DE102015004603A1 - Combined wafer fabrication process with laser treatment and temperature-induced stresses - Google Patents

Abstract

The present invention relates to a method for producing solid state layers. The inventive method preferably comprises at least the steps: providing a solid body (2) for separating at least one solid layer (4), generating defects by means of radiation from at least one radiation source (18), in particular a laser, in the internal structure of the solid body for prescribing a Ablöseebene (8), along which the solid state layer (4) from the solid (2) is separated, separating the solid layer (4) of the solid (2) by means of a along the release plane (8) guided crack, whereby the solid body (2) a Surface is exposed and on the solid layer, a surface is exposed, wherein after separating the solid layer (4) by means of a tempering means a radiation treatment for smoothing the surface structure of the exposed surface of the separated solid layer (4) and / or the exposed surface of the solid (2) is carried out.

Description

The present invention relates to a method for producing solid-state layers according to the subject matter of claim 1, to a wafer produced by means of this method (claim 12) and according to claim 13 to a plant for producing solid-state layers.

In many technical areas (eg microelectronics or photovoltaic technology), materials such. As silicon, germanium or sapphire, often in the form of thin slices and plates (so-called wafer) needed. By default, such wafers are currently produced by sawing from an ingot, resulting in relatively large material losses ("kerf-loss"). Since the starting material used is often very expensive, there are strong efforts to produce such wafers with less material and thus more efficient and cost-effective.

For example, with the currently customary methods, almost 50% of the material used is lost as "kerf loss" alone in the production of silicon wafers for solar cells. Worldwide, this represents an annual loss of over 2 billion euros. Since the cost of the wafer accounts for the largest share of the cost of the finished solar cell (over 40%), the cost of solar cells could be significantly reduced through improvements in wafer manufacturing.

Particularly attractive for such a wafer production without kerf-loss ("kerf-free wafering") appear methods that do without the conventional sawing and z. B. by using temperature-induced voltages directly thin wafers can split off from a thicker workpiece. These include in particular methods, such as. In PCT / US2008 / 012140 and PCT / EP2009 / 067539 where a polymer layer applied to the workpiece is used to generate these stresses.

The polymer layer has in the mentioned method a compared to the workpiece by about two orders of magnitude higher thermal expansion coefficient. In addition, by utilizing a glass transition, a relatively high modulus of elasticity in the polymer layer can be achieved, so that sufficiently high voltages can be induced in the layer system polymer layer workpiece by cooling in order to enable the removal of wafers from the workpiece.

When a wafer is split off from the workpiece, polymer still adheres to one side of the wafer in each of the methods mentioned. The wafer bends very strongly in the direction of this polymer layer, which makes controlled separation difficult, and z. B. can lead to thickness variations of the split-wafer. In addition, the high curvature makes further processing difficult and may even break the wafer.

When using the methods of the prior art, the wafers produced usually each have larger variations in thickness, wherein the spatial thickness distribution often shows a pattern with fourfold symmetry. The total thickness variation (TTV) over the entire wafer is often greater than 100% of the average wafer thickness (eg, a wafer of, for example, 100 microns average thickness, eg, at its thinnest 50 microns thick and 170 microns thick at its thickest point, has a TTV of 170-50 = 120 microns, which corresponds to a total thickness variation of 120% relative to its mean thickness). Wafers with such large thickness variations are not suitable for many applications. In addition, in the most common fourfold thickness distribution patterns, the regions of greatest variability unfortunately lie in the middle of the wafer where they are most disturbing.

In addition, in the method according to the current state of the art during the fracture propagation during the splitting off, undesired oscillations in the layer systems involved occur, which unfavorably influence the course of the fracture front and in particular can lead to significant thickness fluctuations of the split-off wafer.

In addition, it is difficult in the previous methods to ensure a reproducibly good thermal contact over the entire surface of the polymer layer. Due to the low thermal conductivity of the polymers used, locally insufficient thermal contact can lead to unwanted, significant local temperature deviations in the layer system, which in turn adversely affects the controllability of the generated stress fields and thus the quality of the produced wafers.

Furthermore, from the document DE 196 40 594 A1 a method of separating semiconductor materials by means of light-induced interfacial decomposition and devices made therewith, such as patterned and freestanding semiconductor layers and devices. The method according to the DE 196 40 594 A1 involves the illumination of interfaces between substrate and semiconductor layer or between semiconductor layers, whereby the light absorption at the interface or in an absorption layer provided for this purpose Material decomposition leads. The selection of the interface or semiconductor layer, which is brought to decomposition, takes place by the choice of the wavelength of light and light intensity, the direction of irradiation or the incorporation of a thin sacrificial layer during material production. This method has the disadvantage that high energy doses must be used to destroy entire layers, whereby the energy requirements and thus the cost of the process are very high.

