Method and substrate for controlling the energy distribution introduced into a substrate using a linear focus of a laser beam

Abstract

The present invention relates to a method for controlling the energy distribution introduced into a substrate by means of at least one line focus of at least one laser beam, and to the substrate.

Description

Technical Field

[0001] The present invention relates to a method and a substrate for controlling an energy distribution introduced into a substrate using at least one linear focus of at least one laser beam.

Background Art

[0002] In order to separate a substrate along a separation plane, laser-based methods are known from the prior art, among others. Here, by introducing a modification into the substrate or removing material from the substrate using a curved linear focus of the laser along the planned separation plane, a curved side surface can be formed on the separated substrate portion. Then, separation is performed along the introduced damage.

[0003] However, these separation planes have the disadvantage that they are not symmetrically configured.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, an object of the present invention is to provide means that enable the reliable formation of a highly symmetric curved separation plane of a substrate. Additionally, an object of the present invention is to provide a substrate having symmetric side surfaces.

Means for Solving the Problems

[0005] This problem is solved by proposing, according to a first aspect of the present invention, a method for controlling an energy distribution introduced into a substrate using at least one linear focus of at least one laser beam, wherein the method includes a step of forming a linear focus in the substrate at least for each region, and a step of at least partially controlling the energy distribution in the substrate by influencing the laser beam using at least one phase mask.

[0006] Accordingly, the present invention is based on the surprising recognition that by depositing laser pulse energy around the apex of a curved linear focus, it becomes possible to reliably achieve a curved modification of the substrate material along the thickness region of the substrate. In particular, by using the method according to the present invention, it is possible to achieve a modification in the substrate material that is symmetrically formed around the apex.

[0007] In this regard, it has been recognized, inter alia, that by using a phase mask, the distribution of laser energy deposited in the substrate material, and thus the energy distribution within the material, can be controlled in a particularly reliable yet simple manner. By appropriately influencing the laser beam with the phase mask, it has been determined that the effect of being able to shift, so to speak, the intensity distribution of the linear focus along the trajectory of the laser focus in a vacuum or air is suitable for controlling the distribution of energy deposited in the material and thus improving the modification of the material. Therefore, the location of material damage, particularly the center of gravity, can be determined along the focus trajectory, and the material damage at the desired location can be arranged along the linear focus.

[0008] In the conventional method, the laser pulse energy is deposited along a focus trajectory shifted with respect to its apex. Therefore, in order to achieve sufficient modification along the entire thickness region of the substrate despite this, hitherto, in order to advantageously arrange the energy deposition at the center of the thickness region of the substrate, the focus of the laser beam (for example, an airy beam), and thus in particular the apex of the curved linear focus, also had to be shifted in the direction of one of the two outer surfaces of the substrate to be separated.

[0009] In other words, that is, hitherto, since more energy has been deposited above the apex, that is, approximately above the substrate, particularly in the direction of the outer surface facing the laser source, in order to advantageously place the energy deposition at the center within the depth region of the substrate, the apex of the linear focus had to be placed near the lower outer surface. Otherwise, the modification of the lower region would have been insufficient or at least only slight.

[0010] Accordingly, in the conventional manner, the separated substrate portion has a side surface whose course is not symmetric but rather has a vertex shifted towards one of the two outer surfaces.

[0011] The modification of the substrate material can be carried out, for example, in one embodiment, by directly or indirectly influencing the substrate material, at least partially within the substrate material, in particular by the energy introduced by a linear focus. In this case, strictly speaking, by the electromagnetic field of the laser, a part of the laser pulse energy is introduced into the substrate material and deposited therein in a distribution that depends on the beam geometry, the parameters of the laser and the substrate material.

[0012] Therefore, the present invention generally enables the control of the energy distribution within the material generated by a linear focus by locally shifting the energy distribution by influencing the laser beam using a phase mask.

[0013] In one embodiment, controlling the energy distribution includes controlling the spatial extent and / or the center of gravity of the energy distribution.

[0014] Therefore, this method is particularly advantageously suitable for surface structuring. Because this method enables the placement of the energy distribution along the linear focus at a desired position within the substrate.

[0015] Therefore, using a curved modification (including the removal or extrusion of a curved region from the material) generated by a curved linear focus within the substrate material, it is possible to influence or determine the curvature of the planned separation surface and thus also the curvature of the side surface of the substrate after separation. Therefore, by appropriately influencing the laser beam during the material modification period, a symmetric curvature course of the side surface of the substrate portion can be achieved.

[0016] Therefore, the proposed method preferably further includes the step of introducing at least one modification to the material of the substrate region along a linear focus formed and controlled with respect to the energy distribution and / or separating the substrate along a predefined separation plane by means of a plurality of such modifications. The modifications can include, for example, changes in the density, refractive index, stress value, mechanical integrity of the substrate material, and / or particularly the etching rate of acidic or alkaline. The modifications can also include, for example, removing substrate material from the substrate, replacing the substrate material, particularly compressing the substrate material against the surrounding substrate, and / or generating microcracks.

[0017] By selecting the orientation of the curvature of the linear focus such that the course of the curvature, particularly the acceleration direction of the curvature, does not extend parallel and / or perpendicular to the main extension direction of the planned separation plane, it is possible for the curvature of the separation plane and thus the curvature of the side surface of the substrate portion to be influenced or determined by the curvature of the linear focus.

[0018] Therefore, in one embodiment, preferably the curvature is not parallel to the planned separation line, but rather, for example, perpendicular to it.

[0019] In one embodiment, preferably the curvature of the side surface of the divided substrate portion, particularly the curvature along the direction perpendicular to the main extension direction of the side surface, is simultaneously determined by the arrangement of the linear focus in the substrate, particularly the orientation of the curvature.

[0020] Thus, in the present invention, it becomes possible for the first time to achieve a symmetric course of the curved separation plane immediately after the separation process mediated by the modified substrate region, without post-treatment steps such as polishing particularly for the purpose of edge shaping, and moreover it is possible even in substrates having a very large thickness, for example, a thickness exceeding 500 μm. This can be achieved by positioning the energy distribution around the apex of the focus trajectory.

[0021] This is because the deposition of laser pulse energy observed at a position deviated from the apex along the focal orbit can be compensated for by the effect using the phase mask. This results in the symmetrical manifestation of material modification being achieved. Among other things, along with this, a particularly reliable material modification that extends completely through the material can be achieved.

[0022] That is, by using a linear focus, the energy distribution can be introduced into the substrate material. In other words, by using a linear focus, the energy can be spatially dispersed and deposited within the substrate, and this dispersed energy can be controlled according to the present invention.

[0023] This makes it possible to achieve the symmetrical manifestation of the generated separation surface. This applies to thin substrate thicknesses, for example, from 10 μm to and / or up to 500 μm in thickness. Also, this similarly applies to substrate thicknesses of 500 μm or more, for example, a substrate thickness of 525 μm. For example, the substrate can have a thickness of 700 μm or more, 1 mm or more, 3 mm or more, 5 mm or more, or even a thickness of 7 mm or more.

[0024] Therefore, according to the solution means of the present invention, in particular, it becomes possible to flexibly set the position of the energy distribution with respect to the apex of the focal orbit, and thus the position and shape of the modification generated within the substrate material.

[0025] In one embodiment, the thickness of the substrate material is measured between the two main surfaces of the substrate.

[0026] Preferably, the substrate is transparent, particularly with respect to the wavelength of the laser beam, preferably in the visible wavelength region, IR wavelength region, and / or UV wavelength region.

[0027] Suitably, the substrate is made of or has a glass material. Alternatively or additionally, the substrate can also have or consist of glass ceramic, silicon, sapphire and / or fused quartz.

[0028] The linear focus is preferably a curved linear focus. This linear focus is alternatively or additionally the focus of an airy beam. Preferably, the linear focus is alternatively or additionally the focus of a laser beam of an ultrashort pulse laser having a pulse width of 10 ps or less, preferably 5 ps or less, preferably 3 ps or less, preferably 1 ps or less, preferably 0.5 ps or less.

[0029] The phase mask phase-modulates the laser beam.

[0030] In this case, the phase mask preferably affects the laser beam by imposing an additional optically non-uniform phase on the laser beam due to a change resolved in the lateral direction of the optical path length.

[0031] The phase mask may be realized, for example, as an exposure shape optical system, a diffractive optical element (DOE), an acousto-optic modulator (AOM), or a liquid crystal spatial light modulator on silicon (LCOS-SLM).

[0032] However, the phase mask may be fully or partially realized using other elements that enable a defined phase change.

[0033] In one embodiment, a DOE is used as the phase mask.

[0034] Therefore, the method is particularly well-suited for the field of separation and surface structuring of substrates, especially glass substrates. For example, the method is particularly well-suited for the preparation and / or implementation of separating such substrates into substrate parts.

[0035] Advantageously, affecting the laser beam can include or represent affecting it statically. "Affecting it statically" here means, for example, manifestations related to the spatial orientation, position, and / or spatial extension of the linear focus within the substrate, such as during and / or resulting from the control of the energy distribution within the substrate, in particular time-independent manifestations during and / or resulting from the influence on the laser beam. In other words, the manifestation of the linear focus does not change during the control, influence, and / or modification of the substrate.

[0036] For example, due to the static influence on the laser beam, at least, affecting the laser beam using at least one phase mask, in particular the offset of the laser beam on the phase mask can be set fixedly, and preferably, it can be set according to a constant pulse energy and / or pulse duration of the laser.

[0037] Advantageously, affecting the laser beam can include or represent affecting it dynamically. "Affecting it dynamically" here means, for example, manifestations related to the spatial orientation, position, and / or spatial extension of the linear focus within the substrate, such as during and / or resulting from the control of the energy distribution within the substrate, in particular time-dependent manifestations during and / or resulting from the influence on the laser beam. In other words, the manifestation of the linear focus changes at least temporarily in a time-dependent manner during the control, influence, and / or modification of the substrate.

[0038] For example, due to the dynamic influence on the laser beam, at least, affecting the laser beam using at least one phase mask, in particular the offset of the laser beam on the phase mask can be implemented in a time-dependent manner, and preferably, it can be implemented for a constant or variable pulse energy and / or pulse duration of the laser.

[0039] Alternatively or additionally, at least one phase mask is a phase mask having a cubic phase distribution or a higher-order, in particular odd-order, phase distribution, and / or the phase mask is arranged in the optical path of the laser beam in front of the substrate, and in particular it may be assumed that the center of gravity of the beam cross-section, which is present in the plane of the laser beam, preferably the phase mask, has an incidence point on the phase mask.

[0040] The cubic phase mask can be easily set up and provides a reliable means of controlling the energy distribution.

[0041] Odd-order (order 3 or higher) phase masks are advantageous because in this case, by laterally shifting the input beam on the optical system in the same direction, it is possible to shift the center of gravity of the focal energy distribution (and thus the energy distribution in the substrate) in the same direction along the trajectory and / or propagation direction of the laser beam.

[0042] Alternatively or additionally, the step of forming a linear focus includes in particular that the position of the apex of the curved linear focus is set along the depth region, preferably the thickness region, of the substrate, where preferably the position of the apex of the linear focus is set (i) centrally along the depth region of the substrate and / or (ii) along the depth region of the substrate with a particular vertical distance from the central position, in particular the vertical distance along the depth region is (a) more than 0.1%, preferably more than 1%, preferably more than 5%, preferably more than 10%, preferably more than 20%, preferably more than 30%, preferably more than 40%, preferably more than 45% of the thickness of the substrate and / or (b) less than 50%, preferably less than 45%, preferably less than 35%, preferably less than 25%, preferably less than 15%, preferably less than 10%, preferably less than 5%, preferably less than 3%, preferably less than 1% of the thickness of the substrate and / or (c) between 0.1% and 49%, preferably between 0.1% and 10% or between 1% and 40%, preferably between 5% and 30%, preferably between 10% and 25% of the thickness of the substrate, and it may also be assumed.

[0043] By positioning the vertex of the curved linear focus at the corresponding center, the trajectory of the linear focus extends symmetrically around the central plane of the substrate. This expands the possibility of introducing into the substrate a modification that extends symmetrically around the central plane of the substrate.

[0044] Therefore, further, for example, by appropriately influencing the energy distribution using a phase mask and positioning it symmetrically around the vertex, it is also possible to introduce into the substrate a modification that extends symmetrically around the central plane of the substrate.

[0045] However, in order to achieve the corresponding course within the substrate, it may be suitable to position the vertex offset with respect to the center. Here, it may be advantageous if the distance is measured as follows, that is, the (virtual) center position of the vertex along the depth region of the substrate is determined, the target position along the depth region of the substrate is determined, and the difference between the two positions of the vertex indicates the distance. When the depth region extends perpendicular to the outer surface of the substrate, it is also the vertical distance. That is, the offset that can occur at the vertex, such as for a curved linear focus in a direction extending perpendicular to it and thus horizontally, is not important at least for the vertical distance.

[0046] The direction "along the depth region" preferably extends perpendicular to at least one of the outer surfaces of the substrate here, and in particular extends perpendicular to the outer surface of the substrate facing the laser source.

[0047] Each of the described positionings of the linear focus and thus its vertex can be done, for example, by changing the distance between the focusing optical system used and the substrate. For example, for this purpose, the substrate and / or the focusing optical system can be translated along the beam propagation direction. Preferably, the laser beam is focused onto the substrate using the focusing optical system.

[0048] Alternatively or additionally, the positioning of the linear focus and thus of its apex can be done by adapting the focal length of the system, in which case preferably the numerical aperture of the system is maintained. For example, for this purpose the focusing optics has a multi-lens system with variable focal length.

[0049] The central plane is here preferably a plane which passes advantageously through the center within the substrate, i.e. the center between the two outer surfaces of the substrate, and whose normal vector extends parallel to the main extension direction of the laser beam.

[0050] In one embodiment, the position of the apex is set such that the apex is present outside the substrate.

[0051] Alternatively or additionally, the step of controlling the energy distribution within the substrate further includes setting the pulse energy, the pulse duration, the number of pulses within a burst, the energy distribution within a burst, and / or the laser wavelength, where preferably the pulse energy is set such that the linear focus within the substrate has at least one segment along which the substrate material is modified based on the energy deposited within the substrate, in particular by the interaction between the energy and the substrate material, where preferably the segment has (a) a length greater than 0.1 mm, preferably greater than 0.3 mm, preferably greater than 0.5 mm, preferably greater than 0.7 mm, preferably greater than 1 mm, preferably greater than 3 mm, preferably greater than 5 mm, and / or (b) a length less than 5 mm, preferably less than 3 mm, preferably less than 1 mm, preferably less than 0.7 mm, preferably less than 0.5 mm, preferably less than 0.3 mm, preferably less than 0.1 mm, and / or (c) a length between 0.1 mm and 5 mm, preferably between 0.5 mm and 2 mm.

