Process and substrate system for separating carrier substrates

Abstract

The invention relates to a process and a substrate system for separating a carrier substrate from a substrate, in particular a product substrate, by irradiating a separating layer.

Description

[0001] Description

[0002] Method and substrate system for separating carrier substrates

[0003] The present invention relates to a method, a device, and a substrate system for separating carrier substrates from further layers. The carrier substrate can be separated using various substrate processing methods, for example, during debonding or substrate transfer.

[0004] In the semiconductor industry, it is becoming increasingly important to develop processes and devices that can, on the one hand, create strong adhesion between surfaces and, on the other hand, prevent adhesion when necessary. Such processes and devices for processing substrates are primarily used for two different techniques: layer transfer and substrate bonding or debonding.

[0005] During layer transfer, especially inorganic, usually very thin, mechanically unstable layers are transferred between self-supporting substrates. The inorganic layers are generated, for example, on special growth substrates, but must then be transferred to another substrate, especially a product substrate, in order to fulfill their functional properties. In very rare cases, the growth substrate and the product substrate are identical.

[0006] In the current state of the art, so-called release layers or separating layers are used to achieve a targeted, localized separation of the wear layer from a carrier substrate. To date, organic polymer layers have been used as bonding layers, which require a complex additional cleaning step during the transfer of the wear layer and increase contamination.

[0007] When bonding and debonding substrates, two substrates are first joined together so that one of the two substrates, which usually does not have sufficient internal stability for the process due to its lower thickness or strength, can be processed with the support of the second substrate. The processed substrate is called the product substrate, and the supporting substrate is called the carrier substrate. Polymers are predominantly used to create a so-called temporary bond, i.e. a bond that can be removed non-destructively. For this purpose, at least one polymer is applied to a substrate using a process, in particular a spin-coating process. The carrier substrate is predominantly coated with the polymer (release layer) and the carrier substrate is bonded to the product substrate. After the product substrate has been bonded to the carrier substrate, the product substrate is further processed in order to be separated from the carrier substrate again in a later process step.There are different methods available in the state of the art for separating the carrier substrate.

[0008] In the early years, the carrier substrate was usually coated over its entire surface with the polymer. This resulted in very good adhesion between the carrier and the product substrate. If the product substrate has raised areas, such as solder bumps, dies, or chips, these can be embedded in the polymer, provided the polymer layer acting as a separation layer is sufficiently thick. The disadvantage of this method becomes apparent when separating the carrier substrate from the product substrate. Separation requires the polymer layer to be applied over its entire surface, making complete separation more complex and involving multiple processing steps. The adhesive force of the adhesive layer can be reduced to such an extent that mechanical separation is possible by applying a chemical to the adhesive layer from the side of or through the carrier substrate. The chemical is preferably exposed to the adhesive layer at elevated temperatures.

[0009] When separating a full-surface polymer layer, removing the adhesive materials also requires more energy (e.g., heat, ultrasound) or solvent, and thus also higher costs. In this process, the separation itself is preferably controlled by detachment forces perpendicular to the substrate surface.

[0010] An alternative development is so-called "slide-off debonding." This process uses a device that fixes the product substrate and the carrier substrate over their entire surface, each with a substrate holder. The two substrate holders are then moved parallel to each other, so that the substrates are sheared apart by forces along the bonding surface. This requires heating the polymer layer between them. This softens the polymer layer and causes it to lose its adhesive strength. The advantage of this method is that solvents and ultrasound can be completely dispensed with. The disadvantage is that the debonding still has to be carried out at an elevated temperature.

[0011] Alternative debonding methods avoid the use of elevated temperatures and rely exclusively on solvents that attack the polymer from the periphery of the two substrates. The action of the solvent can be accelerated using ultrasound. The dissolved polymer is preferably transported away from the substrate stack by circulating the solvent and is preferably continuously removed from the solvent bath. It is also possible to spray the solvent onto the polymer sideways and remove it using a solvent jet.

[0012] A further development of the solvent process is the so-called ZoneBond™ method, which is described in the document W02009094558A2. This is a process in which a carrier substrate must be specially prepared. The carrier substrate consists of two different zones. The central zone, which takes up the largest area, is coated with an anti-sticking layer and has low adhesion to any type of polymer. The second zone surrounds the first zone in a circle, usually as a closed ring, and extends to the edge of the carrier substrate. The thickness of the ring is only a few millimeters. This very small area is sufficient to fix the polymer and thus the product substrate bonded to the carrier substrate over the entire surface. The interior is held in place during the processing steps by air pressure and the sealing of the sides.The advantage is that for debonding only the polymer from the second, more easily accessible zone needs to be removed to enable debonding of the carrier substrate from the product substrate.

[0013] A further development involved the use of photosensitive release layers. These were usually applied to a carrier substrate, particularly a transparent one. The carrier substrate was then coated with a polymer layer and bonded to a product substrate. After the product substrate had been fully processed, the release layer could be released from the product substrate by irradiating the carrier substrate through the release layer. Such processes are described, for example, in the publications US20150035554A1, US20160133486, and US20160133495A1. A specific embodiment of this process, in which the release layer was applied to the product substrate rather than the carrier substrate, can be found in the publication WO2017076682A1.

[0014] The methods mentioned can be combined with one another. For example, the orientation of the product substrate can also be changed. Since the carrier substrates are changed in this method, it is also referred to as a carrier flip. For example, WO2011120537A1 describes a method in which a product substrate is fixed to a first carrier using a polymer layer and then processed. After processing, in particular re-thinning, the product substrate is very thin and is bonded to a second carrier substrate for further use of the other substrate side. The product substrate is transferred via two polymer layers. The first carrier substrate must be separated from the product substrate after the product substrate has been fixed to the second carrier substrate.

[0015] All of the above-mentioned methods are generally based on influencing some part, especially a layer, in such a way that adhesion to other parts is reduced, or even completely eliminated. In other words, the adhesive properties of the release layer are reduced.

[0016] The devices and methods described in the prior art thus describe a separation process that provides organic layers, in particular polymer layers, as a separation layer or combines organic bonding layers with inorganic separation layers. The use of polymers as bonding layers and / or separation layers that temporarily bond two substrates has several disadvantages. The polymers are long-chain molecules whose main component is carbon. Organic materials are often disadvantageous and undesirable in the semiconductor industry because they can contaminate a cleanroom environment, especially the equipment in which the substrates are processed.Furthermore, these polymers have the disadvantage that they only maintain their adhesive properties down to relatively low temperatures, which is an advantage for debonding, but a disadvantage if the product substrate on the carrier substrate needs to be processed at high temperatures. In addition to the low temperature resistance of organic layers, organic release layers often have to be applied relatively thickly to provide appropriate adhesive properties.

