METHOD FOR FORMING A CRACK IN THE EDGE REGION OF A DONOR SUBSTRATE, USING AN INCLINED LASER BEAM

Abstract

The invention relates to a method for separating solid-body slices (1) from a donor substrate (2). The method comprises the following steps: providing a donor substrate (2), producing at least one modification (10) within the donor substrate (2) by means of at least one LASER beam (12), wherein the LASER beam (12) penetrates the donor substrate (2) via a planar surface (16) of the donor substrate (2), wherein the LASER beam (12) is inclined with respect to the planar surface (16) of the donor substrate (2) such that it penetrates the donor substrate at an angle of not equal to 0? or 180? relative to the longitudinal axis of the donor substrate, wherein the LASER beam (12) is focused in order to produce the modification (10) in the donor substrate (2) and the solid-body slice (1) detaches from the donor substrate (2) as a result of the modifications (10) produced or a stress-inducing layer (14) is produced or arranged on the planar surface (16) of the donor substrate (2) and mechanical stresses are produced in the donor substrate (2) by a thermal treatment of the stress-inducing layer (14), wherein the mechanical stresses produce a crack (20) for separating a solid-body layer (1), which crack propagates along the modifications (10).

Claims

1. A method for separating solid-body layers, in particular solid-body slices (1), from a donor substrate (2), said method comprising at least the following steps: providing a donor substrate (2), producing at least one modification (10) within the donor substrate (2) by means of at least one LASER beam (12), wherein the LASER beam (12) penetrates the donor substrate (2) via a planar surface (16) of the donor substrate (2), wherein the LASER beam (12) is inclined relative to the planar surface (16) of the donor substrate (2) in such a way that it penetrates the donor substrate (2) at an angle of not equal to 0? or 180? relative to the longitudinal axis of the donor substrate, wherein the LASER beam (12) is focused in order to produce the modification (10) in the donor substrate (2), wherein the solid-body slice (1) detaches from the donor substrate (2) as a result of the produced modifications (10) or a stress-inducing layer (14) is produced or arranged on the planar surface (16) of the donor substrate (2) and mechanical stresses are produced in the donor substrate (2) by a thermal treatment of the stress-inducing layer (14), wherein the mechanical stresses produce a crack (20) for separating a solid-body layer (1), which crack propagates along the modifications (10).

2. The method according to claim 1, characterised in that a first portion (36) of the LASER beam (12) penetrates the donor substrate (2) at a first angle (38) to the planar surface (16) of the donor substrate and at least one further portion (40) of the LASER beam (12) penetrates the donor substrate (2) at a second angle (42) to the planar surface (16) of the donor substrate (2), wherein the value of the first angle (38) differs from the value of the second angle (42), wherein the first portion (36) of the LASER beam (12) and the further portion (40) of the LASER beam (12) are focused in order to produce the modification (10) in the donor substrate (2).

3. The method according to claim 2, characterised in that the totality of the LASER beams (12) is oriented in the same orientation relative to the planar surface (16) of the donor substrate (2) for the production of modifications (10) in the region of the centre (Z) of the donor substrate (2) and for the production of modifications (10) in the region of an edge (44) of the donor substrate (2) provided in the radial direction, in particular at a distance of less than 10 mm and preferably less than 5 mm and particularly preferably less than 1 mm from the edge.

4. The method according to claim 2 or 3, characterised in that the first portion (36) of the LASER beams (12) penetrates the donor substrate (2) at a first angle (38) to the planar surface (16) of the donor substrate (2) and the further portion (40) of the LASER beams (12) penetrates at a second angle (42) for the production of modifications (10) in the region of the centre (Z) of the donor substrate (2) and for the production of modifications (10) in the region of an edge (44) of the donor substrate (2) provided in the radial direction, wherein the value of the first angle (38) always differs from the value of the second angle (42).

