DE102010027438B4 - Process for producing a connection point and/or a connection area in a substrate, in particular for improving the wetting and/or adhesion properties of the substrate - Google Patents

Abstract

Method for producing a connection point and/or a connection area on and/or in a surface (1a) of a substrate (1), wherein on and/or in the surface (1a) of the substrate (1) a preferably periodic deep structure ( 2) leading material removal takes place before the deep structure (2) introduced into the surface (1a) of the substrate (1) is then at least partially filled with a mediator material (3) suitable for materially bonded connection, the mediator material (3) being an adhesion promoter material or a laminating material and the mediator material (3) is introduced into the deep structure (2) by free-falling droplet application, screen printing, stamp application, needle application, brush application, spatula application, doctor blade application, spraying, spraying, pouring and/or rolling, and the material is removed by means of laser interference, in that at least one laser beam (4) is radiated through a microlens array (5) and thereby divided into several individual beams (4a, 4b, ...), which are focused on a flat focal surface (6) and by the surface (1a) seen in the laser beam direction behind the microlens array (5) is positioned at a predefined position in front of the focal surface (6), behind the focal surface (6) or in the focal surface (6), or the material is removed by means of laser interference, in that several coherent laser beams (4a, 4b, ...) are applied in an overlapping area (U) are made to interfere at predefined angle(s) and by positioning the surface (1a) at a predefined position in this overlapping area (U), thereby separating the plurality of laser beams (4a, 4b,...) by means of at least one beam splitter (10a, 10b, ...) from a single laser beam (4) emitted by a laser and guided into the superimposition area (U) using at least one beam deflector (11a, 11b, ...).

Description

The present invention relates to a method for producing a connection point and/or a connection area on and/or in a surface of a substrate. The substrate can be any material whose wetting and/or adhesion properties are to be improved.

Laser pre-treatment of surfaces for subsequent bonding or lamination using one-dimensional or two-dimensional laser scanner technology in combination with focusing optics is known from the state of the art: The laser beam scans the surface quasi-simultaneously and hits it perpendicularly or below, depending on the optics a position-dependent, variable angle, on the sample surface.

The disadvantage here is that the scanning leads to an irregular energy input, which in turn leads to structures of different depths and/or undefined patterns of the deep structure introduced into the sample surface. In addition, the laser scanner methods have a high heat input into the processed sample material.

In addition, it is known from the prior art to change the topography of a sample surface by sandblasting with corundum. If silica-modified corundum is used, a SiO _x layer is deposited in addition to roughening the surface.

The DE 101 05 893 A1 relates to a method for producing composite bodies by joining, in which microstructured recesses are to be formed on surfaces by laser radiation.

A similar joining process is out U.S. 2008/0 213 612 A1 known. It specifies different parameters for laser radiation, with which an influencing of a microstructuring to be formed can be achieved.

The FR 2 796 388 A1 also relates to a method in which surfaces are to be structured by means of laser radiation, among other things.

A particular disadvantage here is that an additional cleaning process (which then also has to be carried out before and after the sandblasting) is necessary. The sandblasting also leads to inhomogeneities in the surface or in the depth structuring of this surface that is achieved, since uniform processing is difficult to control. In addition, corundum blasting is unsuitable for thin parts to be joined and cannot be integrated into production lines.

By M. Campbell et al. in "Fabrication of photonic crystals for visible spectrum by holographic lithography"; Nature; Vol. 404; 2000, pages 53-56 known possibilities for the production of photonic crystals using laser radiation.

Possibilities and advantages for the formation of microstructures using laser interference are mentioned in general terms by M. Bieda in "Production of periodic microstructures on metal surfaces; Fraunhofer Annual Report 2009, pages 26-27.

DE 10 2009 060 924 A1 relates to a structure containing a solid lubricant and a manufacturing method for such structures.

The diploma work of AF Lasagni; "Advanced design of periodical structures by laser interference metallurgy in the micro/nano scale on microscopic areas", Saarland University; Saarbrücken 2006. URL: https://publikationen.sulb.uni-
Saar-
land.de/handle/20.500.11880/22418;jsessionid=F4DD18AE791B14E791B14E7 A9035FD890720863 describes possibilities for laser interference structuring.

The basics of interference can be found in Interference (Physics). In: Wikipedia, the free encyclopedia. Editing status July 13, 2010, 22:13 UTC, URL: https://de.wikipedia.org/w/index.php?Title=Interferenz_(Physik)&oldid=76637143.

