DE102016003556A1 - Combined laser treatment of a solid to be split - Google Patents

Abstract

The present invention relates to a method for separating at least one solid layer (14) from a solid body (1), wherein by the modifications (2) a crack guide region (4) for guiding a crack for separating a solid portion (6), in particular one Solid state layer, from the solid state (1) is specified. Preferably, the present invention comprises at least the steps of: moving the solid (1) relative to a laser applying means (8), sequentially generating laser beams (10) by means of the laser applying means (8) for generating at least one modification (2), the laser applying means (8) for the defined modification generation as a function of at least one parameter, in particular the transmission of the solid at defined locations and for a defined solid body depth is set, wherein the adjustment of the laser application device (8) inhomogeneities of the solid (1) in the region of the applied surface and / or in the region of the charged volume of the solid (1), separating the solid layer (14) from the solid (1).

Description

The present invention according to claims 1, 7, 12, 14, 17 and 19 respectively relates to a method for separating at least one solid layer from a solid and according to claim 5 to a method for producing at least one at least partially curved or curved solid layer ,

Semiconductor materials are z. B. grown in large cylinders of crystalline material, so-called ingots, while industrial processes often require wafer material with different thickness and surface quality. Wafering of brittle semiconductor materials is often performed with diamond or slurry-based wire sawing processes. These sawing processes not only result in kerf loss of potentially valuable material, but also surface roughness and underneath the surface to damage the crystal. These wafer sawing processes require the necessary polishing and grinding steps in the wafer manufacturing process, resulting in additional damage and process costs.

To address these problems in conventional wafering and thinning of semiconductors, so-called kerf-less technologies have been developed which promise a reduction in kerf losses, if not elimination, as well as under surface damage and grinding process steps. In particular, externally applied so-called spalling processes use to separate stress - often temperature-related - crystalline materials along crystal planes of well-defined thickness. Spalling can be done with nickel-chromium alloys, silver-aluminum paste, epoxy resin, aluminum and nickel. Kerf-free wafering techniques have the potential to drastically reduce damage in semiconductor manufacturing processes. Stress-based separation techniques, such as spalling, use externally applied stresses to separate crystalline materials along their crystal planes of well-defined thickness. Substrates show after spalling, however, so-called Wallner lines, which originate from the crack propagation in the crystal.

Spalling was made possible using differences in thermal expansion coefficients between a brittle material and a polymer adhering to the surface of the material. Cooling the bonded materials below the glass transition temperature of the polymer induces stresses that result in material separation along a cracking plane. An advantage of this particular method, as opposed to other types of spalling, is that the process of cooling does not cause increased diffusion of unwanted chemical components through the material, as opposed to high temperature processes also used for spalling.

However, spalling processes tend to be limited in their control over the wafer thickness achieved, and tuning the vertical location of the crack propagation is complicated. In addition, spalling produces very prominent patterns of Wallner lines on the surface. This pattern consists of strip-shaped grooves and elevations, which originate from the crack propagation in the semiconductor material and allow a derivation of the crack dynamics in the substrate. Usually, the crack begins at the edge at some point and then spreads rapidly from the edge of the substrate. Wallner lines of conventional spalling surfaces greatly increase the resulting surface roughness, often to the point where additional polishing or grinding steps are required prior to further processing and fabrication of circuits on the substrate.

As a solution to eliminate the Wallner pattern, a process step was introduced with a laser system, which takes place before the actual spalling process. This method is called laser-assisted spalling (LAS). Here, the horizontal plane of crack propagation through the working plane of the material is defined with short laser pulses and high numerical aperture of optics. Since the laser photon energy is chosen below the material band gap energy, the material is thus permeable to the laser radiation, so that a deep penetration into the material can be achieved. By translating the focusing optics along the optical axis, the plane of laser modification can be arbitrarily set and defined by the focal plane of the focusing optics, which can be adjusted with micrometer precision.

It is the object of the present invention to improve the known manufacturing method, in particular to make it more efficient or faster.

The aforementioned object is achieved by a method according to claim 1. The present invention thus preferably relates to a method for producing modifications in a solid body, wherein a tear guide region for guiding a crack for separating a solid portion, in particular a solid layer, from the solid is predetermined by the modifications. The method according to the invention preferably comprises at least the steps of: moving the solid body relative to a laser application device, successively generating a multiplicity of laser beams by means of the laser application device for generating in each case at least one modification, wherein the laser application device for the defined focusing of the laser beams, in particular continuously, as a function of at least one parameter, in particular set of a plurality of parameters.

Thus, a position-dependent laser power adjustment preferably takes place for adaptation to inhomogeneities of the samples or of the solid or of the substrate.

Depending on the manufacturing process z. B. Dotierinhomogenitäten in the solid state, which can be compensated advantageously by means of said solution. Example: Silizumcarbid (SiC) is produced in gas phase deposition by the injection of doping gas (N2), with the presence of a clearly visible doping spot. These inhomogeneities often require different laser parameters for the successful laser modification (sufficient damage especially without crack induction) than the average laser parameters for otherwise homogeneously assumed workpieces / samples. For most of the samples, the process parameters are robust (i.e., process windows are large enough) to successfully modify with average laser parameters for on average homogeneous samples. For larger local material property deviations, locally adjusted laser parameters must be used. Thus, in-line adjustments or adjustments with previous knowledge are conceivable.

This solution is advantageous because some materials (e.g., SiC) have local refractive index and other material property differences (eg, absorption, transmission, scattering) that can be compensated for or compensated for by position-dependent laser exposure adjustment. Preferably, one or more of the material properties serve: absorption, transmission, scattering, refractive index, etc. in each case as possible parameters. Depending on position, this means that there is a relative movement of the solid to be treated with respect to the laser application device.

It is thus conceivable here that the laser application device and / or the solid body are moved. The at least one parameter is preferably detected before the exposure of the solid with the laser beams in the context of an analysis step. The change in the parameter via the irradiation surface and / or via the applied volume of the solid is preferably stored as data in the form of characteristic profile data, and is particularly preferably used for driving the laser application device for position-dependent laser application of the solid. In addition, it is conceivable that a traversing device on which the solid body is arranged, in particular an XY table or a rotary table, is activated or operated as a function of the characteristic profile data. Alternatively, it is conceivable that the property profile data are generated and evaluated in real time, d. H. be used directly for driving the laser application device and / or the traversing device.

In-line adjustments are thus preferably based on changes that can be detected in real time (with sensor advance before machining position). Non-contact one-sided (ie reflective instead of transmissive) measuring methods are particularly suitable, such. B. spectral reflection. For adjustments with prior knowledge, a laser system is preferably required which reads in a map with correction factors K (x, y) as prior knowledge prior to processing and with the aid of which sets laser parameters locally (x, y). The specimens are preferably preferably provided on the traversing device, in particular the chuck / carrier, during the fixation, preferably with exact orientation, so that this prior knowledge can be registered with the chuck / carrier in the machine. To adjust the local energy density z. As a performance tracking, adapted writing patterns (other perforation density) or multiple crossings with different writing patterns.

According to a further preferred embodiment of the present invention, a first parameter is the average refractive index of the material of the solid or is the refractive index of the material of the solid in the region of the solid to be traversed to produce a defined modification of laser beams, or is the transmission of the Solid at defined points of the solid and preferred for a defined solid body depth. A second parameter, according to another preferred embodiment of the present invention, is the processing depth in the region of the solid to be traversed to produce a defined modification of laser beams. The first parameter is determined according to a further preferred embodiment of the present invention by means of a refractive index determination means, in particular by means of spectral reflection, and / or the second parameter is determined by means of a topography determination means, in particular by means of a confocal chromatic distance sensor. Data for the parameters, in particular for the first parameter and the second parameter, are provided in a data storage device according to a further preferred embodiment of the present invention and supplied to a control device at least prior to the generation of the modifications, wherein the Control device adjusts the laser application device in dependence on the respective location of the modification to be generated.

The present invention relates to a method for separating at least one solid-state layer from a solid, wherein the modifications provide a crack-guiding region for guiding a crack for separating a solid fraction, in particular a solid-state layer, from the solid. According to the invention, the method preferably comprises at least the following steps: moving the solid relative to a laser application device, successively generating laser beams by means of the laser application device to generate at least one modification, the laser application device for defined modification generation as a function of at least one parameter, in particular the transmission of the solid at defined locations and for a defined solid body depth is set, which are compensated by the setting of the laser application device inhomogeneities of the solid on the surface or in the area of the applied surface and / or in the volume of the solid or in the region of the applied volume of the solid. Separating the solid-state layer from the solid.

Data on the parameter or on several parameters is provided in a data storage device according to another preferred embodiment of the present invention and supplied to a controller at least prior to the generation of the modifications, the controller adjusting the laser applying device depending on the respective location of the modification to be generated.

According to a further preferred embodiment of the present invention, the laser beams for generating modifications have more energy in areas with low transmission than in areas with high transmission, wherein the laser application device preferably has an adjusting device, in particular an acousto-optical modulator, for adjusting the laser beam energy has.

According to a further preferred embodiment of the present invention, the solid state layer dissolves as a result of the modification generation along the crack guide region of the solid or the solid is thermally acted upon the generation of the modifications, in particular cooled, and dissolves due to the thermal loading of the solid layer of the solid along of the crack guide region or a polymer layer is arranged or generated on the solid body, wherein the polymer layer is preferably arranged or generated on a surface of the solid layer to be separated, wherein the polymer layer is thermally charged, in particular cooled, wherein the polymer layer on the thermal impingement of a change Strength undergoes, resulting in mechanical stress in the solid as a result of the change in strength of the polymer layer, the mechanical stresses a Rissausbreitun g along the crack guide portion for separating the solid layer from the solid cause.