Furthermore, by the documents EP000002390044B1 . EP000001498215B1 . EP000001494271 B1 . EP000001338371B1 discloses a method in which the laser is used for vertically separating workpieces.

Furthermore, laser-assisted methods for generating defects within a wafer are known. With a focused laser multiphoton excitations are achieved in the depth, with which a damage in the depth is possible without damage to the material entry.

Typically, lasers with an ns pulse duration (nanosecond pulse duration) are used so that a strong interaction of the heated material with the laser can occur. Typically, this occurs via a photon-phonon interaction, which has a significantly higher absorption than the multi-photon excitation.

Such a method is for example by Ohmura et. al. (Journal of Achievements in Materials and Manufacturing Engineering, 2006, vol 17, p. 381 ff) known. The by Ohmura et al. The proposed wafer treatment serves to generate crack guide lines by a defect generation within the wafer, as they are partially provided when separating wafer elements of a wafer plate. In this case, the defects generated in this method extend in the vertical direction, as a result of which the connection structure between the individual wafer elements experiences elongated weakenings at right angles to the main surface of the wafer elements. The elongated weakenings have expansions of> 50 μm.

The advantage exploited for the separation of wafer elements, namely the generation of expansions with a vertical extent of> 50 μm, prevents a transfer of this type of defect generation to processes for splitting off one or more wafer layers from a solid. On the one hand, when the elongated defects are distributed over the wafer surface, a material layer is created inside the solid body which can only be used for guiding cracks, but is unsuitable for later use and therefore represents rejects. On the other hand, this committee must, for. B. be removed by polishing, whereby an additional expense would arise. It is thus the object of the present invention to provide a process for the production of solid layers or solids, which allow the cost-effective production of solid plates or uneven solids with a desired thickness distribution, wherein the vertical damage is minimized around the crack plane.

It is thus the object of the present invention to provide a method for producing solid-state layers, which enables the cost-effective production of solid-state plates or wafers with a uniform thickness and a smooth surface, in particular with a TTV of less than 120 micrometers. It is a further object of the present invention to provide a method of making one or more solid layers wherein a crack propagation plane is generated by a laser within a solid, wherein the individual defects forming the crack propagation plane have a vertical extent of less than 50 μm should have.

The aforementioned object is achieved by a method according to claim 1 for producing solid-state layers. The method according to the invention preferably comprises at least the steps: providing a solid for separating at least one solid layer, generating defects by means of radiation from at least one radiation source, in particular a laser, in the internal structure of the solid to specify a release plane along which the solid layer separates from the solid separating the solid layer from the solid by means of a crack along the release plane, thereby exposing a surface to the solid and exposing a surface to the solid layer, wherein after separating the solid layer by means of a tempering means, radiation treatment is provided to smooth the surface structure of the exposed surface the separated solid layer and / or the exposed surface of the solid is carried out.

This solution is advantageous because, due to the radiation source, the release layer or defect layer can be generated in the solid through which the crack propagates during the crack propagation, which results in the realization of very small TTVs, in particular less than 200 micrometers or 100 micrometers or less than 80 microns or less than 60 microns or less than 40 microns or less than 20 microns or less than 10 microns or less than 5 microns, especially 4, 3, 2, 1 microns. The radiation of the wafer thus creates in a first Step a kind of perforation in the interior of the solid along which the crack propagation occurs in a second step or along which the solid layer is separated from the solid.

Further advantageous embodiments are the subject of the following description and / or the dependent claims.

In particular, it is advantageous if the additional laser treatment is carried out in the form of ultra-short-time annealing, the laser beam being applied to the separated solid-state layer in the range of milliseconds and microseconds.

According to a preferred embodiment of the present invention, the laser has a pulse duration of less than 10 ps, more preferably less than 1 ps, and most preferably less than 500 fs.

The stresses for detaching the solid-state layer are generated by the solid body by the thermal loading of the receiving layer, in particular a polymer layer, according to a preferred embodiment of the present invention. The thermal application preferably represents a cooling of the receiving layer or polymer layer to or below the ambient temperature and preferably below 10 ° C. and more preferably below 0 ° C. and more preferably below -10 ° C. The cooling of the polymer layer is most preferably such that at least a part of the polymer layer, which preferably consists of PDMS, undergoes a glass transition. The cooling can be a cooling to below -100 ° C, the z. B. by means of liquid nitrogen is effected. This embodiment is advantageous because the polymer layer contracts as a function of the temperature change and / or experiences a gas transfer and transfers the resulting forces to the solid, whereby mechanical stresses can be generated in the solid, which trigger a crack and / or crack propagation lead, wherein the crack propagates first along the first release plane for splitting off the solid layer.

