Prevention of Cu Electrolytic Migration Defects on RDL by a Cu-Selective Passivation to Enhance Reliability.

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Bibliographic Details
Title:	Prevention of Cu Electrolytic Migration Defects on RDL by a Cu-Selective Passivation to Enhance Reliability.
Authors:	Salunke, Ashish S.¹ ashishshivajisalunke@my.unt.edu, Alptekin, John¹, Akula, Kaushik¹, Jayakumar, Subiksha¹, Kumar, Shaurya¹, Chyan, Oliver¹
Source:	Journal of Microelectronic & Electronic Packaging. 2023, Vol. 20 Issue 1, p17-26. 10p.
Subjects:	Copper ions, Wafer level packaging, Electrodes, Electrochemical analysis, Dendritic crystals
Abstract:	Copper (Cu) is the metal of choice for the redistribution layer (RDL) to facilitate fast I/O communication in an integrated circuit (IC). Cu can electrochemically migrate (ECM) between the array of electrodes under bias, electrolyte, and moisture. IC packages fail miserably when exposed to various ion impurities and moisture. Copper at the anode dissolves to form Cu+1 and Cu+2 ions. As the anodic dissolution continues, the concentration of copper ion increases. These anions deposit on the cathode leading to Cu dendrite formation. To achieve the nearzero parts per billion defectivity goal, elimination of ECM defects in packaged devices is critical. This work discusses the development of a novel Cu-selective passivation and a method to accelerate reliability testing. A hydrophobic passivation with minimum stress to the IC package is proposed in this work. The new passivation coating is thermally stable, strongly adheres to Cu, is corrosion resistant, low cost, and shows good potential to prevent ECM defects. The coated packaged devices were tested by an accelerated PEG drop test (PDT) to explore its ECM prevention capabilities. [ABSTRACT FROM AUTHOR]
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Database:	Engineering Source

Description
Abstract:	Copper (Cu) is the metal of choice for the redistribution layer (RDL) to facilitate fast I/O communication in an integrated circuit (IC). Cu can electrochemically migrate (ECM) between the array of electrodes under bias, electrolyte, and moisture. IC packages fail miserably when exposed to various ion impurities and moisture. Copper at the anode dissolves to form Cu+1 and Cu+2 ions. As the anodic dissolution continues, the concentration of copper ion increases. These anions deposit on the cathode leading to Cu dendrite formation. To achieve the nearzero parts per billion defectivity goal, elimination of ECM defects in packaged devices is critical. This work discusses the development of a novel Cu-selective passivation and a method to accelerate reliability testing. A hydrophobic passivation with minimum stress to the IC package is proposed in this work. The new passivation coating is thermally stable, strongly adheres to Cu, is corrosion resistant, low cost, and shows good potential to prevent ECM defects. The coated packaged devices were tested by an accelerated PEG drop test (PDT) to explore its ECM prevention capabilities. [ABSTRACT FROM AUTHOR]
ISSN:	15514897
DOI:	10.4071/imaps.1903845