Abstract: A flat substrate carrier comprising a machined main surface for supporting substrates to be treated, a surface opposite to the main surface and coating on all sides. The main surface may have been machined with a view to the removal of the treated substrates from the main surface following treatment. The opposite surface has been subjected to such a machining operation or treatment that the mechanical stresses at both surfaces substantially compensate each other. The opposite surface may be machined over substantially the same area as the main surface, for example by using a material-removing operation or an EDM-operation. Both surfaces may have been subjected to the same operation. In case a treatment is carried out, which treatment may be a physical or a chemical treatment, just like the treatment by which the coating is applied, the thickness of the coating at the opposite surface may be less than the maximum thickness of the coating at the main surface.