Method and substrate system for separating a carrier substrate - Patents.com

Abstract

The present invention relates to a method and a substrate system for separating a carrier substrate from a substrate, in particular a product substrate, by irradiation of a separation layer.

Description

[Technical field]

[0001] The present invention relates to a method, an apparatus and a substrate system for separating a carrier substrate from another layer.The carrier substrate can be separated in different methods for processing a substrate, for example during debonding or transfer of the substrate.

[0002] In the semiconductor industry, it is becoming increasingly important to develop methods and devices which, on the one hand, can produce high adhesion between surfaces and, on the other hand, can eliminate adhesion again if necessary. Such methods and devices for processing substrates are used in particular for two different techniques: layer transfer and bonding or debonding of substrates.

[0003] In layer transfer, particularly inorganic, often very thin layers that are not mechanically stable per se are transferred between self-supporting substrates. The inorganic layer is formed, for example, on a special growth substrate, but then needs to be transferred onto another substrate, in particular a product substrate, where it can fulfill its functional properties. The growth substrate and the product substrate are very rarely identical.

[0004] In the prior art, so-called release or separation layers are used to effect a locally targeted separation of the useful layer from the carrier substrate. To date, organic polymer layers have been used as bonding layers, which require additional, laborious cleaning steps during the transfer of the useful substrate and increase contamination.

[0005] During bonding and debonding of substrates, two substrates are first bonded to one another, so that one of the two substrates, which usually does not have sufficient internal stability for the process due to its relatively small thickness or strength, can be supported and processed by the second substrate. The processed substrate is called the product substrate, the supporting substrate is called the carrier substrate. To form so-called temporary bonds, i.e. non-destructively peelable bonds, polymers are mainly used. For this purpose, at least one polymer is applied to the substrate by a method, in particular a spin-coating method. The carrier substrate is mainly coated with a polymer (separation layer) and the carrier substrate is bonded to the product substrate. After bonding the product substrate to the carrier substrate, the product substrate is further processed in order to be separated again from the carrier substrate in a later method step. Various methods exist in the prior art for separating the carrier substrate.

[0006] In recent years, the carrier substrate has often been coated all over with a polymer. This results in a very good adhesion between the carrier substrate and the product substrate. If the product substrate has bumps, e.g. solder balls, dies or chips, these bumps can be embedded in the polymer, provided that the polymer layer acting as a separation layer has a corresponding layer thickness. A disadvantage of this method appears when peeling the carrier substrate from the product substrate. For separation, the polymer layer must be acted on all over, so that complete separation is performed in a laborious manner, especially with several processing steps. The adhesion of the adhesion layer can be reduced by chemicals which reach the adhesion layer laterally or through the carrier substrate, until mechanical separation is possible. The action of the chemicals on the adhesion layer is preferably performed at high temperatures.

[0007] Furthermore, the detachment of the entire polymer layer also results in higher energy (e.g., heat, ultrasound) or solvent demands during removal of the deposited material, and thus higher costs. The detachment itself is controlled in this process by a peel force, preferably perpendicular to the substrate surface.

[0008] An alternative refinement is the so-called "slide-off debonding". In this method, a device is used in which the product substrate and the carrier substrate are each fixed in position over their entire surface by a substrate holder. The two substrate holders are then moved parallel to each other, so that the substrates are sheared against each other along the adhesion surface via forces. For this purpose, it is necessary to heat the polymer layer located between the substrates. This softens the polymer layer and causes it to lose its adhesion strength. The advantage of this method is that solvents and ultrasound can be completely omitted. The disadvantage is that the debonding still has to be carried out at high temperatures.

[0009] An alternative method for debonding omits the use of high temperatures and uses only a solvent acting on the polymer from the periphery of both substrates. The action of the solvent can be accelerated by ultrasound. The dissolved polymer is preferably carried out of the substrate stack by circulation of the solvent and is preferably continuously removed from the solvent bath. It is also possible to simply spray the solvent laterally towards the polymer and remove it by solvent radiation.

[0010] A variant of the solvent process is the so-called ZoneBond® process, described in WO2009094558. This is a method in which the carrier substrate must be specially prepared. The carrier substrate has two zones that are different from each other. The central zone, which occupies the largest area, is coated with an anti-sticking layer and has low adhesion to any kind of polymer. The second zone surrounds the first zone circularly, mainly as a closed ring, and reaches up to the periphery of the carrier substrate. The ring thickness is only a few millimeters. This extremely small area is sufficient for fixing the polymer and thus the product substrate bonded to the carrier substrate all over. The inner side is fixed during the processing steps by air pressure and by sealing the sides. Advantageously, for debonding, the polymer only has to be removed from the more easily accessible second zone, which allows debonding of the carrier substrate from the product substrate.

[0011] Another improvement is the use of a photosensitive separation layer. This photosensitive separation layer is often applied on a carrier substrate, particularly a transparent one. The carrier substrate is then coated with a polymer layer and the carrier substrate is bonded to the product substrate. After the product substrate has been processed to the end, the carrier substrate can be peeled off from the product substrate by irradiating the separation layer through the carrier substrate. Such methods are described, for example, in US20150035554, US20160133486 and US20160133495. A special embodiment of this method, in which the separation layer is applied on the product substrate and not on the carrier substrate, can be found in WO2017076682.

[0012] The above-mentioned methods can be combined with each other. For example, a reorientation of the product substrate can also be performed. In this method, the carrier substrate is exchanged, which is also called carrier flip. For example, WO 2011120537 shows a method in which the product substrate is fixed on a first carrier by a polymer layer and then processed. After processing, in particular after backside thinning, the product substrate is very thin and is bonded onto a second carrier substrate for further use of the other substrate side. The transfer to the product substrate is carried out via two polymer layers. In this case, the first carrier substrate has to be separated from the product substrate after fixing of the product substrate on the second carrier substrate.

[0013] All of the methods described are mostly based on influencing some component, in particular a layer, so that its adhesion to another component is reduced, in particular completely eliminated, i.e. the adhesive properties of the separating layer are reduced.

[0014] Thus, the devices and methods described in the prior art describe separation processes in which an organic layer, in particular a polymer layer, is provided as a separation layer or an organic bonding layer is combined with an inorganic separation layer. The use of polymers as a bonding and / or separation layer that temporarily bonds two substrates to each other has several disadvantages. Polymers are long-chain molecules whose main component is carbon. Organic materials are disadvantageous and often undesirable in the semiconductor industry because they can contaminate the cleanroom environment, in particular the equipment in which the substrates are processed. Furthermore, polymers have the disadvantage of only maintaining their adhesion properties up to relatively low temperatures, which is an advantage for debonding, but a disadvantage when the product substrate on the carrier substrate has to be processed at high temperatures. Besides the low thermal resistance of the organic layer, the organic separation layer often has to be deposited relatively thickly in order to provide the corresponding adhesion properties.

[0015] However, in addition to the problems during debonding, in the prior art there is also the problem of transferring the layers formed on the substrate onto the product substrate, since for this purpose also a separation layer is used to separate the formed substrate stack from the carrier substrate.

[0016] These different methods are characterized in that, on the one hand, they require high holding forces during processing, independent of the process temperature, and, on the other hand, the substrates must be separated from one another after processing with as little force as possible.