[0017] In addition to the problems associated with debonding, the current state of the art also presents the problem of transferring layers produced on substrates to product substrates, as a release layer is also used for this purpose to separate the resulting substrate stack from the carrier substrate. The different processes are therefore characterized by the fact that, on the one hand, high holding forces are required during processing, regardless of the process temperature, and, on the other hand, the substrates must be separated from each other after processing with the lowest possible forces.

[0018] 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 eliminate, in particular completely eliminate, the disadvantages listed in the prior art. It is a particular object of the invention to provide an improved method and improved substrate system for separating substrates or for separating layers on a substrate. It is a further object of the invention to provide an alternative method and an alternative substrate system with the aid of which a substrate can be processed simply and cleanly, in particular debonded or transferred. It is a further object of the present invention to provide a method and a substrate system which operate with low contamination or which enable such operation.Furthermore, it is an object of the present invention to provide a substrate system from which, in particular, a carrier substrate can be separated or detached particularly easily.

[0019] The present object is achieved by the features of the independent claims. Advantageous developments of the invention are specified in the dependent claims. The scope of the invention also includes all combinations of at least two features specified in the description, the claims, and / or the drawings. For specified value ranges, values ​​within the specified limits are also considered to be disclosed as limit values ​​and can be claimed in any combination.Accordingly, the invention relates to a method for separating a carrier substrate from a product substrate, comprising at least the following steps: i) providing the carrier substrate and the product substrate with a separating layer arranged therebetween, wherein the separating layer fixes the product substrate to the carrier substrate, ii) irradiating the separating layer with laser beams from a laser unit, and iii) separating the carrier substrate from the product substrate, characterized in that the separating layer is inorganic.

[0020] The separating layer simultaneously functions as a bonding layer or adhesive layer, particularly for temporarily attaching the carrier substrate to the product substrate. The product substrate can be a substrate stack, a component, or a single functional layer. In this respect, the separating method is also generally intended for separating any other substrate from the carrier substrate. Particularly preferably, the separating layer is arranged directly on the carrier substrate. In this way, an additional bonding layer can advantageously be dispensed with.

[0021] In addition, in addition to the inorganic separation layer, no further layers, especially no organic layers, are required for the separation process. This advantageously reduces the degree of contamination.

[0022] In a further embodiment of the method, it is provided that at least one further layer is arranged between the separating layer and the product substrate, and wherein the at least one further layer is inorganic.

[0023] In other words, the method advantageously allows a substrate system comprising at least the carrier substrate, the separating layer, and one additional layer to be processed by targeted laser treatment such that the carrier substrate can be easily separated or detached from the at least one additional layer with minimal contamination. In contrast to the prior art, a separating layer made of carbon-free material is exposed to laser beams using a laser, so that the adhesive properties of this inorganic separating layer are reduced, while the additional layer is also inorganic. By releasing the carrier substrate by acting on the inorganic separating layer, a completely inorganic layer structure of the substrate system is possible.Thus, in various processes for processing substrates, in particular in debonding and transferring substrates, the use of organic separating layers or bonding layers can be advantageously dispensed with.

[0024] The higher temperature resistance of inorganic materials enables more flexible process design. Furthermore, inorganic separation layers and bonding layers typically exhibit good thermal conductivity, allowing for better heat dissipation via the carrier substrate.

[0025] In addition, organic release layers and organic bonding layers based on polymers can cause adverse contamination in corresponding systems and negatively impact quality. Using inorganic materials for the release layer and bonding layer can thus reduce contamination in the systems.

[0026] The high adhesive properties of the inorganic separating layers and / or bonding layers also enable a thinner separating layer and thus a thinner overall layer structure in the substrate system to be processed. This can result in improved flatness of the substrate system and save material that needs to be processed and thus contaminates it. A further advantage of the process for separating carrier substrates is the lower energy input into the substrate system to be processed and a correspondingly lower heat load, which makes it particularly suitable for processing temperature-sensitive substrate systems.

[0027] The separating layer is formed from a carbon-free material and is deposited, in particular, beforehand onto the carrier substrate. In this respect, the separating layer can also simultaneously serve as a bonding layer (temporary bond) for connecting to the product substrate via the at least one additional layer.

[0028] A carrier substrate is understood to mean any substrate suitable for applying the inorganic separating layer. The carrier substrate is preferably an inorganic substrate, particularly preferably a silicon wafer. Silicon wafers are particularly preferred.

[0029] The laser unit acts on the separating layer in a targeted manner and with coordinated parameters in different, preferably regularly exposed areas. The inorganic separating layer, which is preferably impermeable to the laser radiation from the laser unit, absorbs the laser radiation, thus locally reducing the adhesive properties and / or stability of the separating layer. In particular, the high local energy concentration causes lateral cracks in the separating layer, so that the carrier substrate can be easily separated from the at least one other layer or the product substrate. The inorganic separating layer can then be used to specifically separate the carrier substrate from the at least one other layer in the separating process.

[0030] A possible, though not preferred, approach is to use a large-area laser irradiation, particularly a continuous one. In this case, the laser beam does not move relative to the substrate, but is expanded so that it hits the entire surface of the substrate. In particular, in such a specific embodiment, the exposure time must be much longer. In a preferred embodiment of the method, only inorganic layers are arranged between the product substrate and the carrier substrate. In this way, the method can be carried out with particularly low contamination.

[0031] In a preferred embodiment of the method, during irradiation in step ii), laser beams emitted by the laser unit first penetrate the carrier substrate and then strike the separating layer. In other words, the laser beams first pass through the carrier substrate and are subsequently absorbed by the separating layer. The carrier substrate is thus at least partially transparent to the laser radiation. The laser unit can thus advantageously be arranged on the rear side of the carrier, and separation can be carried out flexibly from the rear side without placing special demands on the product substrate. In this context, it should be noted that the at least one further layer, if present, also absorbs the laser radiation to such an extent that the product substrate is advantageously protected.

[0032] In a preferred embodiment of the method, the at least one additional layer is a silicon oxide layer that functions as a bonding layer. This inorganic bonding layer allows for a low-contamination separation process.

[0033] In a preferred embodiment of the method, the at least one further layer is produced 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. In a preferred embodiment of the method, the separating layer is made of a metal or nitride, preferably TiN. An inorganic separating layer made of metal or nitride is particularly suitable, as it also enables stable bonding. A tin-based separating layer is particularly preferred.

[0034] In a preferred embodiment of the method, the laser beams have a wavelength between 0.1 μm and 500 μm, preferably between 0.2 μm and 100 μm, even more preferably between 0.3 μm and 50 μm, most preferably between 0.5 μm and 10 μm, and most preferably between 1 μm and 2.5 μm. In this way, the separating layer can be irradiated particularly efficiently and precisely. The carrier substrate is preferably transparent to the laser beams.

