Skip to main content
SpringerLink
Log in

Thermal Testing of LEDs

  • Chapter
  • First Online:
Thermal Management for LED Applications

Part of the book series: Solid State Lighting Technology and Application Series ((SSLTA,volume 2))

Abstract

In this chapter, after a generic discussion of thermal testing techniques used to characterize packaged semiconductor devices; the latest practical test methods widespread in thermal testing of LED components and SSL luminaires are discussed. Thus, the focus is on the latest, power semiconductor and LED-specific test procedures, environments and thermal metrics—all derived from the classical JEDEC JESD51 family of testing standards. Detailed discussion is devoted to the transient extension of the so-called static test method and the differential measurement principle in its practical realization.

Different representations of the thermal impedance are presented starting from the classical Z th (t) functions ending with the so-called structure functions. These are discussed in depth because they became the de facto standard in laboratory testing of thermal properties of LED components, in reliability analysis and in quality assurance at leading LED manufacturers. The basic concepts are introduced through practical examples.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Log in via an institution
Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 129.00
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD 169.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info
Hardcover Book
USD 169.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Notes

  1. 1.

    Some of these topics will be discussed later in this chapter and many more in Chap. 11, but their detailed treatment is beyond the scope of this book.

  2. 2.

    The mentioned cities span over a large surface while distance is defined between two points. The question is: are there some points in these cities which are characteristic for the real target of the distance measurement and where are they located? We face similar questions in the thermal testing of semiconductor devices. To which point of the active semiconductor we assign the “junction temperature”? Resistance (strictly speaking) is defined between two nodes of a graph. Which are the distinct points between which we define the thermal resistance? See Chap. 6 for further details on these issues.

  3. 3.

    Measurement waveforms for the “static” test methods are depicted in Fig. 6.20 of Chap. 6; (see also [6] and [7]). A concise summary of thermal measurement of diodes is given in [7,  – – 9]. A more detailed analysis is provided in Sect. 4.3.6.

  4. 4.

    The junction-to-test point thermal characterization parameter is a thermal metric, which can help relate junction temperatures to test point temperatures. Discussion of such simple tests is not the main target of this chapter.

  5. 5.

    The effect of the series resistance is discussed in detail in Chaps. 2 and 6 and in papers Farkas, G. [15, Farkas, G. 16].

  6. 6.

    Voltage and current notations correspond to the notations used the JESD51-5x series of standards, see also Chap. 6.

  7. 7.

    This extension was first defined in details in the JEDEC JESD 51-14 standard [13]. This proposes a transient method for the measurement of the junction-to-case thermal resistance of power semiconductor device packages with a single heat flow path and with an exposed cooling surface—such as power LED packages. JEDEC JESD 51-14 also prefers the cooling mode transient measurement for diodes since the error introduced by the slightly changing power after switching is negligible in this case (as we also pointed out by a numerical example). The most recent LED thermal testing standard JESD51-51 [6] also recommends the cooling mode measurement if the task is to measure the real Z th (t) thermal impedance of an LED package.

  8. 8.

    See also Chap. 2 on the physical basics of LEDs.

  9. 9.

    In electronics, the impedance is interpreted in the frequency domain, not in the time domain as a step-response function. In Sect. 6.1.4.1 of Chap. 6, the thermal resistance concept is generalized to thermal impedances.

  10. 10.

    See Sect 6.5.2.2 of Chap. 6 for an overview of LED multidomain modeling.

  11. 11.

    The concept of cumulative resistance and cumulative capacitance and the concept of the CΣ(RΣ) function were first introduced by Protonotarios and Wing in their fundamental papers about the theory of nonuniform (electrical) RC lines. In the first part, Protonotarios, E. N. [22] they used this function for simplifying the telegraphists’ equations when used in the synthesis of nonuniform RC lines.

  12. 12.

    Driving point means that heating and measuring the temperature response takes place at the same physical location. See also Sect. 6.1.4.2 of Chap. 6.

  13. 13.

    Achieving a time resolution higher than 20 points per decade may require unaffordable simulation resources while measuring a thermal transient with about 200 or 400 points per decade resolution is not a problem with the transient extension of the JESD51-1 “static” test method.

  14. 14.

    This problem can be overcome by using special math libraries in the implementation, which provide any number of digits both for the exponent and for the mantissa.

  15. 15.

