Wafer carrier arrangement and method for processing the back side of a wafer

Abstract

Wafer carrier arrangement, including: - a wafer, - a carrier system comprising a carrier and an elastomer layer, wherein the elastomer layer is oriented towards the wafer and - a bonding layer, wherein the compound layer is a sol-gel layer, fabricable from the monomers (1) Si(OR1)4, and one, two or all of the following monomers (2) Si(OR1)3R2, (3) Si(OR1)2R3R4 and (4) Si(OR1)R5R6R7, wherein each R1 independently represents H or a C1-C8 alkyl group, R2, R3, R4, R5, R6 and R7 each independently represent a C1-C 20 -Alkyl group, a fluorinated C1 - C 20 -Alkyl group, a C1 - C 20 -Aminoalkyl group, a C2-C 20-alkenyl group, an aryl group, a fluorinated aryl group, a singly, doubly or triply C1 - C4 alkylated aryl group, wherein the alkylations are independent of each other with respect to their number of carbon atoms and wherein the group may also be fluorinated, or a C3 - C 20 -Represent epoxy residue, where the stoichiometric ratio of the monomers (1) to the sum of the stoichiometric ratios of the monomers (2), (3) and (4) is 0.032 (1 : 31.25) to 1.6 (1.6 : 1) and The area with the lowest adhesive force in the arrangement is the interface between the bonding layer and the elastomer layer.

Description

[0001] The present invention relates to a wafer-support arrangement comprising a wafer, a support system comprising a support and an elastomer layer, and a compound layer, wherein the compound layer is a sol-gel layer. The invention further relates to a method for processing the back side of a wafer.

[0002] There is currently a high demand for the thinnest possible electronic components and circuits. In the production of such electronic components and circuits (diodes, transistors, ICs, sensors, etc.), structures and layers are deposited onto wafers (possibly doped disks of silicon, gallium arsenide, etc.) using various technologies to create the desired electronic functions. Currently, after completion of the necessary manufacturing steps, these wafers are coated on the front side (the active side, i.e., the side on which the deposited structures are located) with a protective film or other protective layer. This film or layer serves to protect the front side of the wafer, and especially the electrical and mechanical structures deposited on it, during the subsequent thinning and / or other processing of the back side of the wafer.Thinning is achieved through techniques such as grinding, lapping, sanding, etching or similar processes on the back of the wafer.

[0003] The aim of this approach is to reduce the original thickness of the wafer. The extent of this reduction is crucially determined by the expected mechanical and thermal stresses during thinning and / or subsequent process steps. Since the wafer has already undergone numerous process steps by the time it is thinned, it already represents a significant economic value. Therefore, the risk of wafer breakage must be minimized. Consequently, thinning to the desired degree is often not feasible, as this would result in excessive losses due to wafer breakage.

[0004] According to current technology, after thinning, the back of the wafer is often chemically treated to improve its fracture properties. Following any necessary cleaning steps, the protective film is peeled off the top of the wafer or removed by other means. Further manufacturing steps and / or measures to improve the wafer's properties, as well as tests such as quality control, may then follow. Frequently, the back of the thinned wafer is coated with a metallic layer. This coating process is usually carried out using sputtering or similar deposition methods in a vacuum and often involves thermal stress.

[0005] The wafer is then placed face down (active side up) onto a sawing foil, an expansion foil, or a frame. Next, the wafer is singulated, meaning it is cut into individual components (microplatelets, dies). This singulation is often performed using rotary cutting discs or other mechanical sawing devices. Laser cutting methods are also used. Alternatively, the wafers are sometimes broken during singulation, with additional techniques such as scoring being employed.

[0006] For the reasons mentioned above, it is very difficult to process or manufacture very thin wafers using conventional methods. These difficulties arise, among other things, from the fact that the wafer must be subjected to mechanical stresses during and after thinning. These stresses occur, for example, due to: - during the thinning of the wafer, whereby the wafer tends to ripple if it is thinned very much, - during the removal of the protective film or layer that protects the wafer front during thinning, - during the placement of the wafer onto the saw film and - during transport between the individual manufacturing steps, but especially during the coating of the back side, whereby at least thermal stresses also occur when the back side coating takes place after the wafer has been separated.

