KR20220103097A - Method for manufacturing silicon substrate or silicon-composite substrate, silicon substrate or silicon-composite substrate produced by the method, and uses thereof - Google Patents

Abstract

The present invention relates to a method for manufacturing a silicon substrate or a silicon composite substrate, wherein at least one silicon selected from the group consisting of alkoxysilanes, hydroxysilanes, and mixtures thereof is provided, wherein at least one liquid oligosiloxane is A first crosslinking reaction prepared by a sol-gel reaction from at least one silane, wherein at least some crosslinking of the at least one oligosiloxane is performed to form a silicone material, and more extensive crosslinking of the silicone material A second crosslinking reaction is carried out in at least one portion of the silicone material, wherein the first crosslinking reaction and the second crosslinking reaction are orthogonal to each other.

Description

Method for manufacturing silicon substrate or silicon-composite substrate, silicon substrate or silicon-composite substrate produced by the method, and uses thereof

The present invention relates to a method for manufacturing a silicon substrate or a silicon composite substrate, wherein at least one silicon selected from the group consisting of alkoxysilanes, hydroxysilanes, and mixtures thereof is provided, wherein at least one liquid oligosiloxane is A first crosslinking reaction prepared by a sol-gel reaction from at least one silane, wherein at least some crosslinking of the at least one oligosiloxane is performed to form a silicone material, and more extensive crosslinking of the silicone material A second crosslinking reaction is carried out in at least one portion of the silicone material, wherein the first crosslinking reaction and the second crosslinking reaction are orthogonal to each other.

Stretchable electronics typically contain rigid functional materials (transistors, LEDs, etc.) that are not stretchable per se on a flexible substrate. There is therefore a technical problem in the manufacture of stretchable (elastomeric) substrates containing locally strengthened “islands” as carrier structures for the electronic components to be applied. The transition between the “soft” and “hard” regions should not be too abrupt in this way to avoid any tearing of the substrate at the point of transition. On the other hand, the difference in the respective mechanical strengths (stretchability, Young's modulus) is such that the elongation of the "hard" region does not exceed a threshold set as low as possible (complete avoidance of elongation is theoretically impossible). ) must be large enough to ensure that only the "soft" area is stretched under the tensile load.

Electronic components are typically initially placed or structured on a rigid substrate and then transferred onto an elastomeric matrix. The embedding of a rigid carrier structure in such an elastomeric matrix for better protection of electronic components against mechanical deformation has been described. For example, Lacour et al. (P. Lacour et al., Appl. Phys. Lett. 2013, 102, 131904) described an initially rigid epoxy resin, which is then embedded in a silicone elastomer, into photolithography. manufactured by To avoid mechanical deformation of the silicone material on the platform, the platform is characterized by a relative thickness, which causes significant strain peaks at the edge of the platform and deformation of the surrounding elastomer.

The preparation of polydimethylsiloxanes with locally varied mechanical strength has been described (S.P. Lacour et al., Appl. Phys. Lett. 2011, 98, 124101); J. Appl. Phys. 2011, 109 , 054905]). The method is based on the use of a single type of crosslinking reaction. The degree of crosslinking of the elastomer is still changed in the flowable state by the use of a mixed photoinhibitor which reduces the number of crosslinkable functional groups under UV exposure. The range of change in Young's modulus is rather moderate by a factor of 2 to 4.5, and an additional support structure, usually made of an inflexible material, for example polyimide, is required. Since activation of the photoinhibitor also occurs prior to thermal vulcanization (contact exposure is not possible due to the tackiness of the prepolymer), the dissolution is relatively small, at least about 60 μm. The preparation according to Lacour et al. is described in detail in International Publication WO 2011/124898.

Finally, photostructurable silicones have also been described in the literature (eg US Patent Application Publication US 2017/0200667). Hydrosilylation with the aid of photoactivatable noble metal catalysts such as Pt(II)-β-diketonate, 115-cyclopentadienyl-Pt(IV)trialkyl, triazine oxide-Pt complexes, and many others. Typical vulcanization by means of is achieved for this purpose. However, photostructuring does not relate to materials with locally different mechanical strength - as in Lacour et al.'s paper - but rather to conventional exposure and development methods for silicon structures (no matrix).