5. The method according to any one of preceding claims 1 to 4, characterised in that wherein the LASER beams (12) are emitted from a LASER device (46), wherein the LASER device (46) is a picosecond LASER or a femtosecond LASER, and/or the energy of the LASER beams (12), in particular of the fs-LASER, is selected in such a way that the propagation of damage of each modification (10) in the donor substrate (2) is less than 3 times the Rayleigh length, preferably less than the Rayleigh length, and particularly preferably less than a third of the Rayleigh length and/or the wavelength of the LASER beams (12), in particular of the fs LASER, is selected in such a way that the absorption of the donor substrate (2) is less than 10 cm.sup.?1 and preferably less than 1 cm.sup.?1 and particularly preferably less than 0.1 cm.sup.?1 and/or the individual modifications (10) are produced in each case as a result of a multi-photon excitation brought about by the LASER beams (12), in particular of the fs LASER.

6. The method according to claims 1 to 5, characterised in that the LASER beams (12) for production of the modifications (10) penetrate the donor wafer (2) via a surface (16) that is part of the solid-body slice (1) to be separated.

7. The method according to any one of the preceding claims, characterised in that the LASER beam (12) penetrates the donor substrate (2) via a peripheral surface of the donor substrate (2), in particular in the radial direction of the donor substrate (2).

8. The method according to claim 7, characterised in that the LASER beams (12) introduced into the donor substrate (2) via the peripheral surface produce modifications (10) that are elongate, in particular filament-like, and/or the LASER beams (12) introduced at a position of the peripheral surface of the donor substrate (2) are focused at different penetration depths in order to produce a plurality of modifications (10), wherein the modifications (10) are preferably produced starting from the deepest depth towards the shallowest depth.

9. The method according to either one of claim 7 or 8, characterised in that a means for aberration adjustment is provided and an aberration adjustment is produced by the means at the LASER beams penetrating via the peripheral surface.

10. The method according to any one of the preceding claims, characterised in that the stress-inducing layer (14) comprises a polymer, in particular polydimethylsiloxane (PDMS), or consists thereof, wherein the thermal treatment is performed in such a way that the polymer experiences a glass transition, wherein the stress-inducing layer (14) is temperature-controlled, in particular by means of liquid nitrogen, to a temperature below room temperature or below 0? C. or below ?50? C. or below ?100? C. or below ?110? C., in particular to a temperature below the glass transition temperature of the stress-inducing layer (14).

Description

[0038] Further advantages, objectives and properties of the present invention will be explained on the basis of drawings accompanying the following description, in which the solutions according to the invention are illustrated by way of example. Components or elements or method steps of the solutions according to the invention which in the figures coincide at least substantially in terms of their function can be denoted here by the same reference signs, wherein these components or elements do not have to be provided with reference signs or explained in all figures.

[0039] In the drawings:

[0040] FIG. 1 shows an example of an edge treatment within the scope of the solid-body slice production or solid-body layer production according to the invention;

[0041] FIG. 2 shows a further example of an edge treatment within the scope of the solid-body slice production or solid-body layer production according to the invention;

[0042] FIG. 3 shows an illustration that shows the problems that occur with the production of modifications in a solid body if the modifications are produced by means of LASER beams;

[0043] FIG. 4 shows an illustration that shows the various LASER beam angles;

[0044] FIGS. 5a/5b show an illustration of a modification production step and a schematic illustration of the produced modifications;

[0045] FIGS. 6a/6b show two illustrations of modification production steps; and

[0046] FIG. 7 shows production of a modification with an aberration adjustment; and

[0047] FIG. 8 shows a schematic illustration of a solid body that has indentations covered or superimposed or closed by a stress-inducing layer.

[0048] FIG. 1 shows 4 illustrations. In the first illustration of FIG. 1 a donor substrate 2 is shown that is exposed to LASER beams 12. The LASER beams 12 are inclined in their totality relative to the surface 16 via which the LASER beams penetrate the donor substrate 2, in such a way that the inclination differs from an angle of 90?. A first portion 36 of LASER beams 12 is preferably oriented relative to the surface 16 at a first angle 38, and a further portion 40 of LASER beams 12 is oriented relative to the surface 16 at a second angle 42. The LASER beam portions 36 and 40 are preferably always inclined identically relative to the surface 16 via which the LASER beam portions 36, 40 penetrate the donor substrate 2, preferably so as to produce all modifications 12 produced for separating a certain solid-body layer 1. It can also be deduced from the first illustration of FIG. 4 that the focus point 48 for producing modifications 10 can be guided in the donor substrate 2 as far as the edge 44 or directly as far as the edge 44 on account of the inclined LASER beam portions 36, 40.

