Metal plane support for multi-layer lead frames and a process for manufacturing such frames

A metal plane support structure of a metal plane of a semiconductor device multiple layer lead frame, comprising:

• a first metal strip having first and second parallel longitudinal edges, spaced by a first dimension in a direction transverse to the first and second parallel longitudinal edges;
• a metal plane defined in the first metal strip, of a substantially rectangular configuration and having a corresponding rectangular periphery defined by a first pair of first and second parallel peripheral edges, respectively parallel to the first and second parallel longitudinal edges of the first metal strip and spaced in the transverse direction by a second dimension less than the first dimension, and a second pair of first and second parallel peripheral edges extending in the transverse direction, the metal plane being substantially centered in the first metal strip, in the transverse direction;
• a pair of first and second side rails defined in the metal strip and having respective outer longitudinal edges defined by the respective first and second parallel longitudinal edges of the metal strip and first and second inner longitudinal edges respectively spaced by a common, third dimension in the transverse direction from the first pair of first and second parallel peripheral edges of the metal plane;
• and
• at least first and second support bars defined in the first metal strip and extending between and interconnecting the corresponding first and second side rails, respectively, with the first and second parallel longitudinal peripheral edges, respectively, of the metal plane, each of the at least first and second support bars having corresponding, first and second opposite ends, the first ends of the first and second support bars defining integral connections with the first and second parallel longitudinal peripheral edges, respectively, of the metal plane and each integral connection having a separating portion extending longitudinally therein and aligned with the corresponding one of the first and second parallel peripheral edges of the metal plane and the second ends of the first and second support bars defining integral connections with the first and second side rails, respectively, wherein the multi-layer lead frame further comprises a lead frame support formed of a second metal strip having a pair of third and fourth parallel longitudinal edges spaced by a fourth transverse dimension, a lead frame of generally rectangular configuration being defined in, and centrally positioned between the parallel longitudinal edges of, the lead frame support, wherein:
• the first transverse dimension of the first metal strip is greater than the fourth transverse dimension of the second metal strip;
• and
• the first and second metal strips are juxtaposed such that the metal plane of the first metal strip is aligned with the lead frame of the second metal strip, the pair of first and second side rails of the metal plane support being disposed outwardly, in the transverse direction, of the pair of third and fourth longitudinal edges, respectively, of the second metal strip.

A support structure of a semiconductor device multi-layer lead frame, comprising:

• at least first and second metal strips, each having corresponding first and second parallel longitudinal edges, spaced by a first dimension in a direction transverse to the first and second parallel longitudinal edges and respectively having defined therein alternating plural metal planes of at least first and second different types of metal planes of the multi-layer lead frame, the plural metal planes of a common type being spaced longitudinally in the respective metal strip;
• each of the common metal planes defined in a respective metal strip being of a substantially rectangular configuration and having a corresponding rectangular periphery defined by a first pair of first and second parallel peripheral edges, respectively parallel to the first and second parallel longitudinal edges of the respective metal strip and spaced in the transverse direction by a second dimension less than the first dimension and a second pair of first and second parallel peripheral edges extending in the transverse direction, and being substantially centered in the respective metal strip, in the transverse direction;
• each of the at least first and second metal strips further comprising:
• a pair of first and second side rails defined therein and having respective outer longitudinal edges defined by the respective first and second parallel longitudinal edges thereof and first and second inner longitudinal edges respectively spaced by a common, third dimension in the transverse direction from the first pair of first and second parallel peripheral edges of the common metal planes defined therein, and
• at least first and second support bars defined therein, corresponding to each metal plane and extending between and interconnecting the first and second side rails, respectively, with the first and second parallel longitudinal peripheral edges, respectively, of the corresponding metal plane, each of the at least first and second support bars having corresponding, opposite ends thereof defining respective integral connections with the first and second side rails and with the first and second parallel longitudinal peripheral edges of the metal plane and further having a respective separating portion at the integral connection of the end thereof with the respective one of the first and second parallel peripheral edges of the metal plane;
• and
• a lead frame support formed of a further metal strip having a pair of third and fourth parallel longitudinal edges spaced by a fourth transverse dimension and having defined therein plural lead frames, each of generally rectangular configuration and centrally positioned between the parallel longitudinal edges of the lead frame support and spaced longitudinally therein, wherein:
• the first transverse dimension of each of the at least first and second metal strips is greater than the fourth transverse dimension of the further metal strip, and
• the at least first and second metal strips are juxtaposed such that corresponding, said respective metal planes of the at least first and second types are aligned with each other and with a corresponding lead frame of the further metal strip, the corresponding pairs of first and second side rails of the at least first and second metal plane supports being disposed outwardly, in the transverse direction, of the pair of third and fourth longitudinal edges, respectively, of the further metal strip.