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Support Means for Isolating Thermal Device Mass Effects on LGA Interconnections Disclosure Number: IPCOM000015669D
Original Publication Date: 2002-Dec-11
Included in the Prior Art Database: 2003-Jun-20

Publishing Venue



The ever-increasing utilization of Land Grid Array (LGA) connectors has posed a unique difficulty when attempting to isolate the mass effects of thermal devices from the connector's interface. The following approach details a means in which these effects are mitigated for the T-Rex zSeries machine via the application of supporting brackets bars that rigidly mounted to the card's stiffener. Figure 1 shows an assembled view of the application with the thermal device (i.e., the Evaporator/Heat Sink) attached to the MCM and supported by the heat sink (HS) support brackets and bars. Figure 2 details an exploded view of the interconnect hardware including how the brackets attach directly to the card's stiffener and how the bars attach to the brackets. Figures 3 details the specific area incorporated on the thermal device to which the bars contact. Note, the bar's length and the thermal device's mating undercut are tightly controlled to facilitate a snug assembly fit. In addition, the bar contains both a captive threaded portion (to allow one piece handling of the bar and its two screws) and slots to allow the screws to float in respect to the bar once they are advanced into the bracket. Once assembled (with the fastener's torqued), the dynamic forces imposed by the thermal device on the interconnect during shipping shock vibration are now transmitted to the card's stiffener rather than the module's interconnect thus improving the connector's reliability. Lastly, Figure 4 details a recent design enhancement incorporated to provide additional support. In this case, the bars have been revised to include two pressed dowel pins. During assembly to the bracket, these engage in tightly controlled machined slots in the Evaporator/Heat Sink base. The addition of this feature has enhanced the resistance to motion in the direction perpendicular to the bracket/bar. The S&V tests and Pressure Sensitive Film analysis have proved that this invention works and it has unique advantage that it can supports heavy heatsink that can not otherwise be achieved. 1 Evaporator/Heat Sink