According to a preferred embodiment of the present invention, the solid body is disposed on a holding layer for holding the solid body, wherein the holding layer is disposed on a first planar surface portion of the solid, wherein the first planar surface portion of the solid body is spaced from a second planar surface portion of the solid the polymer layer is arranged on the second planar surface portion and wherein the release plane is aligned parallel to the first planar surface portion and / or the second planar surface portion or is generated in parallel.

This embodiment is advantageous since the solid body is arranged at least in sections and preferably completely between the holding layer and the polymer layer, whereby the stresses for crack generation or crack propagation into the solid body can be introduced by means of one of these layers or by means of both layers.

At least or one radiation source is configured in accordance with another preferred embodiment of the present invention for providing the radiation to be introduced into the solid state such that the rays emitted by it generate the defects at predetermined locations within the solid state. This embodiment is advantageous because defects in the solid can be generated extremely accurately by means of a radiation source, in particular by means of a laser.

In particular, two applications arise for the method, referred to below as "wafering" and "thinning". In wafering, the process is commonly used to strip a thicker layer from an even thicker semiconductor block, typically a wafer (with the industry specific thicknesses) from an ingot. "Thinning" uses the process to split off a very thin layer from a wafer, which corresponds to the current process of grindings, but with the advantage that the unneeded material remains intact and can be reused. A clear separation of "thinning" and "wafering" is complicated because z. B. the "thinning" can also be done by acting on the back of a wafer, so that although a thin layer is formed, but the laser penetrates deep into the material.

For the "thinning" case:
The radiation source is adjusted in accordance with a further preferred embodiment of the present invention such that the rays emitted by it penetrate into the solid body to produce the release plane to a defined depth, in particular <100 μm. Preferably, the Ablöseebene spaced parallel to an outer and preferably flat surface of the solid is formed. Preferably, the release plane is less than 100 microns, and preferably less than 50 microns, and more preferably less than or equal to 20, 10, 5, or 2 microns spaced from the planar surface of the solid within the solid. Thus, the release plane is preferably formed in the form of a plane created from defects, wherein the defects are formed less than 100 microns, and preferably less than 50 microns, and more preferably less than 20, 10 or 2 microns spaced from the planar surface of the solid within the solid ,

For the "wafering" case:
In accordance with a further preferred embodiment of the present invention, the radiation source is set in such a way that the rays emitted by it for generating the release plane penetrate to a defined depth, in particular> 100 μm, into the solid. Preferably, the Ablöseebene spaced parallel to an outer and preferably flat surface of the solid is formed. Preferably, the release plane is more than 100 microns, and preferably more than 200 microns, and more preferably more than 400 or 700 microns spaced from the planar surface of the solid formed within the, solid. Thus, the release plane is preferably formed in the form of a plane created from defects, wherein the defects are formed more than 100 microns, and preferably more than 200 microns, and more preferably more than 400 or 700 microns spaced from the planar surface of the solid within the solid.

The solid is applied according to a further preferred embodiment of the present invention with a predetermined wavelength and / or power, wherein the predetermined wavelength is preferably adapted to the respective material or substrate. This embodiment is advantageous because the defect size can be influenced by the wavelength and / or the power.

According to a further preferred embodiment of the present invention, the solid has silicon and / or gallium or perovskite, and the polymer layer and / or the holding layer consist at least partially and preferably completely or more than 75% of polydimethylsiloxanes (PDMS) at least partially planar surface of a stabilizing device is arranged, which consists at least partially of at least one metal. The stabilizing device is preferably a plate, in particular a plate comprising or consisting of aluminum. This embodiment is advantageous because the solid state is defined or held by the stabilization device and the holding layer, as a result of which the stresses can be generated very accurately in the solid.

According to a further preferred embodiment of the present invention, the stresses in the solid body can be adjusted or generated in such a way that the crack initiation and / or the crack propagation is controllable for producing a topography of the surface resulting in the crack plane. The stresses are thus preferably in different areas of the solid preferably at least temporarily differently strong generated. This embodiment is advantageous since the topography of the generated or separated solid-state layer can be advantageously influenced by controlling the crack initiation and / or the crack progression.

According to another preferred embodiment of the present invention, the defects provide at least one crack guiding layer, wherein the at least one crack guiding layer has a shape deviating from a planar shape. This solution is advantageous because the solid layers produced or the solids generated can have a different shape from a flat layer. Thus, not only planar layers but also three-dimensional bodies can be formed or produced from a workpiece by means of a crack propagation. Due to the manufacturing process, solids produced in this manner have a very advantageous surface which can be processed only slightly or not. So z. B. optical elements, such as. As a spade or a lens in a single-stage or multi-stage, in particular two or three-stage, split process produced.

The shape of the crack guiding layer thus has according to a preferred embodiment of the present invention, at least in sections, the contour of a three-dimensional object, in particular a lens or a spade on.

