Method for manufacturing an electronic device, and resulting electronic device

Abstract

The invention relates to a method for manufacturing an electronic device, which method comprises the following successive steps: - depositing (52) at least one first pattern on a substrate, the at least one first pattern being made of a first material, the first material being an ink comprising micro-particles and / or nano-particles bound by a polymeric binder; - depositing (55) a layer made of a second material on the first pattern and on the substrate, the second material comprising a monomer and a hardener or an uncured polymer, the polymeric binder being shaped to react with the second material; - soaking (56) the first material with the second material; - curing (58) the second material so as to form a solid micro-composite and / or nano-composite and a support incorporating the micro-composite and / or nano-composite; - separating (60) the electronic device from the substrate.

Description

[0001] DESCRIPTION

[0002] TITLE: Process for manufacturing an electronic device and electronic device

[0003] Technical field of the invention

[0004] The invention relates to a method for manufacturing an electronic device and an electronic device obtained by this method.

[0005] Prior art

[0006] Electronic devices are manufactured by depositing different types of ink onto a substrate. Typically, inks are synthesized from polymers, colloids, and ceramics suspended or dispersed in a solvent. The ink must be sufficiently fluid to be printable. It must also be homogeneous and stable over time to allow for commercial sale in jars. After printing, the inks dry. During this drying process, the inks harden. Once hardened, the substrate and inks form an electronic device with properties such as resistance and electrical conductivity, which are related to the composition of the inks.

[0007] Presentation of the invention

[0008] One aim of the present invention is to propose a method for manufacturing electronic devices having improved sensitivity.

[0009] In particular, one aim of the present invention is to propose a method for manufacturing a strain gauge having improved sensitivity.

[0010] In particular, another objective of the present invention is to propose a method for manufacturing a humidity sensor having improved sensitivity.

[0011] In particular, another objective of the present invention is to propose a method for manufacturing a temperature sensor having improved sensitivity.

[0012] Summary of the invention

[0013] The present invention relates to a method for manufacturing an electronic device comprising the following successive steps:

[0014] - the deposition of at least one first motif on a substrate, the at least one first motif being made in a first material, the first material being an ink comprising micro and / or nano particles linked by a polymeric binder, - the deposition of a layer of a second material on the first motif and on the substrate, the second material comprising a monomer and a hardener or an unpolymerized polymer, said polymeric binder being shaped to react with the second material,

[0015] - the imbibition of the first material by the second material,

[0016] - the polymerization of the second material to form a solid micro and / or nano composite and a support incorporating said micro and / or nano composite,

[0017] - the detachment of the electronic device from the substrate.

[0018] Advantageously, the second material reacts with the first material to form a micro and / or nano composite with improved sensitivity.

[0019] Advantageously, the support for the micro and / or nano composite is created at the same time as the micro and / or nano composite.

[0020] The features described in the following paragraphs may optionally be implemented. They may be implemented independently or in combination with each other:

[0021] - The second material includes one material from among an epoxy resin, an acrylic resin, a silicone.

[0022] Advantageously, the use of an epoxy resin allows the manufacture of pressure sensor patterns with greater sensitivity to mechanical stresses.

[0023] - The second material comprises pyrrolidone or polyphenol alcohol. Advantageously, the use of this second material makes it possible to manufacture a humidity sensor that is more sensitive to humidity.

[0024] - The first material comprises a material from among carbon and silver.

[0025] - The first material is porous.

[0026] - The substrate has a surface energy of less than 0.6 newton / meter.

[0027] - The substrate has a non-stick coating, between 5 and 1000 g / 5 cm.

[0028] - The substrate includes a material such as silicon, Teflon layers, fluorinated layers, a release film, a vinyl transfer film.

[0029] - The substrate is a substrate comprising polyethylene and / or polyamide.

[0030] - The process includes the deposition of at least one second motif on at least part of the substrate, the second motif is made of a conductive material such as, for example, silver, copper and gold.

[0031] - The process includes depositing a barrier layer on at least part of the first pattern.

[0032] - The process involves increasing substrate adhesion.

[0033] The invention relates to an electronic device obtained by the manufacturing process mentioned above, the electronic device being a sensor among a gauge sensor, a humidity sensor and a temperature sensor.