The present invention preferably relates to a method for producing a detachment region in a solid body for detaching a solid fraction, in particular a solid layer, from the solid, wherein the solid fraction to be detached is preferably thinner than the solid reduced by the solid fraction. The process according to the invention preferably comprises at least the steps of: providing a solid to be processed, the solid consisting of a chemical compound; Providing a LASER light source; Subjecting the solid to laser radiation from the LASER light source, wherein the laser beams penetrate into the solid over a surface of the solid portion to be separated, and / or wherein the LASER radiation occupies a predetermined portion of the solid inside the solid to form one or more part removal portions defined tempered. Preferably, the temperature generated in the predetermined proportion of the solid by the laser beams is so high that the material forming the predetermined portion Undergoes modifications in the form of a predetermined material conversion. Particularly preferably, the modifications cause a pressure increase in the solid.

Additionally or alternatively, the present invention may relate to a method of separating at least one solid layer from a solid. This separation process preferably comprises at least the steps of: providing a solid to be processed, wherein the solid consists of a chemical compound; Providing a LASER light source; Applying to the solid body with LASER radiation of the LASER light source, wherein the laser beams penetrate into the solid via a surface of the solid portion to be separated, wherein the LASER radiation tempered defined a portion of the solid inside the solid to form a detachment region or more Teilablösebereiche. Preferably, the temperature generated in the predetermined proportion of the solid by the laser beams is so high that the material forming the predetermined portion undergoes modifications in the form of a predetermined material conversion. Particularly preferably, the modifications cause a pressure increase in the solid.

In this case, the solid state layer is preferably separated from the solid body as a result of the pressure increase along the crack guide region due to crack propagation.

According to a further preferred embodiment, the laser beams penetrate in the longitudinal direction of the solid or at an angle of up to 60 ° inclined to the longitudinal direction of the solid via a, in particular flat, surface, which is preferably part of the solid state layer in the solid. The tear guide region is preferably formed from a plurality of layers of modifications, wherein the layers are longitudinally spaced from each other or offset generated and / or at least several of the modifications have a longitudinal extension which is between 1 .mu.m and 50 .mu.m or between 5 .mu.m and 50 .mu.m , And / or the laser beams for generating the modifications are introduced into the solid state such that the numerical aperture is less than 0.8, in particular less than or equal to 0.5.

The present invention further relates to a method for producing at least one at least partially curved or curved solid layer. According to the invention, the method comprises at least the steps of: moving the solid relative to a laser application device, sequentially generating laser beams by means of the laser application device for generating at least one modification inside the solid, the modifications comprising a crack guide region for guiding a crack for separating a solid fraction, in particular a solid-state layer, from which solids are given, the modifications causing a rise in pressure in the solid, the solid-state layer being separated from the solid by crack propagation due to the pressure increase along the crack-leading region, with at least a portion of the modifications being separated from the solid as part of the solid-state layer is made, wherein the solid state layer is converted due to the modifications in a curved or curved shape, resulting from the crack guide area resulting additional surface portion of the solid state layer is thus at least partially convex shaped. The laser beams penetrate according to a further preferred embodiment of the present invention in the longitudinal direction of the solid or at an angle of up to 60 ° inclined to the longitudinal direction of the solid via a, in particular flat, surface, which is preferably part of the solid state layer in the solid and the The tear guide region is preferably formed from a plurality of layers of modifications, the layers being longitudinally spaced from one another or offset, and / or at least several of the modifications have a longitudinal extension ranging from 1 μm to 50 μm or between 5 μm and 50 μm μm, and / or the laser beams for generating the modifications are introduced into the solid such that the numerical aperture is less than 0.8, in particular less than or equal to 0.5.

Furthermore, the present invention relates to a method for separating at least one solid layer or solid state layer, in particular a solid state disk, from a solid or donor substrate. The method according to the invention preferably comprises at least the following steps: provision of a solid, generation of modifications inside the solid by means of LASER rays, the modifications providing a separation region or crack guidance region along which a separation of the solid layer from the solid takes place, ablation of material of the solid, in particular for producing a circumferential recess, wherein the removal area is exposed by the material removal.

Separating the solid-state layer from the solid. Preferably, the separation of the solid state layer of the solid body takes place in such a way that the solid body is weakened in the crack guide area by the modifications such that the solid state layer separates from the solid as a result of material removal or after the removal of material a number of modifications is produced such that the solid state in the Is weakened crack guide region such that the solid state layer separates from the solid or a voltage generating layer is generated or arranged on a inclined surface, inclined to the surrounding surface, in particular, surface of the solid and generated by thermal loading of the voltage generating layer mechanical stresses in the solid, wherein the mechanical stresses cause a crack to separate a solid layer which, starting from the surface of the solid exposed by the material removal, follows the modification NEN spreads or the solid after the generation of the modifications thermally acted upon, in particular cooled, and as a result of the thermal loading, the solid state layer separates from the solid body along the crack guide area.

The material removal takes place here preferably in the longitudinal direction of the solid.

The present invention further relates to a method for separating at least one solid layer or solid state layer, in particular a solid state disk, from a solid or donor substrate. The method according to the invention preferably comprises at least the following steps: provision of a solid, generation of modifications inside the solid by means of LASER rays, the modifications providing a release region or tear-propagation region along which a separation of the solid-state layer from the solid occurs, removal of Material of the solid, in particular for generating a circumferential recess, wherein the material removal takes place in the longitudinal direction of the solid, wherein the removal area is exposed by the material removal.

Separating the solid-state layer from the solid. Preferably, the separation of the solid state layer of the solid body takes place in such a way that the solid body is weakened in the crack guide area by the modifications such that the solid state layer separates from the solid as a result of material removal or after the removal of material a number of modifications is produced such that the solid state in the Fracture guide region is weakened such that the solid state layer separates from the solid or a voltage generation layer is generated or arranged on a inclined surface, inclined to the surrounding surface, in particular, surface of the solid and generated by thermal loading of the voltage generation layer mechanical stresses in the solid, wherein by the mechanical stresses a crack for separating a solid layer is formed, which, starting from the surface of the solid exposed by the material removal along the Modifikati onsun spreads or the solid after the generation of the modifications thermally acted upon, in particular cooled, and as a result of the thermal loading, the solid state layer separates from the solid body along the crack guide area.

The material is removed in accordance with a further preferred embodiment of the present invention, starting from an exposed, in particular flat, surface of the solid, in particular parallel to the peripheral surface of the solid, in the longitudinal direction of the solid and at least partially spaced from the peripheral surface of the solid.

The material is removed in accordance with a further preferred embodiment of the present invention in the form of an at least partially continuous trench, wherein the trench is preferably at least 30 microns or at least 100 microns or at least 500 microns or at least 1 mm from the peripheral surface spaced and preferably extends parallel thereto ,

After separation of the solid state layer, according to a further preferred embodiment of the present invention, at least the solid fraction of the solid formed between the trench and the peripheral surface is at least partially lapped, in particular by the thickness of the previously separated solid layer or solid layers, in particular ground , etched or polished.

The removal of material is effected according to a further preferred embodiment of the present invention by means of laser ablation or water jet cutting or etching.

Furthermore, the present invention relates to a method for generating a separation region in a solid body for detachment of a solid portion, in particular a solid layer, of the solid, wherein the solid portion to be detached is preferably thinner than the reduced by the solid content solid. The method according to the invention preferably comprises at least the steps of: providing a solid, setting a flow behavior of a gas, in particular air, located between the solid and the laser application device; to prevent accumulation of dust in the area of the laser radiation, and / or to produce modifications inside the solid by means of LASER radiation of a laser application device, wherein the modifications provide a separation region or tear guidance region along which a separation of the solid layer from the solid occurs.

Furthermore, the present invention also relates to a method for separating at least one solid layer or solid state layer, in particular a solid state disk, from a solid or donor substrate. The method according to the invention preferably comprises at least the steps of providing a solid, adjusting a flow behavior of a gas, in particular air, located between the solid and the laser application device, in particular in the region of the radiation path, to prevent accumulation of dust in the area of the laser radiation, generating modifications in the Inside of the solid body by means of laser radiation of a Laserbeaufschlagungseinrichtung, which is given by the modifications a separation region or crack guide region, along which a separation of the solid state layer of the solid takes place.

Separating the solid state layer of the solid, wherein in particular the solid body in the crack guide region is preferably weakened by the modifications such that the solid state layer as a result of the removal of material from the solid or after the material removal such a number of modifications is generated that the solid in the crack guide area so is weakened, that the solid state layer separates from the solid or a voltage generating layer is generated or arranged on a inclined surface, inclined to the surrounding surface, in particular, surface of the solid and are generated by thermal loading of the voltage generating layer mechanical stresses in the solid, wherein by the mechanical stresses a crack for separating a solid layer is formed, which is based on the exposed by the removal of material surface of the solid along the modifications au sbreitet or the solid after the generation of the modifications thermally acted upon, in particular cooled, and as a result of the thermal loading, the solid state layer separates from the solid body along the crack guide region.

The adjustment of the flow behavior is carried out according to a further preferred embodiment of the present invention by supplying a fluid, in particular ionized gas, in the region of the beam path between a lens and the solid or the adjustment of the flow behavior by generating a negative pressure, in particular a vacuum in the range of the beam path between a lens and the solid.

