Semiconductor package substrate with a smooth groove about a perimeter of a semiconductor die
A semiconductor package includes a metallic pad and leads spaced from the metallic pad by a gap, the metallic pad including a roughened surface. The semiconductor package further includes a semiconductor die including bond pads, and an adhesive between the roughened surface of the metallic pad and the semiconductor die, therein bonding the semiconductor die to the metallic pad, wherein the adhesive includes a resin. The metallic pad further includes a groove surrounding the semiconductor die on the roughened surface, the groove having a surface roughness less than a surface roughness of the roughened surface of the metallic pad.
1. A method for fabricating a semiconductor package comprising:
applying an adhesive including a resin to a roughened surface of a metallic pad inside of a perimeter formed by a groove on the roughened surface, the groove having a surface roughness less than a surface roughness of the roughened surface,
wherein the semiconductor package further includes leads spaced from the metallic pad by a gap;
positioning a semiconductor die including bond pads on the metallic pad in contact with the adhesive such that the groove surrounds the semiconductor die on the roughened surface; and
curing the adhesive to bond the semiconductor die to the metallic pad.
2. The method of claim 1 , further comprising stamping the roughened surface of the metallic pad to form the groove.
3. The method of claim 1 , wherein positioning the semiconductor die on the metallic pad includes identifying a location of the groove with an imaging system to locate the semiconductor die on the metallic pad such that the groove surrounds the semiconductor die.
4. The method of claim 1 , wherein applying the adhesive includes identifying a location of the groove with an imaging system to locate the adhesive inside the perimeter of the groove.
5. The method of claim 1 ,
wherein the resin bleeds from the adhesive while curing the adhesive to bond the semiconductor die to the metallic pad, and
wherein the groove prevents the resin from bleeding onto the roughened surface of the metallic pad outside the groove.
6. The method of claim 1 , further comprising forming wire bonds between the bond pads of the semiconductor die and the leads.
7. The method of claim 6 , further comprising covering the semiconductor die, the adhesive, the roughened surface of the metallic pad, and the wire bonds with mold compound, and at least partially covering the leads with the mold compound.
8. The method of claim 1 , wherein the metallic pad includes a planar base metal and layer of nickel plated on the base metal to form the roughened surface.
9. The method of claim 1 , wherein the groove forms a rectangular shape surrounding the semiconductor die on the roughened surface.
10. The method of claim 1 , wherein all surfaces of the metallic pad are roughened except for the groove.
11. The method of claim 1 , wherein a surface roughness of the groove is less than 0.5 micrometers (μm).
12. The method of claim 1 , wherein a surface roughness of the metallic pad is at least 1.0 micrometers (μm).
13. The method of claim 1 , wherein a side of the metallic pad including the roughened surface includes one or more of a group consisting of:
a metal oxide layer;
a micro-crystalline metal layer; and
a rough nickel layer.