Method for producing a layer of solid material

Abstract

A method for producing a layer of solid material includes: providing a solid body having opposing first and second surfaces, the second surface being part of the layer of solid material; generating defects by means of multiphoton excitation caused by at least one laser beam penetrating into the solid body via the second surface and acting in an inner structure of the solid body to generate a detachment plane, the detachment plane including regions with different concentrations of defects; providing a polymer layer on the solid body; and generating mechanical stress in the solid body such that a crack propagates in the solid body along the detachment plane and the layer of solid material separates from the solid body along the crack.

Claims

1. A method for producing a layer of solid material, the method comprising: providing a solid body having a first surface and a second surface opposite the first surface, the second surface being part of the layer of solid material; generating defects by means of multiphoton excitation caused by at least one laser beam penetrating into the solid body via the second surface and acting in an inner structure of the solid body to generate a detachment plane, the detachment plane comprising regions with different concentrations of defects; providing a polymer layer on the solid body; and generating mechanical stress in the solid body such that a crack propagates in the solid body along the detachment plane and the layer of solid material separates from the solid body along the crack.

2. The method of claim 1, wherein generating the mechanical stress in the solid body comprises: cooling the polymer layer such that the polymer layer contracts and/or undergoes a glass transition.

3. The method of claim 2, wherein the polymer layer is cooled at or below ambient temperature.

4. The method of claim 2, wherein the polymer layer is cooled below −10° C.

5. The method of claim 2, wherein the polymer layer is cooled below −100° C.

6. The method of claim 2, wherein the polymer layer is cooled to a temperature at which at least part of the polymer layer undergoes a glass transition.

7. The method of claim 1, wherein the polymer layer comprises polydimethylsiloxane (PDMS).

8. The method of claim 1, wherein the polymer layer holds the layer of solid material on the solid body.

9. The method of claim 1, wherein the polymer layer is disposed on the second surface of the solid body.

10. The method of claim 1, the at least one laser beam is provided by at least one radiation source such that rays irradiated by the at least one radiation source generate the defects at predetermined locations within the solid body.

11. The method of claim 10, further comprising arranging the at least one radiation source such that the rays irradiated by the at least one radiation source generate the detachment plane and penetrate into the solid body to a defined depth of less than 200 μm.

12. The method of claim 10, further comprising arranging the at least one radiation source such that the rays irradiated by the at least one radiation source generate the detachment plane and penetrate into the solid body to a defined depth of more than 100 μm.

13. The method of claim 10, wherein the at least one radiation source comprises a femtosecond laser.

14. The method of claim 13, further comprising: selecting energy of the femtosecond laser such that damage propagation within the solid body is smaller than 3 times the Rayleigh length; and/or selecting a wavelength of the femtosecond laser such that an absorption of the solid body is less than 10 cm.sup.−1.

15. The method of claim 10, wherein the at least one radiation source has a pulse duration of less than 10 ps.

16. The method of claim 1, further comprising placing the solid body on a holding layer for holding the solid body, the holding layer being disposed on the first surface of the solid body.

17. The method of claim 1, wherein the detachment plane is aligned parallel to the first surface and/or the second surface of the solid body.

18. The method of claim 1, wherein the solid body includes silicon carbide and/or gallium arsenite and/or a ceramic material and the polymer layer, and wherein the polymer layer comprises polydimethylsiloxane (PDMS).

19. The method of claim 1, wherein the stresses in the solid body are set up such that initiation and/or propagation of the crack is controlled to generate a pre-determined topography of a surface that is produced in the detachment plane.

20. The method of claim 1, wherein the solid body is a semiconductor material or a ceramic material, or the solid body comprises at least one semiconductor material or a ceramic material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The figures show as follows:

(2) FIG. 1a a diagrammatic construction for generating defects in a solid body;

(3) FIG. 1b a diagrammatic illustration of a layer arrangement before separating a layer of solid material from a solid body;

(4) FIG. 1c a diagrammatic illustration of a layer arrangement after separating a layer of solid material from a solid body;

(5) FIG. 2a a first diagrammatically illustrated variation for generating defects by means of light waves;

(6) FIG. 2b a second diagrammatically illustrated variation for generating defects by means of light waves; and

(7) FIG. 3 a diagrammatic illustration of the detachment plane.

DETAILED DESCRIPTION

(8) FIG. 1a shows a solid body 2 or a substrate that is disposed in the region of a radiation source 18, in particular a laser. The solid body 2 preferably has a first level surface portion 14 and a second level surface portion 16, the first level surface portion 14 preferably being aligned substantially or exactly parallel to the second level surface portion 16. The first level surface portion 14 and the second level surface portion 16 preferably delimit the solid body 2 in a Y direction that is preferably aligned vertically or perpendicularly. The level surface portions 14 and 16 preferably extend respectively in an X-Z plane, the X-Z plane preferably being aligned horizontally. Furthermore, it can be gathered from this illustration that the radiation source 18 irradiates rays 6 onto the solid body 2. The rays 6 penetrate by a defined depth into the solid body 2 depending on the configuration and generate a defect at the respective position or at a predetermined position.

(9) FIG. 1b shows a multi-layered arrangement, the solid body 2 containing the detachment plane 8 and being provided in the region of the first level surface portion 14 with a holding layer 12 which is in turn preferably overlaid by an additional layer 20, the additional layer 20 preferably being a stabilisation device, in particular a metal plate. A polymer layer 10 is preferably disposed on the second level surface portion 16 of the solid body 2. The polymer layer 10 and/or the holding layer 12 are preferably made at least partially and particularly preferably entirely of PDMS.