The present invention can likewise relate to a method for producing a detachment region in a solid for detaching a solid fraction, in particular a solid layer, from the solid, wherein the solid fraction to be detached is preferably thinner than the solid reduced by the solid fraction. Preferably, this method preferably comprises at least the steps of providing a solid, the solid having at least one coating whose refractive index differs from the refractive index of the surface of the solid on which the coating is disposed, or wherein a coating is formed on the solid of which the refractive index differs from the refractive index of the surface of the solid on which the coating is arranged, producing modifications inside the solid by means of LASER rays of a laser application device, the modifications providing a release region or tear guide region along the one Separation of the solid state layer of the solid takes place.

The present invention further relates to a method for separating at least one solid layer or solid state layer, in particular a solid state disk, from a solid or donor substrate, comprising at least the steps: providing a solid, wherein the solid has at least one coating whose refractive index to the refractive index of the surface of the solid on which the coating is arranged, is different, or wherein on the solid body, a coating is produced whose refractive index differs from the refractive index of the surface of the solid on which the coating is arranged, generating modifications in the interior of the solid by means of LASER rays of a laser application device, wherein the modifications provide a crack guidance region along which a separation of the solid layer from the solid occurs.

Separating the solid layer of the solid, wherein the solid body in the crack guide region is preferably weakened by the modifications such that the solid layer peels off as a result of material removal from the solid or after the removal of material such a number of modifications is generated that the solid weakened in the crack guide area so is that the solid state layer separates from the solid or a voltage generation layer is generated or arranged on a surface inclined to the surrounding surface, in particular flat, surface of the solid and are generated by thermal loading of the voltage generating layer mechanical stresses in the solid, wherein by the mechanical Tensions a crack for separating a solid layer arises, which propagates from the surface of the solid exposed by the material removal along the modifications or the solid body after the generation of the modifications is thermally acted upon, in particular cooled, and as a result of the thermal loading, the solid state layer separates from the solid body along the crack guide region.

The coating is produced or produced according to a further preferred embodiment of the present invention by means of spin coating, the coating comprising nanoparticles, in particular of at least one material selected from the list consisting at least of silicon, silicon carbide, titanium oxide, glass or Al 2 O 3.

Several coatings are according to a further preferred embodiment of the The present invention may be stacked on top of one another or produced one above the other with their indices of refraction being different, preferably, a first coating disposed on or generated on the solid has a greater refractive index than an additive coating produced on the first coating.

The coatings are thus preferably selected and produced or arranged such that the refractive index of the respective layer preferably decreases or decreases with the distance between the respective layer and the solid. Thus, in a layering: 1. solid, 2. first coating, 3. second coating, 4. third coating, the refractive index of the solid is preferably greater than the refractive index of the first coating and the refractive index of the first coating is preferably greater than the refractive index of the second Coating and the refractive index of the second coating is preferably greater than the refractive index of the third coating. The steps between the refractive indices may be continuous or discontinuous. Furthermore, the different coatings may have different thicknesses. However, it is conceivable that two or three or more of the coatings have the same thickness. Preferably, a coating in each case has a thickness in the range between 50-400 nm. This means that z. B. the first coating may have a thickness (or average thickness) of 100 nm. The thicknesses of the second coating and the third coating may thus substantially coincide or completely coincide, at least one of the coatings, and preferably both, having a thickness deviating therefrom. Thus, the second coating z. B. have a thickness (or average thickness) of 150 nm. Furthermore, the third coating may be thicker or thinner than the first coating and / or as the second coating, such as. B. have a thickness (or average thickness) of 75 nm, 110 nm or 300 nm.

The present invention further relates to a method for producing a separation region in a solid body for detaching a solid fraction, in particular a solid layer, from the solid, wherein the solid fraction to be detached is preferably thinner than the solid reduced by the solid fraction. The method according to the invention preferably comprises at least the following steps: provision of a solid, generation of modifications inside the solid by means of LASER radiation of a laser application device, wherein the modifications provide a crack guidance region along which a separation of the solid layer from the solid occurs, the laser radiation irradiated at Brewster angle or with a deviation in the range of -5 ° to + 5 ° from the Brewster angle on the solid. Furthermore, the present invention relates to a method for separating at least one solid layer or solid state layer, in particular a solid state disk, from a solid or donor substrate. In this case, the method according to the invention comprises at least the steps of providing a solid, generating modifications inside the solid by means of LASER radiation of a laser application device, wherein the modifications provide a crack guidance region along which a separation of the solid layer from the solid occurs, the laser radiation at Brewster angle or with a deviation in the range of -5 ° to + 5 ° from the Brewster angle on the solid radiates, separating the solid state layer of the solid. Preferably, the separation of the solid layer of the solid body along the crack guide region, wherein the solid body is weakened in the crack guide area by the modifications such that the solid state layer due to the removal of material separates from the solid or before or after the material removal such a number of modifications is generated the solid body in the crack-guiding region is weakened such that the solid-state layer is detached from the solid body or a voltage-generating layer is produced or arranged on a surface of the solid which is inclined relative to the circumferential surface, and thermal stresses on the voltage-generating layer cause mechanical stresses in the solid body produced by the mechanical stresses, a crack for separating a solid layer is formed, which is based on the exposed by the material removal surface of the F estkörpers propagates along the modifications or the solid body after the generation of the modifications thermally acted upon, in particular cooled, and as a result of the thermal loading, the solid state layer separates from the solid body along the crack guide area.

The laser radiation here and preferably in all embodiments described herein is preferably polarized radiation.

A compensation device, in particular an optical element, such as a diffractive optical element or a continuous wedge, for compensating a spherical aberration resulting from the Brewster angle radiation is provided in the laser application device in accordance with a further preferred embodiment of the present invention.

The present invention further relates to a method of separating at least one solid layer from a solid, wherein by the modifications a crack guide region for guiding a crack for separating a solid portion, in particular a solid layer, is predetermined by the solid. The method preferably comprises at least one or more or all of the following steps: moving the solid relative to a laser application device, successively generating laser beams by means of the laser application device to generate at least one modification, separating the solid state layer from the solid.

According to a further preferred embodiment of the present invention, the solid body in the crack guide region is weakened by the modifications such that the solid layer is detached from the solid as a result of the removal of material or after the material removal a number of modifications is produced such that the solid is weakened in the crack guide region in that the solid-state layer is detached from the solid body or a voltage-generating layer is produced or arranged on a surface of the solid which is inclined relative to the circumferential surface and mechanical stress is generated in the solid by thermally loading the voltage-generating layer, the mechanical stresses a crack is formed for severing a solid layer emerging from the surface of the solid exposed by the material removal along the modifications Itet or the solid after the generation of the modifications thermally acted upon, in particular cooled, and as a result of the thermal loading, the solid state layer separates from the solid body along the crack guide region.

In accordance with a further preferred embodiment of the present invention, the laser application device is set for defined modification generation as a function of at least one parameter, in particular the transmission of the solid, at defined locations and for a defined solid body depth and / or the modifications bring about an increase in pressure in the solid body, wherein the solid state layer As a result of the increase in pressure along the crack guide region, crack propagation separates the solid from the solid, wherein preferably at least a portion of the modifications as a constituent of the solid layer is separated from the solid, and the solid layer is preferably converted into a curved or domed form due to the modifications resulting from the crack guide area further surface portion of the solid state layer thus at least partially and preferably at least in profile preferably convex gef is and / or the solid has at least one coating whose refractive index differs from the refractive index of the surface of the solid on which the coating is arranged, or wherein on the solid a coating is produced whose refractive index to the refractive index of the surface of Solid body, on which the coating is arranged, is different, and / or wherein the laser radiation irradiates in the Brewster angle or with a deviation in the range of -5 ° to + 5 ° from the Brewster angle on the solid, in addition or alternatively in this case conceivable that the method comprises one or more of the following steps: removal of material of the solid, in particular for generating a circumferential recess, wherein the removal of material takes place in the longitudinal direction of the solid, which is exposed by the material removal of the crack guide region, and / or setting a Flow behavior of a between Festkö and the laser application device, in particular in the region of the course of the radiation, of the gas present, in particular air, in order to prevent accumulation of dust in the region of the laser radiation.

The use of the words "substantially" preferably defines a deviation in the range of 1% -30%, in particular of 1% -20%, in particular of 1% -10, in all cases in which these words are used in the context of the present invention %, in particular from 1% -5%, in particular from 1% -2%, of the definition that would be given without the use of these words. Individual or all representations of the figures described below are preferably to be regarded as construction drawings, d. H. the dimensions, proportions, functional relationships and / or arrangements resulting from the figure or figures preferably correspond exactly or preferably substantially to those of the device according to the invention or of the product according to the invention. Further advantages, objects and features of the present invention will be explained with reference to the following description of appended drawings, in which exemplary devices according to the invention are shown. Elements of the devices and methods according to the invention, which in the figures at least substantially coincide with regard to their function, may hereby be identified by the same reference symbols, these components or elements not having to be numbered or explained in all figures. The invention will be described purely by way of example with reference to the accompanying drawings.

