Method for processing glass by alkaline etching

Abstract

The object of the invention is to provide a glass processing method in which a glass element (1) is provided and glass material is removed from the glass element (1), in which the removal is carried out by etching and in which an alkaline etching medium (4) in an organic solvent is used.

Description

[0001] This application is a divisional application of patent application 202111196667.X, entitled "Method for processing glass by alkaline etching". Technical Field

[0002] This invention generally relates to processing glass in the form of fine structures or cuts, or to creating external contours, or to removing glass from a glass element having an initial thickness to a lower target thickness. In particular, this invention relates to a method for processing or structuring glass by etching, and the processed or structuring glass elements that can be manufactured therefrom. Background Technology

[0003] Precise structuring of transparent, translucent, and opaque glass is highly significant in many applications. This requires precision within the micrometer range. Structuring involves creating holes, cavities, and channels in circular, angular, or arbitrary freeform shapes. For usability across a wide range of applications, the processing should leave no damage, residue, or stress on the edge areas or volumes of the substrate.

[0004] DE102018005218 A1 relates to a material modification method in which, relative to the focal point of a solid-guided laser beam, the path simultaneously possesses a motion component perpendicular to it, in addition to a two-dimensional motion component. In selective laser etching, high-intensity laser radiation causes localized, crack-free modification of the irradiated material.

[0005] DE102013103370 A1 describes a method for introducing perforations into a glass substrate. In this case, an opening is first formed in the glass substrate by laser radiation, followed by removal of the material by etching.

[0006] In addition, DE102018100299 A1 discloses a method in which a glass element is exposed to an etching medium that removes the glass of the glass element in an alkaline etching solution at a slow removal rate of less than 8 µm / h, and the filamentary cracks widen to form channels, and circular, substantially hemispherical depressions are introduced in the channel walls.

[0007] A drawback of the known methods is that it is very difficult to manufacture complex filamentary structures within the volume of a glass or glass-ceramic substrate at a stable cost and with high quality (e.g., in terms of component strength). Furthermore, some glasses cannot be etched in water-based etching media. Additionally, the processing time of this method needs improvement. Summary of the Invention

[0008] The inventors have solved this problem. The object of this invention is to provide a nearly anhydrous alkaline etching process that is fast and inexpensive for glass processing or structuring. The object of this invention is unexpectedly achieved according to the invention itself.

[0009] The present invention provides a glass processing method, wherein a glass element is provided and glass material is removed from the glass element, wherein the removal is performed by etching, and wherein an alkaline etching medium in an organic solvent is used.

[0010] In particular, the glass material is selectively or partially removed from the glass element, or uniformly and isotropically removed over the entire surface of the glass element.

[0011] Furthermore, preferably, no other additives are used. Organic solvents are present as the main component of the etching process, and in particular, their content is greater than 30% (wt%) by weight.

[0012] Currently, etching is performed in water-based alkaline etching media. However, the boiling points of certain organic solvents are much higher than those in water-based alkaline etching media. Therefore, etching in organic solvents can be carried out at higher temperatures, and thus at a faster rate. Furthermore, because the degradation products dissolve differently, some glasses that are difficult to structure in water-based etching media can be more easily structured in organic solvents.

[0013] Therefore, the etching medium is almost water-free. Anhydrous etching medium means that the water content of the etching medium is preferably less than 5% (wt%) by weight, more preferably less than 1% (wt%) by weight. This is mainly due to ambient humidity, which unfortunately cannot be completely avoided. In practice, the solution should be anhydrous. In contrast to aqueous etching, current anhydrous processes utilize different properties, such as increased boiling point and altered solubility.

[0014] Organic compounds having at least one hydroxyl group are particularly suitable for dissolving basic reagents. Preferably, polyols or organic compounds having at least two hydroxyl groups are used.

[0015] The organic solvent preferably comprises an alcohol. The alcohol may be, in particular, a polyol, or specifically a polyhydroxy alcohol, to improve the solubility of the hydroxide. Diols or glycols, such as ethylene glycol, are particularly suitable. Glycerol is an example of a suitable solvent or solvent component.

[0016] In addition, the organic solvent can be a mixture of organic compounds, such as a mixture of polyols (i.e., polyhydroxy alcohols), or a mixture of polyols with one or more other organic compounds.