[0052] It has been recognized that not only the phase mask affects the energy distribution, particularly their positions along the focal trajectory, but also the change in pulse energy can cause a change in the energy distribution, particularly a change in their shape such as their positions and / or spatial expansion along the focal trajectory. Therefore, the energy distribution can also be controlled via the pulse energy accordingly.

[0053] Similarly, as determined by the inventors, further parameters such as the pulse duration or the number of pulses within a burst and the wavelength of the laser beam can also be used correspondingly for control.

[0054] Preferably, the pulse energy is measured in front of the focusing optical system. Therefore, in this application, this should be advantageously considered under the corresponding value of the pulse energy unless something else is clear from each context.

[0055] Regarding this point, particularly for the position where the apex of a particularly curved linear focus is set along the depth region of the substrate, preferably the thickness region, the pulse energy can be selected such that the secondary maximum of the linear focus does not appear or appears only to a slight extent within the substrate. Specifically, for example, at the linear focus, that is, at the location of the maximum intensity along the propagation, the intensity of the primary maximum in the cross-section where the desired linear focus appears along the propagation is at least 1.1 times, preferably at least 1.3 times, preferably at least 2 times, preferably at least 3 times, preferably at least 5 times, preferably at least 7 times, preferably at least 10 times, preferably at least 20 times, preferably at least 30 times, preferably at least 50 times, preferably at least 100 times the maximum intensity of any secondary maximum in the same cross-section or along the entire propagation. It has also been recognized that it can be selected to be such.

[0056] It is advantageous to increase the contrast between the primary maximum that manifests the desired linear focus and all secondary maxima in the substrate. This is because it can reduce or eliminate their influence on material modification. In this way, the shielding effect caused by the secondary maxima can be prevented, and thus a particularly reliable linear focus can be achieved, and therefore a particularly reliable material modification can be introduced into the substrate.

[0057] In order to be able to introduce a modification into the substrate using a linear focus and the energy distribution introduced into the substrate by the linear focus, at the corresponding location, an energy density higher than a threshold value that depends particularly on the material is required. Therefore, it is advantageous if the energy distribution is adapted by an appropriately selected pulse energy, so that sufficient energy is deposited in the substrate to achieve the interaction between the energy and the material leading to the modification. If a high energy density is achieved within a spatially narrowly delimited volume, it can be particularly advantageous for the method according to the invention. Thereby, particularly advantageously, a modification that spatially narrowly delimits but causes a largely manifested damage to the material can be introduced into the substrate, thereby enabling easy separation of the substrate along the desired separation surface without weakening the sides of the separated substrate portions.

[0058] By adapting the pulse energy, for example, the length of the section of the linear focus that exceeds a specific threshold value of the energy density at every location can be changed, thereby enabling the generation of a modification (including material removal) that extends at least along that section within the material.

[0059] For example, the threshold value may depend on the material of the substrate.

[0060] By adapting the pulse energy, for example, the energy distribution, particularly the position where its center of gravity takes along the focus trajectory, can also be changed.

[0061] Therefore, the pulse energy is a supplementary means for controlling, in particular adapting, the energy distribution, such that a sufficiently high energy deposition takes place within the substrate material, for example with respect to the position of its center of gravity and / or with respect to the length of the linearly focused section along it.

[0062] Alternatively or additionally, (i) the pulse energy is at least temporarily (a) set to 50 μJ or more, preferably 100 μJ or more, preferably 200 μJ or more, preferably 300 μJ or more, preferably 400 μJ or more, preferably 500 μJ or more, preferably 600 μJ or more, preferably 1000 μJ or more, preferably 1500 μJ or more, preferably 2000 μJ or more, preferably 2500 μJ or more, preferably 3000 μJ or more, preferably 3500 μJ or more, preferably 4000 μJ or more, preferably 4500 μJ or more, preferably 5000 μJ or more, and / or (b) set to 5000 μJ or less, preferably 4500 μJ or less, preferably 4000 μJ or less, preferably 3500 μJ or less, preferably 3000 μJ or less, preferably 2500 μJ or less, preferably 2000 μJ or less, preferably 1500 μJ or less, preferably 1000 μJ or less, preferably 600 μJ or less, preferably 500 μJ or less, preferably 400 μJ or less, preferably 300 μJ or less, preferably 200 μJ or less, preferably 100 μJ or less, preferably 50 μJ or less, and / or (c) set between 50 μJ and 5000 μJ, preferably between 10 μJ and 100 μJ, between 100 μJ and 300 μJ, between 150 μJ and 300 μJ, between 200 μJ and 400 μJ, between 300 μJ and 600 μJ, between 600 μJ and 1000 μJ, between 800 μJ and 2000 μJ, between 1500 μJ and 3000 μJ, between 2000 μJ and 4500 μJ, or between 3000 μJ and 5000 μJ, and / or (ii) the pulse energy is set such that the average linear energy density is (a) Above 1 μJ / mm, preferably above 5 μJ / mm, preferably above 10 μJ / mm, preferably above 20 μJ / mm, preferably above 30 μJ / mm, preferably above 40 μJ / mm, preferably above 50 μJ / mm, preferably above 60 μJ / mm, preferably above 70 μJ / mm, preferably above 80 μJ / mm, preferably above 90 μJ / mm, preferably above 100 μJ / mm, preferably above 150 μJ / mm, preferably above 200 μJ / mm, preferably above 250 μJ / mm, preferably above 300 μJ / mm, preferably above 350 μJ / mm, preferably above 400 μJ / mm, preferably above 500 μJ / mm, preferably above 600 μJ / mm, preferably above 700 μJ / mm, preferably above 800 μJ / mm, preferably above 900 μJ / mm, and / or (b) Below 1000 μJ / mm, preferably below 900 μJ / mm, preferably below 800 μJ / mm, preferably below 700 μJ / mm, preferably below 600 μJ / mm, preferably below 500 μJ / mm, preferably below 400 μJ / mm, preferably below 350 μJ / mm, preferably below 300 μJ / mm, preferably below 250 μJ / mm, below 200 μJ / mm, preferably below 180 μJ / mm, preferably below 160 μJ / mm, preferably below 140 μJ / mm, preferably below 120 μJ / mm, preferably below 100 μJ / mm, preferably below 90 μJ / mm, preferably below 80 μJ / mm, preferably below 70 μJ / mm, preferably below 60 μJ / mm, preferably below 50 μJ / mm, preferably below 40 μJ / mm, preferably below 30 μJ / mm, preferably below 25 μJ / mm, preferably below 20 μJ / mm, preferably below 15 μJ / mm, preferably below 10 μJ / mm, preferably below 5 μJ / mm, and / or (c) It may be assumed to be between 1 μJ / mm and 200 μJ / mm, particularly between 10 μJ / mm and 120 μJ / mm, preferably between 10 μJ / mm and 50 μJ / mm, between 40 μJ / mm and 80 μJ / mm, between 70 μJ / mm and 100 μJ / mm, or between 80 μJ / mm and 120 μJ / mm.

[0063] The proposed pulse energy and average linear energy density are particularly suitable for glass substrates.

[0064] If burst pulses are used, the pulse energy and the burst energy can preferably be mutually converted according to the following relational expression: burst energy = pulse energy × number of pulses in the burst. For example, when the pulse energy is 50 μJ and the number of pulses N = 2 in the burst, the burst energy is 50 x 2 μJ = 100 μJ, and vice versa. Therefore, that is, by setting the burst energy, the pulse energy can also be set accordingly.

[0065] Preferably, the average linear energy density is defined as the quotient of the laser pulse energy and the thickness of the substrate. Alternatively, the average linear energy density may preferably be defined as the quotient of the laser pulse energy and the length of the modification in the substrate.

[0066] The inventors preferably start from the fact that in order to generate a modification in the form of a change in the local refractive index of a material, for example in borosilicate glass, using an airy beam, a local linear energy density of 1 μJ / mm or more is required, that is, the energy density integrated on a plane perpendicular to the laser propagation direction.

[0067] Alternatively or additionally, the step of controlling the energy distribution in the substrate includes (a) adapting the spatial expansion of the energy distribution, (b) adapting, in particular shifting, the position of the maximum material damage caused especially by the non-linear interaction between the laser and the substrate material, and / or (c) adapting, in particular shifting, the position of the energy distribution, in particular the position of the preferably global maximum of the energy distribution and / or the position of the center of gravity of the energy distribution, preferably along the trajectory of the laser beam, in particular the trajectory of the linear focus. In this case, preferably (i) After adapting the position of the energy distribution, at least one maximum of the energy distribution is positioned, in particular at the apex of the curved linear focus, and / or (ii) After adapting the spatial extension and / or position of the energy distribution, a modification of the substrate material extending along the entire substrate thickness is carried out or performed, and / or (iii) Adapting the position of the energy distribution may be assumed to include successively and continuously adjusting at least in part the influence on the laser beam using a phase mask and the setting of the pulse energy.

[0068] By shifting the maximum value of the energy distribution, the location of the (maximum) modification can be determined with particularly high reliability. Thereby, for example, it becomes possible to prepare and / or subsequently carry out a planned separation process in the substrate with high reliability.

[0069] By positioning the maximum value of the energy distribution within the substrate material at the apex, a symmetric modification around the apex can be introduced into the substrate. Optionally, by positioning the apex symmetrically on its own side within the thickness region of the substrate, such a separation surface can be obtained, along with the sides of the separated substrate portions having a symmetric course (in particular, in the cross-section extended by the normal vector of the outer surface of the substrate and the normal vector of the planned separation surface).

[0070] In an embodiment, particularly preferably, the influencing using the phase mask and the setting of the pulse energy are adjusted successively and continuously. Thereby, the spatial extension and / or position of the modification within the substrate can be controlled very flexibly.

[0071] For example, the pulse energy can be selected such that a high energy deposition exists along a linear focus within the entire thickness region of the substrate, so that material modification can be generated along the entire thickness region at any location along the linear focus. This may be necessary, for example, to achieve modification within the substrate along the entire thickness region. At the same time, due to the influence adjusted there using the phase mask, the position of the energy distribution is adapted such that, for example, its maximum value exists at the apex of the focus trajectory. Thereby, it becomes possible to achieve a symmetric modification (e.g., with respect to the plane of the substrate where the apex of the focus trajectory also exists, particularly the central plane) of the substrate material along the entire thickness region.

[0072] In one embodiment, the location of the maximum modification of the substrate is at the apex of the linear focus trajectory and / or at the center along the thickness region of the glass substrate.

[0073] Alternatively or additionally, influencing the laser beam using at least one phase mask includes the laser beam being incident offset with respect to the center point of the phase mask, where the center point is the location of the phase mask where the laser beam incident on the phase mask having a diameter approaching zero is affected by the saddle point of the phase distribution imposed on the phase mask, and where preferably the offset is performed within the mirror plane of the phase distribution, and where preferably the offset is between 0.1 μm and 5000 μm, preferably between 1 μm and 3000 μm, preferably between 1 μm and 2000 μm.

[0074] A particularly simple and reliable way to influence the laser beam is to make the laser beam incident on the phase mask at different positions. This is because the phase mask influences the laser beam, particularly with respect to the energy distribution at the focus, depending on where the laser beam is incident on the phase mask. Preferably, the incident point here can be understood as the centroid of the beam cross-section existing within the plane of the phase mask.

[0075] Therefore, especially for cubic phase masks, as the offset of the incident point of the laser beam (more precisely, the centroid of its cross-section in the plane of the phase mask) from the center point of the phase mask increases (especially when the offset occurs within the mirror plane of the phase distribution), in the substrate, the location of the maximum energy on the focal trajectory moves away from the apex, and it has been determined that it moves away in one direction or the other along the trajectory depending on the sign of the offset.

[0076] When referring to the center point of the phase mask in the present application, it should be understood here that, preferably, it means the location of the phase mask where the laser beam incident on the phase mask having a diameter approaching zero is affected by the saddle point of the phase distribution imposed on the phase mask.

[0077] The phase distribution, and thus the location of the saddle point of the phase distribution on the phase mask, can also be determined, for example, using a microscope. Alternatively, the location of the saddle point can also be determined experimentally, in which case, for example, a laser beam (or its centroid in the beam cross-section on the phase mask) is incident on the phase mask at different positions, and the following location of the phase mask, i.e., the location where the laser beam passing through the phase mask is affected such that, during proper imaging in linear propagation (measurable by a microscope construction or an aberration pattern on the substrate surface), the maximum intensity is achieved at the apex of the parabola and / or the intensity distribution is symmetrically distributed around the apex and the secondary maxima are symmetrically manifested in front of and behind the focus, is identified as the center point. Or, in other words, linear propagation corresponds to an ideal Airy beam.

[0078] Preferably, the saddle point, and thus also the center point, is present at the geometric center point of the phase mask. This can be achieved, for example, by a phase function placed at the center.

[0079] Preferably, the change in the depth of the maximum value of the energy distribution with respect to the offset dx is given by the following equation:

Equation

[0080] Therefore, this enables the proposed method to generate a focus shift due to a lateral beam offset and simultaneously utilize this focus shift for controlling the energy distribution.

[0081] That is, preferably, the influence of the offset of the laser beam on the phase mask (especially of a cubic crystal) on the position of the maximum of the focus intensity can be observed, and thus the influence on the energy distribution in the substrate along the focus trajectory can also be effectively observed.

[0082] Thereby, preferably, as the offset of the input beam on the phase mask from the center of the phase mask and / or within the symmetry plane of the phase distribution increases, the location of the maximum of the energy distribution shifts with respect to (i) the apex of the linear focus trajectory, and / or (ii) the point on the linear focus trajectory that coincides with the apex of the linear focus generated by an input beam whose tangent is parallel to and centered on the optical axis.

[0083] Therefore, preferably, the linear focus is the focus of an airy beam and / or at least, by affecting the laser beam using at least one phase mask, the location of the maximum of the energy distribution is shifted with respect to the apex of the airy trajectory generated by an input beam centered in particular, and preferably, is shifted along the airy trajectory.

[0084] Therefore, preferably, the linear focus is the focus of the airy beam and / or at least by affecting the laser beam using at least one phase mask, the location of the maximum value of the energy distribution is shifted relative to the apex of the orbit of the linear focus and, preferably, is shifted along the orbit of the linear focus.