[0035] In a preferred embodiment of the method, the pulse energy of the laser beams is between 0.01 gj and 128 gj, preferably between 0.125 gj and 64 gj, more preferably between 0.25 gj and 32 gj, most preferably between 0.5 gj and 16 gj, and most preferably between 1 gj and 8 gj. It has been found that these pulse energies can prevent damage to the product substrate.

[0036] In a preferred embodiment of the method, the laser area is smaller than 2000 gm 2 , preferably less than 500 gm 2 , more preferably less than 80 gm 2 , preferably less than 20 gm 2 , most preferably less than 1 gm 2 The area of ​​the separating layer on which the laser acts is advantageously small, allowing the adhesive properties of the separating layer to be reduced or destroyed in a targeted and localized manner. In a preferred embodiment of the method, there is a gap of at least 0.1 pm, preferably at least 1 pm, more preferably at least 5 pm, even more preferably at least 10 pm, and most preferably at least 50 pm between the areas of action of the laser beams on the separating layer, so that the areas of action of the laser beams do not overlap. This enables particularly simple and efficient separation.

[0037] In a preferred embodiment of the method, the pulse duration of the laser beams is between 10,000 ps and 1 ps, preferably between 1,000 ps and 1 ps, more preferably between 500 ps and 1 ps, most preferably between 100 ps and 1 ps, and most preferably between 50 ps and 1 ps. This pulse duration allows for targeted action for separation.

[0038] Furthermore, the invention relates to a substrate system, in particular for producing semiconductor components, at least comprising

[0039] A) a carrier substrate,

[0040] B) a separating layer arranged on the carrier substrate and

[0041] C) a product substrate arranged on the separating layer, wherein the carrier substrate can be separated from the product substrate by irradiating the separating layer with a laser unit. characterized in that the separating layer is an inorganic layer and the separating layer fixes the product substrate to the carrier substrate.

[0042] In other words, the separating layer also serves as a bonding layer. This enables a simple and carbon-free structure. In a preferred embodiment of the substrate system, at least one additional layer is arranged between the separating layer and the product substrate, and the product substrate is fixed to the carrier substrate by the at least one additional layer, wherein the at least one additional layer is inorganic.

[0043] In this way, an additional functional layer with optimal properties for the respective project can be provided. Furthermore, the additional layer is inorganic, so the advantages of a carbon-free or inorganic stack remain. If the additional layer is a bonding layer, the adhesion properties between the carrier substrate / separation layer and the product substrate can be advantageously adjusted.

[0044] In a preferred embodiment of the substrate system, it is provided that the at least one further layer is a bonding layer, wherein the bonding layer is produced from at least a first oxide layer and a second oxide layer, in particular by fusion bonding.

[0045] In a preferred embodiment of the substrate system, exclusively inorganic layers are arranged between the carrier substrate and the product substrate. This allows the substrate system to be processed independently of the requirements for carbon-containing stacks. Furthermore, contamination is reduced.

[0046] In a preferred embodiment of the substrate system, the separating layer has a separating layer thickness between 1 μm and 500 nm. The thin separating layer thickness allows for particularly simple and efficient separation of the carrier substrate. Furthermore, a particularly lightweight substrate system with a thin thickness can be advantageously provided, while simultaneously providing sufficient stabilization by the carrier substrate and fixation by the separating layer or bonding layer.

[0047] A product substrate is understood to mean any type of transferable component, in particular a wafer, a plate but also small, isolated components such as chips, dies of varying complexity, shape and functionality such as LEDs, MEMS etc. Carrier substrates are usually wafers and are suitable for supporting the layers arranged on them.

[0048] In a specific embodiment, an inorganic bonding layer, in particular made of oxide, most preferably silicon oxide, is located on the inorganic separating layer. This bonding layer was itself created from the fusion bond of two individual inorganic layers, while a further layer, in particular a functional layer, preferably made of a semiconductor material, is located on this inorganic bonding layer. Since the inorganic bonding layer is composed of two layers, it can be referred to as a layer stack. Another embodiment therefore consists of the following elements in order: carrier substrate, inorganic separating layer, layer stack of at least two inorganic layers created by a fusion bond, functional layer, or product substrate.

[0049] Furthermore, the invention relates to a device for separating a carrier substrate, at least comprising: a) a provision unit for providing the carrier substrate, b) a laser unit for irradiating a separating layer arranged on the carrier substrate, wherein at least one further layer is arranged on the side of the separating layer facing away from the carrier substrate, wherein the carrier substrate can be separated from the at least one further layer by irradiating the separating layer, characterized in that the separating layer and the further layer are inorganic.

[0050] The device is suitable for reducing the adhesive properties of the inorganic separating layer and thus detaching or separating the carrier substrate of a substrate system. The laser unit and the material of the carrier substrate and the separating layer are coordinated. In particular, the use of laser radiation in the infrared radiation range in conjunction with the most preferred material combinations delivers optimal results. The optimal combinations of laser parameters and materials are presented in the disclosure in tabular form as preferred embodiments.

[0051] An important aspect is that the method and device can be used to destroy inorganic layers or alter the adhesive properties of inorganic layers. The inorganic layers are used as separating layers to separate two bonded substrates / layers from each other or to detach layers arranged on the separating layers from the substrate or carrier substrate. Thus, substrates and layers can be separated by the separating layer. The substrate with the separating layer can thus also be used to transfer other substrates / layers.

[0052] The method, device, and substrate system can be used for processing a substrate, in particular for separating a product substrate from a carrier substrate. The term "single substrate" also includes multilayer substrate systems or substrate stacks. An important aspect of the method and device for separating a carrier substrate is the deposition of exclusively inorganic layers on at least one carrier substrate, at least one of which is a release layer.

[0053] The separation layer is smaller than 10 pm, but typically smaller than 100 nm, preferably smaller than 50 nm, more preferably smaller than 25 nm, most preferably smaller than 10 nm, most preferably smaller than 1 nm.

[0054] During the separation of the substrates, this separation layer is bombarded, in particular, by a beam, in particular a laser beam or a comparable high-intensity electromagnetic radiation source, or a particle beam. Electromagnetic beams, in particular laser beams, are preferably used, and particle beams are less preferred.

[0055] The laser parameters preferably fulfill certain conditions to cleanly separate the two substrates, or the layers arranged on the side of the separating layer facing away from the carrier substrate, by influencing the inorganic separating layer, preferably optically, with minimal stress on the product substrate and the carrier substrate. In this way, the use of organic layers in the substrate to be processed can advantageously be completely eliminated. The use of the high-temperature-resistant, inorganic separating layer thus enables processing steps that include temperature ranges that would be unattainable for organic and thus less temperature-resistant layers, especially polymer layers, without negatively affecting the holding force.