[0017] Ethylene glycol has a boiling point of approximately 197°C. Therefore, its maximum processing temperature is much higher than that of water-based etching media. Because of the presence of insoluble degradation products, some glasses cannot be etched in water-based etching media but can be processed in alcohol, thus allowing for the processing or structuring of other glasses as well.

[0018] Furthermore, since the highest etching temperature in organic solvents is much higher than that in water-based solvents, etching is preferably performed at a temperature greater than 130°C, preferably greater than 150°C, and particularly preferably greater than 170°C. Therefore, the processing speed can be higher.

[0019] Sodium hydroxide (NaOH) or potassium hydroxide (KOH) are particularly suitable as alkaline etching media. KOH is preferred as an alkaline etching media. KOH is especially suitable for use as an etching media for fine-structure etching.

[0020] It has been shown that a concentration of KOH in an organic solvent (especially ethylene glycol) greater than 4 mol / L, preferably greater than 5 mol / L, particularly preferably greater than 6 mol / L, but less than 30 mol / L is particularly preferred.

[0021] The object of this invention is to provide a rapid, virtually anhydrous etching process. Therefore, if a glass element is exposed to an alkaline etching medium in an organic solvent at an etching temperature greater than 130°C, the glass material of the glass element is preferably removed at a removal rate or etching rate of at least 10 μm / hour, preferably greater than or equal to 20 μm / hour.

[0022] The glass element according to the invention is preferably a disc-shaped or plate-shaped thin glass having two opposing side surfaces. The thickness of the glass element can be less than 1500 micrometers (µm) or 8 mm, 10 mm, or 20 mm to 100 mm. Therefore, the glass is suitable for processing fine structures or cuts, for creating external contours, and for removing glass from a glass element with an initial thickness to a lower target thickness. Thin glass and high temperature accelerate this process and save or reduce time. Therefore, the invention provides a glass element, preferably borosilicate glass or soda-lime silicate glass, which can be manufactured or commercially available from Schott AG in Mainz, Germany.

[0023] The present invention also includes a glass element, preferably comprising one of the following glass components, in weight percentage (wt-%): SiO2 63 – 83 Al2O3 0 – 7 B2O3 5 – 18 Li₂O + Na₂O + K₂O 4 – 14 MgO + CaO + SrO + BaO + ZnO 0 – 10 TiO2 + ZrO2 0 – 3 P2O5 0 - 2 (An example of glass with the given composition is glass D263 manufactured by Schott AG in Mainz, Germany.) or SiO2 50 – 75 Al2O3 7 – 25 B2O3 0 – 20 Li₂O + Na₂O + K₂O 0 - 0.1 MgO + CaO + SrO + BaO + ZnO 5 – 25 TiO2 + ZrO2 0 – 10 P2O5 0 - 5 (An example of glass with the given composition is glass AF32 manufactured by Schott AG in Mainz, Germany.) or SiO2 75 – 85 B2O3 8 – 18 Al2O3 0.5 - 4.5 Na₂O 1.5 - 5.5 K2O 0 - 2, (An example of this component is Boro33 glass manufactured by Schott AG in Mainz, Germany.) or SiO2 55 – 75 Na2O 0 – 15 K2O 2 – 14 Al2O3 0 – 15 MgO 0 – 4 CaO 3 – 12 BaO 0 – 15 ZnO 0 – 5 TiO2 0 – 2 (An example of this composition is glass B270 manufactured by Schott AG in Mainz, Germany.)

[0024] Generally, according to the present invention, borosilicate or soda-lime silicate glasses with titanium content are particularly suitable for processing or structuring in alkaline etching media with organic solvents. Titanium compounds are generally poorly soluble in water, or, like titanium carbide and titanium dioxide, completely insoluble in water. In contrast, titanium compounds are generally highly soluble in organic solvents. Therefore, glass elements containing titanium compounds do not form undesirable solid precipitates in organic solvents.

[0025] Furthermore, silicate glasses with low alkali metal content are particularly suitable for processing or structuring according to the invention. Excessively high alkali metal content makes etching more difficult. This makes the glass particularly suitable for controlled etching using alkaline etching media. According to an improvement of the invention, the glass element is specified as silicate glass with an alkali metal oxide content of less than 17% by weight.

