Method and system for substrate etching, and substrate holder

Abstract

The present invention relates to a method (100) and to a system (1) for substrate etching, and to a substrate holder (30). A substrate blank (2) is arranged (S2) in the substrate holder (30) and a substrate blank surface (4) is treated (S3) with an etching medium (41). According to the invention, prior to treatment with the etching medium (41), the substrate blank (2) is irradiated (S1) with laser radiation (3) along an outer contour (6) of a target substrate (5), and therefore during treatment with the etching medium (41), the target substrate (5) is separated from the substrate blank (2).

Description

[0001] Method and system for substrate etching and substrate holder

[0002] The present invention relates to a method and a system for substrate etching and a substrate holder.

[0003] Etching processes are known for producing substrates with desired surface properties and / or for modifying substrate dimensions, particularly thickness. Typically, a variety of substrates, for example, made of glass

[0004] (SiO2) , fixed in a substrate holder (carrier) and then exposed to an acidic and / or alkaline etching medium.

[0005] A problem with such etching processes is the etch marks that commonly occur. These etch marks, also known as ablations, are created by securing the substrates in the substrate holder. Obtaining substrates free of etch marks requires complex post-treatment steps such as trimming or grinding the etched substrates.

[0006] It is an object of the present invention to improve the etching of substrates, in particular to enable efficient production of substrates without etching marks.

[0007] This object is achieved by a method and a system for substrate etching as well as a substrate holder according to the independent claims.

[0008] Preferred embodiments of the invention are the subject of the dependent claims and the following description. In a method for substrate etching according to a first aspect of the invention, a substrate blank is arranged in a substrate holder and a substrate blank surface is treated with an etching medium. According to the invention, the substrate blank is irradiated with laser radiation along an outer contour of a target substrate before treatment with the etching medium, so that the target substrate detaches itself from the substrate blank during treatment with the etching medium, in particular automatically.

[0009] One aspect of the invention is based on the approach of pretreating a substrate blank with the aid of laser radiation in such a way that the etching effect of an etching medium on the substrate blank is intensified or accelerated in one or more predetermined regions on the substrate blank surface. The substrate blank is expediently irradiated in such a way that a piece of the substrate blank which corresponds to a target substrate is or can be etched out during the etching treatment. Such etching-induced removal of the target substrate from the substrate blank enables the substrate blank to be fixed in a substrate holder without the target substrate being shadowed. In other words, the substrate blank can be arranged in the substrate holder in such a way that a region of the substrate blank which corresponds to the later removed target substrate is not contacted by the substrate holder.

[0010] Preferably, the laser radiation is irradiated along an outer contour of the target substrate onto the substrate blank. For example, areas on the substrate blank surface can be irradiated that lie on the desired outer contour of the target substrate or that together image the outer contour in a discrete manner. It has been shown that molecular bonds in the substrate material can be weakened or broken with the aid of laser irradiation. This can make it easier for the etching medium to dissolve substrate material or components thereof in these areas. The strength of the modification of the substrate material - and thus the (local) etching effect of the etching medium - can be achieved with little effort, for example, by appropriate selection of laser parameters such as wavelength, power or pulse energy, pulse duration, focus position and / or the like.

[0011] It is advisable to position the substrate blank in the substrate holder in such a way that the area enclosed by the outer contour is not contacted by the substrate holder. This allows etch marks on the target substrate to be reliably and easily avoided.

[0012] Preferably, the substrate blank remains arranged in the substrate holder until the target substrate is removed from the substrate blank. It is expedient for the etching treatment to be terminated immediately after the target substrate has been removed. This prevents the target substrate from coming into prolonged contact with the substrate holder within the etching medium, which could result in etch marks on the target substrate.

[0013] Preferred embodiments of the invention and further developments thereof are described below, which, unless expressly excluded, can be combined with one another as desired and with the aspects of the invention described below.

[0014] In a preferred embodiment, the substrate blank is irradiated with laser radiation before being arranged in the substrate holder. This can facilitate the irradiation of the substrate blank and / or increase the precision during irradiation. In a further preferred embodiment, the substrate blank is irradiated with laser radiation along the outer contour of the target substrate in such a way that, when the substrate blank is treated with the etching medium, through-holes are created in the substrate blank along the outer contour of the target substrate. In other words, the substrate blank can be irradiated in such a way that, during etching, through-holes are formed in the substrate blank which are arranged, in particular lined up, along the outer contour. Expediently, the substrate blank is irradiated with laser pulses for this purpose. This is also advantageous because it allows a particularly high energy input per unit of time to be achieved.

