Component with one or more electrically conductive patterns for an electrical, radio or electronic device, and device comprising such a component

Abstract

The invention relates to a component (1) for an electrical, radio or electronic device, the component comprising a substrate (3) provided with a dielectric surface (4) bearing an electrically conductive pattern (5) that has an inner surface in contact with the dielectric surface (4) and an opposing outer surface (5B), the electrically conductive pattern being made of metal, the upper surface of the electrically conductive pattern having a roughness Sa that is lower than or equal to 500 nm, the electrically conductive pattern having a thickness (e) of between 10 nm and 500 nm and a sheet resistance that is lower than or equal to 800 mΩ / □. The invention further relates to an electrical, radio or electronic device comprising such a component. - Components with electrically conductive patterns; electrical, radio or electronic devices with components having electrically conductive patterns.

Description

[0001] COMPONENT WITH ELECTROCONDUCTIVE PATTERN(S) FOR ELECTRICAL, RADIO-ELECTRIC OR ELECTRONIC DEVICE, AND DEVICE COMPRISING SUCH A COMPONENT

[0002] TECHNICAL FIELD

[0003] The present invention relates to the general technical field of components for electrical, radioelectric or electronic devices, such as in particular for radioelectric devices transmitting and / or receiving radiofrequency waves or for sensors / detectors, comprising a substrate provided with a dielectric surface carrying at least one electrically conductive pattern.

[0004] The invention relates more specifically to a component for an electrical, radioelectric or electronic device, comprising a substrate provided with a dielectric surface carrying at least one electrically conductive pattern, said electrically conductive pattern having a lower surface in contact with said dielectric surface and an opposite upper surface. The invention further relates to an electrical, radioelectric or electronic device comprising such a component.

[0005] PRIOR TECHNIQUE

[0006] In the field of components for electrical, radioelectric or electronic devices with electroconductive pattern(s), components manufactured using so-called "printed electronics" techniques have been known for several years, which consist of producing electroconductive patterns on the surface of a substrate by printing (using an inkjet technique or screen printing, for example) using a conductive ink or paste. These conductive inks or pastes typically comprise a polymeric liquid or pasty phase, in which particles of an electroconductive material are dispersed. After printing, the deposited ink or paste is subjected to a drying / hardening step to form electroconductive patterns with a polymer matrix within which the particles of electroconductive material are trapped, ensuring the electroconductive nature of the patterns formed.Among the devices incorporating such a component, radiofrequency antennas are thus known in particular, such as for example RFID radio tags, the radiating antenna element of which is formed by an electroconductive pattern printed on a dielectric substrate in accordance with the above. While such known devices and components are generally satisfactory, they nevertheless remain perfectible in terms of controlling the electrical conductivity properties of their printed electroconductive patterns and, hence, in terms of the level of radioelectric performance, and this in particular for applications in radiofrequency wave domains ranging from ultra-high frequencies (UHF) to Terahertz (THz) frequencies.

[0007] Furthermore, known devices and components sometimes lack reliability and durability, the properties of their printed electrically conductive patterns tending to degrade over time, due to aging of the polymer matrix of the patterns, migration of the particles of electrically conductive material, etc. This can notably lead to an undesirable variation in the properties of the electrically conductive patterns depending on environmental variables (humidity, temperature, etc.). In addition, while the introduction of printed electronics techniques has led to advances in reducing manufacturing costs, reducing weight and facilitating component integration, progress still remains to be made in this area. In particular, the conductive inks used are still generally relatively expensive, and the patterns must be printed at relatively large thicknesses in order to obtain sufficient electrical conductivity.

[0008] STATEMENT OF THE INVENTION

[0009] The objects assigned to the invention therefore aim to provide a response to the aforementioned problems and needs, and to propose in particular a new component with electro-conductive pattern(s) for an electrical, radioelectric or electronic device, the electro-conductive pattern(s) of which has / have excellent electrical properties, in particular suitable for the manufacture of radioelectric devices operating in very high radiofrequency wave domains or for electronic devices of the sensor type. Another object of the invention aims to propose a new component for an electrical, radioelectric or electronic device which, while having excellent electrical properties, is particularly compact and easy to integrate.

[0010] Another object of the invention is to propose a new component for an electrical, radioelectric or electronic device which, while having excellent electrical properties, is particularly inexpensive to manufacture.

[0011] Another object of the invention is to propose a new component for an electrical, radioelectric or electronic device which, while having excellent electrical properties, is particularly durable and reliable.

[0012] Another object of the invention aims to propose a new electrical, radioelectric or electronic device comprising a component with electrically conductive pattern(s) whose electrical, radioelectric or electronic operation is particularly efficient.

[0013] Another object of the invention aims to propose a new electrical, radioelectric or electronic device comprising a component with electrically conductive pattern(s) which is compact and easy to integrate.

[0014] Another object of the invention is to propose a new electrical, radioelectric or electronic device comprising a component with electrically conductive pattern(s) which is inexpensive to manufacture.

[0015] Another object of the invention is to propose a new electrical, radioelectric or electronic device comprising a component with electrically conductive pattern(s) which is durable and reliable.

[0016] Another object of the invention is to propose a new radioelectric device, such as a radiofrequency wave transmitter and / or receiver device, the radiofrequency antenna radiating element of which has a particularly high quality factor and radiation efficiency. Another object of the invention is to propose a new electronic device constituting a sensor / detector having excellent measurement resolution.

[0017] The objects assigned to the invention are achieved using a component for an electrical, radioelectric or electronic device, comprising a substrate provided with a dielectric surface carrying at least one electroconductive pattern, said electroconductive pattern having a lower surface in contact with said dielectric surface and an opposite upper surface, said component being characterized in that said electroconductive pattern is made of metal, the upper surface of the electroconductive pattern having a roughness Sa which is less than or equal to 500 nm, said electroconductive pattern having a thickness of between 10 nm and 500 nm.

[0018] The objects assigned to the invention are further achieved using an electrical, radioelectric or electronic device comprising such a component.

[0019] SUMMARY DESCRIPTION OF THE DRAWINGS

[0020] Other features and advantages of the invention will appear and emerge in more detail on reading the description given below, with reference to the appended drawings, given solely as illustrative and non-limiting examples, among which:

[0021] - figure 1 schematically illustrates, in a sectional view, an example of a component in accordance with the invention;

[0022] - figure 2 schematically illustrates, in a sectional view, another example of a component in accordance with the invention;

[0023] - the figure illustrates an example of a radioelectric device according to the invention, which constitutes a three-dimensional radio frequency identification (RFID) system radio tag, the electroconductive pattern forming a radiating element of an RFID radio frequency antenna;

[0024] - Figure 4 illustrates an example of a component for a radioelectric device according to the invention, the electroconductive patterns of which form a radiating element of a WiFi® dipole radiofrequency antenna; - Figure 5 illustrates an example of a component for an electronic device of the capacitive sensor type, the electroconductive patterns of which form capacitive sensor electrodes;

[0025] - Figure 6 illustrates an example of an electrical device according to the invention, which constitutes an electrical heating device, forming a heating / defrosting radome for a radiodetermination system (proximity radar sensor), the electrically conductive pattern of which forms a heating circuit.

[0026] BEST WAY TO CARRY OUT THE INVENTION

[0027] The invention relates firstly to a component 1 for an electrical, radioelectric or electronic device 2, i.e. a functional element or subassembly intended to be integrated into an electrical, radioelectric or electronic device 2 to ensure (or at least contribute to ensuring) a particular electrical, radioelectric or electronic function. The component 1 comprises a substrate 3 provided, directly or indirectly, with a dielectric surface 4 carrying at least one electrically conductive pattern 5. Said substrate 3 therefore forms a support for said electrically conductive pattern 5. By "dielectric surface" is meant here advantageously a non-electroconductive surface, i.e. an electrically insulating surface, and in particular a non-metallic surface.By "electroconductive pattern" is meant here generally a layer of an electroconductive material adhering to the dielectric surface 4 and having a particular, singular shape, chosen in consideration of the electrical, radioelectric or electronic function of the device 2 in which the component 1 is intended to participate. Examples of a component 1 according to the invention are illustrated schematically in figures 1 and 2. The invention further relates, as such, to an electrical, radioelectric or electronic device 2 comprising such a component 1.

