Patent Application
20050243521
This invention relates generally to mounting integrated circuits on circuit boards such as motherboards.
Conventionally, packaged integrated circuits, such as a processor, may be provided through a socket for securement to a printed circuit board such as a motherboard. There are a variety of different ways of making connections between the integrated circuit and the board. One such way is a land grid array, in which surface mount techniques are utilized to connect the socket to the printed circuit board. A load plate may be utilized to force the integrated circuit into tight electrical connection to the socket.
One problem that arises is that the force applied through the load plate may result in relative horizontal movement in the plane of the socket between the load plate and an integral heat spreader provided with the integrated circuit package. This may cause the integrated circuit package to be seated improperly within the socket body. Improper seating may result in open circuits.
Thus, there is a need for better ways to secure packaged integrated circuits to sockets.
Referring to
The load plate 12 may be cammed downwardly to get good electrical connection between contacts on the integrated circuit 24 and the socket 34 by an actuator 16. The actuator 16, in one embodiment, may be part of an integral L-shaped bar 14, having a curved end that may be latched under a catch 32, in one embodiment, to lock the load plate 12 into engagement with the integrated circuit 24. In particular, the actuator 16 may be rotated counterclockwise around and down as the load lever 14 is rotated within its tubular retainer 20.
Alignment between the load plate 12 and an integral heat spreader 48 may be ensured by downwardly projecting protrusions 42 which engage mating slots 46 in the upper surface of the integral heat spreader 44. When the load plate 12 is a metal stamping, the protrusions 42 may be formed during the stamping process.
Thus, referring to
The packaged integrated circuit 24 may be seated within the integral heat spreader 44. With the load plate 12 clips 22 engaged in the openings 30 in the stiffener 28, the load plate 12 may be rotated counter-clockwise over the integral heat spreader 44. The load lever 14 may be rotated upwardly or counterclockwise from the position shown in
As all of this is happening, the protrusions 42 and mating slots 46 maintain close alignment between the load plate 12 and the integral heat spreader 44, preventing horizontal displacement between those parts and the packaged integrated circuit 24.
Without the alignment features, such as the slots 46 and protrusions 42, the play between the clips 22 and openings 30 permit relative movement between the load plate 12 and the stiffener 28 towards or away from the retainer 20. Depending on the direction of such horizontal displacement, non-uniform pressure is applied to the socket 34 along the line between the openings 30 and retainer 20. This non-uniform pressure may result in poor electrical connections. The provision of the alignment features keeps the load plate 12 centered over the socket 34 enabling the load plate 12 to apply more uniform pressure to the contacts between the integrated circuit 24 and the socket 34.
Thus, referring to
As better shown in
In some embodiments, not only is horizontal movement of the load plate prevented during the socket actuation, reducing the risk of opens caused by improper packaged seating, but the slots 46 in the integral heat spreader 44 may also serve as additional alignment features to ensure that the package 24 is inserted in the right orientation.
While an embodiment is illustrated in which downward protrusions are formed on the load plate and mating slots are formed on the integral heat spreader, other arrangements for alignment features may be utilized as well. For example, the alignment feature on the load plate may be an indentation that receives a protrusion on the integral heat spreader. Other arrangements and orientations of the alignment features may also be possible. Similarly, the number of alignment features may be varied.
While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.