[0034] Brief description of the figures

[0035] [Fig. 1] is a diagram representing the steps of the manufacturing process according to the invention;

[0036] [Fig. 2] is a schematic view of a substrate used to implement the process according to the invention;

[0037] [Fig. 3] is a schematic view of the substrate illustrated in figure 2 after treatment of its upper face;

[0038] [Fig. 4] is a schematic view of the substrate on which patterns have been deposited; [Fig. 5] is a schematic view of the substrate illustrated in Figure 4 comprising a layer of a second material;

[0039] [Fig. 6] is a schematic view of an example of an electronic device obtained by the manufacturing process according to the invention;

[0040] [Fig. 7] is a graph representing the relative variation of resistance as a function of the deformation applied to two gauge sensors;

[0041] [Fig. 8] is a graph representing the relative variation of resistance as a function of humidity level and time for two humidity sensors;

[0042] [Fig. 9] is a graph representing the relative variation of resistance as a function of temperature for two temperature sensors;

[0043] [Fig. 10] is a front view of an electronic device manufactured according to the invention.

[0044] Detailed description of the invention

[0045] The invention relates to a method for manufacturing a micro and / or nano composite. With reference to Figures 1 and 2, an example of the manufacturing method according to the invention begins with a step 50 of supplying a substrate 100.

[0046] Substrate 100 comprises or is made up of a silicon layer.

[0047] In one variant, substrate 100 comprises or is made up of Teflon layers. In a second variant, substrate 100 comprises or is made up of fluorinated layers. In a third variant, the substrate comprises or is made up of polyethylene and polyamide. The substrate is then produced by coextrusion. For example, the film marketed by the company "Sicomin" (registered trademark) under the brand name "Nylex S2 70 pm" (registered trademark) can be used as the substrate. In a fourth variant, substrate 100 is a release film. For example, a release film marketed by the company "Pacothane" (registered trademark) and referenced as 1500 can be used. This film can, for example, have a thickness of 45 microns.

[0048] According to a fifth variant, the substrate is a vinyl transfer film. For example, a vinyl transfer film marketed by the company "Propeel" (registered trademark) can be used. This film can, for example, have a thickness of 100 microns.

[0049] The substrate includes an upper face 101 of the substrate 100 having an adhesion allowing temporary attachment of a first material, a second material and possibly a third material, and detachment of these, as explained later.

[0050] Preferably, the upper face 101 of the substrate has an anti-stick coating, between 5 and 1000 g / 5 cm.

[0051] Put another way, the upper face 101 of the substrate may have a surface energy of less than 0.6 newton / meter.

[0052] With reference to Figure 3, the process may optionally include a step 51 of treating the upper surface 101 of the substrate to achieve the desired adhesion. In Figure 3, the thick line schematically represents the upper surface 101 after treatment.

[0053] In particular, the processing step may be a step to reduce substrate adhesion. If the substrate 100 is silicon, the adhesion reduction step may, for example, include polishing the top face 101 of the substrate.

[0054] Decreased adhesion can also be achieved, or in addition, by the deposition of fluoropolymers via liquid or gaseous methods. Increased adhesion can further involve the formation of hydroxyl groups, for example, by treatment with O2 plasma or UVO3 plasma.

[0055] The process includes a step 52 in which a first pattern 202 is deposited on the upper surface 101 of the substrate 100. The first pattern 202 is, for example, printed. The printing can be carried out by screen printing or by inkjet printing.

[0056] The first pattern 202 is made of a first material. The first material comprises micro and / or nanoparticles. Preferably, the first material is an ink. The first material may contain carbon. For example, the first material is a carbon ink marketed by the company "VFP Ink Technologie" (registered trademark).

[0057] The micro- and / or nanoparticles of the first material are bound by a polymeric binder and a solvent. Alternatively, the first material is a porous aggregate deposited on the upper surface 101 of the substrate. The ink is a conductive and resistive ink. The ink comprises conductive nanoparticles, a solvent, and a binding polymer. The presence of the binding polymer is essential to ensure the colloidal stability of the ink by preventing nanoparticle aggregation during storage (pot life), limiting the porosity of the deposit once dried, and creating a usable chemical interface with the "second material."

[0058] With reference to Figure 4, the process may optionally include a step 53 of depositing a second motif 201 onto the upper surface 101 of the substrate. The second motif 201 is made of a conductive material. This conductive material is, for example, silver, copper, or gold. The second motif 201 has, for example, the shape of a conductive track or the shape of an electrical connection pad.

[0059] Alternatively, step 53 can be implemented before step 52. In this case, the first pattern 202 can be printed partly on the second pattern 201 and on the first pattern 202.

[0060] The process may also include a step 54 in which a barrier layer 203 is deposited on at least a portion of the first motif 202. The barrier layer 203 is, for example, a varnish. The barrier layer is deposited only when it is desired to manufacture an electronic device having an area that is less sensitive or insensitive to stress, humidity, or temperature.

[0061] With reference to Figure 5, the process includes a step 55 of depositing a layer 300 of a second material onto the first motif 202 and onto the upper face 101 of the substrate. The second material comprises, on the one hand, a hardener and, on the other hand, a monomer or an unpolymerized polymer.