[0028] As schematically illustrated in Figures 1 and 2, the electrically conductive pattern 5 has a lower surface 5A in contact with the dielectric surface 4 and an opposite upper surface 5B. Advantageously, as schematically illustrated in Figures 1 and 2, the upper surface 5B of the electrically conductive pattern 5 is not in contact with said dielectric surface 4, but preferably extends above said dielectric surface 4. According to a variant illustrated in Figure 1, the electrically conductive pattern 5 is arranged in direct contact with a surface of the substrate 3. In this case, said substrate 3 is made of dielectric material, and the surface of the substrate 3 therefore directly forms said dielectric surface 4. According to another variant illustrated in Figure 2, a surface of the substrate 3 is covered with an intermediate coating 6, such as for example a layer of varnish or a primer layer, forming said dielectric surface 4 provided with said electrically conductive pattern 5.The intermediate coating 6 is therefore then made of a dielectric material, and has a lower surface adhering to the surface of the substrate 3 and an opposite upper surface, which then advantageously forms the dielectric surface 4 carrying the electroconductive pattern δ. In such a variant, the substrate 3 may possibly not itself be made of dielectric material 4, although it is however preferable that it is.

[0029] Preferably, the substrate 3 is made of polymer material, composite or hybrid material with a polymer matrix, paper, glass, textile, leather (animal leather (skin), vegetable or even synthetic) or ceramic material. It remains possible, however, although less preferably, for the substrate 3 to be made of a metallic, non-dielectric material, in the event that the surface of the substrate 3 is covered with an intermediate coating 6, as envisaged above, which is itself made of a dielectric material so that this intermediate coating 6 forms a dielectric surface 4 in contact with which the electroconductive pattern 5 is arranged.

[0030] According to the invention, the electroconductive pattern 5 carried by the substrate 3 is made of metal, that is to say that the electroconductive pattern δ is therefore formed, apart from possible non-metallic impurities, of at least one elementary metal (or “elementary simple body”), of at least one mixture of elementary metals, or even of at least one metal alloy. In other words, the electroconductive pattern 5 is made of solid metal, and thus forms a continuous layer of metal. In addition, the upper surface 5B of the electroconductive pattern 5 of the component 1 according to the invention has a roughness Sa which is less than or equal to 500 nm. The “roughness Sa” (or “roughness parameter Sa”) is the extension of the roughness parameter Ra (“roughness Ra” or “Arithmetic Average Roughness”, relating to a profile) to a surface, so that it therefore makes it possible to evaluate, to characterize the arithmetic average roughness of a surface.The “roughness Sa”, and the means and methods for measuring the latter, are defined in particular in the ISO 25178:2016 standard. For example, the roughness Sa can be measured using an atomic force microscope, by interferometry, or even using a confocal probe. Furthermore, the electrically conductive pattern 5 of the component 1 according to the invention has a thickness e which is between 10 nm and 500 nm.

[0031] It has indeed been observed that, interestingly, the particular combination of the above-mentioned characteristics in terms of the constitution of the electroconductive pattern 5, the roughness Sa of the upper surface 5B and the thickness e of the latter gives the component 1 according to the invention excellent electrical properties, in particular in terms of the homogeneity of the conductivity / resistivity properties of the electroconductive pattern 5. In addition, the fact that the electroconductive pattern 5 is made of metal and that the upper surface 5B of the latter has a roughness Sa of less than or equal to 500 nm makes it possible to give the upper surface 5B a high surface conduction and a particularly smooth character, which makes it possible to minimize conduction losses. Furthermore, the fineness of the electroconductive pattern 5 allows the design of a particularly compact and easily integrated component, and having a particularly low material cost.

[0032] In addition to allowing a particularly low thickness e of the electroconductive pattern 5, the fact that the electroconductive pattern 5 is made of metal (“or solid metal”), and not in the form of a composite material with a polymer matrix in which electroconductive particles such as, for example, metal particles are dispersed, as in the case of conventional printed electronics, advantageously gives the electroconductive pattern 5 great durability and great reliability over time, its electrical conductivity / resistivity properties not varying significantly over time.

[0033] The component 1 according to the invention thus allows in particular the manufacture of a radioelectric device 2, such as a device for transmitting and / or receiving radiofrequency waves, in which the conductive pattern 5 of the component 1 forms a radiating element of a radiofrequency antenna, having a particularly high quality factor and radiation efficiency, in particular for an application in the fields of High Frequency (HF), Very High Frequency (VHF), Ultra High Frequency (UHF), Super High Frequency (SHF), Extremely High Frequency (EHF) or even in the Tera-Hertz (THz) frequency range. The component 1 according to the invention also allows the manufacture of an electronic device 2 constituting a sensor / detector, in which the electroconductive pattern 5 of the component 1 forms a sensor / detector electrode, having excellent measurement resolution / sensitivity.

[0034] Obviously, the invention is not limited to these particular examples of devices 2, and other types of electrical, radioelectric or electronic devices may advantageously benefit from the integration of a component 1 with electroconductive pattern(s) 5 according to the invention. For example, as will be described later, the component 1 of the invention may advantageously be integrated into an electrical device 2 in which the electroconductive pattern 5 forms a heating circuit, to form a particularly efficient electrical heating device.

[0035] Even more advantageously, the roughness Sa of the upper surface 5B of the electroconductive pattern 5 is less than or equal to 300 nm, preferably less than or equal to 200 nm, preferably less than or equal to 100 nm, preferably less than or equal to 50 nm, preferably less than or equal to 20 nm, and more preferably less than or equal to 15 nm. Thus, the level of conduction loss at the upper surface 5B of the electroconductive pattern 5 is particularly low and well controlled.

[0036] Advantageously, the upper surface 5B of the electroconductive pattern 5 of the component 1 further has a roughness Ra which is less than or equal to 500 nm, preferably less than or equal to 300 nm, preferably less than or equal to 200 nm, preferably less than or equal to 100 nm, preferably less than or equal to 50 nm, preferably less than or equal to 20 nm, and more preferably less than or equal to 15 nm.

[0037] Furthermore, it is also advantageous, for the reasons mentioned above and in particular for radio applications, that the lower surface 5A of the electroconductive pattern 5 also has a very low roughness. As such, the lower surface 5A of the electroconductive pattern 5 of the component 1 thus preferably has a roughness Sa which is less than or equal to 500 nm. More preferably, the roughness Sa of the lower surface 5A of the electroconductive pattern 5 is less than or equal to 300 nm, preferably less than or equal to 200 nm, preferably less than or equal to 100 nm, preferably less than or equal to 50 nm, preferably less than or equal to 20 nm, and more preferably less than or equal to 15 nm.Advantageously, the lower surface 5A of the electroconductive pattern 5 of the component 1 further has a roughness Ra which is less than or equal to 500 nm, preferably less than or equal to 300 nm, preferably less than or equal to 200 nm, preferably less than or equal to 100 nm, preferably less than or equal to 50 nm, preferably less than or equal to 20 nm, and more preferably less than or equal to 15 nm.

[0038] Preferably, while being greater than 10 nm, the thickness e of the electroconductive pattern 5 is less than or equal to 400 nm, preferably less than or equal to 300 nm, and more preferably less than or equal to 200 nm. Such fineness of the electroconductive pattern 5 further contributes to the particularly compact, and therefore easily integrated, nature of the component 1. It also allows excellent control of the manufacturing cost, as well as a reduction of the environmental impact of the component 1, by limiting the quantity of metal contained in the component 1. In addition, depending on the metal of the electroconductive pattern 5, such fineness of the electroconductive pattern 5 can make it possible to give the latter a certain transparency in the range of the visible to the human eye.