[0085] Alternatively or additionally, (i) the offset is (a) by moving the phase mask relative to the laser beam and / or (b) by at least one rotating parallel plate made of an optical material that is particularly transmissive at the glass material and / or preferably at the laser wavelength and / or (c) by at least two prisms arranged one behind the other in the optical path, the prisms preferably having the same prism angle and preferably the second prism being arranged rotated 180° about the optical axis relative to the first prism and / or (d) set by moving a deflection mirror that deflects the laser beam, particularly in the optical path and / or parallel to the direction of the incident beam, and / or (ii) the offset is preferably set by deflecting a laser beam that extends parallel to and / or along the central axis of the phase mask using at least one first means, whereby the direction vector of the beam incident on the phase mask forms an angle with the direction vector of the central axis of the phase mask, preferably the angle being 1 / 500 radians or less, preferably 1 / 1000 radians or less, preferably 1 / 2000 radians or less, Preferably, the deflection is (a) at least one prism supported rotatably, (b) at least one mirror supported rotatably, (c) at least one polygon or galvoscan, (d) at least one acousto-optic modulator, (e) At least one liquid crystal spatial light modulator on silicon, and / or (f) Set using a first means having at least one microelectronic mirror component, Preferably, a second means identical to the first means is further provided, so that the laser beam is incident perpendicularly to the phase mask and / or the substrate, and / or is parallel to but offset from the path before deflection using the first means, and is arranged in the optical path in front of or behind the phase mask and / or is assumed to be controlled in synchronization with the first means to deflect the laser beam.

[0086] Therefore, two particular principles for setting the offset are particularly suitable. In one case, the laser beam is incident parallel to the central axis of the phase mask (alternatively, also parallel to the optical axis of the system used for focusing, including a focusing optical system such as a phase mask, a microscope objective lens, or an aspherical lens). In another case, the laser beam is incident at an angle to the central axis of the phase mask.

[0087] In the latter case, by correcting the angle using the same means, the oblique beam path (with respect to the central axis of the phase mask) can be reversed again so to speak. Therefore, the beam is offset in the result by the first and second means, but passes along the parallel direction in front of the first means and behind the second means.

[0088] Particularly when the lateral offset of the input beam on a cubic phase mask is generated by a rotated parallel plate, the maximum achievable offset can be very easily adapted by the thickness, refractive index, and lateral expansion of the parallel plate with respect to the diameter of the laser beam.

[0089] When offsets are achieved by two prisms that are present one after the other in the optical path and have the same prism angle, the achievable offset can be very easily adapted by the size of the prism relative to the diameter of the laser beam, the deflection angle of the prism, and the maximum distance between the prisms. For example, the size, angle, and distance may be selected as follows. A prism size between 10 mm and 60 mm (or a size exceeding 60 mm), preferably between 10 mm and 26 mm, particularly the diameter; a deflection angle according to the formula x = sin(th)*d, where x is the lateral beam offset, th is the deflection angle, and d is the distance of the prism; a distance between 1 mm and 200 mm (or a distance exceeding 200 mm).

[0090] When an offset is achieved by translating a deflection mirror within the optical path, a translation parallel to the direction of the incident beam is particularly advantageous. This is because thereby the maximum offset is not limited by the size of the optical system.

[0091] These optional features preferably produce a pure lateral offset without changing the beam direction.

[0092] In particular, when the deflection is sufficiently small and the available distance to the phase mask is sufficiently long (for example, 100 cm or more, preferably 150 cm or more, preferably 200 cm or more, preferably 300 cm or more, preferably 400 cm or more), the desired effect of the offset can also be achieved in a particularly reliable manner by changing the angle of the input beam.

[0093] The setting of the deflection using a scanner or an acousto-optical modulator (AOM) is particularly suitable. This is because these components are basically suitable for achieving significant deflection even in the case of short pulse intervals within a laser burst, for example, based on their short response times. This enables, for example, particularly reliable in-flight correction of substrates, especially using a plurality of offset laser pulses, each of these laser pulses correcting the substrate in separate depth segments on a continuous track within the substrate, especially during a structuring process, without a change in the axial speed, braking, or stopping. This applies in particular when the substrate moves at a speed of 2 m / s or less relative to the line focus and / or with an intra-burst pulse interval of 25 ns or less. Here, for example, the diameter of the correction itself (e.g., 1 to 10 μm) can be used as a comparison size.

[0094] As already described above, a pure lateral offset can be achieved using the proposed means of deflecting the beam by deflection at two positions existing one after the other in the optical path, where the angle generated by the first deflection is compensated by using a second deflection. In this case, preferably, the synchronization between the deflection elements is taken into account.

[0095] Alternatively or additionally, influencing the laser beam using at least one phase mask is carried out in a time-dependent manner, whereby it may be assumed that the energy distribution, in particular its shape and / or position, changes in a time-dependent manner.

[0096] By exerting a time-dependent influence, the energy distribution can be moved, for example, along the track of the focus within the material. Thus, advantageously, in one embodiment, the maximum value of the energy distribution is shifted in time, thereby enabling the correction of the substrate to be carried out with high reliability even along a large thickness region.

[0097] This is advantageous, for example, when a linear focus cannot provide a sufficiently high energy distribution in the substrate material along the full thickness region in order to introduce a modification into the substrate material.

[0098] Thereby, it is possible to move within the substrate an energy distribution that reaches or exceeds the threshold required for the modification along a section of the focus trajectory.

[0099] For example, even if the pulse energy is not sufficient to achieve an energy density greater than the threshold required for the modification along the full thickness region, this is nevertheless a reliable and simple means by which the symmetric parting surface itself can be designed with a thickness of corresponding size.

[0100] That is, this is advantageously a case of applying a dynamic influence.

[0101] Alternatively or additionally, the laser beam can be affected by different, preferably directly successively consecutive regions of the phase mask during different periods, and it is assumed that the laser beam, in particular the center of gravity of the beam cross-section present in the plane of the phase mask, has different entry points into this phase mask during different periods.

[0102] For example, for this purpose, an offset, that is, the entry point of the laser beam on the phase mask (or the entry point of the center of gravity of the beam cross-section present in the plane of the phase mask), can be controlled in time. For this purpose, the means described above are suitable for changing the offset as a function of time.

[0103] For example, the phase mask can be moved relative to the laser beam as a function of time, whereby, preferably, the offset in the horizontal symmetry plane of the phase distribution is different at different times.

[0104] Alternatively or additionally, it may be envisaged that, by being subject to time-dependent effects, the energy distribution within the substrate, preferably at least one maximum of the energy distribution, is moved, in particular from a greater depth to a lesser depth and / or along the focal track within the substrate.

[0105] In addition to the general means described above of shifting the energy distribution, thereby enabling even large thickness regions to be corrected, alternatively or additionally, it is advantageous to generate the correction within the substrate by a corresponding movement of the energy distribution, or its maximum or centroid, for example from below upwards, i.e. in particular from the side of the substrate facing away from the laser to the side of the substrate facing the laser. Thereby, preferably, the location of the current correction is shifted from the location of the previous correction. Thus, the line focus at the current location is not affected by the corrections already introduced into the substrate. Thereby, the correction can be introduced into the substrate with a very high level of reliability.

[0106] In the substrate, "below" may here be the location furthest from the laser source through which the laser beam passes within the substrate in the beam direction. In the substrate, "above" may here be the location closest to the laser source through which the laser beam passes within the substrate in the beam direction.

[0107] Therefore, the pulses of the beam source can also preferably be split into two or more temporal parts which are incident on the phase mask at different locations with a slight temporal offset. That is, for this purpose, a single pulse is temporally split, for example, the first part being deflected to the first position of the phase mask and the second part being deflected to the second position of the phase mask. In this case, the deflection can preferably be achieved by one of the means described above, in particular via separate beam paths (if it is a fixed structure, preferably also via mirrors). Alternatively or additionally, the SSTF described below is also suitable in this context.

[0108] Therefore, even when the pulse energy is sufficient for modification throughout the full depth of the material, this type of dynamic focusing can be highly advantageous. This is because, in such situations, the advantage of dynamic focusing lies in the fact that the manifestation of material modification in the lower part of the substrate is not inhibited by the plasma in the upper part of the substrate.

[0109] However, this form of dynamic focusing may also be particularly notable when the available pulse energy is not sufficient to modify the substrate in one pass along its full thickness.

[0110] This is because, not only in the case of thick substrates, but quite generally, the total damage zone can be composed of a plurality of single sub - modifications within the substrate, each achieved in particular by a laser pulse at a different position on the cubic phase mask. In this case, particularly advantageously, it is initiated with a single sub - modification at the deepest point within the substrate material (the point furthest from the laser source in the beam direction), and the position within the substrate is sequentially increased.

[0111] Therefore, the proposed method is suitable for substrates having a thickness of exactly 500 μm or more, preferably 1 mm or more, preferably 3 mm or more, preferably 5 mm or more, preferably 7 mm or more.

[0112] As a result, a smaller laser source can be used.

[0113] Alternatively or additionally, influencing the laser beam using at least one phase mask is assumed to include the intensity distribution of the laser beam changing, particularly within the pulse duration, on the phase mask, particularly at the point of incidence of the beam on the phase mask, and particularly changing spatially shifted on the phase mask.

[0114] Thus, so to speak, the elliptical region on the phase mask is illuminated differently depending on time. Since this can be done by modulating the laser beam intensity rather than with mechanical movement, it can be associated with very high reliability. Additionally, undesired effects that interfere with or inhibit the intended setting of the energy distribution within the material can be inhibited by controlling the temporal evolution of the energy distribution within the material.

[0115] Therefore, this simultaneous spatio-temporal pulse shaping (SSTF) is highly suitable.

[0116] Alternatively or additionally, using the energy distribution introduced with at least a part of a linear focus, (a) the substrate is modified at least region by region in terms of material properties such as, in particular, its density, its refractive index, its stress value, and / or its etching rate, (b) microcracks are generated at least region by region in the substrate material, and / or (c) material is removed from and / or extruded from the substrate at least region by region, where preferably, in a plurality of sequentially consecutive substrate regions, the substrate material is thus modified, removed, and / or extruded along a straight or arbitrarily shaped contour, and in particular it may be assumed that the substrate material is pressed into the surrounding substrate material.

[0117] That is, by changing one property within the substrate material, a planned separation surface is determined. Accordingly, the corresponding side surfaces of the substrate part are also thereby determined.

[0118] Removing the substrate material from the substrate can be done, for example, by evaporating the material. Extrusion of the substrate material can be done, for example, by pressing the substrate material into the surrounding substrate.

[0119] Therefore, a controlled energy distribution can generally be regarded as a means by which modifications including material removal or extrusion within the substrate material are achieved. This is because the energy distribution interacts with the substrate material in a way that is not further considered here and is not relevant to the understanding of the present invention, thereby resulting in the final modification.

[0120] By performing corresponding procedures in a plurality of regions of the substrate, a plurality of modified regions or regions where the substrate material has been removed / extruded can be achieved. Thereby, so to speak, a damaged corridor portion is preset, and at the same time a planned separation plane is determined. For example, mechanical or thermal action on the substrate can cause and / or effect the separation of the substrate into two substrate portions along the planned separation plane. For example, cracks can be generated in the corridor portion and propagated therein. Alternatively or additionally, an IR laser can be irradiated onto the substrate to initiate and / or effect the separation process. The CO2 stage is also a suitable means for effecting the separation of the substrate.

[0121] Different regions can be selected by the relative shift of the substrate and the linear focus. If it takes a time much longer than the pulse duration of the laser to shift the substrate by 1 centimeter (for example, more than 100 times), the shift can preferably be performed continuously. Alternatively or additionally, the maximum allowable movement speed v can be determined using the following relational expression v = modification_size / Pulsabstand where "modification_size" is the maximum extension of the modification introduced into the substrate material, and "Pulsabstand" is the intraverse pulse interval (for example, 40 MHz), and in the case of individual pulses, it is the interval between two sequentially consecutive pulses (for example, 1 / 100 kHz).

[0122] Preferably, the shift is performed continuously at a speed of 10 m / s or less, preferably 5 m / s or less, preferably 2 m / s or less.

[0123] Here, the contour is to be understood as meaning a curve representing the point of incidence of the laser beam on the surface of the substrate. The contour may be, for example, a straight line or circular, or alternatively may have another, in particular any curved course.

[0124] In one embodiment, in particular in a cross-section perpendicular to the main extension direction of the modification, in particular, the maximum diameter of the material modification or the maximum diameter of the region where the material is removed or extruded is between 1 μm and 100 μm, preferably between 1 μm and 50 μm, even more preferably between 1 μm and 20 μm, and even more preferably between 1 μm and 10 μm.

[0125] Alternatively or additionally, two or more linear foci of two or more laser beams within the same region of the substrate are preferably formed at least partially parallel to each other and / or at least partially continuously in time, and the energy distributions introduced into the substrate by them are correspondingly controlled, where preferably, (a) the energy distributions introduced by the individual linear foci are different, in particular with respect to position and / or shape, in which case preferably, the maxima of the individual energy distributions are at different positions within the substrate, and / or (b) it may be assumed that the trajectories of the two or more linear foci are congruent.

[0126] When multiple laser beams are used, even for thick substrates, individual modifications can be performed very quickly. That is, here, in order to affect the individual laser beams, in particular to shift the energy distribution or its maximum value within the substrate, it is not necessary to mechanically move the components of the optical structure. Instead, for example, the first laser beam can have a maximum value of the energy distribution in the lower region of the modification, and the second laser beam can have a maximum value of the energy distribution in the information region of the modification (where "upper" preferably refers to the location where the laser beam is incident on the substrate).

[0127] In one embodiment, multiple beams are used to modify the substrate in parallel at two or more positions spaced apart from each other in the lateral direction.

[0128] When beams from different laser sources, in particular pulses, are used, the laser sources are preferably similar laser sources. Thereby, a particularly uniform modification can be achieved.

[0129] Alternatively or additionally, the orientation of at least one section of the linear focus within the substrate is set by controlling the energy distribution within the substrate relative to the main propagation direction of the laser beam within the substrate and further adapting the focal position within the substrate material, where preferably the adaptation of the focal position is performed by changing the distance between the focusing optical system and the substrate and / or the thickness of the substrate is less than half the length of the linear focus potentially possible for a given optical structure along the thickness extension direction of the substrate, where preferably the pulse energy and / or the beam diameter may be assumed to be selected such that the substrate is modified over its entire depth or not over its entire depth.

[0130] Since the distance from the apex of the focus trajectory, in particular the airy focus trajectory, to the maximum of the energy distribution is accompanied by a change in the local arrangement of the linear focus with respect to the beam propagation direction or the substrate surface, in a preferred embodiment, as described above, a combination of beam offsets is used while at the same time adapting the focal position within the substrate material, i.e., for example, changing the distance between the focusing optical system and the substrate as described above or changing the focal length of the focusing optical system, to adapt the angular arrangement of the damage zone within the material.