[0026] The method according to the invention can provide a glass element that is pre-damaged by introducing a crack using a laser beam from an ultrashort pulse laser, wherein the crack is propagated by means of the alkaline etching medium. The term "crack" is understood below as a material modification, gap, or very fine channel that may or may not penetrate the substrate.

[0027] The glass element can be pre-damaged using a laser beam by introducing filamentary cracks, wherein the filamentary cracks are extended by an alkaline etching medium to form channels.

[0028] Filamentous cracks can be continuous, thin, open channels. However, materials can also contain only filamentous or linear variations. Hybrid forms are also possible, where cavities or material variations extend along the line. For example, one form is short cracks arranged in a chain along the line, caused by the periodic self-focusing of a powerful laser beam.

[0029] According to the present invention, filamentary cracks are formed by means of a laser beam from an ultrashort pulse laser. Then, preferably, the filamentary cracks are extended or widened by a selective etching process using an alkaline etching medium in an organic solvent to form channels.

[0030] A suitable laser for this purpose is an Nd:YAG laser, for example, with a radiation wavelength of 1064 nm. According to one embodiment, the ultrashort pulse laser operates at a repetition frequency in the range of 10 kHz to 400 kHz, preferably in the range of 30 kHz to 200 kHz. The repetition frequency and scanning speed of the laser beam on the glass element can be selected so that the lateral distance (i.e., spacing) between adjacent cracks is adjustable. The pulse duration is less than 100 picoseconds, preferably less than 20 ps. A suitable average power of the laser is in the range of 50 W to 500 W.

[0031] Another suitable laser for this purpose is a Yb:YAG laser, for example, with a radiation wavelength of 1030 nm or 513 nm. According to this embodiment, the ultrashort pulse laser operates at a repetition frequency in the range of 10 Hz to 50 MHz, preferably in the range of 20 Hz to 40 MHz. The pulse duration is less than 20 picoseconds, preferably less than 10 ps, ​​and as low as 0.5 ps. A suitable average power for the laser is in the range of 20 W to 500 W.

[0032] In other embodiments, the laser can operate in the wavelength range of 1100 nm to 100 nm (UV) and the pulse duration is 100 ps to 200 fs.

[0033] The method according to the invention specifically includes the following steps: increasing the diameter of adjacent channels arranged along a predetermined path using an alkaline etching medium until the glass between the channels is removed, and the channels bond together, thus separating the glass element along the path. Using this method, the outer contour and cutouts of the glass element can be formed. As with any wet chemical etching process, the edges of the glass element can be slightly bonded together.

[0034] Therefore, according to the present invention, even fine filamentary cracks with a diameter of no more than 1 μm, preferably no more than 0.8 μm, and particularly preferably no more than 0.5 μm, can be widened by an etching medium. Due to this widening, channels are formed in the glass element.

[0035] In a particular embodiment of this process, the predetermined path of the channel forms a closed path, such as a circular or rectangular path, such that the separation of the alkaline etching medium along the path results in an opening in the glass element. This opening opens toward one side of the substrate, i.e., toward the side surface, and thus defines a cut on the surface of the substrate. The opening can have different geometries or more complex structures.

[0036] The glass composition, the composition of the alkaline etching medium, the removal or etching rate, and the etching temperature can be adjusted to form a predetermined cone angle relative to the corresponding side at one edge or wall of the channel. However, channels or edges with smaller cone angles or vanishing cone angles can be formed, meaning that the angle between the side and the channel wall or edge is 90° or at least very close to 90°. Attached Figure Description

[0037] The present invention will now be described in more detail based on preferred embodiments and with reference to the accompanying drawings. In the drawings, the same reference numerals denote the same or corresponding elements in each case.