According to a preferred embodiment of the present invention, the defects are generated by a defect generator and the radiation source, respectively, wherein the defect generator is configured to generate the defects at a constant distance from the defect generator in the workpiece, with the workpiece and the defect generator being so relative to each other it is preferable that the defects generated by the defect generating device are generated in the crack guiding layer, whereby the defect generating device and the workpiece are repositioned only two-dimensionally with each other during the defect generation. The defect generating device is thus preferably repositioned relative to the workpiece or the workpiece is repositioned with respect to the defect generating device or the defect generating device and the workpiece are both repositioned to each other.

This embodiment is advantageous since the radiation source or the defect-producing device only has to be repositioned for defect generation and no modification of the defect-generating device has to be effected, in particular no changed defect-introduction depth has to be determined and set.

The defects are in accordance with a further preferred embodiment by means of a The defect generating device is configured such that the defects are generated at a time varying distance to the defect generating device in the workpiece, depending on the distance of the defect generating device to the defect to be generated at least temporarily a modification of the defect generating device is effected, in particular an altered defect introduction depth is determined and adjusted. This embodiment is advantageous because preferably no tilting device has to be provided for tilting the workpiece.

The solid preferably comprises a material or a material combination of one of the main groups 3, 4 and 5 of the Periodic Table of the Elements, such as. Si, SiC, SiGe, Ge, GaAs, InP, GaN, Al 2 O 3 (sapphire), AlN. Particularly preferably, the solid has a combination of elements occurring in the third and fifth group of the periodic table. Conceivable materials or material combinations are z. B. gallium arsenide, silicon, silicon carbide, etc. Furthermore, the solid may have a ceramic (eg., Al2O3 - alumina) or consist of a ceramic, preferred ceramics are z. Perovskite ceramics (such as Pb, O, Ti / Zr containing ceramics) in general, and lead magnesium niobates, barium titanate, lithium titanate, yttrium aluminum garnet, especially yttrium aluminum garnet crystals for solid state laser applications , SAW ceramics (surface acoustic wave), such. As lithium niobate, gallium orthophosphate, quartz, calcium titanate, etc. in particular. The solid body thus preferably has a semiconductor material or a ceramic material or particularly preferably the solid body consists of at least one semiconductor material or a ceramic material. It is also conceivable that the solid has a transparent material or partially made of a transparent material, such. B. sapphire, consists or is made. Other materials that come here as a solid material alone or in combination with another material in question are, for. "Wide band gap" materials, InAlSb, high temperature superconductors, especially rare earth cuprates (eg YBa2Cu3O7).

According to another preferred embodiment of the present invention, the radiation source or a part of the radiation source is designed as a femtosecond laser (fs laser). This solution is advantageous because the use of an fs laser minimizes the vertical spread of the perturbed material. By using an fs laser, it is possible to introduce defects in the workpiece very accurately. The wavelength and / or the energy of the fs laser are preferably selected depending on the material.

According to a further preferred embodiment of the present invention, the energy of the radiation source, in particular of the laser beam, in particular of the fs laser, is selected so that the damage propagation in the solid or in the crystal is less than three times the Reyleighlänge, preferably smaller than the Reyleighlänge and particularly preferred is less than a third of the Reyleigh length.

The wavelength of the laser beam, in particular of the fs laser, is selected according to a further preferred embodiment of the present invention such that the absorption of the solid or of the material is less than 10 cm ^-1 and preferably less than 1 cm ^-1 and particularly preferably less than 0.1 cm ^-1 .

The individual defects result according to a further preferred embodiment of the present invention in each case from one of the radiation source, in particular the laser, in particular a fs laser, caused multi-photon excitation.

According to a further preferred embodiment of the present invention, the tempering device has a multiplicity of light sources, in particular halogen lamps, and at least one reflector for reflecting light beams, wherein the tempering device for exposing the surface structure of the exposed surface of the solid layer or the exposed surface of the solid body to the exposed surface Aligned surface of the solid state layer or the exposed surface of the solid, that between the exposed surface of the solid state layer or the exposed surface of the solid and the reflector, the light sources are arranged. This embodiment is advantageous since the tempering device and the surface to be treated can be aligned with one another in a very simple and fast manner.

The exposed surface of the solid-state layer or the exposed surface of the solid is according to another preferred embodiment of the present invention by means of the tempering device to a temperature of more than 1000 Kelvin, in particular more than 2000 Kelvin or more than 3000 Kelvin tempered. This embodiment is advantageous because, depending on the material of the solid, a suitable temperature control can be effected, as a result of which the solid-state material preferably melts or liquefies in the region of the treated surface or the exposed outer molecule layers. As a result of melting or liquefaction, the smoothing of the surface structure results.

According to a further preferred embodiment of the present invention, the heating rate of the tempering device is more than 5000 Kelvin / second, in particular more than 10000 Kelvin / second. This embodiment is advantageous since a very high temperature for smoothing the surface can be generated in a very short time.

