M. Buller

Bio: M. Buller is an academic researcher from IBM. The author has contributed to research in topics: Thermal transmittance & Operating temperature. The author has an hindex of 2, co-authored 2 publications receiving 24 citations.

Thermal Transients in Electronic Packages

Abstract: The use of a transient analysis to accurately characterize the operating temperature of electronic modules should result in lower temperature estimates. This will reflect increases in both the reliability estimates and the performance specifications. An accurate cooling analysis would also enhance the projected product life or reduce the system cooling requirements. Simplified expressions have been obtained for the calculation of chip and module thermal transients which, when superimposed, characterize the total package time/temperature response. Empirical data demonstrate the validity of the assumptions used to obtain these expressions. The thermal time constants are also presented in graphical form using parameters easily obtainable by the design engineer (e.g., cooling air velocity, steadystate temperature differences, and module location) so that order of magnitude assessments can be made.

Thermal Characteristics of Horizontally Oriented Electronic Components in an Enclosed Environment

Abstract: A closed-form expression is derived to correlate experimental data relating the thermal characteristics of electronic hardware in an enclosed system. Due to the geometric constraints sometimes imposed in small system architecture, the analysis concerns itself only with the effect of horizontal orientation. Variations in the enclosed volume create changes in the buoyancy-induced flows which affect the thermal characteristics of an adiabatic fiat plate. Data from the fiat plate study are correlated against additional data using a typical memory card populated with area-pin array modules. The results provide a technique to obtain the surface heat transfer coefficient and thus the natural convection component of the total heat load. Radiation losses, which play a major role in this type of system, are also discussed. A combination of these two components yield the maximum power dissipation allowable to maintain a specified electronic component temperature within an enclosed system with known bulk air temperature limits.

Thermal Control of Electronic Equipment and Devices

Abstract: Publisher Summary Thermal control of electronic components has one principal objective, to maintain relatively constant component temperature equal to or below the manufacturer's maximum specified service temperature, typically between 85 and 100°C. It is noted that even a single component operating 10°C beyond this temperature can reduce the reliability of certain systems by as much as 50%. Therefore, it is important for the new thermal control schemes to be capable of eliminating hot spots within the electronic devices, removing heat from these devices and dissipating this heat to the surrounding environment. Several strategies have developed over the years for controlling and removing the heat generated in multichip modules, which include advanced air-cooling schemes, direct cooling, and miniature thermosyphons or free-falling liquid films. The chapter summarizes analytical, numerical, and experimental work in literature, in order to facilitate the improvement of existing schemes and provide a basis for the development of new ones. The chapter focuses on investigations performed over the past decade and includes information on the thermal control of semiconductor devices, modules, and total systems.

An Overview of Non-Destructive Testing Methods for Integrated Circuit Packaging Inspection.

Abstract: The article provides a review of the state-of-art non-destructive testing (NDT) methods used for evaluation of integrated circuit (IC) packaging. The review identifies various types of the defects and the capabilities of most common NDT methods employed for defect detection. The main aim of this paper is to provide a detailed review on the common NDT methods for IC packaging addressing their principles of operation, advantages, limitations and suggestions for improvement. The current methods such as, X-ray, scanning acoustic microscopy (SAM), infrared thermography (IRT), magnetic current imaging (MCI) and surface acoustic waves (SAW) are explicitly reviewed. The uniqueness of the paper lies in comprehensive comparison of the current NDT methods, recommendations for the improvements, and introduction of new candidate NDT technologies, which can be adopted for IC packaging.

Thermal design rules for electronic components on conducting boards in passively cooled enclosures

Abstract: A better understanding is needed of the approaches and limitations for rejecting heat dissipated from VLSI components mounted on multi-layer printed circuit boards housed in small enclosures, as for example those encountered in small consumer electronics, and, in notebook, laptop, or hand-held personal computers. This paper derives new first order thermal design formulae for determining the peak temperatures of sources on conducting substrates, and for determining the thermal "zone of influence" or "footprint" associated with a component on a board. A one-dimensional thin board radial fin approach is used with inclusion of a circular source to represent the heat dissipating component. Exact solutions are presented for sources at the center, edge, and corner of a rectangular board. The results are compared with with both 2-d and 3-d calculations for rectangular sources on a board using the finite element method. Excellent agreement is found in predicting the maximum temperature, with maximum differences of order 10%. Simple algebraic design formulae, useful for rapid estimation, are derived from the complete solutions by taking advantage of the asymptotic behavior at small and large values of the board parameter, m. An unambiguous thermal footprint radius is defined in terms of the tangent line at the inflection point of the temperature profile. Parametric studies show that the radius corresponds to the point at which the board temperature drops to roughly 18% of its peak temperature, for all variations of board thickness and conductivity of practical interest. The simple analytical model is used to predict the temperatures on a populated board, using a linear superposition principle, and it is found to be in good agreement with experimental results for boards with multiple heat sources. >

Thermal analysis of integrated circuit chips using a thermographic imaging technique

Abstract: This paper presents the analysis of the thermal gradients on the substrate of an integrated-circuit chip (telephone line interface chip) using thermographic imaging techniques. After taking the chip thermal image using a thermal camera and doing temperature calibration, an isothermal contour map of the chip region is drawn by digital image-processing techniques proposed in this paper. By overlaying the layout mask on the isothermal contour map of the chip region, each region of the chip is easily identified. This information is of great assistance to the designer while laying out the components on the chip. >