[0007] As an alternative to the methods mentioned above, methods are also used today in which the wafer is structured on the front side before the thinning process by grinding of scribed structures, scribing, chemical etching, plasma etching of trenches and / or structures in such a way that these structures are reached from the back side during the subsequent thinning process by mechanical and / or chemical methods so that the wafer is separated.

[0008] An alternative to the aforementioned techniques for thinning and further processing the wafer is disclosed in German patent application DE 103 53 530 and WO 2004 / 051708: These documents propose using a release layer and a support layer for thinning and subsequent processing of the wafer, wherein the release layer is a plasma-polymerized layer that adheres more strongly to the support layer than to the wafer. Due to the adhesion and delamination properties of the plasma-polymerized layer, which can be adjusted by a person skilled in the art using the plasma polymerization process, it is possible to design the layer such that it exhibits greater adhesion to the support layer than to the wafer. The adhesion strength to the wafer can be adjusted so that even a very thin wafer can be removed from the release layer (and the support layer) without excessive mechanical stress.

[0009] A disadvantage of the methods disclosed in the aforementioned documents is that the proposed support layer is not optimally suited: Particularly with three-dimensionally structured wafer surfaces (such as wafers with bumps or wafers with undercuts on their surface), the proposed support layer (e.g., polyimide or polyamide) is too hard. Since the plasma-polymer separating layer essentially covers the surface structures of the wafer with a layer of uniform thickness, gaps such as undercuts or spaces between bumps should be filled by the support layer material. However, if this is the case, the hardness of the support layer means that it cannot be removed from the wafer without damage.If the substrate layer does not completely fill the surface structures, voids remain that negatively affect the adhesion between the substrate and the release layer and can lead to unwanted inclusions. Furthermore, the different coefficients of thermal expansion of the substrate layer and the wafer create additional mechanical stress on the wafer.

[0010] WO 2007 / 09946 A1 discloses a separation process in which thinned wafers can be mechanically separated after thinning. This is made possible by the use of a plasma-polymer separation layer in combination with an elastomer layer.

[0011] Document WO 2012 / 081646 A1 deals with a method for manufacturing an optical element.

[0012] Document US 2010 / 0043608 A1 discusses a method for processing, in particular thinning, the back side of a wafer, as well as a wafer support arrangement for this purpose and a method for manufacturing such a wafer support arrangement.

[0013] AJ Atanacio et al. report in the journal “Surface & Coatings Technology”, Vol. 192 (2005), pages 354-364, on mechanical properties and adhesion characteristics of hybrid sol-gel thin films.

[0014] In light of the prior art, the object of the present invention was to provide an improved wafer-support arrangement that enables the mechanical separation of a processed wafer, particularly after thinning, without damaging the wafer. It was desirable to minimize the technical effort required to create the wafer-support arrangement, especially with regard to the equipment used.

[0015] This problem is solved according to the invention by a wafer-support arrangement as defined in the attached claims, comprising, inter alia, a wafer, a support system comprising a support and an elastomer layer, wherein the elastomer layer is oriented towards the wafer and a compound layer, wherein the compound layer is a sol-gel layer, producible from the monomers Si(OR1)4, (1) and one, two, or all of the following monomers Si(OR1)3R2, (2) Si(OR1)2R3R4 (3) and Si(OR1)R5R6R7 (4) wherein each R1 independently represents H or a C1-C8 alkyl group, R2, R3, R4, R5, R6 and R7 each independently represent a C1-C 20 -Alkyl group, a fluorinated C1 - C 20 -Alkyl group, a C1 - C 20 -Aminoalkyl group, a C2-C 20- an alkenyl group, an aryl group, a fluorinated aryl group, a singly, doubly or triply C1-C4 alkylated aryl group, wherein the alkylations are independent of each other with respect to their number of carbon atoms and / or wherein the group may also be fluorinated, or a C3-C 20 -Represent epoxy residue.

[0016] Preferably, a wafer comprises electronic components on its front side, wherein this front side is protected by the interconnect layer to be used according to the invention.