Eichler J et al. offer an overview of possible laser processing in "designs, beam guidance; applications. 6th edition, Springer-Verlag Berlin Heidelberg; 2006, p. 368 - ISBN 3-540-30149-6.

Standing on conditions for maintaining coherence WM et al. In Laser Material Processing. 4th edition, Springer-Verlag London, 2010; pp. 54-55 , pp. 98-99 and p. 381-ISBN 978-1-85996-061-8.

Based on the prior art, it is therefore the object of the present invention to provide a method for producing a connection point and/or a connection area and/or a method for connecting a material (hereinafter also referred to as substrate) with another material (hereinafter also referred to as with element to be provided on the substrate or as a laminating material to be bonded to the substrate

(Laminating layer) called) to make available, which leads to an improvement in the wetting and / or adhesion properties of the material and / or between the material and the element to be disposed of with this material or the laminating material and with which a high-strength connection between a for connecting suitable intermediary material to be applied to the substrate (which is an adhesion promoter material or else a material to be laminated to the substrate) and the substrate surface and/or between the substrate and an element to be provided with it. With the method according to the invention, when using the mediator material suitable for connecting, improved adhesive or laminating behavior and a high-strength connection between the materials involved (substrate, adhesion promoter material and element or substrate and mediator material in the form of a laminating material to be disposed of with the substrate) are to be achieved.

The object of the invention is also to provide a corresponding substrate with a connection point and/or a connection area and a component with a substrate and an element provided with this substrate or with a material laminated onto the substrate.

The above object is achieved by a manufacturing method according to claim 1. Advantageous design variants can be found in the dependent claims.

The entire following description of the invention is given for a method for producing a connection point and/or a connection area in the form of a joint or a joint area, in which the deep structure produced (see below) is at least partially bonded with an adhesion promoter material (adhesive material) suitable for materially bonded joining. is filled as mediator material. However, exactly the same procedure can be implemented according to the invention for forming a connection point or a connection area as a laminating point or laminating area: In this case, the deep structure is filled with a laminating material instead of an adhesion promoter material or adhesive material.

Materials other than adhesive or laminating materials that are suitable for connecting can also be introduced into the deep structure.

All of the features described below according to the invention for the joining are thus also disclosed according to the invention for the application of a laminating material or a laminating layer to the deep-structured substrate. The only difference is that only the laminating material is filled into the deep structure of the substrate as an intermediary material (and is usually also applied as a flat laminating layer, for example): In this case, only two different materials (substrate material and laminating material) are used. required, the further material (additional element) still required during joining (in addition to the substrate material and the adhesion promoter or adhesive material) to be disposed of with the substrate is then omitted.

In the context of the following description of the invention, the adhesion-promoting material is alternatively referred to as an adhesive, although it can generally be any material that, after being applied and/or introduced onto and/or into the surface of the substrate, is used to form a material-to-material connection of the Substrate or its surface is suitable with the element to be provided with it.

In the following, the invention is first described in general terms, then with reference to exemplary embodiments. The individual features described in combination with one another in the context of the exemplary embodiments do not have to be implemented exactly in the configurations shown in the examples, but can also be implemented in other types of combinations within the scope of the present invention. In particular, individual method steps described in the exemplary embodiments can also be omitted.

The basic idea of the present invention is based on using laser interference to structure the surface of the substrate, i.e. to create a deep structure extending from the surface into the depth of the substrate (by means of laser-induced material removal) and then to materially join the substrate with a other material suitable adhesion promoter material to introduce into the depressions of the deep structure. As a rule, these indentations are structures in the size of a micrometer, so that the terms microindentations or microstructures are alternatively also used below.

According to the invention, a flat or also pre-contoured (e.g. curved) surface of the substrate (or also of the substrate and the element to be joined with it; both surfaces of the joining materials to be joined can therefore also be treated accordingly) by direct laser beam interference and/or by Use of microlens arrays (see also below) and using pulsed or continuous laser radiation in the UV range, in the visible range and/or in the infrared range, structured with a micrometer or sub-micrometer structure.

The (deep) structured joining materials (substrate and/or element) can be plastics, in particular fiber-reinforced plastics, ceramics, metals or alloys. However, the area of use of the present invention is not limited to the materials mentioned.

After the deep structuring of the surface of the substrate (or both joining materials), the adhesion promoter material (application of adhesive) suitable for the materially bonded joining is applied for the subsequent materially bonded joining process. Depending on which adhesion promoter material is used, time restrictions may have to be observed, which make it necessary to join the two joining materials within a predefined time interval.

