Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
1998-12-18
2001-09-11
Gaffin, Jeffrey (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S767000, C361S795000, C361S794000, C174S260000, C174S261000
Reexamination Certificate
active
06288906
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to circuit boards and in particular the present invention relates to circuit boards having power planes on outer layers.
BACKGROUND OF THE INVENTION
Electronic manufacturers use printed circuit boards to electrically connect integrated circuits, and other electrical components such as capacitors and resistors. Population densities of printed circuit boards have increased with the complexity of circuitry and the reduction in size of components. For example, computer motherboards can include hundreds of components including various integrated circuits and surface mount components.
As printed circuit board designs have increased in complexity, the need for additional interconnect lines between the components coupled to the printed circuit boards have increased. To address this need, manufactures have provided multiple layer printed circuit boards where several layers of conductors are separated by layers of dielectric material. These multiple layer circuit boards are fabricated such that the intermediate conductor layers provide power and ground planes to the printed circuit board. The outer layers of the printed circuit board, therefore, are patterned to provide the interconnects and mounting pads for components which are ultimately coupled to the printed circuit board.
FIG. 1
illustrates a multiple layer printed circuit board where the intermediate layers provide power, and the outer layers provide interconnect traces.
The conductive layers of the multiple layer printed circuit boards are connected to each other using vias which are plated with conductive material to provide plated through holes. The vias are located across the printed circuit board and connected to mounting locations on the outer conductive planes using conductive traces. That is, mounting pads for integrated circuits and surface mount components are not directly connected to plated through holes, but are connected to the plated through hole locations using a patterned conductive trace.
With the increased population density of integrated circuits, concerns about electromagnetic interference (EMI), power/heat dissipation, and power delivery increase. For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a printed circuit board which addresses the above concerns while maintaining current circuit board assembly quality, including solder joints.
SUMMARY OF THE INVENTION
A multiple layer printed circuit board comprising a first intermediate conductive layer having conductive interconnect traces formed therein, a first outer conductive layer located above the first intermediate conductive layer and separated from the first intermediate conductive layer by a first dielectric layer, and a second outer conductive layer located below the first intermediate conductive layer and separated from the first intermediate conductive layer by a second dielectric layer. The first outer conductive layer is coupled to a first power supply voltage to provide a first power supply conductive plane, and the second outer conductive layer is coupled to a second power supply voltage to provide a second power supply conductive plane. A plurality of plated vias traverse through the first intermediate conductive layer, the first and second outer conductive layers, and the first and second dielectric layers to selectively couple at least two of the conductive layers. Circuit mounting pads are formed in either the first or second outer conductive layers, the circuit mounting pads are sized to accept a circuit component. Wherein one of the plurality of plated vias traverses through one of the circuit mounting pads such that the plated via is located in a region of the mounting pad which is beneath the circuit component when the circuit component is connected to the mounting pad.
A printed circuit board mounting pad comprises a first conductive region sized to accept a circuit device intended to be soldered to the mounting pad. The first conductive region is located beneath the circuit device when the circuit device is soldered to the mounting pad. A second conductive region is provided and integral with the first conductive region. The second conductive region is located laterally outside of the circuit device when the circuit device is soldered to the mounting pad, such that the second conductive region provides a solder fillet area. A plated via is located in the first conductive region and extending downwardly through the mounting pad for electrical interconnection with conductive regions located below the mounting pad.
REFERENCES:
patent: 4910643 (1990-03-01), Williams
patent: 5249098 (1993-09-01), Rostoker et al.
patent: 5278524 (1994-01-01), Mullen
patent: 5396397 (1995-03-01), McClanahan et al.
patent: 5557502 (1996-09-01), Banerjee et al.
Joy Steve
Scheyer-Furnanz Julie
Sprietsma John T.
Gaffin Jeffrey
Intel Corporation
Schwegman Lundberg Woessner & Kluth P.A.
Tran Thanh Y.
LandOfFree
Multiple layer printed circuit board having power planes on... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multiple layer printed circuit board having power planes on..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multiple layer printed circuit board having power planes on... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2531875