[0039] According to one variant, the thickness e of the electroconductive pattern(s) 5 is substantially constant over the entire extent of the electroconductive pattern(s) 5, i.e. the thickness e is substantially identical at every point of the electroconductive pattern(s) 5 (figures 1 and 2). According to another variant, the component 1 may have a plurality of electroconductive patterns 5 whose respective thickness e, substantially constant, is different from one electroconductive pattern 5 to another.According to another variant, the thickness e of the electroconductive pattern(s) 5 is variable, that is to say that the electroconductive pattern(s) 5 has at least a first zone and a second zone, distinct, the thickness e of the electroconductive pattern(s) 5 being increasing or on the contrary decreasing (thickness gradient) from said first zone towards said second zone, the value of the roughness Sa of the upper surface 5B of the electroconductive pattern(s) 5 remaining within the aforementioned ranges of values.Such a difference in thickness e of the electroconductive pattern(s) 5, in the ranges of values ​​indicated previously, thus advantageously makes it possible to create electroconductive zones of different conductivity or resistivity, or even of different transparency or reflectivity to electromagnetic waves, which may be of particular interest for certain applications of the component 1 and of the electroconductive pattern(s) 5 that it comprises. For example, for a component 1 of a radioelectric device, this may make it possible to create a variation in the wave shielding / reflectivity properties for a metasurface. According to another example, when the electroconductive pattern(s) 5 form(s) a heating circuit for an electrical heating device, this makes it possible to generate zones of the heating circuit offering different heating intensities when the heating circuit is electrically powered.

[0040] Advantageously, the metal of the electroconductive pattern 5 is chosen from the group comprising: silver Ag, nickel Ni, gold Au, copper Cu, aluminum Al, iron Fe and tin Sn and their alloys. In particular, as examples of nickel alloys, mention may be made of nickel-boron Ni-B, nickel-phosphorus Ni-P, or nickel-gold Ni-Au alloys. Even more advantageously, said electroconductive pattern 5 is formed, apart from impurities, from a (single) elemental metal which is silver Ag, taking into account the excellent intrinsic electrical properties that the latter presents compared to other conceivable metals.

[0041] Preferably, the metal of the electrically conductive pattern 5 is more than 90% pure, preferably more than 95% pure, and more preferably more than 98% pure. The electrically conductive pattern 5 can thus advantageously be formed of silver Ag that is more than 90% pure, preferably more than 95% pure, and more preferably more than 98% pure. Such a level of purity of the metal contributes in particular to the excellent electrical properties of the electrically conductive pattern 5. Furthermore, in the case where the component 1 is intended to be used in an electronic device constituting a sensor, in which the electrically conductive pattern 5 forms a sensor electrode, such a level of purity makes it possible to limit the risk of the presence of chemical element(s) potentially incompatible with a sensitive sensor element (electronic component, detection chemical substance, etc.) which could be arranged in contact with the electrode formed by the electrically conductive pattern 5.This avoids the risk of degradation or premature aging of the sensor. Advantageously, the electrically conductive pattern 5 of the component 1 preferably has an electrical conductivity which is greater than or equal to 25.10. 6 S / m (siemens per meter), preferably greater than or equal to 35.10 6 S / m, and preferably still greater than or equal to 45.10 6 S / m.

[0042] The electroconductive pattern 5 of the component 1 advantageously has a sheet resistance (Rs) which is less than or equal to 800 mQ / n (ohm per square), preferably less than or equal to 500 mQ / n (ohm per square), preferably less than or equal to 300 mQ / n (ohm per square), preferably less than or equal to 100 mQ / n, and more preferably less than or equal to 40 mQ / n. Typically, the sheet resistance Rs can be measured by the four-point method, for example using a PRO4 4-point measuring system marketed by the company MICROWORLD®. In a known manner, the four-point method makes it possible to characterize the resistivity of metallic films or thin layers at room temperature.It consists of placing four aligned and equidistant electrodes (or "tips") in contact with the surface to be analyzed, two of the electrodes being used to inject an electric current of known value between two points on the surface, the other two electrodes being used to measure the induced potential difference. The combination of a low roughness Sa, as mentioned above, of the upper surface 5B of the electroconductive pattern 5 and such a preferential value of sheet resistance Rs makes it possible to further limit the conduction losses of the electroconductive pattern 5, and therefore to give the component 1 even better performance. In practice, the value of the sheet resistance Rs of the electroconductive pattern 5 may depend on the thickness e of the electroconductive pattern 5.Thus, according to one example, the electroconductive pattern 5 of the component 1 is formed of silver Ag that is more than 90% pure, preferably more than 95% pure, and more preferably more than 98% pure, with a thickness e of 500 nm and has a sheet resistance Rs of approximately 40 mΩ / n. According to another example, the electroconductive pattern 5 is formed of silver Ag that is more than 90% pure, preferably more than 95% pure, and more preferably more than 98% pure, with a thickness e of 50 nm and has a sheet resistance Rs of approximately 800 mΩ / n.

[0043] Preferably, said at least one electroconductive pattern 5 has a resolution which is less than or equal to 100 pm, preferably less than or equal to 50 pm, preferably less than or equal to 20 pm, preferably less than or equal to 1 pm. Advantageously, the resolution of the electroconductive pattern 5 corresponds to a minimum width (for example a minimum line width) of the electroconductive pattern 5 (considered in a plane parallel to a mean extension plane of the dielectric surface 4) and / or to a minimum distance (or interval) between two electroconductive patterns 5 or between two parts of the same electroconductive pattern 5. Such precision of definition of the electroconductive pattern(s) 5 of the component 1 further improves the electrical performance of the latter.In particular, in the case where the electroconductive pattern 5 of the component 1 forms a radiofrequency antenna radiating element, such a resolution makes it possible to obtain a particularly high quality factor, which is favorable to use of the component 1 in a radio device 2 intended to operate in radiofrequency ranges from high frequencies (HF) to Tera-Hertz (THz) frequencies. In the case where the electroconductive pattern 5 of the component 1 forms a sensor electrode, such a resolution of the electroconductive pattern 5 contributes in particular to excellent measurement / detection accuracy.In other applications of the component 1, and for example in the case where the electroconductive pattern(s) 5 form(s) a heating circuit for an electrical heating device 2, the electroconductive pattern(s) 5 may thus have a particularly small width, limiting the impact of the electroconductive pattern(s) 5 on the transparency of the substrate 3. Typically, the resolution of the electroconductive pattern 5 may be measured using a digital microscope, such as for example an RH-2000 digital microscope from the company HIROX®.

[0044] Advantageously, depending on the material and the electrical, radioelectric or electronic application considered, the substrate 3 has a thickness of between 8 μm and 15 mm, and even more advantageously of between 25 μm and 10 mm. Where appropriate, the intermediate coating 6 has a thickness preferably of between 5 nm and 100 μm, and even more preferably of between 15 nm and 20 μm. These dimensional characteristics advantageously contribute to giving the component 1 a compact and easily integrated character, without prejudice to the performance of the latter in terms of electrical conductivity / resistivity.

[0045] Depending on the intended applications of the component 1, the substrate 3 (as well as the intermediate coating 6, if applicable) may be transparent (for example, in a wavelength range in the visible range for the human eye, and / or in one or more specific electromagnetic wavelength ranges) or, on the contrary, opaque. Depending on the intended applications of the component 1, the substrate 3 (as well as the intermediate coating 6, if applicable) may be flexible, i.e. it may advantageously be curved, folded, by human force alone without breaking, deforming, or irreversibly degrading. Such a flexible character may advantageously contribute to the integrability of the component 1. Alternatively, the substrate s may, on the contrary, be substantially rigid, so that it cannot be curved, folded, by human force alone without breaking, deforming, or irreversibly degrading.Such a flexible character can advantageously contribute to the robustness of component 1.

[0046] According to a variant, the substrate 3 of the component 1, as well as preferably the electroconductive pattern 5 carried by the latter, has(have) a three-dimensional shape. By "three-dimensional shape", it is advantageously meant that the substrate 3 and the electroconductive pattern 5 form, as such, a physical object which develops substantially in the three dimensions of space, following non-negligible distances from each other. In other words, the substrate 3 of the component 1, as well as preferably the electroconductive pattern 5, are not flat, that is to say substantially two-dimensional with a very small thickness compared to their two other characteristic dimensions. As such, the substrate 3 is preferably a thermoformed substrate, that is to say that its three-dimensional shape results from a step of thermoforming an initially flat thermoformable substrate.