    In many cases, the adjective “cumulative” is neglected and the CSF is simply called the structure function.

  16. 16.

    The analysis technique based on changing C th /R th ratio in the structure function was first suggested by Rencz et al. [29] for the study of die attach voiding and for TIM quality assessment.

  17. 17.

    In this particular case, about 1.5 % loss can be attributed directly to the increased thermal resistance.

  18. 18.

    Measurement and simulation results by courtesy of Vass-Várnai and Bornoff.

  19. 19.

    These ballasts usually hamper thermal testing and thus need to be bypassed for the sake of this test.

References

  1. Lasance C J M, den Hertog D., Stehouwer P. (1999) Creation and evaluation of compact models for thermal characterisation using dedicated optimisation software. In: Proceedings of the 15th IEEE Semiconductor Thermal Meas-urement and Management Symposium (SEMI-THERM’99), San Diego, USA, 9-11 March, pp 189–200

    Google Scholar 

  2. Farkas G, Poppe A, Kollár E, Stehouwer P (2003) Dynamic Compact Models of Cooling Mounts for Fast Board Level Design. In: Proceedings of the 19th IEEE Semiconductor Thermal Measurement and Management Symposium (SEMI-THERM’03). San Jose, 11–13 March 2003. pp. 255–262.

    Google Scholar 

  3. Szabó P, Poppe A, Rencz M Studies on the possibilities of in-line die at-tach characterization of semiconductor devices. In: Proceedings of the 9th Electronics Packaging Technology Conference (EPTC’07), 10-12 December 2007, Singapore, pp. 779–784 (ISBN: 978-1-4244-1324–9)

    Google Scholar 

  4. Szabó P, Rencz M, Farkas G, Poppe A. Short time die attach characteri-zation of LEDs for in-line testing application. In: Proceedings of the 8th Electronics Packaging Technology Conference (EPTC’06): Volume One. Singapore, 6-8 December 2008, pp. 360–366 (ISBN: 1-4244-0664–1)

    Google Scholar 

  5. JEDEC Standard JESD51-1. Integrated Circuits Thermal Measurement Method – Electrical Test Method (Single Semiconductor Device). www.jedec.org/sites/default/files/docs/jesd51-1.pdf (December 1995)

  6. JEDEC Standard JESD51-51 Implementation of the Electrical Test Method for the Measurement of the Real Thermal Resistance and Impedance of Light-emitting Diodes with Exposed Cooling Surface. www.jedec.org/sites/default/files/docs/JESD51-51.pdf. (April 2012)

  7. Siegal B. An_Introduction_to_Diode_Thermal_Measurements, www.thermengr.net/An_Introduction_to_Diode_Thermal_Measurements6.pdf

  8. Siegal B (1978) Measuring thermal resistance is the key to a cool semiconductor. Electronics 51:121–126

    Google Scholar 

  9. Sofia J W (1995) Analysis of thermal transient data with synthesized dynamic models for semi-conductor devices. IEEE Trans Comp Pack Manuf 18(1):39–47

    Article  Google Scholar 

  10. JEDEC Standard JESD51. Methodology for the Thermal Measurement of Component Packages (Single Semiconductor Devices). This is the overview document for the JESD51- series of specifications. www.jedec.org/sites/default/files/docs/Jesd51.pdf. (December 1995)

  11. Guenin B Update on Thermal Standards Work by JC15.1. www.ewh.ieee.org/soc/cpmt/presentations/cpmt0303a.pdf

  12. Guenin B Update on JEDEC Thermal Standards. Electronics Cooling Vol.18. www.electronics-cooling.com/2012/09/update-on-jedec-thermal-standards. 17 September 2012

  13. JEDEC Standard JESD51–14 Transient Dual Interface Test Method for the Measurement of Thermal Resistance Junction-to-Case of Semiconductor De-vices with Heat Flow through a Single Path.www.jedec.org/download/search/jesd51-14.pdf. (November 2010)

  14. JEDEC Standard JESD51–50 Overview of Methodologies for the Thermal Measurement of Single- and Multi-Chip, Single- and Multi-PN Junction Light-Emitting Diodes (LEDs). www.jedec.org/sites/default/files/docs/jesd51-50.pdf. (April 2012)

  15. Farkas G, van Voorst Vader Q, Poppe A, Bognár Gy (2005) Thermal Investigation of High Power Optical Devices by Transient Testing. IEEE Trans Comp Pack Techn 28(1):45–50

    Article  Google Scholar 

  16. Farkas G et al Electric and Thermal Transient Effects in High Power Optical Devices” Proceedings of the 20th IEEE Semiconductor Thermal Measurement and Management Symposium (SEMI-THERM’04). San Jose, March 2004, pp. 168–176.