This shows by way of example:

1 schematically the compensation of material properties by adjusting the Laser exposure depending on local property differences of the material;

2a schematically the generation of a modification sufficient to cause a crack;

2 B schematically the generation of a modification compared to the modification 2a has a much greater extent in the longitudinal direction of the solid and after the cleavage of the solid state layer causes the solid state layer bulges or bends;

3 schematically the creation of a trench in a solid body, wherein the trench is preferably spaced from the outer circumferential surface of the solid;

4a schematically an arrangement in which particles such. As dust, accumulate in the course of the laser radiation, in particular at the intersection of the reflected rays;

4b schematically an arrangement in which a rinse, in particular by means of gas, such. As ionized gas, is provided which removes particles from the intersection of the reflected rays;

5 schematically an arrangement according to which one or more coating (s) are arranged on the solid body, wherein the coating (s) preferably has or have at least one other optical property than the solid body;

6a schematically the irradiation of laser beams in the Brewster angle;

6b Gradients to illustrate the relationship between angle of incidence and reflection;

7 - 18 examples for the calculation of the optimal angle of incidence for a 1 / e2 Gaussian profile and various numerical apertures taking into account the refractive index dependence of the surface reflection;

19a schematically the course of the cold-split process;

19b schematically the course of the laser-assisted spalling process;

19c a photograph of a surface of a solid state layer exposed according to the method 19a;

19d a photograph of a surface of a solid state layer exposed according to the method 19b;

20a -F SEM images of surfaces;

21a a micrograph of a surface after spalling;

21b Raman spectra of three different sites in 6H silicon carbide;

22 an example of a laser beam profile; and

23a schematically an example of the result of a first number of modifications and / or modification layers resulting bending of the solid state layer produced; and

23b schematically another example of the result of a second number of modifications and / or modification layers resulting bending of the solid state layer produced, the second number is greater than the first number.

In 1 FIG. 3 is a schematic diagram of a structure for carrying out a method for separating at least one solid-state layer 14 from a solid 1 shown. Through the modifications 2 a crack guide area 4 to guide a crack to separate a solid portion 14 , in particular a solid layer, of the solid 1 is given. By doing that, the laser beams 10 . 11 in different places of the solid 1 are shown, it can be seen that the solid 1 relative to a laser applying device 8th is moved. The laser beams shown 10 and 11 thus represent situations at different times. Basically, the generation of laser beams 10 by means of the laser application device 8th for generating in each case at least one modification 2 , wherein the laser application device 8th for defined modification generation as a function of at least one parameter, namely the transmission of the solid 1 is set at defined locations and for a defined solid body depth. In the illustration according to 1 represent the laser beams 10 . 11 thus laser beams with different properties or with at least one different property. The laser beam 10 to laser beam 11 changed property contributes to the changed material properties in the respective applied area of the solid 1 Bill. The laser beam 11 acted in the case shown z. B. a region of the solid 1 , which has a modified transmission, the z. B. may result from a Dotierfleck.

Preferably, after the generation of the modifications 2 separating the Solid layer 14 from the solid 1 as shown by 19b ,

2a shows a situation where modifications 2 with a first extension in the longitudinal direction L of the solid 1 be generated. The longitudinal direction L in this case preferably extends orthogonally or substantially orthogonally to the irradiation surface 17 of the solid 1 , wherein the Einstrahloberfläche 17 of the solid 1 after separating the solid state layer 14 Part of the solid state layer 14 is. This is particularly preferred for all embodiments described in this document. The according to 2a generated modifications 2 are for guiding a crack to separate the solid state layer 14 sufficient.

2 B shows an embodiment according to which the modifications produced 2 one opposite 2a have greater extent in the longitudinal direction L. Additionally or alternatively, several, in particular two or three or more than two or three, layers of modifications 2 be generated at least in sections.

This is advantageous since the stress that the laser layer generates in the unmodified material can be increased by a greater than necessary expansion of the laser layer in the beam direction (depth or solid-state length). Thus, more material may preferably undergo phase transformation or be amorphized or otherwise modified - as needed for the polymer split (cf. 19b ). This increased stress serves to convey the spontaneous split of the material (without polymer). The laser parameters or laser beam parameters or parameters with which the laser application device is configured - for the spontaneous split and the polymer process - can differ considerably, for B. in required numerical aperture and / or pulse length and / or pulse energy. A larger extent of the laser layer leads to a higher pressure in the solid, which increases the spontaneous split probability. Furthermore, this embodiment is advantageous because a solid state layer 14 as a curved or curved solid layer 14 can be generated. Thus, this method can preferably also for producing at least one at least partially curved or curved solid state layer 14 use. To produce a curved or bent solid-state layer (or curved or curved wafer), the method preferably comprises at least the following steps: moving the solid 1 relative to a laser applying device 8th , successively generating laser beams 10 by means of the laser application device 8th for generating in each case at least one modification 2 inside the solid, taking through the modifications 2 a crack guide area 4 to guide a crack to separate a solid portion 6 , in particular a solid layer, of the solid 1 is given, the modifications cause an increase in pressure in the solid, wherein the solid state layer 14 due to the pressure increase along the crack guide area 4 by a crack propagation from the solid 1 is separated, with at least a portion of the modifications 2 as part of the solid state layer 14 from the solid 1 is separated, wherein the solid state layer 14 due to the modifications 2 is converted into a curved or curved shape, which is from the crack guide area 4 resulting additional surface portion 16 the solid state layer is thus at least partially convex.

3 shows an arrangement, according to the preferred after the generation of a crack guide area 4 in the solid state 1 at least in sections and preferably around a trench 26 starting from the Einstrahloberfläche 17 in the longitudinal direction L of the solid 1 is produced. After the creation of the trench 26 can the solid state layer 14 by creating further modifications 2 by means of laser beams 10 , which preferably also on the Einstrahloberfläche 17 are introduced, are separated from the solid. Alternatively, a voltage generation layer is preferable 18 at least on the ditch 26 enclosed or surrounded or limited area, in particular on the surface of the later solid state layer 14 , arranged or generated.

The voltage-generating layer preferably consists of a polymer material, in particular PDMS, and is preferably applied in a further step at least in sections and particularly preferably completely thermally, in particular cooled, in particular cooled below its glass transition temperature. This is preferably true for all embodiments described herein in which a voltage generation layer is used.

As a result of stress generation, a crack separates the solid state layer 14 from the remaining solid 1 from.

Preferably, in a further step, a surface treatment of the solid body 1 , It is preferred to be between the ditch 26 and the peripheral surface resulting frame 28 and / or by the separation of the solid state layer 14 exposed surface of the solid 1 smoothed, in particular ground, lapped, polished or etched. The frame is preferred 28 and the exposed surface in such a way, in particular machined, treats that their surfaces lie in the same plane.

It is thus according to the invention a method for separating at least one solid state layer or solid state layer, in particular a solid state disk, 14 from a solid or donor substrate 1 provided that preferably comprises at least the following steps: providing a solid 1 , Creating modifications 2 inside the solid 1 using LASER rays 10 , where by the modifications 2 a release region or crack guide region is predetermined, along which a separation of the solid state layer 14 from the solid 1 takes place, removal of material of the solid 1 , in particular for producing a circumferential recess 12 wherein the removal of material in the longitudinal direction of the solid takes place, wherein the removal of material is exposed by the removal of material, and separating the solid layer of the solid.

This is advantageous because laser processing up to the edge is problematic and thus the solid state layer produced 14 also has very homogeneous properties in its edge region. The basic concept presented here thus preferably comprises a laser ablation / grinding / removal of material from above for producing a notch or a trench, whereby the laser layer produced beforehand is opened or uncovered. Subsequently, a lifting out of the solid state layer 14 or the target wafer with the voltage generation layer 18 , The surviving edge or frame 28 can then be ground away again during a further surface treatment. Thus, by ablation from above, in particular by water jet cutting or laser ablation, the laser layer exposed and edge effects in the polymer split can be avoided.

4a shows an arrangement in which particles such. B. dust, at the with the reference numeral 30 characterized crossing point of the reflected radiation, accumulate and thus adversely affect the modification generation.

4b shows an arrangement in which a purging device 32 or rinsing is provided. It is thus preferably a fluid, in particular a gas and preferably an ionized gas, the intersection point 30 fed to those in the crossroads 30 rinse away accumulating particles by means of the fluid flow.

Thus, a method for separating at least one solid state layer or solid state layer, in particular a solid state disk, 14 from a solid or donor substrate 2 provided that preferably comprises at least the following steps: providing a solid 1 , Setting a flow behavior of a between the solid and the laser application device 8th , in particular in the region of the course of radiation, located gas, in particular air, to prevent accumulation of dust in the region of the laser radiation, generating modifications 2 inside the solid 1 using LASER rays 10 a laser applying device 8th , where by the modifications 2 a release region or crack guide region is predetermined, along which a separation of the solid state layer 14 from the solid 1 takes place and separating the solid state layer of the solid. This solution is advantageous because high laser intensities charge static dust and this dust can be flushed out of the area between the lens and the workpiece by the flushing, in particular with ionized gas. The gas flush thus drives the dust out of the space between the lens 9 the laser application device 8th and the workpiece or solid 1 , Additionally or alternatively, the fluid flow, in particular the gas flow, can be guided through the objective for producing a cooling effect against absorbed power. Thus, the objective is preferably designed for conducting a fluid, in particular the flushing fluid.

Furthermore or in addition, a compensation of spherical aberrations on the lens can take place. This alters the focus on the surface (inclusion of the material traversed with different index of refraction), whereby the focus in air deteriorates and thus has a lower intensity, which in turn leads to a lower particle suction effect or vacuum cleaner effect. Additionally or alternatively, reduced reflection at the surface may be effected. This can be z. B. by the application of certain layers or coatings, in particular by spin coating, and / or caused by Brewster irradiation with polarized light.