Adhesive systems based on polyaddition (e.g. epoxides, polyurethanes and/or silicones), polycondensation (formaldehyde, polyamides and/or silicones), polymerisation (e.g. acrylates or rubber polymers or also thermoplastic elastomers) as well as physically setting systems (hot melt adhesives, e.g. Polyolefins) are used. The adhesive systems mentioned must be mixed, dosed and applied accordingly, i.e. introduced into the depressions, which can necessitate different process steps depending on the adhesion promoter materials used: Depending on the adhesion promoter materials and/or also on the specific adhesive geometry of the substrate and/or element, the following are required Methods used and the mediator material introduced into the deep structure according to the invention: free-falling droplet application, screen printing method, stamp application, needle application, application by brush, spatula and / or scraper, spraying, spraying, pouring and / or rolling. The curing conditions (temperature, use of UV radiation if necessary, ...) of the adhesion promoter materials used depend on the crosslinking mechanisms of these materials.

A method according to the invention for producing joining areas on surfaces of substrates thus comprises a first step in which material is removed from this surface on and/or in the surface of the substrate by means of a laser beam interference method by laser irradiation of the surface of the substrate, which a deep structuring of this surface. Such a deep structure is understood to mean the incorporation of generally micrometer to submicrometer sized structures, such as trenches or holes, into the generally formerly (at least locally) flat surface of the substrate. Periodic deep structures are preferably introduced.

Then, in a second step, the adhesion promoter material suitable for material-to-substance joining is introduced into the deep structure introduced into the surface. Depending on the number, position, size and/or shape of these depressions and/or the shape of the surface before their deep structuring, the individual depressions of the deep structure do not necessarily all and/or have to be completely filled with the adhesion promoter material; if necessary, a partial amount is sufficient fill off.

In a first advantageous variant of the method, the laser light used for laser beam interference is radiated onto the surface of the substrate with locally varying laser light intensity in such a way that locally varying material removal leads to the formation of a large number of individual depressions in the deep structure.

In a further advantageous variant, the laser interference irradiation can take place by radiating one or more laser beam(s) through one or more microlens array(s) and thereby dividing it (in each case) into a number of individual beams. These individual rays are then on
focused on a focal area. The surface of the substrate to be structured is then arranged at a predefined position behind the microlens array(s), seen in the direction of the laser beam: This position can be in front of the focus area, in the area of the focus area or behind the focus area, with preference being given to positioning the surface of the substrate takes place in the focal area.

Alternatively, or with a suitable arrangement of the individual system elements in combination with it, the laser interference-induced material removal can also take place as follows: Several coherent laser beams are brought to interference in an overlapping area at a predefined angle(s). In this case, the substrate surface is positioned at a predefined position in this overlapping area. The multiple laser beams can be generated from a single laser beam emitted by a single laser by means of one or more beam splitter(s) and guided into the overlapping area using beam deflectors such that interference of these laser beams occurs in this overlapping area.

The deep structure introduced into the substrate surface or its individual depressions can be one- or two-dimensional periodic structures. The for the distances between the individual depressions, the periodicity of the deep structure, the depth of the individual depressions (perpendicular to the substrate surface), their lateral extent in the substrate surface and / or the aspect ratios (e.g. in the case of periodically introduced linear trenches with ridges remaining between them) are advantageous realizable orders of magnitude can be found in the dependent claims.

• • linienartige Muster mit periodischem Abstand d,
• • kreuzartige Muster, die durch Mehrfachbestrahlung mit Linienmustern mit einem spezifischen Rotationswinkel von beispielsweise 30°, 60° oder 90° erreicht werden,
• • kombinierte kreuzartige Muster mit unterschiedlichen Linienabständen d₁ und d₂,
• • verschiedene Anordnungen von Vertiefungen (Löchern) mit unterschiedlichen Abständen,
• • praktisch beliebige Formen von Vertiefungen, die mittels Mikrolinsenarrays über der Probe eingebracht werden können,
• • praktisch beliebige Formen von Vertiefungen, die über eine Verschiebung der Probe während der Laserbestrahlung durch ein/mehrere Mikrolinsenarray(s) eingebracht werden können,
• • praktisch beliebige Formen von Vertiefungen, die durch eine Verschiebung der Bestrahlungsoptik während der Bestrahlung mittels eines Mikrolinsenarrays einstrukturiert werden können,
• • linienartige Muster, die über Mikrolinsenarrays eingebracht werden können,
• • kreuzartige Muster, die durch eine Mehrfachbestrahlung mit Linienmustern mit Mikrolinsenarrays erzeugt werden können, oder
• • beliebige Kombinationen der vorstehend aufgezählten Varianten.