[0017] It is therefore an object of the present invention to provide a method for separating a carrier substrate and a substrate system for processing and transferring a substrate, which at least partially, in particular completely, eliminates the drawbacks mentioned in the prior art. In particular, it is an object of the present invention to provide an improved method and an improved substrate system for separating a substrate or for separating a layer provided on a substrate. Furthermore, it is an object of the present invention to provide an alternative method and an alternative substrate system, with which a substrate can be simply and cleanly processed, in particular debonded or transferred. It is further an object of the present invention to provide a method and a substrate system which operates with or allows for operation with low contamination. Furthermore, it is an object of the present invention to provide a substrate system, in particular in which the carrier substrate is particularly easily separable or peelable.

[0018] This problem is solved by the features of the parallel independent claims. Advantageous refinements of the invention are defined in the dependent claims. All combinations of at least two features described in the description, claims and / or drawings are also within the scope of the invention. In the described numerical ranges, values ​​within the stated ranges are also considered as disclosed as limit values ​​and can be claimed in any combination.

[0019] The present invention therefore relates to a method for separating a carrier substrate from a product substrate, the method comprising at least the steps of: i) providing a carrier substrate and a product substrate with a release layer disposed between the carrier substrate and the product substrate, the release layer fixing the product substrate in position on the carrier substrate; ii) irradiating the separation layer with a laser beam from a laser unit; iii) separating the carrier substrate from the product substrate; having The separating layer is inorganic.

[0020] The release layer simultaneously functions as a bonding or adhesive layer, in particular for temporarily fixing the carrier substrate to the product substrate. The product substrate can be a substrate stack, a component or an individual functional layer. In that respect, the separation method is also basically defined for separating any further substrate from the carrier substrate. Particularly preferably, the release layer is arranged directly on the carrier substrate. This advantageously makes it possible to dispense with a further bonding layer.

[0021] Furthermore, during the separation process, preferably no further layers, in particular organic layers, are required in addition to the inorganic separation layer, thus advantageously reducing the degree of contamination.

[0022] Another embodiment of the method provides that at least one additional layer is disposed between the separation layer and the product substrate, and the at least one additional layer is inorganic.

[0023] In other words, the method advantageously allows processing of a substrate system comprising at least one carrier substrate, a separation layer and a further layer in such a way that the carrier substrate can be separated or peeled off from the at least one further layer by deliberate laser processing in a simple and low-contamination manner. In this case, in contrast to the prior art, a separation layer made of a carbon-free material is irradiated with a laser beam by means of a laser, which reduces the adhesion properties of this inorganic separation layer, while the further layer is likewise inorganic. The release of the carrier substrate by acting on the inorganic separation layer allows a completely inorganic layer structure of the substrate system. Thus, advantageously, the use of organic separation or bonding layers can be omitted in different methods of processing substrates, especially during debonding and transfer of the substrate.

[0024] The higher heat resistance of inorganic materials allows for more flexible process design, and inorganic separation and bonding layers typically have good thermal conductivity, allowing for better heat dissipation through the carrier substrate.

[0025] Furthermore, polymer-based organic separation layers and organic bonding layers can negatively contaminate the corresponding equipment and thus negatively affect the quality, so inorganic materials for the separation and bonding layers can reduce contamination of the equipment.

[0026] Furthermore, the high adhesion properties of the inorganic separation layer and / or bonding layer allow for thinner separation layers and thus for an overall thinner layer structure in the substrate system to be processed.The planarity of the substrate system can thus be improved and the amount of material to be processed, and thus contaminating, can be reduced.Another advantage of the method for separating the carrier substrate is that the energy input to the substrate system to be processed is relatively low and the corresponding thermal load is relatively low, so that particularly temperature-sensitive substrate systems can be processed.

[0027] The separation layer is formed from a carbon-free material and is in particular pre-deposited on the carrier substrate, to the extent that the separation layer can also simultaneously serve as a bonding layer (temporary bonding) for bonding to the product substrate via at least one further layer.

[0028] Here, the carrier substrate can be understood to be any substrate suitable for the application of an inorganic separation layer. Preferably, the carrier substrate is an inorganic substrate, particularly preferably a silicon wafer. Particularly preferred is a silicon wafer.

[0029] The laser unit acts on the separation layer in different, preferably regularly spaced areas with deliberate and adjusted parameters. The inorganic separation layer, which is preferably non-transparent to the laser beam of the laser unit, absorbs the laser beam, which locally reduces the adhesion properties and / or stability of the separation layer. In particular, due to the high local energy concentration, lateral cracks are generated in the separation layer, which allows the carrier substrate to be easily peeled off from at least one further layer or from the product substrate. The inorganic separation layer then allows the carrier substrate to be deliberately separated from at least one further layer in the case of this separation method.

[0030] Even if it is not preferred, a particularly continuous, large-area laser incidence is possible, in which the laser beam does not move relative to the substrate and is expanded to impinge on the substrate all over. In particular, in such a special embodiment, the exposure time must be selected to be rather long.

[0031] In one preferred embodiment of the method, it is provided that an exclusively inorganic layer is arranged between the product substrate and the carrier substrate, which allows the method to be carried out with particularly low contamination.

[0032] In a preferred embodiment of the method, during irradiation in step ii), the laser beam emitted by the laser unit first penetrates the carrier substrate and then strikes the separation layer. In other words, the laser beam first passes through the carrier substrate and then is absorbed by the separation layer. The carrier substrate is therefore at least partially transparent to the laser beam. The laser unit can therefore be advantageously arranged on the rear side of the carrier side, and separation can be flexibly performed from the rear side without imposing special requirements on the product substrate. In this connection, it is to be noted that the at least one further layer, which is optionally provided, also absorbs the laser beam so strongly that in each case the product substrate is advantageously protected.

[0033] In a preferred embodiment of the method, the at least one further layer is a silicon oxide layer that acts as an adhesion layer, this inorganic adhesion layer allowing for a less contaminating separation process.

[0034] In a preferred embodiment of the method, at least one further layer is formed from a first oxide layer and a second oxide layer, in particular by fusion bonding. This further layer, consisting of two oxide layers, is particularly suitable for simple and stable bonding.

[0035] In a preferred embodiment of the method, it is provided that the separation layer is made of a metal or a nitride, preferably TiN. Inorganic separation layers made of metals or nitrides are particularly suitable, since they also allow for particularly stable bonding. Tin-based separation layers are particularly preferred.

[0036] In a preferred embodiment of the method, the laser beam has a wavelength of 0.1 μm to 500 μm, preferably 0.2 μm to 100 μm, more preferably 0.3 μm to 50 μm, more preferably 0.5 μm to 10 μm, most preferably 1 μm to 2.5 μm. This allows a particularly efficient and targeted irradiation of the separation layer. The carrier substrate is preferably transparent to the laser beam.

[0037] In a preferred embodiment of the method, the pulse energy of the laser beam is set to 0.01 μJ to 128 μJ, preferably 0.125 μJ to 64 μJ, more preferably 0.25 μJ to 32 μJ, even more preferably 0.5 μJ to 16 μJ, and most preferably 1 μJ to 8 μJ. It has been found that these pulse energies can avoid damage to the product substrate.