5 shows a schematic arrangement, according to which the solid state 1 with at least one coating 34 is provided. The coating 34 may be one or more layers. The coating preferably has a difference in refractive index from the refractive index of the material of the solid 1 in particular, the refractive index of the material of the solid is 1 preferably higher than that of the coating 34 , It is also conceivable that the coating 34 is constructed of several layers, wherein preferably at least two of the plurality of layers have a refractive index difference. Preference is given to the refractive index of the respective layer closest to the solid 1 is arranged larger than the refractive index of a layer to the solid 1 is further spaced.

This schematic structure thus enables according to the invention a method for separating at least one solid state layer or solid state layer, in particular a solid state disk, 14 from a solid or donor substrate 1 provide. In this case, this process preferably comprises at least the following steps: Provision of a solid 1 , where the solid 1 at least one coating 34 whose refractive index is the refractive index of the surface of the solid 1 on which the coating 34 is arranged, is different, or being on the solid 1 a coating 34 is generated whose refractive index to the refractive index of the surface of the solid 1 on which the coating 34 is arranged, is different, generating modifications 2 inside the solid 1 using LASER rays 10 a laser applying device 8th , where by the modifications 2 a crack guide area 4 (see analog 1 ), along which is a separation of the solid-state layer 14 from the solid 1 he follows.

The generation of the coating may, for. B. by means of spin coating. So brings z. As a solvent, mixed with nanoparticles of materials with high refractive index one or more thin (sub-wavelength) layers with a slightly higher refractive index on the solid 1 or the workpiece 1 This creates an interface with reduced refractive index difference. Less reflection on the surface. Less contamination, more material in the material for more efficient material processing. Spin coating is advantageous because it is fast and cheap cheap and fast, possible nanoparticles are in addition to others or in addition to other z. Silicon (n = 2.6), titanium oxide (n = 1.8), glass (n = 1.5), Al2O3 (n = 1.72). In the case of several layers, with gradually increasing refractive index for even more efficient refractive index matching and antireflection effect, a multi-layer process is conceivable. Purely by way of example, it would then be possible to produce a layer arrangement which consists of the following layers or layers: 1st layer: Si, 2nd layer: SiC, 3rd layer: TiO2, each layer preferably 50-400 nm thick. This method is also advantageous because by means of spin-coating of such layers, even the smallest roughnesses on the material surface can be compensated (better material coupling, less scattering at the interface, better wavefront overlap in the focus in the depth and thus a lower laser power is needed This leads to a more efficient processing, since a higher multiphoton transition probability results, the spin-coating layer or the generation of a coating 34 can be used as part of the surface conditioning and reprocessing step on the ingot or solid 1 after the split or separation of the solid state layer 14 be applied. Thus, first of all, a grinding / lapping / etching or polishing step can be carried out and, subsequently or in combination with one of the preceding steps, the spin-coating step or the coating step which comprises the thin layer or coating 34 applies.

6 schematically shows an arrangement for coupling laser beams 10 In this arrangement, the reflection is reduced. The laser beams are preferred 10 coupled in at Brewster angle. The Brewster angle is an angle of incidence for light of a given polarization (E-vector points into the material, not along the surface), where no reflection occurs. The prerequisites for this are that the light is irradiated at an angle dependent on the refractive index difference between air and material. Furthermore, the light must be polarized (commonly used in laser light, requires single-mode lasers and no photonic crystal fibers). The Brewster angle coupling thus serves to minimize back reflections. When irradiated at Brewster's angle, the 30% surface reflectance can be used almost completely for material processing in the depth of the material.

Irradiation below the Brewster angle is complicated, since the different beam components travel different distances in the high-refractive medium. The focus must therefore be adjusted by higher energy and / or by beam shaping. The beam shaping is preferably z. B. over one or more diffractive optical element (s) (DOE), which compensates for this difference depending on the laser beam profile. The Brewster angle is relatively large, which makes demands on the optics and their dimensions and working distance with high numerical aperture. Nevertheless, this solution is advantageous because reduced reflections on the surface also contribute to reduced surface damage, since the light intensity better couples into the material. For the purposes of this invention, laser beams 10 also in all other disclosed in this document embodiments are irradiated at Brewster angle or substantially at Brewster angle. For Brewster angle coupling is hereby on the Optical Properties of Spin-Coated TiO 2 Antireflection Films on Textured Single-Crystalline Silicon Substrates (Hindawi Publishing Corporation International Journal of Photoenergy, Volume 2015, Article ID 147836, 8 pages, http://dx.doi.org/10.1155/ 2015/147836) directed. This document is incorporated herein by reference in its entirety. The above-mentioned and incorporated document discloses, in particular, calculations for the optimal angle of incidence for different materials and thus refractive indices. The energy of the laser or laser application device 8th is not so much depending on the material, but rather of the possible transmission at a certain angle customized. So if the optimal transmission z. B. 93%, these losses must be compared to experiments with vertical radiation and losses of z. B. then 17% are taken into account and the laser power can be adjusted accordingly.

An example: 83% transmission perpendicular to 93% below angle, means that to obtain the same energy at depth, only 89% of the laser power used for vertical irradiation is needed (0.83 / 0.93 = 0.89). For the purposes of the invention, the part of the oblique irradiation thus preferably serves to lose less light by surface reflection and to bring more into the depth. A possible downstream problem that can arise in certain constellations is that the depth of focus can be "skewed" and thus the intensities achieved - the key size for multiphoton processing - are again lower, possibly even lower than vertical Irradiation, where all beam components pass through the same optical path in the material. This can then be done preferably by a diffractive optical element or by a plurality of diffractive elements or a continuous wedge or more continuous wedges - and / or other optical elements - in the beam path, these additional ways and / or the influence on the individual beams - especially different compensate for spherical aberrations across the beam profile. These DOEs can be calculated numerically with suitable software solutions (eg Virtuallab from Lighttrans, Jena) and then manufactured or made available.

Thus, the present invention provides a method for separating at least one solid layer or solid state layer, in particular a solid state disk, 14 from a solid or donor substrate 1 ready. The method according to the invention preferably comprises at least the steps of providing a solid 1 , Creating modifications 2 inside the solid 1 using LASER rays 10 a laser applying device 8th , where by the modifications 10 a crack guide region is given, along which a separation of the solid layer 14 from the solid 1 takes place, wherein the laser radiation in the Brewster angle or with a deviation in the range of -10 ° to + 10 ° from the Brewster angle on the solid 1 irradiates. Furthermore, the method preferably comprises the step of separating the solid state layer 14 from the solid 1 ,

It was thus recognized in the context of the present invention that a high refractive index difference between air / material means power losses up to 30% in the case of perpendicular irradiation. For 100 W lasers, 30 W are not available for material processing or have other effects. So z. B. further recognized that dirt on the optics, as in so-called. "Opt. Tweezers ", can arise. The smallest dust particles, both in air and in liquids at high laser intensities, always move to the focus of the laser beam (highest intensity) - reflected power at the surface has focus in the air or in the vicinity of the optics, the dust is driven / pulled to the optics. Furthermore, it was recognized that at 100 W laser power and 97% transmission at the same time, significant heat (3 W) could enter the lens, which has to be dissipated / compensated in order to avoid thermal damage / changes to the process. It was also recognized that high performance brings with it the danger of surface damage. Because the absorption of the material can be increased due to surface conditions on the surface, smallest dust particles can therefore in the laser beam 10 first burn and then form absorption nuclei, which can lead to further damage through absorption. It has also been recognized that high powers with diffractive optical elements (DOEs) are split across multiple focal plane focal planes. DOEs show interference already in front of the focal plane, it has been recognized that surface interference, in front of the focal plane, can produce local intensity maxima that can damage the surface and result in reduced laser transmissivity for deep-depth processing. Furthermore, it was recognized that some materials (Ex: SiC) have local refractive index and other material property differences (eg absorption, transmission, scattering), e.g. B. by the material doping (frequent occurrence: Dotierfleck) have. It has also been found that, depending on the surface roughness of the material at the laser interface, the wavefront of the laser can be significantly affected in the depth of the material, so that the focus has reduced intensity (lower multiphoton transition probability), which again results in higher intensities with the above problems would.

Individual, several or all of these problems can be addressed by individual or combinations of the methods disclosed herein. Thus, the present invention may be preferably understood as a method of separating at least one solid layer from a solid. With this procedure by the modifications 2 preferably a crack guide area 4 to guide a crack to separate a solid portion 6 , in particular a solid layer, of the solid 1 is given. The inventive method preferably comprises at least the steps: moving the solid 1 relative to a laser applying device 8th , successively generating laser beams 10 by means of the laser application device 8th for generating each at least one modification 2 Separating the solid-state layer from the solid.

Thus, according to the invention, a spalling process is described that scales favorably in particular for large-area semiconductor substrates of up to 300 mm or more than 300 mm in diameter. In order to eliminate Wallner line patterns, a laser conditioning process, especially with high numerical aperture, is used at photon energies, preferably below the material bandgap energy. This process leads to multiphoton interactions in the material and, after the spalling process, gives a surface roughness of preferably Ra <1 μm.

