Device and method for drying disc-shaped substrates

Abstract

Proposed is a device for drying disc-shaped substrates (8), comprising a body (1) having a horizontal main direction of extent (2) and having a cross-sectional profile (3) transverse to the main direction of extent (2), the cross-sectional profile tapering upwardly in the vertical direction, wherein: the body (1) has on its top side a plurality of support positions (5) which are suitable for supporting disc-shaped substrates (8); the plurality of support positions (5) are arranged along the main direction of extent (2); the plurality of support positions (5) are adjoined by surfaces of the body which slope downwardly from the support positions (5); and at least a proportion of the downwardly sloping surfaces which adjoin the support positions (5) is hydrophilic and has a periodic microstructure, at least in a proportion (7) of their upper portion.

Description

[0001] Device and method for drying disc-shaped substrates

[0002] Technical area

[0003] The present invention relates to an apparatus for drying disc-shaped substrates and a method for drying disc-shaped substrates.

[0004] State of the art

[0005] Wafers of semiconductor material, such as wafers of monocrystalline silicon (silicon wafers), are manufactured in a variety of process steps, including pulling a single-crystal rod from a melt, sawing the crystal into wafers, grinding, edge rounding, polishing, and chemical cleaning of the wafers. Chemical cleaning removes impurities and passivates the wafer surfaces. One form of chemical cleaning is wet cleaning, which requires subsequent drying of the wafers.

[0006] During chemical cleaning, the disc-shaped substrates are immersed for a short time in one or more baths containing a liquid and then removed slowly so that as little liquid residue as possible remains on the substrates. The reason for this is that the liquid residue adhering to the disc-shaped substrates represents a source of contamination and can significantly affect the quality of the surface of the disc-shaped substrate, especially in the edge area. Liquid residues that initially adhere between the disc holder and a substrate can spread to the side surfaces of the substrate and, after drying, leave particles on the substrate. Since the liquid residues can contain semi-volatile compounds such as metal particles, the contaminants remain on the disc surface even after the liquid has evaporated.

[0007] For drying disc-shaped substrates immersed in liquid, a process is available in which the substrates are transferred from the liquid into a gas space containing vapor that does not condense on the substrates and reduces the surface tension of the liquid residues adhering to the substrates. The process and the physical effect utilized are described in EP0385536 A1, as is a device suitable for carrying out such a process.

[0008] Further devices and methods for improving the cleaning quality with regard to remaining particles on the disc-shaped substrate are also described in the documents DE 10 2014 207 266 A1, EP 3 840 021 A1, EP 3 840 022 A1 and EP 3 840 023 A1. However, when these devices and methods are used, particles still remain on the surface of the disc-shaped substrates after drying, which reduce the quality of the disc-shaped substrates. The object of the present invention is to further improve the drying devices and methods described in the prior art and thus reduce the number of particles that remain on the dried disc-shaped substrates.

[0009] Technical problem of the invention and its solution

[0010] The aim of the present invention is therefore to provide a device and a method for drying disc-shaped substrates which make it possible to remove the liquid residues, and thus the particles contained in the liquid which adhere to the disc-shaped substrates, better and more efficiently.

[0011] The object is achieved according to the invention by a device for drying disc-shaped substrates according to the first aspect of the present invention.

[0012] This device comprises a body with a horizontal main extension direction and a cross-sectional profile transverse to the main extension direction, which tapers upwards in the vertical direction, wherein the body has on its upper side a plurality of support positions which are suitable for supporting disc-shaped substrates which are arranged in a plurality of support positions along the main extension direction, adjoining the plurality of support positions are surfaces of the body which slope downwards from the support positions, and at least some of the sloping surfaces adjoining the support positions are hydrophilic at least in a part of their upper section and have a periodic microstructure.

[0013] It was surprisingly found that by designing the surfaces adjacent to the support positions and sloping from the support positions with an upper section that is hydrophilic and has a microstructure, liquid residues can be removed more quickly and efficiently and thus the amount of contamination on the surface of a disc-shaped substrate can be further reduced.

[0014] According to the second aspect, the present invention is directed to a method for drying disc-shaped substrates immersed in a liquid. The method comprises the following steps: positioning the disc-shaped substrates immersed in the liquid on the device according to the first aspect of the present invention; and transferring the disc-shaped substrates with the device from the liquid into a gas space containing a vapor that does not condense on the disc-shaped substrates and reduces the surface tension of liquid residues adhering to the disc-shaped substrates.

