly applied to the layers. The coated elastomeric component having at least one conductive rail structure is a coated elastomeric electronic component.

Such a conductive rail structure may have been applied directly to the substrate of the coated elastomeric component. However, one or more further layers may also be provided and applied between the substrate and the conductive track structure. Such a conductive rail structure may be composed of a single layer, but may also be made of a series of multiple layers.

In a preferred embodiment, at least one of the conductive track structures of the coated elastomeric component according to the present invention has at least one metal layer composed of Cu, Al, Ag, Cu-based alloy, Al-based alloy or Ag-based alloy. . In the present case, the expression of a Cu-based, Al-based or Ag-based alloy means an alloy containing more than 50 at% of Cu, Al or Ag, respectively. A metal layer composed of Cu, Al, Ag, Cu-based alloy, Al-based alloy or Ag-based alloy has extremely high electrical conductivity, and as a result, it is particularly suitable for use in a conductive rail.

In a further preferred embodiment, the refractory metal based coating of the coated elastomeric component is part of at least one conductive rail structure in accordance with the present invention. Here, you can be in a variety of situations Make a distinction between shapes.

Thus, the refractory metal based coating can be, for example, the entire conductive rail structure. Refractory metals also have good electrical conductivity, so for some applications the current can be delivered in a satisfactory manner. Such a case is exemplified by a gate electrode in a thin film transistor.

In place of the selective embodiment, the refractory metal based coating is disposed on the side of the at least one conductive track structure that faces away from the substrate. In this case, the refractory metal based coating can function as a cover layer to protect against corrosion and/or oxidation.

In a further preferred embodiment, the refractory metal-based coating arrangement is between the elastic substrate and the metal layer composed of Cu, Al, Ag, Cu-based alloy, Al-based alloy or Ag-based alloy, that is, at least one The side of the conductive track structure facing the substrate. In this case, the refractory metal-based coating can function as a barrier layer, a bonding layer, or other layer that makes ohmic contacts.

In a further preferred embodiment, the coated elastomeric component according to the invention additionally comprises at least one half of the conductive layer. Such a semiconductive layer may be, for example, an amorphous, microcrystalline or nanocrystalline germanium, a metal oxide (for example, indium gallium-zinc oxide (IGZO) or tungsten oxide). Or a layer composed of a semiconductive polymer.

In yet another preferred embodiment, the refractory metal based coating is a partial TFT structure. A TFT (Thin Film Transistor) structure is an arrangement of thin film transistors that can be present in many coated elastomeric electronic components.

The coated elastomeric component according to the present invention is preferably derived from an elastic liquid crystal display (LCD), an elastic organic light emitting diode (OLED) display, an elastic electrophoretic display (electronic paper), an elastic solar cell, an electrophoresis A component in a group consisting of a color-changing elastic film and an elastic thin film battery. Especially particularly well, it is an elastic LCD display, an elastic OLED display or an elastic electric Swimming display.

The method of making a coated component, in particular a coated elastomeric electronic component, according to the invention comprises at least the steps of: providing an elastic substrate; characterized by at least one metallic coating based on depositing a refractory metal The refractory metal-based coating contains more than 6 atomic % and less than 50 atomic % of Re, while the elastic substrate is coated.

Therefore, a suitable elastic substrate is provided. For the purposes of the present invention, an elastic substrate is a substrate that is subjected to flexural stress resulting in strain in one or more layers applied to the coating. If one or more layers are much thinner than the substrate, the strain is approximately described as ε = d _s /2R (d _s is the thickness of the substrate and R is the radius of curvature). If one or more layers are extremely thin compared to the substrate, the strain in one or more layers can be written to approximate a pure tensile or compressive stress. For example, the elastic substrate can be based on one or more polymeric materials, such as polyamine, polycarbonate, polyethylene terephthalate or polyethyl naphthalate. Most elastic substrates based on one or more polymeric materials have an E modulus of less than or equal to 8 GPa. Thin glass (glasses less than 1 mm thick), metal foils (for example steel sheets having a thickness of less than 1 mm) or mineral materials (such as mica) are also elastic substrates suitable for use in the elastic component according to the invention.

Elastomeric substrates suitable for the present invention may also be constructed from one or more layers or one or more materials. Such a substrate may be similar to other materials that have been completely coated in advance or only partially coated with one or more layers.