[0049] Illustration 2 of FIG. 1 also shows that, in accordance with the LASER beam portions 36, 40 oriented in an inclined manner, a material-removing treatment of the edge 44 of the donor substrate 2 is not necessary or is only necessary to a significantly reduced extent. The stress-inducing layer arranged or produced on the surface 16 generates mechanical stresses in the donor substrate 2, whereby a crack 20 propagates in the donor substrate 2 in a manner guided very precisely from the edge 44 on account of the modifications 10 produced as far as the edge 44.

[0050] Illustration 3 of FIG. 1 shows a solid-body slice 1 completely split off from the donor substrate 2, wherein the solid-body slice 1 preferably has not experienced any edge treatment in accordance with this embodiment.

[0051] Illustration 4 of FIG. 1 shows that a solid-body slice 1 can be removed from the donor substrate 2 likewise by producing modifications 10 by means of LASER beams 36, 40 (without a stress-inducing layer 14).

[0052] The present invention thus relates to a method for separating solid-body slices 1 from a donor substrate 2. The method according to the invention comprises the following steps:

[0053] providing a donor substrate 2, producing modifications 10 within the donor substrate 2 by means of LASER beams 12, wherein the LASER beams 12 penetrate the donor substrate 2 via a planar surface 16 of the donor substrate 2, wherein the totality of LASER beams 12 is inclined relative to the planar surface 16 of the donor substrate 2 in such a way that a first portion 36 of the LASER beams 12 penetrates the donor substrate 2 at a first angle 38 relative to the planar surface 16 of the donor substrate 2 and at least one further portion 40 of the LASER beams 12 penetrates the donor substrate 2 at a second angle 42 relative to the planar surface 16 of the donor substrate 2, wherein the value of the first angle 38 differs from the value of the second angle 42, wherein the first portion 36 of LASER beams 12 and the further portion 40 of LASER beams 12 are focused in order to produce the modification 10 in the donor substrate 2, wherein the solid-body slice 1 detaches from the donor substrate 2 as a result of the modifications 10 produced or a stress-inducing layer (14) is produced or arranged on the planar surface (16) of the donor substrate (2) and mechanical stresses are produced in the donor substrate (2) by a thermal treatment of the stress-inducing layer (14), wherein the mechanical stresses produce a crack (20) for separating a solid-body layer (1), which crack propagates along the modifications (10).

[0054] FIG. 2 shows a further variant of the method according to the invention. By means of a comparison of the first and fifth illustration, it can be seen that the modifications 10 produced by means of the LASER beams 12, in the case of a planar surface 16, can be produced closer to the edge 44 than if the tip of the edge 17 of the surface 16 is removed, as shown in the fifth illustration. The LASER beams 12 here penetrate the donor substrate 2, similarly to the modification production explained with reference to FIG. 1.

[0055] The second illustration of FIG. 2 shows the production of an indentation 6 starting from a peripheral surface 4 in the direction of the centre Z of the donor substrate 2, wherein the indentation is produced by means of ablation LASER beams 8 of an ablation LASER (not shown). The ablation LASER beams 8 here preferably evaporate the material of the donor substrate 2 in order to produce the indentation 6.

[0056] According to illustration 3 of FIG. 2 the form of the indentation is not asymmetrical, but instead is symmetrical. In accordance with this illustration as well, a stress-inducing layer 14 is produced or arranged on the donor substrate 2 and is thermally treated, in particular by means of liquid nitrogen, in order to produce mechanical stresses for initiating a crack 20.

[0057] Illustration 4 of FIG. 2 shows the solid-body slice 1 split off from the donor substrate 2, with the stress-inducing layer still arranged on said solid-body slice.

[0058] It can also be seen from illustration 5 of FIG. 2 that in the case of a donor substrate 2 of which the tip of the edge 17 is processed, the indentation 6 to be produced by means of ablation LASER beams 8 must reach further in the direction of the centre of the donor substrate 2 than if the tip of the edge 17 is not processed. Here, however, it is also conceivable that the indentation is not produced by means of ablation LASER beams 8, but instead by means of a grinding tool 122 (as is known for example from FIG. 1).