The surface structure of the exposed surface of the solid layer or the exposed surface of the solid according to another preferred embodiment of the present invention after smoothing has an average roughness (R _a ) less than 1/4 or less than 1/5 or less than 1/8 or less than 1/10 or less than 1/12 or less than 1/15 or less than 1/18 or less than 1/20 of the wavelength of the radiation emitted by the radiation source, in particular laser beams , wherein the wavelength of the radiation is less than 2.5 μm, in particular less than 2 μm or less than 1.5 μm or less than 1.2 μm. This embodiment is advantageous because it provides a surface with a very low average roughness.

The invention further relates to a wafer which is produced by a method according to one of claims 1 to 12.

The aforementioned object is also achieved by a plant for producing solid-state layers. The system according to the invention preferably comprises at least one holding device for providing, in particular holding, a solid from which at least one solid layer can be separated, a radiation source, in particular a laser, for generating defects by means of radiation in the internal structure of the solid for predetermining a release plane, along which the solid-state layer can be separated from the solid, tempering means for tempering, in particular cooling, a voltage generating layer generated or arranged on the solid for generating voltages for separating the solid body from the solid by means of a crack generated by the tensions and along the release plane, thereby a surface is uncovered on the solid body and a surface is exposed on the solid-state layer, and at least one tempering device, whereby by means of the tempering device a radiation treatment for smoothness n the surface structure of the exposed surface of the separated solid layer and / or the exposed surface of the solid body is feasible.

Furthermore, the subjects of the publications PCT / US2008 / 012140 and PCT / EP2009 / 067539 fully incorporated by reference into the subject matter of the present application. Likewise, the objects of all other filed on the filing date of the present patent application by the Applicant also filed and related to the field of producing solid-state layers further patent applications are fully made subject of the present patent application.

Further advantages, objects and characteristics of the present invention will be explained with reference to the following description of attached drawings, in which the wafer production according to the invention is shown by way of example. Components or elements of the wafer production according to the invention, which in the figures at least essentially coincide with respect to their function, may hereby be identified by the same reference symbols, these components or elements not having to be numbered or explained in all figures.

Individual or all representations of the figures described below are preferably to be regarded as construction drawings, d. H. the dimensions, proportions, functional relationships and / or arrangements resulting from the figure or figures preferably correspond exactly or preferably substantially to those of the device according to the invention or of the product according to the invention.

Show:

1a a schematic structure for creating defects in a solid body;

1b a schematic representation of a layer arrangement prior to the separation of a solid layer of a solid;

1c a schematic representation of a layer arrangement after the separation of a solid layer of a solid body;

2a a first schematically illustrated variant for defect generation by means of light waves;

2 B a second schematically illustrated variant for defect generation by means of light waves; and

3 a schematic representation of the release level,

4 a schematic representation of an additional laser treatment of the separated solid state layer according to the invention;

5 a schematic view of one according to 4 treated surface of the separated solid state layer according to the invention and

6 a schematic representation of a system according to the invention.

In 1a is a solid 2 or a substrate shown in the region of a radiation source 18 , in particular a laser, is arranged. The solid 2 preferably has a first planar surface portion 14 and a second planar area portion 16 on, wherein the first planar surface portion 14 preferably substantially or exactly parallel to the second planar area fraction 16 is aligned. The first flat area fraction 14 and the second planar area fraction 16 preferably limit the solids 2 in a Y-direction, which is preferably oriented vertically or vertically. The flat area proportions 14 and 16 preferably extend in each case in an XZ plane, wherein the XZ plane is preferably oriented horizontally. Furthermore, it can be seen from this illustration that the radiation source 18 stole 6 on the solid 2 radiates. The Rays 6 Depending on the configuration defined penetrate deep into the solid 2 and generate at the respective position or at a predetermined position a defect.

In 1b is shown a multilayer arrangement wherein the solid 2 the detachment level 8th includes and in the area of the first flat area fraction 14 with a holding layer 12 is provided, which in turn preferred by a further layer 20 is superimposed, with the further layer 20 preferably a stabilizing device, in particular a metal plate, is. At the second planar surface portion 16 of the solid 2 is preferably a polymer layer 10 arranged. The polymer layer 10 and / or the holding layer 12 are preferably at least partially, and most preferably entirely of PDMS.

In 1c is shown a state after a crack initiation and subsequent cracking. The solid state layer 4 adheres to the polymer layer 10 and is from the remainder of the solid 2 spaced or spaced.

In the 2a and 2 B are examples of the in 1a shown generation of a release plane 8th by introducing defects into a solid 2 shown by light rays.

