Method for filling gap

A method for filling a gap, comprising:

• filling a dielectric layer in the gap by atomic layer deposition, so that a seam is formed in the dielectric layer, the dielectric layer including two surface portions at two opposite sides of the seam, respectively;
• introducing a surface modification agent into the seam such that each of the two surface portions has first functional groups and second functional groups;
• forming a stress layer on the dielectric layer to cover the seam, the stress layer including a material different from that of the dielectric layer;
• and
• applying an energy field to permit the two surface portions to bond with each other through reaction between the first functional groups and the second functional groups.

A method for filling a gap, comprising:

• filling a dielectric layer in the gap by atomic layer deposition, so that a seam is formed in the dielectric layer, the dielectric layer including two surface portions at two opposite sides of the seam, respectively;
• introducing a surface modification agent into the seam such that each of the two surface portions has first functional groups and second functional groups;
• and
• applying an energy field to permit the two surface portions to bond with each other through reaction between the first functional groups and the second functional groups.