[0062] The second material is in liquid or viscous form. The process includes a step 56 in which the first material is soaked by the second material. When the first material is porous, the second material dissolves and mixes with the first material. When the first material contains a polymeric binder, the second material mixes with the polymeric binder. The polymeric binder is, for example, a polyester. When a barrier layer 203 has been deposited on a portion of the first pattern 202, the second material does not soak or react with the first material deposited beneath the barrier layer 203.

[0063] The process includes a step 58 of polymerization of the second material. During polymerization, the second material, which has soaked the micro and / or nanoparticles, swells and separates the micro and / or nanoparticles from each other. Advantageously, the second material reacts with the first material to form a micro and / or nanocomposite 204 with improved sensitivity.

[0064] After polymerization, the micro and / or nanoparticles of the first material and the second material formed a solid micro and / or nano composite 204. After polymerization, layer 300 formed a support 301 incorporating said micro and / or nano composite 204. When the micro and / or nanoparticles of the first material are bonded by a polymeric binder, the second material mixes with the polymeric binder of the first material, and then the materials polymerize.

[0065] Advantageously, the 301 support is created at the same time as the micro and / or nano composite 204.

[0066] Referring to Figure 6, the process includes a step 60 of detaching an electronic device 205 from the substrate 100. The substrate 100 was used temporarily and only during the fabrication of the electronic device. The substrate is removed after fabrication of the electronic device. It is replaced by the support 301.

[0067] The electronic device 205 formed by the example process described above includes the support 301, the micro and / or nano composite 204, the second motif 201 forming an electrical connection element, the barrier layer 203 and a part of the first motif located under the barrier layer.

[0068] The second material may include one of the following: epoxy resin, acrylic resin, silicone.

[0069] Alternatively, the second material may include pyrrolidone or polyphenol alcohol. The second material may also include fiberglass or flax fiber to increase its rigidity.

[0070] The electronic devices 205 advantageously exhibit greater sensitivity to mechanical stresses. This electronic device 205 can be used as a gauge sensor 206. Indeed, Figure 7 is a graph representing the relationship between the change in resistance AR and an initial resistance RO as a function of an applied deformation ε for a gauge sensor 206 obtained by the manufacturing process according to the invention (curve 62) and for a conventional gauge sensor (curve 64). As can be seen from this graph, the change in resistance is greater for the gauge sensor obtained by the present invention. This gauge sensor is therefore more sensitive and exhibits a better stress detection capability than a conventional gauge sensor.

[0071] The formed electronic devices 205 can also be used as humidity sensors 207. These humidity sensors are more sensitive to humidity than conventional humidity sensors.

[0072] Figure 8 shows the relationship between the relative variation of resistance as a function of the humidity level of the medium and time for a humidity sensor 207 obtained by the manufacturing process according to the invention (curve 66) and for a conventional humidity sensor (curve 68). For example, the term "40% RH" means that the medium has a relative humidity of 40%. As can be seen in this graph, the humidity level detection is more important for the humidity sensor 207 obtained by the process according to the present invention than for a humidity sensor obtained conventionally from a humidity level of 50%.

[0073] The 207 humidity sensor therefore detects the presence of humidity more sensitively and more quickly than a conventional humidity sensor.

[0074] The formed electronic devices 205 can also be used as a temperature sensor 208. Figure 9 shows the ratio between the change in resistance AR and an initial resistance R0, expressed as a percentage, as a function of the ambient temperature for a temperature sensor 208 obtained by the manufacturing process according to the invention (curve 70) and for a conventional temperature sensor (curve 72). As can be seen from this graph, the temperature detection is more accurate for the temperature sensor 208 obtained by the process according to the present invention than for a conventionally obtained temperature sensor, starting from a temperature of 30 degrees Celsius and, in particular, from a temperature of 50 degrees Celsius.

[0075] Figure 10 shows an example of an electronic device 205 manufactured using the method according to the invention. The electronic device 205 comprises a support 301 incorporating glass fiber, four micro and / or nano composites 204, and eight electrical tracks 206 formed by second motifs 201. In the illustrated example, the second motifs were formed on the support 301 and partly on the micro and / or nano composites 204.

[0076] Steps 50, 52, 55, 56, 58, and 60 of the process described above are carried out in the order described above. Steps 53 and 54 may be carried out in a different order.

[0077] Alternatively, the process does not include step 51 of treatment of the upper face 101 of the substrate.

