Forming large chips through stitching

A method comprising:

• forming a dielectric layer over a substrate;
• performing a first light-exposure process on a first portion of a photo resist;
• performing a second light-exposure process on a second portion of the photo resist;
• developing the photo resist to remove the first portion and the second portion of the photo resist, wherein a trench ring is formed in the photo resist;
• etching the dielectric layer using the photo resist as an etching mask to extend the trench ring into the dielectric layer;
• and
• filling the trench ring with a conductive material to form a seal ring.

A method comprising:

• forming a wafer comprising:
• forming a dielectric layer over a semiconductor substrate;
• forming a seal ring in the dielectric layer, wherein the seal ring comprises:
• a first portion having a first width;
• a second portion having a second width;
• and
• a third portion joining the first portion to the second portion, wherein the third portion has a third width greater than the first width and the second width;
• and
• sawing the wafer to form a package comprising the seal ring therein, wherein an edge of the package is parallel to the first portion, the second portion, and the third portion of the seal ring.