Package structure and method for forming the same

A package structure, comprising:

• a substrate;
• a plurality of semiconductor dies formed over the substrate;
• a package layer formed over the semiconductor dies;
• a first dielectric layer formed over the package layer;
• a first alignment mark and a second alignment mark formed over the first dielectric layer, wherein the first alignment mark and the second alignment mark are made of conductive material;
• and
• a second dielectric layer formed over the first dielectric layer, wherein the second dielectric layer has an opening to expose a portion of the top surface of the second alignment mark.

A package structure, comprising:

• a substrate;
• a package layer formed over the substrate;
• a first dielectric layer formed over the package layer, wherein the first dielectric layer has at least three openings to expose a top surface of the package layer;
• a first alignment mark formed over the first dielectric layer;
• a second dielectric layer formed over the first dielectric layer;
• and
• a third dielectric layer formed over the second dielectric layer, wherein the second dielectric layer has a first trench to expose the first alignment mark, the third dielectric layer has a second trench to expose the first alignment mark, and the sidewalls of the first trench and the sidewalls of the second trench form a step-shaped structure.