[0015] During the etching treatment, the through-holes can continue to develop. In particular, the through-holes can grow, i.e., their diameter can increase. The etching treatment expediently continues until adjacent through-holes connect with one another, i.e., the material layer between two through-holes is essentially completely etched away, and the target substrate is thereby released from the substrate blank. The creation of through-holes, in particular through-holes that grow larger, during etching allows for a particularly reliable and gentle removal of the target substrate.

[0016] In a further preferred embodiment, the substrate blank is irradiated with laser radiation along the outer contour of the target substrate in such a way that, during treatment of the substrate blank with the etching medium, through-holes are created in the substrate blank along the outer contour of the target substrate at a predetermined distance from one another. Adjacent through-holes expediently connect with one another after a predetermined treatment time of the substrate blank with the etching medium. By selecting the distance between adjacent points of incidence, in the area of ​​which the laser radiation strikes the substrate blank surface and the through-holes are created during etching, the desired treatment time can be determined particularly easily.

[0017] In a further preferred embodiment, the target substrate is removed from the substrate blank without etching marks, in particular substantially without etching marks. The substrate blank can be held in such a way—for example, with the aid of a suitably designed substrate holder—and / or the substrate blank surface can be irradiated and / or treated with the etching medium in such a way that the target substrate is removed from the substrate blank without etching marks. This eliminates the need for post-treatment aimed at removing such etching marks.

[0018] Preferably, the treatment duration is matched to the speed of an etching process on unirradiated sections of the substrate blank surface. In particular, the treatment duration can be adapted to a desired intensity of the etching treatment of the substrate blank surface in unirradiated sections. This makes it possible to remove the target substrate from the substrate blank at a time at which the etching process on the unirradiated substrate blank surface is also completed. In other words, it is thus possible to essentially synchronize the removal of the target substrate and the completion of the "conventional" etching process, for example for surface modification.

[0019] In a further preferred embodiment, the substrate holder is placed in an etching medium bath for treating the substrate blank surface with the etching medium. The substrate holder is expediently removed from the etching medium bath immediately after the target substrate has been detached from the substrate blank. For example, the substrate holder can be removed from the etching medium bath immediately after the predetermined treatment time has been reached. This prevents the surface of the target substrate from being etched more deeply than desired and / or etching marks from forming on the detached target substrate that may now be in contact with the substrate holder.

[0020] In a further preferred embodiment, the detached target substrate is caught by the substrate holder. The substrate holder expediently has a collecting device for this purpose. For example, the substrate holder can have one or more collecting elements positioned next to and / or below the substrate blank arranged in the substrate holder. These collecting elements can be designed, for example, as pins. The target substrate can thus fall out of the substrate blank after being detached, being securely caught and guided by the collecting elements.

[0021] In a further preferred embodiment, the substrate blank is held by its arrangement in the substrate holder such that, when the substrate holder is aligned horizontally, the substrate blank surface is inclined relative to the vertical. In other words, the substrate blank is held at an angle in the substrate holder so that the target substrate can fall out of the substrate blank after removal. Such an arrangement of the substrate blank in the substrate holder can significantly facilitate removal. In particular, it can be ensured that removal occurs automatically and in a directed manner. This can increase process efficiency.In a further preferred embodiment, the substrate blank surface is inclined relative to the vertical by an angle of between 0° and 90° inclusive, preferably between 10° and 90° inclusive, due to the arrangement of the substrate blank in the substrate holder with its horizontal orientation. Tests have shown that this enables particularly reliable removal of the target substrate from the substrate blank. In particular, with an inclination of 10° or more, tilting of the target substrate on the remaining substrate blank, i.e., the remaining "frame," can be reliably avoided, or the risk of such tilting can at least be reduced.

[0022] In a further preferred embodiment, the laser radiation is irradiated in such a way that the target substrate is released from the substrate blank after a predetermined treatment time with the etching medium. The predetermined treatment time is expediently selected to be shorter than or substantially equal to a time period necessary for a desired etching effect on the substrate blank surface in an unirradiated section. This ensures that the target substrate is released from the substrate blank at the end of the desired etching process, for example, for surface modification.

[0023] In a further preferred embodiment, the substrate blank is irradiated with laser radiation on only one side, essentially perpendicular to the substrate blank surface. The penetration depth of the laser radiation into the substrate blank, and thus possibly also the depth to which modification of the substrate material takes place with regard to an effect by the etching medium, can be adjusted by selecting the laser parameters. Irradiation of the substrate blank on only one side can accelerate the process and / or reduce the effort required for laser irradiation.

[0024] In a further preferred embodiment, the substrate blank is irradiated with laser radiation on two opposite sides substantially perpendicular to the substrate blank surface. Here, too, the penetration depth of the laser radiation can be adjusted on both sides, optionally independently of each other. Irradiation of the substrate blank on both sides enables targeted etching along the outer contour on both the front and back sides of the substrate blank and thus faster removal of the target substrate during treatment with the etching medium.

