Processes for Reducing Leakage and Improving Adhesion

A method comprising:

• forming a metal post over a carrier;
• performing a first oxidation process using an oxygen-containing gas to oxidize a surface layer of the metal post, wherein a metal oxide layer is formed at surfaces of the metal post;
• placing a device die over the carrier;
• encapsulating the metal post and the device die in an encapsulant, wherein the metal oxide layer is in contact with the encapsulant;
• performing a planarization process on the encapsulant, the metal post, and the device die;
• and
• forming a redistribution structure over and electrically connecting to the metal post and the device die.

A method comprising:

• forming a metal post over a carrier;
• removing a first metal oxide layer on the metal post to reveal a metal of the metal post;
• after the first metal oxide layer is removed, oxidizing the metal post to form a second metal oxide layer on surfaces of the metal post;
• encapsulating the metal post and a device die in an encapsulant;
• planarizing the encapsulant, the metal post, and the device die until the metal post is removed, wherein a portion of the second metal oxide layer is left between the metal post and the encapsulant;
• and
• forming a redistribution structure over and electrically connecting to the metal post.