[0015] In this process, residual liquid between the disc-shaped substrates and the device supporting the discs can drain away via the downwardly inclined surfaces of the body adjacent to the support positions and thus be removed. Thus, there is no need to actively remove the residual liquid between the disc-shaped substrates and the disc holder.

[0016] Because the upper section is hydrophilic, aqueous liquid residues or liquid residues containing polar solvents that have accumulated at the lower edge of the disc-shaped substrates can more easily transfer to the adjacent, downward-sloping surfaces of the body at the contact points. It was also surprisingly found that liquid residues, especially water, are better absorbed and drained away from a hydrophilic surface with a periodic microstructure due to the capillary forces acting on it.

[0017] Due to the periodic microstructure and the hydrophilicity, at least in the upper section of the sloping surfaces adjacent to the support positions, liquid residues adhering to the lower edge of the discs supported on the body can more easily transfer to the surfaces adjacent to the support positions and be drained away from the support positions via the sloping, hydrophilic, microstructured surfaces. This enables efficient removal of liquid residues from the disc-shaped substrates. This can reduce the number of particles remaining on the disc-shaped substrates after drying. In addition, the improved drainage of the liquid residues when removing the substrates from the bath further reduces the net removal of cleaning liquid, as a larger proportion of the liquid flows back into the cleaning bath instead of evaporating. This increases the economic efficiency of chemical cleaning.In addition, the improved drainage of liquid residues can reduce the amount of liquid evaporating from the substrate surface, which leads to an improvement in the atmosphere in the cleanroom.

[0018] Short description of the characters

[0019] Fig. 1 shows a body (1) of an inventive device for drying disc-shaped substrates. The body has a cross-sectional profile (3) transverse to the main direction of extension (2), which tapers upwards in the vertical direction. On its upper side, the body has a zigzag-shaped edge profile (6) that runs along the main direction of extension (2). The individual edges (4) that abut one another in the main direction of extension form deeper creases (5) that serve as support positions for the disc-shaped substrates.

[0020] Fig. 2a shows the cross-sectional profile (3), and Fig. 2b and Fig. 2c show the longitudinal profile along the main extension direction (2) of a body (1) of a device according to the invention. Fig. 2b and Fig. 2c each show that at least some of the sloping surfaces adjacent to the support positions (5) for the disc-shaped substrates (8) have a periodic microstructure, at least in a part (7) of their upper section.

[0021] Fig. 3 ad show atomic force micrographs of the periodic microstructures that were applied to the surfaces of the body of a device according to the invention adjacent to the support positions in embodiments 1 to 4. These four microstructures have a period of 21 pm and a profile depth in the range of 1 pm to 20 pm.

[0022] Detailed description of the invention

[0023] Disc-shaped substrates within the meaning of the present invention are, for example, discs made of semiconductor material, preferably discs made of monocrystalline silicon, which is optionally doped. The disc-shaped substrates preferably have a diameter of 150 to 450 mm, particularly preferably 200 mm or 300 mm, most preferably 300 mm. The thickness of the disc-shaped substrates is preferably in the range of 500 pm to 1500 pm, preferably 600 pm to 1000 pm.

[0024] The device for drying disc-shaped substrates according to the first aspect of the present invention comprises a body with a horizontal main extension direction and a cross-sectional profile transverse to the main extension direction, which tapers upwards in the vertical direction. Preferably, the cross-sectional profile is symmetrical with respect to a vertical axis of symmetry. Preferably, the cross-sectional profile of the body has an acute angle in its upper part. In this case, the apex of the acute angle, as the highest point of the cross-sectional profile, forms the support point for supporting the disc-shaped substrate.

[0025] The body preferably tapers upwards in a vertical direction to an edge or an edge profile. The edge profile consists of several abutting edges, which preferably lie in the same plane, preferably in a plane perpendicular to the cross-sectional profile. At each edge of the edge profile, two surfaces sloping away from the edge abut one another. The points at which two edges (4) of the edge profile (6) abut one another are referred to below as kinks (5). For example, the edge profile (6) of the body (1) can be a zigzag profile, as shown in Fig. 1, Fig. 2b and Fig. 2c. The edge profile (6) preferably runs along the main extension direction (2). This means that the edge profile (6) and the main extension direction (2) lie in the same plane, which is preferably arranged perpendicular to the cross-sectional profile (3).

