Here is the abstract you requested from the Thermal_2008 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Thermal Characterization of a Half mPCI Express Card and Associated Devices|
|Keywords: PCI express, thermals, WiMAX|
|In this paper, thermal characterization using simulations of a half mini PCI express card (HMC) with associated radio and MAC (memory access card) devices in a notebook (WiFi, WIMAX enabled) environment, and inside a JEDEC thermal cycling chamber is completed. Notebook case, motherboard with CPU (central processing unit), HMC parallel to the motherboard and associated device-packages are simulated. A comprehensive parametric study for thermal performance enhancement is completed. Transient temperatures during power on of a selected package card configuration are presented. A mini PCI express card (30x52m) enables wireless connectivity inside ubiquitous notebooks. Double-sided half-mini card is the reduced form factor for commonly used single sided minicard (PCI express) in WiFi, WIMAX applications inside notebooks. The HMC form factor provides obvious cost benefits and reduced foot print on the CPU motherboard. This card form factor reduction necessitates package size reduction as well. However with increasing bandwidth and transfer rate requirements for online audio/video streaming the I/O count and power requirements are increasing. System designers also want the flexibility of attaching wireless cards on the bottom/backside of the motherboard facing gravity down that has negligible air flow. Also there is a RF shield covering the radio die side of the HMC for preventing interference that blocks any surrounding air flow. The electrical routability within space constraints in the half mini card dictates that the QFN2 and PBGA packages be placed exactly opposite to each other with a significant overlap in the footprint. This overlap causes heating of the opposite sides of the HMC and thereby not allowing heat removal mechanism from opposite sides. This poses thermal challenges of keeping thermal junction temperatures below their target limits in products. Several thermal enhancement areas are analyzed and discussed.|
|Raj Bahadur, Packaging Engineer