[0017] A wafer-support arrangement is preferred according to the invention, wherein in the compound layer each H or a C1-C5 alkyl group is independent of the others and / or R2, R3, R4, R5, R6 and R7 each independently represent a C1-C8 alkyl group, a fluorinated C1-C8 alkyl group, a C1-C8 aminoalkyl group, a C2-C8 alkenyl group, an aryl group, a fluorinated aryl group, a singly, doubly or triply C1-C4 alkylated aryl group, wherein the alkylations are independent of each other with respect to their number of carbon atoms and / or wherein the group may also be fluorinated, or a C3-C8 epoxy group.

[0018] Preferred solvents for the preparation of the compound layer are selected from the group consisting of alcohols, in particular methanol, ethanol, propanol, butanol, pentanol, water, aprotic solvents, in particular PGMEA (1-methoxy-2-propyl acetate), acetone, or ethyl acetate. Particularly preferred solvents are selected from the group of alcohols, in particular 2-propanol and 2-methyl-1-propanol.

[0019] Preferred activators for the sol-gel reaction in the synthesis of the compound layer are selected from the group consisting of acids and bases, in particular TMAH (tetramethylammonium hydroxide), formic acid, hydrochloric acid, and sulfuric acid. Further preferred activators are Lewis acids or bases, organometallic compounds such as tributyltin, or fluoride-containing compounds such as TBAF (tetrabutylammonium fluoride) or cesium fluoride. TMAH, TBAF, and sulfuric acid are particularly preferred activators.

[0020] It is particularly preferred that in the compound layer according to the invention each R1 independently represents H or a C1-C3 alkyl group and / or R2, R3, R4, R5, R6 and R7 each independently represent a C1-C3 alkyl group or a fluorinated C3 alkyl group.

[0021] Surprisingly, the wafer-support arrangement according to the invention can be separated very easily and, above all, without significant mechanical stress on the wafer. It is possible, for example, to remove the sol-gel layer chemically after separation.

[0022] The sol-gel layer used according to the invention has the advantage that sol-gel layers in general can be adapted to specific requirements with regard to their properties. Sol-gel layers that are temperature-resistant up to 450°C ≤ without chemical change are preferred. The sol-gel layer used according to the invention is silicon-based and therefore highly compatible with elastomers, especially silicon-based elastomers. Furthermore, the compound layer used according to the invention is cost-effective and non-toxic. After polymerization, the sol-gel layer remains chemically stable over a long period. Due to the monomers used, it can be readily integrated into typical wafer manufacturing processes, as it can be produced, for example, from a liquid.

[0023] The stoichiometric ratio of the monomers (1) to the sum of the stoichiometric ratios of the monomers (2), (3) and (4) in the wafer-support arrangement according to the invention is 0.032 (1 : 31.25) to 1.6 (1.6 : 1); preferably 0.05 to 1 (1 : 20 to 1 : 1) and particularly preferably 0.064 to 0.5 (1 : 15.63 to 0.5 : 1).

[0024] With these material ratios, especially the preferred variants, particularly suitable compound layers for the wafer-support arrangements according to the invention can be created.

[0025] A wafer-support arrangement according to the invention is preferred, in which the layer thickness of the compound layer is 10 to 200 nm, preferably 20 to 150 nm and particularly preferably 30 to 100 nm.

[0026] The preferred layer thicknesses allow for a particularly stress-free separation of the support system from the wafer.

[0027] A wafer-support arrangement according to the invention is preferred, wherein the elastomer layer is an organosilicon layer.

[0028] Preferably, the elastomer layer (i.e., a layer consisting of elastomer) is a layer consisting of a material selected from the group consisting of

[0029] Methyl, phenyl, epoxyalkyl, epoxyarylalkyl silicone or silicone with mixed functionalities, e.g. methylphenyl silicone; (catalytically) crosslinked silicone elastomer via alkyl groups with at least one of the aforementioned functionalities and their mixtures with silicone resins, all with or without fillers.

[0030] Preferably, the elastomer layer has a Shore A hardness of 40 to 100, more preferably 45 to 90, more preferably 50 to 80, and particularly preferably 55 to 75. The Shore hardness is determined according to DIN 53505-A-87.

[0031] In the wafer-support arrangement according to the invention, the area with the lowest adhesive force in the arrangement is the interface between the compound layer and the elastomer layer. This is also the preferred area along which separation occurs during an adhesive force determination according to measurement example 1.