[0026] The body (1) has on its upper side a plurality of support positions (5) which are suitable for supporting disc-shaped substrates (8), wherein the plurality of support positions are arranged along the main extension direction (2) and border on surfaces of the body (1) which slope downwards starting from the support positions (5) (see Figs. 2b and 2c). The support positions (5) are preferably formed by one or more edges on the upper side of the body, wherein two sloping surfaces abut one another at each edge. Preferably, the support positions (5) are formed by edges at which surfaces of the body which slope downwards from the edge abut one another. At least some of the sloping surfaces bordering the support positions (5) are hydrophilic at least in a part (7) of their upper section and have a periodic microstructure in this part.Preferably, all sloping surfaces adjacent to the support positions (5) have at least a part (7) of their upper section that is hydrophilic and has a periodic microstructure. In a preferred embodiment, the part (7) of the upper section that is hydrophilic and has a periodic microstructure is more hydrophilic than the surface of a wafer made of monocrystalline silicon. In an embodiment shown in Fig. 2b and Fig. 2c, the part (7) of the upper section of the sloping surfaces adjacent to the support positions that is hydrophilic and has a periodic microstructure has a rectangular shape.

[0027] The part of the upper section that is hydrophilic and has a periodic microstructure is understood to mean the surface that is both hydrophilic and has a periodic microstructure. Thus, if, in one embodiment, the sloping surfaces adjacent to the support positions are completely hydrophilized, for example by subjecting the entire body to gas-phase fluorination, the part of the upper section that is hydrophilic and has a periodic microstructure is understood to mean only that part of the completely hydrophilized side surface that has a periodic microstructure. The part of the upper section that is hydrophilic and has a periodic microstructure is therefore the intersection of the surfaces that are, on the one hand, hydrophilic and, on the other hand, provided with a periodic microstructure.A hydrophilic surface in the sense of the present invention is preferably characterized in that a water droplet on it has a contact angle a of not more than 50°.

[0028] The sloping surfaces adjacent to the support positions may also be designed to have an upper section and a lower section, and the upper section is more hydrophilic than the lower section.

[0029] If the body tapers upwards in the vertical direction to an edge, for example if the body is designed as a wedge-shaped body, the upward-facing edge serves to support the disc-shaped substrates. In this case, the one upward-facing edge provides several support positions. If the body tapers upwards in the vertical direction to an edge profile, the support positions are preferably formed by kinks in the edge profile, particularly preferably by the downward-facing kinks. If the edge profile is a zigzag profile, the kinks preferably serve as a support position for the disc-shaped substrates, from which two edges run upwards. A support position can therefore also be formed by two edges that run on the upper side of the body along the main direction of extension, are adjacent to one another, and have a different inclination with respect to the horizontal.In this case, four sloping surfaces border the support position.

[0030] The support position can also be configured as a recess on the upper side of the body, transverse to the main extension direction. The recess can reduce or completely prevent slipping or tilting of the disc-shaped substrate supported at the support position along the main extension direction, especially when the disc-shaped substrates are arranged transversely to the main extension direction. The extent of the individual recesses along the main extension direction exceeds the thickness of the disc-shaped substrates, so that the latter can be inserted into the recesses and supported by them transversely to the main extension direction. The recesses preferably run in the transverse direction, i.e., perpendicular to the main extension direction and perpendicular to the vertical. The recesses can be cuboid-shaped, beveled, V-shaped, or rounded on their underside.Adjacent to the support positions are surfaces of the body that slope downwards from the support positions. At least some of these surfaces have, at least in a part of their upper section, a surface that is hydrophilic and has a periodic microstructure. Preferably, all sloping surfaces adjacent to the support positions have, at least in a part of their upper section, a region that is hydrophilic and has a periodic microstructure. In a particularly preferred embodiment, the entire upper section of all sloping surfaces adjacent to the support positions is hydrophilic and provided with a microstructure.

[0031] The body can be made of metal, ceramic, or plastic. The body is preferably made of a thermoplastic, most preferably a high-temperature-resistant thermoplastic. The thermoplastic can be, for example, a polyaryletherketone, preferably polyetheretherketone (PEEK). PEEK exhibits high chemical resistance, wear resistance, and good sliding properties. The body of the device according to the invention for drying disc-shaped substrates is therefore preferably made of PEEK.