[0131] In this way, in the case of thin glass, a small section of the airy trajectory can be used to generate at least a substantially straight linear focus at an angle with respect to the propagation direction.

[0132] Thereby, advantageously, by adapting the focal position within the substrate material, in particular by changing the distance between the focusing optical system and the substrate, it is possible to set the translation of the linear focus within the substrate, and / or by adapting the beam offset in any of the optical systems such as the phase mask and / or the focusing optical system, it is possible to set a free orientation within at least a predetermined angular range of at least one segment of the linear focus within the substrate relative to the main propagation direction of the laser beam within the substrate.

[0133] Together with the orientation of at least one segment of the linear focus, advantageously, the orientation of the modification introduced into the substrate material also changes. Thereby, preferably, by adapting the offset, it is possible to achieve the inclination of the modification within the substrate material, and / or by adapting the focal position, it is possible to compensate for the offset along the laser propagation direction with an inclination, and / or it is possible to adapt and / or set the vertical position of the inclined modification.

[0134] The "inclination" of the modification in the substrate material is here preferably understood to mean a modification having a spatial orientation different from the spatial orientation of a particular conceptual reference modification introduced into the substrate material under specific boundary conditions related to the optical structure and the laser parameters. In this case, the reference modification can be introduced into the substrate material under the same boundary conditions otherwise, under the offset of the laser beam set on the optical system such as the phase mask and / or the focusing optical system.

[0135] That is, advantageously, the inclination of the modification introduced into the substrate can be set and / or achieved by shifting the energy distribution along the trajectory of the linear focus. Alternatively or additionally, an inclination due to the inclination of the substrate, especially when it is stationary, may also be considered.

[0136] Here, preferably, when the adaptation of the focal position within the substrate material is carried out depending on time, in particular the focal position within the substrate material changes depending on time. This can be done, for example, by a time-dependent change in the distance between the focusing optics and the substrate. Thus, here, advantageously, it is an application example of a dynamic influence. Optionally, it may also be suitable to adapt the beam offset on the optical system, such as a phase mask and / or focusing optics, in parallel. That is, the focal position and the offset are advantageously adapted depending on each other.

[0137] Advantageously, the slope of the material modification is set and / or implemented by a shift of the intensity maximum of the energy distribution along the trajectory of the linear focus. Thereby, an asymmetric manifestation of the material modification can be compensated.

[0138] Here, preferably, the thickness of the substrate along which the linear focus is formed is less than at least half of the extension of the focal trajectory in the theoretical and / or practically available glass thickness direction.

[0139] For example, a substrate having a thickness of 500 μm or less, preferably 300 μm or less, preferably 100 μm or less, preferably 50 μm or less is particularly suitable here. Alternatively or additionally, the thickness can also be between 300 μm and 1000 μm.

[0140] A curved linear focus can be generated, in particular using the means described above, for example with a length of more than 0.1 mm to more than 3 mm, preferably between 0.1 mm and 5 mm, in particular between 0.5 mm and 3 mm, and / or with a maximum deflection from the straight focal line that can be generated between 500 μm, preferably between 10 μm and 200 μm, in particular between 20 μm and 80 μm.

[0141] The spatial shape of the curvature, and thus the spatial shape of the substrate material affected, may depend on or be determinable simultaneously with this maximum deflection, which may also be referred to as profile displacement.

[0142] To set the maximum deflection or profile displacement, the numerical aperture A = n * sin(ALPHA) of the focusing optical system can be set and / or adapted. Generally, here, the shorter the focal length of the formed focus as the focusing optical system with a larger numerical aperture is selected, and in the typical case of an airy beam, it holds that the curvature of the airy beam near the focus becomes higher.

[0143] In the case of a curved linear focus, this means that the thinner the substrate thickness, the more the local curvature of the linear focus needs to increase in order to generate a significant profile displacement at the separation surface.

[0144] Alternatively or additionally, (i) the linear focus is the focus of the airy beam, (ii) the linear focus has a maximum deflection from a straight path of more than 20 μm, more than 40 μm, more than 60 μm, more than 80 μm, or more than 100 μm, (iii) the laser beam is emitted by a pulsed laser, (iv) the wavelength of the laser beam is selected from the wavelength range between 200 nm and 1500 nm, preferably the wavelength is 343 nm, 355 nm, 515 nm, 532 nm, between 750 nm and 850 nm, 1030 nm and / or 1064 nm, and preferably the microscope objective or the Fourier lens of the focusing optical system that focuses the laser beam onto the substrate has a focal length of 10 - 20 mm, The coefficient of the cubic phase (laser parameter β) has a value between 0.5×10 3 / m and 5×10 3 / m, The diameter of the raw beam (laser parameter ω0) has a value between 1 mm and 10 mm, preferably between 2.5 mm and 7.5 mm, preferably between 2.5 mm and 5 mm, The pulse duration (laser parameter τ) has a value of 0.1 - 10 ps, The pulse energy (laser parameter Ep) has a value between 1 and 1,500 μJ, preferably between 30 and 500 μJ, particularly 474 μJ, and / or the number of pulses within a burst (laser parameter N) has a value between 1 and 200, preferably between 1 and 100, particularly between 1 and 8, and / or (v) The pulse energy of the laser is sufficient to modify the substrate in at least one material property along a specific section of the linear focus or to remove or extrude material from the substrate, where the section may be assumed to be shorter than the extension of the substrate area to be modified or removed or extruded in that material property.

[0145] The airy beam is generated with high reliability and has a curved linear focus.

[0146] The laser beam having a linear focus used herein can be deflected and controlled along the optical path using known means. The linear focus can be set and adapted using different means such as optical elements. Thus, an electromagnetic field can be generated within the substrate body, and this electromagnetic field can take on each spatial shape achievable using means for beam shaping and beam influence. Preferably, an airy beam is generated.

[0147] Therefore, a laser beam having a linear focus represents a very flexible means for modifying the substrate in a curved region.

[0148] When processing a substrate body using a laser, generally, it is necessary to distinguish between a linear absorption process and a non-linear absorption process. Linear absorption exists when the material to be processed is partially or completely absorptive with respect to the wavelength of the laser used (for example, the absorption of a CO2 laser beam in glass), so the intensity of the interaction can be appropriately set through the laser wavelength, laser energy, pulse duration, etc. This is to be distinguished from the non-linear absorption process where the material to be processed is initially non-absorptive within the area of the laser beam used, that is, transmissive with respect to the laser wavelength. However, the generation of so-called ultrashort laser pulses (in this case, the typical pulse length varies in the region of 10 ps to 100 fs, especially in the region of 1 ps to 100 fs) can generate a sufficiently high intensity by the laser within the substrate material in relation to non-linear optical effects. These effects include, for example, changes in the effective refractive index or the generation of plasma within the substrate material. Here, when sufficient energy is deposited in the material in an appropriate distribution, the laser beam has a permanent impact on the material. The resulting local changes in the material extend from permanent changes in the refractive index, changes in etching characteristics (selective laser etching), to the generation of cracks and channels within the substrate, and are limited to at least one region of the laser focus formed within the material, depending on the interaction of the laser and material parameters respectively.

[0149] The inventors have hitherto started from the fact that the energy deposited in the substrate can be regarded, on the one hand, as a result of the non-linear interaction between the electromagnetic field of the laser pulse and the substrate material, and on the other hand, as the cause of the modification within the substrate. Therefore, without considering a specific damage mechanism within the material, the deposited energy that can be simulated using a model suitable for non-linear laser pulse propagation can be used as a substitute for the manifestation of material modification.

[0150] For example, the critical strength for a glass substrate to cause a non-linear change in the material properties within the glass substrate, but in particular a plasma suitable for material processing, is at least 10 13 W / cm 2 . In one embodiment, the substrate material includes glass, and the electromagnetic field of the laser is at least 10 13 W / cm 2 , preferably at least 5×10 13 W / cm 2 , preferably at least 10 14 W / cm 2 , most preferably at least 5x10 14 W / cm 2 . Optionally, the electromagnetic field has a field strength of up to 10 16 W / cm 2 .

[0151] Possible structures for generating a curved linear focus by the method according to the invention can basically be configured as follows. That is, a laser beam from an ultrashort pulse laser is incident on a diffractive optical element (DOE), and the diffractive optical element (DOE) adapts the phase (laser pulse) of the incident laser beam by imposing a phase such as a cubic phase. Thereafter, the beam is focused onto the substrate body to be structured by a microscope objective lens and / or a Fourier lens. Depending on the phase distribution generated behind the DOE, the imaging objective lens generates not a straight focal line but rather a curved focal line. In one embodiment, the secondary maxima of the airy beam can also be suppressed. In this case, the intensity ratio of the main focus to the remaining part of the beam can be optimized (1.2 to 10). This can be achieved, for example, by non-radiative symmetric apodization on the Fourier plane using a diaphragm.

[0152] For example, the DOE used as a phase mask has a diameter of 5 to 15 mm, preferably 9 mm. In this case, the DOE is located at the "front focal plane" of the microscope objective lens or the Fourier lens. Preferably, the DOE (or generally speaking, the phase mask) has an operating distance from the associated lens that is equal to the focal length of the lens and / or is between 2 and 15 mm, preferably 5 mm. In the case of a microscope objective lens, if the "front focal plane" is within the objective lens itself, it is preferable in this case to select the (structurally defined) minimum distance.

[0153] For example, in this specification, an airy beam can be used. The airy beam is particularly well-suited for asymmetric / lateral beam guiding.

[0154] In addition, the airy beam can be generated particularly simply and efficiently. For example, the airy beam can be generated as the imaging of a beam having a cubic phase, which is directly generated by a phase mask (DOE or SLM) or by a structure with a cylindrical lens.

[0155] As the pulse energy (laser parameter Ep), a value of, for example, 300 μJ can be selected. As the number of pulses in a burst (laser parameter N), a value of, for example, 2 can be selected, and / or as the pulse duration (laser parameter τ), a value of, for example, 5 ps can be selected. Optionally, the focal length f of the optical system can be set to 10 mm, and / or a beam expander with a magnification of 2.0 (especially in the case of an input Gaussian beam with a diameter of 10 mm) can be provided.

[0156] By appropriately selecting the optical setup (especially the vertical distance between the focusing optical system and the substrate material to be processed, i.e., determining the focal position and focal length), such curved corrections can be formed internally or by penetrating one or both of the two large surfaces (the bottom surface and / or the outer surface) into the substrate material.

[0157] When the pulse energy is greater than the threshold value that depends on the material of the substrate, a non-linear interaction occurs between the laser and the material, which may lead to the aforementioned corrections. Therefore, in one embodiment, preferably, the pulse energy becomes greater than the threshold value that depends on the material of the substrate, thereby causing a non-linear interaction between the laser and the material.

[0158] Alternatively or additionally, the region to be corrected within the substrate is opened by the generation of mechanical and / or thermal stress and / or by an etching method, in particular for generating through-holes and / or blind holes within the substrate material, and / or the region to be corrected within the substrate is opened by mechanical, thermal, and / or chemical processes along a closed contour and / or along a correction extending from one side of the substrate to the other side of the substrate, in particular for generating an internal or external contour having a shaped side surface.

[0159] Alternatively or additionally, at least one auxiliary substrate is arranged on the substrate, at least during the control of the energy distribution, and the linear focus extends at least partially into the auxiliary substrate. In this case, preferably, two or more auxiliary substrates are arranged on the substrate, in particular on opposite sides of the substrate, and it may be assumed that the linear focus extends at least partially into two or more auxiliary substrates.

[0160] Preferably, the auxiliary substrate is made of the same material as the substrate.

[0161] By using such an auxiliary substrate, in the case of a penetrating linear focus, it becomes possible to avoid or at least significantly reduce the aberration portion or aberration effect on the exposed substrate surface.

[0162] For example, in one embodiment, the substrate to be structured can be processed together with an auxiliary substrate that has been subjected to drawing, adhesion, and / or ultrashort pulse welding, such that only internal effects are initially generated during the process, and these become exposed, so to speak, by removal of the auxiliary substrate in a further process step (which can also be described as peeling, for example).

[0163] Thus, by providing an auxiliary substrate, it becomes possible to also influence the substrate region near the surface, in particular to give a targeted and preset energy distribution and / or influence to the substrate. This is because, based on this auxiliary substrate, the linear focus can extend beyond the substrate without, or with only minor, impairment of the passage of the linear focus. This ensures that in the region near the surface of the substrate, the linear focus does not deviate from the desired shape, that the energy distribution can be set according to a preset, and / or that the substrate material can be spatially influenced according to a preset.

[0164] In particular, when the auxiliary substrate and the substrate are made of the same material, this ensures that there is a seamless and especially offset-free transition of the linear focus at the interface between them.

[0165] Subsequently, the auxiliary substrate can be removed from the substrate. This exposes the original substrate with the substrate material that may have been affected again.

[0166] In other words, by removing the auxiliary substrate again, it is possible to properly influence the substrate up to the outer surface of the substrate.

[0167] One or more auxiliary substrates can be provided.

[0168] The auxiliary substrate can surround the substrate so as to surround it, so to speak, by one or more sides.

[0169] The auxiliary substrate reliably avoids the deposition of the substrate material occurring in the edge region of the surface due to the aberration effect.

[0170] Alternatively or additionally, the linear focus, and preferably the modified material region of the substrate, is completely enclosed within the substrate, especially during at least the control of the energy distribution. In this case, preferably, the method involves the material being removed from the substrate, especially along the main extension direction of the linear focus within the substrate, region by region, such that the modified material enclosed within the substrate becomes at least partially and / or region by region accessible from the outside. In particular, it is further assumed that the removal of the material from the substrate is carried out using etching.

[0171] That is, by having the linear focus completely within the substrate, it becomes possible to reliably avoid the aberration part or the aberration effect from reaching the original surface of the substrate or the obtained surface.

[0172] That is, according to the proposed features, the deposition of energy and the influence on the substrate material are only carried out in the regions existing inside the substrate. That is, it is not accessible from the outside. Thereby, the course of the linear focus is not impaired or is not impaired much. Therefore, it is guaranteed that the linear focus does not deviate from the desired shape and / or the substrate material is spatially affected according to the preset.

[0173] Thereafter, the substrate material can be removed from the substrate, for example, until (or beyond) reaching the affected substrate material. For example, the corresponding etching process has proven to be advantageous for this purpose because it can be carried out accurately and efficiently. In this way, a new surface, for example, at least one new, at least temporary outer surface of the substrate can be formed. By removing the substrate material, the affected material region becomes accessible from the outside. Thereby, for example, it becomes possible to remove the affected substrate material later.

[0174] In this way, it becomes possible to achieve within the substrate a material region that has been defined under very high reliability and that reaches the surface of the finally processed substrate. Thereby, a clean surface can also be realized.