In particular, the deep structures introduced by laser interference can include the following variants:

• • line-like patterns with periodic spacing d,
• • cross-like patterns, which are achieved by multiple irradiation with line patterns with a specific rotation angle of, for example, 30°, 60° or 90°,
• • combined cross-like patterns with different line spacings d ₁ and d ₂ ,
• • different arrangements of indentations (holes) with different distances,
• • practically any shape of indentations that can be introduced over the sample using microlens arrays,
• • practically any shape of indentations that can be introduced by moving the sample during laser irradiation through one or more microlens array(s),
• • practically any shape of depressions that can be structured by shifting the irradiation optics during the irradiation using a microlens array,
• • line-like patterns that can be introduced via microlens arrays,
• • Cross-like patterns that can be generated by multiple irradiation with line patterns using microlens arrays, or
• • Any combination of the variants listed above.

The laser irradiation can be pulsed or continuous, it being possible for laser wavelengths in the visible, in the infrared and/or in the ultraviolet range to be used. Nd:YAG-pulsed lasers with wavelengths of 266 nm or 355 nm are particularly preferably used.

The decisive advantage of the present invention lies in the introduction of a precise periodic micrometer or sub-micrometer structure, which, in combination with the surface enlargement achieved by introducing the structure and the subsequent application of the adhesion promoter material (adhesive), results in an optimized joining process can.

The laser beam interference allows the processing of all types of surfaces and component geometries under natural environmental conditions. It enables the production of precisely defined periodic micro- or sub-micron structures in a single process step. The high resolution that can be achieved is superior to other commercially used microstructuring processes.
The direct laser interference structuring method according to the invention (without using microlens arrays) is also characterized in particular by the fact that large areas can be structured on almost any material in a short time. No other process produces such a homogeneous and defined structured pattern on a part surface. The surface embossing or structuring according to the invention by laser interference can effectively improve the adhesive layer morphology and the structure-dependent mechanical behavior of the substrate and/or element to be provided with it.

The laser beam interference method according to the invention for component pretreatment for the subsequent introduction of the adhesion promoter material, ie for the actual joining, also allows a very small joining or adhesive gap. With low-viscosity adhesives, the surface structures created can also interlock extremely effectively.

The present invention also includes the use of the method according to the invention described above in the field of medical technology, optics, sensor technology and in areas in which surface distortions and undefined amounts of adhesive have a decisive negative influence on the overall system. In addition, applications of the methods described are also possible, particularly in other high-tech areas, such as in the area of electronics or in the area of aircraft construction.

The production method according to the invention and substrates and components according to the invention formed by it are described below with reference to several exemplary embodiments.

• 1 eine Skizze für ein Substrat mit Fügebereich, das erfindungsgemäß herstellbar ist.
• 2 verschiedene Tiefenstrukturformen (nachfolgend alternativ auch als Vertiefungsstrukturformen bezeichnet) der vorliegenden Erfindung.
• 3 eine Mikrolinsen-Array-Konfiguration zur Ausführung eines erfindungsgemäßen Herstellungsverfahrens.
• 4 verschiedene Mikrolinsen-Arrays für den Aufbau gemäß 3.
• 5 einen direkten Laser-Interferenz-Strukturierungsaufbau für ein Herstellungsverfahren gemäß der vorliegenden Erfindung in Zwei-Strahl-Konfiguration.
• 6 einen entsprechenden Aufbau wie in 5 in Drei-Strahl-Konfiguration.
• 7 einen entsprechenden Aufbau wie in 5 in Vier-Strahl-Konfiguration.
• 8 eine Prinzipskizze zur erfindungsgemäßen Erzeugung einer Vertiefungsstruktur in einer Substratbasis durch ein Herstellungsverfahren gemäß 5 bis 7.
• 9 ein erfindungsgemäßes Bauteil bestehend aus einem Substrat mit Fügebereich und einem mit diesem Substrat verfügten Element.

Show it:

• 1 a sketch of a substrate with a joining area that can be produced according to the invention.
• 2 various depth structure forms (hereinafter also alternatively referred to as recess structure forms) of the present invention.
• 3 a microlens array configuration for carrying out a manufacturing method according to the invention.
• 4 different microlens arrays for the structure according to 3 .
• 5 a direct laser interference patterning setup for a manufacturing method according to the present invention in two-beam configuration.
• 6 a corresponding structure as in 5 in three-beam configuration.
• 7 a corresponding structure as in 5 in four-beam configuration.
• 8th a schematic diagram for the inventive production of a recess structure in a substrate base by a manufacturing method according to 5 until 7 .
• 9 a component according to the invention consisting of a substrate with a joining area and an element provided with this substrate.

