Leadless leadframe packaging panel featuring peripheral dummy leads
AssigneeNational Semiconductor Corporation
InventorsSanthiran Nadarajah, Sharon Ko Mei Wan, Chan Peng Yeen
Life of this patent
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Abstract
Methods and apparatuses for providing leadless leadframes with dummy contact leads are disclosed. A leadframe is described that includes an enclosed frame having two lengthwise portions and two widthwise portions. The leadframe also includes a device area array with dummy contact leads formed on the peripheral edges of the device area array. Furthermore, dummy contact leads are positioned along a tie bar such that they are directly opposite corresponding contact leads. By cutting along the tie bar, dummy contact leads are separated from the device area array.
Claims21
An electrically conductive leadframe for manufacturing semiconductor device packages comprising:
- an enclosed frame having two lengthwise portions and two widthwise portions;
- and
- a pair of lengthwise tie bars, each lengthwise tie bar extending along an inner edge of a respective lengthwise portion of the frame, each of the lengthwise tie bars having an inner array of contact leads extending towards an inner region of the frame and an outer array of contact leads extending in an opposite direction from the inner array of contact leads, each inner contact lead having a corresponding outer contact lead of substantially the same size and positioned directly opposite the corresponding outer contact lead along the lengthwise tie bars, the outer array of contact leads being adjacent to a lengthwise portion of the frame.
A leadless leadframe for use in semiconductor packaging, comprising:
- a conductive sheet of material having a two dimensional array of overlapping device areas defined thereon, the array defined by a plurality of lengthwise and widthwise outer edges, the array including,
- lengthwise tie bars that extend adjacent to each of the lengthwise outer edges, each lengthwise tie bar having opposing edges where contact leads extend off each of the opposing edges, each contact lead having a corresponding contact lead of substantially the same size and positioned directly opposite the corresponding contact lead.
A lead frame panel suitable for use in packaging an array of integrated circuits in leadless leadframe style packaging, the lead frame panel being formed from a conductive sheet, the lead frame panel comprising:
- a matrix of tie bars that extend in substantially perpendicular rows and columns to define a two dimensional array of immediately adjacent device areas separated only by the tie bars, each device area being suitable for use in an independent integrated circuit package;
- a multiplicity of conductive contacts, the conductive contacts being mechanically carried by the tie bars, wherein each device area has a plurality of associated contacts;
- and
- support rails that carry the tie bars, the tie bars including at least some intermediary tie bars that separate immediately adjacent device areas and a plurality of peripheral tie bars, each peripheral tie bar being positioned between one of the rails and associated device areas;
- and
- a plurality of dummy contacts that are not intended for use in any of the integrated circuit packages, the dummy contacts being suspended by the peripheral tie bars, wherein each dummy contacts is located directly opposite a corresponding contact carried by the peripheral tie bars, and wherein each dummy contacts is identical in shape to a corresponding contact carried by the peripheral tie bars.
Dependencies are inferred from the claim text.