[0025] In a further preferred embodiment, the irradiation is carried out on the two opposite sides using different laser parameters. For example, the laser parameters can be selected such that the penetration depth of the laser radiation on one side is greater than the penetration depth of the laser radiation on the opposite side of the substrate blank. This can be used to influence the treatment time with the etching medium required to trigger the target substrate. In particular, it is thereby possible to control the required treatment time. For example, the required treatment time can be shortened by having the etching process take place on both sides of the substrate.

[0026] In a further preferred embodiment, during the irradiation of the substrate blank with laser radiation along the outer contour of the target substrate, laser pulses impinge on the substrate blank surface at least in sections in the region of regularly spaced impact points. The spacing can be selected depending on the material. The spacing between adjacent impact points can be, for example, 1 pm to 15 pm, preferably 2 pm to 10 pm, in particular 3 pm to

[0027] 5 pm. It is advisable for the impact points to lie on a straight line, at least in some sections. This allows for uniform etching along the outer contour.

[0028] In principle, however, other, possibly even irregular, arrangements of the impact points are also conceivable. For example, the impact points can also run along a curved line in sections. The arrangement of the impact points can depend, in particular, on the substrate material and / or the geometric requirements.

[0029] In a further preferred embodiment, during irradiation of the substrate blank with laser radiation, laser pulses impinge on the substrate blank surface along the outer contour of the target substrate in the region of impact points, preferably at least partially regularly spaced. The impact points expediently lie, at least partially, on two or more mutually parallel lines. Such irradiation of the substrate blank allows the modification of the substrate material with regard to the effect of the etching medium over a larger area around the region corresponding to the target substrate. In particular, the effect of the etching medium can thus be enhanced or accelerated along a wide "band" around the target substrate. During the etching treatment, a wider gap can thus be created between the target substrate and the remaining substrate blank.This is particularly advantageous with a thick substrate blank, as it prevents the target substrate from becoming jammed during removal, or at least reduces the risk of jamming. Furthermore, it can also influence the treatment time required to completely remove the target substrate.

[0030] In a further preferred embodiment, the substrate surface is treated with an etching medium containing an alkaline compound, for example potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH), sodium hydroxide (NaOH), and / or lithium hydroxide (LiOH). This allows the target substrate to be dissolved out particularly reliably. In particular, such an etching medium can enable particularly controlled etching—and thus controlled dissolution of the target substrate.

[0031] In a further preferred embodiment, the substrate blank surface is treated with the etching medium at a temperature of 90°C or more, preferably 110°C or more, in particular 120°C or more. The substrate blank surface is particularly preferably treated with the etching medium at approximately 120°C. For this purpose, for example, an etching medium bath can be brought to such a temperature and the substrate blank can be immersed in the etching medium bath. At such a temperature, the etching medium can act on the irradiated areas on the substrate blank surface in a reliable and controlled manner. By selecting a high temperature for the etching medium, for example 110°C or even 120°C, the etching process can be accelerated if necessary, in particular compared to conventional etching processes.

[0032] It may be advantageous to treat the substrate blank surface with the etching medium at a temperature between 90 °C and 190 °C, preferably between 110 °C and 170 °C, especially between 120 °C and 150 °C. Working within these temperature ranges can prevent excessive evaporation of the etching medium. Furthermore, heating the etching medium to an even greater degree is disproportionately energy-intensive compared to achieving an improved etching effect.

[0033] The temperature range chosen may depend on the application or substrate. Conventional display glasses, for example, can be etched well at around 120 °C. However, certain ceramic glasses, where the etching process is slower, may require correspondingly higher temperatures.

[0034] A system for substrate etching, in particular for carrying out a method according to the first aspect of the invention, according to a second aspect of the invention has a laser device which is set up to irradiate a substrate blank with laser radiation along an outer contour of a target substrate such that the target substrate is released from the substrate blank, in particular automatically, when treated with an etching medium. The system also expediently comprises a substrate holder in which the substrate blank can be arranged, and an etching device which is set up to treat the irradiated substrate blank arranged in the substrate holder with the etching medium. With such a system, substrates can be produced, for example, with desired surface properties obtained by etching and which do not bear any etching marks.

[0035] The laser device can, for example, have one or more solid-state lasers, for example fiber lasers. The laser device is expediently configured to repeatedly generate one or more laser pulses synchronously. The laser device is preferably further configured to change the position of the region in which the one or more synchronously generated laser pulses impinge on the substrate blank surface, so that the outer contour of the target substrate can be "scanned". For this purpose, for example, at least part of an optics of the laser device can be mounted displaceably relative to the target substrate or can be configured to influence the propagation direction of the laser radiation.

