1. A method for forming a binal-layer bump on a substrate, comprising:
depositing a first metal powder on the substrate;
placing a first masking plate over the substrate, the first masking plate having at least one aperture;
melting the first metal powder to form a first bump;
depositing a second metal powder over at least the first bump; placing a second masking plate over the substrate, the second masking plate having at least one aperture; and
melting the second metal powder to form a second bump on the first bump, wherein the first bump and the second bump form the binal-layer bump and wherein the binal-layer bump is surrounded by remaining portions of the first and second metal powders.
2. The method for forming a binal-layer bump according to claim 1, wherein melting the first metal powder further comprises:
melting a selected portion of the first metal powder by irradiating the selected portion through the at least one aperture.
3. The method for forming a binal-layer bump according to claim 2, wherein melting the second metal powder further comprises:
melting a selected portion of the second metal powder by irradiating the selected portion through the aperture of the second masking plate.
4. The method for forming a binal-layer bump according to claim 1, wherein a melting point of the second metal powder is lower than a melting point of the first metal powder.
5. The method for forming a binal-layer bump according to claim 1, wherein the first metal powder and the second metal powder each have a particle size between about 5 microns to about 10 microns.
6. The method for forming a binal-layer bump according to claim 5, wherein the first metal powder comprises one of copper and high lead solder and the second metal powder comprises a eutectic solder.
7. The method for forming a binal-layer bump according to claim 1, further comprising cleaning a bond pad on the substrate before depositing the first metal powder.
8. The method for forming a binal-layer bump according to claim 7, wherein the cleaning step comprises irradiating the bond pad to burn out any contaminants thereon.
9. The method for forming a binal-layer bump according to claim 1, wherein melting the first metal powder further comprises irradiating a portion of the first metal powder with a programmable single laser beam.
10. The method for forming a binal-layer bump according to claim 1, further comprising removing any unmelted portions of the first and second metal powders remaining on the substrate.
11. A method for forming a multi-layer connector on a substrate, comprising:
depositing a first metal powder on the substrate;
placing a first masking plate over the substrate, the first masking plate having at least one aperture;
irradiating a selected portion of the first metal powder to form a first bump;
depositing a second metal powder over the first bump; placing a second masking plate over the substrate, the second masking plate having at least one aperture; and
irradiating the second metal powder to form a second bump on the first bump, wherein the first bump and the second bump form the multi-layer connector and wherein the binal-layer bump is surrounded by remaining portions of the first and second metal powders.
12. The method forming a multi-layer connector according to claim 11, wherein a melting point of the second metal powder is lower than a melting point of the first metal powder.
13. The method forming a multi-layer connector according to claim 11, wherein the first metal powder and the second metal powder each have a particle size between about 5 microns to about 10 microns.
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 weld metal, consisting essentially of:
C in a content by mass of from 0.05 to 0.20%,
Si in a content by mass of from 0.10 to 0.50%,
Mn in a content by mass of from 0.60 to 1.3%,
Cr in a content by mass of from 1.8 to 3.0%,
Mo in a content by mass of from 0.8 to 1.5%,
V in a content by mass of from 0.25 to 0.50%,
Nb in a content by mass of from 0.010 to 0.050%,
N in a content by mass of greater than 0% and no more than 0.025%,
O in a content by mass of from 0.020 to 0.060%,
iron, and
inevitable impurities,
wherein a value A defined by formula (I) is 200 or greater, the formula expressed as follow:
Value A=(V51+Nb93){V\xd7(Cr5+Mo2)}\xd7104\u2003\u2003(1),
wherein V, Nb, Cr, and Mo respectively indicate contents of V, Nb, Cr, and Mo by mass % in the weld metal,
carbide particles each having an equivalent-circle diameter of 0.40 \u03bcm or more contained in the weld metal have an average equivalent-circle diameter of less than 0.85 \u03bcm, and
in segments connecting centers of three or more carbide particles which are present on a 6-\u03bcm straight line and each of which has an equivalent-circle diameter of 0.4 \u03bcm or more, a sum of lengths of portions where the segments intersect the carbide particles is 25% or more of an overall length of the segments.
2. A weld structure, comprising the weld metal according to claim 1.
3. The weld metal according to claim 1, wherein the value A is 250 or less.
4. The weld metal according to claim 1, wherein the carbide particles each having the equivalent-circle diameter of 0.40 \u03bcm or more contained in the weld metal have an average equivalent-circle diameter of less than 0.7 \u03bcm.
5. The weld metal according to claim 1, wherein in segments connecting centers of three or more carbide particles which are present on the 6-\u03bcm straight line and each of which has the equivalent-circle diameter of 0.4 \u03bcm or more, a sum of lengths of portions where the segments intersect the carbide particles is 40% or more of the overall length of the segments.