[0032] The upper section preferably borders the support position. Each support position, which is preferably formed by one or more edges, is preferably bordered by at least two downwardly sloping surfaces, each with an upper section that is hydrophilic and has a periodic microstructure. The at least two downwardly sloping surfaces are preferably arranged on opposite sides, starting from the respective support position.

[0033] A downwardly sloping surface within the meaning of the present invention can, for example, have an inclination of more than 10° and less than 80° with respect to the vertical. A sloping surface within the meaning of the present invention can also be curved or arched. Sloping within the meaning of the present invention means that the part of the surface adjacent to the support position is located higher than a part of the surface further away from the support position. Thus, residual liquid can be drained away from the substrates supported on the support positions via the sloping surfaces with the aid of gravity. The upper section preferably borders directly on a support position of the body.Because the upper section is designed to be hydrophilic, aqueous liquid residues, for example in the form of drops, can be more easily transferred from the lower edge region of the disc-shaped substrates supported by the body to the body and thus removed from the substrate. Preferably, the hydrophilic, upper section of the sloping surfaces adjacent to the support positions is characterized in that a water droplet on it has a contact angle α of no more than 50°, more preferably no more than 45°, most preferably no more than 40°. In one embodiment of the present invention, the hydrophilic, upper section of the sloping surfaces adjacent to the support positions is designed such that a water droplet on it has a contact angle of no less than 20° and no more than 30°.

[0034] Preferably, the surface in the upper section of the downwardly sloping surfaces of the body adjacent to the support positions is more hydrophilic than the surface of the disc-shaped substrate, in particular more hydrophilic than the surface of a disc-shaped substrate made of monocrystalline silicon. In this case, aqueous liquid residues can flow from the substrate to the upper section. Furthermore, in this case, a water bridge that forms upon separation of substrate and body is drawn to the more hydrophilic body, or to the more hydrophilic upper section of the sloping surface adjacent to the support position, and thus removed from the substrate. Due to gravity and capillary forces, these liquid residues then flow away over the sloping surfaces of the body.

[0035] Hydrophilicity is a measure of wettability. A more hydrophilic surface therefore has better wettability with respect to water. In the present invention, the contact angle α of a water droplet, particularly preferably a droplet of deionized water, is used as a measure of the surface's hydrophilicity.

[0036] The contact angle a can be determined according to the following procedure:

[0037] (i) wetting at least one point of a surface, preferably at least one point of the upper portion of a sloping surface of the body, with one drop of a liquid;

[0038] (ii) taking an image of each drop, preferably a shadow image; (iii) determining the contour of the respective drop based on the respective image, preferably the shadow image, using suitable software; and

[0039] (iv) Determining the contact angle between the surface and the respective droplet based on the determined contour of the respective droplet.

[0040] In step (i), the area of ​​the surface to be examined is wetted with a drop of water, preferably a drop of deionized water. In step (ii), an image of the drop, preferably a shadow image, is taken using a camera. In step (iii), the contour of the drop is then determined based on the image using suitable software. Contour detection can be carried out using a grayscale analysis of the image, and a geometric model describing the drop contour can then be identified. The identification of the geometric model describing the drop contour can be achieved, for example, by fitting. The contact angle results from the angle between the determined drop contour function and the surface of the area under investigation, the projection of which in the drop image can be referred to as the baseline.Geometric models that describe the drop contour can be circles, conic sections, ellipses or polynomials.

[0041] The hydrophilicity of a surface can be modified by physical methods, such as plasma treatment, or by chemical methods, such as surface reactions, coating or incorporation of a chemical compound.

[0042] The hydrophilicity of a surface of a thermoplastic such as PEEK can be increased by direct gas-phase fluorination. For example, the surface of a PEEK body can be treated with a gas mixture of fluorine and air, where the gas mixture can have a fluorine content of 5 mol%.

[0043] Surfaces can also be hydrophilized using a laser. For example, surfaces of metallic materials or ceramics can be cleaned with a laser in an air atmosphere, resulting in a more hydrophilic surface. Hydrophilization of a surface can also be achieved using a laser and a silicating fluid, which cleans the surface and additionally functionalizes it. This makes the treated surface even more hydrophilic. Laser silicating can be performed in an immersion bath.

