providing a first substrate;

processing the first substrate by forming a via through the first substrate;

providing a second substrate, the second substrate having a thermal expansion coefficient which is substantially equal to a thermal expansion coefficient of the first substrate;

providing alignment elements on the first and second substrate for aligning the first substrate and second substrate relatively to each other;

providing a flexible structure releasably attached to the second substrate, wherein the flexible structure includes an interconnection element which is an electrically conducting element and is at least one of an optical, a mechanical and an electrical interconnection element, wherein the flexible structure is patterned to uncover the interconnection element at least in a contact region, wherein the contact region is filled with a conducting material to provide a contact element on the flexible structure, and wherein providing the flexible structure comprises providing a first flexible layer on the second substrate, providing the interconnection element on the first flexible layer, and providing a second flexible layer to cover the first flexible layer and the interconnection element, wherein at least one of the materials of the first layer and the second layer is selected from a group consisting of a BCB polymer, polyimide and liquid crystal polymer;

providing a sacrificial layer between the second substrate and the flexible structure, wherein the sacrificial layer is adapted such that the flexible structure is released from the second substrate by applying light through the second substrate to the sacrificial layer;

providing a bonding layer on at least one of the first substrate and the flexible structure, wherein the bonding layer is structured to define a first region and a second region, and wherein the bonding layer comprises a polymer having a lower glass transition temperature than each of the materials of the first substrate, the second substrate and the flexible structure;

connecting an optoelectronic element to the interconnection element of the flexible structure by means of the contact element, wherein the optoelectronic element is arranged that either light is sent through the via, light is received through the via, or both;

adjoining the first and second substrate such that the flexible structure is attached on the first substrate by means of the bonding layer; and

detaching the second substrate by degrading the sacrificial layer such that the flexible structure remains on the first substrate, wherein the second substrate is removed in the second region such that the flexible structure extends beyond the remaining first region;

wherein the flexible structure is attached on the first substrate in the first region and the flexible structure is uncoupled from the first substrate in the second region;

wherein the second substrate is selected to be transparent for the wavelength of the light applied to release the second substrate;

wherein the bonding layer and the flexible structure each comprise an aperture and wherein the first and the second substrates are adjoined such that the aperture is aligned with the via in the second substrate; and

wherein the via and the aperture are filled with a transparent filling material which gets into contact with the optoelectronic element, the filling material being filled in such a way that a surface of the first substrate opposite to the surface on which the flexible structure is arranged, and the filling material in the via together form a common plane.