Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package – For plural devices
Reexamination Certificate
1999-09-22
2001-10-02
Chaudhuri, Olik (Department: 2814)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
For plural devices
C257S686000, C257S738000, C257S778000, C257S779000, C257S780000, C361S717000, C361S748000, C361S761000, C361S764000
Reexamination Certificate
active
06297551
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to integrated circuit devices, and more particularly to flip-chip IC packages having improved electromagnetic interference (EMI) characteristics.
BACKGROUND OF THE INVENTION
A variety of integrated circuit packages are used for packaging semiconductor devices. Dual in-line packages (DIPs), pin grid arrays (PGAs), and surface mount packages have been widely used for many years. More recent package embodiments use flip-chip approaches and advanced interconnection substrates. Recessed chip multichip module (MCM) packages have been introduced in manufacture to reduce the package profile. In general, the state of the art package designs have relatively good EMI performance due largely to the short length of interconnections in BGA or solder bumped packages, and the compact interconnect strategy made possible by state of the art multichip modules. However, as operating frequencies continue to rise, even these package designs suffer from EMI problems. Operating frequencies in wireless applications are in the several to tens of gigabit range. Specialized computing devices also operate at these speeds. In these high frequency applications, even the relatively short leads of BGA and solder bumped packages are susceptible to stray electromagnetic radiation.
To combat EMI problems in IC packages, EMI shields are often incorporated in the package design. So-called Faraday cages in the form of wire grids have been built around the IC chip to shield the interconnections from stray fields. Metal cans are also provided to “encapsulate” IC chips and leads. These cans are usually fabricated using stamped metal (typically copper or aluminum). Consequently they add cost, size and weight to the IC package. In an effort to reduce the size and weight of the can, resort is made to perforating portions of the can. This reduces the bulk of the can but does not decrease the cost. Moreover, it reduces the effectiveness of the EMI shield.
As is known, EMI is disruptive to the proper operation of circuit components located near the source of the EMI. Accordingly, there is an identifiable need to reduce EMI susceptibility.
SUMMARY OF THE INVENTION
To achieve reduced EMI susceptibility, an integrated circuit package has been designed that avoids the drawbacks of the prior art packages described outlined above. In accordance with a principle aspect of the invention, a recessed flip-chip package is provided with an internal EMI shield which is incorporated into the package itself. The flip-chip MCM tile is metallized around the external surfaces of the substrate. The PCB into which the MCM tile is recessed, hereinafter referred to as the MCM PCB, is provided with a solder wall corresponding to the peripheral shape of the MCM tile, and the MCM tile and MCM PCB are joined with the solder wall completely surrounding the IC chip. The solder wall on the MCM PCB is connected to a ground plane that surrounds the cavity into which the IC device(s) is recessed. In this manner the MCM cavity is completely isolated from stray EMI.
REFERENCES:
patent: 4903120 (1990-02-01), Beene et al.
patent: 5198963 (1993-03-01), Gupta et al.
patent: 5521435 (1996-05-01), Mizukoshi
patent: 5541450 (1996-07-01), Jones et al.
patent: 5608262 (1997-03-01), Degani et al.
patent: 5639989 (1997-06-01), Higgins, III
patent: 5646828 (1997-07-01), Degani et al.
patent: 5715144 (1998-02-01), Ameen et al.
patent: 5869894 (1999-02-01), Degani et al.
patent: 5953213 (1999-09-01), Napierala
patent: 6125042 (2000-09-01), Verdi et al.
patent: 6137693 (2000-10-01), Schwiebert et al.
patent: 6154370 (2000-11-01), Degani et al.
patent: 6201403 (2001-03-01), Rollin et al.
patent: 60-10764 (1985-01-01), None
patent: 5-48000 (1993-02-01), None
Dudderar Thomas Dixon
Kossives Dean Paul
Low Yee Leng
Agere Systems Guardian Corp.
Chambliss Alonzo
Chaudhuri Olik
Thomas Kayden Horstemeyer & Risley LLP
Wilde Peter V. D.
LandOfFree
Integrated circuit packages with improved EMI characteristics does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Integrated circuit packages with improved EMI characteristics, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Integrated circuit packages with improved EMI characteristics will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2553592