Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
1999-05-04
2001-01-30
Gerrity, Stephen F. (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S830000, C029S842000, C029S876000, C029S883000, C439S066000, C439S071000
Reexamination Certificate
active
06178629
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to a replaceable chip module 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 a replaceable chip module for electrically connecting one or more first circuit members to a second circuit member. The replaceable chip module includes a module housings having a plurality of device sites each capable of receiving at least one first circuit member. A first connector is located in each of the device sites. The first connector comprises one or more first contact members comprising a first compliant member defining a first circuit interface engageable with the first circuit member, a resilient, dielectric encapsulating material defining a second compliant member surrounding a portion of the first contact member, the first and second compliant members providing a first mode of compliance, and at least one end stop positioned to engage with the first contact member in a second mode of compliance. A second connector is positioned to electrically connect the first connector to the second circuit member.
In one embodiment, second connector comprises a second contact member having substantially the same structure as the first contact member. In one embodiment, the first contact member and a second contact member comprise a single contact member extending between the first and second circuit members. A third electrical connector can optionally be provided for electrically connecting the second circuit member to a third circuit member. In one embodiment, the third circuit member comprises the present replaceable chip module.
The first connector has multiple modes of compliance and an initial insertion force differing from a secondary insertion force. The first connector has multiple compliant members that can be independently adjusted to accommodate a wide range of first and second circuit members. The first connector allows the contact members to be arranged with a pitch of less than 0.50 millimeters without shorting. The multiple compliant contact members accommodate a wide range of thermal and vibrational effects, and can be configured to accommodate a wide range of compression distances.
The present invention is also directed to a method of utilizing the present replaceable chip module during mu
Faegre & Benson LLP
Gerrity Stephen F.
Gryphics, Inc.
Sands Rhonda E
LandOfFree
Method of utilizing a replaceable chip module does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of utilizing a replaceable chip module, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of utilizing a replaceable chip module will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2449509