Method for processing glass by alkaline etching

Abstract

It is an object of the present invention to provide 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 carried out by etching, and wherein an alkaline etching medium (4) in an organic solvent is used.

Description

Technical Field

[0001] The present invention generally relates to processing glass to form fine structures or cuts, or to produce external contours, or to remove glass from a glass element having an initial thickness to a lower target thickness. In particular, the present invention relates to a method for processing or structuring glass by etching, and processed or structured glass elements that can be produced thereby. Background Art

[0002] Precise structuring of transparent, translucent, and opaque glass is of great interest in many applications. This requires precision in the range of a few micrometers. Structuring involves holes, cavities, and channels with round or angular shapes or any free-form shapes. To be able to use it in a wide range of applications, the processing must leave no damage, residues, or stresses in the edge areas or bulk of the substrate.

[0003] DE 10 2018 005 218 A1 relates to a method for modifying materials, in which the focus of a laser beam is guided relative to a solid object so that, in addition to a two-dimensional motion component, the path also has a motion component perpendicular thereto. In selective laser etching, high-intensity laser radiation leads to localized, crack-free modification of the irradiated material.

[0004] DE 10 2013 10 3 370 A1 describes a method for introducing a perforation into a glass substrate. In this case, an opening is first formed in the glass substrate by laser radiation, and then the material is removed by an etching method.

[0005] Furthermore, DE 10 2018 100 299 A1 discloses a method in which a glass element is exposed to an etching medium which removes the glass of the glass element in an alkaline etching solution at a slow removal rate of less than 8 μm / hour, and the hairline cracks widen to form channels and introduce rounded, essentially hemispherical depressions into the channel walls.

[0006] A disadvantage of the known method is that it is very difficult to produce complex, filamentous structures on 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. Furthermore, the processing time of the method also leaves room for improvement. Summary of the Invention

[0007] The inventors have solved this problem. The object of the present invention is to provide a nearly water-free alkaline etchant that is fast and allows for low-cost glass processing or structuring. This object has been surprisingly achieved according to the present invention.

[0008] 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 carried out by etching, and wherein an alkaline etching medium in an organic solvent is used.

[0009] In particular, the glass material is removed from the glass element selectively or locally, or uniformly, isotropically over the entire surface of the glass element.

[0010] Furthermore, preferably no further additives are used. The organic solvent is present as the main component of the etching, in particular in an amount of more than 30% by weight (wt%).

[0011] Currently, etching is carried out in a water-based alkaline etching medium. However, the boiling point in a specific organic solvent is much higher than in a water-based alkaline etching medium. Thus, etching in an organic solvent can be carried out at higher temperatures and, thus, at higher speed. Furthermore, some glasses which are difficult to structure in a water-based etching medium can be more easily structured in an organic solvent, because of the different way of dissolving degradation products.

[0012] Thus, the etching medium contains almost no water. By water-free etching medium is meant that the water content of the etching medium is preferably less than 5% by weight (wt%), more preferably less than 1% by weight (wt%). This is mainly due to the environmental humidity, which unfortunately cannot be completely avoided. In fact, the solution should be water-free. In contrast to aqueous etching, different properties are used in the current water-free process, for example, an elevated boiling point and a changed solubility.

[0013] In particular, those organic compounds are suitable for dissolving the alkaline agent which have at least one hydroxyl group. Preferably, polyhydric alcohols or organic compounds having at least two hydroxyl groups, respectively, are used.

[0014] The organic solvent preferably comprises an alcohol. The alcohol can in particular be a polyhydric alcohol, or a polyhydroxy alcohol, respectively, in order to increase the solubility of the hydroxide. Particularly suitable are diols or glycols, respectively, such as ethylene glycol. As an example of a suitable solvent or solvent component is glycerol, which is a triol.

[0015] Furthermore, the organic solvent can be a mixture of organic compounds, for example a mixture of polyhydric alcohols, i.e. polyhydroxy alcohols, or a mixture of a polyhydric alcohol with one or more other organic compounds.

[0016] The boiling point of ethylene glycol is approximately 197°C. Thus, its maximum processing temperature is much higher than in a water-based etching medium. Because certain glasses cannot be etched in a water-based etching medium due to the presence of insoluble degradation products, but can be processed in an alcohol, the processing or structuring of other glasses can also be carried out.

