Die edge structure for molding compound filling and the methods of forming the same

A method comprising:

• forming a wafer;
• etching a first dielectric layer of the wafer to form a first trench between two dies of the wafer, wherein a middle portion of a second dielectric layer of the wafer is directly underlying the first trench, and wherein a center middle line is in the middle of the two dies;
• and
• performing a laser grooving process to remove the middle portion of the second dielectric layer and to form a second trench, wherein the laser grooving process is performed using picosecond laser beams, and wherein in the laser grooving process, laser pulses are projected on a region between a first point farther away from the center middle line and a second point closer to the center middle line, and wherein from the first point to the second point, numbers of laser pulses increase gradually.

A method comprising:

• forming a wafer;
• grooving the wafer;
• and
• sawing the wafer to separate a device die in the wafer from other dies in the wafer, wherein the device die comprises:
• a semiconductor substrate comprising a first edge;
• a first dielectric layer over the semiconductor substrate, wherein the first dielectric layer comprises:
• a top surface;
• a second edge;
• and
• a corner surface connecting the top surface to the second edge, wherein portions of the corner surface closer to the second edge are increasingly lower than respective portions of the corner surface closer to the top surface;
• and
• a second dielectric layer over and contacting the first dielectric layer.