[0059] FIGS. 3a and 3b show a problem in the edge region of the donor substrate 2 occurring with the production of modifications by means of LASER beams 12. By means of the different refractive indices in the air and in the donor substrate, the LASER beam portions 38, 40 of a LASER beam 12 do not coincide exactly with one another, thus resulting in undesirable effects, such as the production of defects at undesirable locations, an undesirable local heating, or a prevention of the production of a modification.

[0060] FIG. 3b shows that a problem-free production of modifications 10 can be provided only if the modification 10 to be produced is distanced from the peripheral surface of the donor substrate 2 to such an extent that both LASER beam portions 38, 40 are each refracted through material with the same refractive index and preferably over the same distance. However, this means that the production of the modification, as it occurs in the region distanced from the edge region, cannot be readily extended to the edge region.

[0061] FIG. 4 shows an arrangement in accordance with which a LASER beam 12 is oriented parallel to the longitudinal axis L. This illustration additionally or alternatively also shows a LASER beam 60 inclined at an angle ?1 relative to the longitudinal axis L. Both LASER beams 12 and 60 can serve here for the production of the modifications 10, by means of which a detachment region 11 is predefined. It is conceivable here that a plurality of the modifications 10 are produced by the LASER beam 12, which is not inclined relative to the longitudinal axis L, and that the modifications 10 in the edge region, that is to say at a distance of less than 10 mm, in particular of less than 5 mm or of less than 2 mm or of less than 1 mm or of less than 0.5 mm from the peripherally extending surface (peripheral surface), are produced by the LASER beam 60 inclined relative to the longitudinal axis L.

[0062] Alternatively, it is also conceivable that all modifications 10 of the detachment region or the plurality of modifications 10 of the detachment region 11 are produced by the LASER beam 60 inclined at an angle ?1 relative to the longitudinal axis L.

[0063] Additionally or alternatively, within the sense of the present invention, the modifications 10 in the edge region can be produced by a further LASER beam 62, 64 inclined relative to the longitudinal axis L of the donor substrate 2, wherein this LASER beam preferably penetrates the donor substrate 2 over a peripheral surface of the donor substrate 2. It can be seen from the illustration that a LASER beam 62, for production of the modifications 10 in the edge region, can be introduced into the donor substrate 2 over the peripheral surface for example at an angle ?2, which is greater than 0? and smaller than 90?, relative to the detachment region 11. It can also be seen from the illustration that a LASER beam 64, in order to produce the modifications 10, can be introduced into the donor substrate 2 over the peripheral surface of the donor substrate 2 in the direction of extent of the detachment region 11. Here, the LASER beam 64 is preferably inclined at an angle ?3, between 80? and 100?, in particular 90? or substantially 90?, relative to the longitudinal axis L of the donor substrate 2.

[0064] A modification 10 can thus be produced in the region of the edge by one of the LASER beams 60, 62, 64.

[0065] Furthermore, in accordance with the invention, the statements provided with reference to FIG. 1 can be applied or transferred similarly to the subjects shown in FIG. 4, and vice versa.

[0066] FIG. 5a shows a detachment region 11 produced just short from the edge region. FIG. 5a also shows the production of modifications by means of a LASER beam 64. A plurality of modifications 10 are preferably produced in the radial direction by the LASER beam 64, in particular over a line, with increasingly greater distances from the centre or an axis of rotation (which extends preferably orthogonally to the planar surface 16 of the donor substrate 2) of the donor wafer 2.

[0067] FIG. 5b schematically shows a state following the production of the modifications 10. In accordance with this illustration the detachment region 11 is formed as a modification layer extending completely within the donor wafer 2.

[0068] FIGS. 6a and 6b show two variants for producing modifications 10 by means of LASER beams introduced over the peripheral surface.