[0017] Further, since the maximum etching temperature in organic solvents is much higher than the maximum etching temperature in water-based solvents, it is preferred to carry out the etching at temperatures greater than 130 °C, preferably greater than 150 °C, particularly preferably greater than 170 °C. Thus, the processing speed can be higher.

[0018] Sodium hydroxide (NaOH) or potassium hydroxide (KOH) are particularly suitable as alkaline etching media. Here, KOH is preferred as the alkaline etching medium. KOH is particularly suitable for use as an etching medium for fine structures.

[0019] It has proven particularly preferred that the concentration of KOH in the organic solvent, in particular ethylene glycol, 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.

[0020] It is the object of the present application to provide a fast, almost water-free etching. Thus, 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 pm per hour, preferably greater than or equal to 20 pm per hour.

[0021] The glass element according to the present application is preferably a thin glass in the form of a disc or a plate having two opposing side surfaces. The thickness of the glass element can be less than 1500 micrometers (pm) or have a thickness of 8 mm, 10 mm or 20 mm to 100 mm. Thus, the glass is suitable for processing fine structures or cutouts or for producing an outer contour and for removing glass from a glass element having an initial thickness to a lower target thickness. The thin glass and the high temperature accelerate this process and save or reduce time. Thus, the present application provides a glass element, preferably a borosilicate glass or a soda-lime silicate glass, which can be produced at the Schott AG in Mainz, Germany or is commercially available.

[0022] The present application also comprises a glass element, preferably the glass element comprises one of the following glass compositions in weight percent (wt-%):

[0023]

[0024] (an example of a glass with the above given composition is glass D263 manufactured by the Schott AG in Mainz, Germany);

[0025] or

[0026]

[0027]

[0028] (an example of a glass with the above given composition is glass AF32 manufactured by Schott AG, Mainz, Germany);

[0029] or

[0030]

[0031] (an example of a glass with the above given composition is glass Boro33 manufactured by Schott AG, Mainz, Germany); or

[0032]

[0033] (an example of a glass with the above given composition is glass B270 manufactured by Schott AG, Mainz, Germany).

[0034] Generally, according to the present application, borosilicate glasses or soda-lime silicate glasses with a titanium content are particularly suitable for processing or structuring in an alkaline etching medium of an organic solvent. Titanium compounds are generally poorly soluble in water or completely insoluble in water, like titanium carbide and titanium dioxide. In contrast thereto, titanium compounds are generally highly soluble in organic solvents. Thus, glass elements containing titanium compounds do not form undesirable solid precipitates in organic solvents.

[0035] Further, silicate glasses with a low alkali metal content are particularly suitable for processing or structuring according to the present application. A too high alkali metal content makes etching more difficult. This makes the glass particularly suitable for controlled etching using an alkaline etching medium. According to one refinement of the present application, the glass of the glass element is a silicate glass with an alkali metal oxide content of less than 17% by weight.

[0036] The method according to the present application can provide a glass element, which is pre-damaged using a laser beam of an ultrashort pulse laser by introducing a flaw, and wherein the flaw is expanded by means of the alkaline etching medium. The term "flaw" is understood hereinafter as a material modification, a slit or a very thin channel, which can or can not pass through the substrate.

[0037] The glass element can be pre-damaged using a laser beam by introducing a filamentous flaw, and wherein the filamentous flaw is expanded by the alkaline etching medium to form a channel.

[0038] The filamentous flaw can be a continuous, thin open channel. However, there can also only be a filamentous or linear change in the material. Mixed forms are also possible, in which a cavity or material change extends along a line. For example, one form is a short flaw arranged in a chain along a line, which is caused by periodic self-focusing of a strong laser beam.

[0039] According to the present invention, the filigree cracks are formed by means of a laser beam of an ultrashort pulse laser. The filigree cracks are then expanded or widened by a selective etching process preferably using an alkaline etching medium in an organic solvent to form channels.

[0040] One suitable laser for this purpose is an Nd:YAG laser, for example, emitting at a wavelength of 1064 nm. According to one embodiment, the ultrashort pulse laser is operated at a repetition rate in the range of 10 kHz to 400 kHz, preferably in the range of 30 kHz to 200 kHz. The repetition rate and the scanning speed of the laser beam on the glass element can be selected so that the lateral distance (i.e., the spacing) between adjacent cracks is adjustable. The pulse duration is less than 100 picoseconds, preferably less than 20 picoseconds. Suitable average power of the laser is in the range of 50 W to 500 W.