[0056] Another key aspect is how the laser energy is focused on the separation layer to reduce adhesion and / or even achieve a desirable sublimation of the separation layer. This sublimation, through additional gas pressure, forces the layers apart beyond the lateral irradiation area, thus enabling high detachment efficiency, provided the cohesion of the layers bounded above and below is higher than the adhesion of the adjacent material, thus enabling crack formation along the layers and not across them. It is necessary to coordinate the carrier substrate material, the surface properties of the carrier substrate, the laser wavelength, the laser energy, and, above all, the exposure time—primarily defined by the laser pulse duration for pulsed lasers.Since in the infrared and visible spectral range, in contrast to the ultraviolet, there are very few efficient specific transfer processes that lead to molecular cleavage through direct interaction with chemical bonds (photochemical dissociation), a "cold chemical" separation is not so easy. In this low-photon-energy, long-wave spectral range, non-linear optical effects or short thermal pulses are therefore used. The latter are intentionally kept so short that heat propagation is limited to the separation layer as much as possible within the interaction duration of the pulse. This, and the lateral limitation, also prevents the heat from acting on the useful substrate in high concentrations, but rather is dissipated either in conversion processes (e.g.in the gas phase) or is distributed over a much larger volume and cross-sectional area before dissipation, so that temperatures are reduced by several orders of magnitude and do not lead to undesirable damage to the substrates.

[0057] In particular, the pulse duration should be in the single- to double-digit picosecond range, because the heat concentration can be temporally captured within the layer at a thickness of <1 pm. On the other hand, this can suppress unwanted nonlinear processes in the carrier substrate.

[0058] A further development of the method and device describes that, in addition to the inorganic separating layer, a purely inorganic bonding layer is used to connect two substrates or layers. The inorganic bonding layer is then arranged on the side of the separating layer facing away from the carrier substrate. An inorganic bonding layer enables a further differentiation from the prior art, in which only organic layers, in particular no polymer layers, are used as bonding layers. In this way, substrates can also be transferred cleanly at higher temperatures, since neither the separating layer nor the bonding layer consists of organic material, in particular polymers that are prone to carbonization. In particular, the inorganic layers are also characterized by very high absorption (linear or non-linear), which enables particularly thin layers or even more complex layer systems.

[0059] The resulting substrate stack is preferably exclusively inorganic. Due to its inorganic structure, the substrate stack, especially the product substrate, can be processed at very high temperatures. A further advantage is the relatively high bond strength between the two substrates or the inorganic layers. Therefore, the inorganic separation layers and, if applicable, inorganic bonding layers can be made thinner. The inorganic material of the separation layer can thus be advantageously tailored to the different parameters of the laser unit. This allows the laser unit to advantageously act on the separation layer in a targeted manner, while having little or no influence on other layers and / or the carrier substrate.

[0060] The method for processing a substrate consists in the at least partial removal or destruction, or reduction of the adhesion, of the inorganic release layer. This enables the transfer of other layers and / or the separation of the substrate, in particular the carrier substrate, from another substrate.

[0061] In one embodiment of the method, an inorganic bonding layer is used in addition to the inorganic separation layer. The inorganic bonding layer connects two substrates or multiple layers. The following section describes the parameter ranges within which the method can be carried out and the device operates.

[0062] The process involves focusing a laser beam, particularly an infrared laser, onto a separation layer. The laser parameters must meet some of the following criteria.

[0063] In the method and device for separating carrier substrates, the following lasers or laser units are preferred:

[0064] -In the ultraviolet spectrum

[0065] -F2, ArF, Nd:YAG, He-Ag, KrF, XeCl, He-Cd, XeF

[0066] - In the visible spectrum

[0067] -He-Cd, Ar, copper vapor, He-Ne, Kr, ruby

[0068] -In the near infrared spectrum

[0069] -Nd:YAG, He-Ne, Er: Glass, Tm:YAG, Ho :YAG, Er:YSGG. He:YAG

[0070] -In the far infrared spectrum

[0071] -Methanol, methylamine, methyl fluoride

[0072] The wavelength of the laser beam emitted by the laser unit is between 0.1 pm and 500 pm, preferably between 0.2 pm and 100 pm, more preferably between 0.3 pm and 50 pm, most preferably between 0.5 pm and 10 pm, most preferably between 1 pm and 2.5 pm.

[0073] The following material classes and materials are preferably used for the separating layer

[0074] • Semiconductors, especially Ge

[0075] • Metals, especially

[0076] Ti, W, Al, Ta, Cu • Nitrides, especially

[0077] TiN, TaN, WN, W2N, WN2

[0078] The laser or laser unit is preferably operated in pulsed mode. A pulse duration as short as possible is of particular importance. The short pulse duration ensures local heat input into the separation layer and largely prevents heat conduction into other layers. The laser pulse duration is between 10,000 ps and 1 ps, preferably between 1,000 ps and 1 ps, more preferably between 500 ps and 1 ps, most preferably between 100 ps and 1 ps, and most preferably between 50 ps and 1 ps.

[0079] The laser spot size is the effective cross-sectional area of ​​the laser beam in the separation layer.

[0080] If the laser surface is circular, it is preferably specified by a laser surface diameter. The laser surface diameter is less than 50 pm, preferably less than 25 pm, more preferably less than 10 pm, most preferably between 5 pm, and most preferably less than 1 pm.

[0081] If the laser surface is square, it is specified by a laser surface side length. The laser surface side length is less than 100 pm, preferably less than 80 pm, even more preferably less than 50 pm, most preferably between 25 pm, and most preferably less than 15 pm.

[0082] If the laser surface is generally rectangular, it is specified by a first and a second laser surface side length. The first and / or second laser surface side length is less than 100 pm, preferably less than 80 pm, more preferably less than 50 pm, most preferably between 25 pm, and most preferably less than 15 pm.

[0083] The average laser area is less than 2000 pm 2 , preferably less than 500 pm 2 , more preferably less than 80 pm 2 , preferably less than 20 pm 2 , most preferably less than 1 pm 2. Neglecting convergence, the laser area corresponds approximately to the laser beam diameter along the path of the laser beam.

[0084] The applied energy per pulse is between 0.01 pj and 128 pj, preferably between 0.125 pj and 64 pj, more preferably between 0.25 pj and 32 pj, most preferably between 0.5 pj and 16 pj, and most preferably between 1 pj and 8 pj. The corresponding laser area energy density per pulse is calculated as the quotient of the energy per pulse to the laser area.

[0085] The roughness of the substrate surface influences the scattering of the laser radiation. The roughness should preferably be adjusted so that a maximum number of photons penetrate the substrate.

[0086] Roughness is specified either as mean roughness, root mean square roughness, or average roughness depth. The determined values ​​for mean roughness, root mean square roughness, and average roughness depth generally differ for the same measurement section or surface, but are within the same order of magnitude. Therefore, the following numerical ranges for roughness should be understood as values ​​for either mean roughness, root mean square roughness, or average roughness depth.

[0087] The roughness is greater than 10 nm, preferably greater than 100 nm, more preferably greater than 1 pm, most preferably greater than 10 pm, most preferably greater than 100 pm.