[0036] The etching device expediently has an etching medium bath into which the substrate holder together with the substrate blank can be introduced.

[0037] A substrate holder for holding substrate blanks, in particular for use in the method according to the first aspect of the invention, according to a third aspect of the invention has a collecting device that is designed to collect a target substrate that has been removed from the substrate blank during treatment of a held substrate blank with an etching medium. With such a substrate holder, the removed target substrate can be safely and reliably removed from the etching medium bath and post-treated, for example, cleaned and / or rinsed and dried.

[0038] The invention is explained in more detail below with reference to figures. Where appropriate, elements with the same effect are provided with the same reference numerals. The invention is not limited to the exemplary embodiments shown in the figures - not even with regard to functional features. The previous description as well as the following description of the figures contain numerous features, some of which are summarized in the dependent claims. However, a person skilled in the art will also consider these features, as well as all other features disclosed above and in the following description of the figures, individually and combine them to form further useful combinations.In particular, all of the features mentioned can be combined individually and in any suitable combination with the method according to the first aspect of the invention, the system according to the second aspect of the invention and the substrate holder according to the third aspect of the invention.

[0039] They show, at least partly schematically:

[0040] Fig. 1 shows an example of a method for substrate etching using a corresponding system;

[0041] Fig. 2 shows an example of a substrate blank irradiated with laser radiation in a plan view;

[0042] Fig. 3 shows an example of the substrate blank irradiated with laser radiation from Fig. 2 in a cross section;

[0043] Fig. 4 shows an example of an etching treatment of a substrate blank with an etching medium; and

[0044] Fig. 5 shows an example of a substrate holder.

[0045] Figure 1 shows an example of a system 1 for performing a method 100 for substrate etching. The system 1 comprises a laser device 20, a substrate holder 30, an etching device 40, and—optionally—a post-treatment device 50.

[0046] In the method 100 that can be carried out with this system 1, a substrate blank 2, such as a glass plate, is irradiated with laser radiation 3 in a method step S 1 . The laser device 20 is expediently used for this purpose. The laser device 20 can comprise any suitable laser, for example a fiber laser, to generate the laser radiation 3. The laser radiation 3 preferably comprises a plurality of laser pulses that successively impinge on a substrate blank surface 4.

[0047] The substrate blank 2 is irradiated with the laser radiation 3, in particular the laser pulses, along an outer contour (see Figure 2) of a target substrate 5. The outer contour is expediently successively "scanned" with the laser radiation 3, in particular the laser pulses. In other words, it is preferred if the laser radiation 3 strikes the substrate blank surface 4, for example, in the region of regularly spaced impact points (see Figure 4), wherein the position of the impact points corresponds to the outer contour. The regions in which the laser radiation 3 strikes the substrate surface 4 can therefore discretely image the outer contour.

[0048] The substrate blank 2 is expediently irradiated with laser radiation 3 in such a way that the target substrate 5 is released from the substrate blank 2 during treatment with an etching medium 41. For this purpose, it may be necessary to adapt laser parameters to properties of the substrate blank 2, for example by configuring the laser device 20. It is conceivable, for example, to adapt laser parameters to the material and / or the thickness of the substrate blank 2. Such laser parameters can relate, for example, to the power, in particular energy per laser pulse, the pulse duration, the distance between the impact points, the wavelength and / or the like.

[0049] By appropriately irradiating the substrate blank 2, the substrate material can be modified along the outer contour, particularly in the area of ​​the impact points of the laser radiation 3, in such a way that the effect of the etching medium 41 is enhanced and / or accelerated. In the case of substrates made of quartz glass (SiO2), for example, the atomic bonds between silicon atoms (Si) and oxygen atoms (O) can be at least partially broken and / or weakened when irradiated at an appropriate frequency, so that the material in this area can be removed much more quickly by a subsequent wet-chemical etching process. In particular, the irradiation can promote the following reactions:

[0050] SiO2+ 2 NaOH -> Na2SiO3+ H20

[0051] SiO2+ 6 HF -> H2SiF6+ 2 H20.

[0052] In a further method step S2, the substrate blank 2 is arranged in the substrate holder 30. For example, the substrate blank 2 can be inserted into the substrate holder 30. For this purpose, the substrate holder 30 can have a holding device, for example in the form of slots (see Figure 5).

[0053] As indicated in Figure 1, the substrate blank 2 is preferably held by the arrangement in the substrate holder 30 such that the substrate blank surface 4 is inclined relative to the vertical when the substrate holder 30 is horizontally aligned. This can facilitate the removal of the target substrate 5 from the substrate blank 2 in a further method step S3.