[0069] In accordance with FIG. 6a, a multiplicity of modifications 10 are produced over the same penetration point, through which the LASER beams 64 penetrate the donor substrate 2. The LASER beams are focused into the donor substrate 2 at different depths in the radial direction in order to produce the modifications 10. The modifications 10 are preferably produced with decreasing penetration depth of the LASER beams or with increasingly shorter distance of the focus point from the penetration point.

[0070] FIG. 6b shows the filament-like production of modifications. The modifications 10 produced in the form of filaments are longer then a multiple of their cross-sectional extent, in particular for example 10 times, 20 times, or 50 times longer.

[0071] FIG. 7 shows a LASER device 46, an aberration means 47, and a sectional illustration of a donor substrate 2. The detailed illustration of FIG. 7 shows the LASER beam 12 penetrating the donor wafer 2 over the curved peripheral surface of the donor wafer 2, wherein the course of the radiation adapted by means of the aberration means 47 is illustrated by the dashed lines.

[0072] The present invention therefore relates to a method for separating solid-body slices 1 from a donor substrate 2. The method according to the invention comprises the following steps: providing a donor substrate 2, producing at least one modification 10 within the donor substrate 2 by means of at least one LASER beam 12, wherein the LASER beam 12 penetrates the donor substrate 2 over a planar surface 16 of the donor substrate 2, wherein the LASER beam 12 is inclined relative to the planar surface 16 of the donor substrate 2, in such a way that it penetrates the donor substrate at an angle that is unequal to 0? or 180? relative to the longitudinal axis of the donor substrate, wherein the LASER beam 12 is focused in order to produce the modification 10 in the donor substrate 2, wherein the solid-body slice 1 detaches from the donor substrate 2 by the produced modifications 10 or a stress-inducing layer 14 is produced or arranged on the planar surface 16 of the donor substrate 2 and mechanical stresses are produced in the donor substrate 2 by a thermal treatment of the stress-inducing layer 14, wherein a crack 20 for separating a solid-body layer 1 is produced by the mechanical stresses and propagates along the modifications 10.

[0073] FIG. 8 schematically shows an arrangement in accordance with which the stress-inducing layer 14 preferably superimposes or covers or closes at least one indentation 6, in particular a recess or hollow cavity, which extends preferably starting from a planar or substantially planar surface 16 in the direction of a further surface of the solid body 2, which further surface is preferably parallel to the planar surface 16.

[0074] The stress-inducing layer 14 is preferably produced as a polymer layer or is produced as a layer that consists predominantly in terms of proportions by mass and/or proportions by volume of at least one polymer material. The surface 16 on which the stress-inducing layer 14 is arranged preferably has treated portions. Here, treated portions is preferably understood to mean portions in which material has been removed. One or more indentations, in particular recesses 6 and/or hollow cavities 6, thus preferably extend preferably orthogonally to the surface and/or the crack-forming layer, starting from the surface 16 on which the stress-inducing layer 14 is arranged and which preferably extends substantially or completely parallel to a crack-forming layer formed from modifications 10. Here, it is alternatively conceivable that only one indentation 6, in particular a hollow cavity and/or a recess, has been produced and/or is formed by means of material removal. The material removal is preferably performed, in particular by means of laser ablation, before the production or attachment of the stress-inducing layer 14 on the surface 16. The stress-inducing layer 14, in the state coupled or connected to the solid body 2, covers the indentation(s) 6, in particular the hollow cavity or the hollow cavities or the recess or the recesses.

[0075] There is preferably no further coating, in particular no further material application, between the production of the indentation 6, in particular the recess and/or the hollow cavity, and the attachment of the stress-inducing layer. This is advantageous since otherwise material could accumulate in the recess/hollow cavity.

[0076] The stress-inducing layer is preferably attached by means of a plasma lamination process. This is advantageous since a connection between the solid body 1, in particular the main surface 16 of the later solid-body layer 1, and the stress-inducing layer 14 can thus be produced over the indentation 6, in particular recess/hollow cavity. The connection is preferably a lamination or adhesive bonding. It is preferably implemented with use of cold plasma.

[0077] Additionally or alternatively, a spontaneous split with previously produced laser plane or crack-forming plane and depth modification can be brought about in accordance with the invention by a material removal step, in particular laser ablation. This is preferably implemented without stress-inducing layer 14.