[0088] The distribution of the laser surface energy along the position is not necessarily homogeneous. The laser surface energy is characterized in particular by one of the following distribution functions:

[0089] • Gaussian distribution,

[0090] • Cauchy distribution,

[0091] • Lorentz distribution,

[0092] • Pearson distribution or • uniform distribution.

[0093] Another important aspect of the process for separating a carrier layer is the non-linear optical effects that occur when the separation layer is irradiated with the laser unit.

[0094] By correctly combining the right physical parameters, especially the substrate material, pulse length, laser wavelength, and laser energy, the behavior of the electromagnetic wave or photons in the substrate material can be adjusted so that the laser beam is focused in the separation layer. The electro-optical Kerr effect, which describes the changes in the optical properties of a material, particularly the refractive index, as a function of the electric field strength, is largely responsible for this.

[0095] The selected laser parameters and the resulting spatially focused, short-term, high-energy energy input result in at least one of the following physical effects.

[0096] The extreme temperature increase leads to thermal expansion between the separating layer and the at least one further layer or substrate adjacent to the separating layer. This effect is more effective the greater the difference in the thermal expansion coefficients of the separating layer and the adjacent layers or substrates. Expansion coefficients are temperature-dependent, but are in the order of magnitude of 10-6 Kl . A ratio is therefore useful. The absolute value of the difference between the expansion coefficient of the separating layer and the expansion coefficient of at least one adjacent at least one further layer or at least one adjacent substrate is greater than 0.1 * 10-6 Kl , preferably greater than 1.0 * 10-6 Kl , even more preferably greater than 2.5 * 10-6 Kl , most preferably greater than 5.0 * 10-6 Kl , most preferably greater than 10.0 * 10-6 Kl .If the thermal expansion exceeds a critical value, the separating layer or the carrier substrate arranged on the other side of the separating layer can be separated or detached from the at least one further layer or substrate.

[0097] By selecting a very short pulse duration, more heat can be introduced into the interface per unit of time than is dissipated into the environment. This results in sublimation and, in some cases, the formation of plasma. If the pulse duration were too long, the inorganic interface would melt. Due to the more rapid dissipation of heat into the environment, the melt quickly solidifies again, thus re-welding the interface to the environment.

[0098] Melting the inorganic separating layer is also conceivable. As already mentioned, during melting, it must be ensured that re-solidification of the melt does not cause the separating layer to fuse back to its surroundings.

[0099] In a particularly preferred procedure, the laser spots in the separation layer do not overlap. In this case, the step size between two generated laser spots must be larger than the laser spot of the laser beam. Each laser spot in the separation layer or area of ​​impact is exposed to a corresponding laser beam from the laser unit. The following parameter sets are to be mentioned as examples. For a preferred circular laser spot with a laser spot diameter of 10 pm, the step size is between 10 pm and 30 pm, preferably between 10 pm and 25 pm, even more preferably between 10 pm and 20 pm, most preferably between 10 pm and 15 pm, and most preferably between 10 pm and 12 pm.The step size should be selected that is larger than the laser surface diameter, but still large enough to effectively weaken the separation layer or improve the adhesion properties of the separation layer. For example, with a laser surface diameter of 10 pm, it can be ensured that the weakening or destruction of the separation layer occurs even with a step size of 30 pm. In particular, it is not necessary to reduce the step size to, for example, 15 pm or even 12 pm.

[0100] If the laser surfaces overlapped, the sublimated inorganic material of the separation layer of one laser surface could condense or resublimate in the adjacent laser surface, leading to renewed welding. In the prior art, the polymer would absorb the sublimated separation layer material. Therefore, an important aspect of all embodiments of the method and device for separating carrier substrates is that renewed welding can be prevented by correctly selecting the step size between two laser surfaces for a given laser surface. Furthermore, it should be noted that a laser with a correspondingly short pulse duration does not work in systems with organic layers.

[0101] The following layer systems or substrate systems are intended for separation during bonding or debonding.

[0102] In a first embodiment, the layer system consists only of an inorganic separating layer. The separating layer is preferably applied to a substrate, in particular a carrier substrate. The separating layer simultaneously acts as a bonding layer.

[0103] In a second embodiment, the layer system consists of at least one separating layer and one bonding layer. The separating layer is preferably applied to a substrate, in particular a carrier substrate. The bonding layer is applied to the separating layer. The purpose of the bonding layer is to establish a connection to another substrate (at least one further layer), in particular a product substrate, while the separating layer has the purpose of being weakened or destroyed by a laser unit.

[0104] The following layer systems or substrate systems are intended for layer transfer. At least one additional layer or substrate stack can thus be advantageously transferred using the method for separating carrier substrates.

[0105] In a third embodiment, the layer system consists of at least one separating layer and one transfer layer. The separating layer is preferably applied to a substrate, in particular a carrier substrate. The transfer layer is applied to the separating layer.

[0106] 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 applied to a substrate, in particular a separation layer. The growth layer is applied to the separation layer and is used to produce, in particular to grow, the transfer layer thereon.

[0107] 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 to a substrate, in particular a carrier substrate. The growth layer is applied to the separation layer. On the growth layer, in particular, a mask, in particular a hard material mask produced by a combination of sol-gel deposition, an imprinting process, and a curing process, is produced. A deposition process creates an overgrowth layer that grows from the growth layer through the apertures of the mask. This growth layer represents the transfer layer.

[0108] The layer systems or substrate systems mentioned can now be used to implement the separation process.

[0109] In a first method, the release layer is used to debond two substrates. For the sake of clarity and overview, the method is described using two substrates, a carrier substrate and a product substrate. However, the method can also be used to produce a substrate stack with multiple substrates. In particular, it is conceivable that the inorganic layers, in particular the release layer, vary between each two substrates. In the case of multiple substrates, there is preferably a carrier substrate and multiple product substrates attached to it. It is also conceivable that the substrate stack consists only of product substrates. In this case, however, either at least one of the product substrates should be thick enough to provide sufficient mechanical stability for the substrate stack, or the substrate stack as a whole should be thick enough to provide mechanical stability.

[0110] In a first process step, a release layer is applied to a carrier substrate. A bonding layer is applied to the release layer. A product substrate is bonded to this bonding layer.

[0111] In a second process step, the product substrate is processed.

[0112] In a third process step, the product substrate with its processed product substrate surface is bonded to another substrate, in particular a transfer substrate.

[0113] In a fourth process step, the separating layer is bombarded with a laser beam through the carrier substrate.

[0114] In a fifth process step, the carrier substrate is removed or detached.

[0115] In a special first process, layer systems consisting of a separation layer and a bonding layer are used.