The present invention thus relates to a method for producing solid-state layers. The method according to the invention comprises at least the steps of providing a solid 2 for separating at least one solid state layer 4 , Producing defects by means of at least one radiation source, in particular at least one laser, in particular at least one fs laser, in the internal structure of the solid to specify a Ablöseebene along which the solid state layer is separated from the solid, and the thermal impingement of a on the solid 2 arranged polymer layer 10 for, in particular mechanical, generating stresses in the solid 2 , whereby the tensions cause a crack in the solid 2 along the detachment level 8th spreads out the solid-state layer 4 from the solid 2 separates.

In 2a is thus shown schematically as defects 34 in a solid state 2 , in particular for generating a release plane 8th by means of a radiation source 18 , in particular one or more lasers, in particular one or more fs lasers, can be generated. The radiation source 18 emits radiation 6 with a first wavelength 30 and a second wavelength 32 , The wavelengths 30 . 32 are coordinated with each other or the distance between the radiation source 18 and the release level to be created 8th is tuned so that the waves 30 . 32 essentially or exactly at the release level 8th in the solid state 2 coincide, thereby at the place of the meeting 34 due to the energies of both waves 30 . 32 a defect is generated. The defect production can be achieved by different or combined decomposition mechanisms such. B. sublimation or chemical reaction, wherein the decomposition z. B. can be initiated thermally and / or photochemically.

In 2 B is a focused beam of light 6 whose focus is preferably in the release plane 8th lies. It is conceivable here that the light beam 6 is focused by one or more focusing bodies, in particular lens (s) (not shown). The solid 2 is formed in this embodiment, multi-layered and preferably has a partially transparent or transparent substrate layer 3 or material layer, which preferably consists of sapphire or has sapphire. The rays of light 6 pass through the substrate layer 3 to the detachment level 8th which prefers a sacrificial layer 5 is formed, the sacrificial layer 5 is acted upon by the radiation such that thermally and / or photochemically a partial or complete destruction of the sacrificial layer 5 is effected in the focal point or in the region of the focal point. It is also conceivable that the defects to produce the release layer 8th in the area or exactly on an interface between two layers 3 . 4 be generated. Thus, it is also conceivable that the solid state layer 4 on a carrier layer, in particular a substrate layer 3 , is generated and by means of one or more sacrificial layers 5 and / or by creating defects in an interface, especially between the solid state layer 4 and the backing layer, a release plane 8th for detaching or separating the solid-state layer 4 can be generated.

In 3 is a detachment level 8th shown the areas with different defect concentrations 82 . 84 . 86 having. It is conceivable that a plurality of areas with different defect concentrations a Ablöseebene 8th It is also conceivable that the defects 34 in the stripping level 8th are distributed substantially or exactly evenly over the surface. The different defect concentrations can be of the same size or different in size. Preferably, a first increased defect concentration provides a crack initiation concentration 82 which is preferably generated in the region of the edge or extending towards the edge or adjacent to the edge. Additionally or alternatively, a crack guidance concentration 84 be formed such that the the solid state layer 4 from the solid 2 separating crack is controllable or controllable. Furthermore, additionally or alternatively, a center concentration 86 are preferably produced, a very flat surface in the region of the center of the solid 2 allows. The crack guidance concentration is preferred 84 partially or completely formed annular or enclosing and thus preferably encloses sections and more preferably completely the center of the solid 2 or the solid state layer 4 , It is also conceivable that the crack guidance concentration 84 in one starting from the edge of the solid 2 and toward the center of the solid 2 decreases gradually or steadily or fluently. Furthermore, it is conceivable that the crack guidance concentration 84 band-like and homogeneous or substantially or exactly homogeneous.

How out 4 As can be seen, the separated solid-state layer or the wafer is exposed from above to an additional radiation treatment, wherein in particular ultra-short-time annealing by means of halogen lamps or an fs laser in the range of milliseconds or microseconds is used.

If a laser damage by means of the radiation source 18 according to 1a was carried out with a wavelength of 1,000 nm, so there is an average surface roughness (R _a ) of the separated solid state layer of usually more than 50 nm. The separated solid state layer 4 As a rule, before the additional radiation treatment, it has a matte surface which can be converted to a smoother surface and preferably a substantially reflecting surface by the ultra-short-time annealing by means of the tempering device, since the uppermost molecular layers of the separated solid layer are melted by the ultra-short heat treatment and due to the already existing uniform surface can be converted to a preferably mirror-smooth surface. Thus, the ultra-short-time annealing is applied by means of beams to this separated solid-state layer in such a way that the surface matt after the separation is changed by the ultra-short-time annealing in such a way that a preferably reflective surface results.

According to 5 is a temperature profile of a flashed solid state layer shown, which may for example be at least partially or completely made of silicon, glass or Al ₂ O ₃ .