[0078] The stress-inducing layer 14 can also be referred to as a stressor layer, in particular as a self-supporting stressor layer.

[0079] In accordance with the invention it has also been found that a self-supporting stressor layer is of significant technical advantage compared to a stressor layer applied by vapour deposition or applied by some other form of deposition, since stressor layers of this kind can be produced on the one hand in larger volume in simpler methods in specialised facilities with a higher throughput and on the other hand can be used in lamination processes, which likewise allow quicker process speeds. In addition, self-supporting stressor layers can also be removed again from the substrate following lamination processes, even with little effort, which for example also allows re-use, i.e. of the stressor layer or of the stress-inducing layer, which is not possible with deposited layers.

[0080] It is particularly advantageous that lamination processes can also be performed without adhesive bonding methods or the like purely by a surface activation, surface treatment, or surface modification of the substrate. A coupling or connection of the stress-inducing layer to the solid body, in particular to the surface 16 of the later solid-body layer 1, is thus achieved particularly preferably by a surface activation and/or surface treatment and/or surface modification of the solid body or the surface 16 of the later solid-body layer 1.

[0081] For example, the surface can preferably be activated by contact with, in particular in a chamber, produced ozone and/or by ultraviolet light of a certain wavelength and/or by plasma methods with different formed species on the surfaces of the substrate and/or the stressor layer and/or in the process gas, in particular radical aldehyde and alcohol species. Here, hot plasma methods are preferred in particular, in which high temperatures are used in order to produce free charge carriers and radicals in the plasma, which, for the subsequent reactions at the surfaces of substrate and stressor layer, allows other reaction paths and chemical surface reactions compared to lower temperatures. The surface modification mechanism can thus differ in a temperature-dependent manner, also between various substrates, wherein for example in the case of SiC, compared to Si, the carbon atoms involved can form different surface species in the plasma treatment which can likewise have an adhesion-promoting effect in the lamination process.

[0082] Alternatively, the use of a cold plasma method is possible, in which a plasma is not produced by thermionic emission or via hot tungsten filaments or similar methods, but instead via piezoelectric transformers at atmospheric pressure and preferably without elevated temperatures. These lower temperatures likewise reduce and/or change the available reaction paths for surface activations and surface modifications for adhesion promotion in lamination processes, both at the substrate or the solid body and at the stressor layer. The resultant surface species are thus dependent on a multiplicity of parameters and the surface activation method in particular.

[0083] The surface treatment or modification for example comprises the exposure, at least in portions, of the surface to be treated by a corona treatment and/or a flame treatment and/or a treatment by means of electrical barrier discharge and/or fluorination and/or by ozonisation and/or by excimer irradiation and/or by a treatment with a plasma, wherein individual or a plurality of physical parameters, such as the type of plasma, the path distance during the plasma treatment, the nozzle type, the nozzle distance and/or the duration of the plasma treatment, are preferably varied or can be varied.

[0084] A plasma pre-treatment or plasma treatment is preferably used both for cleaning and then for homogenisation of the surface species (for example hydrophobising, amongst others).

[0085] A spatially resolved variation of the surface activation can be produced or adjusted by means of a selective individual plasma treatment and then allows a lamination of the stressor layer, likewise with different properties in different areas, if desired.

[0086] The process of the plasma surface activation or of the plasma surface treatment allows a greater influencing in order to apply the desired differentiated adhesion or force transfer after the lamination of the stressor layer on the substrate also over large areas in a defined symmetrical or asymmetrical form. Here, by means of process variation, an amended adhesion or cohesion can be set, in particular locally. Depending on the starting properties of the different solid-body materials, in particular semiconductor materials, layers can be applied and/or the desired auxiliary layer(s), in particular sacrificial/damage layers or substrate and/or stressor layer surfaces, can be selectively modified (hydrophobic, hydrophilic, wetting, etc.) by further gradual process gases (oxygen, amongst others). This leads to a spatially resolved, adapted gradual adhesion or spatially resolved adapted or adjusted force transfer connection, also in lamination processes, which is only homogeneous and not spatially resolved compared to that by adhesive bonding and deposition solutions for the stressor layer.