[0047] Optionally, the substrate 3 of the component 1 may be overmolded, typically by injection-molding of a polymer material or a mixture of polymer materials, in order for example to form a protective and / or support structure for the substrate 3 carrying the electroconductive pattern 5, which contributes in particular to the mechanical robustness of the component 1.

[0048] It is conceivable that the substrate 3, of three-dimensional shape or not, is bonded using any adhesive suitable for a separate part, which may possibly form a protective and / or support structure for the substrate 3. Preferably, the component 1 comprises a dielectric upper coating (i.e. non-conductive, electrically insulating) which covers at least the upper surface 5B of said at least one electroconductive pattern 5 carried by the substrate 3, so that the electroconductive pattern 5 thus encapsulated between the substrate 3 (or the intermediate coating 6, if applicable) and said dielectric upper coating. The presence of such a dielectric upper coating gives the component 1 greater robustness and better reliability, by protecting at least the electroconductive pattern 5 against external aggression, in particular mechanical and / or chemical, or against accidental short-circuiting.For example, the dielectric top coating may be formed from a protective varnish layer.

[0049] Optionally, the component 1 comprises at least one electrical connection element 7 secured to the substrate 3, for example by gluing, soldering or crimping, in electrical contact with the electroconductive pattern(s) 5 carried by the latter, to electrically connect the electroconductive pattern(s) 5 of the component 1 to a separate and remote member or means, suitable for the electrical, radioelectric or electronic application (for example an electronic radiofrequency telecommunication module, an electronic signal processing circuit, a power supply circuit, etc.). It is also conceivable that the component 1 is designed and configured so that the electrical connection between the electroconductive pattern(s) 5 of said separate and remote member or means can be achieved by direct surface contact via a connection resumption using a metal blade connector / EMC joint.

[0050] As introduced previously, the invention further relates, as such, to an electrical, radioelectric or electronic device 2 comprising a component 1 according to the invention, as described above. It is therefore an electrical, radioelectric or electronic device 2 comprising a component 1 comprising a substrate 3 provided with a dielectric surface 4 carrying at least one electroconductive pattern 5, said electroconductive pattern 5 having a lower surface 5A in contact with said dielectric surface 4 and an opposite upper surface 5B, which component 1 is component 1 according to that of the invention described above. Thus, the above description of the component 1 according to the invention applies mutatis mutandis to the electrical, radioelectric or electronic device 2 according to the invention.In practice, and as already specified in the above, the invention is not particularly limited in terms of the nature of the electrical, radioelectric or electronic device 2. However, several types of electrical, radioelectric or electronic devices 2 have been identified which can advantageously benefit from the integration of a component 1 in accordance with the invention.

[0051] In particular, according to one embodiment, the device 2 constitutes a radioelectric device, the electroconductive pattern 5 of the component 1 forming a radiating element of a radiofrequency antenna, that is to say an antenna part (sometimes simply designated by the term “antenna”) capable of emitting or receiving radioelectric waves.

[0052] In accordance with what has been described previously in connection with the component 1 according to the invention, the substrate 3 as well as the electroconductive pattern(s) 5, of the component 1 of such a radioelectric device 2 can advantageously have a three-dimensional shape, which can in particular facilitate the integration of the component 1 within the radioelectric device 2.

[0053] Said radioelectric device 2 may comprise an electronic chip s, secured to the substrate 3 of the component 1 in electrical contact with the electroconductive pattern(s) 5 carried by the latter, for example in the case where the radioelectric device 2 constitutes or comprises an RFID radio tag. Alternatively, the radioelectric device 2 may be devoid of such an electronic chip, but comprise a radiofrequency telecommunication electronic module separate and remote from the component 1, which is connected to the electroconductive pattern(s) 5 of the component 1 via an electrical connection element 7 secured to the substrate 3 in electrical contact with the electroconductive pattern(s) 5 and a suitable connection cable 9 connecting the electronic telecommunication module to the electrical connection element 7.For example, the electrical connection element 7 secured to the substrate 3 may be a male or female RF radiofrequency connector of the SMA type (“SubMiniature version A”) or a male or female RF radiofrequency connector of the U.FL or W.FL type manufactured by the company HIROSE®. Optionally, the radioelectric device 2 may further comprise a radiofrequency transmitter and / or receiver (not illustrated) designed and configured to interact remotely by radiofrequency waves with the radiofrequency antenna radiating element (and / or with the electronic chip 8 where applicable) of the radioelectric device 2, with a view to establishing a wireless connection for transmitting information between the radioelectric device 2 and the radiofrequency transmitter and / or receiver.

[0054] Figure 3 illustrates in particular a radio device 2 which constitutes a radio tag for a three-dimensional UHF radio frequency identification system (“Radio Frequency Identification”, RFID), in which the electroconductive pattern 5 forms a radiating element of an RFID radio frequency antenna. The substrate 3 of the component 1 is made of a polycarbonate (PC) sheet with an initial thickness of 250 μm, thermoformed into a half-sphere (“cup”). The radio device 2 comprises an RFID electronic chip 8, in this case a Monza R6 RFID chip marketed by the company IMPINJ®, secured to the substrate 3 using an adhesive, in electrical contact with two adjacent contact zones of the electroconductive pattern 5. Adhering to the surface of the substrate 3, the electroconductive pattern 5, made of pure silver Ag, takes on its hemispherical three-dimensional shape. The thickness e of the electroconductive pattern 5 is approximately 300 nm.The upper surface 5B of the electrically conductive pattern 5 has a roughness Sa of about 20 nm. The electrically conductive pattern 5 has a sheet resistance Rs of about 85 mOhm / n.

[0055] Figure 4 illustrates an example of component 1 for radio device 2, the electroconductive patterns 5 of which form a radiating element of a WiFi® dipole radiofrequency antenna (2.4 GHz), for example for use in the field of the Internet of Things (loD, or loT in English). In this case, the electroconductive patterns 5 define two radiating half-strands and a two-wire feed line. The substrate 3 of the component 1 consists of a polycarbonate (PC) sheet with an initial thickness of 250 μm, thermoformed into a half-sphere. The thickness e of the electroconductive patterns 5 is approximately 300 nm. The upper surface 5B of the electroconductive patterns 5 has a roughness Sa of approximately 20 nm. The electroconductive patterns 5 have a sheet resistance Rs of approximately 85 mOhm / n.In order to allow interconnection with a radiofrequency telecommunications electronic module (not shown), an electrical connection element 7 of the HIROSE® U.FL RF connector type is bonded to the substrate 3 in contact with the two-wire line of the antenna radiating element, using an isotropic conductive adhesive PANACOL Elecolit® 3661. The end of a suitable radiofrequency coaxial cable 9 is connected to the electrical connection element 7, the other end of the cable 9 being intended to be connected to the radiofrequency telecommunications electronic module.

[0056] According to another embodiment, the device 2 constitutes a sensor (or detector), as an electronic device2, said at least one electroconductive pattern 5 of the component 1 then forming at least one sensor or detector electrode. Optionally, a particular chemical detection substance may be present on at least a portion of the upper surface 5B of the electroconductive pattern 5 (chemical sensor). The device 2 may advantageously comprise a suitable electronic measurement circuit connected to the electroconductive pattern 5.

[0057] According to one example, the electroconductive pattern 5 may form a capacitive sensor electrode (or “capacitive electrode”), for example to detect, by measuring one of the capacitance of the electroconductive pattern 5, a contact exerted on the component 1 by a finger of a user or the presence of a substance on the component 1 (for example liquid water or frost). Figure 5 illustrates an example of such a component 1 whose electroconductive patterns 5 form capacitive sensor electrodes. In this example, the substrate 3 is made of a sheet of polyethylene terephthalate (PET) with an initial thickness of 125 μm. The electroconductive patterns 5 are made of pure silver Ag, with a thickness e of approximately 250 nm. The upper surface 5B of the electroconductive patterns 5 have a roughness Sa of approximately 20 nm. The electrically conductive patterns 5 have a sheet resistance Rs of approximately 105 mOhm / n.