[0041] Another suitable laser for this purpose is a Yb:YAG laser, for example, emitting at a wavelength of 1030 nm or 513 nm. According to this embodiment, the ultrashort pulse laser operates at a repetition rate in the range of 10 Hz to 50 MHz, preferably 20 Hz to 40 MHz. The pulse duration is less than 20 picoseconds, preferably less than 10 picoseconds and down to 0.5 picoseconds. Suitable average powers of the laser range from 20 W to 500 W.

[0042] In other embodiments, the laser may operate in the wavelength range of 1100 nm to 100 nm (UV) with a pulse duration of 100 ps to 200 fs.

[0043] The method according to the invention specifically comprises the following steps: increasing the diameter of adjacent channels along a predetermined path using an alkaline etching medium until the glass between the channels is removed, the channels coalesce, and the glass element is separated along the path. This method can form the outer contour of the glass element as well as the cutout. As with any wet chemical etching process, the edges of the glass element may be slightly coalesced.

[0044] According to the invention, even hairline cracks with a diameter of not more than 1 μm, preferably not more than 0.8 μm, particularly preferably not more than 0.5 μm can be widened by the etching medium. As a result of the widening, channels are formed in the glass element.

[0045] In a particular embodiment of this process, the predetermined path of the channel forms a closed, for example, 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 is open toward one side of the substrate, i.e., toward the side surface, and thus defines a cutout in the surface of the substrate. The opening can have various geometries or more complex structures.

[0046] 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 taper angle at one edge or wall of the channel with respect to the respective side face. However, channels or edges can be formed with a smaller taper angle or a vanishing taper angle, which means that the angle between the side face and the channel wall or edge is 90° or at least very close to 90°. BRIEF DESCRIPTION OF DRAWINGS

[0047] The application will be explained in more detail below on the basis of preferred embodiments and with reference to the drawings. In each case, identical reference signs in the drawings represent identical or corresponding elements.

[0048] Figure 1 An apparatus for laser working of a glass element is shown as preparation for subsequent etching;

[0049] Figure 2 A glass element with introduced filamentary cracks is shown in a top view;

[0050] Figure 3 A glass element with channels introduced along the filamentary cracks is shown;

[0051] Figure 4 A glass element is shown in which the channels are increased due to etching and join at the side faces;

[0052] Figure 5 A glass element after partial separation is shown;

[0053] Figure 6 The etching rate of glass Boro33 in aqueous KOH or KOH glycol solution as a function of the KOH concentration at different temperatures is shown;

[0054] Figure 7 The solubility of titanium in various etching media is shown;

[0055] Figure 8 A variant of the apparatus shown is shown for introducing a series of cracks or defects inside a glass element; Figure 1 A variant of the apparatus shown is shown for introducing a series of cracks or defects inside a glass element;

[0056] Figure 9 A glass element processed using the apparatus shown after subsequent etching is shown; Figure 8 A glass element processed using the apparatus shown after subsequent etching is shown;

[0057] Figure 10 An embodiment of an apparatus for locally etching a glass element is shown. DETAILED DESCRIPTION

[0058] Figure 1A working example of a laser machining device 20 is shown, by which filamentary cracks 32 can be introduced into a glass element 1 for the purpose of introducing channels 5 at the location of the filamentary cracks 32 in a subsequent etching process. The laser machining device 20 comprises an ultrashort pulse laser 30 with a pre-focusing optics 23 and a positioning device 17. The positioning device 17 enables the impact point 73 of the laser beam 27 of the ultrashort pulse laser 30 to be positioned laterally on one side face 2 of the plate-like glass element 1 to be machined. In the example shown, the positioning device 17 comprises an x-y table on which the other side face 3 of the glass element 1 rests. Alternatively or additionally, however, it is also possible for the optics to be moved in order to move the laser beam 27 and thus the impact point 73 of the laser beam 27 while the glass element 1 remains stationary. The focusing optics 23 then focuses the laser beam 27 to form a focal point which is elongate in the direction of the beam, i.e. correspondingly laterally, in particular perpendicularly, to the side face 2 being irradiated. Such a focal point can be generated, for example, by means of a conical lens (so-called axicon) or a lens with a large spherical aberration. The control of the positioning device 17 and the ultrashort pulse laser 30 is preferably carried out by means of a programmed computer 15. In this way, a predetermined pattern of filamentary cracks 32 distributed laterally along the side face 2 can be generated, in particular by inputting position data, preferably from a file or via a network.