[0038] In a preferred embodiment of the method, the laser area is 2000 μm 2 Less than 500 μm, preferably 2 Less than 80 μm, more preferably 2 Less than 20 μm, more preferably 2 Less than 1 μm, most preferably 2 The area of ​​the separation layer acted upon by the laser is advantageously small, and can purposefully and locally reduce the adhesive properties of the separation layer or destroy it.

[0039] In a preferred embodiment of the method, the areas of action of the laser beam on the separating layer are located at least 0.1 μm, preferably at least 1 μm, even more preferably at least 5 μm, more preferably at least 10 μm, most preferably at least 50 μm apart, so that the areas of action of the laser beam do not overlap, which allows a particularly simple and efficient separation.

[0040] In a preferred embodiment of the method, the pulse width (duration) of the laser beam is 10000 ps to 1 ps, preferably 1000 ps to 1 ps, more preferably 500 ps to 1 ps, more preferably 100 ps to 1 ps, and most preferably 50 ps to 1 ps. This pulse width allows for deliberate action for separation.

[0041] Furthermore, the invention relates to a substrate system, in particular for the production of semiconductor components, which substrate system comprises at least A) a carrier substrate; B) a separation layer disposed on a carrier substrate; C) a product substrate disposed on the separation layer; It has the carrier substrate is separable from the product substrate by irradiation of the separation layer by a laser unit; The separating layer is an inorganic layer, and is characterized in that the separating layer fixes the product substrate in position on the carrier substrate.

[0042] In other words, the separation layer simultaneously serves as a bonding layer. Thus, simple and carbon-free structures are possible.

[0043] In a preferred embodiment of the substrate system, at least one further layer is disposed between the separation layer and the product substrate, and the product substrate is fixed in position on the carrier substrate by the at least one further layer, and the at least one further layer is inorganic.

[0044] This allows providing a further functional layer with optimal properties for the respective plan. Moreover, this further layer is inorganic, which further results in the advantages of a carbon-free or inorganic stack. If the further layer is a bonding layer, it is advantageous to adjust the adhesion properties between the carrier substrate / separation layer and the product substrate.

[0045] In a preferred embodiment of the substrate system, the at least one further layer is a bonding layer, which is formed from at least a first oxide layer and a second oxide layer, in particular by fusion bonding.

[0046] A preferred embodiment of the substrate system provides that an exclusively inorganic layer is arranged between the carrier substrate and the product substrate, which allows the substrate system to be processed independently of the need for a carbon-containing stack, and further reduces contamination.

[0047] In a preferred embodiment of the substrate system, it is provided that the separation layer has a separation layer thickness of 10 nm to 500 nm. A small separation layer thickness allows a particularly simple and efficient separation of the carrier substrate. Furthermore, it is advantageously possible to provide a particularly lightweight substrate system with a small thickness, while at the same time providing sufficient stabilization by the carrier substrate and position fixing by the separation layer or bonding layer.

[0048] By product substrate is understood any kind of movable component, in particular wafers, plates or also small individualized components such as chips, dies which differ in complexity, shape and function, e.g. LEDs, MEMS, etc. Carrier substrates are mostly wafers and are suitable for supporting layers arranged thereon.

[0049] In a particular embodiment, it is provided that on the inorganic separating layer there is an inorganic bonding layer, which is itself formed by fusion bonding of two separate inorganic layers, in particular made of an oxide, most preferably made of silicon oxide, while on this inorganic bonding layer there is another layer, particularly preferably a functional layer made of a semiconductor material. Since the inorganic bonding layer is made up of two layers, this bonding layer can be called a layer stack. Thus, another embodiment is in the order of the following elements: carrier substrate, inorganic separating layer, layer stack made up of at least two inorganic layers formed by fusion bonding, functional layer or product substrate.

[0050] Furthermore, the invention relates to an apparatus for separating a carrier substrate, which apparatus comprises at least a) a providing unit for providing a carrier substrate; b) a laser unit for irradiating a separation layer arranged on a carrier substrate, the at least one further layer being arranged on a side of the separation layer opposite the carrier substrate; and It has wherein the carrier substrate is separable from at least one further layer by irradiating the separation layer; The separating layer and the further layer are characterized in that they are inorganic.

[0051] The device is suitable for reducing the adhesive properties of an inorganic separation layer and thus for peeling or separating the carrier substrate of a substrate system. The laser unit, the material of the carrier substrate and the material of the separation layer are coordinated with each other. In particular, the use of a laser beam in the infrared range in conjunction with the preferred material combinations provides optimal results. The possibilities for optimal combinations of laser parameters and materials are shown in the present disclosure in tabular form as preferred embodiments.

[0052] An important aspect is that this method and device can destroy the inorganic layer or change the adhesive properties of the inorganic layer.The inorganic layer is used as a separation layer to separate two substrates / layers that are bonded to each other, or to peel off a layer that is arranged on the separation layer from a substrate or carrier substrate.Therefore, the substrate and the layer can be separated by the separation layer.The substrate with the separation layer can also be used to transfer another substrate / layer.

[0053] The method, the apparatus and the substrate system can be used for processing substrates, in particular for separating a product substrate from a carrier substrate, the term individual substrate also including a multi-layer substrate system or a multi-layer substrate stack.

[0054] An important aspect of the method and device for detaching a carrier substrate consists in depositing exclusively inorganic layers onto at least one carrier substrate, at least one of the inorganic layers being a release layer (English: release layer).

[0055] The separating layer is less than 10 μm, but typically less than 100 nm, suitably less than 50 nm, preferably less than 25 nm, more preferably less than 10 nm, most preferably less than 1 nm.

[0056] This separation layer is irradiated during separation of the substrate, in particular by a beam, in particular a laser beam or a comparable high-intensity electromagnetic radiation source, or a particle beam. Preferably, an electromagnetic beam, in particular a laser beam, is used, less preferably a particle beam.

[0057] The laser parameters preferably meet certain conditions in order to cleanly separate the layers of both substrates or separation layers arranged on the side opposite the carrier substrate from each other with a small load on the product substrate and the carrier substrate, preferably by optical influence on the inorganic separation layer. This advantageously allows the use of organic layers in the processable substrate to be completely omitted. In other words, the use of a highly heat-resistant inorganic separation layer allows processing steps that include a temperature range that would be unattainable for organic, and therefore less heat-resistant layers, especially polymer layers, without adversely affecting the retention force.

