A method for forming bonded substrates includes providing a plurality of substrates, each of which having a top surface. A characteristic length for each of the plurality of substrates is determined by: determining a topographical profile of the top surface of the substrate from an interior portion to an edge portion along a radial direction, determining a highest point of the profile, and defining the characteristic length as a distance from the highest point to the edge portion. A first substrate and a second substrate are selected where at least one of the first or the second substrates has a characteristic length shorter than a predetermined length. The first substrate and the second substrate are brought into contact and form bonded substrates, with the top surface of the first substrate facing the top surface of the second substrate.