(10) FIG. 1c shows a state after a crack initiation and subsequent crack directing. The layer of solid material 4 adheres to the polymer layer 10 and is or can be spaced apart from the remaining part of the solid body 2.

(11) FIGS. 2a and 2b show examples of the generation, shown in FIG. 1a, of a detachment plane 8 by introducing defects into a solid body 2 by means of light rays.

(12) Therefore, the present disclosure relates to a method for the production of layers of solid material. The method includes at the very least the steps of providing a solid body 2 for the separation of at least one layer of solid material 4, generating defects by means of at least one radiation source, in particular at least one laser, in particular at least one fs laser, in the inner structure of the solid body in order to determine a detachment plane along which the layer of solid material is separated from the solid body, and applying heat to a polymer layer 10 disposed on the solid body 2 in order to generate, in particular mechanically, stresses in the solid body 2, due to the stresses a crack propagating in the solid body 2 along the detachment plane 8, which crack separates the layer of solid material 4 from the solid body 2.

(13) Therefore, FIG. 2a shows diagrammatically how defects 34 can be generated in a solid body 2, in particular in order to generate a detachment plane 8 by means of a radiation source 18, in particular one or more lasers, in particular one or more fs lasers. Here the radiation source 18 emits radiation 6 with a first wavelength 30 and a second wavelength 32. The wavelengths 30, 32 are matched to one another here or the distance between the radiation source 18 and the detachment plane 8 to be generated is matched such that the waves 30, 32 converge substantially or precisely on the detachment plane 8 in the solid body 2, by means of which a defect is generated at the point of coinciding 34 as a result of the energies of the two waves 30, 32. The generation of defects can take place here by means of different or combined decomposition mechanisms such as e.g. sublimation or chemical reaction, the decomposition being able to be initiated here e.g. thermally and/or photochemically.

(14) FIG. 2b shows a focused light ray 6, the focal point of which preferably lies in the detachment plane 8. It is conceivable here for the light ray 6 to be focused by one or more focusing bodies, in particular a lens/lenses (not shown). In this embodiment the solid body 2 is multi-layered in form and preferably has a partially transparent or transparent substrate layer 3 or material layer that is preferably made of sapphire or comprises sapphire. The light rays 6 pass through the substrate layer 3 onto the detachment plane 8 which is preferably formed by a sacrificial layer 5, the sacrificial layer 5 being exposed to radiation such that partial or complete destruction of the sacrificial layer 5 is brought about thermally and/or photochemically in the focal point or in the region of the focal point. It is also conceivable for the defects for the generation of the detachment layer 8 to be generated in the region of or precisely on a boundary surface between two layers 3, 4. It is therefore also conceivable for the layer of solid material 4 to be generated on a support layer, in particular a substrate layer 3, and for a detachment plane 8 for the detachment or separation of the layer of solid material 4 to be able to be generated by means of one or more sacrificial layers 5 and/or or by means of the generation of defects in a boundary surface, in particular between the layer of solid material 4 and the support layer.

(15) FIG. 3 shows a detachment plane 8 which has regions with different concentrations of defects 82, 84, 86. It is conceivable here for a plurality or regions with different concentrations of defects to form a detachment plane 8, it also being conceivable for the defects 34 in the detachment plane 8 to be distributed substantially or exactly evenly over the surface. The different concentrations of defects per area can be of the same level or of different levels. Preferably, a first increased concentration of defects constitutes 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. In addition or alternatively, a crack directing concentration 84 can be formed such that the crack separating the layer of solid material 4 from the solid body 2 can be controlled or regulated. Furthermore, in addition or alternatively, a concentration at the centre 86 is generated which preferably makes a very level surface possible in the region of the centre of the solid body 2. Preferably, the crack directing concentration 84 is made to be partially or entirely annular or encircling, and so preferably partially and particularly preferably entirely encircles the centre of the solid body 2 or the layer of solid material 4. Furthermore, it is conceivable for the crack directing concentration 84 to decrease step by step, constantly or fluently in a direction passing from the edge of the solid body 2 and towards the centre of the solid body 2. Furthermore, it is conceivable for the crack directing concentration 84 to be formed in bands and homogeneously or substantially or exactly homogeneously.

(16) Therefore, the method according to the present disclosure preferably includes the following steps:

(17) Providing a workpiece for the detachment of at least one layer of solid material and/or at least one solid body, the workpiece having at least one exposed surface, generating defects within the workpiece by means of a radiation source, in particular a laser, in particular an fs laser, or a defect generation apparatus, the defects determining a crack directing layer, applying or generating a receiving layer on the exposed surface of the workpiece such as to form a composite structure, tempering the receiving layer in order to generate stresses within the workpiece, the stresses bringing about crack propagation within the workpiece, by means of the crack propagation a layer of solid material being separated from the workpiece along the crack directing layer.

(18) Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.

LIST OF REFERENCE SIGNS

(19) 2 solid body 3 substrate 4 layer of solid material 5 sacrificial layer 6 radiation 8 detachment plane 10 polymer layer 12 holding layer 14 first level surface portion 16 second level surface portion 18 radiation source 20 stabilisation device 30 first radiation portion 32 second radiation portion 34 location of the defect generation 82 crack initiation concentration 84 crack directing concentration 86 concentration at the centre X first direction Y second direction Z third direction