[0058] Another important aspect is to focus the energy of the laser on the separation layer in order to cause adhesion reduction and / or even the desired sublimation of the separation layer, which is caused by an additional gas pressure to push the layer apart beyond the irradiated area in the lateral direction, thereby allowing high efficiency during peeling, as long as the cohesive forces of the upper and lower bounded layers are higher than the adhesion of the adjacent materials, thereby allowing crack formation along the layer and not lateral crack formation relative to the layer. In this case, it is necessary to adjust the carrier substrate material, the surface properties of the carrier substrate, the laser wavelength, the laser energy and especially the duration of action (defined primarily by the laser pulse width in pulsed lasers). In the infrared and visible spectral ranges, in contrast to the ultraviolet spectral range, only very few efficient specific transfer processes occur that lead to molecular decomposition (photochemical dissociation) by direct interaction with chemical bonds, so that "cold chemical" separation is not easily possible. In this long-wave spectral range with low photon energy, nonlinear optical effects or short heat pulses are therefore used. The latter is kept intentionally short so that the heat propagation during the pulse interaction period is restricted as much as possible to the separation layer, so that the lateral restriction also prevents the heat from acting on the useful substrate in a high concentration, but is combined in the conversion process (e.g. in the gas phase) or distributed over a significantly larger volume and cross-sectional area before ejection, reducing the temperature by several orders of magnitude and without causing undesired damage to the substrate.

[0059] In particular, pulse widths in the one- to two-digit picosecond range are desirable, because for layer thicknesses of less than 1 μm this allows for the time capture of heat concentrations within the layer, while on the other hand this allows for the suppression of undesired nonlinear processes in the carrier substrate.

[0060] Another refinement of the method and the device describes the use of a purely inorganic bonding layer for bonding two substrates or layers in addition to the inorganic separation layer. The inorganic bonding layer is then arranged on the side of the separation layer facing away from the carrier substrate. The inorganic bonding layer allows a further distinction over the prior art, in which exclusively organic layers are used as bonding, and in particular no polymer layers are used as bonding layers. This allows the transfer of the substrate to be carried out cleanly, also at relatively high temperatures, since neither the separation layer nor the bonding layer consists of organic materials, in particular polymers, which tend to carbonize. In particular, the inorganic layer is characterized by an extremely high absorption (linear or nonlinear), which allows particularly thin layers or even more complex layer systems.

[0061] In this case, the substrate stack formed is preferably exclusively inorganic. Due to the inorganic structure, the substrate stack, in particular the product substrate, can be processed at very high temperatures. Another advantage is the relatively high adhesion strength between the two substrates or between the inorganic layers. Thus, the inorganic separation layer and possibly the inorganic bonding layer can be designed to be thinner. The inorganic material of the separation layer can thus be advantageously adapted to the various parameters of the laser unit. The laser unit can thus advantageously act on the separation layer in a targeted manner, without any or only minimal influence on the other layers and / or the carrier substrate.

[0062] The method of processing a substrate consists in at least partially removing, destroying or reducing the adhesion of an inorganic separation layer, thus allowing the transfer of another layer and / or the separation of a substrate, in particular a carrier substrate, from another substrate.

[0063] In some embodiments of the method, in addition to the inorganic separating layer, an inorganic bonding layer is used, which causes bonding of two substrates or layers.

[0064] The following paragraphs describe the parameter ranges within which the method can be performed or within which the apparatus operates.

[0065] The method is based on focusing the laser beam of a laser, in particular an infrared laser, onto the separation layer. The laser parameters must in particular fulfill some of the following criteria:

[0066] In the method and device for separating a carrier substrate, the following lasers or laser units are preferred: - In the ultraviolet spectrum, -F2, ArF, Nd:YAG, He-Ag, KrF, XeCl, He-Cd, XeF - In the visible spectrum, -He-Cd, Ar, copper vapor, He-Ne, Kr, Rubin - In the near infrared spectrum, -Nd:YAG, He-Ne, Er:Glass, Tm:YAG, Ho:YAG, Er:YSGG, Er:YAG - In the far infrared spectrum -Methanol, methylamine, methyl fluoride.

[0067] The wavelength of the laser beam emitted from the laser unit is 0.1 μm to 500 μm, preferably 0.2 μm to 100 μm, more preferably 0.3 μm to 50 μm, even more preferably 0.5 μm to 10 μm, and most preferably 1 μm to 2.5 μm.

[0068] Preferably, the following material classes and materials are used for the separating layer: Semiconductors, especially Ge Metals, especially Ti, W, Al, Ta, and Cu Nitrides, especially TiN, TaN, WN, W2N, WN2.

[0069] The laser or laser unit is preferably operated in a pulsed mode. Of particular importance is a pulse width as short as possible. A short pulse width results in localized heat introduction in the separation layer and sufficiently prevents heat conduction to other layers. The pulse width of the laser is 10000ps to 1ps, preferably 1000ps to 1ps, further preferably 500ps to 1ps, more preferably 100ps to 1ps, and most preferably 50ps to 1ps.

[0070] The laser spot size is the effective cross-sectional area of ​​the laser beam at the separation layer.

[0071] In the case where the laser face is circular, the laser area is preferably specified by the laser face diameter, which is less than 50 μm, preferably less than 25 μm, even more preferably less than 10 μm, more preferably less than 5 μm, and most preferably less than 1 μm.

[0072] If the laser face is square, the laser area is specified by the side length of the laser face, which is less than 100 μm, preferably less than 80 μm, even more preferably less than 50 μm, even more preferably less than 25 μm, and most preferably less than 15 μm.

[0073] When the laser faces are generally rectangular, the laser area is specified by the side length of the first laser face and the side length of the second laser face, the side length of the first laser face and / or the side length of the second laser face being less than 100 μm, suitably less than 80 μm, even more preferably less than 50 μm, more preferably less than 25 μm, and most preferably less than 15 μm.

[0074] The average laser area is 2000μm 2 Less than 500 μm, preferably 2 Less than 80 μm, more preferably 2 Less than 20 μm, more preferably 2 Less than 1 μm, most preferably 2 is less than.

[0075] Ignoring convergence, the laser area corresponds approximately to the laser beam diameter along a section of the laser beam.

[0076] The energy introduced per pulse is between 0.01 μJ and 128 μJ, preferably between 0.125 μJ and 64 μJ, more preferably between 0.25 μJ and 32 μJ, even more preferably between 0.5 μJ and 16 μJ, and most preferably between 1 μJ and 8 μJ. The corresponding laser areal energy density per pulse is calculated as the quotient of the energies per pulse relative to the laser surface.

[0077] The roughness of the carrier substrate surface affects the scattering of the laser beam, and preferably the roughness should be adjusted to allow a maximum amount of photons to penetrate into the carrier substrate.

[0078] Roughness is specified as average roughness, root mean square roughness or average roughness depth. Calculated values ​​for average roughness, root mean square roughness and average roughness depth generally differ from each other for the same measurement distance or area, but are within the same order of magnitude. Thus, the following numerical ranges for roughness can be interpreted as either average roughness, root mean square roughness or average roughness depth values.

[0079] The roughness is greater than 10 nm, suitably greater than 100 nm, even more preferably greater than 1 μm, more preferably greater than 10 μm, most preferably greater than 100 μm.

[0080] The distribution of the laser surface energy along the position is not necessarily uniform. The laser surface energy is specifically characterized by one of the following distribution functions: Gaussian distribution, Cauchy distribution, Lorentz distribution, Pearson distribution, or Uniform distribution.

[0081] Another important aspect of the method for separating the carrier layer is the nonlinear optical effects that occur upon irradiation of the separation layer by a laser unit.