[0116] A release layer is created on a carrier substrate. A bonding layer is created on the release layer. A product substrate, in particular one also provided with a bonding layer, is bonded to the bonding layer of the carrier substrate. The bond is preferably a fusion bond. The product substrate in particular already has functional units. In further process steps, the second, non-bonded, product substrate surface is processed. In particular, a re-thinning to less than 100 pm, preferably less than 50 pm, even more preferably less than 25 pm, most preferably less than 10 pm, most preferably less than 5 pm takes place. Further process steps can be carried out on the re-thinned product substrate, in particular also at high temperatures.Preferably, the second product substrate surface is oxidized and TSVs are generated, so that the second product substrate surface becomes a hybrid bond surface. A further fusion bond of a second product substrate to the second product substrate surface of the first product substrate would be conceivable. This bond is then preferably a hybrid bond, i.e. the electrical contacts of the first product substrate are connected directly to the electrical contacts of the second product substrate, while the dielectric environment of the electrical contacts is connected to one another by a fusion bond. The product substrate surface of the second product substrate preferably again has a bond layer. If the substrate stack consisting of the first and second product substrates is mechanically stable enough, the separation layer weakening method can be applied to the separation layer.The laser beam is preferably focused onto the separating layer through the carrier substrate, which is permeable or transparent to the specific wavelength of the laser. As a result, the separating layer loses its adhesive strength or is at least partially, preferably completely, removed. The two bonded product substrates can then be removed from the carrier substrate.

[0117] Only inorganic layers are used, i.e. the separation layer and all bonding layers are inorganic.

[0118] In a second process, the release liner is used to transfer a transfer layer. This process is called layer transfer.

[0119] In a first method step, a carrier substrate is provided. At least one separating layer is applied to the carrier substrate. At least one transfer layer is located on the separating layer. It is also conceivable and preferred that a growth layer is first applied to the separating layer and the transfer layer on the growth layer. It is also conceivable that the transfer layer is an overgrowth layer, which must grow through a mask. The creation of such an overgrowth layer is described in detail in the document WO2016184523A1. It is also conceivable that a diffusion layer (diffusion barrier) must be deposited between the separating layer and the transfer layer so that the two do not mix with each other in subsequent method steps.

[0120] In a second process step, the transfer layer is aligned with its free transfer layer surface to a product substrate. The product substrate may already contain functional units and / or other layers. It is also conceivable for the substrate to be a transfer substrate that only temporarily receives the transfer layer and transfers it to a product substrate in subsequent process steps. In this case, a corresponding inorganic release layer can also be created on the transfer substrate.

[0121] In a third process step, the transfer layer is bonded to the product substrate.

[0122] In a fourth process step, the separating layer is bombarded with the laser beam so that it either loses its adhesive strength and / or is at least partially destroyed.

[0123] In a fifth process step, the carrier substrate is removed, leaving the transfer layer on the product substrate. In particular, the growth layer also remains on the transfer layer.

[0124] In a sixth process step, any remaining growth layer is removed from the transfer layer.

[0125] The main difference between the exemplary separation processes is that, on the one hand, two substrates are separated from each other, and, on the other hand, a layer is transferred. All of the above processes require an inorganic separation layer.

[0126] The following is an exemplary list of preferred material and process parameters with the help of which a separation layer can be used particularly optimally for separation by laser bombardment.

[0127]

[0128] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. These schematically show:

[0129] Figure la is a side view of a substrate with a separating layer which can also act as a bonding layer,

[0130] Figure I b is a side view of a substrate with a separation layer and a separate bonding layer,

[0131] Figure 2a is a side view of a substrate with a release layer and a transfer layer,

[0132] Figure 2b is a side view of a substrate with a separation layer, a growth layer and a transfer layer,

[0133] Figure 2c shows a side view of a substrate with a separation layer, a growth layer, a mask and a transfer layer,

[0134] Figure 3a shows a first method step of an exemplary first method,

[0135] Figure 3b shows a second method step of a first method,

[0136] Figure 3c shows a third method step of a first method,

[0137] Figure 3d shows a fourth method step of a first method,

[0138] Figure 3e shows a fifth method step of a first method,

[0139] Figure 4a shows a first method step of an exemplary first special method,

[0140] Figure 4b shows a second method step of a first special method,

[0141] Figure 4c shows a third method step of a first special method,

[0142] Figure 4d shows a fourth method step of a first special method,

[0143] Figure 4e shows a fifth method step of a first special method,

[0144] REVISED SHEET (RULE 91) ISA / EP Figure 4f a sixth step of a first specific procedure,

[0145] Figure 4g shows a seventh process step of a first special process,

[0146] Figure 4h shows an eighth process step of a first special process,

[0147] Figure 4i shows a ninth process step of a first special,

[0148] Figure 5a shows a first method step of an exemplary second,

[0149] Figure 5b shows a second method step of a second method,

[0150] Figure 5c shows a third method step of a second method,

[0151] Figure 5d shows a fourth method step of a second method,

[0152] Figure 5e shows a fifth method step of a second method and

[0153] Figure 5f shows a sixth method step of a second method.

[0154] In the figures, identical components or components with the same function are marked with the same reference numerals.

[0155] Figures 1 a-1 b show two basic substrate systems or layer systems on a carrier substrate 1, whose function is to provide a separating layer 2 and a bonding layer 14. All layers are inorganic.

[0156] Figure 1a shows a side view of a carrier substrate 1 to which a separating layer 2 has been applied. The separating layer 2 is inorganic. The separating layer 2 is deposited directly on the substrate 1 using a method known from the prior art. This combination of carrier substrate 1 and separating layer can be used to bond a second substrate. In this case, the separating layer 2 acts not only as a separating layer, but simultaneously also as a bonding layer 14. In this case, the carrier substrate 1 would be a carrier substrate whose task is to mechanically stabilize the second substrate. Figure 1b shows a side view of a carrier substrate 1 to which a separating layer 2 has been applied. The separating layer 2 is inorganic. On the separating layer 2 there is a bonding layer 14, to which another substrate, which preferably also has a bonding layer 14, can be bonded.The bonding layer 14 is inorganic, preferably a dielectric, in particular an oxide layer, most preferably a silicon oxide layer.

[0157] Figures 2a-2c show four basic substrate systems or layer systems. In addition to the inorganic separating layer, these have at least one further layer. Furthermore, the carrier substrate provides the separating 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 to another substrate (not shown), in particular a product substrate 6, and not to bond the carrier substrate 1 to a substrate (not shown), in particular product substrate 6. The transfer layer 3 is designed to be as wide as possible. Thus, a transfer layer 3 can be understood as a single layer, but also as a layer system. The transfer layer 3 can, for example, also be an embossed layer with structures. The transfer layer 3 can, for example, be a layer consisting of several lenses, microchips, MEMS, LEDs, etc.The thickness of the transfer layer 3 can be from a few angstroms to a few millimeters.

[0158] Figure 2a shows a side view of a carrier substrate 1 onto which a release layer 2 has been applied. The release layer 2 is inorganic. A transfer layer 3 is located on the release layer 2, which is to be transferred to another substrate (not shown), in particular a product substrate 6.