    Google Scholar 

  17. Rencz M, Székely V (2004) Studies on the nonlinearity effects in dynamic compact model generation of packages. IEEE Trans Comp Pack Techn 27(1):124–130

    Article  Google Scholar 

  18. Poppe A, Molnár G, Temesvölgyi T Temperature dependent thermal re-sistance in power LED assemblies and a way to cope with it. In: Proceedings of the 26th IEEE Semiconductor Thermal Measurement and Management Symposium (SEMI-THERM’10), 21–25 February 2010, Santa Clara, USA, pp. 283-288. (ISBN: 978-1-4244-6458–1)

    Google Scholar 

  19. Székely V (1991) On the representation of infinite-length distributed RC one-ports. IEEE Trans Circuit Sys 38(7):711–719

    Article  Google Scholar 

  20. Székely V, Rencz M (2000) Thermal Dynamics and the Time Constant Domain. IEEE Trans Comp and Pack Techn 23(3):687–594

    Google Scholar 

  21. Székely V, Bien T V (1988) Fine structure of heat flow path in semiconductor devices: a measurement and identification method. Solid-State Electronics 31(9):1363–1368

    Article  Google Scholar 

  22. Protonotarios E N, Wing O (1967) Theory of nonuniform RC Lines, part I: analytic properties and realizability conditions in the frequency domain. IEEE Trans Circuit Theory 14(1):2–12

    Article  Google Scholar 

  23. Székely V (1998) Identification of RC Networks by deconvolution: Chances and Limits. IEEE Trans Circuits and Sys I - Fundamental Theory and App 45(3):244–258

    Google Scholar 

  24. Székely V, Rencz M, Poppe A, Courtois B (2001) THERMODEL: a tool for thermal model generation, and application for MEMS. Analog Integrat Circuit Signal Process 29(1–2):49–59

    Article  Google Scholar 

  25. Rencz M, Poppe A, Kollár E, Ress S, Székely V (2005) Increasing the Accuracy of Structure Function Based Thermal Material Parameter Measurements. IEEE Trans Comp and Pack Techn 28(1):51–57

    Article  Google Scholar 

  26. Poppe A, Siegal B, Farkas G Issues of Thermal Testing of AC LEDs. Proceedings of the 27th IEEE Semiconductor Thermal Measurement and Management Symposium (SEMI-THERM’11), San Jose, USA, 20–24 March 2011, pp 297–304

    Google Scholar 

  27. Vermeersch B (2009) Thermal AC modelling, simulation and experimental analysis of microelectronic structures including nanoscale and high-speed effects. PhD Tesis, D/2009/10.500/24, University of Ghent, Ghent, Bel-gium. http://lib.ugent.be/fulltxt/RUG01/001/330/941/RUG01-001330941_2010_0001_AC.pdf

  28. Poppe A, Molnár G, Csuti P, Szabó F, Schanda J Ageing of LEDs: A Comprehensive Study Based on the LM80 Standard and Thermal Transient Measurements. In: CIE 27th Session-Proceedings, CIE 197:2011: (Volume1, Part 1–2). 10-15 July 2011, Sun City, South Africa, Vienna: CIE, pp. 467–477

    Google Scholar 

  29. Rencz M, Székely V, Morelli A, Villa C (March 2002) Determining Partial Thermal Resistances with Transient Measurements, and Using the Method to Detect Die Attach Discontinuities. In: Proceedings of the 18th IEEE Semiconductor Thermal Measurement and Management Symposium (SEMI-THERM’02), March 12–14, 2002, San Jose, USA, pp. 15–20

    Google Scholar 

  30. Steffens O, Szabó P, Lenz M, Farkas G (March 2005) Thermal transient characterization methodology for single-chip and stacked structures. In: Proceedings of the 21st IEEE Semiconductor Thermal Measurement and Management Sym-posium (SEMI-THERM’05), 15–17 March 2005, San Jose, USA, pp 313–321

