Splitting of a solid using conversion of material

Patent metadata

Field	Value
Publication number	US-2018290232-A1
Application number	US-201816003221-A
Country	US
Kind code	A1
Filing date	Jun 8, 2018
Priority date	Jan 15, 2014
Publication date	Oct 11, 2018
Grant date	—

Abstract

The invention relates to a method for creating a detachment zone in a solid in order to detach a solid portion, especially a solid layer, from the solid, said solid portion that is to be detached being thinner than the solid from which the solid portion has been removed. According to the invention, the method comprises at least the steps of: providing a solid which is to be processed and which is preferably made of a chemical compound; providing a LASER light source; subjecting the solid to LASER radiation from the LASER light source so that the laser beams penetrate into the solid via a surface of the solid portion that is to be cut off; the LASER radiation is applied in a defined manner to a predefined portion of the solid inside the solid such that a detachment zone or a plurality of partial detachment zones is formed; the method is characterized in that a number of modifications is successively created in the crystal lattice by the applied laser radiation, and the crystal lattice fissures at least partially in the regions surrounding the modifications as a result of the modification, said fissures in the region of the modifications predefining the detachment zone or a plurality of partial detachment zones.

First claim

1 . A method for separating at least one solid portion from a solid, wherein the method comprises at least the steps:
modifying the crystal lattice of the solid by means of a laser, wherein a plurality of modifications are produced in the crystal lattice, wherein the crystal lattice fissures as a result of the modifications in the regions surrounding the modifications at least in respectively one portion, wherein a detachment zone is predefined by the fissures in the region of the modifications, wherein the laser beam penetrates via a polished surface into the at least partially transparent solid, wherein the fissures are subcritical and propagate less than 5 mm in the solid, wherein the subcritical fissures propagate for the most part in a plane parallel to the surface of the solid through which the laser radiation penetrates into the solid, wherein the solid comprises or consists of silicon carbide, wherein the solid is an ingot, and wherein the solid is separated into at least two components along the detachment zone.

2 . The method according to claim 1 , characterized in that the fissures are extending substantially in the horizontal direction.

3 . The method according to claim 1 , characterized in that the fissures can run in sections on different planes.

4 . The method according to claim 1 , characterized in that the orientation of the ingot is used to adapt the modifications produced by means of the laser beams to the crystallographic orientation.

5 . The method according to claim 1 , characterized in that the subcritical fissures propagate in a defined manner in a layer in such a manner that the detachment zone has a defined shape.

6 . The method according to claim 1 , characterized in that the crystal lattice fissures at least for the most part in a portion spaced apart from the centre Z of the respective modification.

7 . The method according to claim 1 , characterized in that the detachment zone is located in the lengths direction of the solid on one side of the modifications, wherein the polished surface is arranged on the other side of the modifications.

8 . The method according to claim 1 , characterized in that the modifications are completely removed from the residual solid due to the separation of the solid layer.

9 . The method according to claim 8 , characterized in that the residual solid shows no residue of these modifications after the separation of the solid layer.

10 . The method according to claim 1 , characterized in that the wavelength of the laser beam of the laser is selected in such a manner that the linear absorption of the solid is less than 0.1 cm −1 .

11 . The method according to claim 1 , characterized in that the energy of the laser beams of the laser is selected in such a manner that the modification in the solid in at least one direction is less than three times the Rayleigh length.

12 . The method according to claim 1 , characterized in that a pulse repetition frequency of the laser between 16 kHz and 20 MHz is provided.

13 . The method according to claim 1 , characterized in that the laser radiation is introduced into the solid with a pulse density between 100 nJ/μm 2 and 10 000 nJ/μm 2 .

14 . The method according to claim 1 , characterized in that the laser beam is split by a diffractive optical element into a plurality of laser beams in order to produce a corresponding number of modifications according to the splitting of the laser beam.

15 . The method according to claim 1 , characterized in that the focus is less than 1000 μm away from a penetration surface of the solid, wherein at least individual light beam components penetrate into the solid via the penetration surface to produce the physical modification.

16 . The method according to claim 1 , characterized in that the focus and/or the amount of energy and/or the application time is set differently additionally or alternatively to the location of the modifications.

17 . The method according to claim 1 , characterized in that the control unit controls the generation of modifications depending on the material properties of the solid.

18 . The method according to claim 1 , characterized in that the optical system for focusing the laser beam has a numerical aperture of 0.1 to 0.9.

19 . The method according to claim 1 , characterized in that the modifications have a vertical extension of less than 50 μm.

20 . The method according to claim 1 , characterized in that a picosecond laser is used, wherein the laser has a wavelength between 800 nm and 1200 nm.

21 . The method according to claim 1 , characterized in that the laser beam causes a material conversion, wherein amorphous phases result from that material conversion.

Assignees

• Siltectra Gmbh

Inventors

• Richter Jan
• Beyer Christian
• Rieske Ralf

Classifications

• H10P90/126

  by chemical etching · CPC title

• H10P54/00

  Cutting or separating of wafers, substrates or parts of devices · CPC title

• H10P52/00

  Grinding, lapping or polishing of wafers, substrates or parts of devices · CPC title

• B23K2103/56

  being semiconducting · CPC title

• B23K2103/50

  Inorganic materials other than metals or composite materials · CPC title