[0087] As already described, different physical parameters can be used during the plasma treatment (for example plasma type, path distance during the plasma treatment, nozzle type, nozzle distance, duration of the plasma treatment). In addition to these influencing parameters, a greater bandwidth of the necessary surface properties can be provided by selective admixing of gradual process gases, such as nitrogen, oxygen, hydrogen, SiH4, Si(EtO)4 or Me3SiOSiMe3 (amongst others). These result preferably from new chemical surface species, which deposit themselves on the semiconductor surface and/or the adjoining sacrificial layers and/or the stressor layer and thus enable a different surface functionality and lamination process properties. This leads to the desired target profiles, for example different spatially resolved adhesion and cohesion properties, of the semiconductor surfaces and/or the adjoining stressor and/or other layers.

[0088] A corona treatment is an electrochemical method for surface treatment or modification of plastics. Here, the surface is exposed to an electric high-voltage discharge. A corona treatment is used for example to promote adhesion in plastics and films, amongst others (PE, PP).

[0089] In the case of a flame treatment a surface-near oxidation of the respective compounds takes place in particular. In principle, oxidation processes are performed, by means of which different polar functional groups are formed (for example oxides, alcohols, aldehydes, carboxylic acids, esters, ethers, peroxides) depending on the material and test conditions.

[0090] A treatment by dielectric barrier discharge (DBE, AC voltage gas discharge, also DBD treatment) is similar to a low-temperature plasma or glow discharge (for example GDMS). In the case of DBE treatment the surface is acted on by unipolar or bipolar pulses with pulse durations of a few microseconds down to tens of nanoseconds and amplitudes in the single-digit kilovolt range. A dielectric barrier discharge is advantageous since no metal electrodes are anticipated in the discharge chamber, and therefore no metal contaminations or electrode wear is anticipated.

[0091] Further advantages of the dielectric barrier discharge, depending on application, for example can be that it has a high efficiency, since no charge carriers have to exit or enter at the electrodes (omission of the cathode drop, no glow emission necessary), or that the dielectric surfaces can be modified and chemically activated at low temperatures. The surface modification is performed here preferably by an interaction and reaction of the surface species by ion bombardment and the effect of ultraviolet radiation on the surface species (for example 80 nm-350 nm, incoherent UV and VUV light, by high-frequency power generators). The dielectric barrier discharge is used for example for in situ production of ozone in drinking water/wastewater treatment, wherein the water is ozonised by the ozone. Similarly, in the case of a surface treatment or modification according to the invention by means of ozonisation, the surface to be treated is acted on by ozone.

[0092] A surface treatment or modification by means of halogenation, in particular fluorination, causes an element or a compound to be converted into a halide. By means of the fluorination, fluorine is thus introduced into preferably organic compounds with the aid of fluorinating agents.

[0093] A surface treatment or modification by means of UV treatment is performed preferably by excimer irradiation or by ultraviolet light-emitting diode sources, for example based on aluminium nitride. Excimer irradiation is performed by the use of at least one excimer LASER. Excimer LASERs are gas LASERs which can generate electromagnetic radiation in the ultraviolet wavelength range. A gas discharge occurring in this case is thus caused by an electromagnetic high-frequency field. There is thus also no need for any electrodes for the gas discharge. The produced UV radiation lies preferably in a wavelength range between 120 nm and 380 nm.

REFERENCE LIST

[0094] 1 solid-body slice [0095] 2 donor substrate [0096] 4 surface extending in the peripheral direction [0097] 6 indentation [0098] 8 ablation LASER beams [0099] 10 modifications [0100] 12 further LASER beams [0101] 14 stress-inducing layer [0102] 16 planar surface [0103] 17 edge [0104] 18 indentation end [0105] 20 crack [0106] 22 grinding tool [0107] 24 first processing portion [0108] 26 second processing portion [0109] 28 underside [0110] 30 upper side [0111] 32 main grinding face [0112] 34 secondary grinding face [0113] 36 first portion of LASER beams [0114] 38 first angle [0115] 40 further portion [0116] 42 second angle [0117] 44 edge [0118] 46 LASER device [0119] 48 LASER focus