[0059] According to one working example, the following parameters of the laser beam 27 can be used: a laser beam wavelength of 1064 nm, typically for a Nd:YAG laser. The laser beam 27 is generated with an initial beam diameter of 12 mm and is then focused by an optics in the form of a double convex lens with a focal length of 16 mm. The pulse duration of the ultrashort pulse laser is less than 20 ps, preferably approximately 10 ps. The pulses are delivered in pulse trains of 2 or more, preferably 4 or more pulses. The pulse train frequency is 12-48 nm, preferably approximately 20 nm, and the pulse energy is at least 200 microjoules, and correspondingly the pulse train energy is at least 400 microjoules.

[0060] Subsequently, after the introduction of one or in particular more than one filamentary crack 32, the glass element 1 is removed and placed in an alkaline etching medium. In the etching process, glass is removed in the alkaline etching medium along the filamentary cracks 32, thereby introducing channels 5 into the glass element 1 at the location of such cracks 32.

[0061] Etching is carried out using an alkaline etching medium in an organic solvent.

[0062] Preferably, a KOH solution in an organic solvent, preferably ethylene glycol, is used as the alkaline etching bath, the concentration of KOH in the organic solvent being 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 application, the etching is carried out at a temperature of greater than 130°C, preferably greater than 150°C, particularly preferably greater than 170°C.

[0063] Figure 2 The glass element 1 is shown in a top view of the side 2, which has a plurality of filament-like cracks 32, which can be inscribed in the glass element 1 in a specific pattern by the above-described computer-controlled actuation of the positioning device 17 and the ultra-short pulse laser 30. In particular, as an example, the filament-like 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 can also be slightly rounded. It will be apparent to the person skilled in the art that, by this machining, not only a rectangular path, but also any shaped path or line can be formed.

[0064] Figure 3 The glass element 1 is shown after the subsequent etching step, in which the filament-like cracks are expanded by the alkaline etching medium and form channels 5 which are arranged next to one another along the predetermined path and in a row along the path. The diameter of the channels 5 is increased by the alkaline etching medium until the glass between the channels 5 is removed, and the channels 5 can join and the glass element 1 can be separated along the path. For example, according to Figure 3 The predetermined path of the channels 5 shown forms a closed rectangular path, so that the separation of the glass element by the alkaline etching medium along the path results in an opening in the glass element. Of course, the predetermined path can also be of other shapes, such as circular or annular.

[0065] Figure 4 The glass element 1 is shown in which the channels 5 join due to the etching. An embodiment of the application is based on increasing the diameter of the channels 5 by etching until the glass between the channels 5 is removed and the channels 5 join.

[0066] Figure 5 The glass element 1 is shown after separation along the path. Since the channels 5 are arranged along a rectangular, closed separation line, the inner portion is detached and an opening 13 is formed in the glass element 1. The glass element 1 is indicated with a hatched area around the glass element 1, so that the element and the opening 13, for example the channels 5 in the drawing, are distinguished from one another, respectively, the inner portion.

[0067] Figure 2 to Figure 5 An example of an embodiment of the method of the application is shown, in which:

[0068] - the impact points 73 of the laser beam 27 are conveyed along a predetermined path on the glass element 1;

[0069] - introducing a plurality of hairline cracks 32 adjacent to one another along a path into the glass element 1;

[0070] - expanding the filigree cracks 32 by means of an alkaline etching medium in an organic solvent to form channels 5; and - wherein the diameters of the channels 5 arranged adjacent to each other along a predetermined path are increased by the alkaline etching medium until the glass between the channels 5 is removed and the channels 5 are joined, and the glass element 1 can be separated along this path.