Starting from this, it was an object of the present invention to provide a method for manufacturing a silicon substrate or a silicon composite substrate having regions of different strength.

This object is achieved with respect to a method for manufacturing a silicon substrate or silicon composite substrate according to the features of claim 1 and with respect to a silicon substrate or a silicon composite substrate according to the features of claim 12 . Possibilities for the use of silicon substrates or silicon composite substrates according to the invention are indicated in claim 15 . Each dependent claim represents an advantageous further development.

According to the present invention, there is provided a method for manufacturing a silicon substrate or a silicon composite substrate as follows:

a) at least one silane selected from the group consisting of alkoxysilanes, hydroxysilanes, and mixtures thereof is provided;

b) the at least one liquid oligosiloxane is prepared by a sol-gel reaction from at least one silane;

c) a first crosslinking reaction in which (at least a portion) of the at least one liquid oligosiloxane is crosslinked is performed to form a silicone material;

d) a second crosslinking reaction is carried out in which at least a (locally limited) portion of the silicone material is subjected to a more extensive crosslinking of the silicone material;

wherein the first crosslinking reaction and the second crosslinking reaction are orthogonal to each other.

At least one silane is initially provided in step a) of the process according to the invention. It is selected from the group consisting of alkoxysilanes, hydroxysilanes, and mixtures thereof.

In step b), at least one liquid oligosiloxane is prepared from the at least one silane provided in step a). Here, the fabrication is made by a sol-gel reaction. Liquid oligosiloxanes are preferably understood as oligosiloxanes present in liquid form at room temperature, preferably at 20°C. The at least one liquid oligosiloxane preferably has at least 2 to 100 siloxane units. The at least one oligosiloxane is particularly preferably at least one liquid ORMOCER ^® resin.

In step c) and step d), a multistep crosslinking of at least one oligosiloxane is effected to ultimately obtain the desired silicon substrate or silicon composite substrate. A first crosslinking reaction and a second crosslinking reaction are performed for multi-step crosslinking. In the first crosslinking reaction of step c), at least some crosslinking of the at least one liquid oligosiloxane is made to form a (elastomeric) silicone material (eg elastomeric ORMOCER ^® ). The silicone material may be present, for example, as a film (eg an elastomeric ORMOCER ^® film). In the second crosslinking reaction of step d), a more extensive crosslinking is effected in one or more specific (locally limited) portions of the silicone material. The second crosslinking reaction is here carried out exclusively on at least one specific (topically limited) part of the silicone material, such that a more extensive crosslinking also takes place exclusively on this at least one specific (topically limited) part. As a result, the fabricated silicon substrate or silicon composite substrate has a higher crosslinking density in at least one portion than in the remaining region or remaining regions of the substrate where more extensive crosslinking has not been made. Accordingly, at least one portion also has a higher mechanical strength than the remaining area or remaining areas of the substrate. Due to the higher mechanical strength, at least one portion may also be referred to as a thermoset region, while the remaining region or remaining regions of the substrate may also be referred to as an elastomeric region or elastomeric regions. The fabricated silicon substrates or silicon composite substrates have regions of different strengths accordingly.

The first crosslinking reaction may be performed (at least in part) prior to the second crosslinking reaction. The second crosslinking reaction can be started, for example, only when the first crosslinking reaction is finished. Alternatively, the first crosslinking reaction may be stopped before the end thereof, then the second crosslinking reaction may be performed, and the first crosslinking reaction may be continued and terminated after the end of the second crosslinking reaction.

