# Thermal and mechanical analysis of high-power LEDs with ceramic packages

Jianzheng Hu, Lianqiao Yang, Moo Whan Shin

Research output: Contribution to journalArticle

33 Citations (Scopus)

### Abstract

In this paper, we present the thermal and mechanical analysis of high-power light-emitting diodes (LEDs) with ceramic packages. Transient thermal measurements and thermomechanical simulations were performed to study the thermal and mechanical characteristics of ceramic packages. Thermal resistances from the junction to the ambient were decreased from 79.6 to 46.7 $^{\circ}\hbox{C/W}$ by replacing the plastic mold with a ceramic mold for LED packages. Thermomechanical stress induced in the heat-block test was simulated using a finite-element method. Higher level of thermomechanical stress in the chip was found for LEDs with ceramic packages, despite less mismatching coefficients of thermal expansion, compared with that with plastic packages. The thermomechanical-stress components in the direction of the thickness were found to be larger than that in other two directions. The results suggest that the thermal performance of LEDs can be improved by using ceramic packages, but the mounting process of the high-power LEDs with ceramic packages is critically important and should be the reason for causing delaminating interface layers in the packages.

Original language English 4472167 297-303 7 IEEE Transactions on Device and Materials Reliability 8 2 https://doi.org/10.1109/TDMR.2008.920298 Published - 2008 Jun 1

### Fingerprint

Light emitting diodes
Plastic molds
Mountings
Heat resistance
Thermal expansion
Hot Temperature
Plastics
Finite element method
Direction compound

### All Science Journal Classification (ASJC) codes

• Electrical and Electronic Engineering
• Electronic, Optical and Magnetic Materials
• Safety, Risk, Reliability and Quality

### Cite this

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title = "Thermal and mechanical analysis of high-power LEDs with ceramic packages",
abstract = "In this paper, we present the thermal and mechanical analysis of high-power light-emitting diodes (LEDs) with ceramic packages. Transient thermal measurements and thermomechanical simulations were performed to study the thermal and mechanical characteristics of ceramic packages. Thermal resistances from the junction to the ambient were decreased from 79.6 to 46.7 $^{\circ}\hbox{C/W}$ by replacing the plastic mold with a ceramic mold for LED packages. Thermomechanical stress induced in the heat-block test was simulated using a finite-element method. Higher level of thermomechanical stress in the chip was found for LEDs with ceramic packages, despite less mismatching coefficients of thermal expansion, compared with that with plastic packages. The thermomechanical-stress components in the direction of the thickness were found to be larger than that in other two directions. The results suggest that the thermal performance of LEDs can be improved by using ceramic packages, but the mounting process of the high-power LEDs with ceramic packages is critically important and should be the reason for causing delaminating interface layers in the packages.",
author = "Jianzheng Hu and Lianqiao Yang and Shin, {Moo Whan}",
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Thermal and mechanical analysis of high-power LEDs with ceramic packages. / Hu, Jianzheng; Yang, Lianqiao; Shin, Moo Whan.

In: IEEE Transactions on Device and Materials Reliability, Vol. 8, No. 2, 4472167, 01.06.2008, p. 297-303.

Research output: Contribution to journalArticle

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AU - Hu, Jianzheng

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AU - Shin, Moo Whan

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N2 - In this paper, we present the thermal and mechanical analysis of high-power light-emitting diodes (LEDs) with ceramic packages. Transient thermal measurements and thermomechanical simulations were performed to study the thermal and mechanical characteristics of ceramic packages. Thermal resistances from the junction to the ambient were decreased from 79.6 to 46.7 $^{\circ}\hbox{C/W}$ by replacing the plastic mold with a ceramic mold for LED packages. Thermomechanical stress induced in the heat-block test was simulated using a finite-element method. Higher level of thermomechanical stress in the chip was found for LEDs with ceramic packages, despite less mismatching coefficients of thermal expansion, compared with that with plastic packages. The thermomechanical-stress components in the direction of the thickness were found to be larger than that in other two directions. The results suggest that the thermal performance of LEDs can be improved by using ceramic packages, but the mounting process of the high-power LEDs with ceramic packages is critically important and should be the reason for causing delaminating interface layers in the packages.

AB - In this paper, we present the thermal and mechanical analysis of high-power light-emitting diodes (LEDs) with ceramic packages. Transient thermal measurements and thermomechanical simulations were performed to study the thermal and mechanical characteristics of ceramic packages. Thermal resistances from the junction to the ambient were decreased from 79.6 to 46.7 $^{\circ}\hbox{C/W}$ by replacing the plastic mold with a ceramic mold for LED packages. Thermomechanical stress induced in the heat-block test was simulated using a finite-element method. Higher level of thermomechanical stress in the chip was found for LEDs with ceramic packages, despite less mismatching coefficients of thermal expansion, compared with that with plastic packages. The thermomechanical-stress components in the direction of the thickness were found to be larger than that in other two directions. The results suggest that the thermal performance of LEDs can be improved by using ceramic packages, but the mounting process of the high-power LEDs with ceramic packages is critically important and should be the reason for causing delaminating interface layers in the packages.

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