[0044] A periodic microstructure, within the meaning of the present invention, is a structure on the surface of a body with elevations and / or depressions, wherein the elevations and depressions are regularly arranged. Preferably, the microstructuring step takes place before the surface hydrophilization step. This ensures that the depressions of the microstructure created by removing material also exhibit the desired hydrophilic surface properties.

[0045] The periodic microstructure is preferably created using direct laser interference patterning (DLIP). DLIP is a laser-based technology that uses the physical principle of interference between high-intensity, coherent laser light beams to create functional periodic microstructures. This process is described, for example, by T. Kunze et al. in the article "Direct laser interference patterning: from fundamentals to industrial applications," Lasers in Manufacturing Conference 2017. Interference patterns are created by splitting a coherent laser beam, for example using beam splitters, into two or more partial beams, which are then superimposed on the workpiece using multiple mirrors. The interference of multiple laser beams leads to effective modulation of the laser intensity profile.The patterns can be transferred directly onto any material that absorbs the laser energy at the selected wavelength. The patterning process is based on photothermal, photophysical, or photochemical mechanisms, depending on the type of material.

[0046] The surface of the body of the device according to the invention is preferably made of a thermoplastic or is coated with a thermoplastic. The thermoplastic is particularly preferably a polyaryletherketone, most preferably a polyetheretherketone (PEEK). For processing these plastics, an infrared ultrashort pulse laser with a pulse duration of no more than 500 ps, ​​preferably no less than 5 ps and no more than 100 ps, ​​and an interference module of the CORErapid IR30.4 type from Fusion Bionic are preferably used.

[0047] The periodic microstructure preferably has a profile height or profile depth of not less than 0.1 pm and not more than 50 pm, more preferably not less than 0.5 pm and not more than 20 pm, most preferably not less than 1 pm and not more than 10 pm. The terms profile height and profile depth are used synonymously. The profile height or profile depth is the height difference between the regularly arranged elevations and depressions, in a direction perpendicular to the surface exhibiting the microstructure.

[0048] When the profile depth of the periodic microstructure lies within this range, a positive effect on the removal of liquid residues was observed. It was observed that liquid residues at the contact points between the disc-shaped substrates and the support positions of the body of the device according to the invention can be better transferred to the sloping surfaces of the body adjacent to the support positions and can be removed from the body via these surfaces if these surfaces are provided with a microstructure with a profile depth within the above-mentioned range. The transfer of liquid residues from a disc-shaped substrate to the body of the drying device and the removal of the transferred liquid residues from the body is particularly good when the periodic microstructure has a profile depth of no less than 1 μm and no more than 10 μm.

[0049] The periodic microstructure preferably consists of parallel arranged depressions and elevations, circular depressions, or circular elevations. In one embodiment, the periodic microstructure consists of columnar elevations arranged in rows (see Fig. 3b). The terms circular elevations and columnar elevations are used synonymously. A periodic microstructure consisting of parallel arranged depressions is particularly preferred. The depressions are preferably configured as channels with a width of not less than 1 pm and not more than 50 pm, more preferably as channels with a width of not less than 1 pm and not more than 30 pm, most preferably as channels with a width of not less than 5 pm and not more than 20 pm.By means of capillary forces, liquid residues, for example water droplets, can be taken up by the channels and drained away along these from the body of the device according to the invention. The transport of liquid residues along the channels by means of capillary forces is particularly efficient if the channels have a width of not less than 1 pm and not more than 50 pm. The transport of liquid residues along the channels can be further improved if the channels have a width of not less than 5 pm and not more than 20 pm. The parallel depressions and elevations of a periodic microstructure comprising parallel channels are preferably inclined from the horizontal so that liquid residues, in particular water droplets, can be drained away along the depressions with the aid of gravity in addition to the capillary forces. The channels are preferably arranged perpendicular to the main direction of extension.In a preferred embodiment, the periodic microstructure consists of parallel channels.

