Method for Separating Solid Body Layers from Composite Structures Made of SiC and a Metallic Coating or Electrical Components

A method for producing microcracks in an interior of a composite structure, the method comprising:

• providing the composite structure, the composite structure having a solid body and at least one metallic coating and/or electrical components situated or provided on one side of the solid body, an opposing side of the solid body forming a flat surface, the solid body containing or being made of silicon carbide;
• and
• producing modifications in the interior of the solid body,
• wherein laser radiation is introduced into the solid body via the flat surface,
• wherein the laser radiation causes multiphoton excitation,
• wherein the multiphoton excitation brings about plasma generation,
• wherein the modifications are effected by the plasma in the form of a material transformation,
• wherein the material transformation generates compressive stresses in the solid body,
• wherein the solid body develops subcritical cracks in a surrounding area of a particular modification,
• wherein the modifications are produced at a distance of less than 150 μm from the metallic coating and/or the electrical components,
• wherein the laser radiation is introduced into the solid body in pulses,
• wherein each pulse introduces an energy E into the solid body,
• wherein as a result of the plasma generation and/or microcracks already produced, 20% maximum of the energy E of the particular pulse is transmitted through the solid body up to the metallic coating and/or the electrical components.