Structured substrate, method for manufacturing the structured substrate, and use of the structured substrate

A structured substrate, comprising:

• a planar substrate having two opposing planar surfaces;
• at least one through-hole extending through a material of the planar substrate forming an inner wall surface surrounding the at least one through-hole and connecting the two opposing planar surfaces;
• and
• a coating covering at least some areas of the inner wall surface of the at least one through-hole, wherein the coating is light absorbing and/or light reflecting, wherein one or both of the two opposing planar surfaces are free of the coating;
• wherein the inner wall surface has an arithmetic average roughness between 0.1 μm and 2 μm and/or the coating has an arithmetic average roughness between 0.05 μm and 2 μm.

A method for manufacturing a structured substrate, comprising:

• providing a planar substrate having two opposing planar surfaces, wherein at least one through-hole extends through a material of the planar substrate so as to form an inner wall surface surrounding the at least one through-hole and connecting the two opposing planar surfaces;
• depositing a coating, which is light absorbing and/or light reflecting, onto the planar substrate covering at least some areas of the inner wall surface of the at least one through-hole, wherein the inner wall surface has an arithmetic average roughness between 0.1 μm and 2 μm and/or the coating has an arithmetic average roughness between 0.05 μm and 2 μm;
• and
• treating one or both of the two opposing planar surfaces of the planar substrate to remove coating so that one or both of the two opposing planar surfaces are free of the coating.

An assembly, comprising:

• a layer structure of two or more layers, wherein at least one of the layers is a structured substrate comprising:
• a planar substrate having two opposing planar surfaces;
• at least one through-hole extending through a material of the planar substrate forming an inner wall surface surrounding the at least one through-hole and connecting the two opposing planar surfaces;
• and
• a coating covering at least some areas of the inner wall surface of the at least one through-hole, wherein the coating is light absorbing and/or light reflecting, wherein one or both of the two opposing planar surfaces are free of the coating;
• wherein the inner wall surface has an arithmetic average roughness between 0.1 μm and 2 μm and/or the coating has an arithmetic average roughness between 0.05 μm and 2 μm.