Method for producing a composite material (5), in particular for a circuit board, wherein the composite material (5) comprises a planar base material (1), in particular a ceramic, to which an additional layer (2), in particular a metallisation, is applied on one side or both sides by means of a solder layer (3), characterised by: - providing the base material (1), wherein the base material (1) has a first surface (A1) on at least one side; - providing the additional layer (2) and arranging the solder layer (3) between a second surface (A2) of the additional layer (2) and the first surface (A1) in such a way that when the additional layer (3) is deposited on the first surface (A1), the first surface (A1) of the base material (1) is covered by the solder layer (3) in a planar manner; wherein a thickness of the solder layer (3) between the base material (1) and the additional layer (2) is smaller than 12 µm, in particular smaller than 7 µm; - heating the base material (1) and the additional layer (2) arranged on the first surface (A1) to at least partially melt the solder layer (3) and connecting the base material (1) to the at least one additional layer (2).