[0159] Figure 2b shows a side view of a carrier substrate 1 onto which a separating layer 2 has been applied. The separating layer 2 is inorganic. A growth layer 4 is located on the separating layer 2. A transfer layer 3 is generated on the growth layer 4. The transfer layer 3 can be transferred to another substrate (not shown), in particular product substrate 6, in a process. Figure 2b is a special case of Figure 2a. In general, a separating layer 2 will not offer the necessary conditions to generate a desired transfer layer 3, so that first a growth layer 4 must be generated, on which the transfer layer 3 can then be grown.

[0160] Figure 2c shows a side view of a carrier substrate 1 onto which a release layer 2 has been applied. The release layer 2 is inorganic. A growth layer 4 is located on the release layer 2. A mask 5 is applied to the growth layer 4. The mask 5 is preferably embossed and cured directly from a liquid, preferably a sol-gel, using an embossing process. However, the mask 5 can be produced using any other method. The material for a transfer layer 3 is then deposited. The material of the transfer layer 3 is first deposited in the openings of the mask 5 and grows beyond these to form a 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 product substrate 6, in a release process. Figure 2c is a special case of Figure 2b.In addition to the growth layer 4, a mask 5 was also created. The advantage of producing such a transfer layer 3 is that it is largely defect-free.

[0161] A bonding layer 14 can also be applied to the aforementioned transfer layers 3 in order to increase the adhesive strength to the substrate (not shown), in particular the product substrate 6 onto which the transfer layer 3 is to be transferred. Since the illustration of such a bonding layer 14 was already shown in Figures 1a-1b, it is omitted in Figures 2a-2c for the sake of clarity.

[0162] Figure 3a shows a side view of a first process step of a first possible process. A carrier substrate 1, on which a separating layer 2 and a bonding layer 14 are located (see Figure 1b), is aligned and bonded to a product substrate 6. The product substrate 6 is bonded to the bonding layer 14 via a first product substrate surface. In the further process, the carrier substrate 1 has the task of mechanically stabilizing the product substrate 6.

[0163] Figure 3b shows a side view of a second process step of a first possible process. The second product substrate surface of the product substrate 6 is being processed. A re-thinning of the product substrate 6 is shown as an example. However, countless other processes can be performed in this process step. In particular, LEDs, MEMS, microcontrollers, etc. can be manufactured. To keep the illustration as simple as possible, these processes are omitted.

[0164] Figure 3c shows a side view of a third process step of a first possible process. The product substrate 6 is aligned and bonded to a transfer substrate 7 via its processed second product substrate surface. In the present case, the transfer substrate 7 is a film 9 that has been stretched onto a frame 8. However, the transfer substrate 7 can be a different substrate, in particular another carrier substrate 1 or another product substrate 6.

[0165] Figure 3d shows a side view of a fourth method step of a first possible method. A laser 10 is used to focus a laser beam 11 onto the separating layer 2. By using a laser 10 with appropriate laser parameters, in particular a very short pulse duration in the picosecond range, the separating layer 2 is dissolved or the adhesion strength to the carrier substrate 1 is reduced at least to such an extent that the carrier substrate 1 can be removed.

[0166] Figure 3e shows a side view of a fifth process step of a first possible process. The product substrate 6 is located on the transfer substrate 7 after the carrier substrate 1 (not shown, see Figure 3d) has been removed. The release layer 2 has been removed or has already been automatically removed during the process step shown in Figure 3d.

[0167] The following figures show a second process that is of crucial importance in the semiconductor industry. The second process is generalized and abstracted as much as possible. However, it is characterized by the use of an inorganic separation layer 2 and a separate bonding layer 14.

[0168] Figure 4a shows a side view of a first process step of a first specific process. A separating layer 2 is applied to a carrier substrate 1. A bonding layer 14 is created on the separating layer 2 (see Figure 1b). The bonding layer 14 is preferably a dielectric layer, most preferably an oxide, most preferably a silicon oxide.

[0169] Figure 4b shows a side view of a second method step of a first specific method. A product substrate 6 already provided with functional units 12, the product substrate surface 6o of which has preferably been coated with a bonding layer 14, is aligned relative to the carrier substrate 1. The functional units 12 preferably have electrical contacts 15. The use of a bonding layer 14 on the product substrate 6 can be omitted if the product substrate 6, with its product substrate surface 6o, adheres well enough to the bonding layer 14 of the carrier substrate 1. Preferably, however, the bonding layer 14 is present on the product substrate 6; even more preferably, the materials of the two bonding layers 14 on the carrier substrate 1 and on the product substrate 6 are identical. Most preferably, the bonding layers are oxides.

[0170] Figure 4c shows a side view of a third process step of a first specific process. The product substrate 6 is bonded to the carrier substrate 1 via the bonding layers 14. If the bonding layers are oxide, then this is a fusion bond. Before any heat treatment, it is referred to as a pre-bond. After heat treatment, after covalent bonds have formed between the contacting bonding layer surfaces of the bonding layers 14, it is referred to as a fusion bond. The heat treatment step is not shown. It is important that the product substrate 6 adheres well enough to the carrier substrate 1 to allow further processing. If the adhesive strength is high enough without heat treatment, it is even conceivable to perform no heat treatment.

[0171] Figure 4d shows a side view of a fourth process step of a first specific process. Here, the product substrate 6 is rethinned. Rethinning is often desired in order to minimize the thickness of the final product as much as possible.

[0172] Figure 4e shows a side view of a fifth method step of a first specific method. The thinned product substrate surface of the product substrate 6 is coated with a bonding layer 14, in particular a dielectric layer, preferably an oxide, most preferably a silicon oxide. Through silicon vias (TSVs) 13 are created through the bonding layer 14 and the product substrate 6 in order to make the electrical contacts 15 of the functional units 12 accessible and available at the surface of the bonding layer 14.

[0173] Figure 4f shows a side view of a sixth method step of a first specific method. A second product substrate 6', also provided with functional units 12, TSVs 13, and a bonding layer 14, is aligned relative to the first product substrate 6 or the carrier substrate 1. The second product substrate 6' will likely also be fixed to a carrier substrate 1', preferably even with the aid of the method. However, in order to keep the figures clear, a carrier substrate 1' with a corresponding separating layer 2 and bonding layer 14 or any other layer system is omitted. Alignment is performed using alignment marks (not shown) and specially designed alignment systems with very precise optics (not shown).

[0174] Figure 4g shows a side view of a seventh process step of a first specific process. The two product substrates 6, 6' are bonded together via their bonding layers 14. In this process, the TSVs 13 are correctly connected to each other, enabling an electrical connection between the functional units 12 of the product substrates 6, 6'.

