An electromagnetic shield is provided, for example for a printed circuit board. A shield lid fits onto a base structure having at least two, more typically four, opposing sidewalls. The lid includes a top portion and a lip extending downward from the top portion to cap the base structure. The lid includes at least one deformation inhibiting feature extending downward from the top portion, for placement near or against an interior portion of a sidewall, for example against an edge of a folded-over sidewall. The deformation inhibiting feature may include one or more half-dimples stamped into the lid. In response to an external force, the deformation inhibiting feature presses against its adjacent sidewall in order to brace the shield lid. This inhibits the base structure from deforming the lip due to outward pressure of a sidewall onto a portion of the lip, located opposite the deformation inhibiting feature.