[0071] The channel 5 generally has a tubular cylindrical basic shape or is a tube with cylindrical walls. Here, there may be a slight taper from the opening 13 at the side 2 to the middle of the glass element 1. When the generally cylindrical channel 5 is joined during the widening process during the etching operation, a ridge 52 is formed at the adjacent location. In general, not limited to Figure 4 By way of example, one embodiment of the invention provides that the channels 5 abut one another, thereby forming 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 parallel to the longitudinal direction of the channels 5, and thus Figure 4 Only sawtooth-like or tooth-like elements can be seen in the description at the location of the transition areas between adjacent channels 5. However, if etching is continued, the ridges will flatten out and may no longer be visible.

[0072] 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 taper angle at one edge 10 or wall of the channel 5 relative to the respective side 2 , 3 .

[0073] At higher removal rates in the range of at least 10 μm / hour, approximately 15 μm / hour to preferably equal to or greater than 20 μm / hour, fairly vertical cavities still exist, thereby resulting in cone angles in the range of 90°+ / -5°, preferably 90°+ / -3°, particularly preferably 90°+ / -1°.

[0074] One object of the present invention is to provide a fast, virtually water-free etchant. Thus, if the glass element is exposed to an alkaline etching medium in an organic solvent at an etching temperature of 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.

[0075] Because many organic solvents, such as alcohols and particularly ethylene glycol, have higher boiling points than water-based alkaline etching media, etching in organic solvents can be performed at higher temperatures and, therefore, at higher speeds.

[0076] Figure 6The etching rate measurements of Schott AG's Boro33 borosilicate glass, having the composition given above and a thickness of 1300 μm, are shown for different KOH aqueous solution concentrations at different temperatures. These measurement results at 70°C, 100°C, 120°C, and 140°C are compared with the etching rates of 6 mol / l KOH ethylene glycol (EG) solutions at 140°C and 175°C.

[0077] The boiling point of a 6 mol / l KOH aqueous solution is about 115° C., the boiling point of a 15 mol / l KOH aqueous solution is about 140° C., and the boiling point of a 6 mol / l KOH ethylene glycol (EG) solution is about 195° C. Therefore, the etching temperature is limited by the boiling point of the solvent.

[0078] like Figure 6 As shown in Figure 1, the etching rate in a 6 mol / l KOH glycol solution at 140°C reaches 4 μm per hour. This etching rate is higher than all water-based etching solutions with the same KOH molar concentration. However, an etching rate of 21 μm per hour has been measured for a 6 mol / l KOH glycol solution at 175°C. This etching rate is an order of magnitude higher than that achievable with aqueous KOH solutions. Furthermore, for borosilicate glass D263 from Schott AG in Mainz, Germany, with the aforementioned composition, an etching rate of nearly 14 μm was achieved at 175°C using a 6 mol / l KOH glycol solution.

[0079] In comparison, it has been measured that the etching rate of a 6 mol / l KOH aqueous solution at about 100°C is less than 4 μm per hour, and the etching rate of a 15 mol / l KOH aqueous solution at about 120°C is less than 10 μm per hour. The etching rate of a 6 mol / l KOH ethylene glycol solution is even much greater than the etching rate of a water-based KOH solution at high temperature and high KOH molar concentration, as can be seen from the measured etching rate of an 18 mol / l solution at 140°C.

[0080] The solubility of degradation products produced during etching in water often varies greatly. Some glasses are difficult to structure in water-based etching media because low-solubility components can 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 with organic solvents. Consequently, glass components containing titanium compounds in organic solvents do not form undesirable solid precipitation products. Consequently, glass components containing titanium have a positive impact on processing time.

[0081] Figure 7The bar graphs show examples of titanium solubility. Specifically, the solubility of etching solutions consisting of 3 mol / l aqueous KOH (left column) and 6 mol / l aqueous KOH (center column) is compared to the solubility of an etching solution consisting of 6 mol / l KOH in ethylene glycol. As can be seen from the bar graphs, the solubility in organic solvents is almost 10 times higher than that of the equivalent water-based solution containing 6 mol / l KOH, and over 20 times higher than that of the 3 mol / l aqueous KOH solution.

[0082] The present disclosure is not limited to ethylene glycol as a solvent, which is only used for the exemplary embodiments discussed with reference to the accompanying figures. For example, other polyvalent organic compounds, preferably having a high boiling point, may also be used. Various organic compounds may be mixed to adjust the characteristics 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.