Preferably, one or more of the abovementioned solutions according to the invention can be combined with one another, since an even better solid-state layer production or solid-state layer separation can thereby be effected. Thus, according to the method according to the invention, the laser application device 8th for the defined modification generation as a function of at least one parameter namely the transmission of the solid at defined locations and set for a defined solid body depth and / or the modifications cause a pressure increase in the solid, wherein the solid state layer is separated due to the pressure increase along the crack guide area by a crack propagation from the solid , wherein preferably at least a portion of the modifications as a constituent of the solid layer is separated from the solid and wherein the solid layer is preferably converted due to the modifications in a curved or curved shape, wherein the resulting from the crack guide area further surface portion of the solid layer thus formed at least partially convex is and / or the solid has at least one coating whose refractive index to the refractive index of the surface of the solid to which the coating a is arranged, is different, or on the solid, a coating is produced whose refractive index to the refractive index of the surface of the solid on which the coating is arranged, and / or the laser radiation radiate at Brewster angle or with a deviation in Range from -5 ° to + 5 °, in particular with a deviation in the range of -4 ° to + 4 ° or with a deviation in the range of -3 ° to + 3 ° or with a deviation in the range of -2 ° to + 2 ° or with a deviation in the range of -1 ° to + 1 ° from the Brewster angle on the solid, and / or the method additionally or alternatively comprises one or more of the steps: removal of material of the solid 1 , in particular for producing a circumferential recess 12 wherein the material removal takes place in the longitudinal direction of the solid body, wherein the material removal of the crack guide area is exposed, or adjusting a flow behavior of a between the solid body and the laser application device 8th , in particular in the region of the course of radiation, located gas, in particular air, to prevent dust accumulation in the laser radiation.

The 7 - 18 show examples for the calculation of the optimal angle of incidence for a 1 / e2 Gaussian profile and different numerical apertures taking into account the refractive index dependence of the surface reflection.

The 7 - 10 show the progress of silicon carbide (n = 2.7)
Objective: To maximize the laser power coupled into the sample, ideally by utilizing the Brewster angle for minimal surface reflection in p-polarized light.
Result: For a NA = 0.8, Brewster coupling is not worthwhile (beam cone is already coupled under Brewster externally), smaller NA can benefit from this, in particular NA = 0.2, higher NA have an ideal angle between them.

7 shows in the figure above: relative coupled power over beam angle for gauss profile and in the figure below: Reflection coefficient for p- (red) and s- (blue) polarized light and angle Gauss profile for imaged NA = 0.2 (green), more optimal Beam angle here 63.8 °.

8th shows in the upper figure: relative coupled power over beam angle for gauss profile and in the lower figure: reflection coefficient for p- (red) and s- (blue) polarized light and angle Gauss profile for imaged NA = 0.4 (green), more optimal Beam angle here 52.5 °.

9 shows in the upper figure: relative coupled power over beam angle for gauss profile and in the figure below: Reflection coefficient for p- (red) and s- (blue) polarized light and angle Gauss profile for imaged NA = 0.6 (green), more optimal Beam angle here 35.6 °.

10 shows in the upper figure: relative coupled power over beam angle for Gaussian profile and in the figure below: Reflection coefficient for p- (red) and s- (blue) polarized light and angle Gauss profile for imaged NA = 0.8 (green), more optimal Angle of incidence here 0 °.

The 11 - 14 show the gradients when using silicon (n = 3.6).

The aim here is to maximize the laser power coupled into the sample, ideally by exploiting the Brewster's Angles for minimal surface reflection in p-polarized light. The result: For a NA = 0.8, Brewster coupling is not worthwhile (beam cone is already coupled almost under Brewster), smaller NA can benefit from this, in particular NA = 0.2, higher NA have an ideal angle between them.

11 shows in the figure above: relative coupled power over angle of incidence for gaussian profile for silicon and in the figure below: Reflection coefficient for p- (red) and s- (blue) polarized light and angle Gauss profile for mapped NA = 0.2 (green) , optimum angle of incidence here 67.9 °.

12 shows in the figure above: relative coupled power over angle of incidence for Gaussian profile for silicon and in the figure below: Reflection coefficient for p- (red) and s- (blue) polarized light and angle Gauss profile for mapped NA = 0.4 (green) , optimal angle of incidence here 57.4 °.

13 shows in the figure above: relative coupled power over angle of incidence for gaussian profile for silicon and in the figure below: reflection coefficient for p- (red) and s- (blue) polarized light and angle Gauss profile for mapped NA = 0.6 (green) , optimal angle of incidence here 43.6 °.

14 shows in the figure above: relative coupled power over angle of incidence for Gaussian profile for silicon and in the lower figure: reflection coefficient for p- (red) and s- (blue) polarized light and angle Gauss profile for mapped NA = 0.8 (green) , optimum angle of incidence here 0 °.

The 15 - 18 show the processes when using sapphire / ALO (n = 1.72)
The objective here is to maximize the laser power coupled into the sample, ideally by exploiting the Brewster angle for minimal surface reflection in p-polarized light. The result: For a NA = 0.8, Brewster coupling is not worthwhile (beam cone is almost already coupled under Brewster), smaller NA can benefit from this, in particular NA = 0.2, higher NA have an intermediate ideal angle, where NA = 0.6 almost no angle needed for irradiation.

15 shows in the figure above: relative coupled power over beam angle for Gauss profile for ALO and in the figure below: reflection coefficient for p- (red) and s- (blue) polarized light and angle Gauss profile for imaged NA = 0.2 (green) , optimum angle of incidence here 54.9 °.

16 shows in the figure above: relative coupled power over beam angle for Gauss profile for ALO and in the figure below: reflection coefficient for p- (red) and s- (blue) polarized light and angle Gauss profile for mapped NA = 0.4 (green) , optimum angle of incidence here 41.2 °.

17 shows in the figure above: relative coupled power over beam angle for Gauss profile for ALO and in the figure below: reflection coefficient for p- (red) and s- (blue) polarized light and angle Gauss profile for imaged NA = 0.6 (green) , optimum angle of incidence here 14.5 °.

18 shows in the figure above: relative coupled power over beam angle for Gauss profile for ALO and in the lower figure: reflection coefficient for p- (red) and s- (blue) polarized light and angle Gauss profile for imaged NA = 0.8 (green) , optimum angle of incidence here 0 °.

19a outlined a standard procedure for the laser-free spalling of large-area substrates. The wafer samples,
which are usually used have sharp edges to avoid complications from rounded edges. Rounded edges are used in conventional wafers to prevent the occurrence of cracks at the wafer edges that can run inward and then interfere with the substrate and manufacturing processes thereon.

The process is preferably as follows: after a standard cleaning process, the wafers are coated with a primer layer to improve surface adhesion and a sacrificial layer to ultimately improve polymer-wafer separation. The wafer is then coated with a different thickness PDMS (polydimethylsiloxane) polymer film and a PDMS adhesive - with platinum polymerization catalyst.

The samples are then pre-cooled to a temperature just above the polymer glass transition temperature before being immersed in liquid nitrogen. Depending on the size of the sample, the sample will have reached the temperature of liquid nitrogen up to 20 seconds later. The system is in thermal equilibrium at this time. The semiconductor layers then separate in a spontaneously occurring spalling event. The spalling process is induced by the polymer glass transition, and as a result, Young's modulus in the polymer greatly increases. The additional difference in thermal expansion coefficients (CTE) between semiconductor and polymer then induces sufficient stress to horizontally separate the crystal. It is important that the process requires a relative contraction of the polymer with respect to the semiconductor. Another The process step involves immersing the semiconductor parts with attached PDMS films in a separating bath, which finally dissolves the sacrificial layer, thereby enabling recycling of the polymer as well as providing the semiconductor wafers for further processing steps.

19a Thus, Figure 1 shows a map of conventional spalling of substrates with an ensemble of preferably two stress layers, ie polymer films. The films are attached to both sides of the substrate, followed by a rapid cooling step to induce thermal cycling followed by cracking and separation of the substrate.

The laser assisted spalling process illustrated in Figure 19b is remarkably similar. The main difference is an additional laser processing step, in which a laser beam is focused on a defined plane or on a defined course in the sample, and then scans the sample. The laser layer generated in this way then defines the level of cracking and hence separation in the later spalling process.

19b thus shows the laser-assisted spalling process. In addition to the process steps shown in FIG. 19a, a structurally weakened layer is created in the material by means of a modification layer or laser system produced by means of laser beams in a further process step, which defines a preferred plane for spalling crack propagation.

A typical resulting wafer surface of laser-free spalling is in 19c shown. A pattern of Wallner lines results from the crack propagation inside the material. Grooves can be identified on the surface of the material that trace the cracking behavior along the parting line in the material. Cracks occur at the edges of the sample and migrate inward, creating a detailed pattern, as in 19c arises. The quadruple symmetry of the pattern is a consequence of four times the crystal symmetry in the silicon, with a singularity or center of the ripples in the middle of the sample. However, in order to technologically compete with wire sawing processes, surface quality after separation is of critical importance to any spalling process. However, the resulting total thickness variation (TTV) of spalling surfaces without a laser process is usually far beyond the industry requirements. The typical TTV of spalling processes is on the order of 50 microns, which would require grinding steps before further processing which would drive the cost too high. The use of the LAS process instead leads to surface roughness values of Sa <1 μm have been achieved. Sa is the arithmetic mean of the absolute values of the surface coordinates z (x, y).

19c Thus, Figure 1 shows a photograph of one half of a 300 mm silicon wafer after separation using conventional spalling. Wallner lines are clearly visible as tear grooves and indicative of high surface height variation (TTV).

19d shows a photograph of one half of a 300 mm silicon wafer after laser-assisted spalling. The surface is homogeneous with a surface roughness below 1 μm and no visible streaks from the crack propagation. The vertical line on the left side of the substrate comes from a limitation of the travel path of the substrate stage table of the laser system.