1 shows the structure of such a substrate in a cross section perpendicular to the layer plane S of a substrate 1 produced according to the invention. The substrate here is a flat copper plate with a thickness of 5 mm, which is to be bonded to another element with high strength.

As with regard to the 3 until 8th is described in detail below, the substrate, which is still flat, is first laser structured, in which a locally varying intensity input (seen in the layer plane S of the substrate 1) is realized in a surface 1a of the substrate 1 by the fact that this surface 1a is provided with a large number of individual Laser (part) rays is irradiated. The laser intensity is regulated in such a way that material is removed from the surface 1a or in the substrate 1 locally at the point at which the individual laser beams impinge.

The intensity of the laser beams (Nd:YAG pulsed laser with a frequency tripled wavelength of 355 nm) is increased by superimposing several beams ( 3 until 8th ) adjusted in such a way that the individual depressions 2a, 2b, is removed (e.g. evaporated or melted).

By checking the angle of incidence β of, for example, two laser beams ( 5 ) the periodicity p of the interference pattern can be varied (seen in the layer plane S). In this way, a large number of individual, rectilinear trenches running parallel to one another and at constant distances d from one another are formed as depressions 2a, 2b, . . . in the surface 1a. The distance d between adjacent trenches (ie the periodicity p of the one-dimensional depression structure 5 produced) is approximately 15 μm here. The trench width produced in the layer plane S and perpendicular to the longitudinal axes of the trench is approximately l=7.5 μm. This results in an aspect ratio A=h/l=5/7.5. However, instead of the trenches, columns or holes or hole patterns can also be structured as depressions.

After the laser structuring of the surface 1a, the substrate 1 with the deep structure 2 is subjected to a screen printing process in order to deposit the adhesive material 3 in the depressions 2a, 2b produced. In the present case, an epoxy material suitable for gluing the Cu plate 1 is pressed into the depressions 2a, 2b, .

2 FIG. 1 shows various periodic depression structures 3, which can be formed in the surface 1a by laser structuring and running parallel to the layer plane S. So shows 2a) a one-dimensional depression structure 2 in the form of a trench structure G1, in which a multiplicity of parallel trenches run at a distance from one another. The distance d between immediately adjacent trenches or the periodicity p in the direction R1 perpendicular to the longitudinal axes of the trench can be between 0.2 μm and 100 μm, for example.

2 B) shows a superimposition of two such trench structures at an angle α ≠ 0° (here: α = 70°): For example, the first trench structure G1 (trench spacing d1) can be produced in direction R1 using a cylindrical lens microlens array before the substrate 1 is rotated by α, in order to then, by renewed laser irradiation through the cylindrical lens microlens array (or with a line-like interference pattern), the second trench structure G2 (trench spacing d2) in direction R2 (which is then rotated by α in relation to direction R1). generate.

2c ) shows the case 2 B) , in which α=90°, that is to say two trench structures G1, G2 (crossed grating) which are aligned perpendicularly to one another and are formed in the substrate surface 1a.

2d ) shows an example in which the depression structure 2 is not formed in the form of one or more trench structure(s), but rather comprises a multiplicity of individual holes 2a, 2b, . . . . The holes are arranged at the crossing points of a square grid, resulting in a two-dimensional periodicity of the depression structure in two mutually perpendicular directions R1 and R2 (the hole spacing or hole period d1 in direction R1 and the hole spacing or hole period d2 in direction R2 are identical here). For example, d1=d2=20 μm and a hole diameter l in the layer plane of 5 μm and a hole depth h perpendicular to the layer plane of 5 μm are chosen.

2e) shows another case of a periodic hole structure as in 2d ), but here the two directions R1 and R2, in which the individual holes are arranged in rows at periodic intervals, are not perpendicular to one another, but form an angle of α = 70°.

3 shows a first structure for producing a substrate 1 according to the invention with a joining region 2, 3 introduced into its surface 1a. The structure includes a laser (not shown), for example a UV-emitting laser with a wavelength of λ=266 nm. The laser beam 4 of this laser is here in pulsed form (however, a continuous laser beam can also be generated, the element 13 is then omitted) first by a device 13 for controlling the number of pulses, here a mechanical shutter, radiated. A homogenizer 14 is arranged behind the mechanical shutter 13 in the beam path of the laser beam 4 . The homogenizer consists of a system of optical elements that generate, for example, a top-hat beam profile. In the beam path 4 behind the homogenizer 14 there is a telescope system 15 for checking or adjusting a desired beam diameter. This is followed in the beam path 4 by a diaphragm (here: iris diaphragm) or else a rectangular diaphragm 16 before the laser beam 4 finally strikes a microlens array 5 . The aperture 16 is used to bring the beam outline and beam diameter of the laser beam 4 to a predetermined shape (eg, rectangular) and size. The order of components 13 to 16 can also differ from that in 3 shown can be selected. If necessary, the elements 13 to 16 can be omitted.