[0175] Figure 4h shows a side view of a seventh method step of a first specific method. A laser 10 is used to focus a laser beam 11 onto the separating layer 2. By using a laser 10 with appropriate laser parameters, in particular a very short pulse duration in the picosecond range, the separating layer 2 is dissolved or the adhesion to the carrier substrate 1 is reduced at least to such an extent that the carrier substrate 1 can be removed.

[0176] Figure 4i shows a side view of a seventh process step of a first specific process. A permanently interconnected substrate stack 16 consisting of two product substrates 6, 6' can be seen. This substrate stack can be further processed accordingly. It was mentioned in Figure 4i that a carrier substrate 1' was omitted for clarity. On such a carrier substrate 1', the substrate stack 16 could be easily transported and / or further processed.

[0177] In Figures 4a-4i, a separating layer 2 with a bonding layer 14 located thereon was used and described. According to the general embodiment of Figure 1a, separating layer 2 and bonding layer 14 can also be identical.

[0178] Figure 5a shows a side view of a first method step of a second method, in which a carrier substrate 1 is provided with at least one separating layer 2 and a transfer layer 3. Preferably, a growth layer 4 is also present on the separating layer 2 in order to produce, in particular grow, the transfer layer 3.

[0179] Figure 5b shows a side view of a second process step of a second process, in which a product substrate 6, preferably with functional units 13, is aligned relative to the carrier substrate. Alignment is again performed using alignment marks (not shown) and special alignment systems (not shown).

[0180] Figure 5c shows a side view of a third process step of a second process, in which the product substrate 6 is contacted with the transfer layer 3. In the present case, it is desired that the transfer layer 3 directly contacts the functional units 12. It is conceivable, for example, that the transfer layer 3 is structured in later process steps. The transfer layer 3 could, for example, be a graphene layer grown on a copper growth layer 4. An RDL layer (redistribution layer) could then be created from the transfer layer 3 on the product substrate surface of the product substrate 6.

[0181] Figure 5d shows a side view of a fourth method step of a second method in which a laser beam 11 of a laser 10 is focused onto the separating layer 2.

[0182] Figure 5e shows a side view of a fifth method step of a second method in which the carrier substrate 1 (not shown, see Figure 5d) was removed.

[0183] Figure 5f shows a side view of a sixth process step of a second process in which the growth layer 4 was still removed. List of reference symbols

[0184] carrier substrate

[0185] Separating layer

[0186] transfer layer

[0187] growth layer

[0188] Mask, 6' product substrate

[0189] Transfer substrate

[0190] Frame

[0191] Foil 0 Laser unit, laser 1 Laser beam 2 Functional unit 3 TSV 4 Bond layer 5 Electrical contacts 6 Substrate stack

Claims

Patent claims 1. Method for separating a carrier substrate (1) from a Product substrate (6) comprising at least the following steps: i) providing the support substrate (1) and the product substrate (6) with an intermediate separating layer (2), wherein the separating layer fixes the product substrate to the support substrate, ii) irradiating the separating layer (2) with laser beams (11) of a laser unit (10) and iii) separating the support substrate (1) from the product substrate (6), characterized in that the separating layer (2) is inorganic.

2. Method according to claim 1, wherein at least one further layer (3 , 4, 5, 6' , 7, 14) is arranged 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. Method according to at least one of the preceding claims, wherein exclusively inorganic layers are arranged between the product substrate and the support substrate.

4. Method according to at least one of the preceding claims, wherein during the irradiation in step ii) the laser beams (1 1 ) emitted by the laser unit ( 10) first penetrate the support substrate ( 1 ) and then strike the separating layer (2).

5. Method according to at least one of the preceding claims, wherein the at least one further layer (3 , 4, 5, 6' , 7, 14) is a silicon oxide layer which acts as a bonding layer ( 14 ).

6. Method according to at least one of the preceding claims, wherein the at least one further layer (3 , 4, 5, 6' , 7, 14) is produced from a first oxide layer and a second oxide layer, in particular by fusion bonding.

7. Method according to at least one of the preceding claims, wherein the separating layer (2) is made of a metal or nitride, preferably TiN.

8. Method according to at least one of the preceding claims, wherein the laser beams ( 1 1 ) have a wavelength between 0.1 pm and 500 pm, preferably between 0.2 pm and 100 pm, more preferably between 0.3 pm and 50 pm, most preferably between 0.5 pm and 10 pm, most preferably between 1 pm and 2.5 pm.

9. Method according to at least one of the preceding claims, wherein the pulse energy of the laser beams ( 1 1 ) is between 0.01 pJ and 128 pJ, preferably between 0.125 pJ and 64 pJ, more preferably between 0.25 pJ and 32 pJ, most preferably between 0.5 pJ and 16 pJ, and most preferably between 1 pJ and 8 pJ.

10. Method according to at least one of the preceding claims, wherein the laser area is less than 2000 pm 2 , preferably smaller than 500 pm 2, preferably smaller than 80 pm 2 , preferably smaller than 20 pm 2 , preferably smaller than 1 pm 2 is. 1 1. Method according to at least one of the preceding claims, wherein the area of ​​effect of the laser beams ( 1 1 ) on the separating layer (2) is at least 0.1 pm, preferably at least 1 pm, more preferably at least 5 pm, even more preferably at least 10 pm, most preferably at least 50 pm, so that the area of ​​effect of the laser beams ( 1 1 ) does not overlap.

12. Method according to at least one of the preceding claims, wherein the pulse duration of the laser beams ( 1 1 ) is between 10000 ps and 1 ps, preferably between 1000 ps and 1 ps, more preferably between 500 ps and 1 ps, most preferably between 100 ps and 1 ps, most preferably between 50 ps and 1 ps.

13. Substrate system, in particular for the production of semiconductor components, at least comprising, A) a carrier substrate ( 1 ), B) a separating layer (2) arranged on the support substrate ( 1 ) and C) a product substrate (6) arranged on the separating layer, wherein the carrier substrate (1) can be separated from the product substrate (6) by irradiating the separating layer (2) with a laser unit (10), characterized in that the separating layer (2) is inorganic and the separating layer (2) fixes the product substrate (6) to the carrier substrate.

14. Substrate system according to claim 13, wherein at least one further layer (3 , 4, 5, 6' ,7 , 14) is arranged between the separating layer (2) and the product substrate (6) and the product substrate (6) is fixed to the support substrate (1) by the at least one further layer (3, 4, 5, 6' ,7 , 14), wherein the at least one further layer is inorganic.

15. Substrate system according to claim 14, wherein the at least one further layer is a bond layer ( 14), wherein the bond layer ( 14) is produced from at least a first oxide layer and a second oxide layer, in particular by fusion bonding.

16. Substrate system according to at least one of the preceding claims, wherein exclusively inorganic layers are arranged between the support substrate (2) and the product substrate (6).

17. Substrate system according to at least one of the preceding claims, wherein the separating layer (2) has a separating layer thickness between 10m and 500nm.

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