Furthermore, at least one metallic coating is deposited, which is based on a refractory metal and contains greater than 6 atomic % and less than 50 atomic % Re. The deposition of at least one metallic coating based on the refractory metal can be achieved by a wide variety of deposition processes. For example, such coating can It is achieved by physical or chemical vapor deposition.

However, the deposition of at least one metallic coating based on refractory metal is advantageously carried out by a PVD process, in particular a sputtering process. The PVD (physical vapour deposition) process is a known thin film coating technique in which particles of a coating material are carried to a gas phase and then deposited on a substrate. A particularly homogeneous coating can be deposited by a PVD process, the properties of which are the same and uniform across the coated area. A further advantage of this process is that a low substrate temperature can be achieved thereby. This makes it possible, for example, to coat the polymer. Furthermore, the PVD layer shows excellent adhesion to the substrate.

In particular, refractory metal based coatings are deposited by a sputtering process (also known as a cathode atomization process). The sputtering process can be relatively simple for large-area homogeneous coating and is therefore an inexpensive mass production method.

In particular, the method of the present invention additionally comprises the step of providing a target based on a refractory metal and comprising from 6 atomic % to less than 50 atomic % Re.

Providing a target based on a refractory metal and comprising Re from 6 at% to less than 50 at% is performed prior to depositing at least one metallic coating based on the refractory metal. The metallic coating is therefore etched from the provided target.

For the purposes of the present invention, the target is the source of coating for the coating equipment. In a preferred process, the target used is a sputtering target for the sputtering process.

The chemical composition of the coating is determined by the chemical composition of the target used. However, the coating composition can deviate from the target composition due to the slightly different sputtering behavior of the elements in the target. For example, the Re content of the deposited coating can be increased slightly because The Re of the MoRe target is preferably sputtered. In order to produce a coating to contain more than 6 atomic % Re, the corresponding target may also contain less than 6 atomic percent Re. However, this behavior depends on the elements present in the target and can therefore be different for different targets with different refractory metal bases.

Metallurgical coatings based on refractory metals can also be deposited by co-deposition (preferably co-sputtering) of individual targets in an alternative to the use of a single target. In this case, the chemical composition of the coating can be additionally controlled by selecting different targets.

Sputter targets suitable for depositing refractory metal-based metallic coatings can be produced, for example, by powder metallurgy.

Possible powder metallurgy methods for making sputter targets are based on hot pressing techniques such as hot pressing (HP) or spark plasma sintering (SPS). In both cases, the powder mixture is introduced into a stamper, heated in a mold, sintered/densified at high temperature and pressure to give a dense component. Here, a homogeneous microstructure is obtained which has uniformly shaped grains and is not preferably oriented (texture).

A similar powder metallurgy method for making sputter targets is hot isostatic pressing (HIP). The material to be densified is in this case introduced into a deformable, impermeable container (often a steel can). The material to be densified may be a powder, a powder mixture or a green body (in the form of a pressurized powder). The material present in the vessel is sintered/densified in the vessel under a protective gas (such as Ar) in a high temperature, high pressure, pressurized vessel. Air pressure acts on each side, because this process is known as pressure equalization. Typical process parameters are, for example, 1100 ° C, 100 megapascals (MPa), and a holding time of 3 hours. Here, a homogeneous microstructure is obtained which has uniformly shaped grains and is not preferably oriented (texture).

A further possible way to make a sputter target via powder metallurgy is to burn Knot and subsequent forming. Here, the powder compact is sintered at a high temperature of hydrogen or reduced pressure. The sintering is followed by a forming step (such as rolling or forging) to achieve a high relative density of >99%. The microstructures established here have elongated grains and have a preferred orientation (texture). The optimized subsequent microstructure recrystallization annealing step gives a homogeneous microstructure with uniformly shaped grains, but continues to have a preferred orientation (texture).

A further possible way to produce a sputter target via powder metallurgy is to apply the powder or powder mixture to a suitable support structure, such as a plate or tube, by a thermal spray process, for example cold air spray.

The invention is described in more detail by the following examples and further explained with the aid of a chart.

<Example 1>

In many series of experiments, different metallic coatings based on refractory metals were deposited on a polyimide substrate. Here, coatings having different chemical compositions were made.

The composition of the metallic coating based on the refractory metal and the composition of the target used for its deposition are summarized in Tables 1 and 2.

Pure Mo in the form of a molybdenum coating and having a thickness of 200 nm was used as a reference material for the molybdenum-based alloy.

