Electrical connectors – Preformed panel circuit arrangement – e.g. – pcb – icm – dip,... – With provision to conduct electricity from panel circuit to...
Reexamination Certificate
1998-10-29
2001-06-19
Abrams, Neil (Department: 2839)
Electrical connectors
Preformed panel circuit arrangement, e.g., pcb, icm, dip,...
With provision to conduct electricity from panel circuit to...
Reexamination Certificate
active
06247938
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to a solderless connector with multiple modes of compliance and to a replaceable chip module utilizing the present connector for electrically connecting one or more first circuit members to a second circuit member.
BACKGROUND OF THE INVENTION
The current trend in connector design for those connectors utilized in the computer field is to provide both high density and high reliability connectors between various circuit devices. High reliability for such connections is essential due to potential system failure caused by misconnections of devices. Further, to assure effective repair, upgrade, testing and/or replacement of various components, such as connectors, cards, chips, boards, and modules, it is highly desirable that such connections be separable and reconnectable in the final product.
Pin-type connectors soldered into plated through holes or vias are among the most commonly used in the industry today. Pins on the connector body are inserted through plated holes or vias on a printed circuit board and soldered in place using conventional means. Another connector or a packaged semiconductor device is then inserted and retained by the connector body by mechanical interference or friction. The tin lead alloy solder and associated chemicals used throughout the process of soldering these connectors to the printed circuit board have come under increased scrutiny due to their environmental impact. The plastic housings of these connectors undergo a significant amount of thermal activity during the soldering process, which stresses the component and threatens reliability.
The soldered contacts on the connector body are typically the means of supporting the device being interfaced by the connector and are subject to fatigue, stress deformation, solder bridging, and co-planarity errors, potentially causing premature failure or loss of continuity. In particular, as the mating connector or semiconductor device is inserted and removed from the present connector, the elastic limit on the contacts soldered to the circuit board may be exceeded causing a loss of continuity. These connectors are typically not reliable for more than a few insertions and removals of devices. These devices also have a relatively long electrical length that can degrade system performance, especially for high frequency or low power components. The pitch or separation between adjacent device leads that can be produced using these connectors is also limited due to the risk of shorting.
Another electrical interconnection method is known as wire bonding, which involves the mechanical or thermal compression of a soft metal wire, such as gold, from one circuit to another. Such bonding, however, does not lend itself readily to high density connections because of possible wire breakage and accompanying mechanical difficulties in wire handling.
An alternate electrical interconnection technique involves placement of solder balls or the like between respective circuit elements. The solder is reflowed to form the electrical interconnection. While this technique has proven successful in providing high density interconnections for various structures, this technique does not allow facile separation and subsequent reconnection of the circuit members.
An elastomer having a plurality of conductive paths has also been used as an interconnection device. The conductive elements embedded in the elastomeric sheet provide an electrical connection between two opposing terminals brought into contact with the elastomeric sheet. The elastomeric material that supports the conductive elements compresses during usage to allow some movement of the conductive elements. Such elastomeric connectors require a relatively high force per contact to achieve adequate electrical connection, exacerbating non-planarity between mating surfaces. Location of the conductive elements is generally not controllable. Elastomeric connectors may also exhibit a relatively high electrical resistance through the interconnection between the associated circuit elements. The interconnection with the circuit elements can be sensitive to dust, debris, oxidation, temperature fluctuations, vibration, and other environmental elements that may adversely affect the connection.
The problems associated with connector design are multiplied when multiple integrated circuit devices are packaged together in functional groups. The traditional way is to solder the components to a printed circuit board, flex circuit, or ceramic substrate in either a bare die silicon integrated circuit form or packaged form. Multi-chip modules, ball grids, array packaging, and chip scale packaging have evolved to allow multiple integrated circuit devices to be interconnected in a group.
One of the major issues regarding these technologies is the difficulty in soldering the components, while ensuring that reject conditions do not exist. Many of these devices rely on balls of solder attached to the underside of the integrated circuit device which is then reflown to connect with surface mount pads of the printed circuit board, flex circuit, or ceramic substrate. As discussed above, these joints have not been proven to be extremely reliable nor easy to inspect for defects. The process to remove and repair a damaged or defective device is costly and many times results in unusable electronic components and damage to other components in the functional group.
Multi-chip modules have had slow acceptance in the industry due to the lack of large scale known good die for integrated circuits that have been tested and burned-in at the silicon level. These dies are then mounted to a substrate which interconnect several components. As the number of devices increases, the probability of failure increases dramatically. With the chance of one device failing in some way and effective means of repairing or replacing currently unavailable, yield rates have been low and the manufacturing costs high.
BRIEF SUMMARY OF THE INVENTION
The present invention is directed to an electrical connector for electrically connecting a first circuit members to a second circuit member. The electrical connector includes an electrically insulative connector housing having one or more apertures. A first contact member is located in the aperture. The first contact member has at least one helical portion and a first circuit interface portion configured to engage with the first circuit member at a first circuit interface. A resilient, dielectric encapsulation material defines a first compliant member surrounding a portion of the first contact member within the aperture. The first compliant member provides a first mode of compliance. The first contact member defines a second compliant member. At least one aperture side wall is positioned to engage with the first contact member when in a compressed mode, whereby the first and second compliant members exhibit a second mode of compliance in response to engagement with the aperture side wall.
The compressed mode comprises elastic deformation of the contact member and encapsulating material. The first contact member typically includes a second circuit interface portion configured to engage with a second circuit member at a second circuit interface that operates substantially as the first circuit interface portion.
The first circuit interface portion can be a shape complementary to a shape of the connector member. The resilient contact member is typically a piece of a conductive sheet material. The first circuit interface portion can provide a wiping engagement with the first circuit member. The first circuit member can be a packaged and an unpackaged integrated circuit device. The first circuit interface portion is capable of engaging with a connector member selected from the group consisting of an edge card, a j-lead device, a flex circuit, a ribbon connector, a cable, a ball grid array (BGA), a land grid array (LGA), a plastic leaded chip carrier (PLCC), a pin grid array (PGA), a small outline integrated circuit (SOIC), a dual in-line package (DIP), a
Abrams Neil
Faegre & Benson LLP
Gryphics, Inc.
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