Leadframe for a semiconductor device having leads with land electrodes
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsMasanori Minamio, Osamu Adachi
Life of this patent
Estimating the term…
Abstract
In a leadframe for an LGA package, a lead member is pressed downward to form a land lead with a half-cut portion and a land portion. The land portion, whose bottom will be a land electrode, is inclined at a predetermined angle and the bottom of the land portion is made lower than that of a lead. Thus, in a resin molding process using a seal sheet, the land electrode is forced into, and strongly adhered to, the seal sheet when pressure is applied through dies, and no resin encapsulant reaches the land electrode. As a result, no resin bur will be left on the land electrode of the land lead.
Claims8
A leadframe comprising:
- a frame rail made of a metal plate;
- a die pad for mounting a semiconductor chip thereon, the die pad being disposed approximately in a center region of an opening of the frame rail;
- support leads, one end of each said support lead supporting the die pad, the other end of the support lead being connected to the frame rail;
- a first group of leads, one end of each said lead of the first group extending toward the die pad, the other end of the lead of the first group being connected to the frame rail, part of the bottom of the lead of the first group being used as a land electrode of a first group;
- and
- a second group of leads, one end of each said lead of the second group extending toward the die pad and being closer to the die pad than the end of each said lead of the first group is, the other end of the lead of the second group being connected to the frame rail, part of the bottom of the lead of the second group being used as a land electrode of a second group,
- wherein the first and second groups of land electrodes are arranged in two lines, and
- wherein each said lead of the second group is arranged such that the bottom of each said land electrode of the second group is lower than the bottom of each said land electrode of the first group, and
- wherein said part of the lead of the second group is inclined downward corresponding to said land electrode of the first group.
Dependencies are inferred from the claim text.