[0083] Figure 8 Shown Figure 1 A variation of the apparatus shown is used to introduce a series of localized or punctate cracks within a glass element 1. For example, rather than forming straight, elongated, thread-like lines, a very small focal point is moved along a random path through the material, producing a small modification at each focal point. The movement of the focal point through the material forms a modification curve that contacts the surface at a certain point. The modified structure is then selectively etched, creating a 3D structure in the material. Thus, focusing optics 23 of a laser beam 27 from an ultrashort pulse laser 30 can be directed into the bulk of the glass element 1 using a scanning motion along one side 2. To modify the material, the path of the localized or punctate cracks 33 is written into the bulk of the glass element 1 using laser beam 27. The focal point of laser beam 27 can be guided relative to the bulk so that the path has a two-dimensional motion component as well as a perpendicular motion component. This laser-induced modification can shorten the etching rate in subsequent wet-chemical processes. Thanks to the nearly water-free selective alkaline etching, 3D structures or objects can be created from a block in this manner, either in the form of undercuts or curves.

[0084] Figure 9 shows that after subsequent etching, the Figure 8 The device shown processes a glass element 1 in which a previous local or point-shaped crack 33 in the interior of the glass element 1 is expanded by, for example, an alkaline etching medium 4 to form a channel 5 .

[0085] Figure 10An embodiment of an apparatus for locally etching a glass element is shown. An electrode 35 is immersed in a vessel 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 in the side 2 of the glass element 1. Of course, another local heating element can be used instead of the electrode 35 to locally etch the glass element 1 in the almost water-free alkaline etching medium 4. Thus, the precise chemical etching of the above-mentioned glass composition is accelerated by the heat treatment. And no intermediate or post-treatment is required. Micro-holes of a few millimeters in depth can be drilled in a few seconds, and channels of a few hundred micrometers in depth can be manufactured without any difficulty. Glass of a few millimeters in thickness can also be removed.

[0086] List of reference signs:

[0087]

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 of an ultrashort pulse laser; and expanding the crack in the glass element by etching using the alkaline etching medium in the organic solvent to form a channel, wherein the diameter of the channels arranged adjacent to each other along the predetermined path is increased by the alkaline etching medium until glass between the channels is removed and the channels are combined, and the glass element is thereby separated along the path, wherein the alkaline etching medium has a water content of less than 5% by weight (wt%) and the organic solvent comprises an alcohol.

2. The method according to claim 1, wherein The glass material is removed from the glass element (1) selectively or locally, or is removed uniformly and isotropically over 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% by weight (wt%).

4. The method according to claim 1 or 2, wherein: The organic solvent includes a polyhydric alcohol.

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.

7. The method according to claim 6, wherein: The concentration of KOH is greater than 4 mol / l but less than 30 mol / l.

8. The method according to claim 6, wherein: The concentration of KOH is greater than 5 mol / l but less than 30 mol / l.

9. The method according to claim 6, wherein: The concentration of KOH is greater than 6 mol / l but less than 30 mol / l.

10. The method according to claim 1 or 2, wherein: The etching is performed at a temperature greater than 130°C.

11. The method according to claim 1 or 2, wherein: The etching is performed at a temperature greater than 150°C.

12. The method according to claim 1 or 2, wherein: The etching is performed at a temperature greater than 170°C.

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

14. The method according to claim 1 or 2, wherein: The glass element (1) is exposed to the alkaline etching medium (4), which removes material from the glass element (1) at a removal or etching rate of at least 10 μm per hour.

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

16. The method according to claim 1 or 2, wherein: The glass element (1) is borosilicate glass or soda-lime silicate glass.

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

18. The method according to claim 1 or 2, wherein: The glass element (1) has one of the following glass components, expressed in weight percentage: 。 19. The method according to claim 1 or 2, wherein: The predetermined path of the channel forms a closed circular or rectangular path, so that separation of the alkaline etching medium (4) along the path results in openings 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 taper angle at one edge (10) of the channel relative to the corresponding side (2, 3).

20. The method according to claim 1 or 2, wherein: The organic solvent includes a glycol.

21. The method according to claim 1 or 2, wherein The organic solvent includes ethylene glycol.

22. 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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