1. A welding method for joining a first piece and a second piece, the method comprising:
providing a recess on an edge of the first piece, the edge of the first piece configured to cooperate with the second piece;
positioning the first piece relative to the second piece so as to provide a gap between the first piece and the second piece; and
providing a tack weld within the recess of the first piece, wherein the recess is configured to accommodate placing the tack weld at a root of the gap.
2. The method of claim 1, wherein a plurality of recesses are provided at a pre-determined location on the edge of the first piece.
3. The method of claim 1, wherein the recess is configured to have an arcuate shape.
4. The method of claim 1, wherein the gap between the first piece and the second piece is configured to define at least one of the group consisting of a narrow J-shaped groove, a single bevel joint, and a flare joint.
5. The method of claim 1 wherein providing the tack weld further includes:
filling at least a portion of the recess of the first piece with weld material;
placing a backing material in the grooved joint and in contact with the weld material, the backing material configured to form a straight edge on the tack weld; and
filling a remaining portion of the recess of the first mating surface with additional weld material.
6. The method of claim 5, wherein the backing material is made of a ceramic.
7. The method of claim 1, wherein the tack weld is provided using gas metal arc welding.
8. The method of claim 1 further including joining the first piece and the second piece using a hybrid laser arc welding method.
9. The method of claim 8, wherein the hybrid laser arc welding method includes positioning a gas metal arc welding torch substantially perpendicular with respect to a welding direction and positioning a laser beam oblique with respect to the welding direction during the hybrid laser arc welding method.
10. The method of claim 8, wherein the hybrid laser arc welding method includes positioning a gas metal arc welding torch oblique with respect to a welding direction and a laser beam is substantially perpendicular with respect to the welding direction during the hybrid laser arc welding method.
11. A welding method for joining a first piece and a second piece, the method comprising:
providing a recess on an edge of the first piece, the edge of the first piece configured to cooperate with the second piece;
positioning the first piece relative to the second piece so as to provide a gap configured to define a narrow J-groove between the first piece and the second piece; and
providing a tack weld within the recess of the first piece, wherein the recess is configured to accommodate placing the tack weld at a root of the narrow J- groove.
12. The method of claim 11, wherein a plurality of recesses are provided at pre-determined locations on the edge of the first piece.
13. The method of claim 12, wherein the recess is configured to have an arcuate shape.
14. The method of claim 11 wherein providing the tack weld further includes:
filling at least a portion of the recess of the first piece with weld material;
placing a backing material in the narrow J-groove and in contact with the weld material, the backing material configured to form a straight edge on the tack weld; and
filling a remaining portion of the recess of the first piece with the additional weld material.
15. The method of claim 14, wherein the backing material is made of a ceramic.
16. The method of claim 11, wherein the tack weld is provided using gas metal arc welding.
17. The method of claim 11 further including joining the first piece and the second piece using a hybrid laser arc welding method.
18. The method of claim 17, wherein a gas metal arc welding torch is substantially perpendicular with respect to a welding direction and a laser beam is oblique with respect to the welding direction during the hybrid laser arc welding method.
19. The method of claim 17, wherein a gas metal arc welding torch is oblique with respect to a welding direction and a laser beam is substantially perpendicular with respect to the welding direction during the hybrid laser arc welding method.
20. A welding method for joining a first piece and a second piece, the method comprising:
providing at least one recess on an edge of the first piece, the edge of the first piece configured to cooperate with the second piece;
positioning the first piece relative to the second piece so as to provide a gap between the first piece and the second piece;
providing a tack weld within the at least one recess of the first piece by filling at least a portion of the at least one recess with weld material, wherein the at least one recess is configured to accommodate placing the weld material at a root of the gap; and
joining the first piece and the second piece by forming a seam using a hybrid laser arc welding method, wherein the hybrid laser arc welding method includes directing a laser beam at the root of the gap and depositing weld material within the gap with a gas metal arc welding torch.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A semiconductor device comprising:
an insulating film (10);
an interlayer dielectric film (12) on the insulating film;
a trench (11) within the dielectric film;
a first etching stopper layer (16) covering the dielectric film; and
an interconnection, comprising,
a metal layer (39) filling the trench,
a barrier metal layer (13) coating a bottom and sides of the trench, the barrier metal layer located intermediate the metal layer and the dielectric film with the barrier metal layer separating the metal layer from the dielectric film,
particles of metal (15) on a lower horizontal surface of the barrier metal layer, and
carbon nanotubes (14) formed on the metal particles and mixed in the metal layer,
wherein, each of i) the trench (11), ii) the interconnection, iii) the metal layer (39), iv) the barrier metal layer (13), and the carbon nanotubes (14) extend through the first etching stopper layer.
2. The semiconductor device according to claim 1, further comprising:
a second etching stopper layer (27) formed on the etching stopper layer (16), on the barrier metal layer (13), and on part of the metal layer (39);
another interlayer dielectric film (29) formed on the second etching stopper layer;
a third etching stopper layer (30) formed on the another dielectric film;
a via hole formed in the second etching stopper layer, the another dielectric film, and the third etching stopper layer;
metal (26) filling the via hole;
another barrier metal layer (28) covering a bottom and sides of the via hole and extending up to a top of the another dielectric film, the another barrier metal layer separating the metal filling the via hole from the bottom and sides of the via hole;
further metal particles on the another barrier metal layer covering the bottom of the via hole;
further carbon nanotubes (24) formed on further the metal particles and mixed in the metal filling the via hole,
wherein, said metal filling the via hole, said further carbon nanotubes, and said another barrier metal layer define a connection plug contacting said interconnection.
3. The semiconductor device according to claim 1, wherein the carbon nanotubes are oriented substantially perpendicularly to the lower horizontal surface of the barrier metal layer.
4. The semiconductor device according to claim 1, wherein the carbon nanotubes are provided in the whole trench.
5. The semiconductor device according to claim 1, wherein the metal layer is formed by a plating liquid comprising the carbon nanotubes.