According to the present invention, the first crosslinking reaction and the second crosslinking reaction are orthogonal to each other. Two responses orthogonal to each other are understood as responses that can be initiated or triggered (eg, thermally or photochemically) by stimuli independent of each other. Thus, the characteristic that the first crosslinking reaction and the second crosslinking reaction are orthogonal to each other is that the first crosslinking reaction and the second crosslinking reaction are initiated or triggered (eg thermally or photochemically) by stimuli independent of each other. understood to be possible. The use of reactions that are "orthogonal" to each other in a plural system is also commonly referred to as a "dual cure" mechanism in polymer chemistry.

Because the second crosslinking reaction is orthogonal to the first crosslinking reaction (ie, initiated or triggered by different stimuli), the second crosslinking reaction is independent of the first crosslinking reaction at least one desired, locally, of the silicone material. It becomes possible that it can be performed in a limited area. That is, the locally limited more extensive crosslinking achieved by the second crosslinking reaction can be performed independently of the base crosslinking achieved by the first crosslinking reaction. The crosslinking density and thus the mechanical strength within a desired locally restricted portion of the silicone material can be set as desired due to this independence. It can also be achieved that in this way a significantly higher mechanical strength can be obtained in the desired part where a more extensive crosslinking is carried out than in the remaining regions of the produced substrate. It can also be achieved that the transfer of mechanical strength between the regions of higher and lower mechanical strength is not too abrupt. Tear of the fabricated substrate at the transition point between the region of higher mechanical strength and the region of lower mechanical strength can thus be avoided, so that the fabricated substrate has significantly higher toughness and durability.

Thus, a silicon substrate or a silicon composite substrate can be produced by the method according to the invention having one or more individual locally restricted portions at a desired point of the substrate having a significantly higher mechanical strength than the remaining region or remaining regions of the substrate. have. The fabricated substrate thus provides very good adhesion and protection to the non-stretchable functional material fixed thereto due to the high mechanical strength of one or more individual desired parts, and excellent stretchability due to the lower mechanical strength of the remaining regions or of the remaining regions. , it is very suitable as a substrate for a stretchable electronic device. In addition, the fabricated substrate has significantly increased toughness and durability since the transition between regions of different mechanical strength does not occur too rapidly.

Since the silicon substrates or silicon composite substrates are made from at least one silane selected in particular from the group consisting of alkoxysilanes, hydroxysilanes, and mixtures thereof, the fabricated silicone material is a mechanical (elastomeric/thermosetting) that can be set in a structured manner. ) properties. Due to the use of at least one silane selected from the group consisting of alkoxysilanes, hydroxysilanes, and mixtures, the crosslink density in a desired locally restricted portion of the substrate and thus the mechanical strength can thus be set in a targeted manner. can be achieved

For the fabrication of materials with mechanical properties that can be set in a structured manner, elastomeric materials (eg ORMOCER ^® crosslinked with a broad mesh) in which the network density is then increased in a structured manner by locally more extensive crosslinking is manufactured first. This is done using two different orthogonal crosslinking reactions.

The substrate is thus prepared simply by the use of at least one specific silane and by carrying out two crosslinking reactions orthogonal to each other with significantly higher mechanical strength in the desired locally defined portions than in the remaining regions of the substrate. can be obtained in this way, wherein the substrates also have significantly increased toughness and durability, so that the substrates produced according to the invention are excellently suitable as substrates for stretchable electronics.

A preferred variant of the method according to the invention is characterized by:

- the first crosslinking reaction is a reaction that can be initiated thermally and the second crosslinking reaction is a reaction that can be initiated photochemically;

- The first crosslinking reaction is a reaction that can be initiated photochemically, and the second crosslinking reaction is a reaction that can be initiated thermally.

Reactions that can be thermally initiated and those that can be photochemically initiated are reactions that are orthogonal to each other. Due to the use of reactions that can be thermally initiated and reactions that can be photochemically initiated as the first crosslinking reaction and the second crosslinking reaction, thus in a simple manner, the first crosslinking, i.e. the basic crosslinking to form the silicone, and a second cross-linking, ie a more extensive cross-linking in one or more locally restricted portions of the silicone, can be achieved in a simple manner.

The reaction that can be thermally initiated is preferably selected from the group consisting of a hydrosilylation reaction, a condensation reaction, and combinations thereof.