[0054] In this method step S3, the substrate blank surface 4 is treated with the etching medium 41, expediently using the etching device 40. For this purpose, the etching device 40 can have an etching medium bath containing the etching medium 41. Preferably, the substrate holder 30, together with the substrate blank 2, is immersed in the etching medium bath.

[0055] The etching medium 41 can be an alkaline or acidic liquid. For example, potassium hydroxide (KOH), sodium hydroxide (NaOH), or hydrofluoric acid (HF) can be used to treat glass substrates.

[0056] It is preferred that the substrate blank 2 remains in the etching medium 41 for at least a predetermined treatment period. After this treatment period has elapsed, the etching medium 41 has advantageously dissolved the substrate material along the outer contour, particularly in the region of the impact points of the laser radiation 3, to such an extent that a gap has formed between the target substrate 5 and the remaining substrate blank 2, the so-called "frame." Accordingly, the target substrate 5 can be released from the substrate blank 2.

[0057] Preferably, the detached target substrate 5 is collected by the substrate holder 30 in a further, optional method step S4. For this purpose, the substrate holder 30 can have a collecting device (see Figure 5).

[0058] In a further, optional method step S5, the substrate holder 30, together with the remaining substrate blank 2 and the removed target substrate 5, can be removed from the etching medium 41. The target substrate 5 is then expediently cleaned, for example, by rinsing with a rinsing medium. The target substrate 5 can then be dried.

[0059] The cleaning and / or drying can be carried out using the post-treatment device 50. For this purpose, the post-treatment device 50 expediently comprises a cleaning and drying chamber that can accommodate the substrate holder 30.

[0060] Figure 2 shows a first example of a substrate blank 2 irradiated with laser radiation in a plan view, so that a substrate blank surface 4 is visible.

[0061] The substrate blank 2 was irradiated with laser radiation along an outer contour 6 of a target substrate 5 in such a way that the target substrate 5 can be detached from the substrate blank 2 upon treatment with an etching medium. The outer contour 6 is shown hatched.

[0062] During irradiation, the laser radiation preferably impinges on the substrate blank surface 4 in the region of impact points (see Figure 4). The impact points are preferably arranged in a line-like manner, at least in sections, corresponding to the outer contour 6. Where the laser radiation impinges on the substrate blank surface 4 and modifies the substrate material accordingly, the etching effect of the etching medium is expediently enhanced or accelerated.

[0063] In the example shown, the impact points lie on three different lines 7a, 7b, 7c, which run parallel to one another in sections. Expediently, all impact points lying on the same line 7a, 7b, 7c are evenly spaced from one another. The lines 7a, 7b, 7c are shown as dotted lines, whereby each point can be regarded as an impact point. As shown in Figure 2, the lines 7a, 7b, 7c are preferably arranged in a nested manner, i.e. lying one inside the other. In other words, an outer line 7a and an inner line 7c can be provided. The inner line 7c delimits the (later) target substrate 5, while the position of the outer line 7a relative to it determines the width of a gap created during the etching treatment between the target substrate 5 and the remaining substrate blank 2.In order to enable the gap to be created evenly, it can be provided, depending on the desired width of the gap, for laser radiation to impinge on the substrate blank surface 4 between the outer and inner lines 7a, 7c, as in the present example. The corresponding impact points can, as in the present example, lie on a line 7b or on several further lines. In principle, however, it is also possible to irradiate the substrate blank 2 in such a way that laser radiation impinges on the substrate blank surface 4 only in the region of impact points that lie on only two different lines 7a, 7c or even on only one line 7a.

[0064] Figure 3 shows an example of the substrate blank 2 from Figure 2 irradiated with laser radiation in a cross-section. Various irradiation options are illustrated purely for the purpose of explanation.

[0065] On the one hand, it is possible to irradiate the substrate blank 2 with laser radiation only on one side. This is indicated by the dashed line, which illustrates the penetration depth of laser radiation in the area of ​​impact points located on the inner line 7c delimiting the target substrate 5.

[0066] The term "penetration depth" refers here in particular to a depth or a

[0067] This refers to the depth range in which the laser radiation interacts particularly strongly with the substrate material. In other words, "penetration depth" conveniently refers to the depth or depth range in which the substrate material is modified in such a way that the etching effect of the etching medium is enhanced or accelerated.

[0068] The penetration depth can be adjusted by selecting appropriate laser parameters, for example by adjusting the wavelength, the power or pulse energy, the pulse duration and / or the like, in particular the focus position or focus depth with respect to the substrate blank surface 4.

