A method for manufacturing a ceramic substrate by a 3D-printing process is described. The method comprises operating a 3D-printer to print a green-state ceramic body having a height extending to spaced apart first and second end surfaces and at least one via extending at least part-way along the height of the green-state ceramic body from the first end surface toward the second end surface. Then, the green-state ceramic body is sintered to provide the ceramic substrate with the at least one via. In cross-section, the at least one via has a square-shaped via with rounded corners.