[0175] For example, removal of material from the substrate will change at least one, preferably both outer surfaces of the substrate. So to speak, here the transition of the outer surface may occur, for example, along the main extension direction of a line focus.

[0176] The main extension direction of the line focus can here extend, for example, perpendicular to the original and / or modified outer surface of the substrate.

[0177] Alternatively or additionally, controlling the energy distribution within the substrate may further include (i) the laser beam having spherical aberration, particularly in at least the region of the line focus, and / or (ii) the spherical aberration of the laser beam being set, particularly in at least the region of the line focus.

[0178] In this regard, it has surprisingly been recognized that by the laser beam having spherical aberration, a more uniform and more extended energy distribution can be introduced into the substrate compared to the original airy beam. Thereby, better manifestation of the modified region within the substrate can be achieved. Thus, undesired damage to the substrate material can be reduced or even completely avoided, and / or the energy of the laser pulses can be reduced for a preset target energy distribution and target modification with respect to manifestation.

[0179] Furthermore, preferably, by setting the spherical aberration, it is possible to set the position of the maximum intensity of the energy distribution along a preferably positionally fixed line focus trajectory, and / or by changing the spherical aberration, it is possible to adapt, particularly shift, the position of the maximum intensity of the energy distribution along a preferably positionally fixed line focus trajectory.

[0180] This enables, in particular preferably along the trajectory of the linear focus, the achievement of a homogenization of the intensity, at least per region and / or per section, and moreover, in particular, does not change the trajectory of the linear focus, in particular its main maximum.

[0181] The spherical aberration preferably has a unit of 12.5 / f 3 where f is the focal length of the imaging system.

[0182] In the present application, when referring to the laser beam having spherical aberration, it is preferably understood to mean that the light beam of the laser beam does not converge at a specific point and / or that there is one or more rotationally symmetric phases of even order > 2, for example, the presence of a quartic additional phase term leading to a change in the effective focal length along the radius of the optical system.

[0183] Advantageously, the spherical aberration of the beam may be introduced using an optical system comprising a lens having spherical aberration whose phase satisfies the following formula φ lens (ρ)=k0*((ρ 2 / 2f)+aρ 4 ) where ρ is the radial distance from the optical axis.

[0184] Alternatively or additionally, the laser beam preferably propagates through an optical element having spherical aberration outside and / or in front of the substrate, whereby it is preferably assumed that the spherical aberration of the laser beam is at least partially set, in particular in the region of at least the linear focus.

[0185] This is a particularly simple and efficient means for setting and controlling the spherical aberration of the laser beam.

[0186] Alternatively or additionally, the quartic spherical aberration may be assumed to have an intensity of 0.02 / (f*w0^2) or more, where f is the focal length of the imaging system and w0 is the diameter of the laser beam.

[0187] This is particularly advantageous for a typical energy distribution for introducing corrections into a glass substrate.

[0188] Alternatively or additionally, due to spherical aberration, an extension of the focus formed within the substrate is achieved to be 5% or more, preferably 10% or more, preferably 15% or more, preferably 20% or more, preferably 25% or more, preferably 30% or more, preferably 35% or more, preferably 40% or more, preferably 50% or more, preferably 60% or more, and / or 100% or less, preferably 70% or less, preferably 50% or less, preferably 30% or less, where preferably, the focal length is such that the linear focus is assumed to be present along a section of the laser beam trajectory having an intensity of 75% or more, 80% or more, 85% or more, or 90% or more of the maximum intensity of the linear focus.

[0189] For this purpose, for example, it is possible to compare the length of the focus (i.e., the linear focus) formed within the substrate with and without the presence of set and / or controlled spherical aberration.

[0190] Alternatively or additionally, due to spherical aberration, an extension of the modified substrate material is achieved to be 5% or more, preferably 10% or more, preferably 15% or more, preferably 20% or more, preferably 25% or more, preferably 30% or more, preferably 35% or more, preferably 40% or more, preferably 50% or more, preferably 60% or more, and / or 100% or less, preferably 70% or less, preferably 50% or less, preferably 30% or less, where preferably, along the length, there is assumed to be a modification intensity having an intensity of 75% or more, 80% or more, 85% or more, or 90% or more of the maximum intensity of the modification.

[0191] Therefore, the difference can also be determined directly in the processed substrate.

[0192] Alternatively or additionally, it is assumed that the spherical aberration of the laser beam may vary with time, particularly in the region of the line focus, and in particular due to the temporal variation of the point of incidence of the laser beam on the phase mask and / or on an optical element such as the microscope objective of the optical structure.

[0193] Thereby, a temporal depth variation of the material modification can be achieved particularly easily. For example, the material modification can be formed "from bottom to top" by changing the spherical aberration, whereby the line focus and the associated energy distribution are extended as a function of time and / or the maximum of its intensity is shifted.

[0194] Alternatively or additionally, the central point of the laser beam incident on the optical element is incident on the optical element, at least temporarily, with an offset with respect to the optical axis of the optical element, where preferably the offset may be assumed to vary with time.

[0195] This may be realized particularly simply, for example, by moving the laser beam and / or the optical element relative to each other.

[0196] Alternatively or additionally, a constant offset and / or a maximum offset may be assumed to be set between 20 mm or less, preferably 15 mm or less, preferably 10 mm or less, preferably 5 mm or less, preferably 3 mm or less, preferably 2.5 mm or less, preferably 2 mm or less, preferably 1.5 mm or less, preferably 1 mm or less, 0.001 mm or more, preferably 0.003 mm or more, preferably 0.01 mm or more, preferably 0.1 mm or more, preferably 1 mm or more, preferably 5 mm or more, preferably 10 mm or more, preferably 15 mm or more, and / or between 0.001 mm and 20 mm, preferably between 0.001 mm and 10 mm, preferably between 0.003 mm and 10 mm, preferably between 0.003 mm and 5 mm, preferably between 0.003 mm and 2 mm, preferably between 0.003 mm and 1.5 mm.

[0197] Alternatively or additionally, it may be assumed that the optical element is a lens, and the lens preferably has a spherical curvature at least for each region.

[0198] This is a particularly simple and suitable means for controlling the laser beam to introduce spherical aberration.

[0199] Alternatively or additionally, it may be assumed that the spherical aberration is a spherical aberration of the fourth or higher order.

[0200] As a result, particularly good results were achieved.

[0201] Alternatively or additionally, when the integer k > 2, it may be assumed that the spherical aberration is a spherical aberration by a Zernike polynomial having the exponents m = 0 and n = 2k.

[0202] As a result, particularly good results were achieved.

[0203] Alternatively or additionally, it may be assumed that the spherical aberration and the influence of the laser beam using the phase mask are sequentially adjusted by sequentially adjusting, in particular preferably varying with time, the incident point of the laser beam on the optical element and, preferably varying with time, the incident point of the laser beam on the phase mask.

[0204] By the interaction of two independent mechanisms, particularly good control of the energy distribution introduced into the substrate can be achieved.

[0205] Alternatively or additionally, by setting the spherical aberration, it may be assumed that the energy distribution, intensity, and / or intensity distribution of the rear end section of the linear focus along the main extension direction of the linear focus can be set, particularly changed such as enlarged.

[0206] Here, the effect that spherical aberration is associated with an asymmetric influence on the linear focus and the energy distribution (in particular, manifesting only on one side of the original focus) is advantageously utilized. Therefore, by arranging the amplified region behind the linear focus, this effect can be utilized to compensate for a suitable energy deposition based on the non-linear effect in front of the linear focus.

[0207] Alternatively or additionally, it may be assumed that the positioning of the energy distribution along the linear focus, in particular along the trajectory of the linearly focused position-fixed preferably, can be changed and / or set by the setting of spherical aberration.

[0208] Alternatively or additionally, the step of controlling the energy distribution in the substrate further includes that the wavelength of the laser beam is changed depending on time, in particular continuously or discretely, preferably in the optical path of the laser beam, preferably in front of the substrate, and it may be assumed that an optical element for refracting the laser beam depending on the wavelength is provided.

[0209] The optical element may be, for example, a prism preferably arranged in the optical path of the laser beam.

[0210] Alternatively or additionally, the laser beam has an elongated, in particular rectangular or oval, for example elliptical beam cross-section at least for each section, in particular in the plane of the phase mask, at least intermittently, where preferably the beam cross-section is assumed to change over time, in particular between circular and oval.

[0211] By using a rectangular beam cross-section, in particular, a constant intensity distribution can be achieved along the propagation.

[0212] Surprisingly, it has been recognized that a laser beam having a cross-section deviating from a circular surface (especially on a phase mask) can have a linear focus with reduced secondary maxima. This makes it possible to avoid or at least reduce unwanted modifications in the substrate caused by the secondary maxima.

[0213] Preferably, the laser beam is here an elliptical beam. The elliptical beam is preferably characterized in that the beam diameters along two mutually perpendicular main axes are offset from each other. The elliptical beam can be generated by adapting the beam diameter of a rotationally symmetric beam in the spatial direction by means of a corresponding optical system, for example a telescopic optical system consisting of cylindrical lenses, in particular by enlarging or reducing it.

[0214] By using the proposed formation of the laser cross-section, the contrast of the linear focus can be increased. This is because the intensity of the primary maximum can be increased compared to the intensities of the respective secondary maxima. Additionally, the orientation of the secondary maxima is observed, where the secondary maxima extend as parallel as possible to the planned separation plane. Thereby, the secondary maxima do not affect or only minimally affect the introduction of modifications in the substrate.

[0215] Additionally, by using the proposed formation of the laser cross-section, secondary maxima of a somewhat blurred linear focus can be achieved, whereby adjacent secondary maxima shift into each other. Thereby, a particularly good quality of the cut surface can be achieved.

[0216] In combination with the proposed formation of the laser cross-section, advantageously, the orientation of the cracks in the substrate can be achieved, which extend substantially along the modifications generated by the primary maximum of the linear focus in the substrate during or for the formation of the separation plane or during or for the splitting of the substrate. Alternatively or additionally, the cracks are collinear with respect to the desired cut. Thereby, a particularly good quality can be achieved at each cut surface.

[0217] Advantageously, here, in particular in a cross-section perpendicular or parallel to the outer surface of the substrate, the material modification caused by the secondary maximum of the line focus extends substantially parallel and / or linearly with respect to the planned cutting plane. This can be achieved, for example, by appropriately orienting the substrate and the laser beam (in particular with an elongated beam cross-section) relative to each other.

[0218] Advantageously, here, the material modifications caused by the secondary maximum of the line focus are arranged onion-skin-like within the substrate material.

[0219] Alternatively or additionally, a plurality of material modifications are introduced into the substrate, and the distance between adjacent material modifications, in particular the distance between the centers of gravity of the material modifications, and / or the distance in a cross-section parallel to the outer surface of the substrate is assumed to be 1 μm or more, preferably 3 μm or more, preferably 5 μm or more, preferably 7 μm or more, preferably 10 μm or more, preferably 15 μm or more, preferably 20 μm or more.

[0220] Particularly in combination with a laser beam having a cross-section deviating from a circular surface, surprisingly, even though the distance between adjacent modifications (so-called "pitch") is relatively large, for example, not only 1 μm or more but preferably 10 μm or more, 20 μm or more, 30 μm or more, 40 μm or 50 μm or more, a particularly reliable separation surface can be achieved. In the case of such relatively long distances, it is possible to avoid or at least reduce the influence of the line focus, in particular by shifting the time or by adjacent modifications introduced simultaneously.

[0221] That is, as a result, with the proposed distance, it is possible to avoid or at least reduce the interaction between adjacent regions within the substrate with modifications.

[0222] In particular, the modified outliers that are angled laterally / manifested in an arrow shape (especially caused by the secondary maximum of the linear focus) generally overlap only within a reduced range or not at all, depending on the corresponding distance.

[0223] By selecting an elongated beam cross-section, these outliers can be reduced once again, so that reliable material corrections can be made at multiple locations in line with increasing the spacing between adjacent pitches. Thereby, it can be ensured that the propagation of the laser beam within the material is not inhibited or only very slightly inhibited by previous corrections and / or adjacent corrections.

[0224] This problem is solved by proposing a substrate according to a second aspect of the present invention, the substrate comprising at least one first outer surface, preferably at least one second outer surface extending parallel to the first outer surface, and preferably at least one side surface extending at least region by region between the first outer surface and the second outer surface, in particular a laser-damaged side surface, wherein in a cross-section of the substrate extended by a plane having at least one normal vector of the side surface and a normal vector of the first outer surface, the contour of the side surface has a vertex disposed between the two outer surfaces, where preferably (i) the vertex is (a) disposed in the center between the two outer surfaces and / or (b) disposed with a particular vertical distance from the central position between the two outer surfaces, in particular the vertical distance along a direction parallel to the normal vector of the first outer surface is (aa) more than 0.1% of the thickness of the substrate, preferably more than 1%, preferably more than 5%, preferably more than 10%, preferably more than 20%, preferably more than 30%, preferably more than 40%, preferably more than 45%, and / or (bb) less than 50% of the thickness of the substrate, preferably less than 45%, preferably less than 35%, preferably less than 25%, preferably less than 15%, preferably less than 10%, preferably less than 5%, preferably less than 3%, preferably less than 1%, and / or (cc) between 0.1% and 49% of the thickness of the substrate, preferably between 0.1% and 10% or between 1% and 40%, preferably between 5% and 30%, preferably between 10% and 25%, (ii) the side surface is height-corrected at least region by region, in particular preferably having a wavy and / or domed structure along and / or perpendicular to the main extension direction of the side surface, and / or (iii) the substrate has a curved correction having a course according to at least one section of the trajectory of the air beam.

[0225] Height correction has proven to be advantageous because it contributes to an increase in the strength of the surface.

[0226] The contour of the side surface is here preferably to be understood as meaning the particularly straight course of the side surface in the cross-section.