The reaction which can be optically initiated is preferably radical polymerization, particularly preferably radical polymerization of an acrylic group, a methacryl group, or an epoxy group.

The reaction which can be initiated photochemically is preferably by irradiation with electromagnetic radiation having a wavelength in the range from 10 nm to 1000 nm, preferably by irradiation with UV light, particularly preferably by means of a sensitizer. ) by irradiation with UV light in the presence of The crosslinking reaction can be carried out in this way, particularly simply in a locally limited area. Commercially available photosensitizers (eg Irgacure ^® , Darocure ^® , Cyracure ^® ) can be used as photosensitizers.

Crosslinking of oligosiloxanes and more extensive crosslinking of silicone materials can be achieved in a simple manner by this particular type of reaction. These reaction types can also be combined with each other very easily, so that they can be carried out in succession without any problems without interfering with other crosslinking reactions.

Crosslinking to form the silicone material can be achieved, for example, with the aid of a hydrosilylation reaction or condensation reaction, and more extensive crosslinking can be achieved by radical polymerization of acrylic groups, methacryl groups, or epoxy groups.

In a further preferred variant of the process according to the invention, the first crosslinking reaction is stopped before step d) and continues after step d). The first crosslinking reaction can for example be started after step b), then still before step d), before the end of the first crosslinking reaction, ie before the start of the second crosslinking reaction, wherein the second crosslinking reaction can be stopped. After the reaction is then completely carried out, after step d), the first crosslinking reaction is continued and terminated.

A further preferred variant of the process according to the invention is characterized in that at least one silane is a compound according to the formula

wherein R is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, tolyl, vinyl, allyl, glycidyloxypropyl, (meth)acryloxypropyl, chloropropyl , aminopropyl, mercaptopropyl, is a residue selected from the group consisting of isocyanatopropyl,

R' is a moiety selected from the group consisting of H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl,

x is a number from 0 to 3.

By the use of one or more of the above special silanes, ORMOCER ^® can be obtained as (base) material of fabricated silicon substrates or silicon composite substrates. ORMOCER ^® is a hybrid material that can be prepared from one or more alkoxysilanes or hydroxysilanes of the formula R _x Si(OR') _4-x above.

Higher crosslinking (harder) substrates or lower crosslinking (softer) substrates are obtained depending on the number of alkoxy groups 4-x. The atomic group r may be unfunctionalized (methyl, ethyl, isopropyl, tert-butyl, phenyl, etc.) or functionalized (vinyl, allyl, glycidyloxypropyl, (meth)acryloxypropyl, etc.).

More extensive crosslinking of the material is possible through the above functional groups, wherein the groups are reacted with each other or with mixed crosslinking reagents (eg SiH groups of polydimethylsiloxane (PDMS) functionalized corresponding to the vinyl groups of ORMOCER ^® resins). ). The product has thermoplastic, thermoset, or elastomeric properties depending on crosslinking.

By the use of at least one silane according to the above formula R _x Si(OR') _4-x , the silicon can be made into a substrate in a particularly simple and precise manner with a crosslinking density such that the mechanical strength in localized areas can be set particularly simply and accurately. It can be obtained as a substrate material that can be established in a desired local part of

A further preferred variant of the process according to the invention is characterized in that the inorganic particles are introduced into the at least one oligosiloxane or into the silicone material before or during the first crosslinking reaction and/or before or during the second crosslinking reaction, wherein the inorganic particles are introduced into the silicone material. The particles are preferably metal nanoparticles, in particular silver nanowires and silver nanoflakes; boron nitride particles; aerosil particles; glass flakes; carbon particles, particularly conductive carbon black, carbon nanotubes, and graphene; metal oxide particles, especially ZrO ₂ , TiO ₂ , HfO ₂ and BaTiO ₃ ; and mixtures thereof. The inorganic particles may be dispersed in at least one oligosiloxane or silicone material.