[0032] The adhesive strength (bonding strength) between the respective layers can be determined by a specialist according to DIN EN ISO 4618:2007-03, and is defined as "the total bonding forces between a coating and its substrate". Preferably, the adhesive strength between the layers that create the area of ​​lowest adhesive strength (as the interface) is determined according to measurement example 1.

[0033] The advantage of this particularly preferred wafer-support arrangement according to the invention lies in the fact that, due to the properties of the elastomer material (flexibility, extensibility), an ideal bond can be established between the elastomer layer and the compound layer on the wafer. In particular, the adhesive strength between the compound layer and the elastomer layer can be achieved such that, upon separation of the wafer-support arrangement according to the invention, the elastomer material is completely detached from the compound layer. This separation is preferably carried out mechanically.

[0034] A wafer-support arrangement according to the invention is preferred, wherein the wafer comprises electronic components on the side facing the bonding layer (front side).

[0035] A wafer-support arrangement according to the invention is preferred, wherein the support is a glass plate or a second wafer.

[0036] By selecting a suitable glass plate or wafer, it is possible to match the coefficients of thermal expansion of the support and the wafer to be processed (the first wafer) so that no stresses or only very low stresses arise in the wafer-support arrangement according to the invention, even when the system is heated or exposed to heat generation due to mechanical loads.

[0037] This document also describes a coated wafer of a wafer-support arrangement according to the invention, wherein the coating is a bonding layer as defined above.

[0038] This coated wafer can be used as a precursor for the wafer-support arrangement according to the invention by applying a support system, as defined above, to the bonding layer.

[0039] A coated wafer of this type is preferred, wherein the compound layer on the side facing away from the wafer has a static water contact angle of ≥ 80°, preferably ≥ 83°, and / or a surface energy of 15–25 mJ / m². 2 exhibits .

[0040] Furthermore, this document also describes the use of a compound layer as defined above for the production of a wafer-support arrangement according to the invention or a coated wafer described above.

[0041] Part of the invention further comprises a method for processing the back side of a wafer, comprising the steps: a) Providing a wafer-support arrangement according to the invention, b) Processing the back side of the wafer and c) mechanical separation of the wafer-support assembly along the interface between the elastomer layer and the compound layer.

[0042] Processing the back of the wafer can include, in particular: metallizing, thinning TSV (Through silicon via contacting), lithography techniques.

[0043] The mechanical separation for the inventive method is preferably carried out as follows: The wafer-support assembly is fixed on both sides using vacuum or mechanical means. The flexible fixation on the support side is lifted starting from one side, thereby detaching the support from the wafer. This process is carried out as described in WO 002010072826 A2, in particular as shown in the Fig. 3 and the accompanying text.

[0044] A preferred method according to the invention is wherein, after step c), the compound layer is chemically removed from the wafer.

[0045] This chemical removal can, in principle, be carried out with any suitable agent. It is important to ensure that the bonding layer is reliably removed while the wafer, and especially any electronic components that may be located on the wafer, are not damaged.

[0046] Suitable agents for the chemical removal of the compound layer include strong acids and alkalis, as well as compounds that provide fluoride ions, such as TBAF, CsF, HF or KHF2.

[0047] Tetrabutylammonium fluoride (TBAF) is particularly preferred for the chemical removal of the compound layer.

[0048] TBAF is known for a variety of applications, but not previously for the specific application proposed here. For example, TBAF is known as an agent for removing silyl-containing protecting groups, as an activator / catalyst in the production of sol-gel systems, as a silicone remover, and as a phase-transfer catalyst. Its applicability to sol-gel layers, particularly in connection with the present invention, has not been previously known.

[0049] To set a suitable surface energy for the compound layer, the person skilled in the art will take one or more of the following measures.

[0050] The ratio of pure structure-forming agent, such as tetraethyoxysilane (TEOS), to the silane modified with alkyl groups (modifier), such as methyltrimethoxysilane or phenyltrimethoxysilane, largely determines the surface energy and thus the resulting adhesive forces of the interlayer and the elastomer. The higher the proportion of modifier, the lower the surface energies that can be achieved. Replacing or supplementing the modifiers with silanes containing large alkyl groups, such as hexadecyltrimethoxysilane or fluorinated alkyl groups, can further reduce the surface energies.

