Thermal interface materials (TIMs) are an important component in electronic packaging, and there is a concerted effort to understand their reliability when used under various environmental load conditions. Previous researchers have investigated gap fillers and other types of TIMs to understand their performance degradation under loading conditions such as thermal cycling and thermal aging. Most of the study in the literature focuses on studying the changes in thermal properties, and there is a lack of understanding when it comes to studying the mechanical behavior of TIMs. Degradation of mechanical properties is the cause for the loss in thermal performance and is critical during TIM selection process. Moreover, mechanical properties such as modulus and coefficient of thermal expansion (CTE) are critical to assess performance of TIMs using finite element analysis (FEA) and potentially save time and money in the evaluation and selection process. Due to the very soft nature of TIMs, sample preparation is a challenging part of material characterization. In this paper, commercially available TIMs are studied using testing methods such as thermomechanical analyzer (TMA), dynamic mechanical analyzer (DMA), and Fourier infrared spectroscopy (FTIR). These methods are used to characterize the material properties and study the changes in properties due to aging. In this work, the followings are presented: impact of filler content on the mechanical properties, sample preparation method for curable TIM materials with specified thicknesses, and impact of thermal aging on mechanical properties.
Contamination due to the use of airside economizer has become a major issue that cost companies revenue. This issue will continue to rise as server components become smaller, densely packed, and as companies move into more polluted environments. Contaminants with small particles less than 10 μm are not noticeable; yet, these particles are most likely to get to areas where they can cause damage. Dust from different sources and suspended in air settles on surfaces of electrical components. The dust mainly contains two components: salts and metallic particles. The salts may be neutral or corrosive and the nature of the salt depends on the deliquescent humidity. For metallic particles, surveys are performed in various data centers in order to determine the limits in terms of weight per unit area and particle size distribution. It is necessary to first identify those contaminants that directly affect the information technology (IT) equipment in the data center. In this research, a real-world data center utilizing airside economization in an ANSI/ISA classified G2 environment was chosen for the study. Servers were removed and qualitative study of cumulative corrosion damage was carried out. The particulate contaminants were collected from different locations of a server and material characterization was performed using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and Fourier transform infrared spectroscopy (FTIR). The analysis from these results helps to explain the impact of the contaminants on IT equipment reliability.
Immersion cooling is highly efficient thermal management technique and can potentially be used for thermal management of high-density data. However, to use this as a viable cooling technique, the effect of dielectric coolants on the reliability of server components needs to be evaluated. Previous work reported contradicting findings for Young’s modulus of PCBs, providing motivation for this work. This study focuses on effect of immersion cooling on the mechanical properties of printed circuit board (PCB) and its impact on reliability of electronic packages. Changes in thermo-mechanical properties like Young’s modulus (E), Glass transition temperature (Tg), of PCB and its layers due to aging in dielectric coolant are studied. Two types of PCBs using different material namely 370HR and 185HR are studied. To characterize Young’s modulus and Tg dynamic mechanical analyzer (DMA) is used. Major finding is Young’s modulus is decreasing for PCBs after immersion in dielectric coolant which is likely to increase reliability of electronics package.
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