The 20a -F show an overview of the material surfaces after laser-assisted spalling. 20a shows a silicon surface of the in Sample shown, with a surface roughness of Sa = 0.79 microns. 20b shows a sapphire (Al ₂ O ₃ ) substrate surface (C-plane) after laser-assisted spalling, with a surface roughness of Sa = 1.96 μm. 20c and 20d show surfaces of silicon carbide polymorphs 4H and 6H (both with N-doping) after laser-assisted spalling with surface roughness Sa = 1.85 μm and Sa = 1.29 μm. 20e shows an example of spalling of non-crystalline material, surface of polycrystalline Al ₂ O ₃ , having a surface roughness Sa = 3.89 μm. 20f shows quartz glass, principle study, experiment of laser-supported spalling, with surface roughness of Sa = 6.89 μm.

21a shows a micrograph of a surface after spalling. 21b shows Raman spectra from three different sites in 6H silicon carbide. The Raman spectra from the darker area (on the right of 21a ) are curve K1 and curve K2, with the curve K3 being the Raman spectrum from the brighter region on the left side in FIG 21a , The peak height is reduced for the darker areas for almost all peaks and at the position 2 in the darker area no more Raman peaks are recognizable.

22 shows another additional or alternative beam profile. In a Brewster application with high numerical apertures, the beam profile of the laser can be adapted according to the invention. Thus, with high NA, more intensity can result in the flanks of the irradiated laser beam profile. At the extreme, this is a kind of donut profile with a clear intensity minimum in the middle. But it is also conceivable that the laser beam profile is designed as a flattened in the middle Gauss profile. It will Thus, the circumstance preferably exploited that at high NA, the edge regions of the laser profile can already come close to the Brewster angle. That through 22 Example profile shown could thus be generated preferably with relatively higher intensity proportion (compared to the other embodiments) in the flanks.

23a describes a first solid state generation configuration. According to this configuration, it is possible to use the solid state layer 14 from the solid 1 separate. According to this configuration, a first number of modifications 2 generated in the solid. The modifications 2 in this case preferably already cause a deflection of the split-off solid layer 14 , In 23b a second solid state generation configuration is shown. According to this configuration, it is also possible the solid state layer 14 separate from the solid. However, according to this configuration, a second number of modifications will be made 2 in the rectal body 1 generated. The second number of modifications 2 is preferably greater than the first number of modifications. Additionally or alternatively, it is possible that the configuration has multiple modification layers 2.1 . 2.2 or more modification layers 2.1 . 2.2 has as the first configuration in which also a plurality of modification layers can be provided. Additionally or alternatively, it is also conceivable that individual or the majority of the modifications 2 According to the second configuration are formed stronger than in the first configuration. In this case, more highly developed means that the individual modifications each extend over a larger volume than in the first configuration. The laser beams 10 preferentially penetrate in the longitudinal direction of the solid 1 or at an angle of up to 60 ° inclined to the longitudinal direction L of the solid 1 via a, in particular flat, surface, which is preferably part of the solid state layer, in the solid state 1 one and the crack guide area 4 is then preferred from several layers of modifications 2 educated. The layers are preferably spaced from each other in the longitudinal direction L or generated offset. At least several of the modifications are preferred 2 an extension in the longitudinal direction L, which is between 1 and 50 microns, and / or the laser beams 10 are preferred for producing the modifications 2 in the solid state 1 that the numerical aperture is less than 1, preferably less than 0.9 or less than 0.8 or less than 0.7 or less than 0.6 or less than 0.5.

Thus, the invention describes a method for separating at least one solid layer from a solid, wherein by the modifications a crack guide region for guiding a crack for separating a solid portion, in particular a solid layer, is predetermined by the solid, at least comprising the steps: moving the solid relative to a laser application device, successively generating laser beams by means of the laser application device for generating in each case at least one modification, wherein the laser application device is set for defined modification generation as a function of at least one parameter, in particular the transmission of the solid, at defined locations and for a defined solid body depth, wherein by the adjustment of the laser application device inhomogeneities of the solid in the region of the applied surface and / or in the region of Beaufs collapsed volume of the solid can be compensated, separating the solid layer of the solid.

LIST OF REFERENCE NUMBERS

1

solid

2

modification

3

Place of modification production

4

Crack guiding area

6

Solids

8th

Laserbeaufschlagungseinrichtung

9

lens

10

laser beams

11

Modified laser beams

12

deepening

14

Solid layer

16

Surface of the solid state layer

17

incident surface

18

Voltage generation layer

19

Adhesive or other voltage generation layer

24

local property change of the solid (eg the transmission)

26

dig

28

frame

30

Crossing point of the reflected rays

32

flush

34

coating

L

Longitudinal direction of the solid

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• Optical Properties of Spin-Coated TiO 2 Antireflection Films on Textured Single-Crystalline Silicon Substrates (Hindawi Publishing Corporation International Journal of Photoenergy, Volume 2015, Article ID 147836, 8 pages, http://dx.doi.org/10.1155/ 2015/147836) [0090]

Claims (20)