The method according to the invention thus preferably comprises the following steps:
The present invention relates to a method for producing solid state layers. The method according to the invention preferably comprises at least the steps: providing a solid 2 for separating at least one solid state layer 4 .
Generating defects by means of radiation from at least one radiation source 18 , in particular a laser, in the internal structure of the solid for predetermining a release plane 8th , along which the solid-state layer 4 from the solid 2 is disconnected,
Separating the solid state layer 4 from the solid 2 by means of a along the release level 8th guided crack, causing the solid state 2 exposing a surface and exposing a surface to the solid state layer,
wherein after separating the solid state layer 4 by means of a tempering device, a radiation treatment for smoothing the surface structure of the exposed surface of the separated solid state layer 4 and / or the exposed surface of the solid 2 is carried out.

6 shows a plant 1 for producing solid-state layers. The attachment 1 in this case preferably comprises at least one holding device 40 for providing, in particular holding, a solid 2 , of which at least one solid-state layer 4 is separable (cf. 1 or 2 ). Furthermore, the system preferably comprises at least one radiation source 18 , in particular a laser, for generating defects by means of radiation in the internal structure of the solid 2 for specifying a detachment level 8th , along which the solid-state layer 4 from the solid 2 is separable. After treatment by the radiation source 18 becomes the treated solid 2 preferably in the direction of travel 46 a tempering device 42 for tempering, in particular cooling, one on the solid 2 generated or arranged voltage generation layer for generating voltages for separating the solid state layer 4 from the solid 2 by means of one generated by the stresses and along the release plane 8th led led crack. As a result of the crack propagation becomes on the solid 2 exposing a surface and exposing a surface to the solid state layer (not shown).

After the tempering device 42 becomes the solid 2 by means of the holding or moving device 40 at least one tempering device 44 supplied, wherein by means of the tempering device 44 a radiation treatment for smoothing the surface structure of the exposed surface of the separated solid layer 4 and / or the exposed surface of the solid 2 is feasible.

Thus, the present invention relates to a method for producing solid state layers. The method according to the invention preferably comprises at least the steps: providing a solid 2 for separating at least one solid state layer 4 , Generating defects by means of radiation from at least one radiation source 18 , in particular a laser, in the internal structure of the solid for predetermining a release plane 8th , along which the solid-state layer 4 from the solid 2 is separated, separating the solid layer 4 from the solid 2 by means of a along the release level 8th guided crack, causing the solid state 2 exposing a surface and exposing a surface to the solid state layer, wherein after separating the solid state layer 4 by means of a tempering device, a radiation treatment for smoothing the surface structure of the exposed surface of the separated solid state layer 4 and / or the exposed surface of the solid 2 is carried out.

LIST OF REFERENCE NUMBERS

1

investment

2

solid

3

substratum

4

Solid layer

5

sacrificial layer

6

radiation

8th

transfer level

10

polymer layer

12

holding layer

14

first plane area fraction

16

second plane area fraction

18

radiation source

20

stabilizing device

30

first radiation component

32

second radiation component

34

Place of defect production

40

holder

42

tempering

44

Tempering unit

46

traverse

82

Crack triggering concentration

84

Crack guidance concentration

86

center concentration

X

first direction

Y

second direction

Z

third direction

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2008/012140 [0004, 0048]
• EP 2009/067539 [0004, 0048]
• DE 19640594 A1 [0010, 0010]
• EP 000002390044 B1 [0011]
• EP 000001498215 B1 [0011]
• EP 000001494271 B1 [0011]
• EP 000001338371 B1 [0011]

Cited non-patent literature

• Ohmura et. al. (Journal of Achievements in Materials and Manufacturing Engineering, 2006, vol 17, pp. 381 ff) [0014]

Claims (13)