[0078] Alternatively, the process omits step 54 of depositing a barrier layer 203. In this case, the entire first motif 202 is polymerized. The resulting electronic device 205 then comprises the support 301, the micro and / or nano composite 204, and the second motif 201, which forms an electrical connection element. Finally, alternatively, the process omits step 53 of depositing a second motif 201 onto the substrate. In this case, the resulting electronic device comprises the support 301, the micro and / or nano composite 204, the barrier layer 203, and a portion of the first motif located beneath the barrier layer.

[0079] When the process does not include steps 51 and 53, the electronic device formed comprises the support 301 and the micro and / or nano composite 204.

[0080] The dispersion state of micro- and / or nanoparticles plays a dominant role in the electrical properties (conductivity, dielectric) of micro- and / or nanocomposites. This is due to the influence of particle aggregation on the formation of electrical networks. Larger aggregates and entanglements lead to a higher percolation threshold, defined as the point at which the insulating material becomes electrically conductive. The highest sensitivities are obtained at concentrations close to the onset of percolation, due to the dominant effect that the tunneling distance between adjacent particles has on the electromechanical behavior of the composites. The manufacturing process allows for the insertion of a second material into the micro- and / or nanoparticle network and the spontaneous formation of a micro / nanocomposite with increased sensitivity in two consecutive depositions.

[0081] Advantageously, the second material does not necessarily possess the rheological properties enabling it to be printable by printing processes since it can be deposited after printing the first material by coating techniques such as centrifugation, vacuum infusion, syringe deposition.

[0082] Advantageously, the first and second materials would not have been printable if they had been mixed before deposition. Indeed, the instability over time of such a mixture is incompatible with a manufacturing process for ink that is stable over time and commercially viable.

[0083] The second material is selected for its chemical affinity with the ink's binding polymer, enabling it to partially dissolve or extract the binding polymer. This interaction triggers an imbibition process in which the initial binder is replaced or reorganized within the polymer matrix of the substrate.

[0084] This imbibition mechanism can only occur if there is chemical compatibility between the binder and the polymer of the "second material". Otherwise, no synergy appears and the deposit retains a conventional behavior, comparable to known solutions.

[0085] The combination of (i) ink comprising a polymer binder and (ii) chemically compatible polymer support makes it possible to obtain, after imbibition, a hybrid / composite material exhibiting improved homogeneity of the conductive network formed by the nanoparticles, a reduction of residual porosity, and enhanced detection properties in mechanical stress, temperature and humidity, etc.

Claims

DEMANDS 1. A method for manufacturing an electronic device (205) comprising the following successive steps: - the deposition (52) of at least one first motif (202) on a substrate (100), the at least one first motif being made in a first material, the first material being an ink comprising micro and / or nano particles linked by a polymeric binder, - the deposition (55) of a layer of a second material on the first motif (202) and on the substrate (100), the second material comprising a monomer and a hardener or an unpolymerized polymer, said polymeric binder being shaped to react with the second material, - the imbibition (56) of the first material by the second material, - the polymerization (58) of the second material so as to form a solid micro and / or nano composite (204) and a support (301) incorporating said micro and / or nano composite, - the decoupling (60) of the electronic device from the substrate (100).

2. A manufacturing method according to claim 1, wherein the second material comprises a material from an epoxy resin, an acrylic resin, a silicone.

3. A manufacturing process according to claim 1, wherein the second material comprises pyrrolidone or polyphenol alcohol.

4. A manufacturing method according to any one of claims 1 to 4, wherein the first material comprises a material from carbon and silver.

5. A manufacturing process according to any one of claims 1 to 5, wherein the first material is porous.

6. A manufacturing method according to any one of claims 1 to 5, wherein the substrate (100) has a surface energy of less than 0.6 Newton / meter.

7. A manufacturing process according to any one of claims 1 to 5, wherein the substrate (100) has an anti-sticking capacity of between 5 and 1000 g / 5 cm.

8. A manufacturing method according to any one of claims 1 to 7, wherein the substrate (100) comprises a material among silicon, Teflon layers, fluorinated layers, a release film, a vinyl transfer film.

9. A manufacturing process according to any one of claims 1 to 8, wherein the substrate (100) is a substrate comprising polyethylene and / or polyamide.

10. A manufacturing method according to any one of claims 1 to 9, comprising the deposition (53) of at least one second motif (201) on at least a part of the substrate, the second motif being made of a conductive material such as, for example, silver, copper and gold.

11. A manufacturing method according to any one of claims 1 to 10, wherein the method comprises the deposition (54) of a barrier layer (203) on at least a part of the first motif (202).

12. A manufacturing process according to any one of claims 1 to 11, wherein the process includes an increase (51) in the adhesion of the substrate (100).

13. Electronic device obtained by the manufacturing process according to any one of claims 1 to 12, wherein the electronic device comprises a sensor among a gauge sensor (206), a humidity sensor (207) and a temperature sensor (208).

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