[0227] This problem is solved by proposing a substrate according to a third aspect of the present invention, the substrate comprising at least one first outer surface, preferably at least one second outer surface extending parallel to the first outer surface, and preferably at least one laser-damaged side surface extending at least region by region between the first outer surface and the second outer surface, wherein in a cross-section of the substrate extended by a plane having at least one normal vector of the side surface and a normal vector of the first outer surface, the contour of the side surface has a vertex disposed between the two outer surfaces, the vertex being disposed at the center between the two outer surfaces and / or being disposed with a distance, particularly in the vertical direction, from the central position between the two outer surfaces, wherein the vertical distance along a direction parallel to the normal vector of the first outer surface is (i) more than 0.1%, preferably more than 1%, preferably more than 5%, preferably more than 10%, preferably more than 20%, preferably more than 30%, preferably more than 40%, preferably more than 45% of the thickness of the substrate and / or (ii) less than 50%, preferably less than 45%, preferably less than 35%, preferably less than 25%, preferably less than 15%, preferably less than 10%, preferably less than 5%, preferably less than 3%, preferably less than 1% of the thickness of the substrate and / or (iii) between 0.1% and 49%, preferably between 0.1% and 10% or between 1% and 40%, preferably between 5% and 30%, preferably between 10% and 25% of the thickness of the substrate, wherein the thickness of the substrate is more than 500 μm, preferably more than 700 μm, preferably more than 1000 μm, preferably more than 1500 μm, preferably more than 2000 μm. In particular, it is proposed that the thickness of the substrate can be less than 10 cm, preferably less than 7 cm, preferably less than 5 cm, preferably less than 3 cm.

[0228] In the case of the first, second, and / or third aspect of the present invention, alternatively or additionally, the following, namely, (i) The substrate is transparent and made of glass and / or glass ceramic, has a first outer surface, and / or preferably has a second outer surface extending parallel to the first outer surface and / or present on the opposite side of the first outer surface, and / or (ii) The substrate preferably has a thickness measured between a first outer surface and a second outer surface, and this thickness is (a) 10 μm or more, preferably 30 μm or more, preferably 50 μm or more, preferably 70 μm or more, preferably 100 μm or more, preferably 300 μm or more, preferably 500 μm or more, preferably 700 μm or more, preferably 1 mm or more, preferably 3 mm or more, preferably 5 mm or more, preferably 7 mm or more, preferably 10 mm or more, and / or (b) 10 mm or less, preferably 7 mm or less, preferably 5 mm or less, preferably 3 mm or less, preferably 1 mm or less, preferably 700 μm or less, preferably 500 μm or less, preferably 300 μm or less, preferably 300 μm or less, preferably 200 μm or less, preferably 100 μm or less, preferably 70 μm or less, preferably 50 μm or less, preferably 30 μm or less, preferably 10 μm or less, and / or (c) It may be assumed to be between 10 μm and 10 mm, preferably between 10 μm and 500 μm, preferably between 50 μm and 200 μm.

[0229] Further features and advantages of the present invention will become apparent from the following description in which preferred embodiments of the invention are described based on schematic diagrams.

Brief Description of the Drawings

[0230]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9a

Figure 9b

Figure 9c

Figure 9d

Figure 10a

Figure 10b

Figure 10c

Figure 11

Figure 12

Figure 13a

Figure 13b

Figure 13c

Figure 14a

Figure 14b

Best Mode for Carrying Out the Invention

[0231] FIG. 1 shows an optical structure 1 for implementing a method according to a first aspect of the present invention.

[0232] The optical structure 1 includes a pulsed laser (not shown) that emits a laser beam 3 having a wavelength of 1030 nm. The laser beam 3 has a diameter of 2ω0. This optical structure further includes a cubic phase mask 5 and a focusing optical system 7 that is disposed at a distance D from the phase mask and has a focal length f of, for example, 10 mm. The phase mask 5 and the focusing optical system 7 generate an airy beam having a curved linear focus from the laser beam 3. For this purpose, the laser beam 3 passes through the phase mask 5 and then through the focusing optical system 7.

[0233] The substrate 9 to be separated along the planned separation plane is arranged at a distance d from the focusing optical system 7 such that a curved linear focus of the laser beam 3 is formed within the substrate. The distance d is here defined with respect to the outer surface of the substrate 9 facing the laser source. The distance Δz1 between the apex of the linear focus and the outer surface of the substrate 9 facing the laser source, and thus the relative vertical position of the linear focus within the substrate 9, are also set herein by the choice of the focal length f and / or by the choice of the distance d between the substrate 9 and the focusing optical system 7. An increase in the focal length f or a decrease in the distance d shifts the apex of the linear focus, and thus the apex of the entire curved linear focus, away from the outer surface of the substrate 9 facing the laser source, i.e., downward in FIG. 1. Correspondingly and conversely, a decrease in the focal length f or an increase in the distance d shifts the apex of the linear focus toward the outer surface of the substrate 9 facing the laser source, i.e., upward in FIG. 1. In other words, the curved linear focus can be moved along the depth region passing through the substrate 9 by a change in the distance d between the focusing optical system 7 and the outer surface of the substrate 9 facing the laser source and / or by a change in the focal length f of the focusing optical system 7. Thereby, the apex of the linear focus can be positioned, for example, centrally within the substrate 9 with high reliability, but can also be offset with respect to the substrate 9 and positioned at any location across the thickness of the substrate 9, i.e., shifted, for example, toward the first outer surface. Of course, it is also possible to adapt the focal length f and the distance d simultaneously, for example, in such a way that the focal length f is decreased and the distance d is increased, in order to adapt the position of the apex.

[0234] When the linear focus has, for example, an axis of symmetry, symmetric and asymmetric material modifications can be generated within its volume across the thickness of the substrate 9, depending in particular on the position of the apex within the substrate 9 selected by the setting of the focal length f and / or the distance d. Thus, in particular, it becomes possible to generate symmetric modifications, for example, present in the center of the substrate, whereby the material modification is formed, for example, in a C-shape. In contrast, when the linear focus does not have an axis of symmetry, it becomes possible to generate asymmetric material modifications along the thickness of the substrate 9.

[0235] In this case, both symmetric and asymmetric linear foci preferably result in advantageous material modifications within their volume over the thickness of the substrate 9, and particularly in the region where the linear focus is formed.

[0236] Thus, in addition to the curved linear foci generated in this way, particularly at asymmetric positions eccentric with respect to the outer surface of their apexes, preferably, by appropriate selection of the focal length f, and thus also with respect to the substrate thickness, positioning of a central and thus symmetric curved linear focus can also be achieved within the substrate 9.

[0237] FIG. 2 shows a cubic phase mask that can be used for the phase mask 5.

[0238] FIG. 3 shows a cross-sectional view of a substrate 11 having a substrate region 13 whose refractive index is modified by a curved linear focus of an airy beam.

[0239] Specifically, for this purpose, a pulse having a pulse energy of 342 μJ was used, and as described with respect to FIG. 1, an airy linear focus was formed within the substrate 11, i.e., within the borofloat 33. The laser beam had a main propagation direction R here.

[0240] To modify the material, the material was modified along the section of the linear focus where a sufficiently high energy density was introduced into the substrate throughout. The circular surfaces at two external positions of the modification 13 characterize the experimental detection limit of the modification 13. The two external positions have a distance of Δz2 along the depth region of the substrate 11, i.e., along the thickness of the substrate 11.

[0241] In addition, the location where the maximum value of the energy distribution introduced by the linear focus exists, and thus where the maximum modification of the substrate material occurs, is also characterized by a square in FIG. 3. The apex of the curved region is characterized by a triangle. Here, it is shown that the apex and the location of the maximum modification do not coincide.

[0242] Figure 4 shows the simulated evolution of the linear energy density along the linear focus in the substrate for different pulse energies. Therefore, the effect of the pulse energy on the energy distribution in the substrate can be at least qualitatively described.

[0243] Therefore, in Figure 4, the location of the maximum linear energy density along the focus of the airy beam (simulated here) can be read, which coincides with the position of the apex of the 2.5 mm focal trajectory in the substrate in the absence of pulse energy. The maximum modification in the substrate preferably occurs at the location of the maximum value of the energy distribution in the substrate.

[0244] As can be read from the drawing of Figure 4, for a pulse energy of 76 μJ (the bottom curve in the drawing), the linear energy density has a maximum value of about 12 μJ / mm at a depth of about 2.4 mm. For a pulse energy of 342 μJ (the top curve in the drawing), the linear energy density has a maximum value of about 118 μJ / mm at a depth of about 2.1 mm. The maximum values of the linear energy density are each characterized by a square according to Figure 3. Therefore, as the pulse energy increases, the maximum value of the linear energy density also increases. Additionally, the position of the maximum value shifts in the direction of shallower depth as the pulse energy increases. In this case, here, a depth of 0 mm is with respect to the substrate surface, that is, with respect to the side of the substrate facing the laser source.

[0245] Additionally, each is characterized by two circular surfaces, and for each pulse energy, the depth region in which modification will occur in a typical glass material can be read out. The modification occurs along a depth region Δz of about 0.3 mm for a pulse energy of 76 μJ and along a depth region Δz of about 2 mm for a pulse energy of 342 μJ. The length of the linear focus that generates the modification between the two end points is here longer than the distance Δz between two points in the depth direction based on its curvature.

[0246] As the pulse energy increases, the modification becomes increasingly asymmetrically manifested, and it can be determined that the location of the maximum damage increasingly moves away from the apex of the airy trajectory at 2.5 mm towards shallower depths.

[0247] Therefore, Figure 4 depicts how the energy distribution introduced into the substrate material by the linear focus can be controlled by setting the pulse energy. That is, for example, in the form of the maximum linear energy density, but also in the form of the length of the section of the linear focus along which the substrate material is modified in the depth section Δz.

[0248] Regarding Figure 4, the linear energy density was mentioned. This linear energy density here relates to the energy density along the focal trajectory of the airy beam. Those skilled in the art will understand that this description is useful for better understanding how a particular setting of the pulse energy affects the (spatial) energy distribution within the substrate. Because the actual energy distribution within the substrate that generates the modification is basically determined by the linear energy density of the focus discussed here, but additional aspects may also similarly affect the energy distribution within the substrate. For example, based on absorption by plasma, also known as plasma shielding, generated in the material, for example, and focal blur, an upper limit value for the maximum value of the energy density within the substrate may be given, and this upper limit value cannot be exceeded even by increasing the linear energy density of the focus. This effect is also referred to as intensity clamping.

[0249] Figure 5 shows the progression of the depth position of the maximum value of the material modification determined experimentally for different pulse energies.

[0250] For this purpose, a plurality of corrections are introduced into the substrate, where different pulse energies are set for each correction. Thereafter, for each correction, the position of the maximum value of the correction is determined, where it can be accepted that this is also the position of the maximum value of the linear energy density. For all corrections, the apex of the associated linear focus was set at the same depth.

[0251] Here too, when comparing two positions, a relative description is possible, in particular. The greater the pulse energy, the correspondingly the depth of the maximum value changes (towards a shallower depth), and in this case, the progression is approximately linear.

[0252] FIG. 6 shows the influence of the offset of the laser beam on the cubic phase mask on the position of the maximum value of the focal intensity, and thus also shows the effective influence on the energy distribution in the substrate along the focal trajectory.

[0253] That is, in this specification, it was investigated using a simulation of the offset effect between the input beam and the cubic phase mask on the relative positioning of the maximum value of the energy distribution and the apex of the airy trajectory.

[0254] When the input beam is centered, for the sake of explanation, it is determined that the position of the apex coincides with the maximum value of the energy distribution. (In reality, this would correspond to the case where the linear focus and the energy distribution are observed in a vacuum). Of course, this is not the case when the linear focus is formed in the substrate material, but rather there may be a shift between the location of the apex and the location of the maximum value. The greater the offset (characterized by dx in the left part of FIG. 6) of the input beam (characterized by the ○ mark) within the horizontal symmetry plane (mirror plane) of the phase distribution, the more the location of the maximum value of the energy distribution is shifted relative to the apex of the airy trajectory.

[0255] In the right part of FIG. 6, when the offset changes from -0.5 mm to 0.5 mm, how the energy distribution 15 along the airy linear focusing orbit 17 shifts from top to bottom in FIG. 6 is shown.

[0256] FIG. 7 shows the course of the dependence between the offset dx of the laser beam from the saddle point of the cubic phase mask and the position of the maximum value of the linear energy density along the focal orbit.

[0257] Here, the average value of the Z position (i.e., the depth position) of the relevant material modification endpoints (characterized, for example, by the circular surface in FIG. 3) was used as the experimental position.

[0258] The gradient of the goodness of fit (the "goodness of fit" shown by the solid line in FIG. 7) in the experimental data ("data") is 0.065. That is, this means that for the focusing underlying the data, a focal offset of 65 μm is achieved in the z direction (in air) for every 1 mm shift of the beam on the cubic phase mask.

[0259] In FIG. 7, the course that should be theoretically estimated is further shown by the dotted line. The theoretical course for the offset dx is given by the following equation shown here again

Equation

[0260] 1 again, it is shown that in this embodiment, the laser beam 3 is influenced by the phase mask 5, for example by shifting the phase mask 5 relative to the laser beam 3 and by setting the pulse energy of the laser beam 3, so that the energy distribution introduced by the line focus into the substrate can be reliably controlled. Modifications can therefore be reliably and symmetrically produced in the substrate 9.

[0261] In particular, by selecting the mutually coordinated pulse energies and by the influence of the laser beam by the phase mask (e.g. by selecting the offset of the laser beam from the saddle point of the phase mask), the position of the maximum of the energy distribution in the substrate (characterized by Δz1 in the enlarged portion of FIG. 1) can be reliably controlled.

[0262] Effect of focal length of focusing optical system Figure 8 illustrates the effect of the focal length of a focusing optics on an Airy laser beam. For the constants: -Cubic phase (β=3 1 / 3 x10 3 / m); -Laser wavelength (where λ=1.030x10 -6 m); -Beam diameter (raw beam diameter w0=5x10 -3 m); The length of the focal region increases with increasing focal length (relatively defined as 1 / e 2 to 0° (solid curve in FIG. 9), the angles that the focal points at the upper and lower ends respectively have with the optical axis decrease (dashed curve in FIG. 9). Thus, the left vertical axis relates to the solid line and the right vertical axis relates to the dashed line.

[0263] Example of generating beam offsets Figures 9a to 9c show various means for generating an offset of the laser beam on the phase mask. Here, it can be considered that the saddle point of the phase function on each phase mask, and thus the center point, exists at the geometric center point of each phase mask.

[0264] Figure 9a shows an optical structure 1' similar to the optical structure 1 shown in FIG. 1. Therefore, the same features are also assigned reference numerals that are the same but with a single prime symbol added.

[0265] In Figure 9a, the optical system is characterized by reference numeral 19', and its optical axis is characterized by reference numeral 21'. The optical system 19' includes a deflection optical system 23' in addition to the phase mask 5' and the focusing optical system 7'.

[0266] By this deflection optical system 23', the laser beam 3' is deflected, whereby the laser beam 3' extends obliquely with respect to the optical axis 21'. This can be well recognized from the central axis 25' of the beam 3', which extends obliquely (and is no longer parallel to the optical axis 21') behind the deflection optical system 23'.