[0069] On the other hand, it is possible to irradiate the substrate blank 2 on two opposite sides, i.e., both on the front and on the back. Such two-sided irradiation is indicated by the dashed lines, which illustrate the penetration depth of laser radiation in the region of impact points located, on the one hand, on the central line 7b or on the outer line 7a, and, on the other hand, on corresponding, opposite lines 7b', 7a'.

[0070] With bilateral irradiation, it is generally possible to perform symmetrical irradiation (see lines 7b, 7b'). However, it is also conceivable to perform asymmetric irradiation (see lines 7a, 7a'). With such asymmetric irradiation, the penetration depth of the laser radiation on one side can be greater than the penetration depth on the other, opposite side.

[0071] As shown in Figure 3, the various irradiation options can be applied together. However, it is also conceivable to irradiate exclusively on one or both sides, and—in the case of bilateral irradiation—to irradiate exclusively symmetrically or asymmetrically.

[0072] By irradiating along two or more lines 7a, 7b, 7c, which run parallel at least in sections, the treatment time required to release the target substrate can be influenced. In principle, at least up to a certain limit, a faster release of the target substrate from the substrate blank can be achieved with an increasing number of lines—i.e., with a wider gap. Alternatively or additionally, the treatment time can also be influenced by the selected penetration depth(s) of the laser radiation.

[0073] Figure 4 shows an example of an etching treatment of a substrate blank with an etching medium. The substrate blank was irradiated with laser radiation before the etching treatment. As a result, the substrate material in the hatched regions 8, in which the laser radiation strikes a substrate blank surface 4, is expediently modified in such a way that the etching effect of the etching medium is intensified or accelerated. During the etching treatment, substrate material is dissolved to a correspondingly greater extent in the regions 8. In this way, through-holes 9 can form in the substrate blank in the regions 8.

[0074] As the treatment of the substrate blank with the etching medium progresses, the through-holes 9 advantageously grow in size. In other words, the through-holes 9 can increasingly expand. This is indicated in Figure 4 by the dashed circles. Depending on the distance between adjacent impact points, in the region 8 of which the laser radiation strikes the substrate blank surface 4, adjacent through-holes 9 can connect with one another sooner or later. In other words, as the etching treatment progresses, the material layer between adjacent through-holes 9 dissolves essentially completely.

[0075] This mechanism advantageously leads to the formation of a gap between the remaining substrate blank and a target substrate whose outer contour corresponds to the sequence of impact points. Accordingly, the target substrate can detach from the substrate blank.

[0076] In the example of Figure 4, the impact points are arranged regularly on the substrate blank surface 4. In particular, the impact points lie on a dashed line 7 and are spaced a predetermined distance from the adjacent impact points. The regions 8 around the impact points, in which the laser radiation strikes the substrate blank surface 4, are arranged correspondingly regularly, and the through holes 9 are also formed correspondingly regularly.

[0077] The treatment time required to connect the through-holes 9 and the associated removal of the target substrate can be specified in particular by selecting the distance between adjacent impact points or regions 8. In this respect, the treatment time can be tailored to a desired effect of the etching medium on sections of the substrate blank surface 4 that are not irradiated with laser radiation - i.e., are unmodified. In other words, the treatment time can be adjusted by specifying the distance between adjacent impact points or regions 8 such that the target substrate is removed essentially at the same time as the desired etching effect is achieved in unmodified sections of the substrate blank.

[0078] Figure 5 shows an example of a substrate holder 30 in a side view. The substrate holder 30 has a holding device 31 for holding substrate blanks 2 and a collecting device 32 for collecting target substrates 5 dissolved from the substrate blanks 2 during treatment with an etching medium. For reasons of clarity, only one substrate blank 2 and one target substrate 5 are shown.

[0079] The holding device 31 is preferably designed such that held substrate blanks 2 are not contacted in a region which corresponds to the target substrate 5 to be removed. For this purpose, the holding device 31 expediently has a plurality of slots 33 into which the substrate blanks 2 can be inserted. As a result, contact of the substrate holder 30 with the substrate blanks 2 can be limited to a narrow strip at the edge of the substrate blanks 2. For example, the substrate blanks 5 can be inserted into the slots such that contact of the substrate holder (30) with the substrate blanks (2) remains limited to a section which lies outside a region corresponding to the target substrate (5) to be removed. The region corresponding to the target substrate 5 to be removed remains unaffected (cf. Figure 2).For reasons of clarity, only some of the slots 33 are provided with a reference symbol.

[0080] The slots 33 are expediently provided in at least one—in the present example, two—crossbeams 34, which are arranged between two side walls 36 of the substrate holder 30. With two or more crossbeams 34, two of the slots 33 in different crossbeams 34 are aligned with each other, so that exactly one substrate blank 2 can be arranged in these two slots 33.