[0058] According to another example (not illustrated), the electroconductive pattern(s) 5 may form a resistive sensor electrode (or “resistive electrode”), for example to detect a deformation of the substrate 3 (strain gauge) by measuring a variation in the electrical resistance between two distinct points (and typically between two opposite ends) of the electroconductive pattern 5. Furthermore, in the case where the substrate 3 is made of a material having a relatively high coefficient of thermal expansion, it may thus be possible to indirectly measure a temperature of the substrate 3.According to yet another example (not illustrated), the component 1 may comprise one or more electroconductive patterns 5 forming two electrodes, between which is arranged a sensitive element whose resistive properties may vary depending on environmental conditions (concentration of the surrounding atmosphere in a particular gas, humidity level, temperature, etc.).

[0059] Furthermore, as introduced previously, it has been observed that the component 1 according to the invention can find, in a very interesting manner, an application in an electrical device which is an electrical heating device 2, in which the electrically conductive pattern 5 of the component 1 forms a heating circuit (when an electric current is applied, typically between two ends of the electrically conductive pattern 5). Typically, the heating circuit (or “resistive circuit”) can take the form of one or more wire(s), one or more grid(s) and / or one or more electrically conductive coil(s). Advantageously, the component 1 can comprise two electrical connection elements 7, for example two bus bars, secured to the substrate 3 in electrical contact with the electrically conductive pattern(s) 5.The electrical heating device 2 can advantageously comprise a control and electrical power supply circuit, connected to said electrical connection elements 7.

[0060] As an example, Figure 6 illustrates an electrical heating device 2 forming a heating / defrosting radome for a radiodetermination system (proximity radar sensor), comprising an XM132 radar sensor module manufactured by the company ACCONEER, operating at 60 GHz. The component 1 of the electrical heating device 2 comprises a substrate 3 made of a polycarbonate (PC) sheet with an initial thickness of 250 μm, thermoformed. The electroconductive pattern 5, made of pure silver Ag, forms a grid. To ensure transparency of the radome to the radar waves of the radar sensor module, the grid has meshes 200 μm wide and 5,000 μm in aperture. The electroconductive pattern 5 has a thickness e of 120 nm. The upper surface 5B of the electroconductive pattern 5 has a roughness Sa of approximately 20 nm. The electrically conductive pattern 5 has a sheet resistance Rs of approximately 250 mOhm / n.When the electrically conductive pattern 5 is connected to a direct current power supply and control circuit (voltage of approximately 25 V at a current of approximately 1.4 A), it is possible to dissipate more than 35 W over a surface area of ​​0.05 m. 2 (i.e. a power greater than 600 W / m 2) and to reach a surface temperature of the component 1 of more than 60°C after 1 min of heating. By way of illustrative and non-limiting example, different steps of a method for manufacturing a component 1 according to the invention will be described below. According to this method, the electroconductive pattern(s) 5 made of metal are manufactured by selective metallization of a previously masked substrate, according to a technique of non-electrolytic chemical deposition of metal on the surface of the substrate by projection, in the form of one or more aerosols, of one or more metallization solution(s) containing at least one metal in the form of a metal cation (oxidant) and at least one reducing agent capable of transforming the metal cation into metal.

[0061] This method advantageously makes it possible to obtain a component 1 in accordance with the invention in a particularly simple, rapid and efficient manner. The examples of component 1 described above in connection with figures 3 to 6 were obtained using such a method.

[0062] Step A of providing a substrate

[0063] Advantageously, the substrate 3 is chosen from a dielectric material, preferably a polymer material or a polymer matrix composite material. To obtain a component 1 whose substrate 3 has a three-dimensional shape, it is preferable for the substrate to initially be in a flat shape (flat substrate), typically with a thickness of between 8 μm and 15 mm, and for the material of the substrate 3 to be chosen to be thermoformable. Among the thermoformable polymer materials that can be considered, non-limiting examples may be mentioned polystyrene (PS), high-impact polystyrene (SB / HIPS), polyethylene (PE), polypropylene (PP), polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), or thermoplastic polyesters, such as, for example, polylactic acid (PLA), polyethylene terephthalate (PET) and polyethylene terephthalate glycol (PETG).To obtain a component 1 whose substrate 3 is substantially flat, the material of the substrate 3 may advantageously be chosen from the thermoformable polymer materials listed above or from the following examples of thermosetting polymer materials: polyimides, thermosetting polyesters, phenolic resins and epoxies. Furthermore, it proves advantageous in terms of ease of obtaining the roughness levels Sa of the electroconductive pattern(s) 5 mentioned above, that the substrate 3 chosen itself has an upper surface, intended to carry the electroconductive pattern(s) 5, the roughness Sa of which is less than or equal to 500 nm, preferably less than or equal to 300 nm, preferably less than or equal to 200 nm, preferably less than or equal to 100 nm, preferably less than or equal to 50 nm, preferably less than or equal to 20 nm, and more preferably less than or equal to 15 nm.

[0064] Possible step B of preparation of the substrate surface

[0065] The method may comprise a step B of preparing the surface of the substrate in order to facilitate the performance and / or increase the efficiency of the following steps of the method. Step B may comprise an operation of cleaning and / or degreasing the surface of the substrate, using any products known per se and suitable. In addition to or instead of such a cleaning / degreasing operation, step B may comprise an operation of depositing on the surface of the substrate an intermediate coating 6 made of a dielectric material, such as a layer of varnish, for example a layer of a UV-curing varnish applied by spraying, by any known and suitable means such as a compressed air paint gun (for example, a High Volume Low Pressure (HVLP) spray gun). In this case, an upper surface of the intermediate coating 6 will form a dielectric surface 4 with which the substrate 3 will be provided.The implementation of such an intermediate coating 6 may possibly make it possible to give the dielectric surface 4 a roughness Sa which is less than or equal to 500 nm, preferably less than or equal to 300 nm, preferably less than or equal to 200 nm, preferably less than or equal to 100 nm, preferably less than or equal to 50 nm, preferably less than or equal to 20 nm, and more preferably less than or equal to 15 nm, by “smoothing” the underlying surface of the substrate 3. Alternatively or in addition, step B may comprise a physical and / or chemical treatment operation for reducing the roughness Sa of the surface of the substrate 3, for example by sandblasting or shot blasting, to achieve the above-mentioned preferred value ranges. Step C of forming a temporary masking coating.

[0066] In order to allow selective metallization of the substrate 3 to produce the desired electroconductive metal pattern(s), the method comprises an operation of forming a temporary masking coating, which adheres to the dielectric surface 4 with which the substrate 3 is provided, to obtain a masked substrate having at least one unmasked zone, and thus selectively delimit one or more particular zone(s) of the dielectric surface 4 which will carry the electroconductive pattern(s) 5.

[0067] Advantageously, step C is carried out by selective deposition, or by non-selective deposition followed by selective ablation / removal, of a layer of a liquid or pasty masking composition on the dielectric surface 4 of the substrate 3. The deposition of the masking composition may optionally be followed by drying and / or hardening of the deposited masking composition. Depending on the formulation of the masking composition chosen, the drying and / or hardening of the latter may comprise drying / desolvation, optionally under the effect of a thermal input, or polymerization / crosslinking of the deposited masking composition under the effect of a thermal input and / or under the action of actinic radiation (for example, by exposure to ultraviolet (UV) light).The deposition of the masking composition layer can be carried out selectively on the surface of the flat substrate, by any known and suitable application technique, and for example by screen printing, pad printing, flexography, gravure printing and / or direct printing (for example, drop-by-drop or "inkjet"), which makes it possible to achieve a resolution of the electroconductive pattern(s) 5 of less than 20 μm. Alternatively, the formation of the temporary masking coating by photolithography for example, from said masking composition can make it possible to obtain resolutions of the electroconductive pattern(s) 5 of less than 1 μm, and typically of the order of 100 nm.

