A semiconductor device assembly including a substrate, a semiconductor device, a stiffener member, and mold compound. The stiffener member is tuned, or configured, to reduce and/or control the shape of warpage of the semiconductor device assembly at an elevated temperature. The stiffener member may be placed on the substrate, on the semiconductor device, and/or on the mold compound. A plurality of stiffener members may be used. The stiffener members may be positioned in a predetermined pattern on a component of the semiconductor device assembly. A stiffener member may be used so that the warpage of a first semiconductor device substantially corresponds to the warpage of a second semiconductor device at an elevated temperature. The stiffener member may be tuned by providing the member with a desired coefficient of thermal expansion (CTE). The desired CTE may be based on the individual CTEs of the components of a semiconductor device assembly.