Investigation of stress relaxation in SAC305 with micro-Raman spectroscopy. (November 2022)

• Record Type: Journal Article
• Authors: Liu, E; Bhogaraju, Sri Krishna; Wunderle, Bernhard; Elger, Gordon
• Is Part Of: Microelectronics and reliability. Volume 138(2022)
• Publication Date: 2022-11
• Subjects: Creep -- FE modelling -- Raman spectroscopy -- Reliability -- Thermo-mechanical fatigue; Electronic apparatus and appliances -- Reliability -- Periodicals; Miniature electronic equipment -- Periodicals; Appareils électroniques -- Fiabilité -- Périodiques; Équipement électronique miniaturisé -- Périodiques; Electronic apparatus and appliances -- Reliability; Miniature electronic equipment; Periodicals; 621.3815
• DOI: 10.1016/j.microrel.2022.114664
• Languages: English
• ISSNs: 0026-2714

Abstract

Abstract: In the paper, μ-Raman spectroscopy is applied as non-destructive test method to access the creep in chip interconnection materials. To develop the method, a silicon test chip is soldered onto a copper substrate using SAC305 and the strain of the silicon crystal in the top surface of the chip is measured time dependent after assembly by the Raman shift. The in-plane stress in silicon crystal decreased exponentially within several days after soldering. To access the strain in the solder material a finite element model was calibrated based on the experimental data applying the Anand creep model and fitting its parameter. The analysis reveals the applicability of μ-Raman measurement to assess creep within interconnect material in microelectronic assemblies. Highlights: Creep in solder joints Raman spectroscopy Stress and strain measurements FE analysis