A method for manufacturing includes applying patterned electromagnetic energy to each of a sequence of layers of a dry film comprising a photosensitive material so as to create in the photosensitive material in each of the layers a respective two-dimensional (2D) pattern corresponding to a slice of a predefined three-dimensional (3D) structure. The layers in the sequence in which the respective 2D pattern has been created are laminated together to produce a multi-layer stack. The multi-layer stack is developed so as to remove the photosensitive material in which the 2D pattern has not been created, thereby forming the 3D structure.