[0051] By selecting a suitable activator and its quantity, both the activation time of the mixture and its storage stability can be influenced. The lower the activator concentration, the longer the mixture takes to activate, but the storage stability is also significantly increased. Reducing the amount of activator also affects the resulting surface energies: adding less activator lowers the surface energies. The choice of activator also influences the resulting adhesive forces; these increase by up to 35% for acid-based activators, such as sulfuric acid, compared to TMAH-based activators. In contrast, the adhesive forces hardly change when TMAH is replaced equimolarly by TBAF. Mineral and organic acids, mineral and organic bases, Lewis acids and bases, and fluoride-releasing compounds can be used as activators.

[0052] The temperature during the curing of the bonding layer also plays a role. If the temperature is too low, insufficient cross-linking occurs, and the resulting adhesive forces are too high for a smooth separation of the substrate and device wafer. The adhesive force reaches a minimum at approximately 165°C and then increases slightly again above 200°C.

[0053] The Fig. Figure 1 schematically illustrates the creation of a wafer-support arrangement according to the invention: The reference numerals mean: 1 wafer (possibly with electronic components) 2 Compound layer precursor (liquid) 3. Bonding layer 4 Elastomer (not yet cured) 5 elastomer layer 7 carriers

[0054] The Fig. Figure 2 schematically illustrates the separation of a wafer-support arrangement according to the invention. The reference numerals have the same meaning as in Figure 2. Fig. 1.

[0055] Additionally, the reference symbol means 9 Second carrier.

[0056] In Fig. 1a) First, the wafer 1 is coated on its front side with liquid monomers 2 for the bonding layer 3 (sol-gel layer). The material 4 for the elastomer layer 5 is initially still liquid.

[0057] In step b) of Fig. 1. The sol-gel layer 3 is created by cross-linking. This usually happens through the application of heat.

[0058] Fig. 1c) represents the wafer-support arrangement 1, 3, 5 according to the invention in its finished form, in which, starting from Fig. 1b) First, material for the elastomer layer 4 was applied. Subsequently, the carrier 7 was placed onto the not yet (fully) cured elastomer layer and then cured into the material for the elastomer layer 4 to form the elastomer layer 5.

[0059] In Fig.2a) The already thinned wafer 1 is applied to a second support 9. The support 7 and the elastomer layer are prepared according to Fig. 2b) mechanically separated from the bonding layer. In Fig. Figure 2c) schematically illustrates that the bonding layer 3 is chemically removed from the wafer (cleaning). Simultaneously, the support 7 can also be chemically cleaned of the residues of the elastomer layer 5. Examples Measurement examples Measurement example 1: Determination of the adhesive force between the bonding layer and the elastomer layer

[0060] The according to Fig. 1c) The connected wafers are placed in an apparatus and arrangement according to Fig. 3 inserted and fixed to the upper and lower mounting plates using a vacuum. In Fig. 3 means: 1 Upper mounting plate 2 Upper vacuum supply 3 carriers 4 Elastomer 5 Device wafers with bonding layer (diameter 300 mm) 6 Lower vacuum plate 7 Lower mounting plate 8 Endpoint 9 Vacuum supply

[0061] The upper mounting plate is flexible and made of polycarbonate, trade name Makrolon®, Bayer AG, with a modulus of elasticity of 2.2–2.4 GPa. The plate is 5 mm thick, 340 mm wide, and 400 mm long. The mounting plate is positioned so that the force is applied to the longer side, which extends beyond the wafer (300 mm diameter).

[0062] Before measuring the force, the wafer stack is separated by lifting the free end of the upper holding plate in the direction of the arrow until it reaches the wafer halfway, so that the separation front, which now runs transversely across the wafer, has its maximum length. As the separation front continues to move, the effective free lever arm length increases, and consequently, so does the force measured at the measuring point along the direction of the arrow. The maximum measured tensile force is used as the measured value, which, based on experience, results in an effective lever arm length of approximately 245 mm. The point of force application on the lever arm is 95 mm from the wafer edge. For wafers with a diameter other than 300 mm, the adhesive force determination is converted to a 300 mm diameter wafer, taking into account both the changed lever arm length and the changed length of the separation front. Measurement example 2: Determination of the water surface angle