[0082] By means of a suitable combination of suitable physical parameters, in particular the carrier substrate material, the pulse length, the laser wavelength and the laser energy, the behavior of the electromagnetic waves or photons in the carrier material can be adjusted in such a way that focusing of the laser beam in the separation layer is achieved, for which the optical properties of the material, in particular the electro-optical Kerr effect, which describes the change in the refractive index as a function of the electric field strength, plays a decisive role.

[0083] The selected laser parameters and the resulting spatially focused, short duration, high energy energy input produce at least one of the following physical effects:

[0084] The extreme temperature increase results in thermal expansion between the separation layer and at least one other layer or substrate adjacent to the separation layer. This effect is more efficient the greater the difference in thermal expansion coefficient between the separation layer and the adjacent layer or substrate. The expansion coefficient is temperature dependent, but can be as low as 10 -6 K -1 The absolute value of the difference between the coefficient of expansion of the separating layer and the coefficient of expansion of at least one other adjacent layer or at least one adjacent substrate is in the order of 0.1. * 10 -6 K -1 Larger, preferably 1.0 * 10 -6 K -1 Greater than 2.5, preferably * 10 -6 K -1 Greater than 5.0, preferably * 10 -6 K -1 Greater than, most preferably 10.0 * 10 -6 K -1 When the thermal expansion exceeds a critical value, the separation layer or a carrier substrate disposed on the other side of the separation layer can be separated or peeled off from at least one other layer or substrate.

[0085] A very small selected pulse width allows a larger amount of heat to be introduced into the separation layer per unit time than is discharged to the surroundings. This leads to sublimation and partially to the formation of plasma. If the pulse width is selected too large, the inorganic separation layer will melt. The more rapid discharge of heat to the surroundings leads to a very rapid solidification of the melt again and thus to a new weld between the separation layer and the surroundings.

[0086] The melting of an inorganic separating layer is also conceivable. As already mentioned, during melting, it must be ensured that the new solidification of the melt does not weld the separating layer again to its surroundings.

[0087] In a particularly preferred procedure, the laser surfaces (English: laser spots) do not overlap in the separation layer. In this case, the step width between two laser surfaces formed must be larger than the laser surface of the laser beam. Each laser area or active area in the separation layer is irradiated with a corresponding laser beam of the laser unit. The following parameter sets are given by way of example: For a preferably circular laser surface with a laser surface diameter of 10 μm, the step width is 10 μm to 30 μm, preferably 10 μm to 25 μm, even more preferably 10 μm to 20 μm, more preferably 10 μm to 15 μm, most preferably 10 μm to 12 μm. The step width is larger than the laser surface diameter, but is preferably selected to be sufficiently large to provide an efficient weakening of the separation layer or adhesion properties of the separation layer. For example, in the case of a laser surface diameter of 10 μm, it can be ensured that the weakening or destruction of the separation layer takes place with a step width of 30 μm. In particular, it is not necessary in this case to reduce the step width, for example, to 15 μm or even to 12 μm.

[0088] In case of overlapping laser faces, the sublimated inorganic material of the separation layer of one laser face may condense or resublime on the adjacent laser face, resulting in a new weld. In the prior art, the polymer absorbs the sublimated separation layer material. Therefore, an important aspect of all the embodiments of the method and the device for separating the carrier substrate is that the step width between the two laser faces can be precisely selected to prevent a new weld when the laser faces are predefined. Furthermore, it is noted that lasers with correspondingly short pulse widths do not work in systems with organic layers.

[0089] The following layer or substrate systems are defined for separation during bonding or debonding:

[0090] In a first embodiment, the layer system consists solely of one inorganic separating layer, which is preferably applied to a substrate, in particular a carrier substrate, and which simultaneously acts as a bonding layer.

[0091] In a second embodiment, the layer system consists of at least one separating layer and a bonding layer. The separating layer is preferably applied on a substrate, in particular a carrier substrate. The bonding layer is applied on the separating layer. The task of the bonding layer is to establish a bond with another substrate (at least one further layer), in particular a product substrate, whereas the separating layer has the task of being weakened or destroyed by the laser unit.

[0092] The following layer or substrate systems are defined for the layer transfer, so that at least one further layer or substrate stack can advantageously be transferred, for which a method of separating the carrier substrate is used.

[0093] In a third embodiment, the layer system consists of at least a separation layer and a transfer layer. The separation layer is preferably applied on a substrate, in particular a carrier substrate. The transfer layer is applied on the separation layer.

[0094] In a fourth embodiment, the layer system consists of at least a separation layer, a growth layer and a transfer layer. The separation layer is preferably deposited on a substrate, in particular on the separation layer. The growth layer is deposited on the separation layer and is used to form, in particular to grow, the transfer layer thereon.

[0095] In a fifth embodiment, the layer system consists of at least a separation layer, a growth layer, a mask and a transfer layer. The separation layer is preferably applied on a substrate, in particular a carrier substrate. The growth layer is applied on the separation layer. On the growth layer, a mask is formed, in particular a hard material mask, produced by a combination of sol-gel deposition, imprinting and curing processes. The deposition method forms an overgrowth layer, which grows starting from the growth layer through the openings in the mask. This growth layer represents the transfer layer.

[0096] The layer systems or substrate systems described above can be used here to carry out the method for separation.

[0097] In the first method, a separation layer is used for debonding two substrates. For clarity and ease of illustration, the method is described for two substrates, a carrier substrate and a product substrate. However, the method can be used to form a substrate stack comprising multiple substrates.

[0098] In particular, it is conceivable that the inorganic layer, in particular the separation layer, changes between the two substrates in each case. In the case of a plurality of substrates, there is preferably a carrier substrate and a plurality of product substrates arranged on the carrier substrate. It is also conceivable that the substrate stack consists only of product substrates. In this case, however, it is desirable that at least one of the product substrates is of such a thickness that the substrate stack is sufficiently mechanically stabilized or that the substrate stack as a whole is of such a thickness that there is a mechanical stabilization.

[0099] In a first method step, a release layer is applied onto a carrier substrate, a bonding layer is applied onto the release layer, and a product substrate is bonded to the bonding layer.

[0100] In a second method step, the product substrate is treated.

[0101] In a third method step, the product substrate is bonded with its treated product substrate surface to another substrate, in particular a transfer substrate.

[0102] In a fourth method step, the separation layer is irradiated with a laser beam of a laser through the carrier substrate.

[0103] In a fifth method step the carrier substrate is removed or peeled away.

[0104] A first particular method uses a layer system consisting of a separating layer and a bonding layer.

[0105] A separation layer is formed on the carrier substrate. A bonding layer is formed on the separation layer. A product substrate, in particular also provided with a bonding layer, is bonded to the bonding layer of the carrier substrate. This bonding is preferably a fusion bonding. The product substrate in particular already comprises functional units. In a further process step, the second product substrate surface that is not bonded is treated. In particular, a backside thinning to less than 100 μm, preferably less than 50 μm, even more preferably less than 25 μm, more preferably less than 10 μm, most preferably less than 5 μm is performed. On the backside-thinned product substrate, further method steps can be performed, in particular also at high temperatures. Preferably, an oxidation of the second product substrate surface is performed and through-silicon vias (TSVs) are formed, whereby the second product substrate surface becomes a hybrid bonding surface. A further fusion bonding of the second product substrate to the second product substrate surface of the first product substrate is conceivable. The bonding is preferably hybrid bonding, i.e. the electrical contacts of the first product substrate are directly connected to the electrical contacts of the second product substrate, while the dielectric environments of the electrical contacts are connected to one another by fusion bonding. The product substrate surface of the second product substrate preferably also has a bonding layer in this case. If the substrate stack consisting of the first product substrate and the second product substrate is mechanically stable enough, a method for weakening the separation layer can be used for the separation layer. A laser beam is focused on the separation layer, preferably through a carrier substrate that is transparent or transparent to the specific wavelength of the laser. As a result, the separation layer loses its adhesion strength or is at least partially, preferably completely, removed. Afterwards, both product substrates that were bonded to one another can be removed from the carrier substrate.