[0068] Optional thermoforming step D

[0069] To obtain a component 1 whose substrate 3 has a three-dimensional shape, it is preferable, as mentioned above, that the material of the substrate 3 be chosen to be thermoformable, the substrate 3 then initially having a flat shape (flat substrate). In this case, the method then advantageously comprises a step D of thermoforming the masked substrate obtained at the end of step D of forming a temporary masking coating.

[0070] Step D of thermoforming the masked substrate can advantageously be carried out by any known thermoforming means and technique, obviously adapted to the characteristics of the substrate (nature of the thermoformable material, thickness of the substrate, etc.) and, where appropriate, to the intrinsic characteristics of the temporary masking coating. Typically, step D is carried out by heating the flat substrate in an advantageously homogeneous manner, by conduction and / or by convection and / or by radiation, until the thermoformable material of the substrate is brought to a forming temperature sufficient to make the flat substrate malleable. The forming temperature in question can obviously vary depending on the thermoformable material chosen.For a thermoformable polymer material, the forming temperature is typically chosen to be at least equal to a glass transition temperature of the material in question, and therefore advantageously lower than the melting temperature of the material in question. Once made malleable, the flat substrate is pressed against a male (positive mold) or female (negative mold) mold (or counterform), advantageously with vacuum suction and / or pressure, so that the flat substrate deforms and takes the shape of the mold. The deformed substrate is then cooled so that the thermoformable material hardens and retains the shape imparted by the mold, then the deformed substrate is extracted from the mold.

[0071] Since the substrate and the temporary masking coating are simultaneously thermoformed (or thermodeformed) during thermoforming step D, it is appropriate for the temporary masking coating itself to be advantageously thermoformable, or at least thermodeformable, so as to be able to undergo elongation and thus follow the deformation of the substrate, while adhering to the surface of the latter, during thermoforming step D. The temporary masking coating is thus advantageously designed, in particular in terms of its capacity for elongation / deformation without breaking, to be able to undergo the conditions for carrying out step D of thermoforming the substrate, without significant degradation of its function of masking the surface of the latter.In order to ensure perfect control of the shape of said electroconductive pattern 5 that one seeks to obtain on the surface of the thermoformed substrate, it is advantageous to provide, before the aforementioned step C, a step E of defining a two-dimensional masking pattern, according to which the temporary masking coating is then formed on the surface of the substrate during said step C of forming the temporary masking coating, from a modeling of a deformation of the substrate and of the temporary masking coating, during the thermoforming step D and a representation (or modeling) of said at least one electroconductive pattern 5 to be obtained.In other words, a two-dimensional masking pattern is defined by “inverse anamorphosis”, so that this two-dimensional masking pattern, according to which the temporary masking coating is formed on the surface of the substrate during step C, makes it possible to obtain the desired electroconductive pattern(s) 5 by anticipating and compensating for the effects of the deformation caused by the thermoforming step D. The step of defining such a two-dimensional masking pattern can be carried out using commercially available computer software, such as, for example, the T-SI P software from SIMCON (formerly CADFLOW), the PAM-FORM™ software from ESI GROUP, the ANAMAP™ software solution from KALLISTO or the Thermo 3D™ software from QUADRAXIS.

[0072] Step F of increasing the energy of the dielectric surface

[0073] The method preferably comprises a step F of increasing the surface energy of the dielectric surface 4 of the substrate 3 to bring said surface energy to a value greater than or equal to 50 or 55 dynes, preferably greater than or equal to 60 or 65 dynes, and even more preferably greater than or equal to 70 dynes. This makes it possible to ensure sufficient wetting of the substrate for its metallization, and thus sufficient adhesion of the metal deposit obtained after metallization and intended to form the electroconductive pattern(s) 5. Step F can occur before or after step C of forming the temporary masking coating.

[0074] Step F of treatment to increase the surface energy of the substrate can be carried out: by physical treatment, preferably chosen from the following physical treatments: flaming, plasma treatment, corona treatment, and combinations thereof, and / or

[0075] - by chemical treatment, preferably chosen from the following chemical treatments: application of a silane-based solution, depassivation of the surface using one or more acid solutions, polishing using rare earth oxide, fluorination, acid or alkaline chemical attack to create micro-roughness and combinations thereof.

[0076] More preferably, the physical treatment is a treatment by flaming and / or by plasma, in the case in particular where the substrate, flexible or rigid, is made of a thermoformable polymer material or a thermoformable composite material with a polymer matrix. The flaming consists, for example, of passing the substrate under a flame whose temperature is for example between 1,200°C and 1,700°C. The duration of the flaming is generally 4 to 50 seconds. The treatment (by) plasma corresponds, for example, to passing the substrate to be metallized in a plasma torch. For example, the substrate can be subjected to a so-called “a / r” plasma: 80% nitrogen / 20% oxygen at 0.5 mbar (e.g. 50 Pa) for 2 min. More preferably, the chemical treatment is a fluorination treatment, in the case where the substrate, flexible or rigid, is made of a thermoformable polymer material or a thermoformable composite material with a polymer matrix.Fluorination corresponds, for example, to bringing into contact, in an enclosure under reduced pressure, the substrate to be metallized and a gaseous solution based on inert gas (argon) containing a fluorine additive.

[0077] Step G of wetting the dielectric surface

[0078] The method may comprise, after step F of treatment to increase the surface energy, a step G of wetting the dielectric surface 4, which typically consists of coating the dielectric surface 4 with a liquid film, for example by spraying or by vaporization / condensation of a wetting liquid, to promote the subsequent spreading of the metallization solution(s) (“oxidation-reduction solution(s)”). The choice of the wetting liquid is preferably made from the following group: deionized or non-deionized water, optionally with one or more anionic, cationic or neutral surfactants added, an alcoholic solution comprising one or more alcohols (for example isopropanol, ethanol and their mixture), and their mixtures. For example, deionized water with an anionic surfactant and ethanol added may be chosen as the wetting liquid.The wetting time depends on the dielectric surface 4 considered and the spraying or vaporization / condensation rate of the wetting liquid.

[0079] Step H of activation / sensitization of the dielectric surface

[0080] In the context of metallization by non-electrolytic deposition by projection of one or more metallization solutions in the form of aerosols, a prior activation (or at least “sensitization”) step H may be necessary for the deposition of certain metals. It aims in particular to accelerate the metallization oxidation-reduction reaction. During step H, the surface of the substrate is brought into contact with at least one sensitizing chemical species, which is absorbed onto the surface of the substrate 3 and which will then accelerate the metallization reaction.

[0081] Preferably, the activation step H is carried out after the step C of forming the temporary masking coating, so that the sensitizing chemical species(s) are therefore absorbed both on the temporary masking coating and on the unmasked area(s), i.e. not covered, by the latter.

[0082] In practice, step H is preferably carried out by spraying at least one sensitizing solution onto the surface of the substrate, by any known and appropriate means, such as, for example, using a compressed air paint gun (for example, a High Volume Low Pressure (HVLP) spray gun). Alternatively, step H could be carried out by immersing the substrate in at least one sensitizing solution.

[0083] For example, a first sensitizing solution based on stannous chloride (SnCl2) or SnSCU / ^SCU / quinol / alcohol is applied by spraying or immersion. A palladium or silver solution capable of reacting with Sn ions is then deposited in the same way. 2+to form nucleation centers on the surface of the substrate, or even a colloidal PdSn solution formed ex situ. For more details, one can refer for example to "Metal Finishing Guidebook and Directory Issue", 1996 Metal Finishing publication, pages 354, 356 and 357. H. Narcus, to ". Metallizing of Plastics", Reinhold Publishing Corporation, 1960, Chapter 2, page 21. F. Lowenheim, or even to "Modern electroplating", John Wiley & Sons publication, 1974 Chapter 28, page 636. Advantageously, the sensitization of the surface of the substrate is implemented by means of a sensitization solution based on stannous chloride, for example in accordance with the method of implementation described in document FR- 2 763 962 B1. In this case, a rinsing step using a rinsing liquid is carried out immediately after sensitization, without an intermediate step.According to a variant, the activation of the surface of the substrate 3 is carried out by means of a sensitization solution, in particular palladium chloride, for example in accordance with the implementation method described in document FR-2 763 962 B1. In this case, a rinsing step using a rinsing liquid as described in the examples below is carried out immediately after the activation step H, without an intermediate step.

