Seal Ring Structure with Alignment Mark

A semiconductor structure, comprising:

• a substrate having a seal ring region and a circuit region;
• a first seal ring structure disposed in the seal ring region;
• a second seal ring structure disposed in a corner section of the seal ring region and connecting two edges of the first seal ring structure;
• a third seal ring structure disposed between the first seal ring structure and the second seal ring structure, the third seal ring structure having an L-shape;
• and
• wherein a first area between the first seal ring structure and the third seal ring structure and a second area between the second seal ring structure and the third seal ring structure are free of aluminum pads (APs).

A semiconductor structure, comprising:

• a substrate having a seal ring region and a circuit region;
• a first seal ring structure disposed in the seal ring region and surrounding the circuit region, wherein a portion of the first seal ring structure having a first L-shape forms a corner in a corner section of the seal ring region;
• a second seal ring structure disposed inside the corner section of the seal ring region, wherein the second seal ring structure has a second L-shape opposing the first L-shape;
• wherein the first seal ring structure includes a first stack of metal layers and an aluminum pad (AP) layer over the first stack of metal layers;
• wherein the second seal ring structure includes a second stack of metal layers;
• and
• wherein an area between the first seal ring structure and the second seal ring structure includes a stack of dummy metal layers and is free of an AP layer.