[0106] In this case, exclusively inorganic layers are used, ie the separating layer as well as all bonding layers are inorganic.

[0107] In the second method, a separation layer is used to transfer the transfer layer, a process called layer transfer.

[0108] In a first method step, a carrier substrate is provided. At least one separation layer is applied onto the carrier substrate. At least one transfer layer is present on the separation layer. It is also conceivable and preferred to first apply a growth layer onto the separation layer and then apply a transfer layer onto the growth layer. It is also conceivable that the transfer layer is an overgrowth layer, which has to be grown through a mask. The generation of such an overgrowth layer is described in detail in WO2016184523. It is also conceivable that a diffusion layer has to be deposited between the separation layer and the transfer layer, so that the separation layer and the transfer layer do not mix with each other in further method steps.

[0109] In a second method step, the free transfer layer surface of the transfer layer is aligned with respect to a product substrate. The product substrate may already have functional units and / or further layers. It is also conceivable that the substrate is a transfer substrate, which only temporarily accommodates the transfer layer and is transferred to the product substrate in a further method step. In this case, a corresponding inorganic separation layer can also be formed on the transfer substrate.

[0110] In a third method step, the transfer layer is bonded to the product substrate.

[0111] In a fourth method step, the separation layer is irradiated with a laser beam, whereby the separation layer loses its adhesive strength and / or is at least partially destroyed.

[0112] In a fifth method step, the carrier substrate is removed, leaving the transfer layer on the product substrate, in particular the growth layer still remaining on the transfer layer.

[0113] In a sixth method step, any growth layer still present is removed from the transfer layer.

[0114] The difference between the exemplary methods for separation is, inter alia, that on the one hand, two substrates are separated from each other, and on the other hand, a layer is transferred. For all the above-mentioned methods, an inorganic separation layer is required.

[0115] Then, an exemplary list of preferred materials and process parameters is disclosed, which allows the separation layer to be particularly optimally used for separation by laser irradiation.

[0116] [Table 1]

[0117] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and the drawings. [Brief description of the drawings]

[0118] [Figure 1a] FIG. 2 is a side view that illustrates a schematic representation of a substrate with a separation layer that can also act as a bonding layer. [Figure 1b] FIG. 2 shows a schematic side view of a substrate with a separation layer and a separate bonding layer. [Figure 2a] FIG. 2 is a side view that illustrates a schematic diagram of a substrate having a separation layer and a transfer layer. [Figure 2b] FIG. 2 is a schematic side view of a substrate comprising a separation layer, a growth layer, and a transfer layer. [Figure 2c] FIG. 2 shows a schematic side view of a substrate comprising a separation layer, a growth layer, a mask and a transfer layer. [Figure 3a] FIG. 2 shows a schematic diagram of a first method step of a first exemplary method. [Figure 3b] FIG. 3 shows a schematic diagram of a second method step of the first method. [Figure 3c] FIG. 4 shows a schematic diagram of a third method step of the first method. [Figure 3d] FIG. 4 shows a schematic diagram of a fourth method step of the first method. [Figure 3e]FIG. 4 shows a schematic diagram of a fifth method step of the first method. [Figure 4a] FIG. 2 shows a schematic diagram of a first method step of an exemplary first particular method. [Figure 4b] FIG. 2 shows a schematic diagram of a second method step of the first special method. [Figure 4c] FIG. 2 shows a schematic diagram of a third method step of the first special method. [Figure 4d] FIG. 2 shows a schematic diagram of a fourth method step of the first special method. [Figure 4e] FIG. 2 shows a schematic diagram of a fifth method step of the first special method. [Figure 4f] FIG. 2 shows a schematic diagram of the sixth method step of the first special method. [Figure 4g] FIG. 2 shows a schematic diagram of the seventh method step of the first special method. [Figure 4h] FIG. 13 is a schematic diagram illustrating the eighth method step of the first special method. [Figure 4i] FIG. 13 is a schematic diagram illustrating the ninth method step of the first special method. [Figure 5a] FIG. 2 shows a schematic diagram of a first method step of the second exemplary method. [Figure 5b] FIG. 4 shows a schematic diagram of a second method step of the second method. [Figure 5c] FIG. 4 shows a schematic diagram of a third method step of the second method. [Figure 5d] FIG. 4 shows a schematic diagram of a fourth method step of the second method. [Figure 5e] FIG. 10 shows a schematic diagram of a fifth method step of the second method. [Figure 5f] FIG. 10 shows a schematic diagram of a sixth method step of the second method.

[0119] In the figures, identical components or components having the same function are provided with the same reference symbols.

[0120] 1a-b show two basic substrate or layer systems on a carrier substrate 1, the task of which is to provide a separating layer 2 and a bonding layer 14. In this case, all layers are inorganic.

[0121] Fig. 1a shows a side view of a carrier substrate 1 on which a separation layer 2 has been applied. The separation layer 2 is inorganic. It is deposited directly on the substrate 1 by methods known from the prior art. This combination of carrier substrate 1 and separation layer 2 can be used to bond a second substrate. The separation layer 2 in this case not only acts as a separation layer but also at the same time as a bonding layer 14. In this case, the carrier substrate 1 is the carrier substrate that has the task of mechanically stabilizing the second substrate.

[0122] Figure 1b shows a side view of the carrier substrate 1 on which a separating layer 2 has been applied. The separating layer 2 is inorganic. On the separating layer 2 an adhesive layer 14 is provided, to which another substrate, which preferably also has an adhesive layer 14, can be bonded. The adhesive layer 14 is inorganic and is preferably a dielectric, in particular an oxide layer, most preferably a silicon oxide layer.

[0123] 2a-c show four basic substrate or layer systems, which in addition to the inorganic separation layer have at least one further layer. Furthermore, the carrier substrate provides a separation layer 2 and a transfer layer 3. All layers of the substrate system are inorganic. These layer systems serve to transfer the transfer layer 3 onto another substrate (not shown), in particular the product substrate 6, but not to bond the carrier substrate 1 to a substrate (not shown), in particular the product substrate 6. The transfer layer 3 is designed as wide as possible. The transfer layer 3 can therefore be understood both as an individual layer and as a layer system. The transfer layer 3 can be, for example, an embossed layer with a structure. The transfer layer 3 can be, for example, a layer with a plurality of lenses, microchips, MEMS, LEDs, etc. The thickness of the transfer layer 3 can be from a few angstroms to a few millimeters.

