Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2000-11-16
2003-03-11
Martin, David (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S784000, C361S820000, C174S255000, C174S260000, C257S676000, C257S684000
Reexamination Certificate
active
06532157
ABSTRACT:
BACKGROUND
1. Technical Field
This invention pertains to semiconductor packaging in general, and in particular, to semiconductor packages having portions fixed at an angle relative to one another.
2. Related Art
The current trend in electronics toward devices that are more compact and yet more functional has resulted in the need to house more components in smaller volumes, and to dissipate more heat from such smaller volumes. This trend has created a concomitant demand for semiconductor packages capable of meeting these same objectives.
To achieve a greater power dissipation from a semiconductor package of a given size, it is known to mount the bottom surface of a high-power semiconductor device, e.g., a die, or “microchip,” directly on a thermally conductive “heat slug” in the package, and to couple the heat slug through the bottom of the package to a heat sink disposed above, below, or within a printed circuit board (“PCB”) to which the package is mounted and electrically connected. However, since the thermal coupling of the die to the heat sink and the electrical connection of the die to the PCB are located in the same or parallel planes, this arrangement prevents one or both of the thermal coupling and the electrical connection to the die from being as short and direct as possible.
Another known approach is to reverse the foregoing orientation of the die and heat slug such that the die is thermally coupled through the top of the package to a heat sink disposed above the package. However, this arrangement is inconsistent with a requirement for a low-profile package.
It is also known to connect a fiber optic cable to the top surface of a semiconductor package such that the end of the cable is optically coupled directly to the active surface of an optical chip contained therein. However, since the fiber bundle extends upright from the package, it also extends upright relative to a PCB to which the package is mounted, and hence, this optical coupling arrangement is also inconsistent with a low-profile package.
A need therefore exists for a semiconductor package in which a semiconductor die can be thermally and/or optically coupled directly to a heat sink and/or an optical cable in a first plane, and electrically connected to an associated PCB in a distinct, divergent second plane, without interference between the thermo-optical couplings and the electrical connections to the die, and which also satisfies the requirement of a low profile package.
SUMMARY
This invention provides several embodiments of a low-profile semiconductor package in which a semiconductor device can be thermally and/or optically coupled directly to a heat sink and/or an optical cable in a first plane, and electrically connected to an associated PCB located in a second plane that is distinct and divergent from the first plane, without interference between the respective couplings and the connections to the device.
One embodiment of the novel package comprises a rigid dielectric, e.g., a ceramic, substrate having two portions that are joined to one another at respective adjacent margins thereof to form an angle, e.g., a right angle, between the two portions. Each portion has electrically conductive paths connected through the angle to the electrically conductive paths in the other portion. In one advantageous embodiment, this connection is effected by resilient, arcuate metal leads extending between the respective adjacent margins of the two substrate portions to accommodate angular tolerances between surfaces to which the two portions are respectively mounted.
A semiconductor device, such as a die or a “micro-machine,” is mounted to a first one of the portions in electrical connection with the electrically conductive paths thereof. An array of electrically conductive balls, lands, or pins is mounted on the second one of the portions and in electrical connection with the conductive paths thereof for connecting electrical signals between the package and, e.g., a PCB to which the package is mounted.
In a high-power embodiment, the device can be mounted on a threaded stud projecting from the first portion of the substrate to enable intimate thermal coupling of the device to a heat sink, such as a cold wall. Optionally, associated low-power active or passive components can also be mounted on the second portion to achieve an enhanced component packaging density. In another embodiment, an optical connector can project from the first portion of the substrate to enable direct optical coupling of the device to the end of a fiber optic cable.
By locating thermo-optical couplings and electrical connections to the device in two different, non-parallel planes, both can be effected directly and efficiently without interfering with the other in a package having a relatively low profile.
A better understanding of the above and other features and advantages of the invention may be had from a consideration of the detailed description below of some exemplary embodiments thereof, particularly if such consideration is made in conjunction with the appended drawings.
REFERENCES:
patent: 5057907 (1991-10-01), Ooi
patent: 5583377 (1996-12-01), Higgins, III
patent: 5864132 (1999-01-01), Holcombe
Glenn Thomas P.
Hollaway Roy D.
Webster Steven
Amkor Technology Inc.
Lindinger Michael L.
Martin David
Parsons James F.
Skjerven Morrill LLP
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