Whisker-free lead frames

a lead frame and whisker technology, applied in the field of tin containing interconnects, can solve problems such as the potential to produce mechanical instabilities, and achieve the effect of reducing the proclivity to induce mechanical instabilities
US20060068218A1Inactive Publication Date: 2006-03-30AGERE SYST INC +1
13 Cites 63 Cited by

Patent Information

Authority / Receiving Office
US · United States
Current Assignee / Owner
AGERE SYST INC
Publication Date
2006-03-30
Estimated Expiration
Not applicable · inactive patent

Smart Images

  • Figure 1
    Figure 1
  • Figure 2
    Figure 2
  • Figure 3
    Figure 3
Patent Text Reader

Abstract

The electrical and mechanical properties of structures such as lead frames and other electrical / electronic devices containing, during processing, copper / tin interfaces are improved by introduction of nickel to such interface. Typically, a weight percentage of nickel to tin in the range 1 to 12 weight percent yields upon melting of the tin, an intermetallic compound with essentially no occluded, unbound tin. Thus undesirable anomalous structures such as tin needles and substantially non-planar interface compositions are avoided. Advantageously a nickel / tin / copper intermetallic interface that is substantially planar is formed in the substantial absence of needle-like tin structures.
Need to check novelty before this filing date? Find Prior Art

Description

TECHNICAL FIELD

[0001] This invention relates to tin containing interconnects for electronic and electrical devices and in particular to tin containing interconnects that avoid formation of tin whiskers. BACKGROUND OF THE INVENTION

[0002] For electrical and electronic devices, typically electrical connections are made through the expedient of a lead frame or other copper containing structures. For example, in the fabrication of integrated circuits, a silicon body having electronic circuitry is connected to a metal e.g. copper, lead frame such as shown in FIG. 1 at 2 with the chip positioned at 3 and connections between bonding pads on the chip and the lead frame shown at 4. After the chip is bonded to the lead frame, the chip is encapsulated typically in a polymer composition. The strip, 6, in FIG. 1 is removed from the lead frame in a process generally denominated trimming. Thus, after trimming, the individual leads, 7, are no longer mechanically connected on one end. The leads are...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More