US PATENT SUBCLASS 257 / 666
LEAD FRAME

Current as of: June, 1999
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257 /   HD   ACTIVE SOLID-STATE DEVICES (E.G., TRANSISTORS, SOLID-STATE DIODES)

666LEAD FRAME {10}
667  DF  .~> With dam or vent for encapsulant
668  DF  .~> On insulating carrier other than a printed circuit board
669  DF  .~> With stress relief
670  DF  .~> With separate tie bar element or plural tie bars {1}
672  DF  .~> Small lead frame (e.g., "spider" frame) for connecting a large lead frame to a semiconductor chip
673  DF  .~> With bumps on ends of lead fingers to connect to semiconductor
674  DF  .~> With means for controlling lead tension
675  DF  .~> With heat sink means
676  DF  .~> With structure for mounting semiconductor chip to lead frame (e.g., configuration of die bonding flag, absence of a die bonding flag, recess for LED)
677  DF  .~> Of specified material other than copper (e.g., Kovar (T.M.))

DEFINITION

Classification: 257/666

LEAD FRAME:

(under the class definition) Subject matter wherein the active solid-state device is provided with a conductive metal network which may have relatively large area portions, commonly called pads or flags, for direct contact with semiconductor chips or dice, and lead elements for facilitating electrical interconnection of the chips or dies via intermediate (e.g., jumper) connections to other electronic devices or components.

(1) Note. Lead frames also have other portions, usually called "ties", which interconnect the pad or flag portions with the lead portions prior to assembly of the lead frame in an electronic package or housing, but which are removed during package assembly.

(1) Note. See the illustration, below: [figure]

SEE OR SEARCH CLASS

29, Metal Working,

739+, especially subclass 741, for means to fasten electrical component to wiring means, base, or substrate, including a multi-lead component; and subclass 834 for beam lead frames or beam lead devices.

174, Electricity: Conductors and Insulators, 52.4, for flat pack electronic device mounting means.

361, Electricity: Electrical Systems and Devices,

813, for lead frames, per se, not associated with a solid-state active electronic device of the type classified in Class 257.

428, Stock Material or Miscellaneous Articles,

571+, for stock materials of metal which have marginal indexing features or weakened portion for severing. Lead frames are commonly made in long strips of repeating patterns with such indexing and/or severing features.

438, Semiconductor Device Manufacturing: Process, particularly

111+, and 123+ for methods of packaging utilizing a lead frame; see the search notes therein.