Furthermore, MoX coating (X=Cr, Nb, Ta, Ti, W) was also measured in each case, which similarly had a thickness of 200 nm to be coated with MoXRe (X=Cr, Nb, Ta, Ti, W) for comparison.

The ratio of Mo to X in the MoXRe alloy (atomic %) is the same as that of the MoX comparative alloy. The Re content of the MoXRe alloy (target for deposition) is always 15 atom% Re. Individual coatings are deposited from a sputtering target consisting of an alloy corresponding to a refractory metal.

All coatings are deposited at room temperature in a composition consisting of polyamidamine (PI, "Kapton") On a 50 micron thick film. The process parameters are kept constant in order to exclude as much as possible the effects of various process conditions on the results. The layer thickness is kept constant at 200 nm in order to avoid the effect of geometric effects on the results.

It is used on the coated sample panel polyalkylene acyl group MTS uniaxial stretching test Tyron 250 ^® universal testing machine. Here, the substrate is elastically deformed to a maximum strain ε of 15%. During the tensile test, a four-point method was used to continuously record the applied resistance R. The resistance at the beginning of the measurement is expressed as R ₀ . The sample length in the initial state (free length between the clamps) is 20 mm and the width is 5 mm. The measurement settings are shown schematically in Figure 1. L is _constant representing the length of the fixed clamp in which elongation does not occur.

The critical strain is defined as the strain ε _k when the applied resistance R of the elastic substrate is increased by 20% (ie, R/R ₀ = 1.2) compared to the initial state.

The critical strain ε _k determined by this tensile test is shown in Tables 3 and 4.

In the case of the MoRe alloy (Mo alone as the refractory metal matrix), no significant increase in the critical strain ε _k was observed when 6 atom% of Re was added. The critical strains of pure Mo and MoRe 6 at% are much the same; small differences can be explained by typical fluctuations in the measurement.

After the above tensile test, the test coating was examined under an optical microscope and a scanning electron microscope. Here, the crack shape occurring in the coating and the average interval between the cracks were evaluated.

For coatings based on brittle materials (e.g., pure Mo), crack patterns that typically behave as brittle materials often occur when the sample fails under tensile stress. This pattern is characterized by a straight, parallel cracked network that forms a right angle to the stress direction. Such a crack pattern can be seen, for example, in Figures 4a) (Mo) and 5. These straight cracks mostly pass over the entire width of the sample from side to side and also through the entire thickness of the coating. Such a crack is called a through thickness crack (TTC). TTC considerably reduces the conductivity of the coating because in the worst case, there is no longer any continuous electrical connection in the coating. As can be seen from the curves measured on the reference material, the resistance increases greatly with increasing strain. This can be observed in Figures 2 and 3, which show the increase in resistance (R/R ₀ ) versus the applied strain ε compared to the initial resistance; see Mo and MoX here (X = Cr, Nb, Ta, Ti, W) curve. The curve referred to by "theory" shows that the increase in resistance is only due to the change in the shape of the sample.

Figure 6 shows the critical strain ε _k from the failure criterion R/R ₀ = 1.2. At a critical Re content of Re greater than 6 at%, the toughness of the coating is increased. It is assumed that this increase in toughness is caused by a decrease in the brittle-ductile transition temperature. This leads to an increase in critical strain and a reduction in the occurrence of TTC. An example of this behavior can be seen in Figures 2 through 5. Thus, Figure 2 shows the resistance curve R/R _{0 for} MoRe samples with different Re contents, and Figure 3 shows the resistance curve R/R _{0 for} different MoXRe alloys. The critical strain ε _{k is} significantly increased in each case; this can be similarly seen in Tables 3 and 4. The pattern of cracks can be seen in Figures 4 and 5.

In addition to the increase in critical strain ε _k , a further effect that can be observed is that the pattern of cracking changes from brittle material behavior to ductile material behavior. Typical cracking of ductile material behavior can be seen from the fact that the crack is no longer linear but tends to have a zigzag path. The deflection of the crack at the crack tip is a possible explanation for this cracking behavior. It can be seen in Figure 4b) (MoRe 16.7 at%); in the case of MoRe 16.7 at%, the cracks are indeed much parallel but no longer straight. A tough crack pattern can be clearly seen in Figure 4c) (MoRe 27.9 at%). Although the crack with the tougher characteristics often passes through the entire thickness of the layer, it is not necessarily the entire width of the sample, and as a result, the material maintains an electrically conductive connection. The gradient of the R/R ₀ curve is lower in this case (the curve rises less quickly), as can be seen from the MoRe of Figure 2 and the MoCrRe and MoWRe examples of Figure 3.

