Electrical connecting structure having nano-twins copper and method of forming the same
Disclosed herein is a method of forming an electrical connecting structure having nano-twins copper. The method includes the steps of (i) forming a first nano-twins copper layer including a plurality of nano-twins copper grains; (ii) forming a second nano-twins copper layer including a plurality of nano-twins copper grains; and (iii) joining a surface of the first nano-twins copper layer with a surface of the second nano-twins copper layer, such that at least a portion of the first nano-twins copper grains grow into the second nano-twins copper layer, or at least a portion of the second nano-twins copper grains grow into the first nano-twins copper layer. An electrical connecting structure having nano-twins copper is provided as well.
1. A method of forming electrical connecting structure having nano-twins copper, comprising steps of:
forming a first nano-twins copper layer comprising a plurality of first nano-twins copper grains;
forming a second nano-twins copper layer comprising a plurality of second nano-twins copper grains; and
joining a surface of the first nano-twins copper layer with a surface of the second nano-twins copper layer, such that at least a portion of the first nano-twins copper grains grow into the second nano-twins copper layer, or at least a portion of the second nano-twins copper grains grow into the first nano-twins copper layer.
2. The method of claim 1 , wherein a joining interface is formed in the step of joining the surface of the first nano-twins copper layer with the surface of the second nano-twins copper layer, at least a portion of the first nano-twins copper grains growing across the joining interface, or at least a portion of the second nano-twins copper grains growing across the joining interface.
3. The method of claim 1 , wherein the first nano-twins copper grains and the second nano-twins copper grains are substantially columnar, and a width of each of the first nano-twins copper grains and the second nano-twins copper grains is less than 5 micrometers.
4. The method of claim 1 , wherein a joining interface is formed in the step of joining the surface of the first nano-twins copper layer with the surface of the second nano-twins copper layer, at least 20% by amount of the first nano-twins copper grains growing across the joining interface, or at least 20% by amount of the second nano-twins copper grains growing across the joining interface.
5. The method of claim 4 , wherein a height of each of the first nano-twins copper grains growing across the joining interface is at least 30% of a thickness of the second nano-twins copper layer; or
a height of each of the second nano-twins copper grains growing across the joining interface is at least 30% of a thickness of the first nano-twins copper layer.
6. The method of claim 1 , wherein the step of joining the surface of the first nano-twins copper layer with the surface of the second nano-twins copper layer comprises applying a pressure on at least one of the first nano-twins copper layer and the first nano-twins copper layer, such that the surface of the first nano-twins copper layer and the surface of the second nano-twins copper layer are joined under the pressure, the pressure ranging from about 0.8 Mpa to about 3 Mpa.
7. The method of claim 6 , wherein the pressure ranges from about 0.8 Mpa to about 1.5 Mpa.
8. The method of claim 1 , wherein the step of joining the surface of the first nano-twins copper layer with the surface of the second nano-twins copper layer is performed in an environment at a temperature of 200° C. to about 350° C.
9. The method of claim 1 , wherein the step of joining the surface of the first nano-twins copper layer with the surface of the second nano-twins copper layer is performed under an ambient pressure of about 10 −3 Torr to about 10 −1 Torr.
10. The method of claim 1 , wherein a joining time in the step of joining the surface of the first nano-twins copper layer with the surface of the second nano-twins copper layer ranges from about 1 minute to about 30 minutes.
11. The method of claim 1 , wherein the first nano-twins copper grains and the second nano-twins copper grains are formed and stacked in a direction of [111] crystallographic axis.
12. The method of claim 1 , wherein the surface of the first nano-twins copper layer and the surface of the second nano-twins copper layer each comprises a (111) crystal plane.