Method for separating at least one solid-state layer ( 14 ) of a solid ( 1 ), whereby the modifications ( 2 ) a crack guide area ( 4 ) for leading a crack to separate a solid portion ( 6 ), in particular a solid-state layer, of the solid ( 1 ), at least comprising the steps: moving the solid ( 1 ) relative to a laser applying device ( 8th ), successively generating laser beams ( 10 ) by means of the laser application device ( 8th ) for generating in each case at least one modification ( 2 ), wherein the laser application device ( 8th ) is set for the defined modification generation as a function of at least one parameter, in particular the transmission of the solid, at defined locations and for a defined solid body depth, wherein the adjustment of the laser application device ( 8th ) Inhomogeneities of the solid in the area of the surface acted upon and / or in the region of the charged volume of the solid can be compensated, separating the solid layer ( 14 ) of the solid ( 1 ). Method according to claim 1, characterized in that data on the parameter or on several parameters are provided in a data storage device and at least before the generation of the modifications ( 2 ) are supplied to a control device, wherein the control device, the laser application device ( 8th ) depending on the respective location of the modification to be produced ( 2 ). Method according to claim 1 or claim 2, characterized in that the laser beams ( 10 ) for the production of modifications ( 2 ) have more energy in regions of low transmission than in regions of high transmission, the laser application device ( 8th ) comprises means, in particular an acousto-optic modulator, for adjusting the laser beam energy. Method according to one of the preceding claims, characterized in that the solid state layer ( 14 ) as a result of modification generation along the crack guide region ( 4 ) of the solid ( 1 ) or the solid state ( 1 ) after the generation of the modifications ( 2 ) is thermally acted upon, in particular cooled, and as a result of the thermal loading, the solid state layer ( 14 ) of the solid ( 1 ) along the crack guide area ( 4 ) or a voltage generation layer ( 18 ), in particular a polymer layer, on the solid ( 1 ) is arranged or generated, wherein the polymer layer preferably on a surface of the separated solid layer ( 14 ), wherein the polymer layer is subjected to thermal stress, in particular cooled, whereby the polymer layer undergoes a change in its strength upon thermal application, as a result of which, due to the change in strength of the polymer layer, mechanical stresses in the solid state ( 1 ), wherein the mechanical stresses cause crack propagation along the crack guide region to separate the solid layer ( 14 ) of the solid ( 1 ) cause. Method for producing at least one at least partially curved or curved solid layer ( 14 ), at least comprising the steps: moving the solid ( 1 ) relative to a laser applying device ( 8th ), successively generating laser beams ( 10 ) by means of the laser application device ( 8th ) for generating in each case at least one modification ( 2 ) inside the solid, whereby through the modifications ( 2 ) a crack guide area ( 4 ) for leading a crack to separate a solid portion ( 14 ), in particular a solid-state layer, of the solid ( 1 ), the modifications increasing the pressure in the solid state ( 1 ), the solid-state layer ( 14 ) due to the pressure increase along the crack guide area ( 4 ) by a crack propagation from the solid ( 1 ), wherein at least a portion of the modifications ( 2 ) as part of the solid state layer ( 14 ) of the solid ( 1 ), the solid-state layer ( 14 ) due to the modifications ( 2 ) is converted into a curved or curved shape, which differs from the crack guide area ( 4 ) resulting surface portion of the solid state layer ( 14 ) is thus at least partially convex. Method according to claim 5, characterized in that the laser beams ( 10 ) in the longitudinal direction of the solid ( 1 ) or at an angle of up to 60 ° inclined to the longitudinal direction (L) of the solid ( 1 ) over a, in particular flat, surface, which is preferably part of the solid state layer, in the solid state ( 1 ) and the crack guide area ( 4 ) from several layers of modifications ( 2 ) is formed, wherein the layers in the longitudinal direction (L) spaced from each other or offset generated, and / or at least several of the modifications ( 2 ) have an extension in the longitudinal direction (L), which is between 1 and 50 microns, and / or the laser beams ( 10 ) for generating the modifications ( 2 ) in the solid state ( 1 ) that the numerical aperture is less than 0.8. Method for separating at least one solid-state layer ( 14 ), in particular a solid-state disk, ( 14 ) of a solid or donor substrate ( 1 ), comprising at least the steps of: providing a solid ( 1 ), Creating modifications ( 2 ) inside the solid ( 1 ) by means of LASER rays ( 10 ), whereby the modifications ( 2 ) a crack guide area ( 4 ), along which a separation of the solid-state layer ( 14 ) of the solid ( 1 ), removal of material of the solid ( 2 ), in particular for producing a circumferential depression ( 12 ), wherein the removal of material in the longitudinal direction of the solid takes place, wherein the material removal of the crack guide area ( 4 ), separating the solid-state layer ( 14 ) of the solid, wherein the solid in the crack guide area ( 4 ) is weakened by the modifications in such a way that the solid-state layer ( 1 ) as a result of material removal from the solid ( 2 ) or after the removal of material such a number of modifications is produced that the solid is weakened in the crack-guiding region in such a way that the solid-state layer ( 1 ) of the solid ( 2 ) or a voltage generation layer ( 18 ) on a surface which is inclined relative to the circumferential surface, in particular flat ( 16 ) of the solid ( 1 ) is generated or arranged and by thermal loading of the solid state layer ( 14 ) mechanical stresses in the solid ( 1 ), wherein the mechanical stresses cause a crack to separate a solid-state layer ( 14 ), which, starting from the surface of the solid exposed by the material removal, is formed along the modifications ( 2 ) or the solid after the generation of the modifications ( 2 ) is thermally acted upon, in particular cooled, and as a result of the thermal loading, the solid state layer ( 14 ) of the solid ( 1 ) along the crack guide area ( 4 ) replaces. A method according to claim 7, characterized in that the material removal, starting from an exposed, in particular flat, surface of the solid ( 1 ), in particular parallel to the peripheral surface of the solid ( 1 ), in the longitudinal direction (L) of the solid ( 1 ) and at least partially spaced from the peripheral surface of the solid ( 1 ) he follows. A method according to claim 7 or 8, characterized in that the material removal in the form of an at least partially continuously extending trench ( 26 ), the trench ( 26 ) preferably at least 30 microns or at least 100 microns or at least 500 microns or at least 1 mm from the peripheral surface is spaced. Method according to one of claims 7 to 9, characterized in that after the separation of the solid state layer ( 14 ) at least the solids content ( 28 ) of the solid ( 1 ), which is between the ditch ( 26 ) and the peripheral surface is formed, at least in sections, in particular by the thickness of the previously separated solid layer ( 14 ) or solid layers ( 14 ), abraded, in particular abraded, lobed, etched or polished. Method according to one of claims 7 to 10, characterized in that the material removal by means of laser ablation or water jet cutting or etching is effected. Method for separating at least one solid-state layer, in particular a solid-state disk, ( 14 ) of a solid or donor substrate ( 1 ), comprising at least the steps of: providing a solid ( 1 ), Adjusting a flow behavior of a between the solid and the laser application device ( 8th ), in particular in the region of the course of the radiation, gas, in particular air, for the prevention of dust accumulation in the region of the laser radiation, generating modifications ( 2 ) inside the solid ( 1 ) by means of LASER rays ( 10 ) a laser application device ( 8th ), whereby the modifications ( 2 ) a separation region or crack guide region is predetermined, along which a separation of the solid-state layer ( 14 ) of the solid ( 1 ) he follows. Separating the solid-state layer ( 14 ) of the solid ( 1 ), where the solid ( 1 ) in the crack guide area ( 4 ) by the modifications ( 2 ) is weakened such that the solid state layer ( 14 ) as a result of material removal from the solid ( 1 ) or after the removal of material such a number of modifications is produced that the solid is weakened in the crack-guiding region in such a way that the solid-state layer ( 14 ) of the solid ( 1 ) or a voltage generation layer ( 18 ) on a surface which is inclined relative to the circumferential surface, in particular flat ( 16 ) of the solid ( 1 ) is generated or arranged and by thermal loading of the solid state layer ( 14 ) mechanical stresses in the solid ( 1 ), wherein the mechanical stresses cause a crack to separate a solid-state layer ( 14 ), which, starting from the surface of the solid exposed by the material removal, is formed along the modifications ( 2 ) or the solid state ( 1 ) after the generation of the modifications ( 2 ) is thermally acted upon, in particular cooled, and as a result of the thermal loading, the solid state layer ( 14 ) of the solid ( 1 ) along the crack guide area ( 4 ) replaces. A method according to claim 12, characterized in that the adjustment of the flow behavior by supplying a fluid, in particular ionized gas, in the region of the beam path between a lens and the solid state ( 1 ) or the adjustment of the flow behavior by generating a negative pressure, in particular a vacuum, in the region of the beam path between a lens and the solid ( 1 ) he follows. Method for separating at least one solid-state layer, in particular a solid-state disk, ( 14 ) from a solid or donor substrate ( 1 ), comprising at least the steps of: providing a solid ( 1 ), where the solid ( 1 ) at least one coating ( 34 ) whose refractive index corresponds to the refractive index of the surface of the solid ( 1 ), on which the coating ( 34 ), is different, or wherein on the solid ( 1 ) a coating ( 34 ) whose refractive index is the refractive index of the surface of the solid ( 1 ), on which the coating ( 34 ) is different, generating modifications ( 2 ) inside the solid ( 1 ) by means of LASER rays ( 10 ) a laser application device ( 8th ), whereby the modifications ( 2 ) a crack guide region is predetermined, along which a separation of the solid layer ( 14 ) of the solid ( 1 ) he follows. Method according to claim 14, characterized in that the coating ( 34 ) is produced or produced by spin coating, wherein the coating ( 34 ) Nanoparticles, in particular of at least one material selected from the list at least consisting of silicon, silicon carbide, titanium oxide, glass, in particular quartz glass, or Al 2 O 3, having. Method according to one of claims 14 or 15, characterized in that several coatings ( 34 ) are arranged one above the other or are produced, their refractive indices being different from one another, preferably a first coating which is attached to the solid ( 1 ) is arranged or generated a larger refractive index than an additional coating, which is produced on the first coating. Method for separating at least one solid-state layer ( 14 ), in particular a solid-state disk, ( 14 ) of a solid or donor substrate ( 1 ), comprising at least the steps of: providing a solid ( 1 ), Creating modifications ( 2 ) inside the solid ( 1 ) by means of LASER rays ( 10 ) a laser application device ( 8th ), whereby the modifications ( 2 ) a crack guide region is predetermined, along which a separation of the solid layer ( 14 ) of the solid ( 1 ), wherein the laser radiation at Brewster angle or with a deviation in the range of -5 ° to + 5 ° from the Brewster angle irradiates the solid, separating the solid layer of the solid, wherein the solid body in the crack guide region ( 4 ) by the modifications ( 2 ) is weakened such that the solid state layer ( 14 ) as a result of material removal from the solid ( 1 ) or after the removal of material such a number of modifications ( 2 ) is generated such that the solid is weakened in the crack guide area such that the solid state layer ( 14 ) of the solid ( 1 ) or a voltage generation layer ( 18 ) on a surface which is inclined relative to the circumferential surface, in particular flat ( 16 ) of the solid ( 1 ) is generated or arranged and by thermal loading of the solid state layer ( 14 ) mechanical stresses in the solid ( 1 ), wherein the mechanical stresses cause a crack to separate a solid-state layer ( 14 ) arises, which, starting from the surface of the solid ( 1 ) along the modifications ( 2 ) or the solid state ( 1 ) after the generation of the modifications ( 2 ) is thermally acted upon, in particular cooled, and as a result of the thermal loading, the solid state layer ( 14 ) of the solid ( 1 ) along the crack guide area ( 4 ) replaces. A method according to claim 17, characterized in that a compensation device, in particular an optical element, such as a diffractive optical Element or a continuous wedge, for compensation of a spherical aberration resulting from Brewster angle radiation in the laser application device ( 8th ) is available. tion. Method for separating at least one solid-state layer ( 14 ) of a solid ( 1 ), whereby the modifications ( 2 ) a crack guide area ( 4 ) for leading a crack to separate a solid portion ( 6 ), in particular a solid-state layer, of the solid ( 1 ), at least comprising the steps: moving the solid ( 1 ) relative to a laser applying device ( 8th ), successively generating laser beams ( 10 ) by means of the laser application device ( 8th ) for generating in each case at least one modification ( 2 ), Separating the solid state layer ( 14 ) of the solid ( 1 ). Method according to claim 19, characterized in that the laser application device ( 8th ) for defined modification generation as a function of at least one parameter, namely the transmission of the solid ( 1 ) is set at defined locations and for a defined solid body depth, and / or where the modifications ( 2 ) a pressure increase in the solid state ( 1 ), the solid-state layer ( 14 ) due to the increase in pressure along the crack guide area due to crack propagation from the solid ( 1 ), wherein preferably at least a portion of the modifications ( 2 ) as part of the solid state layer ( 14 ) of the solid ( 1 ) and wherein the solid state layer ( 14 ) preferably due to the modifications ( 2 ) is converted into a curved or curved shape, which differs from the crack guide area ( 4 ) resulting surface portion of the solid state layer ( 14 ) is thus at least partially convex shaped and / or wherein the solid state ( 1 ) at least one coating ( 34 ) whose refractive index corresponds to the refractive index of the surface of the solid ( 1 ), on which the coating ( 34 ), is different, or wherein on the solid ( 1 ) a coating ( 34 ) whose refractive index is the refractive index of the surface of the solid ( 1 ), on which the coating ( 34 ), is different, and / or wherein the laser radiation in the Brewster angle or with a deviation in the range of -10 ° to + 10 ° from the Brewster angle to the solid state ( 1 ), comprising one or more of the steps: removal of material from the solid ( 1 ), in particular for producing a circumferential depression ( 12 ), wherein the material removal in the longitudinal direction of the solid ( 1 ), wherein the material removal of the crack guide area ( 4 ), or adjusting a flow behavior of one between the solid ( 1 ) and the laser application device ( 8th ), in particular in the region of the course of the radiation, gas, in particular air, for the prevention of dust accumulation in the region of the laser radiation ( 10 ).

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