A Method Of Calculating Thermal Diffusivity And Conductivity For Irregularly Shaped Specimens In Laser Flash Analysis

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Abstract

The Low Temperature Joining Technique (LTJT) using silver compounds enables to significantly increase the thermal conductivity between joined elements, which is much higher than for soldered joints. However, it also makes difficult to measure the thermal conductivity of the joint. The Laser Flash Analysis (LFA) is a non-intrusive method of measuring the temperature rise of one surface of a specimen after excitation with a laser pulse of its other surface. The main limitation of the LFA method is its standard computer software, which assumes the dimensions of a bonded component to be similar to those of the substrate, because it uses the standard Parker’s formula dedicated for one-dimensional heat flow. In the paper a special design of measured specimen was proposed, consisting of two copper plates of different size joined with the sintered silver layer. It was shown that heat properties of these specimens can also be measured after modifying the LFA method. The authors adapted these specimens by masking the false heat signal sourced from the uncovered plate area. Another adaptation was introducing a correcting factor of the heat travel distance, which was calculated with heat-flow simulations and placed into the Parker’s formula. The heat-flow simulated data were compared with the real LFA measurement results, which enabled estimation of the joint properties, e.g. its porosity.

[1] Baba, T., Ono, A. (2001). Improvement of the laser flash method to reduce uncertainty in thermal diffusivity measurements. Meas. Sci. Technol., 12, 2046.

[2] Parker, W.J., Jenkins, R.J., Butler, C.P., Abbott, G.L. (1961). Flash Method of Determining Thermal Diffusivity, Heat Capacity, and Thermal Conductivity. J. Appl. Phys., 32, 1679.

[3] Carslaw, H.S., Jaeger, J.C. (1959). Conduction of Heat in Solids. New York: Oxford University Press.

[4] Campbell, R.C., Smith, S.E., Dietz, R.L. (1999). Measurements of adhesive bondline effective thermal conductivity and thermal resistance using the laser flash method. Semiconductor Thermal Measurement and Management Symposium, 15th Annual IEEE.

[5] Coquard, R., Panel, B. (2009). Adaptation of the FLASH method to the measurement of the thermal conductivity of liquids or pasty materials. International Journal of Thermal Sciences, 48(4), 747–760.

[6] Wang, T., Zhao, M., Chen, X., Lu, G.Q., Ngo, K., Luo, S. (2012). Shrinkage and Sintering Behavior of a Low-Temperature Sinterable Nanosilver Die-Attach Paste. Journal of Electronic Materials, 41(9).

[7] Jakubowska, M., Jarosz, M., Kiełbasiński, K., Szałapak, J., Młożniak, A. (2012). Thick-film screen printable pastes based on silver powders for die-attachment applications. Proc. IMAPS-CPMT, Poland, 256−268.

[8] Mina, S., Blumm, J., Lindemann, A. (2007). A new laser flash system for measurement of the thermophysical properties. Thermochimica Acta, 455(1–2), 46–49.

[9] Chudzik, S., Minkina, W. (2011). An idea of a measurement system for determining thermal parameters of heat insulation Mmaterials. Metrol. Meas. Syst., 17(2), 261–274.

[10] Frankiewicz, M., Gołda, A., Kos, A. (2014). Investigation of heat transfer in integrated circuits. Metrol. Meas. Syst., 21(1), 111–120.

Metrology and Measurement Systems

The Journal of Committee on Metrology and Scientific Instrumentation of Polish Academy of Sciences

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IMPACT FACTOR 2016: 1.598

CiteScore 2016: 1.58

SCImago Journal Rank (SJR) 2016: 0.460
Source Normalized Impact per Paper (SNIP) 2016: 1.228

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