[0081] The holding device 31 is expediently configured to hold the substrate blanks 2 such that, when the substrate holder 30 is aligned horizontally, a substrate blank surface 4 is inclined relative to the vertical. For this purpose, the slots 33 can be introduced into the cross members 34 at a corresponding angle. Preferably, the slots 33 are aligned such that an inclination of the substrate blank surface 4 relative to the vertical of more than 0°, preferably 10° or more, but not more than 90°, is achieved.

[0082] The substrate holder 30 further comprises a bridge 35, on which the substrate blanks 2, held in particular in the slots 33 of the holding device 31, can be placed with a lower end. The bridge 35 also connects the side walls 36. Preferably, the bridge 35, as shown in Figure 5, also comprises slots 33, so that the ends of the substrate blanks 2 can also be fixed when arranged in the slots 33 of the cross members 34.

[0083] If necessary, several bridges 35 and cross beams 34 can be arranged one behind the other, i.e. in a direction perpendicular to the plane of the figure, in order to increase the capacity of the substrate holder 30.

[0084] The collecting device 32 preferably has a plurality of collecting elements 37, of which only some are provided with reference symbols for reasons of clarity. In the present example, the collecting elements 37 are designed as pins which protrude horizontally from at least one, in this case both, cross members 34. The collecting elements 37 are expediently arranged adjacent to the slots 33. In this case, one collecting element 37 can be provided per slot 33 and cross member 34. In other words, each slot 33 in a cross member 34 can be assigned a collecting element 37. In principle, however, several collecting elements 37 per slot 33 are also conceivable.

[0085] After being removed from the substrate blank 2, the target substrate 5 can fall with a lower end onto the bridge 35 while being held laterally by the collecting elements 37.

[0086] Conveniently, the bridge 35 has a plurality of recesses 38, each of which is designed to fix a detached target substrate 5. Fixing here is, in particular, a stabilization of the horizontal position of the detached target substrate 5. In other words, the fixing can prevent or at least impede movement along the bridge 35, in particular of an end of the target substrate 5 facing the bridge 35.

[0087] The recesses 38 can be designed, in particular arranged, in such a way that a target substrate 5 removed from the substrate blank 2 slides, in particular automatically, into one of the recesses 38. For this purpose, a recess 38 can be provided adjacent to a slot 33 in the bridge 35. List of reference symbols

[0088] 1 system

[0089] 2 substrate blank

[0090] 3 Laser radiation

[0091] 4 Substrate blank surface

[0092] 5 Target substrate

[0093] 6 Outer contour

[0094] 7 Line

[0095] 7a outer line

[0096] 7a ' outer line

[0097] 7b middle line

[0098] 7b ' middle line

[0099] 7c inner line

[0100] 8 Area

[0101] 9 through hole

[0102] 20 laser device

[0103] 30 substrate holders

[0104] 31 Holding device

[0105] 32 Catch device

[0106] 33 slot

[0107] 34 cross members

[0108] 35 Bridge

[0109] 36 side wall

[0110] 37 Catch element

[0111] 38 Deepening

[0112] 40 Etching device

[0113] 41 Etching medium

[0114] 50 aftertreatment device

[0115] 100 procedures

[0116] S 1-S5 procedural steps

Claims

Patent claims 1. Method (100) for substrate etching, in which a substrate blank (2) is arranged (S2) in a substrate holder (30) and a substrate blank surface (4) is treated (S3) with an etching medium (41), characterized in that the substrate blank (2) is irradiated (S1) with laser radiation (3) along an outer contour (6) of a target substrate (5) before the treatment with the etching medium (41), so that the target substrate (5) is released from the substrate blank (2) during the treatment with the etching medium (41).

2. Method (100) according to claim 1, characterized in that the substrate blank (2) is irradiated with the laser radiation (3) along the outer contour (6) of the target substrate (5) in such a way that, during the treatment of the substrate blank (2) with the etching medium (41), through holes (9) are produced in the substrate blank (2) along the outer contour (6) of the target substrate (5).

3. Method (100) according to one of the preceding claims, characterized in that the substrate blank (2) is irradiated with the laser radiation (3) along the outer contour (6) of the target substrate (5) in such a way that during the treatment of the substrate blank (2) with the etching medium (41) through holes (9) are produced in the substrate blank (2) along the outer contour (6) of the target substrate (5) at a predetermined distance from one another and, after a predetermined treatment time of the substrate blank (2) with the etching medium (41), adjacent through holes (9) connect to one another.

4. Method (100) according to one of the preceding claims, characterized in that the target substrate (5) is removed from the substrate blank (2) essentially free of etching marks.

5. Method (100) according to one of the preceding claims, characterized in that the substrate holder (30) is introduced into an etching medium bath for treating the substrate blank surface (4) with the etching medium (41) and the substrate holder (30) is removed from the etching medium bath immediately after the target substrate (5) has been released from the substrate blank (2).

