US 6,475,011 B1Granted

Land grid array socket actuation hardware for MCM applications

AssigneeInternational Business Machines Corporation

InventorsArvind K. Sinha, Roger D. Hamilton, John L. Colbert, John S. Corbin, Jr., Danny E. Massey

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Abstract

An apparatus for applying force to a multi-chip module, a printed wiring board and an interposer to facilitate electrical contact there-between, includes a plurality of load posts, a load transfer plate, a spring member, a backside stiffener plate and a spring actuator. The load posts are affixed to the multi-chip module and pass through the printed wiring board. The load transfer plate has a first stiffness. The spring member is disposed adjacent the load transfer plate and has a second stiffness that is less than the first stiffness. The a backside stiffener plate is disposed between the spring member and the printed wiring board and has a third stiffness that is greater than the second stiffness. The spring actuator engages the spring member to apply force to the backside stiffener plate, causing the substrate, the interposer and the printed wiring board to be held in contact.

Claims14

Dependent claims

An apparatus for applying force to a multi-chip module having a substrate, a printed wiring board having a first side and an opposite second side and an interposer, that facilitates electrical contact between the substrate and the printed wiring board through the interposer, the multi-chip module and the interposer being disposed on the first side of the printed wiring board, the apparatus comprising:

a. a plurality of elongated spaced-apart load posts, each load post affixed to the multi-chip module, that pass through a plurality of post holes defined by the printed wiring board from the first side to the second side, each load post having a proximal end affixed to the multi-chip module and an opposite distal end that defines an engagement surface;
b. a load transfer plate, disposed opposite the multi-chip module and spaced apart from the second side of the printed wiring board, the load transfer plate defining a plurality of openings through which the distal ends of each of the plurality of load posts pass, each of the plurality of openings shaped so as to be able to engage the engagement surface of the distal end of a corresponding load post, the load transfer plate having a first stiffness;
c. a spring member disposed adjacent the load transfer plate between the load transfer plate and the printed wiring board, the spring member having a second stiffness that is less than the first stiffness;
d. a backside stiffener plate disposed between the spring member and the printed wiring board, the backside stiffener plate having a third stiffness that is greater than the second stiffness;
and
e. a spring actuator, engageable with the spring member so that the spring actuator applies force to the backside stiffener plate, thereby causing the substrate, the interposer and the printed wiring board to be held in contact.

3 more elements

An apparatus for applying force to a multi-chip module having a substrate, the substrate having a substrate thickness tolerance, a printed wiring board having a printed wiring board thickness tolerance, a first side and an opposite second side, and an interposer, that facilitates electrical contact between the substrate and the printed wiring board through the interposer, the interposer having a interposer thickness tolerance, the multi-chip module and the interposer being disposed on the first side of the printed wiring board, the apparatus comprising:

a. a plurality of elongated spaced-apart load posts that pass through a corresponding plurality of openings defined by the printed wiring board from the first side to the second side, each load post having a load post length tolerance, a proximal end affixed to the multi-chip module and an opposite distal end;
b. a spring member disposed on the second side of the printed wiring board and coupled to the distal ends of the load posts;
and
c. a spring actuator, having a actuator length tolerance, engageable with the spring member so that the actuator applies force to the printed wiring board, to cause a deflection of the spring member in an amount of at least eight times a total stacked tolerance, the total stacked tolerance including the sum of the substrate thickness tolerance, the interposer thickness tolerance, the printed wiring board thickness tolerance, the load post length tolerance, and the actuator length tolerance, thereby causing the substrate, the interposer and the printed wiring board to be held in electrical contact.

1 more element

Dependencies are inferred from the claim text.