[0038] Figure 1 An apparatus for laser processing of glass components as preparation for subsequent etching is shown; Figure 2A glass element with introduced filamentary cracks is shown in the top view; Figure 3 A glass element with channels introduced along filamentary cracks is shown; Figure 4 A glass element is shown, in which channels are increased due to etching and joined together on the sides; Figure 5 The glass element is shown after partial separation; Figure 6 The etching rate of Boro33 glass in KOH aqueous solution or KOH glycol solution at different temperatures is shown as a function of KOH concentration. Figure 7 The solubility of titanium in various etching media is shown; Figure 8 It shows Figure 1 The variation of the device shown is used to introduce a series of cracks or defects inside the glass element; Figure 9 This shows the use of subsequent etching. Figure 8 Glass components processed by the equipment shown; Figure 10 An embodiment of an apparatus for locally etching glass elements is shown. Detailed Implementation

[0039] Figure 1 An example of the operation of a laser processing apparatus 20 is shown, by which a filamentary crack 32 can be introduced into a glass element 1 to create a channel 5 at the location of the filamentary crack 32 in a subsequent etching process. The laser processing apparatus 20 includes an ultrashort pulse laser 30 having a pre-focusing optics 23 and a positioning device 17. The positioning device 17 allows the impact point 73 of the laser beam 27 of the ultrashort pulse laser 30 to be laterally positioned on one side 2 of the plate-shaped glass element 1 to be processed. In the example shown, the positioning device 17 includes an xy stage on which the other side 3 of the glass element 1 is placed. However, alternatively or additionally, the optics can be moved to move the laser beam 27, thereby moving the impact point 73 of the laser beam 27 while the glass element 1 remains fixed. The focusing optics 23 then focuses the laser beam 27 to form a focal point that is elongated along the direction of the beam, i.e., correspondingly laterally, and particularly perpendicularly, to the irradiated side 2. This focal point can be generated, for example, by means of a conical lens (so-called axial pyramid) or a lens with large spherical aberration. The control of the positioning device 17 and the ultrashort pulse laser 30 is preferably performed using a programmable computer 15. In this way, a predetermined pattern of filamentary cracks 32 distributed laterally along the side 2 can be generated, particularly by inputting position data preferably from a file or via a network.

[0040] According to a working example, the laser beam 27 can use the following parameters: a laser beam wavelength of 1064 nm, typically for an Nd:YAG laser. A laser beam 27 with an initial beam diameter of 12 mm is generated and then focused by an optics device in the form of a biconvex lens with a focal length of 16 mm. The pulse duration of the ultrashort pulse laser is less than 20 ps, ​​preferably about 10 ps. The pulses are transmitted in pulse trains of two or more pulses, preferably four or more. The pulse train frequency is 12-48 nm, preferably about 20 nm, and the pulse energy is at least 200 microjoules, correspondingly, the pulse train energy is at least 400 microjoules.

[0041] Subsequently, after introducing one or more filamentary cracks 32, the glass element 1 is removed and placed in an alkaline etching medium. In the etching process, glass is removed along the filamentary cracks 32 in the alkaline etching medium, thereby introducing channels 5 into the glass element 1 at the locations of these cracks 32.

[0042] Etching is performed using an alkaline etching medium in an organic solvent.

[0043] Preferably, a KOH solution in an organic solvent (preferably ethylene glycol) is used as the alkaline etching bath, wherein the concentration of KOH in the organic solvent is greater than 4 mol / L, preferably greater than 5 mol / L, particularly preferably greater than 6 mol / L, but less than 30 mol / L. In one embodiment of the invention, etching is performed at a temperature greater than 130°C, preferably greater than 150°C, particularly preferably greater than 170°C.

[0044] Figure 2 A top view of side 2 shows a glass element 1 having a plurality of filamentary cracks 32, which are etched into the glass element 1 in a specific pattern by computer-controlled actuation of the positioning device 17 and the ultrashort pulse laser 30. Specifically, as an example, the filamentary cracks 32 are introduced into the glass element 1 along a predetermined path in the form of a closed rectangular path or line. The corners of the line may also be slightly rounded. Those skilled in the art will see that this processing can form not only rectangular paths, but also paths or lines of any shape.

[0045] Figure 3 The image shows a glass element 1 after a subsequent etching step, where filamentary cracks propagate by an alkaline etching medium and form channels 5 arranged adjacent to each other along a predetermined path and rowed along that path. The diameter of the channels 5 increases with the alkaline etching medium until the glass between the channels 5 is removed, and the channels 5 can coalesce, and the glass element 1 can be separated along that path. For example, according to... Figure 3The predetermined path of channel 5 shown forms a closed rectangular path, causing the alkaline etching medium to separate along the path, resulting in an opening in the glass element. Of course, the predetermined path can also be other shapes, such as circular or annular.

