Chip bonding structure and manufacturing method thereof

A hybrid chip bonding method, for bonding a first substrate and a second substrate, wherein a first oxide layer is formed on a surface of the first substrate and a first copper layer is within the first oxide layer, a second oxide layer is formed on a surface of the second substrate and a second copper layer is within the second oxide layer, and the first copper layer and the second copper layer are formed through a copper damascene process, and the method comprising:

• performing a first copper chemical mechanical polishing (CMP) process on the first copper layer such that excess copper at a top surface of the first copper layer is removed to form a dishing concave;
• performing a second copper CMP process on the second copper layer such that excess copper at a top surface of the second copper layer is removed to form a dishing concave;
• removing a part of the first oxide layer to protrude the top surface of the first copper layer from the first oxide layer;
• performing a non-metal or barrier CMP process on the top surface of the first copper layer protruding from the first oxide layer to turn the top surface of the first copper layer into a convex, wherein the non-metal or barrier CMP process is a CMP process in which a polishing rate of copper is slower than that of a non-metal or barrier layer;
• connecting the dishing concave of the second copper layer to the convex of the first copper layer, and making the first oxide layer and the second oxide layer contact each other simultaneously;
• and
• performing an annealing to bond the first oxide layer and the second oxide layer via a covalent bond formed therebetween and bond the first copper layer and the second copper layer at the same time.

A thermocompression chip bonding method, for bonding a first substrate and a second substrate, wherein a first oxide layer is formed on a surface of first substrate and a first copper layer is within the first oxide layer, a second oxide layer is formed on a surface of second substrate and a second copper layer is within the second oxide layer, and the first copper layer and the second copper layer are formed through a copper damascene process, and the method comprising:

• performing a copper chemical mechanical polishing (CMP) process on the first copper layer and the second copper layer, respectively, such that excess copper at top surfaces of the first copper layer and the second copper layer are moved to form dishing concaves;
• removing a part of the first oxide layer to protrude the top surface of the first copper layer from the first oxide layer;
• removing a part of the second oxide layer to protrude the top surface of the second copper layer from the second oxide layer;
• performing a non-metal or barrier CMP process on the top surface of the first copper layer protruding from the first oxide layer and the top surface of the second copper layer protruding from the second oxide layer, respectively, so as to turn the dishing concaves of the first copper layer and the second copper layer into convexes, wherein the non-metal or barrier CMP process is a CMP process in which a polishing rate of copper is slower than that of a non-metal or barrier layer;
• and
• bonding the convexes of the first copper layer and the second copper layer.