The microlens array 5 is here a cylindrical lens microlens array with a multiplicity of cylindrical lenses arranged in a plane parallel to one another and at constant distances from one another (the longitudinal axes of which are arranged here perpendicular to the plane shown). The individual cylindrical lenses of the microlens array 5 have a focal distance f. The laser beam 4 is thus divided into a large number of individual partial beams 4a, 4b, 4c, ... by the microlens array 5, which are at a distance f behind the microlens array 5 are focused on a flat surface 6.

With the aid of a displacement table 17 that can be moved in the three translation directions x, y and z of a Cartesian coordinate system, the substrate 1 is now aligned in such a way that the surface 1a to be structured (cf. 1 ) is aligned parallel to the focal surface 6. In the case shown, the surface 1a and the focal surface 6 coincide, so that the partial beams 4a, 4b, . . . are focused onto this surface (focal distance f equals distance a of the array 5 from the surface 1a). By suitably selecting the beam parameters of the laser beam 4, the above-described indentation structures 2 are thus produced in the substrate 1 at the point of incidence of the partial beams 4a, 4b, .

The distance a between the microlens array 5 and the substrate base 1 can be changed to adjust the structure size of the depression structure 2: By moving the substrate base 1 using the displacement table 14 in the +z direction, the focal plane 6 is displaced behind the surface 1a into the interior of the substrate 1 ; depressions 2a, 2b, . . . are then produced with an increased lateral extent l. The same happens with a method in the −z direction, since the focal plane 6 then lies outside of the substrate 1 and in front of it. In order to regulate the structure size of the depression structure, the distance a can thus be selected to be larger or smaller than the focus distance f. In addition, it is possible to produce different indentation structure geometries with a controlled size by translating the substrate 1 in the x and/or y direction using the displacement table 17 .

A robot can also be used instead of a translation table (with or without a rotary axis). Here, both the components 5 and 13 to 16 and the substrate base 1 can be coupled to the displacement table and/or robot. When arranging the components 5 and 13 to 16 on a corresponding displacement table or robot, it is advantageous to use fiber-coupled lasers.

4a) outlines once again how the structure size that is structured into layer 3 can be changed by changing the distance a relative to the focal distance f (varying the distance between the surface 1a and the microlens array). 4b) to f) shows that different microlens arrays can be used: line-generating microlens arrays with cylindrical ( 4b) ) microlenses, point-generating microlenses with crossed cylindrical ( 4c )) microlenses, with hexagonal ( 4d )) or quadratic ( 4e) ) Lens assemblies and square microlens arrays ( 4f) ). All of these microlens arrays 5 from the 4b) until 4f) can therefore im in 3 structure shown can be used.

When in the 3 and 4 The structure shown can be used with different laser wavelengths. For pulsed lasers (with pulse lengths eg in the nanosecond, picosecond or femtosecond range), various processes such as ablation, melting, phase transformation, local hardening etc. can be achieved when forming the depression structure 2 in the surface 1a. Direct surface modifications with a laser pulse are also possible. The number of laser pulses can be varied to control the shape and depth of the surface modifications 2. The laser intensity can also be varied in order to obtain different geometries of the modifications 2.

5 shows a structure for direct laser interference structuring for the production of the deep structure 2 of a substrate 1, 2, 3 according to the invention prepared for joining. A pulsed laser beam 7 with a predefined intensity is first applied by a device 13 for controlling the number of pulses (here: mechanical Shutter) (alternatively, a continuous laser beam can also be used, in which case the device 13 can optionally be omitted). A homogenizer (here: a cylindrical or rectangular screen) 14 is arranged in the beam path after the device 13 . The laser beam leaving the homogenizer is radiated via a telescope system 15, with which the beam diameter is brought to a predefined, desired size (eg 5 mm). The telescope system 12 is followed by a diaphragm (eg, iris diaphragm) or square diaphragm 16 to arrive at a predefined, desired shape (eg, rectangular) and beam size, and set a predefined beam profile. In the beam path after the aperture 16 follows a first, here also a single beam splitter 10a, with which the laser beam 4 is split into two partial beams 4a and 4b. The first partial beam 4a is deflected via two beam deflectors arranged in its beam path in the form of mirrors 11a and 11b and finally radiated onto the surface 1a (not shown here) at a predefined angle. The substrate base 1 is here, similar to in 3 shown, arranged on a translation table 17. The second partial beam 4b leaving the beam splitter 10a is deflected by a further mirror 11c and is also radiated onto the surface 1a at a defined angle. The two aforementioned angles of incidence of the two partial beams 4a and 4b are designed such that the two partial beams converge at an angle β of, for example, 40° and cross or overlap in an overlapping region U. In this overlapping area U, in which the two partial beams 4a, 4b intersect, ie overlap, the substrate 1 is arranged, in whose surface the depression structure 2 is to be introduced. The angle β between the two laser beams 4a, 4b can be varied in order to produce structures of different periodicity.

