The first passivation layer 211 may be formed on the first substrate 203 over the first metallization layers 205 and the first contact pads 207. The first passivation layer 211 may be made of one or more suitable dielectric materials such as polybenzoxazole (PBO), although any suitable material, such as polyimide or a polyimide derivative, may alternatively be utilized. The first passivation layer 211 may be placed using, e.g., a spin-coating process to a thickness of between about 5 μm and about 25 μm, such as about 7 μm, although any suitable method and thickness may alternatively be used

The first external connectors 209 may be formed to provide conductive regions for contact between the first contact pads 207 and, e.g., a first redistribution layer 505 (not illustrated in FIG. 2 but illustrated and described below with respect to FIG. 5B). In an embodiment the first external connectors 209 may be conductive pillars and may be formed by initially forming a photoresist (not shown) over the first passivation layer 211 to a thickness between about 5 μm to about 20 μm, such as about 10 μm. The photoresist may be patterned to expose portions of the first passivation layers 211 through which the conductive pillars will extend. Once patterned, the photoresist may then be used as a mask to remove the desired portions of the first passivation layer 211, thereby exposing those portions of the underlying first contact pads 207 to which the first external connectors 209 will make contact.