[0046] Figure 4 A glass element 1 is shown, wherein channels 5 are joined on the sides due to etching. Embodiments of the invention are based on increasing the diameter of the channels 5 by etching until the glass between the channels 5 is removed and the channels 5 are joined.

[0047] Figure 5 The glass element 1 after separation along the path is shown. Because the channel 5 is arranged along a rectangular, closed separation line, the inner portion detaches and forms an opening 13 in the glass element 1. The glass element 1 is indicated by the shaded area around the glass element 1, thereby distinguishing the element from the opening 13 (e.g., the channel 5 in the figure), which are the inner portions, respectively.

[0048] Figures 2 to 5 An example of an embodiment of the method of the present invention is shown, wherein: The laser beam 27 is transmitted along a predetermined path to the impact point 73 on the glass element 1; Multiple fine filamentary cracks 32 that are adjacent to each other along the path are introduced into the glass element 1; Fine filamentary cracks 32 are extended through an alkaline etching medium in an organic solvent to form channels 5; and In this process, the diameter of the channels 5 arranged adjacent to each other along a predetermined path is increased by an alkaline etching medium until the glass between the channels 5 is removed and the channels 5 are joined together, and the glass element 1 can be separated along the path.

[0049] Channel 5 typically has a basic tubular cylindrical shape or is a tube with cylindrical walls. Here, a slight taper may exist from the opening 13 at side 2 to the middle of the glass element 1. When the generally cylindrical channel 5 is joined together during the widening process during the etching operation, ridges 52 are formed at adjacent locations. Generally, not limited to Figure 4 As an example, one embodiment of the invention provides channels 5 adjacent to each other to form ridges 52, which are located between the channels 5 and extend parallel to the longitudinal direction of the channels 5. These ridges 52, or ribs, extend correspondingly parallel to the longitudinal direction of the channels 5, and thus in Figure 4 The area in the transition region between adjacent channels 5, as described, can only be considered as a serrated or toothed element. However, if etching continues, the ridges will flatten and may no longer be visible.

[0050] Preferably, the glass composition, the composition of the alkaline etching medium, the removal or etching rate, and the etching temperature are adjusted to form a predetermined cone angle at one edge 10 or wall of the channel 5 relative to the corresponding side 2, 3.

[0051] At removal rates of at least 10 μm / h, about 15 μm / h to preferably equal to or greater than 20 μm / h, a fairly vertical cavity still exists, resulting in a cone angle in the range of 90°+ / -5°, preferably 90°+ / -3°, and particularly preferably 90°+ / -1°.

[0052] One object of the present invention is to provide a rapid, almost waterless etching process. Therefore, if the glass element is exposed to an alkaline etching medium in an organic solvent at an etching temperature greater than 130°C, the glass material of the glass element is preferably removed at a removal rate or etching rate of at least 10 μm per hour, preferably greater than or equal to 20 μm per hour.

[0053] Because many organic solvents, such as alcohols, especially ethylene glycol, have higher boiling points than water-based alkaline etching media, etching in organic solvents can be performed at higher temperatures, thus resulting in faster etching speeds.

[0054] Figure 6 The etching rates of Schott AG borosilicate glass Boro33 with different KOH aqueous solution concentrations at different temperatures are shown. Boro33 has the composition given above and a thickness of 1300 µm. These measurements at 70°C, 100°C, 120°C, and 140°C are compared with the etching rates of a 6 mol / L KOH ethylene glycol (EG) solution at 140°C and 175°C.

[0055] The boiling point of a 6 mol / L KOH aqueous solution is approximately 115 °C, that of a 15 mol / L KOH aqueous solution is approximately 140 °C, and that of a 6 mol / L KOH-ethylene glycol (EG) solution is approximately 195 °C. Therefore, the etching temperature is limited by the boiling point of the solvent.

[0056] like Figure 6As shown, the etching rate in a 6 mol / L KOH ethylene glycol solution at 140 °C reached 4 μm / h. This etching rate is higher than that of all water-based etching solutions with the same KOH molar concentration. However, the etching rate of a 6 mol / L KOH ethylene glycol solution at 175 °C was measured to be even higher at 21 μm / h. This etching rate is an order of magnitude higher than that achievable with KOH aqueous solution. Furthermore, for borosilicate glass D263 from Schott AG in Mainz, Germany, with the above composition, an etching rate close to 14 µm was achieved at 175 °C using a 6 mol / L KOH ethylene glycol solution.