[0063] The static water edge angle is determined according to DIN 55660-2:2011-12. Measurement example 3: Determination of surface energy

[0064] The surface energy (free surface energy) is determined according to DIN 55660-2:2011-12. Measurement example 4: Determination of the water roll-off angle

[0065] The wafer is fixed to a tilting plate. A water droplet (deionized and particle-filtered (0.22 µm), Waters-Millipore, Milli-Q), either 50 µL, 25 µL, or 10 µL, is then applied to the wafer. The angle at which the water droplet begins to move slowly is determined. A total of three measurement runs are performed for each droplet size. Preferred values ​​range from 10–13° for 50 µL water droplets, and / or 18–25° for 25 µL droplets, and / or 28–55° for 10 µL droplets on the cured compound layers.

[0066] In case of doubt, the water roll-off angle is determined, as described in this measurement example, especially for 25 µL. Examples of implementation Example 1: Isopropanol (IPA, 99.8% Carl Roth) (97.75 vol%), tetraethoxysilane (TEOS, ≥99.0%, Sigma-Aldrich) (0.5 vol%), and methyltrimethoxysilane (MTMS, ≥98.0%, Sigma-Aldrich) (1.5 vol%) are mixed. Then, the activator (Brønsted or Lewis acid, base, or fluoride ion donor), in this case 0.25 vol% tetramethylammonium hydroxide (TMAH 2.38 wt% in H₂O, Micro Chemicals), is added. - The activity is checked by a dip-coat before use. For this, an elongated (approx. 1 x 5 cm) section of a new, untreated silicon wafer is briefly immersed in the solution. If a layer forms when the precursor dries, the solution is suitable for spin-coating. The activation time ranges from a few minutes to several days, depending on the concentration and activator content. - The wafer to be treated is completely covered with precursor (approx. 10 mL for a 200mm wafer, approx. 20 mL for a 300mm wafer) and after standing for about 30 seconds, spun at 1000 rpm for 20 seconds. - The still-moist layer is then annealed at 165°C for 10 minutes, reducing the layer thickness from an initial 60-80 nm to 40-60 nm, and the layer solidifies. The water roll-off angle (50 µL drop) is now 10-13°, and the water contact angle (10 µL drop, static) is 95-105°. - A second silicon wafer is coated with addition-curing silicone adhesive, and in the bonding chamber at reduced pressure (about 0.3 mbar) both wafers are joined by "forcefree bonding" (as described in WO 2010 / 061004 A1). - After 10 minutes of curing of the silicone adhesive, the wafer stack can be subjected to further processes. - To separate the wafer stack, a small portion of the wafer is detached from the rest of the process at one point. The lower wafer, fixed to a vacuum plate, is then separated using a second vacuum plate. The sol-gel layer remains on the device wafer; the separation occurs between the sol-gel release layer and the silicone adhesive. - To remove this layer, the wafer is immersed in a solution of 2.5 wt% tetrabutylammonium fluoride (TBAF, 97%, Sigma-Aldrich) in methyl isobutyl ketone (MIBK) for 10-20 minutes using agitated dipping and then washed with isopropanol. Alternatively, a wafer coated with a sol-gel layer is cut into 4 x 4 cm pieces, and these pieces are placed in the etching solution (static dipping). The values ​​for static dipping are lower than those for agitated dipping and cannot be directly compared. The coating is resistant to organic solvents such as acetone, isopropanol, MIBK, and gasoline; but also to water, aromatic hydrocarbons, and chlorinated hydrocarbons. Only the combination of an organic solvent and the etching agent dissolved in it (TBAF) leads to its removal. Example 2: Alternative mixture for the bonding layer - 94.15% by volume IPA - 2.5% by volume TEOS - 2.5 vol.% MTMS - 0.6% by volume water (H2O) - 0.25 vol.% hydrochloric acid (HCl) aq , 0.95 wt% diluted from 1M standard solution, Carl Roth) Example 3: Alternative mixture for the bonding layer - 97.25 vol.% isopropanol - 0.5% by volume TEOS - 1 vol.% MTMS - 1% by volume hexadecanetrimethoxysilane (HDTMS, ABCR Research Chemicals) [16415-12-6] or 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FAS, ABCR Research Chemicals) () [51851-37-7] - 0.25 vol.% TMAH