Above the critical Re content of the refractory metal based coating, the critical strain ε _{k is} thus significantly increased and the occurrence of cracking is reduced. When the Re content is further increased, the cracking behavior changes from brittleness to toughness. The Re content when the cracking behavior changes depends on the reference material (Mo, MoX) and the alloying element X (Cr, Nb, Ta, Ti, W).

The tough behavior of Mo and MoX coating (X=Cr, Nb, Ta, Ti, W) and MoRe and MoXRe coating (X=Cr, Nb, Ta, Ti, W) can also be achieved by increasing the test temperature. . This effect (brittle-to-tough transition temperature) is appropriately known from the fact that the material extends in all three directions in space. For example, an electron micrograph of the cracked network of Mo coated after tensile testing at 25 ° C and 340 ° C is shown in FIG. Samples tested at 25 °C clearly showed brittle behavior, while samples tested at 340 °C showed tougher behavior. However, such high temperatures are not practical in use and this effect is therefore irrelevant.

It is assumed that the mechanical properties of the coated coating can be further optimized. The coated microstructure and intrinsic stress state deposited based on the refractory metal may be further optimized by the target heat treatment. The target setting of the deposition conditions can also affect the growth of the coating in a targeted manner and is likely to achieve a further increase in toughness.

The tough behavior of Mo and MoX coating (X=Cr, Nb, Ta, Ti, W) and MoRe and MoXRe coating (X=Cr, Nb, Ta, Ti, W) can also be achieved by a smaller layer thickness And reached. For example, the resistance curves R/R ₀ of Mo and MoRe samples having different layer thicknesses of 50 nm and 200 nm are shown in FIG. The R/R ₀ curve with a 50 nm thick coated sample has shifted significantly to the right in the direction of higher strain and the curve has a lower gradient. Therefore, significant improvement in coating toughness can be achieved by reducing the layer thickness.

<Example 2>

In many experiments, different metallic coatings based on refractory metals were deposited on a polyimide substrate. Here, tungsten-based coating is made in the WRe system with different chemical compositions.

In the first series of experiments, WRe coating was produced using the same deposition parameters as in Example 1. Since the sputtering behavior of W and Re is greatly different, very little Re may be introduced into the deposited coating under the deposition conditions used. For example, containing only about 1.3 atomic % Re The WRe coating may be deposited from a tungsten target comprising 15 atomic % Re. Modifying the deposition parameters (for example, using helium instead of argon as the sputtering gas) can increase the Re content of the coating.

Compared to pure tungsten coating, WRe coating showed a significant improvement in toughness in tensile testing similar to MoRe coating.

Figures 9a) to j) show various specific aspects of the coated elastomeric component (1) according to the invention. Each of the specific aspects has an elastic substrate (2) and at least one metallic coating (3) based on the refractory metal. The specific aspect shown in Figures 9b) to j) additionally has at least one conductive track structure (4). The refractory metal based coating (3) need not be part of the conductive rail structure (4) as shown in Figures 9c) and d). However, in a preferred embodiment, the refractory metal based coating (3) is a partial conductive rail structure (4) as shown in Figures 9e) to j). At least one of the conductive track structures may additionally have a metal layer (5), see Figures 9d) and h) to j). In a preferred embodiment, the refractory metal based coating (3) is arranged between the elastic substrate (2) and the metal layer (5) as shown in Figures 9h) to j).

The coated elastomeric component (1) may additionally have at least one half of the guiding layer (6), see Figure 9j).

1‧‧‧coated elastomeric components

2‧‧‧Flexible substrate

3‧‧‧Metal coating based on refractory metal

4‧‧‧ Conductor rail structure

5‧‧‧metal layer

6‧‧‧ semi-conductive layer

Figure 1: Schematic representation of a uniaxial tensile test for electrical resistance measurement that determines the critical fracture strain ε _k . L _constant refers to the length of the fixed clamp in which elongation does not occur.

Figure 2: R/R ₀ curve of Mo and MoRe alloy as a function of the Re content of the coating. The curve referred to by "theory" shows that the increase in resistance is only due to the change in shape of the sample.