[0057] In contrast, measurements show that the etching rate of a 6 mol / L KOH aqueous solution at approximately 100°C is less than 4 µm per hour, and the etching rate of a 15 mol / L KOH aqueous solution at approximately 120°C is less than 10 µm per hour. The etching rate of a 6 mol / L KOH glycol solution is even significantly higher than that of a water-based KOH solution at high temperatures and high KOH molar concentrations, as evidenced by the measured etching rate of an 18 mol / L solution at 140°C.

[0058] The solubility of degradation products from etching in water often varies considerably. Some glasses are difficult to structure in water-based etching media because components with low solubility may precipitate. However, it has been shown that these glasses can generally be etched and structured more easily in organic solvents. Specifically, according to the present invention, titanium-containing borosilicate glasses or soda-lime silicate glasses are particularly suitable for processing or structuring in alkaline etching media containing organic solvents. Therefore, glass elements containing titanium compounds in organic solvents do not form undesirable solid precipitates. Consequently, titanium-containing glass elements have a positive impact on processing time.

[0059] Figure 7 The bar chart illustrates an example of titanium solubility. Specifically, the solubility of etching solutions in 3 mol / L KOH aqueous solution (left column) and 6 mol / L KOH aqueous solution (middle column) is compared with the solubility of etching solutions in 6 mol / L KOH glycol solution. The bar chart shows that the solubility in organic solvents is almost 10 times higher than that of the equivalent water-based solution with 6 mol / L KOH, and more than 20 times higher than that of the 3 mol / L KOH aqueous solution.

[0060] This disclosure is not limited to ethylene glycol as a solvent, but is only used for exemplary embodiments discussed with reference to the accompanying drawings. For example, other multivalent organic compounds, preferably having high boiling points, may also be used. Various organic compounds can be mixed to adjust the properties of the etching solution. Furthermore, the etching solution may contain more than one basic component. For example, a combination of KOH and NaOH may be used.

[0061] Figure 8 It shows Figure 1 A variation of the device is shown for introducing a series of localized or point-like cracks within the glass element 1. For example, instead of forming straight, elongated filamentary lines, a tiny focal point moves along an arbitrary path through the material, producing a small modification at each focal point, such that the movement of the focal point through the material forms a modification curve that contacts the surface at a certain point. Subsequently, the modified structure is selectively etched, thereby creating a 3D structure within the material. Thus, the focusing optics 23 of the laser beam 27 of the ultrashort pulse laser 30 can be guided into the body of the glass element 1 by a scanning motion on one side 2. To modify the material, the path of the localized or point-like cracks 33 is written into the body of the glass element 1 using the laser beam 27, thereby guiding the focal point of the laser beam 27 relative to the body, such that the path has a two-dimensional motion component and a motion component perpendicular to it. This laser-induced modification allows for a shorter etching rate in subsequent wet chemical processes. Due to the almost anhydrous selective alkaline etching, 3D structures or 3D objects in the form of undercuts or curves can be produced from the bulk in this way.

[0062] Figure 9 This shows the use of subsequent etching. Figure 8 The glass element 1 processed by the apparatus shown is wherein a previous local or point crack 33 inside the glass element 1 is expanded by, for example, an alkaline etching medium 4 to form a channel 5.

[0063] Figure 10 An embodiment of an apparatus for localized etching of a glass element is shown. An electrode 35 is immersed in a container 37 containing an alkaline etching medium 4 to generate a static electrostatic discharge in the form of a spark 39, thereby forming a recess 41 on the side 2 of the glass element 1. Alternatively, another local heating element can be used instead of the electrode 35 to locally etch the glass element 1 in a nearly anhydrous alkaline etching medium 4. Therefore, precise chemical etching of the aforementioned glass components is accelerated by heat treatment. And no intermediate or post-processing is required. Micropores several millimeters deep can be drilled in seconds, and channels hundreds of micrometers deep can be created effortlessly. Glass several millimeters thick can also be removed.