[0124] 2a shows a side view of a carrier substrate 1 on which a release layer 2 is deposited. The release layer 2 is inorganic. On top of the release layer 2 there is a transfer layer 3, which is preferably transferred onto another substrate (not shown), in particular onto a product substrate 6.

[0125] FIG. 2b shows a side view of a carrier substrate 1 on which a separation layer 2 has been applied. The separation layer 2 is inorganic. On the separation layer 2 there is a growth layer 4. On the growth layer 4 a transfer layer 3 is formed. The transfer layer 3 can be transferred in a certain way to another substrate (not shown), in particular to a product substrate 6. FIG. 2b is a special case of FIG. 2a. As a rule, the separation layer 2 does not provide the necessary prerequisites for forming the desired transfer layer 3, first a growth layer 4 must be formed, on which the transfer layer 3 can be grown.

[0126] FIG. 2c shows a side view of the carrier substrate 1 on which the separation layer 2 is applied. The separation layer 2 is inorganic. On the separation layer 2 there is a growth layer 4. On the growth layer 4 a mask 5 is applied. The mask 5 is preferably pressed directly from a liquid, preferably from a sol-gel, by a pressing process and hardened. However, the mask 5 can be formed by any other method. After that, the material for the transfer layer 3 is deposited. The material of the transfer layer 3 is first deposited in the openings of the mask 5 and grows beyond the openings to form the full-surface transfer layer 3. Such a transfer layer 3 is called an overgrowth layer. The transfer layer 3 can be transferred to another substrate (not shown), in particular to a product substrate 6, in a method for separation. FIG. 2c is a special case of FIG. 2b. In addition to the growth layer 4, a further mask 5 is formed. The advantage of the production of such a transfer layer 3 is that this transfer layer 3 is substantially defect-free.

[0127] An adhesive layer 14 may be further applied onto the above-mentioned transfer layer 3 in order to increase the adhesive strength to a substrate (not shown) to which the transfer layer 3 is to be transferred, in particular to a product substrate 6. Since the illustration of such an adhesive layer 14 has already been shown in Figures 1a-1b, it is omitted in Figures 2a-2c for clarity.

[0128] Figure 3a shows a side view of a first method step of a first possible method. A carrier substrate 1 (see Figure 1b) with a separating layer 2 and a bonding layer 14 is bonded and bonded to a product substrate 6. The product substrate 6 is bonded to the bonding layer 14 via the first product substrate surface. In another way, the carrier substrate 1 has the task of mechanically stabilizing the product substrate 6.

[0129] Fig. 3b shows a side view of a second method step of a first possible method. A second product substrate surface of the product substrate 6 is treated. By way of example, a backside thinning of the product substrate 6 is shown. However, in this method step a myriad of other processes can be carried out. In particular, LEDs, MEMS, microcontrollers, etc. can be produced. In order to keep the figure as simple as possible, the depiction of these processes is omitted.

[0130] 3c shows a side view of the third method step of the first possible method. The product substrate 6 is aligned and bonded via its treated second product substrate surface to a transfer substrate 7. In this case, the transfer substrate 7 is a film 9 stretched on a frame 8. However, the transfer substrate 7 can also be another substrate, in particular another carrier substrate 1 or another product substrate 6.

[0131] Fig. 3d shows a side view of the fourth method step of the first possible method. In this case, a laser 10 is used to focus a laser beam 11 onto the separation layer 2. By using a laser 10 with corresponding laser parameters, in particular with a very short pulse width in the picosecond range, the separation layer 2 is decomposed or the adhesion strength to the carrier substrate 1 is reduced at least to such an extent that the carrier substrate 1 can be detached.

[0132] Figure 3e shows a side view of the fifth method step of the first possible method. The product substrate 6 lies on the transfer substrate 7 after removal of the carrier substrate 1 (not shown, see Figure 3d). The separation layer 2 has been removed or has already been removed automatically during the method step according to Figure 3d.

[0133] In another drawing, a second method is shown, which is of great importance in the semiconductor industry. The second method is generalized and abstracted as much as possible, but is characterized by the use of an inorganic separation layer 2 and an intrinsic bonding layer 14.

[0134] Figure 4a shows a side view of the first method step of the first special method: An isolation layer 2 is deposited on a carrier substrate 1. An adhesion layer 14 is formed on the isolation layer 2 (see Figure 1b). The adhesion layer 14 is preferably a dielectric layer, more preferably an oxide, most preferably a silicon oxide.

[0135] Fig. 4b shows a side view of the second method step of the first special method. The product substrate 6, which already comprises functional units 12 and whose product substrate surface 6o is preferably coated with an adhesive layer 14, is aligned relative to the carrier substrate 1. The functional units 12 preferably have electrical contacts 15. If the product substrate surface 6o of the product substrate 6 adheres sufficiently well to the adhesive layer 14 of the carrier substrate 1, the use of the adhesive layer 14 on the product substrate 6 can be omitted. Preferably, however, the adhesive layer 14 is present on the product substrate 6, but more preferably the material of both adhesive layers 14 on the carrier substrate 1 and on the product substrate 6 is the same. Most preferably, the adhesive layer is an oxide.

[0136] Fig. 4c shows a side view of the third method step of the first special method. The product substrate 6 is bonded to the carrier substrate 1 via the bonding layer 14. If the bonding layer is an oxide, this is fusion bonding. Before the possible heat treatment, it is called pre-bonding. After the heat treatment, after which covalent bonds are formed between the contacting bonding layer surfaces of the bonding layer 14, it is called fusion bonding. The method step of the heat treatment is not shown. In this case, it is important that the product substrate 6 adheres sufficiently well to the carrier substrate 1 in order to be able to be processed further. If the adhesion strength is high enough without heat treatment, it is even conceivable not to carry out the heat treatment.

[0137] 4d shows a side view of the fourth method step of the first special method, in which a backside thinning of the product substrate 6 is performed. Backside thinning is very often desired in order to significantly minimize the thickness of the final product.

[0138] 4e shows a side view of the fifth method step of the first special method. The back thinned product substrate surface of the product substrate 6 is coated with a bonding layer 14, in particular with a dielectric layer, preferably with an oxide, most preferably with a silicon oxide. By the bonding layer 14 and the product substrate 6 through silicon vias (TSVs) 13 are formed, which make accessible and usable the electrical contacts 15 of the functional units 12 provided on the surface of the bonding layer 14.

[0139] FIG. 4f shows a side view of the sixth method step of the first special method. The second product substrate 6', which also comprises the functional units 12, the TSVs 13 and the bonding layer 14, is aligned relative to the first product substrate 6 or the carrier substrate 1. The second product substrate 6' is probably also fixed on the carrier substrate 1', or even preferably fixed by means of the method. However, in order not to clutter the drawing, the illustration of the carrier substrate 1' with the corresponding separating layer 2 and bonding layer 14 or any other layer system is omitted. This alignment is performed via alignment marks (not shown) and an alignment system with highly accurate optics (not shown) specially provided for the alignment marks.

[0140] 4g shows a side view of the seventh method step of the first special method. Both product substrates 6, 6' are bonded to one another via their bonding layers 14. In this case, the TSVs 13 are precisely bonded to one another so that an electrical connection between the functional units 12 of the product substrates 6, 6' is possible.

