In a first aspect, the present disclosure relates to a method for designing a pattern of a stress relief layer for a flat device to be transformed into a shape-retaining non-flat device by deformation of the flat device. The flat device (and thus also the non-flat device) may comprise at least two components and at least one electrical interconnection between two components. In a second aspect, the present disclosure is related to a method of manufacturing a shape-retaining non-flat device by deformation of a flat device, wherein the flat device is attached to a patterned stress relief layer designed in accordance with the first aspect of the present disclosure. In preferred embodiments, the stress relief layer is a thermoplastic layer or a layer comprising a thermoplastic material and deformation of the flat device comprises deformation by a thermoforming process, after attachment of the flat device to the stress relief layer.