6. Method (100) according to one of the preceding claims, characterized in that the detached target substrate (5) is collected (S4) by means of the substrate holder (2).

7. Method (100) according to one of the preceding claims, characterized in that the substrate blank (2) is held by the arrangement in the substrate holder (30) such that the substrate blank surface (4) is inclined relative to the vertical when the substrate holder (30) is aligned horizontally.

8. Method (100) according to claim 7, characterized in that the substrate blank surface (4) is inclined by an angle between 0° and 90° inclusive, preferably 10° or more, relative to the vertical.

9. Method (100) according to one of the preceding claims, characterized in that the substrate blank (2) is irradiated with laser radiation (3) on one side substantially perpendicular to the substrate blank surface (4).

10. Method (100) according to one of the preceding claims, characterized in that the substrate blank (2) is irradiated with laser radiation (3) on two opposite sides substantially perpendicular to the substrate blank surface (4).

11. Method (100) according to one of the preceding claims, characterized in that the irradiation is carried out on the two opposite sides with different laser parameters.

12. Method (100) according to one of the preceding claims, characterized in that when the substrate blank (2) is irradiated with laser radiation (3) along the outer contour (6) of the target substrate (5), laser pulses impinge on the substrate blank surface (4) at least in sections in the region (8) of regularly spaced impact points, the impact points lying on a line (7; 7a, 7b, 7c).

13. Method according to one of the preceding claims, characterized in that during the irradiation of the substrate blank (2) with laser radiation (3) along the outer contour (6) of the target substrate (5) laser pulses are generated in the region of impact points on hit the substrate blank surface (4), wherein the impact points lie at least partially on two or more lines (7a, 7b, 7c) running parallel to one another.

14. Method according to one of the preceding claims, characterized in that when the substrate blank (2) is irradiated with laser radiation (3) along the outer contour (6) of the target substrate (5), laser pulses impinge on the substrate blank surface (4) in the region of impact points, wherein the impact points lie at least in sections on two or more nested lines (7a, 7b, 7c) and an inner line (7c) delimits the target substrate (5).

15. Method (100) according to one of the preceding claims, characterized in that the substrate surface (4) is treated with an etching medium (41) containing potassium hydroxide, tetramethylammonium hydroxide, sodium hydroxide and / or lithium hydroxide.

16. Method according to one of the preceding claims, characterized in that the substrate blank surface (4) is treated with the etching medium (41) at a temperature of 90 °C or more.

17. Substrate holder (30) for holding substrate blanks (2), in particular for use in the method (100) according to one of claims 1 to 16, with a collecting device (32) which is designed to collect a target substrate (5) which is dissolved out of the substrate blank (2) during treatment of a held substrate blank (2) with an etching medium (41). Substrate holder (30) according to claim 17, comprising a holding device (31) for holding substrate blanks (2), which has a plurality of slots (33) for inserting the substrate blanks (2) such that contact of the substrate holder (30) with the substrate blanks (2) remains limited to a section lying outside a region corresponding to the target substrate (5) to be removed. Substrate holder (30) according to one of claims 17 or 18, wherein the collecting device (32) has a plurality of collecting elements (37) designed as pins. Substrate holder (30) according to claims 18 and 19, wherein the collecting elements (37) are arranged adjacent to the slots (33) and at least one collecting element (37) is assigned to each slot (33) in order to collect the target substrate (5) removed from the substrate blank (2) held by the respective slot (33).Substrate holder (30) according to one of claims 17 to 20, comprising two side walls (36) and a bridge (35) between the two side walls (36), wherein lower ends of the substrate blanks (2) can be placed on the bridge (35) and / or onto which detached target substrates (5) can fall with a lower end. Substrate holder (30) according to claim 21, wherein the bridge (35) has a plurality of recesses (38), each of which is designed to stabilize a detached target substrate (5). Substrate holder (30) according to claim 22, wherein the recesses (38) are designed such that a target substrate (5) removed from the substrate blank (2) automatically slides into one of the recesses (38) with its lower end. System (1) for substrate etching, in particular for carrying out a method (100) according to one of claims 1 to 16, with - a laser device (20) which is designed to irradiate a substrate blank (2) with laser radiation (3) along an outer contour (6) of a target substrate (5) in such a way that the target substrate (5) is released from the substrate blank (2) during treatment with an etching medium (41), - a substrate holder (30), in particular according to one of claims 17 to 23, in which the substrate blank (2) can be arranged, and - an etching device (40) which is designed to treat the irradiated substrate blank (2) arranged in the substrate holder (30) with the etching medium (41).

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