[0064] List of reference numerals in the attached diagram: Glass element 1 Side view 2, 3 Alkaline etching medium 4 Channel 5 Edge 10 1 opening 13 Computer 15 Positioning device 17 Laser processing equipment 20 Focusing Optical Devices 23 Laser beam 27 30 Ultrashort Pulse Laser 32 fine filamentous cracks Localized or point-like cracks 33 Electrode 35 Container 37 Spark 39 Recess 41 Ridge 52 between channels 5 Impact point 73.

Claims

1. A glass processing method, wherein, A glass element (1) is provided, and glass material is removed from the glass element (1), wherein the removal is performed by etching, and wherein an alkaline etching medium (4) in an organic solvent is used, wherein the removal comprises: introducing a crack into the glass element along a predetermined path using a laser beam from an ultrashort pulse laser; and extending the crack in the glass element by etching with an alkaline etching medium in an organic solvent to form a channel, increasing the diameter of the channels arranged adjacent to each other along the predetermined path by the alkaline etching medium until the glass between the channels is removed and the channels are joined together, and the glass element is thereby separated along the path, wherein the water content of the alkaline etching medium is less than 5% by weight, and the organic solvent comprises an alcohol.

2. The method according to claim 1, wherein, The glass material is selectively or partially removed from the glass element (1), or uniformly and isotropically removed from the entire surface of the glass element (1).

3. The method according to claim 1 or 2, wherein, The alkaline etching medium (4) has a water content of less than 1% (wt%) by weight.

4. The method according to claim 1 or 2, wherein, The organic solvent includes polyhydroxy alcohols, particularly diols, and more preferably ethylene glycol.

5. The method according to claim 1 or 2, wherein, The organic solvent is a mixture of polyols.

6. The method according to claim 1 or 2, wherein, The alkaline etching medium (4) is potassium hydroxide (KOH) or sodium hydroxide (NaOH). Preferably, the concentration of KOH is greater than 4 mol / L, more preferably greater than 5 mol / L, particularly preferably greater than 6 mol / L, but less than 30 mol / L.

7. The method according to claim 1 or 2, wherein, Etching is performed at a temperature greater than 130°C, preferably greater than 150°C, and particularly preferably greater than 170°C.

8. The method according to claim 1 or 2, wherein, The glass element (1) is a disc-shaped or plate-shaped thin glass with a thickness of less than 1500 μm.

9. The method according to claim 1 or 2, wherein, The glass element (1) is exposed to the alkaline etching medium (4), which removes material of the glass element (1) at a removal or etching rate of at least 10 μm per hour, preferably greater than or equal to 20 μm per hour.

10. The method according to claim 1 or 2, wherein, The glass element (1) is borosilicate glass or sodium-calcium silicate glass.

11. The method according to claim 1 or 2, wherein, The glass element (1) contains titanium.

12. The method according to claim 1 or 2, wherein, The glass element (1) has one of the following glass components, in weight percentage: SiO2 63 – 83 Al2O3 0 – 7 B2O3 5 – 18 Li₂O + Na₂O + K₂O 4 – 14 MgO + CaO + SrO + BaO + ZnO 0 – 10 TiO2 + ZrO2 0 – 3 P2O5 0 - 2 or SiO2 50 – 75 Al2O3 7 – 25 B2O3 0 – 20 Li₂O + Na₂O + K₂O 0 - 0.1 MgO + CaO + SrO + BaO + ZnO 5 – 25 TiO2 + ZrO2 0 – 10 P2O5 0 - 5 or SiO2 75 – 85 B2O3 8 – 18 Al2O3 0.5 - 4.5 Na₂O 1.5 - 5.5 K2O 0 - 2 or SiO2 55 – 75 Na2O 0 – 15 K2O 2 – 14 Al2O3 0 – 15 MgO 0 – 4 CaO 3 – 12 BaO 0 - 15 ZnO 0 - 5 TiO2 0 - 2.

13. The method according to claim 1 or 2, wherein, The predetermined path of the channel forms a closed circular or rectangular path, such that the separation of the alkaline etching medium (4) along the path results in an opening in the glass element (1). The glass composition, the composition of the alkaline etching medium (4), the removal or etching rate, and the etching temperature are adjusted to form a predetermined cone angle at one edge (10) of the channel relative to the corresponding side (2, 3).

14. The method according to claim 1 or 2, wherein, The glass element (1) is glass with a thickness of up to 100 mm.

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