[0050] The periodic microstructure preferably has a period of not less than 1 pm and not more than 500 pm, more preferably not less than 5 pm and not more than 100 pm, most preferably not less than 10 pm and not more than 50 pm. The period preferably corresponds to the magnitude of the smallest translation vector in a direction along which both depressions and elevations are arranged. In a preferred embodiment, the period corresponds to the distance between the regularly arranged elevations or the distance between the regularly arranged depressions. It has been found that the capillary forces and thus the transfer and removal of liquid residues from the substrate across the body and away from it can be further improved if the period of the periodic microstructure lies in the range specified above.With a period of no less than 10 pm and no more than 50 pm, the transfer of liquid residues from the substrates to the support positions of the body, and the flow of these liquid residues away from the support positions, can be further improved. The profile depth, period, and extent of elevations and depressions of the periodic microstructure can be determined using atomic force microscopy, among other methods.

[0051] According to the second aspect, the present invention is directed to a method for drying disc-shaped substrates immersed in a liquid. The method comprises the following steps: positioning the disc-shaped substrates immersed in the liquid on the device according to the first aspect of the present invention; and transferring the disc-shaped substrates with the device from the liquid into a gas space containing a vapor that does not condense on the disc-shaped substrates and reduces the surface tension of liquid residues adhering to the disc-shaped substrates.

[0052] In this process, liquid residues can drain from the disc-shaped substrates over the downwardly inclined surfaces of the device body adjacent to the support positions and thus be removed. Thus, there is no need to actively remove the liquid residues between the disc-shaped substrates and the disc holder.

[0053] A vapor that does not condense on the substrates has a vapor pressure that is not saturated at the temperature of the bath and the substrates, whereas a vapor that condenses on the substrates has such a saturated vapor pressure. The substrates can be treated in various liquid baths. If the cleaning bath contains water, the vapor of an organic solvent, preferably one or more compounds selected from alcohols, glycols, aldehydes, esters, ketones, or tetrahydrofuran, is preferably used. The method according to the invention can also be applied if the bath contains other polar liquids, for example alcohols. The substrates can then be brought into contact, for example, directly from the alcohol with the vapor of the organic solvent 1,1,1-trifluorotrichloroethane.

[0054] Because at least some of the sloping surfaces adjacent to the support positions are hydrophilic at least in part of their upper section and have a periodic microstructure, aqueous liquid residues or liquid residues with polar solvent components that have accumulated at the lower edge of the disc-shaped substrates can more easily transfer to the body at the support positions and can then be removed from the surfaces and returned to the liquid bath.

[0055] Description of embodiments and comparative examples In the embodiments 1 to 4, a device according to the invention as shown in Fig. 1 was used to dry 50 discs of single-crystal silicon with a diameter of 300 mm and a thickness of 750 pm.

[0056] The body (1) of the device tapers upwards to an edge profile (6) with a zigzag shape along the main extension direction (2) (see Fig. 2b and Fig.

[0057] 2c). The body (1) was made of PEEK. Direct laser interference structuring (DLIP) was used to create a periodic microstructure on a portion (7) of the upper section of the sloping side surfaces adjacent to the support positions (5) of the body (1). This was done using an infrared ultrashort pulse laser with a wavelength of 1064 nm and a pulse duration of 12 ps, and a CORErapid IR30.4 interference module from Fusion Bionic.

[0058] In Example 1, a periodic microstructure consisting of circular depressions with a profile depth of 10 pm and a period of 21 pm was created. Fig. 3a shows atomic force microscopy images of this periodic microstructure.

[0059] In Example 2, a periodic microstructure consisting of circular elevations with a profile depth of 1 pm and a period of 21 pm was created. Fig. 3b shows atomic force microscopy images of this periodic microstructure.

[0060] In Example 3, a periodic microstructure consisting of channels with a profile depth of 10 pm and a period of 21 pm was created. Fig. 3c shows atomic force microscopy images of this periodic microstructure.

[0061] In Example 4, a periodic microstructure consisting of channels with a profile depth of 5 pm and a period of 21 pm was created. Fig. 3d shows atomic force microscopy images of this periodic microstructure.

[0062] Subsequently, the side surfaces provided with the periodic microstructure were hydrophilized by treating them with a gas mixture of 5 mol% fluorine and air as a purge gas.

[0063] Thus, the bodies produced in Examples 1 to 4 differed only in the geometry / pattern of the periodic microstructure and its profile depth. In Comparative Example 1, the same device was used as in the Example, with the exception that the sloping surfaces of the body of the device were not provided with a microstructure. Otherwise, the procedure was exactly the same as in the Example.