    Google Scholar 

  31. Schweitzer D, Pape H, Chen L, Kutscherauer R, Walder M (March 2011) Transient dual interface measurement—A new JEDEC standard for the measurement of the junction-to-case thermal resistance. In: Proceedings of the 27th IEEE Semiconductor Thermal Measurement and Management Symposium (SEMI-THERM’11), 20–24 March 2011, San Jose, USA, pp 222–229

    Google Scholar 

  32. Pape H, Schweitzer D, Chen L, Kutscherauer R, Walder M (2011) Development of a standard for transient measurement of junction-to-case thermal re-sistance. In: Proceedings of the 12th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelec-tronics and Microsystems (EuroSimE’11), 2011, pp 1/8–8/8

    Google Scholar 

  33. Schweitzer D, Pape H, Chen L (2008) Transient Measurement of the Junction-to-Case thermal resistance using structure functions: chances and limits. In: Proceedings of the 24th IEEE Semiconductor Thermal Measurement and Management Symposium (SEMI-THERM’08), 16–20 March 2008, San Jose, USA, pp 193–199

    Google Scholar 

  34. Schweitzer D (2008) Transient dual interface measurement of the Rth-JC of power packages. In: Proceedings of the 14th International Workshop on THERMal INvestigation of ICs and Systems (THERMINIC’08), 24–26 September 2008, Rome, Italy, pp 14–19

    Google Scholar 

  35. Schweitzer D, Pape H, Kutscherauer R, Walder M (2009) How to evaluate transient dual interface measurements of the Rth-JC of power packages. In: Proceedings of the 25th IEEE Semiconductor Thermal Measurement and Management Symposium (SEMI-THERM’09), 15–19 March 2009, San Jose, USA, pp 172–179

    Google Scholar 

  36. Müller S, Zahner T, Singer F, Schrag G, Wachutka G (2011) Evaluation of thermal transient characterization methodologies for HighüPower LED applications. In: Proceedings of the 17th International Workshop on THERMal INvestigations of ICs and Systems (THERMINIC’11), 27–29 September 2011, Paris, France, pp 104–109

    Google Scholar 

  37. ASTM Standard D 5470, 2012, Standard Test Method for Thermal Trans-mission Properties of Thin Thermally Conductive Solid Electrical Insulation Materials. ASTM International, West Conshohocken PA USA, 2012, DOI: 10.1520/D5470-12; www.astm.org

  38. Mentor Graphics’ DynTIM tester webpage: www.mentor.com/products/mechanical/products/dyntim

  39. Mentor Graphics’ T3Ster thermal transient tester webpage: www.mentor.com/products/mechanical/products/t3ster

  40. Vass-Várnai A, Székely V, Sárkány Z, Rencz M (2011) New level of accuracy in TIM measurements. In: Proceedings of the 27th IEEE Semiconductor Thermal Measurement and Management Symposium (SEMI-THERM’11), 20–24 March 2011, San Jose, USA, pp 317–324

    Google Scholar 

  41. Vass-Várnai A, Sárkány Z, Rencz M (2012) Characterization method for thermal interface materials imitating an in-situ environment. Microelectronics J 43(9):661–668

    Article  Google Scholar 

  42. ANSI/IESNA IES-LM-80-08 Standard (2009) Approved Method for Measuring Lumen Maintenance of LED Light Sources. ISBN 978-0-87995-227–3

    Google Scholar 

  43. Hu J, Yang L, Shin M W (2005) Mechanism and Thermal Effect of Delamination in Light Emitting Diode Packages. In: Proceedings of the 11th International Workshop on THERMal INvestigations of ICs and Systems (THERMINIC’05), 28–30 September 2005, Belgirate, Italy, pp 249–254

    Google Scholar 

  44. Hu J, Yang L, Shin M W (2007) Mechanism and Thermal Effect of Delamination in Light-Emitting Diode Packages. Microelectronics Journal 38:157–163

    Article  Google Scholar 

  45. Vass-Várnai A, Sárkány Z, Rencz M (2009) Reliability Testing of TIM Materials with thermal transient measurements. In: Proceedings of the 11th Electronics Packaging Technology Conference (EPTC’09), 9–11 December 2009, Singapore, pp 823–827

    Google Scholar 

  46. Pape H, Schweitzer D, Janssen J H J, Morelli A, Villa C M (2004) Thermal transient modeling and experimental validation in the European project PROFIT. IEEE Trans Comp and Pack Techn 27(3):530–538

