Methods and devices for manufacturing cantilever leads in a semiconductor package
A method of manufacturing a semiconductor package includes providing a metallic leadframe having a plurality of cantilever leads and a mounting area for mounting a die, and disposing one or more non-conductive supports adjacent to a recessed surface of the cantilever leads to support the leads during die mount, wire bond, and encapsulation processes. The method further includes mounting the die in the mounting area and electrically connecting the die to the cantilever leads, and then encapsulating at least a portion of the die, the leadframe, and the supports with an encapsulant.
1. A method of manufacturing a semiconductor package which contains a semiconductor die and a metallic leadframe, comprising:
providing the leadframe having a mounting area for mounting the die and a plurality of cantilever leads with a first end oriented away from the mounting area and a second end oriented toward the mounting area, wherein the cantilever leads each has a first thickness at the first end and a second thickness at the second end to form a recessed surface at the second end, the first thickness being greater than the second thickness;
disposing one or more non-conductive supports adjacent to the recessed surface of the cantilever leads to support the cantilever leads;
electrically connecting a plurality of bond pads of the die to the cantilever leads at the second end, wherein the die is mounted in the mounting area; and
encapsulating at least a portion of the die, the leadframe, and the supports with an encapsulant.
2. The method of claim 1 , wherein disposing one or more non-conductive supports adjacent to the recessed surface of the cantilever leads further comprises:
disposing the supports on a film; and
disposing the leadframe on the film such that the recessed surface of the cantilever leads are disposed adjacent to at least one of the supports.
3. The method of claim 1 , wherein disposing one or more non-conductive supports adjacent to the recessed surface of the cantilever leads further comprises:
coupling the supports to the leadframe; and
simultaneously disposing the leadframe and the supports to a film.
4. The method of claim 1 , wherein a first portion of the supports adjacent to the recessed surface of the cantilever leads is wider than a second portion of the supports not adjacent to the recessed surface of the cantilever leads.
5. The method of claim 1 , wherein surfaces of the supports are mechanically roughened, plasma etched, coated with adhesion promoters, or doped with adhesion promoters.
6. The method of claim 1 , wherein a configuration of the supports comprises a ring.
7. The method of claim 1 , wherein a configuration of the supports comprises one or more bars.
8. The method of claim 1 , wherein a configuration of the supports comprises a plurality of individual standoffs for supporting the cantilever leads, each of the standoffs supporting one or more of the cantilever leads.
9. The method of claim 1 , wherein a material of the supports comprises ceramic, plastic, or anodized metal.
10. The method of claim 1 , wherein a combined thickness of the supports and the cantilever leads at the second end is substantially equal to the first thickness.
11. The method of claim 1 , wherein the die is mounted on a die pad in the mounting area of the leadframe, and wherein encapsulating further comprises encapsulating at least a portion of the die pad.
12. A method of manufacturing a semiconductor package, which contains a semiconductor die and a metallic leadframe, comprising:
affixing the semiconductor die on a die pad portion of the leadframe, placing a non-conductive supporting member underneath a first end of a cantilever lead; and wire-bonding the cantilever lead to a bond pad on the semiconductor die.
13. The method of claim 12 , further comprising molding the semiconductor die and the bond-wire with an encapsulant, exposing a surface of the nonconductive supporting member.
14. The method of claim 12 , in which the non-conductive supporting member supports a second cantilever lead.
15. The method of claim 14 , in which the non-conductive supporting member is a ring.
16. The method of claim 14 , in which the non-conductive supporting member is a bar.
17. The method of claim 12 , in which the non-conductive supporting member includes ceramic, plastic, or anodized metal.
18. The method of claim 12 , in which the combined thickness of the supporting member and the cantilever lead at the first end is substantially equal to the thickness of the cantilever lead at a second end.
19. The method of claim 18 , further comprising molding the semiconductor die and the bond-wire with an encapsulant, exposing a surface of the nonconductive supporting member and a surface of the second end of the cantilever lead.