Electricity: conductors and insulators – Boxes and housings – Hermetic sealed envelope type
Reexamination Certificate
1998-01-09
2002-03-26
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Boxes and housings
Hermetic sealed envelope type
C257S666000, C257S668000, C257S692000
Reexamination Certificate
active
06362426
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to integrated circuit semiconductor chips. More particularly, it pertains to leadframes for bonding with the integrated circuits.
BACKGROUND OF THE INVENTION
Integrated circuit manufacturers face many design challenges, including reducing the amount of noise in the integrated circuit. Resistance, capacitance and inductance, parasitics of an integrated circuit package, can result in increased signal delays and signal distortions in the electrical signals transmitted to and from the integrated circuit.
Two sources of noise in an integrated circuit package are switching noise and crosscoupling noise, or crosstalk. Switching noise may be an inductive voltage spike that occurs on a conductive path as the result of rapid current switching in the conductive path. Crosstalk is the undesirable appearance of an electrical current in a conductive path as a result of mutual capacitance and inductance between the conductive path and other nearby conductive paths. At higher frequencies, the integrated circuit is even more susceptible to noise.
One approach to reduce noise in an integrated circuit is to increase spacing between transmission lines, such as leads of a leadframe 100 as shown in FIG.
1
. The individual leads 110 forming a right angle are curved in a small portion of the lead and have tightly radiused corners
118
. However, as integrated circuits and electronic equipment become smaller and more complex, spacing transmission lines farther apart becomes increasingly difficult, if not impossible.
Another approach to reduce noise is to reduce the length of the transmission line on a leadframe by using diagonal leads. While diagonal leads minimize the length of the leads, the spacing between the leads would also be decreased. The decreased spacing would increase the overall crosstalk between the leads, and would therefore be undesirable.
Accordingly, there is a need for an integrated circuit package in which the above benefits are achieved and the above problems overcome.
SUMMARY OF THE INVENTION
The present invention solves the above-mentioned needs in the art and other needs which will be understood by those skilled in the art upon reading and understanding the present specification.
A leadframe is provided comprising, in part, a first and second set of conductors. The leadframe is adapted for coupling with a semiconductor integrated circuit. The conductors of the leadframe extend radially from a first end to a second end such that a portion of each conductor has a generally arcuate shape between the first and second end. In one embodiment, the first end of the conductor is for coupling with a printed circuit board, and the second end is for coupling with a semiconductor die. Alternatively, each conductor is sized and spaced such that the line spacing remains constant.
In another embodiment, the conductors have a plurality of segments. Each conductor has at least three segments disposed between the first end and the second end. The segments forming the conductors are disposed such that a portion of each conductor generally has an arcuate shape. In another embodiment, the segments each have substantially the same length. Alternatively, the segments have varying lengths.
In one embodiment, an integrated circuit package is provided comprising a leadframe having a plurality of leads, at least one semiconductor die coupled with the plurality of leads, and an insulating enclosure encapsulating the die and a portion of the leadframe. The leads each extend radially from a first end to a second end such that a portion of each lead has a generally arcuate shape. Alternatively, in another embodiment, the leads each have at least three segments disposed between the first end and the second end.
REFERENCES:
patent: 4743956 (1988-05-01), Olla et al.
patent: 4974053 (1990-11-01), Kinoshita et al.
patent: 5115298 (1992-05-01), Loh
patent: 5138430 (1992-08-01), Gow, 3rd, et al.
patent: 5200364 (1993-04-01), Loh
patent: 5313102 (1994-05-01), Lim et al.
patent: 5397916 (1995-03-01), Normington
patent: 5457340 (1995-10-01), Templeton, Jr. et al.
patent: 5569956 (1996-10-01), Chillara et al.
Corisis David J.
Harrison Ronnie M.
Micro)n Technology, Inc.
Ngo Hung V
Reichard Dean A.
TraskBritt
LandOfFree
Radiused leadframe does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Radiused leadframe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Radiused leadframe will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2825271