With the aid of the displacement table 17, the substrate 1 can be displaced so that large, level and non-level (e.g. cylindrical) surfaces can be deeply structured 2 . The displacement can be orthogonal to the main beam axis (e.g. lateral or vertical), or parallel to the main beam axis and/or consist of a rotation of the element 1. The lateral extent l and/or the depth h of the structures 2 can be adjusted via the beam intensity, irradiation duration and/or number of pulses.

8th outlines the overlapping area U 5 in detail: Both beams 4a, 4b superimposed at the angle β form an interference pattern (standing wave structure) in the superimposition region U, in which the surface 1a is arranged, at the maxima of which a periodic deep structuring 2 of the substrate 1 takes place (at There is no deep structuring at the nodes of the interference structure between the maxima, since the incident intensity is lower here (possibly also zero)).

The in the 5 and 8th The direct laser beam interference structuring method shown thus enables the production of periodic two-dimensional or three-dimensional microstructuring on all types of substrates and component geometries to be prepared for joining. In order to generate an interference structure, N (with N ≥ 2) collimated and coherent laser beams 4a, 4b, ... are superimposed on or below a surface 1a. This results in particular in the advantage that both flat and non-flat, curved surfaces can be structured, since the interference takes place in the entire overlapping volume of the individual partial beams 4a, 4b, .

6 and 7 show two additional setups for direct laser interference structuring. These are basically like the one in 5 shown structure, so that only the differences are described below: When in 6 The structure shown is a three-beam structure in which two beam splitters 10a, 10b placed one behind the other in the beam path of the laser beam 4 result in a splitting into three Individual partial beams 4a, 4b and 4c takes place, which are then radiated onto the surface 1a from three different directions, ie at different angles, with the aid of corresponding mirrors 11a to 11d. The three partial beams 4a to 4c thus also overlap in a superimposition area U in which the substrate 1 is arranged.

7 shows a corresponding four-beam arrangement in which beam 4 is split into a total of four different partial beams 4a to 4d via three beam splitters 10a to 10c arranged one behind the other in the beam path of laser radiation 4, which in turn are split by means of differently arranged and aligned beam deflectors 11a to 11e are radiated from four different directions onto the surface 1a arranged in the superimposition area U. Here, too, all four individual beams 4a to 4d cross or overlap in the overlapping area U.

9 1 shows a component produced according to the invention, in which a substrate 1 provided with a joining area 2, 3 on its surface 1a has been provided with a further element E.

The substrate 1 is a flat plastic plate (before deep structuring), which is screwed onto a metal base 1b here. After the introduction of a one-dimensional, periodic deep structure in the form of parallel trenches 2a, 2b, ..., with a constant trench spacing d between adjacent trenches (corresponding to the periodicity p of the deep structure 2), an acrylate-based adhesion promoter material 3 in the trenches 2a, 2b, ... incorporated. The trenches were completely, i.e. over their entire height h, and also filled with adhesion promoter material 3, so that on the side opposite the metal plate 1b or on the surface 1a of the substrate 1 there is also a thin, closed adhesive layer 3 trains.

Finally, the further element E to be joined to the substrate 1, which is another flat plastic plate, is placed parallel to the surface 1a or to the layer plane S on the adhesion promoter layer 3 and pressure-pressed with the elements 1, 1b.

