Master Thesis: Characterising SAC305 BGA Solder-Joint Defects for Electronics Reliability
Scania GroupRekommenderat
Sammanfattning
This master's thesis project at TRATON R&D focuses on the reliability of electronic assemblies, specifically investigating defects in BGA solder joints using advanced imaging techniques. The student will analyze CT data, perform microscopy, and correlate findings to enhance understanding of solder-joint reliability. The role is based in Södertälje, Sweden, and is expected to last from January to June 2027.Jobbet i korthet
Arbetstid
heltid/deltid
Det här erbjuder vi
Opportunity to apply academic knowledge to industrial challenges.Gain experience in advanced imaging and microstructural analysis.Work under the supervision of experienced professionals in the field.
Ansök senast: Öppet tillsvidare
Publicerad: 2026-11-12
Beskrivning
30hp - Characterising SAC305 BGA Solder-Joint Defects for Electronics Reliability: A Correlative Study Using X-ray CT, Polarized-Light Optical Microscopy, SEM and EBSD
Introduction
A master's thesis is an opportunity to apply academic knowledge to an industrial challenge and gain experience working with TRATON R&D. This project focuses on the reliability of electronic assemblies, using advanced imaging and microstructural analysis to improve understanding of defects in BGA solder joints.
Background
Cross-sectional analysis has traditionally been used to examine solder-joint defects, but it provides information from only a limited plane. X-ray computed tomography (CT) can reveal internal features in three dimensions, yet the nature and significance of some CT indications may be unclear without further investigation.
The project will use a thermally cycled SAC305 BGA with a few hundred solder balls as a case study. CT indications will be mapped and selected features investigated through targeted cross-sectioning. Polarized-light optical microscopy, scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) will be used to examine the defects and surrounding solder microstructure.
The work will provide a foundation for future studies of how solder-joint defects relate to electronic reliability. The case study will focus on interpreting and correlating observed features.
Objective
Job description
The student will first review the CT data from the BGA and map the locations of relevant indications. Based on these observations, selected solder joints will be sectioned and prepared for microscopy.
The student will use polarized-light optical microscopy to examine solder-grain structure and use SEM and EBSD to investigate selected defects, crack features and the surrounding microstructure. CT and microscopy observations will then be compared to determine what the CT features represent and how well they can be located for further analysis.
The work will include planning and carrying out sample preparation, image analysis, interpretation of results and preparation of a final thesis report and presentation. The project combines electronics reliability, materials characterization and practical laboratory work.
Education/program/focus
The project is suitable for a student in the final year of a Master's program in Materials Science and Engineering, Mechanical Engineering, Manufacturing Engineering, Electrical Engineering or a related field.
Interest in electronic materials, solder-joint reliability and microstructure characterization is important. Previous experience with optical microscopy, SEM, EBSD, X-ray CT or metallographic sample preparation is an advantage, but a willingness to learn these techniques is also welcome. The student should be analytical, self-driven and comfortable working independently in a research environment.
Number of students: 1
Start date: January, 2027
Estimated duration: until June, 2027
Contact persons and supervisors
Traton Supervisor: Hongjie Li, Electronics Material Engineer, Material Technology, Traton AB
Application:
Your application must include a CV, personal letter and transcript.
For questions, please contact Hongjie Li, PhD, Hongjie.li@scania.com and Öystein Krogen, Unit Manager, oystein.krogen@scania.com. A background check might be conducted for this position. We are conducting interviews continuously and may close the recruitment earlier than the date specified.
Requisition ID: 35134
Number of Openings: 1.0
Part-time / Full-time: Full-time
Permanent / Temporary: Temporary
Country / Region: SE
Location(s):
Södertälje, SE, 151 38
Required Travel: 0%
Workplace: On-site
Introduction
A master's thesis is an opportunity to apply academic knowledge to an industrial challenge and gain experience working with TRATON R&D. This project focuses on the reliability of electronic assemblies, using advanced imaging and microstructural analysis to improve understanding of defects in BGA solder joints.
Background
Cross-sectional analysis has traditionally been used to examine solder-joint defects, but it provides information from only a limited plane. X-ray computed tomography (CT) can reveal internal features in three dimensions, yet the nature and significance of some CT indications may be unclear without further investigation.
The project will use a thermally cycled SAC305 BGA with a few hundred solder balls as a case study. CT indications will be mapped and selected features investigated through targeted cross-sectioning. Polarized-light optical microscopy, scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) will be used to examine the defects and surrounding solder microstructure.
The work will provide a foundation for future studies of how solder-joint defects relate to electronic reliability. The case study will focus on interpreting and correlating observed features.
Objective
- Identify and document internal features and potential defects observed in the BGA solder joints using X-ray CT.
- Assess how accurately selected CT indications can be located and examined through targeted cross-sectioning.
- Characterize the selected features and surrounding SAC305 microstructure using polarized-light optical microscopy, SEM and EBSD.
- Correlate the three-dimensional CT observations with the corresponding cross-sectional and microstructural evidence.
- Develop a practical workflow for future correlative CT and microstructure studies of BGA solder joints.
Job description
The student will first review the CT data from the BGA and map the locations of relevant indications. Based on these observations, selected solder joints will be sectioned and prepared for microscopy.
The student will use polarized-light optical microscopy to examine solder-grain structure and use SEM and EBSD to investigate selected defects, crack features and the surrounding microstructure. CT and microscopy observations will then be compared to determine what the CT features represent and how well they can be located for further analysis.
The work will include planning and carrying out sample preparation, image analysis, interpretation of results and preparation of a final thesis report and presentation. The project combines electronics reliability, materials characterization and practical laboratory work.
Education/program/focus
The project is suitable for a student in the final year of a Master's program in Materials Science and Engineering, Mechanical Engineering, Manufacturing Engineering, Electrical Engineering or a related field.
Interest in electronic materials, solder-joint reliability and microstructure characterization is important. Previous experience with optical microscopy, SEM, EBSD, X-ray CT or metallographic sample preparation is an advantage, but a willingness to learn these techniques is also welcome. The student should be analytical, self-driven and comfortable working independently in a research environment.
Number of students: 1
Start date: January, 2027
Estimated duration: until June, 2027
Contact persons and supervisors
Traton Supervisor: Hongjie Li, Electronics Material Engineer, Material Technology, Traton AB
Application:
Your application must include a CV, personal letter and transcript.
For questions, please contact Hongjie Li, PhD, Hongjie.li@scania.com and Öystein Krogen, Unit Manager, oystein.krogen@scania.com. A background check might be conducted for this position. We are conducting interviews continuously and may close the recruitment earlier than the date specified.
Requisition ID: 35134
Number of Openings: 1.0
Part-time / Full-time: Full-time
Permanent / Temporary: Temporary
Country / Region: SE
Location(s):
Södertälje, SE, 151 38
Required Travel: 0%
Workplace: On-site
Ansök till tjänsten
Master Thesis: Characterising SAC305 BGA Solder-Joint Defects for Electronics Reliability
Rekommenderat
OM FÖRETAGET
Scania Group