Figure 3: R/R ₀ curves for all examined MoX and MoXRe alloys (X = Cr, Nb, Ta, Ti, W).

Figure 4: Optical micrograph of a crack pattern after Mo coating and various MoRe coatings at 15% maximum strain (similar behavior is also shown by MoCr compared to MoCrRe and MoW compared to MoWRe).

Figure 5: Optical micrograph of the crack pattern of MoNb and MoNbRe after 15% maximum strain (similar behavior is also shown by MoTa compared to MoTaRe and MoTi compared to MoTiRe)

Figure 6: Measurement of the ε _{k of} different Re contents (from the failure criterion R/R ₀ = 1.2) as a function of the Re content of the MoRe coating.

Figure 7: Electron micrograph of a crack pattern after Mo coating at 25 ° C and 340 ° C tensile stress, 15% maximum strain.

Figure 8: R/R ₀ curve of Mo and MoRe alloy as a function of coating Re content and layer thickness.

Figure 9: shows various specific aspects of the coated elastomeric component in accordance with the present invention.

Claims (17)

A coated elastomeric component (1), in particular a coated elastomeric electronic component, comprising: an elastic substrate (2), at least one metallic coating based on refractory metal (3), characterized in that The coating (3) of the refractory metal contains more than 6 at% and less than 50 at% of ruthenium (Re). The coated elastic component (1) according to claim 1 of the patent application, wherein the refractory metal-based coating (3) comprises more than 6 at% and less than 35 at% Re. The coated elastic component (1) according to claim 1 or 2, wherein the refractory metal-based coating (3) has a thickness of less than 1 μm, preferably from 5 to 300 nm. The coated elastomeric component (1) according to any of the preceding claims, wherein the refractory metal-based coating (3) is a molybdenum-based coating. The coated elastic component (1) according to any one of the preceding claims, wherein the elastic substrate (2) is transparent. The coated elastic component (1) according to any one of the preceding claims, wherein the elastic substrate (2) comprises at least one of the group consisting of a polymer, a thin glass, a metal foil, and a mineral material. a material. The coated elastic component (1) according to any one of the preceding claims, wherein the refractory metal-based coating (3) has a resistance R pair at which the elastic strain ε of 2% has a resistance R ₀ to be measured. The ratio (R/R ₀ ) is less than 1.2. The coated elastic component (1) according to any one of the preceding claims, wherein the coated The elastic component (1) of the cloth has at least one conductive track structure (4). The coated elastic component (1) according to claim 8 wherein the at least one conductive rail structure (4) has at least one metal layer (5) composed of Cu, Al, Ag, Cu-based alloy, It consists of an Al-based alloy or an Ag-based alloy. The coated elastic component (1) according to claim 8 or 9, wherein the refractory metal-based coating (3) is part of the at least one conductive rail structure (4). The coated elastic component (1) according to claim 9 or 10, wherein the refractory metal-based coating (3) is arranged on the elastic substrate (2) and from Cu, Al, Ag, Cu-based Between the metal layer (5) composed of an alloy, an Al-based alloy or an Ag-based alloy. The coated elastic component (1) according to any one of claims 8 to 11, wherein the coated elastic component (1) additionally comprises at least one half of the conductive layer (6). The coated elastic component (1) according to any one of claims 8 to 12, wherein the refractory metal-based coating (3) is a partial thin film transistor (TFT) structure. The coated elastic component (1) according to any one of the preceding claims, wherein the coated elastic component (1) is derived from an elastic liquid crystal display (LCD), an elastic organic light emitting diode (OLED) a component in a group consisting of a display, an elastic electrophoretic display (electronic paper), an elastic solar cell, an electrochromic elastic film, and an elastic thin film battery. A method of producing a coated component (1), in particular a coated elastomeric electronic component, the method comprising at least the steps of: providing an elastic substrate (2); depositing at least one metallic property based on a refractory metal Coating (3), characterized in that the refractory metal-based coating (3) comprises more than 6 at% and less than 50 at% of Re, and the elastic group is coated Board (2). The method of claim 15, wherein the depositing of the at least one metallic coating based on the refractory metal is carried out by a physical vapor deposition (PVD) process, in particular a sputtering process. The method of claim 15 or 16, wherein the method additionally comprises the step of providing a target based on a refractory metal and comprising from 6 atomic % to less than 50 atomic % Re.