In an embodiment, a device includes: a back-side redistribution structure including: a metallization pattern on a first dielectric layer; and a second dielectric layer on the metallization pattern; a through via extending through the first dielectric layer to contact the metallization pattern; an integrated circuit die adjacent the through via on the first dielectric layer; a molding compound on the first dielectric layer, the molding compound encapsulating the through via and the integrated circuit die; a conductive connector extending through the second dielectric layer to contact the metallization pattern, the conductive connector being electrically connected to the through via; and an intermetallic compound at the interface of the conductive connector and the metallization pattern, the intermetallic compound extending only partially into the metallization pattern.