Thesis work: 30 hp - Microstructural investigation of solder joint failures in heavy-duty vehicles

Introduction
Thesis work is an excellent way to get closer to Scania and build relationships for the future. Many of today's employees began their Scania career with their degree project.

Background 
As vehicles will require more complex features, the need for higher computing power will increase, and thereby the need for intricate (and consequentially more fragile) electronics. One example is Ball Grid Array (BGA) on PCBAs, which are becoming more common due to their high pin density. A worry with BGAs is the reliability of their solder joints. Due to the CTE mismatch between the package and PCB substrate, changes in temperature will cause shear stress and fatigue. Temperature change frequently occurs over a vehicle’s lifetime, ex. at the start of a drive cycle. 

Today, we require use of underfill beneath BGAs to improve the fatigue life of their solder joints and provide environmental protection. Underfill is a significant cost driver, and we currently do not have a reliable method to determine if it is needed for a given installation in the vehicle. From experience, we know that the failure mode of BGA solder joint fracture are sometimes not detected from our standardized tests, and we therefore need to expand our knowledge within this field. One way of relating remaining lifetime is to analyse the microstructure of its solder joint.

Objective 
The purpose of the thesis is to study the active failure mechanism of EEE-components both from the field and from testing in lab. 

Job description 
The work will include experiments, such as random mechanical vibration and temperature cycling, and material analysis through LOM, SEM, X-ray, EDX. 

Education/program/focus
MSc. in Material Science, Applied Physics, Mechanical Engineering. 
Number of students: 1
Start date for the thesis work: TBD
Estimated time required: 20 weeks full-time (30 hp)

Contact persons and supervisors
Manager: Gonvel Kako (gonvel.kako@scania.com), 
Test Engineer: Alexander Hillström (alexander.hillstrom@scania.com) 
Test Engineer: Peter Harris (peter.x.harris@scania.com)  

Application:
Your application must include a CV, personal letter and transcript of grades 

A background check might be conducted for this position. We are conducting interviews continuously and may close the recruitment earlier than the date specified.