A semiconductor package including a leadframe having first and second major surfaces and a mold lock opening extending between the first and second major surfaces. The semiconductor package includes a semiconductor die coupled to the first major surface, and an encapsulating material formed about the semiconductor chip and a portion of the first major surface of the leadframe and filling all but a portion of the mold lock opening, the unfilled portion of the mold lock opening forming a vent extending from the second major surface to the first major surface, the vent providing a pathway for air to escape from between the second major surface and a surface to which the second major surface is to be attached.