[0067] The chemicals in Examples 2 and 3 are the same as those in Example 1, unless otherwise specified. Example 4: Water surface angle

[0068] According to measurement examples 2 and 3, the following values ​​were measured for the layers from examples 1 to 3 after curing (Table 1) Water surface angle [°] 50 µL Water roll angle [°] 25 µL 10 µL Example 1 84 12 21 40 Example 2 80 13 25 52 Example 3 91 11 22 48 Example 5: agitated dipping:

[0069] The 300 mm diameter wafer, coated with a sol-gel layer, is fixed to a vibrating plate, and 300 mL of cleaning solution is incubated. The cleaning solutions used are the Fig. 4. Before and after the cleaning procedure, the thickness of the sol-gel layer is determined using an interferometer; the etch rate is calculated from the exposure time and the decrease in layer thickness. Etching rate = layer thickness reduction / time Definitely. It has been found that, in general, TBAF-containing solutions are preferable as cleaning agents. Example 6: static dipping

[0070] A 4 x 4 cm wafer coated with a sol-gel layer is placed in 50 mL of etching solution. The solution is not agitated. The etch rate is determined according to the equation given in Example 5. Due to the lack of agitation, the etch rates are lower than with agitated dipping (Example 5).

Claims

Wafer-support arrangement comprising: - a wafer, - a support system comprising a support and an elastomeric layer, wherein the elastomeric layer is oriented towards the wafer, and - a compound layer, wherein the compound layer is a sol-gel layer, fabricable from the monomers (1) Si(OR1)4, and one, two, or all of the following monomers: (2) Si(OR1)3R2, (3) Si(OR1)2R3R4, and (4) Si(OR1)R5R6R7, wherein each R1 independently represents H or a C1-C8 alkyl group, R2, R3, R4, R5, R6, and R7 each independently represent a C1-C20 alkyl group, a fluorinated C1-C20 alkyl group, a C1-C20 aminoalkyl group, a C2-C20 alkenyl group, an aryl group, a fluorinated aryl residue, a singly, doubly or triply C1-C4 alkylated aryl residue, wherein the alkylations are independent of each other with respect to their number of carbon atoms and wherein the residue may also be fluorinated, or represent a C3-C20 epoxy residue,wherein the stoichiometric ratio of the monomers (1) to the sum of the stoichiometric ratios of the monomers (2), (3) and (4) is 0.032 (1 : 31.25) to 1.6 (1.6 : 1) and the area with the lowest adhesive force in the arrangement is the interface between the compound layer and the elastomer layer. Wafer support arrangement according to claim 1, wherein the stoichiometric ratio of the monomers (1) to the sum of the stoichiometric ratios of the monomers (2), (3) and (4) is 0.05 to 1 (1 : 20 to 1 : 1) and particularly preferably 0.064 to 0.5 (1 : 15.63 to 0.5 : 1). Wafer support arrangement according to claim 1 or 2, wherein the thickness of the compound layer is 10 to 200 nm, preferably 20 to 150 nm and particularly preferably 30 to 100 nm. Wafer support arrangement according to one of the preceding claims, wherein each R1 independently represents a C1-C3 alkyl group and / or R2, R3, R4, R5, R6 and R7 each independently represent a C1-C3 alkyl group, a fluorinated C1-C3 alkyl group, a C2-C3 alkenyl group or phenyl group. Wafer support arrangement according to one of the preceding claims, wherein the elastomer layer is an organosilicon layer. Wafer support arrangement according to one of the preceding claims, wherein the wafer comprises electronic components on the side facing the compound layer. Wafer support arrangement according to one of the preceding claims, wherein the support is a glass plate or a second wafer. Wafer-support arrangement according to one of the preceding claims, wherein the adhesive force between the compound layer and the elastomer layer is ≤ 300 N / m, preferably ≤ 100 N / m at a tensile speed of 0.1 mm / s in each case. Method for processing the back side of a wafer, comprising the steps: a) providing a wafer-support assembly according to any one of claims 1-8, b) processing the back side of the wafer, and c) mechanically separating the wafer-support assembly along the interface between the elastomer layer and the compound layer. Method according to claim 9, wherein after step c) the compound layer is chemically removed from the wafer.

Images