[0141] Fig. 4h shows a side view of the seventh method step of the first special method. In this case, a laser 10 is used to focus a laser beam 11 onto the separation layer 2. By using a laser 10 with corresponding laser parameters, in particular with a very short pulse width in the picosecond range, the separation layer 2 is decomposed or the adhesion strength to the carrier substrate 1 is reduced at least to such an extent that the carrier substrate 1 can be detached.

[0142] 4i shows a side view of the seventh method step of the first special method, where a substrate stack 16 consisting of two product substrates 6, 6' permanently bonded together is visible.

[0143] This substrate stack can be correspondingly post-processed. It is to be noted that in Fig. 4i the representation of the carrier substrate 1' has been omitted for the sake of clarity. On such a carrier substrate 1' the substrate stack 16 can still be transported and / or further processed without any problems.

[0144] In figures 4a to 4i a separation layer 2 has been used and described which has an adhesive layer 14 thereon. According to the general embodiment shown in figure 1a, the separation layer 2 and the adhesive layer 14 may be identical.

[0145] 5a shows a side view of a first method step of the second method, in which a carrier substrate 1 is provided with at least one separation layer 2 and a transfer layer 3. Preferably, a further growth layer 4 is present on the separation layer 2 in order to be able to produce, in particular grow, the transfer layer 3.

[0146] 5b shows a side view of a second method step of a second method, in which a product substrate 6, preferably with functional units 13, is aligned relative to a carrier substrate, again by means of alignment marks (not shown) and a special alignment system (not shown).

[0147] 5c shows a side view of a third method step of the second method, in which the product substrate 6 is contact-connected to the transfer layer 3. In this case, it is desired that the transfer layer 3 is contact-connected directly to the functional units 12. It is conceivable, for example, for the transfer layer 3 to be structuring in a later method step. The transfer layer 3 can be, for example, a graphene layer grown on a growth layer 4 made of copper. An RDL layer (English: redistribution layer) can be formed from the transfer layer 3 on the product substrate surface of the product substrate 6.

[0148] FIG. 5 d shows a side view of a fourth method step of the second method, in which a laser beam 11 of a laser 10 is focused onto the separation layer 2 .

[0149] FIG. 5e shows a side view of a fifth method step of the second method, in which the carrier substrate 1 (not shown, see FIG. 5d) is removed.

[0150] FIG. 5f shows a side view of a sixth method step of the second method, in which the growth layer 4 is further removed. [Explanation of symbols]

[0151] 1 Carrier Board 2 separation layer 3 Transfer layer 4 growth layer 5. Mask 6,6' Product Board 7 Transfer substrate 8 Frames 9. Film 10 Laser unit, laser 11 Laser Beam 12 Functional Units 13 TSV 14 Bonding layer 15 Electrical Contacts 16 Board Stack

Claims

1. A method for separating a carrier substrate (1) from a product substrate (6), comprising at least i) providing a carrier substrate (1) and a product substrate (6) with a separation layer (2) arranged between the carrier substrate (1) and the product substrate (6), the separation layer fixing the product substrate in position on the carrier substrate; ii) irradiating the separation layer (2) with a laser beam (11) from a laser unit (10); iii) separating the carrier substrate (1) from the product substrate (6); It has A method characterized in that said separating layer (2) is inorganic.

2. 2. The method of claim 1, wherein at least one further layer (3, 4, 5, 6', 7, 14) is disposed between the separating layer and the product substrate (6), and wherein the at least one further layer (3, 4, 5, 6', 7, 14) is inorganic.

3. 3. The method according to claim 1, wherein only inorganic layers are arranged between the product substrate and the carrier substrate.

4. 4. The method according to claim 1, wherein during irradiation in step ii), the laser beam (11) emitted from the laser unit (10) first penetrates the carrier substrate (1) and then strikes the separation layer (2).

5. 5. The method according to claim 1, wherein the at least one further layer (3, 4, 5, 6', 7, 14) is a silicon oxide layer acting as a bonding layer (14).

6. 6. The method according to claim 1, wherein the at least one further layer (3, 4, 5, 6', 7, 14) is formed from a first oxide layer and a second oxide layer, in particular by fusion bonding.

7. 7. The method according to claim 1, wherein the separating layer (2) consists of a metal or a nitride, preferably TiN.

8. 8. The method according to at least one of claims 1 to 7, wherein the laser beam (11) has a wavelength of 0.1 μm to 500 μm, preferably 0.2 μm to 100 μm, even more preferably 0.3 μm to 50 μm, even more preferably 0.5 μm to 10 μm, and most preferably 1 μm to 2.5 μm.

9. 9. The method according to at least one of claims 1 to 8, wherein the pulse energy of the laser beam (11) is between 0.01 μJ and 128 μJ, preferably between 0.125 μJ and 64 μJ, even more preferably between 0.25 μJ and 32 μJ, even more preferably between 0.5 μJ and 16 μJ, and most preferably between 1 μJ and 8 μJ.

10. Laser area: 2000 μm ２ less than 500 μm, preferably ２ less than 80 μm, more preferably ２ less than 20 μm, more preferably ２ less than 1 μm, most preferably ２ 10. The method according to claim 1, wherein the total mass of the polymer is less than 1000 mol / L.

11. 11. The method according to claim 1, wherein the areas of action of the laser beams (11) on the separating layer (2) are spaced apart by at least 0.1 μm, preferably at least 1 μm, even more preferably at least 5 μm, more preferably at least 10 μm, and most preferably at least 50 μm, so that the areas of action of the laser beams (11) do not overlap.

12. 12. The method according to at least one of claims 1 to 11, wherein the pulse width of the laser beam (11) is between 10,000 ps and 1 ps, preferably between 1,000 ps and 1 ps, even more preferably between 500 ps and 1 ps, even more preferably between 100 ps and 1 ps, and most preferably between 50 ps and 1 ps.

13. A substrate system, in particular for producing semiconductor components, comprising at least A) a carrier substrate (1); B) a separation layer (2) disposed on the carrier substrate (1); C) a product substrate (6) disposed on the separation layer; It has a substrate system, wherein the carrier substrate (1) is separable from the product substrate (6) by irradiation of the separation layer (2) by a laser unit (10); A substrate system, characterized in that the separation layer (2) is inorganic, and the separation layer (2) fixes the product substrate (6) in position on the carrier substrate.

14. 14. The substrate system according to claim 13, wherein at least one further layer (3, 4, 5, 6', 7, 14) is arranged between the separation layer (2) and the product substrate (6), and the product substrate (6) is fixed in position on the carrier substrate (1) by the at least one further layer (3, 4, 5, 6', 7, 14), and the at least one further layer is inorganic.

15. 15. The substrate system of claim 14, wherein the at least one other layer is a bonding layer (14), which is formed from at least a first oxide layer and a second oxide layer, in particular by fusion bonding.

16. 16. The substrate system according to at least one of claims 13 to 15, wherein only inorganic layers are arranged between the carrier substrate (1) and the product substrate (6).

17. The substrate system according to at least one of claims 13 to 16, wherein the separation layer (2) has a separation layer thickness of 10 nm to 500 nm.

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