The inorganic particles are included in the fabricated substrate, which may also be referred to as a silicon composite substrate. Inorganic particles affect the properties of the fabricated substrate. Metal nanoparticles, in particular silver nanowires, lead to an increase in electrical conductivity while maintaining very high transparency so that stretchable transparent electrode materials can be obtained. The boron nitride particles lead to an increase in thermal conductivity. Aerosil particles are used to improve tear resistance. A reduction in water vapor transmission rate is achieved by glass flakes. The metal oxide particles lead to, for example, an increase in the refractive index or an increase in the dielectric constant.

In a further preferred variant of the process according to the invention, the first crosslinking reaction and/or the second crosslinking reaction is carried out in the presence of a crosslinking reagent. The crosslinking reagent is preferably from the group consisting of SiH terminated polydimethylsiloxane, bis(p-dimethylsilylphenyl)ether, α,ω-diolene, α,ω-dithiolene, α,ω-diamine, and mixtures thereof. is chosen A simpler and more precisely settable crosslinking can be achieved by using a crosslinking reactant.

A further preferred variant of the process according to the invention is that the first crosslinking reaction or the second crosslinking reaction can be initiated photochemically and is preferably by irradiation with electromagnetic radiation having a wavelength in the range from 10 nm to 1000 nm. is characterized in that it is a reaction initiated by irradiation with UV light, particularly preferably by irradiation with UV light in the presence of a photosensitizer. The crosslinking reaction can be carried out particularly simply in this way. Commercially available photosensitizers (eg Irgacure ^® , Darocure ^® , Cyracure ^® ) can be used as photosensitizers.

A further preferred variant of the process according to the invention is that the second crosslinking reaction can be initiated photochemically and is by irradiation with electromagnetic radiation having a wavelength in the range from 10 nm to 1000 nm, preferably using UV light. Characterized in that the reaction is initiated by irradiation, particularly preferably by irradiation with UV light in the presence of a photosensitizer, wherein only at least one part is irradiated with electromagnetic radiation during step d), the second crosslinking reaction is thereby thus only starting from at least one portion of the silicon material. The second crosslinking reaction can be carried out in this way, particularly simply in a desired locally restricted area or areas. Commercially available photosensitizers (eg Irgacure ^® , Darocure ^® , Cyracure ^® ) can be used as photosensitizers.

It is also preferred that the portion of the silicone material in which the second crosslinking reaction is not to be carried out is covered by a mask during irradiation. Thus, it can be carried out in a very particularly simple and precise manner, in which the second crosslinking reaction is carried out only in the desired locally limited part.

The present invention also relates to a silicon substrate or silicon composite substrate comprising a silicon material, wherein the silicon substrate or silicon composite substrate can be fabricated or fabricated according to the method according to the invention.

A silicon substrate or a silicon composite substrate, due to fabrication using the method according to the present invention, comprises at least one first portion in which the silicone material has a first crosslink density and at least one second portion in which the silicone material has a second crosslink density. wherein the first crosslink density is less than the second crosslink density. wherein the at least one first part corresponds to the at least one part on which the more extensive crosslinking takes place in step d) of the process according to the invention. The silicon substrate or silicon composite substrate according to the invention now undergoes a much less abrupt transition between the at least one first part and the at least one second part, which differs from the previously known silicon substrates or silicon composite substrates. . Also, the difference between the first crosslink density and the second crosslink density is significantly greater. This difference is directly due to the fabrication using the method according to the invention.

A preferred embodiment of the silicon substrate or silicon composite substrate according to the invention is characterized in that it contains inorganic particles dispersed in a silicon material, wherein the inorganic particles are preferably metal nanoparticles, in particular silver nanowires and silver nanoparticles. flake; boron nitride particles; aerosil particles; glass flakes; carbon particles, particularly conductive carbon black, carbon nanotubes, and graphene; metal oxide particles, especially ZrO ₂ , TiO ₂ , HfO ₂ and BaTiO ₃ ; and mixtures thereof.