Method for producing solid-state layers, comprising at least the steps of: providing a solid ( 2 ) for separating at least one solid-state layer ( 4 ), Generating defects by means of radiation from at least one radiation source ( 18 ), in particular a laser, in the internal structure of the solid ( 2 ) for specifying a detachment level ( 8th ), along which the solid state layer ( 4 ) from the solid state ( 2 ), separating the solid-state layer ( 4 ) of the solid ( 2 ) by means of one along the release level ( 8th ), whereby on the solid body ( 2 ) a surface is exposed and at the solid state layer ( 4 ) a surface is exposed, wherein after the separation of the solid state layer ( 4 ) by means of a tempering device ( 44 ) a radiation treatment for smoothing the surface structure of the exposed surface of the separated solid layer ( 4 ) and / or the exposed surface of the solid ( 2 ) is carried out. A method according to claim 1, characterized in that the additional laser treatment is carried out in the form of ultra-short-time annealing, wherein the separated solid state layer is applied in the range of milliseconds and microseconds with laser beams. Method according to one of the preceding claims, characterized in that the separation of the solid state layer ( 4 ) arranging a recording layer ( 10 ) for holding the solid state layer ( 4 ) on the solid ( 2 ), and thermal loading of the recording layer ( 10 ) for, in particular mechanical, generating stresses in the solid ( 2 ), whereby due to the stresses the crack in the solid ( 2 ) along the release level ( 8th ) spreading the solid state layer ( 4 ) of the solid ( 2 ) disconnects, Method according to claim 1 or 2, characterized in that the at least one radiation source ( 18 ) for providing in the solid state ( 2 ) radiation ( 6 ) is configured such that the beams emitted by it ( 6 ) the defects at predetermined locations within the solid ( 2 ) produce. Method according to claim 3, characterized in that the radiation source ( 18 ) is set such that the beams emitted by it ( 6 ) for generating the detachment level ( 8th ) to a defined depth of less than 200 microns, preferably less than 100 microns and more preferably less than 50 microns and more preferably less than 20 microns in the solid state ( 2 ) or the radiation source is adjusted in such a way that the rays emitted by it ( 6 ) for generating the detachment level ( 8th ) to a defined depth of more than 100 .mu.m, preferably of more than 200 .mu.m and more preferably of more than 400 .mu.m and more preferably of more than 700 .mu.m in the solid state ( 2 ). Method according to one of the preceding claims 2 to 5, characterized in that the solid state ( 2 ) Silicon carbide and / or gallium arsenite and / or a ceramic material and the receiving layer of a polymer layer ( 10 ), wherein the polymer layer consist at least partially of PDMS. Method according to one of the preceding claims, characterized in that the radiation source is a femtosecond laser and / or the radiation source, in particular the laser, a pulse duration of less than 10 ps preferably less than 1 ps and more preferably of less than 500 fs and / or the Energy of the laser beam, in particular the femtosecond laser, is chosen such that the damage propagation in the solid is less than 3 times the Rayleigh length, preferably smaller than the Rayleigh length and more preferably smaller than one third of the Rayleighlänge and / or the wavelength of the laser beam, in particular of the femtosecond laser, is chosen such that the absorption of the solid is less than 10 cm ^-1 and preferably less than 1 cm ^-1 and more preferably less than 0.1 cm ^-1 and / or the individual defects in each case result from the femtosecond laser caused multi-photon excitation. Method according to one of the preceding claims, characterized in that the tempering device comprises a plurality of light sources, in particular halogen lamps, and at least one reflector for reflecting light beams, wherein the tempering device for radiation treatment of the surface structure of the exposed surface of the solid layer ( 4 ) or the exposed surface of the solid ( 2 ) to the exposed surface of the solid state layer ( 4 ) or the exposed surface of the solid ( 2 ), that between the exposed surface of the solid state layer ( 4 ) or the exposed surface of the solid ( 2 ) and the reflector, the light sources are arranged. Method according to one of the preceding claims, characterized in that the exposed surface of the solid state layer ( 4 ) or the exposed surface of the solid ( 2 ) is tempered by means of the tempering device to a temperature of more than 1000 Kelvin, in particular of more than 2000 Kelvin or of more than 3000 Kelvin. Method according to one of the preceding claims, characterized in that the heating rate of the tempering device is more than 5000 Kelvin / second, in particular more than 10,000 Kelvin / second. Method according to one of the preceding claims, characterized in that the surface structure of the exposed surface of the solid state layer ( 4 ) or the exposed surface of the solid ( 2 ) after smoothing has an average roughness (R _a ) which is less than 1/4 or less than 1/5 or less than 1/8 or less than 1/10 or less than 1/12 or less than 1/15 or less than 1/18 or less than 1/20 of the wavelength emitted by the radiation source ( 18 ) emitted radiation, in particular laser beams, is, wherein the wavelength of the radiation is less than 2.5 microns, in particular less than 2 microns or less than 1.5 microns or less than 1.2 microns, is. Wafer produced by a method according to one of claims 1 to 11. Investment ( 1 ) for producing solid-state layers, at least comprising a holding device ( 40 ) for providing, in particular holding, a solid ( 2 ), of which at least one solid-state layer ( 4 ) is separable, a radiation source ( 18 ), in particular a laser, for generating defects by means of radiation in the internal structure of the solid ( 2 ) for specifying a detachment level ( 8th ), along which the solid state layer ( 4 ) from the solid state ( 2 ) is separable, a tempering device ( 42 ) for tempering, in particular cooling, a voltage generating layer generated or arranged on the solid body for generating voltages for separating the solid state layer ( 4 ) of the solid ( 2 ) by means of a voltage generated by the stresses and along the release plane ( 8th ), whereby on the solid body ( 2 ) exposing a surface and exposing a surface to the solid-state layer, and at least one tempering device ( 44 ), wherein by means of the annealing device, a radiation treatment for smoothing the surface structure of the exposed surface of the separated solid layer ( 4 ) and / or the exposed surface of the solid ( 2 ) is feasible.

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