[0064] In Comparative Example 2, the same microstructure was produced as in Example 1, but subsequent hydrophilization by treatment with a gas mixture of fluorine and air was omitted.

[0065] The bodies produced in Examples 1 to 4 and Comparative Examples 1 and 2 were subsequently used for drying. For this purpose, 50 slices each were transferred from a water-filled basin into a gas chamber containing isopropanol vapor, standing on their upper edges transverse to the main extension direction of the device.

[0066] The dried semiconductor wafers were examined for the presence of particles in the region of the support positions on the body. A comparison of exemplary embodiments 1 to 4 with comparative examples 1 and 2 showed that the drying carried out using the device according to the invention and the method according to the invention in exemplary embodiments 1 to 4 resulted in significantly fewer residues on the dried wafers. The fewest residues were observed in exemplary embodiments 3 and 4, with exemplary embodiment 4 delivering the best results. This showed, on the one hand, that a microstructure with channels can drain away liquid residues particularly well, and, on the other hand, that profile depths in the range of 1 μm to 10 μm, and in particular profile depths of 5 μm, can absorb liquid residues particularly well and drain them away from the support surface.

Claims

Patent claims 1. A device for drying disc-shaped substrates (8), comprising a body (1) with a horizontal main direction of extension (2) and a cross-sectional profile (3) transverse to the main direction of extension (2), which cross-sectional profile tapers upwards in the vertical direction, wherein the body (1) has a plurality of support positions (5) on its upper side, which support positions are suitable for supporting disc-shaped substrates (8) arranged in a plurality of support positions (5) along the main direction of extension (2), adjoining the plurality of support positions (5) are surfaces of the body which slope downwards starting from the support positions (5), and at least some of the sloping surfaces adjoining the support positions (5) are hydrophilic at least in a part (7) of their upper section and have a periodic microstructure.

2. Apparatus for drying disc-shaped substrates according to claim 1, wherein the hydrophilic upper portion is characterized in that a water droplet thereon has a contact angle α of not more than 50°.

3. Device for drying disc-shaped substrates according to one of claims 1 or 2, characterized in that the periodic microstructure has a profile depth of not less than 0.1 pm and not more than 50 pm.

4. Apparatus for drying disc-shaped substrates according to one of claims 1 to 3, characterized in that the periodic microstructure has a period of not less than 1 pm and not more than 500 pm.

5. Device for drying disc-shaped substrates according to one of claims 1 to 4, characterized in that the periodic microstructure comprises parallel channels with a width of not less than 1 pm and not more than 50 pm.

6. Device for drying disc-shaped substrates according to one of claims 1 to 5, characterized in that the body consists of a thermoplastic material or is coated with a thermoplastic material.

7. Device for drying disc-shaped substrates according to one of claims 1 to 6, characterized in that the thermoplastic material is a polyaryletherketone, preferably polyetheretherketone.

8. Device for drying disc-shaped substrates according to one of claims 1 to 7, characterized in that the support positions are designed such that the disc-shaped substrates supported thereon are arranged transversely to the main extension direction.

9. Device for drying disc-shaped substrates according to one of claims 1 to 8, characterized in that the body tapers vertically upwards to an edge or an edge profile.

10. Apparatus for drying disc-shaped substrates according to one of claims 1 to 9, wherein each support position is characterized by a kink in the edge profile.

11. Device for drying disc-shaped substrates according to one of claims 1 to 10, characterized in that the body is designed such that the disc-shaped substrates rest on the highest point of the respective cross-sectional profile at the support positions.

12. A method for drying disc-shaped substrates immersed in a liquid, comprising positioning the disc-shaped substrates immersed in the liquid on the device according to one of claims 1 to 11; and transferring the disc-shaped substrates with the device from the liquid into a gas space containing a vapor that does not condense on the disc-shaped substrates and reduces the surface tension of liquid residues adhering to the disc-shaped substrates.

13. A method for drying disc-shaped substrates according to claim 12, comprising removing liquid residues between the disc-shaped substrates and the body of the device via the sloping surfaces of the body of the device adjacent to the support positions.

14. A method for drying disc-shaped substrates according to claim 13, characterized in that there is no need to actively remove the liquid residues between the disc-shaped substrates and the body of the device.

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