A further preferred embodiment of the silicon substrate or silicon composite substrate according to the present invention is that the silicon substrate or silicon composite substrate comprises at least one first portion having a first Young's modulus and at least one second portion having a second Young's modulus. wherein the first Young's modulus is greater than the second Young's modulus by a factor of 2 to 1000, preferably a factor of 10 to 1000, particularly preferably a factor of 100 to 1000. wherein the at least one first portion has a higher crosslink density than the at least one second portion. wherein the at least one first part corresponds to the at least one part on which the more extensive crosslinking takes place in step d) of the process according to the invention. Due to this significantly higher crosslink density in the at least one first portion (compared to the crosslink density in the at least one second portion), the at least one first portion also has a significantly higher crosslink density than the at least one second portion. has a Young's modulus The at least one first portion is thus significantly more rigid than the at least one second portion and is thus suitable for attachment of non-stretchable electronics functional materials (eg transistors, LEDs, etc.) on a substrate, while at least one The second part ensures the elasticity of the substrate due to its small rigidity.

For example, the first Young's modulus and/or the second Young's modulus can be determined by tensile testing with a universal tensile testing machine, for example according to ISO 527, ISO 37, or DIN 53504.

The present invention also relates to a substrate film, as an electrode, as an encapsulating material and/or as a passivation material for an electronic component such as an LED or transistor, as a dielectric in a capacitor, as a stretchable conductor path, and/or for margin stabilization of a stretchable sensor ( It relates to the use of a silicon substrate or a silicon composite substrate according to the present invention for margin stabilization.

The invention will be illustrated in more detail with reference to the following examples without limiting it to the specific embodiments and parameters shown herein.

Embodiment 1 - Preparation of Elastomer Substrate Film with Topically Reinforced Portions

STEP 1 - LIQUID ORMOCER ^® Synthesis of resin:

Individual constituents Vinyl trimethoxysilane (5.56 g, 38 mmol), vinyl methyldimethoxysilane (52.89 g, 400 mmol), diphenyldimethoxysilane (122.18 g, 500 mmol), and methacryloxypropylmethyldimethoxy The silanes (73.65 g, 313 mmol) are mixed together. 21.6 g of 0.5 N-HCl are added dropwise and heating takes place in an oil bath at 80° C. bath temperature for 24 hours. The mixture is then taken up with 750 ml of ethyl acetate and extracted 5 times in each case with 313 ml of water. The organic phase is dried using sodium sulfate, filtered and the solvent is removed on a rotary evaporator. A viscous ORMOCER ^® resin is obtained.

Step 2 - Elastomer ORMOCER ^® Synthesis of the film:

60 g of resin obtained after step 1 had 50.6 g of AB 109364 (SiH terminated PDMS, ABCR corporation) and 1.1 g of Karstedt catalyst solution (0.1% in xylol) and stirred. Toluol is added with stirring to the cloudy mixture until clear, and 1.2 g of a UV starter Darocur 1173 is then dissolved therein. Then, 47.9 Aerosil particles (type R8200, Evonik corporation) are added and the mass is homogenized in a speed mixer. The mass is spread on a carrier to form a layer, and an elastomeric film is obtained after heat treatment in a drying cabinet (12 hours at 80° C.).

Step 3 - Creation of thermoset regions in the elastomeric film:

The film is irradiated with UV light through a mask (Karl Suss MA6 Mask Aligner, 20 mW/cm ² , Hg lamp; 280-450 nm). The methacrylic groups contained in the material are thereby crosslinked - excited by the UV starter - which gives an increase in Young's modulus in the exposed region from 1.5 MPa to 20 MPa.

Embodiment 2

Step 1 - Liquid ORMOCER as Electrode Matrix ^® Synthesis of resin:

Individual Ingredients Vinyl trimethoxysilane (3.34 g, 22.5 mmol), vinyl methyldimethoxysilane (31.74 g, 240 mmol), diphenyldimethoxysilane (36.65 g, 150 mmol), dimethyldimethoxysilane (9.02 g, 75 mmol) and epoxycyclohexylethylmethyldimethoxysilane (60.48 g, 262.5 mmol) are mixed with each other. 265.8 Diethyl carbonate is added and stirring is done at room temperature. Then, 0.278 g of an aqueous ammonium fluoride solution is added dropwise, and stirring is performed at room temperature for 3 days. The solvent is removed on a rotary evaporator. A viscous ORMOCER ^® resin is obtained.