[0084] Stage I of metallization by non-electrolytic chemical deposition

[0085] The method then comprises a metallization step I, for the formation of a metal deposit intended to form the electroconductive pattern(s) 5 in metal, which is carried out by non-electrolytic chemical deposition from:

[0086] - either a single metallization solution containing said at least one metal in the form of a metal cation and said at least one reducing agent capable of transforming the metal cation into metal,

[0087] - either two separate solutions: the first solution (“oxidizing solution”) containing at least one metal in the form of a metal cation (oxidant(s)) and the second solution (“reducing solution”) containing one or more reducer(s),

[0088] - or a plurality of separate solutions, each of which may contain either at least one metal in the form of a metal cation (oxidant(s)), or one or more reducing agents, provided that at least one of the solutions ("oxidizing solution") contains at least one metal in the form of a metal cation and that at least one other of the solutions ("reducing solution") contains one or more reducing agents. The reducing agent is advantageously chosen to be strong enough to reduce the metal cation to metal, i.e. the standard redox potential of the oxidizing / reducing agent pair of the chosen reducing agent is lower than that of the oxidizing / reducing agent pair of the oxidant (gamma rule).Such a non-electrolytic variant is particularly advantageous in that it allows the formation, on the surface of a substrate which is indifferently conductive or not, of a solid metal deposit, as envisaged above, which is moreover of a thickness advantageously included in the above-mentioned ranges of values.

[0089] During metallization step I, the metallization solution(s) is / are sprayed in the form of one or more aerosol(s) onto the masked substrate, and in particular at least onto the unmasked area(s) thereof. By "aerosol" is meant here a set of fine particles of the metallization solution(s) suspended in a gaseous medium (for example, air). It may thus advantageously be a mist of droplets of size less than 100 pm, preferably less than 60 pm, and even more preferably from 0.1 pm to 50 pm, obtained by nebulization and / or by atomization of the metallization solution(s).

[0090] Advantageously, the metallization solution(s) ("oxidation-reduction solutions") may be obtained from solutions, advantageously aqueous, of one or more oxidizing metal cations (typically obtained by dissolving one or more corresponding metal salts) and one or more reducing compounds, preferably by dilution of concentrated stock solutions, the diluent preferably being demineralized water. Depending on the nature of the metal deposit to be formed, the projection of the metal solution(s) may be carried out continuously, i.e. in a single operation, or discontinuously by alternating projection phases and relaxation times. For example, for a silver-based metal deposit, the projection will preferably be carried out continuously.For example, for a nickel-based metal deposit, the projection will preferably be carried out discontinuously by alternating projection phases and relaxation times. Depending on the desired thickness of the metal deposit, the projection time can advantageously vary between 0.5 s and 200 s, preferably from 1 s to 50 s and even more preferably from 2 s to 30 s for a substrate surface to be metallized of 1 dm. 2 The projection of the metallization solution(s) can be carried out using any suitable spraying means, preferably using one or more compressed air paint guns, such as for example one or more high volume low pressure (HVLP) guns.

[0091] According to a first projection method, one or more solutions of metal cation(s) ("oxidizing solution(s)") and one or more solutions of reducing agent(s) ("reducing solution(s)") are simultaneously and continuously projected onto the surface to be treated, in the form of one or more aerosols. In this case, the mixing between the oxidizing solution and the reducing solution can be carried out just before the formation of the aerosol or by fusion of an aerosol produced from the oxidizing solution and an aerosol produced from the reducing solution, preferably before coming into contact with the surface of the substrate. According to a second projection method, one or more solutions of metal cation(s) ("oxidizing solution(s)") are successively projected, by means of one or more aerosols, then one or more solutions of reducing agent(s) ("reducing solution(s)").In other words, the projection of the redox solution is carried out by separate projection(s), alternately, of one or more solutions of one or more metal oxidants and one or more solutions of one or more reducers. According to a third projection method, a metallization solution, made metastable, containing a mixture of said at least one metal in the form of a metal cation ("oxidant(s)") and said at least one reducer is sprayed in the form of an aerosol, then, after projection onto the surface of the substrate, the metallization solution is activated so that the transformation of the metal cation(s) into metal is triggered, preferably by contact with an initiator, advantageously provided via one or more aerosols, before, during or after the projection of the metallization solution.The initiation or activation of the redox reaction can then be obtained by any appropriate physical (temperature, UV, etc.) or chemical means.

[0092] Preferably, water is chosen as the solvent for the preparation of the metallization solution(s) to be sprayed in the form of aerosol(s). The concentration(s) of metal salt(s) in the oxidizing solution(s) to be sprayed are preferably between 0.1 g / l and 100 g / l and more preferably between 1 g / l and 60 g / l. Where appropriate, the concentration(s) of metal salt(s) in the stock solution(s) are preferably between 0.5 g / l and 500 g / l, or the dilution factor of the stock solution(s) is preferably between 5 and 5,000. Advantageously, depending on the nature of the metal of the electroconductive pattern 5 to be obtained, the metal salts are chosen from silver nitrate, nickel sulfate, copper sulfate, tin chloride, aurochloric acid, iron chloride, cobalt chloride and mixtures thereof.The selection of the reducing agent(s) is preferably made from the following compounds: borohydrides, dimethylaminoborane, hydrazine, sodium hypophosphite, formalin, lithium aluminum hydride, reducing sugars such as glucose derivatives or sodium erythorbate, and mixtures thereof. The concentration(s) of metal salt(s) in the reducing solution(s) to be sprayed are preferably between 0.1 g / l and 100 g / l, and more preferably between 1 g / l and 60 g / l. Where appropriate, the concentration(s) of reducing agent(s) in the stock solution(s) are preferably between 0.5 g / l and 250 g / l, or the dilution factor of the stock solution(s) is preferably between 5 and 2,500.

[0093] For example, an electroconductive pattern 5 in pure silver Ag can be obtained by simultaneous projection in the form of an aerosol (first projection method) of a first aqueous metallization solution (oxidizing solution) based on silver nitrate at a concentration of 2 g / l and having a pH > 9, and of a second metallization solution (reducing solution) based on glucose, for 80 s using HVLP guns set at a spray pressure of less than 2.5 bar ( / .e. 2.5.10 5 Pa).

[0094] Step J of removing the temporary masking coating

[0095] The method further comprises a step J of removing the temporary masking coating, which aims to remove the temporary masking coating present on the substrate 3, as well as any metal deposit which may have formed on the temporary masking coating at the end of the metallization step I, and thus to “reveal” the electroconductive pattern(s) 5 made of metal.

[0096] Advantageously, step J is carried out at least partially by chemical, non-mechanical means, in order to remove said temporary masking coating in a simple and clean manner, while limiting the risk of degrading the fineness and precision of the electroconductive pattern(s) 5 that it is sought to obtain. Advantageously, step J of removing the temporary masking coating is carried out during metallization step I, or at least partly during step I and after step I, or at least partly during and after step I and partly before step I. As such, step J of removing the temporary masking coating comprises at least (or even essentially consists of) an operation of dissolving (at least partially) the temporary masking coating by at least one solvent contained in the or one of the metallization solutions used during metallization step I.Here, the term "dissolution by at least one solvent" means a disintegration, a disintegration, a loss of cohesion, total or partial, of the temporary masking coating, under the action of a particular fluid (a liquid, preferably) chosen for its specific chemically aggressive character with respect to the temporary masking coating, such as to allow its disintegration, its separation and its evacuation from the surface of the substrate. It may thus be a dissolution mechanism in a solvent in the strict chemical sense, but not necessarily.