    Article  Google Scholar 

  47. Vass Várnai A, Bornoff R, Sárkány Z, Ress S, Rencz M (2011) Measurement Based Compact Thermal Model Creation-Accurate Approach to Neglect Inaccurate TIM Conductivity Data. In: Proceedings of the 13th Electronics Packaging Technology Conference (EPCT’11), 7–9 December 2011, Singapore, pp 67–72

    Google Scholar 

  48. Poppe A, Vass-Varnai A, Farkas G, Rencz M (2008) Package characterization: simulations or measurements?. In: Proceedings of the 10th Electronics Pack-aging Technology Conference (EPTC’08). 9–12 December 2008, Singapore, pp 155–160. Paper A6.4.

    Google Scholar 

  49. Yen H-H, Kuo H-C, Yeh W-Y (2008) Characteristics of Single-Chip GaN-Based Alternating Current Light-Emitting Diode. Japanese Journal of Applied Physics 47: 8808–8810

    Article  Google Scholar 

  50. Chou P-T, Yeh W-Y, Lin M-T, Tai S-C, Yen H-H (2009) Development of On-chip AC LED Lighting Technology at ITRI. Proc. of the 2009 CIE Midterm Conference, Light and Lighting, Budapest, Hungary

    Google Scholar 

  51. Cho J, Jung J, Chae J H, Kim H, Kim H, Lee J W, Yoon S, Sone C, Jang T, Park Y, Yoon E (2007) Alternating-current light emit-ting diodes with a diode bridge circuitry. Japanese J Appl Phys 46:1194–1196

    Article  Google Scholar 

  52. Zong Y, Chou P -T, Lin M -T, Ohno Y (2009) Practical method for measure-ment of AC-driven LEDs at a given junction temperature by using active heat sinks. In: SPIE Proceedings 7422, Ninth International Conference on Solid State Lighting (eds.: Tsunemasa Taguchi, Ian T. Ferguson, Christoph Hoelen, Jianzhong Jiao), 2 August 2009, San Diego, CA, USA, p 742208

    Google Scholar 

  53. Y. Liu Y, Jayawardena A , Klein T R, Narendran N (2010) Estimating the junction temperature of AC LEDs. In: SPIE Proceedings 7784, Tenth International Conference on Solid State Lighting (eds.: I. Ferguson; M. H. Kane; N. Nar-endran; T. Taguchi), 1 August 2010, San Diego, CA, USA, p 778409

    Google Scholar 

  54. Zong Y, Ohno Y (2008) New practical method for measurement of high-power LEDs. In: Proceedings of the CIE Expert Symposium 2008 on Ad-vances in Photometry and Colorimetry, CIE x033:2008, pp 102–106

    Google Scholar 

  55. Poppe A, Farkas G, Temesvölgyi T, Katona B, Molnár G (2010) Thermal Impedance of AC LED-s. In: Proceedings of the 16th International Workshop on THERMal INvestigation of ICs and Systems (THERMINIC’10). 6–8 October 2010, Barcelona, Spain, pp 127–132

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Mentor Graphics MAD MicReD unit, Infopark D, Gábor Dénes utca 2, 1117, Budapest, Hungary

    Gábor Farkas & András Poppe

Authors
  1. Gábor Farkas
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. András Poppe
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Gábor Farkas .

Editor information

Editors and Affiliations

  1. Philips Research Emeritus, Nuenen, The Netherlands

    Clemens J.M. Lasance

  2. MicReD Unit Budapest XI, Infopark D, Mentor Graphics Mechanical Analysis Divi, Budapest XI, Infopark D, Hungary

    András Poppe

Rights and permissions

Reprints and permissions

Copyright information

© 2014 Springer Science+Business Media New York

About this chapter

Cite this chapter

Farkas, G., Poppe, A. (2014). Thermal Testing of LEDs. In: Lasance, C., Poppe, A. (eds) Thermal Management for LED Applications. Solid State Lighting Technology and Application Series, vol 2. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-5091-7_4

Download citation

  • DOI: https://doi.org/10.1007/978-1-4614-5091-7_4

  • Published:

  • Publisher Name: Springer, New York, NY

  • Print ISBN: 978-1-4614-5090-0

  • Online ISBN: 978-1-4614-5091-7

  • eBook Packages: EngineeringEngineering (R0)

Publish with us

Policies and ethics

Search

Navigation