Step 2 - Preparation of Silver Nanowire Dispersion:

Silver nanowire synthesis was performed in a polyol method modified according to Sun et al. (Y. Sun, Y. Yin, BT Mayers, T. Herrics, Y. Xia, Chem. Mater. 2002, 14, 4736-4745). made by 5.31 g of PVP (MW = 55,000, 0.0966 mmol) is dissolved in 115.19 g of dry ethylene glycol and heated to 140° C. in a 3-neck flask. Then, 865 μl of 0.22 M NaCl solution and 240 μl of 0.2 mM Fe(NO ₃ ) ₃ · 9 H ₂ O-solution are added and stirred for 5 minutes. A solution of 1.09 g (6.42 mmol) of AgNO ₃ is now added dropwise to 28.82 g of ethylene glycol. The mixture is heated to 135-145° C. for 90 minutes, then cooled and mixed with 100 ml of ethanol. The obtained suspension was redispersed in ethanol which was repeatedly centrifuged at 2000 rpm to remove Ag nanoparticles.

Step 3 - Fabrication of the electrically conductive structure:

1 g of resin obtained after step 1 has 0.36 g of bis(p-dimethylsilylphenyl)ether and 0.0136 g of Karstedt catalyst solution (0.1% in xylol) mixed and stirred. 0.03 g of UV starter Cyracure UVI 6974 are then dissolved in the clear mixture and stirring is done overnight. Then, dilution with ethyl acetate is made in a ratio of 1:10, and mixing with 3% by volume of ethanolic silver nanowire dispersion (from step 2) is made. An elastomeric substrate (made according to embodiment 1) is coated with this mixture (centrifugal coating, 2000 rpm, 20 seconds). After the first 1 minute heat treatment (“prebake”) at 100° C., which should limit the flowability of the material but does not impair its solubility in organic solvents, the reinforced conductive structure is exposed to UV light by means of a chromium metallization correction mask. (Karl Suss MA6 Mask Aligner, 20 mW/cm ² , Hg lamp: 280 - 450 nm). After an additional 1 minute thermal step at 100° C. (“post-exposure bake”), development, i.e., washing with isopropanol, of the non-UV-exposed regions of the material containing Ag nanowires Removal takes place The remaining film is finally thermally vulcanized to form an elastomer, and the Ag nanowires disposed on the surface are removed with the aid of an etchant (HCl/HNO ₃ /H ₂ O 1:1:1). The conductivity of the electrode thus prepared reaches 5.5 Ω/□.

Claims (15)

A method of manufacturing a silicon substrate or a silicon composite substrate, comprising:
a) providing at least one silane selected from the group consisting of alkoxysilanes, hydroxysilanes, and mixtures thereof;
b) at least one liquid oligosiloxane is prepared by a sol-gel reaction from at least one silane;
c) performing a first crosslinking reaction wherein at least some crosslinking of the at least one liquid oligosiloxane is performed to form a silicone material;
d) at least one portion of the silicone material is subjected to a second crosslinking reaction in which a more extensive crosslinking of the silicone material is carried out;
The method of claim 1, wherein the first crosslinking reaction and the second crosslinking reaction are orthogonal to each other. According to claim 1,
- said first crosslinking reaction is a reaction which can be initiated thermally and said second crosslinking reaction is a reaction which can be initiated photochemically; or
- the first crosslinking reaction is a reaction which can be initiated photochemically and the second crosslinking reaction is a reaction which can be initiated thermally. The method of claim 2 , wherein the thermally initiable reaction is selected from the group consisting of a hydrosilylation reaction, a condensation reaction, and combinations thereof. The process according to claim 2 or 3, wherein the photochemically initiable reaction is radical polymerization. 5. The method according to any one of claims 1 to 4, wherein the first crosslinking reaction is stopped before step d) and continues after step d). 6. The compound according to any one of claims 1 to 5, wherein the at least one silane is a compound according to the formula

