Method for manufacturing semiconductor device with metallization structure
A method for manufacturing a semiconductor device includes: providing a semiconductor substrate having first and second sides; forming at least one doping region at the first side; forming a first metallization structure at the first side on and in contact with the at least one doping region; and subsequently forming a second metallization structure at the second side, the second metallization structure forming at least one silicide interface region with the semiconductor substrate and at least one non-silicide interface region with the semiconductor substrate.
1. A method for manufacturing a semiconductor device, the method comprising:
providing a semiconductor substrate comprising a first side and a second side;
forming a first metal layer on and in contact with the second side of the semiconductor substrate;
forming a mask on the first metal layer, the mask comprising openings exposing portions of the first metal layer;
etching the first metal layer using the mask as an etching mask to remove the exposed portions of the first metal layer from the second side of the semiconductor substrate and to form first metallization regions which remain on the second side of the semiconductor substrate;
heating the first metallization regions and the second side of the semiconductor substrate to form silicide interface regions between the first metallization regions and the semiconductor substrate, the second side of the semiconductor substrate being heated to a higher temperature than the first side of the semiconductor substrate; and
forming a second metal layer on and in contact with the second side of the semiconductor substrate, the second metal layer completely covering the first metallization regions and forming one or more non-silicide interface regions with the semiconductor substrate.
2. The method of claim 1 , wherein the first metallization regions transform only partly into a silicide to form the silicide interface regions.
3. The method of claim 1 , wherein:
the first metal layer is a molybdenum nitride layer; and
the second metal layer is a copper layer or a layer of a copper alloy.
4. The method of claim 1 , further comprising, prior to forming the first metal layer:
forming at least one doping region at the first side of the semiconductor substrate;
forming a first metallization structure at the first side of the semiconductor substrate and on and in contact with the at least one doping region.
5. The method of claim 1 , further comprising:
forming a passivation structure at the first side of the semiconductor substrate, the passivation structure covering lateral edges of the first metallization structure and comprising at least one opening to expose a central part of the first metallization structure.
6. The method of claim 1 , wherein heating the first metallization regions and the second side of the semiconductor substrate comprises:
directing at least one laser beam on the first metallization regions and the second side of the semiconductor substrate.
7. The method of claim 6 , wherein the second side of the semiconductor substrate is heated to a temperature above 1000° C. by the at least one laser beam.
8. The method of claim 6 , further comprising:
limiting the heating of the second side of the semiconductor substrate by the at least one laser beam to below a melting point of the first metallization regions.
9. The method of claim 8 , wherein limiting the heating of the second side of the semiconductor substrate comprises:
scanning the at least one laser beam over the second side of the semiconductor substrate with a scan rate that keeps the heating of the second side of the semiconductor substrate below the melting point of the first metallization regions.
10. The method of claim 1 , further comprising:
implanting n-type dopants into the second side of the semiconductor substrate after formation of the first metallization regions.