Lead frame and manufacturing method thereof
Disclosed are a lead frame and a method for manufacturing the same. The lead frame includes a copper substrate and a rough copper layer having surface roughness of 110 nm to 300 nm on a surface of the copper substrate.
1. A lead frame comprising:
a copper substrate, wherein the copper substrate includes nickel (Ni), magnesium (Mg), and silicon (Si);
a rough copper layer having surface roughness of 110 nm to 300 nm and formed over a surface of the copper substrate; and
a metal layer with a rough upper surface formed over the rough copper layer, wherein the rough upper surface of the metal layer has a rough surface profile different from that of the rouge copper layer.
2. The lead frame of claim 1 , further comprising a silver plating layer locally formed over the rough copper layer.
3. The lead frame of claim 1 , wherein the rough copper layer has a thickness of 0.3 μm to 0.6 μm.
4. The lead frame of claim 1 , wherein the metal layer with a rough upper surface is formed of nickel (Ni), palladium (Pd), or gold (Au).
5. A lead frame comprising:
a copper substrate, wherein the copper substrate includes nickel (Ni), magnesium (Mg), and silicon (Si);
a rough copper layer over the copper substrate;
a Ni layer over the rough copper layer;
a Pd layer over the Ni layer; and
an Au layer over the Pd layer;
wherein the Ni layer, Pd layer, and Au layer each has a rough upper surface with a rough surface profile different from that of the rough copper layer.
6. The lead frame of claim 5 , wherein the Au layer has surface roughness of 90 nm to 270 nm.
7. The lead frame of claim 5 , wherein the Ni layer is thicker than the Pd layer, and the Pd layer is thicker than the Au layer.
8. A method for manufacturing a lead frame, the method comprising:
preparing a copper substrate, wherein the copper substrate includes nickel (Ni), magnesium (Mg), and silicon (Si);
forming a rough copper layer by electrically plating the copper substrate in a copper sulfate pentahydrate solution; and
forming a metal layer with a rough upper surface over the rough copper layer, wherein the rough upper surface of the metal layer has a rough surface profile different from that of the rough copper layer.
9. The method of claim 8 , wherein the rough copper layer is formed by using the copper sulfate pentahydrate solution containing copper ions having density of 5 g/L to 70 g/L at current density of 3ASD to 7ASD for time of 10 seconds to 40 seconds.
10. The method of claim 8 , wherein the rough copper layer has surface roughness of 110 nm to 300 nm.
11. The method of claim 8 , wherein the rough copper layer has a thickness of 0.3 μm to 0.6 μm.
12. The method of claim 8 , further comprising locally forming a silver plating layer on the rough copper layer.
13. The method of claim 8 , wherein the metal layer with a rough upper surface is formed of Ni, Pd, or Au.
14. The method of claim 13 , wherein the Au layer has surface roughness of 90 nm to 270 nm.