wherein R is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, tolyl, vinyl, allyl, glycidyloxypropyl, (meth)acryloxypropyl, chloropropyl , aminopropyl, mercaptopropyl, is a residue selected from the group consisting of isocyanatopropyl,
R' is a residue selected from the group consisting of H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl,
x is a number from 0 to 3. 7. The method according to any one of claims 1 to 6, wherein inorganic particles are introduced into the at least one liquid oligosiloxane or into the silicone material before or during the first crosslinking reaction and/or before or during the second crosslinking reaction, The inorganic particles here are preferably metal nanoparticles, in particular silver nanowires and silver nanoflakes; boron nitride particles; aerosil particles; glass flakes; carbon particles, particularly conductive carbon black, carbon nanotubes, and graphene; metal oxide particles, especially ZrO ₂ , TiO ₂ , HfO ₂ and BaTiO ₃ ; and mixtures thereof. 8. The crosslinking reaction according to any one of the preceding claims, wherein the first crosslinking reaction and/or the second crosslinking reaction is carried out in the presence of a crosslinking reactant, the crosslinking reactant preferably being a SiH terminated polydimethyl siloxane, bis(p-dimethylsilylphenyl)ether, α,ω-diolene, α,ω-dithiolene, α,ω-diamine, and mixtures thereof. 9. Irradiation with electromagnetic radiation according to any one of claims 1 to 8, wherein the first crosslinking reaction or the second crosslinking reaction can be initiated photochemically and has a wavelength in the range of 10 nm to 1000 nm. A method, wherein the reaction is initiated by, preferably by irradiation with UV light, particularly preferably by irradiation with UV light in the presence of a sensitizer. 10. The method according to claim 9, wherein the second crosslinking reaction can be initiated photochemically and by irradiation with electromagnetic radiation having a wavelength in the range from 10 nm to 1000 nm, preferably by irradiation with UV light. is a reaction initiated by irradiation with UV light, particularly preferably in the presence of a photosensitizer,
wherein during step d) only the at least one part is irradiated with electromagnetic radiation and the second crosslinking reaction is thus initiated exclusively on the at least one part of the silicone material. 11. The method of claim 10, wherein the portion of the silicone material in which the second crosslinking reaction is not to be performed is covered by a mask during the irradiation. 12. A silicon substrate or silicon composite substrate comprising a silicon material, wherein the silicon substrate or silicon composite substrate is fabricated or can be fabricated according to the method according to any one of claims 1 to 11. 13. The method according to claim 12, comprising inorganic particles dispersed in the silicon material, wherein the inorganic particles are preferably metal nanoparticles, in particular silver nanowires and silver nanoflakes; boron nitride particles; aerosil particles; glass flakes; carbon particles, particularly conductive carbon black, carbon nanotubes, and graphene; metal oxide particles, especially ZrO ₂ , TiO ₂ , HfO ₂ and BaTiO ₃ ; and a silicon substrate or a silicon composite substrate selected from the group consisting of mixtures thereof. 14. The method of claim 12 or 13, wherein the silicon substrate or silicon composite substrate comprises at least one first portion having a first Young's modulus and at least one second portion having a second Young's modulus;
A silicon substrate or a silicon composite substrate, wherein the first Young's modulus exceeds the second Young's modulus by a factor of 2 to 1000, preferably a factor of 10 to 1000, particularly preferably a factor of 100 to 1000. As a substrate film, as an electrode, as an encapsulating material and/or as a passivation material for an electronic component (such as an LED or transistor), as a dielectric in a capacitor, as a stretchable conductor path, and/or as a stretchable conductor path, and/or of a stretchable sensor. Use of a silicon substrate or a silicon composite substrate according to any one of claims 12 to 14 for edge stabilization.