Lead for integrated circuit package
A circuit package for housing semiconductor or other integrated circuit devices (“die”) includes a high-copper flange, one or more high-copper leads and a liquid crystal polymer frame molded to the flange and the leads. The leads include one or more lead retention features to mechanically interlock with the frame. During molding, a portion of the frame freezes in or adjacent these lead retention features.
1 . A lead for a semiconductor circuit package, comprising a metal conductor and defining a plurality of laterally spaced holes therethrough.
2 . The lead of claim 1 , wherein each of the plurality of holes is rectangular.
3 . The lead of claim 2 , wherein, in a lateral cross-section of the lead and passing through the plurality of holes, a cross-sectional area of the plurality of holes is less than or equal to about 25% of a cross-sectional area of the lead.
4 . The lead of claim 1 , further comprising a frame molded thereto, a portion of the frame extending through the plurality of holes.
5 . The lead of claim 4 , wherein the frame comprises a liquid crystal polymer.
6 . The lead of claim 1 , wherein the lead comprises at least 50% copper.
7 . The lead of claim 1 , wherein the lead comprises at least 97% copper.
8 . The lead of claim 1 , wherein the lead comprises an alloy of copper and at least one material chosen from a group comprising iron, phosphorus, zinc, zirconium, cobalt, tin, magnesium, nickel, chromium, titanium and silicon.
9 . The lead of claim 8 , wherein the alloy contains at least 97% copper.
10 . The lead of claim 1 , wherein the lead comprises:
between about 2.1% and about 2.6% iron;
between about 0.015% and about 0.15% phosphorous;
between about 0.05% and 0.2% zinc; and
the balance copper.
11 . A lead for a semiconductor circuit package, comprising a metal conductor having a lead retention feature proximate to one end thereof.
12 . The lead of claim 11 , wherein:
the lead retention feature comprises an outward-facing portion; and further comprising:
a frame molded to the metal conductor, a portion of the frame abutting the outward-facing portion of the lead retention feature.
13 . The lead of claim 12 , wherein the frame comprises a liquid crystal polymer.
14 . The lead of claim 11 , wherein the retention feature comprises a hooked edge.
15 . The lead of claim 11 , wherein the retention feature comprises a ridge.
16 . The lead of claim 11 , wherein the retention feature comprises a groove.
17 . The lead of claim 11 , wherein the lead comprises at least 50% copper.
18 . The lead of claim 11 , wherein the lead comprises at least 97% copper.
19 . The lead of claim 11 , wherein the lead comprises an alloy of copper and at least one material chosen from a group comprising iron, phosphorus, zinc, zirconium, cobalt, tin, magnesium, nickel, chromium, titanium and silicon.
20 . The lead of claim 19 , wherein the alloy contains at least 97% copper.
21 . The lead of claim 11 , wherein the lead comprises: between about 2.1% and about 2.6% iron;
between about 0.015% and about 0.15% phosphorous;
between about 0.05% and 0.2% zinc; and
the balance copper.
22 . The lead of claim 21 , wherein the retention feature comprises a hooked edge.
23 . The lead of claim 21 , wherein the retention feature comprises a ridge.
24 . The lead of claim 21 , wherein the retention feature comprises a groove.
25 . A method for fabricating a lead of a circuit package, comprising:
stamping a lead frame from a material comprising at least about 50% copper.