[0267] Based on the deflection, the laser beam 3' is incident on the phase mask 5' with an offset 27'. Therefore, the incident point of the laser beam 3' on the phase mask 5' (more appropriately, the location of the centroid of the beam cross-section in the plane of the phase mask 5') has a lateral offset 27' with respect to the center point 29' of the phase mask 5'.

[0268] Figure 9b shows an optical structure 1'' similar to the optical structure 1' shown in FIG. 9a. Therefore, the same features are also assigned reference numerals that are the same but with a double prime symbol added.

[0269] However, the optical system 19’’ may not include the deflection optical system 23’’ or (as shown in Fig. 9b) the deflection optical system 23’’ has no effect, so the beam 3’’ is not deflected. However, the phase mask 5’’ is shifted in a direction perpendicular to the beam direction, so that the laser beam 3’’ is incident on the phase mask 5’’ with an offset 27’’.

[0270] Fig. 9c shows an optical structure 1’’’ similar to the optical structure 1’ shown in Fig. 9a and the optical structure 1’’ shown in Fig. 9b. Therefore, the same features are labeled with reference numerals that are the same but with triple prime symbols added.

[0271] The optical system 19’’’ includes a deflection optical system 23’’’ that generates an offset 27’’’ of the laser beam 3’’’ so that it can be well recognized by comparing the passage of the central axis 25’’’ of the laser beam 3’’’ before and after the deflection optical system 23’’’.

[0272] As a result, the laser beam 3’’’ is incident on the phase mask 5’’’ with an offset 27’’’. However, at this time, the center point 29’’’ of the phase mask 5’’’ is on the optical axis 21’’’ (as in the case of the optical structure 1’ in Fig. 9a).

[0273] Fig. 9d shows an embodiment of the deflection optical system 23’’’. This deflection optical system 23’’’ can include a rotating plate 31’’’. This rotating plate 31’’’ generates an offset 27’’’.

[0274] Phase correlation function Various exemplary phase functions that can be imposed on the laser beam and can be used as a phase mask for the method according to the invention are shown in the following table:

Table 1

[0275] These parameters are described in the publication "Froehly, L., Courvoisier, F., Mathis, A., Jacquot, M., Furfaro, L., Giust, R., & Dudley, J. M. (2011). Arbitrary accelerating micron-scale caustic beams in two and three dimensions. Optics express, 19(17), 16455-16465".

[0276] Preferably, the optical structure for generating the above phase function is an optical structure having a telescopic structure for focusing a laser beam.

[0277] Further embodiments FIG. 10a shows a rectangular substrate 33 in cross-section. Inside the substrate 33, the substrate material is modified within the region 35, particularly by the interaction between the energy and the substrate material, based on the energy deposited using a linear focus within the substrate 33.

[0278] The curved region 35 is completely enclosed within the substrate 33.

[0279] Therefore, according to the present invention, in an embodiment, it is envisioned that the material is removed from the substrate 33, for example, using etching. This can be done along the main extension direction H of the curved region 35 (or the corresponding linear focus of the process), which, in this specification, extends perpendicular to the two outer surfaces 37. In other words, in this regard, the material is removed from the two outer surfaces 37 of the substrate 33. This causes the new outer surfaces 37 of the substrate 33 to shift, so to speak, along the main extension direction H. This can be recognized in FIG. 10b. Additionally, it can be recognized there that the substrate material 35 affected within the enclosed curved region 35 becomes accessible from the outside due to the removal of the substrate material. This is because a part of the affected substrate material comes to be present on the surface of the outer surface 37 here.

[0280] The curved region 35 has a course that is not affected by surface effects (e.g., the outer surface 37). This is because the interaction occurs completely within the substrate 33 (Figure 10a).

[0281] Due to the accessibility of the modified substrate material 35 (Figure 10b), the substrate can then be subsequently processed as depicted in Figure 10c. For example, for this purpose, the affected material is removed by etching and the substrate is divided.

[0282] Further aspects Figure 11 shows a plan view of a substrate processed by the method according to the invention. In particular, the normal vector of the formed surface (i.e., the curved separation surface) extends within the drawing plane of Figure 11. Therefore, in Figure 11, the curved course of the separation surface can also be recognized particularly advantageously.

[0283] In particular, here the symmetric course of the curved separation surface can be recognized.

[0284] Here, the laser beam used extended parallel to the drawing plane of Figure 11, as indicated by the arrow.

[0285] For the laser processing, the following general parameters and laser parameters were set: - A substrate material having a thickness selected from the region between 900 and 1000 μm, for example BF33; - A pitch of 40 μm; - A microscope objective lens and / or a Fourier lens having a focal length f = 10 mm; - A beam expander of x2.0 (in the case of a Gaussian input beam with a diameter of 10 mm); - A pulse duration τ = 5 ps; - The number of pulses within a burst of N = 2; - An energy of 300 μJ per burst; - A wavelength of 1030 nm; - A cubic phase φ = exp(i*(x 3 +y 3))、 φ = exp(iβ / 3 * (x 3 + y 3 )) is equivalent, provided that β = 3 1 / 3 mm -1 , and x and y are in mm units; In this way, by selecting a sufficiently large pitch, the interaction between adjacent regions within the substrate with modifications is avoided or at least significantly reduced.

[0286] On the left side of FIG. 12, a plan view of the substrate in a transmission light microscope is shown, specifically the state after the laser process but before etching (this perspective is parallel to the laser propagation direction here). Here, the lateral manifestation of the modification can be seen, and in this case, multiple modifications can be seen for three different selected depths within the substrate, respectively. Each depth is marked in the right part of FIG. 12.

[0287] When introducing the modification, a sufficiently large pitch is selected, whereby the outliers of the modification manifested laterally / arrow-shaped overlap only minimally. Thereby, it is ensured that the propagation within the material is not inhibited or only very slightly inhibited by the previous modification.

[0288] That is, the "zigzag" pattern results from the modification expanded laterally near the focus, while the modification continues to exist linearly / on the line. Additionally, the apex of the curved linear focus is preferably held at the center between the two outer surfaces, and the linear focus is completely formed within the substrate material.

[0289] Supplementary aspect FIG. 13a shows an optical structure 1 iv that can control spherical aberration and advantageously can also control the inclination of the modification within the substrate. iv This optical structure 1

[0290] Beam focusing optical system 7 iv is an imaging optical system having spherical aberration in this specification. When a laser beam passes through this beam focusing optical system 7 iv the laser beam receives spherical aberration particularly preferably depending on the incidence point to the beam focusing optical system 7 iv .

[0291] Beam focusing optical system 7 iv may include a lens having spherical aberration whose phases satisfy the following formula φ lens (ρ) = k0 * ((ρ 2 / 2f) + aρ 4 ) .

[0292] Deflection optical system 23 iv is deactivated in this case, so the beam 3 iv is not deflected. When it is activated, the incidence point of the laser beam 3 iv on the beam focusing optical system 7 iv can be adapted (also) using the deflection optical system 23 iv , and thus the spherical aberration of the laser beam 3 iv and / or the inclination of the correction introduced into the substrate can also be changed.

[0293] However, the deflection optical system 23 iv is deactivated in this case and thus has no effect, so the beam 3 iv is not deflected. However, since the beam focusing optical system 7 iv is shifted in a direction perpendicular to the beam direction, the laser beam 3 iv is incident on the beam focusing optical system 7 iv with an offset 27 iv with respect to the center point 39 iv of the beam focusing optical system 7 iv .

[0294] Due to the offset 27 iv the laser beam receives the adapted spherical aberration, and therefore the substrate 9 ivThe energy distribution introduced therein can be changed and / or shifted along the linear focus 17 iv and becomes changeable and / or shiftable.

[0295] Figure 13b shows the intensity profile of the laser beam along the depth direction of the substrate for differently set spherical aberrations. For this purpose, for example, in the optical structure 1 iv the offset 27 iv may be changed respectively so that the linear focus formed in the substrate 9 iv has different energy distributions.

[0296] As the spherical aberration increases, the rear section of the linear focus (i.e., the section towards the deeper depth z direction in the substrate) may be amplified in intensity. Thereby, the correction can be better formed along the entire depth region and / or using a reduced laser output within the substrate material.

[0297] Figure 13c shows three substrates with corrections introduced under differently set spherical aberrations and offsets of the input beam (shown on the left, in the center, and on the right in the figure).

[0298] Here, each spherical aberration was set by a different offset of the laser beam and the focusing optics of the optical system used for this purpose (see offset 27 described in relation to Figure 13a).

[0299] In the correction of the substrate shown on the left in Figure 13c, an offset of 0 mm was set, so there is no offset. In the correction of the substrate shown in the center of Figure 13c, an offset of 0.7 mm was set. In the correction of the substrate shown on the right in Figure 13c, an offset of 1.4 mm was set.

[0300] The three substrates shown in FIG. 13c all have the same thickness and are shown arranged flush with their upper surfaces. Therefore, it can be seen from FIG. 13c that as the offset increases, the modification becomes longer and becomes more prominent even at greater depths (in FIG. 13c, the deeper they are along the vertical axis, the more prominent they become). The reason for this is that when spherical aberration increases as shown in the figure, the energy distribution along the linear focus trajectory is also introduced into the substrate material in a more prominent and rearward direction over a longer length and is controlled there.

[0301] Further advantageous features for dynamic effects Regarding dynamic effects, particularly advantageously, the phase mask and / or DOE, in particular the point of incidence of the laser beam on the phase mask, the focal length, in particular the focal length of the microscope objective of the optical structure, the spherical aberration of the laser beam, in particular the point of incidence of the laser beam on the lens, and / or the pulse energy of the laser beam can be selected as parameters of the dynamic effect and can be changed individually or in any combination depending on time for the dynamic effect.

[0302] Exemplary process parameters and the modifications generated thereby A plurality of experiments 1 to 5 were carried out, in which modifications were introduced into a glass substrate using a laser. The relevant process parameters, namely the settings for different laser parameters in particular, information regarding the optical structure (e.g., the offset of the beam on the phase mask or the focal length of the microscope, etc.), as well as the number of bursts ("number of shots") are shown in the following table. The optical structure used in these experiments may be the same as the optical structure described with reference to FIG. 13a, for example.

[0303] Experiments 1 to 5 show examples regarding dynamic effects because each modification was introduced into the substrate by a linearly focused spot that changes over time (due to the time-dependent change in the offset of the laser beam on the phase mask).

[0304] The last four rows of the table contain indications regarding the modifications introduced into each substrate in each of the experiments 1 - 5. In this case, the "length of the modification in the substrate" is measured along the substrate thickness. Also, the indication of the "offset of the modification along the thickness direction of the substrate" indicates the vertical distance between the location of the maximum material damage and the center of the substrate. Information regarding the "modification overlap" indicates how much adjacent modifications resulting from the shift of the energy distribution along the track overlap, where in this case the value is multiplied by 100 and the overlap is indicated in %. (In this case, negative values would indicate the distance between the two modifications) (although that is to say, preferably here, it is preferred to use separate processes to introduce adjacent damage into the substrate material along the track, in other advantageous embodiments it is also conceivable that the modifications propagate continuously within the substrate material). The "maximum substrate thickness" indicates the maximum substrate thickness that can be processed using the process parameters. The processable substrate thickness is advantageously obtained from all single - shot modification lengths taking into account the length of the individual modifications (here the "length of the modification in the substrate") and the modification overlap.

[0305] In the following table, as an example for the dynamic case, each column is related to multiple shots at various depths but the same lateral position. In contrast, FIG. 13c shows the individual modifications corresponding to the static case. The values in column 1 of the table are the result of comparing the central and right - hand modifications in FIG. 13c.

[0306]

Table 2

[0307] Influence of the beam cross - section FIG. 14a shows, on the left, a cubic phase mask with a circular area intended to represent the cross - section of the laser beam incident on the phase mask. By using a laser beam having such a cross - section within the plane of the phase mask, material modifications were introduced into the glass substrate.

[0308] In FIG. 14a, a plan view of the substrate corresponding to the right side is shown. Therefore, the outer surface of the substrate facing the phase mask is shown. Here, on the right side outside, the material modification generated by the primary maximum of the linear focus can be seen. The material modification generated by the secondary maximum of the linear focus forms arrow-shaped / angled outliers.

[0309] FIG. 14b shows a cubic phase mask with an elliptical surface drawn intended to represent a cross-section of another laser beam incident on the phase mask again to the left. By using a laser beam having such an elliptical cross-section within the plane of the phase mask, a material modification was introduced into a further glass substrate.

[0310] In FIG. 14b, a plan view of the substrate corresponding to the right side is shown. Therefore, the outer surface of the substrate facing the phase mask is shown. Here too, on the right side outside, the material modification generated by the primary maximum of the linear focus can be seen. Due to the elongated beam cross-section, the material modification caused by the secondary maximum becomes more compact and has a circular segment-like structure on the outer surface. In the substrate itself, these modified structures are arranged like onion skins with respect to each other. Additionally, a clearer contrast of the modifications caused between or by the primary and secondary maxima can be recognized.

[0311] Based on the more compact damage regions within the substrate, the interference of adjacent modifications is also less. Additionally, during the formation of the separation surface, more suitable crack formation was observed along a plurality of adjacent modifications. Furthermore, this was the same even for a relatively large pitch of, for example, 1 μm or more, or even a relatively large pitch of 10 μm or more. This can be considered to be due to the fact that in some cases, the secondary maximum can extend parallel to the cutting edge.

[0312] The features disclosed in the above description, claims, and drawings may be essential for the various embodiments of the present invention, either individually or in any combination.

Description of Reference Numerals

[0313] 1,1’,1’’,1’’’,1 iv Optical structure section 3,3’,3’’,3’’’,3 iv Laser beam 5,5’,5’’,5’’’,5 iv Phase mask 7,7’,7’’,7’’’,7 iv Focusing optical system 9,9’,9’’,9’’’,9 iv Substrate 11 substrates 13 substrate region 15 energy distribution 17,17’,17’’,17’’’,17 iv Linear focus orbit 19’,19’’,19’’’,19 iv Optical system 21’,21’’,21’’’,21 iv Optical axis 23’,23’’,23’’’,23 iv Deflection optical system 25’,25’’,25’’’,25 iv Central axis line of the laser beam 27’,27’’,27’’’,27 iv Offset 29’,29’’,29’’’ Center point of the phase mask 31’’’ Plate 33 Substrate 35 Region 37 Outer surface 39 iv Center point of the focusing optical system d Distance D,D’,D’’,D’’’,D iv Distance f,f’,f’’,f’’’,f iv Focusing length H Main extension direction R Direction ω0 Beam diameter Δz,Δz1,Δz2 Depth region

Claims

1. A method for controlling an energy distribution introduced into a substrate using at least one linear focus of at least one laser beam, the method comprising: forming at least region-by-region a linear focus within the substrate; at least partially controlling the energy distribution within the substrate by influencing the laser beam using at least one phase mask; wherein influencing the laser beam using the at least one phase mask is performed in a time-dependent manner, whereby the energy distribution changes in a time-dependent manner; method.

