Defects in optoelectronic materials due to phosphorus-containing underlayer

Cheng, Wood-Hi; Chen, C. H.; Wang, S. C.; Tu, Yuan‐Kuang; Hsieh, Ker-Chang

doi:10.1007/s11664-998-0121-4

Cited by 2 publications

(2 citation statements)

References 4 publications

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“…These numerical simulation results are in good agreement with the experimental observation that cracks were observed for Invar with P-containing underlayer coating. 18 Therefore, the residual stress calculations of the FEM may provide one of the effective methods for predicting the crack formation in laser-welded Aucoated materials. In general, the low-melting phase with high P content may create relatively weak metallurgical structure regions which are subject to high shrinkage-induced strains.…”

Section: Fem Simulation Resultsmentioning

confidence: 99%

The principle cause of crack defects in optoelectronic materials with phosphorus-containing underlayer

Cheng

Sheen

Kuang

et al. 1999

Journal of Elec Materi

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The principle cause of cracks in laser-welded, Au-coated, optoelectronic materials with a phosphorus (P)-containing underlayer is studied experimentally and numerically modeled. Experimental results find that the crack formation is due to the existence of a P-containing underlayer and is not due to the thickness of the Au plating layer. The P-containing underlayer introduced by a electroless plating process may generate a low melting, P-rich segregation layer during solidification. A finite-element method analysis is performed to evaluate the residual stresses variation of the low melting P-rich segregation layer. Results show that the high residual tensile stresses of the P-rich segregation layer are generated by solidification shrinkage. A crack may be initiated by this residual stress. Both experimental observations and numerical calculations indicate that the crack formation mechanism in laser-welded Au-coated optoelectronic materials is directly related to the low melting P-rich segregation layer and its associated high tensile stresses. Based on these results, a Ni underlayer with Pfree electroplating, instead of P-containing electroless plating, should be used prior to plating Au on optoelectronic materials to prevent crack formation in laser welded Au-coated optoelectronic materials.

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Section: Fem Simulation Resultsmentioning

confidence: 99%

The principle cause of crack defects in optoelectronic materials with phosphorus-containing underlayer

Cheng

Sheen

Kuang

et al. 1999

Journal of Elec Materi

Self Cite

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show abstract

“…However, the chemical reducing agent of NaH PO is required in the electroless Ni plating process, resulting in P element in the Ni underlayer. Recently, comprehensive measurements of laserwelded Au-, Ni-, and Au/Ni-coated Invar suggest that the P element in the Ni underlayer may play a major role in determining the crack formation in laser welded Au-coated optoelectronic materials [16]. The exact mechanism of the effect of P and its association with Au coating on crack formation in laser welded Au-coated optoelectronic materials is currently under extensive investigation.…”

Section: Discussionmentioning

confidence: 99%

Crack formation mechanism in laser-welded Au-coated Invar materials for semiconductor laser packaging

Kuang

Sheen²,

Wang³

et al. 1999

IEEE Trans. Adv. Packag.

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Crack formation mechanism in laser-welded Aucoated Invar materials for semiconductor laser packaging is investigated experimentally and numerically. Experimental results obtained from metallography, scanning electron microscope (SEM), SEM mapping, and energy dispersive spectrometer (EDS) line profile show that high concentration of Au composition accumulate near the crack region. The cause of Au accumulation may come from the segregation of Au along the crack region. A finite-element method (FEM) is performed on the calculation of thermal stresses during spot-welding for Au-coated Invar materials. Numerical results show that the high tensile stresses of the Au segregation layer generated by rapid solidification shrinkage is the possible cause for crack formation. Both experimental and numerical results suggest that the crack formation mechanism in laser-welded Au-coated optoelectronic materials is directly related to the combined effects of the Au segregation and high tensile stresses induced by the strain shrinkage during the final stage of solidification.Index Terms-Finite-element method, laser welding, optoelectronic packaging, segregation.

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Defects in optoelectronic materials due to phosphorus-containing underlayer

Cited by 2 publications

References 4 publications

The principle cause of crack defects in optoelectronic materials with phosphorus-containing underlayer

The principle cause of crack defects in optoelectronic materials with phosphorus-containing underlayer

Crack formation mechanism in laser-welded Au-coated Invar materials for semiconductor laser packaging

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