Claims (8)

Method for producing a connection point and/or a connection area on and/or in a surface (1a) of a substrate (1), wherein material is removed on and/or in the surface (1a) of the substrate (1) by means of laser interference, leading to a preferably periodic deep structure (2), before the deep structure (2) introduced into the surface (1a) of the substrate (1) is at least partially filled with a mediator material (3) suitable for the material connection, wherein the mediator material (3) is an adhesion promoter material or is a laminating material and the mediator material (3) is introduced into the deep structure (2) by free-falling droplet application, screen printing, stamp application, needle application, brush application, spatula application, doctor blade application, spraying, spraying, pouring and/or rolling and the material is removed by means of laser interference, in that at least one laser beam (4) is radiated through a microlens array (5) and thereby divided into several individual beams (4a, 4b, ...), which are focused on a flat focal surface (6) and in that the Surface (1a) seen in the laser beam direction is positioned behind the microlens array (5) at a predefined position in front of the focus area (6), behind the focus area (6) or in the focus area (6). or the material is removed by means of laser interference, in that several coherent laser beams (4a, 4b, ...) are brought to interference in a superimposition area (U) at a predefined angle(s) and in that the surface (1a) is at a predefined position in this overlapping area (U) is positioned, and the multiple laser beams (4a, 4b, ...) are generated by means of at least one beam splitter (10a, 10b, ...) from a single laser beam (4) emitted by a laser and using at least one beam deflector (11a, 11b , ...) into the overlapping area (U). Method according to the preceding claim, characterized in that the material is removed by means of laser interference, in that laser light (4) with laser light intensity that varies locally as seen in and/or tangentially to the surface (1a) is irradiated onto the surface (1a) in such a way that and/or locally varying material removal in the surface (1a) leads to the formation of depressions (2a, 2b, ...) of the deep structure (2). procedure after claim 1 or 2 , characterized in that the at least one laser beam (4), which is radiated through a microlens array (5) and divided into a plurality of individual beams (4a, 4b, ...) which are focused on a flat focal surface (6), and by the surface (1a) seen in the direction of the laser beam behind the microlin senarray (5) is positioned at a predefined position in the focus area (6). Method according to one of the preceding claims, characterized in that on and/or in the surface (1a) there is a deep structure (2) which is periodic in one direction (R1) or in two directions which are at an angle (α) of unequal 0° to one another (R1, R2) periodic deep structure (2), is formed, and / or that a plurality of depressions (2a, 2b, ...) of the deep structure (2) is formed so that the distance d (d1, d2) adjacent Depressions (2a, 2b, ...) and/or a periodicity p of the deep structure (2) in and/or tangentially to the surface (1a) is between 100 nm and 500 µm, so that the depth h of the depressions (2a, 2b, ...) perpendicular to the surface (1a) and/or a tangential surface thereof between 1 µm and 500 µm, that the lateral extension 1 of the depressions (2a, 2b, ...) in and/or tangential to the surface (1a) is between 1 μm and 500 μm, and/or that the aspect ratio A=h/l of the above depth extension h and the above lateral extension l is between 0.05 and 10, preferably between 0.3 and 3. Method according to the preceding claim, characterized in that the periodic depth structure (2) is a trench structure (G1) comprising a multiplicity of individual linear trenches running parallel to one another and each with a constant trench spacing (d, d1) from one another, or two such trenches under one Angle (α) of intersecting trench structures (G1, G2) with the same or different trench spacings (d1, d2) is formed, and/or that a multiplicity of holes (2a, 2b, ...) having a periodic hole structure is formed, the holes of this hole structure being formed in two directions (R1, R2) at periodic distances (d1, d2) to one another at an angle (α) of not equal to 0°. Method according to one of the preceding claims, characterized in that the laser irradiation takes place in a pulsed or continuous manner and/or with at least one laser wavelength in the visible, in the infrared and/or in the ultraviolet range and/or that the substrate (1) is made of plastic, of fiber-reinforced plastic , consists of ceramic and/or metal or comprises at least one of the aforementioned materials and/or that the mediator material (3) comprises a material suitable for promoting adhesion by means of polyaddition, by means of polycondensation and/or by means of polymerisation and/or an epoxide, a polyurethane, a silicone, a formaldehyde, a polyamide, an acrylate, a rubber polymer and/or a thermoplastic elastomer. Method according to one of the preceding claims, characterized in that a joint or a joint area is produced as the connection point or area by the deep structure (2) being at least partially filled with an adhesion promoter material suitable for materially bonded joining as the promoter material (3), or that as a Connection point or area a laminating point or a laminating area is produced by the deep structure (2) being at least partially filled with a laminating material as an intermediary material (3). Method according to the preceding claim, characterized in that the surface (1a) of the substrate (1) and/or the adhesion promoter material (3) at the joint and/or the joint area after the deep structure has been filled with the adhesion promoter material (3) with a surface section of an element (E) to be provided with the substrate (1) is/are brought into contact for joining the substrate to this element (E).

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