[0097] Preferably, said temporary masking coating is alkali-soluble (or at least alkali-sensitive) so as to be able to be preferentially dissolved by an alkaline solvent contained in the or one of the metallization solutions used during step I. In practice, the (or one of the) chosen metallization solution(s) has(have) a strongly alkaline pH (typically greater than 9), so that the metallization solution(s) can dissolve the temporary masking coating during the metallization step I. Thus, during the projection of the metallization solution(s) in the form of aerosol(s), the unmasked areas of the substrate are metallized, while the temporary masking coating is dissolved and evacuated in the effluents, thus revealing the desired electroconductive metal pattern(s).

[0098] Step J may optionally comprise, prior to said operation of dissolving the temporary masking coating, an operation of exposure under actinic radiation (for example, under UV light) and / or an operation of heat treatment of the temporary masking coating, in order to weaken the temporary masking coating and / or to facilitate its subsequent dissolution. Step J may optionally comprise, after such a dissolution operation, a liquid phase entrainment operation and / or a mechanical entrainment operation by a gas (preferably air), in particular in order to facilitate the evacuation of the dissolved temporary masking coating and / or any debris not completely dissolved therefrom.

[0099] Steps K and L of rinsing and drying the surface of the metallized substrate

[0100] After the metallization step I, the method preferably comprises a step K of rinsing the surface of the metallized substrate, to remove any residues of the temporary masking coating. The rinsing step K can be carried out for example by spraying / projecting one or more rinsing liquids using an HVLP gun or by dipping / immersing in one or more rinsing liquids. The latter is preferably water, and more preferably demineralized water, except possibly in the case where the (or one of the) rinsing liquids contains or forms a solvent (other than water) for dissolving the temporary masking coating, to continue if necessary the step J of removing the temporary masking coating.In particular, after an initial rinse by spraying water, an additional rinse can be carried out by immersion in a bath or by spraying solutions containing a solvent such as ethanol / isopropanol to ensure a complete absence of residues of temporary masking coating and metallic deposits carried by the latter.

[0101] Step K of rinsing the surface of the metallized substrate may be followed by a step L of drying the surface of the metallized substrate to remove the rinsing liquid. Such drying may typically be carried out at room temperature by blowing a stream of compressed air, for example under a pressure of 5 bar ( / .e. 5.10 5 Pa), or using an air knife type blowing system.

[0102] Optional M step of finishing treatment of the surface of the metallized substrate

[0103] Advantageously, a finishing treatment step M of the surface of the metallized substrate may be provided, consisting of the formation of a dielectric upper coating (protective coating), as previously envisaged, which covers at least the upper surface 5B of said at least one electroconductive pattern 5 carried by the substrate 3. Such a finishing step may typically be carried out by deposition / application, by any known and suitable technique, of at least one finishing layer of a curable and / or crosslinkable liquid composition (for example, by UV exposure or by thermal baking) on ​​the surface of the substrate carrying the electroconductive pattern(s) 5. The liquid composition may be a paint or a varnish, advantageously chosen for example from the following group: alkyds, polyurethanes, epoxies, vinyls, acrylics and their mixtures.Preferably, the liquid composition is a varnish, optionally colored / pigmented, advantageously chosen from the following compounds: epoxies, alkyds and acrylics.

[0104] Optional step N for assembling additional elements

[0105] Optionally, the method may comprise a step N of assembling to the substrate 3 thus provided with one or more electroconductive pattern(s) 5 made of metal one or more additional elements, such as an electrical or electronic component, and for example an electronic chip 8 or an electrical connection element 7. Advantageously, such an assembly step N may be implemented using one or more robotic system(s) for placing surface-mounted components (SMD), commonly called “pick-and-place” or “P&P” machines, one or more robotic arms. Such an assembly step may advantageously be carried out by soldering and / or using an electroconductive adhesive, isotropic or anisotropic, taking for example the form of a film or a paste, and of any suitable chemical nature (silicone, epoxy, acrylic, etc.). If necessary, an operation of curing the electroconductive adhesive may be implemented.

[0106] POSSIBILITY OF INDUSTRIAL APPLICATION

[0107] The invention finds its application in the field of design and manufacture of components for electrical, radioelectric or electronic devices, such as in particular for radioelectric devices transmitting and / or receiving radiofrequency waves or for sensors / detectors, comprising a substrate provided with a dielectric surface carrying at least one electrically conductive pattern.

Claims

CLAIMS Component (1) for electrical, radioelectric or electronic device (2), comprising a substrate (3) having a dielectric surface (4) bearing at least one electroconductive motif (5), said electroconductive motif (5) having a lower surface (5A) in contact with said dielectric surface (4) and an opposing upper surface (5B), said component (1) being characterized in that said electroconductive motif (5) is made of metal, the upper surface (5B) of the electroconductive motif (5) having a roughness Sa which is less than or equal to 500 nm, said electroconductive motif (5) having a thickness (e) between 10 nm and 500 nm and a foil resistance which is less than or equal to 800 mQ / n.Component (1) according to the preceding claim, characterized in that the roughness Sa of the upper surface (5B) of the electroconductive pattern (5) is less than or equal to 300 nm, preferably less than or equal to 200 nm, preferably less than or equal to 100 nm, preferably less than or equal to 50 nm, preferably less than or equal to 20 nm, and preferably even less than or equal to 15 nm. Component (1) according to any one of the preceding claims, characterized in that the lower surface (5A) of the electroconductive pattern (5) has a roughness Sa that is less than or equal to 500 nm.Component (1) according to the preceding claim, characterized in that the roughness Sa of the lower surface (5A) of the electroconductive pattern (5) is less than or equal to 300 nm, preferably less than or equal to 200 nm, preferably less than or equal to 100 nm, preferably less than or equal to 50 nm, preferably less than or equal to 20 nm, and preferably even less than or equal to 15 nm. Component (1) according to any one of the preceding claims, characterized in that the thickness (e) of the electroconductive pattern (5) is less. or equal to 400 nm, preferably less than or equal to 300 nm, and preferably less than or equal to 200 nm. Component (1) according to any one of the preceding claims, characterized in that said metal is selected from the group comprising: silver Ag, nickel Ni, gold Au, copper Cu, aluminum Al, iron Fe, and tin Sn and their alloys. Component (1) according to the preceding claim, characterized in that said electroconductive motif (5) is formed of an elemental metal, namely silver Ag. Component (1) according to any one of the preceding claims, characterized in that the metal of the electroconductive motif (5) is more than 90% pure, preferably more than 95% pure, and preferably more than 98% pure.Component (1) according to any one of the preceding claims, characterized in that the electroconductive motif (5) has a foil resistance that is less than or equal to 100 mQ / n, and preferably less than or equal to 40 mQ / n. Component (1) according to any one of the preceding claims, characterized in that said electroconductive motif (5) has a resolution that is less than or equal to 100 pm, preferably less than or equal to 20 pm, and preferably less than or equal to 1 pm. Component (1) according to any one of the preceding claims, characterized in that it comprises at least one electrical connection element (7) fixed to the substrate (3) and in electrical contact with said electroconductive motif (5).Component (1) according to any one of the preceding claims, characterized in that the substrate (3) is made of polymer material, polymer matrix composite material, paper, glass, textile, leather or ceramic material. A component (1) according to any one of the preceding claims, characterized in that a surface of the substrate (3) is covered with an intermediate coating (6) forming said dielectric surface (4) provided with said electroconductive pattern (5). A component (1) according to any one of the preceding claims, characterized in that said substrate (3) and said electroconductive pattern (5) have a three-dimensional shape, said substrate (3) preferably being a thermoformed substrate. An electrical, radioelectric, or electronic device (2) comprising a component (1) according to any one of the preceding claims. A device (2) according to the preceding claim, characterized in that it constitutes a radioelectric device, said electroconductive pattern (5) forming a radiating element of a radio frequency antenna.Device (2) according to claim 15, characterized in that it constitutes a sensor, said electro-conductive motif (5) forming a sensor electrode, for example a capacitive or resistive sensor electrode.

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