There is an industrial interest to lower the costs of current manufacturing processes for printed SMD components. Through printing, resistive elements can be produced but the challenge remains with bumping. Replacing expensive metallization processes with printed copper pillars can potentially reduce product costs, processing steps, and facilitates flip-chip bonding.

Copper sintered pillars favor soldering unlike silver which suffers from diffusion of solders. Your assignment consists of an investigation of different processes for printing different sizes of copper pillars that are compatible with various SMD codes.

Project objective

Investigate different processes for printing different sizes of copper pillars that are compatible with various SMD codes. The expected project flow is as follows:

• Material scouting – exploring potential printable copper pastes and their curing processes (pressure/pressureless)
• Material testing – conduct some preliminary material tests to evaluate the bond strength to Ag
• Printing process analysis – evaluate screen/stencil printing resolution limitation using DEK printer at TNO/CITC and further explore photolithographic stencil printing [2] at TNO Holst Centre
• Prototype printing – demonstrate successful printing over a large substrate with SMD components
• Explore the advantages and drawbacks with comparison to other processes
• Final presentation internally at CITC and Master thesis defense

Note: the process of thesis writing goes hand-in-hand throughout the process flow

Internship and MSc thesis details

• Location: flexible at CITC in Nijmegen and TNO Holst Centre in Eindhoven
• Collaborators: CITC
• Duration: 6 – 8 months
• Requirements: current MSc students in Mechanical or Electrical Engineering
• Supervisors: Henry Antony Martin and Edsger Smits
• Internship stipend: standard internship stipend provided by CITC. Travel allowance can discussed