2. The at least one phase mask is a phase mask having a third-order phase distribution or a higher-order phase distribution, and / or the phase mask is arranged in the optical path of the laser beam in front of the substrate, and the centroid of the beam cross-section present in the plane of the phase mask has an incidence point on the phase mask. The method according to claim 1.

3. The step of forming the linear focus includes setting the position of the apex of the curved linear focus along the depth region of the substrate, and the position of the apex of the linear focus is (i) set centrally along the depth region of the substrate, or (ii) set along the depth region of the substrate with a distance in the vertical direction from the central position, and the vertical distance along the depth region is (a) more than 0.1% of the thickness of the substrate, and / or (b) less than 50% of the thickness of the substrate. The method according to claim 1.

4. The step of controlling the energy distribution within the substrate further includes setting pulse energy, pulse duration, number of pulses within a burst, energy distribution within a burst, and / or laser wavelength, wherein the pulse energy is set such that the linear focus within the substrate has at least one section along which the substrate material is modified based on the energy deposited within the substrate, and the section (a) has a length greater than 0.1 mm and / or less than 5 mm, (b) has a length greater than 0.3 mm and / or less than 5 mm, (c) has a length greater than 0.5 mm and / or less than 5 mm, (d) has a length greater than 0.7 mm and / or less than 5 mm, (e) has a length greater than 3 mm and / or less than 5 mm, (f) has a length greater than 5 mm, or (g) has a length less than 0.1 mm. The method according to claim 1.

5. (i) The pulse energy is at least temporarily (a) set to 50 μJ or more and / or 5000 μJ or less, (b) set to 100 μJ or more and / or 5000 μJ or less, (c) set to 200 μJ or more and / or 5000 μJ or less, (d) set to 300 μJ or more and / or 5000 μJ or less, (e) set to 400 μJ or more and / or 5000 μJ or less, (f) set to 500 μJ or more and / or 5000 μJ or less, (g) set to 600 μJ or more and / or 5000 μJ or less, (h) set to 1000 μJ or more and / or 5000 μJ or less, (i) set to 1500 μJ or more and / or 5000 μJ or less, (j) set to 2000 μJ or more and / or 5000 μJ or less, (k) set to 2500 μJ or more and / or 5000 μJ or less, (l) set to 3000 μJ or more and / or 5000 μJ or less, (m) set to 3500 μJ or more and / or 5000 μJ or less, (n) set to 4000 μJ or more and / or 5000 μJ or less, (o) set to 4500 μJ or more and / or 5000 μJ or less, (p) set to 5000 μJ or more, or (q) set to 50 μJ or less, and / or (ii) the pulse energy is set, whereby the average linear energy density is (a) 1 μJ / mm or more and / or 1000 μJ / mm or less, (b) 5 μJ / mm or more and / or 1000 μJ / mm or less, (c) 10 μJ / mm or more and / or 1000 μJ / mm or less, (d) 20 μJ / mm or more and / or 1000 μJ / mm or less, (e) 30 μJ / mm or more and / or 1000 μJ / mm or less, (f) 40 μJ / mm or more and / or 1000 μJ / mm or less, (g) 50 μJ / mm or more and / or 1000 μJ / mm or less, (h) 60 μJ / mm or more and / or 1000 μJ / mm or less, (i) 70 μJ / mm or more and / or 1000 μJ / mm or less, (j) 80 μJ / mm or more and / or 1000 μJ / mm or less, (k) 90 μJ / mm or more and / or 1000 μJ / mm or less, (l) 100 μJ / mm or more and / or 1000 μJ / mm or less, (m) becomes 150 μJ / mm or more and / or 1000 μJ / mm or less, (n) becomes 200 μJ / mm or more and / or 1000 μJ / mm or less, (o) becomes 250 μJ / mm or more and / or 1000 μJ / mm or less, (p) becomes 300 μJ / mm or more and / or 1000 μJ / mm or less, (q) becomes 350 μJ / mm or more and / or 1000 μJ / mm or less, (r) becomes 400 μJ / mm or more and / or 1000 μJ / mm or less, (s) becomes 500 μJ / mm or more and / or 1000 μJ / mm or less, (t) becomes 600 μJ / mm or more and / or 1000 μJ / mm or less, (u) becomes 700 μJ / mm or more and / or 1000 μJ / mm or less, (v) becomes 800 μJ / mm or more and / or 1000 μJ / mm or less, or (w) becomes 900 μJ / mm or more, The method according to claim 4.

6. The step of controlling the energy distribution in the substrate comprises: (a) spatially expanding the energy distribution, (b) adapting the position of the maximum material damage caused by the non-linear interaction between the laser and the substrate material, and / or (c) adapting the position of the energy distribution, including (i) after adapting the position of the energy distribution, at least one maximum value of the energy distribution is positioned at the apex of the curved linear focus, and / or (ii) after spatially expanding and / or adapting the position of the energy distribution, modification of the substrate material extending along the entire substrate thickness is carried out or performed, and / or (iii) adapting the position of the energy distribution includes sequentially and continuously adjusting at least in part the influence on the laser beam using the phase mask and the setting of the pulse energy, The method according to claim 1.

7. Influencing the laser beam using the at least one phase mask includes the laser beam being incident offset with respect to the center point of the phase mask, the center point being the location of the phase mask where the laser beam incident on the phase mask is affected by the saddle point of the phase distribution imposed on the phase mask, where the offset is carried out within the mirror plane of the phase distribution and the offset is between 0.1 μm and 5000 μm, The method according to claim 1.

8. (i) The offset is (a) by moving the phase mask relative to the laser beam and / or (b) by means of at least one rotated parallel flat plate made of glass material and / or optical material and / or (c) by means of at least two prisms arranged one behind the other in the optical path, the prisms having the same prism angle and the second prism being arranged rotated by 180° about the optical axis with respect to the first prism and / or (d) set by translating a deflection mirror for deflecting the laser beam and / or (ii) the offset is set by deflecting the laser beam by means of at least one first means, whereby the direction vector of the beam incident on the phase mask forms an angle with the direction vector of the central axis of the phase mask, the angle being 1 / 500 radian or less, the deflection is (a) by means of at least one prism rotatably supported (b) by means of at least one mirror rotatably supported (c) by means of at least one polygon or galvo scanner (d) by means of at least one acousto-optic modulator (e) by means of at least one liquid crystal spatial light modulator on silicon and / or (f) set by means of a first means having at least one microelectronic mirror component, a second means identical to the first means is further provided and is arranged in the optical path in front of or behind the phase mask and / or is controlled in synchronization with the first means for deflecting the laser beam so that the laser beam is incident perpendicularly on the phase mask and / or the substrate and / or extends parallel but offset with respect to the path before deflection using the first means, The method according to claim 7.

9. The laser beam is affected by different regions of the different phase masks, and the centroid of the beam cross-section present in the plane of the phase mask has different points of incidence on the phase mask during different periods. The method according to claim 1.

10. By being affected by a time-dependent influence, moving the energy distribution in the substrate from a greater depth to a shallower depth and / or along the focal trajectory in the substrate. The method according to claim 1.

11. Influencing the laser beam using the at least one phase mask includes changing the intensity distribution of the laser beam on the phase mask. The method according to claim 1.

12. Using the energy distribution introduced using at least a part of the linear focus. (a) The substrate is corrected at least region by region in terms of material properties that are its density, its refractive index, its stress value and / or etching rate. (b) Microcracks are generated at least region by region in the substrate material and / or (c) Material is removed and / or extruded from the substrate at least region by region. In a plurality of successively consecutive substrate regions, the substrate material is thus modified, removed and / or extruded along a straight line or a contour of any shape. The method according to claim 1.

13. Two or more linear foci of two or more laser beams within the same region in the substrate are correspondingly formed, and the energy distributions introduced into the substrate by them are correspondingly controlled respectively. (a) The energy distributions introduced by the individual linear foci are different, and the maxima of the individual energy distributions are at different positions within the substrate and / or (b) the trajectories of the two or more linear foci are congruent. The method according to claim 1.

14. The orientation of at least one segment of the linear focus within the substrate is set by controlling the energy distribution within the substrate relative to the main propagation direction of the laser beam in the substrate and further adapting the focal position within the substrate material. The adaptation of the focal position is performed by changing the distance between the focusing optical system and the substrate, and / or the thickness of the substrate is less than half of the length of the linear focus potentially possible for a given optical structure along the thickness extension direction of the substrate, and the pulse energy and / or beam diameter are selected such that the substrate is modified at its full depth or not at its full depth. The method according to claim 1.

15. (i) The linear focus is the focus of an airy beam. (ii) The linear focus has a maximum deflection from a straight path of more than 20 μm, more than 40 μm, more than 60 μm, more than 80 μm, or more than 100 μm. (iii) The laser beam is emitted by a pulsed laser. (iv) The wavelength of the laser beam is selected from the wavelength range between 200 nm and 1500 nm, the microscope objective lens or the Fourier lens of the focusing optical system for focusing the laser beam on the substrate has a focal length of 10 to 20 mm, and the coefficient of the cubic phase (laser parameter β) is 0.5×10 ３ / m to 5×10 ３ / m, the diameter of the raw beam (laser parameter ω ０ ) has a value between 1 mm and 10 mm, the pulse duration (laser parameter τ) has a value of 0.1 to 10 ps, the pulse energy (laser parameter E ｐ ) has a value between 1 and 1500 μJ, and / or the number of pulses in the burst (laser parameter N) has a value between 1 and 200, and / or (v) The pulse energy of the laser is sufficient to modify the substrate in at least one material property along a specific section of the linear focus, or to remove or extrude material from the substrate, and the section is shorter than the extension of the substrate area to be modified or removed or extruded in its material property. The method according to claim 1.

16. The region modified within the substrate is opened by the generation of mechanical and / or thermal stress and / or by an etching method in order to generate through-holes and / or blind holes in the substrate material, and / or The region modified within the substrate is opened by mechanical, thermal and / or chemical processes along a closed contour and / or along a modification extending from one substrate side to the other substrate side in order to generate an internal or external contour having a shaped side surface. The method according to claim 1.

17. During at least the control of the energy distribution, at least one auxiliary substrate is arranged on the substrate, and the linear focus extends at least partially into the auxiliary substrate. The method according to claim 1.

18. The linear focus is completely enclosed within the substrate, and the method further includes that material is removed from the substrate at least region by region, whereby the material enclosed and modified within the substrate becomes at least partially and / or region by region accessible from the outside, and the removal of material from the substrate is carried out using etching. The method according to claim 1.

19. The step of controlling the energy distribution within the substrate further includes (i) the laser beam having spherical aberration, and / or (ii) the spherical aberration of the laser beam being set. The method according to claim 1.

20. The laser beam propagates through an optical element having spherical aberration, whereby the spherical aberration of the laser beam is at least partially set. The method according to claim 19.

21. The fourth-order spherical aberration has an intensity of 0.02 / (f*w0^2) or more, where f is the focal length of the imaging system and w0 is the diameter of the laser beam. The method according to claim 19.

22. Due to the spherical aberration, the focus formed within the substrate is (a) extended by 5% or more and / or 100% or less. (b) Extended by 10% or more and / or 100% or less, (c) Extended by 15% or more and / or 100% or less, (d) Extended by 20% or more and / or 100% or less, (e) Extended by 25% or more and / or 100% or less, (f) Extended by 30% or more and / or 100% or less, (g) Extended by 35% or more and / or 100% or less, (h) Extended by 40% or more and / or 100% or less, (i) Extended by 50% or more and / or 100% or less, or (j) Extended by 60% or more and / or 100% or less, The method according to claim 19.

23. The spherical aberration of the laser beam changes temporally in the region of the linear focus due to the temporal change of the incident point of the laser beam on the phase mask and / or on the optical element which is the microscope objective lens of the optical structure part. The method according to claim 19.

24. The center point of the laser beam incident on the optical element is incident on the optical element with at least a temporary offset with respect to the optical axis of the optical element, and the offset changes temporally. The method according to claim 19.

25. A certain offset and / or a maximum offset are (a) Set to 20 mm or less and / or 0.001 mm or more, (b) Set to 15 mm or less and / or 0.001 mm or more, (c) Set to 10 mm or less and / or 0.001 mm or more, (d) Set to 5 mm or less and / or 0.001 mm or more, (e) Set to 3 mm or less and / or 0.001 mm or more, (f) Set to 2.5 mm or less and / or 0.001 mm or more, (g) Set to 2 mm or less and / or 0.001 mm or more, (h) Set to 1.5 mm or less and / or 0.001 mm or more, or (i) Set to 1 mm or less and / or 0.001 mm or more, The method according to claim 24.

26. The optical element is a lens, and the lens has a spherical curvature at least for each region. The method according to claim 20.

27. The spherical aberration is a spherical aberration of the fourth or higher order. The method according to claim 19.

28. The spherical aberration is a spherical aberration by a Zernike polynomial having an exponent m = 0 and n = 2k when the integer k > 2. The method according to claim 19.

29. The influence of the spherical aberration and the phase mask on the laser beam is adjusted sequentially and continuously by sequentially and continuously adjusting the incident point of the laser beam on the optical element and the incident point of the laser beam on the phase mask. The method according to claim 20.

30. By setting the spherical aberration, the energy distribution, intensity, and / or intensity distribution of the rear end section of the linear focus along the main extension direction of the linear focus can be set, changed, or expanded. The method according to claim 19.

31. By setting the spherical aberration, the positioning of the energy distribution along the linear focus and along the trajectory of the linear focus can be changed and / or set. The method according to claim 19.

32. The step of controlling the energy distribution in the substrate further includes that the wavelength of the laser beam is changed depending on time, and an optical element for refracting the laser beam depending on the wavelength is provided in the optical path of the laser beam. The method according to claim 1.

33. The laser beam has an elongated elliptical beam cross-section at least intermittently for each section, and the beam cross-section changes over time. The method according to claim 1.

34. A plurality of material modifications are introduced into the substrate, and the distance between adjacent material modifications and / or the distance in a plane parallel to the outer surface of the substrate is 1 μm or more. The method according to claim 1.

35. (i) The substrate is transparent and made of glass and / or glass ceramic, has a first outer surface, and / or extends parallel to the first outer surface, and / or has a second outer surface on the opposite side of the first outer surface. And / or (ii) The substrate has a thickness measured between the first outer surface and the second outer surface, and the thickness is (a) 10 μm or more, and / or (b) 10 mm or less. The method according to claim 1.

Images